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Possible Charge Density Wave and Enhancement of Thermoelectric Properties at Mild-Temperature Range in n-Type Cul-Doped Bi2Te2.1Se0.9 Compounds

Title
Possible Charge Density Wave and Enhancement of Thermoelectric Properties at Mild-Temperature Range in n-Type Cul-Doped Bi2Te2.1Se0.9 Compounds
Authors
Cho, HyunyongYun, Jae HyunKim, Jin HeeBack, Song YiLee, Ho SeongKim, Sung JinByeon, SeokyeongJin, HyungyuRhyee, Jong-Soo
Ewha Authors
김성진
SCOPUS Author ID
김성진scopus
Issue Date
2020
Journal Title
ACS APPLIED MATERIALS & INTERFACES
ISSN
1944-8244JCR Link

1944-8252JCR Link
Citation
ACS APPLIED MATERIALS & INTERFACES vol. 12, no. 1, pp. 925 - 933
Keywords
Bi2Te3codopingthermoelectriccharge density wavelattice modulationphase transition
Publisher
AMER CHEMICAL SOC
Indexed
SCI; SCIE; SCOPUS WOS scopus
Document Type
Article
Abstract
Bi2Te3-based compounds have long been studied as thermoelectric materials in cooling applications near room temperature. Here, we investigated the thermoelectric properties of CuI-doped Bi2Te2.1Se0.9 compounds. The Cu/I codoping induces the lattice distortion partially in the matrix. We report that the charge density wave caused by the local lattice distortion affects the electrical and thermal transport properties. From the high-temperature specific heat, we found a first-order phase transitions near 490 and 575 K for CuI-doped compounds (CuI)(x)Bi2Te2.1Se0.9 (x = 0.3 and 0.6%), respectively. It is not a structural phase transition, confirming from the high-temperature X-ray diffraction. The temperature-dependent electrical resistivity shows a typical behavior of charge density wave transition, which is consistent with the temperature-dependent Seebeck coefficient and thermal conductivity. The transmission electron microscopy and electron diffraction show a local lattice distortion, driven by the charge density wave transition. The charge density wave formation in the Bi2Te3-based compounds are exceptional because of the possibility of coexistence of charge density wave and topological surface states. From the Kubo formula and Boltzmann transport calculations, the formation of charge density wave enhances the power factor. The lattice modulation and charge density wave decrease lattice thermal conductivity, resulting in the enhancement of thermoelectric performance simultaneously in CuI-doped samples. Consequently, an enhancement of thermoelectric performance ZT over 1.0 is achieved at 448 K in the (CuI)(0.003)Bi(2)Te(2)ASe(0.9) sample. The enhancement of ZT at high temperature gives rise to a superior average ZT(avg) (1.0) value than those of previously reported ones.
DOI
10.1021/acsami.9b19398
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자연과학대학 > 화학·나노과학전공 > Journal papers
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