Investigation of the Mechanisms Giving Rise to TADF in Exciplex States

dos Santos, Paloma Lays; Dias, Fernando B.; Monkman, Andrew P.

doi:10.1021/acs.jpcc.6b05198

Investigation of the Mechanisms Giving Rise to TADF in Exciplex States

dos Santos, Paloma Lays; Dias, Fernando B.; Monkman, Andrew P.

Authors

Paloma Lays dos Santos

Dr Fernando Dias f.m.b.dias@durham.ac.uk
Associate Professor

Professor Andrew Monkman a.p.monkman@durham.ac.uk
Professor

Abstract

The donor–acceptor systems studied in this work have been demonstrated to show strong exciplex formation by their red-shifted PL emission when compared with the individual donor and acceptor molecules, and all give rise to delayed fluorescence. In all cases, the channels by which this delayed fluorescence is generated, along with the energy levels involved in reverse intersystem crossing (rISC), that is, which triplet levels the charge-transfer states couple to yield spin flip, have not previously been identified. Here the intermolecular charge transfer states formed in the donor–acceptor molecular pairs are studied. It is demonstrated that the local triplet excited states are the states that couple to the singlet charge-transfer excited state, defining the rISC process and hence thermally activated delayed fluorescence (TADF) mechanism. Moreover, in most systems there is a competition between delayed fluorescence mechanisms, triplet triplet annihilation and TADF, and this is analysed in detail. New design rules for exciplex materials showing dominant delayed fluorescence due to rISC for the device based on TADF are elucidated.

Citation

dos Santos, P. L., Dias, F. B., & Monkman, A. P. (2016). Investigation of the Mechanisms Giving Rise to TADF in Exciplex States. Journal of Physical Chemistry C, 120(32), 18259-18267. https://doi.org/10.1021/acs.jpcc.6b05198

Journal Article Type	Article
Acceptance Date	Jul 19, 2016
Online Publication Date	Jul 26, 2016
Publication Date	Aug 18, 2016
Deposit Date	Nov 8, 2016
Publicly Available Date	Jul 26, 2017
Journal	Journal of Physical Chemistry C
Print ISSN	1932-7447
Electronic ISSN	1932-7455
Publisher	American Chemical Society
Peer Reviewed	Peer Reviewed
Volume	120
Issue	32
Pages	18259-18267
DOI	https://doi.org/10.1021/acs.jpcc.6b05198
Public URL	https://durham-repository.worktribe.com/output/1394065

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Copyright Statement
This document is the Accepted Manuscript version of a Published Work that appeared in final form in The Journal of Physical Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.jpcc.6b05198.