Molecular Design and Synthesis of Dicarbazolophane-Based Cen-trosymmetric through-Space Donors for Solution-Processed TADF OLEDs

Conjugation-extended carbazolophane donors, dicarbazolophanes (DCCP), were designed and synthesized by a multi-fold stepwise Pd-catalyzed Buchwald-Hartwig amination/ring cyclization process. Further, elaboration of the DCCP core is possible with introduction of pendant carbazole derivative groups. This provided a way of tuning the optoelectronic properties of the thermally activated delayed fluorescence (TADF) compounds DCCPTRZtBu2, dtBuCzDCCPTRZtBu2, and dMeOCzDCCPTRZtBu2. Solution-processed OLEDs were fabricated and achieved maxi-mum external quantum efficiencies (EQEmax) of 8.2% and EQE of 7.9% at 100 cd/m2.