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Journal Cover Advanced Materials
  [SJR: 9.021]   [H-I: 345]   [282 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0935-9648 - ISSN (Online) 1521-4095
   Published by John Wiley and Sons Homepage  [1592 journals]
  • Amorphizing of Cu Nanoparticles toward Highly Efficient and Robust
           Electrocatalyst for CO2 Reduction to Liquid Fuels with High Faradaic
           Efficiencies
    • Authors: Yan-Xin Duan; Fan-Lu Meng, Kai-Hua Liu, Sha-Sha Yi, Si-Jia Li, Jun-Min Yan, Qing Jiang
      Abstract: Conversion of carbon dioxide (CO2) into valuable chemicals, especially liquid fuels, through electrochemical reduction driven by sustainable energy sources, is a promising way to get rid of dependence on fossil fuels, wherein developing of highly efficient catalyst is still of paramount importance. In this study, as a proof-of-concept experiment, first a facile while very effective protocol is proposed to synthesize amorphous Cu NPs. Unexpectedly, superior electrochemical performances, including high catalytic activity and selectivity of CO2 reduction to liquid fuels are achieved, that is, a total Faradaic efficiency of liquid fuels can sum up to the maximum value of 59% at −1.4 V, with formic acid (HCOOH) and ethanol (C2H6O) account for 37% and 22%, respectively, as well as a desirable long-term stability even up to 12 h. More importantly, this work opens a new avenue for improved electroreduction of CO2 based on amorphous metal catalysts.An amorphous Cu catalyst displays superior catalytic activity toward electroreduction of CO2 with a remarkable selectivity for the reduction to liquid fuels (HCOOH andC2H6O) relative to a crystalline Cu catalyst.
      PubDate: 2018-02-23T03:05:44.917217-05:
      DOI: 10.1002/adma.201706194
       
  • Engineering Extracellular Vesicles with the Tools of Enzyme Prodrug
           Therapy
    • Authors: Gregor Fuhrmann; Rona Chandrawati, Paresh A. Parmar, Timothy J. Keane, Stephanie A. Maynard, Sergio Bertazzo, Molly M. Stevens
      Abstract: Extracellular vesicles (EVs) have recently gained significant attention as important mediators of intercellular communication, potential drug carriers, and disease biomarkers. These natural cell-derived nanoparticles are postulated to be biocompatible, stable under physiological conditions, and to show reduced immunogenicity as compared to other synthetic nanoparticles. Although initial clinical trials are ongoing, the use of EVs for therapeutic applications may be limited due to undesired off-target activity and potential “dilution effects” upon systemic administration which may affect their ability to reach their target tissues. To fully exploit their therapeutic potential, EVs are embedded into implantable biomaterials designed to achieve local delivery of therapeutics taking advantage of enzyme prodrug therapy (EPT). In this first application of EVs for an EPT approach, EVs are used as smart carriers for stabilizing enzymes in a hydrogel for local controlled conversion of benign prodrugs to active antiinflammatory compounds. It is shown that the natural EVs' antiinflammatory potential is comparable or superior to synthetic carriers, in particular upon repeated long-term incubations and in different macrophage models of inflammation. Moreover, density-dependent color scanning electron microscopy imaging of EVs in a hydrogel is presented herein, an impactful tool for further understanding EVs in biological settings.Extracellular vesicles (EVs) are exploited as drug delivery vehicles but their therapeutic use may be limited due to off-target effects. To harness EVs' inherent properties and to couple them with site-specific drug delivery functions, EVs are incorporated into hydrogels and engineered with the tools of enzyme prodrug therapy. Local sustained release of antiinflammatory drugs is demonstrated in macrophage cell models.
      PubDate: 2018-02-23T03:01:45.071579-05:
      DOI: 10.1002/adma.201706616
       
  • Quantum Emitters in Hexagonal Boron Nitride Have Spectrally Tunable
           Quantum Efficiency
    • Authors: Andreas W. Schell; Mikael Svedendahl, Romain Quidant
      Abstract: Understanding the properties of novel solid-state quantum emitters is pivotal for a variety of applications in research fields ranging from quantum optics to biology. Recently discovered defects in hexagonal boron nitride are especially interesting, as they offer much desired characteristics such as narrow emission lines and photostability. Here, the dependence of the emission on the excitation wavelength is studied. It is found that, in order to achieve bright single-photon emission with high quantum efficiency, the excitation wavelength has to be matched to the emitter. This is a strong indication that the emitters possess a complex level scheme and cannot be described by a simple two or three-level system. Using this excitation dependence of the emission, further insight to the internal level scheme is gained and it is demonstrated how to distinguish different emitters both spatially as well as in terms of their photon correlations.Quantum emitters in hexagonal boron nitride are studied under excitation by light of different wavelengths. It is shown that single photons are emitted with different rates depending on the excitation energy and, in addition, the quantum efficiency changes. These findings are, for instance, important for future implementations of these emitters in quantum-information-processing schemes.
      PubDate: 2018-02-23T03:01:08.385646-05:
      DOI: 10.1002/adma.201704237
       
  • Oxide Thin-Film Electronics using All-MXene Electrical Contacts
    • Authors: Zhenwei Wang; Hyunho Kim, Husam N. Alshareef
      Abstract: 2D MXenes have shown great promise in electrochemical and electromagnetic shielding applications. However, their potential use in electronic devices is significantly less explored. The unique combination of metallic conductivity and hydrophilic surface suggests that MXenes can also be promising in electronics and sensing applications. Here, it is shown that metallic Ti3C2 MXene with work function of 4.60 eV can make good electrical contact with both zinc oxide (ZnO) and tin monoxide (SnO) semiconductors, with negligible band offsets. Consequently, both n-type ZnO and p-type SnO thin-film transistors (TFTs) have been fabricated entirely using large-area MXene (Ti3C2) electrical contacts, including gate, source, and drain. The n- and p-type TFTs show balanced performance, including field-effect mobilities of 2.61 and 2.01 cm2 V−1 s−1 and switching ratios of 3.6 × 106 and 1.1 × 103, respectively. Further, complementary metal oxide semiconductor (CMOS) inverters are demonstrated. The CMOS inverters show large voltage gain of 80 and excellent noise margin of 3.54 V, which is 70.8% of the ideal value. Moreover, the operation of CMOS inverters is shown to be very stable under a 100 Hz square waveform input. The current results suggest that MXene (Ti3C2) can play an important role as contact material in nanoelectronics.MXene (Ti3C2) thin film is used for the first time as the electrical contacts (gate, source, and drain) for both n- and p-type thin-film transistors (TFT). The n- and p-type TFTs show reasonably good and balanced performance. A complementary metal oxide semiconductor device is further demonstrated, showing good static (high gain, excellent noise margin) and dynamic switching performance.
      PubDate: 2018-02-23T03:00:51.49296-05:0
      DOI: 10.1002/adma.201706656
       
  • Highly Augmented Drug Loading and Stability of Micellar Nanocomplexes
           Composed of Doxorubicin and Poly(ethylene glycol)–Green Tea Catechin
           Conjugate for Cancer Therapy
    • Authors: Kun Liang; Joo Eun Chung, Shu Jun Gao, Nunnarpas Yongvongsoontorn, Motoichi Kurisawa
      Abstract: Low drug loading and instability in blood circulation are two key challenges that impede the successful clinical translation of nanomedicine, as they result in only marginal therapeutic efficacy and toxic side effects associated with premature drug leakage, respectively. Herein, highly stable and ultrahigh drug loading micellar nanocomplexes (MNCs) based on the self-assembly of the anticancer drug doxorubicin (DOX) and a poly(ethylene glycol)–epigallocatechin-3-O-gallate (EGCG) conjugate are developed. The formation of these MNCs is facilitated by strong favorable intermolecular interactions between the structurally similar aromatic EGCG and DOX molecules, which impart exceptionally high drug-loading capability of up to 88% and excellent thermodynamic and kinetic stability. Unlike two clinical formulations of DOX—free DOX and liposomal DOX, which are not effective below their lethal dosages, these DOX-loaded MNCs demonstrate significant tumor growth inhibition in vivo on a human liver cancer xenograft mouse model with minimal unwanted toxicity. Overall, these MNCs can represent a safe and effective strategy to deliver DOX for cancer therapy.Self-assembled micellar nanocomplexes (MNCs) leverage the favorable interaction between the structurally similar green tea catechin (epigallocatechin-3-O-gallate) and small-molecular anticancer drug doxorubicin (DOX) to attain ultrahigh drug loading capacity and stability in circulation. These DOX-loaded MNCs demonstrate significant antitumor activity with attenuated toxicity, enabling a safe and effective strategy for cancer therapy.
      PubDate: 2018-02-23T02:56:14.339546-05:
      DOI: 10.1002/adma.201706963
       
  • Direct Growth of Highly Stable Patterned Graphene on Dielectric Insulators
           using a Surface-Adhered Solid Carbon Source
    • Authors: Eunho Lee; Seung Goo Lee, Hyo Chan Lee, Mankyu Jo, Min Seok Yoo, Kilwon Cho
      Abstract: A novel method is described for the direct growth of patterned graphene on dielectric substrates by chemical vapor deposition (CVD) in the presence of Cu vapor and using a solid aromatic carbon source, 1,2,3,4-tetraphenylnapthalene (TPN), as the precursor. The UV/O3 treatment of the TPN film both crosslinks TPN and results in a strong interaction between the substrate and the TPN that prevents complete sublimation of the carbon source from the substrate during CVD. Substrate-adhered crosslinked TPN is successfully converted to graphene on the substrate without any organic contamination. The graphene synthesized by this method shows excellent mechanical and chemical stability. This process also enables the simultaneous patterning of graphene materials, which can thus be used as transparent electrodes for electronic devices. The proposed method for the synthesis directly on substrates of patterned graphene is expected to have wide applications in organic and soft hybrid electronics.Highly stable patterned graphene is directly synthesized on insulator substrates via a chemical vapor deposition method using a surface-adhered solid polycyclic aromatic hydrocarbon source. The synthesized graphene is strongly bound to the substrate by interfacial adhesion bonding resulting from UV/ozone pretreament. It successfully leads to improve the mechanical/chemical stability of the synthesized graphene.
      PubDate: 2018-02-23T02:55:57.062922-05:
      DOI: 10.1002/adma.201706569
       
  • Highly Confined and Tunable Hyperbolic Phonon Polaritons in Van Der Waals
           Semiconducting Transition Metal Oxides
    • Authors: Zebo Zheng; Jianing Chen, Yu Wang, Ximiao Wang, Xiaobo Chen, Pengyi Liu, Jianbin Xu, Weiguang Xie, Huanjun Chen, Shaozhi Deng, Ningsheng Xu
      Abstract: 2D van der Waals (vdW) layered polar crystals sustaining phonon polaritons (PhPs) have opened up new avenues for fundamental research and optoelectronic applications in the mid-infrared to terahertz ranges. To date, 2D vdW crystals with PhPs are only experimentally demonstrated in hexagonal boron nitride (hBN) slabs. For optoelectronic and active photonic applications, semiconductors with tunable charges, finite conductivity, and moderate bandgaps are preferred. Here, PhPs are demonstrated with low loss and ultrahigh electromagnetic field confinements in semiconducting vdW α-MoO3. The α-MoO3 supports strong hyperbolic PhPs in the mid-infrared range, with a damping rate as low as 0.08. The electromagnetic confinements can reach ≈λ0/120, which can be tailored by altering the thicknesses of the α-MoO3 2D flakes. Furthermore, spatial control over the PhPs is achieved with a metal-ion-intercalation strategy. The results demonstrate α-MoO3 as a new platform for studying hyperbolic PhPs with tunability, which enable switchable mid-infrared nanophotonic devices.A van der Waals transition metal oxide, α-MoO3, is demonstrated as a new natural hyperbolic material, which can sustain low-loss phonon polaritons (PhPs) with ultrahigh electromagnetic confinements in the mid-infrared region. The α-MoO3 PhPs can be tailored by either altering the thicknesses of the flake or metal ion intercalations.
      PubDate: 2018-02-22T07:46:50.369751-05:
      DOI: 10.1002/adma.201705318
       
  • Promises, Challenges, and Recent Progress of Inorganic Solid-State
           Electrolytes for All-Solid-State Lithium Batteries
    • Authors: Zhonghui Gao; Huabin Sun, Lin Fu, Fangliang Ye, Yi Zhang, Wei Luo, Yunhui Huang
      Abstract: All-solid-state lithium batteries (ASSLBs) have the potential to revolutionize battery systems for electric vehicles due to their benefits in safety, energy density, packaging, and operable temperature range. As the key component in ASSLBs, inorganic lithium-ion-based solid-state electrolytes (SSEs) have attracted great interest, and advances in SSEs are vital to deliver the promise of ASSLBs. Herein, a survey of emerging SSEs is presented, and ion-transport mechanisms are briefly discussed. Techniques for increasing the ionic conductivity of SSEs, including substitution and mechanical strain treatment, are highlighted. Recent advances in various classes of SSEs enabled by different preparation methods are described. Then, the issues of chemical stabilities, electrochemical compatibility, and the interfaces between electrodes and SSEs are focused on. A variety of research addressing these issues is outlined accordingly. Given their importance for next-generation battery systems and transportation style, a perspective on the current challenges and opportunities is provided, and suggestions for future research directions for SSEs and ASSLBs are suggested.Inorganic solid-state electrolytes (SSEs) offer numerous advantages for the development of next-generation batteries. The most promising advantages are the safety that benefits from the nonflammable nature of SSEs and the possibility of using a Li-metal anode, which has highest capacity, lowest anodic potential, and is indispensable to the future success of high-energy-density Li–S batteries and Li–O2 battery systems.
      PubDate: 2018-02-22T02:27:47.744586-05:
      DOI: 10.1002/adma.201705702
       
  • Biocompatible Semiconductor Quantum Dots as Cancer Imaging Agents
    • Authors: Kevin J. McHugh; Lihong Jing, Adam M. Behrens, Surangi Jayawardena, Wen Tang, Mingyuan Gao, Robert Langer, Ana Jaklenec
      Abstract: Approximately 1.7 million new cases of cancer will be diagnosed this year in the United States leading to 600 000 deaths. Patient survival rates are highly correlated with the stage of cancer diagnosis, with localized and regional remission rates that are much higher than for metastatic cancer. The current standard of care for many solid tumors includes imaging and biopsy with histological assessment. In many cases, after tomographical imaging modalities have identified abnormal morphology consistent with cancer, surgery is performed to remove the primary tumor and evaluate the surrounding lymph nodes. Accurate identification of tumor margins and staging are critical for selecting optimal treatments to minimize recurrence. Visible, fluorescent, and radiolabeled small molecules have been used as contrast agents to improve detection during real-time intraoperative imaging. Unfortunately, current dyes lack the tissue specificity, stability, and signal penetration needed for optimal performance. Quantum dots (QDs) represent an exciting class of fluorescent probes for optical imaging with tunable optical properties, high stability, and the ability to target tumors or lymph nodes based on surface functionalization. Here, state-of-the-art biocompatible QDs are compared with current Food and Drug Administration approved fluorophores used in cancer imaging and a perspective on the pathway to clinical translation is provided.Near-infrared quantum dots have the potential to serve as superior contrast agents for intraoperative optical imaging during tumor resection and lymph node biopsy compared with current dyes approved by the Food and Drug Administration. By modulating the size, composition, and surface functionalization, quantum dots can emit at wavelengths with superior tissue penetration and preferentially target a tumor or lymph nodes to improve imaging contrast.
      PubDate: 2018-02-22T02:26:37.269423-05:
      DOI: 10.1002/adma.201706356
       
  • Bioinspired Wood Nanotechnology for Functional Materials
    • Authors: Lars A. Berglund; Ingo Burgert
      Abstract: It is a challenging task to realize the vision of hierarchically structured nanomaterials for large-scale applications. Herein, the biomaterial wood as a large-scale biotemplate for functionalization at multiple scales is discussed, to provide an increased property range to this renewable and CO2-storing bioresource, which is available at low cost and in large quantities. The Progress Report reviews the emerging field of functional wood materials in view of the specific features of the structural template and novel nanotechnological approaches for the development of wood–polymer composites and wood–mineral hybrids for advanced property profiles and new functions.Wood, as a biomaterial, can be used as a large-scale bioscaffold and template for functionalization at multiple scales in a top-down approach. This emerging research field is reviewed by discussing nanotechnological approaches for the development of wood–polymer composites and wood–mineral hybrids, as well as wood-based devices for advanced property profiles and new functions.
      PubDate: 2018-02-22T02:22:25.749856-05:
      DOI: 10.1002/adma.201704285
       
  • Characterization and Manipulation of Spin Orbit Torque in Magnetic
           Heterostructures
    • Authors: Xuepeng Qiu; Zhong Shi, Weijia Fan, Shiming Zhou, Hyunsoo Yang
      Abstract: Electrical-current-induced magnetization switching is a keystone concept in the development of spintronics devices. In the last few years, this field has experienced a significant boost with the discovery of spin orbit torque (SOT) in magnetic heterostructures. Here, the recent results as to the characterization and manipulation of SOT in various heavy-metal/ferromagnet heterostructures are summarized. First, different electrical measurement methods that allow the physical features of SOT to be revealed are introduced. Second, it is shown that SOT in magnetic heterostructures can be manipulated via various material engineering approaches. The interfacial and bulk contributions of SOT are also discussed. These results advance the understanding of SOT and provide novel approaches toward energy-efficient spintronic devices.Spin orbit torque (SOT) is emerging as an efficient magnetic-state control strategy for widespread modern memory and logic applications that are nonvolatile, scalable, and ultrafast. Recent developments on the characterization and manipulation of SOT in magnetic heterostructures are described, which lay the foundation for new-generation spintronic devices.
      PubDate: 2018-02-22T02:21:49.761126-05:
      DOI: 10.1002/adma.201705699
       
  • Superhydrophobic Blood-Repellent Surfaces
    • Authors: Ville Jokinen; Esko Kankuri, Sasha Hoshian, Sami Franssila, Robin H. A. Ras
      Abstract: Superhydrophobic surfaces repel water and, in some cases, other liquids as well. The repellency is caused by topographical features at the nano-/microscale and low surface energy. Blood is a challenging liquid to repel due to its high propensity for activation of intrinsic hemostatic mechanisms, induction of coagulation, and platelet activation upon contact with foreign surfaces. Imbalanced activation of coagulation drives thrombogenesis or formation of blood clots that can occlude the blood flow either on-site or further downstream as emboli, exposing tissues to ischemia and infarction. Blood-repellent superhydrophobic surfaces aim toward reducing the thrombogenicity of surfaces of blood-contacting devices and implants. Several mechanisms that lead to blood repellency are proposed, focusing mainly on platelet antiadhesion. Structured surfaces can: (i) reduce the effective area exposed to platelets, (ii) reduce the adhesion area available to individual platelets, (iii) cause hydrodynamic effects that reduce platelet adhesion, and (iv) reduce or alter protein adsorption in a way that is not conducive to thrombus formation. These mechanisms benefit from the superhydrophobic Cassie state, in which a thin layer of air is trapped between the solid surface and the liquid. The connections between water- and blood repellency are discussed and several recent examples of blood-repellent superhydrophobic surfaces are highlighted.Superhydrophobic surfaces can reduce the adhesion and activation of platelets and thus show promise for blood-repellent surfaces. The micro- and nanotopographies reduce the effective area exposed to blood and provide insufficient adhesion areas for platelets. Superhydrophobic surfaces also alter protein adsorption and flow patterns. However, questions remain regarding the safety and stability in physiological conditions.
      PubDate: 2018-02-21T07:56:43.826055-05:
      DOI: 10.1002/adma.201705104
       
  • Self-Assembled Peptide-Based Nanomaterials for Biomedical Imaging and
           Therapy
    • Authors: Guo-Bin Qi; Yu-Juan Gao, Lei Wang, Hao Wang
      Abstract: Peptide-based materials are one of the most important biomaterials, with diverse structures and functionalities. Over the past few decades, a self-assembly strategy is introduced to construct peptide-based nanomaterials, which can form well-controlled superstructures with high stability and multivalent effect. More recently, peptide-based functional biomaterials are widely utilized in clinical applications. However, there is no comprehensive review article that summarizes this growing area, from fundamental research to clinic translation. In this review, the recent progress of peptide-based materials, from molecular building block peptides and self-assembly driving forces, to biomedical and clinical applications is systematically summarized. Ex situ and in situ constructed nanomaterials based on functional peptides are presented. The advantages of intelligent in situ construction of peptide-based nanomaterials in vivo are emphasized, including construction strategy, nanostructure modulation, and biomedical effects. This review highlights the importance of self-assembled peptide nanostructures for nanomedicine and can facilitate further knowledge and understanding of these nanosystems toward clinical translation.The recent progress in peptide-based nanomaterials from building block peptides and self-assembly driving forces to application-directed ex situ and in situ construction of nanomaterials is systematically summarized. The advantages of intelligent in situ construction of peptide-based nanomaterials in vivo are emphasized. The importance of self-assembled peptide nanostructures for nanomedicine is highlighted.
      PubDate: 2018-02-20T03:03:01.475027-05:
      DOI: 10.1002/adma.201703444
       
