Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which shoul...Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which should possess small bandgap to ensure wide light harvest, facile charge separation to allow the generated photocharges migrating to the reactive sites and highly catalytic capability to fully utilize the separated photocharges. Proper electrode fabrication method is of equal importance for promoting charge transfer and accelerating surface reactions in the electrodes. Moreover,powerful characterization method can shed light on the complex PEC process and provide deep understanding of the rate-determining step for us to improve the PEC systems further. Targeting on high solar conversion efficiency, here we provide a review on the development of PEC water splitting in the aspect of materials exploring, fabrication method and characterization. It is expected to provide some fundamental insight of PEC and inspire the design of more effective PEC systems.展开更多
We confirmed methyl termination on n-Si(111) surface by ATR-FTIR measurement, which was fabricated by a photo chloro-reaction and its methylation. The coverage of the methylation was about 63.7%, and the surface was n...We confirmed methyl termination on n-Si(111) surface by ATR-FTIR measurement, which was fabricated by a photo chloro-reaction and its methylation. The coverage of the methylation was about 63.7%, and the surface was not re-terminated by hydrogen. Photoelectrochemical properties of the n-Si(111) were measured as an electrode for a photoelectrochemical cell, and an onset potential obtaining photocurrent for the methyl terminated n-Si(111) electrode was observed as negative shift at 70 mV comparing with that of the hydrogen terminated n-Si(111) electrode. Therefore, the negative shift would be expected for improving open circuit voltage towards solar cell.展开更多
Application of semiconductor particles has been noticed to solve energy problems as photocatalysis for O2 evolution in water splitting etc. We are trying fabrication of semiconductor electrode by n-WO3 particle toward...Application of semiconductor particles has been noticed to solve energy problems as photocatalysis for O2 evolution in water splitting etc. We are trying fabrication of semiconductor electrode by n-WO3 particle toward O2 evolution in water splitting. The electrode obtained high photooxidation properties of water as preventing effective recombination between electrons and holes by utilizing fine semiconductor particles. Particularly, application of suspension prepared by ball milling was able to obtain fine n-WO3 thin film and the remarked semiconductor properties.展开更多
Since hydrogen-terminated Si surface has hydrophobicity, it is expected that adsorbed monomolecular film of surfactant will be formed on the Si surface in aqueous solution containing the surfactant. Such an adsorbed m...Since hydrogen-terminated Si surface has hydrophobicity, it is expected that adsorbed monomolecular film of surfactant will be formed on the Si surface in aqueous solution containing the surfactant. Such an adsorbed monolayer film is very effective for the development of a functional electrode. In this study, we have investigated the state of adsorption about an aerosol OT as the monolayer on the electrode surface and its orientation with hydrogen-terminated Si(111) surface by in situ ATR-FTIR spectroscopy. At this time, in situ observation performed while imposing bias to the electrode. The results suggested that the aerosol OT were desorbed by the oxidation of back-bonds in the Si atoms on the electrode surface under the imposing noble potential, although no change was observed especially when imposing less-noble potential.展开更多
We investigate the effect of a metallic electrode on the ability for poly[2-methoxy-5-（2＇-ethylhexyloxy）-1,4- phenylene vinylene] （MEH-PPV） film to undergo amplified spontaneous emission （ASE）. The threshold of...We investigate the effect of a metallic electrode on the ability for poly[2-methoxy-5-（2＇-ethylhexyloxy）-1,4- phenylene vinylene] （MEH-PPV） film to undergo amplified spontaneous emission （ASE）. The threshold of the device with Ag cladding is about 10 times greater than that of a metal-free device, but metal such as Al completely shuts off ASE. The ASE recurs when a thin spacer layer, such as a few nanometers of SiO2, is introduced between the MEH-PPV film and the Al cladding. Compared with the Cu or Al electrode, the Ag cladding is most suited to serve as an electrode with its low optical loss due to its high work-function and reflectivity.展开更多
The photoelectric properties of the lattice-matched GaAs/AlxGa1-xAs quantum well electrodes and the influence of the electrode structure such as well width, the thickness of outer barrier and the number of period were...The photoelectric properties of the lattice-matched GaAs/AlxGa1-xAs quantum well electrodes and the influence of the electrode structure such as well width, the thickness of outer barrier and the number of period were studied in a nonaqueous electrolyte. A new kind of structure of multiple quantum well electrode with varied well width, possessing the quantum yield three times that of GaAs bulk materials, was designed and fabricated.展开更多
n-Si（111） surface tailed -C2H5, -C2H4COOH, -C2H2COOH were prepared by the reactions among Si-H to ethyl-Grignard, methyl acrylate and ethyl propionate, and the carboxyls were formed under the existence of trifluoroa...n-Si（111） surface tailed -C2H5, -C2H4COOH, -C2H2COOH were prepared by the reactions among Si-H to ethyl-Grignard, methyl acrylate and ethyl propionate, and the carboxyls were formed under the existence of trifluoroacetic acid. The composite n-Si（111） electrodes were obtained by depositing Pt nanodots and the photovoltaic characteristics for these electrodes were studied in I^-/I3^- redox electrolyte. The j-U （photo current density-potential） behaviors of photo-voltage and photocurrent densities to the electrodes under solar illumination varied regularly with groups of -C2H2COOH〉-C2H4COOH〉-H〉-C2H5. The photo-voltage and photocurrent density of the electrode tailed -C2 H2COOH were -0.641 V and 5.25 mA/cm^2, respectively, more negative than those of the non-conjugated modification.展开更多
基金supported by the Australian Research Council through its Discovery Project (DP)Federation Fellowship (FF) Program
文摘Photoelectorchemical（PEC） water splitting is an attractive approach for producing sustainable and environment-friendly hydrogen. An efficient PEC process is rooted in appropriate semiconductor materials, which should possess small bandgap to ensure wide light harvest, facile charge separation to allow the generated photocharges migrating to the reactive sites and highly catalytic capability to fully utilize the separated photocharges. Proper electrode fabrication method is of equal importance for promoting charge transfer and accelerating surface reactions in the electrodes. Moreover,powerful characterization method can shed light on the complex PEC process and provide deep understanding of the rate-determining step for us to improve the PEC systems further. Targeting on high solar conversion efficiency, here we provide a review on the development of PEC water splitting in the aspect of materials exploring, fabrication method and characterization. It is expected to provide some fundamental insight of PEC and inspire the design of more effective PEC systems.
