Luminescence and energy-transfer properties of color-tunable Ca2Mg0.25Al1.5Si1.25O7:Ce3+/Eu2+/Tb3+ phosphors for ultraviolet light-emitting diodes

A series of Ca2Mg0.25Al1.5Si1.25O7:Ce3+/Eu2+/Tb3+ phosphors was been prepared via a conventional high temperature solid-state reaction and their luminescence properties were studied. The emission spectra of Ca2Mg0.25Al1.5Si1.25O7:Ce3+,Eu2+ and Ca2Mg0.25Al1.5Si1.25O7:Ce3+,Tb3+ phosphors show not only a band due to Ce3+ ions (409nm) but also as a band due to Eu2+ (520nm) and Tb3+ (542nm) ions. More importantly, the effective energy transfer from Ce3+ to Eu2+ and Tb3+ ions was confirmed and investigated by emission/excitation spectra and luminescent decay behaviors. Furthermore, the energy level scheme and energy transfer mechanism were investigated and were demonstrated to be of resonant type via dipole-dipole (Ce3+ to Eu2+) and dipole-quadrupole (Ce3+ to Tb3+) reactions, respectively. Under excitation at 350nm, the emitting color could be changed from blue to green by adjusting the relative doping concentration of Ce3+ and Eu2+ ions as well as Ce3+ and Tb3+ ions. The above results indicate that Ca2Mg0.25Al1.5Si1.25O7:Ce3+,Eu2+/Tb3+ are promising single-phase blue-to-green phosphors for application in phosphor conversion white-light-emitting diodes. Copyright (c) 2015 John Wiley & Sons, Ltd.