Comprehensive Evaluation to Pb-free RbBaI3 Perovskite for UV detection applications

In the current piece of work, the structural properties, electronic nature, optical response to the radiation, and elastic characteristics of Pb-free perovskite RbBaI3 in perfect cubic structure were calculated using density functional theory calculations. The Perdew-Burke-Ernerhof functional for solid (GGA-PBEsol) and standard Perdew-Burke-Ernerhof functional (GGA-PBE) are used to represent the exchange-correlations term of Kohn-Sham equation to calculate these properties and compare between them. In the findings, there is strong agreement between the values of calculated structure parameters, such as the volume of the primitive unit cell and lattice parameters of the compound, and the results of the previously published works. According to an analysis of the optimization results, the lattice parameters (a=6.81A° and a=6.72A°) for both functionals (PBE and PBEsol) closely match the earlier findings. Furthermore, the formation energy calculations show minimal and negative values, confirming the chemical stability of the compound under study. The indirect band gap along Γ-R symmetry points for this chemical was determined by computing the band structure in GGA-PBE and GGA-PBEsol, which equals 3.22 eV and 3.13, respectively. RbBaI3 is considered a ductile compound based on the analysis of Poisson’s ratio, Cauchy pressure, and Pugh’s ratio. Our findings support that this material is appropriate for UV photodetectors/scintillators.