Abstract
Wide-bandgap (WBG) perovskite solar cells (PSCs) have emerged as promising candidates for tandem applications, despite potential instability induced by halogen components. Formamidinium-cesium (FACs)-based perovskites represent as an intrinsically stable WBG system due to their low bromine-to-lead ratio and the absence of thermally unstable methylammonium. However, the performance of FACs-based WBG perovskites is highly dependent on achieving precise control over the formation dynamics. Here, we employ in-situ characterization to reveal that the key to this control lies in the evolution of the intermediate phase and propose a pathway-priming strategy. By strategically guiding the early formation of the CsPbX3 intermediate phases, the strategy in turn templates and accelerates the subsequent transformation to the desired α-phase. The primed pathway yields a more uniform and complete phase transition, leading to enhanced film homogeneity. As a result, we demonstrate highly efficient 1.67 eV WBG PSCs with an efficiency exceeding 23%, along with excellent long-term operating stability maintaining 90% initial performance for 800 hours under continuous light stress. Furthermore, semitransparent WBG PSC achieve efficiencies of 20.91% (0.1 cm2) and 19.67% (1.0 cm2), corresponding to a four-terminal perovskite/silicon tandem solar cells with an efficiency of 31.04% (1.0 cm2), highlighting their potential for high-performance tandem photovoltaics.
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Acknowledgements
This work was supported by the National Natural Science Foundation of China (52576215), National Key Research and Development Program of China (2025YFB4007600), Guangdong Basic and Applied Basic Research Foundation (2025A1515011993, 2024B1515120043), Department of Science and Technology of Guangdong Province (2025A0505080001), Guangdong Grants (2021ZT09C064, 2021QN02L138), Guangdong Provincial University Science and Technology Program (2025KTSCX114), and High level of special funds (G03034K001). The authors thank the technical support from the SUSTech Core Research Facilities. The authors thank the staff from Shanghai Synchrotron Radiation Facility (SSRF) at BL02U2.
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L.Q., W.L. and P.H. supervised this work. N.H. conceived the ideas and designed the experiments. J.F. provided the GIWAXS measurements. X.W. participated in the fabrication of the semi-transparent PSCs. S.H. and S.L. conducted the GIXRD measurements. G.X. and L.G. provided valuable suggestions for the FTIR and NMR tests. H.P. and X.L. provided valuable suggestions for the experiments. X.Z., F.L., Z.Y. and P.Z. participated in the fabrication of the 4 T perovskite/Si TSCs. N.H. wrote the manuscript, and all authors reviewed the paper.
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Huang, N., Fang, J., Wang, X. et al. Pathway-priming of intermediate phases in FACs-based wide-bandgap perovskites for Si tandem solar cells. Nat Commun (2026). https://doi.org/10.1038/s41467-026-72094-4
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DOI: https://doi.org/10.1038/s41467-026-72094-4
