| abstract |
The invention discloses an organic electroluminescent device. The luminescent layer includes a host material and a guest material. The host material is an exciplex formed by an electron donor material and an electron acceptor material, and the guest material is a thermally activated delayed fluorescent material. , the singlet energy level of the host material is lower than that of the guest material. Since the singlet energy level of the exciplex as the host material in the light-emitting layer is lower than that of the thermally activated delayed fluorescent material, the generation of high-energy excitons is avoided, and the molecular bond breakage caused by high excitation energy is effectively suppressed; The singlet energy level of the exciplex is low, which is beneficial to reduce the excitation energy of the excitons in the device, and suppress the triplet-triplet annihilation, triplet-polaron annihilation and singlet-triplet annihilation in the device. Reduce the efficiency roll-off of the device and prolong the life of the device. |