The Experts below are selected from a list of 16386 Experts worldwide ranked by ideXlab platform
Jong Hyeok Park - One of the best experts on this subject based on the ideXlab platform.
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unassisted photoelectrochemical water splitting exceeding 7 solar to hydrogen conversion efficiency using photon recycling
Nature Communications, 2016Co-Authors: Xinjian Shi, Hokyeong Jeong, Kan Zhang, Jeong Kwon, In Taek Choi, Il Yong Choi, Hwan Kyu Kim, Jong Kyu Kim, Jong Hyeok ParkAbstract:Various tandem cell configurations have been reported for highly efficient and spontaneous hydrogen production from photoelectrochemical solar water splitting. However, there is a contradiction between two main requirements of a front photoelectrode in a tandem cell configuration, namely, high transparency and high photocurrent density. Here we demonstrate a simple yet highly effective method to overcome this contradiction by incorporating a hybrid conductive distributed Bragg reflector on the back side of the transparent Conducting Substrate for the front photoelectrochemical electrode, which functions as both an optical filter and a conductive counter-electrode of the rear dye-sensitized solar cell. The hybrid conductive distributed Bragg reflectors were designed to be transparent to the long-wavelength part of the incident solar spectrum (λ>500 nm) for the rear solar cell, while reflecting the short-wavelength photons (λ<500 nm) which can then be absorbed by the front photoelectrochemical electrode for enhanced photocurrent generation.
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controlled synthesis of vertically aligned hematite on Conducting Substrate for photoelectrochemical cells nanorods versus nanotubes
ACS Applied Materials & Interfaces, 2011Co-Authors: Aiming Mao, Kahee Shin, Jung Kyu Kim, Dong Hwan Wang, Gui Young Han, Jong Hyeok ParkAbstract:This paper describes two different processes to synthesize vertically aligned hematite nanorod and nanotube arrays, respectively, on a conductive Substrate by the electrochemical deposition method with the help of an anodized aluminum oxide nanotemplate. The two types of nanostructured hematite were used as the photoanode for photoelectrochemical cells. The hematite nanotubes exhibited much higher photoelectrochemical activity than the hematite nanorods, including an improved photocurrent density, more negative onset potential, better photon harvesting, and better charge carrier transfer ability. The observed behavior may offer new information to enhance the photocatalytic ability of hematite, which is considered to be one of the best photoanode materials in the research field of photoelectrochemical cells.
Kamila Zarebska - One of the best experts on this subject based on the ideXlab platform.
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electrodeposition of zno nanorod arrays on transparent Conducting Substrates a review
Electrochimica Acta, 2014Co-Authors: Magdalena Skompska, Kamila ZarebskaAbstract:Abstract ZnO nanorods (NRs) are promising components in a wide range of nanoscale devices for future applications in photocatalysis, solar cells, optical devices and biochemical sensing. The nanorods in the form of arrays vertically oriented to the Substrate may be obtained by electrochemical deposition but morphology of the film is very sensitive to the synthesis conditions. This article provides a comprehensive review on various electrosynthesis procedures developed to obtain the nanorods of desired structure, diameter, density on the Substrate. We discuss the growth mechanisms and influence of different parameters such as the type and concentration of Zn 2+ and OH − precursors, the value of applied potential or current density on the morphology of obtained ZnO films and the role of various structural modifiers on the shape of ZnO nanostructures. We present a brief analysis of the influence of electrosynthesis conditions and postannealing of the samples on optical and electrical properties of ZnO nanowires deposited on the Conducting Substrate. A short summary of the practical applications of ZnO nanorods is also provided.
Magdalena Skompska - One of the best experts on this subject based on the ideXlab platform.
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electrodeposition of zno nanorod arrays on transparent Conducting Substrates a review
Electrochimica Acta, 2014Co-Authors: Magdalena Skompska, Kamila ZarebskaAbstract:Abstract ZnO nanorods (NRs) are promising components in a wide range of nanoscale devices for future applications in photocatalysis, solar cells, optical devices and biochemical sensing. The nanorods in the form of arrays vertically oriented to the Substrate may be obtained by electrochemical deposition but morphology of the film is very sensitive to the synthesis conditions. This article provides a comprehensive review on various electrosynthesis procedures developed to obtain the nanorods of desired structure, diameter, density on the Substrate. We discuss the growth mechanisms and influence of different parameters such as the type and concentration of Zn 2+ and OH − precursors, the value of applied potential or current density on the morphology of obtained ZnO films and the role of various structural modifiers on the shape of ZnO nanostructures. We present a brief analysis of the influence of electrosynthesis conditions and postannealing of the samples on optical and electrical properties of ZnO nanowires deposited on the Conducting Substrate. A short summary of the practical applications of ZnO nanorods is also provided.
