A simple way to prepare a hydrophobic Sr[LiAl 3 N 4 ]:Eu 2+ phosphor with improved moisture resistance

Abstract The red-emitting Sr[LiAl 3 N 4 ]:Eu 2+ (SLA) phosphor was synthesized under flowing N 2 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.