Improvement of the thermal stability of bluish-cyan emitting phosphor Y2MgAl4SiO12:Eu2+ using substitution cations (Zn, Ca, Sr) for white LEDs

A series of bluish-cyan color adjustable phosphors Y2MgAl4SiO12:xEu2+(YMAS) and Y2(Mg1-y,My)Al4SiO12:Eu2+ (M=Zn, Ca, Sr) were synthesized by the solid-state method. The thermal stability can be improved by modifying cation, especially, the thermal stability of Y2MgAl4SiO12:Eu2+ at 150℃ was gradually improved to 92.34% of original luminescence intensity by introducing Sr2+. The white light emitting diode (LED) was fabricated by combining near ultraviolet (NUV) LED chip (370 nm) with a mixture of Y2Mg0.8Sr0.2Al4SiO12:0.01Eu2+ along with green (Ba, Sr)2SiO4:Eu and red CaSiAlN3:Eu in different proportions. A bright warm white LED gives a high color rendering index Ra=96.4, a low correlated color temperature CCT=4434K, and CIE chromaticity coordinates at (0.35, 0.34). The results demonstrate that Y2Mg0.8Sr0.2Al4SiO12:Eu2+ phosphor may be potential application in field of white LEDs.