Preparation And Properties Of ZnO Electronic Transport Layer Of Perovskite Solar Cells

Perovskite solar cells(PSCs)have become a hotspot in the field of solar cells recently because of their low cost,simple preparation process and high photoelectric conversion efficiency.Electronic transport layer,an important part of solar cells,has a great impact on their performance.With advantages of wide bandgap,high electron mobility,simple preparation and low cost,ZnO nanomaterial is a major material of electron transport layer of perovskite solar cell.Therefore,the research and improvement of the preparation process and performance of the ZnO electron transport layer have a great significance for the research of solar cells.In this thesis,a series of ZnO powders and thin films with different calcination temperature,coating speed and Ce(rare earth element)doping concentration were prepared by sol-gel method and assembled into solar cells.The properties of the ZnO electronic transport layer performance has characterized by X-ray Diffraction(XRD),Electron Paramagnetic Resonance(EPR),Scanning Electron Microscopy(SEM),UV-Vis and J-V test system.The main conclusions are as follows:(1)In the process of preparing ZnO thin films by sol-gel method,the effects of different calcination temperature and coating speed on its properties were studied emphatically.When the ZnO powder is calcined at 500℃,the Zn O sample has good crystallinity and smaller grain size,which can improve the compactness of the film and the free electron content,so it is beneficial to the electron transport.When the ZnO thin films were coated at 4000 rpm,the surface morphology was uniform and has a better transmissivity.(2)ZnO powders and films with different Ce3+ doping concentrations were prepared under the optimum conditions.The doping of Ce3 + ions can make the ZnO crystal structure undergo some distortion,and the grain size is the smallest when the doping amount is 2%.With the increase of the doping amount,the grain size and the number of free electrons increase too,and the transmittance of the ZnO thin films is gradually reduced.(3)The optical absorption layer,prepared by one-step method,and ZnO electronic transport layer are used to assemble the perovskite solar cells.The J-V curves showed that the photoelectric conversion efficiency of the PSCs is highest at 6.77% when the ZnO electron transport layer is coated at 4000 rpm.While in the doped samples,the lower concentration of Ce3+ doping can improve the conversion efficiency.When the doping amount is 1%,the photoelectric conversion efficiency is 6.84%,and the results accord with other characterization and analysis.