Styryl Cyanine Dyes: Aggregate Behaviour, Electrochemical Properties and Photographic Performance

Abstract

The aggregate behaviour of styryl cyanine dyes on silver halide emulsions was investigated by measuring ultraviolet (UV)-visible (Vis) absorption spectra and reflectance spectra. The lowest vacant and the highest occupied electronic energy levels of these dyes were estimated using their redox potentials. The effects of styryl cyanine dyes upon the ionic conductivity of cubic silver halide grains with an average size of 0.18 μm in photographic emulsions have been studied with the aid of dielectric loss measurements. The ionic conductivity of the grains was increased by the adsorbed dye 2-(4′-diethylaminostyryl)-3-sulpho-propn/l-5-methoxybenzothiazole. The photographic performance in silver halide emulsion was examined and the correlation of photographic performance with electrochemical properties was studied. The experimental results indicate that the electrochemical properties of the dyes depend on their structure and the photographic performance of the dyes is determined by their electrochemical properties.