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ENGINEERING (1201 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Full-text available via subscription   (Followers: 5)
AASRI Procedia     Open Access   (Followers: 14)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 207)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 1)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 10)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 4)
Advanced Science     Open Access   (Followers: 4)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 4)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 6)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Artificial Neural Systems     Open Access   (Followers: 3)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 25)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 14)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 9)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 18)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 22)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 7)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 28)
Advances in Operations Research     Open Access   (Followers: 11)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 13)
Advances in Polymer Science     Hybrid Journal   (Followers: 40)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Remote Sensing     Open Access   (Followers: 34)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 1)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 4)
AIChE Journal     Hybrid Journal   (Followers: 28)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access  
Alexandria Engineering Journal     Open Access  
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 7)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 5)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 4)
Applied Sciences     Open Access   (Followers: 3)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal  
ASEE Prism     Full-text available via subscription   (Followers: 2)
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 7)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 9)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 7)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 3)
Batteries     Open Access   (Followers: 3)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 24)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 3)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access  
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 8)
Biomedical Engineering     Hybrid Journal   (Followers: 16)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 31)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 1)
Biotechnology Progress     Hybrid Journal   (Followers: 40)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription  
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 3)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Full-text available via subscription   (Followers: 14)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 40)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 7)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 7)
Catalysis Science and Technology     Free   (Followers: 6)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 5)
CEAS Space Journal     Hybrid Journal  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 4)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 10)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 13)
City, Culture and Society     Hybrid Journal   (Followers: 20)
Clay Minerals     Full-text available via subscription   (Followers: 8)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 10)
Coastal Engineering Journal     Hybrid Journal   (Followers: 3)
Coatings     Open Access   (Followers: 2)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 1)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 13)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 23)
Composite Interfaces     Hybrid Journal   (Followers: 5)
Composite Structures     Hybrid Journal   (Followers: 242)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 175)
Composites Part B : Engineering     Hybrid Journal   (Followers: 215)
Composites Science and Technology     Hybrid Journal   (Followers: 159)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 12)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 17)
Computers & Geosciences     Hybrid Journal   (Followers: 25)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 5)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 4)
Computers and Geotechnics     Hybrid Journal   (Followers: 8)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 25)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 6)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 7)
Control Engineering Practice     Hybrid Journal   (Followers: 40)
Control Theory and Informatics     Open Access   (Followers: 7)
Corrosion Science     Hybrid Journal   (Followers: 24)
CT&F Ciencia, Tecnologia y Futuro     Open Access  
CTheory     Open Access  
Current Applied Physics     Full-text available via subscription   (Followers: 4)

        1 2 3 4 5 6 7 | Last

Journal Cover Current Applied Physics
  [SJR: 0.716]   [H-I: 55]   [4 followers]  Follow
   Full-text available via subscription Subscription journal  (Not entitled to full-text)
   ISSN (Print) 1567-1739
   Published by Elsevier Homepage  [3041 journals]
  • Structurally tunable reflective metamaterial polarization transformer
           based on closed fish-scale structure
    • Abstract: Publication date: Available online 22 March 2017
      Source:Current Applied Physics
      Author(s): Xu Zhang, Zeyong Wei, Yuancheng Fan, Limei Qi
      A reflective metamaterial polarization transformer (RMPT) is proposed with closed fish-scale structure for high efficient cross-polarization reflection. The maximum efficiency of cross-polarization reflection for normal incidence is 97.2%. The RMPT maintains good performance for incident angles up to 25°, and the RMPT is not restricted to a specific polarization state of the incident wave. Furthermore, the designed RMPT shows excellent structural tunability by optimizing the structural parameters, which make it user-friendly.

      PubDate: 2017-03-25T06:05:08Z
  • Effect of ytterbium, gold and aluminum transparent metallic substrates on
           the performance of the Ga2S3 thin film devices
    • Abstract: Publication date: Available online 21 March 2017
      Source:Current Applied Physics
      Author(s): S.R. Alharbi, A.F. Qasrawi
      In the current work, the structural, optical, dielectric and electrical properties of the Ga2S3 thin films which are deposited onto transparent thin Al, Yb and Au metal substrates are characterized by means of transmittance electron microscopy, X-ray diffraction, ultraviolet–visible light spectroscopy and impedance spectroscopy techniques. The effects of the metallic substrates on the crystalline nature, energy band gap and dielectric spectra are also investigated. The modeling of the dielectric spectra allowed determining the effect of the Al, Yb and Au thin layers on the electron scattering time, the plasmon frequency, free electron density and drift mobility. In addition, a Yb/Ga2S3/Au Schottky barrier and Al/Ga2S3/Au back to back Schottky barrier devices (metal-semiconductor-metal (MSM) device) are fabricated and characterized by means of capacitance -voltage characteristics and capacitance and conductance spectra in the frequency range of 10–1800 MHz. While the Schottky barrier device displayed three distinct positions of resonance-antiresonance phenomena, the MSM device displayed one peak with narrow bandwidth of 10 MHz. The MSM devices exhibited an inversion, depletion and accumulation modes within a voltage range of 0.25 V width at 250 MHz. The study indicates the applicability of these device as smart capacitive switches, as Plasmon devices and as wavetraps.

      PubDate: 2017-03-25T06:05:08Z
  • Growth and characterization of single InGaN quantum well in nonpolar
           a-plane (112¯0) InGaN/GaN light-emitting diodes
    • Abstract: Publication date: Available online 20 March 2017
      Source:Current Applied Physics
      Author(s): Kyuhyun Bang, Sukkoo Jung, Kwang Hyeon Baik, Jae-Min Myoung
      We studied the In incorporation efficiency and composition distribution in a nonpolar a-plane InGaN (a-InGaN) quantum well (QW) layer. The In compositions decreased with increasing growth temperatures due to increased In desorption from InGaN surfaces. It was clear that the In incorporation efficiency on a nonpolar GaN surface is lower than that on a polar c-plane GaN. In addition, the In incorporation rate on an a-InGaN layer could be increased by decreasing the V/III ratio without lowering the growth temperature. In the case of the a-InGaN layer, a composition pulling effect was also observed, suggesting that the In composition of the a-InGaN layer increases along the normal growth direction from the bottom to the top of the InGaN QW layer. Using high-resolution XRD 2θ-ω scans, we found that there existed convex graded In compositions ranging from 4 to 12.7% in an a-InGaN QW layer along the growth direction. No wavelength shift with a current injection of 20–100 mA confirmed the absence of a polarization field. The shift in the electroluminescence (EL) peak energy was ∼11 meV between the electric field parallel and perpendicular to the c-axis components, which was caused by the valence band splitting due to the in-plane compressive strain of the 10 nm a-InGaN QW layer. The EL polarization anisotropy was clearly observed with a polarization ratio of 55%.

      PubDate: 2017-03-25T06:05:08Z
  • Electrochemical properties of TiO2-metal oxide composites for
           dye-sensitized solar cell
    • Abstract: Publication date: Available online 18 March 2017
      Source:Current Applied Physics
      Author(s): Hyeong Ryeol Baek, Ik Soo Eo
      The several types of nanofibers were added in dye-sensitized solar cells (DSSCs) and there electrochemical properties were investigated. The surface morphologies of TiO2 electrode was studied by field emission scanning electron microscopy (FE-SEM) and the photoelectrochemical properties of the DSSCs were measured by photovoltaic-current density, AC impedance. By adding the several types of nanofibers we successfully increased the amount of dye loading and enhance the solar conversion efficiency. The pure TiO2 film based DSSC was obtained solar conversion efficiency of 4.8% under irradiation of AM 1.5 (100 mWcm−2). The solar energy conversion efficiency of TiO2 film with 5 wt% SiO2 fiber is 6.2% and it's higher than another fiber (ZrO2, Al2O3 and TiO2). The V oc , J sc , and FF are 0.73 V, 14.23 mA cm−2 and 60%, respectively.

