High thermoelectric performance of fullerene doped Bi_0.5Sb_1.5Te₃ alloys

Highlights: • A high thermoelectric ZT 1.47 ± 0.07 (at 358 K) of Bi0.5Sb1.5Te3 bulk alloys was achieved by incorporation of small amount of C60. • The C60 doped Bi0.5Sb1.5Te3 bulk alloys have the potential as high performance thermoelectric materials near room temperature. • The thermal conductivity was dramatically reduced to 0.4 W/(mK) at 358 K after C60 doping. - Abstract: In this paper, we report our recent experimental findings on the enhancement of thermoelectric performance of C₆₀ doped Bi_0.5Sb_1.5Te₃ bulk alloys. Incorporation of a small amount of C₆₀ significantly reduces the crystalline particle size and leads to closely packed nanostructure, whilst slightly improve the electric conductivity in the measured temperature range. In addition, a minimum thermal conductivity of 0.4 W/(mK) at 358 K was observed, which is identified to be caused by the strong lattice phonon scattering at grain boundaries, yielding a high figure-of-merit ZT = 1.47 ± 0.07 at 358 K. Our results demonstrate that the materials can be used for the development of advanced thermoelectrics.