Study On The Stability Of Organic-inorganic Hybrid Perovskite Solar Cells

In recent years,organic-inorganic hybrid perovskite solar cells(HPVSs)with organic metal halide as light absorption material,has become a hot topic as a promising candidate in solar cells.With the development and application of a series of technologies including solvent engineering,element doping,interface processing and new hole-transport materials,the power conversion efficiency(PCE)of perovskite solar cells has been improved to 23.7% in a decade,approaching the efficiency of monocrystalline silicon.However,perovskite materials are particularly sensitive to illumination,heat,and water,especially.Long-term illumination,high temperature and high humidity will cause the decomposition of perovskite materials,which will deteriorate device performance,and limit the practical application of perovskite solar cells,hindering the industrialization.In order to prepare perovskite solar cell devices with high efficiency and stability,this paper mainly focuses on improving the efficiency and stability of perovskite solar cells in terms of structure optimization and modifying the preparation process of perovskite films.The reduced graphene oxide(rGO)was doped in the hole-transport layer(HTL)to improve the stability and efficiency of the devices.Graphene and its derivatives materials possess advantages in large surface area and excellent electrical properties.With a certain proportion of reduced graphene oxide added into HTL,the charge-carrier transport property was enhanced,leading to an increased efficiency of the device.At the same time,rGO can inhibit the migration of lithium ions inside HTL through the adsorption of lithium ions.The lithium ions were forbidden to migrate to the surface of HTL and absorb water reducing the degradation caused by water molecules,and improving the stability of the device.In addition,we also prepared perovskite films with smooth surface and large grains at low temperature through an optimized sequential coating method.To be specific,the precursor solution of lead iodide and partial cationic mixed was firstly spin-coated on substrates.Following,another precursor solution of the other cations was dipped on substrates dropwise while spin-coating.With employment of this new method,we realized smooth and continues perovskite film with large grain size at a relatively low temperature.And compared with the traditional two-step method,the efficiency of the perovskite solar cell based on this process increased from 17.6% to 19.2%,and the conversion efficiency could maintain within 400 hours.Considering the advantages and disadvantages of perovskite materials,the structures of solar cell devices and practical application demand,this paper proposed to improve the power conversion efficiency and stability of solar cell through optimizing the structure and adopting a modified coating method to prepare perovskite films.The successful results of the above research help to expand the application of perovskite solar cells and provide a new direction for the research on perovskite solar cells.Our findings will make contributions to further promoting the industrialization and commercialization of perovskite solar cells.