Hyper-efficient quenching of a conjugated polyelectrolyte by dye-doped silica nanoparticles: better quenching in the nonaggregated state.

We investigated the quenching properties of poly(phenylene ethynylene) with anionic alkoxyl sulfonate side groups, PPE-SO3, by tris(2,2-bipyridyl)dichlororuthenium(II) (Rubpy)-doped silica nanoparticles (SiNPs) in water, methanol, and the surfactant Triton X-100 aqueous solution. SiNPs demonstrated hyper-efficient quenching characterized by the Stern-Volmer constants in the range of 10(9)-10(10) M(-1), which is about 100-10,000 times more efficient compared to the Rubpy dye. More importantly, quenching by SiNPs was found to be more efficient when the polymer existed as a nonaggregated state, such as in methanol solution and in the surfactant solution. Investigations on confocal fluorescence images and time-resolved fluorescence decays were carried out to study the quenching mechanism.