First principle insights on optoelectronic, mechanical, and thermoelectric properties of double perovskites Li₂ScAu (Br/I)6 for energy harvesting applications

Abstract

Li-based double perovskites (DPs) are extensively studied due to their potential applications for solar cells and thermoelectric devices. In the current paper, we explored the electronic, optical, transport, and mechanical aspects of Li2ScAu (Br/I)6 by density functional theory (DFT) based calculations. The tolerance factor and Born Criteria have been assumed for structural and mechanical stability. In contrast, energy and phonons band structures are examined for thermodynamic and dynamic (Lattice vibration) stability formation. The band gaps 1.96 eV and 1.42 eV for Li2ScAuBr6 and Li2ScAuI6 fall the absorption bands in the visible zone. The optical behavior in the energy range 0-5.0 eV has been addressed. Furthermore, low lattice thermal conductivity, large Seebeck coefficient, and electrical conductivity enhance the figure of merit (ZT) scale, increasing their importance for thermoelectric generators.