文摘We confirmed methyl termination on n-Si(111) surface by ATR-FTIR measurement, which was fabricated by a photo chloro-reaction and its methylation. The coverage of the methylation was about 63.7%, and the surface was not re-terminated by hydrogen. Photoelectrochemical properties of the n-Si(111) were measured as an electrode for a photoelectrochemical cell, and an onset potential obtaining photocurrent for the methyl terminated n-Si(111) electrode was observed as negative shift at 70 mV comparing with that of the hydrogen terminated n-Si(111) electrode. Therefore, the negative shift would be expected for improving open circuit voltage towards solar cell.
文摘Application of semiconductor particles has been noticed to solve energy problems as photocatalysis for O2 evolution in water splitting etc. We are trying fabrication of semiconductor electrode by n-WO3 particle toward O2 evolution in water splitting. The electrode obtained high photooxidation properties of water as preventing effective recombination between electrons and holes by utilizing fine semiconductor particles. Particularly, application of suspension prepared by ball milling was able to obtain fine n-WO3 thin film and the remarked semiconductor properties.
文摘Since hydrogen-terminated Si surface has hydrophobicity, it is expected that adsorbed monomolecular film of surfactant will be formed on the Si surface in aqueous solution containing the surfactant. Such an adsorbed monolayer film is very effective for the development of a functional electrode. In this study, we have investigated the state of adsorption about an aerosol OT as the monolayer on the electrode surface and its orientation with hydrogen-terminated Si(111) surface by in situ ATR-FTIR spectroscopy. At this time, in situ observation performed while imposing bias to the electrode. The results suggested that the aerosol OT were desorbed by the oxidation of back-bonds in the Si atoms on the electrode surface under the imposing noble potential, although no change was observed especially when imposing less-noble potential.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60978061,60777026,60677007,60825407,and 61036007)the Program for New Century Excellent Talents in University,China (Grant No. NCET-08-0717)+1 种基金the Beijing Municipal Science and Technology Commission (Grant Nos. Z090803044009001 and 4102046)the Program of Introducing Talents of Discipline to Universities,China (Grant No. B08002)
文摘We investigate the effect of a metallic electrode on the ability for poly[2-methoxy-5-（2＇-ethylhexyloxy）-1,4- phenylene vinylene] （MEH-PPV） film to undergo amplified spontaneous emission （ASE）. The threshold of the device with Ag cladding is about 10 times greater than that of a metal-free device, but metal such as Al completely shuts off ASE. The ASE recurs when a thin spacer layer, such as a few nanometers of SiO2, is introduced between the MEH-PPV film and the Al cladding. Compared with the Cu or Al electrode, the Ag cladding is most suited to serve as an electrode with its low optical loss due to its high work-function and reflectivity.
基金Project supported by the National Natural Science Foundation of China.
文摘The photoelectric properties of the lattice-matched GaAs/AlxGa1-xAs quantum well electrodes and the influence of the electrode structure such as well width, the thickness of outer barrier and the number of period were studied in a nonaqueous electrolyte. A new kind of structure of multiple quantum well electrode with varied well width, possessing the quantum yield three times that of GaAs bulk materials, was designed and fabricated.
基金We are grateful to the Project of the National Natural Science Foundation of China(Grant No.50602004)the support from Chinese Education for Back Student Abroad and the fund for Young Teacher of BUCT(Project No.QN0512)for financial support.
文摘n-Si（111） surface tailed -C2H5, -C2H4COOH, -C2H2COOH were prepared by the reactions among Si-H to ethyl-Grignard, methyl acrylate and ethyl propionate, and the carboxyls were formed under the existence of trifluoroacetic acid. The composite n-Si（111） electrodes were obtained by depositing Pt nanodots and the photovoltaic characteristics for these electrodes were studied in I^-/I3^- redox electrolyte. The j-U （photo current density-potential） behaviors of photo-voltage and photocurrent densities to the electrodes under solar illumination varied regularly with groups of -C2H2COOH〉-C2H4COOH〉-H〉-C2H5. The photo-voltage and photocurrent density of the electrode tailed -C2 H2COOH were -0.641 V and 5.25 mA/cm^2, respectively, more negative than those of the non-conjugated modification.
