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Triplet-Triplet Annihilation Upconversion: From Molecules to Materials.
Hong-Juan Feng1, Ming-Yu Zhang1, Lin-Han Jiang1
1Tianjin Key Laboratory of Biosensing and Molecular Recognition, Research Center for Analytical Sciences, Frontiers Science Center for New Organic Matter, Haihe Laboratory of Sustainable Chemical Transformations, Academy for Advanced Interdisciplinary Studies, College of Chemistry, Nankai University, Tianjin 300071, P. R. China.
Accounts of Chemical Research
|September 17, 2025
Summary
Triplet-triplet annihilation upconversion (TTA-UC) converts low-energy photons to high-energy ones. This study details breakthroughs in TTA-UC materials for enhanced biosensing, catalysis, and energy applications.
Area of Science:
- Organic photonics and materials science.
- Photophysical processes and molecular engineering.
- Nanotechnology and supramolecular chemistry.
Background:
- Photon upconversion, especially triplet-triplet annihilation upconversion (TTA-UC), offers unique properties for diverse applications by converting low-energy photons to higher-energy ones.
- TTA-UC materials show promise in biosensing, biomedicine, photoredox catalysis, and solar energy harvesting, but challenges remain in developing high-performance near-infrared (NIR) emitters, water-dispersible nanoparticles, and clinical translation.
- Existing TTA-UC systems face limitations in anti-Stokes shift, stability, and efficiency, hindering broader application.
Purpose of the Study:
- To systematically introduce laboratory breakthroughs in triplet-triplet annihilation upconversion (TTA-UC) materials and their applications.
- To address challenges in TTA-UC performance, stability, and dispersibility for advanced applications.
- To explore novel molecular designs and material strategies for enhanced TTA-UC efficiency and broader utility.
Main Methods:
- Synthesis of a B,N-doped NIR-absorbing photosensitizer with thermally activated delayed fluorescence.
- Construction of TTA-UC systems utilizing novel ligands (thiophene-substituted diketopyrrolopyrrole) on lead sulfide quantum dots (PbS QDs).
- Development of soft core-shell nanostructures and porous aromatic framework (PAF)-based TTA-UC materials.
- Fabrication of biocompatible photonic upconversion supramolecular assemblies using proteins.
- Investigation of TTA-UC for biosensing, oxygen sensing, and photocatalysis.
Main Results:
- Achieved TTA-UC with an anti-Stokes shift up to 1.03 eV (NIR to blue light) using a novel photosensitizer.
- Demonstrated efficient triplet exciton transfer (up to 90%) on PbS QDs with a novel ligand, enabling TTA-UC with 1064 nm excitation and near-theoretical anti-Stokes shift.
- Developed water-dispersible TTA-UC nanoparticles via a soft core-shell strategy and high-performance PAF-based TTA-UC materials.
- Fabricated biocompatible TTA-UC supramolecular assemblies for sensitive prostate tumor marker detection.
- Showcased PAF-based TTA-UC for wide-range oxygen sensing and as efficient heterogeneous photocatalysts for photoredox reactions.
Conclusions:
- Significant advancements in TTA-UC materials have been achieved through rational molecular design and novel material strategies.
- The developed TTA-UC systems demonstrate high performance, stability, and versatility for applications in biosensing, energy, and catalysis.
- Continued exploration of TTA-UC from molecular to material scales promises substantial progress and practical implementation in various scientific fields.
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