Interference enhanced thermoelectricity in quinoid type structures
arXiv:1507.00179 · doi:10.1063/1.4913290
Abstract
Quantum interference (QI) effects in molecular junctions may be used to obtain large thermoelectric responses. We study the electrical conductance G and the thermoelec- tric response of a series of molecules featuring a quinoid core using density functional theory (DFT), as well as a semi-empirical interacting model Hamiltonian describing the π-system of the molecule which we treat in the GW approximation. Molecules with a quinoid type structure are shown to have two distinct destructive QI features close to the frontier orbital energies. These manifest themselves as two dips in the transmission, that remain separated, even when either electron donating or withdraw- ing side groups are added. We find that the position of the dips in the transmission and the frontier molecular levels can be chemically controlled by varying the electron donating or withdrawing character of the side groups as well as the conjugation length inside the molecule. This feature results in a very high thermoelectric power factor S^2G and figure of merit ZT, where S is the Seebeck coefficient, making quinoid type molecules potential candidates for efficient thermoelectric devices.
22 pages, 11 figures
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Cited by in corpus (7)
- Advances and challenges in single-molecule electron transport
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- Green's function methods for single molecule junctions
- Destructive quantum interference in electron transport: A reconciliation of the molecular orbital and the atomic orbital perspective
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- Electrode effects on the observability of destructive quantum interference in single-molecule junctions
- Electronic and Thermoelectric Properties of Molecular Junctions Incorporating Organometallic Complexes: Implications for Thermoelectric Energy Conversion