Influence of silver incorporation on CZTSSe solar cells grown by spray pyrolysis

Enhanced crystallinity and grain growth were observed for Ag containing as-prepared layers as well as selenized layers. As a potential consequence, this enhanced grain growth appears to facilitate the formation of MoSe2 layer at the back contact/absorber interface during the selenization process. Further, the incorporation of Ag improved the performance of kesterite devices up to 7.1% for 5% Ag/(Cu+Ag) composition. However, for Ag contents beyond this level we observed impairing of the device efficiencies with higher Ag content.