Dr Christian A. Nijhuis, Department of Chemistry, National University of Singapore.
Playing with Light at the Molecular Length-scale: Molecular Electronic Plasmon Sources.
To realize nano-scale opto-electronic circuitry, one needs to be able to excite and detect surface plasmon polaritons by electrical means. Tunnel junctions can excite and detect plasmons in a single step without the need for external light sources and optical elements [1-3]. In these devices, currents are directly converted to plasmons in a single step, and vice versa, and tunnel junctions are widely used in commercial devices. During this talk, recent progress in the development of molecular tunnel junctions  and how they are applied as electrical excitation sources [5-8] will be discussed. By simply applying a bias between the top and bottom electrode, a tunnelling current will flow across the molecules which excites surface plasmon polaritons in the plasmonic electrode materials. Since the tunnelling rate and direction can be controlled by simply changing the chemical structure of the molecules, it is possible to control the plasmonic properties of the devices and launch plasmons (and the polarization of the emitted photons) . These plasmon sources behave as point sources whose blinking properties and photon energies can be controlled by simply changing the molecular structure giving new insights in the mechanism of charge transport . Finally, by integrating two tunnel junctions with one plasmonic wave-guide, it can be demonstrated that the tunnel junctions are also promising as plasmon detectors with plasmon-electron coupling efficiencies of more than 1000 times higher than previous estimates based on photon out coupling rates . Results show that molecular electronics make it possible to manipulate light at the nano-scale and are interesting for applications in plasmonic-electronics in general.
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ABOUT THE PRESENTER
Christian A. Nijhuis received his Master’s degree in Chemistry from the University of Groningen in 2002, and Ph.D. degree from University of Twente in 2006 (Cum Laude; top 5%). Under the direction of Professor David N. Reinhoudt, his doctoral thesis included studies on the surface chemistry of supramolecular assemblies and their use in bottom-up nano-fabrication. He received the Simon Stevin Research award from the Netherlands Organization for Scientific Research (NWO) in 2006 to conduct overseas research. In the group of Professor George M. Whitesides, as a postdoctoral research fellow, he developed a platform for measurements of charge transport across layers that are one molecule thick. In 2010, he received the NRF (National Research Foundation of Singapore) research fellowship and he joined the Department of Chemistry at the National University of Singapore. In 2012, he received the NRF CRP grant to start a new program to develop plasmonic-electronic devices which was continued in 2017 (project value 9 million SGD). He currently uses bottom-up nanofabrication techniques to construct self-assembled nano-electronic devices to study light matter interactions and charge transport across molecular junctions. Other interests include synchrotron based surface characterization, self-assembly, synthesis, 2D materials, and nanoscale dynamics.
Tea/coffee will be available at 13h45
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