The Experts below are selected from a list of 288015 Experts worldwide ranked by ideXlab platform
Jacques Traore - One of the best experts on this subject based on the ideXlab platform.
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Financial Cryptography - Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymoustransferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymityproperty. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
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Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymous transferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymity property. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
Liyuan Han - One of the best experts on this subject based on the ideXlab platform.
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modeling of an equivalent circuit for dye sensitized solar cells Improvement of Efficiency of dye sensitized solar cells by reducing internal resistance
Comptes Rendus Chimie, 2006Co-Authors: Liyuan Han, Naoki Koide, Yasuo Chiba, Ashraful Islam, Takehito MitateAbstract:La resistance interne des piles solaires nanocristallines au TiO 2 sensibilisees par un colorant (DSC) a ete etudiee par spectroscopie d'impedance electrochimique. On a observe quatre elements resistifs dans les spectres d'impedance. Ces resistances peuvent s'expliquer par des variations des parametres de cellule et dependent de la tension de polarisation appliquee. On constate que la resistance liee au transfert de charge a l'interface TiO 2 /colorant/electrolyte se comporte comme une diode, et les resistances en serie correspondent en grande partie a la somme des autres resistances. Pour minimiser la resistance interne dans les piles solaires nanocristallines a colorant, l'influence sur les spectres d'impedance de parametres de cellule tels que la resistance de "feuille" du substrat de verre d'oxydes transparents conducteurs, le facteur de rugosite de la contre-electrode de platine et l'epaisseur de la cellule a ete etudiee. On propose un circuit equivalent pour les piles solaires nanocristallines a colorant a partir de ces resultats. Des efforts conjoints ont conduit a la fabrication d'une pile solaire nanocristalline efficace sensibilisee par un colorant noir. Une densite de photocourant de court-circuit de 20,1 mA/cm 2 , une tension en circuit ouvert de 0,71 V, unfill factor de 0,71 et une efficacite globale de conversion de 10,1 % ont ete obtenues sous un eclairage standard de type AM 1.5 sunlight.
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Improvement of Efficiency of Polymer Solar Cells with Soluble Fullerene Derivatives
2006 IEEE 4th World Conference on Photovoltaic Energy Conference, 2006Co-Authors: Ho-jin Lee, Yasumasa Takeuchi, Liyuan Han, Naoki Koide, Takayuki Arai, Masafumi ShimizuAbstract:Soluble fullerene derivatives, [6,6]-phenyl C61 butyric acid hexyl ester (PCBH) and [6,6]-phenyl C61 butyric acid dodecyl ester (PCBD), were synthesized, and current-voltage (I-V) characteristics of polymer solar cells using these fullerene derivatives were investigated. It is found that PCBH cells show higher short circuit current density (Jsc) than conventional [6,6]-phenyl C61 butyric acid methyl ester (PCBM) cells. Jsc further increases with using high haze TCO substrates and thermal annealing. The Efficiency of 3.3%, 3.8% (aperture illumination area were 1.00 cm2 and 0.25 cm2, respectively) were obtained. Finally the Efficiency of 2.96% (aperture area was 1.001 cm2) was confirmed by a public test center (AIST, JAPAN)
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Improvement of Efficiency of dye-sensitized solar cells based on analysis of equivalent circuit
Journal of Photochemistry and Photobiology A: Chemistry, 2006Co-Authors: Naoki Koide, Yasuo Chiba, Ashraful Islam, Liyuan HanAbstract:Abstract The present paper discusses the principle of dye-sensitized solar cells (DSCs) in terms of a new physics-based equivalent circuit model. This model is proposed following analysis by electrochemical impedance spectroscopy of the voltage dependence of the internal resistance elements of DSCs. The influence of these elements upon cell performance in areas such as short circuit current density (JSC), open circuit voltage (VOC) and fill factor (FF) was examined based on the equivalent circuit. It was demonstrated that the haze factor of TiO2 electrodes is a useful index when fabricating light-confined TiO2 electrodes to improve JSC, and that blocking the TiO2 surface with molecules is an effective way of reducing interfacial charge recombination at the TiO2 surface and of improving shunt resistance and VOC. FF was also improved by reduction of the internal series resistance, which is composed of the following three elements: the redox reaction resistance at the platinum counter electrode, the resistance of carrier transport by ions in the electrolyte, and resistance due to the sheet resistance of the transparent conducting oxide. Finally, the highest Efficiency scores of 10.4% and 10.8% (aperture illumination area 1.004 cm2 and 0.2227 cm2, respectively) were confirmed by a public test center.
