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Nature Photonics (2026)
Hybrid two-step deposition offers a scalable route for fabricating metal halide perovskites in tandem architectures, particularly for achieving excellent conformality on textured substrates. However, using this approach for ultrawide-bandgap perovskites (>1.85 eV) remains a fundamental challenge, due to issues of incomplete conversion and inhomogeneous crystallization. Here we reveal that the bromine/iodine (Br/I) ratio critically governs the crystallinity of the evaporated inorganic framework (IOF), which plays a key role in the halide distribution and phase quality of the perovskite film during the following hybrid conversion process. In situ grazing incidence wide-angle X-ray scattering indicates that high Br content induces a low-crystallinity IOF and enables uniform and complete incorporation of organic cations. As a result, the high Br IOF enhances photoluminescence quantum yield in the final perovskite film from 0.28% to 1.14% and enables more homogeneous halide distribution. The resulting 1.88-eV perovskite achieves a power conversion efficiency of 17.13% in single-junction devices. When further integrated as the top subcell in monolithic perovskite/perovskite/silicon triple-junction solar cells, the triple-junction device delivers a maximum efficiency of 28.71% over an active area of 1 cm2 (certified 27.53%). We expect our findings to pave the way for the fabrication of ultrawide-bandgap perovskites and to contribute to continued improvements in triple-junction solar cells.
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The data that support the findings of this study are available from the corresponding authors. Source data are provided with this paper.
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Y.H. acknowledges support from the MOE Tier 1 grant (25-0182-A0001-0), the Ministry of Education (Singapore). Authors of this Article are affiliated with the Solar Energy Research Institute of Singapore (SERIS), a research institute at the National University of Singapore (NUS). SERIS is supported by the National University of Singapore (NUS), the National Research Foundation Singapore (NRF), the Energy Market Authority of Singapore (EMA) and the Singapore Economic Development Board (EDB). S.L. acknowledges funding from the National Natural Science Foundation of China (grant no. 52502220). We acknowledge that the computational work involved in this research was fully supported by the NUS IT Research Computing group under grant NUSREC-HPC-00001. J.A.S. acknowledges financial support from the Australian Research Council (DE230100173). We thank the staff of the BL11 NCD-SWEET beamline at ALBA Synchrotron for their assistance in recording the GIWAXS data. We acknowledge the use of the XAS beamline at the Australian Synchrotron, part of ANSTO, and travel funding provided by the International Synchrotron Access Program (ISAP) managed by the Australian Synchrotron and funded by the Australian Government. This research used the TEM resources and facilities at A*STAR Institute of Materials Research and Engineering (IMRE).
These authors contributed equally: Yu-Duan Wang, Jingcong Hu, Ran Luo, Qilin Zhou, Shunchang Liu.
Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore, Singapore
Yu-Duan Wang, Jingcong Hu, Ran Luo, Qilin Zhou, Tao Wang, Xiuxiu Niu, Yuxin Yao, Zhenrong Jia, Xinyu Zhang, Ezra Alvianto, Xiao Guo, Zijing Dong, Xi Wang, Jinxi Chen, Yuhui Jiang, Chao Luo, Zihao Zhu, Nengxu Li, Xinyi Du & Yi Hou
Solar Energy Research Institute of Singapore, National University of Singapore, Singapore, Singapore
Yu-Duan Wang, Jingcong Hu, Ran Luo, Qilin Zhou, Tao Wang, Xiuxiu Niu, Yuxin Yao, Ling Kai Lee, Zhenrong Jia, Xinyu Zhang, Ezra Alvianto, Xiao Guo, Zijing Dong, Xi Wang, Jinxi Chen, Yuhui Jiang, Zihao Zhu, Nengxu Li, Xinyi Du & Yi Hou
Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore
Jingcong Hu
National Key Laboratory of Electronic Films and Integrated Devices, School of Physics, University of Electronic Science and Technology of China, Chengdu, China
Shunchang Liu
Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
Julian A. Steele
School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland, Australia
Julian A. Steele & Yi-Hsun Chen
State Key Laboratory of Bioinspired Interfacial Materials Science, Institute of Functional Nano and Soft Materials, Soochow University, Suzhou, China
Rui Zhang
Photophysics and OptoElectronics, Zernike Institute for Advanced Materials, University of Groningen, Groningen, the Netherlands
Guiseppe Portale
CD-SWEET beamline ALBA Synchrotron Light Source, Cerdanyola del Vallès, Spain
Eduardo Solano
Institute of Materials Research and Engineering, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
Ming Lin
School of Chemical Engineering, The University of Queensland, Brisbane, Queensland, Australia
Gordon Ochsner
College of Energy, Soochow Institute for Energy and Materials Innovations, Jiangsu Provincial Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies, Soochow University, Suzhou, China
Wan-Jian Yin
Hefei National Laboratory, Hefei, China
Wan-Jian Yin
State Key Laboratory of PV Science and Technology, Trina Solar, Changzhou, China
Xueling Zhang, Yifeng Chen & Jifan Gao
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Y.-D.W., S.L. and Y.H. conceived the idea and designed the experiments. Y.H. supervised the project. Y.-D.W. fabricated the ultrawide-bandgap perovskite solar cells, Y.-D.W., S.L., Q.Z., T.W. and Y.Y. fabricated the dual-junction and triple-junction tandem solar cells. J.H. and M.L. performed STEM. R.L. and W.-J. Y. performed the DFT calculations. J.A.S., R.Z., G.P. and E.S. conducted the GIWAXS measurements. J.A.S., Y.-H.C and G.O. performed the XAS. Z.D. and X.G. assisted with confocal PL. E.A. and N.L. assisted with the metal halide evaporation. Xueling Zhang, Y.C. and J.G. contributed to the Si solar cells. X.N. and L.K.L. performed the PL measurements. Xinyu Zhang, Z.J. and Y.J. performed EQE measurements. X.W. and J.C. performed SEM. C.L., Z.Z. and X.D. assisted with characterizations for the devices. Y.-D.W., J.H., R.L., Q.Z., S.L. and Y.H. analysed the data and wrote the manuscript. All authors read and commented on the manuscript.
Correspondence to Shunchang Liu or Yi Hou.
The authors declare no competing interests.
Nature Photonics thanks Weijun Ke, Anita Ho-Baillie, Christian Wolff and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
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Wang, YD., Hu, J., Luo, R. et al. Crystallinity-guided hybrid conversion for efficient ultrawide-bandgap perovskites in triple-junction solar cells. Nat. Photon. (2026). https://doi.org/10.1038/s41566-026-01922-2
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