• Kim, Jinhyun
• Gil, Bumjin

Abstract

<jats:p>As for the commonly used formamidinum lead iodide (FAPbI<jats:sub>3</jats:sub>) perovskite, adding small amount of larger organic cations is a viable strategy to overcome its instability caused by formamidinium (FA) or iodide (I). Herein, FAPbI<jats:sub>3</jats:sub> perovskite is modified by addition of quaternary cation phenyltrimethylammonium (PTMA), which forms 2D perovskite phase. With the presence of PTMA cations and small‐sized Br anions, the local strain of perovskite layer is mitigated. Also, x‐ray analyses reveal that PTMA cations directs FAPbI<jats:sub>3</jats:sub> to have more vertically oriented structure, which aids the enhanced photocarrier generation and extraction. Defect analyses suggest that PTMABr alloying also greatly reduces the trap sites. Due to these combined effects, the PTMABr‐modified device results in the improved <jats:italic>V</jats:italic><jats:sub> <jats:italic>OC</jats:italic> </jats:sub> plus stability under 60 °C or 1 sun illumination, maintaining 80% of its initial efficiency after 1800 h and 1400 h, respectively.</jats:p><jats:p>This article is protected by copyright. All rights reserved.</jats:p>

Topics

• perovskite
• impedance spectroscopy
• phase
• extraction
• defect