Gas-phase condensation of nanometer- and subnanometer-sized carbon grains and polycyclic aromatic hydrocarbons

Nanometer- and subnanometer-sized carbonaceous particles have been synthesized via gas-phase condensation processes in laser ablation and laser pyrolysis experiments. Depending on the laser power which affects the temperature in the reaction zone, different carbonaceous nanomaterials are obtained. Low temperatures favor the production of polycyclic aromatic hydrocarbons whereas, at comparably higher temperatures, fullerene- or onion-like nanoparticles are formed. To characterize the carbonaceous species, we employed high-resolution transmission electron microscopy, UV/vis and IR absorption spectroscopy, gas and liquid chromatography, as well as matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy.