Vacancy-induced dislocations within grains for high-performance PbSe thermoelectrics

Chen, Zhiwei; Ge, Binghui; Li, Wen; Lin, Siqi; Shen, Jiaxu; Chang, Yifan; Hanus, Riley; Snyder, G. Jeffrey; Pei, Yanzhong

doi:10.1038/ncomms13828

Cited by 395 publications

(345 citation statements)

References 62 publications

(87 reference statements)

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“…One effective strategy for ZT improvement is to minimize the lattice thermal conductivity by scattering phonons off crystal defects, e.g., grain boundaries,9, 10, 11, 12, 13, 14 dislocations,15, 16, 17, 18 point defects,19, 20, 21, 22, 23, 24, 25 nanoprecipitates,26, 27, 28, 29, 30 etc. However, thermoelectric power generation demands not only high ZT but also high PF over a wide range of temperature, which directly determines output power density ω, another crucial parameter for power generation 31, 32, 33.…”

Section: Introductionmentioning

confidence: 99%

Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)

Ren

Zhu

et al. 2018

Advanced Science

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Conversion efficiency and output power are crucial parameters for thermoelectric power generation that highly rely on figure of merit ZT and power factor (PF), respectively. Therefore, the synergistic optimization of electrical and thermal properties is imperative instead of optimizing just ZT by thermal conductivity reduction or just PF by electron transport enhancement. Here, it is demonstrated that Nb0.95Hf0.05FeSb has not only ultrahigh PF over ≈100 µW cm−1 K−2 at room temperature but also the highest ZT in a material system Nb0.95M0.05FeSb (M = Hf, Zr, Ti). It is found that Hf dopant is capable to simultaneously supply carriers for mobility optimization and introduce atomic disorder for reducing lattice thermal conductivity. As a result, Nb0.95Hf0.05FeSb distinguishes itself from other outstanding NbFeSb‐based materials in both the PF and ZT. Additionally, a large output power density of ≈21.6 W cm−2 is achieved based on a single‐leg device under a temperature difference of ≈560 K, showing the realistic prospect of the ultrahigh PF for power generation.

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Section: Introductionmentioning

confidence: 99%

Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)

Ren

Zhu

et al. 2018

Advanced Science

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“…In particular, the dense dislocation arrays formed at low-energy GBs from liquid-phase compaction in bismuth telluride based TE materials has been demonstrated to dramatically decrease the thermal conductivity resulting in a dramatically improved zT of 1.86 at 320 K [25]. This GB strategy has been further applied in other TE semiconductors such as PbTe, Mg 2 Si, and CoSb 3 for enhancing their zT values [26][27][28]. In addition, nanotwinned bismuth telluride also can promote superior TE performance and robust mechanical properties [29], which further suggest that nanoscale twins may play an essential role in the mechanical properties of TE semiconductors.…”

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confidence: 99%

“…In addition, nanotwins in ceramics have been found to dramatically enhance the hardness of diamond and boron nitride [23,24]. However, the influence of nanotwins on the mechanical properties of TE semiconductors remains largely unexplored.Very recently, a GBs' engineering strategy was proposed to reduce the lattice thermal conductivity and thereby significantly enhance the zT value of TE semiconductors [25][26][27][28]. In particular, the dense dislocation arrays formed at low-energy GBs from liquid-phase compaction in bismuth telluride based TE materials has been demonstrated to dramatically decrease the thermal conductivity…”

mentioning

confidence: 99%

“…Very recently, a GBs' engineering strategy was proposed to reduce the lattice thermal conductivity and thereby significantly enhance the zT value of TE semiconductors [25][26][27][28]. In particular, the dense dislocation arrays formed at low-energy GBs from liquid-phase compaction in bismuth telluride based TE materials has been demonstrated to dramatically decrease the thermal conductivity…”

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confidence: 99%

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Superstrengthening Bi2Te3 through Nanotwinning

Aydemir

Morozov

et al. 2017

Phys. Rev. Lett.

