Study On Functional Layer Regulation And Stability Of Large Area Perovskite Solar Cell Module

In recent years,organic-inorganic metal halide perovskite semiconductors have been widely used in perovskite solar cells（PSCs）because of their high extinction coefficient,low density of defect states and low exciton binding energy.PSCs has developed rapidly since 2012,showing great development potential and industrialization prospects.However,at this stage,large-scale mass production applications of PSCs still face many challenges,such as the efficiency improvement of large-area components and long-term stability.PSCs has a stacked device structure,and the properties of each functional layer play an important role in the performance of the device.For example,the stability of commonly used organic hole transport materials is poor,which will directly affect the stability of the device;perovskite thin film deposition process is limited by the preparation process,there are a large number of defects in the bulk phase and interface,resulting in serious non-radiative recombination,which is also another important factor affecting the performance of the device.In addition,unpackaged PSCs devices are easily affected by the external environment,and direct leakage in the air will be eroded by water and oxygen,resulting in a serious decline in the performance of the devices during operation.For these reasons,the commercial application of perovskite solar cells is greatly limited.In this paper,pmuri-n perovskite solar cells are taken as the research object,and the charge transport layer,perovskite active layer and device packaging of PSCs are studied to improve the performance of large area PSCs.The main contents are as follows:First of all,a new scheme is designed to prepare inorganic hole transport materials for PSCs.In the experiment,Cu₂O thin films were prepared by electrochemical deposition,then perovskite precursor（MAPbI₃）solution was spin-coated on the surface of the precursor films,and high-quality CuI hole transport layers were successfully prepared after heat treatment.Perovskite layer can provide sufficient iodine source for iodization process,and PbI₂produced by perovskite degradation can play a passivation effect.The perovskite solar cells prepared in the experiment show a photoelectric conversion efficiency of～16.78%,and show good stability and almost no hysteresis effect.This is attributed to the fact that CuI has a high quality interface with fewer defects and a matching potential energy structure that promotes the migration/diffusion of carrier interfaces,which shows a good ability of hole extraction and makes photogenerated electrons/holes have matching mobility.The above work is also one of the reported good performances in the preparation of perovskite solar cells using cuprous iodide as hole transport material.Secondly,this paper explores the process of preparing large area perovskite thin films by template method,including the introduction of DMPU to optimize the active layer in order to increase the grain size.Firstly,CsBr and PbI₂thin films were deposited successively by thermal evaporation.The loose precursor films were obtained by the above method,and then the crystallinity and grain orientation of perovskite films were improved by introducing DMPU into organic cationic solution,thus small area（0.12cm²）～22.74%PCE and large area（64.8 cm²）～18.7%PCE were obtained.This is attributed to the fact that the introduction of DMPU helps to open the lattice of PbI₂to promote molecular exchange in FAI/IPA/DMPU solution,thereby promoting the growth of perovskite crystals and preparing perovskite thin films with large grain size.at the same time,it can also reduce the interfacial recombination of perovskite,which is helpful for the commercialization of perovskite solar cells.Finally,the stability of perovskite solar cells was successfully improved by using sputtering process to prepare PTFE thin film packaging PSCs.In the experiment,the packaging strategy of the combination of thin film packaging and cover plate packaging is adopted.In order to prepare more hydrophobic and denser thin films,the magnetron sputtering process was optimized in the experiment.Then,the changes of performance parameters of perovskite solar cells before and after packaging,the aging stability of packaged perovskite films at room temperature and heating at high temperature,and the tracking stability at room temperature of the devices after composite packaging were systematically studied.It is found that the thin film packaging layer can effectively improve the photothermal stability of perovskite and prolong the working life of the device.