Investigation of Structural, Electronic, Optical, and Elastic Properties of Ru-Based Inorganic Halide Perovskites ARuBr3 (A = K, Rb, Cs) via DFT Computations

We are prompted to examine KRuBr3, RbRuBr3, and CsRuBr3 materials since they are novel and superior semiconductor materials for sustainable energy devices. In this investigation, we adopted approaches based on density functional theory to conduct an extensive computational study of these materials and clarify their diverse features. We implemented the Birch-Murnaghan fit to figure out the structural stability of these materials under scrutiny, and the modified potential of Becke-Johnson has been employed to establish their electronic properties. The KRuBr3, RbRuBr3, and CsRuBr3 materials' band-structure data during the evaluation rendered it obvious that these materials exhibit an indirect semiconductor nature, with bandgap values of 1.81 eV, 1.79 eV, and 1.74 eV, respectively. The three critical elastic constants for each of these materials under inquiry were initially determined and these values were subsequently employed to assess every mechanical characteristic of the materials under study. To identify the degree of ductility, the computed Pugh's and Poisson's ratios for the KRuBr3, RbRuBr3, and CsRuBr3 materials were confirmed. The bandgap values of the explored materials lie in the range of the visible spectrum reflecting its feasibility for solar cell technology. Also, the highest peaks of absorption coefficient and lowest value of energy loss and reflectivity suggest its importance in photovoltaic applications.