Enhanced thermoelectric performance of iso-valent Al substituted Bi2S3via carrier tuning and multiscale phonon scattering

Abstract

Bismuth sulphide is one of the promising thermoelectric material due to its low thermal conductivity, less toxicity, and abundance in nature. This work analyzed an Al-substituted Bi2S3 compounds for mid-temperature thermoelectric applications prepared by hydrothermal route. The combination of stacking faults and point defects significantly improved the phonon scattering, resulting in decreased thermal conductivity in (x = 0.10) Al substituted sample with the value of 0.498 Wm−1K−1 at 623 K. Also, it simultaneously contributes to the enhancement in carrier concentration of −2.15 × 1019 cm−3, resulting the increased electrical conductivity of 10,142 Sm-1 at 563 K. Further, x = 0.025 Al substitution in Bi2-xAlxS3 leads to a high power factor of 338 Wm−1K-2 and a low phonon thermal conductivity of 0.578 μWm−1K−1, leading to a maximum zT of 0.30 at 623 K.