Microstructural Engineering for Power Factor and ZT Optimization in Cu Alloyed n-Type Bi 2– x Sb x Te 3 Thermoelectric Materials

High Resolution Image Download MS PowerPoint Slide Bismuth telluride (Bi 2 Te 3 ) alloys are widely used thermoelectric (TE) materials for near-room-temperature energy conversion. The performance of TE devices in this range critically depends on n-type Bi 2 Te 3 alloys for performance parity with that of their p-type counterparts. This study presents a strategy for tuning the thermoelectric properties of selenium-free n-type Bi 2– x Sb x Te 3 (BST) through controlled copper (Cu) alloying. Cu incorporation via ball milling enhanced the Seebeck coefficient but reduced electrical conductivity due to the formation of coarse Cu-rich precipitation. Subsequent melt-spinning recovered conductivity and promoted uniform Cu dispersion while inducing beneficial point defects and lowering lattice thermal conductivity. These combined effects shifted the peak ZT value toward room temperature, achieving…