Suppression of atomic vacancies via incorporation of isovalent small ions to increase the stability of halide perovskite solar cells in ambient air


The degradation of perovskite solar cells in the presence of trace water and oxygen poses a challenge for their commercial impact given the appreciable permeability of cost-effective encapsulants. Point defects were recently shown to be a major source of decomposition due to their high affinity for water and oxygen molecules. Here, we report that, in single-cation/halide perovskites, local lattice strain facilitates the formation of vacancies and that cation/halide mixing suppresses their formation via strain relaxation. We then show that judiciously selected dopants can maximize the formation energy of defects responsible for degradation. Cd-containing cells show an order of magnitude enhanced unencapsulated stability compared to state-of-art mixed perovskite solar cells, for both shelf storage and maximum power point operation in ambient air at a relative humidity of 50%. We conclude by testing the generalizability of the defect engineering concept, demonstrating both vacancy-formation suppressors (such as Zn) and promoters (such as Hg).

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Fig. 1: Characterization of CsMAFA single crystals.
Fig. 2: Formation energies of antisites and Schottky vacancies.
Fig. 3: Mechanisms of lattice relaxation.
Fig. 4: Characterization of CsMAFA perovskite films with and without dopants.
Fig. 5: Performance of CsMAFA PSCs with and without dopants.


  1. 1.

    Kojima, A., Teshima, K., Shirai, Y. & Miyasaka, T. Organometal halide perovskites as visible-light sensitizers for photovoltaic cells. J. Am. Chem. Soc. 131, 6050–6051 (2009).

    Article  Google Scholar 

  2. 2.

    Im, J.-H., Lee, C.-R., Lee, J.-W., Park, S.-W. & Park, N.-G. 6.5% efficient perovskite quantum-dot-sensitized solar cell. Nanoscale 3, 4088 (2011).

    Article  Google Scholar 

  3. 3.

    Kim, H.-S. et al. Lead iodide perovskite sensitized all-solid-state submicron thin film mesoscopic solar cell with efficiency exceeding 9%. Sci. Rep. 2, 591 (2012).

    Article  Google Scholar 

  4. 4.

    Burschka, J. et al. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499, 316–320 (2013).

    Article  Google Scholar 

  5. 5.

    Hao, F., Stoumpos, C. C., Liu, Z., Chang, R. P. H. & Kanatzidis, M. G. Controllable perovskite crystallization at a gas–solid interface for hole conductor-free solar cells with steady power conversion efficiency over 10%. J. Am. Chem. Soc. 136, 16411–16419 (2014).

    Article  Google Scholar 

  6. 6.

    Im, J.-H., Jang, I.-H., Pellet, N., Grätzel, M. & Park, N.-G. Growth of CH3NH3PbI3 cuboids with controlled size for high-efficiency perovskite solar cells. Nat. Nanotech. 9, 927–932 (2014).

    Article  Google Scholar 

  7. 7.

    Stranks, S. D. & Snaith, H. J. Metal-halide perovskites for photovoltaic and light-emitting devices. Nat. Nanotech. 10, 391–402 (2015).

    Article  Google Scholar 

  8. 8.

    Yang, Y. & You, J. Make perovskite solar cells stable. Nature 544, 155–156 (2017).

    Article  Google Scholar 

  9. 9.

    Christians, J. A. et al. Tailored interfaces of unencapsulated perovskite solar cells for > 1,000 hour operational stability. Nat. Energy 3, 68–74 (2018).

    Article  Google Scholar 

  10. 10.

    Hou, Y. et al. A generic interface to reduce the efficiency-stability-cost gap of perovskite solar cells. Science 358, 1192–1197 (2017).

    Article  Google Scholar 

  11. 11.

    Zhao, P., Kim, B. J. & Jung, H. S. Passivation in perovskite solar cells: A review. Mater. Today Energy 7, 267–286 (2018).

    Article  Google Scholar 

  12. 12.

    Arora, N. et al. Perovskite solar cells with CuSCN hole extraction layers yield stabilized efficiencies greater than 20%. Science 358, 768–771 (2017).

    Article  Google Scholar 

  13. 13.

    You, J. et al. Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers. Nat. Nanotech. 11, 75–81 (2015).

    Article  Google Scholar 

  14. 14.

    Wang, Z. et al. Efficient ambient-air-stable solar cells with 2D–3D heterostructured butylammonium-caesium-formamidinium lead halide perovskites. Nat. Energy 2, 17135 (2017).

