Particle Size Effect on the Packaging Performance of YAG:Ce Phosphors in White LEDs


  • The authors thank the National Science Council (contract no. NSC 96-2120-M-002-019) and the Ministry for Economic Affairs (contract no. 96-EC-17-A-07-S1-043) for financial support.


The synthesis of cerium-doped yttrium aluminum garnet (YAG:Ce) phosphor of different sizes with uniform size distribution was carried out using solid-state reaction followed by grinding and sieving method. The effect of particle size distribution of YAG:Ce phosphors on the photoluminescence (PL) properties was investigated. The results demonstrate that the uniform size distribution and particle size affects the packaging performance in white light emitting diode (LED) applications. The YAG:Ce phosphors with different particle sizes were packaged in white LEDs using different amounts of each phosphors in order to get similar efficiency as that of commercially available YAG:Ce phosphors. It was observed that minimum amount of phosphor material is required for smaller particle size for getting the similar efficiency as that exhibited by commercially available YAG:Ce phosphors. The results are particularly interesting in view of reducing the cost of current LEDs by lowering the amount of phosphors without compromising the efficiencies of final LED package. A systematic study of YAG:Ce phosphors on the packing performance in white LEDs is reported.