The effect of geometric arrangement on the thermoelectric properties of Phenanthrene coupled to the graphene nanoribbons electrodes

摘要

The thermoelectric properties of a Phenanthrene molecule, such as thermopower, electrical conductivity, thermal conductivity and figure of merit, are investigated by applying the non-equilibrium Green's function (NEGF) method combined with the density functional theory (DFT). Phenanthrene is intended to couple to the graphene nanoribbons electrodes in two configurations. The vertical and horizontal orientations of the molecule between the nanoribbons are considered. The results reveal that the thermoelectric properties of the considered structures are dependent on the orientation of Phenanthrene configuration between the electrodes. At high chemical potential, the greatest figure of merit is observed for Phenanthrene, which is vertically attached to the electrodes, because of the small thermal conductivity of this configuration. On the other hand, the symmetric and horizontal configurations of the molecule make it a high-performance thermoelectric device at zero chemical potential.