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Stabilization of formamidinium lead triiodide α-phase with isopropylammonium chloride for perovskite solar cells

A Publisher Correction to this article was published on 06 May 2021

This article has been updated


Formamidinium lead triiodide (FAPbI3) perovskite solar cells (PSCs) are mainly fabricated by sequentially coating lead iodide and formamidinium iodide, or by coating a solution in which all components are dissolved in one solvent (one-pot process). The PSCs produced by both processes exhibited similar efficiencies; however, their long-term stabilities were notably different. We concluded that the major reason for this behaviour is the stabilization of the α-FAPbI3 phase by isopropylammonium cations produced by the chemical reaction between isopropyl alcohol, used as solvent, and methylammonium chloride, added during the process. On this basis, we fabricated PSCs by adding isopropylammonium chloride to the perovskite precursor solution for the one-pot process and achieved a certified power conversion efficiency of 23.9%. Long-term operational current density–voltage measurements (one sweep every 84 min under 1-Sun irradiation in nitrogen atmosphere) showed that the as-fabricated device with an initial efficiency of approximately 20% recorded an efficiency of about 23% after 1,000 h that gradually degraded to about 22% after an additional 1,000 h.

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Fig. 1: Monitoring the formation of FAPbI3 films.
Fig. 2: HR-TEM characterization of the FAPbI3 films.
Fig. 3: HR-XPS chemical analysis of the three FAPbI3 perovskite thin films.
Fig. 4: Surface, crystal and optophysical properties.
Fig. 5: Computational investigation and PSC performance.

Data availability

All data generated or analysed during this study are included in the published article and its Supplementary Information. Source data are provided with this paper.

Change history


  1. 1.

    Saliba, M. et al. Cesium-containing triple cation perovskite solar cells: improved stability, reproducibility and high efficiency. Energy Environ. Sci. 9, 1989–1997 (2016).

    Article  Google Scholar 

  2. 2.

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

    Article  Google Scholar 

  3. 3.

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

    Article  Google Scholar 

  4. 4.

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

    Article  Google Scholar 

  5. 5.

    Kim, G. et al. Impact of strain relaxation on performance of α-formamidinium lead iodide perovskite solar cells. Science 370, 108–112 (2020).

    Article  Google Scholar 

  6. 6.

    Bai, S. et al. Planar perovskite solar cells with long-term stability using ionic liquid additives. Nature 571, 245–250 (2019).

    Article  Google Scholar 

  7. 7.

    Yang, W. S. et al. Iodide management in formamidinium-lead-halide–based perovskite layers for efficient solar cells. Science 356, 1376–1379 (2017).

    Article  Google Scholar 

  8. 8.

    Burschka, J. et al. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499, 316–319 (2013).

    Article  Google Scholar 

  9. 9.

    Wang, X. et al. Improving efficiency of planar hybrid CH3NH3PbI3−xClx perovskite solar cells by isopropanol solvent treatment. Org. Electron. 24, 205–211 (2015).

    Article  Google Scholar 

  10. 10.

    Li, Z. et al. Extrinsic ion migration in perovskite solar cells. Energy Environ. Sci. 10, 1234–1242 (2017).

    Article  Google Scholar 

  11. 11.

    Cao, J. et al. Identifying the molecular structures of intermediates for optimizing the fabrication of high-quality perovskite films. J. Am. Chem. Soc. 138, 9919–9926 (2016).

    Article  Google Scholar 

  12. 12.

    Petrov, A. A. et al. Crystal structure of DMF-intermediate phases uncovers the link between CH3NH3PbI3 morphology and precursor stoichiometry. J. Phys. Chem. C. 121, 20739–20743 (2017).

    Article  Google Scholar 

  13. 13.

    Gratia, P. et al. The many faces of mixed ion perovskites: unraveling and understanding the crystallization process. ACS Energy Lett. 2, 2686–2693 (2017).

    Article  Google Scholar 

  14. 14.

