Luminescent Polymorphic Co-crystals: A Promising Way to the Diversity of Molecular Assembly, Fluorescence Polarization, and Optical Waveguide

Abstract

The design of molecular optoelectronic materials based on fabricating polymorphs and/or co-crystals has received much recent attention in the fields of luminescence, sensors, nonlinear optics, and so on. If the advantages of the two crystal engineering strategies above were combined, the diversity of self-assembly fashions and the tuning of photofunctional performances would be largely extended. However, such multicomponent examples have still been 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 result in adjustable crystalline morphologies and variant photophysical properties (such as fluorescence wavelength, lifetimes, and up-conversion luminescence). The optimized photoluminescence quantum yield (63.1%) and lifetime (57.1 ns) are much higher than those of the pristine assembled units. In addition, 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 one-dimensional luminescence anisotropy (0.652) and low optical waveguide loss (0.0079 dB/μm) outperform most state-of-the-art low-dimensional molecular systems and thus endow them with great opportunities for photonic materials and devices. Therefore, this work not only confirms that constructing 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.

Wide range zero-thermal-quenching ultralong phosphorescence from zero-dimensional metal halide hybrids

“…olecular luminescent materials have attracted increasingly widespread attention due to their extensive applications in illumination resources, light-emitting diodes (LEDs), and biological imaging among many others [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . It is well known that the luminescence of molecular systems is usually sensitive to temperature, such that increasing temperature tends to provoke with intensification of molecular rotation and lattice vibration in chromophores, thereby facilitating the universal thermal-quenching (TQ) effect 21,22 .…”

Molecular Crystal Microcapsules: Formation of Sealed Hollow Chambers via Surfactant‐Mediated Growth

“…Third, the dye emission was completely unpolarized, consistent with freely diffusing molecules. This was in sharp contrast to the emission from the stationary NAPH‐TCNB crystal which showed a strong polarization dependence (Supporting Information, Figures S18,S19) as observed in other CT crystals [12] . In order to completely characterize the environment experienced by the encapsulated dye and assess whether it is suitable for optoelectronic applications, its fluorescence quantum yield and lifetime should be measured, which will be the subject of future work.…”

Manipulating Light‐Induced Dynamic Macro‐Movement and Static Photonic Properties within 1D Isostructural Hydrogen‐Bonded Molecular Cocrystals

“…To the best of our knowledge,t his polarization anisotropy value is higher than that of state-of-the-art 1D organic molecular crystals. [72] It is expected that this high anisotropy endows the NVP-THA co-crystal with high potential for use as apolarized luminescent material.…”