Pressure induced variations in the band structure, optical and mechanical properties of lead free double halides perovskites K2CuAsX6 (X = Cl, Br): A first-principles calculations

• Published in: Inorganic chemistry communications Vol. 156; p. 111262
• Main Authors: Shafiq, Maleeha, Shah, M. Qasim, Murtaza, G., Raza, Hafiz Hamid, Ramay, S.M., Irfan, M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2023
• Subjects: Elastic properties; Halide Double Perovskite; Optical properties; Pressure-induced; Semiconductor to metal transition; Semiconductor to metal transition; Pressure-induced; Halide Double Perovskite; Elastic properties; Optical properties
• ISSN: 1387-7003; 1879-0259
• DOI: 10.1016/j.inoche.2023.111262

The decrease in lattice parameter of K2CuAsCl6 and K2CuAsBr6 under 0 GPa to 80 GPa pressure. [Display omitted] •First principles investigation of K2CuAsX6X=Cl,Br compounds.•DFT calculations were used to investigate the structural, electronic, optical, and elastic properties under pressure.•The highest optical conductivity with energy loss and strongest absorption are observed in K2CuAsBr6,•It also has the best photovoltaic activity. This article is focused on studying the response of halide double perovskite materials under pressure using the WIEN2k code by applying the Full Potential- Linearized Augmented Plan Wave (FP-LAPW) method under the framework of Density Functional Theory (DFT). Both compounds show structural stability, based on ground state energy, tolerance factor, and formation energy and have a perfectly cubic structure with the Fm-3 m space group. Lattice parameters decrease as pressure is applied, which causes a reduction in the indirect band gap of both materials by applying Perdew –Burke – Ernzehof –Generalised Gradient Approximation (PBE-GGA). The decrease in the band gap under pressure changes the semiconducting order of the material to metallic. Metallic behaviour observed at 60 GPa and 20 GPa for K2CuAsCl6 and K2CuAsBr6, respectively. The optical response in the visible regions confirms the studied materials are good candidates for solar cell application. Optical absorbance of K2CuAsBr6 is observed higher than other material and it increases as pressure rise to 80 GPa. Low energy loss is observed for the region in which absorbance is high. The mechanical stability of both materials is also supported by their elastic properties, as their bulk and shear moduli rise with increasing pressure.