The photoluminescence, thermal properties and tunable color of Na1−xAl1+2xSi1−2xO4:xCe3+/Tb3+/Dy3+via energy transfer: a single-component multicolor-emitting phosphor

A series of emission-tunable Na1−xAl1+2xSi1−2xO4:xCe3+/Tb3+/Dy3+ phosphors were synthesized via a high temperature solid-state reaction method. Luminescence properties, energy transfer from Ce3+ to Tb3+ or Dy3+ ions, color tuning and thermal stability were systematically investigated. Particularly, the charge compensating defect generated by doping of rare earth ions was remedied through Al3+ substituted Si4+. Meanwhile, the emission intensity was significantly improved. The presence and content of various elements were demonstrated through data combined with the crystallographic data from Rietveld refinements and the analysis of SEM and mapping for each element. The results indicated that this charge balance strategy was an effective method. The energy transfer from Ce3+ to Tb3+ and Dy3+ in the co-doped NaAlSiO4 (NAS) samples was deduced from the spectral overlap between the Ce3+ emission and Tb3+/Dy3+ excitation spectra, the photoluminescence spectra and the fluorescence decay curves. The energy transfer mechanisms of Ce3+ to Tb3+ and Dy3+ in the host were studied. And the emission hue can be tuned from blue to green and yellow by properly varying the ratio of Ce3+ and Tb3+/Dy3+. Additionally, the temperature-dependent photoluminescence of the as-prepared phosphors was investigated in detail. All these properties indicate that the developed phosphor may potentially be used as a single-component multicolor-emitting phosphor for UV light-emitting diodes.