Researchon The Morphology Control Of Absorption Layer Of Perovskite Solar Cells Prepared By Vapor Deposition

In recent years,with the gradual improvement of the industrial level and the gradual exhaustion of primary resources,mankind will rely more on clean and renewable resources.Solar energy is a clean,natural,and effective energy source,so it has always occupied the major Research hotspots of energy agencies.Solar cells can effectively convert solar energy into electric energy,which is convenient for people’s production and life,reduces environmental pollution,and accelerates the process of human industrialization,informationization,and sustainability.Although silicon solar cells have become the mainstream application in the market,the problems of difficult preparation,low efficiency,and high cost have been difficult to effectively solve.As a newer device that converts clean energy into electrical energy,perovskite solar cells have the advantages of high carrier mobility,long diffusion length,adjustable band gap,high efficiency,and low cost of preparation.Under the background of continuous development and environmental issues that are increasingly concerned by all walks of life,it has become one of the popular research objects in the scientific research field.From the 3.8%efficiency when it was first developed in 2009,the device efficiency exceeded 25%this year.In recent years,people have made considerable progress in the research of perovskite solar cells.The light-absorbing layer is a very important part of the perovskite solar cell.Its quality directly determines the performance and efficiency of the entire cell.Therefore,the research on the preparation process of the CH₃NH₃PbI₃ thin film of the light-absorbing layer of the perovskite solar cell is also an important research direction in this field in recent years.The main research object of this paper is the CH₃NH₃PbI₃ film of the light-absorbing layer of the perovskite solar cell.First,the perovskite CH₃NH₃PbI₃ film is prepared by the small aperture screen isolation technology combined with the vapor deposition method.The morphology of the CH₃NH₃PbI₃ film is controlled by temperature and time;The morphology control of the CH₃NH₃PbI₃ thin film of the light-absorbing layer of the perovskite solar cell is carried out by doping with rare earth ions(Ln³⁺=Eu³⁺,Dy³⁺)under the optimal preparation process conditions.The specific research is divided into the following two aspects.1.The perovskite CH₃NH₃PbI₃ film is prepared by vapor deposition method which is different from the general preparation method,and the CH₃NH₃I crystal powder and PbI₂film are vapor deposited in a closed container using the small aperture screen isolation technology to obtain the perovskite CH₃NH₃PbI₃ film.Control the reaction temperature and reaction time to control the morphology of the film.After research,it is found that the perovskite CH₃NH₃PbI₃ film with high crystallinity,no pinholes,strong compactness,high coverage,high absorption characteristics,high fluorescence intensity,high fluorescence lifetime,and high quality can be prepared by reacting at 110℃for 9 minutes.The battery devices prepared under these conditions（because the research only focuses on the perovskite CH₃NH₃PbI₃ film,none of the prepared battery devices have undergone surface passivation treatment）open circuit voltage is 1.002 V,and the photoelectric conversion efficiency is 15.16%.It shows that the use of small aperture wire mesh isolation technology provides a new idea for the preparation of high-quality,good-morphology perovskite CH₃NH₃PbI₃ thin films by vapor deposition.2.Under the conditions of optimal reaction temperature and reaction time,using small aperture wire mesh isolation technology to dope rare earth ions(Ln³⁺=Eu³⁺,Dy³⁺)into the perovskite CH₃NH₃PbI₃ film,which is not only conducive to reducing the perovskite film material The lead content can also be used to control the ion valence state of the rare earth ions in the perovskite material to achieve the purpose of improving the film quality,controlling the film morphology,and enhancing the stability of the film.When the Eu³⁺ion concentration is 2%,it can be prepared.The open circuit voltage of the perovskite solar cell device can reach 1.042 V,the short-circuit current density is 21.02 m A/cm2,the fill factor reaches 77.85%,and the photoelectric conversion efficiency（PCE）is 17.05%,which is12.5%higher than that of the undoped one,and After being exposed to air for a period of time,the morphology and performance of the film and device efficiency are better than those obtained under other conditions.