title: Light-driven transformation processes of anisotropic silver nanoparticles.
abstract: The photoinduced formation of silver nanoprisms from smaller silver seed particles in the presence of citrate anions is a classic example of a photomorphic reaction. In this case, light is used as a convenient tool to dynamically manipulate the shape of metal nanoparticles. To date, very little is known about the prevailing reaction mechanism of this type of photoreaction. Here we provide a detailed study of the shape transformation dynamics as a function of a range of different process parameters, such as photon energy and photon flux. For the first time, we provide direct evidence that the photochemical synthesis of silver nanoprisms from spherical seed nanoparticles proceeds via a light-activated two-dimensional coalescence mechanism. On the other hand, we could show that Ostwald ripening becomes the dominant reaction mechanism when larger silver nanoprisms are grown from photochemically synthesized smaller nanoprisms. This two-step reaction proceeds significantly faster and yields more uniform, sharper nanoprisms than the classical one-step photodevelopment process from seeds. The ability to dynamically control nanoparticle shapes and properties with light opens up novel synthesis avenues but also, more importantly, allows one to conceive new applications that exploit the nonstatic character of these nanoparticles and the ability to control and adjust their properties at will in a highly dynamic fashion.
authors.affiliation: Department of Materials Engineering, Faculty of Engineering, Monash University, Clayton 3800, Victoria, Australia.
authors.forename: George P
authors.initials: GP
authors.lastname: Lee
authors.forename: Yichao
authors.initials: Y
authors.lastname: Shi
authors.forename: Ellen
authors.initials: E
authors.lastname: Lavoie
authors.forename: Torben
authors.initials: T
authors.lastname: Daeneke
authors.forename: Philipp
authors.initials: P
authors.lastname: Reineck
authors.forename: Ute B
authors.initials: UB
authors.lastname: Cappel
authors.forename: David M
authors.initials: DM
authors.lastname: Huang
authors.forename: Udo
authors.initials: U
authors.lastname: Bach
mesh_terms: D016880:Anisotropy; D003198:Computer Simulation; D008027:Light; D008422:Materials Testing; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000528:radiation effects*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation / Q000528:radiation effects; D010316:Particle Size; D010777:Photochemistry / Q000379:methods*; D012834:Silver / Q000737:chemistry* / Q000528:radiation effects*; D013499:Surface Properties / Q000528:radiation effects
chemical_list: D012834:Silver