Hydrogen bond-modulated molecular packing and its applications in high-performance non-doped organic electroluminescence

Exploiting high-performance non-doped organic light-emitting diodes (OLEDs) is a step towards future commercial application requirements, but great challenges remain due to quenching related to intermolecular triplet interaction. In this work, a novel strategy of exploiting high-performance non-doped electroluminescence via tuning intermolecular hydrogen bonding is demonstrated. Suitable intermolecular hydrogen bonding enables formation of a 3D supramolecular framework, which not only evidently restricts the nonradiative process and suppresses the triplet exciton quenching caused by π-π stacking of triplets, but also favors the horizontal molecular orientations especially in their non-doped states. The non-doped OLED based on the thermally activated delayed fluorescence emitter mTPy-PXZ with such suitable intermolecular hydrogen bonds exhibits the state-of-the-art performance with maximum external quantum efficiency of up to 23.6% with only 7.2% roll-off at 1000 cd m^-2. Moreover, it is the first report that the performance of an OLED with a non-doped emitting layer can surpass its corresponding optimized doped device. It is believed that this hydrogen bond-modulated mechanism can not only provide a new pathway for designing emitters for high-performance non-doped organic electroluminescence, but also has great potential in other solid-state luminescence applications.