Improvement of photoluminescence intensity of Ce-doped Y3Al5O12 phosphor by Si3N4 addition

• DOI: 10.1016/j.matchemphys.2017.02.035
• Publication Date: 2017-02-23T19:02:45Z
• Authors: Jiin-Jyh Shyu; Chia-Wei Yang
• Keywords: 02 engineering and technology; 0210 nano-technology; 7. Clean energy

Abstract Yttrium aluminum garnet (Y 3 Al 5 O 12 , YAG) has been widely used as a host for luminescent ions. The present paper describes the effects of Si 3 N 4 addition on the formation and photoluminescence properties of the Ce-doped YAG yellow phosphors. Phosphor powders with the nominal compositions of Y 2.95 Ce 0.05 Al 5- m Si m O 12- m N m ( m = 0–0.6) were prepared by calcining the mixed raw materials at 1500 °C in nitrogen atmosphere. X-ray diffraction, x-ray photoelectron spectroscopy, scanning electron microscope, and transmission electron microscopy equipped with an energy dispersive x-ray spectrometer were used to characterize the structure of the calcined powders. The photoluminescence properties were measured with fluorescence spectrophotometry. It was found that in the range of m = 0–0.27, single phase YAG solid solution (s.s.) in which the Y, Al, and O sites are partially occupied by Ce, Si, and N ions, respectively. The nitrogen ions do not distribute homogeneously over the YAG lattice. The tendency to bond with nitrogen ion for the cations is (Y, Ce) > Si > Al. With the increase in the Si 3 N 4 content, the increase in both the Ce 3+ /(Ce 3+ + Ce 4+ ) ratio and the Ce N bonds improve the intensity of the photoluminescent emission. At m = 0.27, the emission intensity reaches a maximum which is about 2.5 and 1.6 times of that for the Si 3 N 4 -free composition ( m = 0) calcined in air and nitrogen, respectively. When the Si 3 N 4 content ( m ) is higher than 0.27, the emission intensity decreases due to the existence of residual Si 3 N 4 phase.