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Functionalization of perovskite thin films with moisture-tolerant molecules

Abstract

Organic–inorganic hybrid perovskites are particularly suited as light-harvesting materials in photovoltaic devices. The power conversion efficiency of perovskite solar cells has reached certified values of over 20% in just a few years. However, one of the major hindrances for application of these materials in real-world devices is the performance degradation in humid conditions, leading to a rapid loss of photovoltaic response. Here, we demonstrate that hydrophobic tertiary and quaternary alkyl ammonium cations can be successfully assembled on the perovskite surface as efficient water-resisting layers via a facile surface functionalization technique. Such layers can protect the perovskite film under high relative humidity (90 ± 5%) over 30 days. More importantly, devices based on such films can retain the photovoltaic capacities of bulk perovskites, with power conversion efficiencies over 15%. Improving the humidity tolerance of perovskite materials is a necessary step towards large-scale production of high-performance perovskite-based devices under ambient humidity.

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Figure 1: Water molecule adsorption on perovskite surfaces.
Figure 2: Water-resisting layer assembly and photovoltaic performance.
Figure 3: Light-accelerated degradation and full device stability studies.
Figure 4: Moisture tolerance of functionalized perovskite crystals.
Figure 5: Modelling atomic structures of functionalized perovskite surfaces.

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Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (21373083) and Fundamental Research Funds for the Central Universities (WD1313009). This research was undertaken in the NCI National Facility in Canberra, Australia, which is supported by the Australian Commonwealth Government.

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H.G.Y. and H.J.Z. conceived the project and contributed to the design of the experiments and analysis of the data. S.Y. performed the material preparation, device fabrication and characterizations. Y.W. and P.L. conducted DFT calculations and wrote part of the paper (calculations). Y.-B.C. performed data analyses of photovoltaic properties. S.Y. prepared the manuscript with the help of H.G.Y. and H.J.Z. All the authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Hui Jun Zhao or Hua Gui Yang.

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The authors declare no competing financial interests.

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Supplementary Information

Supplementary Figures 1-16, Supplementary Tables 1-3, Supplementary References. (PDF 1678 kb)

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Yang, S., Wang, Y., Liu, P. et al. Functionalization of perovskite thin films with moisture-tolerant molecules. Nat Energy 1, 15016 (2016). https://doi.org/10.1038/nenergy.2015.16

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