Enhanced Electronic Transport Properties of Se-Doped SnTe1−xSex Nanoparticles by Microwave-Assisted Solvothermal Method

Pure lead-free SnTe has limited thermoelectric potentials because of its low Seebeck coefficients and its relatively large thermal conductivity. Herein, we report on the enhanced electronic transport properties of selenium (Se) doped tin telluride (SnTe1−xSex) nanoparticles (NPs) synthesized by a rapid microwave-assisted solvothermal method and subsequent spark plasma sintering (SPS). Se-doped SnTe NPs, consisting of regular octahedral NPs with sizes from 1.5 μm to 300 nm, are synthesized with sufficient Se doping contents, and detailed structural characterizations reveal a large fraction of grain boundaries in our nanostructures, which is conducive to phonon scattering. Here we demonstrate that it is possible to enlarge the band gap by tuning the doping and composition, ultimately enhancing the power factor. As a result, a power factor value of ∼10.45 μW/cmK2 is attained at 773 K for the SnTe0.97Se0.03 sample, which is 35% higher than that of an undoped SnTe sample. This synthesis and assembly approach provides strategic guidance for maximizing the power factor by nanocrystallization and doping.