초록 |
It is necessary to develop excellent hosts with emitter to obtain high efficiency organic light-emitting diodes (OLEDs). Various types of host materials have been reported recently, including unipolar, bipolar, and mixed hosts. Among them, mixed hosts, especially hosts that form exciplex, are being studied because of their many advantages. First, the mixed host is easy to adjust the ratio of the donor and acceptor, making it easier to control the charge balance. In particular, hosts that form exciplex have thermally activated delayed fluorescence (TADF) characteristics. Thus, exciplex forming hosts are efficient for energy transfer to TADF emitter. In this study, we synthesized a polymeric donor and a small molecular acceptor for the exciplex host system. Their blend film with green emitter showed fine surface morphology, good charge balance, and high photoluminescence quantum yield. Corresponding TADF OLEDs exhibited highly improved efficiencies compared to polymeric donor. |