Realizing the Interface Tuned Thermoelectric Transport Performance in Bi2Te3-Based Hierarchical Nanostructures

Abstract

Hierarchical Te/Bi2Te3 and Bi2Te3 nanostructures are synthesized by using a one-pot solvothermal method and sintered into pellets by spark plasma sintering (SPS), individually. The thermoelectric properties measurement indicates the electrons/phonon transport is directly influenced by interface state of the hierarchical nanostructures. As compared to Te/Bi2Te3 heterostructures, the higher energy barrier at the interface of homostructured Bi2Te3 (71 meV) leads to the energy filtering effect on the electronic transport and the optimized power factor in the Bi2Te3 pellet. The thermal conductivity is remarkably reduced because of the strong scattering between phonons and high-density defects in both samples. As a result, an enhanced ZT value (0.58) of the Bi2Te3 nanowires was obtained at 353 K. Importantly, the average ZT (0.56), which is comparable to the peak ZT of both samples, is dramatically improved in these hierarchical nanostructures in the temperature range of 313–433 K.