The aim of this work is to report on the luminescence properties of BaZnSiO4 activated by Eu3+ and Mn2+ ions. Doped and undoped powder samples were prepared by solid-state reaction starting from oxides and carbonates or Ba2SiO4:Eu3+ and Zn2SiO4:Mn2+ precursors. X-ray diffraction powder data, IR vibrational, and UV−vis luminescence spectroscopies were carried out. Results showed that doped and undoped samples from both types of precursors have the same structure and crystallize with a superstructure of hexagonal kalsilite. Vibrational spectroscopy has confirmed the formation of a silicate group, which outlines differences between products and silicate precursors. The observed luminescence assigned to Eu3+ and Mn2+ transitions covered most parts of the visible spectrum, an important requirement for phosphors in fluorescent low-pressure mercury vapor lamps.

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This work reports on the structural characterization and on the low-temperature upconversion spectroscopy of the Y2O3:2%Er,1%Yb nanophosphor prepared by thermal decomposition of a polymeric resin (Pechini’s method [U.S. Patent No. 3,330,697 (July 11 1967)]). The average particle size evaluated from transmission electron microscopy lies in the range of 05–25nm. The high-resolution upconversion luminescence spectrum at 10K in the ultraviolet to near infrared (UV-NIR) spectral regions shows narrow lines, characteristic of Er3+ transitions occupying both Y3+ sites with point symmetries C2 and C3i in the oxide cubic system. The excitation spectrum at 10K in the IR region was used to monitor the green upconversion and IR luminescences and it displayed Er and Yb lines. Power dependence measurements at 298 and 10K indicate that the main upconversion mechanism is a two-photon excitation process. The temperature dependence of the upconversion luminescence shows a decrease in the emission intensity with increasing temperature, and such decrease is much more evident for the emission in the violet than in the green and the red regions.

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The upconverter phosphors studied herein have different percentages of Er3+ and Yb3+ as doping ions in different Y3+ matrixes (Y2O3, Y2O2S), and were prepared from different precursors (polymeric resin, oxalate, basic carbonate) and method (combustion). Upconversion emission spectra were recorded at 298 K for all the doped samples in the visible region, for efficiency and Green/Red emission relative intensity comparisons. Therefore, an investigation of the influence of the doping ion concentration, particle size and host lattice on the upconversion process is provided in view of the UPT (Upconverting phosphor technology application). On the basis of the results, it was possible to evaluate the best combination for a specific assay, considering whether it is advantageous to have the greatest contribution from the green or red emissions, or from both in comparable intensities.

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The present paper reports on the effect of Eu 3+ concentration (1-5%, considering a charge compensation mechanism) on the structural, morphological and spectroscopic properties of Ba 2 SiO 4 produced by using a novel approach that involves an adapted sol-gel route. XRD data showed that high crystalline and single phase doped Ba 2 SiO 4 samples were prepared at lower calcination temperature (1100 C) compared to the standard solid-state method ($1300 C occupying ordinary host lattice sites. Finally, the 4%-doped sample exhibited the highest relative emission intensity while the 5%-doped, the highest quantum efficiency (72.6%) which qualifies these materials as potential candidates to be used as red phosphors for solid state lightning.