9-(3-(9H-Carbazol-9-yl)-5-(phenylsulfonyl)phenyl)-9H-carbazole (mCPSOB) is an ambipolar host thermally activated delayed fluorescence (TADF) material containing two electron-donating carbazole groups and one electron-accepting diphenylsulfonyl group.
mCPSOB has a high energy level of the triplet state (3.02 eV), which suppresses triplet exciton quenching and results in higher external quantum efficiency (EQE). Higher triplet energy level also makes it ideal as a host material for blue/deep blue dopants.
Compared to mCP, mCPSOB has a higher glass transition temperature (Tg = 140 °C). In return, this can prevent mCPSOB from crystallizing during operation and reduces the possibility of phase separation - thus significantly improving device thermal and morphological stability.
HOMO 5.8 eV, LUMO 2.5 eV;
ES = 2.93 eV, ET = 3.02 eV [1]
TGA > 200 °C (0.5% weight loss)
Tg = 140 °C