Enhanced Thermoelectric Performance of CuSe via Nanostructure and Compositional Gradient.

Forming co-alloying solid solutions has long been considered as an effective strategy for improving thermoelectric performance. Herein, the dense Cu(MnFeNi)Se ( = 0-0.09) with intrinsically low thermal conductivity was prepared by a melting-ball milling-hot pressing process. The influences of nanostructure and compositional gradient on the microstructure and thermoelectric properties of CuSe were evaluated. It was found that the thermal conductivity decreased from 1.54 WmK to 0.64 WmK at 300 K via the phonon scattering mechanisms caused by atomic disorder and nano defects. The maximum value for the Cu(MnFeNi)Se sample was 1.08 at 750 K, which was about 27% higher than that of a pristine sample.