Performance Study Of Additives And Passivators In Perovskite Solar Cells

Recently,due to theirs advantages such as high carrier mobility,large light absorption coefficient,long carrier lifetime,long carrier diffusion length,and low cost,the organic-inorganic metal perovskite materials have been attracted widespread attention in the field of solar cells.Although the perovskite solar cell?PSC?has made rapid development,there are still many issues to be further investigated in the process of promoting the industrialization of PSC.Among them,the quality of the perovskite films is a decisive factor that affects the photoelectric conversion efficiency and environmental stability of the PSC,so the preparation of high-quality perovskite films with controlled morphology and uniform coverage is particularly important to improve the efficiency and stability of PSC.In this thesis,high-quality perovskite films are prepared by using simple and efficient additives and passivators.By characterizing the basic properties of the films,their effects on the photoelectric conversion efficiency and stability of the PSC are further investigated.The main contents of this thesis are as follows:Chapter One: The development history,structure,working principle and the research progresses of PSC are briefly described,and then the content and significance of the research in this thesis are illustrated.Chapter Two: The reagents,instruments and characterization methods in the experiment are summarized.Chapter Three: An ionic-liquid additive of methylammonium acetate?MAAc?is introduced in the lead iodide?Pb I₂?precursor solution to enhance the morphology and photovoltaic performances of perovskite films through the two-step spin-coating method.In this part,the effect of MAAc on the formation of perovskite films is studied.The photoelectric conversion efficiency of PSC with MAAc is 17.07%,which is higher than that of the PSC without MAAc?14.54%?.Chapter Four: Magnesium acetate?Mg Ac₂?additive is introduced into the Pb I₂ precursor solution to prepare perovskite films by the two-step spincoating method.The quality of the perovskite films is improved by the synergistic effect of Mg²⁺ and Ac–.In this part,the mechanism on Mg Ac₂ improving the performance of perovskite films is studied,and the PSC containing Mg Ac₂ has better stability and higher photoelectric conversion efficiency?17.76%?than that of the initial PSC.Chapter Five: Perovskite surface is treated with hydrophobic molecular thiosalicylic acid?TSA?to enhance stability of the PSC by passivating defects.In this part,the interaction between TSA molecules and the perovskite surface is explained.After TSA passivation,the photoelectric conversion efficiency of the PSC is increased to 18.09%,and the stability is greatly improved.When stored in the air with a relative humidity of 30% for15 days,the initial efficiency can maintain at 89.98%,while that of the initial PSC only maintain at 78.02%.Chapter Six: The research works of this thesis are summarized and the future research direction is prospected.In this thesis,the morphology of the films is improved by using MAAc or Mg Ac₂ additive,and the photoelectric conversion efficiency of the PSC is improved.The stability of the PSC is also improved by using TSA passivator.These results will provide a reliable theoretical basis for further improving the performance of PSC.