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:

Local nanoscale phase impurities are degradation sites in halide perovskites

Nature volume 607, pages 294–300 (2022)Cite this article

Subjects

Abstract

Understanding the nanoscopic chemical and structural changes that drive instabilities in emerging energy materials is essential for mitigating device degradation. The power conversion efficiency of halide perovskite photovoltaic devices has reached 25.7 per cent in single-junction and 29.8 per cent in tandem perovskite/silicon cells1,2, yet retaining such performance under continuous operation has remained elusive3. Here we develop a multimodal microscopy toolkit to reveal that in leading formamidinium-rich perovskite absorbers, nanoscale phase impurities, including hexagonal polytype and lead iodide inclusions, are not only traps for photoexcited carriers, which themselves reduce performance4,5, but also, through the same trapping process, are sites at which photochemical degradation of the absorber layer is seeded. We visualize illumination-induced structural changes at phase impurities associated with trap clusters, revealing that even trace amounts of these phases, otherwise undetected with bulk measurements, compromise device longevity. The type and distribution of these unwanted phase inclusions depends on the film composition and processing, with the presence of polytypes being most detrimental for film photo-stability. Importantly, we reveal that both performance losses and intrinsic degradation processes can be mitigated by modulating these defective phase impurities, and demonstrate that this requires careful tuning of local structural and chemical properties. This multimodal workflow to correlate the nanoscopic landscape of beam-sensitive energy materials will be applicable to a wide range of semiconductors for which a local picture of performance and operational stability has yet to be established.

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

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

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

Fig. 1: Trap clusters are sites at which local degradation seeds.
Fig. 2: Light-induced degradation occurs at phase impurities in Cs0.05FA0.78MA0.17Pb(I0.83Br0.17)3 thin films, ascertained by monitoring structural changes after illumination.
Fig. 3: Film composition and passivation modulates the nature and activity of phase impurities in FA-rich perovskites and the resulting photo-stability.

Similar content being viewed by others

Data availability

The data that support the findings of this study are available at https://doi.org/10.17863/CAM.85310 or from the corresponding authors upon request.

References

  1. Best research-cell efficiency chart. Best research-cell efficiency chart. NREL https://www.nrel.gov/pv/cell-efficiency.html (2022).

  2. Jošt, M., Kegelmann, L., Korte, L. & Albrecht, S. Monolithic perovskite tandem solar cells: a review of the present status and advanced characterization methods toward 30% efficiency. Adv. Energy Mater. 10, 1904102 (2020).

    Article  Google Scholar 

  3. Li, N., Niu, X., Chen, Q. & Zhou, H. Towards commercialization: the operational stability of perovskite solar cells. Chem. Soc. Rev. 49, 8235–8286 (2020).

    Article  CAS  PubMed  Google Scholar 

  4. Miller, O. D., Yablonovitch, E. & Kurtz, S. R. Strong internal and external luminescence as solar cells approach the Shockley–Queisser limit. IEEE J. Photovolt. 2, 303–311 (2012).

    Article  Google Scholar 

  5. Doherty, T. A. S. et al. Performance-limiting nanoscale trap clusters at grain junctions in halide perovskites. Nature 580, 360–366 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  6. Orri, J. F. et al. Unveiling the interaction mechanisms of electron and X-ray radiation with halide perovskite semiconductors using scanning nano-probe diffraction. Adv. Mater. 34, 2200383 (2022).

    Article  Google Scholar 

  7. 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  CAS  PubMed  PubMed Central  Google Scholar 

  8. Al-Ashouri, A. et al. Monolithic perovskite/silicon tandem solar cell with >29% efficiency by enhanced hole extraction. Science 370, 1300–1309 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  9. Andaji‐Garmaroudi, Z., Anaya, M., Pearson, A. J. & Stranks, S. D. Photobrightening in lead halide perovskites: observations, mechanisms, and future potential. Adv. Energy Mater. 10, 1903109 (2020).

    Article  ADS  Google Scholar 

  10. Tress, W. et al. Interpretation and evolution of open-circuit voltage, recombination, ideality factor and subgap defect states during reversible light-soaking and irreversible degradation of perovskite solar cells. Energy Environ. Sci. 11, 151–165 (2018).

    Article  CAS  Google Scholar 

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

    Article  ADS  PubMed  PubMed Central  Google Scholar 

  12. Lin, Y.-H. et al. A piperidinium salt stabilizes efficient metal-halide perovskite solar cells. Science 369, 96–102 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  13. Shao, S. & Loi, M. A. The role of the interfaces in perovskite solar cells. Adv. Mater. Interfaces 7, 1901469 (2020).

