Synergistic Intramolecular Non‐Covalent Interactions Enable Robust Pure‐Blue TADF Emitters

Abstract Stability‐issues of organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) require further advancements, especially in pure‐blue range of CIE _y < 0.20, existing a dilemma between color purity and device lifetime. Though improving bond‐dissociation‐energy (BDE) can effectively improve material intrinsic stability, strategies to simultaneously improve BDE and photophysical performances are still lacking. Herein, it is disclosed that synergistic intramolecular non‐covalent interactions (Intra‐NI) can achieve not only the highest C─N BDE among blue TADF materials, but enhanced molecular‐rigidity, near‐unity photoluminescent quantum yields and short delayed lifetime. Pure‐blue TADF‐OLEDs based on proof‐of‐concept TADF material realize high external‐quantum‐efficiency and record‐high LT ₈₀ @500 cd m ⁻² of 109 h with CIE _y = 0.16. Furthermore, deep‐blue TADF‐sensitized devices exhibit high LT ₈₀ @500 cd m ⁻² of 81 h with CIE _y = 0.10. The findings provide new insight into the critical role of Intra‐NI in OLED materials and open the way to tackling vexing stability issues for developing robust pure‐blue organic emitters and other functional materials.