The performance of nanocrystalline CuInS2/In2S3/SnO2 heterojunction solar cells prepared by chemical spray pyrolysis

Cu_xIn_2-xS_3-x thin films with various compositions were prepared by chemical spray pyrolysis to investigate Cu-In-S chalcopyrite semiconductor materials for photovoltaic applications. Nanocrystalline grains with sizes ranging from 30 to 80 nm were identified from XRD and SEM measurements. The CuInS₂/In₂S₃/SnO₂ heterojunction was formed to study photovoltaic effects with the sprayed Cu-chalcopyrite thin films. Best results of η=1.32%, V_OC=421 mV, J_SC=5.35 mA/cm² and FF=58.5% were found for solar cells with a Cu_1.1In_0.9S_1.9 absorber layer. Through analysis of the film and device parameters, factors that limited the photovoltaic performance are identified and discussed.