Highly luminescent liquid crystals by connecting 1,3,4-oxadiazole with thiazolo[5,4-d]thiazole units
| Autor: | Giliandro Farias, Cristian A. M. Salla, Ivan H. Bechtold, Hugo Gallardo, Arthur B.S. de Santos, Juliana Eccher, Ivani Malvestiti, Sergio F. Curcio, Alex M. Manfredi, Thiago Cazati, Eduardo H.L. Falcão, Edivandro Girotto, Eduard Westphal |
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| Rok vydání: | 2021 |
| Předmět: |
Materials science
Oxadiazole Mesophase 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Electronic Optical and Magnetic Materials chemistry.chemical_compound Crystallography chemistry Liquid crystal Excited state Materials Chemistry Alkoxy group Molecule Thermal stability Physical and Theoretical Chemistry 0210 nano-technology Thiazole Spectroscopy |
| Zdroj: | Journal of Molecular Liquids. 321:114887 |
| ISSN: | 0167-7322 |
| DOI: | 10.1016/j.molliq.2020.114887 |
| Popis: | The direct bonding between a thiazolo[5,4-d]thiazole and two 1,3,4-oxadiazole units allowed us to create a new and versatile rigid core for luminescent liquid crystal, which showed interesting and variable mesomorphic and photophysical properties. From the 5-bis(5-phenyl-1,3,4-oxadiazol-2-yl)thiazolo[5,4-d]thiazole new core, three molecules with different number of alkoxy chains were synthesized and had their properties correlated with the molecular structure. The molecule with two chains showed a smectic C mesophase, while the mesogens with four and six chains presented hexagonal columnar mesomorphism, which was confirmed by POM and XRD measurements. In addition, the molecule with six chains presented liquid crystalline behavior close to room temperature. In solution, the molecules presented strong photoluminescence ranging from blue to yellow, with quantum yields higher than 0.6. Excited state lifetimes allowed to correlate the fluorescence component associated to the different emitting species to the molecular organization in spin coated films. The molecular energy levels, together with thermal stability and possible charge carrier transport due to molecular packing, suggest that these molecules are promising for optoelectronic applications. Overall, this work contributes to the development of the use of thiazolo[5,4-d]thiazole in liquid crystals, demonstrating its great efficiency and versatility. |
| Databáze: | OpenAIRE |
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