Efficient Multiexciton State Generation in Charge-Transfer-Coupled Perylene Bisimide Dimers via Structural Control
| Autor: | Dongho Kim, Woojae Kim, Yongseok Hong, Hyungjun Kim, Frank Würthner, Juno Kim, Christina Kaufmann |
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| Rok vydání: | 2020 |
| Předmět: |
Coupling
Field (physics) Exciton Relaxation (NMR) Charge (physics) General Chemistry 010402 general chemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences chemistry.chemical_compound Colloid and Surface Chemistry Thermalisation chemistry Chemical physics Singlet fission Perylene |
| Zdroj: | Journal of the American Chemical Society. 142(17) |
| ISSN: | 1520-5126 |
| Popis: | The singlet fission (SF) process is generally defined as the conversion of one singlet exciton (S1) into two triplet excitons (2·T1), which has the potential to overcome thermalization losses in the field of photovoltaic devices. Among the applicable compounds for SF-based photovoltaic devices, perylene bisimide (PBI) is one of the best candidates because of its electronic tunability and photostability. However, the strategy for efficient SF in PBIs remains ambiguous because of numerous competing relaxation pathways in PBI-based molecular materials. In this regard, for the first time, we observed the SF mechanism in PBI dimers by controlling the intrinsic factor (exciton coupling) and the external environment (solvent polarity and viscosity). Time-resolved spectroscopic measurements and quantum chemical simulations reveal that efficient SF occurs through the charge-transfer-assisted mechanism, entailing a large structural fluctuation. Our findings not only highlight the SF mechanism in PBI dimers but also suggest the factors responsible for an efficient SF process, which are important considerations in the design of molecular materials for photovoltaic devices. |
| Databáze: | OpenAIRE |
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