Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

Dual-side electrical refinement enables efficient industrial tunnel oxide passivating contact silicon solar cells

Nature Energy (2026)Cite this article

Subjects

Abstract

Crystalline silicon solar cells continue to dominate the photovoltaic industry, with tunnel oxide passivating contact (TOPCon) technology emerging as a prominent candidate. However, the efficiency of industrial-scale TOPCon solar cells remains limited by their suboptimal electrical performance, falling short of the Auger limit. Here we propose a dual-sided synergistic strategy that achieves a certified efficiency of 26.66% for industrial-scale TOPCon cells on M10-size wafers. The implementation of a front-side high-sheet-resistance boron emitter improves the passivation quality, and an optimized grid design reduces carrier transport losses. A rear-side double-layer tunnel oxide silicon/polysilicon structure suppresses silver-induced degradation by preventing silver diffusion from the electrodes into the silicon substrate, thereby maintaining excellent interfacial passivation. Moreover, the high crystallinity of the inner polysilicon layer, along with a lower concentration of inactive phosphorus dopants in the silicon substrate, leads to superior passivation performance. Rear-side localized thinning of the polysilicon layer also improves the bifaciality to 88.3%.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on SpringerLink
  • Instant access to the full article PDF.

USD 39.95

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Evolution and certification of TOPCon SCs.
Fig. 2: High-resistance boron emitter design and performance analysis.
Fig. 3: Microstructural characterization of the double poly-Si design.
Fig. 4: Double poly-Si design and performance analysis.

Data availability

The data that support the findings of this study are available within the article and its Supplementary Information. Source data are provided with this paper.

References

  1. Ballif, C., Haug, F.-J., Boccard, M., Verlinden, P. J. & Hahn, G. Status and perspectives of crystalline silicon photovoltaics in research and industry. Nat. Rev. Mater. 7, 597–616 (2022).

    Article  Google Scholar 

  2. Vicari Stefani, B. et al. Historical market projections and the future of silicon solar cells. Joule 7, 2684–2699 (2023).

    Article  Google Scholar 

  3. International Technology Roadmap for Photovoltaics (ITRPV) https://www.vdma.org/international-technology-roadmap-photovoltaic (VDMA, 2025).

  4. Feldmann, F., Bivour, M., Reichel, C., Hermle, M. & Glunz, S. W. Passivated rear contacts for high-efficiency n-type Si solar cells providing high interface passivation quality and excellent transport characteristics. Sol. Energy Mater. Sol. Cells 120, 270–274 (2014).

    Article  Google Scholar 

  5. Feldmann, F. et al. Tunnel oxide passivated contacts as an alternative to partial rear contacts. Sol. Energy Mater. Sol. Cells 131, 46–50 (2014).

    Article  Google Scholar 

  6. Tao, Y. et al. Large area tunnel oxide passivated rear contact n-type Si solar cells with 21.2% efficiency. Prog. Photovolt. 24, 830–835 (2016).

    Article  Google Scholar 

  7. Richter, A. et al. n-Type Si solar cells with passivating electron contact: identifying sources for efficiency limitations by wafer thickness and resistivity variation. Sol. Energy Mater. Sol. Cells 173, 96–105 (2017).

    Article  Google Scholar 

  8. Allen, T. G., Bullock, J., Yang, X., Javey, A. & De Wolf, S. Passivating contacts for crystalline silicon solar cells. Nat. Energy 4, 914–928 (2019).

    Article  Google Scholar 

  9. Köhler, M. et al. A silicon carbide-based highly transparent passivating contact for crystalline silicon solar cells approaching efficiencies of 24%. Nat. Energy 6, 529–537 (2021).

    Article  Google Scholar 

  10. Glunz, S. W. et al. Silicon-based passivating contacts: the TOPCon route. Prog. Photovolt. 31, 341–359 (2023).

    Article  Google Scholar 

  11. Li, W. et al. Passivating contacts for crystalline silicon solar cells: an overview of the current advances and future perspectives. Adv. Energy Mater. 14, 2304338 (2024).

    Article  Google Scholar 

  12. Darling, S. B., You, F., Veselka, T. & Velosa, A. Assumptions and the levelized cost of energy for photovoltaics. Energy Environ. Sci. 4, 3133–3139 (2011).

