Complex alloying effect on thermoelectric transport properties of Cu2Ge(Se1-xTex)3

摘要

To enhance the thermoelectric performance of Cu2GeSe3,a series of Te-alloyed samples Cu2Ge(Sel-xTex)3 are synthesized and investigated in this work.It is found that the lattice thermal conductivity is reduced drastically for x =0.1 sample,which may be attributed to the point defects introduced by alloying.However,for samples with x ≥ 0.2,the lattice thermal conductivity increases with increasing x,which is related to a less distorted structure.The structure evolution,together with the change in carrier concentration,also leads to a systemically change in electrical properties.Finally,a zT of 0.55@750 K is obtained for the sample with x ＝ 0.3,about 62％ higher than that for the pristine sample.