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Organic‐Salt‐Assisted Crystal Growth and Orientation of Quasi‐2D Ruddlesden–Popper Perovskites for Solar Cells with Efficiency over 19%
Author(s) -
Lai Hongtao,
Lu Di,
Xu Zhiyuan,
Zheng Nan,
Xie Zengqi,
Liu Yongsheng
Publication year - 2020
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202001470
Subject(s) - materials science , energy conversion efficiency , formamidinium , photocurrent , perovskite (structure) , iodide , thermal stability , salt (chemistry) , photovoltaic system , crystal growth , band gap , crystal (programming language) , chemical engineering , inorganic chemistry , optoelectronics , crystallography , organic chemistry , chemistry , ecology , programming language , computer science , engineering , biology
Quasi‐2D Ruddlesden–Popper (RP) perovskite solar cells (PSCs) have drawn significant attention due to their appealing environmental stability compared to their 3D counterparts. However, the relatively low power conversion efficiency (PCE) greatly limits their applications. Here, high photovoltaic performance is demonstrated for quasi‐2D RP PSCs using 2‐thiophenemethylammonium as spacer with nominal n ‐value of 5, which is based on the stoichiometry of the precursors. The incorporation of formamidinium (FA) in quasi‐2D RP perovskites reduces the bandgap and improves the light absorption ability, resulting in enlarged photocurrent and an increased PCE of 16.18%, which is higher than that of reported analogous methylammonium (MA)‐based quasi‐2D PSC (≈15%). A record high PCE of 19.06% is further demonstrated by using an organic salt, namely, 4‐(trifluoromethyl)benzylammonium iodide, assisted crystal growth (OACG) technique, which can induce the crystal growth and orientation, tune the surface energy levels, and suppress the charge recombination losses. More importantly, the devices based on OACG‐processed quasi‐2D RP perovskites show remarkable environmental stability and thermal stability, for example, the PCE retaining ≈96% of its initial value after storage at 80 °C for 576 h, while only ≈37% of the original efficiency left for FAPbI 3 ‐based 3D PSCs.