Synthesis and spectroscopic investigations of trivalent europium-doped Z2Si3O8 (Z = Mg, Ca and Sr) nanophosphors for display applications

Abstract

To explore the silicate lattice-based nanophosphors, a series of Eu3+-doped Z2Si3O8 (Z = Mg, Ca and Sr) materials were prepared by sol–gel procedure. The metal nitrates and silica powder were used as precursor components for the synthesis of these luminescent materials. Photoluminescence (PL) emission spectra, powder X-ray diffraction (PXRD), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) spectroscopic techniques were applied for the characterization of the fabricated materials. Three peaks were observed at 589, 613 and 650–652 nm corresponding to 5D0 → 7F1-3 transition in PL emission spectra. Upon 395 nm excitation and at 0.03 mol Eu3+, these nanophosphors displayed optimum photoluminescence with the most intense peak analogous to 5D0 → 7F2 transition of dopant ion. The as-prepared phosphor materials were re-heated at 1050 and 1150 °C to observe the consequences of higher temperatures on the emission intensity and crystal lattice. XRD analysis confirmed that all the synthesized materials were of crystalline nature, and the crystallinity was observed to be improved by increasing the temperature. In the FTIR spectrum, peaks at 483 and 610 cm−1 proved the existence of SiO4 group in Ca2Si3O8, and the peak centered at 417 cm−1 confirmed the presence of MgO6 octahedral in Mg2Si3O8 materials. TEM images were used to determine the particle size (13–35 nm) and to study the three-dimensional structure of nanophosphor materials. The experimental studies indicate that these materials may be promising as red-emitting nanophosphors for white light-emitting diodes.