Unequal bonding in Ag–CuIn₃Se₅-based solid solutions responsible for reduction in lattice thermal conductivity and improvement in thermoelectric performance

Abstract

An unequal bonding in the CuIn3Se5 ternary chalcopyrite is responsible for the reduction in lattice thermal conductivity and improvement in thermoelectric performance.

N-type thermoelectric Ag8SnSe6 with extremely low lattice thermal conductivity by replacing Ag with Cu

“…It is observed that the n H value enhances from 1.93 × 10 16 cm −3 at x = 0 to 8.61 × 10 16 cm −3 at x = 0.1, comparable to that reported by Acharya et al 50 Usually, the mobility μ decreases because of ionized impurity and carrier scattering. 51–53 However, the mobility μ in the present work is laying in the range of 1.17 × 10 2 cm 2 V −1 s −1 and 1.34 × 10 2 cm 2 V −1 s −1 when x value increases from 0 to 0.075 and remains almost unchanged, and then it drops as the x value exceeds 0.075. Such a phenomenon, which is also observed in the Zn 1− x Al x O system, 54 is attributed to a novel micro/nano-structure that provides a favorable crystalline framework for rapid electron transfer.…”

Ultralow Lattice Thermal Conductivity and Extraordinary Thermoelectric Performance in Highly Disordered CuIn7Se11 Layered Compound

“…Temperature‐dependent a) total thermal conductivity κ and b) lattice thermal conductivity κ L of Cu 1−3 x In 7+ x Se 11 ( x = 0–0.029) measured parallel and perpendicular to the SPS pressing direction, respectively. c) Lattice thermal conductivity κ L as a function of temperature for CuIn 7 Se 11 (parallel direction) in comparison to SnSe, [ 25 ] PbSe, [ 24 ] CoSb 3 , [ 27 ] K 2 Bi 8 S 13 , [ 30 ] AgBi 3 S 5 , [ 28 ] CuIn 3 Se 5 , [ 35 ] Cu 4 Sn 7 S 16 , [ 31 ] Cu 9 Fe 9 S 16 , [ 36 ] Cu 17.6 F e17.6 S 32 [ 37 ] and CuIn 5 Se 8 . [ 38 ] d) The relationship between C p / T 3 and T for CuIn 7 Se 11 .…”

“…The low temperature heat capacity reveals a strong coupling between acoustic phonons and low frequency optical phonons resulting from weak In─Se chemical bonds that also lead to low sound velocities. Furthermore, the presence of abundant disordered configurations of Cu, In, and vacancies at In 2 , In 3 , and M sites, combined with atomic-scale slips and flips in the [28] Ag 9 GaTe 6 , [11c] Bi 2 Si 2 Te 6 , [11b] Cu 8 GeSe 6 , [52] CuIn 3 Se 5 , [35] Cu 4 Sn 7 S 16 , [31] Cu 9 Fe 9 S 16 , [36] Cu 17.6 Fe 17.6 S 32 , [37] and CuIn 5 Se 8 . [38] crystalline structure all intensify scattering of phonons, which leads to a low phonon mean free path.…”

“…Both lattice thermal conductivities of CuIn 7 Se 11 decrease monotonically with the increasing temperature and reach 0.18 W m −1 K −1 and 0.37 W m −1 K −1 at 873 K, respectively. The lowest lattice thermal conductivity of 0.17 W m −1 K −1 at 873 K is achieved in the Cu 0.955 In 7.015 Se 11 sample along the direction [25] PbSe, [24] CoSb 3 , [27] K 2 Bi 8 S 13 , [30] AgBi 3 S 5 , [28] CuIn 3 Se 5 , [35] Cu 4 Sn 7 S 16 , [31] Cu 9 Fe 9 S 16 , [36] Cu 17.6 F e17.6 S 32 [37] and CuIn 5 Se 8 . [38] parallel to the pressing direction.…”

“…Moreover, the lattice thermal conductivity of the CuIn 7 Se 11 compound is much lower than those of the conventional thermoelectric materials, such as PbSe [24] and CoSb 3 . [27] Even when comparing to the new thermoelectric materials claiming to possess an intrinsically low thermal conductivity, such as SnSe, [25] K 2 Bi 8 S 13 , [30] AgBi 3 S 5 , [28] CuIn 3 Se 5 , [35] Cu 4 Sn 7 S 16 , [31] Cu 9 Fe 9 S 16 , [36] Cu 17.6 F e17.6 S 32 [37] and CuIn 5 Se 8 , [38] the CuIn 7 Se 11 compound stands out as having the lowest lattice thermal conductivity, as shown in Figure 6c. The effect of the crystal structure and chemical bonding in the CuIn 7 Se 11 compound on the lattice thermal conductivity is discussed below.…”