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Elemental de-mixing-induced epitaxial kesterite/CdS interface enabling 13%-efficiency kesterite solar cells

Nature Energy volume 7, pages 966–977 (2022)Cite this article

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Abstract

The conversion efficiency of kesterite solar cells has been stagnated at 12.6% since 2013. In contrast to chalcopyrite solar cells, the performance of kesterite solar cells is seriously limited by heterojunction interface recombination. Here we demonstrate kesterite/CdS heterojunction is constructed on a Zn-poor surface due to the dissolution of Zn2+ during chemical bath deposition. The occupation of Cd2+ on the Zn site and re-deposition of Zn2+ into CdS creates a defective and lattice-mismatched interface. Low-temperature annealing of the kesterite/CdS junction drives migration of Cd2+ from absorber back to CdS and Zn2+ from absorber bulk to surface, achieving a gradient composition and reconstructing an epitaxial interface. This greatly reduces interface recombination and improves device open-circuit voltage and fill factor. We achieve certified 12.96% efficiency small-area (0.11 cm2) and certified 11.7% efficiency large-area (1.1 cm2) kesterite devices. The findings are expected to advance the development of kesterite solar cells.

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Fig. 1: Fabrication procedure and photovoltaic performance.
Fig. 2: The characteristics of ACZTSSe and CISSe solar cells.
Fig. 3: The heterojunction interfaces.
Fig. 4: Surface and interface elements migration.
Fig. 5: Large-area device and stability.

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All data supporting the findings of this study are available within the paper and Supplementary Information files. Source data are provided with this paper.

References

  1. Todorov, T. K. et al. Beyond 11% efficiency: characteristics of state-of-the-art Cu2ZnSn(S,Se)4 solar cells. Adv. Energy Mater. 3, 34–38 (2013).

    Article  Google Scholar 

  2. Yan, C. et al. Cu2ZnSnS4 solar cells with over 10% power conversion efficiency enabled by heterojunction heat treatment. Nat. Energy 3, 764–772 (2018).

    Article  Google Scholar 

  3. Giraldo, S. et al. Progress and perspectives of thin film kesterite photovoltaic technology: a critical review. Adv. Mater. 31, 1806692 (2019).

    Article  Google Scholar 

  4. Xu, X. et al. Efficient and composition-tolerant kesterite Cu2ZnSn(S, Se)4 solar cells derived from an in situ formed multifunctional carbon framework. Adv. Energy Mater. 11, 2102298 (2021).

    Article  Google Scholar 

  5. Fonoll-Rubio, R. et al. Insights into interface and bulk defects in a high efficiency kesterite-based device. Energy Environ. Sci. 14, 507–523 (2021).

    Article  Google Scholar 

  6. Wang, W. et al. Device characteristics of CZTSSe thin-film solar cells with 12.6% efficiency. Adv. Energy Mater. 4, 1301465 (2014).

    Article  Google Scholar 

  7. Son, D.-H. et al. Effect of solid-H2S gas reactions on CZTSSe thin film growth and photovoltaic properties of a 12.62% efficiency device. J. Mater. Chem. A 7, 25279–25289 (2019).

    Article  Google Scholar 

  8. Nakamura, M. et al. Cd-free Cu(In,Ga)(Se,S)2 thin-film solar cell with record efficiency of 23.35%. IEEE J. Photovolt. 9, 1863–1867 (2019).

    Article  Google Scholar 

  9. Shin, D. et al. Defect engineering in multinary Earth-abundant chalcogenide photovoltaic materials. Adv. Energy Mater. 7, 1602366 (2017).

    Article  Google Scholar 

  10. Romanyuk, Y. E. et al. Doping and alloying of kesterites. J. Phys.: Energy 1, 044004 (2019).

    Google Scholar 

  11. Fu, J. et al. Ag, Ge dual-gradient substitution for low-energy loss and high-efficiency kesterite solar cells. J. Mater. Chem. A 8, 22292–22301 (2020).

    Article  Google Scholar 

  12. Gong, Y. et al. Sn4+ precursor enables 12.4% efficient kesterite solar cell from DMSO solution with open circuit voltage deficit below 0.30 V. Sci. China Mater. 64, 52–60 (2021).

    Article  Google Scholar 

  13. Gong, Y. et al. Identifying the origin of the Voc deficit of kesterite solar cells from the two grain growth mechanisms induced by Sn2+ and Sn4+ precursors in DMSO solution. Energy Environ. Sci. 14, 2369–2380 (2021).

