Theoretical study of mixed-halide influence on the stability and electronic properties of CsCd(Cl/Br)3

First-principles calculations have been performed to investigate the structural stability, electronic and optical properties of CsCdCl3-xBrx (x = 0, 1, 2, 3) halide perovskites for the first time. The computed lattice constants of these compounds are consistent with the previous theoretical and experimental data. Based on the calculations of formation energies, we find that CsCdCl3 and CsCdCl2Br are highly stable, while CsCdClBr2 and CsCdBr3 are marginally stable. These compounds are dynamically and mechanical stable. All the compounds are indirect band gap semiconductors, and they exhibit large band gaps, which are not suitable for solar cells.