Preparation of Ag2Se QDs with excellent aqueous dispersion stability by organic coating with aqueous ATRP

In this article, water-dispersible Ag 2 Se quantum dots (QDs) were prepared by the facile and environmental-friendly method. In our approach, atom transfer radical polymerization (ATRP) was adopted in aqueous media to grow polymer chains from the surface of Ag 2 Se QDs. The aqueous ATRP allows the very mild synthetic conditions. In the present work, the polymerization reaction of methoxy[oligo(ethylene glycol)] methacrylate (OEGMA) was carried out at room temperature under aqueous conditions after the incorporation of 2-bromopropionyl moiety as the ATRP initiator on the surface of Ag 2 Se QDs by the ligand exchange method. OEGMA-coated Ag 2 Se QDs were successfully obtained without significant morphological change. The aqueous dispersion stability of OEGMA-coated Ag 2 Se QDs was compared with that of conventional water-dispersible Ag 2 Se QDs prepared by the simple modification with 11-mercaptoundecanoic acid. As a result, OEGMA-coated Ag 2 Se QDs showed the extremely high aqueous dispersion stability.