Regulation of Ge vacancies through Sm doping resulting in superior thermoelectric performance in GeTe

Zhang, Tingdong; Deng, Songqiang; Zhao, Xu; Ruan, Xuefeng; Qi, N. D.; Chen, Zhiquan; Su, Xianli; Tang, Xinfeng

doi:10.1039/d1ta10711a

Cited by 24 publications

(27 citation statements)

References 67 publications

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“…The τ ave is obtained by the formula τ ave = τ 1 I 1 + τ 2 I 2 (where I 1 + I 2 = 100%), which agrees well with the center of mass of the lifetime spectrum. Therefore, average lifetime τ ave behaves trustworthily to the uncertainties in the decomposition of the lifetime spectrum and is more dependable to characterize the vacancy defects’ properties . As shown in Table , the average positron lifetime (τ ave ) increases gradually from 258.6 ps for Pb 0.98 Na 0.02 Se to 287.3 ps for the x = 0.04 sample, and beyond that it gets saturated.…”

Section: Resultsmentioning

confidence: 87%

“…Therefore, average lifetime τ ave behaves trustworthily to the uncertainties in the decomposition of the lifetime spectrum and is more dependable to characterize the vacancy defects' properties. 38 As shown in Table 2, the average positron lifetime (τ ave ) increases gradually from 258.6 ps for Pb 0.98 Na 0.02 Se to 287.3 ps for the x = 0.04 sample, and beyond that it gets saturated. This indicates the growing population of cation vacancies with increasing Sn content and validates the above conjecture.…”

Section: Defect Chemistry Of Pb 098−x Snmentioning

confidence: 87%

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Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

et al. 2022

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PbSe–SnSe solid solutions have been extensively investigated in the fields of topological physics, optoelectronic conversion, and thermoelectric technology. In this study, we show that minute Sn-doped Pb0.98Na0.02Se behaves quite differently from conventional solid solutions. A dilute amount of Sn dopants induces rich defects (substitutional Sn atoms, interstitial Sn atoms, and cation vacancies) in hole-doped PbSe. Moreover, with growing concentration of Sn, the dominated defect type varies accordingly due to the percolation process of dopants, leading to anomalies in the dependences of thermoelectric properties on compositions. These rich defects increase the thermoelectric performance of p-type PbSe by (i) enhancement of Seebeck coefficient through increased density of states by interstitial Sn atoms; (ii) reduction of lattice thermal conductivity through strong point defect scattering mostly contributed by interstitial Sn atoms and cation vacancies. Moreover, the dynamic migrations of Sn atoms from the interstitial sites to regular lattice sites at elevated temperatures (>623 K) give rise to diffusion-like atomic vibrations that frustrate heat conduction further. Consequently, 1 mol % Sn doping in Pb0.98Na0.02Se yields 20% improvement of thermoelectric performance. This work demonstrates that dilute doping-induced percolation phenomena should be taken into consideration when developing efficient thermoelectric materials.

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Section: Resultsmentioning

confidence: 87%

Section: Defect Chemistry Of Pb 098−x Snmentioning

confidence: 87%

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

et al. 2022

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“…After deducting source and background components, all lifetime spectra can be decomposed into two-lifetime components τ 1 and τ 2 by PATFIT software. The τ 1 and τ 2 are decided by the positron lifetime in a perfect PbSe lattice and in the defect trapping state (vacancies or dislocation), respectively. , I 1 and I 2 stand for corresponding intensities of τ 1 and τ 2 , respectively. All positron lifetime results are summarized in Table .…”

Section: Resultsmentioning

confidence: 99%

Defect Reconfiguration in Hole-Doped PbSe via Minute Te Doping for Significantly Enhanced Thermoelectric Performance

Sun

Cui

Xie

et al. 2023

ACS Appl. Energy Mater.