  • Tattoo-Paper Transfer as a Versatile Platform for All-Printed Organic
           Edible Electronics
    • Authors: Giorgio E. Bonacchini; Caterina Bossio, Francesco Greco, Virgilio Mattoli, Yun-Hi Kim, Guglielmo Lanzani, Mario Caironi
      Abstract: The use of natural or bioinspired materials to develop edible electronic devices is a potentially disruptive technology that can boost point-of-care testing. The technology exploits devices that can be safely ingested, along with pills or even food, and operated from within the gastrointestinal tract. Ingestible electronics can potentially target a significant number of biomedical applications, both as therapeutic and diagnostic tool, and this technology may also impact the food industry, by providing ingestible or food-compatible electronic tags that can “smart” track goods and monitor their quality along the distribution chain. Temporary tattoo-paper is hereby proposed as a simple and versatile platform for the integration of electronics onto food and pharmaceutical capsules. In particular, the fabrication of all-printed organic field-effect transistors on untreated commercial tattoo-paper, and their subsequent transfer and operation on edible substrates with a complex nonplanar geometry is demonstrated.Temporary tattoo-paper is proposed as a simple and versatile platform for the integration of biocompatible organic electronics onto food and pharmaceutical capsules. The fabrication of all-printed biocompatible organic transistors and complementary logic on untreated commercial tattoo-paper, and their subsequent transfer to and operation on edible substrates is demonstrated, paving the way for novel point-of-care devices and smart food labels.
      PubDate: 2018-02-20T02:00:04.528223-05:
      DOI: 10.1002/adma.201706091
       
  • Contents: (Adv. Mater. 8/2018)
    • PubDate: 2018-02-19T06:01:59.357653-05:
      DOI: 10.1002/adma.201870051
       
  • Theranostics: Light-Responsive Biodegradable Nanorattles for Cancer
           Theranostics (Adv. Mater. 8/2018)
    • Authors: Chunxiao Li; Yifan Zhang, Zhiming Li, Enci Mei, Jing Lin, Fan Li, Cunguo Chen, Xialing Qing, Liyue Hou, Lingling Xiong, Hui Hao, Yun Yang, Peng Huang
      Abstract: In article number 1706150, Zhiming Li, Yun Yang, Peng Huang, and co-workers report a light-responsive biodegradable nanorattle, a perfluoropentane-filled mesoporous-silica-film-coated gold nanorod, for enhanced ultrasound (US)/photoacoustic (PA) dual-modality-imaging-guided photothermal therapy of melanoma. This cancer nanotheranostic platform exhibits excellent biocompatibility and biodegradability, a distinct gas-bubbling phenomenon, good US/PA imaging contrast, and remarkable photothermal efficiency.
      PubDate: 2018-02-19T06:01:57.84679-05:0
      DOI: 10.1002/adma.201870049
       
  • Photoswitchable Proton Conduction: Switching the Proton Conduction in
           Nanoporous, Crystalline Materials by Light (Adv. Mater. 8/2018)
    • Authors: Kai Müller; Julian Helfferich, Fangli Zhao, Rupal Verma, Anemar Bruno Kanj, Velimir Meded, David Bléger, Wolfgang Wenzel, Lars Heinke
      Abstract: Proton-conducting molecules in the pores of metal–organic frameworks change their conductivity upon photoswitching the host framework. In work by Lars Heinke and co-workers presented in article number 1706551, irradiation with light (green) causes trans–cis isomerization of the azobenzene components of the framework, switching the molecular interaction and the conductivity of the triazole guest molecules (center). The sample is mounted on interdigitated gold electrodes, which are used for measuring the conductivity.
      PubDate: 2018-02-19T06:01:57.186537-05:
      DOI: 10.1002/adma.201870055
       
  • Chiral Switches: Piecewise Phototuning of Self-Organized Helical
           Superstructures (Adv. Mater. 8/2018)
    • Authors: Lang Qin; Wei Gu, Jia Wei, Yanlei Yu
      Abstract: Colorful patterns with a black background are realized based on piecewise reflection tuning of cholesteric liquid crystals induced by a newly designed photoresponsive tristable chiral switch. In article number 1704941, Yanlei Yu and co-workers find that the three stable configurations of the chiral switch endow the system with two continuous and adjacent tuning periods of the reflection, covering not only the entire visible spectrum, but also a further wide period within near-infrared region.
      PubDate: 2018-02-19T06:01:54.15488-05:0
      DOI: 10.1002/adma.201870050
       
  • Masthead: (Adv. Mater. 8/2018)
    • PubDate: 2018-02-19T06:01:49.527039-05:
      DOI: 10.1002/adma.201870052
       
  • Solar Cells: Self-Organized Superlattice and Phase Coexistence inside Thin
           Film Organometal Halide Perovskite (Adv. Mater. 8/2018)
    • Authors: Tae Woong Kim; Satoshi Uchida, Tomonori Matsushita, Ludmila Cojocaru, Ryota Jono, Kohei Kimura, Daiki Matsubara, Manabu Shirai, Katsuji Ito, Hiroaki Matsumoto, Takashi Kondo, Hiroshi Segawa
      Abstract: Atomic configurations of superlattices of an organometal halide perovskite layer composed of a mixture of tetragonal and cubic phases are reported by Tae Woong Kim, Satoshi Uchida, Hiroshi Segawa, and co-workers in article number 1705230. The tetragonal and cubic phases are found to coexist at room temperature, and superlattices composed of a mixture of tetragonal and cubic phases are found to be self-organized without a compositional change. The fundamental crystallographic information of the organometal halide perovskite is shown and their new possibilities as promising materials for various applications are demonstrated.
      PubDate: 2018-02-19T06:01:48.388111-05:
      DOI: 10.1002/adma.201870053
       
  • Intelligent Albumin-MnO2 Nanoparticles as pH-/H2O2-Responsive Dissociable
           Nanocarriers to Modulate Tumor Hypoxia for Effective Combination Therapy
    • Authors: Qian Chen; Liangzhu Feng, Jingjing Liu, Wenwen Zhu, Ziliang Dong, Yifan Wu, Zhuang Liu
      PubDate: 2018-02-19T06:01:47.375474-05:
      DOI: 10.1002/adma.201707414
       
  • Solar Cells: Surpassing 10% Efficiency Benchmark for Nonfullerene Organic
           Solar Cells by Scalable Coating in Air from Single Nonhalogenated Solvent
           (Adv. Mater. 8/2018)
    • Authors: Long Ye; Yuan Xiong, Qianqian Zhang, Sunsun Li, Cheng Wang, Zhang Jiang, Jianhui Hou, Wei You, Harald Ade
      Abstract: Realizing over 10% efficiency in printed organic solar cells via scalable materials and less toxic solvents remains a grand challenge. In article number 1705485, Harald Ade and co-workers report chlorine-free, in-air blade-coating of a new photoactive combination, FTAZ:IT-M, which is able to yield an efficiency of nearly 11%, despite a high humidity of ≈50%.
      PubDate: 2018-02-19T06:01:47.230737-05:
      DOI: 10.1002/adma.201870054
       
  • Imaging Heterogeneously Distributed Photo-Active Traps in Perovskite
           Single Crystals
    • Authors: Haifeng Yuan; Elke Debroye, Eva Bladt, Gang Lu, Masoumeh Keshavarz, Kris P. F. Janssen, Maarten B. J. Roeffaers, Sara Bals, Edward H. Sargent, Johan Hofkens
      Abstract: Organic–inorganic halide perovskites (OIHPs) have demonstrated outstanding energy conversion efficiency in solar cells and light-emitting devices. In spite of intensive developments in both materials and devices, electronic traps and defects that significantly affect their device properties remain under-investigated. Particularly, it remains challenging to identify and to resolve traps individually at the nanoscopic scale. Here, photo-active traps (PATs) are mapped over OIHP nanocrystal morphology of different crystallinity by means of correlative optical differential super-resolution localization microscopy (Δ-SRLM) and electron microscopy. Stochastic and monolithic photoluminescence intermittency due to individual PATs is observed on monocrystalline and polycrystalline OIHP nanocrystals. Δ-SRLM reveals a heterogeneous PAT distribution across nanocrystals and determines the PAT density to be 1.3 × 1014 and 8 × 1013 cm−3 for polycrystalline and for monocrystalline nanocrystals, respectively. The higher PAT density in polycrystalline nanocrystals is likely related to an increased defect density. Moreover, monocrystalline nanocrystals that are prepared in an oxygen- and moisture-free environment show a similar PAT density as that prepared at ambient conditions, excluding oxygen or moisture as chief causes of PATs. Hence, it is concluded that the PATs come from inherent structural defects in the material, which suggests that the PAT density can be reduced by improving crystalline quality of the material.Optical differential super-resolution localization microscopy maps the heterogeneous distribution of photo-active traps in organic–inorganic lead halide perovskite nanocrystals by contrast of photoluminescence intermittency. The reconstructed trap distribution is correlated with the morphology and crystallinity of nanocrystals. The higher average trap density revealed in polycrystalline nanocrystals indicates that the traps are correlated with structural defects.
      PubDate: 2018-02-19T03:21:15.438497-05:
      DOI: 10.1002/adma.201705494
       
  • Single Carbon Fibers with a Macroscopic-Thickness, 3D Highly Porous Carbon
           Nanotube Coating
    • Authors: Mingchu Zou; Wenqi Zhao, Huaisheng Wu, Hui Zhang, Wenjing Xu, Liusi Yang, Shiting Wu, Yunsong Wang, Yijun Chen, Lu Xu, Anyuan Cao
      Abstract: Carbon fiber (CF) grafted with a layer of carbon nanotubes (CNTs) plays an important role in composite materials and other fields; to date, the applications of CNTs@CF multiscale fibers are severely hindered by the limited amount of CNTs grafted on individual CFs and the weak interfacial binding force. Here, monolithic CNTs@CF fibers consisting of a 3D highly porous CNT sponge layer with macroscopic-thickness (up to several millimeters), which is directly grown on a single CF, are fabricated. Mechanical tests reveal high sponge–CF interfacial strength owing to the presence of a thin transitional layer, which completely inhibits the CF slippage from the matrix upon fracture in CNTs@CF fiber–epoxy composites. The porous conductive CNTs@CF hybrid fibers also act as a template for introducing active materials (pseudopolymers and oxides), and a solid-state fiber-shaped supercapacitor and a fiber-type lithium-ion battery with high performances are demonstrated. These CNTs@CF fibers with macroscopic CNT layer thickness have many potential applications in areas such as hierarchically reinforced composites and flexible energy-storage textiles.Macroscopic CNTs@CF hybrid fibers are fabricated by directly growing a millimeter-thick 3D porous carbon nanotube sponge layer on a single carbon fiber with high interfacial strength quantified by pull-out tests, and show potential applications in reinforced nanocomposites and high-performance fiber-shaped energy devices such as supercapacitors and lithium-ion batteries.
      PubDate: 2018-02-19T03:12:33.379591-05:
      DOI: 10.1002/adma.201704419
       
  • Direct Visualization of the Reversible O2−/O− Redox Process in
           Li-Rich Cathode Materials
    • Authors: Xiang Li; Yu Qiao, Shaohua Guo, Zhenming Xu, Hong Zhu, Xiaoyu Zhang, Yang Yuan, Ping He, Masayoshi Ishida, Haoshen Zhou
      Abstract: Conventional cathodes of Li-ion batteries mainly operate through an insertion–extraction process involving transition metal redox. These cathodes will not be able to meet the increasing requirements until lithium-rich layered oxides emerge with beyond-capacity performance. Nevertheless, in-depth understanding of the evolution of crystal and excess capacity delivered by Li-rich layered oxides is insufficient. Herein, various in situ technologies such as X-ray diffraction and Raman spectroscopy are employed for a typical material Li1.2Ni0.2Mn0.6O2, directly visualizing O−O− (peroxo oxygen dimers) bonding mostly along the c-axis and demonstrating the reversible O2−/O− redox process. Additionally, the formation of the peroxo OO bond is calculated via density functional theory, and the corresponding OO bond length of ≈1.3 Å matches well with the in situ Raman results. These findings enrich the oxygen chemistry in layered oxides and open opportunities to design high-performance positive electrodes for lithium-ion batteries.A typical Li-rich material Li1.2Ni0.2Mn0.6O2 is systematically analyzed by in situ X-ray diffraction and Raman spectroscopy. Peroxo OO bonding is directly visualized mostly along the c-axis and a reversible O2−/O− redox process is demonstrated. Additionally, the formation of peroxo OO bonds is calculated via density functional theory, and the corresponding OO bond length of ≈1.3 Å matches well with the in situ Raman results.
      PubDate: 2018-02-19T03:07:28.231415-05:
      DOI: 10.1002/adma.201705197
       
  • A Simple, General Synthetic Route toward Nanoscale Transition Metal
           Borides
    • Authors: Palani R. Jothi; Kunio Yubuta, Boniface P. T. Fokwa
      Abstract: Most nanomaterials, such as transition metal carbides, phosphides, nitrides, chalcogenides, etc., have been extensively studied for their various properties in recent years. The similarly attractive transition metal borides, on the contrary, have seen little interest from the materials science community, mainly because nanomaterials are notoriously difficult to synthesize. Herein, a simple, general synthetic method toward crystalline transition metal boride nanomaterials is proposed. This new method takes advantage of the redox chemistry of Sn/SnCl2, the volatility and recrystallization of SnCl2 at the synthesis conditions, as well as the immiscibility of tin with boron, to produce crystalline phases of 3d, 4d, and 5d transition metal nanoborides with different morphologies (nanorods, nanosheets, nanoprisms, nanoplates, nanoparticles, etc.). Importantly, this method allows flexibility in the choice of the transition metal, as well as the ability to target several compositions within the same binary phase diagram (e.g., Mo2B, α-MoB, MoB2, Mo2B4). The simplicity and wide applicability of the method should enable the fulfillment of the great potential of this understudied class of materials, which show a variety of excellent chemical, electrochemical, and physical properties at the microscale.A simple, general synthetic route toward transition metal nanoborides is presented. This new method takes advantage of the redox chemistry of Sn/SnCl2 and the volatility and recrystallization of SnCl2 to produce crystalline phases of 3d, 4d, and 5d transition metal nanoborides with different morphologies (nanorods, nanosheets, nanoprisms, nanoplates, nanoparticles) for the first time.
      PubDate: 2018-02-19T03:06:43.042573-05:
      DOI: 10.1002/adma.201704181
       
  • Light-Induced Reversible Control of Ferroelectric Polarization in BiFeO3
    • Authors: Ming-Min Yang; Marin Alexe
      Abstract: Manipulation of ferroic order parameters, namely (anti-)ferromagnetic, ferroelectric, and ferroelastic, by light at room temperature is a fascinating topic in modern solid-state physics due to potential cross-fertilization in research fields that are largely decoupled. Here, full optical control, that is, reversible switching, of the ferroelectric/ferroelastic domains in BiFeO3 thin films at room temperature by the mediation of the tip-enhanced photovoltaic effect is demonstrated. The enhanced short-circuit photocurrent density at the tip contact area generates a local electric field well exceeding the coercive field, enabling ferroelectric polarization switching. Interestingly, by tailoring the photocurrent direction, via either tuning the illumination geometry or simply rotating the light polarization, full control of the ferroelectric polarization is achieved. The finding offers a new insight into the interactions between light and ferroic orders, enabling fully optical control of all the ferroic orders at room temperature and providing guidance to design novel optoferroic devices for data storage and sensing.Full optical control of ferroelectric order parameters at room temperature is demonstrated by a combination of the bulk photovoltaic effect and the tip of an atomic force microscope. The ferroelectric polarization of a BiFeO3 thin film can be reversibly switched solely by light via changing illumination areas or simply rotating the light polarization angles.
      PubDate: 2018-02-19T03:06:12.527558-05:
      DOI: 10.1002/adma.201704908
       
  • Zwitterionic Nanocages Overcome the Efficacy Loss of Biologic Drugs
    • Authors: Bowen Li; Zhefan Yuan, Peng Zhang, Andrew Sinclair, Priyesh Jain, Kan Wu, Caroline Tsao, Jingyi Xie, Hsiang-Chieh Hung, Xiaojie Lin, Tao Bai, Shaoyi Jiang
      Abstract: For biotherapeutics that require multiple administrations to fully cure diseases, the induction of undesirable immune response is one common cause for the failure of their treatment. Covalent binding of hydrophilic polymers to proteins is commonly employed to mitigate potential immune responses. However, while this technique is proved to partially reduce the antibodies (Abs) reactive to proteins, it may induce Abs toward their associated polymers and thus result in the loss of efficacy. Zwitterionic poly(carboxybetaine) (PCB) is recently shown to improve the immunologic properties of proteins without inducing any antipolymer Abs against itself. However, it is unclear if the improved immunologic profiles can translate to better clinical outcomes since improved immunogenicity cannot directly reflect amelioration in efficacy. Here, a PCB nanocage (PCB NC) is developed, which can physically encase proteins while keeping their structure intact. PCB NC encapsulation of uricase, a highly immunogenic enzyme, is demonstrated to eradicate all the immune responses. To bridge the gap between immunogenicity and efficacy studies, the therapeutic performance of PCB NC uricase is evaluated and compared with its PEGylated counterpart in a clinical-mimicking gouty rat model to determine any loss of efficacy evoked after five administrations.A zwitterionic poly(carboxybetaine) (PCB) nanocage (PCB NC) is developed to physically encase proteins while keeping their structure intact. PCB NC encapsulation of uricase is manifested to eliminate all the possible immune responses. A high therapeutic performance of PCB-NC-shrouded uricase is demonstrated in a gouty rat model without evoking efficacy loss even after five repetitive administrations, greatly outperforming the industry-standard PEGylated counterpart.
      PubDate: 2018-02-19T03:05:57.231368-05:
      DOI: 10.1002/adma.201705728
       
  • Vitrimer Elastomer-Based Jigsaw Puzzle-Like Healable Triboelectric
           Nanogenerator for Self-Powered Wearable Electronics
    • Authors: Jianan Deng; Xiao Kuang, Ruiyuan Liu, Wenbo Ding, Aurelia C. Wang, Ying-Chih Lai, Kai Dong, Zhen Wen, Yaxian Wang, Lili Wang, H. Jerry Qi, Tong Zhang, Zhong Lin Wang
      Abstract: Functional polymers possess outstanding uniqueness in fabricating intelligent devices such as sensors and actuators, but they are rarely used for converting mechanical energy into electric power. Here, a vitrimer based triboelectric nanogenerator (VTENG) is developed by embedding a layer of silver nanowire percolation network in a dynamic disulfide bond-based vitrimer elastomer. In virtue of covalent dynamic disulfide bonds in the elastomer matrix, a thermal stimulus enables in situ healing if broken, on demand reconfiguration of shape, and assembly of more sophisticated structures of VTENG devices. On rupture or external damage, the structural integrity and conductivity of VTENG are restored under rapid thermal stimulus. The flexible and stretchable VTENG can be scaled up akin to jigsaw puzzles and transformed from 2D to 3D structures. It is demonstrated that this self-healable and shape-adaptive VTENG can be utilized for mechanical energy harvesters and self-powered tactile/pressure sensors with extended lifetime and excellent design flexibility. These results show that the incorporation of organic materials into electronic devices can not only bestow functional properties but also provide new routes for flexible device fabrication.A flexible and self-healable triboelectric nanogenerator (TENG) is achieved by combining a vitrimer elastomer and a silver nanowire network. By introducing terrace structure, scaling up TENGs can be as easy as playing jigsaw puzzles, which also provides a new fabrication route for flexible devices. The output performance also increases correspondingly when the number of assembly pieces is increased.
      PubDate: 2018-02-19T03:02:38.260751-05:
      DOI: 10.1002/adma.201705918
       
