High Carrier Mobility and High Figure of Merit in the CuBiSe<sub>2</sub> Alloyed GeTe

Yin, Liang‐Cao; Liu, Wei‐Di; Li, Meng; Sun, Qiang; Gao, Han; Wang, De‐Zhuang; Wu, Hao; Wang, Yifeng; Shi, Xiao‐Lei; Li, Qingfeng; Chen, Zhigang

doi:10.1002/aenm.202102913

Cited by 63 publications

(31 citation statements)

References 53 publications

(92 reference statements)

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“…The bonding of V–Te (2.797 Å) is shorter than that of Ge–Te (3.005 Å) in C-GeTe, and electrons are localized after V doping, suggesting that Ge s electrons are reduced after V doping, and that V can reduce Δ E . Besides, Ta, Cu, Zn, Cr, La, and I are found to reduce the Δ E values of GeTe in our studies (Figure b). In this regard, the overall thermoelectric performance has been enhanced.…”

Section: Enhancing Electronic Transportmentioning

confidence: 88%

Chemistry in Advancing Thermoelectric GeTe Materials

Hong

Chen

2022

Acc. Chem. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS:The ever-growing energy crisis and the deteriorated environment caused by carbon energy consumption motivate the exploitation of alternative green and sustainable energy supplies. Because of the unique advantages of zero-emission, no moving parts, accurate temperature control, a long steady-state operation period, and the ability to operate in extreme situations, thermoelectrics, enabling the direct conversion between heat and electricity, is a promising and sustainable option for power generation and refrigeration. However, with increasing application potentials, thermoelectrics is now facing a major challenge: developing high-performance, Pb-free, and lowtoxic thermoelectric materials and devices.As one group of promising candidates, GeTe derivatives have the potential to replace the widely used thermoelectric materials containing highly toxic elements.In this Account, we summarize our recent progress in developing highperformance GeTe-based thermoelectric materials via exploring innovative strategies to enhance electron transports and dampen phonon propagations. First, we fundamentally illustrate the underlying chemistry and physical reason for an intrinsically high carrier concentration in GeTe, which enormously restrains the thermoelectric performance of GeTe. From our theoretical calculations, the formation energy of Ge vacancy is the lowest among the defects in GeTe, energetically favoring Ge vacancies in the lattice and leading to intrinsically high carrier concentrations. Accordingly, aliovalent doping/alloying is proposed to increase the formation energy of Ge vacancies and decrease the carrier concentration to the optimal level. We then outline the newly developed method to refine the band structures of GeTe with tuned electronic transport. On the basis of the molecular orbital theory, the energy offset between two valence band edges at the L and Σ points in GeTe should be ascribed to the slightly different Ge_4s orbital characters at these two points, which guides the screening of dopants for band convergence. Besides, the Rashba spin splitting is explored to increase the band degeneracy of GeTe. Afterward, we analyze the dampened phonon propagation in GeTe to minimize its lattice thermal conductivity. Alloying with the heavy Sb atoms can shift the optical phonon modes toward low frequency and reinforce the interaction of optical and acoustic phonon modes so that the inherent phonon scattering is enhanced. In addition, planar vacancies and superlattice precipitates can significantly strengthen phonon scattering to result in ultralow lattice thermal conductivity. After that, we overview the finite elemental analysis simulations to optimize the device geometry for maximizing the device performance and introduce the as-developed prototype GeTe-based thermoelectric device. In the end, we point out future directions in the development of GeTe for device applications. The strategies summarized in this Account can serve as references for developing wide materi...

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Section: Enhancing Electronic Transportmentioning

confidence: 88%

Chemistry in Advancing Thermoelectric GeTe Materials

Hong

Chen

2022

Acc. Chem. Res.

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“…26,42−44 As electron donors, Pt atoms may also improve the value of μ by irritating the correlations between two neighboring Bi 2 S 3 layers. 28,45−47 In addition, the small electronegativity difference between Pt and Bi can also suppress the carrier scattering, 48 and thus, multiple effects endow Bi 2 S 3 −Pt 1 with a higher μ than that of Bi 2 S 3 substrate. When considering the aggregation of Pt n clusters (Figure S3e), both μ and σ decrease, in which the scattering mechanism of Bi 2 S 3 −2.5 wt % Pt n could be nanoprecipitate scattering and APS.…”

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confidence: 99%

Mass Production of Pt Single-Atom-Decorated Bismuth Sulfide for n-Type Environmentally Friendly Thermoelectrics

Zhao

Jin

et al. 2022

Nano Lett.

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Single-atom materials are widely explored in catalysis, batteries, sensors, etc. However, limited by mass production and centimeter-scale assembly, they are rarely studied in thermoelectrics. Herein, we demonstrate a solvothermal synthesis assisted by a syringe-pump method to yield Bi 2 S 3supported Pt single-atom materials (Bi 2 S 3 −Pt 1 ) at a 10 g scale. Different from Pt n clusters, Pt 1 single atoms can increase carrier concentration at a high doping efficiency and provide a unique atomic environment to enhance carrier mobility, and an enlarged effective mass leads to an enhanced Seebeck coefficient. As a result, a high power factor (348 μW m −1 K −2 ) is achieved at 823 K. Benefiting from the scattering of phonons by Pt 1 atomic sites, a minimum thermal conductivity of 0.37 W m −1 K −1 is achieved. Consequently, the Bi 2 S 3 −0.5 wt % Pt 1 realizes a record-high zT of ∼0.75 at 823 K, being among the best in the state-of-the-art n-type environmentally friendly metal sulfides. The enhancement of the carrier mobility and suppression of the thermal conduction by the unique Pt 1 single atoms will inspire various fields, as exemplified by electronic devices and thermal management.

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“…This can be understood by the reduction of Ge vacancies/precipitates for a weak charge carrier scattering by impurities. 28,45 It can be seen that room-temperature carrier mobility significantly increases from 53.3 cm 2 V −1 s −1 in pristine GeTe to 66.5 cm 2 V −1 s −1 in the x = 0.04 sample. By additional Bi doping, the hole concentration further decreases from 3.45 × 10 20 cm −3 in (GeTe) 0.96 (CuI) 0.04 to 1.09 × 10 20 cm −3 in (Ge 0.96 Bi 0.04 Te) 0.96 (CuI) 0.04 .…”

Section: Resultsmentioning

confidence: 95%

“…2f, the room-temperature power factor of the CuI–Bi codoped GeTe in this work is higher than most of the literature results. 27,35,37,44,45…”

Section: Resultsmentioning

confidence: 99%