Optimization and temperature-dependent photoluminescence properties of yellow-orange emitting Sr sub(1.99) sub(-) sub(x) sub(-) sub(y)Ca sub(x)M sub(y)(Si sub(1) sub(-) sub(y)Z sub(y))O sub(4): 0.01Eu super(2+) (M = Y super(3+), K super(+), Z = Al super(3+), P super(5+)) phosphors for white light-emitting diodes

• Published in: Optical materials 2015-01, Vol.39, p.188-194
• Main Authors: Ci, Zhipeng, Sun, Mengxing, Li, Yao, Que, Meidan, Wang, Qian, Zhu, Ge, Wang, Yuhua
• Format: Article
• Language: English
• Subjects: Charge; Compensation; Doping; Emission; Excitation; Phosphors; Photoluminescence; Quenching; Spectra
• ISSN: 0925-3467
• DOI: 10.1016/j.optmat.2014.11.024

The yellow-orange phosphors Sr sub(1.99) sub(-) sub(x) sub(-) sub(y)Ca sub(x)M sub(y)Si sub(1) sub(-) sub(y) sub(y)O sub(4): 0.01Eu super(2+) (M = Y super(3+), K super(+), Z = Al super(3+), P super(5+), 0 [el] x [el] 0.9, 0 [el] y [el] 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 super(2+) plays an important role in the red-shift of the emission band in Sr sub(1.99) sub(-) sub(x)Ca sub(x)SiO sub(4): 0.01Eu super(2+). When the Ca super(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 sub(1.99) sub(-) sub(x)Ca sub(x)SiO sub(4): 0.01Eu super(2+) could serve as a red phosphor for the blue LEDs. The trace doping of Al super(3+) and P super(5+) with Y super(3+) and K super(+) as charge compensation significantly enhances the emission intensities of Sr sub(1.29)Ca sub(0.7)SiO sub(4): 0.01Eu super(2+). In addition, thermal properties of typical samples are also carefully investigated. A simple solid-state route was adopted to synthesize a series of phosphors Sr sub(1.99) sub(-) sub(x) sub(-) sub(y)Ca sub(x)M sub(y)(Si sub(1) sub(-) sub(y)Z sub(y))O sub(4): 0.01Eu super(2+). The PL spectra indicate that Ca super(2+) plays a significant role in enhancing red-emitting component. The trace doping of Al super(3+) and P super(5+) with Y super(3+) and K super(+) as charge compensation obviously enhances the emission intensities of Sr sub(1.29)Ca sub(0.7)SiO sub(4): 0.01Eu super(2+). Based on the configurational coordinate diagram, the thermal quenching phenomenon of typical samples is also reasonably explained.