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Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes

Abstract

In perovskite solar cells, the interfaces between the perovskite and charge-transporting layers contain high concentrations of defects (about 100 times that within the perovskite layer), specifically, deep-level defects, which substantially reduce the power conversion efficiency of the devices1,2,3. Recent efforts to reduce these interfacial defects have focused mainly on surface passivation4,5,6. However, passivating the perovskite surface that interfaces with the electron-transporting layer is difficult, because the surface-treatment agents on the electron-transporting layer may dissolve while coating the perovskite thin film. Alternatively, interfacial defects may not be a concern if a coherent interface could be formed between the electron-transporting and perovskite layers. Here we report the formation of an interlayer between a SnO2 electron-transporting layer and a halide perovskite light-absorbing layer, achieved by coupling Cl-bonded SnO2 with a Cl-containing perovskite precursor. This interlayer has atomically coherent features, which enhance charge extraction and transport from the perovskite layer, and fewer interfacial defects. The existence of such a coherent interlayer allowed us to fabricate perovskite solar cells with a power conversion efficiency of 25.8 per cent (certified 25.5 per cent)under standard illumination. Furthermore, unencapsulated devices maintained about 90 per cent of their initial efficiency even after continuous light exposure for 500 hours. Our findings provide guidelines for designing defect-minimizing interfaces between metal halide perovskites and electron-transporting layers.

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Fig. 1: Interlayer formation from Cl-bSO and Cl-cPP.
Fig. 2: Local geometric environments around the Sn atoms in the SnO2 electrodes, before and after applying the perovskite precursor solution.
Fig. 3: Two-dimensional GI-WAXD patterns, HR-TEM and photoluminescence after applying Cl-cPP on Cl-bSO and SnO2.
Fig. 4: Performance of PSCs based on various electrodes.

Data availability

The data that support the findings of this study are available from the corresponding authors on reasonable request.

Code availability

The code used for this study is available from the corresponding authors on reasonable request.

References

  1. 1.

    Ni, Z. et al. Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells. Science 367, 1352–1358 (2020).

    ADS  CAS  Article  Google Scholar 

  2. 2.

    Ono, L. K., Liu, S. & Qi, Y. Reducing detrimental defects for high-performance metal halide perovskite solar cells. Angew. Chem. Int. Ed. 59, 6676–6698 (2020).

    CAS  Article  Google Scholar 

  3. 3.

    Schulz, P., Cahen, D. & Kahn, A. Halide perovskites: is it all about the interfaces? Chem. Rev. 119, 3349–3417 (2019).

    CAS  Article  Google Scholar 

  4. 4.

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

    ADS  CAS  Article  Google Scholar 

  5. 5.

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

    ADS  CAS  Article  Google Scholar 

  6. 6.

    Azmi, R. et al. Shallow and deep trap state passivation for low-temperature processed perovskite solar cells. ACS Energy Lett. 5, 1396–1403 (2020).

    CAS  Article  Google Scholar 

  7. 7.

    Jeon, N. J. et al. Compositional engineering of perovskite materials for high-performance solar cells. Nature 517, 476–480 (2015).

    ADS  CAS  Article  Google Scholar 

  8. 8.

    Hui, W. et al. Stabilizing black-phase formamidinium perovskite formation at room temperature and high humidity. Science 371, 1359–1364 (2021).

    ADS  CAS  Article  Google Scholar 

  9. 9.

    Jeong, M. J., Yeom, K. M., Kim, S. J., Jung, E. H. & Noh, J. H. Spontaneous interface engineering for dopant-free poly(3-hexylthiophene) perovskite solar cells with efficiency over 24%. Energy Environ. Sci. (2021).

  10. 10.

    Yoo, J. J. et al. Efficient perovskite solar cells via improved carrier management. Nature 590, 587–593 (2021).

    ADS  CAS  Article  Google Scholar 

  11. 11.

