Optimization method and performance study of Bi2Te3 nanosheets preparation based on solvothermal method

$\text{Bi}_{2}\text{Te}_{3}$, as the thermoelectric material with the most superior thermoelectric properties in the low and medium temperature regions, is now widely used in various thermoelectric devices. Despite the great progress made in recent years, the preparation of high thermoelectric performance $\text{Bi}_{2}\text{Te}_{3}$ nanomaterials by a facile and environmentally friendly method is still challenging. In this paper, an efficient, rapid and environmentally friendly method for the synthesis of $\text{Bi}_{2}\text{Te}_{3}$ nanosheet materials was explored based on the solvothermal method. The $\text{Bi}_{2}\text{Te}_{3}$ nanomaterials with good thermoelectric properties were synthesized by modulating the morphology of Bi $_{2}\text{Te}_{3}$ nanomaterials by changing the experimental conditions. Single-crystal hexagonal $\text{Bi}_{2}\text{Te}_{3}$ nanosheets with regular morphology, uniform size and good monodispersity were prepared by using $(\text{CH}_{2}\text{OH})_{2}$ as the reaction solvent and weak reducing agent. A large number of nanocrystalline boundaries existed in the sintered samples, and the nanocrystalline boundaries could increase the phonon scattering and decrease the thermal conductivity. The results of the findings show that the $\text{Bi}_{2}\text{Te}_{3}$ nanomaterials prepared in this paper have good thermoelectric properties with a thermoelectric figure of merit 14% higher than that of commercial $\text{Bi}_{2}\text{Te}_{3}$. This work provides an efficient and rapid method for the preparation of Bi $_{2}\text{Te}_{3}$ nanomaterials in an environmentally friendly way, and is a guideline for the subsequent research of Bi $_{2}\text{Te}_{3}$ -based thermoelectric materials.