High Exciton Diffusion Coefficients in Fused Ring Electron Acceptor Films
| Autor: | Shyamal K. K. Prasad, Xiaowei Zhan, Sreelakshmi Chandrabose, Alex J. Barker, Kai Chen, Jingshuai Zhu, Joshua J. Sutton, Justin M. Hodgkiss, Jiadong Zhou, Zengqi Xie, Keith C. Gordon |
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| Rok vydání: | 2019 |
| Předmět: |
chemistry.chemical_classification
Fullerene Exciton Transition dipole moment Heterojunction General Chemistry Electron acceptor Chromophore Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 010402 general chemistry 01 natural sciences Biochemistry Catalysis 0104 chemical sciences Organic semiconductor Condensed Matter::Materials Science Colloid and Surface Chemistry chemistry Chemical physics Diffusion (business) |
| Zdroj: | Journal of the American Chemical Society. 141(17) |
| ISSN: | 1520-5126 |
| Popis: | Modest exciton diffusion lengths dictate the need for nanostructured bulk heterojunctions in organic photovoltaic (OPV) cells; however, this morphology compromises charge collection. Here, we reveal rapid exciton diffusion in films of a fused-ring electron acceptor that, when blended with a donor, already outperforms fullerene-based OPV cells. Temperature-dependent ultrafast exciton annihilation measurements are used to resolve a quasi-activationless exciton diffusion coefficient of at least 2 × 10–2 cm2/s, substantially exceeding typical organic semiconductors and consistent with the 20–50 nm domain sizes in optimized blends. Enhanced three-dimensional diffusion is shown to arise from molecular and packing factors; the rigid planar molecular structure is associated with low reorganization energy, good transition dipole moment alignment, high chromophore density, and low disorder, all enhancing long-range resonant energy transfer. Relieving exciton diffusion constraints has important implications for OPVs... |
| Databáze: | OpenAIRE |
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