Synthesis and luminescent properties of Sr4Al14O25:Eu2+ blue-green emitting phosphor for white light-emitting diodes (LEDs)

An efficient blue-green emitting phosphor, Sr4Al14O25:Eu2+, was prepared by solid-state reaction. X-ray powder diffraction (XRD) analysis confirmed the formation of Sr4Al14O25:Eu2+. Field-emission scanning electron-microscopy (FE-SEM) observation indicated that the microstructure of the phosphor consisted of irregular fine grains with an average size of about 8-10 mu m. Photoluminescence measurements showed a broad absorption band between 300 and 450 nm which was efficiently excited by near-ultraviolet (NUV) LEDs (350-410 nm) and a strong emission band peaking at 491 nm. A bright blue-green LED with chromatic coordination (0.176, 0.412) was fabricated by incorporating the phosphor with an InGaN-based NUV chip, which indicates that Sr4Al14O25:Eu2+ is a good candidate phosphor for application in white LEDs.