Abstract
In this work, electronic, structural, optical, thermoelectric and elastic characteristics of K2NaXBr6(X = Sc, Y) are studied by applying first principles method. The analysis of band structure (BS) and density of states (DOS) revealed the direct wide band gap (Eg) at Г symmetry points. The Eg value is 3.72 eV for K2NaScBr6 and 5.04 eV for K2NaYBr6. The tolerance factor (τ) for K2NaScBr6 and K2NaYBr6 are 0.9 and 1.0, correspondingly which confirm the cubic nature of mentioned compounds. Both compounds show negative values of formation energies which confirm their stable structure. The absorption of optical factors lies in ultra-violet (UV) region which make them suitable for photovoltaic devices. The elastic features verify ductility, anisotropy, and mechanical stability of K2NaXBr6(X = Sc, Y). The thermal conductivity (k/τ), see-beck coefficient (S), figure of merits (ZT) and electrical conductivity (σ/τ) are also calculated using Boltz-Trap code. Thermoelectric and optical characteristics showed that investigated perovskites are suitable for renewable energy applications.
•Results revealed the Eg 3.72 eV and 5.04 eV for K2NaScBr6 and K2NaYBr6, respectively.•The tolerance factor (τ) for K2NaScBr6 and K2NaYBr6 are 0.9 and 1.0, correspondingly.•Elastic features verify ductility, anisotropy, and mechanical stability of K2NaXBr6(X = Sc, Y).•Results revealed that investigated compounds are suitable for renewable energy applications.