Highly ordered C₆₀ monolayer self-assembled by using an iodine template on an Au(111) surface in solution

An iodine-modified Au(111) surface, (I/Au(111)), was used as a substrate to prepare a C₆₀ adlayer by self-organization in a benzene solution. A highly ordered C₆₀ adlayer was successfully prepared due to the moderate C₆₀-I/Au(111) interaction. Two lattice structures, (2√3 × 2√3)R30° and p(2 × 2), were imaged for this C₆₀ adlayer. For the first structure, a featureless ball-like molecular shape was imaged, ascribed to the molecular rotation resulting from a symmetrical location between C₆₀ and iodine atoms. For p(2 × 2) structure, the asymmetrical location of C₆₀ with respect to the iodine atoms freezes the C₆₀ molecules on the substrate, leading to a clear image of intramolecular structure. The intermediate iodine atoms in the C₆₀/I/Au(111) adlayer can be desorbed by electrochemically reduction without significantly affecting the ordering of the C₆₀ adlayer. However, the internal pattern of C₆₀ disappears in the absence of iodine.