Lookup NU author(s): Jamie Gibson,
Dr Thomas Penfold
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
Knowing the underlying photophysics of thermally activated delayed fluorescence (TADF) allows proper design of high efficiency organic light-emitting diodes. We have proposed a model to describe reverse intersystem crossing (rISC) in donor–acceptor charge transfer molecules, where spin–orbit coupling between singlet and triplet states is mediated by one of the local triplet states of the donor (or acceptor). This second order, vibronically coupled mechanism describes the basic photophysics of TADF. Through a series of measurements, whereby the energy ordering of the charge transfer (CT) excited states and the local triplet are tuned in and out of resonance, we show that TADF reaches a maximum at the resonance point, substantiating our model of rISC. Moreover, using photoinduced absorption, we show how the populations of both singlet and triplet CT states and the local triplet state change in and out of resonance. Our vibronic coupling rISC model is used to predict this behaviour and describes how rISC and TADF are affected by external perturbation.
Author(s): Etherington M, Gibson J, Higginbotham HF, Penfold TJ, Monkman AP
Publication type: Article
Publication status: Published
Journal: Nature Communications
Online publication date: 30/11/2016
Acceptance date: 25/10/2016
Date deposited: 01/12/2016
ISSN (electronic): 2041-1723
Publisher: Nature Publishing Group
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