The properties of several solid state lighting phosphor compounds have been enhanced through the application of
advanced material processing and particle encapsulation techniques. Also higher light extraction efficiencies from the
pump LED were achieved by index-matching the refractive index of the phosphor to that of the InGaN chip. New solid-state-
reaction protocols have produced a significant increase in the intrinsic efficiency of the orthosilicate yellow
phosphor compared to the traditional YAG:Ce phosphor. In addition, the stability of phosphor materials in high humidity
environments was increased significantly using metal oxide coatings applied by vapor deposition.
A brief review is given of the development of phosphors for solid-state lighting and the properties of new materials that are being developed for this emerging technology to achieve higher efficiencies, full color rendition and ultra-long life characteristics.