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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
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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.
Nanoscale
|July 1, 2022
Summary
Researchers achieved molecular upconversion (UC) using lanthanide ions, specifically Holmium (HoIII), in a novel molecular cluster-aggregate. This breakthrough enables efficient light emission at the molecular scale, paving the way for new optical materials.
Area of Science:
- Materials Science
- Photochemistry
- Nanotechnology
Background:
- Upconversion (UC) involves emitting higher energy photons upon excitation by lower energy photons.
- Achieving efficient UC at the molecular scale using lanthanide ions presents a significant challenge.
- Downscaling UC processes is crucial for advanced optical applications.
Purpose of the Study:
- To demonstrate molecular upconversion (UC) using Holmium (HoIII) ions.
- To design and synthesize a molecular cluster-aggregate (MCA) for enhanced UC.
- To investigate the mechanisms behind enhanced UC emission.
Main Methods:
- Rational design and synthesis of a molecular cluster-aggregate (MCA).
- Characterization of the MCA for UC properties.
- Analysis of emission spectra, including green, red, and near-infrared (NIR) UC emissions.
- Investigation of phonon-assisted energy transfer mechanisms.
Main Results:
- Successful demonstration of HoIII ion molecular upconversion for the first time.
- The synthesized MCA exhibited distinct green and red UC emissions with an enhanced red-to-green ratio.
- A conventional near-infrared (NIR) emission was also observed.
- Achieved an upconversion quantum yield of 5.24 × 10⁻⁶%.
Conclusions:
- The developed MCA enables efficient molecular upconversion with HoIII ions.
- A rigid cluster core and matched energy levels via phonon-assisted mechanisms are key to enhanced UC.
- This work advances the field of molecular photonics and nanoscale optical materials.
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