White-light emitting (Y,Gd)PO4:Dy3+ microspheres: Gd3+ mediated morphology tailoring and selective energy transfer and correlation of photoluminescence behaviors

Abstract

Well-dispersed and one micron-sized spheres of tetragonal Y/Gd/Dy ternary phosphate have been facilely synthesized via microwave-assisted homogeneous precipitation. The spheres are polycrystalline, and the particle size gradually decreases with increasing Gd3+ content. Excessive doping of Gd3+ leads to the appearance of hexagonal-structured rods on particle surface. The Y/Gd/Dy ternary phosphor exhibits two predominant emission peaks, with a blue one at ∼483 nm and a yellow one at ∼575 nm, thus yielding a white light-emitting color. Mainly due to the efficient energy transfer, incorporation of Gd3+ resulted in enhanced luminescence intensity, with nearly a 1000% increase at 575 nm. Because the selective energy transfer from Gd3+ to the 4F9/2→6H13/2 transition of Dy3+ takes the dominant role, more remarkable enhanced intensity at ∼575 nm than that at ∼483 nm was observed. Enhanced emission intensity, shorter lifetimes, and almost the same CIE coordinates were observed at a higher calcination temperature.