The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Hideo Hosono - One of the best experts on this subject based on the ideXlab platform.
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origins of hole doping and relevant optoelectronic properties of wide gap p Type Semiconductor lacuose
Journal of the American Chemical Society, 2010Co-Authors: Hidenori Hiramatsu, Toshio Kamiya, Tetsuya Tohei, Eiji Ikenaga, Teruyasu Mizoguchi, Yuichi Ikuhara, Keisuke Kobayashi, Hideo HosonoAbstract:LaCuOSe is a wide band gap (∼2.8 eV) Semiconductor with unique optoelectronic properties, including room-temperature stable excitons, high hole mobility ∼8 cm2/(Vs), and the capability of high-density hole doping (up to 1.7 × 1021 cm−3 using Mg). Moreover, its carrier transport and doping behaviors exhibit nonconventional results, e.g., the hole concentration increases with decreasing temperature and the high hole doping does not correlate with other properties such as optical absorption. Herein, secondary ion mass spectroscopy and photoemission spectroscopy reveal that aliovalent ion substitution of Mg at the La site is not the main source of hole doping and the Fermi level does not shift even in heavily doped LaCuOSe:Mg. As the hole concentration increases, the subgap optical absorption becomes more intense, but the increase in intensity does not correlate quantitatively. Transmission electron microscopy indicates that planar defects composed of Cu and Se deficiencies are easily created in LaCuOSe. Thes...
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heavy hole doping of epitaxial thin films of a wide gap p Type Semiconductor lacuose and analysis of the effective mass
Applied Physics Letters, 2007Co-Authors: Hidenori Hiramatsu, Kazushige Ueda, Hiromichi Ohta, Masahiro Hirano, Maiko Kikuchi, Hiroshi Yanagi, Toshio Kamiya, Hideo HosonoAbstract:The high density hole doping (1.7×1021cm−3) for a wide gap (Eg=∼2.8eV) p-Type Semiconductor was achieved on 40nm thick Mg-doped LaCuOSe epitaxial films. These films exhibited distinct free carrier absorption, and the effective mass and momentum relaxation time were analyzed. Its small hole mobility [∼3.5cm2∕(Vs)] compared to the electron mobilities of wide gap n-Type Semiconductors is attributed to a heavy effective mass of 1.6±0.2me. Regardless of the heavy hole doping, a band filling effect was not observed. These results are discussed with a rigid band model and an acceptor band model.
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Heteroepitaxial growth of a wide-gap p-Type Semiconductor, LaCuOS
Applied Physics Letters, 2002Co-Authors: Hidenori Hiramatsu, Kazushige Ueda, Hiromichi Ohta, Masahiro Orita, Masahiro Hirano, Hideo HosonoAbstract:High-quality epitaxial films of LaCuOS, a wide-gap p-Type Semiconductor, are grown on yittria-stabilized-zirconia (001) or MgO (001) single-crystal substrates by a unique method. Postannealing of a bilayer film composed of an extremely thin metallic copper layer and an amorphous LaCuOS layer at 1000 °C results in an epitaxially grown LaCuOS thin film. This thin copper layer with high orientation, which likely acts as an epitaxial initiator, is essential for epitaxial growth. The resulting epitaxial films exhibit relatively intense ultraviolet emission associated with excitons at room temperature, confirming the high crystal quality of the films.
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transparent p Type Semiconductor lacuos layered oxysulfide
Applied Physics Letters, 2000Co-Authors: Kazushige Ueda, Shinichiro Inoue, Sakyo Hirose, Hiroshi Kawazoe, Hideo HosonoAbstract:La1−xSrxCuOS (x=0, 0.05) thin films prepared by radio-frequency sputtering were found to have high optical transmission (⩾70%) at the visible and near-infrared wavelengths and an energy gap of about 3.1 eV. The dc electrical conductivities of x=0 and 0.05 thin films at room temperature were 1.2×10−2 and 2.6×10−1 S cm−1, respectively. The Seebeck coefficients of these samples were positive, indicating that p-Type electrical conduction is dominant in these materials. A sharp photoluminescence peak, probably originating from an interband transition, was observed at the optical absorption edge. The present study demonstrates that LaCuOS is a promising transparent p-Type Semiconductor for optoelectronic applications. Moreover, our material design, based on chemical modulation of the valence band, was successfully extended to oxysulfide systems.
Fabrice Odobel - One of the best experts on this subject based on the ideXlab platform.