      PubDate: 2017-03-25T06:05:08Z
  • High-Tc superconductivity from an atomic point of view via tunneling
    • Abstract: Publication date: Available online 18 March 2017
      Source:Current Applied Physics
      Author(s): Jung Hoon Yoo, Jinho Lee
      Even after 30 years of discovery of the high temperature superconductivity (HTSC) from the cuprate compounds by Bednorz and Müller, the mechanism of the formation of Cooper pairs well above the liquid nitrogen boiling temperature is still remained to be elucidated. The discovery of a yet another HTSC family of the iron-based superconductors seemed to add more complexity to this puzzle, but also seems to render a prospect of finding a universal principle shared by the entire HTSC family. The tunneling experiments, on the other hand, also witnessed remarkable breakthroughs ever since Giaever succeeded the first tunneling experiment on a superconducting aluminum. The scanning tunneling microscopy (STM) invented by Binnig and Rohrer began to be heavily applied to the research of the condensed matter and became one of the most versatile spectroscopic tools as well as the most powerful microscope available also in the HTSC research field as of today. In this review, we would like to convey a snapshot of the current application of the STM in the research of HTSC, mainly focusing on the studies using the spectroscopic imaging scanning tunneling microscopy (SI-STM) which eventually led to the scanning Josephson tunneling microscopy (SJTM) by which we can visualize the superconducting Cooper pairs in an atomic scale.

      PubDate: 2017-03-25T06:05:08Z
  • Ruthenium doped carbon aerogel with CO2 surface activation for enhanced
           electrochemical capacitance
    • Abstract: Publication date: Available online 18 March 2017
      Source:Current Applied Physics
      Author(s): Ashish Singh, D.K. Kohli, Sushmita Bhartiya, Rashmi Singh, M.K. Singh, P.K. Gupta
      With the aim of enhancement of electrochemical capacitance, CO2 activation of carbon aerogel (CA) prepared by polycondensation of resorcinol with formaldehyde was performed to obtain activated carbon aerogel (ACA) having improved surface area properties. Ruthenium oxide nano-particles were loaded by impregnation method for utilizing pseudo-capacitive property of ruthenium oxide (RuO2) and the effect of activation treatment was studied. RuO2 loading of 20% by weight was accomplished in CA and ACA to synthesize RuO2 doped carbon aerogel (CA/RuO2) and activated carbon aerogel (ACA/RuO2). While the specific capacitance of carbon aerogel improved from 95 to 153 F/g on activation, RuO2 loading further led to enhancement in capacitance and specific capacitance of 308 F/g was obtained for ACA/RuO2. The studies being important for Ru economy, showed the influence of surface area enhancement of base matrix in achieving high specific capacitance.

      PubDate: 2017-03-25T06:05:08Z
  • Enhanced ambipolar charge transport in staggered carbon nanotube
           field-effect transistors for printed complementary-like circuits
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Kang-Jun Baeg, Hee Jin Jeong, Seung Yol Jeong, Joong Tark Han, Geon-Woong Lee
      Semiconducting single-walled carbon nanotubes (semi-SWNTs) are attractive as they can be used enable high-performance nano-electronic devices. We report the enhanced ambipolar charge transport characteristics of the semi-SWNT field-effect transistors (FETs) based on a top-gated staggered device structure. SWNTs were selectively dispersed in non-polar organic solvents and sorted by a π-conjugated polymer wrapping method. The sorted semi-SWNTs solution was used simply to form a well-percolated CNT-network, and the top-gate and bottom-contact FETs showed relatively high and equivalent electron and hole mobilities with very high on/off-current ratios and steep subthreshold slopes. The equivalent ambipolar charge transport behavior of semi-SWNTs was used to demonstrate a reliable complementary-like electronic circuits. The inverters showed a good switching threshold near the ideal point at half the driving bias, high gain, low hysteresis, and stability under repeatable operating conditions. They can thus be broadly applied as a fundamental circuit element in printed and flexible electronics.
      Graphical abstract image

      PubDate: 2017-03-18T09:30:56Z
  • Controlling the distribution of oxygen functionalities on GO and
           utilization of PEDOT:PSS-GO composite as hole injection layer of a
           solution processed blue OLED
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Halide Diker, Gamze Belkıs Durmaz, Hakan Bozkurt, Fatih Yeşil, Canan Varlikli
      Graphene oxide (GO) was synthesis by Tour method. Particle size distribution effects of raw graphite on the resulting structural, morphological, optical and electrical properties of GO samples and their poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) composites are studied for the graphite particle distributions of <150, 45–75 and 25–45 μm. It is determined that particle size of raw graphite have an impact on oxidation degree, the chemical nature of oxygen functional groups on GO and it also affects the lateral size of obtained GO. PEDOT:PSS-GO composites are utilized as hole injection layer (HIL) in a solution process blue organic light emitting diode. Presence of GO caused negative differential resistance (NDR) and NDR intensity was decreased with the decrease in lateral size of GO, increase in the graphite particle size and carboxyl% of obtained GO. All PEDOT:PSS-GO composite based devices presented better performance than the bare PEDOT:PSS based reference device. The maximum luminous and external quantum efficiency values of the device that contain HIL of PEDOT:PSS-GO(150) were more than 40% and 50% higher than that of the reference, respectively. Two folds of increase in these performance values were able to be reached with the concentration optimization of GO/150 in PEDOT:PSS.

      PubDate: 2017-03-18T09:30:56Z
  • Corrigendum to “Low-damage NH3 plasma treatment on SiO2 tunneling oxide
           of chemically-synthesized gold nanoparticle nonvolatile memory” [Curr.
           Appl. Phys. 16 (5) (2016) 605−610]
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Jer-Chyi Wang, Kai-Ping Chang, Chin-Hsiang Liao, Ruey-Dar Chang, Chao-Sung Lai, Li-Chun Chang

      PubDate: 2017-03-18T09:30:56Z
  • Anomalously high dielectric strength and low frequency dielectric
           relaxation of a bent-core liquid crystal with a large kink angle
    • Abstract: Publication date: Available online 16 March 2017
      Source:Current Applied Physics
      Author(s): Anoop Kumar Srivastava, Jongyoon Kim, Sunggu Yeo, Jinyoung Jeong, E-Joon Choi, Vijay Singh, Ji-Hoon Lee
      We investigated the dielectric dispersion property of a bent-core liquid crystal (BLC) with a large kink angle in the frequency range of 1.0 Hz–5.5 MHz in a planar aligned cell. Single dielectric dispersion was observed in the smectic A, nematic, and isotropic phase of the planar aligned sample. The dielectric strengths, relaxation frequencies, distribution parameters, and dc conductivity were measured as a function of temperature. The dielectric strength of the observed relaxation mode was anomalously high (∼70), whereas the relaxation frequency was low at ∼500 Hz. The relaxation mode observed in the planar aligned cell was attributed to the fluctuations in the polarization direction due to the cooperative motion of the molecules.

      PubDate: 2017-03-18T09:30:56Z
  • Prediction of tensile modulus in polymer nanocomposites containing carbon
           nanotubes (CNT) above percolation threshold by modification of
           conventional model
    • Abstract: Publication date: Available online 16 March 2017
      Source:Current Applied Physics
      Author(s): Yasser Zare, Kyong Yop Rhee
      In this paper, a simple model is developed to predict the tensile modulus of polymer/carbon nanotubes (CNT) nanocomposites (PCNT) above percolation threshold. Since the conventional models such as Ouali and Lyngaae-Jorgensen (L-J) cannot predict the accurate results, a developed model is presented which calculates proper modulus as a function of aspect ratio (α) and volume fraction of CNT at percolation threshold ( ϕ p ) . The developed model can present accurate data, which agree with the experimental results at all filler concentrations. The high ranges of “α” and low values of “ ϕ p ” achieve a desirable modulus. However, a high “ ϕ p ” causes the poor modulus at different “α” demonstrating that the role of “α” is highlighted at slight “ ϕ p ”. It is also possible to calculate the “α” and “ ϕ p ” parameters by applying the developed model to the experimental data of modulus.

