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Cation and anion immobilization through chemical bonding enhancement with fluorides for stable halide perovskite solar cells

Abstract

Defects play an important role in the degradation processes of hybrid halide perovskite absorbers, impeding their application for solar cells. Among all defects, halide anion and organic cation vacancies are ubiquitous, promoting ion diffusion and leading to thin-film decomposition at surfaces and grain boundaries. Here, we employ fluoride to simultaneously passivate both anion and cation vacancies, by taking advantage of the extremely high electronegativity of fluoride. We obtain a power conversion efficiency of 21.46% (and a certified 21.3%-efficient cell) in a device based on the caesium, methylammonium (MA) and formamidinium (FA) triple-cation perovskite (Cs0.05FA0.54MA0.41)Pb(I0.98Br0.02)3 treated with sodium fluoride. The device retains 90% of its original power conversion efficiency after 1,000 h of operation at the maximum power point. With the help of first-principles density functional theory calculations, we argue that the fluoride ions suppress the formation of halide anion and organic cation vacancies, through a unique strengthening of the chemical bonds with the surrounding lead and organic cations.

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References

  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).

  2. 2.

    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 (2013).

  3. 3.

    Snaith, H. J. Perovskites: the emergence of a new era for low-cost, high-efficiency solar cells. J. Phys. Chem. Lett. 4, 3623–3630 (2013).

  4. 4.

    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).

  5. 5.

    Lee, M. M., Teuscher, 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).

  6. 6.

    Zhou, H. et al. Interface engineering of highly efficient perovskite solar cells. Science 345, 542–546 (2014).

  7. 7.

    Yang, W. S. et al. High-performance photovoltaic perovskite layers fabricated through intramolecular exchange. Science 348, 1234–1237 (2015).

  8. 8.

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

  9. 9.

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

  10. 10.

    Best Research-Cell Efficiencies (NREL, 2018); https://www.nrel.gov/pv/assets/pdfs/pv-efficiency-chart.20181221.pdf

  11. 11.

    Zheng, X. et al. Defect passivation in hybrid perovskite solar cells using quaternary ammonium halide anions and cations. Nat. Energy 2, 17102 (2017).

  12. 12.

    Ball, J. M. & Petrozza, A. Defects in perovskite-halides and their effects in solar cells. Nat. Energy 1, 16149 (2016).

  13. 13.

    Sherkar, T. S. et al. Recombination in perovskite solar cells: significance of grain boundaries, interface traps, and defect ions. ACS Energy Lett. 2, 1214–1222 (2017).

  14. 14.

    Kim, J., Lee, S.-H., Lee, J. H. & Hong, K.-H. The role of intrinsic defects in methylammonium lead iodide perovskite. J. Phys. Chem. Lett. 5, 1312–1317 (2014).

  15. 15.

    Duan, H.-S. et al. The identification and characterization of defect states in hybrid organic-inorganic perovskite photovoltaics. Phys. Chem. Chem. Phys. 17, 112–116 (2015).

  16. 16.

    Eames, C. et al. Ionic transport in hybrid lead iodide perovskite solar cells. Nat. Commun. 6, 7497 (2015).

  17. 17.

    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).

  18. 18.

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

  19. 19.

    Yin, W.-J., Shi, T. & Yan, Y. Unique properties of halide perovskites as possible origins of the superior solar cell performance. Adv. Mater. 26, 4653–4658 (2014).

  20. 20.

    Du, M. H. Efficient carrier transport in halide perovskites: theoretical perspectives. J. Mater. Chem. A 2, 9091–9098 (2014).

  21. 21.

    Yu, H., Lu, H., Xie, F., Zhou, S. & Zhao, N. Native defect-induced hysteresis behavior in organolead iodide perovskite solar cells. Adv. Funct. Mater. 26, 1411–1419 (2016).

  22. 22.

    Xiao, Z. et al. Giant switchable photovoltaic effect in organometal trihalide perovskite devices. Nat. Mater. 14, 193–198 (2015).

  23. 23.

    Wetzelaer, G.-J. A. H. et al. Trap-assisted non-radiative recombination in organic–inorganic perovskite solar cells. Adv. Mater. 27, 1837–1841 (2015).

  24. 24.

    Berhe, T. A. et al. Organometal halide perovskite solar cells: degradation and stability. Energy Environ. Sci. 9, 323–356 (2016).

  25. 25.

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

  26. 26.

    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).

  27. 27.

    Wang, S., Jiang, Y., Juarez-Perez, E. J., Ono, L. K. & Qi, Y. Accelerated degradation of methylammonium lead iodide perovskites induced by exposure to iodine vapour. Nat. Energy 2, 16195 (2016).

  28. 28.

    Juarez-Perez, E. J., Hawash, Z., Raga, S. R., Ono, L. K. & Qi, Y. Thermal degradation of CH3NH3PbI3 perovskite into NH3 and CH3I gases observed by coupled thermogravimetry–mass spectrometry analysis. Energy Environ. Sci. 9, 3406–3410 (2016).

  29. 29.

    Yang, M. et al. Facile fabrication of large-grain CH3NH3PbI3−xBrx films for high-efficiency solar cells via CH3NH3Br-selective Ostwald ripening. Nat. Commun. 7, 12305 (2016).

