CdS/Sb2S3 heterojunction thin film solar cells with a thermally evaporated absorber†
An antimony sulfide (Sb2S3) semiconductor is appealing as a promising light absorber due to its suitable bandgap (1.5–1.7 eV), ‘one dimensional’ crystal structure and non-toxic constituents. In this work, the orientation preferences of the Sb2S3 thin films grown on the CdS layer and bare glass substrates were compared by SEM and XRD measurements. The growth direction of (Sb4S6)n ribbons was found to be substrate-dependent, and the growth mechanism was discussed. Thin film solar cells in the configuration of glass/(SnO2:F) FTO/CdS/Sb2S3/Au were fabricated and the highest conversion efficiency reached 3.01%. The defects and recombination losses in the thin film solar cells were investigated by voltage-dependent quantum efficiency and time-resolved photoluminescence measurements. The CdS/Sb2S3 (n–p) heterojunction solar cells showed a little decrease by about 0.2% in conversion efficiency to 2.84% after three month storage in ambient air without encapsulation.