The effect of sodium on antimony selenide thin film solar cells

Abstract

Sodium (Na) has been identified as a benign contaminant in some thin film solar cells. Here, we have studied the impact of sodium on the properties of CdS/Sb₂Se₃ superstrate thin film solar cells. NaF deposited at the CdS/Sb₂Se₃ heterojunction severely degraded the device performance, yet NaF introduced into the Sb₂Se₃ film after the completion of the heterojunction showed a negligible influence on the film conductivity and device performance. We concluded that sodium could easily diffuse into the Sb₂Se₃ film and probably locates in the gap between (Sb₄Se₆)_n ribbons, being inert in Sb₂Se₃ solar cells.