title: Size-controlled synthesis and characterization of thiol-stabilized gold nanoparticles.
abstract: Size-controlled synthesis of nanoparticles of less than a few nanometers in size is a challenge due to the spatial resolution limit of most scattering and imaging techniques used for their structural characterization. We present the self-consistent analysis of the extended x-ray absorption fine-structure (EXAFS) spectroscopy data of ligand-stabilized metal nanoclusters. Our method employs the coordination number truncation and the surface-tension models in order to measure the average diameter and analyze the structure of the nanoparticles. EXAFS analysis was performed on the two series of dodecanethiol-stabilized gold nanoparticles prepared by one-phase and two-phase syntheses where the only control parameter was the gold/thiol ratio xi, varied between 6:1 and 1:6. The two-phase synthesis resulted in the smaller particles whose size decreased monotonically and stabilized at 16 A when xi was lowered below 1:1. This behavior is consistent with the theoretically predicted thermodynamic limit obtained previously in the framework of the spherical drop model of Au nanoparticles.
authors.affiliation: Physics Department, Stern College for Women, Yeshiva University, New York, New York 10016, USA. anatoly.frenkel@yu.edu
authors.forename: A I
authors.initials: AI
authors.lastname: Frenkel
authors.forename: S
authors.initials: S
authors.lastname: Nemzer
authors.forename: I
authors.initials: I
authors.lastname: Pister
authors.forename: L
authors.initials: L
authors.lastname: Soussan
authors.forename: T
authors.initials: T
authors.lastname: Harris
authors.forename: Y
authors.initials: Y
authors.lastname: Sun
authors.forename: M H
authors.initials: MH
authors.lastname: Rafailovich