Maximization of transporting bands for high-performance SnTe alloy thermoelectrics

Tang, Jing; Yao, Zheng; Chen, Z.; Lin, Siqi; Zhang, X.; Xiong, Fen; Li, W.; Chen, Y.; Pei, Yanzhong

doi:10.1016/j.mtphys.2019.03.005

Cited by 49 publications

(32 citation statements)

References 69 publications

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“…Fortunately, the lattice thermal conductivity is the relatively independent parameter among above transport parameters. Therefore, it is feasible to discover some novel TE compounds with intrinsically low thermal conductivity where we can start to tune the electrical transport properties through regulating carrier concentration, scattering mechanisms or band degeneracy, such as the accomplishment in SnSe, Mg 3 Sb 2 and BiCuSeO [9][10][11][12][13][14]. Recent studies have shown that the complex derivative compounds with a series of primitive cells based on Groups II-VI such as ternary I-III-VI 2 , II-IV-V 2 , II-III 2 -VI 4 , I 2 -IV-VI 3 , I 3 -V-VI 4 and quaternary I 2 -II-IV-VI 4 compounds can be synthesized [15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Enhanced thermoelectric performance of ternary compound Cu3PSe4 by defect engineering

et al. 2020

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The diamond-like compound Cu 3 PSe 4 with low lattice thermal conductivity is deemed to be a promising thermoelectric material, which can directly convert waste heat into electricity or vice versa with no moving parts and greenhouse emissions. However, its performance is limited by its low electrical conductivity. In this study, we report an effective method to enhance thermoelectric performance of Cu 3 PSe 4 by defect engineering. It is found that the carrier concentrations of Cu 3-x PSe 4 (x = 0, 0.03, 0.06, 0.09, 0.12) compounds are increased by two orders of magnitude as x [ 0.03, from 1 9 10 17 to 1 9 10 19 cm-3. Combined with the intrinsically low lattice thermal conductivities and enhanced electrical transport performance, a maximum zT value of 0.62 is obtained at 727 K for x = 0.12 sample, revealing that Cu defect regulation can be an effective method for enhancing thermoelectric performance of Cu 3 PSe 4 .

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Section: Introductionmentioning

confidence: 99%

Enhanced thermoelectric performance of ternary compound Cu3PSe4 by defect engineering

et al. 2020

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“…Such an increase in MnTe solubility enables a further N v maximization through an involvement of new highly degenerated transporting band ( Λ ) . A similar effect on increasing N v due to the increase of solubility is also found in SnTe with a MgTe alloying …”

Section: Introductionmentioning

confidence: 71%

“…It should be noted that a high zT realized in above mentioned alloys usually involves a further Cu 2 Te alloying for a sufficiently reduced κ L through the strong phonon scattering by Cu interstitials and an excess of Sn for reducing the carrier concentration. Precipitation of excessive Sn and Cu 2 Te particularly at low temperatures might lead to diffusion problems for practical applications. This motivates the search of single‐phase solid solutions with a comparable or even higher zT .…”

Section: Introductionmentioning

confidence: 99%

“…54 A similar effect on increasing N v due to the increase of solubility is also found in SnTe with a MgTe alloying. 64 It should be noted that a high zT realized in above mentioned alloys usually involves a further Cu 2 Te alloying 54,64,65 for a sufficiently reduced κ L through the strong phonon scattering by Cu interstitials 52 and an excess of Sn for reducing the carrier concentration. Precipitation of excessive Sn and Cu 2 Te particularly at low temperatures 54,56,64,65 might lead to diffusion problems for practical applications.…”

Section: Introductionmentioning

confidence: 99%

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Solute manipulation enabled band and defect engineering for thermoelectric enhancements of SnTe

Yao

Tang

et al. 2019

InfoMat

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With years of development, SnTe as a homologue of PbTe has shown great potential for thermoelectric applications in p‐type conduction, and the most successful strategy is typified by alloying for maximizing the valence band degeneracy. Among the known alloy agents, MnTe has been found to be one of the most effective enabling a band convergence for an enhancement in electronic performance of SnTe, yet its solubility of only ~15 at% unfortunately prevents a full optimization in the valence band structure. This work reveals that additional PbTe alloying not only promotes the MnTe solubility to locate the optimal valence band structure but also increases the overall substitutional defects in the material for a substantial reduction in lattice thermal conductivity. In addition, PbTe alloying simultaneously optimizes the carrier concentration due to the cation size effect. These features all enabled by such a solute manipulation synergistically lead to a very high thermoelectric figure of merit, zT of ~1.5 in SnTe with a 20 at% MnTe and a 30 at% PbTe alloying (Sn0.5Mn0.2Pb0.3Te), demonstrating the effectiveness of solute manipulation for advancing SnTe and similar thermoelectrics.

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“…The valley degeneracy can be improved by the convergence of many conducting or valance bands, whose energies are close to each other. This strategy has achieved success in improving thermoelectric performance in many materials [28][29][30][31][32][33] . To see the conducting bands more clearly, we plot the band structures of 2D SnSe with and without 91.48°G B in small energy ranges, as shown in Fig.…”

Section: Seebeck Coefficientsmentioning

confidence: 99%

Enhancing power factor of SnSe sheet with grain boundary by doping germanium or silicon

Sun

Guo

et al. 2020

npj Comput Mater

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Grain boundaries (GBs) widely exist in two-dimensional (2D) and three-dimensional (3D) materials in experiment, which significantly affect the thermoelectric performance because of the scattering effect on the transport of both electron and phonon. Motivated by the research progress in 3D SnSe, we have systematically studied the GBs in a SnSe monolayer including their stable geometric configurations, the effect of GBs on power factor and Seebeck coefficient, and the strategies to improve the performance by using first principles calculations combined with semiclassical Boltzmann theory. We find that the GBs increase the potential energy barrier of carriers and decrease the valley degeneracy of the conducting bands, leading to the reduction of Seebeck coefficient, as compared to that of the pristine SnSe sheet. We further demonstrate that the trapping gap states are effectively eliminated or reduced by doping germanium or silicon, leading to the enhanced electrical conductivity, power factor, and Seebeck coefficient. These findings shed lights on developing practical strategies for modulating the thermoelectric performance of 2D polycrystalline sheets.

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Maximization of transporting bands for high-performance SnTe alloy thermoelectrics

Cited by 49 publications

References 69 publications

Enhanced thermoelectric performance of ternary compound Cu3PSe4 by defect engineering

Enhanced thermoelectric performance of ternary compound Cu3PSe4 by defect engineering

Solute manipulation enabled band and defect engineering for thermoelectric enhancements of SnTe

Enhancing power factor of SnSe sheet with grain boundary by doping germanium or silicon

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