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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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Interface-Confined Triplet Sensitization and Photon Upconversion in Pyrene-Tetracyanobenzene Charge-Transfer
Jianlei Han1, Zhiying Bai2, Jiao Mu2
1College of Biological and Chemical Engineering, Jiaxing University, Jiaxing 314001, China.
Journal of the American Chemical Society
|November 20, 2025
Summary
Researchers developed efficient, heavy-atom-free photon upconversion systems using charge-transfer (CT) excitons. These systems utilize micro-cocrystals to sensitize triplet acceptors, enabling highly efficient triplet-triplet annihilation photon upconversion (TTA-UC).
Area of Science:
- Materials Science
- Photochemistry
- Organic Electronics
Background:
- Intermolecular charge-transfer (CT) complexes exhibit unique photophysical properties.
- Photon upconversion (UC) processes are crucial for various photonic applications.
- Triplet-triplet annihilation photon upconversion (TTA-UC) typically requires heavy atoms for efficient intersystem crossing.
Purpose of the Study:
- To demonstrate the use of CT excitons as triplet sensitizers in TTA-UC.
- To achieve efficient heavy-atom-free photon upconversion.
- To explore novel materials for advanced photonic devices.
Main Methods:
- Fabrication of pyrene-tetracyanobenzene CT complex micro-cocrystals via a solution-based method.
- Observation of intersystem crossing of CT excitons to form triplet excitons.
- Demonstration of triplet-triplet energy transfer from CT triplet excitons to diphenylanthracene (DPA) acceptors.
Main Results:
- Efficient triplet sensitization by CT excitons was achieved.
- Highly efficient TTA-UC was demonstrated, converting 532 nm to 430 nm.
- The system proved to be heavy-atom-free, overcoming a common limitation in UC.
Conclusions:
- CT excitons in micro-cocrystals can serve as effective triplet sensitizers for TTA-UC.
- This work presents a novel and efficient heavy-atom-free approach for photon upconversion.
- The findings open new avenues for designing advanced UC materials and systems.
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