Decoupling Charge Transport and Chiral Emission in Narrowband CP‐OLEDs via Synergistic Chiral Supramolecular Assembly and Interlayer Sensitization

Chiral co‐assemblies with helical nanofibers are promising for achieving high dissymmetry factors ( g EL ) in circularly polarized organic light‐emitting diodes (CP‐OLEDs). However, enhancing device efficiency typically necessitates complex multi‐component systems, which often compromise the ordered structure. Herein, we propose an interlayer sensitization strategy that spatially decouples the sensitizer from the chiral supramolecular co‐assembled emitting layer. Two pairs of chiral co‐assemblies, R / S ‐PF: 3 wt.% TBN‐TPA and R / S ‐PF: 3 wt.% DtBuCzB, were prepared using PF8 as assembly host, R / S ‐5011 as chiral inducers, and TBN‐TPA and DtBuCzB as narrowband emitters. While the non‐sensitized devices exhibited favorable narrowband circularly polarized electroluminescence with | g EL | of 0.036/0.017, their maximum external quantum efficiency (EQE max ) limited at 0.81%/1.1% and 0.35%/0.32%. Specifically, the sensitized blue CP‐OLEDs based on R / S ‐PF: 3 wt.% TBN‐TPA achieved a 3‐fold increase in EQE max (up to 2.43%/2.48%) while maintaining high | g EL |of 0.032). Similarly, the sensitized cyan CP‐OLEDs based on R / S ‐PF: 3 wt.% DtBuCzB demonstrated a 6‐fold efficiency enhancement, reaching EQE max of 2.11%/1.86%. By incorporating an interlayer sensitization strategy, we significantly boosted exciton utilization through interfacial energy transfer while preserving the chiral supramolecular architecture. This synergy of decoupling charge transport and chiral emission provides a robust, effective pathway for developing high‐performance CP‐OLEDs that integrate large g EL value, high efficiency, and narrowband emission.