Towards Efficient and Stable Donor-Acceptor Luminescent Radicals
© 2022 Wiley-VCH GmbH.
| Publié dans: | Advanced materials (Deerfield Beach, Fla.). - 1998. - 35(2023), 6 vom: 17. Feb., Seite e2208190 |
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| Auteur principal: | |
| Autres auteurs: | , , , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2023
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| Accès à la collection: | Advanced materials (Deerfield Beach, Fla.) |
| Sujets: | Journal Article charge transfer state local-excitation state luminescent radicals photoluminescent quantum efficiency stability |
| Résumé: | © 2022 Wiley-VCH GmbH. In contrast to closed-shell luminescent molecules, the electronic ground state and lowest excited state in organic luminescent radicals are both spin doublet, which results in spin-allowed radiative transitions. Most reported luminescent radicals with high photoluminescent quantum efficiency (PLQE) have a donor-acceptor (D-A•) chemical structure where an electron-donating group is covalently attached to an electron-withdrawing radical core (A•). Understanding the main factors that define the efficiency and stability of D-A• type luminescent radicals remains challenging. Here, we designed and synthesized a series of tri(2,4,6-trichlorophenyl)methyl (TTM) radical derivatives with donor substituents varying by their extent of conjugation and their number of imine-type nitrogen atoms. The experimental results suggest that the luminescence efficiency and stability of the radicals are proportional to the degree of conjugation but inversely proportional to the number of imine nitrogen atoms in the substituents. These experimental trends are very well reproduced by density functional theory calculations. The theoretical results indicate that both the luminescence efficiency and radical stability are related to the energy difference between the charge transfer (CT) and local-excitation (LE) states, which decreases as either the number of imine nitrogen atoms in the substituent increases or its conjugation length decreases |
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| Description: | Date Completed 10.02.2023 Date Revised 10.02.2023 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1521-4095 |
| DOI: | 10.1002/adma.202208190 |