Ordered Arrays of Nanoporous Gold Nanoparticles
A combination of a “top-down” approach (substrate conformal imprint lithography) and two “bottom-up” approaches (dewetting and dealloying) enables fabrication of perfectly ordered 2-dimensional arrays of nanoporous gold nano particles. The dewetting of Au/Ag bi-layers on the periodically pre-patterned substrates leads to the formation of an array of Au-Ag alloy nanoparticles. The array of alloy nanoparticles is transformed into an array of nanoporous gold nanoparticles by a following dealloying step. Large areas of this new type of material arrangement can be realized with this technique. In addition, this technique allows for the control of particle size, particle spacing, and ligament size (or pore size) by varying the period of the structure, total metal layer thickness, and the thickness ratio of the as-deposited bi-layers.