Enhancement of Open-Circuit Voltage of Solution-Processed Cu₂ZnSnS₄ Solar Cells with 7.2% Efficiency by Incorporation of Silver

High Resolution Image Download MS PowerPoint Slide Recently, considerable attention in the development of Cu 2 ZnSnS 4 (CZTS)-based thin-film solar cells has been given to the reduction of antisite defects via cation substitution. In this Letter, we report the substitution of copper atoms by silver, incorporated into the crystal lattice through a solution processable method. We observe an increase in open-circuit voltage ( V OC ) by 50 mV and an accompanying rise in device efficiency from 4.9% to 7.2%. The incorporation of Ag is found to improve the grain size, enhance the depletion width of the pn-junction, and reduce the concentration of antisite defect states. This work demonstrates the promising role of Ag in reducing the V OC deficit of Cu-kesterite thin-film solar cells.