    Jeong, J. et al. Pseudo-halide anion engineering for α-FAPbI3 perovskite solar cells. Nature 592, 381–385 (2021).

    ADS  CAS  Article  Google Scholar 

  12. 12.

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

    ADS  CAS  Article  Google Scholar 

  13. 13.

    Jiang, Q. et al. Enhanced electron extraction using SnO2 for high-efficiency planar-structure HC(NH2)2PbI3-based perovskite solar cells. Nat. Energy 2, 16177 (2017).

    ADS  CAS  Article  Google Scholar 

  14. 14.

    Jung, K.-H., Seo, J.-Y., Lee, S., Shin, H. & Park, N.-G. Solution-processed SnO2 thin film for a hysteresis-free planar perovskite solar cell with a power conversion efficiency of 19.2%. J. Mater. Chem. A 5, 24790–24803 (2017).

    CAS  Article  Google Scholar 

  15. 15.

    Jeong, S., Seo, S., Park, H. & Shin, H. Atomic layer deposition of a SnO2 electron-transporting layer for planar perovskite solar cells with a power conversion efficiency of 18.3%. Chem. Commun. 55, 2433–2436 (2019).

    CAS  Article  Google Scholar 

  16. 16.

    Anaraki, E. H. et al. Highly efficient and stable planar perovskite solar cells by solution-processed tin oxide. Energy Environ. Sci. 9, 3128–3134 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    McGott, D. L. et al. 3D/2D passivation as a secret to success for polycrystalline thin-film solar cells. Joule 5, 1057–1073 (2021).

    CAS  Article  Google Scholar 

  18. 18.

    Aydin, E., De Bastiani, M. & De Wolf, S. Defect and contact passivation for perovskite solar cells. Adv. Mater. 31, e1900428 (2019).

    Article  Google Scholar 

  19. 19.

    Li, Z. et al. Spontaneous interface ion exchange: passivating surface defects of perovskite solar cells with enhanced photovoltage. Adv. Energy Mater. 9, 1902142 (2019).

    ADS  CAS  Article  Google Scholar 

  20. 20.

    Min, H. et al. Efficient, stable solar cells by using inherent bandgap of α-phase formamidinium lead iodide. Science 366, 749–753 (2019).

    ADS  CAS  Article  Google Scholar 

  21. 21.

    Yoon, S. M. et al. Surface engineering of ambient-air-processed cesium lead triiodide layers for efficient solar cells. Joule 5, 183–196 (2021).

    CAS  Article  Google Scholar 

  22. 22.

    Tao, S. et al. Absolute energy level positions in tin- and lead-based halide perovskites. Nat. Commun. 10, 2560 (2019).

    ADS  Article  Google Scholar 

  23. 23.

    Khan, J. et al. Low-temperature-processed SnO2–Cl for efficient PbS quantum-dot solar cells via defect passivation. J. Mater. Chem. A 5, 17240–17247 (2017).

    CAS  Article  Google Scholar 

  24. 24.

    Ke, W. et al. Low-temperature solution-processed tin oxide as an alternative electron transporting layer for efficient perovskite solar cells. J. Am. Chem. Soc. 137, 6730–6733 (2015).

    CAS  Article  Google Scholar 

  25. 25.

    Dong, Q., Shi, Y., Zhang, C., Wu, Y. & Wang, L. Energetically favored formation of SnO2 nanocrystals as electron transfer layer in perovskite solar cells with high efficiency exceeding 19%. Nano Energy 40, 336–344 (2017).

    CAS  Article  Google Scholar 

  26. 26.

    Kılıç, Ç. & Zunger, A. Origins of coexistence of conductivity and transparency in SnO2. Phys. Rev. Lett. 88, 095501 (2002).

    ADS  Article  Google Scholar 

  27. 27.

    Kim, M. et al. Methylammonium chloride induces intermediate phase stabilization for efficient perovskite solar cells. Joule 3, 2179–2192 (2019).

    CAS  Article  Google Scholar 

  28. 28.

