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Photochemical conversion of solar energy. Semi-annual progress report, January 1, 1974--June 30, 1974. [Iron--thionine]

Technical Report ·
OSTI ID:5415081
A 1.5% quantum efficiency for conversion of absorbed 578 nm light into electrical power and a 64% quantum efficiency for generating charge carriers have been achieved in an aqueous iron-thionine photogalvanic cell with one illuminated electrode. Under the same conditions efficiency for conversion of incident light into electrical power was 1.7 x 10/sup -3/%. A 0.8% quantum efficiency for conversion of absorbed 578 nm light has been obtained with a thin-layer totally-illuminated (TI) aqueous iron-thionine cell with SnO/sub 2/ and Pt electrodes. With low light intensities a 7.5 x 10/sup -2/% efficiency for power conversion of incident 578 nm light was observed with this cell. Higher outputs were obtained with certain aqueous organic solvents. A 24-unit panel of SnO/sub 2//Pt TI cells was used to operate a motor drawing 0.4 V and 300 ..mu.. amp in sunlight. The second order rate of disproportionation of semithionine, k/sub d/, varies approx. 10/sup 3/ fold with solvent composition in a variety of aqueous-organic solvents; k/sub d/ correlates with Kosower's solvent parameter Z. Association of Fe(II) with thionine could not be detected by a kinetic method, absorption spectrophotometry (200--1800 nm) or paper electrophoresis. The stoichiometry and kinetics of reaction of Fe(III) with leucothionine has been studied in a series of aqueous N,N-dimethylacetamide solvents.
Research Organization:
Boston Univ., Mass. (USA). Dept. of Chemistry
OSTI ID:
5415081
Report Number(s):
NSF/RANN/SE/GI-38103/PR/74/2
Country of Publication:
United States
Language:
English