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 (Delta E-ST) 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 (L-max) up to 34 293 cd m(-2), maximum external quantum efficiency (EQE(max)) up to 7.8% and remarkable CP-EL signal with g(EL) factor up to 4.6 x 10(-3).