Fabrication Of Efficient And Stable Perovskite Solar Cell Devices By Interface Engineerin

In recent years,the contradiction between resources and the environment has become increasingly acute with the development of economy and science and technology.How to balance resource consumption and environmental pollution has become an urgent problem for many countries.Therefore,perovskite solar cells（PSCs）came into being.As a photovoltaic clean energy,the commercial application of PSCs needs to accept the dual test of photoelectric conversion efficiency（PCE）and stability,which requires continuous research and optimization of PSCs,so that they can be commercially applied to solve the contradiction between resources and the environment.In this paper,the defects in PSCs devices are mainly studied to improve the photoelectric conversion efficiency and stability of PSCs devices by selecting and optimizing the preparation conditions of the devices and the defect passivation of the upper and lower interfaces of the perovskite layer.The specific research content and results are as follows:（1）The preparation conditions of the electron transport layer and the perovskite layer were optimized.In this paper,the following conclusions were obtained by adjusting the thickness of the electron transport layer and the preparation environment of the perovskite layer:5 drops（150μL）of precursor solution should be selected to achieve the appropriate film thickness for the preparation of the electron transport layer at room temperature of 25°C.The preparation of perovskite layer film should be carried out in a 30%RH humidity environment to achieve a better film-forming effect.（2）Phenethyl iodide（PEAI）was used to passivate the perovskite layer interface.After screening and optimization of experimental conditions,PEAI with a concentration of 20 m M as the passivator,and determined the annealing temperature to be 110°C.Subsequently,the performance and stability of the device under different annealing methods were characterized.The results show that PEAI itself acts as a passivator without annealing to obtain the highest efficiency of 21.45%,and the passivation of the perovskite layer by forming two-dimensional（PEA）₂Pb I₄ perovskite in the annealed state significantly improves the stability of PSCs devices.（3）The lower interface of the perovskite layer was passivated by using MgCl₂+MgI₂.The passivated device has good conductivity,negligible hysteresis,low defect density,and good inhibition effect on interfacial charge extraction and non-radiative recombination.Finally,the PSCs devices passivated by MgCl₂+MgI₂ maintained 90%initial stability for 1000 h in air with40%humidity,and obtained an efficiency of 22.41%.