Abstract
The formation of gold nanoparticles with the gold deposition development was investigated by altering the concentration of the gold(I) com- plex (AC) and ascorbic acid (AcA) solutions or their concentration ratio AC/AcA in the developer with three methods: absorption spectrum measurement, atomic absorption spectroscopy and transmission electron microscopy. Several phenomena, such as the variation in the devel- opment rates, existence of an induction period in the development rates, shift in the wavelength of maximum absorption, expansion of the band width, simultaneous formation of silver atoms, and change in the smoothness of the particle surface, were observed. These phenomena depended not only on the concentration of both solutions but significantly on their ratio. All these phenomena changed at a concentration ratio equal to unity, and it was suggested that the formation process varied at approximately this ratio. A novel process, whereby silver halide was reduced by excess AcA to form silver atoms and these atoms subsequently reduced gold ions to form gold atoms, was proposed to explain the acceleration of the development rates, the disappearance of the induction period, red-shift and expansion of the band, as well as the ap- pearance of a rough surface on the particles.
https://ror.org/01hjzeq58 
