A microfluidic device for high-throughput synthesis of silver and gold nanostructures will be developed. We will design and fabricate microsystems that can simultaneously perform hundreds of reaction conditions on one chip with extreme precision and control. This will greatly improve the tunability of each reaction condition allowing for us to tailor the reaction conditions to synthesize nanostructures with controllable plasmon shifts. Hollow metal particles will be prepared based on a galvanic replacement reaction, which is a method driven by the electrical potential difference between two metals, with one metal acting as the cathode and the other metal as the anode. Initially, Ag nanostructures act as sacrificial templates on which Au atoms are able to epitaxially nucleate on. Through a series of alloying/dealloying steps the process results in the formation of Au-base hollow nanostructures, with structures predetermined by the initial Ag template. By introducing precise and discrete concentrations of the cathodic metal (AuCl4-) the extent of the template hollowing, and thus the plasmon shift can be well controlled.
Project end date: 08/10/09