    Article  CAS  Google Scholar 

  14. Kosar, S. et al. Unraveling the varied nature and roles of defects in hybrid halide perovskites with time-resolved photoemission electron microscopy. Energy Environ. Sci. 14, 6320–6328 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Palosz, B. The structure of PbI2 polytypes 2H and 4H: a study of the 2H–4H transition. J. Phys. Condens. Matter 2, 5285–5295 (1990).

    Article  ADS  CAS  Google Scholar 

  16. Meggiolaro, D. et al. Iodine chemistry determines the defect tolerance of lead-halide perovskites. Energy Environ. Sci. 11, 702–713 (2018).

    Article  CAS  Google Scholar 

  17. Motti, S. G. et al. Controlling competing photochemical reactions stabilizes perovskite solar cells. Nat. Photon. 13, 532–539 (2019).

    Article  ADS  CAS  Google Scholar 

  18. Samu, G. F. et al. Electrochemical hole injection selectively expels iodide from mixed halide perovskite films. J. Am. Chem. Soc. 141, 10812–10820 (2019).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  19. Frolova, L. A. et al. Reversible Pb2+/Pb0 and I−/I3− redox chemistry drives the light-induced phase segregation in all-inorganic mixed halide perovskites. Adv. Energy Mater. 11, 2002934 (2021).

    Article  CAS  Google Scholar 

  20. Azpiroz, J. M., Mosconi, E., Bisquert, J. & Angelis, F. D. Defect migration in methylammonium lead iodide and its role in perovskite solar cell operation. Energy Environ. Sci. 8, 2118–2127 (2015).

    Article  CAS  Google Scholar 

  21. Baltog, I., Piticu, I., Constantinescu, M., Ghita, C. & Ghita, L. Optical investigations of PbI2 single crystals after thermal treatment. Phys. Status Solidi A 52, 103–110 (1979).

    Article  ADS  CAS  Google Scholar 

  22. Albrecht, M. G. & Green, M. The kinetics of the photolysis of thin films of lead iodide. J. Phys. Chem. Solids 38, 297–306 (1977).

    Article  ADS  CAS  Google Scholar 

  23. Juarez-Perez, E. J. et al. Photodecomposition and thermal decomposition in methylammonium halide lead perovskites and inferred design principles to increase photovoltaic device stability. J. Mater. Chem. A 6, 9604–9612 (2018).

    Article  CAS  Google Scholar 

  24. Cho, H. et al. Overcoming the electroluminescence efficiency limitations of perovskite light-emitting diodes. Science 350, 1222–1225 (2015).

    Article  ADS  CAS  PubMed  Google Scholar 

  25. Tumen‐Ulzii, G. et al. Detrimental effect of unreacted PbI2 on the long-term stability of perovskite solar cells. Adv. Mater. 32, 1905035 (2020).

    Article  Google Scholar 

  26. Feldmann, S. et al. Photodoping through local charge carrier accumulation in alloyed hybrid perovskites for highly efficient luminescence. Nat. Photon. 14, 123–128 (2020).

    Article  ADS  CAS  Google Scholar 

  27. Chiang, Y.-H., Anaya, M. & Stranks, S. D. Multisource vacuum deposition of methylammonium-free perovskite solar cells. ACS Energy Lett. 5, 2498–2504 (2020).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  28. Beal, R. E. et al. Structural origins of light-induced phase segregation in organic–inorganic halide perovskite photovoltaic materials. Matter 2, 207–219 (2020).

    Article  Google Scholar 

  29. Li, N. et al. Microscopic degradation in formamidinium-cesium lead iodide perovskite solar cells under operational stressors. Joule 4, 1743–1758 (2020).

    Article  CAS  Google Scholar 

  30. Doherty, T. A. S. et al. Stabilized tilted-octahedra halide perovskites inhibit local formation of performance-limiting phases. Science 374, 1598–1605 (2021).

    Article  ADS  CAS  PubMed  Google Scholar 

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

    Article  ADS  CAS  PubMed  Google Scholar 

  32. Brenes, R. et al. Metal halide perovskite polycrystalline films exhibiting properties of single crystals. Joule 1, 155–167 (2017).

    Article  CAS  Google Scholar 

  33. Godding, J. S. W. et al. Oxidative passivation of metal halide perovskites. Joule 3, 2716–2731 (2019).

    Article  CAS  Google Scholar 

  34. Lu, H. et al. Vapor-assisted deposition of highly efficient, stable black-phase FAPbI3 perovskite solar cells. Science 370, eabb8985 (2020).

    Article  ADS  CAS  PubMed  Google Scholar 

  35. Jones, T. W. et al. Lattice strain causes non-radiative losses in halide perovskites. Energy Environ. Sci. 12, 596–606 (2019).

