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

In this work,we show significantly enhanced thermoelectric performance in Cu2SnSe3via a synergistic effect of Cd-doping and CuGaTe2alloying 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 ～0.68 was obtained for Cu2Sn0.93Cd0.07Se3sample at823 K,which is about four times higher than that of the pristine sample(zT=0.18 at 773 K).Furthermore,Cu2Sn0.93Cd0.07Se3was alloyed with CuGaTe2to 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)0.06sample,with a high average zT(zTave) value of0.30 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 Cu2SnSe3based compounds.