    Hao, F., Stoumpos, C. C., Cao, D. H., Chang, R. P. H. & Kanatzidis, M. G. Lead-free solid-state organic–inorganic halide perovskite solar cells. Nat. Photon. 8, 489–494 (2014).

    ADS  CAS  Article  Google Scholar 

  29. 29.

    Kamat, P. V., Bisquert, J. & Buriak, J. Lead-free perovskite solar cells. ACS Energy Lett. 2, 904–905 (2017).

    CAS  Article  Google Scholar 

  30. 30.

    Hailey, A. K., Hiszpanski, A. M., Smilgies, D.-M. & Loo, Y.-L. The diffraction pattern calculator (DPC) toolkit: a user-friendly approach to unit-cell lattice parameter identification of two-dimensional grazing-incidence wide-angle X-ray scattering data. J. Appl. Cryst. 47, 2090–2099 (2014).

    CAS  Article  Google Scholar 

  31. 31.

    Weller, M. T., Weber, O. J., Frost, J. M. & Walsh, A. Cubic perovskite structure of black formamidinium lead iodide, α-[HC(NH2)2]PbI3, at 298 K. J. Phys. Chem. Lett. 6, 3209–3212 (2015).

    CAS  Article  Google Scholar 

  32. 32.

    Alberti, A. et al. Pb clustering and PbI2 nanofragmentation during methylammonium lead iodide perovskite degradation. Nat. Commun. 10, 2196 (2019).

    ADS  Article  Google Scholar 

  33. 33.

    Yang, G. et al. Effective carrier-concentration tuning of SnO2 quantum dot electron-selective layers for high-performance planar perovskite solar cells. Adv. Mater. 30, 1706023 (2018).

    Article  Google Scholar 

  34. 34.

    Lee, J.-W. et al. Solid-phase hetero epitaxial growth of α-phase formamidinium perovskite. Nat. Commun. 11, 5514 (2020).

    ADS  CAS  Article  Google Scholar 

  35. 35.

    Krückemeier, L., Krogmeier, B., Liu, Z., Rau, U. & Kirchartz, T. Understanding transient photoluminescence in halide perovskite layer stacks and solar cells. Adv. Energy Mater. 11, 2003489 (2021).

    Article  Google Scholar 

  36. 36.

    Kim, G., Min, H., Lee, K. S., Yoon, S. M. & Seok, S. I. Impact of strain relaxation on performance of α-formamidinium lead iodide perovskite solar cells. Science 370, 108–112 (2020).

    ADS  CAS  Article  Google Scholar 

  37. 37.

    Chen, S. et al. Spatial distribution of lead iodide and local passivation on organo-lead halide perovskite. ACS Appl. Mater. Interfaces 9, 6072–6078 (2017).

    CAS  Article  Google Scholar 

  38. 38.

    Khenkin, M. V. et al. Consensus statement for stability assessment and reporting for perovskite photovoltaics based on ISOS procedures. Nat. Energy 5, 35–49(2020).

    ADS  Article  Google Scholar 

  39. 39.

    Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

    ADS  CAS  Article  Google Scholar 

  40. 40.

    Tkatchenko, A. & Scheffler, M. Accurate molecular van der Waals interactions from ground-state electron density and free-atom reference data. Phys. Rev. Lett. 102, 073005 (2009).

    ADS  Article  Google Scholar 

  41. 41.

    Kresse, G. & Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 6, 15–50 (1996).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

This work was supported by the Basic Science Research Program (NRF-2018R1A3B1052820) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (MSIP). This work was also supported by the Defense Challengeable Future Technology Program of the Agency for Defense Development, Republic of Korea, a brand project (1.200030.01) of UNIST, and Alchemist Project (2019309101046). We thank UCRF (UNIST central research facilities) for use of equipment and the beamline staff at Pohang Accelerator Laboratory.

