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Updated: May 2, 2026
11:26
Integrating a Triplet-triplet Annihilation Up-conversion System to Enhance Dye-sensitized Solar Cell Response to Sub-bandgap Light
Published on: September 12, 2014
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Unimolecular Doublet-Triplet Annihilation Upconversion in Iron(III) Coordination Compounds
Florian Doettinger1, Oliver S Wenger1
1Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland.
Journal of the American Chemical Society
|April 30, 2026
Summary
Researchers report a new type of molecular upconversion using single molecules. This novel doublet-triplet annihilation process avoids diffusion and reduces energy loss, offering advantages over traditional methods.
Area of Science:
- Photochemistry
- Molecular Engineering
- Materials Science
Background:
- Conventional photochemical upconversion relies on intermolecular energy transfer and triplet-triplet annihilation.
- These processes are diffusion-dependent and can involve significant energy losses.
Purpose of the Study:
- To report a novel unimolecular upconversion mechanism.
- To explore upconversion via doublet-triplet annihilation in single molecules.
- To design and characterize molecules for diffusion-independent upconversion.
Main Methods:
- Design and synthesis of molecules integrating an Fe(III) carbene complex and perylene units.
- Spectroscopic characterization of excited states (doublet, triplet, singlet).
- Investigation of upconversion efficiency by varying the number of perylene units (1-4).
- Testing upconversion in fluid solution, polymers, and frozen glasses.
Main Results:
- Demonstrated unimolecular upconversion via doublet-triplet annihilation, bypassing conventional principles.
- Achieved diffusion-independent upconversion with reduced energy losses.
- Identified optimal molecular design for efficient unimolecular upconversion.
- Confirmed functionality across different states (solution, polymer, frozen glass).
Conclusions:
- Unimolecular doublet-triplet annihilation is a fundamentally new upconversion concept.
- This approach offers strategic advantages over conventional triplet-triplet annihilation.
- Provides a design strategy for future diffusion-independent upconversion architectures.
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