    Article  Google Scholar 

  15. 15.

    Tsai, H. et al. High-efficiency two-dimensional Ruddlesden–Popper perovskite solar cells. Nature 536, 312–316 (2016).

    Article  Google Scholar 

  16. 16.

    Eperon, G. E. et al. Formamidinium lead trihalide: a broadly tunable perovskite for efficient planar heterojunction solar cells. Energy Environ. Sci. 7, 982 (2014).

    Article  Google Scholar 

  17. 17.

    Lee, J.-W. et al. Formamidinium and cesium hybridization for photo- and moisture-stable perovskite solar cell. Adv. Energy Mater. 5, 1501310 (2015).

    Article  Google Scholar 

  18. 18.

    Li, Z. et al. Stabilizing perovskite structures by tuning tolerance factor: formation of formamidinium and cesium lead iodide solid-state alloys. Chem. Mater. 28, 284–292 (2016).

    Article  Google Scholar 

  19. 19.

    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 

  20. 20.

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

    Article  Google Scholar 

  21. 21.

    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 

  22. 22.

    Bush, K. A. et al. 23.6%-efficient monolithic perovskite/silicon tandem solar cells with improved stability. Nat. Energy 2, 17009 (2017).

    Article  Google Scholar 

  23. 23.

    Amat, A. et al. Cation-induced band-gap tuning in organohalide perovskites: interplay of spin–orbit coupling and octahedra tilting. Nano Lett. 14, 3608–3616 (2014).

    Article  Google Scholar 

  24. 24.

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

    Article  Google Scholar 

  25. 25.

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

    Article  Google Scholar 

  26. 26.

    Xie, L. et al. Understanding the cubic phase stabilization and crystallization kinetics in mixed cations and halides perovskite single crystals. J. Am. Chem. Soc. 139, 3320–3323 (2017).

    Article  Google Scholar 

  27. 27.

    Zheng, X. et al. Improved phase stability of formamidinium lead triiodide perovskite by strain relaxation. ACS Energy Lett. 1, 1014–1020 (2016).

    Article  Google Scholar 

  28. 28.

    Syzgantseva, O. A., Saliba, M., Gratzel, M. & Rothlisberger, U. Stabilization of the perovskite phase of formamidinium lead triiodide by methylammonium, Cs, and/or Rb doping. J. Phys. Chem. Lett. 8, 1191–1196 (2017).

    Article  Google Scholar 

  29. 29.

    Yi, C. et al. Entropic stabilization of mixed A-cation ABX3 metal halide perovskites for high performance perovskite solar cells. Energy Environ. Sci. 9, 656–662 (2016).

    Article  Google Scholar 

  30. 30.

    Jong, U.-G., Yu, C.-J., Ri, J.-S., Kim, N.-H. & Ri, G.-C. Influence of halide composition on the structural, electronic, and optical properties of mixed CH3NH3Pb(I1−xBrx)3 perovskites calculated using the virtual crystal approximation method. Phys. Rev. B 94, 125139 (2016).

    Article  Google Scholar 

  31. 31.

    Jong, U.-G. et al. Revealing the stability and efficiency enhancement in mixed halide perovskites MAPb(I1–xClx)3 with ab initio calculations. J. Power Sources 350, 65–72 (2017).

    Article  Google Scholar 

  32. 32.

    Han, Y. et al. Degradation observations of encapsulated planar CH3NH3PbI3 perovskite solar cells at high temperatures and humidity. J. Mater. Chem. A 3, 8139–8147 (2015).

    Article  Google Scholar 

  33. 33.

    Leijtens, T. et al. Towards enabling stable lead halide perovskite solar cells; interplay between structural, environmental, and thermal stability. J. Mater. Chem. A 5, 11483–11500 (2017).

    Article  Google Scholar 

  34. 34.

    Buin, A. et al. Materials processing routes to trap-free halide perovskites. Nano Lett. 14, 6281–6286 (2014).

    Article  Google Scholar 

  35. 35.

    Aschauer, U., Pfenninger, R., Selbach, S. M., Grande, T. & Spaldin, N. A. Strain-controlled oxygen vacancy formation and ordering in CaMnO3. Phys. Rev. B 88, 54111 (2013).

    Article  Google Scholar 

  36. 36.

    Liu, Y. et al. Atomistic origins of surface defects in CH3NH3PbBr3 perovskite and their electronic structures. ACS Nano 11, 2060–2065 (2017).

    Article  Google Scholar 

  37. 37.

