Modeling of thermoelectric properties of n – type organic crystals of TTT(TCNQ)2: 3D physical model

Sanduleac, I. and Casian, A. (2015) Modeling of thermoelectric properties of n – type organic crystals of TTT(TCNQ)2: 3D physical model. Journal of Electronic Materials . ISSN 1543-186X

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Abstract

Thermoelectric properties of quasi-one-dimensional TTT(TCNQ)2 organic crystals are investigated in order to appreciate the prospect of using this compound as n–type thermoelectric material. A more complete three-dimensional (3D) physical model is elaborated. It takes into account two the most important interactions of conduction electrons with longitudinal acoustic phonons, the electrons’ scattering on neighbor molecular chains, as well as the scattering by impurities and defects. The electrical conductivity, thermopower, the power factor, electronic thermal conductivity and the thermoelectric figure of merit in the direction along conductive molecular chains are calculated numerically for different degrees of crystal purity. It is shown that in stoichiometric compounds the thermoelectric figure of merit ZT remains small even after the increase of crystal perfection degree. The thermoelectric properties may be significantly enhanced by simultaneous increase of crystal perfection and of electron concentration. The latter can be achieved by additional doping with donors. For less pure crystals, the interaction with impurities predominates over the weak interchain interaction and the simpler one-dimensional (1D) physical model is applicable. When the impurity scattering is reduced, the interchain interaction begins to limit the carrier mobility and the application of the 3D physical model is required. The optimal parameters permitting to predict ZT~ 1 are determined.

Item Type: Article
Additional Information: A paper produced for the H2ESOT project, a collaborative FP7 funded project led by Professor Simon Woodward from University of Nottingham and supported under the EU ENERGY Theme for Future Emerging Technologies. (c) 2015 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.
Keywords: TTT(TCNQ)2, electrical conductivity, Seebeck coefficient, power factor, thermal conductivity, thermoelectric figure of merit
Schools/Departments: University of Nottingham UK Campus > Faculty of Science > School of Chemistry
Identification Number: https://doi.org/10.1007/s11664-015-4018-8
Depositing User: Woodward, Prof Simon
Date Deposited: 18 Jan 2016 10:40
Last Modified: 22 Sep 2016 20:49
URI: http://eprints.nottingham.ac.uk/id/eprint/31269

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