Synthesis and luminescence properties of Ce3+-doped Y3Al3.5Ga1.5O12 green phosphor for white LEDs

Abstract

A series of Ce3+-doped Y3Al3.5Ga1.5O12 green phosphors were successfully synthesized by a solid-state reaction method. The microstructure, morphology, luminescence spectra, luminescence quantum yield (QY) and thermal stability of the phosphor were investigated. The critical concentration of Ce3+ ions in Y3−mAl3.5Ga1.5O12:mCe3+ is m=0.06. The QY of Y2.94Al3.5Ga1.5O12:0.06Ce3+ phosphor is as high as 94% under excitation at 450nm and its luminescence intensity at 150°C still maintains 90% of that measured at 25°C, which are just a little worse than those of commercial Lu3Al5O12:Ce3+ green phosphor but much better than those of commercial (Sr,Ba)2SiO4:Eu2+ green phosphor. A white LED lamp was fabricated by employing Y2.94Al3.5Ga1.5O12:0.06Ce3+ as a green phosphor and commercial (Ca,Sr)AlSiN3:Eu2+ as a red phosphor (628nm), its Ra value, correlated color temperature (CCT), CIE1931 chromaticity coordinates and luminous efficiency is 84, 3081K, (x=0.4369, y=0.4142) and 102lm/W, respectively. The experimental results demonstrate that Y2.94Al3.5Ga1.5O12:0.06Ce3+ is a promising green phosphor not only can be used for high color rendering index white LEDs but also for high-power white LEDs.