Circularly Polarized Luminescence From Chiral Conjugated Poly(Carbazole-Ran-Acridine)s With Aggregation-Induced Emission And Delayed Fluorescence

Pure organic materials with circularly polarized luminescence (CPL) and delayed fluorescence have gained increasing interest from academic and technological areas. To enhance the solid-state emission and exciton utilization in chiral optoelectronic devices, a synthetic strategy to impart conjugated polymers with CPL and aggregation-induced delayed fluorescence was proposed. Herein, two conjugated macromolecules with electron-donating poly(carbazole-ran-acridine) backbones, electron-withdrawing dibenzothiophen-2-yl(phenyl)methanone, and chiral alanine moieties were designed and synthesized. Their neat films exhibited strong green emission with quantum yields of 6.7 and 10.3% and delayed fluorescence with a lifetime of 1.358 and 1.366 μs, respectively. Both the Cotton effect and CPL with a dissymmetry factor of −2.01 × 10–3 and −1.39 × 10–3 were determined in the solid state. Such unique conjugated polymers were employed as solution-processed emitting layers in organic light emitting diodes, which displayed a maximum brightness of 1477 cd/m2 and maximum current efficiency of 2.52 cd/A.