  • Dual-Peak Absorbing Semiconducting Copolymer Nanoparticles for First and
           Second Near-Infrared Window Photothermal Therapy: A Comparative Study
    • Authors: Yuyan Jiang; Jingchao Li, Xu Zhen, Chen Xie, Kanyi Pu
      Abstract: Near-infrared (NIR) light is widely used for noninvasive optical diagnosis and phototherapy. However, current research focuses on the first NIR window (NIR-I, 650–950 nm), while the second NIR window (NIR-II, 1000–1700 nm) is far less exploited. The development of the first organic photothermal nanoagent (SPNI-II) with dual-peak absorption in both NIR windows and its utilization in photothermal therapy (PTT) are reported herein. Such a nanoagent comprises a semiconducting copolymer with two distinct segments that respectively and identically absorb NIR light at 808 and 1064 nm. With the photothermal conversion efficiency of 43.4% at 1064 nm generally higher than other inorganic nanomaterials, SPNI-II enables superior deep-tissue heating at 1064 nm over that at 808 nm at their respective safety limits. Model deep-tissue cancer PTT at a tissue depth of 5 mm validates the enhanced antitumor effect of SPNI-II when shifting laser irradiation from the NIR-I to the NIR-II window. The good biodistribution and facile synthesis of SPNI-II also allow it to be doped with an NIR dye for fluorescence-imaging-guided NIR-II PTT through systemic administration. Thus, this study paves the way for the development of new polymeric nanomaterials to advance phototherapy.The first dual-peak absorbing organic nanoagent with nearly identical absorbance at 808 and 1064 nm is developed from a semiconducting copolymer. Such a nanoagent not only enables deep-tissue photothermal cancer therapy in both the first and second near-infrared windows, but also permits a fair comparative study to reveal the advantage of shifting the laser light into a longer wavelength region for phototherapy.
      PubDate: 2018-02-19T03:01:47.542679-05:
      DOI: 10.1002/adma.201705980
       
  • Noninvasively Modifying Band Structures of Wide-Bandgap Metal Oxides to
           Boost Photocatalytic Activity
    • Authors: Zongbao Yu; Xing-Qiu Chen, Xiangdong Kang, Yingpeng Xie, Huaze Zhu, Shoulong Wang, Sami Ullah, Hui Ma, Lianzhou Wang, Gang Liu, Xiuliang Ma, Hui-Ming Cheng
      Abstract: Although doping with appropriate heteroatoms is a powerful way of increasing visible light absorption of wide-bandgap metal oxide photocatalysts, the incorporation of heteroatoms into the photocatalysts usually leads to the increase of deleterious recombination centers of photogenerated charge carriers. Here, a conceptual strategy of increasing visible light absorption without causing additional recombination centers by constructing an ultrathin insulating heterolayer of amorphous boron oxynitride on wide-bandgap photocatalysts is shown. The nature of this strategy is that the active composition nitrogen in the heterolayer can noninvasively modify the electronic structure of metal oxides for visible light absorption through the interface contact between the heterolayer and metal oxides. The photocatalysts developed show significant improvements in photocatalytic activity under both UV–vis and visible light irradiation compared to the doped counterparts by conventional doping process. These results may provide opportunities for flexibly tailoring the electronic structure of metal oxides.A conceptual strategy of increasing visible light absorption without increasing recombination centers by constructing an ultrathin insulating heterolayer of amorphous boron oxynitride on wide-bandgap photocatalysts is developed to boost photocatalytic activity. The nature of this strategy is that the active composition nitrogen in the heterolayer can noninvasively modify the electronic structure of metal oxides for visible light absorption.
      PubDate: 2018-02-19T03:01:18.346773-05:
      DOI: 10.1002/adma.201706259
       
  • In Situ Repair of 2D Chalcogenides under Electron Beam Irradiation
    • Authors: Yuting Shen; Tao Xu, Xiaodong Tan, Longbing He, Kuibo Yin, Neng Wan, Litao Sun
      Abstract: Molybdenum disulfide (MoS2) and bismuth telluride (Bi2Te3) are the two most common types of structures adopted by 2D chalcogenides. In view of their unique physical properties and structure, 2D chalcogenides have potential applications in various fields. However, the excellent properties of these 2D crystals depend critically on their crystal structures, where defects, cracks, holes, or even greater damage can be inevitably introduced during the preparation and transferring processes. Such defects adversely impact the performance of devices made from 2D chalcogenides and, hence, it is important to develop ways to intuitively and precisely repair these 2D crystals on the atomic scale, so as to realize high-reliability devices from these structures. Here, an in situ study of the repair of the nanopores in MoS2 and Bi2Te3 is carried out under electron beam irradiation by transmission electron microscopy. The experimental conditions allow visualization of the structural dynamics of MoS2 and Bi2Te3 crystals with unprecedented resolution. Real-time observation of the healing of defects at atomic resolution can potentially help to reproducibly fabricate and simultaneously image single-crystalline free-standing 2D chalcogenides. Thus, these findings demonstrate the viability of using an electron beam as an effective tool to precisely engineer materials to suit desired applications in the future.Controlled electron beam irradiation can be utilized as a tool to repair the nanopores in MoS2 and Bi2Te3 and lead to high-quality crystals with a low number of defects. The dynamic repair processes yield an in-depth understanding of the repair mechanism in 2D chalcogenides: the sites with more surrounding atom columns have higher priority to be occupied by adatoms.
      PubDate: 2018-02-16T03:03:17.935829-05:
      DOI: 10.1002/adma.201705954
       
  • Looking into the Future: Toward Advanced 3D Biomaterials for
           Stem-Cell-Based Regenerative Medicine
    • Authors: Zhongmin Liu; Mingliang Tang, Jinping Zhao, Renjie Chai, Jiuhong Kang
      Abstract: Stem-cell-based therapies have the potential to provide novel solutions for the treatment of a variety of diseases, but the main obstacles to such therapies lie in the uncontrolled differentiation and functional engraftment of implanted tissues. The physicochemical microenvironment controls the self-renewal and differentiation of stem cells, and the key step in mimicking the stem cell microenvironment is to construct a more physiologically relevant 3D culture system. Material-based 3D assemblies of stem cells facilitate the cellular interactions that promote morphogenesis and tissue organization in a similar manner to that which occurs during embryogenesis. Both natural and artificial materials can be used to create 3D scaffolds, and synthetic organic and inorganic porous materials are the two main kinds of artificial materials. Nanotechnology provides new opportunities to design novel advanced materials with special physicochemical properties for 3D stem cell culture and transplantation. Herein, the advances and advantages of 3D scaffold materials, especially with respect to stem-cell-based therapies, are first outlined. Second, the stem cell biology in 3D scaffold materials is reviewed. Third, the progress and basic principles of developing 3D scaffold materials for clinical applications in tissue engineering and regenerative medicine are reviewed.Stem-cell-based therapies have the potential to treat various diseases. A main obstacle, however, is the uncontrolled differentiation of implanted stem cells. Material-based 3D assemblies of stem cells facilitate cellular interactions that are similar to those during embryogenesis. The progress and basic principles of developing 3D scaffold materials toward regenerative medicine and their advances for stem cells are reviewed.
      PubDate: 2018-02-16T02:21:20.273568-05:
      DOI: 10.1002/adma.201705388
       
  • Nanoalloy Materials for Chemical Catalysis
    • Authors: Hao Fang; Jinhu Yang, Ming Wen, Qingsheng Wu
      Abstract: Nanoalloys (NAs), which are distinctly different from bulk alloys or single metals, take on intrinsic features including tunable components and ratios, variable constructions, reconfigurable electronic structures, and optimizable performances, which endow NAs with fascinating prospects in the catalysis field. Here, the focus is on NA materials for chemical catalysis (except photocatalysis or electrocatalysis). In terms of composition, NA systems are divided into three groups, noble metal, base metal, and noble/base metal mixed NAs. Their design and fabrication for the optimization of catalytic performance are systematically summarized. Additionally, the correlations between the composition/structure and catalytic properties are also mentioned. Lastly, the challenges faced in current research are discussed, and further pathways toward their development are suggested.Synthesis approaches and catalytic reactions of three groups of nanoalloys, including noble metals, base metals, and noble/base metals, are summarized systematically, and the correlations between composition/structure and catalytic performance are discussed. The existing challenges and developing orientations are also mentioned.
      PubDate: 2018-02-16T02:13:36.020801-05:
      DOI: 10.1002/adma.201705698
       
  • Polymer Vesicles: Modular Platforms for Cancer Theranostics
    • Authors: Fangyingkai Wang; Jiangang Xiao, Shuai Chen, Hui Sun, Bo Yang, Jinhui Jiang, Xue Zhou, Jianzhong Du
      Abstract: As an emerging field that is receiving an increasing amount of interest, theranostics is becoming increasingly important in the field of nanomedicine. Among the various smart platforms that have been proposed for use in theranostics, polymer vesicles (or polymersomes) are among the most promising candidates for integration of designated functionalities and modalities. Here, a brief summary of typical theranostic platforms is presented with a focus on modular polymer vesicles. To highlight modularity, the different methodologies for designing therapeutic and diagnostic modules are classified and current examples of theranostic vesicles that excel in both performance and design principle are provided. Finally, future prospects for theranostic polymer vesicles that can be readily prepared with functional modules are proposed. Overall, theranostic polymer vesicles with modular modalities and functions are more promising in nanomedicine than simply being “over-engineered”.Theranostic polymer vesicles have been developed to achieve imaging and therapeutic effects in one system. Such systems are reviewed: they are decomposed to the level of therapeutic modules and imaging modules to summarize the methodologies for the construction of such modular platforms.
      PubDate: 2018-02-16T02:12:27.686986-05:
      DOI: 10.1002/adma.201705674
       
  • Graphene and Carbon-Nanotube Nanohybrids Covalently Functionalized by
           Porphyrins and Phthalocyanines for Optoelectronic Properties
    • Authors: Aijian Wang; Jun Ye, Mark G. Humphrey, Chi Zhang
      Abstract: In recent years, there has been a rapid growth in studies of the optoelectronic properties of graphene, carbon nanotubes (CNTs), and their derivatives. The chemical functionalization of graphene and CNTs is a key requirement for the development of this field, but it remains a significant challenge. The focus here is on recent advances in constructing nanohybrids of graphene or CNTs covalently linked to porphyrins or phthalocyanines, as well as their application in nonlinear optics. Following a summary of the syntheses of nanohybrids constructed from graphene or CNTs and porphyrins or phthalocyanines, explicit intraconjugate electronic interactions between photoexcited porphyrins/phthalocyanines and graphene/CNTs are introduced classified by energy transfer, electron transfer, and charge transfer, and their optoelectronic applications are also highlighted. The major current challenges for the development of covalently linked nanohybrids of porphyrins or phthalocyanines and carbon nanostructures are also presented.Studies of the optoelectronic properties of graphene, carbon nanotubes (CNTs), and their derivatives have grown rapidly in recent years. The recent advances in constructing nanohybrids of graphene or CNTs covalently linked to porphyrins or phthalocyanines, as well as their applications in nonlinear optics, are reviewed, and their explicit intraconjugate electronic interactions, and future directions are discussed.
      PubDate: 2018-02-16T02:10:48.461995-05:
      DOI: 10.1002/adma.201705704
       
  • Conjugated Polyelectrolytes Bearing Various Ion Densities: Spontaneous
           Dipole Generation, Poling-Induced Dipole Alignment, and Interfacial Energy
           Barrier Control for Optoelectronic Device Applications
    • Authors: Seungjin Lee; Thanh Luan Nguyen, Sang Yun Lee, Chung Hyeon Jang, Bo Ram Lee, Eui Dae Jung, Song Yi Park, Yung Jin Yoon, Jin Young Kim, Han Young Woo, Myoung Hoon Song
      Abstract: Conjugated polyelectrolytes (CPEs) with π-delocalized main backbones and ionic pendant groups are intensively studied as interfacial layers for efficient polymer-based optoelectronic devices (POEDs) because they facilitate facile control of charge injection/extraction barriers. Here, a simple and effective method of performing precise interfacial energy level adjustment is presented by employing CPEs with different thicknesses and various ion densities under electric poling to realize efficient charge injection/extraction of POEDs. The effects of the CPE ion densities and electric (positive or negative) poling on the energy level tuning process are investigated by measuring the open-circuit voltages and current densities of devices with the structure indium tin oxide/zinc oxide/CPE/organic active layer/molybdenum oxide/gold while changing the CPE film thickness. The performances of inverted polymer light-emitting diodes and inverted polymer solar cells are remarkably improved by precisely controlling the interfacial energy level matching using optimum CPE conditions.The fine modulation of ion-group distributions in conjugated polyelectrolyte (CPE) layers, interfacial dipoles, and the resulting interfacial energy level alignment via spontaneous polarization and electric poling are studied using a series of CPEs with different ion densities.
      PubDate: 2018-02-16T02:06:26.964203-05:
      DOI: 10.1002/adma.201706034
       
  • 3D NIR-II Molecular Imaging Distinguishes Targeted Organs with
           High-Performance NIR-II Bioconjugates
    • Authors: Shoujun Zhu; Sonia Herraiz, Jingying Yue, Mingxi Zhang, Hao Wan, Qinglai Yang, Zhuoran Ma, Yan Wang, Jiahuan He, Alexander L. Antaris, Yeteng Zhong, Shuo Diao, Yi Feng, Ying Zhou, Kuai Yu, Guosong Hong, Yongye Liang, Aaron J. Hsueh, Hongjie Dai
      Abstract: Greatly reduced scattering in the second near-infrared (NIR-II) region (1000–1700 nm) opens up many new exciting avenues of bioimaging research, yet NIR-II fluorescence imaging is mostly implemented by using nontargeted fluorophores or wide-field imaging setups, limiting the signal-to-background ratio and imaging penetration depth due to poor specific binding and out-of-focus signals. A newly developed high-performance NIR-II bioconjugate enables targeted imaging of a specific organ in the living body with high quality. Combined with a home-built NIR-II confocal set-up, the enhanced imaging technique allows 900 µm-deep 3D organ imaging without tissue clearing techniques. Bioconjugation of two hormones to nonoverlapping NIR-II fluorophores facilitates two-color imaging of different receptors, demonstrating unprecedented multicolor live molecular imaging across the NIR-II window. This deep tissue imaging of specific receptors in live animals allows development of noninvasive molecular imaging of multifarious models of normal and neoplastic organs in vivo, beyond the traditional visible to NIR-I range. The developed NIR-II fluorescence microscopy will become a powerful imaging technique for deep tissue imaging without any physical sectioning or clearing treatment of the tissue.Two-color live molecular imaging across the second near-infrared (NIR-II) window (1000–1700 nm) is achieved by high-performance NIR-II bioconjugates. A great 900 µm scanning depth is achieved by NIR-II one-photon confocal 3D molecular imaging and provides a new solution for simultaneously visualizing tissue structure and allowing molecular phenotyping in a large tissue volume.
      PubDate: 2018-02-15T03:18:25.671544-05:
      DOI: 10.1002/adma.201705799
       
  • Advancements and Challenges in Multidomain Multicargo Delivery Vehicles
    • Authors: Eugenia Pugliese; João Q. Coentro, Dimitrios I. Zeugolis
      Abstract: Reparative and regenerative processes are well-orchestrated temporal and spatial events that are governed by multiple cells, molecules, signaling pathways, and interactions thereof. Yet again, currently available implantable devices fail largely to recapitulate nature's complexity and sophistication in this regard. Herein, success stories and challenges in the field of layer-by-layer, composite, self-assembly, and core–shell technologies are discussed for the development of multidomain/multicargo delivery vehicles.Reparative and regenerative processes are well-orchestrated temporal and spatial events that are governed by multiple cells, molecules, signaling pathways, and interactions thereof. Currently available single-cargo-delivery vehicles fail to recapitulate nature's complexity and sophistication. Advancements and challenges in the field of layer-by-layer, self-assembly, composite, and core–shell technologies are discussed for the development of multidomain/multicargo delivery vehicles.
      PubDate: 2018-02-15T03:17:11.08575-05:0
      DOI: 10.1002/adma.201704324
       
  • Synthetic Transient Crosslinks Program the Mechanics of Soft,
           Biopolymer-Based Materials
    • Authors: Jessica S. Lorenz; Jörg Schnauß, Martin Glaser, Martin Sajfutdinow, Carsten Schuldt, Josef A. Käs, David M. Smith
      Abstract: Actin networks are adaptive materials enabling dynamic and static functions of living cells. A central element for tuning their underlying structural and mechanical properties is the ability to reversibly connect, i.e., transiently crosslink, filaments within the networks. Natural crosslinkers, however, vary across many parameters. Therefore, systematically studying the impact of their fundamental properties like size and binding strength is unfeasible since their structural parameters cannot be independently tuned. Herein, this problem is circumvented by employing a modular strategy to construct purely synthetic actin crosslinkers from DNA and peptides. These crosslinkers mimic both intuitive and noncanonical mechanical properties of their natural counterparts. By isolating binding affinity as the primary control parameter, effects on structural and dynamic behaviors of actin networks are characterized. A concentration-dependent triphasic behavior arises from both strong and weak crosslinkers due to emergent structural polymorphism. Beyond a certain threshold, strong binding leads to a nonmonotonic elastic pulse, which is a consequence of self-destruction of the mechanical structure of the underlying network. The modular design also facilitates an orthogonal regulatory mechanism based on enzymatic cleaving. This approach can be used to guide the rational design of further biomimetic components for programmable modulation of the properties of biomaterials and cells.Biomimetic crosslinking constructs for actin networks are prepared from synthetic materials, by chemically conjugating polypeptide-based binding domains onto double-stranded DNA scaffolds. The resulting biohybrid networks display mechanical and morphological features remarkably similar to their biologically derived counterparts. The DNA-based design enables a modular approach, where structural parameters and functional features, such as an enzymatic regulatory mechanism, can be directly integrated.
      PubDate: 2018-02-15T02:00:03.226878-05:
      DOI: 10.1002/adma.201706092
       
  • Small-Scale Machines Driven by External Power Sources
    • Authors: Xiang-Zhong Chen; Bumjin Jang, Daniel Ahmed, Chengzhi Hu, Carmela De Marco, Marcus Hoop, Fajer Mushtaq, Bradley J. Nelson, Salvador Pané
      Abstract: Micro- and nanorobots have shown great potential for applications in various fields, including minimally invasive surgery, targeted therapy, cell manipulation, environmental monitoring, and water remediation. Recent progress in the design, fabrication, and operation of these miniaturized devices has greatly enhanced their versatility. In this report, the most recent progress on the manipulation of small-scale robots based on power sources, such as magnetic fields, light, acoustic waves, electric fields, thermal energy, or combinations of these, is surveyed. The design and propulsion mechanism of micro- and nanorobots are the focus of this article. Their fabrication and applications are also briefly discussed.Externally powered micro- and nanorobots are promising candidates for future biomedical applications. In this Progress Report, recent progress on externally powered small-scale robots is summarized based on their power sources. The emphasis is laid on the design and propulsion mechanism of the microrobots. The fabrication and application is briefly discussed as well.
      PubDate: 2018-02-14T09:37:32.712191-05:
      DOI: 10.1002/adma.201705061
       
  • A Thermally Insulating Textile Inspired by Polar Bear Hair
    • Authors: Ying Cui; Huaxin Gong, Yujie Wang, Dewen Li, Hao Bai
      Abstract: Animals living in the extremely cold environment, such as polar bears, have shown amazing capability to keep warm, benefiting from their hollow hairs. Mimicking such a strategy in synthetic fibers would stimulate smart textiles for efficient personal thermal management, which plays an important role in preventing heat loss and improving efficiency in house warming energy consumption. Here, a “freeze-spinning” technique is used to realize continuous and large-scale fabrication of fibers with aligned porous structure, mimicking polar bear hairs, which is difficult to achieve by other methods. A textile woven with such biomimetic fibers shows an excellent thermal insulation property as well as good breathability and wearability. In addition to passively insulating heat loss, the textile can also function as a wearable heater, when doped with electroheating materials such as carbon nanotubes, to induce fast thermal response and uniform electroheating while maintaining its soft and porous nature for comfortable wearing.A textile with excellent thermal insulation capability, mimicking the porous structure of polar bear hair, is fabricated by a “freeze-spinning” technique to continuously spin silk fibroin solution into aligned porous fibers. Doped with electroheating materials, this type of textile is beneficial for personal thermal management, thermal stealth in military applications, and wearable electronics.
      PubDate: 2018-02-14T09:31:07.267544-05:
      DOI: 10.1002/adma.201706807
       
