We demonstrate a promising molecular design approach to achieve short exciton lifetime, small singlet and triplet energy splitting and high photoluminescence quantum yield in thermally activated delayed fluorescence emitters for high quantum efficiency and low efficiency roll-off characteristics in OLEDs.

We report a new electron donor moiety (diindolocarbazole) for high performances of thermally activated delayed fluorescence emitters.

In this study, we present optical simulation versus real fabricated device results in the micro-cavity red top-emitting organic light emitting diodes (TEOLEDs). The optical simulation results indicate that the two kinds of possible emissive layer (EML) positions exist in the second order micro-cavity effect and each EMLs could emit the similar radiance with near National Television System Committee (NTSC) color coordinate. Expected current efficiency and external quantum efficiency by the optical simulation toward the surface normal in the red tandem TEOLED are 98.8 cd/A and 22.6% for two EMLs, while fabricated device shows 95.8 cd/A and 26.5%, respectively.

The TADF OLEDs based on these silane-core host materials showed a maximum EQE of up to 18.8%.