Effect of gadolinium incorporation on the structure and luminescence properties of niobium-based materials

In this work, we have investigated how the concentration of Gd3+ ions affects the structural and luminescent properties of niobium oxide-based matrices doped with Eu3+ ions obtained by the adapted non-hydrolytic sol-gel route. X-ray diffractograms revealed that increasing the concentration of Gd3+ ions favored the onset of the Gd2O3 structure decreasing the GdNbO4 phase. The excitation spectra (lambda(em) = 613 nm) presented bands corresponding to the F-7(0) -> L-5(J) transitions (L = D, G, and L, where J = 0-7), attributed to the Eu3+ ions, and a broad band at 270 nm, assigned to the charge transfer of the NbO43- group. The emission spectra contained bands refer to the D-5(0) -> F-7(J) 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).