Color-tunable emission and energy transfer investigation in Sr3Y(PO4)3:Ce3+,Tb3+ phosphors for white LEDs.

A novel color-tunable phosphor Sr3Y(PO4)3:Ce3+,Tb3+ was synthesized through solid-state reaction method. Several techniques, such as X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectroscopy, were used to investigate the obtained phosphors. Results of luminescence spectra and decay time measurements revealed that an efficient energy transfer occurred from Ce3+ to Tb3+ via a dipole-dipole mechanism, where Ce3+ exhibited a strong excitation band in the near-ultraviolet region. CIE chromaticity coordinates were tuned from deep blue (0.162, 0.090) to green (0.230, 0.411) by adjusting the relative concentrations between Ce3+ and Tb3+ ions. Results revealed that the as-synthesized phosphors had color-tunable characteristics and can be used as promising materials in the field of phosphor-converted white light-emitting diodes.