The Research On The Preparation And Optimization Of Perovskite Film And The Application In Solar Cell

In this paper,the CH₃NH₃PbX₃（X=I,Br）crystal was obtained by solvent evaporatin,and the CH₃NH₃PbX₃（X=I,Br）films were prepared by one-step solution method.The as-prepared samples were characterized by power X-ray diffraction（XRD）,scanning electron microscope（SEM）,UV-vis diffuse reflection and thermogravimetry（TG）.The effect of air with different relative humidity on the CH₃NH₃PbX₃（X=I,Br）films was investigated.Then we also discussed the factors that affected the uniformity and coverage of the CH₃NH₃PbX₃（X=I,Br）films from two aspects,including solvent,and annealing temperature.Finally,the solar cells based on CH₃NH₃Pb(I_1-xBr_x)3 were farbricated,and we also studied the effect of Br ratio on the performance of solar cells in detail.The thesis consists of the following three parts:（1）The onset absorption of CH₃NH₃PbI₃ crystal was 820 nm,which had a wide range of light absorption and could be used as sensitizer.The CH₃NH₃PbI₃ crystal could keep stable before 274 oC,when the temperature increased further,CH₃NH₃PbI₃ would decompose to PbI2.The CH₃NH₃PbI₃ film could maintain longer time when the humidity became lower.The CH₃NH₃PbI₃ films with better uniformity and coverage could be obtained by using DMSO as solvent and controllong the annealing temperature at 100 oC for 30 min.Then the mesoporous TiO2 film electrodes spin-coated with CH₃NH₃PbI₃ were farbricated to solar cells.Results showed that the open circuit（Voc）was 0.83 V,and the power conversion efficiency（η）could reach 10.62%.（2）The onset absorption of CH₃NH₃PbBr₃ crystal was 576 nm,of which the wide range of light absorption became narrower compared with CH₃NH₃PbI₃.The CH₃NH₃PbBr₃ crystal could keep stable before 261 oC,when the temperature increased further,CH₃NH₃PbBr₃ would decompose to PbBr2.The CH₃NH₃PbBr₃ film could maintain longer time when the humidity becomes lower and the stability of CH₃NH₃PbBr₃ was higer.The CH₃NH₃PbBr₃ films with better uniformity and coverage could be obtained by using DMSO as solvent and controllong the annealing temperature at 100 oC for 30 min.Then the mesoporous TiO2 film electrodes spin-coated with CH₃NH₃PbBr₃ were farbricated to solar cells.Results showed that the open circuit（Voc）was 1.00 V,and the power conversion efficiency（η）could reach 5.3%.（3）The desired CH₃NH₃Pb(I_1-xBr_x)3 solutions were made by stoichiometric mixing of synthesized CH₃NH₃PbI₃ and CH₃NH₃PbBr₃ solutions,then the CH₃NH₃Pb(I_1-xBr_x)3 films were obtained by one-step solution method.Then the TiO2 film electrodes coated with CH₃NH₃Pb(I_1-xBr_x)3 were used to farbricated solar cells.Results showed that the band gap of CH₃NH₃Pb(I_1-xBr_x)3 could be tuned controllably,which enable the realization of colorful solar cell.When the ratio of Br was 0.2,the maximum 11.67% in conversion efficiency under AM1.5G was obtained,this indicated that the introduction of Br could improve the performance of solar cell.