A simple way to prepare a hydrophobic Sr[LiAl3N4]:Eu2+ phosphor with improved moisture resistance

Highlights: • A simple modification method to transform SrLiAl₃N₄:Eu²⁺ into hydrophobic phosphor. • A thin organosilica layer (about 5–10 nm) was coated on the surface of SLA phosphor. • The modified phosphor features superior stability under extremely environment. - Abstract: The red-emitting Sr[LiAl₃N₄]:Eu²⁺ (SLA) phosphor was synthesized under flowing N₂ gas. A thin organosilica layer (about 5–10 nm) was coated on the surface of SLA phosphors by a very simple method, which transformed the phosphor surface from hydrophilicity to hydrophobicity. The contact angle of water droplets on the surface of the packed SLA phosphors was more than 140°. Compared with the unmodified sample, the modified SLA phosphors could keep at a high emission intensity for more than twice the time under an extremely high moisture level (at relative humidity of 100%, 85 °C). The hydrophobic modification could also improve the uniform dispersion of phosphors during assembly process of white LED.