The convergence of nanooptics and surface chemistry

December 8, 2017

Dr. Terefe Habteyes, UNM

Research progress in nanooptics and nanophotonics over the past several decades shows that nanoscale materials increase light-matter interaction dramatically and provide optical tunability simply by changing the dimension of the same material composition. These optical characteristics are desirable for harvesting energy of the broad solar spectrum, highly sensitive microscopy, spectroscopy, photodetection, photocatalysis, and many other optoelectronic applications. Our research utilizes nanoscale optical properties to overcome the fundamental resolution limit imposed by the diffraction property of light and achieve super-resolution near-field imaging, to investigate interface properties and interparticle interactions, and to drive and probe surface chemistry with highly sensitive in situ vibrational spectroscopy. In this presentation, representative results that illustrate each of these research activities will be discussed with particular emphasis on recent not yet published results. Plasmon-driven photochemical reactions will be discussed based on our recent exciting experimental observations, where the remarkable effects of surface ligands as well as simultaneous excitation of particle and molecular resonances are demonstrated. The results provide important insight into the mechanism of plasmon-driven surface photochemistry, and at the same time, indicate the hidden chemistry on metal surfaces, where looking at molecules based on their fluorescence is no longer a possibility. Plasmon enhanced exciton generation and temperature dependent emission enhancement will be discussed based on results obtained on epitaxial quantum dots and quantum well near-infrared emitters. Plasmonic interactions at touching or subnanometer coupling limit that leads to quantum mechanical phenomena will be highlighted as current and future research directions.