Results
Title

Stabilization of Highly Efficient and Stable Phase‐Pure FAPbI<sub>3</sub> Perovskite Solar Cells by Molecularly Tailored 2D‐Overlayers.

Authors

Liu, Yuhang; Akin, Seckin; Hinderhofer, Alexander; Eickemeyer, Felix T.; Zhu, Hongwei; Seo, Ji‐Youn; Zhang, Jiahuan; Schreiber, Frank; Zhang, Hong; Zakeeruddin, Shaik M.; Hagfeldt, Anders; Dar, M. Ibrahim; Grätzel, Michael

Abstract

As a result of their attractive optoelectronic properties, metal halide APbI3 perovskites employing formamidinium (FA+) as the A cation are the focus of research. The superior chemical and thermal stability of FA+ cations makes α‐FAPbI3 more suitable for solar‐cell applications than methylammonium lead iodide (MAPbI3). However, its spontaneous conversion into the yellow non‐perovskite phase (δ‐FAPbI3) under ambient conditions poses a serious challenge for practical applications. Herein, we report on the stabilization of the desired α‐FAPbI3 perovskite phase by protecting it with a two‐dimensional (2D) IBA2FAPb2I7 (IBA=iso‐butylammonium overlayer, formed via stepwise annealing. The α‐FAPbI3/IBA2FAPb2I7 based perovskite solar cell (PSC) reached a high power conversion efficiency (PCE) of close to 23 %. In addition, it showed excellent operational stability, retaining around 85 % of its initial efficiency under severe combined heat and light stress, that is, simultaneous exposure with maximum power tracking to full simulated sunlight at 80 °C over 500 h.

Subjects

SOLAR cells; PEROVSKITE; SILICON solar cells; LEAD iodide; METAL halides; THERMAL stability; CHEMICAL stability; MAXIMUM power point trackers

Publication

Angewandte Chemie, 2020, Vol 132, Issue 36, p15818

ISSN

0044-8249

Publication type

Academic Journal

DOI

10.1002/ange.202005211