Optimised structural, electronic, optical and mechanical properties of SrTiO3-xHx for photovoltaic applications: a DFT insight

Abstract

Density Functional Theory (DFT) computations, by CASTEP code with GGA-PBE correlation functional, for SrTiO3-xHx have been carried out to compute elastic, mechanical, structural, electronic, and optical characteristics of SrTiO3-xHx perovskite hydride material at varied levels of replacements (x = 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, and 3.0). With the doping of hydrogen, the structure changed from cubic to orthorhombic and then tetragonal. Elastic parameters and negative value of formation energies demonstrate the durability and formability of these materials. It is established that these compounds are brittle by examining the B/G ratio and Poisson ratio. A bandgap is increased from 1.791 eV to 2.441 eV as dopant concentration rises, changing the semiconductor's nature from indirect to direct. Additionally, a detailed explanation of the optical properties for photons in the energy spectrum of 0–10 eV was provided dielectric functions, refractive indices, extinction coefficients, and 0–50 eV were provided including reflectance, absorbance, and energy loss. By increasing hydrogen doping, the highest absorption peak in the visible region is observed for x = 2.1, which shows that SrTiO3-xHx perovskite hydride has revealed stronger potential for photovoltaic applications.