White Circularly Polarized OLEDs Enabled by Orthogonal Engineering of Achiral Thermally Activated Delayed Fluorescence Emitters and Chiral Assemblies

Abstract

AbstractThe development of white circularly polarized organic light‐emitting diodes (CP‐OLEDs) faces a critical challenge in simultaneously achieving high external quantum efficiency (EQE) and large dissymmetry factors (g), due to the inherent trade‐off between exciton utilization and chirality amplification. Herein, we propose an orthogonal architecture synergizing an achiral blue thermally activated delayed fluorescence (TADF) emitter with chiral orange assemblies to overcome this limitation. The chiral assemblies, featuring exceptional chiroptical activity (|gabs| = 0.95 and |glum| = 0.85), are engineered as both photon‐selective filters and emitters. When integrated with a blue TADF layer, this dual‐layer design enables 100% internal quantum efficiency through TADF‐enabled triplet harvesting and chiral amplification via selective absorption of blue photons with a specific polarization direction, generating amplified white circularly polarized electroluminescence (CPEL). The resulting white CP‐OLED (CIE: 0.31, 0.34) achieves a record |gEL| of 0.34 alongside an EQEmax of 6.3%, demonstrating the unprecedented white CP‐OLEDs when considering both EQE and gEL values. By optimizing the TADF doping ratio, a cool‐white CP‐OLED is realized with an EQE of 14.7% and |gEL| of 0.32. This work establishes a material orthogonal engineering to decouple exciton‐chirality interdependencies, opening avenues for fabricating high‐performance CPEL devices.