High-pressure Raman spectroscopy of carbon onions and nanocapsules

摘要

We report high-pressure Raman spectra of carbon onions and nanocapsules investigated by diamond anvil cell experiments. The pressure coefficient and elastic behavior of carbon onions and nanocapsules are found to be very similar to those of multiwall carbon nanotubes. Additionally, detectable structure changes, particularly the collapse of the concentric graphite structure, cannot been seen at pressures as high as ～20 GPa, demonstrating that carbon onions and nanocapsules have significant hardness and can sustain very high pressures.