    Article  Google Scholar 

  13. Future belongs to TOPCon solar technology. Taiyang News https://taiyangnews.info/technology/exawatt-day-1-high-efficiency-solar-technologies-conference (2024).

  14. Kafle, B. et al. TOPCon – technology options for cost efficient industrial manufacturing. Sol. Energy Mater. Sol. Cells 227, 111100 (2021).

    Article  Google Scholar 

  15. Richter, A. et al. Design rules for high-efficiency both-sides-contacted silicon solar cells with balanced charge carrier transport and recombination losses. Nat. Energy 6, 429–438 (2021).

    Article  Google Scholar 

  16. Haase, F. et al. Laser contact openings for local poly-Si-metal contacts enabling 26.1%-efficient POLO-IBC solar cells. Sol. Energy Mater. Sol. Cells 186, 184–193 (2018).

    Article  Google Scholar 

  17. Green, M. A. et al. Solar cell efficiency tables (version 66). Prog. Photovolt. 33, 795–810 (2025).

    Article  Google Scholar 

  18. Wang, Q. et al. 26.35%-efficiency and high-bifaciality n-TOPCon solar cells enabled by UV-ps laser-induced selective modification of double-layered SiOx/n+-poly-Si passivating contacts. Energy Environ. Sci. 18, 9217–9229 (2025).

    Article  Google Scholar 

  19. Gao, K. et al. Bifacial tunnel oxide passivating contacts for silicon and perovskite/silicon tandem solar cells with improved efficiency. Nat. Energy https://doi.org/10.1038/s41560-026-02007-8 (2026).

  20. Polman, A., Knight, M., Garnett, E. C., Ehrler, B. & Sinke, W. C. Photovoltaic materials: present efficiencies and future challenges. Science 352, aad4424 (2016).

    Article  Google Scholar 

  21. Richter, A., Hermle, M. & Glunz, S. W. Reassessment of the limiting efficiency for crystalline silicon solar cells. IEEE J. Photovolt. 3, 1184–1191 (2013).

    Article  Google Scholar 

  22. Kirchartz, T. et al. The state of the art in photovoltaic materials and device research. Nat. Rev. Mater. 10, 335–354 (2025).

    Article  Google Scholar 

  23. Tepner, S. & Lorenz, A. Printing technologies for silicon solar cell metallization: a comprehensive review. Prog. Photovolt. 31, 557–590 (2023).

    Article  Google Scholar 

  24. Niewelt, T. et al. Reassessment of the intrinsic bulk recombination in crystalline silicon. Sol. Energy Mater. Sol. Cells 235, 111467 (2022).

    Article  Google Scholar 

  25. Schäfer, S. & Brendel, R. Accurate calculation of the absorptance enhances efficiency limit of crystalline silicon solar cells with Lambertian light trapping. IEEE J. Photovolt. 8, 1156–1158 (2018).

    Article  Google Scholar 

  26. Black, L. E. & Macdonald, D. H. On the quantification of Auger recombination in crystalline silicon. Sol. Energy Mater. Sol. Cells 234, 111428 (2022).

    Article  Google Scholar 

  27. Lin, H. et al. Silicon heterojunction solar cells with up to 26.81% efficiency achieved by electrically optimized nanocrystalline-silicon hole contact layers. Nat. Energy 8, 789–799 (2023).

    Article  Google Scholar 

  28. Wang, Q. et al. Boron tube diffusion process parameters for high-efficiency n-TOPCon solar cells with selective boron emitters. Sol. Energy Mater. Sol. Cells 253, 112231 (2023).

    Article  Google Scholar 

  29. Li, X. et al. Optimization of efficiency enhancement of TOPCon cells with boron selective emitter. Sol. Energy Mater. Sol. Cells 263, 112585 (2023).

    Article  Google Scholar 

  30. Krassowski, E. Laser Enhanced Contact Optimization – on the evolution and potentials of a disruptive technology for contact formation of industrial solar cells. In 2025 IEEE 53rd Photovoltaic Specialists Conference (PVSC) 0248–0250 (IEEE, 2025).

  31. Fellmeth, T. et al. Laser-enhanced contact optimization on iTOPCon solar cells. Prog. Photovolt. 30, 1393–1399 (2022).

    Article  Google Scholar 

  32. Chen, S. et al. Mechanisms and strategies for laser-enhanced contact optimization in tunnel oxide passivating contact solar cells with ultra-high sheet resistance emitters. Chem. Eng. J. 513, 162979 (2025).

