Fabrication of Large-Area Fully Alloyed Ag/Au Nanoparticle Arrays

The potential applications of nanoparticles in future technologies are extensive. Many of those applications require assembly of monodispersed nanostructures into ordered macroscopic building blocks, such as arrays, to enable their integration into complex devices. Examples of such applications include electrical contacts to nanoparticles in electro-optical devices and nanogap-enabled chemical sensors. Herein, we present a versatile approach to fabricate extended and highly ordered arrays of fully alloyed Ag/Au nanoparticles on solid substrates that can be easily expanded to other binary and even higher alloys. The strategy is demonstrated by fabricating Ag/Au alloys with Ag compositions ranging from 0% to 100%. As expected, the plasmon resonance of the alloyed nanoparticles could be varied between those of pristine Au and Ag. The width of the plasmon resonance was significantly smaller compared to those of partially low-temperature alloyed mixtures presented previously. Finally, a Cu 2 O semiconductor shell was grown on the alloy core to demonstrate that the resulting nanoparticle surfaces are accessible for functionalization, therefore broadening the potential applications of the material.