Lu2O3:Eu3+ transparent, high density, and optical quality thin films were prepared using the sol-gel dip-coating technique, starting with lutetium and europium nitrates as precursors and followed by hydrolysis in an ethanol-ethylene glycol solution. Acetic acid and acetylacetonate were incorporated in order to adjust pH and as a sol stabilizer. In order to increment the thickness of the films and orient the structure, F127 Pluronic acid was incorporated during the sol formation. Structural, morphological, and optical properties of the films were investigated for different F127/Lu molar ratios (0–5) in order to obtain high optical quality films with enhanced thickness compared with the traditional method. X-ray diffraction (XRD) shows that the films present a highly oriented cubic structure <111> beyond 1073 K for a 3-layer film, on silica glass substrates. The thickness, density, porosity, and refractive index evolution of the films were investigated by means of m-lines microscopy along with the morphology by scanning electron microscope (SEM) and luminescent properties.

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In the present work, the effect of SiO 2 was analyzed in different molar ratios (Lu : Si = 4 : 1, 6 : 1, 8 : 1, 10 : 1 and 1 : 0), in order to prepare SiO 2 embedded Lu 2 O 3 :Eu 3+ sol-gel luminescent powders, from a modified PVP-containing solution. The crystalized SiO 2 embedded Lu 2 O 3 :Eu 3+ powders were characterized by Fourier transform infrared spectroscopy revealing the presence of high intensity bands associated with siloxanes groups at 700°C, which could indicate a cross-linked Si-O groups to Lu 2 O 3 :Eu 3+ . X-ray diffraction results showed that cubic phase was present in the powder heat treated at 500°C and remained up to 700°C. The powders SiO 2 embedded Lu 2 O 3 :Eu 3+ powders in molar ratio Lu:Si 4 : 1 and 10 : 1 masked the crystallinity of glass ceramic. The SiO 2 effect on the morphology of the glass ceramic systems was monitored by scanning electron microscopy observations, from these results homogenous particles were obtained for Lu:Si 6 : 1 and 8 : 1 systems. Photoluminescence studies showed that adding silica to the ceramic systems increases the typical emission to around em = 611 nm.

In this work, hybrid TiO 2 nanoparticles embedded in SiO 2 were obtained by means of sol-gel process, testing different proportions of the silicon and titanium oxides to obtain TiO 2 particles with a high surface content of hydroxyl groups. Anatase crystalline form of TiO 2 is a widely used material in active-substance release studies, due to its optimal properties for the transport, distribute and release of different molecules into biological systems. According to the X-ray diffraction analysis, all the proportions of evaluated hybrid systems presented the anatase phase, however, the molar proportion (20:80, TiO 2 :SiO 2) contains a high quantity of hydroxyl groups according to infrared spectroscopy. The spherical morphology of the particles were observed by scanning electron microscopy forming agglomerates. The functionalization of these surfaces was carried out using para-aminobenzoic acid as a drug-binding model that generated a covalent bond between the TiO 2 @SiO 2 system, likewise, thermogravimetric analysis identified the content of functionalized PABA. Dynamic light scattering showed particles and agglomerates around 25609 nm and negative value of zeta (¦)-potential in the molar ratio TiO 2 :SiO 2 20:80-PABA. Finally, we demonstrated that PABA hydrolyzes in the presence of human plasma, recovering the nanoparticularized systems with the hydroxyl groups. The hydroxyl groups on the particle surface promote the incorporation of organic molecules that contain carboxyl groups in their structure.