Engineering Ag2Se thermoelectrics via amorphous nano-Si3N4: a dual-functional strategy for enhanced zT and mechanical strength

Abstract

Ag₂Se-based semiconductors have garnered considerable attention as promising candidates for room-temperature thermoelectric (TE) materials, owing to their excellent electrical properties and remarkably low thermal conductivity. However, their practical application necessitates the simultaneous enhancement of both TE and mechanical properties. In this study, Ag₂Se powder is synthesized via a straightforward microwave-assisted method. An improvement of ∼28.6% in TE performance and an enhancement of ∼15.4% in mechanical properties are achieved by incorporating amorphous nano-Si₃N₄ into Ag₂Se. The electronic and lattice thermal conductivities of Ag₂Se are reduced simultaneously, resulting in a zT of 0.90 at 303 K and an average zT of 0.92 in the temperature range of 303 K to 388 K for the Ag₂Se–0.5 wt% Si₃N₄ sample. These results underscore the potential of Si₃N₄ as an effective nano-inclusion for concurrently boosting the thermoelectric and mechanical properties of Ag₂Se, thereby advancing the development of practical thermoelectric materials. Incorporating amorphous nano-inclusions also shows significant potential for applications in other material systems.