One-pot photoetching to control size, surface oxygen groups, and dispersion of fullerene particles in water

Photoetching was used to achieve continuous size-control (i.e., from ca. 120 nm to ca. 40 nm), the generation of oxygen groups including hydroxyl, and the improved dispersion of C60 particles in water in a one-pot reaction. Dynamic light scattering (DLS), scanning electron microscopy, and UV–visible spectroscopic measurements indicated that the C60 particle size and absorbance decreased as the light irradiation time increased, while its dispersion also improved. UV–visible spectroscopy and DLS furthermore showed that without irradiation or under an inert atmosphere, the particle size and absorbance remained constant, indicating that the size decrease could be attributed to photochemical reactions involving C60 and O2. Fourier transform infrared spectra and element analysis revealed the introduction of oxygen groups including hydroxyl on the C60 cages and their subsequent destruction by light irradiation. The mechanism for the observed phenomena is discussed.