Study On The Effect Of Air Moisture On The Stability Of Perovskite CH₃NH₃PbI₃

The perovskite CH₃NH₃PbX₃（X=Cl-、Br-、I-）has a cubic crystal structure,especially the typical perovskite CH₃NH₃PbI₃ material,with a band gap of only 1.55eV,carrier migration.The rate is 10 cm²/Vs and the light absorption range of 300-800nm.These excellent photoelectric properties make it a hot material in the field of optoelectronics.The perovskite CH₃NH₃PbI₃ material has such advantages in the field of optoelectronics,but in order to widely use its optoelectronic devices,it still needs to solve the material defects:First,the stability of CH₃NH₃PbI₃ material is poor,and it is easily decomposed when oxygen and water are encountered.The second problem is the pollution caused by lead in the material.Therefore,people are expected to study a lead-free,stable perovskite material.Here,the stability of the CH₃NH₃PbI₃ material is studied in this paper,mainly to study the effect of air moisture on the perovskite CH₃NH₃PbI₃ thin film and its solar cell performance.The result is as follows:1、The reaction mechanism of CH₃NH₃PbI₃ material with water was studied experimentally.The participation of polar solvent DMF was discussed and the stability of CH₃NH₃PbI₃ decreased.2、The effect of the preparation method of the perovskite CH₃NH₃PbI₃ thin film on its humidity stability was experimentally studied,and a new method for the preparation of a perovskite thin film was developed,namely the close-range evaporation-deposition method.The method first obtains a lead iodide film by vacuum evaporation,and then uses a close-range evaporation-deposition method to react at a low temperature of 100℃for 5 minutes to obtain a larger,denser and denser film of CH₃NH₃PbI₃.and it can be exposed to 40%relative humidity for 30days without decay,is conducive to the improvement of the stability of CH₃NH₃PbI₃.3、The structure of the perovskite CH₃NH₃PbI₃ thin film was improved by the close-range evaporation-deposition method to improve the stability of the CH₃NH₃PbI₃ thin film,so that it could be exposed to 70%relative humidity for 12hours without decomposition.