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Updated: Nov 8, 2025

Scale-up Chemical Synthesis of Thermally-activated Delayed Fluorescence Emitters Based on the Dibenzothiophene-S,S-Dioxide Core
Published on: October 24, 2017
Molecular Vibration Accelerates Charge Transfer Emission in a Highly Twisted Blue Thermally Activated Delayed
Yoshimasa Wada1, Katsuyuki Shizu1, Hironori Kaji1
1Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Abstract:
In the development of new organic light-emitting diodes, thermally activated delayed fluorescence (TADF) materials have drawn interest because of their ability to upconvert electrically generated triplet excitons into singlets. Efficient TADF requires a well-balanced large transition dipole moment (μ) between the lowest excited singlet state (S1) and the ground state (S0) and a small energy splitting (ΔEST) between S1 and the lowest triplet state (T1). However, a number of highly twisted donor-acceptor-type TADF molecules have been reported to exhibit high performance in OLEDs, although these molecules may sacrifice μ in exchange for a very small ΔEST. Here, we theoretically investigate the origin of efficient emission from a perpendicularly twisted blue emitter, MA-TA. In this system, the μ value almost vanishes in the static approximation; however, vibrational contributions increase μ considerably. Hence, we show that the dynamics of excitons have a critical role in such TADF systems.
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