      PubDate: 2017-03-18T09:30:56Z
  • Multiferroic effect of multilayer low-distorted doped bismuth ferrite thin
           films as a function of sputtering power and crystallographic texture
    • Abstract: Publication date: Available online 16 March 2017
      Source:Current Applied Physics
      Author(s): G. Rojas-George, A. Concha-Balderrama, H. Esparza-Ponce, J.J. Gervacio-Arciniega, M.P. Cruz, V. Orozco-Carmona, A. Reyes-Rojas
      Low-distortion rhombohedral multilayer barium-nickel co-doped BiFeO3 (Bi0.75Ba0.25Fe0.975Ni0.025O3) multiferroic thin films were grown on Pt/TiO2/SiO2/Si substrates by reactive RF magnetron sputtering, as a function of sputtering power. X-ray diffraction showed that Bi0.75Ba0.25Fe0.975Ni0.025O3 multilayer films have a pseudocubic-type structure. Piezoresponse force microscopy demonstrated polarization switching in all films at room temperature. Scanning electron microscopy showed different morphologies depending on the sputtering power used during the deposition process and that the thickness of the film decreases from about 142 nm to 72 nm as the sputtering power decreases. Magnetization results showed that as the thickness of the film decreases, the magnetization of the film increases. Thus, there is a direct relation between the sputtering power, thickness and the magnetization of the film. A direct relation between in-plane residual stress and thin film thickness has been obtained. This causes the main axe of the BO6 octahedra to be tilted from 90 to 45° (from thin-film surface) by a texture crystal volume of 29 and 18% in the (012) and (110) crystallographic planes respectively.
      Graphical abstract image

      PubDate: 2017-03-18T09:30:56Z
  • Emission of CdSe quantum dots according to the capping ligands
    • Abstract: Publication date: Available online 9 March 2017
      Source:Current Applied Physics
      Author(s): Min Jung Lee, Jaewon Lee, Ho-Soon Yang, Kyong-Soo Hong
      Quantum dot nanocrystals have particular optical properties due to the quantum confinement effect and the surface effect. This study focuses on the effects of organic materials capping quantum dot on the emission properties of quantum dots. The quantum dots prepared by using 1-hexadecylamine in the synthesis show strong emission, while the quantum dots prepared by using tri-octylphosphine oxide exhibit a suppressed emission and an extra emission related with the surface energy traps. These organic materials cap the quantum dots and make the surface conditions of quantum dots different. TEM images and X-ray diffraction patterns reveal that 1-hexadecylamine constructs a layer on the surface of quantum dot during the synthesis and this surface passivation by a layer of 1-hexadecylamine reduces the surface energy traps. Differently from 1-hexadecylamine, tri-octylphosphine oxide dangles from the surface, which causes a poorly passivated surface. This generates the surface deep trap levels giving rise to a significant and broad emission in the lower energy regime. The optical mechanism is studied by measuring the emission spectra and the time-resolved spectra at various temperatures from 4 K to 300 K.

      PubDate: 2017-03-18T09:30:56Z
  • Enhancement of a photovoltaic cell performance by a coupled cooled
    • Abstract: Publication date: Available online 9 March 2017
      Source:Current Applied Physics
      Author(s): H. Machrafi
      A new analytical mathematical model is developed, describing a cooled photovoltaic-thermoelectric hybrid system. The thermoelectric material is a nanocomposite where the model takes into account size-dependent non-local thermoelectric properties from an extended thermodynamic point of view. The photovoltaic device powers also the cooling system. The model determines first the optimum thickness of the photovoltaic device, then studies the influence of several size-related parameters on the thermoelectric efficiency (also related to the figure of merit) and finally, coupled to a cooling device, the overall efficiency. For the photovoltaic part, the model is applied to two materials, mono-crystalline and poly-crystalline silicon. The thermoelectric part of the model is applied to an n-leg nanocomposite made out of Sb2Te3 nanoparticles in a Bi2Te3 matrix and of a p-leg nanocomposite made out of Bi2Se3 nanoparticles in a Bi2Te3 matrix. An optimal total photovoltaic device size has been found to be around 127 μm and 1.25 μm for the mono- and poly-crystalline silicon, respectively, leading to efficiencies up to 20%, depending on photovoltaic recombination characteristics. With the cooling device, the overall efficiency was increased by up to an additional 10% (an increase of almost 50%), leading to overall efficiencies around 25%.

      PubDate: 2017-03-18T09:30:56Z
  • Reduction of point defects and Cu surface composition in Cu(In,Ga)Se2 film
           by Se annealing with a NaF overlayer at intermediate temperatures
    • Abstract: Publication date: Available online 8 March 2017
      Source:Current Applied Physics
      Author(s): Suncheul Kim, Young Min Ko, Seung Tae Kim, Yong Woo Choi, Joong Keun Park, Byung Tae Ahn
      Donor-type point defects such as a Se vacancy or cation antisite in Cu(In,Ga)Se2 (CIGS) films were controlled by Se annealing of CIGS film. The photoluminescence intensities originating from such defects were reduced by Se annealing at 300 °C. The short-circuit current of the CIGS solar cell with the Se annealing increased but the fill factor and open-circuit voltage were degraded due to the out-diffusion of Cu from the bulk to the CIGS surface. With a NaF overlayer on the CIGS film the Cu concentration at the CIGS surface was decreased by Se annealing at 300 °C. The literature has demonstrated that the Cu concentration is reduced by applying both NaF and KF together on the CIGS film. However, we found that the application of a NaF overlayer also greatly reduced the Cu concentration at the CIGS surface. In addition, the Na concentration increased greatly at the CIGS surface, forming a desirable surface layer with a lower valence band maximum. As a result, in addition to the increase of short-circuit current, the fill factor and open-circuit voltage increased significantly. The origin of the improvement in cell performance is described by analyzing the point defects from low-temperature photoluminescence, the valence band maximum from x-ray photoelectron spectroscopy, the reverse saturation current from diode curves, and the carrier lifetimes from time-resolved photoluminescence.

      PubDate: 2017-03-18T09:30:56Z
  • Highly ordered copper oxide (Cu2O) nanopillar arrays using template
           assisted electrodeposition technique and their temperature dependent
           electrical characteristics
    • Abstract: Publication date: Available online 7 March 2017
      Source:Current Applied Physics
      Author(s): A. Venkatesan, E.S. Kannan
      Highly ordered Copper Oxide (Cu2O) nanopillars were successfully grown inside the porous anodized alumina (AAO) template by electrodeposition technique. To liberate the AAO template to get the free standing nanopillars, several etching trials were conducted using sodium hydroxide (NaOH) solution of varying concentration (ranging from 1 M to 5 M) and reaction time (8–60 min). On investigating the etched samples using scanning electron microscope, it was found that the sample treated with 1 M NaOH for 60 min yielded AAO template free standing vertically aligned nanopillars. Resistances of these nanopillars were found to be three orders of magnitude greater than the thin film which was used as a control sample. The temperature dependent (180–300 K) current-voltage (I-V) measurement on nanopillars showed non-linear characteristics which was analyzed using back to back schottky diode model and thermionic field emission (TFE) theory. Our calculations revealed that the carrier transport is diffusive (mean free path = 8.9 nm < < length of nanopillars = 4 μm) in nature and the existence of defect sites with activation energies of 0.3 and 0.6 eV which acts as hole traps. This present work demonstrates a reliable technique for realizing vertically aligned Cu2O nanopillars which could find application in solar cell, gas sensors, Li ion batteries, and memory devices.

