Solvothermal synthesis of wire-like Sn_xSb₂Te_3+x with an enhanced thermoelectric performance

Abstract

Nanostructured tellurides have attracted increasing attention in thermoelectric applications for waste heat recovery and cooling devices. Here, we report on the synthesis of wire-like SnxSb2Te3+x (x = 0, 0.02 and 0.05) nanoparticles using elemental precursors in EG. The enhanced thermoelectric performance was achieved in alloyed samples due to the increase of carrier population in heavy valence band valleys by incorporating Sn(2+) at the Sb(3+) sublattice, enabling the simultaneous realization of low electrical resistivity along with a high Seebeck coefficient as well as the decline of thermal conductivity. Thus a boosted power factor and low thermal conductivity lead to the highest ZT value of 0.58 at 150 °C in the Sn0.02Sb2Te3.02 sample. Our research offers a general wet-chemical route for the preparation of one-dimensional nanomaterials and probably promotes the practical thermoelectric applications of Sb2Te3-based materials at low temperatures.

Eventual Chemical Transformation of Metals and Chalcogens into Metal Chalcogenide Nanoplates through a Surface Nucleation-Detachment-Reorganization Mechanism

“…Strategies to control the dimension, shape, and elemental distribution of multicomponent nanocrystals have been developed extensively. − Understanding the underlying principles of nucleation and growth of the nanocrystals is essential to achieve the rational synthesis of nanocrystals with specific dimension, shape, and elemental distribution. Although the classical nucleation and growth theory describes the formation of single-component nanocrystals, , it fails to clearly elucidate the nucleation and growth of multicomponent nanocrystals synthesized by the coreduction process. − The classical theory assumes that the chemical composition of the nuclei has the same composition with the product nanocrystals, so the whole nucleation and growth process is stoichiometric. − However, even when the concentrations of the precursors are stoichiometric for the target nanocrystal, the elemental concentrations in the reactor keep changing because of the difference in reduction rates of the precursors. The solid–liquid–solid process where the reduced element redissolves into a solution also makes it difficult to keep the reaction stoichiometric. , Such continuous change in the elemental concentrations may cause temporal variations of the crystal structure and chemical composition of the nanocrystals.…”