Effect Of Grain Boundary Passivation On Device Performance Of Perovskite Solar Cells

Perovskite solar cells have been a research hotspot in the field of photoelectric conversion in recent years because of their advantages such as low exciton binding energy,fast carrier diffusion rate,long diffusion distance,high absorption coefficient and wide absorption window.After nearly ten years of rapid development,the energy conversion efficiency of laboratory batteries has increased rapidly to 25.5%.Perovskite membrane crystallization quality,and the degree of contact between the transport layer are affecting the device performance,in addition,during the preparation of perovskite battery components due to the influence of annealing time,crystallization rate and other factors,and interface within the perovskite inevitably produces a large number of defects,which affects the device efficiency and stability,and greatly restricted the development of the perovskite solar cells.In order to solve the above problems,researchers from various countries put forward a large number of feasible schemes.Research,this article is a few questions to plane perovskite of organic and inorganic heterojunction solar cells as the object,discusses the perovskite defects and defects in solar cells influence on solar cells,through the modified perovskite membrane crystallization process,methods of adding passivator,obtained the good performance of perovskite solar cells.The main work of this paper is as follows:First of all,we based on the original FAPbI₃ perovskite optimized experiment on the solar cell device,through the system of changing the ratio of electron transport layer of the precursor solution,preparation of annealing time perovskite active layer control and hole transport layer of the preparation of the spin rate,from the point of view of the three improved the experimental conditions,successfully improve the device performance,improve the photoelectric conversion efficiency,in order to further the passivation provides a good experimental premise,and found in annealing time change of the perovskite phase transition phenomenon,in the research of the perovskite structure provides a new direction.Secondly,we significantly improved the crystallinity by introducing Cs⁺ions and MABr to passivate the FAPBI₃-based perovskite film and using an ion exchange method to induce the crystallization process of the mesophase.Due to the small binding energy and low sublimation point,MACl leaves the perovskite film in the form of steam during thermal annealing,and the surface porosity of the film is also increased.In addition,the introduced Cs+ions fill the void left by the MACL vapor,passivate the surface of the perovskite film and improve the crystallinity of the film.The perovskite solar cell devices with the best photovoltaic performance were prepared by systematically changing the effects of different amounts of Ma Br and Cs Cl complete reactions in the precursor solution and on the crystallization of the perovskite film.The device with 12 mg MABr has the best efficiency,and the photoelectric conversion efficiency is 21.57%.Due to various charging defects on the surface and grain boundary of perovskite film,the device performance and stability of perovskite solar cells will be greatly affected.By doping quantitative ZnS/CdS quantum dots in the perovskite absorbent layer as passivating agent and relying on the hydrophobic advantage of ZnS/CdS quantum dots,the roughness and thickness of the perovskite film are improved in morphology,thus enhancing the photoelectric properties of the film.It is found that the LUMO level of the passivated perovskite film decreases from-3.75 e V to-3.85 e V,which reduces the potential barrier,facilitates the rapid transmission of electrons,reduces the loss of the built in potential,and significantly enhances the open circuit voltage of the perovskite solar cell.At the same time,the addition of ZnS/CdS quantum dots improves the hydrophobicity of the device,which makes the stability significantly improved.