Abstract
Doping of perovskite semiconductors1 and passivation of their grain boundaries2 remain challenging but essential for advancing high-efficiency perovskite solar cells. Particularly, it is crucial to build perovskite/indium tin oxide (ITO) Schottky contact based inverted devices without predepositing a layer of hole-transport material3,4,5. Here we report a dimethylacridine-based molecular doping process used to construct a well-matched p-perovskite/ITO contact, along with all-round passivation of grain boundaries, achieving a certified power conversion efficiency (PCE) of 25.39%. The molecules are shown to be extruded from the precursor solution to the grain boundaries and the bottom of the film surface in the chlorobenzene-quenched crystallization process, which we call a molecule-extrusion process. The core coordination complex between the deprotonated phosphonic acid group of the molecule and lead polyiodide of perovskite is responsible for both mechanical absorption and electronic charge transfer, and leads to p-type doping of the perovskite film. We created an efficient device with a PCE of 25.86% (reverse scan) and that maintained 96.6% of initial PCE after 1,000 h of light soaking.
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All data are available in either the main text or supplementary materials, and are also available from the corresponding author on reasonable request.
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Acknowledgements
We thank W. Tian and S. Jin from the Dalian Institute of Chemical Physics (Chinese Academy of Sciences) for transient absorption testing and data analysis, H. He from the Department of Physics (SUSTech) for discussions on semiconductor physics and W. Lu and L. Chung from the Department of Chemistry (SUSTech) for discussions on coordination chemistry. The authors thank Core Research Facilities, Department of Materials Science and Engineering for characterizations, and the Center of Computational Science and Engineering of SUSTech for calculations. We also thank the National Natural Science Foundation of China (nos. U2001216 and 52273266), the Shenzhen Key Laboratory Project (no. ZDSYS201602261933302), the Guangdong Provincial Key Laboratory of Computational Science and Material Design (grant no. 2019B030301001) and the Shenzhen Science and Technology Innovation Committee (no. JCYJ20200109141412308).
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Z.H., Q.T. and Z.L. conceived the idea for the project. Z.H. directed and supervised the project. Q.T. fabricated and characterized the devices. Z.L. designed and synthesized molecules and carried out NMR and FTIR characterization. G.L. performed DFT calculations. X.Z. conducted AFM-IR characterization. B.C. and T.C. carried out DLTS measurements and data analysis. G.C. and H.Y. performed UPS characterization. H.G. conducted SEM and energy-dispersive X-ray spectroscopy. G.M. conducted Hall testing. D.H. performed pH and other electrochemical testing. J.W. and J.X. participated in characterization of other properties. Z.H., Z.L. and Q.T. analysed all data and wrote the manuscript. All authors discussed the results and commented on the manuscript.
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A Chinese patent application (no. 2023100349666), submitted by SUSTech, covers the AcPA series molecule-based molecule-extrusion process for the fabrication of HTL-free perovskite solar cells.
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Nature thanks Xiaoming Wang, Masatoshi Yanagida and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.
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Tan, Q., Li, Z., Luo, G. et al. Inverted perovskite solar cells using dimethylacridine-based dopants. Nature 620, 545–551 (2023). https://doi.org/10.1038/s41586-023-06207-0
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DOI: https://doi.org/10.1038/s41586-023-06207-0
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