Multifunctional Hot‐Exciton Fluorophore Enabling Efficient Non‐Doped Blue Electron‐Fluorescence with Negligible Efficiency Roll‐Off and Phosphorescent OLEDs with Ultra‐Low Power Consumption

Abstract One of the most critical challenges in organic light‐emitting diodes (OLEDs) is the development of efficient blue emitters, which require high exciton utilization efficiency, short exciton lifetime, and well‐balanced carrier mobility. Herein, a blue hot exciton emitter, TPA‐SBF‐OXZ, is synthesized by incorporating a triphenylamine donor and an oxadiazole acceptor into the spirobifluorene (SBF) skeleton. TPA‐SBF‐OXZ exhibits a high photoluminescence quantum yield of 70.7%, and balanced hole and electron mobilities in neat film. Additionally, due to the anti‐aggregation‐caused‐quenching characteristics of the SBF skeleton, the non‐doped OLED achieves a maximum external quantum efficiency (EQE) of 10.6% at 2396 cd cm⁻² and 10.2% even at 11181 cd cm⁻², ranking the leading position in non‐doped blue fluorescent OLEDs. The proof‐of‐concept phosphorescent OLED using TPA‐SBF‐OXZ as host achieves remarkable performance metrics, including an ultra‐low turn‐on voltage of 2.2 V, a high EQE of 30.4%, a maximum power efficiency of 109.1 lm W⁻¹, and an exceptionally high luminance of over 130000 cd m⁻². This work offers a feasible approach for the development of high‐performance non‐doped blue electro‐fluorescence and low power‐consumption PhOLEDs.