Tailoring the Lattice Thermal Conductivity of Al-Incorporated Ag2Se for Near Room Temperature Waste Heat Recovery

Ag₂Se is categorized as a typical ′phonon-liquid-electron-crystal (PLEC)′material, exhibiting an extremely low $$ . In this study, Al substituted Ag₂Se samples were synthesized by mechanical alloying process followed by hot press densification technique. The Al substituted sample shows an exceptionally high mobility of 2360 cm² V⁻¹ S⁻¹ at room temperature and a maximum power factor of 1442 μWm⁻¹ K⁻² at 383 K. The phonon scattering induced by various crystal imperfections due to Al substitution helped to obtain a very low lattice thermal conductivity $$ value of 0.3 W/mK. A high figure of merit (zT) of 0.4 at 383 K was obtained as a result of the simultaneous effect of boosting the electrical transport properties and decreasing the thermal conductivity. This present work summarizes that the Al substitution is highly significant in improving the thermoelectric properties of Ag₂Se.