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.