A Thin In2S3 Interfacial Layer for Reducing Defects and Roughness of Cu2ZnSn(S,Se)4 Thin‐Film Solar Cells

Abstract Cu2ZnSn(S,Se)4 (CZTSSe) has generated considerable research interest owing to its composition of abundant elements and excellent light‐absorption properties. However, CZTSSe thin‐film solar cells suffer from a considerable deficit in the open‐circuit voltage (VOC), which is mainly due to the severe interfacial recombination induced by the rough surface of CZTSSe and numerous physical defects. In this study, to improve the morphology and reduce the interfacial recombination, an In2S3 passivation layer was introduced between the CZTSSe and CdS layers via a chemical bath deposition process, and the effects of the In2S3 layer on the device performance were systematically examined by performing various electrodynamic analyses. The CZTSSe solar cells with thin In2S3 layers exhibited impressive increases in VOC and conversion efficiency (from 7.33 to 9.24 %), due to the suppression of …