Synthesis And Properties Of Organic-inorganic Hybrid Halides And Chalcogenides

Main group metal halides and sulfides have been widely studied due to their abundant topological structures and excellent properties(such as optical,fluorescence,catalysis and ion exchange,etc.),for example,the main group metal halides have been used in the perovskite photoelectric materials,and porous main group metal chalcogenides have been used to remove heavy metal ions.However,in the research of organic-inorganic hybrid halides,organic ingredients were often used as structure-directing agents,but how to use the functionality of the conjugated organic compounds,which was combined with inorganic halides has not been explored yet.In addition,although a lot of multiporous metal chalcogenides were reported,the control of hole size still needs to be researched.In this thesis,tin halides with conjugated organic ligands are prepared.The relations between the structures and optical or photosensitive properties are studied and its potential application in the dye sensitized photoelectric field is discussed.In addition,metal chalcogenides with 3-D framework structures and tunable hole sizes are prepared,and their crystal structures,photosensitive and ion exchange properties are studied.The main research contents of thesis are as follows:1.The introduction mainly includes two parts:the research and application status of lead,tin halides and germanium,tin chalcogenides.The first part summarizes the synthesis and development of organic-inorganic halides,especially in the application of photoelectric materials.The second part mainly generalizes germanium,tin chalcogenides with polyamine as organic cations and Cu as a transition metal,or surfactants/ionic liquids as organic components.2.A series of organic-inorganic hybrid tin halides formulated as Sn(phen)XmYn,XmYn=C14(1),Br4(2),14(3),Cl2I2(4)and Br2I2(5),were designed and prepared to study main group metal halides as photosensitive dyes.The colors of compounds are tunable with the change of mole ratio of the halides due to the ligand to ligand charge-transfer(LLCT).Intense visible-range absorption can be obtained by increasing the mole ratio of iodine and intense ultraviolet fluorescence emission can be obtained by increasing the mole ratio of chlorine.DFT calculations suggest that the LLCT occurs from electron-rich halide ion to?*orbit of phen.The iodide materials have narrow energy gap and suitable energy level of the excited state for exciton transfer to TiO2 semiconductor.Photocurrent responses experiments using the compounds treated TiO2 electrodes showed that upon irradiation stable photocurrent generated and Sn(phen)I4 has the best photosensitive behavior.3.Three ternary and 3-D chalcogenides with different hole sizes,(H2dap)2CusGe6S18(6),(H2en)2Cu8Ge5S16(7)and(H2en)2Cu8Ge3Sn2S16(8),were prepared,in which chelating amine en and 1,2-propanediamine are as template agents and 14 metals Sn and Ge are as the main group metals.Single crystal analysis found that the secondary building unit of the 3-D framework of these compounds is a same[Cu8S12]16-cluster which is extended in three directions into a six-connected 3-D framework via two types connectivity:the dimeric[Ge2S6]4+/[Sn2S2]4+ units or tetrahedral[GeS4]4+ units.Uv-vis spectra characterization found that the band gaps of the three compounds are between 2-2.5eV and they are potential semiconductor materials.Meanwhile,their solid photocurrent responses are on the 10-7 orders of magnitude,and ion exchange experiments show that these compounds can exchange with Cs+ and Cd2+ and Pb2+,et al.These results indicate that 6-8 have potential applications in the field of photoelectric and wastewater treatment.