Color tunable dual-phase transparent glass ceramics for warm white light-emitting diodes

Abstract

Currently, Ce³⁺:Y₃Al₅O₁₂ phosphor converted white light-emitting diodes suffer from a deficiency of adequate red components and easy aging of the organic silicone matrix. Herein, Ce³⁺/Mn²⁺/Si⁴⁺:Y₃Al₅O₁₂ phosphors were synthesized via a traditional solid-state reaction and they can emit intense red luminescence, which is attributed to the Mn²⁺:⁴T₁ → ⁶A₁ spin-forbidden transition under the excitation of blue light via efficient energy transfer from Ce³⁺ to Mn²⁺. Temperature-dependent emission spectra and luminescent decay curves evidence that Mn²⁺ activators partition into both the Al³⁺ octahedral and Y³⁺ dodecahedral sites, whereas the Si⁴⁺ sites located in the Al³⁺ tetrahedral site are charge compensators. Furthermore, inorganic Ce³⁺:Y₃Al₅O₁₂ and Ce³⁺/Mn²⁺/Si⁴⁺:Y₃Al₅O₁₂ dual-phase transparent glass ceramics were successfully fabricated via a low-temperature co-sintering technique to replace the phosphor in organic silicone as a color converter, and red to yellow tunable luminescence can be easily achieved by controlling the content of red phosphor in the glass matrix. Note that by combining the fabricated dual-phase glass ceramics with the InGaN blue chip, warm white light-emitting diodes with a superior optical performance and excellent heat-resistance stability were successfully constructed.