Photoelectrochemical water splitting by tandem type and heterojunction amorphous silicon electrodes

1988 ◽  
Vol 66 (8) ◽  
pp. 1853-1856 ◽  
Author(s):  
Yuichi Sakai ◽  
Satoshi Sugahara ◽  
Michio Matsumura ◽  
Yoshihiro Nakato ◽  
Hiroshi Tsubomura
Keyword(s):  
Sulfuric Acid ◽  
Amorphous Silicon ◽  
Hydrogen Evolution ◽  
Water Splitting ◽  
Hydrogenated Amorphous Silicon ◽  
Chemical Conversion ◽  
External Bias ◽  
P Type ◽  
Conversion Efficiencies ◽  
Hydrogenated Amorphous

The tandem type hydrogenated amorphous silicon (a-Si) electrode having an [n–i–p–n–i–p] structure and a similar tandem a-Si electrode having [n–i–p–n–i–p–n] layers deposited on p-type crystalline Si showed cathodic photocurrents accompanied by hydrogen evolution starting at potentials 1.67 and 2.08 V, respectively, more positive than the thermodynamic hydrogen evolution potential in a sulfuric acid solution. These electrodes, when connected to an RuO2 counterelectrode, caused sustained water splitting without external bias, giving solar-to-chemical conversion efficiencies of 1.98% and 2.93%, respectively, under simulated AM 1, 100 mW cm−2 solar radiation. These efficiencies are critically compared with the efficiency of another type of solar photoelectrolysis of water, namely, the electrolysis of water by the electrical output from solid-state solar cells.

Role of Hydrogen Microstructure in Amorphous Silicon

1992 ◽  
Vol 258 ◽  
Author(s):  
Sufi Zafar ◽  
E. A. Schiff
Keyword(s):  
Amorphous Silicon ◽  
Hydrogen Evolution ◽  
Hydrogen Diffusion ◽  
Hydrogenated Amorphous Silicon ◽  
Hydrogenated Amorphous ◽  
Unified Description

ABSTRACTA model for correlating the observed properties of hydrogenated amorphous silicon (a-Si:H) with the underlying hydrogen microstructure is reviewed. The model provides a unified description of defect equilibration, hydrogen evolution, rehydrogenation and hydrogen diffusion measurements.

Transient Mean-Field Reaction-Diffusion Model Applied to Hydrogen Evolution From Hydrogenated Amorphous Silicon

1995 ◽  
Vol 377 ◽  
Author(s):  
A. J. Franzi ◽  
M. Mavrikakis ◽  
J. W. Schwank ◽  
J. L. Gland
Keyword(s):  
Amorphous Silicon ◽  
Hydrogen Evolution ◽  
Diffusion Model ◽  
Mean Field ◽  
Hydrogenated Amorphous Silicon ◽  
Reaction Diffusion ◽  
Reaction Diffusion Model ◽  
Wide Range ◽  
Field Reaction ◽  
Hydrogenated Amorphous

ABSTRACTHydrogen bulk mobility plays an important role in determining a wide range of materials and electronic properties of hydrogenated amorphous silicon (a-Si:H). The existence of two types of hydrogen traps plays an important role in controlling hydrogen mobility in, and evolution of hydrogen from a-Si:H, however, theoretical and experimental literature values for the trap energetics vary considerably. We have developed a mean-field reaction-diffusion model which explicitly includes two trap states and realistic surface processes to model hydrogen evolution from a-Si:H. Modern numerical techniques were required to solve this challenging problem over the wide range of temperatures and concentrations encountered in typical hydrogen evolution experiments. The model is based on a number of experimentally established parameters. Comparison of our rigorous model with temperature programmed hydrogen evolution experiments provides a powerful method for characterizing the energetics, trap concentrations and diffusivity of hydrogen in a-Si:H.

Semiconducting Polymer and Hydrogenated Amorphous Silicon Heterojunction Solar Cells

2011 ◽  
Vol 1321 ◽  
Author(s):  
A. R. Middya ◽  
Eric A. Schiff
Keyword(s):  
Solar Cells ◽  
Amorphous Silicon ◽  
Photovoltaic Effect ◽  
Hydrogenated Amorphous Silicon ◽  
Hybrid Solar Cells ◽  
Semiconducting Polymer ◽  
Heterojunction Solar Cells ◽  
P Type ◽  
Hydrogenated Amorphous ◽  
Silicon Heterojunction Solar Cells

ABSTRACTIn this work, we report on investigation of p-type semiconducting polymer, {poly(3,4 polyethylenedioxythiophene)-poly(styrenesulfonate)} (PEDOT:PSS) as the p-layer in NIP and PIN hydrogenated amorphous silicon (a-Si:H) solar cells. The rectification ratio of solution-casted diode is ∼ 10, it increases to 3×104 when PEDOT:PSS is deposited by Spin Coating technique. We observed additional photovoltaic effect when light is illuminated through polymer side. So far, best solar cells characteristics observed for PEDOT:PSS/a-Si:H hybrid solar cells are Voc ≈ 720 mV and Jsc ≈ 1 - 2 mA/cm2.

