CdSe Photoanodes for Electrochemical Photovoltaic Conversion

Recently cadmium selenide (CdSe) photoelectrodes attract­ ed interest concerning solar energy conversion because of their good stability and high efficiency. Investigations were per­ formed with CdSe single crystals [1, 2], sintered pellets [3], pastes [4, 5] as well as thin films, obtained by different meth­ ods, e.g. electrochemical deposition [6-8], spray pyrolysis [9], vacuum deposition [10] and growth from solutions [11], The best results with regard to high efficiency (12.4%) are obtained with single n-CdSe crystals in alkaline K3Fe(CN)6/K4Fe(CN)6 electrolyte [1], However, the semiconductor is not stable, showing surface corrosion. Investigations were also carried out using polysulfide electrolytes. The CdSe photoanodes in this case are stable, even under prolonged operation, show­ ing efficiencies up to 8% [1], The aim of the present paper was to investigate the pho­ toelectrochemical properties of a recently described n-CdSe photoanode [12] using an aqueous polysulfide electrolyte.