Double-interfaces Passivation Strategy In Perovskite Solar Cells And Blade Coating Preparation Of Large-area Perovskite Films

Nowadays,Perovskite solar cells(PSCs)have attracted widespread attention due to their excellent performance and the potential for low-cost production.Further improving the efficiency and stability of devices,developing fabrication methods for large-area perovskite films is the main direction of future research on PSCs.Accrding to the reported,interface properties of the device play an important role in the efficiency and stability of PSCs.The chemical properties,defect states,related energy level alignment,and charge distribution at the interface all affect the device efficiency.At the same time,ion diffusion and the resulting chemical reaction will further affect the stability of the device.Therefore,we first introduce a new type of interface passivation strategy to effectively reduce the surface and interface defects of the perovskite film and the accompanying recombination,to avoid the charge accumulation to improve the efficiency and stability of the device.Furthermore,we explore the preparation of large-area perovskite thin film by appling blade coating method,improve the liquid film flow kinetics by introducing a mixed solvent system,and optimize the process conditions of the blade coating to preliminary achieve a feasible large-area(?100 cm~2)preparation of perovskite films.The main research contents include:(1)In this work,the double-interfaces KCl passivation was used to achieve significant suppression of the interfacial recombination of the Ni O_x hole transport layer and the interfacial recombination of the PCBM electron transport layer in inverted planar Perovskite solar cells.The experimental results show that the double-interfaces KCl passivation can improve the morphology of the perovskite-type thin film,and then reduce the interface defect density and reverse recombination.The open-circuit voltage of the device was significantly increased from 1.02 V of the standard sample to 1.09 V after the double-sided KCl intervention.In addition,we also observed the diffusion behavior of ions in the device.At the same time,it is observed that the double-interfaces KCl modified device has a longer slow decay life and a shorter fast decay life than the standard sample according to the TRPL,which indicates that the modified device achieves more efficient charge extraction.Therefore,the double-interfaces KCl passivation can not only inhibit the interfacial recombination,but also improve the quality of the perovskite film and decrease the density of interfacial defects,the device efficiency has increased from 17.1%to 19.2%.After aging at the maximum power point for 1000 h,the device efficiency reach its initial 90%of the value.(2)This work adjusts the solvent engineering based on the preparation of large-area perovskite thin films,studies the complex flow dynamics of liquid films in different solvent systems,and systematically summarizes the role of solvent engineering in the thin film coating and drying process.In addition,this work optimizes various parameters of the blade coating process,including the blade coating speed,blade height,etc.,and summarizes the effects of different process conditions on film thickness and quality.With the anti-solvent immersion process,we have prepared a perovskite film with a mirror effect and fewer holes,and the roughness of the film can be controlled.In the effective area of 0.09 cm~2and 56 cm~2,the efficiencies of Perovskite solar cells and modules prepared by blade coating reached16.5%and 12.5%,respectively.