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Enhanced stability and efficiency in hole-transport-layer-free CsSnI3 perovskite photovoltaics

Abstract

Photovoltaics based on tin halide perovskites have not yet benefited from the same intensive research effort that has propelled lead perovskite photovoltaics to >20% power conversion efficiency, due to the susceptibility of tin perovskites to oxidation, the low energy of defect formation and the difficultly in forming pinhole-free films. Here we report CsSnI3 perovskite photovoltaic devices without a hole-selective interfacial layer that exhibit a stability 10 times greater than devices with the same architecture using methylammonium lead iodide perovskite, and the highest efficiency to date for a CsSnI3 photovoltaic: 3.56%. The latter largely results from a high device fill factor, achieved using a strategy that removes the need for an electron-blocking layer or an additional processing step to minimize the pinhole density in the perovskite film, based on co-depositing the perovskite precursors with SnCl2. These two findings raise the prospect that this class of lead-free perovskite photovoltaic may yet prove viable for applications.

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Figure 1: Evolution of the absorption spectrum of CsSnI3 films with different tin halide additives in ambient air.
Figure 2: SEM images of CsSnI3 films on ITO glass prepared with different tin halide additives.
Figure 3: Evolution of XRD patterns of CsSnI3 films with and without SnCl2 additive under different conditions.
Figure 4: HRXPS Cl 2p spectra of films of SnCl2 and CsSnI3 + 10 mol% SnCl2 before and after exposure to ambient air.
Figure 5: Current–voltage (JV) characteristics of CsSnI3 PPVs before and after a period of extended storage under nitrogen.
Figure 6: Band diagrams depicting the energy level alignment at the ITO/PC61BM interface and spectroscopic evidence for an n-type doping interaction.
Figure 7: PPV device stability tests under 1 sun constant illumination in ambient air for unencapsulated devices with the same architecture.

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).

    Article  Google Scholar 

  2. 2

    Xu, T., Chen, L., Guo, Z. & Ma, T. Strategic improvement of the long-term stability of perovskite materials and perovskite solar cells. Phys. Chem. Chem. Phys. 18, 27026–27050 (2016).

    Article  Google Scholar 

  3. 3

    Pyykkö, P. Relativistic effects in structural chemistry. Chem. Rev. 88, 563–594 (1988).

    Article  Google Scholar 

  4. 4

    Boix, P. P., Agarwala, S., Koh, T. M., Mathews, N. & Mhaisalkar, S. G. Perovskite solar cells: beyond methylammonium lead iodide. J. Phys. Chem. Lett. 6, 898–907 (2015).

    Article  Google Scholar 

  5. 5

    Noel, N. K. et al. Lead-free organic-inorganic tin halide perovskites for photovoltaic applications. Energy Environ. Sci. 7, 3061–3068 (2014).

    Article  Google Scholar 

  6. 6

    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).

    Article  Google Scholar 

  7. 7

    Xu, P., Chen, S., Xiang, H.-J., Gong, X.-G. & Wei, S.-H. Influence of defects and synthesis conditions on the photovoltaic performance of perovskite semiconductor CsSnI3 . Chem. Mater. 26, 6068–6072 (2014).

    Article  Google Scholar 

  8. 8

    Kumar, M. H. et al. Lead-free halide perovskite solar cells with high photocurrents realized through vacancy modulation. Adv. Mater. 26, 7122–7127 (2014).

    Article  Google Scholar 

  9. 9

    Yokoyama, T. et al. Overcoming short-circuit in lead-free CH3NH3SnI3 perovskite solar cells via kinetically controlled gas–solid reaction film fabrication process. J. Phys. Chem. Lett. 7, 776–782 (2016).

    Article  Google Scholar 

  10. 10

    Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p–n junction solar cells. J. Appl. Phys. 32, 510–519 (1961).

    Article  Google Scholar 

  11. 11

    Chung, I. et al. CsSnI3: semiconductor or metal? High electrical conductivity and strong near-infrared photoluminescence from a single material. High hole mobility and phase-transitions. J. Am. Chem. Soc. 134, 8579–8587 (2012).

    Article  Google Scholar 

  12. 12

    Huang, L. & Lambrecht, W. R. L. Electronic band structure, phonons, and exciton binding energies of halide perovskites CsSnCl3, CsSnBr3, and CsSnI3 . Phys. Rev. B 88, 165203 (2013).

    Article  Google Scholar 

  13. 13

    Chen, Z. et al. Photoluminescence study of polycrystalline CsSnI3 thin films: determination of exciton binding energy. J. Lumin. 132, 345–349 (2012).

    Article  Google Scholar 

  14. 14

    Zhang, J. et al. Energy barrier at the N719-dye/CsSnI3 interface for photogenerated holes in dye-sensitized solar cells. Sci. Rep. 4, 6954 (2014).

    Article  Google Scholar 

  15. 15

    Stoumpos, C. C., Malliakas, C. D. & Kanatzidis, M. G. Semiconducting tin and lead iodide perovskites with organic cations: phase transitions, high mobilities, and near-infrared photoluminescent properties. Inorg. Chem. 52, 9019–9038 (2013).

    Article  Google Scholar 

  16. 16

    Hao, F. et al. Solvent-mediated crystallization of CH3NH3SnI3 films for heterojunction depleted perovskite solar cells. J. Am. Chem. Soc. 137, 11445–11452 (2015).

