Novel emission-tunable oxyapatites-type phosphors: Synthesis, luminescent properties and the applications in white light emitting diodes with higher color rendering index. (April 2017) - Guo, Qingfeng
Abstract: Developing color-tunable phosphors via the introduction of co-doping activators and sensitizers to the host with energy transfer processes has been a state-of-the-art topic for a long time. In this work, novel emission-tunable oxyapatites-type Ba10 (PO4 )6 O:Eu 2+, Tb 3+ /Li + phosphors were prepared via a high temperature solid state reaction for the applications in white light emitting diodes ( w -LEDs) with higher color rendering index. Tunable colors from blue to green can be realized in the Ba10 (PO4 )6 O:Eu 2+, Tb 3+ /Li + by varying the relative ratios of Eu 2+ to Tb 3+, showing good absorption in the range of 230–400 nm. The energy transfer mechanism from Eu 2+ to Tb 3+ ions was demonstrated to be a quadrupole-quadrupole interaction by combining the Inokuti-Hirayama (IH) model and Reisfeld's approximation. Importantly, a prototype white lamp was packaged by mixing Ba9.83 (PO4 )6 O: 0.03Eu 2+, 0.07Tb 3+, 0.07Li + and commercial red phosphor CaAlSiN3 : Eu 2+, and the lamp exhibits a higher color rendering index (Ra = 92 and R9 = 56) and warm correlated color temperature of 4361 K for the actual application. Better luminescent properties compared to commercial Y3 Al5 O12 :Ce 3+ -based w -LEDs, indicating that Ba10 (PO4 )6 O: Eu 2+, Tb 3+ /Li + phosphors are emerging as potential phosphor-converted w -LEDs. Highlights: Broad-band excited Ba10 (PO4 )6 O:Eu 2+, Tb 3+ /Li + phosphors were prepared. Efficient energy transfer from Eu 2+ to Tb 3+ in Ba10 (PO4 )6 O were investigated. Ba10 (PO4 )6 O:Eu 2+, Tb 3+ /Li + have potential applications as blue-green emitting phosphors in w-LEDs.