Thermal stable cyan-emitting Ba9(Lu1.5Ga0.5)Si6O24:Ce3+for high color-rendering white LEDs

Cyan-emitting phosphors are key color converters for achieving a high color-rendering index (CRI) in white light -emitting diodes (LEDs). However, cyan phosphors that have a suitable excitation wavelength and high thermal stability are still challenges. In this work, the Ba9Lu1.5Ga0.5Si6O24:Ce3+ (BLGSO:Ce3+) cyan phosphor is studied. The excitation band has a peak at 395 nm, which is close to the emission light from the near-ultraviolet (NUV) LEDs (395-405 nm). BLGSO:Ce3+ manifests an emissive peak at 488 nm and a full-width at half maximum (FWHM) of 125 nm. Its internal quantum efficiency (IQE) reaches 90.7% at room temperature. At 150 degrees C, the cyan emission intensity decreases to 97.2% of the initial value at room temperature, indicating excellent thermal stability. Combining with CaAlSiN3:Eu2+ and the 395 nm chip, a white LED with a high CRI of 91.9 is achieved.