  • Heterogeneous Single-Atom Catalyst for Visible-Light-Driven High-Turnover
           CO2 Reduction: The Role of Electron Transfer
    • Authors: Chao Gao; Shuangming Chen, Ying Wang, Jiawen Wang, Xusheng Zheng, Junfa Zhu, Li Song, Wenkai Zhang, Yujie Xiong
      Abstract: Visible-light-driven conversion of CO2 into chemical fuels is an intriguing approach to address the energy and environmental challenges. In principle, light harvesting and catalytic reactions can be both optimized by combining the merits of homogeneous and heterogeneous photocatalysts; however, the efficiency of charge transfer between light absorbers and catalytic sites is often too low to limit the overall photocatalytic performance. In this communication, it is reported that the single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. As a result, the turnover number for CO production reaches a high value of 678 with an unprecedented turnover frequency of 3.77 min−1, superior to those obtained with the state-of-the-art heterogeneous photocatalysts. This work provides fresh insights into the design of catalytic sites toward photocatalytic CO2 conversion from the angle of single-atom catalysis and highlights the role of charge kinetics in bridging the gap between heterogeneous and homogeneous photocatalysts.The single-atom Co sites coordinated on the partially oxidized graphene nanosheets can serve as a highly active and durable heterogeneous catalyst for CO2 conversion, wherein the graphene bridges homogeneous light absorbers with single-atom catalytic sites for the efficient transfer of photoexcited electrons. This design enables a turnover frequency of 3.77 min−1, superior to those obtained with conventional heterogeneous photocatalysts.
      PubDate: 2018-02-14T02:34:48.343088-05:
      DOI: 10.1002/adma.201704624
       
  • Flourishing Bioinspired Antifogging Materials with Superwettability:
           Progresses and Challenges
    • Authors: Zhiwu Han; Xiaoming Feng, Zhiguang Guo, Shichao Niu, Luquan Ren
      Abstract: Antifogging (AF) structure materials found in nature have great potential for enabling novel and emerging products and technologies to facilitate the daily life of human societies, attracting enormous research interests owing to their potential applications in display devices, traffics, agricultural greenhouse, food packaging, solar products, and other fields. The outstanding performance of biological AF surfaces encourages the rapid development and wide application of new AF materials. In fact, AF properties are inextricably associated with their surface superwettability. Generally, the superwettability of AF materials depends on a combination of their surface geometrical structures and surface chemical compositions. To explore their general design principles, recent progresses in the investigation of bioinspired AF materials are summarized herein. Recent developments of the mechanism, fabrication, and applications of bioinspired AF materials with superwettability are also a focus. This includes information on constructing superwetting AF materials based on designing the topographical structure and regulating the surface chemical composition. Finally, the remaining challenges and promising breakthroughs in this field are also briefly discussed.Bioinspired antifogging materials with superwettability have great potential for inspiring novel products and technologies to facilitate human life, such as in eyeglasses, traffics, solar products, and so on. The outstanding performance of biological antifogging surfaces encourages the rapid development and wide application of new antifogging materials. Herein, the mechanism, fabrication, progresses, challenges, and perspectives of this material are reviewed.
      PubDate: 2018-02-14T02:32:11.588051-05:
      DOI: 10.1002/adma.201704652
       
  • Biodegradable Spheres Protect Traumatically Injured Spinal Cord by
           Alleviating the Glutamate-Induced Excitotoxicity
    • Authors: Dongfei Liu; Jian Chen, Tao Jiang, Wei Li, Yao Huang, Xiyi Lu, Zehua Liu, Weixia Zhang, Zheng Zhou, Qirui Ding, Hélder A. Santos, Guoyong Yin, Jin Fan
      Abstract: New treatment strategies for spinal cord injury with good therapeutic efficacy are actively pursued. Here, acetalated dextran (AcDX), a biodegradable polymer obtained by modifying vicinal diols of dextran, is demonstrated to protect the traumatically injured spinal cord. To facilitate its administration, AcDX is formulated into microspheres (≈7.2 µm in diameter) by the droplet microfluidic technique. Intrathecally injected AcDX microspheres effectively reduce the traumatic lesion volume and inflammatory response in the injured spinal cord, protect the spinal cord neurons from apoptosis, and ultimately, recover the locomotor function of injured rats. The neuroprotective feature of AcDX microspheres is achieved by sequestering glutamate and calcium ions in cerebrospinal fluid. The scavenging of glutamate and calcium ion reduces the influx of calcium ions into neurons and inhibits the formation of reactive oxygen species. Consequently, AcDX microspheres attenuate the expression of proapoptotic proteins, Calpain, and Bax, and enhance the expression of antiapoptotic protein Bcl-2. Overall, AcDX microspheres protect traumatically injured spinal cord by alleviating the glutamate-induced excitotoxicity. This study opens an exciting perspective toward the application of neuroprotective AcDX for the treatment of severe neurological diseases.Intrathecally administrated acetalated dextran microspheres scavenge the glutamate and calcium ions in cerebrospinal fluid, attenuate glutamate-induced excitotoxicity, and ultimately protect injured spinal cord neurons in rats.
      PubDate: 2018-02-14T02:30:49.232972-05:
      DOI: 10.1002/adma.201706032
       
  • Strategic Advances in Formation of Cell-in-Shell Structures: From
           Syntheses to Applications
    • Authors: Beom Jin Kim; Hyeoncheol Cho, Ji Hun Park, João F. Mano, Insung S. Choi
      Abstract: Single-cell nanoencapsulation, forming cell-in-shell structures, provides chemical tools for endowing living cells, in a programmed fashion, with exogenous properties that are neither innate nor naturally achievable, such as cascade organic-catalysis, UV filtration, immunogenic shielding, and enhanced tolerance in vitro against lethal factors in real-life settings. Recent advances in the field make it possible to further fine-tune the physicochemical properties of the artificial shells encasing individual living cells, including on-demand degradability and reconfigurability. Many different materials, other than polyelectrolytes, have been utilized as a cell-coating material with proper choice of synthetic strategies to broaden the potential applications of cell-in-shell structures to whole-cell catalysis and sensors, cell therapy, tissue engineering, probiotics packaging, and others. In addition to the conventional “one-time-only” chemical formation of cytoprotective, durable shells, an approach of autonomous, dynamic shellation has also recently been attempted to mimic the naturally occurring sporulation process and to make the artificial shell actively responsive and dynamic. Here, the recent development of synthetic strategies for formation of cell-in-shell structures along with the advanced shell properties acquired is reviewed. Demonstrated applications, such as whole-cell biocatalysis and cell therapy, are discussed, followed by perspectives on the field of single-cell nanoencapsulation.Single-cell nanoencapsulation offers a chemical tool for enhancing cell viability in vitro against harmful stresses, promising potential in many applications including biocatalysis and cell therapy. Recent advances in synthetic strategies for forming cell-in-shell structures with unprecedented shell properties are discussed along with demonstrated applications.
      PubDate: 2018-02-14T02:22:36.496065-05:
      DOI: 10.1002/adma.201706063
       
  • Plasma-Assisted Synthesis and Surface Modification of Electrode Materials
           for Renewable Energy
    • Authors: Shuo Dou; Li Tao, Ruilun Wang, Samir El Hankari, Ru Chen, Shuangyin Wang
      Abstract: Renewable energy technology has been considered as a “MUST” option to lower the use of fossil fuels for industry and daily life. Designing critical and sophisticated materials is of great importance in order to realize high-performance energy technology. Typically, efficient synthesis and soft surface modification of nanomaterials are important for energy technology. Therefore, there are increasing demands on the rational design of efficient electrocatalysts or electrode materials, which are the key for scalable and practical electrochemical energy devices. Nevertheless, the development of versatile and cheap strategies is one of the main challenges to achieve the aforementioned goals. Accordingly, plasma technology has recently appeared as an extremely promising alternative for the synthesis and surface modification of nanomaterials for electrochemical devices. Here, the recent progress on the development of nonthermal plasma technology is highlighted for the synthesis and surface modification of advanced electrode materials for renewable energy technology including electrocatalysts for fuel cells, water splitting, metal–air batteries, and electrode materials for batteries and supercapacitors, etc.Designing critical and sophisticated electrode materials is of great importance to realize high-performance renewable energy technology, such as fuel cells, water-splitting devices, metal–air batteries, Li–ion batteries, and supercapacitors, etc. The recent progress in the development of nonthermal plasma technology for the synthesis and surface modification of advanced nanomaterials for electrochemical devices is highlighted.
      PubDate: 2018-02-14T02:17:07.072914-05:
      DOI: 10.1002/adma.201705850
       
  • Rational Design of Multifunctional Fe@γ-Fe2O3@H-TiO2 Nanocomposites with
           Enhanced Magnetic and Photoconversion Effects for Wide Applications: From
           Photocatalysis to Imaging-Guided Photothermal Cancer Therapy
    • Authors: Meifang Wang; Kerong Deng, Wei Lü, Xiaoran Deng, Kai Li, Yanshu Shi, Binbin Ding, Ziyong Cheng, Bengang Xing, Gang Han, Zhiyao Hou, Jun Lin
      Abstract: Titanium dioxide (TiO2) has been widely investigated and used in many areas due to its high refractive index and ultraviolet light absorption, but the lack of absorption in the visible–near infrared (Vis–NIR) region limits its application. Herein, multifunctional Fe@γ-Fe2O3@H-TiO2 nanocomposites (NCs) with multilayer-structure are synthesized by one-step hydrogen reduction, which show remarkably improved magnetic and photoconversion effects as a promising generalists for photocatalysis, bioimaging, and photothermal therapy (PTT). Hydrogenation is used to turn white TiO2 in to hydrogenated TiO2 (H-TiO2), thus improving the absorption in the Vis–NIR region. Based on the excellent solar-driven photocatalytic activities of the H-TiO2 shell, the Fe@γ-Fe2O3 magnetic core is introduced to make it convenient for separating and recovering the catalytic agents. More importantly, Fe@γ-Fe2O3@H-TiO2 NCs show enhanced photothermal conversion efficiency due to more circuit loops for electron transitions between H-TiO2 and γ-Fe2O3, and the electronic structures of Fe@γ-Fe2O3@H-TiO2 NCs are calculated using the Vienna ab initio simulation package based on the density functional theory to account for the results. The reported core–shell NCs can serve as an NIR-responsive photothermal agent for magnetic-targeted photothermal therapy and as a multimodal imaging probe for cancer including infrared photothermal imaging, magnetic resonance imaging, and photoacoustic imaging.Multilayer core–shell structured Fe@γ-Fe2O3@H-TiO2 nanocomposites (NCs) with full spectrum absorption in ultraviolet–visible–near infrared region and strong magnetic property exhibit great enhancement in photocatalytic activities and photothermal conversion efficiency. Benefiting from these outstanding properties, the NCs could be served as a promising generalist for solar-driven photocatalysis with magnetic separation property as well as magnetic-targeted and imaging-guided photothermal cancer therapy.
      PubDate: 2018-02-14T02:13:07.682167-05:
      DOI: 10.1002/adma.201706747
       
  • Amide-Catalyzed Phase-Selective Crystallization Reduces Defect Density in
           Wide-Bandgap Perovskites
    • Authors: Junghwan Kim; Makhsud I. Saidaminov, Hairen Tan, Yicheng Zhao, Younghoon Kim, Jongmin Choi, Jea Woong Jo, James Fan, Rafael Quintero-Bermudez, Zhenyu Yang, Li Na Quan, Mingyang Wei, Oleksandr Voznyy, Edward H. Sargent
      Abstract: Wide-bandgap (WBG) formamidinium–cesium (FA-Cs) lead iodide–bromide mixed perovskites are promising materials for front cells well-matched with crystalline silicon to form tandem solar cells. They offer avenues to augment the performance of widely deployed commercial solar cells. However, phase instability, high open-circuit voltage (Voc) deficit, and large hysteresis limit this otherwise promising technology. Here, by controlling the crystallization of FA-Cs WBG perovskite with the aid of a formamide cosolvent, light-induced phase segregation and hysteresis in perovskite solar cells are suppressed. The highly polar solvent additive formamide induces direct formation of the black perovskite phase, bypassing the yellow phases, thereby reducing the density of defects in films. As a result, the optimized WBG perovskite solar cells (PSCs) (Eg ≈ 1.75 eV) exhibit a high Voc of 1.23 V, reduced hysteresis, and a power conversion efficiency (PCE) of 17.8%. A PCE of 15.2% on 1.1 cm2 solar cells, the highest among the reported efficiencies for large-area PSCs having this bandgap is also demonstrated. These perovskites show excellent phase stability and thermal stability, as well as long-term air stability. They maintain ≈95% of their initial PCE after 1300 h of storage in dry air without encapsulation.The highly polar solvent additive, formamide, enables phase-selective crystallization in wide-bandgap (WBG) perovskites. By suppressing the formation of non-perovskite phases, the WBG perovskites (Eg ≈ 1.75 eV) exhibited excellent light-induced phase-, thermal, and air stability, as well as device performance with a high Voc of 1.23 V and reduced hysteresis, with a power conversion efficiency (PCE) of 17.8%.
      PubDate: 2018-02-14T02:12:28.886599-05:
      DOI: 10.1002/adma.201706275
       
  • When 2D Materials Meet Molecules: Opportunities and Challenges of Hybrid
           Organic/Inorganic van der Waals Heterostructures
    • Authors: Marco Gobbi; Emanuele Orgiu, Paolo Samorì
      Abstract: van der Waals heterostructures, composed of vertically stacked inorganic 2D materials, represent an ideal platform to demonstrate novel device architectures and to fabricate on-demand materials. The incorporation of organic molecules within these systems holds an immense potential, since, while nature offers a finite number of 2D materials, an almost unlimited variety of molecules can be designed and synthesized with predictable functionalities. The possibilities offered by systems in which continuous molecular layers are interfaced with inorganic 2D materials to form hybrid organic/inorganic van der Waals heterostructures are emphasized. Similar to their inorganic counterpart, the hybrid structures have been exploited to put forward novel device architectures, such as antiambipolar transistors and barristors. Moreover, specific molecular groups can be employed to modify intrinsic properties and confer new capabilities to 2D materials. In particular, it is highlighted how molecular self-assembly at the surface of 2D materials can be mastered to achieve precise control over position and density of (molecular) functional groups, paving the way for a new class of hybrid functional materials whose final properties can be selected by careful molecular design.Hybrid van der Waals heterostructures, in which 2D materials are combined with molecular layers, allow the creation of novel systems with unprecedented functions. The immense potentials of molecular approaches to change fundamental properties of 2D materials, create functional interfaces, and generate new device architectures, which thereby potentially open new technological avenues, are reviewed.
      PubDate: 2018-02-14T02:12:15.51209-05:0
      DOI: 10.1002/adma.201706103
       
  • A Sulfur–Limonene-Based Electrode for Lithium–Sulfur Batteries:
           High-Performance by Self-Protection
    • Authors: Feixiang Wu; Shuangqiang Chen, Vesna Srot, Yuanye Huang, Shyam Kanta Sinha, Peter A. Aken, Joachim Maier, Yan Yu
      Abstract: The lithium–sulfur battery is considered as one of the most promising energy storage systems and has received enormous attentions due to its high energy density and low cost. However, polysulfide dissolution and the resulting shuttle effects hinder its practical application unless very costly solutions are considered. Herein, a sulfur-rich polymer termed sulfur–limonene polysulfide is proposed as powerful electroactive material that uniquely combines decisive advantages and leads out of this dilemma. It is amenable to a large-scale synthesis by the abundant, inexpensive, and environmentally benign raw materials sulfur and limonene (from orange and lemon peels). Moreover, owing to self-protection and confinement of lithium sulfide and sulfur, detrimental dissolution and shuttle effects are successfully avoided. The sulfur–limonene-based electrodes (without elaborate synthesis or surface modification) exhibit excellent electrochemical performances characterized by high discharge capacities (≈1000 mA h g−1 at C/2) and remarkable cycle stability (average fading rate as low as 0.008% per cycle during 300 cycles).A sulfur–limonene-based cathode material is produced by large-scale synthesis using the abundant, inexpensive, and environmentally benign raw materials sulfur and limonene. Owing to self-protection and confinement of lithium sulfide and sulfur, detrimental dissolution and shuttle effects are successfully avoided. As a result, the sulfur–limonene-based electrodes exhibit excellent electrochemical performances and remarkable cycle stability.
      PubDate: 2018-02-14T02:06:08.672413-05:
      DOI: 10.1002/adma.201706643
       
  • Nanomaterials Safer-by-Design: An Environmental Safety Perspective
    • Authors: Sijie Lin; Tianyu Yu, Zhenyang Yu, Xialin Hu, Daqiang Yin
      Abstract: Designing safer nanomaterials and nanostructures has gained increasing attention in the field of nanoscience and technology in recent years. Based on the body of experimental evidence contributed by environmental health and safety studies, materials scientists now have a better grasp on the relationships between the nanomaterials' physicochemical characteristics and their hazard/safety profiles. Therefore, it is expected that an integration of design synthesis and safety assessment will foster nanomaterials safer-by-design by considering both applications and implications. From the environmental safety perspective, the most recent advances that demonstrate effective nanomaterials safer-by-design are highlighted.Recent progress in safer-by-design nanomaterials is examined. Through careful dissection, various “safer-by-design” strategies that have been successfully implemented to make safer metal oxide, carbon-based, silica, and rare earth oxide nanomaterials are highlighted. The gap between nanomaterial research and safety-assessment communities is also presented and an outlook for future research directions provided.
      PubDate: 2018-02-13T03:05:42.975926-05:
      DOI: 10.1002/adma.201705691
       
  • Biomedical Applications of Recombinant Silk-Based Materials
    • Authors: Tamara Bernadette Aigner; Elise DeSimone, Thomas Scheibel
      Abstract: Silk is mostly known as a luxurious textile, which originates from silkworms first cultivated in China. A deeper look into the variety of silk reveals that it can be used for much more, in nature and by humanity. For medical purposes, natural silks were recognized early as a potential biomaterial for surgical threads or wound dressings; however, as biomedical engineering advances, the demand for high-performance, naturally derived biomaterials becomes more pressing and stringent. A common problem of natural materials is their large batch-to-batch variation, the quantity available, their potentially high immunogenicity, and their fast biodegradation. Some of these common problems also apply to silk; therefore, recombinant approaches for producing silk proteins have been developed. There are several research groups which study and utilize various recombinantly produced silk proteins, and many of these have also investigated their products for biomedical applications. This review gives a critical overview over of the results for applications of recombinant silk proteins in biomedical engineering.Recombinant silk proteins are an interesting class of biopolymers that are well-suited for biomedical applications. In this review, studies on the use of recombinant silk proteins are summarized, and important conclusions are given. The review also highlights the best features of recombinant silk proteins as a biomaterial, and exciting future directions.
      PubDate: 2018-02-13T02:13:46.293761-05:
      DOI: 10.1002/adma.201704636
       
  • Transient SHG Imaging on Ultrafast Carrier Dynamics of MoS2 Nanosheets
    • Authors: Houk Jang; Krishna P. Dhakal, Kyung-Il Joo, Won Seok Yun, Sachin M. Shinde, Xiang Chen, Soon Moon Jeong, Suk Woo Lee, Zonghoon Lee, JaeDong Lee, Jong-Hyun Ahn, Hyunmin Kim
      Abstract: Understanding the collaborative behaviors of the excitons and phonons that result from light–matter interactions is important for interpreting and optimizing the underlying fundamental physics at work in devices made from atomically thin materials. In this study, the generation of exciton-coupled phonon vibration from molybdenum disulfide (MoS2) nanosheets in a pre-excitonic resonance condition is reported. A strong rise-to-decay profile for the transient second-harmonic generation (TSHG) of the probe pulse is achieved by applying substantial (20%) beam polarization normal to the nanosheet plane, and tuning the wavelength of the pump beam to the absorption of the A-exciton. The time-dependent TSHG signals clearly exhibit acoustic phonon generation at vibration modes below 10 cm−1 (close to the Γ point) after the photoinduced energy is transferred from exciton to phonon in a nonradiative fashion. Interestingly, by observing the TSHG signal oscillation period from MoS2 samples of varying thicknesses, the speed of the supersonic waves generated in the out-of-plane direction (Mach 8.6) is generated. Additionally, TSHG microscopy reveals critical information about the phase and amplitude of the acoustic phonons from different edge chiralities (armchair and zigzag) of the MoS2 monolayers. This suggests that the technique could be used more broadly to study ultrafast physics and chemistry in low-dimensional materials and their hybrids with ultrahigh fidelity.Imaging transient second-harmonic generation (TSHG) enables spatially resolved analysis of exciton-coupled phonon-vibration from atomically layered MoS2. The TSHG microscopy reveals critical information about frequency, phase, and amplitude of acoustic phonons in a monolayer and multilayer MoS2 sample simultaneously, thus uncovering the speed of sounds generated in the materials and chiral-dependent acoustic phonon vibrations.
      PubDate: 2018-02-13T02:12:14.904687-05:
      DOI: 10.1002/adma.201705190
       
