Conducting polymer–gold co-patterned surfaces via nanosphere lithography

Abstract

HypothesisCo-patterned arrays comprised of conjugated polymers and nanostructured gold is an important matrix for sensing and stimuli-responsive plasmonic applications. Nanosphere lithography (NSL) is an easy-to-use patterning technique and viable method to fabricate inverse honeycomb structures with electrochemically deposited conjugated polymers. The cross-sectional height of the conducting polymer pattern can be tuned such that the macropores of the honeycomb structure expose electrochemically accessible areas for further gold deposition. Using time-dependent electrochemical reduction, Au3+ is reduced to Au0 and selectively deposit on the macropores thus forming a co-patterned surface. ExperimentsThe Langmuir–Blodgett-like deposition was used to assemble polystyrene spheres on a conductive substrate. Then the carbazole-based monomer was electropolymerized within the interstices of the colloidal template, which was subsequently dissolved. A potentiostatic technique was used to deposit Au in the macropores. FindingsFabrication of the polycarbazole–Au co-patterned surface was characterized by atomic force microscopy (AFM), electrochemical quartz crystal microbalance (EC-QCM), and X-ray photoelectron spectroscopy (XPS). Surface plasmon resonance spectroscopy (SPS) data supported backfilling behavior and quantified the complex refractive index of the array. UV–Vis absorption spectroscopy shows overlapping polycarbazole and gold LSPR peaks useful for plasmonic sensing applications. The colloidal templating approach reported in this study was further used in the fabrication of highly ordered Au nanodisks.