Enhancing Thermoelectric Performance of n-Type Bi 2 Te 2.7 Se 0.3 through Incorporation of Amorphous Si 3 N 4 Nanoparticles.

Bi 2 Te 3 -based thermoelectric (TE) materials are the state-of-the-art compounds for commercial applications near room temperature. Nevertheless, the application of the n-type Bi 2 Te 2.7 Se 0.3 (BTS) is restricted by the comparatively low figure of merit (ZT) and intrinsic embrittlement. Here, we show that through dispersion of amorphous Si 3 N 4 ( a -Si 3 N 4 ) nanoparticles both 14% increase in power factor (at 300 K) and 48% decrease in lattice thermal conductivity are simultaneously realized. The increased power factor comes from enhanced thermopower and reduced electrical resistivity while the reduced lattice thermal conductivity originates mainly from scattering of middle- and low-frequency phonons at the incorporated a -Si 3 N 4 nanoparticles. As a result, a large ZT max = 1.19 (at 373 K) and an average ZT ave ∼ 1.12 (300-473 K) with better mechanical properties are achieved for the BTS/0.25 wt % Si 3 N 4 sample. Present results demonstrate that the incorporation of a -Si 3 N 4 is a promising way to improve TE performance.