Synthesis and characterization of water-soluble, stable and highly luminescent itaconic acid/methacrylic acid copolymer-coated CdSe/CdS quantum dots

Abstract The itaconic acid/methacrylic acid (PIA–MAA) copolymer ligand (PIA–MAA) with carboxylate anchoring groups was found to efficiently convert CdSe/CdS core–shell quantum dots (QDs) in chloroform to water-soluble PIA–MAA-ligand stabilized nanocrystals (PIA–MAA-QDs). The quantum yield (QY) of the resulting PIA–MAA-QDs was 24%. In addition, the carboxylate-based PIA–MAA-QDs survived UV irradiation in air for at least 16 days. Upon UV irradiation, the PIA–MAA-QDs became about 2 times brighter than the original CdSe/CdS QDs in chloroform, and the UV-brightened photoluminescence (PL) can retain the brightness for at least several months. Experimental results further confirmed that the PIA–MAA-QDs were more stable than the original CdSe/CdS QDs against strong acid, strong oxidant, photochemical and thermal treatments. The PIA-MAA-QDs were soluble and stable in water, some polar solvents and buffer solutions. In addition to good performance of PIA–MAA-QDs, the synthesis of PIA–MAA ligands and the corresponding water-soluble QDs is relatively simple.