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, Y3A l5O12: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°C). When a mixture of YAG:Ce and CaSiAlN 3: Eu2+ was coated on a blue LED, the resultant white LED had a high luminous efficiency of νL = 68 lm/W, a high color rendering index of Ra = 93, and a color temperature of TC = 3007 K (at 50 mA). Additionally, the color coordinates, Ra and TC, of the white LED tend to remain constant against an appreciable variation in applied current.