Fabricating over 7%-efficient Sb2(S,Se)3 thin-film solar cells by vapor transport deposition using Sb2Se3 and Sb2S3 mixed powders as the evaporation source

Abstract In this study, Sb2(S,Se)3 thin films are fabricated using the vapor transport deposition (VTD) method, with Sb2Se3 and Sb2S3 mixed powders as the evaporation source. The performance of the corresponding glass/ITO/CdS/Sb2(S,Se)3/Au solar cells are found to be correlated to the mass ratio between Sb2S3 and the overall powder mixture. The properties of the Sb2(S,Se)3 thin films and cell devices adopting four different Sb2S3 mass ratios (x = 0.1, 0.25, 0.5 and 0.75) are compared. Further, the electrical properties – from dark and light J-V measurements; structural properties – from X-ray diffraction and scanning electron microscope measurements; and carrier-recombination rates at the buffer/absorber interface in the space-charge region (SCR) and in the quasi-neutral region – from temperature-illumination-dependent open-circuit voltage (VOC) measurements – are compared. It is found that a Sb2(S,Se)3 solar cell with a Sb2S3 mass ratio of 0.25 had optimal crystallinity, the lowest density of deep traps and the smallest carrier-recombination rates at the interface, leading to a high efficiency of 7.31%.