A versatile strategy for loading silica particles with dyes and quantum dots

A simple and inexpensive method for the controlled loading of silica particles with dyes and nanocrystals is presented. Polydiallyldimethylammonium chloride is used as a positively charged bridge to facilitate electrostatic adsorption of negatively charged dyes onto negatively charged silica microspheres. The particles are subsequently coated with a further silica shell to protect the dyes against chemical degradation and leakage and this shell affords a unform particle surface independent of its doping. This encapsulation method is highly versatile and can be extended to doping with semiconductor nanocrystals, which we demonstrate using CdSe/ ZnS core/shell quantum dots. The synthesis steps and end products are characterized with electron microscopy, optical spectroscopy and the electrokinetic potential of the colloidal suspensions. We show that the particles adapt the optical properties of their dopants and are resistant to degradation, dopant leakage and show reasonable emission even at acidic pH values due to the protective shell.

Automated summary

This paper presents a simple and inexpensive method for loading silica particles with dyes and nanocrystals. It utilizes polydiallyldimethylammonium chloride as a positively charged bridge to facilitate the electrostatic adsorption of negatively charged dyes onto negatively charged silica microspheres. The encapsulation method includes the subsequent coating of the particles with a silica shell to protect the dyes from degradation and leakage.