2-phosphor-converted white light-emitting diodes using oxynitride/nitride phosphors

Abstract
Green α - sialon : Yb 2 + and red Sr 2 Si 5 N 8 : Eu 2 + oxynitride/nitride phosphors have been demonstrated as potential downconversion luminescent materials for white light-emitting diodes(LEDs). In this letter, the authors attempt to fabricate white LEDs by combining α - sialon : Yb 2 + and Sr 2 Si 5 N 8 : Eu 2 + with a blue LED die and report their optical properties. These two phosphors lend themselves for use in 2-phosphor-converted white LEDs with promising properties: a wide range of tunable correlated colortemperature ( 2700 – 6700 K ) , acceptable color rendering index (82–83), and luminous efficacy ( 17 – 23 lm ∕ W ) . These LEDs are acceptable for general lighting.