Ag, Ti dual-cation substitution in Cu 2 ZnSn(S,Se) 4 induced growth promotion and defect suppression for high-efficiency solar cells

A dual-cation-substituted Cu 2 ZnSn(S,Se) 4 involving Ag and Ti to separately occupy partial Cu and Sn is developed. Such a new strategy can simultaneously promote crystal growth and suppress detrimental defects, leading to a high efficiency of 12.73%.