Three‐Dimensionally Anchored Multiple Resonance Emitters via Intramolecular Noncovalent Interaction Enhancement for Efficient, Stable, and Narrowband Blue OLEDs

Developing efficient and stable blue organic light-emitting diodes (OLEDs) remains challenging due to the inherent trade-off between efficiency and operational lifetime. While multiple resonance thermally activated delayed fluorescence emitters offer narrowband emission with reduced excited-state energy, their planar structure, long-lived excitons, and deep highest occupied molecular orbital levels cause detrimental aggregation and instability. Here, we introduce a "3D anchoring" strategy that strategically enhances intramolecular noncovalent interactions. A sterically encumbered, sandwich-like architecture with carbazole-based dual anchors simultaneously suppresses π-π stacking and reinforces bond dissociation energy, boosting intrinsic stability. The proof-of-concept emitters demonstrate bright blue photoluminescence in solution, with photoluminescence quantum yields surpassing 92% and exceptionally narrow emission bands down to 18 nm. The corresponding optimized OLED device achieves a maximum external quantum efficiency of 38.2%, alongside record-high current and power efficiencies (59.2 cd A⁻ ¹ and 66.8 lm W⁻ ¹, respectively), excellent color purity (CIEy < 0.25), and a 2.3-fold improvement in operational lifetime. This work thereby presents a widely applicable design principle for next-generation high-performance blue emitters.