Intermolecular Exchange Boosts Efficiency of Air‐Stable, Carbon‐Based All‐Inorganic Planar CsPbIBr2 Perovskite Solar Cells to Over 9

Among all inorganic halide perovskite photovoltaic materials, CsPbIBr2 exhibits the most balanced features in terms of bandgap and stability. However, the poor quality of solution‐processed CsPbIBr2 films impedes further optimization of cells performance. Herein, a facile intermolecular exchange str...

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Bibliographic Details
Published in:Advanced energy materials 2018-10, Vol.8 (30), p.n/a
Main Authors: Zhu, Weidong, Zhang, Qianni, Chen, Dazheng, Zhang, Zeyang, Lin, Zhenhua, Chang, Jingjing, Zhang, Jincheng, Zhang, Chunfu, Hao, Yue
Format: Article
Language:English
Subjects:
Carbon
CsPbIBr2
Efficiency
Exchanging
Grain boundaries
Humidity
inorganic perovskites
intermolecular exchange
Perovskites
Photovoltaic cells
Relative humidity
Solar cells
Stability
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Summary:Among all inorganic halide perovskite photovoltaic materials, CsPbIBr2 exhibits the most balanced features in terms of bandgap and stability. However, the poor quality of solution‐processed CsPbIBr2 films impedes further optimization of cells performance. Herein, a facile intermolecular exchange strategy for CsPbIBr2 film is demonstrated, wherein an optimized methanol solution of CsI is spin‐coated on CsPbIBr2 precursor film in conventional one‐step solution route. It surprisingly produces full‐coverage and pure‐phase CsPbIBr2 films featured with average grain size of ≈0.65 µm, few grain boundaries, high crystallinity, preferable (100) orientation, stoichiometric composition along with favorable electronic structures for effective dissociation and transfer of carriers. Hence, the cost‐effective, carbon‐based all‐inorganic planar perovskite solar cells based on them, yield an optimized efficiency of 9.16% with a stabilized value of 8.46% in ambient air conditions that highlight a particularly superb open‐circuit voltage of 1.245 V, all of which represent the highest values reported in pure CsPbIBr2 based cells so far. Moreover, the optimized cell without encapsulation shows excellent long‐term stability because it can retain 90% over 60 days and 97% over 7 days of its initial efficiency, when is stored controllably in ≈45% relative humidity at 25 or 85 °C at zero humidity, respectively. A carbon‐based all‐inorganic planar CsPbIBr2 solar cell with a record efficiency of 9.16%, an extremely high open‐circuit voltage of 1.245 V, and excellent long‐term stability is achieved by a facile intermolecular exchange strategy. Its impressive performance mainly derives from the desirable features of CsPbIBr2 film including full coverage, high crystallinity, preferable (100) orientation, and stoichiometric composition along with favorable electronic structure.
ISSN:1614-6832
1614-6840
DOI:10.1002/aenm.201802080