    Article  Google Scholar 

  33. Fields, J. D. et al. The formation mechanism for printed silver-contacts for silicon solar cells. Nat. Commun. 7, 11143 (2016).

    Article  Google Scholar 

  34. Li, Y. et al. Design of advanced porous silver powder with high-sintering activity to improve silicon solar cells. Nano Res. 17, 3189–3197 (2024).

    Article  Google Scholar 

  35. Richter, A. et al. Both sides contacted silicon solar cells: options for approaching 26% efficiency. In 36th European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2019) (eds Lambert, F. et al.) 90–95 (Curran Associates, 2020).

  36. Schweigstill, T. et al. Advanced fine line printing with glass stencils: achieving metal contact fingers below 10 μm. Prog. Photovolt. 34, 29–38 (2026).

    Article  Google Scholar 

  37. Zhang, Y., Kim, M., Wang, L., Verlinden, P. & Hallam, B. Design considerations for multi-terawatt scale manufacturing of existing and future photovoltaic technologies: challenges and opportunities related to silver, indium and bismuth consumption. Energy Environ. Sci. 14, 5587–5610 (2021).

    Article  Google Scholar 

  38. Li, Y. et al. Insight into the contact mechanism of Ag/Al–Si interface for the front-side metallization of TOPCon silicon solar cells. Small Methods 9, 2400707 (2025).

    Article  Google Scholar 

  39. Hong, K.-K., Cho, S.-B., Huh, J.-Y., Park, H. J. & Jeong, J.-W. Role of PbO-based glass frit in Ag thick-film contact formation for crystalline Si solar cells. Met. Mater. Int. 15, 307–312 (2009).

    Article  Google Scholar 

  40. Hong, K.-K. et al. Mechanism for the formation of Ag crystallites in the Ag thick-film contacts of crystalline Si solar cells. Sol. Energy Mater. Sol. Cells 93, 898–904 (2009).

    Article  Google Scholar 

  41. Zhou, R. et al. Nano-size Joule-heating to achieve low-Ohmic Ag–Si contact on boron emitters of n-TOPCon solar cells. Small 21, 2409628 (2025).

    Article  Google Scholar 

  42. Kim, H.-S. et al. Electrochemical nature of contact firing reactions for screen-printed silicon solar cells: origin of “gray finger” phenomenon. Prog. Photovolt. 24, 1237–1250 (2016).

    Article  Google Scholar 

  43. Feldmann, F., Reichel, C., Müller, R. & Hermle, M. The application of poly-Si/SiOx contacts as passivated top/rear contacts in Si solar cells. Sol. Energy Mater. Sol. Cells 159, 265–271 (2017).

    Article  Google Scholar 

  44. Wang, Q. et al. High-efficiency n-TOPCon bifacial solar cells with selective poly-Si based passivating contacts. Sol. Energy Mater. Sol. Cells 259, 112458 (2023).

    Article  Google Scholar 

  45. Cao, K. et al. Physical mechanisms and design strategies for high-efficiency back contact tunnel oxide passivating contact solar cells. Sol. Energy Mater. Sol. Cells 289, 113656 (2025).

    Article  Google Scholar 

  46. Du, H. et al. High-performance boron emitters for tunnel oxide passivating contact solar cells enabled by multi-layer PECVD-deposited boron source structures. Chem. Eng. J. 515, 163487 (2025).

    Article  Google Scholar 

  47. Peibst, R. et al. Towards 28 %-efficient Si single-junction solar cells with better passivating POLO junctions and photonic crystals. Sol. Energy Mater. Sol. Cells 238, 111560 (2022).

    Article  Google Scholar 

  48. Rienäcker, M. et al. Junction resistivity of carrier-selective polysilicon on oxide junctions and its impact on solar cell performance. IEEE J. Photovolt. 7, 11–18 (2017).

    Article  Google Scholar 

  49. Green, M. A. et al. Solar cell efficiency tables (version 65). Prog. Photovolt. 33, 3–15 (2025).

    Article  Google Scholar 

  50. Glunz, S. W. et al. The irresistible charm of a simple current flow pattern – 25% with a solar cell featuring a full-area back contact. In 31st European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2015) (eds Rinck, S. et al.) 259–263 (Curran Associates, 2016).

