Preparation and luminescence properties of Ce3+ and Ce3+/Tb3+-activated Y4Si2O7N2 phosphors

Abstract

Ce³⁺ and Ce³⁺/Tb³⁺-activated Y₄Si₂O₇N₂ phosphors are synthesized by the solid-state method, which can be efficiently excited by near ultraviolet (UV) light emitting diode (LED) chips. The PL spectrum of Y₄Si₂O₇N₂:Ce³⁺ shows a broad hump between 380 and 650 nm, assigned to the electron transition from the 4f energy level to different 5d sub levels of the Ce³⁺ ions at different Y³⁺ sites. The color of the Y₄Si₂O₇N₂:Ce³⁺ phosphor can shift from blue to green by introducing Tb³⁺. In addition, the energy transfer process from Ce³⁺ to Tb³⁺ in the Y₄Si₂O₇N₂ host was investigated and discussed in terms of both the luminescence spectra and decay curves. The energy transfer critical distance has been calculated and evaluated by the concentration quenching method. Therefore, the Ce³⁺ and Ce³⁺/Tb³⁺-activated Y₄Si₂O₇N₂ phosphors can serve as key materials for phosphor-converted white-light UV-LEDs.