Journal of the American Ceramic Society, Vol.101, No.7, 2914-2920, 2018
Eu3+-doped glass as a color rendering index enhancer in phosphor-in-glass
A new method for improving color rendering index (CRI) and low correlated color temperature (CCT) in high-power white-light-emitting diodes (WLEDs) is proposed. We used a configuration of phosphor-in-glass (PIG) and studied light output changes with the increment in concentration of yellow-emitting Y3Al5O12:Ce3+ (YAG:Ce3+) phosphor. The PIG was coupled on the top of blue-light-emitting diodes (LED) chip (465nm). To compensate the lack of red emission in the phosphor, Eu3+-doped tellurium glass with different europium content was employed as a red emitter. The suitable contents of YAG:Ce3+ and Eu3+ were 7.5 weight percent (wt%) and 3mol percent (mol%), respectively. The CRI value went from 72 to 82, whereas the CCT was reduced from 24933 to 6434K. The proposed structure can improve CCT as well as CRI of WLEDs just by placing a glass on top.