  51. Hermle, M. et al. Approaching efficiencies above 25% with both sides-contacted silicon solar cells. In 2015 IEEE 42nd Photovoltaic Specialist Conference (PVSC) 1–3 (IEEE, 2015).

  52. Trina Solar’s N-type i-TOPCon solar cell achieves a breakthrough efficiency of 24.58%. https://www.trinasolar.com/cn/20190528-1206/ (2019).

  53. Trina Solar breaks world record yet again by setting i-TOPCon cell efficiency at 25.5%. Trina Solar News Center https://www.trinasolar.com/en-apac/resources/newsroom/aptrina-solar-breaks-world-record-yet-again-setting-i-topcon-cell-efficiency-255/ (2022).

  54. Jinko Solar sets world record with 24.2% efficiency for large-area N-type TOPCon solar cells. Jinko Solar https://www.jinkosolar.com/site/newsdetail/261 (2019).

  55. 24.8% efficiency! The time is now for Jinko Solar’s third-generation TOPCon Tiger Neo. Jinko Solar https://www.jinkosolar.com/site/newsdetail/2122 (2020).

  56. Jinko Solar achieves 24.90% conversion efficiency for large-area n-type monocrystalline silicon single-junction solar cell, setting new world record. Jinko Solar https://www.jinkosolar.com/site/newsdetail/860 (2021).

  57. Jinko Solar: ‘Record’ 25.25% efficiency for TOPCon cell. Taiyang News https://taiyangnews.info/technology/jinkosolar-record-25-25-efficiency-for-n-type-mono-cell (2021).

  58. Jinko Solar achieves 25.4% efficiency for high-efficiency N-type monocrystalline silicon single-junction solar cell, setting new world record. Jinko Solar https://www.jinkosolar.com/site/newsdetail/934 (2021).

  59. Jinko Solar achieves 25.7% efficiency for high-performance N-type monocrystalline silicon single-junction solar cell, setting new world record. Jinko Solar https://www.jinkosolar.com/site/newsdetail/1165 (2022).

  60. 26.1%! Jinko Solar breaks conversion efficiency record again for high-efficiency N-type TOPCon solar cell. Jinko Solar https://www.jinkosolar.com/site/newsdetail/1320 (2022).

  61. 26.4%! Jinko Solar sets new record for 182 TOPCon cell conversion efficiency. Jinko Solar https://www.jinkosolar.com/site/newsdetail/1387 (2022).

  62. Green, M. A. et al. Solar cell efficiency tables (version 64). Prog. Photovolt. 32, 425–441 (2024).

    Article  Google Scholar 

  63. Xie, Z. et al. 27%-efficiency silicon heterojunction cell with 98.6% cell-to-module ratio driving new momentum towards the 29.4% limit. Nat. Commun. 16, 9421 (2025).

    Article  Google Scholar 

  64. LONGi once again sets new world record for HJT solar cell efficiency. LONGi News https://www.longi.com/en/news/new-hjt-world-record/ (2022).

  65. LONGi sets new world record of 25.82% for HJT solar cell efficiency. LONGi News https://www.longi.com/en/news/6751/ (2021).

Download references

Acknowledgements

J. Ye acknowledges financial support from the Key Research and Development Program of Zhejiang Province (2021C01006), the Key Research and Development Program of Anhui Province (202423h08050004) and the Ningbo International Science and Technology Cooperation Program (2024H028). Y. Zeng acknowledges financial support from the Key Research and Development Program of Zhejiang Province (2024C01055), the Ningbo “Innovation 2025” Major Project (2022Z114), the Ningbo “Innovation 2035” Major Project (2024Z243), the National Natural Science Foundation of China (62474178) and the Science and Technology Projects in Liaoning Province 2021 (2021JHI/10400104).

Author information

Author notes

  1. These authors contributed equally: Zhenhai Yang, Sheshicheng Chen, Jie Mao, Kun Cao, Zunke Liu, Haojiang Du, Zhao Wang.

