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Monolithic all-perovskite tandem solar cells with 24.8% efficiency exploiting comproportionation to suppress Sn(ii) oxidation in precursor ink


Combining wide-bandgap and narrow-bandgap perovskites to construct monolithic all-perovskite tandem solar cells offers avenues for continued increases in photovoltaic (PV) power conversion efficiencies (PCEs). However, actual efficiencies today are diminished by the subpar performance of narrow-bandgap subcells. Here we report a strategy to reduce Sn vacancies in mixed Pb–Sn narrow-bandgap perovskites that use metallic tin to reduce the Sn4+ (an oxidation product of Sn2+) to Sn2+ via a comproportionation reaction. We increase, thereby, the charge-carrier diffusion length in narrow-bandgap perovskites to 3 μm for the best materials. We obtain a PCE of 21.1% for 1.22-eV narrow-bandgap solar cells. We fabricate monolithic all-perovskite tandem cells with certified PCEs of 24.8% for small-area devices (0.049 cm2) and of 22.1% for large-area devices (1.05 cm2). The tandem cells retain 90% of their performance following 463 h of operation at the maximum power point under full 1-sun illumination.

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Fig. 1: Mixed Pb–Sn narrow-bandgap perovskite films fabricated from Sn4+-containing and Sn-reduced (Sn4+-free) precursor solutions.
Fig. 2: Charge dynamics of mixed Pb–Sn narrow-bandgap perovskites.
Fig. 3: PV performance of mixed Pb–Sn narrow-bandgap PSCs.
Fig. 4: Performance and stability of monolithic all-perovskite tandem solar cells.

Data availability

All data that support the findings in this study are present in the paper and the Supplementary Information. Additional data related to this study are available from the corresponding authors upon reasonable request.


  1. 1.

    Rong, Y. et al. Challenges for commercializing perovskite solar cells. Science 361, eaat8235 (2018).

    Article  Google Scholar 

  2. 2.

    Jiang, Q. et al. Surface passivation of perovskite film for efficient solar cells. Nat. Photonics 13, 460–466 (2019).

    Article  Google Scholar 

  3. 3.

    Green, M. A. et al. Solar cell efficiency tables (version 54). Prog. Photovolt. Res. Appl. 27, 565–575 (2019).

    Article  Google Scholar 

  4. 4.

    Eperon, G. E., Hörantner, M. T. & Snaith, H. J. Metal halide perovskite tandem and multiple-junction photovoltaics. Nat. Rev. Chem. 1, 0095 (2017).

    Article  Google Scholar 

  5. 5.

    Leijtens, T., Bush, K. A., Prasanna, R. & McGehee, M. D. Opportunities and challenges for tandem solar cells using metal halide perovskite semiconductors. Nat. Energy 3, 828–838 (2018).

    Article  Google Scholar 

  6. 6.

    Wang, C., Song, Z., Li, C., Zhao, D. & Yan, Y. Low-bandgap mixed tin-lead perovskites and their applications in all-perovskite tandem solar cells. Adv. Funct. Mater. 1808801 (2019).

  7. 7.

    Hao, F., Stoumpos, C. C., Chang, R. P. H. & Kanatzidis, M. G. Anomalous band gap behavior in mixed Sn and Pb perovskites enables broadening of absorption spectrum in solar cells. J. Am. Chem. Soc. 136, 8094–8099 (2014).

    Article  Google Scholar 

  8. 8.

    Ogomi, Y. et al. CH3NH3SnxPb(1–x)I3 perovskite solar cells covering up to 1060 nm. J. Phys. Chem. Lett. 5, 1004–1011 (2014).

    Article  Google Scholar 

  9. 9.

    Liao, W. et al. Fabrication of efficient low-bandgap perovskite solar cells by combining formamidinium tin iodide with methylammonium lead iodide. J. Am. Chem. Soc. 138, 12360–12363 (2016).

    Article  Google Scholar 

  10. 10.

    Konstantakou, M. & Stergiopoulos, T. A critical review on tin halide perovskite solar cells. J. Mater. Chem. A 5, 11518–11549 (2017).

    Article  Google Scholar 

  11. 11.

    Ke, W. & Kanatzidis, M. G. Prospects for low-toxicity lead-free perovskite solar cells. Nat. Commun. 10, 965 (2019).

    Article  Google Scholar 

  12. 12.

    Chung, I. et al. CsSnI3: semiconductor or metal? High electrical conductivity and strong near-infrared photoluminescence from a single material. High hole mobility and phase-transitions. J. Am. Chem. Soc. 134, 8579–8587 (2012).

