Abstract
Non-toxicity, ecosystem stability, and distinct performance are the reasons to make halide-based perovskites suitable for solar and thermoelectric purposes. This paper studied elastic properties and structural stability of cubic phase double perovskites (DPs) A(2)NaScI(6) (A = Rb, Cs) by Born stability criteria and tolerance factor. Moreover, we comprehensively examine these DPs in terms of elastic, electronic, optical, and transport behavior. The bandgap range 2.80-2.70 eV is discerned in the electronic band structure and contributes to optoelectronic devices. Most of the absorption is observed in the visible region, and bandgap is reduced by interchanging Rb with Cs atom. The dielectric constants and other optical factors are used to reveal the optical properties of A(2)NaScI(6) (A = Rb, Cs). In the last, the thermoelectric characteristics are calculated by employing BoltzTrap code. The calculated value of the figure of merit (ZT) intimates that the analyzed materials are apposite for thermoelectric purposes.