A superstrate solar cell based on In2(Se,S)3 and CuIn(Se,S)2 thin films fabricated by electrodeposition combined with annealing

Stacked thin films composed of In2(Se,S)3 and CuIn(Se,S)2 layers were grown on a fluorine-doped tin oxide (FTO)-coated glass substrate using electrodeposition of the corresponding selenide (In2Se3 and CuInSe2) precursors followed by annealing in H2S flow (5% in Ar). Structural characterizations of both layers revealed that the resulting film quality strongly depended on annealing conditions of both CuIn(Se,S)2 and In2(Se,S)3 layers: a compact and uniform film was obtained by annealing both layers at 400 °C. Performance of Au/CuIn(Se,S)2/In2(Se,S)3/FTO superstrate-type solar cells also followed these structural characteristics, i.e., a preliminary conversion efficiency of 2.9% was obtained on the device based on 400 °C-annealed In2(Se,S)3 and CuIn(Se,S)2 layers.