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Nature Energy (2026)
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Monolithic perovskite/silicon tandem solar cells offer a promising pathway to surpass the efficiency limits of single-junction photovoltaics. However, their performance, stability and scalability are constrained by the recombination layer, which needs to simultaneously enable efficient charge recombination, high optical transparency and robust interfacial chemistry. Existing indium-containing transparent conductive oxides raise concerns regarding cost and sustainability, whereas silicon-based tunnel junctions suffer from parasitic optical losses. Here we show that titanium oxynitride (TiOxNy) can serve as a multifunctional, indium-free recombination layer that reconciles these competing requirements. Conductive TiOxNy enables efficient vertical carrier recombination, suppresses lateral leakage and provides anchoring sites for self-assembled monolayers (SAMs) via a tridentate binding configuration. As a result, we achieve power conversion efficiencies (PCEs) of 33.3% for 1.0-cm2 devices and 30.6% for industrial-size (207.87 cm2) tandems, with enhanced operational stability. Our results establish TiOxNy as a scalable and sustainable interconnection strategy for tandem photovoltaics.
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Vienna Ab initio Simulation Package (VASP) for the DFT calculations is available at https://www.vasp.at/.
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The work was financially supported by the National Natural Science Foundation of China (numbers 62174114, 62422512 and U24A2063), the National Key R&D Program of China (number 2022YFB4200203), the Key Project of Jiangsu Provincial Basic Research Plan (number BK20243031), the Department of Science and Technology of Jiangsu Province (number BE2022023) and the Research Grants Council of the Hong Kong Special Administrative Region, China (numbers PolyU 25300823 and PolyU 15300724). We acknowledge the Joint R&D Center of Suzhou National Laboratory, Kunshan GCL Optoelectronic Material Co., Ltd., and Soochow University.
These authors contributed equally: Fengxian Cao, Yao Li, Shibo Wang, Kin Long Wong.
College of Energy, Soochow University, Suzhou, China
Fengxian Cao, Yao Li, Shibo Wang, Bo Gao, Wenhao Li, Wei Shi, Kun Gao, Liu Yang, Bowen Yang & Xinbo Yang
Department of Applied Physics, Research Center for Organic Electronics, The Hong Kong Polytechnic University, Kowloon, China
Kin Long Wong & Jun Yin
Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory of Advanced Negative Carbon Technologies, Soochow University, Suzhou, China
Cao Yu & Xiaohong Zhang
Suzhou Maxwell Technologies Co. Ltd, Suzhou, China
Cao Yu, Shaofei Yang, Xi Chen & Jian Zhou
Department of Materials, University of Oxford, Oxford, UK
Xinya Niu & Ruy Sebastian Bonilla
Wuxi EliTe Solar Co. Ltd., Wuxi, China
Jianwei Yu, Yue Zhang, Yiliang Wu & Jun Zhu
Hangzhou Zhongneng Photoelectricity Technology Co. Ltd., Hangzhou, China
Wenzhen An, Shifeng Deng & Lei Shi
Hoffmann Institute of Advanced Materials, Shenzhen Polytechnic University, Shenzhen, China
Fei Wang & Hanlin Hu
Suzhou National Laboratory, Suzhou, China
Xiaohong Zhang & Xinbo Yang
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X.Y. conceived the idea, designed the overall experiments and led the project. X.Y. and F.C. wrote the paper. F.C., Y.L. and S.W. fabricated the tandem devices and performed the characterization and analysis. K.L.W. and J. Yin performed the DFT calculations. C.Y., S.Y., X.C. and J. Zhou fabricated the SHJ bottom cells. X.N. and R.S.B. performed the SCAPS-1D simulations. B.G., W.L., W.S., K.G., L.Y. and B.Y. contributed to characterizations and data interpretation. J. Yu, Y.Z., Y.W. and J. Zhu fabricated the tandem mini-module. W.A., S.D. and L.S. helped the characterization and thin films deposition. F.W. and H.H. performed the GIWAXS measurements. X.Z. and X.Y. supervised this project. All authors contributed to the discussion of the results and revision of the paper.
Correspondence to Jun Zhu, Lei Shi, Jun Yin, Xiaohong Zhang or Xinbo Yang.
J. Zhou, C.Y., S.Y. and X.C. are employees of Suzhou Maxwell Technologies Co. Ltd. J. Yu, Y.Z., Y.W. and J. Zhu are employees of Wuxi EliTe Solar Co. Ltd. W.A., S.D. and L.S. are employees of Hangzhou Zhongneng Photoelectricity Technology Co. Ltd. The other authors declare no competing interests.
Nature Energy thanks Christian Wolff, Renjun Guo 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.
Supplementary Tables 1–16, Figs. 1–44 and references.
Source data for Supplementary Figs. 4, 5, 6b, 7b, 8–10, 12,15c–e, 16, 18–23, 24b,c, 25, 26, 28–32, 34a, 35, 37–39, 42 and 44.
Source data for Fig. 1c–g.
Source data for Fig. 2a–e.
Source data for Fig. 3a–h.
Source data for Figs. 4b,d,g–l.
Source data for Figs. 5c,f–i.
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Cao, F., Li, Y., Wang, S. et al. High-performance perovskite/silicon tandem solar cells enabled by multifunctional titanium oxynitride recombination layers. Nat Energy (2026). https://doi.org/10.1038/s41560-026-02116-4
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