The Surface Chemistry of Colloidal Nanocrystals Capped by Organic Ligands
Jonathan De Roo
Abstract
Nanocrystal surface chemistry is a pivotal element in the synthesis and application of nanocrystals. This perspective focuses on colloidal nanocrystals, capped with organic ligands. We start with insights into a workhorse characterization technique: solution nuclear magnetic resonance (NMR) spectroscopy. We then discuss the different models used to conceptualize nanocrystal surface chemistry and how the classification of binding motifs helps in the prediction of surface reactions. The thermodynamics and kinetics of these surface reactions are analyzed, and we arrive at the deciding factors for a high binding affinity: sterics, pKa/pKb, and solubility/solvent. Finally, we discuss recent ligand designs; most notably we introduce a new ligand class: monoalkyl phosphinic acids.