Preparation and thermally stable luminescence properties of a new blue Sr5Cl0.75F0.25(PO4)3: Eu2+ phosphor for WLEDs

Abstract A series of new blue-emitting phosphors Sr 5(1− x ) Cl 0.75 F 0.25 (PO 4 ) 3 : 5 x Eu 2+ ( x  = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 mol%) were synthesized by high-temperature solid state reaction. X-ray powder diffraction (XRD) and field-emission scanning electron microscope (FE-SEM) were used to characterize the crystal structure and micro-morphology of the prepared samples. The photoluminescence properties of these phosphors were investigated by excitation and emission spectra. The effect of Eu 2+ concentration on emission of the phosphor was investigated and the concentration quenching mechanism was discussed in detail. Also, the temperature-dependence luminescence properties of Sr 5 Cl 0.75 F 0.25 (PO 4 ) 3 : Eu 2+ were compared with those of the commercial blue phosphor BaMgAl 10 O 17 : Eu 2+ (BAM). With the increase of temperature, the emission band exhibited blue shift and decreasing emission intensities. The phosphor Sr 5 Cl 0.75 F 0.25 (PO 4 ) 3 : Eu 2+ possesses higher thermal stability than BAM. Furthermore, a bright blue LED was fabricated by combination of n-UV InGaN chip and the phosphor. The results reveal that Sr 5 Cl 0.75 F 0.25 (PO 4 ) 3 : Eu 2+ is a potential blue phosphor for n-UV-pumped white light-emitting-diodes (WLEDs).