Improving Optical Properties of White LED Fabricated by a Blue LED Chip with Yellow/Red Phosphors

White light-emitting diodes (LEDs) were fabricated by associating an InGaN-based blue LED chip with highly luminescent phosphors, Y3Al5O12:Ce3+ (YAG:Ce) and CaSiAlN3:Eu2+. The thermal stability of these phosphors, depending weakly on the composition and the activator concentration, remains high over a wide range of temperatures (25-300 degrees C). When a mixture of YAG:Ce and CaSiAlN3:Eu2+ was coated on a blue LED, the resultant white LED had a high luminous efficiency of eta(L) = 68 lm/W, a high color rendering index of Ra = 93, and a color temperature of T-C = 3007 K (at 50 mA). Additionally, the color coordinates, Ra and T-C, of the white LED tend to remain constant against an appreciable variation in applied current. (C) 2010 The Electrochemical Society. [DOI:10.1149/1.3465654] All rights reserved.