Hot isostatic pressing-driven fine-tuning of electrical properties in p- and n-type (Bi,Sb)2Te3 thermoelectric materials

Hot isostatic pressing (HIP) is generally used for densification of powders in thermoelectric materials, yet its potential for tuning electrical properties remains underexplored. Herein, we employ hot isostatic pressing as a post-processing for fine-tuning the electrical properties of sintered p - and n -type (Bi,Sb) 2 Te 3 compounds through simultaneous modulation of point defects and microstructure. The HIP process effectively optimizes carrier concentrations via the preferential formation of Sb Te and Bi Te antisite defects, while concurrently improving carrier mobility through grain growth. Based on this synergistic effect, the power factor increases by 11 % and 15 % for p - and n -type samples, respectively. Consequently, owing to the fine-tuned electronic transport properties the calculated device ZT of both p - and n -type samples increased across all tested temperature differences.