First principle study of the optoelectronic, and thermoelectric properties of novel direct band gap ternary chalcogenides

Due to their distinctive crystal structures and the interaction of their constituent elements, ternary chalcogenides, have tunable electronic, optical, and thermoelectric properties. In this work, we employ first-principles calculations to investigate the structural, electronic, optical, and thermoelectric properties of novel Ga₂TeM₂ (M = S, Se) materials. Based on our results, both materials have visible-range direct band gaps, which enables them to be applied in optoelectronic and photovoltaic systems. Their structural stability and synthesizability are confirmed by the calculated cohesive and formation energies. High absorption coefficients and strong photon-matter interactions are shown by in-depth optical investigations, underscoring their potential for solar energy harvesting. Promising thermoelectric figures of merit values are also obtained via thermoelectric performance evaluation, which shows favorable Seebeck coefficients, high electrical conductivity, and low thermal conductivity. The electronic band structure and thermoelectric efficiency are affected when sulfur is substituted with selenium, offering adaptability for certain applications. This comprehensive study highlights that both materials as flexible with significant potential in clean energy technologies such as thermoelectrics and photovoltaics. Our investigation bridges the gap between theoretical predictions and real-world implementations in green energy solutions by offering insightful information on the design and development of these high-performance energy harvesting materials.