    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 

  38. 38.

    Aristidou, N. et al. The role of oxygen in the degradation of methylammonium lead trihalide perovskite photoactive layers. Angew. Chem. Int. Ed. 54, 8208–8212 (2015).

    Article  Google Scholar 

  39. 39.

    Lu, Y. et al. Effective calcium doping at the B-site of BaFeO3−δ perovskite: towards low-cost and high-performance oxygen permeation membranes. J. Mater. Chem. A 5, 7999–8009 (2017).

    Article  Google Scholar 

  40. 40.

    Stranks, S. D. et al. Electron–hole diffusion lengths exceeding 1 micrometer in an organometal trihalide perovskite absorber. Science 342, 341–344 (2013).

    Article  Google Scholar 

  41. 41.

    Lee, M. M., Teuscher, J. J., Miyasaka, T., Murakami, T. N. & Snaith, H. J. Efficient hybrid solar cells based on meso-superstructured organometal halide perovskites. Science 338, 643–647 (2012).

    Article  Google Scholar 

  42. 42.

    Dar, M. I. et al. Investigation regarding the role of chloride in organic–inorganic halide perovskites obtained from chloride containing precursors. Nano Lett. 14, 6991–6996 (2014).

    Article  Google Scholar 

  43. 43.

    Colella, S. et al. Elusive presence of chloride in mixed halide perovskite solar cells. J. Phys. Chem. Lett. 5, 3532–3538 (2014).

    Article  Google Scholar 

  44. 44.

    Chen, Q. et al. The optoelectronic role of chlorine in CH3NH3PbI3(Cl)-based perovskite solar cells. Nat. Commun. 6, 7269 (2015).

    Article  Google Scholar 

  45. 45.

    Starr, D. E. et al. Direct observation of an inhomogeneous chlorine distribution in CH3NH3PbI3-xClx layers: surface depletion and interface enrichment. Energy Environ. Sci. 8, 1609–1615 (2015).

    Article  Google Scholar 

  46. 46.

    Yin, W.-J., Chen, H., Shi, T., Wei, S.-H. & Yan, Y. Origin of high electronic quality in structurally disordered CH3NH3PbI3 and the passivation effect of Cl and O at grain boundaries. Adv. Electron. Mater. 1, 1500044 (2015).

    Article  Google Scholar 

  47. 47.

    Fan, L. et al. Elucidating the role of chlorine in perovskite solar cells. J. Mater. Chem. A 5, 7423–7432 (2017).

    Article  Google Scholar 

  48. 48.

    Liao, H.-C. et al. Enhanced efficiency of hot-cast large-area planar perovskite solar cells/modules having controlled chloride incorporation. Adv. Energy Mater. 7, 1601660 (2017).

    Article  Google Scholar 

  49. 49.

    Wu, X. et al. Trap states in lead iodide perovskites. J. Am. Chem. Soc. 137, 2089–2096 (2015).

    Article  Google Scholar 

  50. 50.

    Jung, Y.-K., Lee, J.-H., Walsh, A. & Soon, A. Influence of Rb/Cs cation-exchange on inorganic Sn halide perovskites: from chemical structure to physical properties. Chem. Mater. 29, 3181–3188 (2017).

    Article  Google Scholar 

  51. 51.

    Walsh, A., Scanlon, D. O., Chen, S., Gong, X. G. & Wei, S.-H. Self-regulation mechanism for charged point defects in hybrid halide perovskites. Angew. Chem. Int. Ed 54, 1791–1794 (2015).

    Article  Google Scholar 

  52. 52.

    Noh, J. H., Im, S. H., Heo, J. H., Mandal, T. N. & Seok, S.II Chemical management for colorful, efficient, and stable inorganic-organic hybrid nanostructured solar cells. Nano Lett. 13, 1764–1769 (2013).

    Article  Google Scholar 

  53. 53.

    Dastidar, S. et al. High chloride doping levels stabilize the perovskite phase of cesium lead iodide. Nano Lett. 16, 3563–3570 (2016).

    Article  Google Scholar 

  54. 54.

    Dunlap-Shohl, W. A., Younts, R., Gautam, B., Gundogdu, K. & Mitzi, D. B. Effects of Cd diffusion and doping in high-performance perovskite solar cells using CdS as electron transport layer. J. Phys. Chem. C 120, 16437–16445 (2016).

    Article  Google Scholar 

  55. 55.

