Optimizing thermoelectric properties of Bi2Te3 via Sb and Se Co-doping: experimental insights and finite elemental simulations using COMSOL

Abstract

In this study, we investigated the impact of antimony (Sb) and selenium (Se) co-dopants on the thermoelectric properties of bismuth telluride (Bi<inf>2</inf>Te<inf>3</inf>). Our findings reveal that Sb doping significantly enhances the electrical conductivity of the material, increasing it by a factor of 2.83 for (Bi<inf>0.98</inf>Sb<inf>0.02</inf>)<inf>2</inf>Te<inf>2.7</inf>Se<inf>0.3</inf>, primarily due to an increase in carrier concentration. The electrical resistivity of pristine Bi<inf>2</inf>Te<inf>3</inf> at 300 K is 2.79 × 10?4 ?·m, which decreases substantially to 0.006 × 10?4 ?·m at 303 K with Sb doping at x = 0.02. Additionally, (Bi<inf>0.96</inf>Sb<inf>0.04</inf>)<inf>2</inf>Te<inf>2.7</inf>Se<inf>0.3</inf> composition achieves the highest power factor of 9.744 × 10?5 W/m·K2 at 300 K, a 3-times improvement over the pristine Bi<inf>2</inf>Te<inf>3</inf> (3.143 × 10?5 W/m·K2). The ZT value of Bi<inf>2</inf>Te<inf>2.7</inf>Se<inf>0.3</inf> is 3.5 times higher than that of the pristine material at 350 K. COMSOL simulations support the experimental findings, revealing a maximum temperature gradient of 35 °C (hot end: 20 °C, cold end: ? 15 °C) for the (Bi<inf>0.98</inf>Sb<inf>0.02</inf>)<inf>2</inf>Te<inf>2.7</inf>Se<inf>0.3</inf> module with comparable p-type and n-type parameters. The increased temperature gradient in the COMSOL simulation correlates with the improved thermoelectric performance observed experimentally, indicating that co-doping Bi<inf>2</inf>Te<inf>3</inf> with Sb and Se effectively enhances its thermoelectric properties. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.