Synthesis And Properties Of Organic-inorganic Hybrid Perovskites Based On Halogenated Amine And Lead,Tin Metals

Since it discovered in the late 19th century,organic-inorganic hbrid perovskites have shown great potential in electronic,optical,and new energy due to their unique structural characteristics,and represent an important contemporary research goal.Organic and inorganic perovskites are diverse in structure,and the inorganic framework exhibits good performance in semiconductor material and optoelectronic material,and the embedded organic ammonium cations are tend to occure orderly-disorderly phase transition under high temperature or high pressure,and usually also cause the change of molecular dipole moment,showing good characteristics of phase transition,dielectric and even ferroelectric materials.At present,3D lead and tin(?)-based hybrid perovskites have been widely studied in solar photovoltaic cells,and there are less studies on low-dimensional lead-based perovskites and tin(?)-based perovskites,so it is necessary to study it further.Based on these,nine novel lead-based and tin(?)-based organic-inorganic hybrid perovskites were synthesized in this papar.In order to avoid the blindness and randomness of the process,the original non-polar phase transition structure was modified by fluorination and the intermolecular halogen-halogention between molecules was incressed,that is,replacing the H sites on the benzene ring of n-methyl benzylamine with strong electronegative fluorine atoms,the fluoro-organic amine 3-Fluoro-N-methyl benzylamine was obtained.And using it as the organic ligand,three compounds 1?3 were synthesized.On the basis of fluorine substitution,we tried to synthesize compounds 4?7 with 3-Chloro-N-methylbenzylamine as the organic ligand by regulating the halogen of benzylamine.Continue to increase the weight of substituents of organic amine halogen and synthesize two organic-inorganic hybrid perovskite compounds 8,9 with 3-Bromo-N-methylaniline ligand.It was found that compounds 1,2,3 and 8 exhibited obvious reversible phase transition characteristics under the action of temperature,in which compounds 2,3 and 8 exhibited obvious dielectric anomalies near the phase transition points.It fully conforms to the basic characteristics of phase change materials.In addition,the optical band gap value of the compounds was estimated according to the uv-visible absorption spectra of compounds 1?9,and the results showed that the ligand compounds of SnCl4 were all wideband band gap compounds,while the other compounds were all medium band gap compounds.