LAUSR

The design of molecular optoelectronic materials based on fabricating polymorphs and/or co-crystals has been received much recent attention in the fields of luminescence, sensor, nonlinear optics, and so on. If combining the advantages of two crystal engineering strategies above, the diversity of self-assembly fashion and the tuning of photofunctional performances would be largely extended. However, such multi-component examples are still very limited to date. Herein, we report the construction of luminescent polymorphic co-crystals by assembly of tris(pentafluorophenyl)borane (TPFB) with 9,10-dicyanoanthracene (DCA) and acridine (AC) as paradigms. Different stacking modes and arrangement styles based on identical building block units in polymorphic co-crystals results in adjustable crystalline morphologies and variant photophysical properties (such as fluorescence wavelength, lifetimes and up-conversion luminescence). The optimized PLQY (63.1%) and lifetime (57.1 ns) are much higher than the pristine assembled units. Besides, two polymorphic co-crystals (DCA@TPFB-1 and AC@TPFB-2) present prominent fluorescence polarization and optical waveguide behaviors due to the highly regulated molecular orientation. Their high 1D luminescent anisotropy (0.652) and low optical waveguide loss (0.0079 dB/μm) outperform most of state-of-the-art low-dimensional molecular systems, and thus endow them great opportunities for photonic materials and devices. Therefore, this work not only confirms that polymorphic co-crystals can be an effective way to design new photofunctional materials for luminescence and photonic applications, but also discloses a deep understanding on the relationship between variant self-assembled fashions and tunable photofunctional properties of new TPFB-based molecular materials.