Regulation of Zn/Sn ratio in kesterite absorbers to boost 10% efficiency of Cu2ZnSn(S, Se)4 solar cells |
(color online) (a) Tauc plots calculated from ultraviolet–visible transmission and measurements for R0–R4 CZTSSe absorber films. (b) Normalized PL spectra for R0–R4 CZTSSe absorber films. |