Research On Interface Modification For CH₃NH₃PbI₃ Solar Cells And Microscopic Photoelectric Properties

CH₃NH₃PbX₃?X=Cl,Br,I?is a new material with the greatest development potential in solar cells.Due to having large absorption coefficient,freely controllable band gap,long carrier lifetime and bipolar carrier transport characteristics etc,it are widely used in the field of photovoltaics.At present,some groups have begun to prepare large-area,flexible perovskite solar cells,which is accelerating the pace of their market-oriented applications.However,expensive gold and hole transport materials are used in the preparation process,which makes the cost high.In this paper,commercial conductive carbon paste is used to replace gold and hole transport materials from the cost of reducing the preparation of perovskite solar cells.Explore the preparation process of hole-conductor-free perovskite solar cells.After optimization,the low-temperature carbon electrode perovskite solar cell was successfully prepared,which laid the foundation for the subsequent innovative research.Then,Meso-TiO₂ was modified with two kinds of amino acids.The results show that glycine can improve the interface between CH₃NH₃PbI₃ and Meso-TiO₂ layer,enhance the transfer efficiency of charge interface,and inhibit the recombination rate of electrons and holes,thus improving the photoelectric conversion efficiency of the device.Finally,the scanning Kelvin probe microscope?SKPM?and conductive atomic force microscopy?c-AFM?were used to study the photoelectric properties of two different CH₃NH₃PbI₃ planar heterojunctions at nanoscale.SKPM results indicate that different types of substrates have an effect on the E_F of CH₃NH₃PbI₃,and also affect the distribution and transport of charge.C-AFM shows that both planar heterojunctions show strong photocurrent at grain boundaries...