Design And Synthesis Of High Electro-optic Active Chromophore Molecules

Since the beginning of the 21st century,information technology has been in a period of rapid development.Among them,optical fiber communication,mobile communication,satellite communication and other technologies are developing rapidly in the global scope.The performance of traditional inorganic second-order nonlinear optical materials will soon be unable to meet the current communication office.Needed,organic second-order nonlinear optical materials have more nonlinear optical effects,ultra-fast response speed,higher optical damage threshold,good processability and lower material cost,so they are more and more s concern.As an important part of organic second-order nonlinear optical materials,chromophores have become one of the important research objects of scientists.In order to meet the needs of use,there are still two key issues that need to be solved urgently:one is to design and synthesize organic second-order nonlinear optical chromophores with higher molecular first-order super-resolution and good optical transparency.The second is the efficient conversion of small molecule nonlinear optical activity into electro-optic activity of macroscopic materials.Six kinds of Y-type,V-type second-order nonlinear optical chromophore molecules were designed and synthesized,and their structures were determined by NMR.The optical and thermal stability were characterized by UV-Vis spectroscopy,scanning differential calorimetry and thermogravimetric analysis.The results show that the T_d of these six chromophores are all greater than 250°C,and both have good thermal stability.The UV-visible absorption spectrum of the chromophore showed that the chromophore Y1 with Y-type double donor had a larger maximum absorption wavelength than the V-type chromophore,indicating that Y1 has a greater degree of intramolecular charge transfer.The chromophore is doped into the polycarbonate,and the prepared host-guest doped film has a larger doping concentration,and the Y-type molecule has a larger electro-optic coefficient relative to the V-type molecule,and r₃₃ is 25 pm V^-1,indicating that the Y-type molecule has a larger electron donating ability,thereby obtaining greater electro-optic activity.Six organic second-order nonlinear optical chromophore molecules containing benzothiadiazole co-receptors were designed and synthesized,and their structures were characterized by NMR and MS.The thermal stability and optical properties were characterized.The DSC and TGA results show that the T_d of the six chromophores are all greater than 250°C,indicating excellent thermal stability.The UV-visible absorption spectrum of the chromophore showed that the intramolecular charge transfer of the chromophore with benzothiadiazole as the conjugated bridge was significantly enhanced relative to the reference chromophore r1.The chromophore is doped into the polycarbonate,and the prepared host-guest doped film,the host-guest electro-optic film 5a/PC and 5b/PC have a large r₃₃ value,67 and 45 pm V^-1.Higher than the reference chromophore FTC containing thiophene as a conjugated bridge.