title: Toward scatter-free phosphors in white phosphor-converted light-emitting diodes.
abstract: Scatter-free phosphors promise to suppress the scattering loss of conventional micro-size powder phosphors in white phosphor-converted light-emitting diodes (pc-LEDs). Large micro-size cube phosphors (~100 μm) are newly designed and prepared as scatter-free phosphors, combining the two scatter-free conditions of particles based on Mie's scattering theory; the grain size or grain boundary was smaller than 50 nm and the particle size was larger than 30 μm. A careful evaluation of the conversion efficiency and packaging efficiency of the large micro-size cube phosphor-based white pc-LED demonstrated that large micro-size cube phosphors are an outstanding potential candidate for scatter-free phosphors in white pc-LEDs. The luminous efficacy and packaging efficiency of the Y(3)Al(5)O(12):Ce(3+) large micro-size cube phosphor-based pc-LEDs were 123.0 lm/W and 0.87 at 4300 K under 300 mA, which are 17% and 34% higher than those of commercial powder phosphor-based white LEDs (104.8 lm/W and 0.65), respectively. In addition, the introduction of large micro-size cube phosphors can reduce the wide variation in optical properties as a function of both the ambient temperature and applied current compared with those of conventional powder phosphor-based white LEDs.
authors.affiliation: Department of Chemistry, Kookmin University, Seoul 136-702, South Korea.
authors.forename: Hoo Keun
authors.initials: HK
authors.lastname: Park
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Oh
authors.forename: Young Rag
authors.initials: YR
authors.lastname: Do
mesh_terms: D003116:Color; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008029:Lighting / Q000295:instrumentation*; D012666:Semiconductors