Origin of the discrepancy between photoluminescence brightness of TAG:Ce and electroluminescence brightness of TAG:Ce-based white LED expected from phosphor brightness.
A yellow-emitting Tb(3)Al(5)O(12):Ce(3+) (TAG:Ce) phosphor was coated on blue light-emitting diodes (LEDs) to obtain white LEDs (WLEDs). Since TAG:Ce showed 90% of the brightness of Y(3)Al(5)O(12):Ce(3+) (YAG:Ce), it was expected that TAG:Ce-based WLEDs showed 90% of brightness of YAG:Ce-based ones. However, the TAG:Ce-based WLED showed 74% of the brightness of YAG:Ce-based one. Considering the density and size of the phosphors, the higher density and larger size of TAG:Ce induced a great deal of sedimentation of TAG:Ce particles in an epoxy resin. It is believed that this is one of main reasons for the reduced optical power of the TAG:Ce-based WLED compared to that of the WLED expected from the brightness of TAG:Ce.
Jang
Ho Seong
HS
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon, South Korea.
Kang
Jong Hyuk
JH
Won
Yu-Ho
YH
Chu
Kun-Mo
KM
Jeon
Duk Young
DY