Ce3+ and Tb3+ doped Ca3Gd(AlO)3(BO3)4 phosphors: Synthesis, tunable photoluminescence, thermal stability, and potential application in white LEDs

Abstract

Novel blue-green-emitting Ca3Gd(AlO)3(BO3)4:Ce3+,Tb3+ phosphors were successfully synthesized via traditional high temperature solid reaction method. X-ray diffraction, luminescence spectroscopy, fluorescence decay time and fluorescent thermal stability tests have been used to characterize the as-prepared samples. The energy transfer from Ce3+ to Tb3+ ions in the Ca3Gd(AlO)3(BO3)4 host has been demonstrated to be by dipole-dipole interaction, and the energy transfer efficiency reached as high as 83.6% for Ca3Gd0.39(AlO)3(BO3)4:0.01Ce3+,0.6Tb3+. The critical distance was calculated to be 9.44 Å according to the concentration quenching method. The emission colour of the obtained phosphors can be tuned appropriately from deep blue (0.169, 0.067) to green (0.347, 0.494) through increasing the doping concentrations of Tb3+. Moreover, the Ca3Gd0.39(AlO)3(BO3)4:0.01Ce3+,0.6Tb3+ phosphor possessed excellent thermal stability at high temperature, and the emission intensity at 423 K was about 87% of that at 303 K. Finally, the fabricated prototype LED device with a BaMgAl10O7:Eu2+ blue phosphor, CaAlSiN3:Eu2+ red phosphor, Ca3Gd0.39(AlO)3(BO3)4:0.01Ce3+,0.6Tb3+ green phosphor and 365 nm-emitting InGaN chip exhibited bright warm white light. The current study shows that Ca3Gd0.39(AlO)3(BO3)4:0.01Ce3+,0.6Tb3+ can be used as a potential green phosphor for white LEDs.