Eu 21 -doped CaMgSi 2 O 6 phosphor was prepared by depositing mixed hydroxides of Ca, Mg, and Eu over spherical SiO 2 particles (300 nm) pre-coated with polycations (polyethyleneimine), followed by calcination at 12001C in a reducing atmosphere. The prepared phosphor showed intense blue emission, ascribable to the 4f 7 -4f 6 5d transition of Eu 21 . In contrast, the luminescence intensity of the phosphor was considerably decreased when prepared without polycations. It was suggested that negatively charged hydroxides are deposited on positively charged SiO 2 surfaces pre-coated with polycations through electrostatic selfassembly interaction. On calcination, the hydroxide shells react with the SiO 2 cores to produce Eu 21 :CaMgSi 2 O 6 .J ournal