Icon for: Jesse Kohl

JESSE KOHL

Rutgers University
Years in Grad School: 4
Public
Choice

Judges’ Queries and Presenter’s Replies

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Presentation Discussion
  • May 21, 2012 | 11:32 p.m.

    nice presentation and poster.

    I guess the only question I have is related to your poster. Specifically, it was unclear to me what was the goal you were trying to achieve with the experimental results you generated. I must admit that this is not my field, but your poster was very interesting.

  • Icon for: Jesse Kohl

    Jesse Kohl

    Presenter
    May 22, 2012 | 10:49 a.m.

    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

  • Icon for: Robert Opila

    Robert Opila

    Faculty
    May 25, 2012 | 06:31 a.m.

    Jesse—good job—I believe that light harvesting is “low hanging fruit” for the PV industry. We throw lots of photons away. This kind of work is a good start for looking at real alternatives. Any plans for incorporation of any of these ideas into devices?

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    Jesse Kohl

    Presenter
    May 25, 2012 | 09:49 a.m.

    Hello Prof. Opila,

    Much thanks for your interest. As I am learning more about plasmonics and metal-semiconductor interfaces, I agree that there is a significant room for loss mitigation at the interface. We are working to directly utilize nanoantennas and other types of plasmonic electrodes in both conventional and inverted organic photovoltaic cells. We are specifically looking to engineer the surface plasmon mode profiles and control of the surface work-function of the metal so that the metal electrode performs as a selective contact for one of the charge carriers. Ultimately, it will require a high degree of control of the metal-semiconductor interface by ultra-thin interfacial layers and further elucidating the opto-electronic interactions between the semiconductor and plasmonic nanostructure. Hopefully more to come in the near future!

    Best regards,

    Jesse Kohl

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