First principles computation of novel hydrogen-doped CsSrO3 with excellent optoelectronic properties as a potential photocatalyst for water splitting

Abstract

This research exhaustively inquired about the structural, photocatalytic, mechanical, and optoelectronic characteristics of the cubic perovskite CsSrO3−x Hx with the CASTEP code’s implementation of the GGA-PBE formalism. It aims to examine the characteristics of CsSrO3−xHx cubic perovskite with varied concentrations of substituents (x = 0, 0.3, 0.6, 0.9, 1.2, 1.5, 1.8, 2.1, 2.4, 2.7, and 3.0). The stability and synthesizability of the compound are guaranteed by the values of elastic constants and negative formation enthalpies. As H-insertion increases, there are variations in the values of anisotropy and elastic moduli. A semiconductor’s wide bandgap narrows as dopant concentration rises, changing its nature from indirect to direct. The findings imply that the compound’s electronic characteristics can be altered through the application of dopants, rendering them appropriate for a range of optoelectronic uses. The inclusion of hydrogen caused the structural change from cubic to tetragonal and orthorhombic. The distortion caused the lattice parameters to vary in values. Tolerance factor lies in range of 0.7–1 that ensures structural stability of CsSrO3−x Hx. Our computed results reveal the anisotropic nature of our compound. The obtained bandgap for CsSrO3−xHx indicates that both O2 evolution and H2 reduction are allowed since the requisite redox potentials are satisfied. Photocatalytic properties of CsSrO2.4H0.6 reveals that it is the best doped system as a potential candidate for water-splitting photocatalysis, as it has equal effectiveness to both oxidation and reduction processes. The bandgap was shown to decrease from 5.33 eV to 2.812 eV at complete hydrogen insertion, which also had an impact on the material’s optoelectronic characteristics. All the optical considerations such as dielectric functions, refractive indices, extinction coefficients, optical reflectivity, absorption coefficients, and loss functions are also thoroughly explained. The material exhibits mechanical stability along with ionic and covalent bonding.