Color rendering improvement of the YAG:Ce3+ phosphors by co-doping with Gd3+ ions

Y3Al5O12:Ce3+, Gd3+ (YAG:Ce3+, Gd3+) phosphors were synthesized by a high-energy ball milling method. The X-ray diffraction (XRD) patterns showed their garnet structure, and several diffraction peaks shifted to lower angle side when co-doped with Gd3+ ions. Field emission scanning electron microscopy images exhibited irregular spherical particles of about 2 μm size. The photoluminescence (PL) properties of the YAG:Ce3+, Gd3+ phosphors were studied as a function of the Gd3+ ion concentration. The PL excitation (PLE) spectra exhibited the broad-band 4f–5d transition of Ce3+ ions centered at 439 nm. The PL spectra showed the intense 5d–4f transition of the Ce3+ ions with a band maximum at 542 nm, and this band maximum shifted to the longer wavelength region by increasing concentration of the Gd3+ ion.