DFT study of elastic, structural, and optical properties of K2InAgZ6 (Z = Cl, Br, I) perovskites: potential for optoelectronic applications

In this article, a comprehensive research was carried out to investigate the elastic, structural, and optoelectronic properties of double perovskite compounds K₂InAgCl₆, K₂InAgBr₆, and K₂InAgI₆ by using density functional theory. Goldsmith’s tolerance factor (t_G), whose values are near to unity, was used to assess the structural stability of the cubic perovskite structure. According to the analysis of electronic characteristic, K₂InAgCl₆, K₂InAgBr₆, and K₂InAgI₆ are semiconductors with a tiny band gap, calculated using the mBJ-PBE sol potential with band gap values of 2.48 eV, 1.47 eV, and 0.23 eV, respectively. A comprehensive analysis of the optical characteristics of these compounds was conducted across an energy range from 0 to 10 eV. The results revealed that K₂InAgCl₆, K₂InAgBr₆, and K₂InAgI₆ exhibit significant conductivity and absorbance properties in wide energy ranges, which is confirmed by density of states analysis. Moreover, the optical characteristics shows that lower photon energy relates to high optical transmission, while higher energies result in more optical absorption of material. These results demonstrate that K₂InAgCl₆, K₂InAgBr₆, and K₂InAgI₆ are viable material candidates for use in high-frequency UV optical devices.