Titanium dioxide synthesized using titanium chloride: size effect study using Raman spectroscopy and photoluminescence

Abstract

Titanium dioxide nanocrystals were prepared by the wet chemical method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering (RS) and photoluminescence techniques. The XRD pattern shows the formation of single phase anatase structure of average sizes ∼7 nm (sample A) and ∼15 nm (sample B) for two samples. Additionally, TEM and RS were used to confirm the anatase crystal structure for both samples. The PL spectra show that the intensity of the sample A is more than that of sample B, which has been attributed to defect(s) and particle size variation. A modified phonon confinement model incorporating particle size distribution function and averaged dispersion curves for two most dispersive phonon branch ( -X direction) have been used to interpret the size effect in Raman spectra. The obtained Raman peak shift and full width at half-maximum agree well with the experimental data. Our observations suggest that the phonon confinement effects are responsible for a significant shift and broadening for the Raman peaks.

Phase control of yttrium (Y)-doped TiO 2 nanofibers and intensive visible photoluminescence

“…It is clear from Table 2 that with increasing Y-doping concentration, the FWHM and frequency of the peaks increased and blue-shifted, respectively, which indicates the decrease of grain sizes of TiO 2 nanofibers upon increasing Y-doping content. Hence, the increase in FWHM and blue-shift of Raman peaks observed in TiO 2 nanofibers can be ascribed to phonon confinement effect and surface strain effect, usually observed in nanostructured materials [34]. These outcomes are in good agreement with Scherrer's formula from XRD studies.…”

Sub-10 nm rutile titanium dioxide nanoparticles for efficient visible-light-driven photocatalytic hydrogen production

“…For T-1, an obvious blue shift and broadening of the E g band (B25 cm À 1 , Fig. 1b) is clearly observed due to the photon-confinement effects induced by defects 23,39 .…”

Effect of electron beam irradiation on the structure and optical properties of nickel oxide nanocubes

“…26 The PL spectra of irradiated samples have larger intensities relative to pure sample, due to defects and particle size variation caused by EB irradiation. 27 Also, the PL intensity increases with dose rate, and the sample S4 irradiated with 6 kGy dose exhibits much larger intensity compared with other samples due to increased absorption over the UV and visible range. Intermediate energy levels are formed with favourable characteristics due to EB irradiation, which are necessary for recombination process (electron/hole) for the improvement of the PL emission at room temperature.…”