    Article  CAS  Google Scholar 

  36. Rotermund, F. & Petrov, V. Generation of the fourth harmonic of a femtosecond Ti:sapphire laser. Opt. Lett. 23, 1040–1042 (1998).

    Article  ADS  CAS  PubMed  Google Scholar 

  37. Rothmann, M. U. et al. Atomic-scale microstructure of metal halide perovskite. Science 370, eabb5940 (2020).

    Article  CAS  PubMed  Google Scholar 

  38. Guinier, A. et al. Nomenclature of polytype structures. Report of the International Union of Crystallography Ad hoc Committee on the Nomenclature of Disordered, Modulated and Polytype Structures. Acta Crystallogr. A 40, 399–404 (1984).

    Article  Google Scholar 

  39. Johnstone, D. N. et al. pyxem/pyxem: pyxem 0.13.0. Zenodo https://doi.org/10.5281/zenodo.4436723 (2021).

  40. Quinn, P. D. et al. The hard X-ray nanoprobe beamline at Diamond Light Source. J. Synchrotron Radiat. 28, 1006–1013 (2021).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  41. Basham, M. et al. Data Analysis WorkbeNch (DAWN). J. Synchrotron Radiat. 22, 853–858 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  42. de la Peña, F. et al. hyperspy/hyperspy v1.4.1. Zenodo https://doi.org/10.5281/zenodo.1469364 (2018).

  43. Jones, G. O. & Thomas, P. A. Investigation of the structure and phase transitions in the novel A-site substituted distorted perovskite compound Na0.5Bi0.5TiO3. Acta Crystallogr. B 58, 168–178 (2002).

    Article  CAS  PubMed  Google Scholar 

  44. Woodward, D. I. & Reaney, I. M. Electron diffraction of tilted perovskites. Acta Crystallogr. B 61, 387–399 (2005).

    Article  PubMed  Google Scholar 

  45. Reference Air Mass 1.5 Spectra. NREL https://www.nrel.gov/grid/solar-resource/spectra-am1.5.html (2022).

  46. deQuilettes, D. W. et al. Photo-induced halide redistribution in organic-inorganic perovskite films. Nat. Commun. 7, 11683 (2016).

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

Download references

Acknowledgements

S.M. acknowledges funding from an Engineering and Physical Sciences Research Council (EPSRC) studentship and support from the Japan Society for the Promotion of Science (JSPS) Summer Fellowship Programme. T.A.S.D. acknowledges the support of a National University of Ireland Travelling Studentship and an Oppenheimer Research Fellowship. S.D.S. acknowledges the Royal Society and Tata Group (UF150033). The work has received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme (HYPERION - grant agreement number 756962). Z.A.-G. acknowledges funding from a Winton Studentship and an ICON Studentship from the Lloyd’s Register Foundation. Y.H.-C. thanks the Cambridge Trust for a studentship and acknowledges the Taiwan Cambridge Trust and Rank Prize. We acknowledge the EPSRC (EP/R023980/1, EP/V012932/1, EP/T02030X/1 and EP/S030638/1) for funding. K.F. acknowledges a George and Lilian Schiff Studentship, a Winton Studentship, a EPSRC studentship, a Cambridge Trust Scholarship and a Robert Gardiner Scholarship. M.A. acknowledges funding from the Marie Skłodowska-Curie actions (grant agreement number 841386) under the European Union’s Horizon 2020 research and innovation programme. K.W.P.O. acknowledges an EPSRC studentship. A.N.I. acknowledges a scholarship from the British Spanish Society. K.G. acknowledges support from the Polish Ministry of Science and Higher Education within the Mobilnosc Plus program (grant number 1603/MOB/V/2017/0). P.A.M. thanks the EPSRC for funding under grant numbers EP/R008779/1 and EP/V007750/1, and the European Union Horizon 2020 research and innovation programme (ESTEEM3): 823717. A.J.W., S.K. and K.M.D. acknowledge that this work was supported by the Femtosecond Spectroscopy Unit of the Okinawa Institute of Science and Technology Graduate University and JSPS Kakenhi Grant Number JP19K05637. We acknowledge the support for this work from the Imaging Section and Engineering Support Section of the Okinawa Institute of Science and Technology Graduate University. We acknowledge the Cambridge Royce facilities grant EP/P024947/1 and Sir Henry Royce Institute - recurrent grant EP/R00661X/1, and the Centre for Advanced Materials for Integrated Energy Systems (CAM-IES, EP/P007767/1). We thank Diamond Light Source for access and support in use of the electron Physical Science Imaging Centre (Instrument E02 and proposal number MG24111) and for providing beamtime at the I14 Hard X-ray Nanoprobe (proposal SP20420), which each contributed to the results presented here.

