Characterization and thermoelectric properties of polyol method-synthesized (Cu7Te4)1 − x(Ag2Te)x (x = 0, 0.03) nanocomposites

(Cu 7 Te 4 ) 1 − x (Ag 2 Te) x ( x = 0, 0.03) nanocomposites (NCs) of crystallite size in the range of 23–31 nm have been synthesized successfully using only diethylene glycol. Detailed characterizations show the single-phase and disk-shaped nanoparticles (NPs) of hexagonal Cu 7 Te 4 with average thickness of 42 nm and width of 75 nm. Hydrodynamic diameter is found to be in the range of 308–351 nm and the zeta potential values indicate that the NCs are dispersible and stable in deionized water. Small positive Seebeck coefficient α with relatively high electrical conductivity σ indicates their highly degenerate p-type semiconducting nature with a signature of the energy filtering in electron transport. The barrier heights of 1.4 and 4.1 meV for x = 0 and 0.03, respectively, confirm their highly degenerate semiconducting nature. The thermoelectric power factor of 9.7 μW/mK 2 for 0.03 is nearly 45% enhancement compared to that of Cu 7 Te 4 and 242 times that of Bi 2 − x Cu x S 3 NPs showing great potential of this approach.