Bridging C60 by silicon : towards non-van der Waals C60-based materials
Résumé
We report the three-dimensional packing of C60 clusters stabilized by the addition of Si. X-ray absorption spectroscopy reveals that Si atoms are in an unusual environment: between two C60, with ten or more carbon neighbors. According to ab initio calculations, the cohesive energy is about 2 eV per Si atom, much higher than the Van der Waals binding energy between two C60. Experiment and calculations both indicate a charge transfer from Si to C60. Eventually, the film may have a local decahedral symmetry.