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Title: Heterojunction silicon/indium tin oxide photoelectrodes: development of stable systems in aqueous electrolytes and their applicability to solar energy conversion and storage

Abstract

An approach to circumvent the problem of poor photoelectrochemical (PEC) stability of Si in aqueous electrolytes is the use of heterojunction photoelectrodes comprising the Si/SiO/sub x// indium tin oxide (ITO) structure. As in a Schottky barrier electrode system, the maximum photovoltage attainable with these electrodes is limited by the barrier height at the Si/ITO heterojunction. Both n- and p-Si substrates have been studied. In regenerative PEC systems designed for the conversion of solar energy to electricity, the efficacy of charge transfer at the ITO/electrolyte interface is shown to be a crucial factor. Of the redox electrolytes tested (S/sup 2 -//S/sup 2 -//sub x/,, I/sup 3 -//I/sup -/, (Fe(CN)/sub 6/)/sup 3-/4-/ and Fe/sup 2+/3+/ EDTA), the (Fe(CN)/sup 6//sup 3-/4-/ couple was by far the most efficient in terms of charge transfer across the ITO/electrolyte interface. Optical-to-electrical conversion efficiencies (eta) of 1.57% and 5.7% (approx. AM 1 illumination) were attained for PEC cells based on n- and p-Si substrates, respectively. Detailed tests have revealed long-term stability in (Fe(CN)/sub 6/)/sup 3-/4-/ electrolytes once the ITO film thickness (greater than or equal to 50 A) and solution pH (approx. 12 to 14) were optimized, n-Si/ITO electrodes were used for the photooxidation of Cl/sup -/more » from concentrated LiCl and NaCl electrolytes to illustrate the chemical inertness and stability of these electrodes. Catalytic modification of the ITO surface with RuO/sub 2/ was found to be necessary to sustain Cl/sub 2/ production. Values of eta up to 2.7% were recorded with this PEC system at 100 mW/cm/sup 2/. Finally, the applicability of Si/ITO heterojunction electrodes for the photoassisted splitting of water was demonstrated. Preliminary experiments have revealed a 40% reduction in the threshold voltage required for water photolysis. Catalytic modification of the ITO surface was again a prerequisite for efficient performance of these electrodes.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Colorado State Univ., Fort Collins
OSTI Identifier:
6204289
Resource Type:
Journal Article
Journal Name:
J. Am. Chem. Soc.; (United States)
Additional Journal Information:
Journal Volume: 105:3
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTROLYTES; REGENERATION; PHOTOELECTROCHEMICAL CELLS; OPTIMIZATION; PLATINUM; CATALYTIC EFFECTS; RUTHENIUM OXIDES; WATER; PHOTOLYSIS; EFFICIENCY; INDIUM OXIDES; N-TYPE CONDUCTORS; P-TYPE CONDUCTORS; PH VALUE; PHOTOANODES; PHOTOCATHODES; REACTION KINETICS; REDOX REACTIONS; SILICA; SILICON; SOLAR CELLS; SOLAR ENERGY CONVERSION; STABILITY; TIN OXIDES; ANODES; CATHODES; CHALCOGENIDES; CHEMICAL REACTIONS; CONVERSION; DECOMPOSITION; DIRECT ENERGY CONVERTERS; ELECTROCHEMICAL CELLS; ELECTRODES; ELEMENTS; ENERGY CONVERSION; EQUIPMENT; HYDROGEN COMPOUNDS; INDIUM COMPOUNDS; KINETICS; MATERIALS; METALS; MINERALS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PHOTOCHEMICAL REACTIONS; PHOTOELECTRIC CELLS; PHOTOVOLTAIC CELLS; PLATINUM METALS; RUTHENIUM COMPOUNDS; SEMICONDUCTOR MATERIALS; SEMIMETALS; SILICON COMPOUNDS; SILICON OXIDES; SOLAR EQUIPMENT; TIN COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; TRANSITION ELEMENTS; 400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)

Citation Formats

Hodes, G, Thompson, L, DuBow, J, and Rajeshwar, K. Heterojunction silicon/indium tin oxide photoelectrodes: development of stable systems in aqueous electrolytes and their applicability to solar energy conversion and storage. United States: N. p., 1983. Web. doi:10.1021/ja00341a004.
Hodes, G, Thompson, L, DuBow, J, & Rajeshwar, K. Heterojunction silicon/indium tin oxide photoelectrodes: development of stable systems in aqueous electrolytes and their applicability to solar energy conversion and storage. United States. https://doi.org/10.1021/ja00341a004
Hodes, G, Thompson, L, DuBow, J, and Rajeshwar, K. Wed . "Heterojunction silicon/indium tin oxide photoelectrodes: development of stable systems in aqueous electrolytes and their applicability to solar energy conversion and storage". United States. https://doi.org/10.1021/ja00341a004.
@article{osti_6204289,
title = {Heterojunction silicon/indium tin oxide photoelectrodes: development of stable systems in aqueous electrolytes and their applicability to solar energy conversion and storage},
author = {Hodes, G and Thompson, L and DuBow, J and Rajeshwar, K},
abstractNote = {An approach to circumvent the problem of poor photoelectrochemical (PEC) stability of Si in aqueous electrolytes is the use of heterojunction photoelectrodes comprising the Si/SiO/sub x// indium tin oxide (ITO) structure. As in a Schottky barrier electrode system, the maximum photovoltage attainable with these electrodes is limited by the barrier height at the Si/ITO heterojunction. Both n- and p-Si substrates have been studied. In regenerative PEC systems designed for the conversion of solar energy to electricity, the efficacy of charge transfer at the ITO/electrolyte interface is shown to be a crucial factor. Of the redox electrolytes tested (S/sup 2 -//S/sup 2 -//sub x/,, I/sup 3 -//I/sup -/, (Fe(CN)/sub 6/)/sup 3-/4-/ and Fe/sup 2+/3+/ EDTA), the (Fe(CN)/sup 6//sup 3-/4-/ couple was by far the most efficient in terms of charge transfer across the ITO/electrolyte interface. Optical-to-electrical conversion efficiencies (eta) of 1.57% and 5.7% (approx. AM 1 illumination) were attained for PEC cells based on n- and p-Si substrates, respectively. Detailed tests have revealed long-term stability in (Fe(CN)/sub 6/)/sup 3-/4-/ electrolytes once the ITO film thickness (greater than or equal to 50 A) and solution pH (approx. 12 to 14) were optimized, n-Si/ITO electrodes were used for the photooxidation of Cl/sup -/ from concentrated LiCl and NaCl electrolytes to illustrate the chemical inertness and stability of these electrodes. Catalytic modification of the ITO surface with RuO/sub 2/ was found to be necessary to sustain Cl/sub 2/ production. Values of eta up to 2.7% were recorded with this PEC system at 100 mW/cm/sup 2/. Finally, the applicability of Si/ITO heterojunction electrodes for the photoassisted splitting of water was demonstrated. Preliminary experiments have revealed a 40% reduction in the threshold voltage required for water photolysis. Catalytic modification of the ITO surface was again a prerequisite for efficient performance of these electrodes.},
doi = {10.1021/ja00341a004},
url = {https://www.osti.gov/biblio/6204289}, journal = {J. Am. Chem. Soc.; (United States)},
number = ,
volume = 105:3,
place = {United States},
year = {1983},
month = {2}
}