      PubDate: 2017-03-18T09:30:56Z
  • Enhanced dielectric piezo-/ferro-/electric properties of dye doped sodium
           acid phthalate crystal
    • Abstract: Publication date: Available online 7 March 2017
      Source:Current Applied Physics
      Author(s): Geeta Ray, Sonu Kumar, Nidhi Sinha, Binay Kumar
      Pure and 0.1 mol% amaranth dye doped sodium acid phthalate (SAP) crystals were grown by slow evaporation technique. Doping of the dye resulted in light pink colored crystals without changing its morphology. PXRD revealed no extra peak as a result of doping. The dye doping altered Raman peak intensities due to the presence of organic functional groups. Doped crystals showed the enhanced dielectric constant value ∼170. The dielectric constant showed very small variation with temperature, which is useful in high temperature dielectric and piezoelectric devices. The piezoelectric charge coefficient increased from 1 pC/N to 2 pC/N as a result of dye doping. Ferroelectric P-E loops for the grown crystals were traced at room temperature, which revealed the enhancement in polarization due to dye doping. The hardness parameters and elastic stiffness were found to decrease as a result of dye doping in SAP crystals.
      Graphical abstract image

      PubDate: 2017-03-18T09:30:56Z
  • Silicon carbide (SiC) nanotubes as potential sensors for organophosphate
    • Abstract: Publication date: Available online 7 March 2017
      Source:Current Applied Physics
      Author(s): Keyumars Hassanzadeh, Keivan Akhtari, Bahareh Fakhraei, Ghazal Akhtari, Halaleh Hassanzadeh
      The detection and clean-up of the organophosphate (OP) compounds have special importance for those who work in the field of health and governments due to the bad effects of these compounds on human health. In this paper, we have employed the PBE level of theory and ultrasoft pseudopotentials to investigate the ability of silicon carbide nanotubes (SiCNTs) as sensors for organophosphate detection. We found that the binding energy and charge transfer for adsorption of OP on (6,0) SiCNT represents the formation of a strong bond. However, the ΔE Gap demonstrates the significant changes (12%) in the electronic properties of (10,0) SiC nanotubes which could induce considerable alteration in the SiCNT electrical conductivity. According to the results, the OP can be adsorbed on SiCNT and these types of nanotubes can be promising candidates for detecting organophosphate compounds. The non-equilibrium Green function (NEGF) method shows good performance for the sensor sensitivity.
      Graphical abstract image

      PubDate: 2017-03-18T09:30:56Z
  • Manipulation of magnetization in GaMnAs films by spin-orbit-induced
           magnetic fields
    • Abstract: Publication date: Available online 7 March 2017
      Source:Current Applied Physics
      Author(s): Sangyeop Lee, Taehee Yoo, Seul-Ki Bac, Seonghoon Choi, Hakjoon Lee, Sanghoon Lee, X. Liu, J.K. Furdyna, M. Dobrowolska
      We have investigated the effect of spin-orbit-induced (SOI) magnetic fields on magnetization switching in GaMnAs films. The sign of such SOI fields depends on the direction of the current flowing in the film, thus providing a handle for electrically manipulating magnetization in ferromagnetic GaMnAs films. Specifically, when an applied magnetic field is swept along the current direction, magnetization reversal occurs via rotations in opposite sense (i.e., clockwise (CW) or counterclockwise (CCW)) depending on the sign of the current, thus leading to opposite signs of the planar Hall resistance (PHR) measured on the film. The effect of SOI fields also manifests itself through hysteretic behavior of PHR for two opposite currents as a fixed magnetic field is rotated in the film plane. The width of the resulting hysteresis between two current directions then allows us to estimate the magnitude of the SOI field at current density of 1.0 × 105 A/cm2 as ∼1.2 Oe in our GaMnAs film. Such switching of magnetization between two magnetic easy axes induced by switching the sign of an applied current provides a means of electronically controlling the value of film resistance (in this case of PHR), a process that can be exploited in spintronic devices.

      PubDate: 2017-03-18T09:30:56Z
  • Controlled enzymatic stability and release characteristics of
           supramolecular chiral peptide amphiphile nanofiber gels
    • Abstract: Publication date: Available online 2 March 2017
      Source:Current Applied Physics
      Author(s): Aygul Zengin, Goksu Cinar, Mustafa O. Guler
      Supramolecular bioarchitectures formed by assembly of achiral or chiral building blocks play important roles in various biochemical processes. Stereochemistry of amino acids is important for structural organization of peptide and protein assemblies and structure-microenvironment interactions. In this study, oppositely charged peptide amphiphile (PA) molecules with L-, D- and mixture of L- and D-amino acid conformations are coassembled into supramolecular nanofibers and formed self-supporting gels at pH 7.4 in water. The enzymatic stability of the PA nanofiber gels was studied in the presence of proteinase K enzyme, which digest a broad spectrum of proteins and peptides. The structural changes on the chiral PA nanofibers were also analyzed at different time periods in the presence of enzymatic activity. Controlled release of a model cargo molecule through the chiral PA nanofiber gels was monitored. The diffusivity parameters were measured for all gel systems. Release characteristics and the enzymatic stability of the peptide nanofiber gels were modulated depending on organization of the chiral PA molecules within the supramolecular assemblies.
      Graphical abstract image

      PubDate: 2017-03-05T08:54:54Z
  • Adjust band gap of IATO nanoparticles to obtain desirable optical property
           by one-step hydrothermal oxidation
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Te Hu, Yuchang Su, Ian R. Baxendale, Jiang Tan, Hongbo Tang, Lihua Xiao, Feng Zheng, Ping Ning
      Antimony-tin-doped indium oxide (IATO) as transparent conducting oxide (TCO) exhibits significant optical property on blocking UV and Infrared(IR) for wavelengths less ∼400 nm and over ∼1400 nm as well as appropriate transmissivity on visible wavelength in our work that can be as an optional idea optical material applying in shielding film or nanocomposite to achieve desired optical application. We have successfully developed an optimal synthesis system which allows for a single hydrothermal oxidation directly synthesizing IATO nanoparticles without high-temperature calcination. These nanoparticles show superior size, crystallinity, agglomeration and are free of intermediates In(OH)3 and InOOH. We also have demonstrated they give scope to desired optical property as a result of an altered IATO band gap energy. We highlight this approach due to the shortened preparation time, the reduced energy consumption and the decreased chemical usage which dramatically save on production costs and protect environment.

      PubDate: 2017-02-25T17:05:26Z
  • Strong dependence of photocurrent on illumination-light colors for
           ZnO/graphene Schottky diode
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Hwauk Lee, Namhyun An, Seockjin Jeong, Soonhong Kang, Soonki Kwon, Jisu Lee, Youngmin Lee, Deuk Young Kim, Sejoon Lee
      The ZnO/graphene Schottky diode reveals a strong dependence of its photocurrent on the color of the illuminating lights (i.e., a dependence of photocurrent on the photon energy). As the photon energy increases, the magnitude of photocurrent is exponentially increased. Particularly, in comparison with the red-light illumination, the device clearly exhibits approximately 100-times-increased photocurrent when illuminating the ultra-violet light. We attribute this feature to the increase in photo-excited carriers at the depletion region in ZnO. The results suggest that the ZnO/graphene Schottky diode holds promise for the application in high-performance color-selectable photodetectors.

      PubDate: 2017-02-19T16:55:12Z
  • Tuning electronic, magnetic and optical properties of germanene nanosheet
    • Abstract: Publication date: Available online 14 February 2017
      Source:Current Applied Physics
      Author(s): Namrata Dhar, Arka Bandyopadhyay, Debnarayan Jana
      A first principles based density functional theory (DFT) has been employed to doped free standing (FS) germanene mono-layer by arsenic (As) and gallium (Ga). It has been revealed that electronic, magnetic and optical properties can be tailored by either (a) type, (b) concentration and (c) choosing specific sites of substitutional doping elements or suitable combinations of them. As a result, one can tune the splitting of Dirac cones at or near Dirac K point by proper doping. In particular, similar type doped structures indicate transition from semi-metallic to metallic region. Besides, induced magnetism for double doping in FS germanene can be traced back to the 4p level electrons in spin-polarized projected density of states. Optical property analysis predicts that values of static dielectric constant (ε 1(0)) and refractive index (n(0)) are enhanced significantly than pristine layer by proper doping in case of parallel polarization. Optical conductivity study elucidates the fact that, height of maximum peak is amplified by 5.50% than pristine system for double Ga doping at non-equivalent site. We strongly believe that this investigation of electronic, optical and magnetic properties of doped germanene nanosheet might be useful as a powerful tool for next generation germanene based nano-technology.

