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Delayed Blue Fluorescence via Upper-Triplet State Crossing from C–C Bonded Donor–Acceptor Charge Transfer Molecules with Azatriangulene Cores
[Image: see text] 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 usu...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011764/ https://www.ncbi.nlm.nih.gov/pubmed/32063676 http://dx.doi.org/10.1021/acs.chemmater.9b01184 |
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author | Ward, Jonathan S. Kukhta, Nadzeya A. dos Santos, Paloma L. Congrave, Daniel G. Batsanov, Andrei S. Monkman, Andrew P. Bryce, Martin R. |
author_facet | Ward, Jonathan S. Kukhta, Nadzeya A. dos Santos, Paloma L. Congrave, Daniel G. Batsanov, Andrei S. Monkman, Andrew P. Bryce, Martin R. |
author_sort | Ward, Jonathan S. |
collection | PubMed |
description | [Image: see text] 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 ΔE(ST) 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. |
format | Online Article Text |
id | pubmed-7011764 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Chemical
Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-70117642020-02-12 Delayed Blue Fluorescence via Upper-Triplet State Crossing from C–C Bonded Donor–Acceptor Charge Transfer Molecules with Azatriangulene Cores Ward, Jonathan S. Kukhta, Nadzeya A. dos Santos, Paloma L. Congrave, Daniel G. Batsanov, Andrei S. Monkman, Andrew P. Bryce, Martin R. Chem Mater [Image: see text] 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 ΔE(ST) 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. American Chemical Society 2019-05-22 2019-09-10 /pmc/articles/PMC7011764/ /pubmed/32063676 http://dx.doi.org/10.1021/acs.chemmater.9b01184 Text en Copyright © 2019 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Ward, Jonathan S. Kukhta, Nadzeya A. dos Santos, Paloma L. Congrave, Daniel G. Batsanov, Andrei S. Monkman, Andrew P. Bryce, Martin R. Delayed Blue Fluorescence via Upper-Triplet State Crossing from C–C Bonded Donor–Acceptor Charge Transfer Molecules with Azatriangulene Cores |
title | Delayed Blue Fluorescence via Upper-Triplet State
Crossing from C–C Bonded Donor–Acceptor
Charge Transfer Molecules with Azatriangulene Cores |
title_full | Delayed Blue Fluorescence via Upper-Triplet State
Crossing from C–C Bonded Donor–Acceptor
Charge Transfer Molecules with Azatriangulene Cores |
title_fullStr | Delayed Blue Fluorescence via Upper-Triplet State
Crossing from C–C Bonded Donor–Acceptor
Charge Transfer Molecules with Azatriangulene Cores |
title_full_unstemmed | Delayed Blue Fluorescence via Upper-Triplet State
Crossing from C–C Bonded Donor–Acceptor
Charge Transfer Molecules with Azatriangulene Cores |
title_short | Delayed Blue Fluorescence via Upper-Triplet State
Crossing from C–C Bonded Donor–Acceptor
Charge Transfer Molecules with Azatriangulene Cores |
title_sort | delayed blue fluorescence via upper-triplet state
crossing from c–c bonded donor–acceptor
charge transfer molecules with azatriangulene cores |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7011764/ https://www.ncbi.nlm.nih.gov/pubmed/32063676 http://dx.doi.org/10.1021/acs.chemmater.9b01184 |
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