Preparation And Optimization Of Multi-halogen Ion High-efficiency Perovskite Solar Cells And Blade-Coating Perovskite Solar Cells

Organic-inorganic hybrid perovskite solar cells have received widespread attention due to their excellent photovoltaic performance,simple processing technology and low cost.Now the power conversion efficiency of perovskite devices has exceeded 25%.However,there are still many problems to be solved in perovskite solar cells.The polycrystalline perovskite films prepared by the thermal annealing process have high density defects in the interior,surface and grain boundary.The key to improving the efficiency of hybrid perovskite solar cells is to improve the crystal quality and reduce the defects of light absorbing layer.The stability and large area fabrication process of perovskite solar cells also need to be improved.Therefore,this thesis mainly improves the efficiency and stability of perovskite solar cells devices through two aspects:component control and interface passivation.The crystalline quality and surface morphology of the perovskite film,the internal defects and carrier transport of the perovskite active layer,and the carrier transport kinetics of perovskite solar cells have been systematically studied.At the same time,the preparation method and scraping process of large area perovskite solar cells are explored under atmospheric conditions,which provides a certain reference for the commercial application of large area perovskite solar cells.Firstly,we improve the efficiency of perovskite solar cells devices through component adjustment.By adding the MAPb BrCl₂component to the tri-cation perovskite precursor solution of the pure iodine system to introduce poly-halide ions,we also systematically studied the effect of different contents of MAPb BrCl₂ on the device efficiency.Our research found that the appropriate amount of MAPb BrCl₂ component can effectively improve the crystalline quality of the perovskite,significantly improve the efficiency of the perovskite solar cells device.the perovskite crystallization can be adjusted to make the perovskite grains larger in extent,which will reduce the defects related to the grain boundary and inhibit the perovskite crystallization Phase decomposition.it can also reduce the surface roughness of the perovskite film.The addition of an appropriate amount of MAPb BrCl₂component can also have a certain passivation effect on the inside of the perovskite film crystal,which can effectively improve the transport and extraction of carriers,reduce the accumulation of internal charges in the device,and recombine defects to reduce internal defects.Thus,We finally fabricated perovskite solar cells with an efficiency exceeding 20%.we used[CH₃PPh₃]⁺Br^-to passivate the surface and grain boundary defects of the organic-inorganic hybrid perovskite active layer.We systematically studied the effect of[CH₃PPh₃]⁺Br^-in perovskite solar cells.After research,it is found that the[CH₃PPh₃]⁺Br^-can effectively reduce the surface roughness of the perovskite film without causing the crystallization and inhibiting the absorption of the perovskite solar cells.A proper amount of[CH₃PPh₃]⁺Br^-can have a good passivation effect on the surface defects of the perovskite.It reduces the defect state density of the film,inhibits the recombination of carriers at the interface,and improves the energy conversion efficiency of the device.Finally,perovskite solar cells with an efficiency of 21.4%were fabricated.At the same time,it can improve the stability of perovskite solar cells.It can maintain a stable output of more than 96%in 600 seconds under the simulated light conditions at the maximum power point.Finally,We have systematically studied the blade-coating process of perovskite batteries,and have specifically explored the process of blade-coating perovskite batteries under atmospheric conditions and successfully prepared solar cells devices.After we determined that the electron transport layer blading speed was 5m/s,and the perovskite solar cells with the substrate temperature at 40°C performed best.On this basis,we studied the scratch-coating process of the perovskite active layer.In an air glove box,we used a two-step blade-coating method to deposit the perovskite film.Under the condition of low substrate temperature,it is easy to form a perovskite film with no obvious holes on the surface;it is difficult to form a film at higher temperature,but the success rate and repetition rate of the experiment are still relatively low,both of which illustrate the two-step squeegee preparation process existing room for improvement.We hope that our exploration of the process of scraping perovskite cells under atmospheric conditions will have a certain reference value.The focus of this thesis is to improve the efficiency and stability of perovskite cells through component control and interface passivation.There is a certain technological exploration for large-area blade-coating perovskite solar cells under air conditions.They have a certain role in promoting the industrialization of organic-inorganic hybrid perovskite batteries.