The Study On The Fabrication Process Of The Planer Heterojunction Perovskite Solar Cells And The Influence Of The CH₃NH₃I Post-treatment On The Performance

Perovskite has been widely used in solar cell devices because of their excellent photoelectric characteristics.The photoelectric conversion efficiency was quickly increased to 22.1%from 3.8%when they first introduced.Many fabrication methods were put forward in these years,and the solution spin coating technology,which usually adopt mesoporous structure is widely used.High temperature sintering,which is not conducive on the application of flexible substrate and large scale manufacturing,is inevitable in the mesoporous fabrication procession.This work optimizes the solution spin coating preparation procession of perovskite film based on planar heterogeneous structure,and improves the photoelectric conversion efficiency,and puts forward the MAI post treatment to ameliorate the quality of perovskite film.The solution spin coating method can be divided into two-steps and one-step coating method according to the preparation process.The experiment proved that using the two-step solution spin coating method can form a uniform and dense planar layer on the transmission layer(PEDOT),but it will limit the absorption and charge transfer,because the uncovered PbI2.The use of simple one-step solution spin coating avoids the problem of incomplete reaction.However,after a series of improvements,all devices fabricated by this method are shorted.Therefore,the method of solvent assisted is introduced,adding solvent DMSO in the precursor solution of simple one-step solution will combine with PbI2 and MAI and form an intermediate compound to control the reaction process to avoid uneven reaction.The experiment proved that can effectively improve the quality of Perovskite Thin Films by this method,more compact and uniform films to avoid short circuit,also found that the content of DMSO in solution can not only regulate the uniformity of the film surface,can also control the thickness of Perovskite Thin films.Based on the absorption spectrum,surface morphology and J-V curve,the DMSO content can be determined,and a better perovskite solar cell device can be obtained.In addition,the quality by introducing the elemental chlorine in the precursor solution to improve perovskite films and improve the method of device performance will lead to impurity PbI2 and MAPbCl3 appear in the perovskite thin film,thin film of MAI postprocessing aimed at the question.After the MAI solution was spin coated on a film surface impurities,MAI can penetrate and to participate in the re construction of perovskite crystals,removing impurities,improve the morphology,improve the absorption,the photoelectric conversion efficiency of the device is further improved.