2,3‐Disubstituted Fluorene Scaffold for Efficient Green Phosphorescent Organic Light‐Emitting Diodes

Fluorene is a classic three‐membered polycyclic aromatic hydrocarbon, and it has been widely used in optoelectronic devices. Here we explore a simple and efficient strategy for the derivatization at the 2‐ and 3‐ positions in fluorene unit. By introducing different types of substituents, we design two pairs of 2,3‐disubstituted fluorene isomers and use them as host materials for phosphorescent organic light‐emitting diodes (PHOLEDs). The green PHOLEDs hosted by these fluorene derivatives realize high external quantum efficiencies (EQE) over 20 % with low efficiency roll‐off. Particularly, the devices hosted by 2TRz3TPA and 2TPA3TRz achieve nearly 24 % EQE and 104 lm W−1 power efficiency. These results clearly demonstrate that the 2,3‐disubstituted fluorene platforms are potentially useful for constructing host materials. 2,3‐Disubstituted fluorene platforms for the construction of high‐efficiency host materials for green phosphorescent organic light‐emitting diodes.