Phonon-assisted molecular upconversion in a holmium(III)-based molecular cluster-aggregate

Diogo A Gálico; Rayan Ramdani; Muralee Murugesu

doi:10.1039/d2nr02643k

Phonon-assisted molecular upconversion in a holmium(III)-based molecular cluster-aggregate

Nanoscale. 2022 Jul 14;14(27):9675-9680. doi: 10.1039/d2nr02643k.

Authors

Diogo A Gálico¹, Rayan Ramdani¹, Muralee Murugesu¹

Affiliation

¹ Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada. m.murugesu@uottawa.ca.

PMID: 35775625
DOI: 10.1039/d2nr02643k

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 Ho^III ion molecular upconversion. The synthesized MCA exhibits identifiable Ho^III 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%.