Localized vibration and avoided crossing in SrTi<sub>11</sub>O<sub>20</sub> for oxide thermoelectrics with intrinsically low thermal conductivity

Li, Yi; Yamamoto, Shinya; Ahmad, Kamsuriah; Almutairi, Zeyad; Koumoto, Kunihito; Wan, Chunlei

doi:10.1039/d1ta01920a

Cited by 13 publications

(4 citation statements)

References 58 publications

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“…67 To address this issue, a novel thermoelectric oxide SrTi O 20 is presented, where the TiO 6 octahedra form a network creating an irregular polyhedron for the loosely bonded Sr ions and thus obtain an extremally low κ lat ∼1.7 W m −1 K −1 even comparable with PbTe. 89 Very recently, Light element H − substitution in SrTiO 2.784 H 0.216 largely reduces its κ lat to 3.5 W m −1 K −1 . 80 Importantly, the given Sr−H bonding energy is 164 kJ mol much lower than Sr−O bond even PbTe, 67 which implies that selective introduction of lowenergy bonds by reference to the chemical bond energy is an effective way to weakened the bond and thus inhibit κ lat .…”

Section: Weakened Bondmentioning

confidence: 99%

“…Note that the SrTiO 3 shows a high κ lat ∼9 W m −1 K −1 at 300 K because of the high bonding energy 426.3 kJ mol of Sr−O bond 67 . To address this issue, a novel thermoelectric oxide SrTi 11 O 20 is presented, where the TiO 6 octahedra form a network creating an irregular polyhedron for the loosely bonded Sr ions and thus obtain an extremally low κ lat ∼1.7 W m −1 K −1 even comparable with PbTe 89 . Very recently, Light element H − substitution in SrTiO 2.784 H 0.216 largely reduces its κ lat to 3.5 W m −1 K −1 80 .…”

Section: Lattice Thermal Conductivity Suppression Strategiesmentioning

confidence: 99%

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Oxide semiconductors for thermoelectric: The challenges and future

Ge,

Li,

Wang

et al. 2023

J Am Ceram Soc.

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The oxide thermoelectric (TE) ceramics have continued to attract the focus due to their high stability and low cost. However, their TE performance falls obviously backward with the typical TE compounds such as PbTe. Here, we revealed the reason for the difficulty of optimized performance is the large electronegativity difference between the metal and O ions in oxide, which results in strong electron localization and bond energy. The former leads to unfavorable electrical properties and the latter results in a high lattice thermal conductivity. Focusing on these issues, we briefly reviewed the strategies for electrical optimization including carrier concentration optimization, band gap tuning, and the density of state resonance, as well as the lattice thermal suppression strategies involving weakened bond, high entropy, grain size engineering, hierarchical architecture, textured polycrystal, and composite strategies for oxide TE ceramics. Finally, we proposed several possible perspectives for n‐type oxide TE ceramics, strategies for bond anisotropy, and predicted new TE oxides for further breakthroughs in oxide TE properties.

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Section: Weakened Bondmentioning

confidence: 99%

Section: Lattice Thermal Conductivity Suppression Strategiesmentioning

confidence: 99%

Oxide semiconductors for thermoelectric: The challenges and future

Ge,

Li,

Wang

et al. 2023

J Am Ceram Soc.

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“…In Figure 4, we visualized such a low-frequency molecular optical modes by red arrows: the first two modes involve specific rotations of the butyl groups, and the third involves the rotation of the whole tert-butyl isocyanate molecule. The phonon-crossing phenomenon, identified in various structures, [30][31][32] are usually correlated with a noteworthy decrease in acoustic phonon group velocities and a corresponding strong increases of the vibrational anharmonicity, ultimately resulting in a further decrease of thermal conductivity. [33] Figure 5 shows the corresponding group velocities of the acoustic (and quasi-acoustic for structure (a)) phonon modes (see Figure 5).…”

Section: Systemmentioning

confidence: 99%

An Ab Initio Investigation of Ultra‐Low Thermal Conductivity in Organically Functionalized TaS2${\rm TaS}_2$

Siddi,

Cappai,

Colombo

et al. 2024

Advcd Theory and Sims

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An ab initio characterization of the impact of tert‐Butyl isocyanate () functionalization on lattice thermal conductivity is presented. Such a system has been previously synthetized and experimentally charachterized, showing that the incorporation of covalently bonded on bulk leads to a dramatic in‐plane lattice thermal conductivity decrease by more than two orders of magnitudes. To elucidate these experimental findings, detailed calculations of the phonon dispersion relations and scattering rates in are performed. The analysis is addressed to discern the impact of inter‐layer covalently bonded molecules on these phonon properties, providing insights into the underlying mechanisms of the observed thermal conductivity decrease. Present calculations provide evidence that the observed lattice thermal conductivity reduction is attributed to two effects: the increase of inter‐layer separation and the presence of low‐frequency molecular optical modes. The first inhibits specific Van der Waals quasi‐acoustic inter‐layer vibrational modes contributing as much as in bulk . The second effect dramatically decreases the phonon group velocities as a consequence of phonon‐crossing phenomena among low‐frequency molecular modes and acoustic modes, eventually leading to a strong reduction of all phonon lifetimes.

