Novel concepts in electrochemical solar cells. Third quarterly progress report, November 15, 1979-January 15, 1980. [Molten salt electrolytes

Abstract

Efforts have been primarily directed toward evaluation of the room temperature molten salt electrolyte in terms of its overall performance for photovoltaic cells. Mass transport processes may prove to be the rate-limiting factor for such electrolytes, unless the concentration of the photo-active redox component can be increased and the solvent viscosity reduced. Acid-base surface chemistry of n-GaAs as occurs in aqueous systems, has been found present and its consequences will be further explored. The selection and optimization of PEC electrolytes is a complex task and we believe that a systems approach would facilitate in identifying the basic electrolyte properties needed. A preliminary analysis reveals that although some of the criteria for an electrolyte are definable precisely, others do require empirical experimentation. It can be concluded that relatively few electrolytes in current use are adequate and it would appear that greater efforts to develop electrolytes would be advantageous. The various types of electrolytes that could be used for PEC's have been identified. Good quality MoSe/sub 2/ single crystals can be grown and short circuit currents greater than previously reported have been achieved in an I/sub 2//I/sup -//Pt cell. A novel technique to produce photo-active films by anodization is being investigated, initially for the formation of polycrystalline MoSe/sub 2/ layers.