High Thermoelectric Performance in AgBiSe₂-Incorporated n-Type Bi₂Te_2.69Se_0.33Cl_0.03

Abstract

Bismuth telluride-based (Bi2Te3) alloys have long been considered the best thermoelectric (TE) materials at room temperature. However, the n-type Bi2Te3 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 AgBiSe2 can concurrently regulate the electrical and thermal transport properties as well as improve the mechanical performance of n-type Bi2Te2.69Se0.33Cl0.03 for high thermoelectric performance. Among these, AgBiSe2 effectively enhanced the Seebeck coefficients of n-type Bi2Te2.69Se0.33Cl0.03 due to the reduced carrier concentration and reduced the thermal conductivity of n-type Bi2Te2.69Se0.33Cl0.03 owing to the enhanced phonon scattering by AgBiSe2 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 % AgBiSe2-incorporated Bi2Te2.69Se0.33Cl0.03, which are ∼25.62 and ∼23.36% larger than those of Bi2Te2.69Se0.33Cl0.03, respectively. This work proves that the incorporation of AgBiSe2 is an efficient way to improve the thermoelectric performance of bismuth telluride-based materials.

High Thermoelectric Performance in Cu-Doped Bi2Te2.7Se0.33 Due to Cl Doping and Multiscale AgBiSe2

“…The κ lat of ABS-incorporated Bi 1.995 Cu 0.005 Te 2.69 Se 0.33 Cl 0.03 is lower than that of Bi 1.995 Cu 0.005 Te 2.69 Se 0.33 Cl 0.03 . The minimum κ lat is only about ∼0.28 W m −1 K −1 at 353 K for the x = 0.65 wt % ABS sample, which is lower than the previously reported value (0.35 W m −1 K −1 ) 37 and also nearly the ultralow κ lat of ∼0.27 W m −1 K −1 reported in GaAs-incorporated Bi 2 Te 2.7 Se 0.3 . 23 This low κ lat is attributed to the enhanced phonon scattering by multiscale ABS as explained above (Figures 4 and 6).…”

“…This enhancement is attributed to the reduction in lattice thermal conductivity, i.e., from 0.32 W m –1 K –1 to ∼0.28 W m –1 K –1 , achieved due to enhanced phonon scattering by multiscale ABS in the matrix and the relatively enhanced Seebeck coefficient. These values exceed our previously reported results ( ZT = ∼1.21 and κ lat = 0.35 W m –1 K –1 ) . Our study demonstrates the usefulness of combining doping and incorporation in Bi 2 Te 3 -based thermoelectric materials to realize high thermoelectric performance.…”

“…Electronic transport parameters of Bi 1.995 Cu 0.005 Te 2.69 Se 0.33 Cl 0.03 + x wt % ABS. (a) Electrical conductivities; (b) Seebeck coefficients; (c) room temperature S in our work and other literatures; and (d) power factors.…”

“…These values exceed our previously reported results (ZT = ∼1.21 and κ lat = 0.35 W m −1 K −1 ). 37 Our study demonstrates the usefulness of combining doping and incorporation in Bi 2 Te 3 -based thermoelectric materials to realize high thermoelectric performance.…”

“…When performing the spark plasma sintering process on Bi 1.995 Cu 0.005 Te 2.69 Se 0.33 Cl 0.03 + x wt % ABS mixtures, ABS plays a vital role as a site where grain growth is anchored. It helps stabilize the grain structure at high temperatures and, to an extent, enhances the hardness …”