Li+&Ag+ and Li+&Cd2+ double-ion-doping strategy to improve the efficiency of Cu2ZnSn(S,Se)4 solar cells

Ion doping strategy is a promising method to enhance the efficiency of Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells, however, most of the reported works focus on studying the single ion doping in CZTSSe absorber layers . Here, Li + &Ag + and Li + &Cd 2+ double-ion-doping strategy are applied to improve the microstructure and device performances. We found that the double-ion-doping strategy can obviously increase the grain size, reduce the thickness of fine-grain layers and enhance the device performances. Furthermore, the PCEs of Li + &Ag + and Li + &Cd 2+ doped CZTSSe solar cells are up to 8.87% and 8.39%, respectively. It shows an encouraging improvement of over 43.5% and 35.8% enhancement compared with the traditional method (6.18%), and significantly higher than single ion doping strategy (7.60%, 7.99% and 7.11% for Li + , Ag + , and Cd 2+ doped CZTSSe solar cells). This work provides a new solution to improve the microstructure and device performances of CZTSSe solar cells.