Toward the minimization of fluorescence loss in hybrid cross-linked core-shell PS/QD/PMMA nanoparticles: Effect of the shell thickness

We present an efficient method for the encapsulation and fixation of octadecylamine coated CdSe/ZnS quantum dots. This is achieved by incorporating the QDs into core-shell particles made of PS/DVB (core)/PMMA/DVB (shell) cross linked polymeric phases synthesized in two stages. The first stage comprises the production of a hybrid PS/DVB core with QD nanoparticles located at the interface of the polymer particle and aqueous phase. In the second stage a PMMA/DVB shell is produced on the hybrid cores, burying the QDs within the composite particle and substantially minimizing the migration of the QDs out of the particles. The stability of the QDs within the core-shell particles is proven by assessing the fluorescence over long periods of time. Contrary to what happens to the core particle dispersion that lost fluorescence in few weeks, the fluorescence emission of the core-shell particles preserves the optical properties of the neat QDs for more than 46 weeks.