Perovskite Solar Cells Based On ZnO Nano-array

Since the advent of perovskite solar cells in 2009,the efficiency has risen from 3.8%to 22.7%.The rapid development of the efficiency is related to the improvement of the cell structure,the electron transport layer and the hole transport layer besides the excellent properties of the material of CH3NH3PbX3(X = Cl,Br,I).In this paper,Zinc Oxide(ZnO)is used as electron transport material.A FTO/ZnO/CH3NH3PbI3/CuI/Au perovskite solar cell structure based on ZnO nano-array is proposed,and the photoelectric conversion efficiency of 1.09%cell devices has been successfully prepared.In this dissertation,firstly,the ZnO seed layer was prepared on FTO by sol-gel method,and the ZnO nano-arrays were grown on the seed layer by the solution bath method.Next,a perovskite light absorbing layer was prepared by evaporation-immersion method(i.e.,evaporation of PbI2 and immersion of CH3NH3I solution).Finally,the ZnO nanoarray perovskite solar cell used inorganic material CuI as the hole transport layer,and the silver colloidal electrode and the gold film electrode were prepared respectively.Changing the concentration of Zn2+ in the reaction solution can make the diameter of ZnO nanorods controllable in 50-125 nm.At the same time,the nanorods with a length of 550-1100 nm can be obtained by controlling the growth time.The thickness of the perovskite thin film is controlled by vaporing the PbI2 with a thickness of 220-2000 nm on the ZnO substrate and fully reacting by soaking 0.075 M/L of CH3NH3I solution for 180 s.The open circuit voltage of the FTO/ZnO/CH3NH3Pbl3/CUI structure was measured with the ZnO morphology and the perovskite layer thickness as variables.It is found that the nano-arrays grown in a zinc source concentration of 35mM/L for 1.5 h,and the perovskite thin film deposited with 0.1 g of PbI2 and fully reacted as the best process to prepare the cell.The maximum open circuit voltage of the cell reached 550 mV.It is found that the hole transport layer can protect perovskite thin film from destruction by conductive silver glue.Silver gel can block the water and oxygen in air and prevent the decomposition of perovskite material.In the vacuum deposition of gold electrode,the metal mask is used to control the size of the electrode,and the photoelectric conversion efficiency of the device is effectively tested.In the end,the perovskite solar cell with excellent performance was not successfully obtained.However,the devices based on FTO/ZnO/CH3NH3PbI3/CuI/Au structure have some feasibility both in principle and technology.In order to improve the efficiency of the cell,more in-depth study is needed.