Trap Passivation Study In Fa/Ma-based Perovskite Solar Cell

Binary（FA/MA）perovskite solar cells are a new type of perovskite solar cell that has been developed in recent years and has attracted attention due to its high photoelectric conversion efficiency and better stability.Compared to single perovskite solar cells,the preparation method of binary perovskite solar cells is relatively simple,with lower cost and good application prospects,making it one of the research hotspots in the field of solar cells.However,in practical applications,binary perovskite solar cells often suffer from problems such as a large number of defects on the surface of the thin film and band mismatch between the active layers of the cell,which affects their photoelectric conversion efficiency and stability,thereby hindering their commercial development.In response to these problems,this paper added additives,（such as carbide nitride:g-C₃N₄ and oxycarbide nitride:g-C₃N₄-O）,to the electron transport layer,and additives,(such as phenethylamine iodide:PEAI,phenethylamine acetate:PEAAc and 2-（1-cyclohexenyl）to the perovskite layer,respectively.The research team explored the passivation mechanism of additives by comparing different groups of the same type of additives.The specific work is as follows:（1）A functional electron transport layer was fabricated using oxycarbide nitride（g-C₃N₄-O）to passivate the defects in the layer.Compared with the passivation effect of g-C₃N₄,g-C₃N₄-O exhibited superior.On the one hand,g-C₃N₄-O can react with-OH on the surface of Sn O₂,resulting in the removal of-OH defects on the surface of Sn O₂ through a chemical reaction.On the other hand,g-C₃N₄-O can also interact with the Sn dangling bonds on the surface of Sn O₂,thereby reducing the defects caused by oxygen vacancies in the electron transport layer and improving the photoelectric conversion efficiency of the device.Additionally,the interaction between g-C₃N₄-O and the perovskite light-absorbing layer also contributes to improving the stability of the device.（2）Three different organic materials with distinct functional groups（PEAI,PEAAc and 1-Cy Hn EAI）were utilized to post-treat the perovskite film,passivating the defects present on the surface of the film.Compared with the anionic component of PEAI,Ac^-generated additional Pb I₂ on surface of the perovskite film,resulting in a reduction of the hysteresis effect and the short-circuit current density has increased by 1.5%.At the same time,its stability has also been improved.Compared with the cationic part of PEAI,1-Cy Hn EA⁺and the perovskite film generate a 2D/3D composite perovskite material,which not only passivates the defects of the perovskite film but also alleviate energy band mismatch between the perovskite layer（PVK）and the hole transport layer（HTL）,thereby reducing the energy band mismatch problem and the open circuit voltage of the device has increased by 2.8%.