Mixed Cation FAxPEA1–xPbI3 with Enhanced Phase and Ambient Stability toward High‐Performance Perovskite Solar Cells |
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| Authors: | Nan Li Zonglong Zhu Chu‐Chen Chueh Hongbin Liu Bo Peng Alessio Petrone Xiaosong Li Liduo Wang Alex K.‐Y. Jen |
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| Affiliation: | 1. Department of Materials Science & Engineering, University of Washington, Seattle, WA, USA;2. Key Lab of Organic Optoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing, China;3. Department of Chemistry, University of Washington, Seattle, WA, USA |
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| Abstract: | In this work, different from the commonly explored strategy of incorporating a smaller cation, MA+ and Cs+ into FAPbI3 lattice to improve efficiency and stability, it is revealed that the introduction of phenylethylammonium iodide (PEAI) into FAPbI3 perovksite to form mixed cation FAxPEA1–xPbI3 can effectively enhance both phase and ambient stability of FAPbI3 as well as the resulting performance of the derived devices. From our experimental and theoretical calculation results, it is proposed that the larger PEA cation is capable of assembling on both the lattice surface and grain boundaries to form quais‐3D perovskite structures. The surrounding of PEA+ ions at the crystal grain boundaries not only can serve as molecular locks to tighten FAPbI3 domains but also passivate the surface defects to improve both phase and moisture stablity. Consequently, a high‐performance (PCE:17.7%) and ambient stable FAPbI3 solar cell could be developed. |
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| Keywords: | ambient stability formamidinium lead iodide perovskite solar cells phase stability |
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