Ternary chalcogenide-based photoelectrochemical cells IV. Further characterization of the n-CuInS/sub 2//and n-CuInSe/sup 2//aqueous polysulfide systems
The photoelectrochemistry of n-CuInS/sub 2/ and CuInSe/sub 2/ in polysulfide electrolyte is studied with particular emphasis on the pretreatments of the electrodes and on their output stability. The use of Cd doping, (photoelectro) chemical etching, and mild air oxidation all were found to improve electrode performance. The effect of air oxidation was reproducible only for the diselenide, where it improved the fill factor and, because of a negative shift of the flatband potential, the open-circuit voltage. Optimized cells showed, at elevated temperatures, conversion efficiencie around 5 and 7.5% for the sulfide and selenide, respectively. The positive temperature dependence of the photo-I-V characteristics at both low and high illumination intensities, the existence of optimal polysulfide solution compositions, the linear dependence of the photocurrent on the light intensity, and the effects of temperature, solution composition, and initial current density on the photocurrent decrease during the first minute of operation of the cells, are ascribed to limitations of the charge-transfer process across the solid/liquid interface. Thermally activated rates of ad- and desorption of sulfur containing solution species on the semiconductor surface and/or the presence of adsorption-induced electronic states in the bandgap are postulated as causes for this behavior. Notwithstanding these limitations the cells ar resistant to photocorrosion, after the initial decrease is arrested, in contrast to what is known for similar Cd-chalcogenide-based systems. We suggest that this stability, which persists under load and at high light intensities, is due to the strength and character of the bonds in CuIn-dichalcogenides, or to the presence of a top layer of indium oxide in which recombination will take place, or to both.
- Research Organization:
- Department of Structural Chemistry, The Weizmann Institute of Science, Rehovot
- OSTI ID:
- 5281720
- Journal Information:
- J. Electrochem. Soc.; (United States), Journal Name: J. Electrochem. Soc.; (United States) Vol. 132:5; ISSN JESOA
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400 -- Electrochemistry
ADSORPTION
AQUEOUS SOLUTIONS
CADMIUM
CHALCOGENIDES
CHARGE TRANSPORT
CHEMICAL REACTIONS
CHEMISTRY
COPPER COMPOUNDS
COPPER SELENIDES
COPPER SULFIDES
CORROSION RESISTANCE
CRYSTAL DOPING
CURRENTS
DESORPTION
DISPERSIONS
ELECTRIC CURRENTS
ELECTRIC POTENTIAL
ELECTROCHEMICAL CELLS
ELECTROCHEMISTRY
ELECTRODES
ELECTROLYTES
ELEMENTS
EQUIPMENT
ETCHING
ILLUMINANCE
INDIUM COMPOUNDS
INDIUM OXIDES
INDIUM SELENIDES
INDIUM SULFIDES
METALS
MIXTURES
OXIDATION
OXIDES
OXYGEN COMPOUNDS
PHOTOCURRENTS
PHOTOELECTROCHEMICAL CELLS
RECOMBINATION
SELENIDES
SELENIUM COMPOUNDS
SOLAR EQUIPMENT
SOLUTIONS
SORPTION
STABILITY
SULFIDES
SULFUR COMPOUNDS
SURFACE FINISHING
TRANSITION ELEMENT COMPOUNDS