Advancing interfacial engineering in energy materials by the deuteration of ligand shells in colloidal nanocrystal quantum dots

Colloidal nanocrystal quantum dots (“QD”) are integral components in optoelectronic devices and energy harvesting materials. They are inorganic nanocrystals a few nanometres in diameter coated with an organic ligand shell. The ligand shell controls the electronic and physical-chemical properties of the QD interface, providing solubility and colloidal stability. In designing functional optoelectronic materials, it can be advantageous to swap the native organic ligands, typically molecules of oleic acid which have formed oleates on the QD surface, for “active ligands” with desired electronic properties. SANS is a uniquely powerful tool to gain quantitative information about the physical composition of the ligand shell. In our wider research we wish to understand the mechanism and results of ligand exchange procedures. The aims of this experiment are to demonstrate QD with a finely controlled range of deuteration states in the ligand shell, and to confirm this composition using SANS. SANS is uniquely sensitive to QD structure. In the proposed experiment, we will exploit the ISIS SANS instruments’ excellent signal-to-noise and resolution coupled with the MIT group’s advanced QD modelling procedures and insights into QD processing to gain the most accurate picture to date of ligand shell structure in lead sulfide-oleic acid QD. This work will provide a platform for a wide range of new research directions in the QD community.