First principle investigation of structural, electronic, optical and thermoelectric properties of Chalcogenide Sr2GeX4(X=S, Se)

The electronic and optical properties of ternary-type chalcogenides are of great interest for solar energy conversion applications. In this study, we investigated the optical, electronic, and transport properties of Sr2GeX4 (X = S and Se) materials using first-principles calculations based on density functional theory. We found that these materials have a robust covalent bond nature and substantial band gaps. The density of states calculations revealed that the Sr -s and Ge -s states play a predominant role, while the S -s and S -p states have a minor influence. The optical properties of the materials are anisotropic, and they have significant UV absorption. The positive Seebeck coefficient values suggest that holes are the primary charge carriers in both materials. The study also discussed various other crucial thermoelectric parameters, which collectively suggest the suitability of these materials for thermoelectric applications. Overall, this study provides valuable insights into the optoelectronic and thermoelectric properties of Sr2GeX4 materials, which could significantly contribute to the development of efficient optoelectronic devices.