Efficient flexible Mo foil-based Cu2ZnSn(S, Se)4 solar cells from In-doping technique.

Cation substitution has an important impact on the power conversion efficiency (PCE) of Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells. Herein, a significant PCE enhancement of flexible indium-doped CZTSSe solar cells has been achieved by partially substituting Sn4+ with In3+. Systematic measurements indicate that In doping in CZTSSe film effectively improves the crystallinity and carrier concentration of the absorber layer. Meanwhile, the treatment reduces interface recombination and band tailing by passivating deep defects and increases the open-circuit voltage (V oc) of the solar cells. By physical analysis, the key parameters for the solar cell diode such as A , J 0 , R s and R sh are significantly improved after In-doping, indicating better PN junction quality. Under the optimal In-doping (x = In/(Sn + In) = 9%), the flexible Cu 2 ZnSn 1- x In x (S,Se) 4 solar cell has been successfully obtained with the best efficiency of 7.19% and the V oc enhancement of 62 mV due to reduced V oc deficit and band tailing. • Flexible CZTISSe solar cells with efficiency of 7.19% are obtained via In doping. • Doping In can improve the V oc and carrier transportation of the solar cells. • Effects of In doping on CZTISSe films and solar cells have been systematically studied. [ABSTRACT FROM AUTHOR]