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Improvement of Efficiency of dye-sensitized solar cells by reduction of internal resistance
Applied Physics Letters, 2005Co-Authors: Liyuan Han, Naoki Koide, Yasuo Chiba, Ashraful Islam, Ryoichi Komiya, Nobuhiro Fuke, Atsushi Fukui, Ryohsuke YamanakaAbstract:With the aim of increasing conversion Efficiency, the series-internal resistance of dye-sensitized solar cells (DSCs) was investigated with electrochemical impedance spectroscopy measurement based on an equivalent circuit of DSCs. It was found that series-internal resistance correlates positively with the sheet resistance of the transparent conducting oxide and the thickness of the electrolyte layer and negatively with the roughness factor of the platinum counter electrode. A cell sensitized with a black dye with series-internal resistance of 1.8Ωcm2 was fabricated and showed conversion Efficiency of 10.2% when measured with a metal mask under an air mass of 1.5 sunlight.
Sébastien Canard - One of the best experts on this subject based on the ideXlab platform.
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Financial Cryptography - Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymoustransferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymityproperty. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
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Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymous transferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymity property. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
Naoki Koide - One of the best experts on this subject based on the ideXlab platform.
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modeling of an equivalent circuit for dye sensitized solar cells Improvement of Efficiency of dye sensitized solar cells by reducing internal resistance
Comptes Rendus Chimie, 2006Co-Authors: Liyuan Han, Naoki Koide, Yasuo Chiba, Ashraful Islam, Takehito MitateAbstract:La resistance interne des piles solaires nanocristallines au TiO 2 sensibilisees par un colorant (DSC) a ete etudiee par spectroscopie d'impedance electrochimique. On a observe quatre elements resistifs dans les spectres d'impedance. Ces resistances peuvent s'expliquer par des variations des parametres de cellule et dependent de la tension de polarisation appliquee. On constate que la resistance liee au transfert de charge a l'interface TiO 2 /colorant/electrolyte se comporte comme une diode, et les resistances en serie correspondent en grande partie a la somme des autres resistances. Pour minimiser la resistance interne dans les piles solaires nanocristallines a colorant, l'influence sur les spectres d'impedance de parametres de cellule tels que la resistance de "feuille" du substrat de verre d'oxydes transparents conducteurs, le facteur de rugosite de la contre-electrode de platine et l'epaisseur de la cellule a ete etudiee. On propose un circuit equivalent pour les piles solaires nanocristallines a colorant a partir de ces resultats. Des efforts conjoints ont conduit a la fabrication d'une pile solaire nanocristalline efficace sensibilisee par un colorant noir. Une densite de photocourant de court-circuit de 20,1 mA/cm 2 , une tension en circuit ouvert de 0,71 V, unfill factor de 0,71 et une efficacite globale de conversion de 10,1 % ont ete obtenues sous un eclairage standard de type AM 1.5 sunlight.
