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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Phonon-assisted molecular upconversion in a holmium(III)-based molecular cluster-aggregate
Diogo A Gálico1, Rayan Ramdani1, Muralee Murugesu1
1Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. m.murugesu@uottawa.ca.
Abstract:
Upconversion (UC) is a fascinating process in which higher energy photons can be emitted from excitation by lower energy photons. The current challenge remains in downscaling and effectively achieving upconversion with lanthanide ions at the molecular scale. Here, using a rationally designed molecular cluster-aggregate (MCA), we demonstrate for the first time HoIII ion molecular upconversion. The synthesized MCA exhibits identifiable HoIII green and red UC emissions with a uniquely enhanced red to green ratio as well as a conventional near-infrared (NIR) emission. A combined rigid spherical cluster core with reduced molecular vibrations, ideally matched donor and acceptor excited levels via a phonon-assisted mechanism, led to an upconversion quantum yield of 5.24 × 10-6%.
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