High-Efficiency Organic Light-Emitting Diodes with Exciplex Host
Exciplex forming co-hosts have been applied to fabricate highly efficient organic light-emitting diodes (OLEDs) due to the merits of bipolarity, 100% exciton harvesting, preferred dipole alignment, and sensitizing effect. We review the discovery and development of the exciplex mechanism framework, from its finding to the successful application as hosts for phosphorescent OLEDs (PhOLEDs), thermally activated delayed fluorescence (TADF) OLEDs, traditional fluorescent OLEDs, as well as in white OLEDs (WOLEDs). The exciplex forming co-hosts utilize the TADF effect to guarantee the high exciton utilization efficiency. The charge-injection-free energy level configuration decrease the driving voltages and bring about improved power efficiency. The increased transitional dipole moment of emitters in exciplex forming co-host add outcoupling efficiency to efficiency limit. Exciplex with TADF also shows sensitizing effect, making high-efficiency fluorescent OLEDs possible. This review introduces the progressive achievement of the exciplex forming co-host, aimed at forming a stage study and summary of the exciplex based OLEDs, and hopefully help researchers grasp the future developing trend and challenges of the exciplex forming co-host.
- This article is part of the themed collection: Recent Review Articles