    Article  Google Scholar 

  13. 13.

    Ma, L. et al. Carrier diffusion lengths of over 500 nm in lead-free perovskite CH3NH3SnI3 films. J. Am. Chem. Soc. 138, 14750–14755 (2016).

    Article  Google Scholar 

  14. 14.

    Liao, W. et al. Lead-free inverted planar formamidinium tin triiodide perovskite solar cells achieving power conversion efficiencies up to 6.22%. Adv. Mater. 28, 9333–9340 (2016).

    Article  Google Scholar 

  15. 15.

    Lee, S. J. et al. Fabrication of efficient formamidinium tin iodide perovskite solar cells through SnF2–pyrazine complex. J. Am. Chem. Soc. 138, 3974–3977 (2016).

    Article  Google Scholar 

  16. 16.

    Tai, Q. et al. Antioxidant grain passivation for air-stable tin-based perovskite solar cells. Angew. Chem. Int. Ed. 58, 806–810 (2019).

    Article  Google Scholar 

  17. 17.

    Gu, F. et al. Improving performance of lead-free formamidinium tin triiodide perovskite solar cells by tin source purification. Sol. RRL 2, 1800136 (2018).

    Article  Google Scholar 

  18. 18.

    Rajagopal, A., Liang, P.-W., Chueh, C.-C., Yang, Z. & Jen, A. K. Y. Defect passivation via a graded fullerene heterojunction in low-bandgap Pb–Sn binary perovskite photovoltaics. ACS Energy Lett. 2, 2531–2539 (2017).

    Article  Google Scholar 

  19. 19.

    Xu, G. et al. Integrating ultrathin bulk-heterojunction organic semiconductor intermediary for high-performance low-bandgap perovskite solar cells with low energy loss. Adv. Funct. Mater. 28, 1804427 (2018).

    Article  Google Scholar 

  20. 20.

    Tang, H., Shang, Y., Zhou, W., Peng, Z. & Ning, Z. Energy level tuning of PEDOT:PSS for high performance tin-lead mixed perovskite solar cells. Sol. RRL 3, 1800256 (2019).

    Article  Google Scholar 

  21. 21.

    Zhao, D. et al. Low-bandgap mixed tin–lead iodide perovskite absorbers with long carrier lifetimes for all-perovskite tandem solar cells. Nat. Energy 2, 17018 (2017).

    Article  Google Scholar 

  22. 22.

    Zhao, D. et al. Efficient two-terminal all-perovskite tandem solar cells enabled by high-quality low-bandgap absorber layers. Nat. Energy 3, 1093–1100 (2018).

    Article  Google Scholar 

  23. 23.

    Prasanna, R. et al. Band gap tuning via lattice contraction and octahedral tilting in perovskite materials for photovoltaics. J. Am. Chem. Soc. 139, 11117–11124 (2017).

    Article  Google Scholar 

  24. 24.

    Li, C. et al. Reducing saturation-current density to realize high-efficiency low-bandgap mixed tin-lead halide perovskite solar cells. Adv. Energy Mater. 9, 1803135 (2019).

    Article  Google Scholar 

  25. 25.

    Tong, J. et al. Carrier lifetimes of >1 μs in Sn-Pb perovskites enable efficient all-perovskite tandem solar cells. Science 364, 475–479 (2019).

    Article  Google Scholar 

  26. 26.

    Leijtens, T. et al. Tin–lead halide perovskites with improved thermal and air stability for efficient all-perovskite tandem solar cells. Sustain. Energy Fuels 2, 2450–2459 (2018).

    Article  Google Scholar 

  27. 27.

    Eperon, G. E. et al. Perovskite-perovskite tandem photovoltaics with optimized band gaps. Science 354, 861–865 (2016).

    Article  Google Scholar 

  28. 28.

    Rajagopal, A. et al. Highly efficient perovskite-perovskite tandem solar cells reaching 80% of the theoretical limit in photovoltage. Adv. Mater. 29, 1702140 (2017).

    Article  Google Scholar 

  29. 29.

    Jung, E. H. et al. Efficient, stable and scalable perovskite solar cells using poly(3-hexylthiophene). Nature 567, 511–515 (2019).

    Article  Google Scholar 

  30. 30.

    Rajagopal, A., Stoddard, R. J., Jo, S. B., Hillhouse, H. W. & Jen, A. K. Overcoming the photovoltage plateau in large bandgap perovskite photovoltaics. Nano Lett. 18, 3985–3993 (2018).

    Article  Google Scholar 

  31. 31.