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“…The mixing phenomenon between acoustic and optical phonons introduced anharmonicity effects in the crystal structure. This mechanism caused the flattening of the phonon modes and suppression of acoustic group velocity [364]. You et al observed the dynamic behavior of Cu-ion doped in the PbSe matrix, providing more charge carriers with the increasing temperature.…”

Section: Phonon Engineeringmentioning

confidence: 99%

Physics and technology of thermoelectric materials and devices

Dadhich

Saminathan

Kumari

et al. 2023

J. Phys. D: Appl. Phys.

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The continuous depletion of fossil fuels and the increasing demand for eco-friendly and sustainable energy sources have prompted researchers to look for alternative energy sources. The loss of thermal energy in heat engines (100-350 ºC), coal-based thermal plants (150-700 ºC), heated water pumping in the geothermal process (150-700 ºC), and burning of petrol in the automobiles (150-250 ºC) in form of untapped waste-heat can be directly and/or reversibly converted into usable electricity by means of charge carriers (electrons or holes) as moving fluids using thermoelectric (TE) technology, which works based on typical Seebeck effect. The enhancement in TE conversion efficiency has been a key challenge because of the coupled relation between thermal and electrical transport of charge carriers in a given material. In this review, we have deliberated the physical concepts governing the materials to device performance as well as key challenges for enhancing the TE performance. Moreover, the role of crystal structure in the form of chemical bonding, crystal symmetry, order-disorder and phase transition on charge carrier transport in the material has been explored. Further, this review has also emphasized some insights on various approaches employed recently to improve the TE performance, such as, (i). carrier engineering via band engineering, low dimensional effects, and energy filtering effects and (ii). Phonon engineering via doping/alloying, nano-structuring, embedding secondary phases in the matrix and microstructural engineering. Wehave also briefed the importance of magnetic elements on thermoelectric properties of the selected materials and spin Seebeck effect. Furthermore, the design and fabrication of TE modules and their major challenges are also discussed. As, thermoelectric figure of merit, zT does not have any theoretical limitation, an ideal high performance thermoelectric device should consist of low-cost, eco-friendly, efficient, n- or p-type materials that operate at wide- temperature range and similar coefficients of thermal expansion, suitable contact materials, less electrical/ thermal losses and constant source of thermal energy. Overall, this review provides the recent physical concepts adopted and fabrication procedures of TE materials and device so as to improve the fundamental understanding and to develop a promising TE device.

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Localized vibration and avoided crossing in SrTi₁₁O₂₀ for oxide thermoelectrics with intrinsically low thermal conductivity

Abstract: The localized vibration in SrTi11O20 forms low-lying optical phonon bands that distort acoustic phonon branches through the avoided crossing effect. The electrical and thermal transport are decoupled to achieve phonon-glass electron-crystal behaviour.

Cited by 13 publications

References 58 publications

Oxide semiconductors for thermoelectric: The challenges and future

Oxide semiconductors for thermoelectric: The challenges and future

An Ab Initio Investigation of Ultra‐Low Thermal Conductivity in Organically Functionalized TaS2${\rm TaS}_2$

Physics and technology of thermoelectric materials and devices

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Localized vibration and avoided crossing in SrTi11O20 for oxide thermoelectrics with intrinsically low thermal conductivity

Abstract: The localized vibration in SrTi11O20 forms low-lying optical phonon bands that distort acoustic phonon branches through the avoided crossing effect. The electrical and thermal transport are decoupled to achieve phonon-glass electron-crystal behaviour.

Cited by 13 publications

References 58 publications

Oxide semiconductors for thermoelectric: The challenges and future

Oxide semiconductors for thermoelectric: The challenges and future

An Ab Initio Investigation of Ultra‐Low Thermal Conductivity in Organically Functionalized TaS2${\rm TaS}_2$

Physics and technology of thermoelectric materials and devices

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Product

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Localized vibration and avoided crossing in SrTi₁₁O₂₀ for oxide thermoelectrics with intrinsically low thermal conductivity