Synthesis,Structure And Properties Of Organic-inorganic (?/?A)Hybrid Perovskites

With the continuous development of science and technology,industrial intelligence and integration have put forward higher requirements for the application of materials,and multifunctional materials with excellent performance have also emerged.Hybrid perovskite materials become an important new type of functional materials,and because of their excellent characteristics in many aspects such as sound,light,electricity,and magnetism,make it a hot spot of current research.In this paper,seven hybrid perovskite compounds were synthesized based on the theoretical basis of related literatures,and passed dielectric testing,X-ray single crystal diffraction,differential scanning calorimetry(DSC),ultraviolet absorption,fluorescence,nonlinear optical effects(SHG)and other testing and analysis methods to research the structures and properties of them.The main contents of this paper are as follows:1.Three two-dimensional organic-inorganic hybrid perovskite compounds(1-3)were discovered and synthesized.The temperature-change single crystal X-ray diffraction tests were used to measure the high-temperature phase and the low-temperature phase structures and revealed the phase transition mechanism of the compounds.Results indicated that through the substitution of Cl,Br,I,the phase transition temperatures and crystal structures can be well adjusted.At the same time,with the replacement of the halogen atoms Cl,Br,I,their optical band gap,fluorescence performance and dielectric performance also showed great good characteristics,meanwhile,their microscopic mechanism was clarified by first-principles simulation.2.Two cases of hybrid compounds(4-5)were synthesized by using antimony trichloride as the inorganic skeleton basis and selecting tetrahydrothiazole and thiomorpholine as organic ligands,respectively.Dielectric,DSC,variable temperature single crystal,powder X-ray diffraction(PXRD)and thermogravimetry(TG)analysis were used to verify the phase transition,crystal structure,purity and stability,etc.The results showed that both compounds have reversible structural phase transitions,and the higher dielectric constant changes of the compounds provide more possibilities for their applications.3.Choose two flexible organic amines,trichloropropylamine hydrochloride and tribromopropylamine hydrobromide as ligands,and stannous chloride and leadbromide were used as inorganic frameworks to synthesize two cases of hybrid perovskite compounds(6-7).Dielectric tests revealed that the dielectric behavior of the two compounds is found to be abnormal with the change of temperature,thereinto,the dielectric constant of compound 6 changed by twice,while the dielectric of compound 7 has a frequency dependent relaxation behavior.UV absorption spectroscopy showed that both compounds have good semiconductor properties.Since compound 7 was located in a non-centrosymmetrical space group,non-linear optical measurement of it exhibited a strong SHG response.The above tests showed that compounds could be used as potential multifunctional dielectric switching materials.