TY - JOUR
T1 - Mesomorphic organization and thermochromic luminescence of dicyanodistyrylbenzene-based phasmidic molecular disks
T2 - Uniaxially aligned hexagonal columnar liquid crystals at room temperature with enhanced fluorescence emission and semiconductivity
AU - Yoon, Seong Jun
AU - Kim, Jong H.
AU - Kim, Kil Suk
AU - Chung, Jong Won
AU - Heinrich, Benoît
AU - Mathevet, Fabrice
AU - Kim, Pyosang
AU - Donnio, Bertrand
AU - Attias, André Jean
AU - Kim, Dongho
AU - Park, Soo Young
PY - 2012/1/11
Y1 - 2012/1/11
N2 - A new dicyanodistyrylbenzene-based phasmidic molecule, (2Z,2′Z)-2, 2′-(1,4-phenylene)bis(3-(3,4,5-tris(dodecyloxy)phenyl)acrylonitrile), GDCS, is reported, which forms a hexagonal columnar liquid crystal (LC) phase at room temperature (RT). GDCS molecules self-assemble into supramolecular disks consisting of a pair of molecules in a side-by-side disposition assisted by secondary bonding interactions of the lateral polar cyano group, which, in turn, constitute the hexagonal columnar LC structure. GDCS shows very intense green/yellow fluorescence in liquid/solid crystalline states, respectively, in contrast to the total absence of fluorescence emission in the isotropic melt state according to the characteristic aggregation-induced enhanced emission (AIEE) behavior. The AIEE and two-color luminescence thermochromism of GDCS are attributed to the peculiar intra- and intermolecular interactions of dipolar cyanostilbene units. It was found that the intramolecular planarization and restricted molecular motion associated with a specific stacking situation in the liquid/solid crystalline phases are responsible for the AIEE phenomenon. The origin of the two-color luminescence was elucidated to be due to the interdisk stacking alteration in a given column driven by the specific local dipole coupling between molecular disks. These stacking changes, in turn, resulted in the different degree of excited-state dimeric coupling to give different emission colors. To understand the complicated photophysical properties of GDCS, temperature-dependent steady-state and time-resolved PL measurements have been comprehensively carried out. Uniaxially aligned and highly fluorescent LC and crystalline microwires of GDCS are fabricated by using the micromolding in capillaries (MIMIC) method. Significantly enhanced electrical conductivity (0.8 ×10 -5 S·cm -1/3.9 ×10 -5 S·cm -1) of the aligned LC/crystal microwires were obtained over that of multi-domain LC sample, because of the almost perfect shear alignment of the LC material achieved in the MIMIC mold.
AB - A new dicyanodistyrylbenzene-based phasmidic molecule, (2Z,2′Z)-2, 2′-(1,4-phenylene)bis(3-(3,4,5-tris(dodecyloxy)phenyl)acrylonitrile), GDCS, is reported, which forms a hexagonal columnar liquid crystal (LC) phase at room temperature (RT). GDCS molecules self-assemble into supramolecular disks consisting of a pair of molecules in a side-by-side disposition assisted by secondary bonding interactions of the lateral polar cyano group, which, in turn, constitute the hexagonal columnar LC structure. GDCS shows very intense green/yellow fluorescence in liquid/solid crystalline states, respectively, in contrast to the total absence of fluorescence emission in the isotropic melt state according to the characteristic aggregation-induced enhanced emission (AIEE) behavior. The AIEE and two-color luminescence thermochromism of GDCS are attributed to the peculiar intra- and intermolecular interactions of dipolar cyanostilbene units. It was found that the intramolecular planarization and restricted molecular motion associated with a specific stacking situation in the liquid/solid crystalline phases are responsible for the AIEE phenomenon. The origin of the two-color luminescence was elucidated to be due to the interdisk stacking alteration in a given column driven by the specific local dipole coupling between molecular disks. These stacking changes, in turn, resulted in the different degree of excited-state dimeric coupling to give different emission colors. To understand the complicated photophysical properties of GDCS, temperature-dependent steady-state and time-resolved PL measurements have been comprehensively carried out. Uniaxially aligned and highly fluorescent LC and crystalline microwires of GDCS are fabricated by using the micromolding in capillaries (MIMIC) method. Significantly enhanced electrical conductivity (0.8 ×10 -5 S·cm -1/3.9 ×10 -5 S·cm -1) of the aligned LC/crystal microwires were obtained over that of multi-domain LC sample, because of the almost perfect shear alignment of the LC material achieved in the MIMIC mold.
KW - electro-optical materials
KW - liquid crystals
KW - structure-property relationships
UR - http://www.scopus.com/inward/record.url?scp=84855319446&partnerID=8YFLogxK
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U2 - 10.1002/adfm.201101818
DO - 10.1002/adfm.201101818
M3 - Article
AN - SCOPUS:84855319446
SN - 1616-301X
VL - 22
SP - 61
EP - 69
JO - Advanced Functional Materials
JF - Advanced Functional Materials
IS - 1
ER -