Exploring the Structural, Electronic, and Optical Characteristics of ZrSnO 3 Through First‐Principles Calculations for Optoelectronics and Photocatalytic Applications

ABSTRACT We performed first‐principles density functional theory calculations to methodically analyse the structural, mechanical, electronic, thermal, and optical properties of trigonal ZrSnO 3 under external pressure up to 60 GPa with GGA‐PBE and HSE06 functionals. The optimised structure retains its crystallographic phase along the entire pressure range and meets Born mechanical stability criteria. The calculated phonon spectra confirm the dynamical stability of ZrSnO 3 in the 0–10 GPa pressure range, where no imaginary frequencies are observed. With increasing pressure, slight imaginary modes appear at 20 and 40 GPa, while clear imaginary frequencies are detected at 60 GPa, indicating the emergence of dynamical instability at higher pressures. Although the Born criterion and elastic constant confirm the mechanical stability of ZrSnO 3 up to 60 GPa. Lattice parameter and unit‐cell volume continuously reduce as pressure increases, showing lattice contraction and interatomic bonds becoming stronger. Electronic band‐structure calculation has shown that ZrSnO 3 is an indirect band‐gap semiconductor, and its energy gap shrinks from 2.57 to 1.13 eV in the HSE06 method, which is an obvious indication of pressure tuning. DOS and PDOS elucidate that oxygen 2p states govern the valence band, while zirconium 4d states mainly contribute to the conduction band, in addition to the tin minor states. Optical characteristics exhibit strong absorption in the visible and UV region, increased optical conductivity, and a large dielectric constant. Due to structural stability, non‐toxicity, and tuning of its electronic properties, ZrSnO 3 is considered a highly potential material for photocatalytic processes, UV photodetectors, and pressure‐sensitive optoelectronic devices. The material possesses promising band edge potentials, which are favourable in dye degradation and hydrogen generation through water splitting.