Quantum Dot Functionalization Through Surface Ligand Reactions
Milo Sack
Department of Chemistry & Biochemistry
Faculty Supervisor: Michael Enright
Quantum dots (QDs) are typically made with non-polar, long-chain fatty acids as ligands that readily allow for size, shape, and structure control as the QDs grow, However, these ligands are usually not useful or even detrimental to using the QDs for applications in lighting and catalysis. The ligands are commonly replaced to better functionalize the QDs for desired reactions. These exchange reactions, however, have thus far been unsuccessful when using ZnS and CuAlS₂/ZnS QDs, compelling us to develop new functionalization approaches by designing chemical reactions that target the surface ligands to convert them into new, functionalized surfaces.Our work aims to replace native ligands on non-polar QDs, such as ZnS and CuAlS₂/ZnS core-shelled quantum dots, which typically do not cooperate with biphasic ligand exchange. Through characterization techniques such as Atomic Force Microscopy (AFM) for measuring particle sizes, Scanning Transmission Electron Microscopy (STEM) for assessing morphology, UV-Vis spectroscopy to measure colloidal stability based on absorbance, and Fourier Transform Infrared (FTIR) and Nuclear Magnetic Resonance (NMR) spectroscopies to monitor changes in chemical composition, we evaluate the efficiency and stability of the ligand conversion reactions to bring our QDs into polar solvents, expanding the potential applicability of QDs by providing a new pathway for surface functionalization.