Hybrid nanosilicas constitute a broad study field. They find application as catalysts, pigments, drug delivery systems, and biomaterials, among others, and it is possible to obtain them via the sol-gel methodology. Lanthanide ions present special properties like light emission. Their incorporation into a silica matrix can enhance their luminescent properties, which enables their application as luminescent markers. This work reports on (i) the preparation of luminescent spherical hybrid silica nanoparticles by the hydrolytic sol-gel methodology, (ii) doping of the resulting matrix with the europium(III) ion or its complex with 1,10-phenanthroline, and (iii) characterization of the final powders by scanning electron microscopy, infrared spectroscopy, X-ray diffraction, and europium(III) ion photoluminescence. The synthesized materials consisted of hybrid, amorphous, polydispersed nonspherical silicas with average size of 180 nm. Photoluminescence confirmed incorporation of the europium(III) ion and its complex into the silica matrix-the ligand-metal charge transfer band emerged in the excitation spectra. The emission spectra presented the bands corresponding to the transition of the excited state (5)D0 level to (7)FJ (J = 0, 1, 2, 3 and 4). The main emission occurred in the red region; the lifetime was long. These characteristics indicated that the prepared nanospherical hybrid silicas could act as luminescent markers.

In this article, the sol-gel methodology was used for coating an acrylonitrile butadiene styrene (ABS) polymer prepared by the rapid prototyping technology with a colloid containing the europium III dipicolinic complex, which presents high emission when excited in the ultraviolet region. Either acid or base was used for treatment of the ABS polymer, with a view to activating its surface. The thermal analysis evidenced a residual mass after 600°C, which indicated that the coating adhered to the substrate. X-ray diffraction analysis showed that the structure of the ABS polymer was not affected by the sol-gel treatment. The large band centered at 287 nm, ascribed to ligand-metal charge transfer, can be used to excite the europium III dipicolinic complex in the ultraviolet C and ultraviolet B regions. The emission appears in the characteristic red region of the electromagnetic spectrum. These results indicate that the obtained material is a candidate for use as ultraviolet sensor.

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