Highly luminescent yttria–silica core–shell nanoparticles by the sacrificial polymer shell method

This paper describes the correlation existing between the photoluminescence of core–shell SiO2@Y2O3:Eu3+ nanoparticles synthesised by a method based on a sacrificial polymer-shell intermediate, and the thickness of that polymer shell. The method is based on the synthesis of a covalently bonded sacrificial polymer shell by polymerization of methacryl oxyethyl isocyanate (MOI) onto silica cores; the polymer shell was demonstrated to act as a promoter and stabilizer of the adsorption of yttrium and europium ions on the surface of silica, and its thickness plays an important role on the final luminescent intensity of the hybrid particles, which is related to the adhesion and continuity of the lanthanide shell of SiO2@Y2O3:Eu3+ nanoparticles. Yttria shells were obtained with thickness varying in the range 3–20 nm by tuning the polymer shell thickness in the range 0–50 nm. Results demonstrate that photoluminescence of SiO2@Y2O3:Eu3+ nanoparticles prepared via the sacrificial polymer shell method is much higher with respect to nanoparticles obtained by a traditional procedure.