Modulation of electronic and optical properties in mixed halide perovskites CsPbCl_(3x)Br_(3(1-x)) CsPbBr_(3x)I_(3(1-x))

摘要

The recent discovery of lead halide perovskites with band gaps in the visible presents important potential in the design of high efficient solar cells. CsPbCl_3, CsPbBr_3 and CsPbI_3 are stable compounds within this new family of semiconductors. By performing the first-principles calculation, we explore the structural, electronic and optical properties of CsPbCl_(3x)Br_(3(1-x)) and CsPbBr_(3x)I_(3(1_x)) with various compositions of halide atoms. Structural stability is demonstrated with halide atoms distributing randomly at the halide atomic sites. CsPbCI_(3x)Br_(3(1_x)) and CsPbBr_(3x)I_(3(1-x)), exhibit the modulation of their band gaps by varying the halide composition. Our results also indicate that CsPbCI_(3x)Br_(3(1-x)) and CsPbBr_(3x)I_(3(1_x)) with different halide compositions are suitable to application to solar cells for the general features are well preserved. Good absorption to lights of different wavelengths has been obtained in these mixed halide perovskites.