Authors: Ionel Sanduleac Anatolie Casian
Publish Date: 2015/09/08
Volume: 45, Issue: 3, Pages: 1316-1320
Abstract
The thermoelectric properties of quasionedimensional TTTTCNQ2 organic crystals have been investigated to assess the prospect of using this type of compound as an ntype thermoelectric material A threedimensional 3D physical model was elaborated This takes into account two of the most important interactions of conduction electrons with longitudinal acoustic phonons—scattering of the electrons’ by neighboring molecular chains and scattering by impurities and defects Electrical conductivity thermopower power factor electronic thermal conductivity and thermoelectric figure of merit in the direction along the conducting molecular chains were calculated numerically for different crystal purity It was shown that in stoichiometric compounds the thermoelectric figure of merit ZT remains small even after an increase of crystal perfection The thermoelectric properties may be significantly enhanced by simultaneous increases of crystal perfection and electron concentration The latter can be achieved by additional doping with donors For less pure crystals the interaction with impurities dominates the weak interchain interaction and the simpler onedimensional 1D physical model is applicable When the impurity scattering is reduced the interchain interaction begins to limit carrier mobility and use of the 3D physical model is required The optimum properties enabling prediction of ZT ∼ 1 were determined
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