The development of Ce-activated (Gd,Lu)3Al5O12 garnet solid solutions as efficient yellow-emitting phosphors

Ce-activated Gd3Al5O12 garnet, effectively stabilized by Lu3+ doping, has been developed for new yellow-emitting phosphors. The powder processing of [(Gd1−xLux )1−yCey]3Al5O12 solid solutions was achieved through precursor synthesis via carbonate precipitation, followed by annealing. The resultant (Gd,Lu)AG : Ce phosphor particles exhibit typical yellow emission at ∼ 570 nm (5d–4f transition of Ce) upon blue-light excitation at ∼ 457 nm (the F5/2–5d transition of Ce). The quenching concentration of Ce was determined to be ∼ 1.0 at% (y = 0.01) and the quenching mechanism was suggested to be driven by exchange interactions. The best luminescent [(Gd0.9Lu0.1)0.99Ce0.01]AG phosphor is comparative to the well-known YAG : Ce in emission intensity but has a substantially red-shifted emission band that is desired for warm-white lighting. The effects of processing temperature (1000–1500 C) on the spectroscopic properties of the phosphors, especially those of Lu3+/Ce, were thoroughly investigated and discussed from the centroid position and crystal field splitting of the Ce 5d energy levels.