Improvement of thermoelectric performance of copper-deficient compounds Cu_2.5+δIn_4.5Te₈ (δ = 0–0.15) due to a degenerate impurity band and ultralow lattice thermal conductivity

Abstract

Improvement of thermoelectric performance of copper-deficient compounds Cu2.5+δIn4.5Te8 (δ = 0–0.15) due to degenerate impurity band (IB) and ultralow lattice thermal conductivity.

Synergistic Regulation of Phonon and Electronic Properties to Improve the Thermoelectric Performance of Chalcogenide CuIn1−xGaxTe2:yInTe (x = 0–0.3) with In Situ Formed Nanoscale Phase InTe

“…Figure 2c showcases that the power factor (PF = α 2 σ) follows the trend of the electrical conductivity. The highest PF value is 13.8 μW cm −1 K −2 for the sample at x = 0.2 and 687 K. This value is much higher than those of most pure CuInTe 2 or its based chalcogenides reported (3.82–11.7 μW cm −1 K −2 ) and comparable to those of Cu 0.95(6) InTe 2 (13.0–13.7 μW cm −1 K −2 ) and Cu 0.95(6) InTe 2 + In 2 O 3 (14.45μW cm −1 K −2 ) . However, the PF value is much lower than the estimated value of CuInTe 2 (PF > 26 μW cm −1 K −2 at 800 K), suggesting that there is still a big room for the enhancement.…”

“…Generally, the α value increases with increase in Ga content (x value), and it converges gradually above ≈680 K at x ≤ 0.2. 2020, 6,1901141 reported (3.82-11.7 µW cm −1 K −2 ) [2,10,30,[33][34][35][36][39][40][41][42] and comparable to those of Cu 0.95(6) InTe 2 (13.0-13.7 µW cm −1 K −2 ) [1,9] and Cu 0.95(6) InTe 2 + In 2 O 3 (14.45µW cm −1 K −2 ). The electrical conductivity (σ) increases as the x value increases before it starts to fall at x > 0.2, and at x = 0.3 the electrical conductivity decreases significantly, as shown in Figure 2b.…”

“…Recently, we have developed several kinds of Cu‐In‐Te derivatives, such as (Cu 2 Te) δ Cu 1.15 In 2.29 Te 4 (δ = 0–0.075), Cu 2.5 + δ In 4.5 Te 8 (δ = 0–0.15), and (Cu 2 Te) x (Cu 3.52 In 4.16 Te 8 ) and reduced their lattice part κ L to 0.3 W K −1 m −1 . However, the TE performance of these materials does not still fully optimize as the highest PF value is only 3.82–10.59 μW m −1 K −2 . This implies that, to our best knowledge, the versatility of the ternary Cu‐In‐Te chalcogenides as TE candidates has not been explored to the fullest to date.…”

“…In contrast, Luo et al succeed in enhancing the power factor (PF) from 8.3 µW m −1 K −2 (at ≈700 K) to 14.45 µW m −1 K −2 (at ≈500 K) through introducing a nanoscale phase (In 2 O 3 ) in CuInTe 2 [31] ; however, the lattice parts κ L do not reduce largely. 15 In 2.29 Te 4 (δ = 0-0.075), [33] Cu 2.5 + δ In 4.5 Te 8 (δ = 0-0.15), [34] and (Cu 2 Te) x (Cu 3.52 In 4.16 Te 8 ) [35] and reduced their lattice part κ L to 0.3 W K −1 m −1 . 15 In 2.29 Te 4 (δ = 0-0.075), [33] Cu 2.5 + δ In 4.5 Te 8 (δ = 0-0.15), [34] and (Cu 2 Te) x (Cu 3.52 In 4.16 Te 8 ) [35] and reduced their lattice part κ L to 0.3 W K −1 m −1 .…”

“…15 In 2.29 Te 4 (δ = 0-0.075), [33] Cu 2.5 + δ In 4.5 Te 8 (δ = 0-0.15), [34] and (Cu 2 Te) x (Cu 3.52 In 4.16 Te 8 ) [35] and reduced their lattice part κ L to 0.3 W K −1 m −1 . [33][34][35] This implies that, to our best knowledge, the versatility of the ternary Cu-In-Te chalcogenides as TE candidates has not been explored to the fullest to date. [33][34][35] This implies that, to our best knowledge, the versatility of the ternary Cu-In-Te chalcogenides as TE candidates has not been explored to the fullest to date.…”