Comparative study of mechanical, electronic, and optoelectronic properties of all inorganic CsPbX₃ (X = Cl, Br, I) perovskite by DFT approach

The organic and inorganic hybrid Pb-halide perovskites with formula ABX₃ (A is a monovalent organic cation, B is a lead cation and X is a halide anion) have emerged as a revolutionary semiconductor in various applications. But the long-term stability and Pb toxicity of these perovskites attract more and more attention, therefore, all inorganic perovskites became an alternative perovskite for optoelectronic applications. To this point of view, in this research work, we theoretically study the mechanical, electronic and optoelectronic properties of CsPbX₃ (X = Cl, Br, I) perovskites for potential optoelectronic and solar cell applications. The first principles calculations were performed based on the density functional theory (DFT) in the framework of generalized gradient approximation (GGA) in CASTEP code software. The electronic properties calculation shows that CsPbI₃, CsPbBr₃ and CsPbCl₃ direct band gap nature with the band gap lying between 1.47 eV and 2.20 eV. The lattice parameters and volume strongly depend on the halide components. The mechanical stability is higher for Cl-based halides than the rest halides. It is also seen that the optical properties such as reflectivity, dielectric constants, refractive index, optical conductivity and absorption coefficient can be tuned by varying the halide component which may pave the way to develop optoelectronic and advanced electronic devices.