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Title: Electrochemical photovoltaic cells. Project 65021 quarterly technical progress report, July 15-October 15, 1979

Technical Report ·
DOI:https://doi.org/10.2172/5430105· OSTI ID:5430105

During the second quarter of this program we have evaluated the photoelectrochemical performance of single-crystal MoSe/sub 2/ and GaAs, polycrystalline CdSe, and cells with RbAg/sub 4/I/sub 5/ solid electrolyte. MoSe/sub 2/ electrode exhibited very good photoresponse in electrolytes containing Br/sup -//Br/sub 2/ redox couple. The photopotential and photocurrent were larger in acid than in alkaline electrolyte. A power conversion efficiency of about 5% was achieved under 200 mW/cm/sup 2/ Xenon light illumination in the acid medium. The catalytic activity of a platinized platinum electrode toward Br/sup -//Br/sub 2/ redox couple was also better in acid electrolyte than in alkaline electrolyte. Higher current densities were obtained in the acid medium. The MoSe/sub 2/ was found to have good stability in acid and alkaline electrolytes; however, it will be necessary to protect the electrolyte against evaporation of the bromine, oxidation by air, or photodecomposition. GaAs was tested in alkaline electrolytes containing Se/sup 2 -//Se/sub n//sup 2 -/, I/sup -//I/sub 2/ or Br/sup -//Br/sub 2/ redox couple and in acid electrolytes containing Fe/sup +2//Fe/sup +3/, Cr/sup +2//Cr/sup +3/, Sn/sup +2//Sn/sup +4/, Cu/sup +1//Cu/sup +2/, Ti/sup +3//Ti/sup +4/, I/sup -//I/sub 2/ or Br/sup -//Br/sub 2/. Large anodic dark currents were observed in solutions containing Sn/sup +2//Sn/sup +4/ or Cu/sup +1//Cu/sup +2/. The large photoeffects found with the other redox couples were usually accompanied by electrode darkening and decrease in photocurrent with time. Polycrystalline electrodes have been made by thermal vacuum evaporation of CdSe on titanium foil or SnO/sub 2/-coated glass. The CdSe still suffered from poor adherence to the substrates and, therefore, poor photoresponse. A solid electrolyte photoelectrochemical cell was fabricated giving photopotentials of about 300 mV at current densities of about 0.1 mA/cm/sup 2/ under 200 mW/cm/sup 2/ Xenon light illumination.

Research Organization:
Institute of Gas Technology, Chicago, IL (United States)
DOE Contract Number:
EG-77-C-01-4042
OSTI ID:
5430105
Report Number(s):
DSE-4042-T8
Country of Publication:
United States
Language:
English