BaY1·95Al2Ga2SiO12:0.05Ce3+: A novel green-emitting phosphor with extra-high quantum yield, small thermal quenching and excellent water resistance for high-color-rendering white LEDs

It is well known that green-emitting phosphor plays a key role in a phosphor-converted white LED with high color rendering index. Here, a novel green phosphor BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ with high quantum yield , low thermal quenching and excellent water resistance is reported. The green phosphor can be easily prepared by the conventional solid-state reaction method at 1325 °C for 4 h in a reducing atmosphere. The compound is cubic and crystallizes in space group I a 3 ‾ d $Ia\bar{3}d$ with refined lattice parameters of a = 12.1451(3) Å. The phosphor can be effectively excited by the mainstream commercial blue LEDs (445–465 nm), its emission peak is observed at 517 nm and the absolute quantum yield under 450 nm excitation is as high as 96.2% at 25 °C. The green phosphor exhibits good resistance toward thermal quenching, with the luminescence intensity at 150 °C only decreasing by 11% of the value at 25 °C. In addition, the green phosphor has a very good water resistance, and its luminescence intensity remains almost unchanged when it is soaked in water for more than 300 h. The white LED fabricated by employing the green phosphor shows excellent optical properties with Ra = 92.4, CCT = 3304 K and CIE 1931 chromaticity coordinates as (x = 0.4178, y = 0.3985). All experimental results indicate that BaY 1·95 Al 2 Ga 2 SiO 12 :0.05Ce 3+ is an outstanding green phosphor which has great potential to be used for the phosphor-converted white LEDs with excellent color rendering.