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Improved efficiency of PbS quantum dot sensitized NiO photocathodes with naphthalene diimide electron acceptor bound to the surface of the nanocrystals
Solar Energy Materials and Solar Cells, 2018Co-Authors: Mahfoudh Raissi, Muhammad T. Sajjad, Yoann Farre, Thomas J. Roland, Arvydas Ruseckas, Ifor D. W. Samuel, Fabrice OdobelAbstract:Hybrid materials combining a wide bandgap metal oxide Semiconductor, metal chalcogenide nanocrystals and molecular systems represent very attractive materials for fabricating devices with new function or improved photoelectrochemical performance. This study deals with sensitization of NiO, which is a p-Type Semiconductor, by quantum dots (QDs) of PbS with an average diameter of 3 nm. The PbS QDs were attached to the mono crystalline film of NiO by mercaptopropionic acid linker and were subsequently capped with methyl-pyridine naphthalene diimide (NDI) units to prepare quantum dot sensitized solar cells (p-QDSSCs) on NiO electrodes. Time-resolved photoluminescence measurements of the PbS emission were used to determine the rate constants for charge transfer from the PbS exciton to the NiO, cobalt based redox mediator and NDI. Notably, it was shown that NDI quenches the PbS exciton by electron transfer with a quite fast rate constant (6.9 x 10(7) s(-1)). The PbS QDs sensitized NiO films were finally used to fabricate solar cells with tris(4,4'-ditert-butyl-2,2'-bipyridine) cobalt(III/II) as redox mediator. It was observed that the presence of NDI on PbS improved the photovoltaic performance by 50% relative to that of cells without NDI, leading to a device with the following characteristics: Jsc = 5.75 mA/cm(2), Voc = 226 mV, ff = 34% and PCE = 0.44%. This study demonstrates that photogalvanic processes can be a productive pathway to better performing sensitized p-Type Semiconductor for p-QDSSC. In other words, photoinduced electron transfer from the QDs towards the electrolyte rather than initial photo induced charge injection into the p-Type Semiconductor can be a favorable operative mechanism in QD sensitized NiO films and might be exploited further for the construction of better performing solar cells or photocatalytic devices.
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The first dye-sensitized solar cell with p-Type LaOCuS nanoparticles as a photocathode
RSC Advances, 2015Co-Authors: Adele Renaud, Yann Pellegrin, Fabrice Odobel, Errol Blart, Laurent Cario, Mohammed Boujtita, Stephane JobicAbstract:Layered LaOCuS oxysulfide is a well-known wide band gap p-Type Semiconductor that has attracted strong interests for transparent electronics. We report here that nanoparticles of this material can also be used as a substitute for the widely used NiO compound to fabricate photocathodes for p-Type dye sensitized solar cells.
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Molecular Engineering of Efficient Dyes for p-Type Semiconductor Sensitization
High-Efficiency Solar Cells, 2013Co-Authors: Fabrice Odobel, Frédéric B. Anne, Yann Pellegrin, Denis JacqueminAbstract:Dye-sensitized solar cells (DSCs) based on p-Type Semiconductors such as nickel oxide have attracted considerable attention during the past 5 years. In this chapter, we focus on the progress related to improving p-DSC efficiency with the sensitizer. First, we summarize the specificities of p-DSC relative to conventional Grätzel cells, and then we establish the requirements for an efficient sensitizer. Second, we review all the results on published dyes and discuss the strategy for improvements. The molecular design principles of the dyes are also presented in order to pave the way and stimulate new directions.
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New Photovoltaic Devices Based on the Sensitization of p-Type Semiconductors: Challenges and Opportunities
Accounts of chemical research, 2010Co-Authors: Fabrice Odobel, Yann Pellegrin, Loïc Le Pleux, Errol BlartAbstract:Because solar energy is the most abundant renewable energy resource, the clear connection between human activity and global warming has strengthened the interest in photovoltaic science. Dye-sensitized solar cells (DSSCs) provide a promising low-cost technology for harnessing this energy source. Until recently, much of the research surrounding DSSCs had been focused on the sensitization of n-Type Semiconductors, such as titanium dioxide (Gratzel cells). In an n-Type dye-sensitized solar cell (n-DSSC), an electron is injected into the conduction band of an n-Type Semiconductor (n-SC) from the excited state of the sensitizer. Comparatively few studies have examined the sensitization of wide bandgap p-Type Semiconductors. In a p-Type DSSC (p-DSSC), the photoexcited sensitizer is reductively quenched by hole injection into the valence band of a p-Type Semiconductor (p-SC). The study of p-DSSCs is important both to understand the factors that control the rate of hole photoinjection and to aid the rational desi...
Hidenori Hiramatsu - One of the best experts on this subject based on the ideXlab platform.
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origins of hole doping and relevant optoelectronic properties of wide gap p Type Semiconductor lacuose
Journal of the American Chemical Society, 2010Co-Authors: Hidenori Hiramatsu, Toshio Kamiya, Tetsuya Tohei, Eiji Ikenaga, Teruyasu Mizoguchi, Yuichi Ikuhara, Keisuke Kobayashi, Hideo HosonoAbstract:LaCuOSe is a wide band gap (∼2.8 eV) Semiconductor with unique optoelectronic properties, including room-temperature stable excitons, high hole mobility ∼8 cm2/(Vs), and the capability of high-density hole doping (up to 1.7 × 1021 cm−3 using Mg). Moreover, its carrier transport and doping behaviors exhibit nonconventional results, e.g., the hole concentration increases with decreasing temperature and the high hole doping does not correlate with other properties such as optical absorption. Herein, secondary ion mass spectroscopy and photoemission spectroscopy reveal that aliovalent ion substitution of Mg at the La site is not the main source of hole doping and the Fermi level does not shift even in heavily doped LaCuOSe:Mg. As the hole concentration increases, the subgap optical absorption becomes more intense, but the increase in intensity does not correlate quantitatively. Transmission electron microscopy indicates that planar defects composed of Cu and Se deficiencies are easily created in LaCuOSe. Thes...
