Preparation and properties of ZnO nanoparticles in the mesoporous silica matrix

In the present work a novel variant of synthesis of ZnO nanoparticles in the mesoporous silica matrix was suggested. The method is based on the introduction of a hydrophobic Zn compound, Zn acetylacetonate, into the hydrophobic part of silica-surfactant composite, followed by thermal modification. The ZnO content in the as-synthesized composites attains 14.6 wt.%, which exceeds most previously reported values for ZnO/mesoporous silica nanocomposites. The samples were characterized by SAXS, chemical analysis, TEM, XRD, EDX, UV-Vis and photoluminescent (PL) spectroscopy. The UV-Vis spectra of the composites show a significant blue shift of an absorption band demonstrating an increase of ZnO band gap energy due to the quantum confinement effect. The PL spectra under the excitation with 337 nm light show a narrow UV emission band of ZnO at 370 nm, while emission in the visible range of spectra almost disappeared. The intensity ratio IUV/IVis for the as-synthesized nanocomposites is up to 65 (at 77 K).