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

Abstract

A series of emission-tunable Na_1−xAl_1+2xSi_1−2xO₄: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.