Composition Control of a Light Absorbing Layer of CuInSe2 Thin Film Solar Cells Prepared by Electrodeposition

Abstract

Thin light-active layers of the CuInSe2 solar cell were prepared on Mo-coated sodalime glass substrates by one-step electrodeposition and post-annealing. The structure, morphology, and composition of CuInSe2 film could be controlled by deposition parameters, such as the composition of metallic precursors, the concentration of complexing agents, and the temperature of post-annealing with elemental selenium. A dense and uniform Cu-poor CuInSe2 film was successfully obtained in a range of parametric variation of electrodeposition with a constant voltage of –0.5 V vs. a Ag/AgCl reference electrode. The post-annealing of the film at high temperature above 500℃ induced crystallization of CuInSe2 with well-developed grains. The KCN-treatment of the annealed CuInSe2 films further induced Cu-poor CuInSe2 films without secondary phases, such as Cu2Se. The structure, morphology, and composition of CuInSe2 films were compared with respect to the conditions of electrodeposition and post-annealing using SEM, XRD, Raman, AES and EDS analysis. And the conditions for preparing device-quality CuInSe2 films by electrodeposition were proposed.