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

Photoelectrochemical (PEC) solar cells have been fabricated using an aqueous poly-iodide solution electrolyte and thin-film photoelectrodes in the form of vacuum flash-evaporated thin films of 0.1% indium-doped CdSe0.7Te0.3 semiconducting photovoltaic alloy as one of the electrodes. For this, thin films 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 6.5×10−5 mbar. The counter electrode was graphite. Different thickness films were deposited in separate depositions to study the effect of thickness on the solar cell efficiency. Also, some of the films were given different surface and heat treatments, viz. etching, photoetching and annealing, to study the effect of annealing and surface 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. The increase in efficiency was between 80 and 100%. An approximate six-fold increase in the thickness of the thin-film electrodes also led to an increase in efficiency of up to 80%. The results of the investigations are discussed and explained.