Author information

Author notes

  1. These authors contributed equally: Stuart Macpherson, Tiarnan A. S. Doherty

Authors and Affiliations

  1. Department of Physics, Cavendish Laboratory, University of Cambridge, Cambridge, UK

    Stuart Macpherson, Tiarnan A. S. Doherty, Yu-Hsien Chiang, Krzysztof Galkowski, Miguel Anaya, Kyle Frohna, Affan N. Iqbal, Zahra Andaji-Garmaroudi, Kieran W. P. Orr & Samuel D. Stranks

  2. Department of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge, UK

    Tiarnan A. S. Doherty, Miguel Anaya, Affan N. Iqbal, Satyawan Nagane, Bart Roose, Kieran W. P. Orr & Samuel D. Stranks

  3. Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Onna, Japan

    Andrew J. Winchester, Sofiia Kosar & Keshav M. Dani

  4. Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, UK

    Duncan N. Johnstone & Paul A. Midgley

  5. Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Toruń, Poland

    Krzysztof Galkowski

  6. Diamond Light Source, Harwell Science and Innovation Campus, Didcot, UK

    Julia E. Parker

Authors
  1. Stuart Macpherson
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Tiarnan A. S. Doherty
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Andrew J. Winchester
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Sofiia Kosar
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Duncan N. Johnstone
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Yu-Hsien Chiang
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Krzysztof Galkowski
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Miguel Anaya
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Kyle Frohna
    View author publications

    You can also search for this author in PubMed Google Scholar

  10. Affan N. Iqbal
    View author publications

    You can also search for this author in PubMed Google Scholar

  11. Satyawan Nagane
    View author publications

    You can also search for this author in PubMed Google Scholar

  12. Bart Roose
    View author publications

    You can also search for this author in PubMed Google Scholar

  13. Zahra Andaji-Garmaroudi
    View author publications

    You can also search for this author in PubMed Google Scholar

  14. Kieran W. P. Orr
    View author publications

    You can also search for this author in PubMed Google Scholar

  15. Julia E. Parker
    View author publications

    You can also search for this author in PubMed Google Scholar

  16. Paul A. Midgley
    View author publications

    You can also search for this author in PubMed Google Scholar

  17. Keshav M. Dani
    View author publications

    You can also search for this author in PubMed Google Scholar

  18. Samuel D. Stranks
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

S.M. prepared samples and collected, analysed and interpreted PEEM, steady-state PL, confocal TRPL and optical absorption data, and collected SED and nXRD data. T.A.S.D. prepared samples and collected, analysed and interpreted SED, high-angle annular dark-field, STEM-energy dispersive X-ray and nXRD data. A.J.W. collected, analysed and interpreted PEEM data. S.K. collected, analysed and interpreted PEEM and SEM data. D.N.J. collected, analysed and interpreted SED data. Y.-H.C. prepared devices, and collected device data and XRD data. K.G. collected and interpreted confocal TRPL data. M.A. and K.F. collected and interpreted nXRD data. A.N.I. collected and analysed SED data. S.N. prepared samples. B.R. collected SEM data. Z.A.-G. prepared samples. K.W.P.O. and J.E.P. collected nXRD data. P.A.M. supervised D.N.J. and assisted in the interpretation of SED data. K.M.D. supervised A.J.W. and S.K. S.D.S. supervised S.M., T.A.S.D., Y.-H.C., A.N.I., M.A., K.F., S.N., B.R. and Z.A.-G. S.D.S. conceived and designed the work. S.M., T.A.S.D. and S.D.S. produced first drafts and all authors contributed to editing the manuscript.

Corresponding authors

Correspondence to Keshav M. Dani or Samuel D. Stranks.

Ethics declarations

Competing interests

S.D.S. is a co-founder of Swift Solar, Inc.

Peer review

Peer review information

Nature thanks Alessandra Alberti, Ana Nogueira and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.

Additional information

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

Supplementary information

Supplementary Information

This file contains Supplementary Figs. 1–14, Supplementary Table 1, legend for Supplementary Video 1 and Supplementary References.

Peer Review File

41586_2022_4872_MOESM3_ESM.gif

Supplementary Video 1 SED data showing a pristine perovskite grain with an epitaxially aligned PbI2 inclusion at the grain boundary. Local diffraction patterns (right, scale bar, 0.75 Å−1) are extracted from the location of the red circle in the diffraction sum image (left, scale bar, 100 nm).

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Macpherson, S., Doherty, T.A.S., Winchester, A.J. et al. Local nanoscale phase impurities are degradation sites in halide perovskites. Nature 607, 294–300 (2022). https://doi.org/10.1038/s41586-022-04872-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41586-022-04872-1

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

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