Preparation And Characterization Of Organic-inorganic Hybrid Metal Halide Perovskite Films

Hybrid organic-inorganic perovskite-based solar cells （PSCs） have garnered significant attention since first reported six years ago. Over the same period, PSC conversion efficiencies have improved from below 4% to values presently exceeding 20%, and are rapidly approaching the benchmarks set by leading thin-film technologies. In association with their impressive performance, PSC devices boast immense potential for low material and manufacturing costs compared to other photovoltaic technologies. The high efficiencies achieved with these PSC architectures further complicates any correlation between the perovskite morphology and the device performance. Control of the perovskite morphology in planar PSCs is strongly influenced by the fabrication technique employed.In this thesis, we use components-structure-band gap-photoelectric property to study the preparation and characterization of perovskite thin films. The CH3NH3PbX3 （X= Br, I） hybrid perovskite thin films were spin-coated with different molar ratios of CH3NH3I to PbI2. Through analyzing crystallinity, morphology, UV-visible light absorption spectrum, stability and transport properties respectively, the influence of the organic content on optical band gap and the photoelectric properties of these films was studied.According to our study, the organic content of the precursor solution has a significant impact on the film morphology and optical band gap. With the organic content decrease, these perovskite films exhibited larger grains. With the reduced portion of the organic content of the two kinds of perovskite thin films, the absorption edge, showed in the UV-visible absorption spectrum, has a red shift to the longer wavelength.In our study, we found that the PL intensity of MAPbBr3 film can be tuned by simply modifying the organic content. When the k= 2, the MAPbBr3 film exhibits unusual photoluminescence intensity. And we also know that the optical bandgap of MAPbI₃ film could be gradual tuned from direct bandgap to indirect bandgap by changing the organic content of the MAI. The indirect bandgap of MAPbI₃ film was found in experiment study.