Solvothermal synthesis and thermoelectric properties of lanthanum contained Bi-Te and Bi-Se-Te alloys

摘要

Novel nano-sized lanthanum contained Bi_2Te_3 and Bi_2Se_(0.3)Te_(2.7) powders have been synthesized in ethanol at 150 deg C for 24 h via solvothermal processes. It was found that alloying of lanthanum in both Bi_2Te_3 and Bi_2Se_(0.3)Te_(2.7) does not change their crystal structures. The maximal dimensionless figure of merit measured is about 0.11 for La- Bi_2Se_(0.3)Te_(2.7) at 450 K. However, the very low thermal conductivity of 0.4-0.5 W (m K)~(-1) and the moderate Seebeck coefficient of about 170 muV K~(-1) indicate the potential to improve the thermoelectric properties of the material by doping optimization.