The synthesis of optically active nanostructures attracts researchers' interests due to their unique optical properties. Au and Ag nanostructures effectively interact with the light at the specific wavelength depending on their shapes. In terms of synthesizing Au nanoframes, most researchers select the galvanic replacement reaction on Ag nanoplates, but the structural weakness of thin Au ring easily induces aggregates.In my presentation, I will introduce an effective synthetic strategy to produce Au-coated Pt (Pt@Au) nanoframes. The Pt nanoring at the inner core acts as a framework, and Au coated on the Pt nanoring allows the nanostructure to behave optically active as pure Au nanoframes because of the surface plasmon coupling between Au and Pt. This research provides fundamental basis in order to understand the optical property of Au nanoframes.The experimental process consists of two regimes, etching and regrowth process. We adopt site-selective grown Au@Pt nanoplates as a seed, in which Pt selectively grow along the edge of Au nanoplates. We took advantage of rim-preferential growth synthetic method to finally synthesize Au nanorigs, through etching and regrowth processes.Au3+ ions in growth solution play a critical role as both of an etchant and a metal precursor. In the etching process, as Au plates at the central part is selectively etched out by Au3+ ions in absence of reductant, leaving only Pt rims. Pt-dominant nanorings are remained at the end of reaction. By adding ascorbic acid, a reducing agent, it initiates the regrowth of Au on Pt nanoring by reducing Au3+ ions present in the growth solution. The resultant product is in the form of Au-coated Pt nanoframes, which take advantage of the empty space among the nanoparticle, providing relatively high light transparency and reactant permeability in nano-optics and catalysis.

Fabrication of Au-coated Pt nanoframes via chemical etching and regrowth

248th National Meeting (2014)

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