Emitting Materials for Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes Using Benzofurocarbazole and Benzothienocarbazole as Donor Moieties

摘要

Thermally activated delayed fluorescent (TADF) emitting materials, 4,5-bis(benzofuro[3,2-c]carbazol-5-yl)phthalonitrile (BFCzPN) and 4,5-bis(benzo[4,5]thieno[3,2-c]carbazol-5-yl)phthalonitrile (BTCzPN), were synthesized and fabricated as organic light emitting diodes (OLEDs). Benzofurocarbazole and benzothienocarbazole were used as donors and phthalonitrile was an acceptor. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) distribution of BFCzPN and BTCzPN were well separated and small singlet-triplet energy gap of 0.13 and 0.17 eV were measured, respectively. BFCzPN and BTCzPN showed 12.4 and 11.8% of maximum quantum efficiency as thermally activated delayed fluorescent emitters.