A novel strong green phosphor：K₃Gd(PO₄)₂：Ce³⁺, Tb³⁺ for a UV-excited white light-emitting-diode

A series of K₃Gd_1-x-y(PO₄)₂:xCe³⁺, yTb³⁺ phosphors are synthesized by the solid-sate reaction method. X-ray diffraction and photoluminescence spectra are utilized to characterize the structures and luminescence properties of the as-synthesized phosphors. Co-doping of Ce³⁺ enhances the emission intensity of Tb³⁺ greatly through an efficient energy transfer process from Ce³⁺ to Tb³⁺. The energy transfer is confirmed by photoluminescence spectra and decay time curves analysis. The efficiency and mechanism of energy transfer are investigated carefully. Moreover, due to the non-concentration quenching property of K₃Tb(PO₄)₂, the photoluminescence spectra of K₃Tb_1-x(PO4)₂:xCe³⁺ are studied and the results show that when x=0.11 the strongest Tb³⁺ green emission can be realized.