Synthesis of quantum dots (QDs) requires a large amount of ligands to improve the stability at high temperature. However, for further application and surface modification of QDs, excess ligands must be removed. The traditional precipitation/ redissolution process cannot provide highly repeatable results due to: (1) variability in precipitation condition necessary for different QD batches (2) some impurities have similar polarity as the QDs. In this talk, I will describe using gel permeation chromatography (GPC) as a media to purify different types of QDs, including CdSe and CdSe/CdxZn1-xS QDs. 1H NMR and thermo gravimetric analysis (TGA) have been used to compare the nature and quantities of ligands adsorbed on the QDs after different purification methods. Here, inorganic shell growth and ligand exchange have been investigated as means to characterize the excess ligands' impact on further surface modification of QDs.

Purification of quantum dots by gel permeation chromatography and the effect of excess ligands on further surface modification

245th National Meeting (2013)

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