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heavy hole doping of epitaxial thin films of a wide gap p Type Semiconductor lacuose and analysis of the effective mass
Applied Physics Letters, 2007Co-Authors: Hidenori Hiramatsu, Kazushige Ueda, Hiromichi Ohta, Masahiro Hirano, Maiko Kikuchi, Hiroshi Yanagi, Toshio Kamiya, Hideo HosonoAbstract:The high density hole doping (1.7×1021cm−3) for a wide gap (Eg=∼2.8eV) p-Type Semiconductor was achieved on 40nm thick Mg-doped LaCuOSe epitaxial films. These films exhibited distinct free carrier absorption, and the effective mass and momentum relaxation time were analyzed. Its small hole mobility [∼3.5cm2∕(Vs)] compared to the electron mobilities of wide gap n-Type Semiconductors is attributed to a heavy effective mass of 1.6±0.2me. Regardless of the heavy hole doping, a band filling effect was not observed. These results are discussed with a rigid band model and an acceptor band model.
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Heteroepitaxial growth of a wide-gap p-Type Semiconductor, LaCuOS
Applied Physics Letters, 2002Co-Authors: Hidenori Hiramatsu, Kazushige Ueda, Hiromichi Ohta, Masahiro Orita, Masahiro Hirano, Hideo HosonoAbstract:High-quality epitaxial films of LaCuOS, a wide-gap p-Type Semiconductor, are grown on yittria-stabilized-zirconia (001) or MgO (001) single-crystal substrates by a unique method. Postannealing of a bilayer film composed of an extremely thin metallic copper layer and an amorphous LaCuOS layer at 1000 °C results in an epitaxially grown LaCuOS thin film. This thin copper layer with high orientation, which likely acts as an epitaxial initiator, is essential for epitaxial growth. The resulting epitaxial films exhibit relatively intense ultraviolet emission associated with excitons at room temperature, confirming the high crystal quality of the films.
Errol Blart - One of the best experts on this subject based on the ideXlab platform.
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The first dye-sensitized solar cell with p-Type LaOCuS nanoparticles as a photocathode
RSC Advances, 2015Co-Authors: Adele Renaud, Yann Pellegrin, Fabrice Odobel, Errol Blart, Laurent Cario, Mohammed Boujtita, Stephane JobicAbstract:Layered LaOCuS oxysulfide is a well-known wide band gap p-Type Semiconductor that has attracted strong interests for transparent electronics. We report here that nanoparticles of this material can also be used as a substitute for the widely used NiO compound to fabricate photocathodes for p-Type dye sensitized solar cells.
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New Photovoltaic Devices Based on the Sensitization of p-Type Semiconductors: Challenges and Opportunities
Accounts of chemical research, 2010Co-Authors: Fabrice Odobel, Yann Pellegrin, Loïc Le Pleux, Errol BlartAbstract:Because solar energy is the most abundant renewable energy resource, the clear connection between human activity and global warming has strengthened the interest in photovoltaic science. Dye-sensitized solar cells (DSSCs) provide a promising low-cost technology for harnessing this energy source. Until recently, much of the research surrounding DSSCs had been focused on the sensitization of n-Type Semiconductors, such as titanium dioxide (Gratzel cells). In an n-Type dye-sensitized solar cell (n-DSSC), an electron is injected into the conduction band of an n-Type Semiconductor (n-SC) from the excited state of the sensitizer. Comparatively few studies have examined the sensitization of wide bandgap p-Type Semiconductors. In a p-Type DSSC (p-DSSC), the photoexcited sensitizer is reductively quenched by hole injection into the valence band of a p-Type Semiconductor (p-SC). The study of p-DSSCs is important both to understand the factors that control the rate of hole photoinjection and to aid the rational desi...
Stephane Jobic - One of the best experts on this subject based on the ideXlab platform.
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The first dye-sensitized solar cell with p-Type LaOCuS nanoparticles as a photocathode
RSC Advances, 2015Co-Authors: Adele Renaud, Yann Pellegrin, Fabrice Odobel, Errol Blart, Laurent Cario, Mohammed Boujtita, Stephane JobicAbstract:Layered LaOCuS oxysulfide is a well-known wide band gap p-Type Semiconductor that has attracted strong interests for transparent electronics. We report here that nanoparticles of this material can also be used as a substitute for the widely used NiO compound to fabricate photocathodes for p-Type dye sensitized solar cells.
