Photoluminescent and oxygen sensing properties of core-shell nanospheres based on a covalently grafted ruthenium(II) complex

SiO2 nanospheres coated with silica chemically doped with a ruthenium complex [Ru(Bphen)(2)Phen-Si]Cl-2 (denoted as Ru, there Bphen = 4,7-diphenyl-1,10-phenanthrolin, Phen-Si = modified 1,10-phenathroline) were prepared using a simple solution based method. Field-emission scanning electron microscopy (FE-SEM) showed that the pure SiO2 nanospheres with a mean diameter of similar to 185 nm were successfully coated with Ru complex-chemically doped SiO2 shell with a thickness of similar to 45 nm. The obtained core-shell nanosphere materials exhibited bright red triplet metal-to-ligand charge transfer ((MLCT)-M-3) emission, and their photoluminescent intensity was sensitive to oxygen concentration. These propertiesmake them promising candidates for biomarkers and optical oxygen sensors, which can measure the O-2 concentration in biological fluids. Copyright (C) 2010 John Wiley & Sons, Ltd.