Research On High Performance Perovskite Photodetector Based On Blade Coating Method

The solution manufacturing method of perovskite photodetectors has attracted much attention because of its advantages such as low cost,light weight,easy processing and easy bending.At present,the detector prepared by spinning coating method in laboratory has shown excellent detection performance.However,this low flux preparation method cannot meet the needs of large-scale production and application,which greatly limits the application range of detectors and hinders the commercialization process of large-area detection imaging.As a continuous manufacturing process,blade coating has become one of the most successful methods in the industrial production of devices because of its simplicity and versatility.The devices based on the blade coating method can not only give full play to the advantages of large-scale continuous preparation in the field of photovoltaic cells,but also have considerable prospects and commercial value in the field of large-area detection and imaging.However,the research on perovskite blade coating device is far less thorough than spin coating method,and the preparation technology and performance of the scraping device still need to be further perfected and improved.This paper analyzes the above problems and mainly studies the contents of the following two parts:Firstly,as an innovative device preparation method,the blade coating method provides a new idea for the preparation of large-area devices.However,during the production process,the growth and performance of the film are often greatly affected by the blade coating temperature and the concentration of precursor solution.Moreover,the influence of transport layer thickness on device performance can not be underestimated.Therefore,in order to obtain high-quality devices and improve the original performance of devices as a whole,we have gradually explored the conditions of each step from the film to the device during the preparation process,and conducted PL,XRD,SEM,J-V,EQE and other tests to characterize the film and devices,and finally found out a relatively perfect and mature process.At the optimum blade coating temperature,Ra（arithmetic mean deviation of contour）decreases from the highest 9.5nm to 4.24 nm,and the quality of the film is significantly improved,which solves the problem of high surface roughness caused by temperature in the blade coating process.With the optimization of the concentration of perovskite precursor liquid,the final device EQE successfully reached about 70%,and the blade coating device with good performance was prepared.By studying and optimizing the thickness of the transmission layer of the device,the response time is shortened to 1.8 ms compared with 4.07 ms before optimization.It lays a good foundation for the following work.Secondly,we carried out blade coating based on the above exploration conditions,and improved and optimized the unnecessary defects caused by various uncontrollable factors in the preparation process,as well as serious ion migration phenomenon and other problems.Finally,a non-fullerene（WZM-7-A-b）doping passivation method based on blade coating method is proposed,which can significantly improve the performance of the device,along with the increase of life.The dark current density of the device added with WZM-7-A-b is 5×10^-6 m A cm^-2,which is reduced by nearly one order of magnitude.After 12.5 hours of continuous testing,the dark current drift is as low as 0.071×10^-7n A cm^-1V^-1S^-1.Then a large area detector of 18.72 cm² 8×8 was prepared based on the blade coating method.The imaging applications of three different J,L and U patterns have been successfully completed.In this paper,through the blade coating method of photodetector research,and constantly explore the film and device preparation technology,obtained good performance of the original device,and in view of the original device defects more problems,further through the doping of WZM-7-A-b to improve the performance of the device,detector life growth,and the principle of analysis.Finally,the imaging application of large area photodetector prepared by blade coating method is completed.At present,there are limited references and related researches in the field of large area photodetectors prepared by blade coating method.It is believed that this research will play a very important role in the future exploration in this field and promoting the commercialization of large area devices.