Implication of group 13 elements for the tailoring of Fe3H hydride perovskites for optoelectronic and hydrogen storage applications: An intuition from theoretical study

This study presents a comprehensive analysis of XFe3H compounds (X = B, Al, Ga, In) focusing on their structural, electronic, mechanical, and optical properties for potential applications in hydrogen storage. Structural analysis reveals that these compounds exhibit cubic crystal structures with varying lattice constants, volumes, and densities. Chemical stability is predicted from enthalpy calculation, with GaFe3H revealing a stability slightly better than the rest. The distortion of crystal structures is indicated by the Tolerance factor, BFe3H appeared the most distorted. Mechanical properties such as bulk modulus, elastic constants and shear modulus are assessed, the result being a contrasted mechanical stability across the compounds. AlFe3H demonstrated the highest mechanical stability, whereas InFe3H revealed less stability and a unique behavior. The propensity of our material for hydrogen storage and light-related technology applications is revealed by optical properties, namely, absorption, reflectivity and dielectric functions. BFe3H appeared most suitable for both gravimetric and volumetric storage hydrogen as revealed by our hydrogen storage capacity calculations. Structural changes are exposed by desorption studies, and tolerance factors veered away from ideal crystal structures post-desorption. Insights from phonon dispersion studies, showed that BFe3H, AlFe3H, GaFe3H, and InFe3H exhibited dynamic instability, which may be advantageous for hydrogen desorption. Therefore, this research offers reasonable insights into the mechanical, electronic, structural and optical properties of XFe3H (X = B, Al, Ga, In) compounds, laying the foundation for their possible usage in hydrogen storage.