Study on low hydrostatic pressure-dependent optoelectronic, mechanical, and anisotropic properties of heavy thallium perovskites TlPbX3 (X = Cl, Br)

The fundamental physical properties of perovskite materials are crucial for technological applications in a variety of disciplines. Therefore, this study explores the pressure effects on various physical properties of perovskite halides TlPbX3(X = Cl, Br) via density functional theory and investigate the compounds’ optoelectronic performance. The lattice parameters are reduced for enhancing interaction among the constituent atoms upon pressure. The semiconducting nature of both compounds is revealed by band structure and density of states. The band gap is also reduced under pressure, which improves the optical functions. Moreover, the bonding between Tl–Cl(Br) and Pb–Cl(Br) becomes stronger as pressure is applied than that observed at zero pressure systems. All the optical functions become favorable for using both compounds in several interesting optoelectronic applications under pressure. The mechanical properties are also significantly affected by induced pressure. The applied pressure significantly enhances the ductility, machinability, and anisotropic nature of the studied compounds.Graphical abstract