Theoretical study of Ca-doped CsPbBr3 and CsPbCl3 with enhanced structure stability and excellent optoelectronic properties

Doping is an effective strategy to enhance the stability and performance of perovskite optoelectronic device. However, it is necessary to further investigate the possibility of Ca metal element doping into perovskite lattices and the doping effect on perovskite. In this study, density functional theory (DFT) calculations are performed to study the doping formation energies, structural and optoelectronic properties of Ca-doped CsPbBr3 and CsPbCl3. The results suggest that Ca can be doped into Br/Cl-based perovskites under Pb-poor conditions, enhancing the interaction between Ca and halide atoms, increasing the band gap and enlarging the exciton binding energy. Meanwhile, optical absorption has been decreased after Ca-element doping in the perovskite lattices, and still remained at a level of 105 cm-1. This work explores the intrinsic doping mechanism of Ca metal elements in Br/ Cl-based perovskites, proposing that Ca is a suitable doping element to improve the stability and optoelectronic performance of perovskite.