    Article  Google Scholar 

  14. Scragg, J. J. S. et al. A low-temperature order–disorder transition in Cu2ZnSnS4 thin films. Appl. Phys. Lett. 104, 041911 (2014).

    Article  Google Scholar 

  15. Rey, G. et al. Ordering kesterite improves solar cells: a low temperature post-deposition annealing study. Sol. Energy Mater. Sol. Cells 151, 131–138 (2016).

    Article  Google Scholar 

  16. Sardashti, K. et al. Impact of nanoscale elemental distribution in high-performance kesterite solar cells. Adv. Energy Mater. 5, 1402180 (2015).

    Article  Google Scholar 

  17. Sardashti, K. et al. Nano-scale compositional analysis of surfaces and interfaces in Earth-abundant kesterite solar cells. J. Mater. Res. 31, 3473–3481 (2016).

    Article  Google Scholar 

  18. Kim, S.-Y. et al. Effect of Cu–Sn–Se liquid phase on grain growth and efficiency of CZTSSe solar cells. Adv. Energy Mater. 10, 1903173 (2020).

    Article  Google Scholar 

  19. Haight, R. et al. Electronic and elemental properties of the Cu2ZnSn(S,Se)4 surface and grain boundaries. Appl. Phys. Lett. 104, 033902 (2014).

    Article  Google Scholar 

  20. Kim, J. et al. High efficiency Cu2ZnSn(S,Se)4 solar cells by applying a double In2S3/CdS emitter. Adv. Mater. 26, 7427–7431 (2014).

    Article  Google Scholar 

  21. Su, Z. et al. Device postannealing enabling over 12% efficient solution-processed Cu2ZnSnS4 solar cells with Cd2+ substitution. Adv. Mater. 32, 2000121 (2020).

    Article  Google Scholar 

  22. Nisika et al. Progress and prospects of CZTSSe/CdS interface engineering to combat high open-circuit voltage deficit of kesterite photovoltaics: a critical review. J. Mater. Chem. A 8, 21547–21584 (2020).

    Article  Google Scholar 

  23. Lu, X. et al. Heterojunction post-heat treatment process driving high efficiency for Cu2ZnSnS4 solar cell. Sol. Energy Mater. Sol. Cells 230, 111204 (2021).

    Article  Google Scholar 

  24. Koprek, A. et al. Cd and impurity redistribution at the CdS/CIGS interface after annealing of CIGS-based solar cells resolved by atom probe tomography. IEEE J. Photovolt. 7, 313–321 (2017).

    Article  Google Scholar 

  25. Gong, Y. et al. Ag incorporation with controlled grain growth enables 12.5% efficient kesterite solar cell with open circuit voltage reached 64.2% Shockley–Queisser limit. Adv. Funct. Mater. 31, 2101927 (2021).

    Article  Google Scholar 

  26. Wang, S. et al. Defects and surface electrical property transformation induced by elemental interdiffusion at the p–n heterojunction via high-temperature annealing. ACS Appl. Mater. Interfaces 13, 12211–12220 (2021).

    Article  Google Scholar 

  27. Green, M. A. et al. Solar cell efficiency tables (version 59). Prog. Photovoltaics Res. Appl. 30, 3–12 (2022).

    Article  Google Scholar 

  28. Li, Y. et al. Exploiting electrical transients to quantify charge loss in solar cells. Joule 4, 472–489 (2020).

    Article  Google Scholar 

  29. Yu, S. et al. Solution-processed chalcopyrite solar cells: the grain growth mechanism and the effects of Cu/In mole ratio. Adv. Energy Mater. 12, 2103644 (2022).

    Article  Google Scholar 

  30. Nakada, T. & Kunioka, A. Direct evidence of Cd diffusion into Cu(In, Ga)Se2 thin films during chemical-bath deposition process of CdS films. Appl. Phys. Lett. 74, 2444–2446 (1999).

    Article  Google Scholar 

  31. El Hajraoui, K. et al. Atomic-scale interface modification improves the performance of Cu(In1–xGax)Se2/Zn(O,S) heterojunction solar cells. ACS Appl. Mater. Interfaces 13, 44207–44213 (2021).

    Article  Google Scholar 

  32. Bar, M. et al. Zn–Se–Cd–S interlayer formation at the CdS/Cu2ZnSnSe4 thin-film solar cell interface. ACS Energy Lett. 2, 1632–1640 (2017).

    Article  Google Scholar 

  33. Ennaoui, A. et al. Chemical-bath ZnO buffer layer for CuInS2 thin-film solar cells. Sol. Energy Mater. Sol. Cells 54, 277–286 (1998).

