Raman scattering study on anatase TiO₂nanocrystals

TLDR

The study uses Raman scattering to examine how the anatase phase evolves during annealing and to assess how interfacial vibrations affect the Raman linewidth. TiO₂ nanocrystals were synthesized by hydrolyzing tetrabutyl titanate, annealed at 100–650 °C to yield 6.8–27.9 nm particles, whose crystal structures and sizes were characterized by XRD, and Raman spectroscopy was employed to study phase evolution and interfacial vibration effects. Phonon confinement and non‑stoichiometry cause the lowest‑frequency Eg Raman mode to blueshift and broaden.

Abstract

Titanium dioxide (TiO 2 ) nanocrystals are prepared by a hydrolysis process of tetrabutyl titanate. Nanocrystal samples with various sizes of 6.8-27.9 nm are obtained after annealing from 100 to 650 °C. The crystal structures and the average particle sizes are examined using x-ray diffraction. Raman scattering was employed to investigate the evolution of the anatase phase in the nanocrystals during annealing. Phonon confinement and non-stoichiometry effects are responsible for the blueshift and broadening of the lowest-frequency E g Raman mode. The influence of interfacial vibrations on the Raman linewidth is also discussed.