Synthesis, Characterization Of CuBr₂-based Organic-inorganic Layered Perovskite Hybrids Materials

Organic-inorganic layered perovskite-type hybrids give the possibilities of integrating useful characteristics organic and inorganic compounds on a molecular level. However, the properties of hybrids in present can not satisfy the requiring of appliances. According to the reports, electrical properties can be improved by increasing perovskite layer thickness, but the structure forming and controlling of which is quite difficult. So this article researched on the synthesis of monolayered and bilayered hybrids to explore the law of the structure forming.This dissertation focuses on the synthesis and the structures of the hybrids with chemical formula (C4H9NH3)2(CH3NH3)n-1CunBr3n+1(n=1,2) in theory, which is expected to have CuBr2-based monolayered and dilayered perovskite-type structure hybrids. The hybrids were synthesized through solution method and solid method, in which the synthesis processes were researched systematically.When monolayered hybrids were synthesized via solution method, the kinds of solvents did not affect the products structure. When the bilayered hybrids in theory were synthesized, the products under different solvents had the same structure (but the products in HBr also had the phase of monolayered structure). The ratio and temperature could affect crystallization of products rather than the pattern positions of XRD. The optimal condition:ethanol as solvent, under 60℃with the ratio of 2:2.5:2. The monolayered hybrids were also synthesized successfully via solid method. When the bilayered hybrids in theory were synthesized, the ratio could affect the completion of reaction. The temperature and time could affect crystallization of products rather than the pattern positions of XRD. The optimal condition:under 80℃heated 3 days with the ratio of 2:2.5:2.The structures, chemical components and properties of the acquired products at room temperature were characterized and analyzed by XRD, Element analysis, SEM, FTIR, TG-DSC and Spectrum analysis. The results show that the structure of monolayered product accords with the anticipated structure. But the prospective product with bilayered structure cannot be acquired, although its crystal structure is oriented obviously. According to the data analysis of various characterization of structure and properties, the structure of the acquired product can be a monolayered structure which refers that the cation of methylamine salt and butylamine salt both enter the space between the inorganic layers:The results of Element analysis are tally with the elements percentage of theoretic chemical formula (C4H9NH3) (CH3NH3) CuBr4 which is reasoned out. In FTIR, the phenomena of vibrancy absorbance peaks related to-CH2-are weakened obviously show the content of butylamine is decreased, which supports the conjecture of structure above. The results of TG-DSC show the breaking up temperature of the product with new structure is lower than that of monolayered product, which is consistent with the descending trend of breaking up temperature because of the weaker acting force between organic components, when the cation of methylamine exists. The results of Spectrum analysis show that the positions of the absorption peaks produced by the products with two kinds of structures hardly shift. The positions of the luminescence peaks are also the same basically, which are at 458nm and 457nm respectively. These indicate the consistency of the structure of the two products'inorganic layer, and show that the perovskite layer of the new product is monolayer.