title: Electrostatic-field-driven alignment of organic oligomers on ZnO surfaces.
abstract: We study the physisorption of organic oligomers on the strongly ionic ZnO(1010) surface by using first-principles density-functional theory and nonempirical embedding methods. It turns out that the in-plane variation of the molecule-substrate interaction energy and the bonding dipole in the vertical direction are linked up by a linear relationship originating from the electrostatic coupling of the molecule with the periodic dipolar electric field generated by the Zn-O surface dimers. Long oligomers with a highly axial π-electron system such as sexiphenyl become well oriented with alignment energies of several 100 meV along rows of a positive electric field, in full agreement with recent experiments. These findings define a new route towards the realization of highly ordered self-assembled arrays of oligomers or polymers on ZnO(1010) and similar surfaces.
authors: National Nanotechnology Laboratory, Istituto Nanoscienze-CNR, Via per Arnesano, I-73100 Lecce, Italy.
authors: F
authors: F
authors: Della Sala
authors: S
authors: S
authors: Blumstengel
authors: F
authors: F
authors: Henneberger