Chiral thermally activated delayed fluorescence emitters with dual conformations based on a pair of enantiomeric donors containing asymmetric carbons

Thermally activated delayed fluorescence (TADF) chiral emitters attract widespread attention due to their high exciton utilization as well as potential applications. In this work, we developed a pair of chiral donors, (R) and (S)-9-methyl-2,9-diphenyl-9,10-dihydroacridine (PMAc), for general TADF molecular design. The enantiomers (R) and (S)-TTR-PMAc are accordingly constructed. Interestingly, they are not only TADF emitters, but also possess dual stable conformations, i.e. nearly planar and nearly orthogonal conformations. (R) and (S)-TTR-PMAc show similar physical properties under conventional non-polarized environment. While under chiroptical environments, they exhibit obvious mirror-like circular dichroism (CD) and circularly polarized luminescence (CPL) properties. Moreover, by further comparing the CPL properties originated from each conformer, we confirm that molecular conformations can significantly influence the chiroptical performance.