Precisely tuning Ge substitution for efficient solution-processed Cu2ZnSn(S, Se)4 solar cells
Wang Xinshou, Kou Dongxing †, Zhou Wenhui, Zhou Zhengji, Tian Qingwen, Meng Yuena, Wu Sixin ‡
       

(color online) (a) XRD patterns and (b) enlarged (112) crystal face of CZTGSSe films with different Ge content.