Thermally Activated Delayed Fluorescence Mediated through the Upper Triplet State Manifold in Non-Charge-Transfer Star-Shaped Triphenylamine-Carbazole Molecules

Piotr Pander, Radoslaw Motyka, Pawel Zassowski, Marc K. Etherington, Daniele Varsano, Tales J. Da Silva, Marilia J. Caldas, Przemyslaw Data*, Andrew P. Monkman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)
47 Downloads (Pure)

Abstract

Thermally activated delayed fluorescence has been found in a group of tricarbazolylamines that are purely electron-donating, non-charge-transfer (CT) molecules. We show that the reverse intersystem crossing step in these materials is mediated through upper triplet states. Reverse internal conversion is shown to be the thermally activated mechanism behind the triplet harvesting mechanism. The strongly mixed n-π∗/ π- π∗ character of the lowest energy optical transitions retains high oscillator strength and gives rise to high φPL. Organic light-emitting diode devices using these materials were fabricated to show very narrow (full width at half-maximum = 38-41 nm) electroluminescence spectra, clearly demonstrating the excitonic nature of the excited states. This new combination of physicochemical properties of a non-CT molecule yields thermally activated delayed fluorescence, but via a different, physical mechanism, reverse internal conversion delayed fluorescence.

Original languageEnglish
Pages (from-to)23934-23942
Number of pages9
JournalJournal of Physical Chemistry C
Volume122
Issue number42
Early online date28 Sep 2018
DOIs
Publication statusPublished - 25 Oct 2018

Fingerprint Dive into the research topics of 'Thermally Activated Delayed Fluorescence Mediated through the Upper Triplet State Manifold in Non-Charge-Transfer Star-Shaped Triphenylamine-Carbazole Molecules'. Together they form a unique fingerprint.

Cite this