- School of Physics - Research Publications
School of Physics - Research Publications
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ItemHot-Carrier Organic Synthesis via the Near-Perfect Absorption of LightXiao, Q ; Connell, TU ; Cadusch, JJ ; Roberts, A ; Chesman, ASR ; Gomez, DE (AMER CHEMICAL SOC, 2018-11-01)Photocatalysis enables the synthesis of valuable organic compounds by exploiting photons as a chemical reagent. Although light absorption is an intrinsic step, existing approaches rely on poorly absorbing catalysts that require high illumination intensities to afford enhanced efficiencies. Here, we demonstrate that a plasmonic metamaterial capable of near-perfect light absorption (94%) readily catalyzes a model organic reaction with a 29-fold enhancement in conversion relative to controls. The oxidation of benzylamine proceeds via a reactive iminium intermediate with high selectivity at ambient temperature and pressure, using only low-intensity visible irradiation. Control experiments demonstrated that only hot charge carriers produced following photoexcitation facilitate the formation of superoxide radicals, which, in turn, leads to iminium formation. Modeling shows that hot holes with energies that overlap with the highest-occupied molecular orbital (HOMO) of the reactant can participate and initiate the photocatalytic conversion. These results have important implications for hot-carrier photocatalysis and plasmon-hot-carrier extraction.
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ItemIn-Plane Detection of Guided Surface Plasmons for High-Speed Optoelectronic Integrated CircuitsPanchenko, E ; Cadusch, JJ ; Avayu, O ; Ellenbogen, T ; James, TD ; Gomez, D ; Roberts, A (WILEY, 2018-01)Abstract Constrains on the speed of modern digital integrated circuits are dominated by the metallic interconnects between logic gates. Surface plasmon polaritons have potential to overcome this limitation and greatly increase the operating speed of future digital devices. Nevertheless, an ongoing issue is the compatibility of modern planar microelectronic circuits with current methods for detecting surface plasmons. Here, a new approach to in‐plane surface plasmon polariton detection is proposed and experimentally demonstrated. The design is based on metal–semiconductor–metal photodetectors that are acknowledged as having one of the best speed characteristics among photodetectors. In the design, the photodetector structure also plays a dual role as the outcoupling grating for surface plasmons, significantly reducing the footprint of the resulting device. The technique has the potential to enable the integration of surface plasmons as signal carriers in future high‐speed optoelectronic integrated circuits.