Electrical and thermal transport properties of layered Bi2YO4Cu2Se2

Xiao, Yu; Pei, Yanling; Chang, Cheng; Zhang, Xiao; Tan, Xuezhi; Ye, Xinxin; Gong, Shengkai; Lin, Yuanhua; He, Jiaqing; Zhao, Li‐Dong

doi:10.1016/j.jssc.2016.03.032

Cited by 11 publications

(16 citation statements)

References 25 publications

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“…Based on the measured acoustic velocities, we can estimate the Young' modulus (E), Grüneisen parameter (g) and Debye temperature (q D ), which are the key parameters to revealing a crystalline material's lattice thermal conductivity. 37,38 As shown in Table 1, the measured longitudinal and transverse sound velocities are 2358 ms À1 and 1447 ms À1 , respectively, which are consistent with reported 2285 ms À1 and 1410 ms À1 . 36 As a result, we obtain relatively low average sound velocities and Young's modulus, 1597 ms À1 and 31.3 GPa in horizontal direction, 1494 ms À1 and 27.7 GPa in vertical direction of the sample.…”

Section: Resultssupporting

confidence: 87%

Effective dopants in p-type elementary Te thermoelectrics

et al. 2017

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Section: Resultssupporting

confidence: 87%

Effective dopants in p-type elementary Te thermoelectrics

et al. 2017

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“…The value of ∼126 K for K 2.5 Bi 8.5 Se 14 was obtained using the formula, , where h , k B , N , V , and v a are Planck’s constant, Boltzmann constant, number of atoms in a unit cell, unit cell volume, and average phonon velocity, respectively. This result is lower than that of other Bi-chalcogenide-based thermoelectric materials (e.g., 154 K for K 2 Bi 8 Se 13 with ∼30% second-phase K 2.5 Bi 8.5 Se 14 , 243 K for BiCuSeO, and 280 K Bi 2 YO 4 Cu 2 Se 2 ), consistent with the low-average phonon velocity (1610 m s –1 ) and thermal conductivity of K 2.5 Bi 8.5 Se 14 .…”

Section: Resultssupporting

confidence: 63%

“…The Young’s modulus of 35.8 GPa for K 2.5 Bi 8.5 Se 14 is lower than those of other Bi-chalcogenide-based thermoelectric materials (e.g., 37.1 GPa for K 2 Bi 8 Se 13, 76.5 GPa for BiCuSeO, and 70.6 GPa for Bi 2 YO 4 Cu 2 Se 2 ). Also, the small Young’s modulus leads to a low-average phonon velocity of 1610 m s –1 for K 2.5 Bi 8.5 Se 14 .…”

Section: Resultsmentioning

confidence: 76%

“…The Grüneisen parameter (γ), a measure of the lattice anharmonicity, is another means of understanding the thermal conductivity . The experimental Grüneisen parameter value of ∼1.96 for K 2.5 Bi 8.5 Se 14 is larger than those of other Bi-chalcogenide-based thermoelectric materials (e.g., 1.71 for K 2 Bi 8 Se 13, 1.5 for BiCuSeO, and 1.71 for Bi 2 YO 4 Cu 2 Se 2 ). The higher value suggests a larger anharmonicity in K 2.5 Bi 8.5 Se 14 .…”

Section: Resultsmentioning

confidence: 99%

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Ultralow Thermal Conductivity and High-Temperature Thermoelectric Performance in n-Type K_2.5Bi_8.5Se₁₄

Luo

Cai²,

Hao³

et al. 2019

Chem. Mater.

