Elucidation and optimization of the exciton relaxation processes that result from the electronic structure of CdSe quantum dots (QDs) and their electronically coupled ligands are critically important for nanomaterial application in bioimaging, photocatalysis and light harvesting. Amine ligand interactions with CdSe QDs have been frequently examined since these neutral ligands bind relatively strongly, exhibit a dynamic adsorption/desorption stabilization and greatly influence photoluminescence. While there seems to be concurring evidence that increased amine coverage on the QD surface tends to yield improved optoelectronic properties, consistent thermodynamic profiles with suitably determined equilibrium constants are lacking. The most commonly recognized limitation in previous reports is the inability to directly analyze thermodynamic information for the QD–ligand interactions. We have developed a novel gel permeation chromatography purification technique that is used to provide reproducible, well-defined QD starting materials for the investigations of amine ligand interactions using isothermal titration calorimetry (ITC). ITC allows extremely sensitive characterization of the dynamics within the QD–ligand system without relying on a spectroscopic signature which may be indistinguishable or suppressed in such a complex equilibrium environment. This presentation will describe how ITC and common spectroscopic techniques can be used concomitantly to continue building a more mechanistic understanding of neutral ligand interactions with CdSe QDs.

Non-spectroscopically dependent study of neutral amine ligand binding interactions with CdSe quantum dots

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.