How the Copper Dopant Alters the Geometric and Photoelectronic Properties of the Lead‐Free Cs<sub>2</sub>AgSbCl<sub>6</sub> Double Perovskite
Gan Yu, Shaoming Xue, Ruotong Yin, Qiaoqian Wu, Tianhao Gao, Yixian Song, Ruijie Wang, Wei‐Yan Cong, ChengBo Guan, Ying‐Bo Lu
Abstract
Abstract The Cu‐modulated lead‐free double perovskite Cs 2 AgSbCl 6 shows excellent photoelectric performances. Thus the distribution of Cu dopants inside Cs 2 AgSbCl 6 and the influence induced by them are investigated thoroughly. The variation of charge distribution and then the electronic environment around the Cu dopant are simulated, which support the preferred formation of Cu Ag defect in Cs 2 AgSbCl 6 with a nominal monovalent state. Compared with other Cu‐related defects, this configuration introduces the weakest tensile stress around the defects and the slightest distortion of the metal octahedron. Owing to the special Cu Ag defect, the electronic structures of Cs 2 AgSbCl 6 system change, e.g., the bandgap reduces manifestly, ascribing to the predominant contribution from Cu‐3d orbitals to the band edges. With the increase of concentration of Cu dopants, the bandgap of Cs 2 AgSbCl 6 decreases further in a monotonic but gentle way, originating from the extra interactions between the Cu‐3d orbitals. Therefore, the critical insight to understand the photoelectronic properties of Cs 2 AgSbCl 6 modulated by the Cu dopants is provided.