Facile rapid synthesis of a nanocrystalline Cu2Te multi-phase transition material and its thermoelectric performance

Abstract

A highly efficient facile method was used to synthesize Cu₂Te via spark plasma sintering (SPS) of high-energy ball-milled elemental powders, followed by annealing, which dramatically reduced the whole process time. The multiple phase transitions of Cu₂Te over an extensive temperature range were determined using a combination of high temperature X-ray diffraction (HTXRD) and differential scanning calorimetry (DSC). This merit endows Cu₂Te with the ability to trigger multiple critical scatterings from room temperature up to 900 K. Microscopic investigation showed that the Cu₂Te prepared by this rapid method possesses tiny dispersive precipitates, with sizes in the range of 50–100 nm, that could serve as obstacles for the transfer of mid-wavelength phonons. As a result, a ZT value of ∼0.52 at 1000 K was obtained for the sample annealed for 10 h after SPS.