Enhanced thermoelectric performance of Bi2Te3 by La2O3 dispersion

Bi2Te3 is a classical thermoelectrical material and has been applied widely in commerciality. In this paper, the influence of La2O3 dispersion as the nanosecond phase on the thermoelectric properties of Bi2Te3 was investigated. The Bi2Te3 nanopowders were prepared by the hydrothermal method. After adding the La2O3 nanopowders according to Bi2Te3 + [Formula: see text] wt% La2O3 ([Formula: see text], 0.5, 1.0, 1.5), they were hot pressed into bulks in vacuum. The experimental results showed that the dispersed La2O3 as the nanosecond phase could enhance phonon scattering and suppress the thermal conductivity of Bi2Te3 effectively. Although their electrical resistivity increased due to the deteriorated carrier mobility, as a combined effect, the thermoelectric merit value (ZT) of the Bi2Te3 + 0.5 (or 1.0) wt% La2O3 was optimized and reached 0.61 at about 455 K.