Nature and Properties of Ultrathin Nanocrystalline Gold Films Formed at the Organic−Aqueous Interface

Abstract

Ultrathin nanocrystalline films of gold formed at different temperatures at the organic-aqueous interface have been investigated by X-ray diffraction, electron microscopy, atomic force microscopy, and electronic spectroscopy. The films are smooth and continuous over relatively large length scales and are generally approximately 100 nm thick. The size of the nanocrystals is sensitive to the reaction temperature, which also determines whether the film is metallic or an activated conductor. The surface plasmon band of gold is highly red-shifted in the films. Alkanethiols perturb the structure of the films, with the magnitude of the effect depending on the chain length. Accordingly, the position of the plasmon band and the electrical resistance of the films are affected by interaction with alkanethiols; the plasmon band approaches that of isolated nanocrystals in the presence of long-chain thiols.

Surfactant-promoted formation of fractal and dendritic nanostructures of gold and silver at the organic–aqueous interface

“…The optical absorption spectrum of the film containing these networks show plasmon bands. The 780 nm band can be considered to be due to the plasmon adsorption of the aggregates as described in the literature [27][28][29].…”

Use of the liquid–liquid interface for generating ultrathin nanocrystalline films of metals, chalcogenides, and oxides

“…9, we demonstrate how the intensity of the Au plasmon absorption band grows as a function of time [61]. UV-visible spectra were recorded by placing the film deposited on glass perpendicular to the beam in a quartz cuvette.…”

“…The image in Fig. 6a shows a boundary of the Au film on a mica substrate [61]. The height profile in Fig.…”

Synthesis and Characterisation of Nanomaterials

“…Further, the size of the metal nanocrystals formed at the liquid-liquid interface can be controlled by adjusting the various reaction parameters such as contact time, temperature, and concentration of the reactants. By this means, the optical and electrical properties of the films can be varied 20 .…”