Improving the TADF in Corannulene‐Based Emitters via Tuning the Strength of Donor and Acceptor Groups

Abstract

AbstractIn this investigation, a systematic study on the design and development of corannulene‐based thermally activated delayed fluorescence (TADF) emitters using density functional theory methods is carried out. Benzene, benzopyrazine, difluoro‐benzopyrazine, benzene‐1,2‐dithiol, and tetrasulfone are introduced on corannulene bowl as electron‐withdrawing groups to alter the electron‐accepting property of corannulene. Three different donors, viz., carbazole, phenoxazine, and 5,10‐dihydrophenazine are substituted on the rim position of corannulene to alter the absorption properties. The relationship between chemical structure and TADF property is established by evaluating the dihedral angle between donor and acceptor units, spin–orbit coupling (SOC) values, the energy difference between singlet‐triplet excited states (ΔEST), and rates of reverse intersystem crossing (kRISC). The newly designed TADF emitters show absorption in the blue to near‐IR regions depending on the strength of the donor and acceptor moieties. Careful analysis of these properties delineates the relationship between SOC values and the nature of the excited states, which is crucial for achieving high kRISC.