Enhancing Thermoelectric Properties of Bi 0.4 Sb 1.6 Te 3 by Embedding SiO 2 Nanoparticles

Thermoelectric performance in Bi 2 Te 3 -materials can be significantly improved by embedding SiO 2 nanoparticles. In this study, SiO 2 nanoparticles (∼80 nm) are synthesized and incorporated into p-type Bi 0.4 Sb 1.6 Te 3 in small amounts (0.01 to 0.06 vol %) using spark plasma sintering. The embedded SiO 2 nanoparticles are confirmed to be well-dispersed within the Bi 0.4 Sb 1.6 Te 3 matrix, which effectively enhances the thermoelectric performance by increasing the power factor and reducing thermal conductivity. Notably, the optimal enhancement was observed at 0.01 vol % SiO 2 nanoparticles. At this sample, the carrier filtering effect was effective, and lattice thermal conductivity decreased by 43% compared to pristine Bi 0.4 Sb 1.6 Te 3 . Consequently, the figure of merit (zT) reached 1.15, a 47% improvement over the pristine sample at room temperature, with a maximum zT of 1.28 at 363 K. These findings highlight that achieving a well-dispersed distribution of SiO 2 nanoparticles in Bi 0.4 Sb 1.6 Te 3 is essential for optimizing both electrical and thermal transport properties, thereby significantly enhancing the overall thermoelectric performance.