Microstructure and thermoelectric performance of Bi0.5Sb1.5Te3 rapidly prepared via solid-state reaction
摘要
Sb2Te3-based materials are recognized as outstanding p-type thermoelectric candidates near room temperature; nevertheless, their preparation strategies and thermoelectric performance still warrant further optimization. In this work, single-phase Bi0.5Sb1.5Te3 bulk thermoelectric materials were successfully synthesized via a solid-state reaction method under controlled conditions of 673–923 K, holding times of 8–60 min, and heating rates of 5–20 K min−1. XRD analysis confirmed a rhombohedral-layered structure, while SEM and TEM observations revealed a porous lamellar microstructure accompanied by dislocations. Such structural features are beneficial for enhancing phonon scattering, thereby reducing the lattice thermal conductivity. Electrical transport measurements at room temperature showed that increasing the preparation temperature led to a reduction in resistivity, reaching as low as 1.11 mΩ cm at 923 K. Furthermore, variable temperature measurements (300–523 K) demonstrated that the sample prepared at 873 K achieved the lowest lattice thermal conductivity of 0.45 W m−1 K−1 at 323 K and a maximum power factor of 25 μW cm−1 K−2, resulting in an optimal dimensionless figure of merit of zT ~ 0.96.