Synthesis And Second-order Optical Non-linearity Of DAMS-Mn₂P₂S₆ Materials By Ion Exchange Method

In the modern information times,non-linear optical(NLO) materials have been mostly applied in the high speed optical communications,optical information process and optical storage.Several chemical methodologies such as inorganic crystal,poled polymers and inorganic -organic hybrid materials have been developed in the recent years.In the latter,the NLO chromophores are incorporated into the inorganic matrix by one or more covalent bonds.These hybrid materials capitalize on the unique properties offered by the two components to generate novel materials with desired characteristics,therefore,they are considered as promising candidate for NLO device applications and have been the hot subject of NLO materials research.In this thesis,the basic theories of NLO and molecular design theory are briefly introduced,the research progress of second-order NLO materials are also reviewed. Research significance and recent progress of inorganic-organic hybrid NLO materials are summarized in detail,and the prospect is also discussed.Three main parts are involved in this study:the synthesis and difference of Mn2P2S6 particles by three methods(High Temperature Process,Room Temperature Solid-state method, Solution Approach) are performed in the first part.In the second part,the basic theories of NLO is briefly introduced,molecular design theory and recent progresses of inorganic-organic hybrid NLO materials are summarized in detail. 4-[4-(dimethylamino)-α-styryl]-1-methylpyridinium(DAMS) is synthesized in the part.In the third part,the Synthesis of Intercalated material DAMS-MnzPzS6 by Ion Exchange Method is introduced.The DAMS molecules are self-assembled in the layers of Mn₂P₂S₆ to form J-aggregates.The interlayer distance is widened after intercalation.Second-harmonic generation of DAMS/Mn₂P₂S₆ thin films is observed by Maker fringe measurement.It is shown from the XRD pattems,the layered material Mn₂P₂S₆ was obtained in room temperature by the solid-state method,and the crystalline form was nearly the same as that in the high temperature process.The chromophores was intensified by UV-visible spectroscopy,it was indicated that DAMS molecules self-assemble in the layers of Mn₂P₂S₆ to form J-aggregates.In Maker fringe measurements,the second-harmonic generation(SHG) was observed in DAMS-Mn₂P₂S₆ powder which obtained by ion exchange method.