Substrate reconstruction mediated unidirectionally aligned molecular dipole dot arrays

We report the fabrication of unidirectionally aligned molecular dipole dot arrays of vanadyl phthalocyanine (VOPc) on Au(111). Low-temperature scanning tunneling microscopy (LT-STM) studies reveal that isolated VOPc molecules adsorb predominantly at the elbow sites of the 22 × √3 herringbone reconstructed Au(111) surface, and adopt an O-down configuration with the phthalocyanine plane parallel to the substrate. It is proposed that the low-coordinated Au atom at the elbow sites on the reconstructed Au(111) can interact strongly with the O-down oriented VOPc molecule, and hence leads to the formation of the unidirectionally aligned VOPc molecular dipole dot arrays.