The fabrication of highly ordered silver nanodot patterns by platinum assisted nanoimprint lithography

Silver has been widely used for optical sensing and imaging applications which benefit from localized surface plasmon resonance (LSPR) in a nanoscale configuration. Many attempts have been made to fabricate and control silver nanostructures in order to improve the high performance in sensing and other applications. However, a fatal mechanical weakness of silver and a lack of durability in oxygen-rich conditions have disrupted the manufacturing of reproducible nanostructures by the top-down lithography approach. In this study, we suggest a steady fabrication strategy to obtain highly ordered silver nanopatterns that are able to provide tunable LSPR characteristics. By using a protecting layer of platinum on a silver surface in the lithography process, we successfully obtained large-area (2.7 × 2.7 mm(2)) silver nanopatterns with high reproducibility. This large-area silver nanopattern was capable of enhancing the low concentration of a Cy3 fluorescence signal (∼10(-10) M) which was labeled with DNA oligomers.