講演情報
[8p-N206-2]Effect of Shielding Substituents on Performance of Blue Thermally Activated Delayed Fluorescent Molecules
〇(D)Gerardus Iswara Lestanto1, Debasish Barman1, Hajime Nakanotani2, Chin-Yiu Chan3, Chihaya Adachi1 (1.Kyushu University, 2.Hokkaido University, 3.City University of Hong Kong)
キーワード：
Organic Light-Emitting Diode (OLED)、Thermally Activated Delayed Fluorescence (TADF)
In designing efficient and stable blue thermally activated delayed fluorescence (TADF) molecules aimed for high-performance organic light-emitting diodes (OLEDs), accelerating the reverse intersystem crossing rate constant (kRISC) is the primary factor in reducing triplet population during OLED operation. However, despite significant efforts to improve kRISC, the device operational lifetimes of blue TADF-OLEDs remain insufficient for commercial viability. On the other hand, another critical issue originates from intermolecular interactions during electrical excitation, leading to unwarranted degradation events such as exciton-polaron annihilation. Thus, “shielding” substituents are incorporated to protect the emitter molecules from unwarranted intermolecular interactions. To address this issue, we designed six TADF emitters having progressively bulkier shielding substituents: 1Ph, 2Ph, 3Ph, 4Ph, CzPh, and m2PhCz. In this work, we selected 1Ph as a reference compound to evaluate the shielding effect on optical and electrical properties. Notably, this approach proved effective, as device lifetimes significantly improved from 3Ph to 4Ph, CzPh, and m2PhCz while maintaining nearly the same kRISC.