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Rich defects near the percolation threshold of dilute solid solutions are of fundamental interest to thermoelectric research. Snsubstituted Pb 0.98 Na 0.02 Se (1 mol %) is a typical example that demonstrates how various defects induce intriguing transport phenomena. Unfortunately, the presence of Pb vacancies severely degrades the carrier mobility of samples, and the thermoelectric figure of merit ZT is only marginally improved. In this study, we show that Pb vacancies are effectively inhibited by a facile defect reconfiguration strategy. This is achieved by doping a dilute amount of Te at Se sites of Pb 0.97 Sn 0.01 Na 0.02 Se, where the interstitial Sn ions are pulled back to Pb sites as revealed by the X-ray photoelectron spectroscopy analysis and the positron annihilation test. Consequently, Pb vacancies get occupied, and the room temperature carrier mobility is remarkably recovered from 2.8 to 70 cm 2 V −1 s −1 upon 3 mol % Te doping. Moreover, Te doping reinforces phonon scattering by strain and mass field fluctuations. The lattice thermal conductivity at 300 K goes down to ∼1.7 W m −1 K −1 for Pb 0.97 Sn 0.01 Na 0.02 Se 0.94 Te 0.06 , which is ∼32% lower than that of the Pb 0.97 Sn 0.01 Na 0.02 Se control sample. Altogether, the average ZT value of Pb 0.97 Sn 0.01 Na 0.02 Se between 300 and 773 K is doubled upon 6 mol % Te doping.

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“…A large amount of V Sn acceptors lead to the ultra-high hole carrier concentration and the small thermopower as well as the large κ c , which inhibit the improvement of its ZT value; thus, the most common strategy of improving SnTe thermoelectric properties is to reduce the high carrier concentration. , In PbTe and GeTe , systems, the intrinsic defects are Pb and Ge vacancies, which would scatter charge carriers. Hence, many research studies tried to inhibit the cation vacancies by increasing the cation content or introducing extrinsic dopants to improve the μ. − Because the intrinsic defects in Cu-containing chalcogenides CuInS 2 and Cu 2 ZnSnS 4 are V Cu and Cu Zn antisite, we speculate that the intrinsic point defects in Cu 2 SnSe 3 are V Cu and/or Cu Sn antisite defects. Whereas Cu–Se bonds form a hole conduction network in Cu 2 SnSe 3 , V Cu would damage the carrier conduction paths and scatter the charge carrier drastically.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study of Intrinsic and Extrinsic Point Defects and Their Effects on Thermoelectric Properties of Cu₂SnSe₃

et al. 2023

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Current understanding of the intrinsic point defects and potential extrinsic dopants in p-type Cu 2 SnSe 3 is limited, which hinders further improvement of its thermoelectric performance. Here, we show that the dominant intrinsic defects in Cu 2 SnSe 3 are Cu Sn and V Cu under different chemical conditions, respectively. The presence of V Cu will damage the hole conduction network and reduce hole mobility. Besides, we find that the substitution of Al, Ga, In, Cd, Zn, Fe, and Mn for Sn can inhibit the formation of V Cu ; introducing Cu Sn , Fe Sn , Mn Sn , and Ni Cu defects can significantly enhance electronic density of states near the Fermi level due to the contribution of 3d orbitals. Therefore, increasing the Cu content and/or introducing the above beneficial dopants appropriately are expected to cause enhancement of carrier mobility and/or thermopower of Cu 2 SnSe 3 . Furthermore, introducing

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Regulation of Ge vacancies through Sm doping resulting in superior thermoelectric performance in GeTe

Abstract: A high thermoelectric figure of merit ZT of 2.5 at 730 K is achieved in p-type Ge1−xSmxTe through synergetic optimization of electrical and thermal transport properties. Sm doping effectively suppresses...

Cited by 24 publications

References 67 publications

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Defect Reconfiguration in Hole-Doped PbSe via Minute Te Doping for Significantly Enhanced Thermoelectric Performance

Theoretical Study of Intrinsic and Extrinsic Point Defects and Their Effects on Thermoelectric Properties of Cu₂SnSe₃

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Regulation of Ge vacancies through Sm doping resulting in superior thermoelectric performance in GeTe

Abstract: A high thermoelectric figure of merit ZT of 2.5 at 730 K is achieved in p-type Ge1−xSmxTe through synergetic optimization of electrical and thermal transport properties. Sm doping effectively suppresses...

Cited by 24 publications

References 67 publications

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Percolation Process-Mediated Rich Defects in Hole-Doped PbSe with Enhanced Thermoelectric Performance

Defect Reconfiguration in Hole-Doped PbSe via Minute Te Doping for Significantly Enhanced Thermoelectric Performance

Theoretical Study of Intrinsic and Extrinsic Point Defects and Their Effects on Thermoelectric Properties of Cu2SnSe3

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Theoretical Study of Intrinsic and Extrinsic Point Defects and Their Effects on Thermoelectric Properties of Cu₂SnSe₃