Synergistic Influence of Cu Intercalation on Electronic and Thermal Properties of n-Type CuxBi2Te2.7Se0.3 Polycrystalline Alloys

Cho, Hyun-Jun; Shin, Weon Ho; Choo, Sung-sil; Kim, Ji-Il; Yoo, Joonyeon; Kim, Sang Il

doi:10.1007/s11664-019-06973-6

Cited by 5 publications

(3 citation statements)

References 22 publications

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“…A possible explanation would be that intercalated Cu and Te/Se disorder already provide enough point defect scattering, so that Pd substitution would not contribute further in reducing κ latt . Scattering from Cu is known to be rather effective [12]. Consequently, the κ tot value at 300 K showed a significant increase due to the increased κ elec , whereas that at 480 K increased only slightly, together with the decrease in κ bp , seen in Figure 4a.…”

Section: (7)mentioning

confidence: 89%

“…Meanwhile, the influence of doping on n-type Bi 2 (Te,Se) 3 alloys has not been investigated as much as that of doping on p-type (Bi,Sb) 2 Te 3 alloys. It has been found that Cu intercalation in n-type Bi 2 (Te,Se) 3 alloys is a very effective approach to reducing the lattice thermal conductivity (κ latt ) by introducing additional point defect scattering centers [12]. However, the accompanying modification of carrier transport properties with the κ latt reduction may reduce the power factor, resulting in zT reduction.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Kim

Lee

et al. 2019

Materials

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Doping is known as an effective way to modify both electrical and thermal transport properties of thermoelectric alloys to enhance their energy conversion efficiency. In this project, we report the effect of Pd doping on the electrical and thermal properties of n-type Cu0.008Bi2Te2.7Se0.3 alloys. Pd doping was found to increase the electrical conductivity along with the electron carrier concentration. As a result, the effective mass and power factors also increased upon the Pd doping. While the bipolar thermal conductivity was reduced with the Pd doping due to the increased carrier concentration, the contribution of Pd to point defect phonon scattering on the lattice thermal conductivity was found to be very small. Consequently, Pd doping resulted in an enhanced thermoelectric figure of merit, zT, at a high temperature, due to the enhanced power factor and the reduced bipolar thermal conductivity.

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Section: (7)mentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Kim

Lee

et al. 2019

Materials

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“…The maximum zT of Bi 2 (Te,Se) 3 n-type alloys is below one, while different studies on (Bi,Sb) 2 Te 3 p-type alloys have demonstrated values higher than one. Recently, the zT of polycrystalline Bi 2 (Te,Se) 3 n-type alloys has been improved by doping with the Cu element [3], but it is still lower than the p-type alloys. Considering the fact that the efficiency of a thermoelectric module is closely related to the average material zT between pand n-type thermoelectric materials, the zT of pand n-type alloys needs to be high and similar.…”

Section: Introductionmentioning

confidence: 99%

Reduced Bipolar Conduction in Bandgap-Engineered n-Type Cu0.008Bi2(Te,Se)3 by Sulfur Doping

Shin

Kim

et al. 2020

Energies

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Significant bipolar conduction of the carriers in Bi2Te3-based alloys occurs at high temperatures due to their narrow bandgaps. Therefore, at high temperatures, their Seebeck coefficients decrease, the bipolar thermal conductivities rapidly increase, and the thermoelectric figure of merit, zT, rapidly decreases. In this study, band modification of n-type Cu0.008Bi2(Te,Se)3 alloys by sulfur (S) doping, which could widen the bandgap, is investigated regarding carrier transport properties and bipolar thermal conductivity. The increase in bandgap by S doping is demonstrated by the Goldsmid–Sharp estimation. The bipolar conduction reduction is shown in the carrier transport characteristics and thermal conductivity. In addition, S doping induces an additional point-defect scattering of phonons, which decreases the lattice thermal conductivity. Thus, the total thermal conductivity of the S-doped sample is reduced. Despite the reduced power factor due to the unfavorable change in the conduction band, zT at high temperatures is increased by S doping with simultaneous reductions in bipolar and lattice thermal conductivity.

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Modulation Doping Enables Ultrahigh Power Factor and Thermoelectric ZT in n‐Type Bi₂Te_2.7Se_0.3

Chen

Wang

et al. 2022

Advanced Science

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Bismuth telluride‐based thermoelectric (TE) materials are historically recognized as the best p‐type (ZT = 1.8) TE materials at room temperature. However, the poor performance of n‐type (ZT≈1.0) counterparts seriously reduces the efficiency of the device. Such performance imbalance severely impedes its TE applications either in electrical generation or refrigeration. Here, a strategy to boost n‐type Bi2Te2.7Se0.3 crystals up to ZT = 1.42 near room temperature by a two‐stage process is reported, that is, step 1: stabilizing Seebeck coefficient by CuI doping; step 2: boosting power factor (PF) by synergistically optimizing phonon and carrier transport via thermal‐driven Cu intercalation in the van der Waals (vdW) gaps. Theoretical ab initio calculations disclose that these intercalated Cu atoms act as modulation doping and contribute conduction electrons of wavefunction spatially separated from the Cu atoms themselves, which simultaneously lead to large carrier concentration and high mobility. As a result, an ultra‐high PF ≈63.5 µW cm−1 K−2 at 300 K and a highest average ZT = 1.36 at 300–450 K are realized, which outperform all n‐type bismuth telluride materials ever reported. The work offers a new approach to improving n‐type layered TE materials.

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Synergistic Influence of Cu Intercalation on Electronic and Thermal Properties of n-Type CuxBi2Te2.7Se0.3 Polycrystalline Alloys

Cited by 5 publications

References 22 publications

Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Reduced Bipolar Conduction in Bandgap-Engineered n-Type Cu0.008Bi2(Te,Se)3 by Sulfur Doping

Modulation Doping Enables Ultrahigh Power Factor and Thermoelectric ZT in n‐Type Bi₂Te_2.7Se_0.3

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Synergistic Influence of Cu Intercalation on Electronic and Thermal Properties of n-Type CuxBi2Te2.7Se0.3 Polycrystalline Alloys

Cited by 5 publications

References 22 publications

Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Influence of Pd Doping on Electrical and Thermal Properties of n-Type Cu0.008Bi2Te2.7Se0.3 Alloys

Reduced Bipolar Conduction in Bandgap-Engineered n-Type Cu0.008Bi2(Te,Se)3 by Sulfur Doping

Modulation Doping Enables Ultrahigh Power Factor and Thermoelectric ZT in n‐Type Bi2Te2.7Se0.3

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Modulation Doping Enables Ultrahigh Power Factor and Thermoelectric ZT in n‐Type Bi₂Te_2.7Se_0.3