| Organic-inorganic hybrid perovskites have the characteristics of high absorption coefficient,low defect density,high exciton binding energy and low auger recombination rate,these superior properties make it have an inestimable application prospect in the optoelectronic fields of solar cell,light-emitting diode,laser,detector and so on.Besides,the synthesis and preparation method of organic-inorganic hybrid perovskite is simple and easy to operate.It can be grown and prepared on different substrates,quantum dots,nanowires/sheets,micron lines/sheets/blocks,large size single crystals and thin films of the order of millimeter or even centimeter can be prepared by solution method at room temperature.Furthermore,by changing the halogen composition,the absorption and emission wavelength of organic-inorganic hybrid perovskites can be continuously adjusted in the ultraviolet-visible to near infrared region.Despite its excellent performance,there are still many necessary problems to be solved.the most important is how to effectively improve its stability,organic-inorganic hybrid perovskite are extremely sensitive under the changing conditions of light,humidity and temperature,and it is easy to decompose under the existence of bright light,high humidity or high temperature,which hinders its large-scale commercial application to a great extent.To further improve its environmental stability,methylammonia-lead-bromide perovskite(CH3NH3PbBr3)was chosen as the study sample in this thesis.Firstly,starting from the method of experimental synthesis of CH3NH3PbBr3,by changing the synthesis method,raw materials and conditions,the micro-nano regulation of CH3NH3PbBr3 was successfully achieved,and CH3NH3PbBr3 materials with different structures and stable properties were obtained,including CH3NH3PbBr3polycrystalline film,CH3NH3PbBr3 single crystal micron block and CH3NH3PbBr3micron arrays.To improve its stability,CH3NH3PbBr3/ZnO composite and CH3NH3PbBr3@Pb Br OH composite were designed and synthesized.Then the structure,properties and functions of the above materials are studied in detail.The main research contents and results of this paper are as follows:1.The experimental scheme of preparation of CH3NH3PbBr3 perovskite material by solution method was improved and optimized.The structure of polycrystalline film,single crystal block and arrays of CH3NH3PbBr3 perovskite material was synthesized by changing the concentration of lead source material and the placement mode of substrate material in the preparation process of CH3NH3PbBr3 perovskite material.The influence of the concentration of lead source material on the synthetic material was studied,and it was found that the CH3NH3PbBr3 polycrystalline film was easily generated by the low concentration of anhydrous lead acetate,and the three-dimensional CH3NH3PbBr3 single crystal micron block and micron array were easily generated by the high concentration of anhydrous lead acetate combined with the inverted placement of the substrate.The structure and morphology of CH3NH3PbBr3 polycrystalline film,micron single crystal block and array were characterized on the basis of synthesis.2.The photoelectronic properties of CH3NH3PbBr3 polycrystalline films,micron single crystal blocks and arrays are systematically studied.The luminescence peak and absorption band edge of CH3NH3PbBr3 polycrystalline film are at 532 nm and564 nm respectively,the photoelectric detector is constructed based on CH3NH3PbBr3polycrystalline film material,the dark and light current under 1 V bias voltage of the device is 1.8×10-7 A,1.18×10-6 A,on-off radio is 6.5.CH3NH3PbBr3/ZnO material was constructed by RF sputtering technology and the CH3NH3PbBr3/ZnO photodetector was constructed based on the material system.The dark and light current under 1 V bias voltage of the device is 4.0×10-8 A,8.5×10-7 A,and on-off radio is up to 16.3,the stability of the device is significantly improved then single CH3NH3PbBr3films under the light of 365 nm and 405 nm.In addition,by screening the size of micron blocks,laser emission was obtained at lower pump power.3.Based on the improved bottom seed solution method and using lead acetate trihydrate as seed layer material,the"core-shell like"high stability CH3NH3PbBr3@Pb Br OH composite material was designed and synthesized.The composite structure CH3NH3PbBr3@Pb Br OH is a"core-shell like"structure,which the main body is Pb Br OH rods with CH3NH3PbBr3quantum dots embedded inside.Based on the composite material,the photoelectric detector is constructed.Under the bias pressure of 1 V,the rise and decay time are 0.32 s and 0.11 s respectively,with a fast response time and significantly improved device stability. |
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