CuCrSe2: a high performance phonon glass and electron crystal thermoelectric material

The efficient conversion of heat into electricity using a thermoelectric approach requires high performance materials with the thermoelectric figure of merit ZT >= 1. Here we report on bulk CuCrSe2, which exhibits a very high ZT similar to 1 at 773 K. The titled compound exhibits an electrical resistivity of similar to 2.8 m Omega cm, a Seebeck coefficient of similar to 160 mu V K-1, together with very low thermal conductivity similar to 7 mWcm(-1) K-1 at 773 K. The very low thermal conductivity of bulk CuCrSe2 is attributed to phonon scattering by various sources such as (i) superionic Cu ions between the CrSe2 layers, (ii) nanoscale precipitates in the bulk and (iii) natural grain boundaries due to the layered structure of the material. This unusual combination of thermoelectric properties for CuCrSe2 suggests that it is an ideal example of the phonon glass and electron crystal approach.