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Nano Research

Article Title

Polymer assisted deposition of high-quality CsPbI2Br film with enhanced film thickness and stability

Authors

Jing Wei, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, Experimental Center of Advanced Materials School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China State Key Laboratory of Information Photonics and Optical Communications School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
Xi Wang, State Key Laboratory of Information Photonics and Optical Communications School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
Xiangyu Sun, State Key Laboratory of Information Photonics and Optical Communications School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
Zhaofeng Yang, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, Experimental Center of Advanced Materials School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China
Iwan Moreels, Department of Chemistry, Ghent University, 9000 Gent, Belgium
Kun Xu, State Key Laboratory of Information Photonics and Optical Communications School of Science, Beijing University of Posts and Telecommunications, Beijing 100876, China
Hongbo Li, Beijing Key Laboratory of Construction-Tailorable Advanced Functional Materials and Green Applications, Experimental Center of Advanced Materials School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081, China

Keywords

solar cell, perovskites, polymer, CsPbI2Br

Abstract

Inorganic halide perovskites such as cesium lead iodide (CsPbI3) have drawn tremendous attention, as their tunable band gaps are desirable for solar cells as well as light emitting diodes. However, due to their low Goldschmidt tolerance factor, the cubic phase of bulk CsPbX3—the variant with desirable band gap—is not stable in ambient, especially in humid air. Besides, the low solubility of CsX in precursor makes it difficult to control the film thickness and morphology of CsPbX3, which becomes another obstacle for the practical application of inorganic perovskite. Here, we report a polymer assisted deposition of high-quality CsPbI2Br film by spin-coating a polymer-blended CsPbI2Br precursor. The long-chained polymer increases the viscosity of the solution, which enables us to achieve a ca. 700-nm thick film with a low solution concentration of CsPbI2Br. Moreover, the polymer network helps to regulate the crystallization process and provides more crystallization sites for perovskite film, reducing grain size and thus improving the film coverage. Perovskite solar cells with the polymer network exhibit improved efficiency and reproducibility (0.72% standard deviation). Moreover, the device demonstrates excellent robustness against moisture and oxygen, and maintains 90% of its initial power conversion efficiency (PCEs) after aging 4 months in ambient conditions. The conception of polymer incorporation into inorganic perovskite films paves a way to further increase the performance, stability and reproducibility of inorganic perovskite devices.

Graphical Abstract

Publisher

Tsinghua University Press

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