Optical properties of ZnO loaded in mesoporous silica
- 27 June 2000
- journal article
- Published by IOP Publishing in Journal of Physics: Condensed Matter
- Vol. 12 (28), 6265-6270
- https://doi.org/10.1088/0953-8984/12/28/322
Abstract
The optical absorption and photoluminescence (PL) of ZnO loaded in mesoporous silica have been investigated. These ZnO/SiO2 composites are synthesized by impregnation of mesoporous silica with an aqueous solution of zinc acetate, followed by firing at 550 °C. A significant blue shift of the absorption edge compared to that of bulk ZnO in the absorption spectra is observed, and the band gap luminescence of ZnO is predominant in the emission spectrum, while the defect induced green luminescence, typical of ZnO, does not appear. However, the above sample, after additional annealing at 350 °C in air for three hours, exhibits an absorption edge (365 nm) near to that of the bulk ZnO; the colour of the sample also turns to yellowish from colourless, and green luminescence also appears. Combining the analysis of x-ray photoelectron spectroscopy (XPS), we propose that Zn-O-Si cross linking bonds formed in the interface between ZnO and the pore walls of silica have a great influence on the optical properties of ZnO/SiO2 before the additional annealing at 350 °C and the corresponding optical properties reflect both those of SiO2 and ZnO. After annealing, the Zn-O-Si cross linking bonds mentioned above are destroyed, and the optical properties of ZnO are exhibited alone.Keywords
This publication has 17 references indexed in Scilit:
- ZnO quantum particle thin films fabricated by electrophoretic depositionApplied Physics Letters, 1999
- Spectroscopic and structural characterization of electrochemically grown ZnO quantum dotsJournal of Applied Physics, 1999
- On the optical band gap of zinc oxideJournal of Applied Physics, 1998
- Enhancement effect of photoluminescence in assemblies of nano-ZnO particles/silica aerogelsJournal of Applied Physics, 1998
- Complex Nature of the UV and Visible Fluorescence of Colloidal ZnO NanoparticlesThe Journal of Physical Chemistry B, 1998
- Synthesis and structural and optical properties of mesoporous silica containing silver nanoparticlesJournal of Physics: Condensed Matter, 1997
- Mechanisms behind green photoluminescence in ZnO phosphor powdersJournal of Applied Physics, 1996
- Diffusion and optical properties of Nd-doped sol-gel silica glassesJournal of Non-Crystalline Solids, 1995
- Photochemistry of semiconductor colloids. Preparation of extremely small ZnO particles, fluorescence phenomena and size quantization effectsChemical Physics Letters, 1985
- Photoluminescence and photocatalytic activity of highly dispersed titanium oxide anchored onto porous Vycor glassThe Journal of Physical Chemistry, 1985