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Bismuth telluride (Bi 2 Te 3 ) based thermoelectric (TE) materials have been commercialized successfully as solid-state power generators, but their low mechanical strength suggests that these materials may not be reliable for long-term use in TE devices. Here we use density functional theory to show that the ideal shear strength of Bi 2 Te 3 can be significantly enhanced up to 215% by imposing nanoscale twins. We reveal that the origin of the low strength in single crystalline Bi 2 Te 3 is the weak van der Waals interaction between the Te1 coupling two Te1─Bi─Te2─Bi─Te1 five-layer quint substructures. However, we demonstrate here a surprising result that forming twin boundaries between the Te1 atoms of adjacent quints greatly strengthens the interaction between them, leading to a tripling of the ideal shear strength in nanotwinned Bi 2 Te 3 (0.6 GPa) compared to that in the single crystalline material (0.19 GPa). This grain boundary engineering strategy opens a new pathway for designing robust Bi 2 Te 3 TE semiconductors for high-performance TE devices. DOI: 10.1103/PhysRevLett.119.085501 The continued use of fossil fuels to satisfy escalating global energy requirements is causing severe unacceptable environmental impact. This has generated renewed interest in thermoelectric (TE) conversion technology to convert waste heat directly into electricity, which involves no CO 2 production, is scalable to large power plants, and involves no moving parts (silent) [1]. Over the past two decades, the conversion efficiency (zT) of TE materials has enhanced remarkably, approaching to ∼1.8 [2-4], putting TE materials on the threshold of commercial applications. However, under severe operation conditions, TE materials suffer from unavoidable thermomechanical stresses from cycling of the temperature gradients, leading to rapid deterioration of material performance and accelerated failure of TE devices [5][6][7]. In order for thermoelectrics to play a significant role in engineering applications to alternative energy, the strength and the toughness must be dramatically enhanced.Industrial low temperature waste heat accounts for almost one-third of total energy consumption [8]. The bismuth telluride (Bi 2 Te 3 ) state-of-the-art TE material has been widely used for TE refrigeration in this temperature range (300-550 K) [9], and is now being considered in the automotive industry for recovering waste heat from exhaust systems. Traditional elemental doping strategies have been successful in significantly improving TE properties [10,11], but they have had little effect on enhancing the mechanical properties [12]. Recently, nano-SiC particles dispersed in Bi 2 Te 3 were reported to enhance mechanical strength compared to pure Bi 2 Te 3 , but with concomitant deterioration of the electronic transport properties [13].A well-known mechanism for strengthening metal alloys is to increase the number of such interfacial boundaries as grain boundaries (GBs) and twin boundaries (TBs). These boundaries can strengthen the material by pinning...

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“…This led to most of the research efforts in TE being focused on minimizing the lattice thermal conductivity, which is the only independent material parameter. Effective approaches include nanostructuring, 2-7 lattice anharmonicity, 8,9 liquid phonons, 10,11 vacancy [12][13][14] or interstitial 15 point defects and a low sound velocity. 16 Band engineering concepts including a large number of degenerated bands, [17][18][19][20][21][22][23][24][25] a low band effective mass 26 and weak carrier scattering 27 have also proven to be successful in enhancing the TE performance.…”

Section: Introductionmentioning

confidence: 99%

Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides

et al. 2017

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PbTe and SnTe in their p-type forms have long been considered high-performance thermoelectrics, and both of them largely rely on two valence bands (the first band at L point and the second one along the Σ line) participating in the transport properties. This work focuses on the thermoelectric transport properties inherent to p-type GeTe, a member of the group IV monotellurides that is relatively less studied. Approximately 50 GeTe samples have been synthesized with different carrier concentrations spanning from 1 to 20 × 10 20 cm − 3 , enabling an insightful understanding of the electronic transport and a full carrier concentration optimization for the thermoelectric performance. When all of these three monotellurides (PbTe, SnTe and GeTe) are fully optimized in their p-type forms, GeTe shows the highest thermoelectric figure of merit (zT up to 1.8). This is due to its superior electronic performance, originating from the highly degenerated Σ band at the band edge in the low-temperature rhombohedral phase and the smallest effective masses for both the L and Σ bands in the high-temperature cubic phase. The high thermoelectric performance of GeTe that is induced by its unique electronic structure not only provides a reference substance for understanding existing research on GeTe but also opens new possibilities for the further improvement of the thermoelectric performance of this material.

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Vacancy-induced dislocations within grains for high-performance PbSe thermoelectrics

Cited by 395 publications

References 62 publications

Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)

Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)

Superstrengthening Bi2Te3 through Nanotwinning

Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides

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Vacancy-induced dislocations within grains for high-performance PbSe thermoelectrics

Cited by 395 publications

References 62 publications

Ultrahigh Power Factor in Thermoelectric System Nb0.95M0.05FeSb (M = Hf, Zr, and Ti)

Ultrahigh Power Factor in Thermoelectric System Nb0.95M0.05FeSb (M = Hf, Zr, and Ti)

Superstrengthening Bi2Te3 through Nanotwinning

Electronic origin of the high thermoelectric performance of GeTe among the p-type group IV monotellurides

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Product

Resources

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Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)

Ultrahigh Power Factor in Thermoelectric System Nb_0.95M_0.05FeSb (M = Hf, Zr, and Ti)