High Thermoelectric Performance in AgBiSe 2 -Incorporated n-Type Bi 2 Te 2.69 Se 0.33 Cl 0.03 .

Bismuth telluride-based (Bi 2 Te 3 ) alloys have long been considered the best thermoelectric (TE) materials at room temperature. However, the n-type Bi 2 Te 3 alloys always exhibit poor thermoelectric performance than their p-type counterpart, which severely limits the energy conversion efficiency of thermoelectric devices. Here, we demonstrate that incorporating AgBiSe 2 can concurrently regulate the electrical and thermal transport properties as well as improve the mechanical performance of n-type Bi 2 Te 2.69 Se 0.33 Cl 0.03 for high thermoelectric performance. Among these, AgBiSe 2 effectively enhanced the Seebeck coefficients of n-type Bi 2 Te 2.69 Se 0.33 Cl 0.03 due to the reduced carrier concentration and reduced the thermal conductivity of n-type Bi 2 Te 2.69 Se 0.33 Cl 0.03 owing to the enhanced phonon scattering by AgBiSe 2 as well as its low thermal conductivity nature. Consequently, the simultaneous optimization of electrical and thermal transport properties enables us to achieve a maximum ZT of ∼1.21 (at ∼353 K) and an average ZT ave of ∼1.07 (300-433 K) for 3.5 wt % AgBiSe 2 -incorporated Bi 2 Te 2.69 Se 0.33 Cl 0.03 , which are ∼25.62 and ∼23.36% larger than those of Bi 2 Te 2.69 Se 0.33 Cl 0.03 , respectively. This work proves that the incorporation of AgBiSe 2 is an efficient way to improve the thermoelectric performance of bismuth telluride-based materials.