      PubDate: 2017-02-19T16:55:12Z
  • Terahertz emission characteristics of GaMnAs dilute magnetic semiconductor
           under 650 mT external magnetic field
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Alexander De Los Reyes, Elizabeth Ann Prieto, Karim Omambac, Jeremy Porquez, Lorenzo Lopez, Karl Cedric Gonzales, John Daniel Vasquez, Mae Agatha Tumanguil, Joselito Muldera, Kohji Yamamoto, Masahiko Tani, Armando Somintac, Elmer Estacio, Arnel Salvador
      We investigate the effects of an externally applied magnetic field on the terahertz (THz) emission of Gallium Manganese Arsenide (GaMnAs) films grown via molecular beam epitaxy (MBE). Results show that low Mn-doping in GaMnAs resulted to increased THz emission as compared with a SI-GaAs substrate. Further increase in Mn-doping content resulted to a comparably less THz emission, which is attributed to reduced crystallinity and higher free-carrier absorption. Under an external magnetic field, the contributions of the B u p and B d o w n -related THz emission were observed to be asymmetric: possibly due to intrinsic magnetic properties of GaMnAs.

      PubDate: 2017-02-12T16:42:50Z
  • Light-extraction enhancement of white LEDs with different phases of
           TiO2:0.01Eu3+ spheres
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Ju Young Mun, Ganji Seeta Rama Raju, Jin Young Park, Hyun Kyoung Yang
      We report the synthesis of TiO2:0.01Eu3+ spheres by a solvothermal reaction method and their utilization in the enhancement of light-extraction efficiency. The light-extraction efficiency was enhanced by increasing the extraction probability of the internal and external reflected photons in the YAG:Ce3+ yellow phosphor based white light-emitting diodes (WLEDs). The crystalline structure of TiO2:0.01Eu3+ spheres was investigated by an X-ray diffraction analysis. The anatase phased TiO2:0.01Eu3+ spheres exhibited a typical red emission under 463.5 nm wavelength. The diffused reflectance spectra displayed higher reflectance for rutile phase and lower for anatase phase. However, compared to the typically, combination of YAG:Ce3+ yellow phosphor and blue LED chip, fabricated WLED, the light-extraction efficiency of WLED was improved to 80% when TiO2: 0.01Eu3+ spheres were mixed with YAG:Ce3+ phosphor in the fabrication process.

      PubDate: 2017-02-12T16:42:50Z
  • ZnSnP2 thin-film solar cell prepared by phosphidation method under
           optimized Zn/Sn atomic ratio of its absorbing layer
    • Abstract: Publication date: Available online 11 February 2017
      Source:Current Applied Physics
      Author(s): Noriyuki Yuzawa, Jakapan Chantana, Shigeru Nakatsuka, Yoshitaro Nose, Takashi Minemoto
      ZnSnP2 film is a promising absorber for thin-film solar cell due to earth-abandant and nontoxic element. Phosphidation method is utilized for the fabrication of ZnSnP2 films with different Zn/Sn atomic ratios. ZnSnP2 film with the large ZnSnP2 protrusions are demonstrated with Zn/Sn of ∼1 (near stoichiometry), while the film with the relatively smooth surface is presented with Zn/Sn of above 1 (Zn rich). According to grazing incidence X-ray diffraction measurement, Sn4P3 secondary phase is appeared in ZnSnP2 film with Zn/Sn of below 1 (Sn rich), whereas Zn3P2 secondary phase is presented in the film with Zn rich. On the other hand, Sn4P3 and Zn3P2 secondary phases are not observed in ZnSnP2 thin film with near stoichiometry, thus leading to the longest carrier lifetime, implied by time-resolved photoluminescence measurement. Ultimately, the conversion efficiency of 0.021% with short-circuit current density of 5.03 mA/cm2 is reported for ZnSnP2 thin-film solar cell, where its absorbing layer possesses single ZnSnP2 phase and Zn/Sn ratio near stoichiometry. The energy bandgap of ZnSnP2 thin films by phosphidation method is estimated to be 1.38 eV by external quantum efficiency, implying that the ZnSnP2 has sphalerite structure.

      PubDate: 2017-02-12T16:42:50Z
  • Numerical investigation of gas heating effect in dielectric barrier
           discharge for Ne-Xe excilamp
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Amar Benmoussa, Ahmed Belasri, Zahir Harrache
      The purpose of this paper is to study the gas heating phenomenon in dielectric barrier discharge (DBD) due to the Joule heating effect for Ne-Xe gas mixtures. In this work, the simulation was performed using a one-dimensional fluid model. The gas temperature profile was calculated by heat conduction equation resolution along gap distance of discharge. The increasing of gas temperature close to the vicinity of cathode is due to the high values in the power deposited in this region. The results show that the gas temperature in DBD excited with rectangular applied voltage waveform is more important than the discharge created by a sinusoidal excitation. For high values of secondary electron emission coefficient (γ) the gas temperature will be increasing. The effect of varying gas mixture composition on gas temperature has been also examined.

      PubDate: 2017-02-06T16:30:32Z
  • Photo-induced charge separation properties of NiO/Bi2O3 heterojuctions
           with efficient simulated solar-driven photocatalytic performance
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Qi Yang, Junbo Zhong, Jianzhang Li, Jiufu Chen, Zhen Xiang, Tao Wang, Minjiao Li
      The inherent drawbacks of Bi2O3 greatly limit the practical application of Bi2O3, thus it is crucial to boost the photocatalytic activity of Bi2O3, and therefore NiO was employed to couple with Bi2O3. In this paper, NiO/Bi2O3 heterostructures with improved sunlight driven -photocatalytic activity were constructed by a pore impregnating method. The samples were studied by Brunauer -Emmett- Teller (BET) method, X-ray diffraction (XRD), UV–Vis diffuse reflectance spectroscopy (DRS), high-resolution transmission electron microscopy (HRTEM), surface photovoltage (SPV) spectroscopy and electron spin-resonance (ESR) spectroscopy. The photocatalytic activities of NiO/Bi2O3 heterostructures toward discoloration of methyl orange (MO) aqueous solutions were evaluated. The results display that the presence of NiO in the heterojuctions increases the specific surface area, the absorbance in the visible light region, the separation rate of the photo-induced charge pairs and the formation of ·O2 − in the photocatalytic system.
      Graphical abstract image

      PubDate: 2017-02-06T16:30:32Z
  • Interface modification of CH3NH3PbI3/PCBM by pre-heat treatment for
           efficiency enhancement of perovskite solar cells
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Sutthipoj Sutthana, Kritsada Hongsith, Pipat Ruankham, Duangmanee Wongratanaphisan, Atcharawon Gardchareon, Surachet Phadungdhitidhada, Dheerawan Boonyawan, Pisist Kumnorkaew, Adisorn Tuantranont, Supab Choopun
      An interfacial modification of CH3NH3PbI3/PCBM is investigated by pre-heating PCBM solution before spin-coating on the CH3NH3PbI3layer.By adjusting PCBM concentration, PCBM films were optimized to form homogeneous films. Besides, the pre-heat treatment of PCBM solution exhibits a better covered area over CH3NH3PbI3 layer with reduced pinhole compared with the non-heat treatment. This can be explained by the higher thermal energy PCBM molecules of the pre-heat solution leading to higher molecule mobility that can reorganizes a structural as well as enhance the diffusion and enhance coverage of PCBM films over CH3NH3PbI3. The optimized cell is enhanced with average power conversion efficiency from 4.59% up to 5.76% (6.44% maximum) by heat treatment. To investigate interface between CH3NH3PbI3 and PCBM, the contact angle was measured and found that the contact angle of PCBM films were higher after heat treatment suggesting re-alignment and better orientation of PCBM on perovskite film. The better orientation of PCBM can be explained in term of hydrophilic/hydrophobic property of the interface between CH3NH3PbI3 and PCBM. These results suggest that pre-heat treatment of PCBM solution has ability to modify the interface for better orientation of PCBM and resulting in efficiency enhancement due to better carrier transport direction at the CH3NH3PbI3/PCBM interfaces for perovskite solar cells. In addition, the better orientation that the head (non-polar)is oriented at outer surface can also prevent the solar cells from surrounding moisture.
      Graphical abstract image

      PubDate: 2017-02-06T16:30:32Z
  • An investigation on the dynamics of domain switching of
           Bi0.5Na0.5TiO3-based ferroelectric ceramics
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Zhipeng Gao, Hang Zhang, Yi Liu, Lingfeng Wu, Jia Yang, Tao Zhang, Haiyan Wang, Xuefeng Chen, Genshui Wang, Hongliang He
      The dynamics of domain switching of Bi0.5Na0.5TiO3-based ferroelectric ceramic was investigated. With the electric field increasing, the domain switch experienced three sections of no domain switch region, creep region and flow region. In the creep region, the domain switch is dominated by the thermally activated domain wall movement. In flow region, the domain wall experience the viscous flow motion. For the BNT-BA-Zn ceramic, the activation energy of creep domain switch is much higher than it in flow region. With temperature increasing, the sensitivity of domain wall motion to the frequency is decreasing. This result demonstrated the domain switch of different ferroelectric materials could be quantitatively analyzed and compared based on the simple polarization - current - electric field data.

