ALL CARBON NON-COVALENT EXOHEDRAL HYBRIDS: C60 AGGREGATES ON NANOTUBE NETWORKS

Non-covalent hybrids comprising fullerenes and carbon nanotubes (CNTs) exhibit tuneable structures and unique properties. In spite of theoretical predictions, experimental realization of exohedral non-covalent hybridization of unmodified C₆₀ fullerenes and CNTs was not reported befort. Here we report preparation and structural characterization of exohedral hybrids comprising pristine fullerenes - CNTs networks. Unluke covalent fullerene-SWNT hybrids such as carbon nanobud (CNB) exohedral hybrids may form via van der Waals (vdW) dispersion interactions where the sp² hybridization is preserved. Here we present the preparation of C₆₀-CNT exhoderal hybrids via thermal deposition of fullerenes onto pre-assembled, random 3D-networks of individual, pristine CNTs. Structural characterized via HRTEM and Electron Diffraction reveal that the fullerenes form fullerite nanocrystals. Annealing at low temperature (80 °C) results in re-organization of the C₆₀ nanocrsytals into nanometric layers, forming a CNT- C₆₀ core-shell like cylindrical hybrids. Raman spectroscopy and the observed high mobility of the fullerenes at the CNT surface support the assumption that the exohedral hybrids are of vdW type. The approach presented here allows preparation of CNT- C₆₀ exohedral hybrids with controlled morphology and tunable properties. The CNT –fullerene hybrids may serve to shape the nano-morphology of the active layer in polymer-fullerene bulk-heterojunction solar cells.