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defect minimization and morphology optimization in tio2 nanotube thin films grown on transparent Conducting Substrate for dye synthesized solar cell application
Thin Solid Films, 2012Co-Authors: Oleksandr Kuzmych, Kazuteru Nonomura, Erik M J Johansson, Tomas Nyberg, Anders Hagfeldt, Magdalena SkompskaAbstract:TiO2 nanotube (TNT) arrays have proven to be a perspective material for dye-or semiconductor sensitized solar cells. Although their preparation by anodic oxidation method is well elaborated for Ti foil Substrate, the synthesis of high quality, homogeneous TNT arrays on a transparent conductive oxide (TCO) is still associated with some experimental challenges. In this paper we present a way of preparation of defect-free, homogenous TNT film on a TCO Substrate by a combination of high temperature Ti sputtering and controlled "interrupted" anodization in viscous electrolyte. High temperature of the Substrate during Ti sputter coating was found crucial for good adhesion between the Ti thin film and TCO, which seems to be the most important condition for synthesis of TNTs from a Ti thin film. The reason of poor adhesion of the Ti layer sputtered at room temperature is discussed in terms of internal stress forces. An Ar-ion sputtering was proposed as a method for removal of the non-organized top porous layer to reveal a well organized tubular geometry of TNTs and control their final lengths. Such control of morphology of the top layer is important for preparation of solid state solar cells.
D. Fournier - One of the best experts on this subject based on the ideXlab platform.
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Thermal insulating layer on a Conducting Substrate. Analysis of thermoreflectance experiments
Journal of Applied Physics, 2012Co-Authors: Christian Frétigny, Jean-yves Duquesne, D. FournierAbstract:Thermoreflectance experiments are sensitive to the thermal properties of thin layers deposited on Substrates (conductivity and diffusivity). However, retrieving these properties from experimental data remains a difficult issue. The case of a Conducting layer deposited on an insulating Substrate was studied previously. We present here a mathematical and experimental analysis of the thermoreflectance response in the opposite case: an insulating layer on a Conducting Substrate. We show theoretically that conductivity and diffusivity can be determined independently thanks to a comparison with the Substrate. The method is applied to experiments performed on a silicon Substrate covered with a thin layer deposited by sputtering a titanium target.
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Thermal insulating layer on a Conducting Substrate. Analysis of thermoreflectance experiments
Journal of Applied Physics, 2012Co-Authors: Christian Frétigny, Jean-yves Duquesne, D. FournierAbstract:Thermoreflectance experiments are sensitive to the thermal properties of thin layers deposited on Substrates (conductivity and diffusivity). However, retrieving these properties from experimental data remains a difficult issue. The case of a Conducting layer deposited on an insulating Substrate was studied previously. We present here a mathematical and experimental analysis of the thermoreflectance response in the opposite case: an insulating layer on a Conducting Substrate. We show theoretically that conductivity and diffusivity can be determined independently thanks to a comparison with the Substrate. The method is applied to experiments performed on a silicon Substrate covered with a thin layer deposited by sputtering a titanium target. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3702823]
Gary Hodes - One of the best experts on this subject based on the ideXlab platform.
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Uniform Coating of Light-Absorbing Semiconductors by Chemical Bath Deposition on Sulfide-Treated ZnO Nanorods
Journal of Physical Chemistry C, 2010Co-Authors: Eran Edri, Elena Rabinovich, Olivia Niitsoo, Hagai Cohen, Tatyana Bendikov, Gary HodesAbstract:ZnO nanorod films are increasingly used as an alternative to nanoporous TiO2 as the electron conductor in semiconductor-sensitized nanoporous solar cells (SSSCs). Semiconductor light absorbers deposited onto ZnO by chemical bath deposition (CBD) tend to form poorly covering deposits of isolated clusters. We show how a short solution pretreatment of the ZnO nanorod films with a sulfide solution, which forms a thin ZnS film at the ZnO surface, results in a very large improvement of the coverage and uniformity of the CBD semiconductor coatings. These composite films give large improvements in solar cell efficiency. Several factors can be responsible for this improvement: better coverage of the ZnO nanorods, less shorting between hole conductor and Conducting Substrate, and the formation of a ZnS buffer layer.