  30. 30.

    Wang, F. et al. Phenylalkylamine passivation of organolead halide perovskites enabling high-efficiency and air-stable photovoltaic cells. Adv. Mater. 28, 9986–9992 (2016).

  31. 31.

    Marco, N. D. et al. Guanidinium: a route to enhanced carrier lifetime and open-circuit voltage in hybrid perovskite solar cells. Nano Lett. 16, 1009–1016 (2016).

  32. 32.

    Noel, N. K. et al. Enhanced photoluminescence and solar cell performance via Lewis base passivation of organic–inorganic lead halide perovskites. ACS Nano 8, 9815–9821 (2014).

  33. 33.

    Abdi-Jalebi, M. et al. Maximizing and stabilizing luminescence from halide perovskites with potassium passivation. Nature 555, 497–501 (2018).

  34. 34.

    Son, D.-Y. et al. Universal approach toward hysteresis-free perovskite solar cell via defect engineering. J. Am. Chem. Soc. 140, 1358–1364 (2018).

  35. 35.

    Cao, J., Tao, S. X., Bobbert, P. A., Wong, C.-P. & Zhao, N. Interstitial occupancy by extrinsic alkali cations in perovskites and its impact on ion migration. Adv. Mater. 30, 1707350 (2018).

  36. 36.

    Yang, D., Yang, Y. & Liu, Y. A theoretical study on the red- and blue-shift hydrogen bonds of cis- trans formic acid dimer in excited states. Cent. Eur. J. Chem 11, 171–179 (2013).

  37. 37.

    Philippe, B. et al. Chemical and electronic structure characterization of lead halide perovskites and stability behavior under different exposures—a photoelectron spectroscopy investigation. Chem. Mater. 27, 1720–1731 (2015).

  38. 38.

    Chen, Q. et al. Controllable self-induced passivation of hybrid lead iodide perovskites toward high performance solar cells. Nano Lett. 14, 4158–4163 (2014).

  39. 39.

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

  40. 40.

    Abdi-Jalebi, M. et al. Impact of monovalent cation halide additives on the structural and optoelectronic properties of CH3NH3PbI3 perovskite. Adv. Energy Mater. 6, 1502472 (2016).

  41. 41.

    Snaith, H. J. et al. Anomalous hysteresis in perovskite solar cells. J. Phys. Chem. Lett. 5, 1511–1515 (2014).

  42. 42.

    Wang, L. et al. A-site cation effect on growth thermodynamics and photoconductive properties in ultrapure lead iodine perovskite monocrystalline wires. ACS Appl. Mater. Interfaces 9, 25985–25994 (2017).

  43. 43.

    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).

  44. 44.

    Kresse, G. & Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 54, 11169–11186 (1996).

  45. 45.

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

  46. 46.

    Blöchl, P. E. Projector augmented-wave method. Phys. Rev. B 50, 17953–17979 (1994).

  47. 47.

    Kresse, G. & Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 59, 1758–1775 (1999).

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Acknowledgements

This work is supported by the National Natural Science Foundation of China (51722201; 51672008; 91733301), National Key Research and Development Program of China grant no. 2017YFA0206701, the Natural Science Foundation of Beijing, China (grant no. 4182026), the Young Talent Thousand Program, National Key Research and Development Program of China grant no. 2016YFB0700700, the National Natural Science Foundation of China (51673025) and Beijing Municipal Science and Technology Project no. Z181100005118002. S.T. acknowledges funding from the Computational Sciences for Energy Research tenure track programme of Shell, NWO and FOM (project no. 15CST04-2). The authors would like to thank W. Zou and J. Wang (Nanjing Tech University) for the PLQE measurement during the revision process, and Z. Dai for providing the dynamic light scattering measurement.

Author information

H.Z. and N.L. conceived the idea and designed the experiments. S.T. designed and performed the DFT calculations. Both N.L. and X.N. were involved in all of the experimental parts. Y.C., Z.X., L.W. and H.L. contributed to the fabrication of high-performance PSCs. Z.Q., Y.Z. and L.L. helped to modify the experiments. Y.Lun, X.W. and J.H. performed the KPFM measurements, while Y.Liu, H.X. and Y.G. carried out the UPS and XPS measurement. G.Z. provided the film microstructure analysis. G.B. and C.K.O. assisted in DFT calculations. C.H., Y.B. and S.Y. performed ToF-SIMS measurements. H.Z., Q.C., S.T. and N.L. wrote the manuscript. C.K.O., X.N. and G.B. revised the manuscript. All authors were involved in the discussion of data analysis and commented on the manuscript. N.L. and S.T. have contributed equally to this work.

Competing interests

The authors declare no competing interests.

Correspondence to Huanping Zhou.

Supplementary information

  1. Supplementary Information

    Supplementary Notes 1–14, Figs. 1–21, Tables 1–3 and references.

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DOI

https://doi.org/10.1038/s41560-019-0382-6

Fig. 1: The characterization of perovskite thin films (CsFAMA and CsFAMA-X).
Fig. 2: Surface and bulk characterization of perovskite films.
Fig. 3: Location of Na and F ions and effects on chemical bonding strength and formation energy of FA vacancies.
Fig. 4: Performance of PSCs.
Fig. 5: Stability performance of PSCs under various conditions.