The application of charge transfer host based exciplex and thermally activated delayed fluorescence materials in organic light-emitting diodes

Here, we review systematically the applications of exciplex and thermally activated delayed fluorescence (TADF) materials as the host in organic light-emitting diodes (OLEDs), who is the charge transfer host based intermolecular and intra-molecular, respectively. Exciplex and TADF materials present many advantages of natural bipolarity, small singlet-triplet splitting energy and low driving voltage to act as the host rather than emitter. The applications of exciplex and TADF materials as the host in phosphorescent, fluorescent and white OLEDs are given and new challenges, suggestions are also provided finally for further research and potential development of this area.