Browsing by Author "Dionne, Jennifer A."

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    Mechanism for plasmon-generated solvated electrons
    (PNAS, 2023) Al-Zubeidi, Alexander; Ostovar, Behnaz; Carlin, Claire C.; Li, Boxi Cam; Lee, Stephen A.; Chiang, Wei-Yi; Gross, Niklas; Dutta, Sukanya; Misiura, Anastasiia; Searles, Emily K.; Chakraborty, Amrita; Roberts, Sean T.; Dionne, Jennifer A.; Rossky, Peter J.; Landes, Christy F.; Link, Stephan; Center for Adapting Flaws into Features
    Solvated electrons are powerful reducing agents capable of driving some of the most energetically expensive reduction reactions. Their generation under mild and sustainable conditions remains challenging though. Using near-ultraviolet irradiation under low-intensity one-photon conditions coupled with electrochemical and optical detection, we show that the yield of solvated electrons in water is increased more than 10 times for nanoparticle-decorated electrodes compared to smooth silver electrodes. Based on the simulations of electric fields and hot carrier distributions, we determine that hot electrons generated by plasmons are injected into water to form solvated electrons. Both yield enhancement and hot carrier production spectrally follow the plasmonic near-field. The ability to enhance solvated electron yields in a controlled manner by tailoring nanoparticle plasmons opens up a promising strategy for exploiting solvated electrons in chemical reactions.
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    Temperature-dependent optical properties of titanium nitride
    (AIP Publishing LLC, 2017) Briggs, Justin A.; Naik, Gururaj V.; Zhao, Yang; Petach, Trevor A.; Sahasrabuddhe, Kunal; Goldhaber-Gordon, David; Melosh, Nicholas A.; Dionne, Jennifer A.
    The refractory metal titanium nitride is promising for high-temperature nanophotonic and plasmonic applications, but its optical properties have not been studied at temperatures exceeding 400 °C. Here, we perform in-situ high-temperature ellipsometry to quantify the permittivity of TiN films from room temperature to 1258 °C. We find that the material becomes more absorptive at higher temperatures but maintains its metallic character throughout visible and near infrared frequencies. X-ray diffraction, atomic force microscopy, and mass spectrometry confirm that TiN retains its bulk crystal quality and that thermal cycling increases the surface roughness, reduces the lattice constant, and reduces the carbon and oxygen contaminant concentrations. The changes in the optical properties of the material are highly reproducible upon repeated heating and cooling, and the room-temperature properties are fully recoverable after cooling. Using the measured high-temperature permittivity, we compute the emissivity, surface plasmon polariton propagation length, and two localized surface plasmon resonance figures of merit as functions of temperature. Our results indicate that titanium nitride is a viable plasmonic material throughout the full temperature range explored.