Preparation of 1-D/3-D structured AgNWs/Bi2Te3 nanocomposites with enhanced thermoelectric properties

A novel and facile approach is demonstrated to dramatically enhance thermoelectric properties by means of introducing one-dimensional (1-D) silver nanowires (AgNWs) into a three-dimensional (3-D) Bi2Te3 matrix in order to construct 1-D/3-D structured nanocomposites. The influence of different concentrations of AgNWs on the morphology and thermoelectric properties of Bi2Te3 is investigated in detail. The results show that the dispersed AgNWs effectively suppress grain growth and form new interfaces with the Bi2Te3 matrix. In contrast to pure bulk Bi2Te3, almost all bulk samples dispersed with AgNWs exhibit the much lower thermal conductivity and higher power factors. Consequently, the maximum ZT of the AgNW-dispersed Bi2Te3 nanocomposites is amazingly found to be 343% higher than that of the pure Bi2Te3. These results demonstrated that the dispersion of AgNWs could form new interfaces with the matrix and introduce defects to cause strong scattering of long-wavelength phonons, and therefore significantly reduce the lattice thermal conductivity. Our study confirms that introducing 1-D nanodispersoids into a 3-D thermoelectric matrix is promising approach to improving ZT values significantly.