Synthesis, structure and luminescence characteristics of La3Ga5SiO14:Pr3+ phosphors

Abstract

In this study, we synthesized series of La3Ga5SiO14:Pr3+ phosphors by high-temperature solid-state reactions. For the synthesized phosphors, X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive spectrum (EDS), Raman, infrared (IR), absorption, photoluminescence (PL) and photoluminescence excitation (PLE) characterizations and decay characteristics were performed. The XRD patterns indicate that the synthesized phosphors have the same D32 (P321) structure with La3Ga5SiO14 host. The SEM image and EDS pattern show the irregular morphology and the combined La, Ga, Si, O and Pr elements for the synthesized phosphors. The room temperature Raman and IR spectra show that the phonon modes of the La3Ga5SiO14:Pr3+ phosphors follow the overall mode distributions of La3Ga5SiO14 and no appreciable changes in the phonon properties are observed, indicating that the force fields in the La3Ga5SiO14:Pr3+ lattice are not strongly altered by Pr3+ doping. The UV-Vis absorption spectra show that the phosphors contain a strong absorption band and several moderate bands resulting from the 4f-5d and f-f transitions of Pr3+ ions, respectively. La3Ga5SiO14:Pr3+ phosphors produce white light when λex = 255 nm. On the basis of emission data, the concentration quenching mechanism of the Pr3+ emission was speculated as the dipole-dipole interaction. The decay time and thermal stability were investigated, and the CIE coordinates with the corresponding correlated color temperatures were also calculated.