Regulation Of Photoelectric Performance Of Two-dimensional Perovskite Solar Cells

Two-dimensional perovskite solar cells(2D PSC)exhibit great potential for commercialization due to their excellent stability.In recent years,although the development of 2D perovskite solar cells is very rapid,its low energy conversion efficiency limits its commercial application.Thus,improving the energy conversion efficiency of 2D perovskites has always attracted people to explore.From the perspective of the 2D perovskite structure,large-sized organic cations play an important role.The stability of 2D perovskite devices comes from the organic cation,but it also leads to lower carrier transport efficiency.In addition,crystal orientation has an important effect on carrier transport.Vertically grown crystals will provide favorable channels for carrier transport and promote carrier transport.In addition,the heterogeneous spatial distribution is another factor that restricts the performance of 2D perovskite devices.The energy transfer and charge transfer of 2D perovskite devices are different from 3D due to multiple low-dimensional phases in2D perovskite devices.In this paper,the performance of 2D perovskite solar cells is improved and regulated by chemically fluorinating organic cations and changing the phase structure.The results obtained are as follows:1.Based on PEA~+,the organic cation 4FPEA~+was obtained through fluorination treatment.Compared with PEA~+,4FPEA~+makes 2D perovskite crystal growth more vertical.In addition,2D perovskite devices based on 4FPEA~+show larger grain size,denser films and higher crystallinity.2.By regulating the phase distribution,the carrier transport efficiency in 2D perovskite devices is improved.The charge diffusion length,carrier activation energy,and carrier mobility show that the improved phase distribution greatly improves the carrier transport.Based on the thickness of the 610 nm perovskite layer,an energy conversion efficiency of 17.3%was achieved.This value is close to the highest efficiency(18.2%)currently reported in 2D perovskite solar cells.Our work provides effective measures for improving the performance of 2D perovskite,and has certain guiding significance for promoting the development of 2D perovskite.3.Due to stronger hydrophobicity of 4FPEA~+,fluorinated 2D perovskite devices show excellent humidity stability.After 300 hours of storage in high humidity(55±5%),unpackaged devices can maintain their initial efficiency more than 83%.