| Title |
Enhancement of High-Temperature Thermoelectric Properties in Pd-decorated Bi-Sb-Te System |
| Authors |
박현진(Hyunjin Park); 천승현(Seunghyun Chun); 김준수(Junsu Kim); 김영우(Young-woo Kim); 이창우(Changwoo Lee); 서원선(Won-seon Seo); 김상일(Sang-il Kim); 이효선(Hyosun Lee); 김현식(Hyun-sik Kim) |
| DOI |
https://doi.org/10.3365/KJMM.2025.63.1.43 |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Keywords |
Effective Mass model; Pd decoration; Weighted mobility; Bipolar conduction; Bi0.5Sb1.5Te3 |
| Abstract |
Bismuth antimony telluride (Bi-Sb-Te)-based alloys remain the dominant choice for near-roomtemperature thermoelectric cooling applications. One of the most studied approaches to improve the thermoelectric performance of Bi-Sb-Te alloys has been a nanostructuring strategy, to suppress the lattice thermal conductivity. This study investigates the impact of incorporating reduced pyrolyzed Pd acetate within a Bi0.5Sb1.5Te3 matrix, building upon recent advancements in nanostructured Bi-Sb-Te alloys. While Pd acetate addition lowers the thermoelectric figure-of-merit (zT) at low temperatures, due to a corresponding increase in carrier concentration, it significantly enhances zT at higher temperatures. Notably, at 473 K, the addition of 0.02 wt.% Pd acetate increased zT by 32% (from 0.41 to 0.54) compared to the pristine sample. Above 423 K, the average zT improved by approximately 21% (from 0.44 to 0.53) in the 0.02 wt.% Pd acetate sample, primarily due to reduced bipolar conduction. Effective Mass (EM) modeling was employed to analyze band parameters. With the addition of Pd acetate, the density-of-states effective mass (md*) generally increased, while non-degenerate mobility (μ0) decreased. At 473 K, the thermoelectric quality factor increased by 42% (from 0.125 to 0.177) with 0.02 wt.% Pd acetate addition, indicating an improved theoretical maximum zT. These findings demonstrate the potential of incorporating Pd acetate for enhancing high-temperature thermoelectric performance in Bi0.5Sb1.5Te3.(Received 20 September, 2024; Accepted 7 November, 2024) |