Authors and Affiliations

  1. Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences (CAS), Ningbo, China

    Zhenhai Yang, Sheshicheng Chen, Zunke Liu, Haojiang Du, Yuheng Zeng & Jichun Ye

  2. School of Optoelectronic Science and Engineering & Collaborative Innovation Center of Suzhou Nano Science and Technology; Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province & Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou, China

    Zhenhai Yang & Kun Cao

  3. Zhejiang Jinko Solar Co., Ltd, Haining, China

    Jie Mao, Zhao Wang, Yuanfang Zhang, Jinjin Chen, Jiajia Zhu, Menglei Xu, Wenqi Li, Hao Jin, Xinyu Zhang, Jie Yang & Peiting Zheng

  4. College of Materials and Chemistry, China Jiliang University, Hangzhou, China

    Huiwei Du

Authors
  1. Zhenhai Yang
    View author publications

    Search author on:PubMed Google Scholar

  2. Sheshicheng Chen
    View author publications

    Search author on:PubMed Google Scholar

  3. Jie Mao
    View author publications

    Search author on:PubMed Google Scholar

  4. Kun Cao
    View author publications

    Search author on:PubMed Google Scholar

  5. Zunke Liu
    View author publications

    Search author on:PubMed Google Scholar

  6. Haojiang Du
    View author publications

    Search author on:PubMed Google Scholar

  7. Zhao Wang
    View author publications

    Search author on:PubMed Google Scholar

  8. Yuanfang Zhang
    View author publications

    Search author on:PubMed Google Scholar

  9. Jinjin Chen
    View author publications

    Search author on:PubMed Google Scholar

  10. Jiajia Zhu
    View author publications

    Search author on:PubMed Google Scholar

  11. Menglei Xu
    View author publications

    Search author on:PubMed Google Scholar

  12. Wenqi Li
    View author publications

    Search author on:PubMed Google Scholar

  13. Hao Jin
    View author publications

    Search author on:PubMed Google Scholar

  14. Xinyu Zhang
    View author publications

    Search author on:PubMed Google Scholar

  15. Huiwei Du
    View author publications

    Search author on:PubMed Google Scholar

  16. Jie Yang
    View author publications

    Search author on:PubMed Google Scholar

  17. Peiting Zheng
    View author publications

    Search author on:PubMed Google Scholar

  18. Yuheng Zeng
    View author publications

    Search author on:PubMed Google Scholar

  19. Jichun Ye
    View author publications

    Search author on:PubMed Google Scholar

Contributions

Z.Y. conceived of the idea, designed the overall experiments, led the project and wrote and revised the paper. J.M. produced and provided the cell samples. S.C., Z.L., Haojiang Du and Z.W. contributed to the materials characterization and participated in data interpretation (S.C. performed the characterization and analysis, including PL, EL, TEM and SEM experiments; Z.L. carried out the ECV, Raman and related characterization and analysis; Haojiang Du was responsible for the EQE, SIMS and related characterization and analysis; and Z.W. performed the passivation measurements). K.C. carried out the cell simulation and data analysis. Huiwei Du, J. Yang, P.Z., Y. Zeng and J. Ye managed the project and participated in the experimental design. Y. Zhang, J.C., J.Z., M.X., W.L., H.J. and X.Z. discussed the results. Z.Y. and K.C. were responsible for the figures, tables and preparation for publication. Y. Zeng and J. Ye provided resources and funding support. J. Yang and P.Z. established the research and development plan and led the team in achieving the certified efficiency. All authors commented on the paper.

Corresponding authors

Correspondence to Huiwei Du, Jie Yang, Peiting Zheng, Yuheng Zeng or Jichun Ye.

Ethics declarations

Competing interests

J.M., Z.W., Y. Zhang, J.C., J.Z., M.X., W.L., H.J., X.Z., J. Yang and P.Z. are employed by Zhejiang Jinko Solar Co., Ltd. The other authors declare no competing interests.

Peer review

Peer review information

Nature Energy thanks Franz-Josef Haug and Byungsul Min and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Note 1, Figs. 1–15 and Tables 1 and 2.

Reporting Summary

Supplementary Data 1

Source data for Supplementary Figs. 1, 10, 11 and 12.

Source data

Source Data Fig. 2

Statistical source data.

Source Data Fig. 4

Statistical source data.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Yang, Z., Chen, S., Mao, J. et al. Dual-side electrical refinement enables efficient industrial tunnel oxide passivating contact silicon solar cells. Nat Energy (2026). https://doi.org/10.1038/s41560-026-01982-2

Download citation

  • Received:

  • Accepted:

  • Published:

  • Version of record:

  • DOI: https://doi.org/10.1038/s41560-026-01982-2

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing