Thermoelectric properties of Ce-doped n-type CexBi2 − xTe2.7Se0.3 nanocomposites


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Ce-doped CexBi2 − xTe2.7Se0.3 (x = 0–0.3) nanopowders were synthesized by the hydrothermal method and the obtained nanopowders were hot-pressed into bulk at 673 K under a pressure of 60 MPa in vacuum. The results show that Ce doping has significant effects on the morphologies of the nanopowders. With increasing Ce doping amount the morphology of the nanopowder changes from nanosheets to nanorods. The thermoelectric (TE) properties measurements show that Ce doping can increase the electrical conductivity greatly, but has little effect on improving Seebeck coefficient and thermal conductivity. There is an optimum value of Ce doping amount. The Ce0.2Bi1.8Se0.3Te2.7 sample shows a highest figure of merit of 0.85 at 413 K as compared to other samples prepared in same conditions.