Structural, elastic, electronic and optical properties of lead-free double perovskites halides Rb2AgYX6 (X F, Cl, Br, I) using DFT functional

Abstract

In recent years, there has been a growing interest in the development of new materials that can serve as alternatives for next-generation energy technologies and replace lead-containing compounds. In this study we conducted thorough evaluation of the structural and mechanical stability of Rb2AgYX6 (X = F, Cl, Br, I) compounds using the Vienna Ab-initio Simulation Package program, applying the generalized gradient approximation potential to evaluate their optoelectronic properties. Our analysis revealed four materials that exhibit exceptional mechanical stability. All the halides were found to be structurally stable in the cubic phase. Elastic stability was further confirmed through the application of the Born stability criteria, based on calculated elastic constants C11, C12, and C44. The band gaps of Rb2AgYF6, Rb2AgYCl6, Rb2AgYBr6 and Rb2AgYI6 were found to be 2.87 eV, 3.6 eV, 3.10 eV and 2.47 eV respectively, and these band gaps are of an indirect nature. The findings indicate that all halogen-based double perovskites materials demonstrate significant potential as photovoltaic absorbers for solar cell applications, as well as in a variety of other applications. Consequently, these perovskite materials emerge as highly promising candidates for prospective applications within the energy sector.