Ca3Si2O4N2:Ce3+,Li+ Phosphor for the Generation of White-Light-Emitting Diodes with Excellent Color Rendering Index Values

Blue-emitting Ca3Si2O4N2:Ce3+,Li+ phosphors were successfully synthesized by solid-state reactions for applications in white near-ultraviolet (NUV) light-emitting diodes (LEDs) with excellent color rendering index (CRI) values. The excitation and reflectance spectra of these phosphors reveal broad excitation and absorption in the NUV region, which matches well with those of NUV chips. This phosphors showed a broad blue emission at 436-488 nm that is dependent on the concentration of Ce3+ and Li+ ions; the quantum efficiency of (Ca0.94Ce0.03Li0.03)(3)Si2O4N2 is 23.6% of that of the Ca-5(PO4)(3)Cl:Eu2+ phosphor. The thermal stability of the (Ca0.94Ce0.03Li0.03)(3)Si2O4N2 phosphor below 100 degrees C was higher than that of the commercially available Ca-5(PO4)(3)Cl:Eu2+ phosphor, and the activation energies were calculated to be 0.0445 and 0.0205 eV for the (Ca0.94Ce0.03Li0.03)(3)Si2O4N2 and Ca-5(PO4)(3)Cl:Eu2+ phosphors. The optical properties of the white NUV LED gave an excellent CRI of 92.5 with International Commission on Illumination (CIE) chromaticity coordinates of (0.338, 0.345) at a correlated color temperature (CCT) of 5266 K.