Structure Of Fullerene Films Research Articles

The structure of fullerene films and their metallocene doping

Hexagonal close-packed (HCP) C60 and C70 films have been prepared by the Langmuir method and examined by electron microscopy and electron-diffraction analysis. It has been shown that the vacuum deposition of a C60+C70 mixture results in the formation of a film with small sized grains and a distorted C60-HCP structure. The simultaneous deposition of C60 and ferrocene results in the formation of a film with a changed morphology and an electron-diffraction pattern that contains a variable amount of ferrocene depending on the experimental conditions. The electron-diffraction pattern corresponds to the presence of the known molecular complex C60[(C5H5)2Fe]2. The analogous simultaneous deposition of fullerene C60 and cobaltocene results in the formation of a C60 film stable in air and water, which contains carbon and cobalt (from the data of X-ray fluorescence, electron microscopy and microdiffraction). It has a different morphology and different diffraction patterns than pure C60 films and, depending on the cobaltocene content (relative to that of fullerene), appears to be a fullerite film doped with various amounts of cobaltocenium fullende, which is an ionic compound.

Nucleation, growth, and structure of fullerene films on Au(111)

The growth of fullerene films by vapor deposition on Au(111) was studied using UHV-STM, LEED, AES, and TOF-SIMS. The fullerenes were found to grow in a layer-by-layer manner. The molecules initially adsorb at intersections of multiple steps and edges of monatomic steps on narrow terraces. As the coverage is increased, periodic arrays of short chains form at steps separating wider terraces with the periodicity determined by the (23 × √3)− Au(111) reconstruction. At higher coverages, hexagonal layers with a lattice constant of 1.0 nm grow out from the steps on both the upper and lower terraces. The adsorption of the fullerenes lifts the reconstruction indicating a strong interaction between the fullerenes and Au(111). STM indicates that two ordered commensurate structures predominate on the Au(111) surface: (1) a layer with a periodicity of approximately 38 Au spacings; and (2) a layer with a (2√3 × 2√3)R30° unit cell. Second layer molecules were found to display no affinity for step edges. On Au(111), the second layer desorbs at 300°C, while the first layer is strongly bound and does not begin to desorb until 500°C. After annealing to 500°C the remaining C 60 is largely disordered. Intramolecular structure was observed within molecules at the step edges and in the hexagonal arrays.

Nucleation, growth, and structure of fullerene films on Au(111)

Nucleation, growth, and structure of fullerene films on Au(111)