The effect of Se doping on the growth of Te nanorods

Abstract

In this study, we successfully conducted a series of computationally-assisted experiments, regarding the morphology control and chemical transformation of Te nanorods. The morphology of Te nanorods is controlled by introducing a minute amount of isovalent Se dopant. Density-functional theory calculations predicted the Gibbs surface free energy change due to the adsorbent Se on the major facets of Te nanorods. Encouraged by the theoretical prediction, we conducted experiments on Te nanorod growth and did find significant variation of the morphology of Te nanorods due to Se injection. Furthermore, we demonstrated the chemical transformation of the shape-controlled Te nanorods to binary thermoelectric compounds such as PbTe and Bi2Te3 without losing the tailored morphology. The transformed PbTe and Bi2Te3 have nanoscale grain boundaries as seen from the cross-section HRTEM image. We emphasize that the robust production of morphology-controlled thermoelectric nanorods can be an optimal approach to develop an advanced thermoelectric composite material, by which the multiscale phonon scattering effect can be maximized.