  • Tunable Tribotronic Dual-Gate Logic Devices Based on 2D MoS2 and
           Black Phosphorus
    • Authors: Guoyun Gao; Bensong Wan, Xingqiang Liu, Qijun Sun, Xiaonian Yang, Longfei Wang, Caofeng Pan, Zhong Lin Wang
      Abstract: With the Moore's law hitting the bottleneck of scaling-down in size (below 10 nm), personalized and multifunctional electronics with an integration of 2D materials and self-powering technology emerge as a new direction of scientific research. Here, a tunable tribotronic dual-gate logic device based on a MoS2 field-effect transistor (FET), a black phosphorus FET and a sliding mode triboelectric nanogenerator (TENG) is reported. The triboelectric potential produced from the TENG can efficiently drive the transistors and logic devices without applying gate voltages. High performance tribotronic transistors are achieved with on/off ratio exceeding 106 and cutoff current below 1 pA μm–1. Tunable electrical behaviors of the logic device are also realized, including tunable gains (improved to ≈13.8) and power consumptions (≈1 nW). This work offers an active, low-power-consuming, and universal approach to modulate semiconductor devices and logic circuits based on 2D materials with TENG, which can be used in microelectromechanical systems, human–machine interfacing, data processing and transmission.A tunable tribotronic dual-gate logic device based on a MoS2 field-effect transistor, black phosphorus transistors, and a sliding mode triboelectric nanogenerator (TENG) is reported. Triboelectric potential produced from the TENG can efficiently drive the transistors and inverters without applying gate voltages. Tunable electrical behaviors of the inverters are also realized, including tunable gains and power consumptions.
      PubDate: 2018-02-13T02:11:18.428151-05:
      DOI: 10.1002/adma.201705088
       
  • A Magnetofluorescent Carbon Dot Assembly as an Acidic H2O2-Driven
           Oxygenerator to Regulate Tumor Hypoxia for Simultaneous Bimodal Imaging
           and Enhanced Photodynamic Therapy
    • Authors: Qingyan Jia; Jiechao Ge, Weimin Liu, Xiuli Zheng, Shiqing Chen, Yongmei Wen, Hongyan Zhang, Pengfei Wang
      Abstract: Recent studies indicate that carbon dots (CDs) can efficiently generate singlet oxygen (1O2) for photodynamic therapy (PDT) of cancer. However, the hypoxic tumor microenvironment and rapid consumption of oxygen in the PDT process will severely limit therapeutic effects of CDs due to the oxygen-dependent PDT. Thus, it is becoming particularly important to develop a novel CD as an in situ tumor oxygenerator for overcoming hypoxia and substantially enhancing the PDT efficacy. Herein, for the first time, magnetofluorescent Mn-CDs are successfully prepared using manganese(II) phthalocyanine as a precursor. After cooperative self-assembly with DSPE-PEG, the obtained Mn-CD assembly can be applied as a smart contrast agent for both near-infrared fluorescence (FL) (maximum peak at 745 nm) and T1-weighted magnetic resonance (MR) (relaxivity value of 6.97 mM−1 s−1) imaging. More interestingly, the Mn-CD assembly can not only effectively produce 1O2 (quantum yield of 0.40) but also highly catalyze H2O2 to generate oxygen. These collective properties of the Mn-CD assembly enable it to be utilized as an acidic H2O2-driven oxygenerator to increase the oxygen concentration in hypoxic solid tumors for simultaneous bimodal FL/MR imaging and enhanced PDT. This work explores a new biomedical use of CDs and provides a versatile carbon nanomaterial candidate for multifunctional nanotheranostic applications.A magnetofluorescent Mn-CD assembly is designed and prepared as an acidic H2O2-driven oxygenerator to regulate the hypoxic tumor microenvironment for simultaneous bimodal fluorescence/T1-weighted magnetic resonance imaging and enhanced photodynamic therapy of solid tumors. This work demonstrates a new biomedical use of CDs and provides a versatile carbon nanomaterial candidate for multifunctional nanotheranostic applications.
      PubDate: 2018-02-13T02:08:24.22868-05:0
      DOI: 10.1002/adma.201706090
       
  • Breaking the Current-Retention Dilemma in Cation-Based Resistive Switching
           Devices Utilizing Graphene with Controlled Defects
    • Authors: Xiaolong Zhao; Jun Ma, Xiangheng Xiao, Qi Liu, Lin Shao, Di Chen, Sen Liu, Jiebin Niu, Xumeng Zhang, Yan Wang, Rongrong Cao, Wei Wang, Zengfeng Di, Hangbing Lv, Shibing Long, Ming Liu
      Abstract: Cation-based resistive switching (RS) devices, dominated by conductive filaments (CF) formation/dissolution, are widely considered for the ultrahigh density nonvolatile memory application. However, the current-retention dilemma that the CF stability deteriorates greatly with decreasing compliance current makes it hard to decrease operating current for memory application and increase driving current for selector application. By centralizing/decentralizing the CF distribution, this current-retention dilemma of cation-based RS devices is broken for the first time. Utilizing the graphene impermeability, the cation injecting path to the RS layer can be well modulated by structure-defective graphene, leading to control of the CF quantity and size. By graphene defect engineering, a low operating current (≈1 µA) memory and a high driving current (≈1 mA) selector are successfully realized in the same material system. Based on systematically materials analysis, the diameter of CF, modulated by graphene defect size, is the major factor for CF stability. Breakthrough in addressing the current-retention dilemma will instruct the future implementation of high-density 3D integration of RS memory immune to crosstalk issues.Cation-based resistive switching (RS) devices are widely considered for memory and selector application in the one-selector-one-resistor (1S1R) scheme for the next-generation nonvolatile memory application. Here, centralizing/decentralizing the conductive filament distribution is proposed to break the current-retention dilemma of cation-based RS device by modulating the filament stability. Ultimately, this method helps to realize low-current memory and high On-state current selector for 1S1R array application.
      PubDate: 2018-02-13T02:06:39.901282-05:
      DOI: 10.1002/adma.201705193
       
  • In Situ Grown Epitaxial Heterojunction Exhibits High-Performance
           Electrocatalytic Water Splitting
    • Authors: Changrong Zhu; An-Liang Wang, Wen Xiao, Dongliang Chao, Xiao Zhang, Nguyen Huy Tiep, Shi Chen, Jiani Kang, Xin Wang, Jun Ding, John Wang, Hua Zhang, Hong Jin Fan
      Abstract: Electrocatalytic performance can be enhanced by engineering a purposely designed nanoheterojunction and fine-tuning the interface electronic structure. Herein a new approach of developing atomic epitaxial in-growth in Co-Ni3N nanowires array is devised, where a nanoconfinement effect is reinforced at the interface. The Co-Ni3N heterostructure array is formed by thermal annealing NiCo2O4 precursor nanowires under an optimized condition, during which the nanowire morphology is retained. The epitaxial in-growth structure of Co-Ni3N at nanometer scale facilitates the electron transfer between the two different domains at the epitaxial interface, leading to a significant enhancement in catalytic activities for both hydrogen and oxygen evolution reactions (10 and 16 times higher in the respective turn-over frequency compared to Ni3N-alone nanorods). The interface transfer effect is verified by electronic binding energy shift and density functional theory (DFT) calculations. This nanoconfinement effect occurring during in situ atomic epitaxial in-growth of the two compatible materials shows an effective pathway toward high-performance electrocatalysis and energy storages.Epitaxial interface boosts performance Co-Ni3N nanorod arrays with an atomic epitaxial interface are synthesized which exhibit significant enhancement in catalytic activities for both hydrogen and oxygen evolution reactions. A nanoconfinement effect is proposed to facilitate the interface charge transfer.
      PubDate: 2018-02-13T02:05:53.333882-05:
      DOI: 10.1002/adma.201705516
       
  • Graphene–Graphene Interactions: Friction, Superlubricity, and
           Exfoliation
    • Authors: Robert C. Sinclair; James L. Suter, Peter V. Coveney
      Abstract: Graphite's lubricating properties due to the “weak” interactions between individual layers have long been known. However, these interactions are not weak enough to allow graphite to readily exfoliate into graphene on a large scale. Separating graphite layers down to a single sheet is an intense area of research as scientists attempt to utilize graphene's superlative properties. The exfoliation and processing of layered materials is governed by the friction between layers. Friction on the macroscale can be intuitively understood, but there is little understanding of the mechanisms involved in nanolayered materials. Using molecular dynamics and a new forcefield, graphene's unusual behavior in a superlubric state is examined, and the energy dissipated between two such surfaces sliding past each other is shown. The dependence of friction on temperature and surface roughness is described, and agreement with experiment is reported. The accuracy of the simulated behavior enables the processes that drive exfoliation of graphite into individual graphene sheets to be described. Taking into account the friction between layers, a peeling mechanism of exfoliation is predicted to be of lower energy cost than shearing.Graphite's lubricating properties due to the “weak” interactions between individual layers, have long been known. However, graphene still cannot be exfoliated on a large scale. A new classical molecular dynamics forcefield is applied to unravel the remarkable interactions between graphene sheets. It is found that peeling graphene sheets apart, rather than shearing, is an easier route to exfoliation.
      PubDate: 2018-02-13T02:00:01.016973-05:
      DOI: 10.1002/adma.201705791
       
  • Inherently Eu2+/Eu3+ Codoped Sc2O3 Nanoparticles as High-Performance
           Nanothermometers
    • Authors: Yue Pan; Xiaoji Xie, Qianwen Huang, Chao Gao, Yangbo Wang, Lingxiao Wang, Bingxiao Yang, Haiquan Su, Ling Huang, Wei Huang
      Abstract: Luminescent nanothermometers have shown competitive superiority for contactless and noninvasive temperature probing especially at the nanoscale. Herein, we report the inherently Eu2+/Eu3+ codoped Sc2O3 nanoparticles synthesized via a one-step and controllable thermolysis reaction where Eu3+ is in-situ reduced to Eu2+ by oleylamine. The stable luminescence emission of Eu3+ as internal standard and the sensitive response of Eu2+ emission to temperature as probe comprise a perfect ratiometric nanothermometer with wide-range temperature probing (77–267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K–1 at 267 K). The in situ reduction of Eu3+ to Eu2+ ensures both uniform distribution in the crystal lattice and simultaneous response upon light excitation of Eu2+/Eu3+. To widen this concept, Tb3+ is codoped as additional internal reference for tunable temperature probing range.Inherently Eu2+/Eu3+ codoped Sc2O3 nanoparticles are synthesized via a one-step and controllable thermolysis reaction where Eu3+ is in-situ reduced to Eu2+ by oleylamine. The emission of Eu2+ as internal standard and Eu3+ emission as probe comprise a perfect ratiometric nanothermometer with wide temperature probing range (77–267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K−1 at 267 K).
      PubDate: 2018-02-12T03:06:02.980555-05:
      DOI: 10.1002/adma.201705256
       
  • Stable Metal–Organic Frameworks: Design, Synthesis, and Applications
    • Authors: Shuai Yuan; Liang Feng, Kecheng Wang, Jiandong Pang, Matheiu Bosch, Christina Lollar, Yujia Sun, Junsheng Qin, Xinyu Yang, Peng Zhang, Qi Wang, Lanfang Zou, Yingmu Zhang, Liangliang Zhang, Yu Fang, Jialuo Li, Hong-Cai Zhou
      Abstract: Metal–organic frameworks (MOFs) are an emerging class of porous materials with potential applications in gas storage, separations, catalysis, and chemical sensing. Despite numerous advantages, applications of many MOFs are ultimately limited by their stability under harsh conditions. Herein, the recent advances in the field of stable MOFs, covering the fundamental mechanisms of MOF stability, design, and synthesis of stable MOF architectures, and their latest applications are reviewed. First, key factors that affect MOF stability under certain chemical environments are introduced to guide the design of robust structures. This is followed by a short review of synthetic strategies of stable MOFs including modulated synthesis and postsynthetic modifications. Based on the fundamentals of MOF stability, stable MOFs are classified into two categories: high-valency metal–carboxylate frameworks and low-valency metal–azolate frameworks. Along this line, some representative stable MOFs are introduced, their structures are described, and their properties are briefly discussed. The expanded applications of stable MOFs in Lewis/Brønsted acid catalysis, redox catalysis, photocatalysis, electrocatalysis, gas storage, and sensing are highlighted. Overall, this review is expected to guide the design of stable MOFs by providing insights into existing structures, which could lead to the discovery and development of more advanced functional materials.Stable metal–organic frameworks (MOFs) with high resistance to harsh chemical environments are reviewed with regard to recent progress in their research and development. Fundamental mechanisms of MOF stability, design and synthesis of stable MOF architectures, and their latest applications are summarized, providing a fundamental outline for the discovery of new stable MOFs.
      PubDate: 2018-02-12T02:30:16.906773-05:
      DOI: 10.1002/adma.201704303
       
  • Uncovering the Circular Polarization Potential of Chiral Photonic
           Cellulose Films for Photonic Applications
    • Authors: Hongzhi Zheng; Wanru Li, Wen Li, Xiaojun Wang, Zhiyong Tang, Sean Xiao-An Zhang, Yan Xu
      Abstract: Circularly polarized light (CPL) is central to photonic technologies. A key challenge lies in developing a general route for generation of CPL with tailored chiroptical activity using low-cost raw materials suitable for scale-up. This study presents that cellulose films with photonic bandgaps (PBG) and left-handed helical sense have an intrinsic ability for circular polarization leading to PBG-based CPL with extraordinary g  values, well-defiend handedness, and tailorable wavelength by the PBG change. Using such cellulose films, incident light ranging from near-UV to near-IR can be transformed to passive L-CPL and R-CPL with viewing-side-dependent handedness and g  values up to 0.87, and spontaneous emission transformed to R-CPL emission with g  values up to 0.68. Unprecedented evidence is presented with theoretical underpinning that the PBG effect can stimulate the R-CPL emission. The potential of cellulose-based CPL films for polarization-based encryption is illustrated. The evaporation-induced self-assembly coupled with nanoscale mesogens of cellulose nanocrystals opens new venues for technological advances and enables a versatile strategy for rational design and scalable manufacturing of organic and inorganic CPL films for photonic applications.Chiral photonic cellulose films have intrinsic ability to generate and manipulate circularly polarized light (CPL) with extraordinary g  values in a broad spectral regime. The CPL handedness is well defined, and the wavelength control is simple to realize. Photonic bandgap effects cause stimulated CPL. It presents a versatile and scalable strategy for customized CPL materials using renewable cellulose for photonic applications.
      PubDate: 2018-02-12T02:28:57.367812-05:
      DOI: 10.1002/adma.201705948
       
  • Structural Engineering of 2D Nanomaterials for Energy Storage and
           Catalysis
    • Authors: Yue Zhu; Lele Peng, Zhiwei Fang, Chunshuang Yan, Xiao Zhang, Guihua Yu
      Abstract: Research on 2D nanomaterials is rising to an unprecedented height and will continue to remain a very important topic in materials science. In parallel with the discovery of new candidate materials and exploration of their unique characteristics, there are intensive interests to rationally control and tune the properties of 2D nanomaterials in a predictable manner. Considerable attention is focused on modifying these materials structurally or engineering them into designed architectures to meet requirements for specific applications. Recent advances in such structural engineering strategies have demonstrated their ability to overcome current material limitations, showing great promise for promoting device performance to a new level in many energy-related applications. Existing in many forms, these strategies can be categorized based on how they intrinsically or extrinsically alter the pristine structure. Achieved through various synthetic routes and practiced in a range of different material systems, they usually share common descriptors that predestine them to be effective in certain circumstances. Therefore, understanding the underlying mechanism of these strategies to provide fundamental insights into structural design and property tailoring is of critical importance. Here, the most recent development of structural engineering of 2D nanomaterials and their significant effects in energy storage and catalysis technologies are addressed.Structural engineering serves as an important material design concept and offers new inroads into the field of 2D nanomaterials, including both conventional material engineering methods and novel nanotechnology approaches. Recent progress of structural engineering strategies for 2D nanomaterials and their implications for advanced energy storage and catalysis technologies have been presented in this progress report.
      PubDate: 2018-02-12T02:27:04.011506-05:
      DOI: 10.1002/adma.201706347
       
  • Engineered Living Materials: Prospects and Challenges for Using Biological
           Systems to Direct the Assembly of Smart Materials
    • Authors: Peter Q. Nguyen; Noémie-Manuelle Dorval Courchesne, Anna Duraj-Thatte, Pichet Praveschotinunt, Neel S. Joshi
      Abstract: Vast potential exists for the development of novel, engineered platforms that manipulate biology for the production of programmed advanced materials. Such systems would possess the autonomous, adaptive, and self-healing characteristics of living organisms, but would be engineered with the goal of assembling bulk materials with designer physicochemical or mechanical properties, across multiple length scales. Early efforts toward such engineered living materials (ELMs) are reviewed here, with an emphasis on engineered bacterial systems, living composite materials which integrate inorganic components, successful examples of large-scale implementation, and production methods. In addition, a conceptual exploration of the fundamental criteria of ELM technology and its future challenges is presented. Cradled within the rich intersection of synthetic biology and self-assembling materials, the development of ELM technologies allows the power of biology to be leveraged to grow complex structures and objects using a palette of bio-nanomaterials.Engineered living materials (ELMs) harness cellular processes to assimilate energy, carbon, and other nutrients from their environment into the molecular building blocks of materials and assemble those building blocks into multiscale biomaterials. Relevant fundamental advances in genetic engineering, biosensing, and biomanufacturing are reviewed, in addition to examples of ELMs with autonomous, adaptive, and self-renewing characteristics.
      PubDate: 2018-02-12T02:25:56.242036-05:
      DOI: 10.1002/adma.201704847
       
  • Structuring of Hydrogels across Multiple Length Scales for Biomedical
           Applications
    • Authors: Megan E. Cooke; Simon W. Jones, Britt ter Horst, Naiem Moiemen, Martyn Snow, Gurpreet Chouhan, Lisa J. Hill, Maryam Esmaeli, Richard J. A. Moakes, James Holton, Rajpal Nandra, Richard L. Williams, Alan M. Smith, Liam M. Grover
      Abstract: The development of new materials for clinical use is limited by an onerous regulatory framework, which means that taking a completely new material into the clinic can make translation economically unfeasible. One way to get around this issue is to structure materials that are already approved by the regulator, such that they exhibit very distinct physical properties and can be used in a broader range of clinical applications. Here, the focus is on the structuring of soft materials at multiple length scales by modifying processing conditions. By applying shear to newly forming materials, it is possible to trigger molecular reorganization of polymer chains, such that they aggregate to form particles and ribbon-like structures. These structures then weakly interact at zero shear forming a solid-like material. The resulting self-healing network is of particular use for a range of different biomedical applications. How these materials are used to allow the delivery of therapeutic entities (cells and proteins) and as a support for additive layer manufacturing of larger-scale tissue constructs is discussed. This technology enables the development of a range of novel materials and structures for tissue augmentation and regeneration.Structured soft materials have the potential to revolutionize regenerative medicine. By imparting shear during processing, it is possible to take the small number of materials approved by medical regulators and create self-healing polymeric structures. How so-called fluid gels can facilitate the delivery of cells and proteins and enable additive layer manufacturing of complex biological structures is discussed.
      PubDate: 2018-02-12T02:23:59.359074-05:
      DOI: 10.1002/adma.201705013
       
