Abstract
Defects locating within grain boundaries or on the film surface, especially organic cation vacancies and iodine vacancies make the fabrication of perovskite solar cells (PSCs) with superior performance a challenge. Organic ammonium iodide is a promising candidate and has been frequently used to passivate these defects by forming two-dimensional (2D) perovskite. In this work, it is found that the chain length of organic ammonium iodide is a crucial factor on the defect passivation effect. Compared to butylammonium iodide (BAI), hexylammonium iodide (HAI) derived 2D perovskite is more efficient in decreasing interfacial defects, resulting in a notably enhanced photoluminescence lifetime and a more suppressed interfacial charge recombination process. As a consequence, the ultimate power conversion efficiency (PCE) has reached 20.62% (3D+HAI) as compared to 18.83% (3D). Moreover, the long-term durability of the corresponding PSCs against humidity and heat is simultaneously improved. This work once again demonstrates that 2D/3D structure is promising for further improving the PCE and stability of PSCs.
Funding Information
  • Ministry of Education of the People's Republic of China (DUT18LK48, DUT18ZD208)
  • National Natural Science Foundation of China (51605079, 51773025, 51872036)

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