Synthesis And Study Of Polycyclic Liquid Crystal And Fluorescent Dichroic Liquid Crystal Dyes

Three series of fluorescence dichroic liquid crystal dye have been synthesised by designing acenaphthene quinine, naphthalene anhydride, benzanthrone derivatives. Some of them have wide liquid crystal phase and bright fluorescence. The application of the "gest-host" mode in liquid crystal display can not only improve the low utilization rate of the traditional LCD, but also have the advantages of high brightness, bright color, and so on. All the new molecules are tested for spectral properties, including UV-Vis, fluorescence and polarization spectra. The liquid crystal molecules have been tested for threshold voltage. All the new molecules are tested nuclear magnetic resonance spectroscopy and mass spectrometry. The properties of all the synthesized molecules are studied and analyzed.W series of acenaphthene quinone derivatives of the liquid crystal dye emissioned bright blue fluorescence and yellow-green fluorescence, which W3, W5 and W6 have fluorescence quantum yield as high as more than 0.80 in dichloromethane; absorption maximum wavelength of is up to 445nm, emission wavelength maximum is up to 563; molar extinction coefficients are above 104. The maximum absorption order parameter is 0.68; the maximum fluorescence order parameter is up to 0.57 when dissolved in the positive liquid crystal E7. The mixture of liquid crystal dyes and E7 does not affect the positive and negative of the refractive index of E7.The absorption wavelength of Z series of naphthalimide fluorescent liquid crystal dye are at around 390 nm and emission wavelength are at around 500 nm. Bright yellow-green fluorescence was observed and the maximum fluorescence quantum yield reaches up to 0.88. Stokes shift are more than 100 nm. The maximum absorption order parameter of Z7, SA is 0.69 and SF is between 0.41-0.63 in liquid crystal E7, which meets the requirements for use. In the negative liquid crystal BHR28000-300, the order parameter of Z1 with the applied voltage of 10 V is up to 0.84, and all the order parameter are higher than 0.45. DSC test showed that Z1, Z2 and Z3 have wide phase transition temperature, and polarized light microscopy shows that all coupounds have a broad nematic phase, reaching more than 60?. The mixture of liquid crystal and Z can adjust the refractive index and liquid crystal phase. The photoelectric properties of the tested compounds showed that the threshold voltage could be improved. Compound Z4 and E7 can reduce the threshold voltage of the positive liquid crystal E7 by 0.022 V, and the response time was added 0.003 s.The maximum absorption wavelength of the F series benzanthrone fluorescence dichroic liquid crystal dye liquid dye are in the visible region of the spectrum, emission wavelength are at around 500 nm. The bright yellow-green fluorescence was observed in dichloromethane. Molar extinction coefficients are more than 104 in dichloromethane and different solvent. Half peak width is between 60-80 nm which can be conducive to the realization of color display. The maximum of F series of fluorescence quantum yield is up to a maximum of 0.65 in dichloromethane. In liquid crystal E7, Sa is up to 0.65, and SA is up to 0.85 in negative liquid crystal BHR28000-300. The photoelectric properties of the tested compounds showed that the threshold voltage could be improved. Compound F2 and E7 can reduce the threshold voltage of the positive liquid crystal E7 by 0.210 V, and the response time was added 0.002s.