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Nanoscale structure–electric potential relations in films of the organic molecular semiconductors C60 and titanyl phthalocyanine (TiOPc) on Ag(111) have been measured under UHV conditions. Noncontact force methods were utilized to image domain structures and boundaries with molecular resolution, while simultaneously quantifying the local surface electric potential. Sensitivity and spatial resolution for the local potential measurement were first established on Ag(111) through direct observation of the electrical dipole and potential step, φstep = 10 ± 3 mV, of monatomic crystallographic steps. A local surface potential increase of 27 ± 11 mV occurs upon crossing the boundary between the neat Ag(111) surface and C60 islands. Potential steps in binary C60–TiOPc films, nanophase-separated into crystalline C60 and TiOPc domains, were then mapped quantitatively. The 207 ± 66 mV potential step across the C60-to-TiOPc domain boundary exhibits a 3.6 nm width that reflects the spatial resolution for electric poten...

We have demonstrated a method for fabricating C60 overlayers with controlled spacing and chirality by reactive coadsorption with the aromatic molecule acridine-9-carboxylic acid (ACA). Structural control is achieved by the mismatched symmetries of the coadsorbates, as well as specific intermolecular and adsorbate-substrate interactions. The resulting supramolecular structure has a C60 period nearly three times as large as the normal C60 2D packing of 1 nm and exists in enantiopure domains with robust chirality.