Color-tunable emission and energy transfer investigation in SrY(PO):Ce,Tb phosphors for white LEDs.

A novel color-tunable phosphor SrY(PO):Ce,Tb 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 Ce to Tb via a dipole-dipole mechanism, where Ce 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 Ce and Tb 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.