A Diboron-Based Thermally Activated Delayed Fluorescent Material for Versatile Applications of Organic Light-Emitting Diodes

Thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) have attracted public attention due to their high external quantum efficiency (EQE) and implication in future display technology. Despite their improved efficiency, TADF-based OLEDs still suffer from serious efficiency roll-off and short operational lifetimes. Herein, a diboron-based molecule, PhCzDBA, is designed and its device exhibits a maximum EQE (EQE max ) of 33.8% and only slight roll-off (EQE max of 31.5% at 1000 cd m –2 and 28.8% at 3000 cd m –2 ). Furthermore, it shows superior stability among reported TADF devices (LT 80 of 113 h at the initial luminance of 3000 cd m –2 ). Remarkably, its nondoped OLED shows a high EQE max of 17.7% with a λ max > 580 nm, surpassing most orange nondoped OLEDs. Moreover, a decent white OLED device with an EQE max of 16.4% and a color rendering index (CRI) of 73 can be achieved by incorporating a simple sandwich emitting layer configuration, exhibiting the potential and diverse applications in many aspects.