title: A generalized ligand-exchange strategy enabling sequential surface functionalization of colloidal nanocrystals.
abstract: The ability to engineer surface properties of nanocrystals (NCs) is important for various applications, as many of the physical and chemical properties of nanoscale materials are strongly affected by the surface chemistry. Here, we report a facile ligand-exchange approach, which enables sequential surface functionalization and phase transfer of colloidal NCs while preserving the NC size and shape. Nitrosonium tetrafluoroborate (NOBF4) is used to replace the original organic ligands attached to the NC surface, stabilizing the NCs in various polar, hydrophilic media such as N,N-dimethylformamide for years, with no observed aggregation or precipitation. This approach is applicable to various NCs (metal oxides, metals, semiconductors, and dielectrics) of different sizes and shapes. The hydrophilic NCs obtained can subsequently be further functionalized using a variety of capping molecules, imparting different surface functionalization to NCs depending on the molecules employed. Our work provides a versatile ligand-exchange strategy for NC surface functionalization and represents an important step toward controllably engineering the surface properties of NCs.
authors.affiliation: Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States. adong@lbl.gov
authors.forename: Angang
authors.initials: A
authors.lastname: Dong
authors.forename: Xingchen
authors.initials: X
authors.lastname: Ye
authors.forename: Jun
authors.initials: J
authors.lastname: Chen
authors.forename: Yijin
authors.initials: Y
authors.lastname: Kang
authors.forename: Thomas
authors.initials: T
authors.lastname: Gordon
authors.forename: James M
authors.initials: JM
authors.lastname: Kikkawa
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Murray
mesh_terms: D000097:Acetonitriles / Q000737:chemistry; D000497:Alloys / Q000737:chemistry; D001881:Borates / Q000737:chemistry; D002384:Catalysis; D003102:Colloids; D003979:Diazonium Compounds / Q000737:chemistry; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D004126:Dimethylformamide; D004563:Electrochemistry; D005559:Formamides / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D008024:Ligands; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D009569:Nitric Oxide / Q000737:chemistry; D010316:Particle Size; D010984:Platinum / Q000737:chemistry; D012995:Solubility; D013499:Surface Properties
chemical_list: D000097:Acetonitriles; D000497:Alloys; D001881:Borates; D003102:Colloids; D003979:Diazonium Compounds; D005559:Formamides; D008024:Ligands; C088437:nitrosonium tetrafluoroborate; D009569:Nitric Oxide; D010984:Platinum; D004126:Dimethylformamide; D004121:Dimethyl Sulfoxide; C032159:acetonitrile