A Thermally Activated Delayed Fluorescence Emitter Investigated by Time‐Resolved Near‐Infrared Spectroscopy. Issue 2 (17th November 2022)

• Record Type: Journal Article
• Authors: Haselbach, Wiebke; Kaminski, Jeremy M.; Kloeters, Laura N.; Müller, Thomas J. J.; Weingart, Oliver; Marian, Christel M.; Gilch, Peter; Nogueira de Faria, Barbara E.
• Is Part Of: Chemistry. Volume 29:Issue 2(2023)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-11-17
• Subjects: intersystem crossing -- NIR spectroscopy -- thermally activated delayed fluorescence -- time-resolved spectroscopy -- UV/VIS spectroscopy; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202202809
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: Emitters for organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) require small singlet (S1 )‐triplet (T1 ) energy gaps as well as fast intersystem crossing (ISC) transitions. These transitions can be mediated by vibronic mixing with higher excited states S n and T n ( n =2, 3, 4, …). For a prototypical TADF emitter consisting of a triarylamine and a dicyanobenzene moiety (TAA‐DCN) it is shown that these higher states can be located energetically by time‐resolved near‐infrared (NIR) spectroscopy. Abstract : A metal‐free TADF (thermally activated delayed fluorescence) emitter was investigated by time‐resolved near‐infrared spectroscopy. This enabled upper excited states that contribute to spin‐vibronic coupling to be detected.