Growth And Properties Of Ionic Organic Nonlinear Optical Crystal DOST And Its Derivatives

Organic nonlinear optical material is an important part of nonlinear optical materials.It has a series of advantages that inorganic nonlinear materials cannot surpass,such as high nonlinear optical coefficient,low dielectric constant,fast optical response,high design possibility and so on.These materials can be widely used in optical information processing,optical data storage,optical frequency conversion and other fields.In this paper,two new ionic organic nonlinear optical crystal materials,dost and doqt,are designed by different crystal design methods.The raw materials for crystal growth were synthesized by organic condensation reaction.The crystal growth was carried out by evaporation method and cooling method.The structure and properties of the raw materials were analyzed comprehensively.Through single crystal XRD analysis,it is confirmed that dost crystal is a kind of material with non-centrosymmetric structure.The first hyperpolarizability of DOST crystal is calculated by single crystal structure data?_max,high diagonal order parameter cos³?_p.HOMO-LUMO energy level,molecular electrostatic potential surface and dipole moment;The growth mechanism and defect distribution of single crystal were studied by means of particle cyclotron accelerated X-ray synchrotron radiation and chemical etching;The absorption coefficient and transmittance of the crystal were measured by UV-Vis-NIR absorption spectrum,and a series of optical parameters such as refractive index and reflectivity were calculated;The electron transition and luminescent properties in the crystal were studied by photoluminescence analysis.The dielectric and ferroelectric properties of the crystal were measured and analyzed;The melting point and thermal stability of the crystal were confirmed by TG/DSC.As a phase matched nonlinear crystal,DOST crystal has a very high SHG efficiency,which is about 4 times of DAST and 21times of KDP at the same particle size.DOQT crystal was characterized by SHG test,UV-Vis-NIR absorption test,photoluminescence test,dielectric test and TG/DSC test.Through the comparative analysis of DOQT and DOST,we found a strong electron donor functional group which can greatly improve the crystal solubility.