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We studied the narrow band-gap (0.55 eV) semiconductor K 2.5 Bi 8.5 Se 14 as a potential thermoelectric material for power generation. Samples of polycrystalline K 2.5 Bi 8.5 Se 14 prepared by spark plasma sintering exhibit exceptionally low lattice thermal conductivities (κ lat ) of 0.57−0.33 W m −1 K −1 in the temperature range of 300−873 K. The physical origin of such low κ lat in K 2.5 Bi 8.5 Se 14 is related to the strong anharmonicity and low phonon velocity caused by its complex low symmetry, large unit cell crystal structure, and mixed occupancy of Bi and K atoms in the lattice. High-resolution scanning transmission electron microscopy studies and microanalysis indicate that the K 2.5 Bi 8.5 Se 14 sample is a single phase without intergrowth of the structurally related K 2 Bi 8 Se 13 phase. The undoped material exhibits an n-type character and a figure-of-merit (ZT) value of 0.67 at 873 K. Electronic band structure calculations indicate that K 2.5 Bi 8.5 Se 14 is an indirect band-gap semiconductor with multiple conduction bands close to the Fermi level. Phonon dispersion calculations suggest that K 2.5 Bi 8.5 Se 14 has low phonon velocities and large Gruneisen parameters that can account for the observed ultralow κ lat . The degree of n-type doping can be controlled by introducing Se deficiencies in the structure, providing a simple route to increase the ZT to ∼1 at 873 K.

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“…The ZT figure shows an increasing trend with temperature and a maximum ZT of ≈0.27 at 923K is achieved in Bi 2 DyO 4 Cu 2 Se 2 , 4 times higher than that of Bi 2 YO 4 Cu 2 Se 2 . [ 47 ] However, it is hard to compare the ZT values of in‐plane and out‐of‐plane directions, because better electrical properties perform in the in‐plane direction while the lower thermal conductivity possesses in the out‐of‐plane direction (Figure S4d–f, Supporting Information). To sum up, we developed a facile and fast method of preparing most of Bi 2 LnO 4 Cu 2 Se 2 phase, which may be suited for other layered oxyselenides.…”

Section: Resultsmentioning

confidence: 99%

Seeking New Layered Oxyselenides with Promising Thermoelectric Performance

Yang

Han

Zhou

et al. 2022

Adv Funct Materials

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Layered oxyselenides have been widely investigated as promising thermoelectric materials due to their unique merits such as super‐lattice structural features and intrinsic complexity, which contributes to low thermal conductivity and easily controllable electrical properties. Newly developed Bi2LnO4Cu2Se2 (Ln stands for lanthanide) oxyselenides are found to be potential thermoelectric systems since they have excellent electrical conductivity over 103 S cm−1. In this work, unique energy and time‐saving method combined self‐propagating high‐temperature synthesis (SHS) with spark plasma sintering (SPS) is adopted to successfully prepare a highly pure Bi2LnO4Cu2Se2 instead of a traditional solid‐state reaction. To explore the most suitable lanthanide for Bi2LnO4Cu2Se2, thermoelectric performance in a wide temperature range (300 to 923 K) of Bi2LnO4Cu2Se2 (Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er) is deeply evaluated and studied. Ultimately, with a relatively high electrical conductivity, moderate Seebeck coefficient, and extremely low thermal conductivity, a maximum ZT value of ≈0.27 at 923K is achieved in Bi2DyO4Cu2Se2, which is 4 times larger than that of the ever‐reported Bi2YO4Cu2Se2 and proves a potential thermoelectric system for further investigation. This work may provide some enlightenment and broaden the horizon in finding new thermoelectric materials, especially for complex layered compounds.

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Electrical and thermal transport properties of layered Bi2YO4Cu2Se2

Cited by 11 publications

References 25 publications

Effective dopants in p-type elementary Te thermoelectrics

Effective dopants in p-type elementary Te thermoelectrics

Ultralow Thermal Conductivity and High-Temperature Thermoelectric Performance in n-Type K_2.5Bi_8.5Se₁₄

Seeking New Layered Oxyselenides with Promising Thermoelectric Performance

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Electrical and thermal transport properties of layered Bi2YO4Cu2Se2

Cited by 11 publications

References 25 publications

Effective dopants in p-type elementary Te thermoelectrics

Effective dopants in p-type elementary Te thermoelectrics

Ultralow Thermal Conductivity and High-Temperature Thermoelectric Performance in n-Type K2.5Bi8.5Se14

Seeking New Layered Oxyselenides with Promising Thermoelectric Performance

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Product

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Ultralow Thermal Conductivity and High-Temperature Thermoelectric Performance in n-Type K_2.5Bi_8.5Se₁₄