      PubDate: 2017-02-06T16:30:32Z
  • Solvothermal synthesis of high-performance Ni-Co layered double hydroxide
           nanofoam electrode for electrochemical energy storage
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Rajkumar Patel, Akbar I. Inamdar, Bo Hou, SeungNam Cha, Abu Talha Ansari, Jayavant L. Gunjakar, Hyunsik Im, Hyungsang Kim
      A nanofoam nickel cobalt layered double hydroxide (NiCo(OH)2) electrode film is fabricated on a stainless-steel substrate with the use of a simple one-step solvothermal process. The nanofoam NiCo(OH)2 electrode exhibits a high specific capacitance of 2710.2 F/g at a current density of 9.1 A/g, and a good capacity retention of ∼70% after 2000 charge-discharge cycles at a high current density of 31.8 A/g. An energy density of 60.23 Wh/kg is obtained at a power density of 1.8 kW/kg. The excellent electrochemical energy storage performance of the NiCo(OH)2 electrode is due to the synergetic effect of a significantly improved ionic diffusion and an effective charge transfer, which is linked to a well-dispersed interconnected nanofoam morphology and binder-free direct contact with the current collector.
      Graphical abstract image

      PubDate: 2017-02-06T16:30:32Z
  • Exponential decrease of scission length and low tensile strength of
           bamboo-shaped multi-walled carbon nanotubes under ultrasonication
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Jae-Won Jang, Cheol Eui Lee, Cheol Jin Lee
      We report here scission of bamboo-shaped multi-walled carbon nanotubes (BS-MWCNTs) under ultrasonication. As the applied sonication energy increases, mean length of BS-MWCNTs decreases. When sonication energy increases over 500 J/mL, the length of BS-MWCNTs no longer decreases; the limited scission length (L 0 ) is about 1.7 μm for BS-MWCNTs with diameter between 50 and 100 nm. From the L 0 of BS-MWCNTs, their tensile strength (σ∗) is calculated and found to be smaller than that of multi-walled carbon nanotubes (MWCNTs). In addition, exponential decrease of the length of BS-MWCNTs with increasing sonication energy is observed, which is distinguished from typical power law dependence of sonication-induced scission of MWCNTs. These exclusive characteristics in the scission of BS-MWCNTs under ultrasonication are regarded to result from weak binding at discontinuous graphene sheets obtained from forming compartment structures of BS-MWCNTs during growth.

      PubDate: 2017-02-06T16:30:32Z
  • Spin-polarization-induced anisotropic magnetoresistance in a
           two-dimensional Rashba system
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Won Young Choi, Hyung-jun Kim, Joonyeon Chang, Gyungchoon Go, Kyung-Jin Lee, Hyun Cheol Koo
      In an asymmetric two-dimensional electron gas system, the Rashba effective field arises due to the intrinsic electric field. Even without ferromagnetism, the Rashba spin splitting acts as a source of spin polarization and affects the transport property of the two-dimensional electron channel. In this Rashba channel, the magnetoresistance is determined by the vector alignment between the applied field and the bias current. In addition, the channel resistance for the parallel alignment between the applied field and the Rashba field is much smaller than that for the antiparallel alignment between them, which surprisingly agrees with the spin polarization induced by the Edelstein effect. This anisotropic magnetoresistance also allows us to estimate the spin polarization in a two-dimensional quantum well channel.

      PubDate: 2017-02-06T16:30:32Z
  • Continuously deposited anti-reflection double layer of silicon nitride and
           silicon oxynitride for selective emitter solar cells by PECVD
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Sungeun Park, Hyomin Park, Dongseop Kim, Junggyu Nam, JungYup Yang, Dongho Lee, Byoung Koun Min, Kyung Nam Kim, Se Jin Park, Seongtak Kim, Dongchul Suh, Donghwan Kim, Hae-Seok Lee, Yoonmook Kang
      Silicon oxynitride (SiON) could be used in combination with silicon nitride (SiN) to form a multilayer anti-reflection coating on the front side of selective emitter solar cells. In this study, these double anti-reflection layers were fabricated by a continuous deposition technique using the plasma enhanced chemical vapor deposition method. We attempted to determine whether this method is fast and cost effective and can achieve higher efficiency for solar cell manufacture. The results show that the short circuit current density for the double layer anti-reflection coating on selective emitter solar cells was higher by 0.5 mA/cm2 compared to the single layer coating owing to the improved optical reflectance. The incorporation of a SiN/SiON stack into the anti-reflection layer of the CZ selective emitter solar cells yields an energy conversion efficiency of 19.4%, which is higher than the efficiency (19.18%) for the reference solar cells with single layer SiN anti-reflection coating.

      PubDate: 2017-02-06T16:30:32Z
  • Annealing effect on the magnetic properties of cobalt-based amorphous
    • Abstract: Publication date: Available online 4 February 2017
      Source:Current Applied Physics
      Author(s): Sumin Kim, Yong Jin Kim, Young Keun Kim, Haein Choi-Yim
      The annealing effects on the magnetic properties of the Co72B19.2Si4.8Cr4 and Co64.8Fe7.2B19.2Si4.8Cr4 alloy systems are reported. Ribbon samples with 2 mm width and 20–30 μm thickness for both compositions were synthesized by melt spinning. The as-spun samples were subjected to annealing at various temperatures below their glass transition temperatures for 15 min in a vacuum. The annealed systems tended to have improved soft magnetic characteristics, including higher saturation magnetization and lower coercivity values, while maintaining their amorphous phase. A high saturation magnetization of 87.8 emu g−1 and low coercivity of 0.084 Oe were obtained for Co64.8Fe7.2B19.2Si4.8Cr4 after annealing at 400 °C, which is a significant improvement in comparison to the magnetic properties of the as-spun ribbons.

      PubDate: 2017-02-06T16:30:32Z
  • Effect of device structure on the resistive switching characteristics of
           organic polymers fabricated through all printed technology
    • Abstract: Publication date: Available online 2 February 2017
      Source:Current Applied Physics
      Author(s): Muhammad Muqeet Rehman, Bong-Su Yang, Young-Jin Yang, Khasan S. Karimov, Kyung Hyun Choi
      Developments in organic bi-stable non-volatile memory devices have shown that organic materials are essential for the next generation of electrical memory unit owing to their low cost, high flexibility and large scalability. This study depicts an important aspect of organic memory devices by observing the effect of changing device structure on its switching characteristics. Memory devices with a bilayer and bulk-heterojunction structure were fabricated through an all printed technology by utilizing two organic polymers such as MEH: PPV and PMMA. Silver (Ag) was selected as the top and bottom electrode due to its high conductivity and easy processing. Though identical polymers were used in both device structures, but interestingly change in structure caused change in properties. It was observed that bilayer structure had much higher switching ratio and stability against various biasing cycles as compared to its bulk-heterojunction counterpart. Superior switching characteristics of bilayer structure were due to the presence of a well-defined interface between both polymers. Bulk-heterojunction device suffers the drawback of phase separation in a single organic layer between the two polymers.