Author information

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Authors

Contributions

S.I.S., H.M. and D.Y.L. conceived the work and designed the experiment. H.M. and D.Y.L. fabricated the PSCs with various electrodes and characterized the perovskite films. Junu Kim conducted the theoretical simulations, with supervision from K.S.K. K.S.L. measured the thermally stimulated current. Jongbeom Kim and G.K. carried out the model PSC fabrication and SEM measurements. M.J.P. prepared the SnO2 colloids. Y.K.K. conducted HR-TEM. T.J.S. conducted and interpreted the GI-WAXD. M.G.K. measured and interpreted the XAFS. S.I.S. and H.M. wrote the manuscript, with all authors contributing feedback and comments. S.I.S. directed and supervised the study.

Corresponding authors

Correspondence to Min Gyu Kim, Tae Joo Shin or Sang Il Seok.

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The authors declare no competing interests.

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Extended data figures and tables

Extended Data Fig. 1 Cl- ion contents analysed by ToF-SIMS.

The black line is the analysis result for the Cl ions on the thin film obtained after spin coating with the SnCl2.2H2O solution dissolved in ethanol and then heat treatment at 190 °C for 1 h. The blue line is the result of Clion analysis on a thin film obtained by spin coating a SnO2 colloid generated by heat treatment at 70 °C for 30 min after dissolving 0.1 mol of SnCl4 in deionised water.

Extended Data Fig. 2 Depth profiles analysed by ToF-SIMS with a PSC fabricated using a commercial SnO2 colloids as electron-transporting layer.

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Extended Data Fig. 3 DFT simulation of the formation of the interlayer between the perovskite and SnO2.

a, back side view, b, right side view, and c, left side view of Fig. 1d in (a) 3-dimensional and (b) 2-dimensional shapes. [Pb (black), I (purple), Cl (green), C (brown), N (light blue), H (white), Sn (dark blue), and O (red)].

Extended Data Fig. 4 Theoretical simulation for the formation of an interlayer between Cl-TiO2 and Cl-cPP.

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Extended Data Fig. 5 Wavelet transform of correlation between the Fourier-transformed peaks with k-space data for local geometric environments around Sn of SnO2, which was annealed at 120 °C for 1 h using a perovskite precursor without Cl- ions coated on a Cl-bSO electrode.

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Extended Data Fig. 6 Simulation of the diffraction peaks by a, FAPbI3 (a = 6.351 Å, Pm-3m (#221) space group) and b, PbI2 (a = b = 4.555 Å, c = 6.964 Å, P-3m1 (#164) space group) using the Diffraction Pattern Calculator (DPC) toolkit.

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Extended Data Fig. 7 1D GI-WAXD profiles for the  out-of-plane (qz-cut; along qxy = 0) and in-plane (qxy-cut; along qz = 0).

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Extended Data Fig. 8 2D GI-WAXD image focused on the interlayer structure.

Crystallographic information was empirically derived from the diffraction patterns. The crystal structure of this interlayer can be assumed to be tetragonal with a = b = 5.56 Å, c = 5.29 Å. If the (001) crystal plane is oriented parallel to the substrate, the observed characteristic diffraction peaks belong to (11l) and (22l) families.

Extended Data Fig. 9 Steady-state PLs of perovskites with and without the SnO2 or TiO2 electrode on the glass substrate.

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Extended Data Fig. 10 Time-resolved photoluminescence (TRPL) spectra after excitation at 520 nm (P-C-520M) with repetition rate of 200 kHz and a fluence of 34 nJ cm-2 per pulse for perovskite films on various ETLs coated on FTO substrates and perovskite without ETL on glass.

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Extended Data Table 1 All parameters determined from the J-V curve of Fig. 4c.

Supplementary information

Supplementary Information

This file contains Supplementary Figs. 19 and Supplementary Table 1.

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Min, H., Lee, D.Y., Kim, J. et al. Perovskite solar cells with atomically coherent interlayers on SnO2 electrodes. Nature 598, 444–450 (2021). https://doi.org/10.1038/s41586-021-03964-8

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