Preparation of Gold Nanoparticles in a Gelatin Layer Film Using Photographic Materials (5): Characteristics of Gold Nanoparticles Prepared on an Ultrafine Grain Photographic Emulsion

摘要

The authors report a process for the preparation of gold nanoparticles in a gelatin layer. This process is similar to the photographic process of gold development or gold latensification, where gold atoms are deposited on the exposed area of photographic material when it is immersed in a gold(l) thiocyanate complex solution. Gold particles have gained prominence for their nonlinear optical effect, the intensity of which depends on the density of the particles in the layer. The authors attempted to condense the particles using a photographic plate for hologram recording; this plate was made of an ultrafine grain emulsion because this emulsion was believed to be conducive to condensation. The characteristics of the particles were analyzed using photographic characteristic curves, absorption spectra, and size distributions. The characteristic curves rose gradually with the immersion period and finally showed a very high contrast curve. A sharp and strong plasmon absorption was observed at around 550 nm at high exposure values, while the peak exhibited a redshift and broadening at lower exposure values. The diameter of the particle increased proportionally with the square root of the immersion period. The growth rate decreased with the exposure value and was larger with high intensity exposure. The dependence on the exposure value was explained by the competition for the gold ion due to the high density of latent image specks. The larger growth rate with high intensity exposure was also explained by the low density of the latent image specks due to high intensity reciprocity failure.