Harnessing Surface Plasmon Subwavelength Optics in Metallic Nanostructures for Enhanced Efficiency in Thin-Film Solar Cells Sang-Hyun Oh, Department of Electrical and Computer Engineering University of Minnesota, Twin Cities Plasmonics is a rapidly emerging field of using metallic nanostructures, which exhibit “plasmon” oscillations of the free electrons, for the sub-wavelength control and confinement of optical energy. In this work, a colloidal self-assembly technique known as nanosphere lithography is employed to pattern periodic nanohole arrays with tunable spacing, size and shape in thin silver films, which act as semi-transparent plasmonic electrodes. Incident light is converted into surface plasmons that can confine optical energy within a volume well below the diffraction limit and enhance light-matter interactions in thin-film organic photovoltaic cells (OPV). By harnessing these, we were able to demonstrate a plasmonic OPV with a performance that matches OPVs constructed on a conventional indium tin oxide (ITO) electrode.