Surfactant‐Free Shape Control of Gold Nanoparticles Enabled by Unified Theoretical Framework of Nanocrystal Synthesis. Issue 21 (4th April 2017)

• Record Type: Journal Article
• Authors: Wall, Matthew A.; Harmsen, Stefan; Pal, Soumik; Zhang, Lihua; Arianna, Gianluca; Lombardi, John R.; Drain, Charles Michael; Kircher, Moritz F.
• Is Part Of: Advanced materials. Volume 29:Issue 21(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-04-04
• Subjects: crystal growth -- gold nanorods -- nanoparticles -- shape‐control -- surfactant‐free; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201605622
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract : Gold nanoparticles have unique properties that are highly dependent on their shape and size. Synthetic methods that enable precise control over nanoparticle morphology currently require shape‐directing agents such as surfactants or polymers that force growth in a particular direction by adsorbing to specific crystal facets. These auxiliary reagents passivate the nanoparticles' surface, and thus decrease their performance in applications like catalysis and surface‐enhanced Raman scattering. Here, a surfactant‐ and polymer‐free approach to achieving high‐performance gold nanoparticles is reported. A theoretical framework to elucidate the growth mechanism of nanoparticles in surfactant‐free media is developed and it is applied to identify strategies for shape‐controlled syntheses. Using the results of the analyses, a simple, green‐chemistry synthesis of the four most commonly used morphologies: nanostars, nanospheres, nanorods, and nanoplates is designed. The nanoparticles synthesized by this method outperform analogous particles with surfactant and polymer coatings in both catalysis and surface‐enhanced Raman scattering. Abstract : A new theoretical framework that identifies a surfactant‐free route to control the shape of nanoparticles is presented. For the first time, it is predicted and confirmed that gold nanorod formation in the absence of surfactants is driven by re‐entrant groove defects on the end facets. Nanoparticles synthesized by this approach demonstrate excellent surface‐enhanced Raman scattering and catalytic performance.