    Sahli, F. et al. Improved optics in monolithic perovskite/silicon tandem solar cells with a nanocrystalline silicon recombination junction. Adv. Energy Mater. 8, 1701609 (2018).

    Article  Google Scholar 

  32. 32.

    Palmstrom, A. F. et al. Enabling flexible all-perovskite tandem solar cells. Joule 1–12 (2019).

    Article  Google Scholar 

  33. 33.

    Lee, S. J. et al. Reducing carrier density in formamidinium tin perovskites and its beneficial effects on stability and efficiency of perovskite solar cells. ACS Energy Lett. 3, 46–53 (2018).

    Article  Google Scholar 

  34. 34.

    Stoumpos, C. C., Malliakas, C. D. & Kanatzidis, M. G. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties. Inorg. Chem. 52, 9019–9038 (2013).

    Article  Google Scholar 

  35. 35.

    Leijtens, T., Prasanna, R., Gold-Parker, A., Toney, M. F. & McGehee, M. D. Mechanism of tin oxidation and stabilization by lead substitution in tin halide perovskites. ACS Energy Lett. 2, 2159–2165 (2017).

    Article  Google Scholar 

  36. 36.

    Vanýsek, P. Handbook of Chemistry and Physics 93rd edn (Ed. Haynes, W. M.) 5–80 (Chemical Rubber Company, 2012).

  37. 37.

    Wehrenfennig, C., Eperon, G. E., Johnston, M. B., Snaith, H. J. & Herz, L. M. High charge carrier mobilities and lifetimes in organolead trihalide perovskites. Adv. Mater. 26, 1584–1589 (2014).

    Article  Google Scholar 

  38. 38.

    McMeekin, D. P. et al. A mixed-cation lead mixed-halide perovskite absorber for tandem solar cells. Science 351, 151–155 (2016).

    Article  Google Scholar 

  39. 39.

    Saidaminov, M. I. et al. Suppression of atomic vacancies via incorporation of isovalent small ions to increase the stability of halide perovskite solar cells in ambient air. Nat. Energy 3, 648–654 (2018).

    Article  Google Scholar 

  40. 40.

    Aristidou, N. et al. Fast oxygen diffusion and iodide defects mediate oxygen-induced degradation of perovskite solar cells. Nat. Commun. 8, 15218 (2017).

    Article  Google Scholar 

  41. 41.

    Saliba, M. et al. Incorporation of rubidium cations into perovskite solar cells improves photovoltaic performance. Science 354, 206–209 (2016).

    Article  Google Scholar 

  42. 42.

    Tan, H. et al. Efficient and stable solution-processed planar perovskite solar cells via contact passivation. Science 355, 722–726 (2017).

    Article  Google Scholar 

  43. 43.

    Han, Q. et al. High-performance perovskite/Cu(In,Ga)Se2 monolithic tandem solar cells. Science 361, 904–908 (2018).

    Article  Google Scholar 

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This work is supported by the National Key R&D Programme of China (grant no. 2018YFB1500102), the Thousand Talent Programme for Young Outstanding Scientists in China and the Fundamental Research Funds for the Central Universities (grant no. 0213/14380122). The work of C.Z. is supported by the National Key R&D Programme of China (grant no. 2017YFA0303703) and the National Natural Science Foundation of China (grant no. 91833305). The work of J.Z. is supported by the National Natural Science Foundation of China (grant no. 11574143). The authors thank Q. Shi at SIMIT (Shanghai) for his guidance on the JV measurements of tandem solar cells.

Author information




H.T. conceived the idea and directed the overall project. R.L., K.X., C.Z., J.Z., E.H.S. and H.T. designed the experiments. R.L. and K.X. fabricated all the devices and conducted the characterization. Z.Q., C.Z. and M.X. carried out the THz measurements and corresponding data analysis. Q.H., M.W., M.I.S. and Y.G. helped on the device fabrication and characterization. A.L. helped on ALD processing. J.X. helped on ultraviolet–visible–near-infrared spectroscopy measurements. H.T. and E.H.S. wrote the manuscript, and all authors read and commented on the manuscript.

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Correspondence to Chunfeng Zhang or Jia Zhu or Hairen Tan.

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Supplementary Figs. 1–30, Tables 1–4, Note 1 and refs. 1–4.

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Lin, R., Xiao, K., Qin, Z. et al. Monolithic all-perovskite tandem solar cells with 24.8% efficiency exploiting comproportionation to suppress Sn(ii) oxidation in precursor ink. Nat Energy 4, 864–873 (2019).

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