Towards non-van der Waals C60-based materials

We investigated the atomic bonding of Si and C60 theoretically (by ab initio calculations within the local density approximation to the density functional theory) and compared the predictions to experimental X-ray absorption results from Si-C60 films synthesized by the cluster beam deposition technique. Calculations predicted that Si preferentially binds to hexagon–hexagon edges. The geometry of the Si bound to the pentagonal face is metastable. The bond energy is in each case higher than the typical van der Waals bond. Extended X-ray absorption fine structure (EXAFS) measurements revealed Si is bound to the pentagonal face of two C60 molecules in (C60)mSin clusters deposits. Both theoretical and experimental investigations showed that the polymerisation of C60-Si clusters is possible, leading to nanostructured C60-based materials with high binding energy.