  • Reassembly of 89Zr-Labeled Cancer Cell Membranes into Multicompartment
           Membrane-Derived Liposomes for PET-Trackable Tumor-Targeted Theranostics
    • Authors: Bo Yu; Shreya Goel, Dalong Ni, Paul A. Ellison, Cerise M. Siamof, Dawei Jiang, Liang Cheng, Lei Kang, Faquan Yu, Zhuang Liu, Todd E. Barnhart, Qianjun He, Han Zhang, Weibo Cai
      Abstract: Nanoengineering of cell membranes holds great potential to revolutionize tumor-targeted theranostics, owing to their innate biocompatibility and ability to escape from the immune and reticuloendothelial systems. However, tailoring and integrating cell membranes with drug and imaging agents into one versatile nanoparticle are still challenging. Here, multicompartment membrane-derived liposomes (MCLs) are developed by reassembling cancer cell membranes with Tween-80, and are used to conjugate 89Zr via deferoxamine chelator and load tetrakis(4-carboxyphenyl) porphyrin for in vivo noninvasive quantitative tracing by positron emission tomography imaging and photodynamic therapy (PDT), respectively. Radiolabeled constructs, 89Zr-Df-MCLs, demonstrate excellent radiochemical stability in vivo, target 4T1 tumors by the enhanced permeability and retention effect, and are retained long-term for efficient and effective PDT while clearing gradually from the reticuloendothelial system via hepatobiliary excretion. Toxicity evaluation confirms that the MCLs do not impose acute or chronic toxicity in intravenously injected mice. Additionally, 89Zr-labeled MCLs can execute rapid and highly sensitive lymph node mapping, even for deep-seated sentinel lymph nodes. The as-developed cell membrane reassembling route to MCLs could be extended to other cell types, providing a versatile platform for disease theranostics by facilely and efficiently integrating various multifunctional agents.Systematic noninvasive tracking and quantitative investigation of 89Zr-labeled multicompartment membrane-derived liposomes (89Zr-Df-MCLs) is performed to demonstrate rapid clearance of 89Zr-Df-MCLs, which is estimated to be over 63% injected dose (ID) at 72 h post-injection through the hepatobiliary route. 89Zr-Df-MCLs are developed as contrast agents for positron emission tomography for in vivo imaging of tumors and mapping of lymph nodes, as well as for fluorescence imaging and photodynamic therapy after loading with a porphyrin cargo.
      PubDate: 2018-02-12T02:23:09.243917-05:
      DOI: 10.1002/adma.201704934
       
  • Liquid-Crystalline Dynamic Networks Doped with Gold Nanorods Showing
           Enhanced Photocontrol of Actuation
    • Authors: Xili Lu; Hu Zhang, Guoxia Fei, Bing Yu, Xia Tong, Hesheng Xia, Yue Zhao
      Abstract: A near-infrared-light (NIR)- and UV-light-responsive polymer nanocomposite is synthesized by doping polymer-grafted gold nanorods into azobenzene liquid-crystalline dynamic networks (AuNR-ALCNs). The effects of the two different photoresponsive mechanisms, i.e., the photochemical reaction of azobenzene and the photothermal effect from the surface plasmon resonance of the AuNRs, are investigated by monitoring both the NIR- and UV-light-induced contraction forces of the oriented AuNR-ALCNs. By taking advantage of the material's easy processability, bilayer-structured actuators can be fabricated to display photocontrollable bending/unbending directions, as well as localized actuations through programmed alignment of azobenzene mesogens in selected regions. Versatile and complex motions enabled by the enhanced photocontrol of actuation are demonstrated, including plastic “athletes” that can execute light-controlled push-ups or sit-ups, and a light-driven caterpillar-inspired walker that can crawl forward on a ratcheted substrate at a speed of about 13 mm min-1. Moreover, the photomechanical effects arising from the two types of light-triggered molecular motion, i.e., the trans–cis photoisomerization and a liquid-crystalline–isotropic phase transition of the azobenzene mesogens, are added up to design a polymer “crane” that is capable of performing light-controlled, robot-like, concerted macroscopic motions including grasping, lifting up, lowering down, and releasing an object.The photomechanical effects of two types of light-triggered molecular motions in a liquid-crystalline (LC) dynamic network, i.e., the LC–isotropic phase transition and the trans–cis photoisomerization of azobenzene mesogens, are added up to make a polymer “crane” that is capable of performing light-controlled, robot-like motions to produce physical work.
      PubDate: 2018-02-12T02:14:09.830589-05:
      DOI: 10.1002/adma.201706597
       
  • Reversible and Precisely Controllable p/n-Type Doping of MoTe2 Transistors
           through Electrothermal Doping
    • Authors: Yuan-Ming Chang; Shih-Hsien Yang, Che-Yi Lin, Chang-Hung Chen, Chen-Hsin Lien, Wen-Bin Jian, Keiji Ueno, Yuen-Wuu Suen, Kazuhito Tsukagoshi, Yen-Fu Lin
      Abstract: Precisely controllable and reversible p/n-type electronic doping of molybdenum ditelluride (MoTe2) transistors is achieved by electrothermal doping (E-doping) processes. E-doping includes electrothermal annealing induced by an electric field in a vacuum chamber, which results in electron (n-type) doping and exposure to air, which induces hole (p-type) doping. The doping arises from the interaction between oxygen molecules or water vapor and defects of tellurium at the MoTe2 surface, and allows the accurate manipulation of p/n-type electrical doping of MoTe2 transistors. Because no dopant or special gas is used in the E-doping processes of MoTe2, E-doping is a simple and efficient method. Moreover, through exact manipulation of p/n-type doping of MoTe2 transistors, quasi-complementary metal oxide semiconductor adaptive logic circuits, such as an inverter, not or gate, and not and gate, are successfully fabricated. The simple method, E-doping, adopted in obtaining p/n-type doping of MoTe2 transistors undoubtedly has provided an approach to create the electronic devices with desired performance.Precisely controllable and reversible doping of molybdenum ditelluride (MoTe2) transistors is achieved by electrothermal doping (E-doping) processes. E-doping includes electrothermal annealing induced by an electric field in vacuum, which results in electron (n-type) doping, and exposure to air, which induces hole (p-type) doping. No dopant or gas is used in the E-doping processes, E-doping is a simple and efficient method.
      PubDate: 2018-02-12T02:01:14.119732-05:
      DOI: 10.1002/adma.201706995
       
  • High-Performance Organic Bulk-Heterojunction Solar Cells Based on
           Multiple-Donor or Multiple-Acceptor Components
    • Authors: Wenchao Huang; Pei Cheng, Yang (Michael) Yang, Gang Li, Yang Yang
      Abstract: Organic solar cells (OSCs) based on bulk heterojunction structures are promising candidates for next-generation solar cells. However, the narrow absorption bandwidth of organic semiconductors is a critical issue resulting in insufficient usage of the energy from the solar spectrum, and as a result, it hinders performance. Devices based on multiple-donor or multiple-acceptor components with complementary absorption spectra provide a solution to address this issue. OSCs based on multiple-donor or multiple-acceptor systems have achieved power conversion efficiencies over 12%. Moreover, the introduction of an additional component can further facilitate charge transfer and reduce charge recombination through cascade energy structure and optimized morphology. This progress report provides an overview of the recent progress in OSCs based on multiple-donor (polymer/polymer, polymer/dye, and polymer/small molecule) or multiple-acceptor (fullerene/fullerene, fullerene/nonfullerene, and nonfullerene/nonfullerene) components.This progress report provides an overview of the most impactful recent progress in high-performance organic solar cells based on multiple-donor (polymer/polymer, polymer/dye, and polymer/small molecule) or multiple-acceptor (fullerene/fullerene, fullerene/nonfullerene, and nonfullerene/nonfullerene) components, focusing particularly on the interactions between different components from the perspective of morphology and photophysics.
      PubDate: 2018-01-15T04:39:36.72468-05:0
      DOI: 10.1002/adma.201705706
       
  • Photothermal-Responsive Conjugated Polymer Nanoparticles for Remote
           Control of Gene Expression in Living Cells
    • Authors: Yunxia Wang; Shengliang Li, Pengbo Zhang, Haotian Bai, Liheng Feng, Fengting Lv, Libing Liu, Shu Wang
      Abstract: Remote control and noninvasive manipulation of cellular bioprocess has received intensive attention as a powerful technology to control cell functions. Here, a strategy is developed to remotely control intracellular gene expression with high spatial and temporal resolutions by using photothermal-responsive conjugated polymer nanoparticles (CPNs) as the transducer under near-infrared light irradiation. After being modified with positive charged peptide, the CPNs with superior photothermal conversion capacity could effectively coat on the surface of living cells and generate localized heat to trigger target gene expression. The heat-inducible heat shock protein-70 promoter starts transcription of downstream EGFP gene in response to heat shock, thus producing green fluorescent protein in the living cells. The combination of heat-inducible gene promoter and photothermal-responsive CPNs provides a method for the development of thermogenetics.A strategy is developed to remotely control intracellular gene expression with high spatial and temporal resolution by using photothermal-responsive conjugated polymer nanoparticles (CPNs) as the transducer under near-infrared light irradiation. The heat-inducible heat shock protein-70 promoter starts transcription of downstream EGFP gene in response to heat shock, thus producing green fluorescent protein protein in the living cells. The combination of the heat-inducible gene promoter and CPNs with good photothermal conversion capacity provides a method for the development of thermogenetics.
      PubDate: 2018-01-12T03:37:41.11002-05:0
      DOI: 10.1002/adma.201705418
       
  • A Self-Powered and Flexible Organometallic Halide Perovskite Photodetector
           with Very High Detectivity
    • Authors: Siu-Fung Leung; Kang-Ting Ho, Po-Kai Kung, Vincent K. S. Hsiao, Husam N. Alshareef, Zhong Lin Wang, Jr-Hau He
      Abstract: Flexible and self-powered photodetectors (PDs) are highly desirable for applications in image sensing, smart building, and optical communications. In this paper, a self-powered and flexible PD based on the methylammonium lead iodide (CH3NH3PBI3) perovskite is demonstrated. Such a self-powered PD can operate even with irregular motion such as human finger tapping, which enables it to work without a bulky external power source. In addition, with high-quality CH3NH3PBI3 perovskite thin film fabricated with solvent engineering, the PD exhibits an impressive detectivity of 1.22 × 1013 Jones. In the self-powered voltage detection mode, it achieves a large responsivity of up to 79.4 V mW−1 cm−2 and a voltage response of up to ≈90%. Moreover, as the PD is made of flexible and transparent polymer films, it can operate under bending and functions at 360 ° of illumination. As a result, the self-powered, flexible, 360 ° omnidirectional perovskite PD, featuring high detectivity and responsivity along with real-world sensing capability, suggests a new direction for next-generation optical communications, sensing, and imaging applications.A flexible and self-powered organometallic halide perovskite photodetector is demonstrated that features an impressive detectivity of 1.22 × 1013 Jones and a large responsivity of up to 79.4 V mW−1 cm2. These results demonstrate a promising approach for developing a flexible and self-powered photodetector featuring high detectivity, responsivity, and excellent compatibility in various situations, particularly for outdoor applications.
      PubDate: 2018-01-10T03:52:42.770964-05:
      DOI: 10.1002/adma.201704611
       
  • Large-Area Atomic Layers of the Charge-Density-Wave Conductor TiSe2
    • Authors: Hong Wang; Yu Chen, Martial Duchamp, Qingsheng Zeng, Xuewen Wang, Siu Hon Tsang, Hongling Li, Lin Jing, Ting Yu, Edwin Hang Tong Teo, Zheng Liu
      Abstract: Layered transition metal (Ti, Ta, Nb, etc.) dichalcogenides are important prototypes for the study of the collective charge density wave (CDW). Reducing the system dimensionality is expected to lead to novel properties, as exemplified by the discovery of enhanced CDW order in ultrathin TiSe2. However, the syntheses of monolayer and large-area 2D CDW conductors can currently only be achieved by molecular beam epitaxy under ultrahigh vacuum. This study reports the growth of monolayer crystals and up to 5 × 105 µm2 large films of the typical 2D CDW conductor—TiSe2—by ambient-pressure chemical vapor deposition. Atomic resolution scanning transmission electron microscopy indicates the as-grown samples are highly crystalline 1T-phase TiSe2. Variable-temperature Raman spectroscopy shows a CDW phase transition temperature of 212.5 K in few layer TiSe2, indicative of high crystal quality. This work not only allows the exploration of many-body state of TiSe2 in 2D limit but also offers the possibility of utilizing large-area TiSe2 in ultrathin electronic devices.Large-area 2D charge-density-wave (CDW) conductor TiSe2 films are synthesized under ambient pressure by chemical vapor deposition. Low-temperature Raman measurement provides spectroscopic evidence that CDW order still emerges in monolayer TiSe2 and survives to a higher temperature than thick samples. This work offers the possibility of utilizing large-area TiSe2 in ultrathin electronic devices.
      PubDate: 2018-01-10T03:52:24.162428-05:
      DOI: 10.1002/adma.201704382
       
  • Magnetic-Induced-Piezopotential Gated MoS2 Field-Effect Transistor at Room
           Temperature
    • Authors: Yudong Liu; Junmeng Guo, Aifang Yu, Yang Zhang, Jinzong Kou, Ke Zhang, Rongmei Wen, Yan Zhang, Junyi Zhai, Zhong Lin Wang
      Abstract: Utilizing magnetic field directly modulating/turning the charge carrier transport behavior of field-effect transistor (FET) at ambient conditions is an enormous challenge in the field of micro–nanoelectronics. Here, a new type of magnetic-induced-piezopotential gated field-effect-transistor (MIPG-FET) base on laminate composites is proposed, which consists of Terfenol-D, a ferroelectric single crystal (PMNPT), and MoS2 flake. When applying an external magnetic field to the MIPG-FET, the piezopotential of PMNPT triggered by magnetostriction of the Terfenol-D can serve as the gate voltage to effectively modulate/control the carrier transport process and the corresponding drain current at room temperature. Considering the two polarization states of PMNPT, the drain current is diminished from 9.56 to 2.9 µA in the Pup state under a magnetic field of 33 mT, and increases from 1.41 to 4.93 µA in the Pdown state under a magnetic field of 42 mT and at a drain voltage of 3 V. The current on/off ratios in these states are 330% and 432%, respectively. This work provides a novel noncontact coupling method among magnetism, piezoelectricity, and semiconductor properties, which may have extremely important applications in magnetic sensors, memory and logic devices, micro-electromechanical systems, and human–machine interfacing.A magnetic-induced-piezopotential gated field-effect transistor consists of rare-earth Terfenol-D (TbxDy(1−x)Fe alloys), ferroelectric single crystal [Pb(Mn1/3Nb2/3)O3](1−x)-[PbTiO3]x, and 2D MoS2 flake, and realizes the magnetic field modulating carrier transport of the MoS2 flake instead of the gate voltage. This laminate composite device provides a new method for magnetic field tuning semiconductor properties besides spintronics.
      PubDate: 2018-01-10T03:51:44.427741-05:
      DOI: 10.1002/adma.201704524
       
  • Antigen-Directed Fabrication of a Multifunctional Nanovaccine with
           
    • Authors: Jinbin Pan; Yaqiong Wang, Cai Zhang, Xiaoyi Wang, Haoyu Wang, Jiaojiao Wang, Yizhong Yuan, Xu Wang, Xuejun Zhang, Chunshui Yu, Shao-Kai Sun, Xiu-Ping Yan
      Abstract: Current antigen-encapsulated multifunctional nanovaccines for oncotherapy suffer from limited antigen loading efficiency, low yield, tedious manufacture, and systemic toxicity. Here, an antigen-directed strategy for the fabrication of multifunctional nanovaccine with ultrahigh antigen loading efficiency in a facile way for tumor photothermal-immunotherapy is shown. As a proof of concept, a model antigen ovalbumin (OVA) is used as a natural carrier to load a representative theranostic agent indocyanine green (ICG). Mixing OVA and ICG in aqueous solution gives the simplest multifunctional nanovaccine so far. The nanovaccine owns antigen loading efficiency of 80.8%, high yield of>90%, intense near-infrared absorption and fluorescence, excellent reproducibility, good aqueous solubility and stability, and favorable biocompatibility. These merits not only guarantee sensitive labeling/tracking and efficient stimulation of dendritic cells, but also reliable imaging-guided photothermal-immunotherapy of tumors and tumor prevention. The proposed strategy provides a facile and robust method for large-scale and reproducible fabrication of multifunctional nanovaccines with ultrahigh antigen loading efficiency for tumor therapy.An antigen-directed strategy is proposed for facile fabrication of a multifunctional nanovaccine with ultrahigh antigen loading efficiency for immune labeling/tracing, tumor photothermal-immunotherapy, and tumor prevention. The proposed strategy is a facile and robust method for large-scale and reproducible fabrication of multifunctional nanovaccines with ultrahigh antigen loading efficiency for tumor therapy.
      PubDate: 2018-01-10T03:51:28.386265-05:
      DOI: 10.1002/adma.201704408
       
  • Nociceptive Memristor
    • Authors: Yumin Kim; Young Jae Kwon, Dae Eun Kwon, Kyung Jean Yoon, Jung Ho Yoon, Sijung Yoo, Hae Jin Kim, Tae Hyung Park, Jin-Woo Han, Kyung Min Kim, Cheol Seong Hwang
      Abstract: The biomimetic characteristics of the memristor as an electronic synapse and neuron have inspired the advent of new information technology in the neuromorphic computing. The application of the memristors can be extended to the artificial nerves on condition of the presence of electronic receptors which can transfer the external stimuli to the internal nerve system. In this work, nociceptor behaviors are demonstrated from the Pt/HfO2/TiN memristor for the electronic receptors. The device shows four specific nociceptive behaviors; threshold, relaxation, allodynia, and hyperalgesia, according to the strength, duration, and repetition rate of the external stimuli. Such nociceptive behaviors are attributed to the electron trapping/detrapping to/from the traps in the HfO2 layer, where the depth of trap energy level is ≈0.7 eV. Also, the built-in potential by the work function mismatch between the Pt and TiN electrodes induces time-dependent relaxation of trapped electrons, providing the appropriate relaxation behavior. The relaxation time can take from several milliseconds to tens of seconds, which corresponds to the time span of the decay of biosignal. The material-wise evaluation of the electronic nociceptor in comparison with other material, which did not show the desired functionality, Pt/Ti/HfO2/TiN, reveals the importance of careful material design and fabrication.Nociceptor behaviors are demonstrated from a Pt/HfO2/TiN memristor as an electrical nociceptor. The memristor shows the characteristics of allodynia, and hyperalgesia, which are typical behaviors of biological nociceptors. Such nociceptive responses are attributed to the threshold switching and resistance switching of the memristor, which are caused by electron trapping/detrapping to/from the traps in the HfO2 layer.
      PubDate: 2018-01-10T03:51:07.748176-05:
      DOI: 10.1002/adma.201704320
       
  • A Simple Route to Porous Graphene from Carbon Nanodots for Supercapacitor
           Applications
    • Authors: Volker Strauss; Kris Marsh, Matthew D. Kowal, Maher El-Kady, Richard B. Kaner
      Abstract: A facile method to convert biomolecule-based carbon nanodots (CNDs) into high-surface-area 3D-graphene networks with excellent electrochemical properties is presented. Initially, CNDs are synthesized by microwave-assisted thermolysis of citric acid and urea according to previously published protocols. Next, the CNDs are annealed up to 400 °C in a tube furnace in an oxygen-free environment. Finally, films of the thermolyzed CNDs are converted into open porous 3D turbostratic graphene (3D-ts-graphene) networks by irradiation with an infrared laser. Based upon characterizations using scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy, a feasible reaction mechanism for both the thermolysis of the CNDs and the subsequent laser conversion into 3D-ts-graphene is presented. The 3D-ts-graphene networks show excellent morphological properties, such as a hierarchical porous structure and a high surface area, as well as promising electrochemical properties. For example, nearly ideal capacitive behavior with a volumetric capacitance of 27.5 mF L−1 is achieved at a current density of 560 A L−1, which corresponds to an energy density of 24.1 mWh L−1 at a power density of 711 W L−1. Remarkable is the extremely fast charge–discharge cycling rate with a time constant of 3.44 ms.Small-molecule-based carbon nanodots serve as precursors for 3D turbostratic graphene in a simple laser-assisted conversion process. Very high conductivity, high capacitance, and extremely fast charging rates render 3D-ts-graphene an interesting biomass-derived material for supercapacitor applications.
      PubDate: 2018-01-10T03:50:49.498319-05:
      DOI: 10.1002/adma.201704449
       
  • Switching Vertical to Horizontal Graphene Growth Using Faraday
           Cage-Assisted PECVD Approach for High-Performance Transparent Heating
           Device
    • Authors: Yue Qi; Bing Deng, Xiao Guo, Shulin Chen, Jing Gao, Tianran Li, Zhipeng Dou, Haina Ci, Jingyu Sun, Zhaolong Chen, Ruoyu Wang, Lingzhi Cui, Xudong Chen, Ke Chen, Huihui Wang, Sheng Wang, Peng Gao, Mark H. Rummeli, Hailin Peng, Yanfeng Zhang, Zhongfan Liu
      Abstract: Plasma-enhanced chemical vapor deposition (PECVD) is an applicable route to achieve low-temperature growth of graphene, typically shaped like vertical nanowalls. However, for transparent electronic applications, the rich exposed edges and high specific surface area of vertical graphene (VG) nanowalls can enhance the carrier scattering and light absorption, resulting in high sheet resistance and low transmittance. Thus, the synthesis of laid-down graphene (LG) is imperative. Here, a Faraday cage is designed to switch graphene growth in PECVD from the vertical to the horizontal direction by weakening ion bombardment and shielding electric field. Consequently, laid-down graphene is synthesized on low-softening-point soda-lime glass (6 cm × 10 cm) at ≈580 °C. This is hardly realized through the conventional PECVD or the thermal chemical vapor deposition methods with the necessity of high growth temperature (1000 °C–1600 °C). Laid-down graphene glass has higher transparency, lower sheet resistance, and much improved macroscopic uniformity when compare to its vertical graphene counterpart and it performs better in transparent heating devices. This will inspire the next-generation applications in low-cost transparent electronics.A Faraday cage switches graphene growth in plasma-enhanced chemical vapor deposition (PECVD) from the vertical to the horizontal direction. Laid-down graphene is synthesized on low-softening-point soda-lime glass at ≈580 °C. This is difficult to realize using conventional PECVD or thermal CVD methods. The graphene glass shows advanced defrosting performance in transparent heating devices.
      PubDate: 2018-01-10T03:46:18.065765-05:
      DOI: 10.1002/adma.201704839
       
