Hello Prof. Shin,

I consider the body of work presented in the poster as a fundamental study of how to manipulate and confine light on the nanoscale for opto-electronic devices through the interplay between metallic nanostructures and conjugated organic semiconducting polymers. From an applications standpoint, we are interested integrating plasmon-polymer interactions in: (i) thin film organic photovoltaics to increase light trapping and harvesting efficiency, (ii) organic light emitting diodes (specifically blue OLEDs) to increase light out-coupling efficiency, and (iii) in the development of nanophotonic components such as coherent plasmonic lasers and interconnects for opto-electronic circuitry.

The gold nanotubes presented in the poster are of interest as both out-coupling structures for organic light-emitting diodes and potentially as a nanoscale resonator cavity for a plasmonic laser. In such a applications, the nanotube(s) would be cladded or in-filled with a light emitting polymer, allowing for the propagating plasmon mode to couple with the polymer emitter. To successfully achieve this goal, we needed a clear understanding of the resonant modes and the ‘plasmonic’ behavior of these tubes to optimize its interaction with the polymer emitter. The study presented in the poster explores the types of plasmon modes supported by tubular metallic nanostructures and how the mode propagation length varies with geometry (wall thickness) and excitation polarization. This knowledge will in turn allow tunability of the structures to be match the peak emission wavelength of an emitting polymer and help in maximizing plasmon-emitter coupling.

With regards to the nano-antennas, theoretical studies have proposed linear metal–semiconductor–metal nanoantennas where semiconductor material is incorporated into a central ‘slot region’ of a noble metal nanorod, in analogy to the feed element in radio frequency antennas. This not only allows the full benefit of local-field effects in the antenna near-field to be exploited, but also permits light to be efficiently in/out coupled to sub-wavelength volumes. We study how these structures can modify and enhance the absorption and emission rate in organic semiconductor materials and how molecular ordering improves nanoscale organic photonic device performance. In particular, organic conjugated polymer semiconductors such as polythiophene, which exhibit high carrier mobilities but possess relatively poor luminescence properties would benefit from plasmonic nanoantennas, potentially opening up opportunities for use as the active material in organic light-emitting optoelectronic devices. Applications where semiconductor radiative emission rate is the critical parameter include optical communications or modulation.

Thank you for your interest,

Jesse Kohl