Oxonitridosilicate Y10(Si6O22N2)O2:Ce3+,Mn2+ Phosphors: A Facile Synthesis via the Soft-Chemical Ammonolysis Process, Luminescence, and Energy-Transfer Properties

Ce3+- and/or Mn2+-activated Y-10(Si6O22N2)O-2 phosphors have been prepared via a soft-chemical ammonolysis method. Structure refinement, scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared, and thermogravimetry analysis have been employed to characterize the phase purity, crystal structure, morphology, crystallization condition, chemical composition, and thermal stability of the products. The photoluminescence and cathodoluminescence properties for Ce3+- and Mn2+-doped Y-10(Si6O22N2)O-2 phosphors were studied in detail. For Ce3+/Mn2+ singly doped Y-10(Si6O22N2)O-2 phosphors, typical emissions of Ce3+ (blue) and Mn2+ (reddish-orange) ions can be observed. Especially, Ce3+ emission at different lattice sites 4f and 6h has been identified and discussed. Energy transfer from Ce3+(I) and Ce3+(II) to Mn2+ ions in Y-10(Si6O22N2)O-2:Ce3+,Mn2+ samples has been validated and confirmed by the photoluminescence spectra and luminescence decay times. A color-tunable emission in Y-10(Si6O22N2)O-2:Ce3+,Mn2+ phosphors can be achieved by an energy-transfer process and a change in the doping concentration of the activators. The temperature-dependent photoluminescence properties and degradation property of cathodoluminescence under continuous electron bombardment of as-synthesized phosphors prove that the Y-10(Si6O22N2)O-2 host has good stability. Therefore, the Y-10(Si6O22N2)O-2:Ce3+,Mn2+ phosphors may potentially serve as single-phase blue/reddish-orange phosphors for white-light-emitting diodes and field-emission displays.