Efficiency of some iron-thionine photogalvanic cells

Abstract

Rabinowitch has suggested that the photogalvanic effect might be used to convert sunlight into electricity. In order to explore this suggestion, some photogalvanic cells using the iron-thionine system as the photosensitive fluid were built and tested. The observed maximum power conversion efficiency was 3 × 10−4 per cent, based on light absorbed. The principal reason for the low efficiency was shown to be polarization of the polished platinum electrodes. Coating the electrodes with platinum black reduced polarization sufficiently, so that it appeared possible to achieve an efficiency of 6 × 10−2 per cent, although this value was not actually observed. In principle, it appeared possible to make further increases in efficiency by increasing electrode area and decreasing the electrolyte resistance. Aside from electrode polarization, the major problem encountered was the rapid loss of the photochemical activity of the dye. No further progress can be made until this problem is solved.