Boron doping in a-SiO:H,

2014 ◽  
Vol 92 (7/8) ◽  
pp. 586-588 ◽  
Author(s):  
Y. Kitani ◽  
T. Maeda ◽  
S. Kakimoto ◽  
K. Tanaka ◽  
R. Okumoto ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Hole Mobility ◽  
Boron Doping ◽  
Type A ◽  
Dark Conductivity ◽  
Wide Range ◽  
P Type ◽  
Hydrogenated Amorphous ◽  
Silicon Oxygen

Boron-doping characteristics in hydrogenated amorphous silicon–oxygen alloys (a-SiO:H) have been studied in contrast to those in hydrogenated amorphous silicon (a-Si:H). Although the boron-incorporation efficiency shows almost the same value between a-SiO:H and a-Si:H, p-type a-SiO:H (p-a-SiO:H) exhibits lower dark conductivity by one or two orders of magnitude as compared to p-type a-Si:H (p-a-Si:H) in a wide range of doping levels. We have found that p-a-SiO:H exhibits low dark conductivity as compared to p-a-Si:H even when we choose samples showing the same activation energy from a variety of as-deposited and thermally annealed samples. We have concluded from the different Urbach-energy values between high quality intrinsic a-SiO:H and a-Si:H that the origin of low dark conductivity in p-a-SiO:H is due to low hole mobility.

Kinetics Of Hydrogen Evolution And Crystallization In Hydrogenated Amorphous Silicon Films Studied By Thermal Analysis And Raman Scattering

1993 ◽  
Vol 321 ◽  
Author(s):  
Nagarajan Sridhar ◽  
D. D. L. Chung ◽  
W. A. Anderson ◽  
W. Y. Yu ◽  
L. P. Fu ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Raman Scattering ◽  
Amorphous Silicon ◽  
Hydrogen Evolution ◽  
Deposition Temperature ◽  
Evolved Gas Analysis ◽  
Silicon Film ◽  
Hydrogenated Amorphous Silicon ◽  
Film Deposition ◽  
Hydrogenated Amorphous

ABSTRACTWe observed the processes of hydrogen evolution and crystallization in hydrogenated Amorphous silicon 0.5–7 μm thick films (deposited by dc glow discharge on Molybdenum) by differential scanning calorimetry (DSC), Raman scattering and thermogravimetric analysis (TGA). Investigation was made as a function of doping, deposition temperature and film thickness. For all the films, an endothermic DSC peak was observed at 694 °C (onset). That this peak was at least partly due to hydrogen evolution was shown by TGA, which showed weight loss beginning at 694 °C, and by evolved gas analysis, which showed hydrogen evolution at 694 °C. This temperature (658–704 °C) increased with increasing heating rate (5–30 °C/min). Doping reduced this temperature from 694 to 625 °C for boron doping and to 675 °C for phosphorous doping. Hydrogen evolution kinetics and FTIR results suggest that the silicon-hydrogen bonding in the intrinsic film was a mixture of SiH and S1H2, and was predominantly SiH in the phosphorous doped films and SiH2 in the boron doped films. Crystallization was independent of silicon-hydrogen bonding in the as-deposited Amorphous silicon film. It was bulk (not interface) induced. No exothermic DSC peak accompanied the crystallization. The film deposition temperature had little effect on the DSC result, but crystallization was enhanced by a higher deposition temperature.

Dangling-Bond Relaxation and Metastability in P-Type Hydrogenated Amorphous Silicon

1995 ◽  
Vol 377 ◽  
Author(s):  
Richard S. Crandall ◽  
Martin W. Carlen ◽  
Klaus Lips ◽  
Yueqin Xu
Keyword(s):  
Elevated Temperature ◽  
Amorphous Silicon ◽  
Hydrogenated Amorphous Silicon ◽  
Type A ◽  
Dangling Bond ◽  
Dangling Bonds ◽  
Hole Trapping ◽  
P Type ◽  
Hydrogenated Amorphous

ABSTRACTWe discuss the subtle effects involved in observing slow dangling bond relaxation by studying capacitance transients in p-type hydrogenated amorphous silicon (a-Si:H). The data suggest that neutral dangling bonds are reversibly converted into metastable positive charged dangling bonds by hole trapping. These metastable positive dangling bonds reconvert to neutral dangling bonds upon annealing at elevated temperature. The annealing kinetics for this process are the same as those observed for annealing of quenched in conductivity changes in p-type a-Si:H.

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