    Prasanna, R. et al. Design of low bandgap tin–lead halide perovskite solar cells to achieve thermal, atmospheric and operational stability. Nat. Energy 4, 939–947 (2019).

    Article  Google Scholar 

  15. 15.

    Kim, J. et al. Unveiling the relationship between the perovskite precursor solution and the resulting device performance. J. Am. Chem. Soc. 142, 6251–6260 (2020).

    Article  Google Scholar 

  16. 16.

    Jain, V., Biesinger, M. C. & Linford, M. R. The Gaussian-Lorentzian sum, product, and convolution (Voigt) functions in the context of peak fitting X-ray photoelectron spectroscopy (XPS) narrow scans. Appl. Surf. Sci. 447, 548–553 (2018).

    Article  Google Scholar 

  17. 17.

    Roghabadi, F. A., Ahmadi, V. & Aghmiuni, K. O. Organic–inorganic halide perovskite formation: in situ dissociation of cation halide and metal halide complexes during crystal formation. J. Phys. Chem. C. 121, 13532–13538 (2017).

    Article  Google Scholar 

  18. 18.

    Jacobsson, T. J. et al. Unreacted PbI2 as a double-edged sword for enhancing the performance of perovskite solar cells. J. Am. Chem. Soc. 138, 10331–10343 (2016).

    Article  Google Scholar 

  19. 19.

    Inamura, K., Inoue, Y., Ikeda, S. & Kishi, K. X-ray photoelectron spectroscopic study for the adsorption and the decomposition of alkylamines on nickel. Surf. Sci. 155, 173–186 (1985).

    Article  Google Scholar 

  20. 20.

    Lee, M. V. et al. Transamidation of dimethylformamide during alkylammonium lead triiodide film formation for perovskite solar cells. J. Mater. Res. 32, 45–55 (2017).

    Article  Google Scholar 

  21. 21.

    Appiagyei, B., Bhatia, S., Keeney, G. L., Dolmetsch, T. & Jackson, J. E. Electroactivated alkylation of amines with alcohols via both direct and indirect borrowing hydrogen mechanisms. Green Chem. 22, 860–869 (2020).

    Article  Google Scholar 

  22. 22.

    Bhän, S. et al. The catalytic amination of alcohols. ChemCatChem 3, 1853–1864 (2011).

    Article  Google Scholar 

  23. 23.

    Kelefiotis-Stratidakis, P., Tyrikos-Ergas, T. & Pavlidis, I. V. The challenge of using isopropylamine as an amine donor in transaminase catalysed reactions. Org. Biomol. Chem. 17, 1634–1642 (2019).

    Article  Google Scholar 

  24. 24.

    Li, S. et al. Amination of isopropanol to isopropylamine over a highly basic and active Ni/LaAlSiO catalyst. J. Catal. 350, 141–148 (2017).

    Article  Google Scholar 

  25. 25.

    Turner, W. D. & Howald, A. M. Methyl amines from methyl alcohol and ammonium cloride. J. Am. Chem. Soc. 42, 2663–2665 (1920).

    Article  Google Scholar 

  26. 26.

    Madenwald, F. A., Henke, C. O. & Brown, O. W. Catalytic activity of lead. J. Phys. Chem. 31, 862–866 (1927).

    Article  Google Scholar 

  27. 27.

    Xue, C., Li, J., Lee, J. P., Zhang, P. & Wu, J. Continuous amination of aryl/heteroaryl halides using aqueous ammonia in a Teflon AF-2400 tube-in-tube micro-flow reactor. React. Chem. Eng. 4, 346–350 (2019).

    Article  Google Scholar 

  28. 28.

    Singh, A., Gupta, S. & Khurana, J. M. Zinc chloride mediated nucleophilic substitution: amination and thioetherification of alcohols at room temperature. Org. Prep. Proced. Int. 52, 110–119 (2020).

    Article  Google Scholar 

  29. 29.

