The first solid-phase route to fabricate and size-tune gold nanoparticles at room temperature

Gold nanoparticles have attracted considerable interest due to their salient properties and many methods for their fabrication have been developed. In this study, for the first time a solid state method for their synthesis has been designed and developed. Thus, high-speed vibration milling has been used for the synthesis of gold nanoparticles, where sodium borohydride was used for the reduction of the gold salt. Poly(vinylpyrrolidone) was used as a protecting agent for the gold nanoparticles synthesized. This system used for the synthesis of the gold nanoparticles required only room temperature and yielded mostly polyhedral nanoparticles with diameters ranging from 6.3 ± 2.1 to 27.9 ± 6.2 nm. The size of the nanoparticles was tunable by varying different reaction parameters such as the molar mass of polymer protecting agent, reaction time, and the mass ratio of gold precursor and polymer protecting agent. The nanoparticles were characterized by UV-visible spectroscopy, Fourier transform-infrared spectroscopy, transmission electron microscopy, and powder X-ray diffraction techniques.