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Improvement of Efficiency of Polymer Solar Cells with Soluble Fullerene Derivatives
2006 IEEE 4th World Conference on Photovoltaic Energy Conference, 2006Co-Authors: Ho-jin Lee, Yasumasa Takeuchi, Liyuan Han, Naoki Koide, Takayuki Arai, Masafumi ShimizuAbstract:Soluble fullerene derivatives, [6,6]-phenyl C61 butyric acid hexyl ester (PCBH) and [6,6]-phenyl C61 butyric acid dodecyl ester (PCBD), were synthesized, and current-voltage (I-V) characteristics of polymer solar cells using these fullerene derivatives were investigated. It is found that PCBH cells show higher short circuit current density (Jsc) than conventional [6,6]-phenyl C61 butyric acid methyl ester (PCBM) cells. Jsc further increases with using high haze TCO substrates and thermal annealing. The Efficiency of 3.3%, 3.8% (aperture illumination area were 1.00 cm2 and 0.25 cm2, respectively) were obtained. Finally the Efficiency of 2.96% (aperture area was 1.001 cm2) was confirmed by a public test center (AIST, JAPAN)
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Improvement of Efficiency of dye-sensitized solar cells based on analysis of equivalent circuit
Journal of Photochemistry and Photobiology A: Chemistry, 2006Co-Authors: Naoki Koide, Yasuo Chiba, Ashraful Islam, Liyuan HanAbstract:Abstract The present paper discusses the principle of dye-sensitized solar cells (DSCs) in terms of a new physics-based equivalent circuit model. This model is proposed following analysis by electrochemical impedance spectroscopy of the voltage dependence of the internal resistance elements of DSCs. The influence of these elements upon cell performance in areas such as short circuit current density (JSC), open circuit voltage (VOC) and fill factor (FF) was examined based on the equivalent circuit. It was demonstrated that the haze factor of TiO2 electrodes is a useful index when fabricating light-confined TiO2 electrodes to improve JSC, and that blocking the TiO2 surface with molecules is an effective way of reducing interfacial charge recombination at the TiO2 surface and of improving shunt resistance and VOC. FF was also improved by reduction of the internal series resistance, which is composed of the following three elements: the redox reaction resistance at the platinum counter electrode, the resistance of carrier transport by ions in the electrolyte, and resistance due to the sheet resistance of the transparent conducting oxide. Finally, the highest Efficiency scores of 10.4% and 10.8% (aperture illumination area 1.004 cm2 and 0.2227 cm2, respectively) were confirmed by a public test center.
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Improvement of Efficiency of dye-sensitized solar cells by reduction of internal resistance
Applied Physics Letters, 2005Co-Authors: Liyuan Han, Naoki Koide, Yasuo Chiba, Ashraful Islam, Ryoichi Komiya, Nobuhiro Fuke, Atsushi Fukui, Ryohsuke YamanakaAbstract:With the aim of increasing conversion Efficiency, the series-internal resistance of dye-sensitized solar cells (DSCs) was investigated with electrochemical impedance spectroscopy measurement based on an equivalent circuit of DSCs. It was found that series-internal resistance correlates positively with the sheet resistance of the transparent conducting oxide and the thickness of the electrolyte layer and negatively with the roughness factor of the platinum counter electrode. A cell sensitized with a black dye with series-internal resistance of 1.8Ωcm2 was fabricated and showed conversion Efficiency of 10.2% when measured with a metal mask under an air mass of 1.5 sunlight.
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Improvement of Efficiency of dye-sensitized solar cells by reduction of internal resistance
Conference Record of the Thirty-first IEEE Photovoltaic Specialists Conference 2005., 1Co-Authors: Naoki Koide, Yasuo Chiba, Ashraful Islam, Ryoichi Komiya, Nobuhiro Fuke, Atsushi Fukui, Ryosuke Yamanaka, Liyuan ManAbstract:In order to elevate conversion Efficiency, the series-internal resistance of dye-sensitized solar cells (DSCs) was investigated with electrochemical impedance spectroscopy measurement based on an equivalent circuit of DSCs. It was found that series-internal resistance correlates negatively with the roughness factor of the platinum counter electrode and positively with the thickness of the electrolyte layer. A cell sensitized with a black dye with series-internal resistance of 1.8 /spl Omega/cm/sup 2/ was fabricated and showed conversion Efficiency of 10.2%, which was confirmed at the National Institute of Advanced Industrial Science and Technology (AIST, Japan).
Aline Gouget - One of the best experts on this subject based on the ideXlab platform.
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Financial Cryptography - Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymoustransferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymityproperty. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
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Improvement of Efficiency in (Unconditional) Anonymous Transferable E-Cash
Financial Cryptography and Data Security, 2008Co-Authors: Sébastien Canard, Aline Gouget, Jacques TraoreAbstract:The practical advantage expected from transferable e-cash compare to non-transferable is the significant reduction of the interaction number between the bank and the users. However, this property is not fulfilled by anonymous transferable e-cash schemes of the state-of-the art. In this paper, we first present a transferable e-cash scheme with a reduced number of communications between the bank and the users that fulfils the computational anonymity property. Next, we present a transferable e-cash scheme with a reduced interaction number that fulfils the unconditional anonymity. This latter scheme is quite less efficient.