  • Thioether–Polyglycidol as Multivalent and Multifunctional Coating System
           for Gold Nanoparticles
    • Authors: Susanne Feineis; Johanna Lutz, Lora Heffele, Elmar Endl, Krystyna Albrecht, Jürgen Groll
      Abstract: Thiofunctional polymers are the established standard for the coating and biofunctionalization of gold nanoparticles (AuNPs). However, the nucleophilic and oxidative character of thiols provokes polymeric crosslinking and significantly limits the chemical possibilities to introduce biological functions. Thioethers represent a chemically more stable potential alternative to thiols that would offer easier functionalization, yet a few studies in the literature report inconclusive data regarding the efficacy of thioethers to stabilize AuNPs in comparison to thiols. A systematic comparison is presented of mono- versus multivalent thiol- and thioether-functional polymers, poly(ethylene glycol) versus side chain functional poly(glycidol) (PG) and it is shown that coating of AuNPs with multivalent thioether-functional PG leads to superior colloidal stability, even under physiological conditions and after freeze-drying and resuspension, as compared to thiol analogs at comparable polymer surface coverages. In addition, it is shown that a wide range of functional groups can be introduced in these polymers. Using diazirine functionalization as example, it is demonstrated that proteins can be covalently immobilized, and that conjugation of antibodies via this strategy enables efficient targeting and laser-irradiation induced killing of cells.A strategy for stable and easily modifiable metal particle coatings based on thiol-ene reactive hydrophilic polymers using polyglycidol as an example is presented. It is demonstrated that introducing thioethers along with biofunctional groups, lyophilizable particles that are stable over a wide pH range and in serum can be prepared, and show cell specific targeting through laser induced cell elimination experiments.
      PubDate: 2018-01-10T03:45:44.083808-05:
      DOI: 10.1002/adma.201704972
       
  • Ternary System with Controlled Structure: A New Strategy toward Efficient
           Organic Photovoltaics
    • Authors: Pei Cheng; Rui Wang, Jingshuai Zhu, Wenchao Huang, Sheng-Yung Chang, Lei Meng, Pengyu Sun, Hao-Wen Cheng, Meng Qin, Chenhui Zhu, Xiaowei Zhan, Yang Yang
      Abstract: Recently, a new type of active layer with a ternary system has been developed to further enhance the performance of binary system organic photovoltaics (OPV). In the ternary OPV, almost all active layers are formed by simple ternary blend in solution, which eventually leads to the disordered bulk heterojunction (BHJ) structure after a spin-coating process. There are two main restrictions in this disordered BHJ structure to obtain higher performance OPV. One is the isolated second donor or acceptor domains. The other is the invalid metal–semiconductor contact. Herein, the concept and design of donor/acceptor/acceptor ternary OPV with more controlled structure (C-ternary) is reported. The C-ternary OPV is fabricated by a sequential solution process, in which the second acceptor and donor/acceptor binary blend are sequentially spin-coated. After the device optimization, the power conversion efficiencies (PCEs) of all OPV with C-ternary are enhanced by 14–21% relative to those with the simple ternary blend; the best PCEs are 10.7 and 11.0% for fullerene-based and fullerene-free solar cells, respectively. Moreover, the averaged PCE value of 10.4% for fullerene-free solar cell measured in this study is in great agreement with the certified one of 10.32% obtained from Newport Corporation.The concept and design of ternary organic photovoltaics with a more controlled structure via sequential solution process is reported. The power conversion efficiencies of all four organic photovoltaics (fullerene-based or fullerene-free) with this structure are enhanced by 14–21% relative to those with simple ternary blend.
      PubDate: 2018-01-10T03:41:09.839234-05:
      DOI: 10.1002/adma.201705243
       
  • Surpassing 10% Efficiency Benchmark for Nonfullerene Organic Solar Cells
           by Scalable Coating in Air from Single Nonhalogenated Solvent
    • Authors: Long Ye; Yuan Xiong, Qianqian Zhang, Sunsun Li, Cheng Wang, Zhang Jiang, Jianhui Hou, Wei You, Harald Ade
      Abstract: The commercialization of nonfullerene organic solar cells (OSCs) critically relies on the response under typical operating conditions (for instance, temperature and humidity) and the ability of scale-up. Despite the rapid increase in power conversion efficiency (PCE) of spin-coated devices fabricated in a protective atmosphere, the efficiencies of printed nonfullerene OSC devices by blade coating are still lower than 6%. This slow progress significantly limits the practical printing of high-performance nonfullerene OSCs. Here, a new and relatively stable nonfullerene combination is introduced by pairing the nonfluorinated acceptor IT-M with the polymeric donor FTAZ. Over 12% efficiency can be achieved in spin-coated FTAZ:IT-M devices using a single halogen-free solvent. More importantly, chlorine-free, blade coating of FTAZ:IT-M in air is able to yield a PCE of nearly 11% despite a humidity of ≈50%. X-ray scattering results reveal that large π–π coherence length, high degree of face-on orientation with respect to the substrate, and small domain spacing of ≈20 nm are closely correlated with such high device performance. The material system and approach yield the highest reported performance for nonfullerene OSC devices by a coating technique approximating scalable fabrication methods and hold great promise for the development of low-cost, low-toxicity, and high-efficiency OSCs by high-throughput production.A new nonfullerene combination composed of a high-performance polymer and a nonfluorinated small molecule is presented. It holds great potential for additive-free and halogen-free processing. Small and pure domains and face-on molecular packing collectively enable the first demonstration of ≈11% efficiency air-processed and stable nonfullerene solar cells by blade-coating techniques. Additionally, complete solvent–morphology–performance relations are established for further improvements.
      PubDate: 2018-01-10T03:38:24.92469-05:0
      DOI: 10.1002/adma.201705485
       
  • Shape Memory Polymers for Body Motion Energy Harvesting and Self-Powered
           Mechanosensing
    • Authors: Ruiyuan Liu; Xiao Kuang, Jianan Deng, Yi-Cheng Wang, Aurelia C. Wang, Wenbo Ding, Ying-Chih Lai, Jun Chen, Peihong Wang, Zhiqun Lin, H. Jerry Qi, Baoquan Sun, Zhong Lin Wang
      Abstract: Growing demand in portable electronics raises a requirement to electronic devices being stretchable, deformable, and durable, for which functional polymers are ideal choices of materials. Here, the first transformable smart energy harvester and self-powered mechanosensation sensor using shape memory polymers is demonstrated. The device is based on the mechanism of a flexible triboelectric nanogenerator using the thermally triggered shape transformation of organic materials for effectively harvesting mechanical energy. This work paves a new direction for functional polymers, especially in the field of mechanosensation for potential applications in areas such as soft robotics, biomedical devices, and wearable electronics.A shape-memory-polymer-based triboelectric nanogenerator (STENG) is developed to harvest biomechanical energy and detect biomechanical motion. The STENG is able to transform its shape according to different requirements and hold on to a temporary configuration, which can act as an energy harvester as well as a self-powered, wearable, biomechanical sensor.
      PubDate: 2018-01-10T03:37:18.59977-05:0
      DOI: 10.1002/adma.201705195
       
  • Ultrahigh Piezoelectric Properties in Textured (K,Na)NbO3-Based Lead-Free
           Ceramics
    • Authors: Peng Li; Jiwei Zhai, Bo Shen, Shujun Zhang, Xiaolong Li, Fangyuan Zhu, Xingmin Zhang
      Abstract: High-performance lead-free piezoelectric materials are in great demand for next-generation electronic devices to meet the requirement of environmentally sustainable society. Here, ultrahigh piezoelectric properties with piezoelectric coefficients (d33 ≈700 pC N−1, d33* ≈980 pm V−1) and planar electromechanical coupling factor (kp ≈76%) are achieved in highly textured (K,Na)NbO3 (KNN)-based ceramics. The excellent piezoelectric properties can be explained by the strong anisotropic feature, optimized engineered domain configuration in the textured ceramics, and facilitated polarization rotation induced by the intermediate phase. In addition, the nanodomain structures with decreased domain wall energy and increased domain wall mobility also contribute to the ultrahigh piezoelectric properties. This work not only demonstrates the tremendous potential of KNN-based ceramics to replace lead-based piezoelectrics but also provides a good strategy to design high-performance piezoelectrics by controlling appropriate phase and crystallographic orientation.Textured (K,Na)NbO3-based piezoelectric ceramics with ultrahigh piezoelectric properties (d33 ≈700 pC N−1, d33* ≈980 pm V−1, kp ≈76%) are prepared through a template grain growth method. The intrinsic piezoelectric anisotropy, large lattice distortion, the existence of intermediate monoclinic phase and nanodomain structure are considered likely to be responsible for the excellent piezoelectric properties. These results highlight the textured (K,Na)NbO3-based lead-free ceramics for piezoelectric device applications.
      PubDate: 2018-01-10T03:36:09.328132-05:
      DOI: 10.1002/adma.201705171
       
  • A Universal Strategy for Hollow Metal Oxide Nanoparticles Encapsulated
           into B/N Co-Doped Graphitic Nanotubes as High-Performance Lithium-Ion
           Battery Anodes
    • Authors: Hassina Tabassum; Ruqiang Zou, Asif Mahmood, Zibin Liang, Qingfei Wang, Hao Zhang, Song Gao, Chong Qu, Wenhan Guo, Shaojun Guo
      Abstract: Yolk–shell nanostructures have received great attention for boosting the performance of lithium-ion batteries because of their obvious advantages in solving the problems associated with large volume change, low conductivity, and short diffusion path for Li+ ion transport. A universal strategy for making hollow transition metal oxide (TMO) nanoparticles (NPs) encapsulated into B, N co-doped graphitic nanotubes (TMO@BNG (TMO = CoO, Ni2O3, Mn3O4) through combining pyrolysis with an oxidation method is reported herein. The as-made TMO@BNG exhibits the TMO-dependent lithium-ion storage ability, in which CoO@BNG nanotubes exhibit highest lithium-ion storage capacity of 1554 mA h g−1 at the current density of 96 mA g−1, good rate ability (410 mA h g−1 at 1.75 A g−1), and high stability (almost 96% storage capacity retention after 480 cycles). The present work highlights the importance of introducing hollow TMO NPs with thin wall into BNG with large surface area for boosting LIBs in the terms of storage capacity, rate capability, and cycling stability.A universal protocol is demonstrated for the encapsulation of hollow MO (MO = CoO, Ni2O3, Mn3O4) nanoparticles into B and N co-doped graphitic nanotubes for high-capacity long-life lithium-ion battery anodes.
      PubDate: 2018-01-10T03:31:52.178713-05:
      DOI: 10.1002/adma.201705441
       
  • Self-Organized Superlattice and Phase Coexistence inside Thin Film
           Organometal Halide Perovskite
    • Authors: Tae Woong Kim; Satoshi Uchida, Tomonori Matsushita, Ludmila Cojocaru, Ryota Jono, Kohei Kimura, Daiki Matsubara, Manabu Shirai, Katsuji Ito, Hiroaki Matsumoto, Takashi Kondo, Hiroshi Segawa
      Abstract: Organometal halide perovskites have attracted widespread attention as the most favorable prospective material for photovoltaic technology because of their high photoinduced charge separation and carrier transport performance. However, the microstructural aspects within the organometal halide perovskite are still unknown, even though it belongs to a crystal system. Here direct observation of the microstructure of the thin film organometal halide perovskite using transmission electron microscopy is reported. Unlike previous reports claiming each phase of the organometal halide perovskite solely exists at a given temperature range, it is identified that the tetragonal and cubic phases coexist at room temperature, and it is confirmed that superlattices composed of a mixture of tetragonal and cubic phases are self-organized without a compositional change. The organometal halide perovskite self-adjusts the configuration of phases and automatically organizes a buffer layer at boundaries by introducing a superlattice. This report shows the fundamental crystallographic information for the organometal halide perovskite and demonstrates new possibilities as promising materials for various applications.Coexistence of cubic and tetragonal phases at room temperature and the existence of self-assembled superlattices are confirmed in organometal halide perovskite by transmission electron microscopy. The superlattices are composed of a mixture of tetragonal and cubic phases without compositional change. Based on the phase coexistence and the superlattices, the organometal halide perovskite self-adjusts its microstructural configuration.
      PubDate: 2018-01-10T02:26:29.595319-05:
      DOI: 10.1002/adma.201705230
       
  • Ballistic Jumping Drops on Superhydrophobic Surfaces via Electrostatic
           Manipulation
    • Authors: Ning Li; Lei Wu, Cunlong Yu, Haoyu Dai, Ting Wang, Zhichao Dong, Lei Jiang
      Abstract: The ballistic ejection of liquid drops by electrostatic manipulating has both fundamental and practical implications, from raindrops in thunderclouds to self-cleaning, anti-icing, condensation, and heat transfer enhancements. In this paper, the ballistic jumping behavior of liquid drops from a superhydrophobic surface is investigated. Powered by the repulsion of the same kind of charges, water drops can jump from the surface. The electrostatic acting time for the jumping of a microliter supercooled drop only takes several milliseconds, even shorter than the time for icing. In addition, one can control the ballistic jumping direction precisely by the relative position above the electrostatic field. The approach offers a facile method that can be used to manipulate the ballistic drop jumping via an electrostatic field, opening the possibility of energy efficient drop detaching techniques in various applications.An electrostatic manipulation method is devised to control the ballistic jumping of water drops in determined directions. The liquid detachment from a superhydrophobic surface can be finished within milliseconds, even facilitating the separation of supercooled water before icing. Water drops can also circle superhydrophobic tubes in an energy efficient way. These new findings provide opportunities for self-cleaning, thermal, and anti-icing applications.
      PubDate: 2018-01-09T02:36:58.827993-05:
      DOI: 10.1002/adma.201703838
       
  • Adamantyl Substitution Strategy for Realizing Solution-Processable
           Thermally Stable Deep-Blue Thermally Activated Delayed Fluorescence
           Materials
    • Authors: Yoshimasa Wada; Shosei Kubo, Hironori Kaji
      Abstract: Highly efficient solution-processable emitters, especially deep-blue emitters, are greatly desired to develop low-cost and low-energy-consumption organic light-emitting diodes (OLEDs). A recently developed class of potentially metal-free emitters, thermally activated delayed fluorescence (TADF) materials, are promising candidates, but solution-processable TADF materials with efficient blue emissions are not well investigated. In this study, first the requirements for the design of efficient deep-blue TADF materials are clarified, on the basis of which, adamantyl-substituted TADF molecules are developed. The substitution not only endows high solubility and excellent thermal stability but also has a critical impact on the molecular orbitals, by pushing up the lowest unoccupied molecular orbital energy and triplet energy of the molecules. In the application to OLEDs, an external quantum efficiency (EQE) of 22.1% with blue emission having Commission Internationale de l'Eclairage (CIE) coordinates of (0.15, 0.19) is realized. A much deeper blue emission with CIE (0.15, 0.13) is also achieved, with an EQE of 11.2%. These efficiencies are the best yet among solution-processed TADF OLEDs of CIE y < 0.20 and y < 0.15, as far as known. This work demonstrates the validity of adamantyl substitution and paves a pathway for straightforward realization of solution-processable efficient deep-blue TADF emitters.An adamantyl substitution strategy for designing solution-processable deep-blue thermally activated delayed fluorescence (TADF) emitters is described. Adamantyl fragments are introduced to organic molecular frameworks. The substitution not only endows thermal stability and solubility but also enables control of frontier orbitals and triplet energies, which are critical modifications to realize deep-blue TADF emission with high external quantum efficiencies.
      PubDate: 2018-01-09T02:30:57.637035-05:
      DOI: 10.1002/adma.201705641
       
  • An Alkylated Indacenodithieno[3,2-b]thiophene-Based Nonfullerene Acceptor
           with High Crystallinity Exhibiting Single Junction Solar Cell Efficiencies
           Greater than 13% with Low Voltage Losses
    • Authors: Zhuping Fei; Flurin D. Eisner, Xuechen Jiao, Mohammed Azzouzi, Jason A. Röhr, Yang Han, Munazza Shahid, Anthony S. R. Chesman, Christopher D. Easton, Christopher R. McNeill, Thomas D. Anthopoulos, Jenny Nelson, Martin Heeney
      Abstract: A new synthetic route, to prepare an alkylated indacenodithieno[3,2-b]thiophene-based nonfullerene acceptor (C8-ITIC), is reported. Compared to the reported ITIC with phenylalkyl side chains, the new acceptor C8-ITIC exhibits a reduction in the optical band gap, higher absorptivity, and an increased propensity to crystallize. Accordingly, blends with the donor polymer PBDB-T exhibit a power conversion efficiency (PCE) up to 12.4%. Further improvements in efficiency are found upon backbone fluorination of the donor polymer to afford the novel material PFBDB-T. The resulting blend with C8-ITIC shows an impressive PCE up to 13.2% as a result of the higher open-circuit voltage. Electroluminescence studies demonstrate that backbone fluorination reduces the energy loss of the blends, with PFBDB-T/C8-ITIC-based cells exhibiting a small energy loss of 0.6 eV combined with a high JSC of 19.6 mA cm−2.The synthesis of a novel alkylated indacenodithioeno[3,2-b]thiophene (C8-IDTT) based nonfullerene acceptor (C8-ITIC), is reported. Compared to ITIC with phenylalkyl side chains, the acceptor exhibits a redshifted absorption with increased absorptivity. Solar cell power conversion efficiencies (PCEs) of up to 13.2 % are achieved, with the high PCE attributed to the broad absorption, high crystallinity of C8-ITIC and low voltage loss.
      PubDate: 2018-01-09T02:30:43.366768-05:
      DOI: 10.1002/adma.201705209
       
  • Imaging through Nonlinear Metalens Using Second Harmonic Generation
    • Authors: Christian Schlickriede; Naomi Waterman, Bernhard Reineke, Philip Georgi, Guixin Li, Shuang Zhang, Thomas Zentgraf
      Abstract: The abrupt phase change of light at metasurfaces provides high flexibility in wave manipulation without the need for accumulation of propagating phase through dispersive materials. In the linear optical regime, one important application field of metasurfaces is imaging by planar metalenses, which enables device miniaturization and aberration correction compared to conventional optical microlens systems. With the incorporation of nonlinear responses into passive metasurfaces, optical functionalities of metalenses are anticipated to be further enriched, leading to completely new application areas. Here, imaging with nonlinear metalenses that combine the function of an ultrathin planar lens with simultaneous frequency conversion is demonstrated. With such nonlinear metalenses, imaging of objects with near infrared light while the image appears in the second harmonic signal of visible frequency range is experimentally demonstrated. Furthermore, the functionality of these nonlinear metalenses can be modified by switching the handedness of the circularly polarized fundamental wave, leading to either real or virtual nonlinear image formation. Nonlinear metalenses not only enable infrared light imaging through a visible detector but also have the ability to modulate nonlinear optical responses through an ultrathin metasurface device while the fundamental wave remains unaffected, which offers the capability of nonlinear information processing with novel optoelectronic devices.A subwavelength plasmonic metalens is realized that works solely in the nonlinear regime by second harmonic generation, while the fundamental near-infrared wave stays unaffected. Experimental realization of nonlinear imaging verifies real and virtual images formation of real objects at visible wavelengths. This process is not governed by the traditional lens equation but by a modified version of it.
      PubDate: 2018-01-08T05:21:23.869172-05:
      DOI: 10.1002/adma.201703843
       
