Modulation of thermoelectric performance of Cn-BTBT molecular junctions by engineering contact geometry

Bei Zhang; Xiaojiao Zhang; Shidong Zhang; Yun-Peng Wang; Jiwei Dong; Yaoxing Sun; Fangping Ouyang; Mengqiu Long

Results in Physics (Jul 2021)

Modulation of thermoelectric performance of Cn-BTBT molecular junctions by engineering contact geometry

Bei Zhang,
Xiaojiao Zhang,
Shidong Zhang,
Yun-Peng Wang,
Jiwei Dong,
Yaoxing Sun,
Fangping Ouyang,
Mengqiu Long

Affiliations

Bei Zhang: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China; Xinjiang Key Laboratory of Solid State Physics and Device, School of Physical Science and Technology, Xinjiang University, Urumqi 830046, China
Xiaojiao Zhang: Department of Physics, School of Mathematics and Statistics, Hunan University of Technology and Business, Changsha 410205, China; Corresponding authors at: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China (M. Long).
Shidong Zhang: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China
Yun-Peng Wang: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China
Jiwei Dong: Xinjiang Key Laboratory of Solid State Physics and Device, School of Physical Science and Technology, Xinjiang University, Urumqi 830046, China
Yaoxing Sun: Xinjiang Key Laboratory of Solid State Physics and Device, School of Physical Science and Technology, Xinjiang University, Urumqi 830046, China
Fangping Ouyang: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China
Mengqiu Long: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China; Xinjiang Key Laboratory of Solid State Physics and Device, School of Physical Science and Technology, Xinjiang University, Urumqi 830046, China; Corresponding authors at: Hunan Key Laboratory of Super Micro-structure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha 410083, China (M. Long).

Journal volume & issue: Vol. 26
p. 104318

Abstract

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Organic molecular devices are promising candidates for thermoelectric applications. By using density functional theory combined with non-equilibrium Green’s function method, we have investigated the thermoelectric properties of a single-molecule junction, which is constructed by 2,7-dialkyl [1] benzothieno [3,2-b] [1] benzothiophene derivatives (Cn-BTBT) connected with zigzag graphene nanoribbon electrodes. It is found that the phonon thermal conductance decreases with the increase of alkyl edge branches due to the local resonance. And the thermoelectric performance can be enhanced significantly by substituting bithiophene or biphosphole bridge anchor groups. A good thermoelectric figure of merit about 0.56 can be obtained near Fermi level. Moreover, we also found that the molecular device can be changed from p-type into n-type by changing the contact points, resulting in the transformation of Seebeck coefficient from positive to negative.

Published in Results in Physics

ISSN: 2211-3797 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Science: Physics
Website: http://www.journals.elsevier.com/results-in-physics/

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