| In recent years layered organic-inorganic perovskite-type materials have attracted much attention due to their unique structure and electronic properties, as well as their excellent film-processability. In the article, thin films of organic-inorganic hybrid compounds (RNH3)2PbX4 (R=CnH2n+1 n=1,2,4,6,8,10; C6H5CH2; X=Cl,Br,I) and(RNH3)2CuCl4 (R=C6H13; C6H5CH2) were prepared by the spin-coating method. The techniques of thin-film deposition, crystal structures and optical properties of the compounds were researched.The crystal structure of the (CnH2n+1NH3)2PbX4(n=2,4,6,8,10) and(RNH3)2CuCl4 powders and films were characterized by X-ray diffraction(XRD), and it was confirmed that both powders and films taking on preferable layered crystal structures. Compared to powders, only the diffraction patterns from the (0 0 2l) plane were observed in the spin-coated films, indicating that the films were highly oriented, with the plane of the perovskite sheets (0 0 2l) parallel to the substrate surface. This corresponded to the results of AFM and from it we could see clearly preferable layered structures of the films, with layers parallel to the substrate surface. The results of IR showed organic components had been incorporated, and the position, pattern and intensity of spectral peaks of organic components changed clearly due to the chemical environment change after they self-assemble into the layered perovskite structure.The influences of annealing temperature on the crystal structure of the films were analyzed by using XRD, and it was found that heat treatment condition is important for the form of the desirable crystal structure. The as-deposited films were nominally amorphous and higher annealing temperature or longer time will result in decomposition of the films due to the loss of the organic component. Therefore, short time and low-temperature annealing after deposition was needed to improve crystallinity and phase purity. The surface morphology of the films deposited with different precursor concentration were observed using SEM, the results indicated that the concentration isn't suitable too high because higher concentration will result inrough surface. The (C6H13NH3)2PbL4 film deposited with 20mg/ml precursor concentration for 16 times was homogeneous, smooth and without cracks and the growing process of the film are similar to the Volmer-Weber pattern of the vapor deposition technique, which through discontinuous islands, netlike and finally becoming continuous film.The results of AFM showed the film-processability of (CnH2n+1NH3)2PbX4 system were excellent, smooth and continuous films having been acquired, in contrast, (RNH3)2CuCl4 system is poor.The room-temperature UV-Vis absorption spectra of the (CnH2n+1NH3)2PbX4 films were used to examine the effect on the optical properties of varying X and varying n, respectively, which showed a strong, clear exciton absorption peak. A significant red shift of the absorption peak was observed with varying X (X=CI,Br,I) in inorganic layers and the position of the exciton absorption peaks hardly shift with increasing of the alkyl chain length(n=4,6,8,10) in organic layers, suggesting the exciton absorption arise from electronic transitions within the inorganic layer, rather than from the organic layer. The room-temperature fluorescence spectra of the films also exhibit strong luminescence peaks in the visible range.
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