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Stabilization of Highly Efficient and Stable Phase‐Pure FAPbI 3 Perovskite Solar Cells by Molecularly Tailored 2D‐Overlayers
Author(s) -
Liu Yuhang,
Akin Seckin,
Hinderhofer Alexander,
Eickemeyer Felix T.,
Zhu Hongwei,
Seo JiYoun,
Zhang Jiahuan,
Schreiber Frank,
Zhang Hong,
Zakeeruddin Shaik M.,
Hagfeldt Anders,
Dar M. Ibrahim,
Grätzel Michael
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202005211
Subject(s) - formamidinium , overlayer , energy conversion efficiency , perovskite (structure) , iodide , materials science , perovskite solar cell , halide , thermal stability , solar cell , chemical engineering , optoelectronics , annealing (glass) , chemistry , nanotechnology , inorganic chemistry , crystallography , engineering , composite material
As a result of their attractive optoelectronic properties, metal halide APbI 3 perovskites employing formamidinium (FA + ) as the A cation are the focus of research. The superior chemical and thermal stability of FA + cations makes α‐FAPbI 3 more suitable for solar‐cell applications than methylammonium lead iodide (MAPbI 3 ). However, its spontaneous conversion into the yellow non‐perovskite phase ( δ ‐FAPbI 3 ) under ambient conditions poses a serious challenge for practical applications. Herein, we report on the stabilization of the desired α‐FAPbI 3 perovskite phase by protecting it with a two‐dimensional (2D) IBA 2 FAPb 2 I 7 (IBA= iso ‐butylammonium overlayer, formed via stepwise annealing. The α‐FAPbI 3 /IBA 2 FAPb 2 I 7 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.