Delayed Blue Fluorescence via Upper-Triplet State Crossing from C–C Bonded Donor–Acceptor Charge Transfer Molecules with Azatriangulene Cores
| العنوان: | Delayed Blue Fluorescence via Upper-Triplet State Crossing from C–C Bonded Donor–Acceptor Charge Transfer Molecules with Azatriangulene Cores |
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| المؤلفون: | Nadzeya A. Kukhta, Paloma L. dos Santos, Daniel G. Congrave, Andrei S. Batsanov, Martin R. Bryce, Jonathan S. Ward, Andrew P. Monkman |
| المصدر: | Chemistry of Materials Chemistry of materials, 2019, Vol.31(17), pp.6684-6695 [Peer Reviewed Journal] |
| بيانات النشر: | American Chemical Society, 2019. |
| سنة النشر: | 2019 |
| مصطلحات موضوعية: | chemistry.chemical_classification, Chemistry, General Chemical Engineering, Charge (physics), Electron donor, 02 engineering and technology, General Chemistry, Electron acceptor, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, Fluorescence, Article, 0104 chemical sciences, chemistry.chemical_compound, Materials Chemistry, Molecule, Triplet state, 0210 nano-technology, Donor acceptor |
| الوصف: | We report the synthesis and structural and photophysical characterization of two series of molecules with functionalized azatriangulene electron donor cores and three pendant electron acceptor units. The presented donor and acceptor units are joined by C–C bonds, instead of the usual C–heteroatom bonds often found in thermally activated delayed fluorescence (TADF) emitters. The effects of the donor–acceptor strength and donor–acceptor dihedral angle on the emission properties are assessed. The data establish that the singlet–triplet energy gap is >0.3 eV and that delayed emission is present in only specific host matrices, irrespective of host polarity. Specific host behavior is atypical of many TADF materials, and we suggest the delayed emission in this work does not occur by a conventional vibronically coupled TADF mechanism, as the ΔEST value is too large. Detailed photophysical analysis and supporting density functional theory calculations suggest that some presented azatriangulene molecules emit via an upper-triplet state crossing mechanism. This work highlights that several different mechanisms can be responsible for delayed emission, often with highly similar photophysics. Detailed photophysical analysis is required to establish which delayed emission mechanism is occurring. Our results also highlight a clear future direction toward vibronically coupled C–C bonded TADF materials. |
| وصف الملف: | application/pdf |
| اللغة: | English |
| تدمد: | 1520-5002 0897-4756 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e2ed4e83fbcc3560a77edd9fea4809a9 http://europepmc.org/articles/PMC7011764 |
| حقوق: | OPEN |
| رقم الأكسشن: | edsair.doi.dedup.....e2ed4e83fbcc3560a77edd9fea4809a9 |
| قاعدة البيانات: | OpenAIRE |
Find this issue from the American Chemical Society | تدمد: | 15205002 08974756 |
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