Enhanced thermoelectric performance of Cu2SnSe3 via synergistic effects of Cd-doping and CuGaTe2 alloying

In this work, we show significantly enhanced thermoelectric performance in Cu2SnSe3 via a synergistic effect of Cd-doping and CuGaTe2 alloying in the temperature range of 300-823 K. Both the electron and phonon transport properties can be simultaneously regulated by Cd doping at Sn site, leading to a higher quality factor. Meanwhile, a maximum figure of merit (zT) value of similar to 0.68 was obtained for Cu2Sn0.93Cd0.07Se3 sample at 823 K, which is about four times higher than that of the pristine sample (zT = 0.18 at 773 K). Furthermore, Cu2Sn0.93Cd0.07Se3 was alloyed with CuGaTe2 to reduce the lattice thermal conductivity in the high-temperature region. Consequently, a further enhanced zT value (0.77, 823 K) was achieved in the (Cu2Sn0.93Cd0.07Se3)(0.94) (CuGaTe2)(0.0)6 sample, with a high average zT (zT(ave)) value of 0.30 between 300 and 823 K. These results demonstrate that Cd-doping combined with CuGaTe2 alloying could be an effective method to enhance zT values of Cu2SnSe3 based compounds.