title: Chemometric and microscopic analyses for the size growth of monolayer-protected gold nanoparticles during their superlattice formation.
abstract: Superlattices of gold nanoparticles have been produced at an air/solution interface under a highly acidic condition. The nanoparticle surface is protected by N-acetylglutathione (NAG). During the course of the superlattice formation, size growth of nanoparticles was observed: The superlattices were composed of nanoparticles of 6.6 nm in core diameter, whereas the as-prepared nanoparticles had the core diameter of 1.4 nm. The growth kinetics was pursued by the time evolution of the UV-vis absorption spectra for the sample solution. The change in the absorption spectral profiles was so small that we conducted principal-component analysis (PCA), which is known as a chemometric technique to resolve (or extract) spectra of minute chemical species submerged in the original spectra. Scanning transmission electron microscopy (STEM) corroborated the PCA results, yielding a successful explanation of the growth scheme of the NAG-protected gold nanoparticles.
authors.affiliation: Graduate School of Material Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan. yao@sci.u-hyogo.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yao
authors.forename: Keita
authors.initials: K
authors.lastname: Moriyama
authors.forename: Keisaku
authors.initials: K
authors.lastname: Kimura