Influence of the Ammonia Concentration in Chemical Bath Deposition and Selenourea Concentration in Hydrothermal Process on the Properties of CdS and Sb2S3−ySey Thin Films and the Photovoltaic Performance of the Corresponding Solar Cells

Abstract

To explore the feasibility of the flexible Sb2S3−ySey thin‐film solar cell fabrication using polyimide thin films as substrates, CdS thin films are prepared on SnO2:F conducting glass (FTO) substrates by decreasing the ammonia concentration of chemical bath deposition, and Sb2S3−ySey thin films are grown on the FTO/CdS substrate by changing the selenourea concentration of hydrothermal process. The influence of the ammonia and selenourea concentration on properties of CdS and Sb2S3−ySey is systematically investigated and solar cells with the architecture of FTO/CdS/Sb2S3−ySey/spiro‐OMeTAD/Au are fabricated. For CdS thin films on FTO substrate, the thickness decreases and roughness increases with the decrease of ammonia concentration in chemical bath deposition. The compact and full‐coverage CdS thin films with thickness of 50 ± 6 nm are successfully obtained using the low ammonia concentration (0.59 m). For Sb2S3−ySey thin films on FTO/CdS substrate, the Se:S:Sb atomic ratio and thickness increases with the increase of selenourea concentration in hydrothermal process. The optimal selenourea concentration is 6 mM. The solar cells with the 50 ± 6 nm thick CdS thin film and Sb2S2.10Se0.56 thin film achieve photoelectric conversion efficiency of 8.07%. The results can provide an efficient support for further applying polyimide thin films to fabricate flexible Sb2S3−ySey thin film solar cells.