    Article  Google Scholar 

  17. 17

    Sabba, D. et al. Impact of anionic Br- substitution on open circuit voltage in lead free perovskite (CsSnI3−xBrx) solar cells. J. Phys. Chem. C 119, 1763–1767 (2015).

    Article  Google Scholar 

  18. 18

    Chen, Z., Wang, J. J., Ren, Y., Yu, C. & Shum, K. Schottky solar cells based on CsSnI3 thin-films. Appl. Phys. Lett. 101, 93901 (2012).

    Article  Google Scholar 

  19. 19

    Marshall, K. P., Walton, R. I. & Hatton, R. A. Tin perovskite/fullerene planar layer photovoltaics: improving the efficiency and stability of lead-free devices. J. Mater. Chem. A 3, 11631–11640 (2015).

    Article  Google Scholar 

  20. 20

    Koh, T. M. Formamidinium tin-based perovskite with low Eg for photovoltaic applications. J. Mater. Chem. A 3, 14996–15000 (2015).

    Article  Google Scholar 

  21. 21

    Zhang, M. et al. Low-temperature processed solar cells with formamidinium tin halide perovskite/fullerene heterojunctions. Nano Res. 9, 1570–1577 (2016).

    Article  Google Scholar 

  22. 22

    Werker, W. Die Kristallstruktur des Rb2SnI6 und Cs2SnI6 . Recl. Trav. Chim. Pay. 58, 257–258 (1939).

    Article  Google Scholar 

  23. 23

    Lee, B. et al. Air-stable molecular semiconducting iodosalts for solar cell applications: Cs2SnI6 as a hole conductor. J. Am. Chem. Soc. 136, 15379–15385 (2014).

    Article  Google Scholar 

  24. 24

    Xiao, Z., Zhou, Y., Hosono, H. & Kamiya, T. Intrinsic defects in a photovoltaic perovskite variant Cs2SnI6 . Phys. Chem. Chem. Phys. 17, 18900–18903 (2015).

    Article  Google Scholar 

  25. 25

    Peedikakkandy, L. & Bhargava, P. Composition dependent optical, structural and photoluminescence characteristics of cesium tin halide perovskites. RSC Adv. 6, 19857–19860 (2016).

    Article  Google Scholar 

  26. 26

    Shannon, R. D. Revised Effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr. A A32, 751–767 (1976).

    Article  Google Scholar 

  27. 27

    Moses, P. R. et al. X-ray photoelectron spectroscopy of alkylamine-silanes. Anal. Chem. 50, 576–585 (1978).

    Article  Google Scholar 

  28. 28

    Alonzo, G. et al. Mössbauer, far-infrared, and XPS investigations of SnCl2 and SnCl4 introduced in polyconjugated monosubstituted acetylene matrices. Appl. Spectrosc. 49, 237–240 (1995).

    Article  Google Scholar 

  29. 29

    Zhang, Y. et al. Flexible, hole transporting layer-free and stable CH3NH3PbI3/ PC61BM planar heterojunction perovskite solar cells. Org. Electron. 30, 281–288 (2016).

    Article  Google Scholar 

  30. 30

    Chung, I., Lee, B., He, J., Chang, R. P. H. & Kanatzidis, M. G. All-solid-state dye-sensitized solar cells with high efficiency. Nature 485, 486–489 (2012).

    Article  Google Scholar 

  31. 31

    Tyler, M. S., Nadeem, I. M. & Hatton, R. A. An electrode design rule for high performance top-illuminated organic photovoltaics. Mater. Horiz. 3, 348–354 (2016).

    Article  Google Scholar 

  32. 32

    Yan, Y. Perovskite solar cells: high voltage from ordered fullerenes. Nat. Energy 1, 15007 (2016).

    Article  Google Scholar 

  33. 33

    Shao, Y., Yuan, Y. & Huang, J. Correlation of energy disorder and open-circuit voltage in hybrid perovskite solar cells. Nat. Energy 1, 15001 (2016).

    Article  Google Scholar 

  34. 34

    Saparov, B. et al. Thin-film deposition and characterization of a Sn-deficient perovskite derivative Cs2SnI6 . Chem. Mater. 28, 2315–2322 (2016).

    Article  Google Scholar 

  35. 35

    Glen, T. S. et al. Dependence on material choice of degradation of organic solar cells following exposure to humid air. J. Polym. Sci. B 54, 216–224 (2016).

    Article  Google Scholar 

Download references

Acknowledgements

The authors would like to thank the United Kingdom Engineering and Physical Sciences Research Council (EPSRC) for funding (Grant numbers: EP/L505110/1 & EP/N009096/1). All data supporting this study are provided as Supplementary Information accompanying this paper.

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K.P.M. performed all of the experimental work. K.P.M., R.I.W. and R.A.H. conceived the experiments, analysed the results and wrote the paper. M.W. collected the XPS and UPS data and helped to analyse the results.

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Correspondence to R. A. Hatton.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Figures 1–14, Supplementary Tables 1–6, Supplementary Discussion. (PDF 1927 kb)

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Marshall, K., Walker, M., Walton, R. et al. Enhanced stability and efficiency in hole-transport-layer-free CsSnI3 perovskite photovoltaics. Nat Energy 1, 16178 (2016). https://doi.org/10.1038/nenergy.2016.178

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