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In this work, we have investigated how the concentration of Gd ions affects the structural and luminescent properties of niobium oxide-based matrices doped with Eu ions obtained by the adapted non-hydrolytic sol-gel route. X-ray diffractograms revealed that increasing the concentration of Gd ions favored the onset of the GdO structure decreasing the GdNbO phase. The excitation spectra (λ = 613 nm) presented bands corresponding to theF → L transitions (L = D, G, and L, where J = 0-7), attributed to the Eu ions, and a broad band at 270 nm, assigned to the charge transfer of the [Formula: see text] group. The emission spectra contained bands refer to the D → F internal configuration transitions (J = 0, 1, 2, 3, and 4). Finally, the CIE chromaticity coordinates met the standard for the color red established by the National Television Standard Committee (NTSC).

YTTRIUM ALUMINUM OXIDE DOPED WITH Yb 3+ AND Er 3+ INCORPORATED INTO POLYAMIDE MEMBRANE. Lanthanide ions have special light emission, which can occur through descending and ascending energy conversion. Ascending energy conversion is especially interesting for bioapplications because excitation in the infrared region does not excite biomolecules and therefore does not interfere in detection, not to mention that it penetrates deeper in the skin. Here, we synthesized yttrium and aluminum oxide doped with Yb 3+ and Er 3+ ions via the non-hydrolytic sol-gel methodology. The doped matrix was incorporated and dispersed over a polyamide membrane obtained by Additive Manufacturing. X-ray diffraction revealed that a mixture of yttrium aluminum monoclinic and garnet phases emerged. Upon excitation at 980 nm in the Yb 3+ ion, the Er 3+ presented more intense emission as a function of the laser power, which favored red emission. The intensities of the bands corresponding to the 4 S 3/2 → 4 I 15/2 (563 nm) and 5 F 9/2 → 4 I 15/2 (660 nm) transitions involved the absorption of two photons. The oxide incorporated into the polyamide membrane presented the same behavior. After coating with polyetherimide, the latter system was resistant to 5.1 W laser, which paves the way for new applications.

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Thin films of lanthanide orthoniobate LnNbO4 (LnNO) and orthotantalate LnTaO4 (LnTO), (Ln = Nd, Sm, Eu) were fabricated using the sol–gel method with subsequent spin‐coating on the PbZrO3/Al2O3 substrate and annealing at 1000°C. X‐ray diffraction patterns showed monoclinic M‐LnNbO4 or M´‐LnTaO4, which coexists with the orthorhombic or tetragonal phase. X‐ray photoelectron spectroscopy demonstrated the presence of Nd3+, Sm3+/Sm2+ and Eu3+/Eu2+ ions. The luminescence properties of polymorphic films were investigated. Excitation spectra of PbZrO3 interlayer represented broad bands at 410 and 550 nm that were assigned to charge transfer bands (CTB). In all films, the CTB broad band at ~275 nm related to charge transfer transition of Ln3+→O2− and NbO43− or TaO43− groups. In excitation spectra, 4I9/2→4G5/2 (Nd3+), 6H5/2→6P3/2 (Sm3+) and 7F0→5L6 (Eu3+) transitions (at 585, 402 and 395 nm), respectively were found to be more intense than any other Ln3+ transition. The emission spectra showed narrow and intense bands at 1065, 600, and 614 nm that were ascribed to Nd3+, Sm3+, and Eu3+ 4f–f intraconfigurational transitions 4F3/2→4I11/2, 4G5/2→6H7/2, and 5D0→7F2, respectively. The excellent luminescence properties of films make them new potential groups for visible and/or near‐infrared applications such as sensors and imaging equipment.