      PubDate: 2017-02-06T16:30:32Z
  • Improved efficiency of dye-sensitized solar cell based on randomly ordered
           pore structure fabricated by dry deposition method
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Hyungsub Kim, Yomin Choi, Yunchan Park, Rajendra C. Pawar, Yong-Ho Choa, Caroline Sunyong Lee
      Porous TiO2 films were deposited onto FTO (fluorine doped tin oxide) substrate through dry deposition method, and polystyrene (PS) beads used as a sacrificial material. In addition, pore size was controlled by introducing 50-nm- and 300-nm-sized PS beads. Moreover, the improved porous film was obtained by varying weight ratios of TiO2 and PS powders to enhance DSSCs (dye-sensitized solar cell) efficiency. The DSSC with improved porous structure has shown efficiency of 6.8% with weight ratio (71.5%), which higher than that of only TiO2 layer (6.08%) and other compositions. The IPCE analysis showed the maximum absorbance over the wavelength range of 550–800 nm resulted in higher efficiency. EIS results indicated that the electron generation and transfer properties of porous films were better than that of the TiO2 layer only. From photovoltage decay measurement, the carrier lifetime was found to be longer in the porous structure than that of TiO2 layer only. Then, we proposed formation mechanism of porous films and their relation for effective scattering/absorbance of light. Moreover, the porous structure also enhances the specific surface area for higher amount of dye loading. Therefore, deposition of porous films could improve the efficiency of DSSCs using facile process.

      PubDate: 2017-01-31T11:31:13Z
  • A solution-processable inorganic hole injection layer that improves the
           performance of quantum-dot light-emitting diodes
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Sang Moo Lee, Dongguen Shin, Nam-Kwang Cho, Yeonjin Yi, Seong Jun Kang
      Solution-processable vanadium oxide (V2O5) was used as an inorganic hole injection layer (HIL) to improve the performance and stability of quantum-dot light-emitting diodes (QLEDs). Non-acidic and non-hygroscopic V2O5 solution was synthesized and spin-coated onto indium-tin-oxide (ITO)/glass substrate to serve as an HIL for QLEDs. QLEDs with a V2O5 HIL showed efficient hole injection and had improved luminous efficiency and life-time. Maximum luminance and luminous efficiency of QLEDs fabricated under ambient conditions were 12,603 cd/m2 and 2.96 Cd/A, respectively. Photoelectron spectroscopy measurements were conducted to construct an energy level diagram of the QLEDs, and we found that the gap states of V2O5 enabled efficient hole-injection from ITO into the devices through the V2O5 HIL, resulting in enhanced luminance. These results suggest that solution-processable V2O5 is a feasible alternative to organic HILs for high-performance QLEDs.
      Graphical abstract image

      PubDate: 2017-01-31T11:31:13Z
  • An improved genetic algorithm for crystal structure prediction
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): S.Y. Chen, F. Zheng, S.Q. Wu, Z.Z. Zhu
      We present an improved genetic algorithm (GA) for crystal structural prediction based on empirical potentials with a higher convergence rate. Some of the existed methods for crystal structure prediction via GA are much likely to suffer from stagnation during evolution, with a consequent loss of productivity and search depth. Some approaches, which include penalizing similar or identical structures in each generation to keep a rich diversity of structure in the population, and adjusting structures according to the possible space groups to skip the noise on the energy surface, are introduced herein to improve the GAs performance. Furthermore, the application of coevolution strategy between atomic positions and unit cell sizes and shapes via the local minimizer greatly reduces the computational cost. This has displayed an improvement in the quality of results found for the theoretical prediction of simple model crystal structures. The performance of the method is illustrated by successful identifications of known carbon and silicon carbide systems, but also gives some new promising structures (e.g., 2D structures). The high success rate of prediction demonstrates the dependability of this methodology and indicates the great potential of our method as a useful technique on crystal structure prediction.

      PubDate: 2017-01-31T11:31:13Z
  • Time-resolved photoluminescence of Cu(In,Ga)(Se,S)2 thin films and
           temperature dependent current density-voltage characteristics of their
           solar cells on surface treatment effect
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Jakapan Chantana, Takuya Kato, Hiroki Sugimoto, Takashi Minemoto
      Influences of the surface treatments of Cu(In,Ga)(Se,S)2 (CIGSSe) thin films, which are KCN, HCl, or thiuorea treatments, were investigated by time-resolved photoluminescence (TRPL) and temperature dependent current density-voltage (J-V) characteristics of their solar cells. It is demonstrated that the KCN treatment optimized under 1 wt% leads to the significant increase in conversion efficiency (η) up to 19.21%. On the other hand, the η of the CIGSSe solar cells is in ranges of 13.70–15.51% and 9.86–10.70% with the HCl treatments (0.3–0.7 mol/L), and thiuorea treatments (0.5–1.5 mol/L), respectively, which are lower than 16.66% that of the reference solar cell without the surface treatment. According to TRPL measurements, the quality of near-surface CIGSSe is improved with the KCN treatment (1 wt%) owing to enhanced TRPL lifetimes, whereas that is deteriorated with the HCl and thiuorea treatments due to decreased TRPL lifetimes. In addition, according to the temperature-dependent J-V measurement, the interface recombination of the CIGSSe solar cell is decreased with the KCN treatment, while that of the CIGSSe solar cells is increased with the HCl and thiuorea treatments. Ultimately, 19.21%-efficient CIGSSe solar cell with the KCN treatment (1 wt%) at room temperature with the increased V OC of 0.692 V was obtained, which is around 15.3% relatively higher η than that of the solar cell without the surface treatment.

      PubDate: 2017-01-31T11:31:13Z
  • Logarithmic temperature dependence of resistivity in CVD graphene
    • Abstract: Publication date: April 2017
      Source:Current Applied Physics, Volume 17, Issue 4
      Author(s): Kanji Takehana, Yasutaka Imanaka, Eiichiro Watanabe, Hirotaka Oosato, Daiju Tsuya, Yongmin Kim, Ki-Seok An
      Logarithmical increase of the longitudinal resistivity ( ρ x x ) between 10 K and 80 K and its saturation at low temperature were observed in the graphene synthesized by the chemical vapor deposition (CVD) with various applied gate voltage. In the two-dimensional system, it is considerably difficult to identify the origin of the logarithmic temperature (Log-T) increase of the resistivity, because there are three corrections to exhibit the Log-T behavior: the weak localization, the electron-electron interaction (EEI) in the disordered system and the Kondo effect. In order to distinguish the origin of the Log-T behavior, we contrived a new method utilizing the magnetotransport property in tilted magnetic fields. As a result, we have assigned the Log-T behavior in the CVD graphene to the correction of the EEI.

      PubDate: 2017-01-31T11:31:13Z
  • Mechanical induced electrical failure of shock compressed PZT95/5
           ferroelectric ceramics
    • Abstract: Publication date: Available online 14 January 2017
      Source:Current Applied Physics
      Author(s): Hengchang Nie, Jia Yang, Xuefeng Chen, Fuping Zhang, Yin Yu, Genshui Wang, Yusheng Liu, Hongliang He, Xianlin Dong
      A comparative experimental study of shock compressed Pb0.99(Zr0.95Ti0.05)0.98Nb0.02O3 (hereafter referred to as PZT95/5) ferroelectric ceramics within different insulation materials were performed in this study. It was found that the insulating materials play a significant role in the electrical failure behavior of PZT95/5 ferroelectric ceramic. The electrical breakdown behavior of PZT95/5 ferroelectric ceramics within epoxy resin was observed to aggravate at low temperature −55 °C. Porous PZT95/5 ferroelectric ceramic was found to exhibit lower failure probability than its dense counterpart. Electrical failure of PZT95/5 ferroelectric ceramics under shock wave was found to be an extrinsic behavior and a tentative explanation was proposed based on the mechanical compressive stress-induced cracks initiation by epoxy resin.

