Switchable Topologically Chiral [2]Catenane as Multiple Resonance Thermally Activated Delayed Fluorescence Emitter for Efficient Circularly Polarized Electroluminescence

Aiming at the fabrication of circularly polarized organic light‐emitting diodes (CP‐OLEDs) with high dissymmetry factors (gEL) and color purity through the employment of novel chiral source, topologically chiral [2]catenanes were first utilized as the key chiral skeleton to construct novel multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters. Impressively, the efficient chirality induction and unique switchable feature of topologically chiral [2]catenane not only lead to a high |gPL| value up to 1.6 × 10‐2 but also facilitate in situ dynamic switching of the full‐width at half‐maximum (FWHM) and circularly polarized luminescence (CPL). Furthermore, the solution‐processed CP‐OLEDs based on the resultant topologically chiral emitters exhibit reveal narrow FWHM of 36 nm, maximum external quantum efficiency of 17.6%, and CPEL with |gEL| of 2.1 × 10‐3. This study demonstrates the successful construction of the first CP‐MR‐TADF emitters based on topological chirality with the highest |gPL| among the reported CP‐MR‐TADF emitters and excellent device performance to the best of our knowledge. Moreover, it endowed the MR‐TADF emitter with distinctive switchable CPL performances, thus providing a novel design strategy as well as a promising platform for developing intelligent CP‐OLEDs.