Optimization and temperature-dependent photoluminescence properties of yellow–orange emitting Sr1.99−x−yCaxMy(Si1−yZy)O4: 0.01Eu2+ (M=Y3+, K+, Z=Al3+, P5+) phosphors for white light-emitting diodes

Abstract The yellow–orange phosphors Sr 1.99 − x − y Ca x M y Si 1 − y Z y O 4 : 0.01Eu 2+ (M = Y 3+ , K + , Z = Al 3+ , P 5+ , 0 ⩽ x ⩽ 0.9, 0 ⩽ y ⩽ 0.01) were synthesized by the solid state reaction. X-ray diffraction and photoluminescence spectra were utilized to characterize the samples. The results indicate that the phosphors can be efficiently excited by the UV–blue light and show a broad band emission from about 425 to 700 nm. Ca 2+ plays an important role in the red-shift of the emission band in Sr 1.99 − x Ca x SiO 4 : 0.01Eu 2+ . When the Ca 2+ concentration x = 0.7, the emission peak under the excitation of 450 nm reaches a maximum at about 600 nm, which implies that the samples Sr 1.99 − x Ca x SiO 4 : 0.01Eu 2+ could serve as a red phosphor for the blue LEDs. The trace doping of Al 3+ and P 5+ with Y 3+ and K + as charge compensation significantly enhances the emission intensities of Sr 1.29 Ca 0.7 SiO 4 : 0.01Eu 2+ . In addition, thermal properties of typical samples are also carefully investigated.