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Covalent Fragment Screening Using the Quantitative Irreversible Tethering Assay
Published on: February 28, 2025
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Singlet fission in core-linked terrylenediimide dimers
Xingang Zhao1, Youn Jue Bae1, Michelle Chen1
1Department of Chemistry and Institute for Sustainability and Energy at Northwestern, Northwestern University, Evanston, Illinois 60208-3113, USA.
The Journal of Chemical Physics
|December 31, 2020
Summary
Researchers studied terrylenediimide (TDI) dimers, finding that linker choice controls electronic coupling. This allows independent triplet formation even within a dimer, impacting charge transfer states.
Area of Science:
- Photochemistry
- Organic Electronics
- Supramolecular Chemistry
Background:
- Terrylenediimide (TDI) derivatives are crucial organic semiconductors.
- Understanding multiexciton dynamics in molecular dimers is key for advanced materials.
- Electronic coupling significantly influences excited-state behavior in conjugated systems.
Purpose of the Study:
- To investigate the impact of linker-mediated electronic coupling on multiexciton dynamics in TDI dimers.
- To explore the formation of correlated triplet pair states and their subsequent evolution.
- To elucidate the relationship between electronic coupling, solvent polarity, and charge transfer states.
Main Methods:
- Synthesis of regioisomeric TDI dimers with 1,3- (mTDI2) and 1,4- (pTDI) phenylene spacers.
- Spectroscopic studies (steady-state and time-resolved) to probe excited-state dynamics.
- Computational modeling to understand electronic coupling and state energies.
Main Results:
- Electronic coupling strength, controlled by the phenylene linker, dictates excited-state behavior.
- Independent triplet state formation observed in TDI dimers, despite initial correlated triplet pairs.
- Correlated triplet pair states observed before charge separation in polar solvents with strong electronic coupling.
Conclusions:
- The choice of linker is critical for tuning electronic coupling and controlling exciton dynamics in TDI dimers.
- Independent triplet formation can occur even when the initial excited state is confined to the dimer.
- Strong electronic coupling promotes the observation of correlated triplet pairs over charge separation, even in polar environments.
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