Tuning the Thermoelectric Performance of Benzo-difuran Molecular Wires
Using a first principles approach to electron transport, we calculate the electrical and thermoelectrical transport properties of a series of molecular wires containing benzo-difuran subunits. The presence of side groups in these structures introduces Fano resonances into the transport properties, which are not present in the more widely studied oligophenylene ethynylene and oligophenylene vinylene (OPE, OPV) molecules. We demonstrate that the energies of Fano resonances can be tuned by varying the electronegativity of selected atoms. We also study the relative effect of single, double or triple bonds along the molecular backbone and find that single bonds yield the highest thermopower, which at room temperature is approximately 22µV/K, which is comparable with the highest measured values for single-molecule thermopower reported to date.