Study Of Performance Optimization For Perovskite Solar Cells By Controlling The Perovskite Active Layer Crystallization

Perovskite solar cells have quickly become a strong candidate for next-generation solar cells due to their low cost,solution processing,and high power conversion efficiency?PCE?.At present,the highest PCE has reached22.7%.The key factor affecting the efficiency of perovskite solar cells is the quality of the perovskite active layer.Therefore,the production of perovskite active layer is particularly critical,and effective control of its crystallization is an important research direction for obtaining high-quality active layers.In this article,we have done some work on the preparation of high-quality perovskite active layers,as follows:?1?In the third chapter,we used one-step method for the preparation of perovskite films.For this method,the formation of the intermediate phase has an important impact on the crystallization of the perovskite layer and the quality of the film,we adjust the anti-solvent polarity by mixing anti-solvent,that would lead to different Dimethyl Sulfoxide?DMSO?extraction capacity,to obtain the optimal crystallization rate and the intermediate phase ratio,and the film quality was improved.The Fourier transform infrared spectroscopy of the perovskite film was characterized,and the intermediate phase crystal and polarity adjustment mechanism were analyzed in depth.Through the SEM and XRD analysis of the prepared film,it was confirmed that the crystallinity of the perovskite film was greatly improved.At the same time,through the impedance spectra analysis,it was found that the recombination resistance of the perovskite device was increased and the film quality was improved.Finally,the PCE of planarinvertedperovskitecellspreparedwiththestructure:ITO/PEDOT:PSS/CH₃NH₃PbI₃/PC₆₁BM/Bphen/Ag have reached 16.5%.?2?In the fourth chapter,we used the interface engineering and hybrid perovskite materials to improve the efficiency of perovskite solar cells.The modification of PEDOT:PSS/Perovskite interface with PbBr₂ pre-coating layer could improve the crystallinity of perovskite.A high-quality perovskite active layer is obtained.The surface and cross-section SEM of the perovskite film were characterized,and it was found that the crystal quality of the film was greatly improved.Through time-resolved transient PL spectrum analysis,it can be found that the hole extraction rate is improved and the exciton lifetime is longer.By space-charge-limited current analysis,it is found that the electronic defect state density is reduced,the interface passivation is achieved.It was also found that the Br element are uniform distribute in perovskite film through ion migration.Finally,the open circuit voltage and short-circuit current density of the device was increased,and a PCE of 17.38%was realized.