Characterization of the polycrystalline n-CuInSe/sub 2/-indium oxide/polyiodide junction by electrolyte electroreflectance, cyclic voltammetry, and scanning electron microscopy
It is well known that stable and efficient liquid-junction photovoltaic solar cells based on n-CuInSe/sub 2/ photoanodes can be obtained by coating the semiconductor surface with an indium-oxide layer and by employing an aqueous polyiodide solution containing Cu/sup +/, In/sup 3+/, and H/sup +/ ions. In this work, the authors further investigated the polycrystalline n-CuInSe/sub 2/-indium oxide/polyiodide junction using electrolyte electroreflectance and cyclic voltammetry. The effect of the indium-oxide overcoat on the semiconductor flatband potential in solutions having different pH values was studied by monitoring the whole specimen surface and small surface areas. Indium is found to be preferentally electrodeposited at surface defects and at zones of high electrical conductivity, while insulating areas (low doped crystallites) remain uncovered. This explains the lack of homogeneity of the In-oxide layer generated by thermal oxidation of the electrodeposited In. The flatband potential of the surface areas covered with indium oxide is reasonably more affected by electrolyte rhoH changes than that of uncovered zones. Finally, the influence of rhoH on the electroreduction efficiency of dissolved anions was investigated on both etched and In-oxide covered CuInSe/sub 2/ electrodes by cyclic voltammetry. The experimental fact that at acidic media, the electroreduction kinetics of anions I/sub 3//sup -/ is enhanced, is consistent with the observed rhoH dependence of the flatband potential and explains the photostabilizing effect of indium-oxide overcoating in H/sup +/ containing electrolytes.
- Research Organization:
- Centro di Studio sui Processi Elettrodici del CNR, Dipartimento di Chimica Fisica Applicata del Politecnico, Piazza L. da Vinci, 32, 20133 Milano (IT)
- OSTI ID:
- 7132502
- Journal Information:
- J. Electrochem. Soc.; (United States), Vol. 135:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
INDIUM OXIDES
ELECTRIC CONDUCTIVITY
SURFACE COATING
PHOTOVOLTAIC CELLS
DESIGN
CHEMICAL REACTION KINETICS
COPPER ALLOYS
ELECTRODES
JUNCTION DIODES
MATERIALS TESTING
OPTICAL PROPERTIES
PH VALUE
PHOTODIODES
POLYCRYSTALS
SCANNING ELECTRON MICROSCOPY
SELENIUM OXIDES
SEMICONDUCTOR MATERIALS
SOLUTIONS
VOLTAMETRY
ALLOYS
CHALCOGENIDES
CRYSTALS
DEPOSITION
DIRECT ENERGY CONVERTERS
DISPERSIONS
ELECTRICAL PROPERTIES
ELECTRON MICROSCOPY
INDIUM COMPOUNDS
KINETICS
MATERIALS
MICROSCOPY
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHYSICAL PROPERTIES
REACTION KINETICS
SELENIUM COMPOUNDS
SEMICONDUCTOR DEVICES
SEMICONDUCTOR DIODES
TESTING
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360601 - Other Materials- Preparation & Manufacture
360603 - Materials- Properties
656003 - Condensed Matter Physics- Interactions between Beams & Condensed Matter- (1987-)
400201 - Chemical & Physicochemical Properties