Synthesis And Luminescence Properties Of Phosphates For White LEDs

Phosphate phosphors have been attracting more and more attentionsfor its good luminescence properties and stability. In this study, Ba3P4O13:xEu3+、 Sr3P4O13: xEu and Ba3P4O13: xEu2+phosphors were prepared byhigh temperature solid state method, and their photoluminescenceproperties were investigated.1. A new orange–red Ba3P4O13:Eu3+phosphor has been synthesized bysolid-state technique, and its photoluminescence properties wereinvestigated. X-ray powder diffraction (XRD) analysis indicates thatdoping Eu3+does not change the lattice of Ba3P4O13. Field-emissionscanning electron microscope (FE-SEM) images illustrate thatmicrostructure of the phosphor consists of oval grains with averagediameter of1μ m and heavy agglomerate phenomenon. The excitationspectra indicate the phosphor can be effectively excited by near ultraviolet(NUV) light, making it attractive as conversion phosphor for LEDapplications. The phosphor exhibits a bright orange–red emission excitedby394nm light. The CIE chromaticity can be varied slightly by adjustingthe content of Eu3+, which is attributed to the different lattice sitesoccupied by Eu3+in Ba3P4O13host. The photoluminescence studiesindicate that Ba3P4O13:Eu3+is a potential orange–red phosphor fornear-ultraviolet InGaN-based white light-emitting diodes (WLEDs).2. A new orange–red phosphor Sr3P4O13: Eu was synthesized by a hightemperature solid-state reaction. X-ray powder diffraction (XRD) analysiscon rms the formation of Sr3P4O13in a triclinic system with space groupP1. The photoluminescence spectra indicate that Sr3P4O13: Eu can beexcited effectively by near ultraviolet (NUV) light and exhibit bright orange–red emission with excellent color stability. Interestingly, theemission bands of Eu2+and Eu3+were both observed in thephotoluminescence spectra of air-sintered Sr3P4O13: Eu phosphor due tothe self-reduction effect. This kind of abnormal reduction was explainedby a charge compensation model.3. A new blue–green Ba3P4O13:Eu2+phosphor has been synthesized bysolid-state technique, and its photoluminescence properties wereinvestigated. The phosphor exhibits a wide emission between400nm and600nm excited by394nm light.