Preparation And Properties Of Organic Second-order Nonlinear Optical Crystals Based On Stilbene Structure

The main work of this paper is to select a special conjugate bridge in order to design the organic optical chromophore molecules with second order nonlinear optical effect.Based on the two-level model and charge transfer theories,the research focuses on organic compounds with D-?-A structure.The most basic factor that determines the nonlinear optical properties of chromophore is the intramolecular charge transfer efficiency,which has different delocalization efficiency for different conjugated bridges,and stilbene is one of the conjugated systems with the highest electron delocalization efficiency.Based on stilbene,both ends of the ?-conjugate bridge are adding different donor and receptor groups,or the aromatic rings with different densities are introduced into the conjugate bridge,which can strengthen the intramolecular charge transfer efficiency,and although the increase of conjugated length is advantageous to the electronic transfer of a wide range,but may also make the light through the largest cutoff wavelength redshift.In this paper,through the introduction of several functional groups(methyl,methoxy,dimethyl amine,etc.)or aromatic ring to change the structure of organic compound,so that it has strong SHG signal and high transmittance in visible and near-infrared regions,and we grow the four crystal materials(DADMQ,DAMQ,DAMC,DMMC)with strong second order nonlinear optical effects.In addition,the growth characteristics,lattice structure and thermal,electrical and optical characteristics of the four kinds of crystal materials are measured.The results show that they have good thermal stability,normal dielectric behavior and better light transmittance,which makes them have great potential to be used in photoelectric equipment.