Individual TiO_2 nanocrystals probed by resonant Rayleigh scattering spectroscopy

摘要

Individual titanium dioxide (TiO_2) nanocrystals with bandgaps in the deep ultraviolet (DUV) wavelength range were investigated using resonant Rayleigh scattering spectroscopy. A microscopy system that was switchable from dark-field imaging to scattering spectroscopy was specifically constructed for a broadband UV light source. Weak Rayleigh scattering from a single nanocrystal a few nanometers in size was obtained through the UV excitation resonance and high positional reproducibility of the switching optics. Individual nanocrystals exhibited specific intrinsic bandgaps depending on their size, shape, and crystallinity, greatly affecting their photocatalytic efficiency.