Fabrication and characterization of photoelectrochemical (PEC) solar cellsbased on 0.1% indium-doped CdSe0.7Te0.3 thin-film electrode

Photoelectrochemical (PEC) solar cells have been fabricated using an aqueou s poly-iodide solution electrolyte and thin-film photoelectrodes in the for m of vacuum flash-evaporated thin films of 0.1% indium-doped CdSe0.7Te0.3 s emiconducting photovoltaic alloy as one of the electrodes. For this, thin f ilms of the CdSe0.7Te0.3 alloy were prepared by vacuum flash-evaporation of the bulk alloy ingot powder on thoroughly cleaned glass substrates held at room temperature in a vacuum of 6.5 X 10(-5) mbar. The counter electrode w as graphite. Different thickness films were deposited in separate depositio ns to study the effect of thickness on the solar cell efficiency. Also, som e of the films were given different surface and heat treatments, viz. etchi ng, photoetching and annealing, to study the effect of annealing and surfac e treatments on the efficiency of the solar cells formed using these films as photoelectrodes. It was found that the PEC solar cells formed exhibited an increase in efficiency of the conversion of light into electrical energy when the thin-film electrodes were annealed. etched or/and photoetched. Th e increase in efficiency was between 80 and 100%. An approximate six-fold i ncrease in the thickness of the thin-film electrodes also led to an increas e in efficiency of up to 80%. The results of the investigations are discuss ed and explained. (C) 2001 Elsevier Science B.V. All rights reserved.