| 초록 |
Harvesting triplet excited states resulting from electrical pumping has been issued for efficient organic light-emitting diodes (OLEDs). Heavy metal complexes, thermally activated delayed fluorescence (TADF) materials, and exciplexes facilitate efficient triplet-harvesting by using spin mixing process in emitters, but its slow decay process results in short device lifetime. Therefore, using conventional fluorescent molecules can be an alternative if we can find a method to increase the triplet-harvesting. Here, we report the method of using both sensitization and induced heavy atom effects to harness triplet excited states for efficient fluorescent OLEDs. The method successfully facilitated efficient fluorescent OLED with the external quantum efficiency (EQE) of 26.1%. Large portion of singlet exciton formation on the conventional fluorescent emitter due to energy transfer process reduced exciton lifetime, resulting in reduced exciton-polaron quenching and improved device stability. |
