Luminescent properties of yellowish orange Y3Al5-xSixO12-xNx: Ce phosphors and their applications in warm white light-emitting diodes

This paper reports a low-cost yellow-orange emitting Y3Al5-xSixO12-xNx:Ce3+ phosphor with excellent color rendering for warm white LEDs. It was synthesized by a simple gas pressure sintering (GPS). The effect of Si4+-N3- incorporation on the optical properties of Y3Al5O12:Ce3+ phosphor was investigated. The addition of Si3N4 leads to an obvious shift of its emission spectra toward the red region and an increase of FWHM accompanying a significant decrease of photoluminescent intensity, which is assigned to incorporation of N3- in Ce3+ nearest neighbor coordination. Adding nanosized amorphous Si3N4 or flux can greatly improve the emission intensity of Y2.925Ce0.075Al5-xSixO12-xNx phosphor. Finally, the white LED flat lamp with a CRI as high as 83, luminous efficiency of 65 lm/W, and CCT of about 3700 K is successfully realized by using a single oxynitride phosphor combined with a blue LED chip, which is acceptable for general indoor illuminations to replace fluorescent or incandescent lamps. (c) 2012 Elsevier B.V. All rights reserved.