A novel green phosphor Sr8ZnY(PO4)7:Eu2+, Ln3+ (Ln = Pr, Tm, Yb) with broad emission band for high color rendering white-lighting-emitting diodes

Green phosphor is an essential component in phosphor-converted white light-emitting diodes (pc-LEDs). Herein, a novel green-emitting phosphate phosphor Sr 8 ZnY(PO 4 ) 7 :Eu 2+ (SZYP:Eu 2+ ) was synthesized through hydrothermal reaction method. The crystal structure, photoluminescence properties as well as thermal stability of SZYP:Eu 2+ were investigated systematically. SZYP:Eu 2+ can be efficiently excited by n-UV light in the range from 220 to 550 nm and shows a broad emission band centered at 520 nm with a full width at half maximum of 86 nm. The optimized doping concentration of Eu 2+ was determined to be 0.02 mol. With the increase of Eu 2+ content, a subtle red shift about 4 nm in emission spectra was detected. SZYP:Eu 2+ also shows comparable thermal stability (45% at 150 °C) and it can be further varied to 44, 40 and 51% by co-doping with Pr 3+ , Tm 3+ and Yb 3+ , respectively. The white LED device blended with SZYP:Eu 2+ shows excellent electroluminescence (EL) properties. The low correlated color temperature (4791 K) and ultrahigh color rendering index (95.8) imply that this phosphor may find a potential application in high-quality white LEDs.