Crystal-Bound Ligands in Nanocrystal Synthesis

Abstract

Semiconductor nanocrystals are a desirable class of nanomaterials for electronic, energy conversion, and biomedical applications. The work presented in this thesis aids in the understanding of the fundamental chemistry that governs the way organic ligands coordinate to the surfaces of these nanocrystals. Using NMR, XPS, and TGA-MS a new binding mode of thiol ligands was identified on the surface of metal sulfide nanocrystals. This binding mode, crystal-bound ligands, has increased stability to removal compared to traditional surface-bound ligands. Taking advantage of the crystal-bound ligand coordination allows for the development of more active and potentially more stable photocatalysts. Overall, stabilizing the surface of a nanocrystal using crystal-bound ligands resulted in an enhancement in photocatalytic efficiency compared to a surface-bound ligand sample. Additionally, computational models of ligand coordination to surfaces were developed, providing new insights on the structural implications of ligand coordination.