Electron energy-loss study of titania particles
R.J. Gonzalez, A.L. Ritter
(Virginia Tech)
Small titania particles, prepared by hydrolysis and condensation using in-situ steric stabilization, have been studied by high-energy, transmission, electron energy-loss spectroscopy. Electron diffraction patterns and energy-loss spectra as a function of momentum transfer were measured for as-prepared particles (amorphous titania), particles annealed at 600¡C (primarily anatase), and particles annealed at 1000¡C (primarily rutile). The energy-loss spectra at low momentum disagreed with the loss function calculated from optical data (rutile) and disagreed with theory (rutile and anatase). The data was fit by an Elliot-like model for a resonant exciton interacting with a continuum of levels. The translational effective mass of the exciton derived from the fitting was quite large indicating that it was self-trapped.
Keywords: optical materials; electronic structure
Order No.: JA806-034 © 1998 MRS
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