Presentation Information
[7a-N304-1]Investigation on Photophysical Properties of HzTFEX2
〇(M1)Hyunje Jung1, Youichi Tsuchiya1, Zachary Hudson2, Chihaya Adachi1,3 (1.OPERA, Kyushu Univ., 2.Dept. Chem., UBC., 3.I2CNER, Kyushu Univ)
Keywords:
TADF,Inverted S1-T1 gap,Emission mechanism
Thermally activated delayed fluorescence (TADF) materials are promising candidates for next-generation OLEDs due to their potential for 100% internal quantum efficiency enabled by a small singlet–triplet energy gap. HzTFEX2, reported by Aizawa et al. in 2022, exhibits an inverted S1–T1 configuration (InvEST), with a reverse intersystem crossing (kRISC) rate exceeding that of intersystem crossing under certain limiting conditions. However, discrepancies under different decay assumptions and recent theoretical studies highlight the need for deeper investigation. In this work, we examine the photophysical behavior of HzTFEX2 using temperature- and solvent-dependent emission decay analysis. By applying both dynamic three- and four-state kinetic models, we assess the validity of the InvEST assignment and provide a refined interpretation of its emission mechanism, offering insights into ΔEST estimation in systems with small or negative energy gaps.