Pan Xu group of Hefei Research Institute of Chinese Academy of Sciences and its collaborators have made new progress in the research of efficient and stable 2D / 3D perovskite solar cells

Recently, pan Xu group of Applied Technology Research Institute of Hefei Institute of material science, Chinese Academy of Sciences and Dai Songyuan group of North China Electric Power University have made new progress in the preparation of efficient and stable 2D / 3D perovskite solar cells Relevant research results were published in advanced functional materials (DOI: 10.1002 / ADFM 201807565) under the title of "introduction of hydrobic ammonium salts with halogenated functional groups for high-efficiency and stable 2D / 3D perovskite solar cells" In the past few years, the research of organic-inorganic metal halide perovskite solar cells has made rapid development, and the certified photoelectric conversion efficiency has reached 23.7% 2D perovskite materials have attracted more and more attention because of their higher stability compared with 3D perovskite However, the hydrophobicity of ammonium salt has a great influence on the long-term humidity stability of the battery Therefore, it is a challenge to design a new type of efficient and stable 2D / 3D perovskite solar cell by introducing a suitable size of hydrophobic ammonium salt In view of the above problems, Dr Liu Guozhen of Pan Xu's research group introduced short chain ammonium salt containing halogen functional group to effectively increase the hydrophobic characteristics of ammonium salt, improve the efficiency of the battery, further improve the stability of the device, and finally obtain efficient and stable 2D / 3D perovskite solar cells In caesium / MCM mixed cation 3D perovskite materials, 2-chloroethylamine hydrochloride (CEA) and 2-bromoethylamine hydrobromate (BEA) were introduced to form 2D / 3D perovskite structure respectively The influence of CEA and bea on the photoelectric properties and stability of perovskite films was studied Finally, high-quality perovskite films with high crystallinity, flat and compact morphology were obtained When 5% 2-chloroethylamine hydrochloride is introduced, the highest photoelectric conversion efficiency of the cell is 20.08%, which is significantly higher than that of 3D perovskite device (18.97%) The introduction of ammonium salt containing halogen functional group greatly increased the humidity stability of the battery The device aged for 2400 hours at 50 ± 5% relative humidity, the 2D / 3D perovskite device still maintained 92% of the initial efficiency, while the 3D perovskite device only maintained 60% of the initial efficiency In addition, 2D / 3D perovskite devices show excellent thermal stability and UV light stability.