Preparation Of Perovskite Solar Cells By Mix-vapor Deposition

Perovskite solar cells have become a research hotspot in the photovoltaic field in the past decade,and their photoelectric conversion efficiency has reached 25.2%.Stability and large-scale industrial preparation methods are currently the key factors restricting the commercialization of perovskite solar cells.At present,the preparation of perovskite solar cells is mainly carried out using the solution method.The solution method has the advantages of simple operation and easy control,but it will produce a large amount of residual toxic solvents during the preparation process,which is not conducive to large-scale commercial production.The vapor deposition method is a mature industrial process for preparing semiconductor materials and devices,which is suitable for large-scale production,and at the same time avoids the disadvantages caused by the solution method preparation.However,the highest photoelectric conversion efficiency of the device prepared by the vapor deposition method is only20.13%,which is a certain gap compared to the solution method.The fundamental reason is that the vapor deposition method cannot be as convenient and accurate as the solution method in the control of the material structure.Therefore,the work of this paper explores the problem of dimensional control of the perovskite thin film structure in vapor deposition preparation,and explores vapor deposition through the development of new processes and the resulting perovskite layer structure,photoelectric properties,and carrier transport laws.The law of thin film structure and performance regulation in perovskite,explore ways to further improve the performance of materials and devices.The research content and results include the following three aspects:?1?Based on the FTO/TiO₂/MAPb I₃/spiro-OMe TAD/Au structure,comparing the efficiency differences of devices prepared with different purity Pb I₂,it was found that when the purity of Pb I₂ was increased from 98%to 99.999%,the conversion efficiency of the device was increased from 14.65%to 17.8%,it shows that the purity of Pb I₂plays a significant role in improving the efficiency of the device in vapor deposition.?2?Aiming at the difficulty of the vapor deposition method to control the structural dimension of perovskite,the hybrid vapor deposition method was developed to control the structure dimension of perovskite thin film.In the study,we used the mixed vapor of BAI?CH₃CH₂CH₂CH₂NH₃I?and MAI?CH₃NH₃I?to react with the Pb I₂ film.By controlling the chemical mass ratio of BAI and MAI,we successfully achieved the index of the two-dimensional perovskite film with n of 1,2,3,4,and 5,and prepared photovoltaic devices.?3?Based on the mixed vapor deposition method,the mix vapor of PEAI?C₆H₅CH₂CH₂NH₃I?and MAI is used to react with the Pb I₂ film,and the structure and band gap of the perovskite film are adjusted by controlling the chemical mass ratio of PEAI and MAI to prepare a high-quality mixed dimension perovskite film.The conversion efficiency of photovoltaic devices based on this hybrid perovskite film reaches a maximum of 18.08%,and it can be maintained at an initial efficiency of 87%when placed in a 55%humidity environment for one month.By analyzing the transient motion and spatial distribution behavior of its carriers,we found that a small number of two-dimensional structures in the three-dimensional structure are helpful for carrier separation and transportation.