Impact of Dielectric Constant on the Singlet-Triplet Gap in Thermally Activated Delayed Fluorescence (TADF) Materials

Handle URI:
http://hdl.handle.net/10754/623660
Title:
Impact of Dielectric Constant on the Singlet-Triplet Gap in Thermally Activated Delayed Fluorescence (TADF) Materials
Authors:
Sun, Haitao ( 0000-0001-8050-904X ) ; Hu, Zhubin; Zhong, Cheng; Chen, Xiankai; Sun, Zhenrong; Bredas, Jean-Luc ( 0000-0001-7278-4471 )
Abstract:
Thermally activated delayed fluorescence (TADF) relies on the presence of a very small energy gap, ΔEST, between the lowest singlet and triplet excited states. ΔEST is thus a key factor in the molecular design of more efficient materials. However, its accurate theoretical estimation remains challenging, especially in the solid state due to the influence of polarization effects. We have quantitatively studied ΔEST as a function of dielectric constant, ε, for four representative organic molecules using the methodology we recently proposed at the Tamm-Dancoff approximation ωB97X level of theory, where the range-separation parameter ω is optimized with the polarizable continuum model. The results are found to be in very good agreement with experimental data. Importantly, the polarization effects can lead to a marked reduction in the ΔEST value, which is favorable for TADF applications. This ΔEST decrease in the solid state is related to the hybrid characters of the lowest singlet and triplet excited states, whose dominant contribution switches to charge-transfer-like with increasing ε. The present work provides a theoretical understanding on the influence of polarization effect on the singlet-triplet gap and confirms our methodology to be a reliable tool for the prediction and development of novel TADF materials.
KAUST Department:
Laboratory for Computational and Theoretical Chemistry of Advanced Materials; Physical Sciences and Engineering (PSE) Division
Citation:
Sun H, Hu Z, Zhong C, Chen X, Sun Z, et al. (2017) Impact of Dielectric Constant on the Singlet–Triplet Gap in Thermally Activated Delayed Fluorescence Materials. The Journal of Physical Chemistry Letters: 2393–2398. Available: http://dx.doi.org/10.1021/acs.jpclett.7b00688.
Publisher:
American Chemical Society (ACS)
Journal:
The Journal of Physical Chemistry Letters
Issue Date:
28-Apr-2017
DOI:
10.1021/acs.jpclett.7b00688
Type:
Article
ISSN:
1948-7185
Sponsors:
This work has been supported by the National Natural Science Foundation of China (Award No. 21603074 and 11474096), Shanghai-International Scientific Cooperation Fund (16520721200), Program of Introducing Talents of Discipline to Universities 111 Project (B12024), and King Abdullah University of Science and Technology (KAUST). We are very grateful to the ECNU and KAUST IT Research Computing Teams for providing assistance and computational and storage resources. H.S. thanks Prof. Bing Yang, Prof. Qisheng Zhang, Dr. Paul Winget, and Dr. Ko Inada for stimulating discussions.
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b00688
Appears in Collections:
Articles; Physical Sciences and Engineering (PSE) Division

Full metadata record

DC FieldValue Language
dc.contributor.authorSun, Haitaoen
dc.contributor.authorHu, Zhubinen
dc.contributor.authorZhong, Chengen
dc.contributor.authorChen, Xiankaien
dc.contributor.authorSun, Zhenrongen
dc.contributor.authorBredas, Jean-Lucen
dc.date.accessioned2017-05-18T07:33:01Z-
dc.date.available2017-05-18T07:33:01Z-
dc.date.issued2017-04-28en
dc.identifier.citationSun H, Hu Z, Zhong C, Chen X, Sun Z, et al. (2017) Impact of Dielectric Constant on the Singlet–Triplet Gap in Thermally Activated Delayed Fluorescence Materials. The Journal of Physical Chemistry Letters: 2393–2398. Available: http://dx.doi.org/10.1021/acs.jpclett.7b00688.en
dc.identifier.issn1948-7185en
dc.identifier.doi10.1021/acs.jpclett.7b00688en
dc.identifier.urihttp://hdl.handle.net/10754/623660-
dc.description.abstractThermally activated delayed fluorescence (TADF) relies on the presence of a very small energy gap, ΔEST, between the lowest singlet and triplet excited states. ΔEST is thus a key factor in the molecular design of more efficient materials. However, its accurate theoretical estimation remains challenging, especially in the solid state due to the influence of polarization effects. We have quantitatively studied ΔEST as a function of dielectric constant, ε, for four representative organic molecules using the methodology we recently proposed at the Tamm-Dancoff approximation ωB97X level of theory, where the range-separation parameter ω is optimized with the polarizable continuum model. The results are found to be in very good agreement with experimental data. Importantly, the polarization effects can lead to a marked reduction in the ΔEST value, which is favorable for TADF applications. This ΔEST decrease in the solid state is related to the hybrid characters of the lowest singlet and triplet excited states, whose dominant contribution switches to charge-transfer-like with increasing ε. The present work provides a theoretical understanding on the influence of polarization effect on the singlet-triplet gap and confirms our methodology to be a reliable tool for the prediction and development of novel TADF materials.en
dc.description.sponsorshipThis work has been supported by the National Natural Science Foundation of China (Award No. 21603074 and 11474096), Shanghai-International Scientific Cooperation Fund (16520721200), Program of Introducing Talents of Discipline to Universities 111 Project (B12024), and King Abdullah University of Science and Technology (KAUST). We are very grateful to the ECNU and KAUST IT Research Computing Teams for providing assistance and computational and storage resources. H.S. thanks Prof. Bing Yang, Prof. Qisheng Zhang, Dr. Paul Winget, and Dr. Ko Inada for stimulating discussions.en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b00688en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.7b00688.en
dc.titleImpact of Dielectric Constant on the Singlet-Triplet Gap in Thermally Activated Delayed Fluorescence (TADF) Materialsen
dc.typeArticleen
dc.contributor.departmentLaboratory for Computational and Theoretical Chemistry of Advanced Materialsen
dc.contributor.departmentPhysical Sciences and Engineering (PSE) Divisionen
dc.identifier.journalThe Journal of Physical Chemistry Lettersen
dc.eprint.versionPost-printen
dc.contributor.institutionState Key Laboratory of Precision Spectroscopy, School of Physics and Materials Science, East China Normal University , Shanghai 200062, P. R. China.en
dc.contributor.institutionCollaborative Innovation Center of Extreme Optics, Shanxi University , Taiyuan, Shanxi 030006, P. R. China.en
kaust.authorSun, Haitaoen
kaust.authorZhong, Chengen
kaust.authorChen, Xiankaien
kaust.authorBredas, Jean-Lucen
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