Synthesis and Exciton Dynamics of Donor-Orthogonal Acceptor Conjugated Polymers: Reducing the Singlet-Triplet Energy Gap
| Autor: | Alexander K. Forster, Alexandros G. Rapidis, Andrew J. Musser, Franco Cacialli, Hugo Bronstein, Richard H. Friend, David M.E. Freeman, Hannah L. Stern, Jarvist M. Frost, Kealan J. Fallon, Iain McCulloch, Tracey M. Clarke |
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| Přispěvatelé: | Fallon, Kealan [0000-0001-6241-6034], Friend, Richard [0000-0001-6565-6308], Bronstein, Hugo [0000-0003-0293-8775], Apollo - University of Cambridge Repository |
| Rok vydání: | 2017 |
| Předmět: |
Band gap
Exciton Population 02 engineering and technology Conjugated system 010402 general chemistry 7. Clean energy 01 natural sciences Biochemistry Catalysis Colloid and Surface Chemistry Singlet state education education.field_of_study business.industry Chemistry Exchange interaction General Chemistry 0303 Macromolecular and Materials Chemistry 021001 nanoscience & nanotechnology Acceptor 0104 chemical sciences Organic semiconductor Chemical physics Optoelectronics 0210 nano-technology business |
| Zdroj: | Journal of the American Chemical Society |
| ISSN: | 1520-5126 |
| Popis: | The presence of energetically low-lying triplet states is a hallmark of organic semiconductors. Even though they present a wealth of interesting photophysical properties, these optically dark states significantly limit optoelectronic device performance. Recent advances in emissive charge-transfer molecules have pioneered routes to reduce the energy gap between triplets and "bright" singlets, allowing thermal population exchange between them and eliminating a significant loss channel in devices. In conjugated polymers, this gap has proved resistant to modification. Here, we introduce a general approach to reduce the singlet-triplet energy gap in fully conjugated polymers, using a donor-orthogonal acceptor motif to spatially separate electron and hole wave functions. This new generation of conjugated polymers allows for a greatly reduced exchange energy, enhancing triplet formation and enabling thermally activated delayed fluorescence. We find that the mechanisms of both processes are driven by excited-state mixing between π-π*and charge-transfer states, affording new insight into reverse intersystem crossing. |
| Databáze: | OpenAIRE |
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