First-principles investigation of structural, electronic, optical, and elastic properties of TlPtF3 fluoroperovskite for optoelectronic applications

This study presents a comprehensive investigation of the structural, mechanical, electronic, and optical properties of the TlPtF 3 compound, a thallium-based halide perovskite. Using density functional theory (DFT) within the CASTEP code, and considering both GGA and GGA+ U approximations, we confirm the structural stability of TlPtF 3 through geometric optimization based on the Birch-Murnaghan equation of state. Mechanically, the compound exhibits ductility, scratch resistance, and anisotropy, indicating robust stability. Band structure calculations reveal a semiconducting behavior with an indirect bandgap of 0.556 eV (GGA) and 1.102 eV (GGA+ U ). Analysis of total and partial density of states clarifies the contributions of electronic states to the band structure and the origin of the bandgap. Optical properties, examined in the 0–20 eV range, show strong absorption and high optical conductivity at high energies while remaining transparent at low energies. TlPtF 3 remains stable from 0 to 1000 K, with GGA providing a reliable description of its behavior. These findings highlight TlPtF 3 as a promising candidate for ultraviolet optoelectronic applications.