Reducing the molecule-substrate coupling in C60-based nanostructures by molecular interactions

Codeposition of C60 and the three-dimensional molecular hydrocarbon 1,3,5,7-tetraphenyladamantane (TPA) on Au(111) leads to the spontaneous formation of molecular nanostructures in which each fullerene is locked into a specific orientation by three surrounding TPA. Scanning tunneling spectroscopy shows that the electronic coupling of C60 with the surface is significantly reduced in these nanostructures, enhancing the free-molecule properties. As evidenced by density functional theory simulations, the nanostructures are stabilized by 18 local electrostatic forces between C60 and TPA, resulting in a lifting of the C60 cage from the surface.