Luminescent mesoporous films containing europium III complex

Abstract

Abstract Mesoporous materials have large specific area and pore volume, low density, and high mechanical and thermal stability. These materials can be applied as catalysts, shape-selective adsorbents, chemical sensors, and capsules for controlled release of therapeutic agents; they can also be employed in microelectronics, electro-optics, and other emerging nanotechnologies. In this study, we used the sol–gel process to obtain mesoporous silica films by dip coating. A trispyrazolyl borate, or scorpionate (Tp), complex containing europium III was incorporated into a mesoporous silica film via wet impregnation. The silica precursor solution was prepared by homogenizing tetraethylorthosilicate, deionized water, ethanol, and cetyltrimethylammonium bromide. The films were obtained by the dip-coating technique (between one and two depositions) at a deposition rate of 300 mm/min; borosilicate glasses were used as substrates. The films were characterized by X-ray diffraction, infrared spectroscopy, transmittance, and europium III photoluminescence analyses. X-ray diffraction showed that mesoporous silica was present in the substrate. Silica without thermal treatment and silica treated at 200 °C presented pore diameters of 3.75 and 3.45 nm, respectively. Thermal treatment eliminated the surfactant. The excitation and emission spectra confirmed that the luminescent europium III complex was incorporated into the mesoporous silica film, which can be employed as sensor.