Tailoring the optoelectronic, photo-catalytic, thermoelectric and thermodynamic properties of halides Li2InBiX6 (X=Cl, Br, I) for energy conversion—DFT study

Abstract Double perovskite halides are identified as promising materials for diverse applications specifically as renewable energy sources (solar cell devices) and thereby addressing the global energy shortage. This study aims to assess the physical (electronic, optical, dielectric, and thermoelectric) properties of Li 2 InBiX 6 (X = Cl, Br, I) halides by means of density functional approach. Owing to the materials’ minimal formation energy, the structures demonstrate stability in the cubic phase. The analyzed double perovskite halides display a semiconducting nature, characterized by a direct bandgap, i.e., Li 2 InBiCl 6 (Eg = 1.7 eV), Li 2 InBiBr 6 (Eg = 1.3 eV), and Li 2 InAuI 6 (Eg = 1.1 eV). Moreover, complex dielectric functions are examined to better understand the optical characteristics of the analyzed halides. These halides are well-suited for optoelectronic applications, as evidenced by the estimated optical parameters that indicate maximum light absorption in IR and visible spectrums. The study extends for analyzing ZT value, Seebeck factor, and electronic conductance within the temperature range 30–800 K. The relatively small band gap suggests enhanced suitability for thermoelectric applications, as evidenced by a higher power factor. The photo-catalytic study revealed that Li 2 InBiX 6 are good candidates for the oxidization of H 2 O at pH values 0–7. Based on the anticipated thermoelectric and optical characteristics, the studied double perovskite halides emerge as potential candidates for energy conversion systems.