Mixed 3D–2D Passivation Treatment for Mixed‐Cation Lead Mixed‐Halide Perovskite Solar Cells for Higher Efficiency and Better Stability |
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Authors: | Yongyoon Cho Arman Mahboubi Soufiani Jae Sung Yun Jincheol Kim Da Seul Lee Jan Seidel Xiaofan Deng Martin A. Green Shujuan Huang Anita W. Y. Ho‐Baillie |
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Affiliation: | 1. Australian Centre for Advanced Photovoltaics (ACAP), School of Photovoltaic and Renewable and Engineering, University of New South Wales, Sydney, Australia;2. School of Materials Science and Engineering, University of New South Wales, Sydney, Australia |
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Abstract: | Layered low‐dimensional perovskite structures employing bulky organic ammonium cations have shown significant improvement on stability but poorer performance generally compared to their 3D counterparts. Here, a mixed passivation (MP) treatment is reported that uses a mixture of bulky organic ammonium iodide (iso‐butylammonium iodide, iBAI) and formammidinium iodide (FAI), enhancing both power conversion efficiency and stability. Through a combination of inactivation of the interfacial trap sites, characterized by photoluminescence measurement, and formation of an interfacial energetic barrier by which ionic transport is reduced, demonstrated by Kelvin probe force microscopy, MP treatment of the perovskite/hole transport layer interface significantly suppresses photocurrent hysteresis. Using this MP treatment, the champion mixed‐halide perovskite cell achieves a reverse scan and stabilized power conversion efficiency of 21.7%. Without encapsulation, the devices show excellent moisture stability, sustaining over 87% of the original performance after 38 d storage in ambient environment under 75 ± 20% relative humidity. This work shows that FAI/ i BAI, is a new and promising material combination for passivating perovskite/selective‐contact interfaces. |
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Keywords: | 2D perovskite mixed‐cation perovskite solar cells passivation stability |
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