Abstract
Two-dimensional (2D) organic-inorganic perovskites have recently emerged as one of the most important thin-film solar cell materials owing to their excellent environmental stability. The remaining major pitfall is their relatively poor photovoltaic performance in contrast to 3D perovskites. In this work we demonstrate cesium cation (Cs) doped 2D (BA)(MA)PbI perovskite solar cells giving a power conversion efficiency (PCE) as high as 13.7%, the highest among the reported 2D devices, with excellent humidity resistance. The enhanced efficiency from 12.3% (without Cs) to 13.7% (with 5% Cs) is attributed to perfectly controlled crystal orientation, an increased grain size of the 2D planes, superior surface quality, reduced trap-state density, enhanced charge-carrier mobility and charge-transfer kinetics. Surprisingly, it is found that the Cs doping yields superior stability for the 2D perovskite solar cells when subjected to a high humidity environment without encapsulation. The device doped using 5% Cs degrades only ca. 10% after 1400 hours of exposure in 30% relative humidity (RH), and exhibits significantly improved stability under heating and high moisture environments. Our results provide an important step toward air-stable and fully printable low dimensional perovskites as a next-generation renewable energy source.
Original language | English (US) |
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Pages (from-to) | 2095-2102 |
Number of pages | 8 |
Journal | Energy Environ. Sci. |
Volume | 10 |
Issue number | 10 |
DOIs | |
State | Published - 2017 |
Bibliographical note
KAUST Repository Item: Exported on 2020-10-01Acknowledgements: This work was supported by the National Key Research project MOST (2016YFA0202400), the National Natural Science Foundation of China (61604092 and 61674098), the National University Research Fund (Grant No. GK261001009, GK201603107), the 111 Project (B14041), and the Chinese National 1000-talent-plan program (1110010341). CHESS is supported by the NSF award DMR-1332208.