Nanostructured chiral surfaces

Chiral organic surfaces were generated via adsorption of the pure enantiomers of heptahelicene, a helically shaped aromatic hydrocarbon, on a Ni(III) surface in ultra high vacuum. Time-of-flight secondary mass spectrometry (ToF-SIMS) revealed that the molecule stays intact at room temperature. The formation of a two-dimensionally ordered structure at monolayer coverage is observed via low-energy electron diffraction (LEED) and scanning tunnelling spectroscopy (STM). For creation of a chiral metal film, the chiral organic monolayer was subjected to subsequent metal physical vapour deposition. Differences in morphology of grown copper and palladium films were only observed when heptahelicene was adsorbed prior to deposition. No screw dislocations with preferred handedness were observed when the pure enantiomers were used.