    Kubicki, D. J. et al. Phase segregation in Cs-, Rb- and K-doped mixed-cation (MA)x(FA)1– xPbI3 hybrid perovskites from solid-state NMR. J. Am. Chem. Soc. 139, 14173–14180 (2017).

    Article  Google Scholar 

  56. 56.

    Domanski, K., Alharbi, E. A., Hagfeldt, A., Grätzel, M. & Tress, W. Systematic investigation of the impact of operation conditions on the degradation behaviour of perovskite solar cells. Nat. Energy 3, 61–67 (2018).

    Article  Google Scholar 

  57. 57.

    Barker, A. J. et al. Defect-assisted photoinduced halide segregation in mixed-halide perovskite thin films. ACS Energy Lett. 2, 1416–1424 (2017).

    Article  Google Scholar 

  58. 58.

    Saidaminov, M. I. et al. High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization. Nat. Commun. 6, 7586 (2015).

    Article  Google Scholar 

  59. 59.

    Kadro, J. M., Nonomura, K., Gachet, D., Grätzel, M. & Hagfeldt, A. Facile route to freestanding CH3NH3PbI3 crystals using inverse solubility. Sci. Rep. 5, 11654 (2015).

    Article  Google Scholar 

  60. 60.

    Liu, Y. et al. Two-inch-sized perovskite CH3NH3PbX3 (X = Cl, Br, I) crystals: growth and characterization. Adv. Mater. 27, 5176–5183 (2015).

    Article  Google Scholar 

  61. 61.

    Zhang, T. et al. A facile solvothermal growth of single crystal mixed halide perovskite CH3NH3Pb(Br1−xClx)3. Chem. Commun. 51, 7820–7823 (2015).

    Article  Google Scholar 

  62. 62.

    Nazarenko, O., Yakunin, S., Morad, V., Cherniukh, I. & Kovalenko, M. V. Single crystals of caesium formamidinium lead halide perovskites: solution growth and gamma dosimetry. NPG Asia Mater. 9, e373 (2017).

    Article  Google Scholar 

  63. 63.

    Park, N.-G., Grätzel, M., Miyasaka, T., Zhu, K. & Emery, K. Towards stable and commercially available perovskite solar cells. Nat. Energy 1, 16152 (2016).

    Article  Google Scholar 

  64. 64.

    Quan, L. N. et al. Ligand-stabilized reduced-dimensionality perovskites. J. Am. Chem. Soc. 138, 2649–2655 (2016).

    Article  Google Scholar 

  65. 65.

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

    Article  Google Scholar 

  66. 66.

    VandeVondele, J. & Hutter, J. Gaussian basis sets for accurate calculations on molecular systems in gas and condensed phases. J. Chem. Phys. 127, 114105 (2007).

    Article  Google Scholar 

  67. 67.

    Press, W. H. Numerical Recipes: The Art of Scientific Computing (Cambridge Univ. Press, Cambridge, 2007).

Download references


This publication is partly based on work supported by an award (KUS-11-009-21) from the King Abdullah University of Science and Technology, by the Ontario Research Fund and by the Natural Sciences and Engineering Research Council of Canada. M.I.S. acknowledges the support of the Banting Postdoctoral Fellowship Program, administered by the Government of Canada. The work of A. Jain is supported by the IBM Canada Research and Development Center through the Southern Ontario Smart Computing Innovation Platform (SOSCIP) postdoctoral fellowship. DFT calculations were performed on the IBM BlueGene Q supercomputer with support from the SOSCIP. H.T. acknowledges the Netherlands Organization for Scientific Research (NWO) for a Rubicon grant (680-50-1511) in support of his postdoctoral research at the University of Toronto. We thank R. Wolowiec, D. Kopilovic, L. Levina and E. Palmiano for their help during the course of the study.

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M.I.S. and J.K. conceived the idea, grew crystals, fabricated all devices and characterized them. A. Jain and O.V. performed DFT calculations. A. Johnston assisted in PL measurements. H.T. and F.T. assisted in solar cell fabrication and testing. R.Q.B. performed XPS. G.L., Y.Z. and H.T. assisted with the experiments and discussions. O.V. and E.H.S directed the overall research. M.I.S., J.K., O.V. and E.H.S. wrote the manuscript. All authors read and commented on the manuscript.

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Correspondence to Edward H. Sargent.

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Supplementary Tables 1–6, Supplementary Figures 1–19, Supplementary References

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Supplementary Data 1

Representative VASP input files for the DFT simulations

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Saidaminov, M.I., Kim, J., Jain, A. 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).

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