A garnet-structured (Y, Ca)3(Al, Mg)2(Al, Si)3O12:Ce3+ phosphor-in-glass engineering for use in high color rendering white LEDs

Abstract

White light emitting diodes (LEDs) suffer from two most common drawbacks: the deficiency of the red component and the poor thermal stability of silicone. Ce3+-doped garnet phosphors with tailor-made luminescence properties can be achieved by variations in {A}, {B}, and {C} cation sites. Herein, a simultaneous ion co-substitution design strategy has been adopted to synthesize a series of (Y, Ca)3(Al, Mg)2(Al, Si)3O12 garnet phosphors and corresponding phosphor-in-glass (PiG) films. The co-substitution is finely restricted to the assigned sites. The emission peak is shifted from 529 to 565 nm, which is beneficial to obtain low color temperatures and high color rendering using a single phosphor for white LEDs. By employing the as-synthesized phosphor, the corresponding PiG films were fabricated by the low temperature co-sintering technology using the SiO2–B2O3–ZnO–Na2O glass system characterized with excellent thermal stability and moisture resistance. The morphological and elemental analyses demonstrated that the as-made phosphor powders were uniformly distributed in the glass host without any interfacial reactions. Finally, modular white LEDs with a high color rendering (Ra = 82.7) is achieved through the as-synthesized PiG film on an InGaN blue chip. This study may open up a facile approach to obtain high quality luminescence based on the mono-luminescence center, avoiding excitation energy wastage and low quantum efficiency aroused by multi-luminescence centers or color compensation phosphors in glass.