      PubDate: 2017-01-18T11:02:14Z
  • Effect of low Cobalt doping on morphology and properties of calcium
           ferrite and its application as cathode in Solid oxide Fuel cell
    • Abstract: Publication date: Available online 13 January 2017
      Source:Current Applied Physics
      Author(s): Suchita Dhankhar, Pankaj Tiwari, K. Baskar, Suddhasatwa Basu, Shubra Singh
      Cobaltite perovskites, such as polycrystalline complex brownmillerite oxide Ca2Fe2−xCoxO5, possess high catalytic activity with potential application as cathode materials for Solid oxide fuel cells. However, high Co concentration can lead to high thermal expansion coefficient (∼13 × 10−6 K−1), which makes them incompatible with widely used Zirconia electrolytes. In the present work we employ low Co concentration and elucidate the effect of morphology on the physical properties of wet chemical synthesized Ca2Fe2−xCoxO5 (x = 0, 0.01, 0.03). Oxygen stoichiometry was determined from iodometry titration at room temperature. Co incorporation in the lattice, as low as 1 mol%, reveals a change in morphology and grain size. We also evaluate the role of Ca2Fe2−xCoxO5 samples as cathode material in a bilayer (Cathode/Electrolyte) based on Ce0.9Sm0.1O2 (Samarium doped Ceria) solid electrolyte. Alternating Current (A.C) impedance spectroscopy showed variation in ionic conductivity with respect to temperature for Ca2Fe2−xCoxO5 (x = 0, 0.01, 0.03) in a temperature range from 400 °C to 800 °C. Activation energy with respect to Co-doping and temperature is reported. The complex impedance plane plots show a relaxed mechanism due to grain size effect. Scaling behavior of imaginary part of impedance indicates that relaxation follows similar mechanism at various temperatures.
      Graphical abstract image

      PubDate: 2017-01-18T11:02:14Z
  • Interfacial engineering for highly efficient organic solar cells
    • Abstract: Publication date: March 2017
      Source:Current Applied Physics, Volume 17, Issue 3
      Author(s): Bright Walker, Hyosung Choi, Jin Young Kim
      Interfacial engineering using metal oxides, organic surface modifiers and other materials can effectively enhance the performance of conventional and inverted organic solar cells by reducing energy barriers for charge transport, while improving compatibility between organic active layer and inorganic metal oxides or transparent conducting electrodes. This short review introduces several important classes of interfacial materials which have been widely successful in improving the efficiency of organic solar cells, and covers some of the recent advances in this field.

      PubDate: 2017-01-10T12:51:09Z
  • Growth mechanism of Co thin films formed by plasma-enhanced atomic layer
           deposition using NH3 as plasma reactant
    • Abstract: Publication date: March 2017
      Source:Current Applied Physics, Volume 17, Issue 3
      Author(s): Il-Kwon Oh, Hyungjun Kim, Han-Bo-Ram Lee
      We investigated reaction mechanisms for the formation of Co thin films by plasma-enhanced atomic layer deposition (PE-ALD) using NH3 plasma as a counter-reactant. To investigate surface reactions during the PE-ALD Co, the process was divided into two half-reactions and these reactions were monitored using ex situ X-ray photoelectron spectroscopy (XPS) and an in situ residual gas analyzer (RGA). The cobaltocene (bis(cyclopentadienyl)-cobalt(II), CoCp2) precursor reacts with the N-terminated surface formed by NH3 plasma exposure, resulting in the formation of Co–Co bonds and the release of the Cp ligand and an N-containing byproduct. The NH3 plasma species adsorb to Co–Cp sites and promote dissociation of Cp. Therefore, N atoms on the surface are a key medium for the deposition of Co thin films during sequential adsorption and desorption reactions between CoCp2 and the surface. This result provides an insight into complicated chemical reactions involving PE-ALD and can be extended to other PE-ALD processes.

      PubDate: 2016-12-30T05:28:14Z
  • On the correlation of growth, structural and electrical properties of
           epitaxial Ge grown on Si by solid source molecular beam epitaxy
    • Abstract: Publication date: March 2017
      Source:Current Applied Physics, Volume 17, Issue 3
      Author(s): Sudipta Das, Krista R. Khiangte, Rajveer S. Fandan, Jaswant S. Rathore, Ravindra S. Pokharia, Suddhasatta Mahapatra, Apurba Laha
      We report growth, structural, and electrical properties of epitaxial Ge layers on Si (001) wafers for next generation complementary metal oxide semiconductor devices. The epi-Ge layers were grown by solid source molecular beam epitaxy (MBE) at substrate temperatures (TG) varying from 200 °C to 500 °C. A two-step growth process, where an initial layer of thickness ∼30 nm is grown at a substrate temperature of 250 °C (except those grown below/at 250 °C), and the remaining layer is grown at a higher temperature, was found to be an efficient approach to improve the crystal quality of the Ge layers. The epi-Ge on Si exhibits bulk hole-mobility as high as 736 cm2/V-s at room temperature. Ti/Ge/Ti metal-semiconductor-metal (MSM) back-to-back Schottky diodes, fabricated on these epitaxial Ge layers, show excellent electrical properties. Further, metal oxide semiconductor (MOS) capacitors fabricated with HfO2 as the gate oxide exhibit low leakage current density of 4.7 × 10−2 A/cm2 (at Vg−VFB = 1 V) and mid-gap interface trap density of 5.0 × 1012cm−2eV−1.

      PubDate: 2016-12-30T05:28:14Z
  • Highly stretchable polymer composite microtube chemical sensors produced
           by the meniscus-guided approach
    • Abstract: Publication date: March 2017
      Source:Current Applied Physics, Volume 17, Issue 3
      Author(s): Kyu Hwang Won, Byung Mook Weon, Jung Ho Je
      Highly stretchable polymer composite microtubes of poly(methyl methacrylate)/polypyrrole (PMMA/PPy) were produced as a microarch shape by a meniscus-guided approach using colloidal solutions of the composite polymers. The polymer composite (PMMA/PPy) microarches show high stretchability up to 80% maintaining the electrical properties. Moreover, the microarches endure repeated stretching over 10 4 ( 9 × 10 2 ) cycles at 20% (80%) stretching without degradation of the electrical properties. The stretchable PMMA/PPy microtube arches are demonstrated as gas sensors with persistent sensitivities and response (recovery) times up to 80% stretching for various NH3 concentrations. These robust properties of the stretchable PMMA/PPy microtube arch sensors can be suitable for portable sensing devices operating under extreme stretching conductions to be used in research laboratories and chemical processing industries for chemical leak detection and environmental monitoring.

      PubDate: 2016-12-30T05:28:14Z
  • Surfactant-treated graphene oxide in organic solvents and its application
           in photovoltaic cells
    • Abstract: Publication date: March 2017
      Source:Current Applied Physics, Volume 17, Issue 3
      Author(s): Yishan Wang, Shengyi Yang, Haowei Wang, Li Zhang, Haijuan Cheng, Bo He, Weile Li, Bingsuo Zou
      In this paper, a simple and non-poisonous “surfactant treatment” method to prepare graphene oxide (GO) in organic solvents with good dispersibility was presented. As the surfactant molecules, didodecyldimethyla-mmonium bromide (DDAB) was attached onto the GO sheets via ionic interactions by mild sonication, the obtained GO:DDAB nanocomposites were then blended into copolymer Poly(3-hexylthiophene-2,5-diyl) (P3HT) [6,6]:-Phenyl C61 butyric acid methyl ester (PC61BM) as the active layer to fabricate bulk-heterojunction (BHJ) organic solar cells ITO/PEDOT:PSS/P3HT:PC61BM:(GO:DDAB)/Ca/Al. The concentration of GO:DDAB in the active layer, a maximum power conversion efficiency (PCE) of 3.67% was obtained by blending 0.5 mg/mL GO:DDAB in the active layer, showing an efficiency increment of 13.35% as compared with that of the control device without doping GO:DDAB. The optimized OPVs with PTB7:PC71BM by adding GO:DDAB shows the PCE of 7.96%. Therefore, it paves a way to get high efficiency organic photovoltaic cells by directly blending surfactant-treated graphene oxide in organic solvent.

      PubDate: 2016-12-30T05:28:14Z
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