Electrodeposited p-type Cu2O thin films at high pH for all-oxide solar cells with improved performance.

Abstract We report the electrodeposition of cuprous oxide (Cu 2 O) films from cupric sulfate-lactate electrolytes at high pH 13.5 and their performance in all-oxide fluorine-doped tin oxide/Cu 2 O/aluminium-doped zinc oxide solar cells. The deposit grains are found to grow with rather randomly distributed <111> and <100> crystal orientations and have a poorly-definded morphology with evidence of chemical dissolution that takes place during the deposition process. Significant improvements in the solar cell performance with high power conversion efficiencies of up to 1.55% is achieved, which is much better that those (<0.2%) of solar cells with Cu 2 O layer electrodeposited at lower pH. The performance enhancement is primarily attributed to the improved electron transport in the Cu 2 O thin film due to partial merging of grains. Highlights • Cu 2 O electrodeposited at pH 13.5 has poorly-defined grains with mixed orientations. • Chemical dissolution becomes significant at high electrodeposition pH. • Solar cell performance is improved with partially merged grains. • Optimal power conversion efficiency of ~1.55% is obtained. • Cu 2 O with poorly-defined grains has high electron mobility. [ABSTRACT FROM AUTHOR]