Direct 3D patterning of Au nanoparticle-based microstructures
Résumé
Fabrication of plasmonic nanopatterns by nanolithography has evolved greatly in recent years because of the extensive interest that such patterns awake and their potential applications. Fabrication of 3D structures, however, remains an experimental challenge that is nowadays starting to earn attention in the scientific community. In this aspect, most attempts approach the subject creating composites of metallic nanoparticles embedded in a polymer matrix, thus fabricating the 3D structure by photopolymerization. Nevertheless, the polymer layer will partially hinder the application of these structures on plasmonics or suface-enhanced Raman spectroscopy. In this work, we present the fi rst purely metallic nanoparticle-based 3D microstructures reported, manufactured by radical-mediated two-photon photoreduction. Formed by lines of randomly shaped Au nanoparticles of 200 nm in average, the structures are highly reproducible and controllable in thickness. As an application example, the prepared 3DAu structures were tested as SERS substrates using trans-1,2-bis-(4-pyridyl)-ethylene (BPE) as a non-resonant probe molecule, obtaining excellent results in matters of enhancement, fast response and reproducibility in intensity, a basic feature for quantitative sensing applications.