Rare three-valence-band convergence leading to ultrahigh thermoelectric performance in all-scale hierarchical cubic SnTe

Li, Fan; Liu, Xin; Li, Shu-Rong; Zhang, Xiao-Fan; Ma, Ni; Li, Xin-Jing; Lin, Xin-Yun; Chen, Ling; Wu, Haijun; Wu, Li-Ming

doi:10.1039/d3ee02482b

Cited by 24 publications

(6 citation statements)

References 75 publications

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“…Therefore, the strain should not be caused by phase segregation or composition inhomogeneity. 27,28 We extended our investigation using Raman spectroscopy to examine the strain in perovskite single crystals, building on previous findings that a strained perovskite lattice results in an enhanced Raman signal and peak splitting. 16 The principal Raman peak of the MAPbBr 3 single crystal is typically observed around 85 cm −1 , attributed to the stretching of the Pb−Br bond.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Long-Range Strain in Lead Halide Perovskite Single Crystals

Li,

Tian,

et al. 2024

Crystal Growth & Design

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Strain plays a crucial role in semiconductor materials, often arising from heterointerfaces that involve materials with mismatched lattice parameters or thermal expansion coefficients. As a result, homogeneous single crystals are generally presumed to be strain-free. Contrary to this conventional belief, our study unveils the presence of long-range strain in free-standing lead halide perovskite single crystals. Remarkably, we have observed that spatial temperature inhomogeneity in the solution during crystal growth, induced by processes such as seeding or temperature ramping, leads to the development of long-range and residual strain within these single crystals. Such a strain is found to impact the band gap and carrier mobility of perovskite single crystals. This discovery challenges existing perceptions and introduces a new perspective for understanding and designing the physical and optoelectronic properties of perovskite single-crystalline devices, particularly in applications such as radiation detectors.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Long-Range Strain in Lead Halide Perovskite Single Crystals

Li,

Tian,

et al. 2024

Crystal Growth & Design

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“…The TE properties of materials can be improved by implementing the following approaches: (1) modification of the electronic band structure, Engineering of band convergence , and resonant level can efficiently improve S . This approach has been demonstrated in many TE materials, for instance, SnTe, − PbTe, , half-Heusler alloys, , and Mg 3 Sb 2 ; , (2) adjustment of the defect structures of materials during fabrication can reduce κ L , including point defects (substitution, interstitial defects, and vacancies), − dislocations, − interfaces, − and nanostructures, which have been reported. ,, Because of the large effect of defects on phonon scattering in certain frequency (ω) ranges, full-spectrum phonon scattering can be achieved by including multidimensional defects. − Subsequently, the suppression of κ L at both low and high temperatures has been achieved. − …”

Section: Introductionmentioning

confidence: 99%

High Thermoelectric Performance of SnTe–MnSe with Low Lattice Thermal Conductivity

Wang,

Yuan,

Yang

et al. 2023

ACS Appl. Energy Mater.

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SnTe, a nontoxic thermoelectric (TE) material, has attracted considerable attention due to its lead-free rock-salt, which is comparable to PbTe. In this study, an alloying strategy is used to embed MnSe in the SnTe matrix, which results in synergistic effects of valence-band convergence and defect engineering. The MnSealloyed SnTe achieves an excellent thermoelectric performance. Mn-and Se-substitutions of Sn and Te sites, respectively, induce the convergence of valence bands and increase the Seebeck coefficients of samples, which lead to competitive power factors. In addition, the numerous defects introduced by alloying with MnSe act as phonon scattering sources to effectively lower the lattice thermal conductivity. The SnTe−10%MnSe sample exhibited a lattice thermal conductivity of 0.44 W m −1 K −1 at 823 K. Ultimately, the SnTe−8%MnSe sample achieved a figure of merit of 1.02, which was 276% higher than that of undoped SnTe. This study offers an approach to enhancing Te-based thermoelectric materials with low lattice thermal conductivity and to advancing the fundamental understanding of SnTe.

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“…To address this issue, various doping strategies have been proposed, such as Mn-doping, 9,26,27 Mg-doping, 28,29 Mg/Ag co-doping, 30 and AgBiSe 2 alloying, 31 and they were found to reduce the energy separation between the valence band maxima. Li et al 32 reported a rare three valence band convergence in SnTe via MnCdTe 2 alloying. As a result, a promising zT of 2.0 at 900 K was achieved.…”

Section: Introductionmentioning

confidence: 99%