Low-Temperature, Solution-Based, Scalable Synthesis of Sb2Te3 Nanoparticles with an Enhanced Power Factor

Nanostructured thermoelectric (TE) materials, for example Sb2Te3, PbTe, and SiGe-based semiconductors, have excellent thermoelectric transport properties and are promising candidates for next-generation TE commercial application. However, it is a challenge to synthesize the corresponding pure nanocrystals with controlled size by low-temperature wet-chemical reaction. Herein, we report an alternative versatile solution-based method for synthesis of plate-like Sb2Te3 nanoparticles in a flask using SbCl3 and Te powders as raw materials, EDTA-Na2 as complexing agent, and NaBH4 as reducing agent in the solvent (distilled water). To investigate their thermoelectric transport properties, the obtained powders were cold compacted into cuboid prisms then annealed under a protective N2 atmosphere. The results showed that both the electrical conductivity (σ) and the power factor (S2σ) can be enhanced by improving the purity of the products and by increasing the annealing temperature. The highest power factor was 2.04 μW cm−1 K−2 at 140°C and electrical conductivity remained in the range 5–10 × 103 S m−1. This work provides a simple and economic approach to preparation of large quantities of nanostructured Sb2Te3 with excellent TE performance, making it a fascinating candidate for commercialization of cooling devices.