Enhancing Circularly\nPolarized Luminescence Dissymmetry\nFactor of Chiral Cylindrical Molecules to −0.56 through Intramolecular\nShort-Range Charge Transfer

High-performance circularly polarized luminescent (CPL)\nmaterials\nhave received wide attention recently by virtue of broad application\nin circularly polarized light-emitting diodes, 3D display, and encryption.\nReaching both high luminescence efficiency and strong luminescence\ndissymmetry factor (<i>g</i><sub>lum</sub>) is still a challenging\ngoal that requires continuous efforts. Herein, we performed a systematic\ntheoretical investigation on the chiroptical properties of helical\ncylindrical molecules (−)-[4]cyclo-2,6-anthracene [(−)-[4]CA<sub>2,6</sub>] and (<i>P</i>)-[4]cyclo-2,8-chrysenylene [(<i>P</i>)-[4]CC<sub>2,8</sub>], and found that the unique and symmetric\ncylindrical structure could make the transition dipole moment components\noffset along the cylindrical surface but concentrated along the vertical\ncentral axis. This structural superiority contributes the collinear\nelectric and magnetic transition dipole moment vectors and thus the\nlarge <i>g</i><sub>lum</sub>. Based on the results of decomposed\ntransition dipole moment vectors to individual atoms, an effective\nstrategy to enhance the <i>g</i><sub>lum</sub> through introducing\nintramolecular short-range charge transfer by embedding B,N atoms\nis proposed. The decreased electric transition dipole moment and well-kept\nmagnetic transition dipole moment enable the <i>g</i><sub>lum</sub> of B,N-embedded designed molecules (−)-[4]CA<sub>2,6</sub>-4BN and (<i>P</i>)-[4]CC<sub>2,8</sub>-4BN up\nto −0.31 and −0.56, respectively. This molecular-insight\ninvestigation deepens the understanding of the structure–property\nrelationship and provides efficient guidance for improving <i>g</i><sub>lum</sub> of CPL materials.