Study On The Preparation And Performance Of Flexible Heterojunction Perovskite Solar Cells

As a kind of promising new solar cells,perovskite solar cells have become current investigation focus in solar cell technology field due to their advantages including easy fabrication,high efficiency,and low cost.Among perovskite solar cells,the planar heterojunction perovskite solar cells can be prepared by using process compatible with the manufacture of flexible devices under relative low temperature.At present,the study of heterojunction perovskite solar cells is mainly focused on the improvement of perovskite thin film deposition process,the exploration of new hole transport layer materials,the modification study of interface layer and so on.The preparation method of planar heterojunction perovskite solar cells was studied in the paper firstly.Then we focused on the improvement of the performance and stability of the solar cells by interface layer modification.In addition,we introduced graphene and its derivatives as a hole transport layer into planar heterojunction perovskite solar cells,and carried out the preparation of flexible perovskite solar cells based on graphene transparent electrode.The main work and results are as follows:(1)The study of anode interface modification.In order to improve the energy level matching between the anode and the adjacent layer.Then MoO3 anode interface thin films were introduced to the solar cells with structure of ITO/ MoO3/ PEDOT:PSS /MAPb I3/PCBM/Ag.MoO3 anode interface thin films were prepared by thermal evaporation method.The results show that MoO3 modification improves the coverage of PEDOT:PSS on ITO substrates and blocks the corrosion of ITO electrode by PEDOT:PSS,which benefit for the improvement of the stability of the device and the elevation of the hole extraction efficiency.(2)The study of cathode buffer layer.In order to further improve the electron collection efficiency of perovskite solar cell.The sBCP and sBphen prepared by the solution method were used as the cathode buffer layer and introduced as the interface between the PCBM electron transport layer and the Ag electrode.The device structure was adopted as follows: ITO/PEDOT:PSS/MAPbI3/PCBM/(sBCP or SBphen)/Ag.The results show that the cathode buffer layer can play a role in blocking the diffusion of Ag atoms into the solar cells,improving the stability of the solar cells,increasing the electron collection capacity and elevating the PCE of the solar cells.(3)The application study of graphene and its derivatives in perovskite solar cells.We tried to use graphene as a hole transport layer,or use it with PEDOT: PSS to form a double hole transport layer for perovskite solar cells.It is found that the ammoniation treatment could improve the conductivity of graphene oxide and benefit its application as hole transport layer.In addition,monolayer graphene synthesized by CVD technology were used preliminarily as transparent electrodes for flexible perovskite solar cells.