Electronic, optoelectronic, and transport properties of <scp> Li ₂ ScCuX ₆ </scp> (X= Cl, Br, and I) double perovskites: <scp>DFT</scp> study for nano‐architectonics devices

Abstract Devices employing double perovskite semiconductors have gained attention due to their favorable properties, including a compositionally and chemically stable crystal structure. This study utilizes density functional theory (DFT) and employs the full‐potential linearized augmented plane‐wave (FP‐LAPW) approach to examine the electrical, structural, thermoelectric, optical, and mechanical characteristics of Li 2 ScCuX 6 (X = Cl, Br, and I) double perovskite halides. The research focuses on evaluating optoelectronic and thermoelectric device characteristics. The stability of the anticipated compounds in cubic phase was validated using the octahedral factor and Goldsmith tolerance factor. Furthermore, to validate their thermodynamic and dynamic stabilities, we evaluated the formation energy and AIMD simulation technique. TB‐mBJ potential was utilized to calculate the electronic, optoelectronic, and thermoelectric characteristics. The analysis of the electronic band structure indicates an indirect band structure semiconducting characteristic, with band gap values of 1.71 eV for Li 2 ScCuCl 6 , 1.70 eV for Li 2 ScCuCl 6 , and 1.62 eV for Li 2 ScCuCl 6 . The optical characteristics present low reflectivity and elevated light absorption coefficients (10 4 /cm 2 ) within the visible spectrum. Their spectral response spans the ultraviolet to visible range, rendering them suitable for usage in solar cells and optoelectronic devices. The mechanical stability is validated by the Born–Huang stability criteria. The ductility of all analyzed perovskites is confirmed by Pugh's ratio, Cauchy pressure, and Poisson's ratio. BoltzTraP code was utilized to calculate the Seebeck coefficient, thermal conductivity, and electrical conductivity. The results demonstrate that Li 2 ScCuCl 6 , Li 2 ScCuBr 6 , and Li 2 ScCuI 6 exhibit a significant figure of merit ranging from 0.39 to 0.49. The results suggest that the investigated double perovskite Li 2 ScCuCl 6 is a promising candidate for photovoltaic, optoelectronic, and thermoelectric applications.