  The thermoelectric properties of polythiophene (PT) coupled to the Au (111)
electrodes are studied based on density functional theory combined with
nonequilibrium Green function formalism. Specially, the effect of Li and Cl
adsorbents on the thermoelectric efficiency of the PT junction is investigated
in different concentrations of the dopants for two lengths of the PT. Results
show that the presence of dopants can bring the structural changes in the
oligomer and modify the arrangement of the molecular levels leading to the
dramatic changes in the transmission spectra of the junction. Therefore, the
large enhancement in thermopower and consequently figure of merit is obtained
by dopants which makes the doped PT junction as a beneficial thermoelectric
device.
