OLEDs using molecular TADF materials as hosts

Thermally activated delayed fluorescence (TADF) in organic molecules has been discovered for decades. Since the concept of TADF for harvesting singlet and triplet excitons without incorporating noble metals was first introduced in organic light-emitting diodes (OLEDs), TADF materials have aroused huge attention in both academia and industry. Moreover, with donor and acceptor moieties, TADF materials are inherently bipolar, which potentially makes them an ideal host material for carriers balance and the triplet excitons upconvesion. Here, recent progresses on materials and mechanisms of high-performance devices with TADF hosts, including TADF-sensitized fluorescent OLEDs, TADF-sensitized phosphorescent OLEDs, and TADF-sensitized TADF-OLEDs are discussed.