Self-Organization of Nanosized Gold Particles

Abstract

Naked" colloidal gold solutions have been prepared in toluene using a two-phase system. The phase-transfer reagent used, a quaternary ammonium bromide salt (R 4 N + Br -), is specifically adsorbed on the clusters through the formation of surface ion pairs, probably with the Brion attached to the Au surface. The separation between clusters for two-dimensional structures is dependent on the chain length in R 4 N + . When more than one layer is present, the nanosized particles show unusual self-organization properties: the occupancy of 2-fold saddle sites is preferred to that of 3-fold hollow sites, leading to linear and circular arrangements. It is proposed that this is due to the balance between local electrostatic repulsion and dispersion forces between the particles.

Synthesis of Zinc Sulfide Nanocrystals and Fabrication of Nanocrystal Superlattice

“…However, they are energetically less favorable than that of three-fold hollow sites under the interactions between van der Waals attraction and short-range steric repulsion of alkyl-chain. This stripe array may be attributed to a surface dipole-dipole interaction between R-S À -M þ dipoles 11) or the crystal habit of NCs.…”

Surface modification, functionalization and bioconjugation of colloidal inorganic nanoparticles

“…Owing to their smaller electron density, organic molecules provide only poor contrast in TEM and may be stained with heavy elements (Dubertret et al 2002); in addition, samples have to be prepared in a dry state for observation under vacuum and will thus differ from the natural colloidal state in solution, e.g. by interdigitated ligand molecules (Fink et al 1998).…”

Short-time preparation and electrochemical properties of a single layer of tetraoctylammonium bromide capped Au nanoparticles on dithiol self-assembled monolayer-modified Au electrode

“…Thus, immersion of thiol terminated SAMs into TOAB-AuNPs leads to the rapid immobilization of AuNPs. As suggested by Brust and co-workers [25], TOAB ions might be easily replaced upon the attachment of the thiol groups and dissolved into toluene.…”

“…TOAB-AuNPs were prepared in toluene by the reported two-phase method [25]. An aqueous solution of HAuCl 4 ·4H 2 O (500 mg in 40 mL) was mixed with a solution of TOAB in toluene (3.06 g in 100 mL).…”