High-contrast electrically switchable light-emitting liquid crystal displays based on α-cyanostilbenic derivative

Lu, Hongbo; Xu, Chao; Li, Zhiyuan; Xia, Guo; Jing, Shuaicheng; Bai, Xiaojing; Yang, Jiaxiang; Qiu, Longzhen; Ding, Yunsheng

doi:10.1080/02678292.2017.1292007

Cited by 12 publications

(2 citation statements)

References 29 publications

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“…Dye solubility in the LC host matrix is one of the main limits. For this reason, the aim of LC display technology and temperature-responsive PL modulator/switch probes is a soluble fluorophore, that does not show ACQ effects at the required concentrations [62,63]. In our experiments, the two dyes were dissolved at 25 °C in a commercially available nematic polymer (QYPDLC-102, T i = 113 °C) at 1% by weight even if their solubility enables to increase concentration up to 10 times.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Bulky Substituents on Two π-Conjugated Mesogenic Fluorophores. Their Organic Polymers and Zinc-Bridged Luminescent Networks

et al. 2019

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From a dicyano-phenylenevinylene (PV) and an azobenzene (AB) skeleton, two new symmetrical salen dyes were obtained. Terminal bulky substituents able to reduce intermolecular interactions and flexible tails to guarantee solubility were added to the fluorogenic cores. Photochemical performances were investigated on the small molecules in solution, as neat crystals and as dopants in polymeric matrixes. High fluorescence quantum yield in the orange-red region was observed for the brightest emissive films (88% yield). The spectra of absorption and fluorescence were predicted by Density Functional Theory (DFT) calculations. The predicted energy levels of the frontier orbitals are in good agreement with voltammetry and molecular spectroscopy measures. Employing the two dyes as dopants of a nematic polymer led to remarkable orange or yellow luminescence, which dramatically decreases in on-off switch mode after liquid crystal (LC) order was lost. The fluorogenic cores were also embedded in organic polymers and self-assembly zinc coordination networks to transfer the emission properties to a macro-system. The final polymers emit from red to yellow both in solution and in the solid state and their photoluminescence (PL) performance are, in some cases, enhanced when compared to the fluorogenic cores.

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Section: Resultsmentioning

confidence: 99%

The Effect of Bulky Substituents on Two π-Conjugated Mesogenic Fluorophores. Their Organic Polymers and Zinc-Bridged Luminescent Networks

et al. 2019

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“…The luminescence mechanism of ESIPT chromophores contains a four-level photocycle with the presence of the proton donor and acceptor structures. , Because of this mechanism, ESIPT molecules show a characteristic large Stokes shift, which minimizes the self-absorption and thus is beneficial for the application in organic photonics and bioimaging fields. − For instance, ESIPT chromophores have been employed for laser dyes, UV stabilizers, solar concentrators, organic radiation scintillators, fluorescent bioimaging probes, and so on. Light-emitting liquid-crystal displays (LE-LCDs) − have received great attention as energy-efficient alternatives to conventional LCDs since polarized light emission from LC molecules enables one of the polarizers to be removed. One convenient approach to obtain LE-LCDs is doping of luminescent molecules in a nematic LC host. − The miscibility (solubility and compatibility) between host and guest (dopant) molecules , is the primary issue in the system.…”

Section: Introductionmentioning

confidence: 99%

Highly Miscible Hybrid Liquid-Crystal Systems Containing Fluorescent Excited-State Intramolecular Proton Transfer Molecules

et al. 2019

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Doping of luminescent molecules in a nematic liquid-crystal (LC) host is a convenient approach to develop light-emitting LC displays that would be a promising alternative to conventional LC displays. The requirements for the luminescent guest molecules include high miscibility in the host LC, high-order parameters in the host LC media to show anisotropic luminescence, lack of self-absorption, transparency in the visible region, and a large photoluminescence quantum yield independent of its concentration. To address these issues, here, we newly synthesize a highly miscible and fluorescent excited-state intramolecular proton transfer molecule, C 4 -CC-HBT, based on 2-(2-hydroxyphenyl)benzothiazole (HBT). This compound is highly miscible in a conventional room-temperature nematic LC 4-pentyl-4′-cyano biphenyl (5CB) up to 14 wt % (∼12 mol %) and exhibits a large photoluminescence quantum yield of ΦFL = 0.32 in the 5CB host, both of which were achieved by the introduction of an alkynyl group into the HBT core. C 4 -CC-HBT possesses a high-order parameter of S = 0.46 in 5CB, and the C 4 -CC-HBT/5CB mixtures show anisotropic fluorescence whose intensity is controlled by the applied electric field. A patterned image is demonstrated, which is not visible under an ambient environment but is readable upon UV illumination, relying on the orientational differences of ordered C 4 -CC-HBT molecules.

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Fluorescent Photochromic α‐Cyanodiarylethene Molecular Switches: An Emerging and Promising Class of Functional Diarylethene

Lin

Gutiérrez-Cuevas

Zhang

et al. 2020

Adv Funct Materials

157

102

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Fluorescent photochromic molecules that exhibit distinct light‐triggered changes in their emission colors are highly desirable for the fabrication of smart soft materials and advanced photonic devices. α‐Cyanodiarylethenes, that is, α‐cyano‐functionalized diarylethenes, as alternative “non‐azo” Z/E photochromic molecular switches, are popular choices due to their unique characteristics such as their aggregation‐induced emission or aggregation‐induced‐enhanced emission behavior in their self‐assembled states, and visible changes in fluorescence colors during Z/E photoisomerization. In recent years, the development of fluorescent photochromic α‐cyanodiarylethene‐based compounds including α‐cyanostilbenes, dicyanodistyrylbenzenes, and diaryldicyanoethenes, has mainly focused on molecular design, photochemical and photophysical behavior in solution, and smart soft matter technologies. In this review, recent significant achievements in light‐responsive systems based on the Z/E photoisomerization of fluorescent photochromic α‐cyanodiarylethene switches that span the range from liquid crystals to gels and finally to self‐assembled nanostructures, are highlighted. The smart soft materials constructed from α‐cyanodiarylethene molecular switches find use in a plethora of areas, including display, sensing, encrypting, actuating, and biomedical imaging applications, among others. The review concludes with a brief perspective on some major challenges and opportunities for the future development of light‐responsive smart soft photonic materials.

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High-contrast electrically switchable light-emitting liquid crystal displays based on α-cyanostilbenic derivative

Cited by 12 publications

References 29 publications

The Effect of Bulky Substituents on Two π-Conjugated Mesogenic Fluorophores. Their Organic Polymers and Zinc-Bridged Luminescent Networks

The Effect of Bulky Substituents on Two π-Conjugated Mesogenic Fluorophores. Their Organic Polymers and Zinc-Bridged Luminescent Networks

Highly Miscible Hybrid Liquid-Crystal Systems Containing Fluorescent Excited-State Intramolecular Proton Transfer Molecules

Fluorescent Photochromic α‐Cyanodiarylethene Molecular Switches: An Emerging and Promising Class of Functional Diarylethene

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