Optical Waveguide and Photoluminescent Polarization in Organic Cocrystal Polymorphs

Abstract

Organic cocrystals whose unique polymorphic feature can provide a feasible way to investigate and understand the relationship between luminescence properties and aggregate structures have attracted increasing attention in the area of organic optoelectronics. Herein, we prepare polymorphic cocrystals (C1, C2) by using 9,10-bis­((E)-2-(pyridin-3-yl)­vinyl)­anthracene (BP3VA) as chromophore and 1,3,5-trifluoro-2,4,6-triiodobenzene (FIB) as conformer. Both C1 and C2 stack with segregated stacking form, but different intermolecular interactions promote the formation of sheet cocrystals C1 and needle cocrystals C2. C1 exhibits anisotropic optical waveguide property and photoluminescent polarization, while C2 only exhibits the quasi-one-dimensional optical waveguide property. The different optical properties originate from the varieties of molecular packing modes and directions of the optical transition dipole in the two polymorphic cocrystals, which can be clarified through the structure analysis and theoretical calculation. The study can provide a deep understanding of the structure–property relationship of cocrystals and benefit the rational design of novel functional materials.

Multicomponent Molecular Assembly of Fluorescent Organic Semiconductors Beyond Three Compounds

“…[ 1–5 ] Photonic and electronic performances of crystalline organic assemblies have been demonstrated to be dimension and/or shape dependent. [ 6–21 ] For instance, 1D rod‐like crystals tend to act as Fabry–Pérot (F–P) resonance cavities, [ 6–12 ] while 2D platelet‐like crystals act as whispering gallery mode (WGM) cavities. [ 13–15 ] Not only that, 1D and 2D assemblies have also shown distinctly different optical waveguide behaviors.…”

“…been demonstrated to be dimension and/ or shape dependent. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] For instance, 1D rod-like crystals tend to act as Fabry-Pérot (F-P) resonance cavities, [6][7][8][9][10][11][12] while 2D platelet-like crystals act as whispering gallery mode (WGM) cavities. [13][14][15] Not only that, 1D and 2D assemblies have also shown distinctly different optical waveguide behaviors.…”

“…[13][14][15] Not only that, 1D and 2D assemblies have also shown distinctly different optical waveguide behaviors. [16][17][18][19][20] Even if in the same dimension, square and rhombic microsheets/microplates generally exhibit symmetric and asymmetric photon propagation characters, respectively. [20,21] Apart from the considerations of molecular structures and intermolecular interactions, it has been well demonstrated that growth kinetics would also be of crucial importance for the modulation of dimensions, shapes, and polymorphisms of single-component π-stacked organic assemblies.…”

Tuning p-type to n-type semiconductor nature by charge transfer cocrystallization: effect of transfer integral vs. reorganization energy

“…4 Organic charge transfer cocrystals comprising π-donor (D) and π-acceptor (A) moieties have attracted wide attention owing to their usage as novel semiconductor materials, including ambi-polar field effect transistors (FETs), 5 active optical waveguides, 6 a solid state semiconductor lasers, 6 b photovoltaic devices 7 and organic light emitting transistors (OLETs). 8 Meanwhile, their widespread use in organic FETs with high ambi-polar/electron carrier nature is particularly remarkable in this regard. 5…”

Enhanced luminescence of single-benzene fluorescent molecules through halogen bond cocrystals

“…1 In particular, as one of the most cutting-edge research topics, luminescent organic materials have attracted strong interest due to their potential applications in the fields of organic light-emitting diodes (OLEDS), biological imaging, organic solid-state lasers, chemical sensors, etc. [2][3][4][5][6][7] Meanwhile, high-emission efficiency in the solid state is an extremely important prerequisite for the applications of such desired devices with superior performance. 8 Common organic fluorescent scaffolds are mainly based on planar rigid extended π-conjugate systems or a push-pull system with a strong donor-π-acceptor framework.…”