Kai Ma, Wenjie Chen, Tifeng Jiao*, Xue Jin,
Yutao Sang, Dong Yang, Jin Zhou, Minghua Liu*, Pengfei Duan*. Boosting
Circularly Polarized Luminescence of Small Organic Molecules via
Multi-dimensional Morphology Control. Chemical Science, Chem. Sci., 2019, Accepted Manuscript, DOI: 10.1039/C9SC01577A
Abstract
Achieving a higher dissymmetry factor is a crucial issue in developing circularly polarized luminescence (CPL) materials. Here, by tailorig the solvent composition and the morphology of the same chiral emissive small molecules (R- or S-SPAn), circularly polarized emission with boosted dissymmetry factor (two order) were realized. It was found that by regulatig the water fraction in the mixed THF/H2O, we were able to achieve kinetic control over chiral emissive R- or S-SPAn association into various nanostructures with 0D nanospheres, 2D nanoflakes and 3D stacked nanoflakes. These nanostructures are all CPL active. Remarkably, the dissymmetry factors of the nanostructures were significantly enhanced from that of molecule and further boosted in different morphologies, which is from ~10-4 (0D nanospheres) to 10-3 (2D flake) to ~10-2 (3D nanoflakes). The enlarged glum value could be assigned to a well-packing induced strong luminescence of excimer. This strategy provide an efficient way for fabricating higher dissymmetry factor CPL organic nanomaterials by only changing the supramolecular architectures while using the same chiral small molecules.
