Design of a CaAlSiN₃:Eu/glass composite film: Facile synthesis, high saturation-threshold and application in high-power laser lighting

Even though CaAlSiN3:Eu2+ (CASN) is, in many regards, a highly suitable red phosphor that can be used in white light-emitting diodes, it can hardly be used in high-power laser-lighting because of its low saturation-threshold. By using CASN-based composite ceramics, it is possible to increase the threshold but new difficulties appear. These include complex and expensive synthesis, while the saturation-threshold still has room for improvement. In this study, we prepare a CASN/glass composite film, using an industry-friendly blade-coating method. The film has a high internal quantum efficiency of 79%, which suggests low conversion loss. Under 1.17 W blue laser excitation, a high luminous efficacy of 21.0 lm/W can be obtained. More importantly, the composite film shows a record-high saturation-threshold of more than 12.7 W ( similar to 320 W/cm(2)) blue laser excitation. With these outstanding properties, CASN/glass composite films may open doors towards commercially viable red color converters for high-power laser-lighting applications.