    Article  Google Scholar 

  34. Lee, Y. S. et al. Cu2ZnSnSe4 thin-film solar cells by thermal co-evaporation with 11.6% efficiency and improved minority carrier diffusion length. Adv. Energy Mater. 5, 1401372 (2015).

    Article  Google Scholar 

  35. Zhang, C. et al. A simple and efficient solar cell parameter extraction method from a single current-voltage curve. J. Appl. Phys. 110, 064504 (2011).

    Article  Google Scholar 

  36. Shi, J. et al. Opto-electro-modulated transient photovoltage and photocurrent system for investigation of charge transport and recombination in solar cells. Rev. Sci. Instrum. 87, 123107 (2016).

    Article  Google Scholar 

Download references

Acknowledgements

H.X. and W.Y. acknowledge the funding from the National Key Research and Development Program of China (grant number 2019YFE0118100) and the National Natural Science Foundation of China (grant number 22075150). Q.M. acknowledges funding from the National Natural Science Foundation of China (number U2002216 and number 51972332). S.C. acknowledges funding from the National Natural Science Foundation of China (grant number 12174060) and the Shanghai Academic/Technology Research Leader (grant number 19XD1421300). R.G. acknowledges the support from the Molecular Analysis Facility, a National Nanotechnology Coordinated Infrastructure site at the University of Washington, which is supported, in part, by the National Science Foundation (NNCI-1542101), the University of Washington, the Molecular Engineering & Sciences Institute, the Clean Energy Institute and the National Institutes of Health. We thank X. Sha and T. Qiu of Zeiss for preparing TEM lamellae by cryo-FIB and TEM characterization. We acknowledge D.S. Ginger for useful discussion and comments.

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Author notes

  1. These authors contributed equally: Yuancai Gong, Qiang Zhu.

Authors and Affiliations

  1. State Key Laboratory of Organic Electronics and Information Displays & Institute of Advanced Materials, Nanjing University of Posts & Telecommunications, Nanjing, P. R. China

    Yuancai Gong, Qiang Zhu, Bingyan Li, Chunxu Xiang, Yage Zhou, Qi Dai, Weibo Yan & Hao Xin

  2. Key Laboratory for Computational Physical Sciences (MOE), State Key Laboratory of ASIC and System and School of Microelectronics, Fudan University, Shanghai, P. R. China

    Shanshan Wang & Shiyou Chen

  3. Beijing Key Laboratory for New Energy Materials and Devices, Beijing National Laboratory for Condensed Matter Physics, Key Laboratory for Renewable Energy (CAS), Institute of Physics, Chinese Academy of Sciences (CAS), Beijing, P. R. China

    Biwen Duan, Licheng Lou & Qingbo Meng

  4. Department of Chemistry, University of Washington, Seattle, WA, USA

    Erin Jedlicka & Rajiv Giridharagopal

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  1. Yuancai Gong
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Contributions

H.X. conceived the idea. H.X. and Y.G. designed the project and co-wrote the manuscript. Y.G. and Q.Z. fabricated and characterized the devices; B.L. fabricated and characterized the CISSe solar cells; S.W. and S.C. performed first-principles calculations and analysis of interface structure and electronic structure. B.D. and L.L performed M-TPV, M-TPC and C–V-DLCP analysis; C.X. and Q.D. performed SEM measurement and discussed the TEM data; E.J. and R.G. performed GDOES measurements and analysed the data; Y.Z. provided important assistance in device fabrication. H.X. and W.Y. supervised the research at NJUPT; Q.M. supervised the research at CAS; S.C. supervised the research at Fudan University. All authors discussed and analysed the results.

Corresponding authors

Correspondence to Shiyou Chen, Qingbo Meng or Hao Xin.

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Nature Energy thanks Edgardo Saucedo and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–21, Notes 1–8 and Tables 1–7.

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Source data

Source Data Fig. 1

Unprocessed J–V and EQE data, statistical device data, integrated JSC from EQE, derivative of EQE versus wavelength.

Source Data Fig. 2

Unprocessed TPV, TPC, Raman, C–V and DLCP data and temperature-dependent VOC data.

Source Data Fig. 3

Unprocessed EDX line scan profile data.

Source Data Fig. 4

Unprocessed XPS and J–V data, element content change with CBD time.

Source Data Fig. 5

Unprocessed J–V, EQE data and device stability data.

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Gong, Y., Zhu, Q., Li, B. et al. Elemental de-mixing-induced epitaxial kesterite/CdS interface enabling 13%-efficiency kesterite solar cells. Nat Energy 7, 966–977 (2022). https://doi.org/10.1038/s41560-022-01132-4

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