Strategic Management of High‐Lying Triplet Excitons to Realize the Breakthrough in Efficiency of Blue Fluorescence OLEDs Based on AIE Emitter

Abstract Aggregation‐induced emission (AIE) materials are attractive for the fabrication of high‐efficiency organic light‐emitting diodes (OLEDs) owing to “hot exciton” process by reverse intersystem crossing (hRISC) and high photoluminescence quantum yields (PLQY). However, internal conversion (IC) from high‐lying triplet excitation states (T n , n≥2) lower excited state n‐1 ) is inevitable, resulting in severe exciton losses. Herein, an effective device structure designed that reuses lost excitons caused IC realizes breakthrough efficiency blue fluorescence OLEDs based on AIE molecule as emitter. The maximum external reached 14.8% kept at 14.4% luminance 1000 cd m −2 . In device, a triplet–triplet annihilation (TTA) up‐conversion material 1‐[2,5‐dimethyl‐4‐(1‐pyrenyl)phenyl]pyrene (DMPPP) introduced into emitter sensitizer receive excitons, thin TTA layer 9‐[4‐(10‐phenyl‐9‐anthryl)phenyl]‐9H‐carbazole (CzPA) middle doped form emissive (EML). It found hRISC iTPB‐2AC greatly enhances utilization intermediate ([TT]*) CzPA so maximized. This work establishes physical insights OLEDs.