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Updated: Jul 5, 2026

Triplet Fusion Upconversion Nanocapsule Synthesis
Published on: September 7, 2022
Open- and Closed-Shell Roles of Sensitizer and Annihilator in Pseudo-Single Component Mixtures for Upconversion
Kieran D Richards1,2, Wenzhao Wang3, Philipp Thielert4
1Department of Chemistry, Swansea University, Singleton Park, Swansea SA2 8PP, United Kingdom.
Researchers developed a novel photon upconversion method using organic radicals as sensitizers and their hydrogenated forms as annihilators. This approach overcomes energy loss limitations, enabling efficient red-to-blue light conversion for advanced optoelectronics.
Area of Science:
- Materials Science
- Photochemistry
- Organic Electronics
Background:
- Photon upconversion is crucial for optoelectronics, but traditional methods using closed-shell sensitizers suffer energy losses.
- Singlet-triplet intersystem crossing limits efficiency in conventional upconversion systems.
Purpose of the Study:
- To explore open-shell organic radicals and their closed-shell hydrogenated analogues for efficient photon upconversion.
- To investigate a novel upconversion mechanism involving intermolecular energy transfer between sensitizers and annihilators.
Main Methods:
- Synthesized a molecule (TTM-1Cz-DPA) combining a triphenylmethyl radical sensitizer with an anthracene-based component.
- Utilized its closed-shell hydrogenated analogue (HTTM-1Cz-DPA) as an annihilator.
- Demonstrated red-to-blue photon upconversion in solution via intermolecular energy transfer.
Main Results:
- Achieved apparent anti-Stokes shift greater than 0.9 eV.
- Obtained a 7% quantum efficiency for red-to-blue photon upconversion.
- Confirmed the essential role of the hydrogenated precursor with radicals for high performance.
Conclusions:
- Open-shell organic radicals and closed-shell hydrogenated analogues offer a new pathway for efficient photon upconversion.
- This paired system overcomes limitations of traditional sensitizers, enabling enhanced energy management.
- Understanding emergent spin-optical properties in these systems opens opportunities in photonics and optoelectronics.
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