Planar Chiral [2.2]Paracyclophane-Based Thermally Activated Delayed Fluorescent Materials for Circularly Polarized Electroluminescence

This work describes the construction of a novel planar chiral [2.2]paracyclophane-based thermally activated delayed fluorescence (TADF)-active molecule with circularly polarized luminescence (CPL). The combination of the bulky planar chiral phenoxazinephane (PXZp) donor based [2.2]paracyclophane and triazine acceptor enables the highly efficient luminescence performances and excellent CPL properties. The enantiomers exhibit excellent TADF activities, the energy difference (ΔEST) between singlet and triplet of the molecule is only 0.03 eV. Notably, through solution-process, a yellow CP-OLEDs based on the molecule as the emitting layers displays high maximum brightness (Lmax) up to 34 293 cd m–2, maximum external quantum efficiency (EQEmax) up to 7.8% and remarkable CP-EL signal with gEL factor up to 4.6 × 10–3.