This synthesis process produces gold nano-stars, plasmonic nanoparticles useful as photocatalysts for many applications. The gold nanoparticles market is expected to reach $6.33 billion by 2025; the nanoparticles are in large demand to improve medical diagnostics and treatments and to advance electronics. Due to their high absorption/scattering, gold nanoparticles can enhance photocatalytic reactions in biomedical sensing and in solar power conversion.
Researchers at the University of Florida have developed a process to synthesize star-shaped gold nanoparticles, a new shape not previously produced. This synthesis uses lower-powered visible light to form particles useful in many settings.
Low-power, light-driven synthesis of star-shaped gold nanoparticles applicable in many photochemical processes
The synthesis process involves mixing gold (Au) seed nanoparticles, surfactants (polyvinylpyrrolidone), hole scavenger (methanol), and shape-defining potassium iodide into an aqueous solution and shining light into it. At certain wavelengths (460 – 600 nm), the irradiation process excites the surface plasmon resonance of Au seeds, which generates hot electrons and hot holes. Iodide adsorbed on Au surface traps and localizes hot holes in the form of a gold-iodide species. The trapped holes etch the gold nanoparticles at all exposed surfaces, but exhibit the highest etching rate on less stable high-index edges, leading to the formation of anisotropic, plasmonic gold nano-stars with photocatalytic properties beneficial for many applications.