Interface Regulation And Performance Investigation Of BA-based Quasi-two-dimensional Perovskite Solar Cells

In recent years,researchers have carried out deeply research on three-dimensional（3D）perovskite,and photoelectric conversion efficiency（PCE）based on 3D perovskite solar cells（PSC）has broken through 25%.However,the instability of 3D perovskite significantly limits the further industrial application of PSC.Two-dimensional（2D）perovskites extended by introducing bulky organic amine cations as spacers into the 3D perovskite structure exhibit excellent stability,showing its unique advantages as an active layer of the PSC.However,the insulating properties of organic amines will hinder the transmission of carriers and affect the performance of devices,at the same time,the mismatch of energy level and poor contact between the carrier transport layer and the light absorption layer will further limit the development of 2D PSC.Therefore,the research on the transport layer of2D PSC has also become a research highlight.Based on these problems,this paper mainly studies from the following aspects:A simple method was developed to modify the traditional PEDOT:PSS hole transport layer.The PEDOT:PSS solution was doped with cuprous chloride ammonia solution（CuCl-NH₃[aq]）to form a composite hole transport layer（PEDOT:PSS-CuCl）.Research has shown that the HOMO level of the composite hole transport layer is more matched with the butylamine（BA）-based 2D perovskite,which can effectively improve the hole extraction and transfer efficiency.Based on the uniqueness of2D perovskite,Cl^-can act as a nucleation site to promote the growth of the inorganic layer of 2D perovskite crystal perpendicular to the substrate,which is beneficial to the transport of charge carriers.Further research confirmed the PCE of BA-based 2D PSC（n=4）based on composite hole transport layer reached 13.36%,which was 19%higher than that of the control device（11.16%）.The doping of CuCl improves the surface morphology of 2D perovskite films,reduces the surface microcracks and roughness and passivates the defect of the films.In addition,the stability of 2D PSC has been significantly improved.After exposure to air for 480 h,the PCE of 2D PSC based on PEDOT:PSS-CuCl composite hole transport layer do not decrease significantly,while the PCE of control device only maintain 70%of the initial efficiency.A simple method was used to modify the electron transport layer PCBM of 2D PSC.The mixed solution of chlorobenzene（CB）and isopropanol（IPA）is used to dissolve PCBM.Compared with CB solution,the mixed solvent enables better wetting of the PCBM solution on the surface of the perovskite film,which can effectively improve the spreadability of PCBM solution on the 2D perovskite film.The doping of IPA forms a smoother and flatter PCBM film,which is beneficial to the transfer and transport of electrons.The PCE of 2D PSC based on PCBM-IPA:CB films increased from 10.91%to 12.79%.In addition,the stability of the modified 2D PSC has been improved.After exposure to air for 480 h,the PCE of the devices can still maintain 85%of the initial efficiency.