Nanoimprint Lithography and its Applications in Photonics, Biotechnology and Energy Conversion Devices

Abstract

Large-area, uniformly oriented plasmonic arrays were fabricated using nanoimprint lithography (NIL). Excellent control of the Localized Surface Plasmon Resonance of the metallic arrays is demonstrated through nanoparticle material composition, size characteristics and polarization effects. Additionally, the dichroic properties were further explored using spectroscopic ellipsometry.

The plasmonic features of random and highly ordered gold nanostructure arrays (NSA) prepared by thermally annealed island film and NIL were compared. Both fabrication methods allow spectral tuning of plasmon resonance position depending on size and shape of nanostructures; however, the time and cost is quite different. The respective comparison was performed experimentally and theoretically for a number of samples with different geometrical parameters.

NIL-produced plasmonic arrays were utilized to detect the biomolecular interaction between bovine serum albumin and its specific antibody. The recording of a real-time assay using different antibody concentrations demonstrated the ability of the plasmonic arrays to transduce binding. Moreover, the sample was demonstrated to be robust, reproducible and reusable.

In order to demonstrate relevance of NIL to energy conversion devices, NIL was used to fabricate electrodes with high specific Pt surface areas for use in micro-fuel cell devices. The Pt catalyst structures were characterized electrochemically using cyclic voltammetry and were tested in fuel cell membrane electrode assemblies (MEA) by directly embossing a Nafion 117 membrane. The features of the mold were successfully transferred to the Nafion and a 7.5 nm thin film of Pt was deposited to form the anode catalyst layer. The resulting MEA yielded a very high Pt utilization of 15,375 mW mg-1 Pt compared to conventionally prepared MEAs (820 mW mg-1 Pt). Embossing pattern transfer was also demonstrated for spin casted Nafion films which could be used for new applications.