Theoretical investigation of structural, electronic, and optical properties of halide cubic perovskite CsPbBr3-xIx

Abstract

The influence of the substitution of bromine (Br) with iodine (I) on electronic structure and optical characteristics of cubic perovskite CsPbBr3-xIx (x = 0.00, 0.12, 0.24, 0.33, 0.48, 1, 2 and 3) was investigated by the method of the full potential linearized augmented plane wave (FP-LAPW). This method was used within the framework of density functional theory as implemented in the wien2k code. In this work, Perdew-Burke-Ernzerhof generalized gradient approximation (PBE-GGA) was used for the treatment of exchange-correlation effects in calculations. The PBE-GGA and the modified Becke-Johnson potential combined to the GGA approximation (mBJ-GGA) were used for the calculations of electronic band structures and optical properties. The obtained results indicated that the lattice parameters of the studied compound increase as the substitution by iodine increases in the compound. These results are found to be in good agreement with those previously reported in literature. The effect of lattice constant on the bandgap has also been investigated. Moreover, the study of the electronic and optical properties of this halide perovskite CsPbBr3-xIx including the density of states, band structure, dielectric function, absorption coefficient was done. It was found that these compounds exhibit properties of semiconducting materials with a direct bandgap value ranging from 1.36 to 1.44 eV and absorption coefficients higher than 104 cm−1. These results clearly show that the CsPbBr3-xIx compounds can be used as promising candidates for solar cell and optoelectronic applications.