Work

First-principles investigation of structural, electronic, optical, and thermoelectric properties of Li2X (X = Te, Se, S) chalcogenides for energy and optoelectronic applications

Year: 2025

Type: article

Abstract: The structural, electronic, optical, elastic, and thermoelectric properties of Li 2 X (X = S, Se, Te) chalcogenides were systematically investigated using density functional theory. Volume-energy analysis via Birch-Murnaghan fitting reveals that Li 2 S exhibits the greatest structural stability. The bandgaps decrease from Li 2 S (∼3.2 eV) to Li 2 Se (∼1.8 eV) and Li 2 Te (∼1.0 eV), correlating with lattice constants and chalcogen mass. Li 2 Te’s narrow direct bandgap and strong hybridization suggest thermoelectric potential, while Li 2 Se is promising for optoelectronics. Li 2 S, with a wide bandgap and high ionic conductivity, is ideal for optical and solid-state electrolyte applications. Elastic analysis shows Li 2 Se is the stiffest and most ductile, while Li 2 Te and Li 2 S show greater anisotropy. Optical results confirm that heavier chalcogens enhance reflectivity and metallicity, whereas lighter ones promote insulating behavior. These findings demonstrate the tunability of Li 2 X compounds for diverse energy and electronic applications.

Source: Results in Physics

DOI: 10.1016/j.rinp.2025.108334