Multi‐Color Photoluminescence Based on Mechanically and Thermally Induced Liquid‐Crystalline Phase Transitions of a Hydrogen‐Bonded Benzodithiophene Derivative
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Media type:
E-Article
Title:
Multi‐Color Photoluminescence Based on Mechanically and Thermally Induced Liquid‐Crystalline Phase Transitions of a Hydrogen‐Bonded Benzodithiophene Derivative
Contributor:
Seki, Atsushi;
Yoshio, Masafumi
Published:
Wiley, 2020
Published in:
ChemPhysChem, 21 (2020) 4, Seite 328-334
Description:
<jats:title>Abstract</jats:title><jats:p>Controlling assembled structures of π‐conjugated liquid‐crystalline molecules is of great interest in the development of stimuli‐responsive luminescent materials due to their molecular motility in the ordered states. Herein, we describe a mechanoresponsive hydrogen‐bonded benzodithiophene liquid‐crystalline molecule that exhibits a tricolor photoluminescence switching at ambient temperature. The compound shows a shear‐induced phase transition from a rectangular columnar to a metastable optically anisotropic mesophase, which is accompanied by the luminescent color change from yellow to sky‐blue. The metastable mesophase exhibits a time‐responsive transformation to another metastable mesophase showing a blue‐green emission through isothermal aging at room temperature. The luminescent color of aged sample reverts back to the initial yellow color by thermal annealing at 150 °C. These dynamic structural changes accompanied by the emission color changes are governed by distinct π‐stacking modes and hydrogen‐bonded patterns. The shear‐induced luminescent color change from yellow to blue is found to occur above the shear strain of 390 % at which the shear stress is 2.4×10<jats:sup>5</jats:sup> Pa as determined from dynamic viscoelastic measurements.</jats:p>