  • Light-Emitting Transition Metal Dichalcogenide Monolayers under Cellular
           Digestion
    • Authors: Yin-Ting Yeh; Yi Tang, Zhong Lin, Kazunori Fujisawa, Yu Lei, Yijing Zhou, Christopher Rotella, Ana Laura Elías, Si-Yang Zheng, Yingwei Mao, Zhiwen Liu, Huaguang Lu, Mauricio Terrones
      Abstract: 2D materials cover a wide spectrum of electronic properties. Their applications are extended from electronic, optical, and chemical to biological. In terms of biomedical uses of 2D materials, the interactions between living cells and 2D materials are of paramount importance. However, biointerfacial studies are still in their infancy. This work studies how living organisms interact with transition metal dichalcogenide monolayers. For the first time, cellular digestion of tungsten disulfide (WS2) monolayers is observed. After digestion, cells intake WS2 and become fluorescent. In addition, these light-emitting cells are not only viable, but also able to pass fluorescent signals to their progeny cells after cell division. By combining synthesis of 2D materials and a cell culturing technique, a procedure for monitoring the interactions between WS2 monolayers and cells is developed. These observations open up new avenues for developing novel cellular labeling and imaging approaches, thus triggering further studies on interactions between 2D materials and living organisms.WS2 monolayers are found to be digested by LMH cells and strongly fluoresce. These light-emitting LMH cells pass this strong fluorescence to progeny cells for at least two generations. This work sheds light on interfacing 2D materials with living organisms utilizing the novel optical properties of semiconducting chalcogenides for next-generation cellular labeling and imaging.
      PubDate: 2018-01-08T05:21:04.643537-05:
      DOI: 10.1002/adma.201703321
       
  • High-Performance Single-Crystalline Perovskite Thin-Film Photodetector
    • Authors: Zhenqian Yang; Yuhao Deng, Xiaowei Zhang, Suo Wang, Huazhou Chen, Sui Yang, Jacob Khurgin, Nicholas X. Fang, Xiang Zhang, Renmin Ma
      Abstract: The best performing modern optoelectronic devices rely on single-crystalline thin-film (SC-TF) semiconductors grown epitaxially. The emerging halide perovskites, which can be synthesized via low-cost solution-based methods, have achieved substantial success in various optoelectronic devices including solar cells, lasers, light-emitting diodes, and photodetectors. However, to date, the performance of these perovskite devices based on polycrystalline thin-film active layers lags behind the epitaxially grown semiconductor devices. Here, a photodetector based on SC-TF perovskite active layer is reported with a record performance of a 50 million gain, 70 GHz gain-bandwidth product, and a 100-photon level detection limit at 180 Hz modulation bandwidth, which as far as we know are the highest values among all the reported perovskite photodetectors. The superior performance of the device originates from replacing polycrystalline thin film by a thickness-optimized SC-TF with much higher mobility and longer recombination time. The results indicate that high-performance perovskite devices based on SC-TF may become competitive in modern optoelectronics.Improvement of optoelectronic device performance by using a single-crystalline perovskite thin film is demonstrated by a photodetector. The simultaneously optimized perovskites thickness and crystallinity lead to a record detector performance of a 70 GHz gain-bandwidth product and a 200-photon detection limit.
      PubDate: 2018-01-08T05:20:38.300185-05:
      DOI: 10.1002/adma.201704333
       
  • Toxic Reactive Oxygen Species Enhanced Synergistic Combination Therapy by
           Self-Assembled Metal-Phenolic Network Nanoparticles
    • Authors: Yunlu Dai; Zhen Yang, Siyuan Cheng, Zhongliang Wang, Ruili Zhang, Guizhi Zhu, Zhantong Wang, Bryant C. Yung, Rui Tian, Orit Jacobson, Can Xu, Qianqian Ni, Jibin Song, Xiaolian Sun, Gang Niu, Xiaoyuan Chen
      Abstract: Engineering functional nanomaterials with high therapeutic efficacy and minimum side effects has increasingly become a promising strategy for cancer treatment. Herein, a reactive oxygen species (ROS) enhanced combination chemotherapy platform is designed via a biocompatible metal-polyphenol networks self-assembly process by encapsulating doxorubicin (DOX) and platinum prodrugs in nanoparticles. Both DOX and platinum drugs can activate nicotinamide adenine dinucleotide phosphate oxidases, generating superoxide radicals (O2•−). The superoxide dismutase-like activity of polyphenols can catalyze H2O2 generation from O2•−. Finally, the highly toxic HO• free radicals are generated by a Fenton reaction. The ROS HO• can synergize the chemotherapy by a cascade of bioreactions. Positron emission tomography imaging of 89Zr-labeled as-prepared DOX@Pt prodrug Fe3+ nanoparticles (DPPF NPs) shows prolonged blood circulation and high tumor accumulation. Furthermore, the DPPF NPs can effectively inhibit tumor growth and reduce the side effects of anticancer drugs. This study establishes a novel ROS promoted synergistic nanomedicine platform for cancer therapy.A self-assembled reactive oxygen species (ROS)-promoting combination drug-delivery platform based on metal–polyphenol networks is designed by encapsulating doxorubicin and platinum prodrugs in nanoparticles. The nanoparticles exhibit excellent tumor inhibition and long survival time due to the high tumor accumulation and ROS enhances chemotherapy by cascade bioreactions in cancer cells.
      PubDate: 2018-01-08T04:01:56.800503-05:
      DOI: 10.1002/adma.201704877
       
  • Engineered Transport in Microporous Materials and Membranes for Clean
           Energy Technologies
    • Authors: Changyi Li; Stephen M. Meckler, Zachary P. Smith, Jonathan E. Bachman, Lorenzo Maserati, Jeffrey R. Long, Brett A. Helms
      Abstract: Many forward-looking clean-energy technologies hinge on the development of scalable and efficient membrane-based separations. Ongoing investment in the basic research of microporous materials is beginning to pay dividends in membrane technology maturation. Specifically, improvements in membrane selectivity, permeability, and durability are being leveraged for more efficient carbon capture, desalination, and energy storage, and the market adoption of membranes in those areas appears to be on the horizon. Herein, an overview of the microporous materials chemistry driving advanced membrane development, the clean-energy separations employing them, and the theoretical underpinnings tying membrane performance to membrane structure across multiple length scales is provided. The interplay of pore architecture and chemistry for a given set of analytes emerges as a critical design consideration dictating mass transport outcomes. Opportunities and outstanding challenges in the field are also discussed, including high-flux 2D molecular-sieving membranes, phase-change adsorbents as performance-enhancing components in composite membranes, and the need for quantitative metrologies for understanding mass transport in heterophasic materials and in micropores with unusual chemical interactions with analytes of interest.Recent innovations in microporous membranes, which define state-of-the-art performance across many clean-energy separations, are reviewed. Relevant material classes (e.g., metal–organic frameworks, microporous polymers, etc.), general design principles for pore size and chemical functionality, and applications seeing microporous membrane adoption are discussed. Emergent technologies and related opportunities in this growing field are also examined.
      PubDate: 2018-01-08T03:56:16.500369-05:
      DOI: 10.1002/adma.201704953
       
  • Switching the Proton Conduction in Nanoporous, Crystalline Materials by
           Light
    • Authors: Kai Müller; Julian Helfferich, Fangli Zhao, Rupal Verma, Anemar Bruno Kanj, Velimir Meded, David Bléger, Wolfgang Wenzel, Lars Heinke
      Abstract: Proton conducting nanoporous materials attract substantial attention with respect to applications in fuel cells, supercapacitors, chemical sensors, and information processing devices inspired by biological systems. Here, a crystalline, nanoporous material which offers dynamic remote-control over the proton conduction is presented. This is realized by using surface-mounted metal–organic frameworks (SURMOFs) with azobenzene side groups that can undergo light-induced reversible isomerization between the stable trans and cis states. The trans–cis photoisomerization results in the modulation of the interaction between MOF and guest molecules, 1,4-butanediol and 1,2,3-triazole; enabling the switching between the states with significantly increased (trans) and reduced (cis) conductivity. Quantum chemical calculations show that the trans-to-cis isomerization results in the formation of stronger hydrogen bridges of the guest molecules with the azo groups, causing stronger bonding of the guest molecules and, as a result, smaller proton conductivity. It is foreseen that photoswitchable proton-conducting materials may find its application in advanced, remote-controllable chemical sensors, and a variety of devices based on the conductivity of protons or other charged molecules, which can be interfaced with biological systems.A nanoporous, crystalline material is presented where the proton-conduction of the guest molecules can be switched between high and low conductivity. This is realized by metal–organic frameworks with azobenzene side groups that undergo light-induced reversible isomerization between stable trans and cis states, resulting in the modulation of the host–guest interaction and the control of their conduction properties.
      PubDate: 2018-01-08T03:51:57.147873-05:
      DOI: 10.1002/adma.201706551
       
  • Stirring Up Acceptor Phase and Controlling Morphology via Choosing
           Appropriate Rigid Aryl Rings as Lever Arms in Symmetry-Breaking
           Benzodithiophene for High-Performance Fullerene and Fullerene-Free Polymer
           Solar Cells
    • Authors: Deyu Liu; Junyi Wang, Chunyang Gu, Yonghai Li, Xichang Bao, Renqiang Yang
      Abstract: Two series of new polymers with medium and wide bandgaps to match fullerene (PC71BM) and fullerene-free 3,9-bis(2-methylene-(3-(1,1-dicyanomethylene)-indanone))-5,5,11,11-tetrakis(4-hexylphenyl)-dithieno[2,3-d:2′,3′-d′]-s-indaceno[1,2-b:5,6-b′]dithiophene (ITIC) acceptors are designed and synthesized, respectively. For constructing the key donor building blocks, the effective symmetry-breaking strategy is employed. Two common aromatic rings (thiophene and benzene) are chosen as one side substituted groups in the asymmetric benzodithiophene (BDT) monomers. In addition, another rigid benzene ring is inserted between aryl and thioether in the side chains, which results in larger twisting and destroying the aggregation and forming longer lever arms. As a result, highly ordered polymers (PBDTsTh-FBT and PBDTsPh-FBT) with strong aggregation properties can blend well with roughly spherical PC71BM, while amorphous polymers (PBDTsThPh-BDD and PBDTsPhPh-BDD) with long and rigid aryl rings show good miscibility with elongated ITIC, and finally, both devices exhibit excellent power conversion efficiencies over 10%. Thus, it clearly shows that the asymmetric BDT unit is an excellent donor building block to construct highly efficient photovoltaic polymers. Meanwhile, this work demonstrates that it is not necessary that high-performance fullerene-free polymer solar cells (PSCs) require highly ordered microstructures in the blending films, different from the fullerene-based PSCs.Two series of new asymmetric benzodithiophene building block based polymers with medium and wide bandgaps to match fullerene and fullerene-free acceptors are designed and synthesized, respectively. The significant function of the benzene rings in controlling morphology is revealed, which would be a promising strategy to further design prospective light-harvesting polymers for high-performance polymer solar cells.
      PubDate: 2018-01-08T03:51:07.85394-05:0
      DOI: 10.1002/adma.201705870
       
  • Coupling Mechanical and Electrical Properties in Spin Crossover Polymer
           Composites
    • Authors: Sylvain Rat; Mario Piedrahita-Bello, Lionel Salmon, Gábor Molnár, Philippe Demont, Azzedine Bousseksou
      Abstract: Spin crossover particles of formula [Fe{(Htrz)2(trz)}0.9(NH2-trz)0.3](BF4)1.1 and average size of 20 nm ± 8 nm are homogeneously dispersed in poly(vinylidene fluoride-co-trifluoro-ethylene), P(VDF-TrFE), and poly(vinylidene fluoride) (PVDF) matrices to form macroscopic (cm-scale), freestanding, and flexible nanocomposite materials. The composites exhibit concomitant thermal expansion and discharge current peaks on cycling around the spin transition temperatures, i.e., new “product properties” resulting from the synergy between the particles and the matrix. Poling the P(VDF-TrFE) (70–30 mol%) samples loaded with 25 wt% of particles in 18 MV m−1 electric field results in a piezoelectric coefficient d33 = −3.3 pC N−1. The poled samples display substantially amplified discharges and altered spin transition properties. Analysis of mechanical and dielectric properties reveals that both strain (1%) and permittivity (40%) changes in the composite accompany the spin transition in the particles, giving direct evidence for strong electromechanical couplings between the components. These results provide a novel route for the deployment of molecular spin crossover materials as actuators in artificial muscles and generators in thermal energy harvesting devices.P(VDFTrFE) and poly(vinylidene fluoride) (PVDF) composites of spin transition nanoparticles are synthesized to obtain flexible, freestanding, macroscopic objects displaying original electromechanical properties. The synergy between the components leads to concomitant thermal expansion and electrical discharge peaks at the spin transition providing scope for the deployment of spin crossover materials as actuators in artificial muscles and generators in thermal-energy-harvesting devices.
      PubDate: 2018-01-08T02:11:05.370058-05:
      DOI: 10.1002/adma.201705275
       
  • Citrate Improves Collagen Mineralization via Interface Wetting: A
           Physicochemical Understanding of Biomineralization Control
    • Authors: Changyu Shao; Ruibo Zhao, Shuqin Jiang, Shasha Yao, Zhifang Wu, Biao Jin, Yuling Yang, Haihua Pan, Ruikang Tang
      Abstract: Biological hard tissues such as bones always contain extremely high levels of citrate, which is believed to play an important role in bone formation as well as in osteoporosis treatments. However, its mechanism on biomineralization is not elucidated. Here, it is found that the adsorbed citrate molecules on collagen fibrils can significantly reduce the interfacial energy between the biological matrix and the amorphous calcium phosphate precursor to enhance their wetting effect at the early biomineralization stage, sequentially facilitating the intrafibrillar formation of hydroxyapatite to produce an inorganic–organic composite. It is demonstrated experimentally that only collagen fibrils containing ≈8.2 wt% of bound citrate (close to the level in biological bone) can reach the full mineralization as those in natural bones. The effect of citrate on the promotion of the collagen mineralization degree is also confirmed by in vitro dentin repair. This finding demonstrates the importance of interfacial controls in biomineralization and more generally, provides a physicochemical view about the regulation effect of small biomolecules on the biomineralization front.A high level of citrate-pretreated collagen fibrils can significantly reduce the interfacial energy between the biological matrix and amorphous calcium phosphate precursors at the early mineralization stage, which sequentially facilitates intrafibrillar mineralization and produces an inorganic–organic composite using a wetting effect. This finding demonstrates the importance of interfacial controls in biomineralization.
      PubDate: 2018-01-08T02:01:47.420624-05:
      DOI: 10.1002/adma.201704876
       
  • Light-Responsive Biodegradable Nanorattles for Cancer Theranostics
    • Authors: Chunxiao Li; Yifan Zhang, Zhiming Li, Enci Mei, Jing Lin, Fan Li, Cunguo Chen, Xialing Qing, Liyue Hou, Lingling Xiong, Hui Hao, Yun Yang, Peng Huang
      Abstract: Cancer nanotheranostics, integrating both diagnostic and therapeutic functions into nanoscale agents, are advanced solutions for cancer management. Herein, a light-responsive biodegradable nanorattle-based perfluoropentane-(PFP)-filled mesoporous-silica-film-coated gold nanorod (GNR@SiO2-PFP) is strategically designed and prepared for enhanced ultrasound (US)/photoacoustic (PA) dual-modality imaging guided photothermal therapy of melanoma. The as-prepared nanorattles are composed of a thin mesoporous silica film as the shell, which endows the nanoplatform with flexible morphology and excellent biodegradability, as well as large cavity for PFP filling. Upon 808 nm laser irradiation, the loaded PFP will undergo a liquid–gas phase transition due to the heat generation from GNRs, thus generating nanobubbles followed by the coalescence into microbubbles. The conversion of nanobubbles to microbubbles can improve the intratumoral permeation and retention in nonmicrovascular tissue, as well as enhance the tumor-targeted US imaging signals. This nanotheranostic platform exhibits excellent biocompatibility and biodegradability, distinct gas bubbling phenomenon, good US/PA imaging contrast, and remarkable photothermal efficiency. The results demonstrate that the GNR@SiO2-PFP nanorattles hold great potential for cancer nanotheranostics.A cancer-theranostic nanorattle with excellent uniformity, biocompatibility, and biodegradability is prepared. Light-responsive nanobubble generation allows ultrasound/photoacoustic dual-modality imaging-guided photothermal therapy of melanoma.
      PubDate: 2017-12-22T06:34:35.474861-05:
      DOI: 10.1002/adma.201706150
       
  • Photoactuated Pens for Molecular Printing
    • Authors: Zhongjie Huang; Le Li, Xu A. Zhang, Nourin Alsharif, Xiaojian Wu, Zhiwei Peng, Xiyuan Cheng, Peng Wang, Keith A. Brown, YuHuang Wang
      Abstract: The photoactuation of pen arrays made of polydimethylsiloxane carbon nanotube composites is explored, and the first demonstration of photoactuated pens for molecular printing is reported. Photoactuation of these composites is characterized using atomic force microscopy and found to produce microscale motion in response to modest illumination, with an actuation efficiency as high as 200 nm mW−1 on the sub-1 s time scale. Arrays of composite pens are synthesized and it is found that local illumination is capable of moving selected pens by more than 3 µm out of the plane, bringing them into contact to perform controllable and high quality printing while completely shutting off the nonilluminated counterparts. In light of the scalability limitations of nanolithography, this work presents an important step and paves the way for arbitrary control of individual pens in massive arrays. As an example of a scalable soft actuator, this approach can also aid progress in other fields such as soft robotics and microfluidics.Photoactuated pens are demonstrated from poly(dimethylsiloxane)-carbon nanotube composites and used to perform molecular printing. Upon modest light irradiation, the pens can expand out of plane by more than three micrometers. The photoactuation is rapid, energy efficient, and highly reversible.
      PubDate: 2017-12-22T06:21:02.50145-05:0
      DOI: 10.1002/adma.201705303
       
  • Polymer Encapsulants Incorporating Light-Guiding Architectures to Increase
           Optical Energy Conversion in Solar Cells
    • Authors: Saeid Biria; Fu Hao Chen, Shreyas Pathreeker, Ian D. Hosein
      Abstract: The fabrication of a new type of solar cell encapsulation architecture comprising a periodic array of step-index waveguides is reported. The materials are fabricated through patterning with light in a photoreactive binary blend of crosslinking acrylate and urethane, wherein phase separation induces the spontaneous, directed formation of broadband, cylindrical waveguides. This microstructured material efficiently collects and transmits optical energy over a wide range of entry angles. Silicon solar cells comprising this encapsulation architecture show greater total external quantum efficiencies and enhanced wide-angle light capture and conversion. This is a rapid, straightforward, and scalable approach to process light-collecting structures, whereby significant increases in cell performance may be achieved.Broadband waveguide array architectures are inscribed into polymer films as a new encapsulant material for solar cells. The architectures are grown in a binary-component, photocurable resin through light-induced self-writing, which elicits spontaneous formation of the core–cladding waveguide profile. Their light-collecting and light-guiding functions are inherited by the film, thereby enabling large-scale enhanced and wide-angle optical energy collection and conversion.
      PubDate: 2017-12-22T06:16:15.305661-05:
      DOI: 10.1002/adma.201705382
       
  • Piecewise Phototuning of Self-Organized Helical Superstructures
    • Authors: Lang Qin; Wei Gu, Jia Wei, Yanlei Yu
      Abstract: Cholesteric liquid crystals (CLCs) exhibit selective reflection that can be tuned owing to the dynamic control of inherent self-organized helical superstructures. Although phototunable reflection is reported, these systems hitherto suffer from a limitation in that the tuning range is restricted to one narrow period and the optically addressed images have to sacrifice one color in the visible spectrum to serve as the background, resulting from the insufficient variation in helical twisting power of existing photoresponsive chiral switches that are all bistable. Here, delicate patterns of three primary red, green, and blue (RGB) colors with a black background are presented, which is realized based on piecewise reflection tuning of the CLC induced by a newly designed photoresponsive tristable chiral switch. Three stable configurations of the chiral switch endow the CLC with two continuous and adjacent tuning periods of the reflection, covering not only entire visible spectrum, but also one more wide period within near-infrared region. Therefore, the concept of piecewise tuning in CLC system demonstrates a new strategy for phototunable RGB and black reflective display.A photoresponsive tristable chiral switch is constructed by incorporating two different azobenzenes into one chiral structure. Three stable configurations of the chiral switch endow the cholesteric liquid crystals with two tuning periods of the reflection, including the period in the visible spectrum and one more period within the near-infrared region, which provides piecewise phototuning of self-organized helical superstructures.
      PubDate: 2017-12-19T05:50:51.846674-05:
      DOI: 10.1002/adma.201704941
       
 
 
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