The Ag nanoparticles-SiO2–ZnO film sandwiched structure was fabricated by depositing ZnO films on silica substrates which had been implanted by Ag ions. Enhancement of emission of the sandwiched structure was observed. The enhancement emission is caused by the resonant coupling between the surface plasmons of Ag and the spontaneous emission of ZnO. The enhancement mechanism is confirmed by optical absorption spectra, transmission electron microscopy, and time-resolved photoluminescence. The key is to deposit ZnO on Ag nanoparticles covered with silica to prevent oxidation of Ag by direct contact with ZnO. This structure will be very useful for highly efficient optoelectronic devices.
Connected zinc oxide (ZnO) nanoparticles are successfully synthesized by a simple solution-based chemical route that uses evaporation and concentration technology. The influences of processing parameters, especially the evaporation and concentration time on the size and morphology of the nanoparticles, have been investigated by transmission electron microscopy (TEM) and high-resolution TEM (HRTEM). The structure and optical properties are systematically characterized by X-ray diffraction (XRD), UV/Vis spectrophotometery, and fluorescence spectroscopy (FL). It is found that the average diameter and morphology are strongly affected by the evaporation and concentration time. Additionally, the formation mechanism of the nanoparticles is also discussed. The studies revealed that the evaporation and concentration are important aggregation or nucleation processes for ZnO growth, which leads to the macro-differences in morphology. These results provide some insight into the growth mechanism of ZnO nanostructures. The synthetic strategy developed in this study may also be extended to the preparation of other nanomaterials and promising applications in various fields of nanotechnology.
The development of synthetic process for hollow silica materials is an issue of considerable topical interest. While a number of chemical routes are available and are extensively used, the diameter of hollow silica often large than 50 nm. Here, we report on a facial route to synthesis ultrafine hollow silica nanoparticles (the diameter of ca. 24 nm) with high surface area by using cetyltrimethylammmonium bromide (CTAB) and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) as co-templates and subsequent annealing treatment. When the hollow magnetite nanoparticles were introduced into the reaction, the ultrafine magnetic hollow silica nanoparticles with the diameter of ca. 32 nm were obtained correspondingly. Transmission electron microscopy studies confirm that the nanoparticles are composed of amorphous silica and that the majority of them are hollow.
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