Predicting the electronic, optical, and thermometric properties of novel K2LiSbX6 (X = Cl, Br, I) semiconductors: A first-principles study

Abstract

Due to their acceptable optical absorption efficiency, greater stability, adjustable bandgap, huge carrier mobility, non-toxicity, readily accessible raw materials, and low cost. The halide-based double perovskites (DPs) have demonstrated several advantages over halide-based perovskites. The Perdew-Burke-Ernzerhof (PBE) functional is used to compute the electrical, optical, mechanical, and thermal properties of halide-based DPs K2LiSbX6 (X = Cl, Br, I) in the Generalized Gradient approximation (GGA) framework of density functional theory (DFT). The objective of studying these materials is to compute the electronic, optical, and thermal properties, to use these materials in the solar cell and thermal applications. It is calculated what the structural parameters are, including the lattice parameter, cell volume, total energy, bulk modulus, pressure derivative, and tolerance factor. The compound’s semiconducting nature is revealed by the electrical density of states, and the band structure shows that the band gaps (3.7 eV, 2.9 eV, and 2.2 eV) are indirect in nature. To address the under-estimated band gap as found in the GGA-PBE functional, the mBJ functional is introduced. Electronic structures analysis and provide explanations for the actual and fictitious parts of the dielectric function ε (ω), absorption coefficient α(ω), energy loss function L(ω), reflectivity ℜ(ω), refractive index n (ω), and extinction coefficient K (ω) versus photon energy (eV). According to these criteria, Br, Cl, I-based materials are optically preferable to K-based compounds. Because of the above predicted outcomes, we conclude that these materials are good candidates for optoelectronics and thermal devices.