(Invited) Plasmon-Driven Photochemistry for the Synthesis of Metal Nanostructures

Abstract

Plasmon-driven photocatalysis with metal nanoparticles holds great promise for initiating and controlling chemical reactions at the nanoscale. One interesting application of plasmonic photochemistry involves the synthesis of metal nanostructures from cationic precursors. Despite more than twenty years of study however, this unique approach to material synthesis remains restricted to just two elements: silver (Ag) and gold (Au). To date, this process is yet to be observed with any other metals. Here, we report the plasmon-driven synthesis of copper (Cu) nanoparticles in aqueous solution via a seed-mediated growth strategy. The plasmonic synthesis is amenable to various Cu precursors, but is highly sensitive to the type of hole scavenger used in the reaction. We also found that the exclusion of oxygen from the system, both in the initial synthesis of Cu seeds and in their subsequent growth into larger nanoparticles, was essential for enabling the plasmon-driven process to proceed. A series of control experiments, supported by photoelectrochemical measurements, were performed to confirm that the growth of Cu nanoparticles occurs via plasmon excitation of the Cu seeds. Overall, our approach offers a unique route to the synthesis of Cu nanoparticles and expands the domain of plasmon-driven photochemistry to a new element.