Accessing S <sub>n≥2</sub> States of a TADF Emitter by Femtosecond NIR Spectroscopy
A thermally activated delayed fluorescence (TADF) emitter consisting of a triarylamine (TAA) donor and a 1,4-dicyanobenzene (DCN) acceptor moiety was characterized by femtosecond UV-Vis and near infrared (NIR) spectroscopy. The combination of the two techniques allows to probe spectral changes of the emitter in a range extending from 350 to 1600 nm. With the approach, low-lying higher singlet excitations (S<sub>n≥2</sub>) contributing to intersystem crossing via spin vibronic mechanisms can be located energetically. Due to the charge transfer (CT) character of the S<sub>1</sub> state, the transition energies S<sub>1</sub>→S<sub>n≥2</sub> are strongly solvent dependent as experiments on TAA-DCN dissolved in cyclohexane, toluene, 1,2-dimethoxyethane, and acetonitrile indicate. The experiments also hold information on dielectric and vibrational relaxation ensuing S<sub>1</sub> excitation.
Authors
- Wiebke Haselbach (ORCID: https://orcid.org/0000-0002-3813-275X)
- Peter Gilch (ORCID: https://orcid.org/0000-0002-6602-9397)
- Thomas J. J. Müller (ORCID: https://orcid.org/0000-0001-9809-724X)
- Simon L. Zimmermann (ORCID: https://orcid.org/0009-0009-1404-7612)
- Andreas Prüfer
- Barbara E. Nogueira de Faria
- Monika Flörke (ORCID: https://orcid.org/0009-0006-7151-7025)
- Jasmin Matthes
Institutions
- TU Dortmund University (DE)
- Heinrich Heine University Düsseldorf (DE)
Publication Details
- Journal
- Chemistry - A European Journal
- Published
- 2026-03-23
- DOI
- https://doi.org/10.1002/chem.70875
- Primary Topic
- Organic Light-Emitting Diodes Research
- Type
- article
- Field-Weighted Citation Impact
- 0.00