Enhanced phonon scattering and thermoelectric performance for N-type Bi2Te2.7Se0.3 through incorporation of conductive polyaniline particles

Attaining High Figure of Merit in the N-Type Bi2Te2.7Se0.3-Ag2Te Composite System via Comprehensive Regulation of Its Thermoelectric Properties

“…In addition, the experiments indicate that the thermoelectric performance obtained for BTS/ f Ag 2 Te ( f = 0.3 wt %) samples have good reproducibility and excellent thermal stability (as shown in Figures S9 and S10). It is noted that the ZT max obtained here (1.31) is higher than that for most n-type Bi 2 Te 3 -based alloys reported previously, ,− as shown in Figure b.…”

“…The calculated ZT ave value increases from 0.75 to 1.00, 0.95, 1.16, 1.02, and 0.88 as f increases from 0 to 0.1, 0.2, 0.3, 0.4, and 0.5 wt % (as given in Figure c), respectively. The ZT ave of the Bi 2 Te 2.7 Se 0.3 / f Ag 2 Te ( f = 0.3 wt %) composite sample is much higher than that reported previously, ,− as shown in Figure d.…”

“…N-type Bi 2 Te 3 -based compounds as the state-of-the-art thermoelectric materials near room temperature have attracted extensive attentions. − However, the fact that the inferior performance of n-type Bi 2 Te 3 -based materials than that of p-type counterpart seriously hinders its wide widespread commercial applications. − Currently, most of the work focused on relatively independent κ L , and various strategies to decrease κ L have been developed, such as optimizing preparation techniques, − refining grains, , and compositing nanophases. − A promising example is the addition of polyaniline (PANI) particles into Bi 2 Te 2.7 Se 0.3 (BTS) to effectively scatter phonons of all frequencies, thereby obtaining substantially reduced lattice thermal conductivity and a high ZT ≈1.22 at 345 K . On the other hand, previous work to increase PF by regulating one parameter or another often leads to attending to one thing and losing sight of another; for example, (1) to elevate S via the energy filtering effect (EFE) usually resulted in reduction of electron mobility μ; , (2) to enlarge carrier mobility μ through enhancement of texturing, accompanying which electron concentration increased, leading to elevation of electron thermal conductivity κ e ; , (3) to increase electrical conductivity by elevating carrier concentration n , which inevitably caused enlargement of κ e. Moreover, there are some investigations that tried to improve thermoelectric performance by both enhancing PF and reducing κ L .…”

“…15−17 Currently, most of the work focused on relatively independent κ L , and various strategies to decrease κ L have been developed, such as optimizing preparation techniques, 18−20 refining grains, 21,22 and compositing nanophases. 23−26 A promising example is the addition of polyaniline (PANI) particles into Bi 2 Te 2.7 Se 0.3 (BTS) to effectively scatter phonons of all frequencies, thereby obtaining substantially reduced lattice thermal conductivity and a high ZT≈1.22 at 345 K. 27 increase PF by regulating one parameter or another often leads to attending to one thing and losing sight of another; for example, (1) to elevate S via the energy filtering effect (EFE) usually resulted in reduction of electron mobility μ; 28,29 (2) to enlarge carrier mobility μ through enhancement of texturing, accompanying which electron concentration increased, leading to elevation of electron thermal conductivity κ e ; 30,31 (3) to increase electrical conductivity by elevating carrier concentration n, which inevitably caused enlargement of κ e.…”

Enhanced near-room temperature thermoelectric performance and mechanical strength of n-type BiTeSe materials incorporated with Ag2Se inclusions

“…However, ZT ∥ for BTS-0.15vol%Ag 2 Se displays a maximum value of ∼0.7 in the temperature range of 350 K–400 K, which is 70% larger than the matrix. The average ZT (ZT ave ) in both directions can be obtained by the following formula: 43 where T h and T c represent the hot- and cold-side temperatures, respectively. As shown in Fig.…”