    Ferreira, A. C. et al. Elastic softness of hybrid lead halide perovskites. Phys. Rev. Lett. 121, 085502 (2018).

    Article  Google Scholar 

  30. 30.

    Chen, Y. et al. Strain engineering and epitaxial stabilization of halide perovskites. Nature 577, 209–215 (2020).

    Article  Google Scholar 

  31. 31.

    Jung, M., Shin, T. J., Seo, J., Kim, G. & Seok, S. I. Structural features and their functions in surfactant-armoured methylammonium lead iodide perovskites for highly efficient and stable solar cells. Energy Environ. Sci. 11, 2188–2197 (2018).

    Article  Google Scholar 

  32. 32.

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

    Article  Google Scholar 

  33. 33.

    Lee, J.-W. et al.2D perovskite stabilized phase-pure formamidinium perovskite solar cells. Nat. Commun. 9, 3021 (2018).

    Article  Google Scholar 

  34. 34.

    Li, Y. et al. Mixed cation FAxPEA1–xPbI3 with enhanced phase and ambient stability toward high-performance perovskite solar cells. Adv. Energy Mater. 7, 1601307 (2017).

    Article  Google Scholar 

  35. 35.

    Nemnes, G. A. et al. How measurement protocols influence the dynamic J-V characteristics of perovskite solar cells: theory and experiment. Sol. Energy 173, 976–983 (2018).

    Article  Google Scholar 

  36. 36.

    Bastos, J. P. et al. Light-induced degradation of perovskite solar cells: the influence of 4-tert-butyl pyridine and gold. Adv. Energy Mater. 8, 1800554 (2018).

    Article  Google Scholar 

  37. 37.

    Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953 (1994).

    Article  Google Scholar 

  38. 38.

    Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758 (1999).

    Article  Google Scholar 

  39. 39.

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

    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).

    Article  Google Scholar 

  41. 41.

    Chen, T. et al. Entropy-driven structural transition and kinetic trapping in formamidinium lead iodide perovskite. Sci. Adv. 2, e1601650 (2016).

    Article  Google Scholar 

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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). B.-w.P. acknowledges financial support from the Creative-Challenge Research Program (NRF-2020R1I1A1A01063868). T.J.S. acknowledges financial support under CAP-18-05-KAERI. This work was also supported by a brand project (1.210037.01) of UNIST. Experiments at the PLS-II 6D and 10A2 beamlines were supported in part by MSIT and POSTECH. We thank S. Y. Lee, J. H. Park, I. Choi, G. A. Lee, J. H. Lee, H. J. Mun, D. H. Lee and S.-P. Han of UCRF for their support in powder XRD, FIB sampling, HR-TEM, FESEM, GI-WAXD, ToF-SIMS and NMR analyses.

Author information




B.-w.P., H.W.K. and S.I.S. conceived this work. B.-w.P. and H.W.K. prepared the perovskite thin layers and solar cells and interpreted all data from the analyses. Y.L. and D.Y.L. fabricated the materials and devices for the perovskite solar cells. G.K. and K.-j.K. conducted the XPS investigation. M.G.K. performed the chemical analysis. Y.K.K. carried out HR-TEM analysis. J.I. calculated the formation energy of iPAmHCl–FAPbI3. T.J.S. guided the XPS and GI-WAXD investigations and contributed to their interpretation. B.-w.P. and S.I.S. wrote the manuscript.

Corresponding authors

Correspondence to Tae Joo Shin or Sang Il Seok.

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The authors declare no competing interests.

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Peer review information Nature Energy thanks Caterina Ducati 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. 1–25, Tables 1–3 and references.

Source data

Source Data Fig. 5

Photovoltaic parameters of the solar cells shown in the Fig. 5b.

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Park, Bw., Kwon, H.W., Lee, Y. et al. Stabilization of formamidinium lead triiodide α-phase with isopropylammonium chloride for perovskite solar cells. Nat Energy 6, 419–428 (2021).

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