Abstract
A layer-by-layer method is used to coat silica on the red phosphor powders of Y 2 O 2 S:Eu in aqueous solutions. A cationic polymer of polyethylenimine (PEI) is used to form the first-layer coating, and the precipitating sodium silicate solution, to form negatively charged silica film on the PEI-coated phosphor powder as the second-layer coating. Repetition of the above coating process in aqueous solutions, a uniform, multiple silica/PEI bilayer coating on phosphor powder is formed.