Nanocrystal synthesis with alkoxy reagents for dispersion in polar and non-polar solvents

Abstract

Applications of colloidal nanocrystals in polar solvents often require nanocrystals synthesized in non-polar solvents. However, solvent transfer processes are problematic and deteriorate nanocrystal quality. Here we report syntheses of nanocrystals with nearly universal solvent dispersibility using ligands and solvents with alkoxy repeating units. Core syntheses, shell deposition and cation exchange proceed similarly to traditional methods while products are more stable in aqueous solution than those generated by solvent transfer. (CdSe)CdZnS nanocrystals retain photoluminescence in cells for single-particle tracking experiments and outperform other nanocrystal classes in diffusion metrics reflecting stability and resistance to non-specific binding. Distinct reaction classes yield nanocrystals with either methoxy or hydroxy ligand terminations, both of which can be purified by aqueous methods that are chemically greener than traditional methods. These reactions can further generate nanocrystals with diverse oxide, sulfide and selenide compositions, shapes and spectral bands with wide dispersibility that may make applications in polar solvents more widely accessible. Nanocrystals are synthesized with long-term colloidal stability in both polar and non-polar solvents without the need for ligand exchange. During synthesis, conventional coordinating ligands and solvents with long alkyl chains are replaced with those bearing alkoxy repeating units.