DFT study of electronic, optical, and elastic properties of double perovskites Rb2YAgX6 (X= Br, I) compounds for opto-electronic device applications


 Density functional theory calculations have been used to investigate the electrical, optical, and elastic characteristics of double perovskites Rb2YAgX6 (X= Br, I) halides for exploring their opto-electronic applications. For optimizing the lattice constants and structure parameters, we have fitted the Murnaghan equation of state to the total energies computed for a wide range of lattice volumes. For the ground state lattice constants, the computed electronic band structure diagrams show indirect wide band gaps of 4.2 eV and 3.2 eV for Rb2YAgBr6 and Rb2YAgI6, respectively. Our results indicate that both of the studied halides absorb electromagnetic radiations beyond the visible region and are therefore appear potential candidates for optoelectronic applications in the ultraviolet rage of spectrum. The mechanical stability and ductility of the two halides are examined in terms of the elastic constants. Our results clearly demonstrate that the device application potential of these double perovskite halides is interesting owing to their high mechanical stability and hardness.