White light-emitting diodes of GaN-based Sr2SiO4:Eu and the luminescent properties

Abstract
We have synthesized a Eu 2+ -activated Sr 2 SiO 4 yellow phosphor and investigated an attempt to develop white light-emitting diodes(LEDs) by combining it with a GaN blue LED chip. Two distinct emission bands from the GaN-based LED and the Sr 2 SiO 4 : Eu phosphor are clearly observed at 400 nm and at around 550 nm, respectively. These two emission bands combine to give a spectrum that appears white to the naked eye. Our results showed that GaN (400-nm chip)-based Sr 2 SiO 4 : Eu exhibits a better luminous efficiency than that of the industrially available product InGaN (460-nm chip)-based YAG:Ce.
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