Study On The New Type Of Inorganic Hole Transport Layer For Perovskite Solar Cells

In recent years,the study of perovskite solar cells has experienced a rapid development with the improvement of the attention to the clean energy of sunlight,and its conversion efficiency is constantly improved.The planar heterojunction perovskite solar cells have the advantages of low temperature preparation and simple preparation,and are easy to be used in the preparation of flexible devices.These features attract the attention of a large number of researchers.The battery structure in this paper is based on the inverse planar heterojunction structure,which is ITO/HTL/Perovskite/PCBM/BCP/Ag.In this structure,the hole transmission layer has an important effect on the performance of the battery.In this paper,by using the inorganic hole transporting material to be the HTL,which has the advantages of high mobility,wide bandwidth and low cost,we explored the effect of inorganic materials on the film formation of perovskite active layer,and the effect of interface defects on the performance of the battery.The main contents and results are as follows:（1）By comparing the two step solution method,one step DMF solvent method and one step DMF&DMSO solvent method,we found that the active layer prepared by the two step method is not dense enough and has defects.By using one method,the evenness and compactness of the active layer can be greatly improved.The addition of DMSO can further slow down the film forming rate of the perovskite active layer,making the obtained active layer more compact and smooth,and the conversion efficiency of 11.45%can be obtained.The hysteresis effect of the battery is optimized by adjusting the thickness of the PCBM.When PCBM is thinner,it can not completely cover the surface of the active layer,and there is leakage current,and the accumulation of charge at the interface will be produced.By thickening PCBM can make the equivalent capacitance area close to the area of the device,reduce the accumulation of charge and eliminate the hysteresis effect.But too thick PCBM will also cause the increase of the series resistance,which reduces the efficiency of the battery.（2）The use of CuI,MoOx and Cu₂O as the hole transport layer is used in the battery.Cu I was prepared by solution spin coating and vacuum evaporation.MoO_x was prepared by vacuum evaporation and magnetron sputtering.Cu₂O was prepared by solution spin coating and magnetron sputtering.The inorganic thin films prepared by various methods are used as HTL,so as to achieve better device performance.The effects on the film formation of the active layer and the defects in the interface are analyzed.It is found that the single inorganic hole transport layer is prone to the existence of defects in the active layer,and the interface defects between them also affect the transport of the carrier.（3）A double hole transmission layer of CuI/PEDOT:PSS,MoO_x/PEDOT:PSS and Cu₂O/PEDOT:PSS is obtained by depositing a layer of PEDOT:PSS on the inorganic hole transport layer.By optimizing the contact between the hole transmission layer and the active layer,the better morphology of the active layer was obtained.And it can reduce the interface defect partially and improve the efficiency of the battery,and the optimal conversion efficiency is 15.48%.In this paper,the effects of the energy level,interface contact and interface defects between different layers on the performance of the cell are mainly studied.It is of certain significance for improving the performance of the perovskite solar cell by using the inorganic hole transport layer.