(Ba,Sr)Y2Si2Al2O2N5 : Eu2+: a novel near-ultraviolet converting green phosphor for white light-emitting diodes

Abstract

A highly intense green-emitting phosphor BaY₂Si₂Al₂O₂N₅ : Eu²⁺ (BYN : Eu²⁺) peaking at 511 nm was synthesized by a solid state reaction. The structure refinement, luminescence properties of BYN : Eu²⁺ phosphors as well as their thermal quenching and the fabrication of white-light-emitting diodes (W-LEDs) were firstly investigated. By partially substituting Ba by Sr, namely (Ba,Sr)Y₂Si₂Al₂O₂N₅ : Eu²⁺ (BSYN : Eu²⁺), the emission peak was shifted to 565 nm, giving a yellow-orange color, due to the splitting of the 5d energy level. By utilizing a mixture of blue-emitting BaMgAl₁₀O₁₇ : Eu²⁺, green-emitting BYN : Eu²⁺ and red-emitting CaAlSiN₃ : Eu²⁺ phosphors as light converters, an intense white GaN-based n-UV-LED (380 nm) was fabricated to a exhibit good color-rendering index R_a of 84.5 at a correlated color temperature of 5089 K and CIE coordinates of (0.3425, 0.3478). Based on these results, we are currently evaluating the potential application of BYN : Eu²⁺ as a green-emitting near-UV convertible phosphor.