Extraordinary role of resonant dopant vanadium for improving thermoelectrics in n-type PbTe

Zhong, Yan; Lv, Fangling; Zhao, Xuanwei; Deng, Qian; An, Xiang; He, Zhengmin; Gan, Lin; Ang, Ran

doi:10.1016/j.mtphys.2022.100955

Cited by 3 publications

(1 citation statement)

References 31 publications

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“…As another useful strategy for engineering the electronic band structure and boosting the Seebeck coefficient of semiconducting compounds, the resonant level has been successfully adopted to improve ZT of several technologically important thermoelectric materials, including PbTe, − SnTe, − and half-Heusler alloys. − More importantly, the strength of the resonant level weakly relies on the solid solubility of elements. Excellent ZT would be expected in p-type PbSe if proper dopants can be found.…”

Section: Introductionmentioning

confidence: 99%

Defect Chemistry Engineering Promotes the Dopability of Cu for an Extraordinary Thermoelectric Performance of Hole-Doped PbSe with Resonant States

et al. 2023

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Cu substitution for Pb (Cu Pb ) has been theoretically predicted to introduce resonant states near the valence band edge of PbSe. However, experimentally, it has not been verified yet due to the extremely low solubility (∼0.3 atom %) of Cu Pb . In this study, we demonstrate that the solubility limit of Cu Pb is extended to at least 1.5 atom % in PbSe by pairing with an identical amount of Cu interstitials (Cu i ), while excess Cu precipitates out as a Cu 2 Se phase at grain boundaries. As a result of the increased dopability of Cu Pb , a significant enhancement of the Seebeck coefficient is realized in hole-doped PbSe because of Cu Pb -induced resonant states. This is also testified by first-principles calculations. Moreover, the rich point defects (Cu Pb , Cu i ), line defects (dislocations), and Cu 2 Se precipitates remarkably frustrate the phonon propagation of PbSe, leading to ∼45% reduction of lattice thermal conductivity (κ lat ) at room temperature. At elevated temperatures (>623 K), there is a dynamic migration of Cu atoms from Cu 2 Se precipitates to tetrahedral interstices of the PbSe matrix as evidenced by the temperature-variant Hall study and thermal expansion coefficient measurement. This diffusion-like process of Cu further drops the κ lat to ∼0.27 W m −1 K −1 at 823 K. Consequently, a peak ZT of ∼1.8 at 873 K is achieved in the (Cu i ) 0.01 Pb 0.97 (Cu Pb ) 0.01 Na 0.02 Se sample. This work highlights the potential of the defect structure design in innovating new functional materials, particularly high-performance thermoelectrics.

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Section: Introductionmentioning

confidence: 99%

Defect Chemistry Engineering Promotes the Dopability of Cu for an Extraordinary Thermoelectric Performance of Hole-Doped PbSe with Resonant States

et al. 2023

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Compromise Design of Resonant Levels in GeTe‐Based Alloys with Enhanced Thermoelectric Performance

Liang,

Yan,

Geng

et al. 2024

Adv Funct Materials

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Resonant levels (RLs) are expected to increase the density of states (DOS) abruptly, thereby increasing the Seebeck coefficient for a high thermoelectric figure of merit (ZT). However, the negative effects of RLs on reducing the carrier mobility and band gap have rarely been explored. In this work, the pros and cons of resonant‐state doping of group IIIA elements (In, Ga) in GeTe‐based alloys are studied by experimental transport properties and density‐functional‐theory calculations. RLs effects of Fermi level pinning and increased effective mass are strong in Ge0.9‐xInxSb0.1Te but weak in Ge0.9‐y(In0.5Ga0.5)ySb0.1Te, which shows dependence on the hump DOS relative to the background, location of RLs, and energy width of RLs. Using the In‐Ga co‐doping strategy to make a compromise between the DOS, carrier mobility, and bipolar transport, combined with beneficial alloying effects of Pb and Sb, a peak ZT≈ 2.1 at 773 K and a high average ZT≈ 1.43 within 300–773 K can be obtained in Ge0.78In0.005Ga0.005Pb0.1Sb0.07Te. The corresponding single‐leg device shows a remarkable energy conversion efficiency of 13.7% at a temperature difference of 451 K. This work suggests that RLs are not always beneficial for improving ZT, and the compromise design of RLs should be carefully considered to advance ZT.

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Decoupling thermoelectric parameters by the energy-dependent carrier and phonon scattering based on the nano-structuring interface design

Zhu,

Ming,

Jia

et al. 2024

Scripta Materialia

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Extraordinary role of resonant dopant vanadium for improving thermoelectrics in n-type PbTe

Cited by 3 publications

References 31 publications

Defect Chemistry Engineering Promotes the Dopability of Cu for an Extraordinary Thermoelectric Performance of Hole-Doped PbSe with Resonant States

Defect Chemistry Engineering Promotes the Dopability of Cu for an Extraordinary Thermoelectric Performance of Hole-Doped PbSe with Resonant States

Compromise Design of Resonant Levels in GeTe‐Based Alloys with Enhanced Thermoelectric Performance

Decoupling thermoelectric parameters by the energy-dependent carrier and phonon scattering based on the nano-structuring interface design

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