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.

Molecularly thin two-dimensional hybrid perovskites with tunable optoelectronic properties due to reversible surface relaxation

Abstract

Due to their layered structure, two-dimensional Ruddlesden–Popper perovskites (RPPs), composed of multiple organic/inorganic quantum wells, can in principle be exfoliated down to few and single layers. These molecularly thin layers are expected to present unique properties with respect to the bulk counterpart, due to increased lattice deformations caused by interface strain. Here, we have synthesized centimetre-sized, pure-phase single-crystal RPP perovskites (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 (n = 1–4) from which single quantum well layers have been exfoliated. We observed a reversible shift in excitonic energies induced by laser annealing on exfoliated layers encapsulated by hexagonal boron nitride. Moreover, a highly efficient photodetector was fabricated using a molecularly thin n = 4 RPP crystal, showing a photogain of 105 and an internal quantum efficiency of ~34%. Our results suggest that, thanks to their dynamic structure, atomically thin perovskites enable an additional degree of control for the bandgap engineering of these materials

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Fig. 1: Large-sized monolayers (n = 1, 2, 3, 4 series) mechanically exfoliated from bulk (CH3(CH2)3NH3)2(CH3NH3)n−1PbnI3n+1 single crystals.
Fig. 2: Optical characterization of bulk and monolayer (single unit cell) RPP flakes.
Fig. 3: Reversible exciton states in RPP monolayers.
Fig. 4: Q-plus nc-AFM images on in situ exfoliated n = 4 RPP flake surface.
Fig. 5: (C4H9NH3)2(CH3NH3)3Pb4I13 n = 4 perovskite photodetector device fabricated on exfoliated flakes of different thickness, with excitation by a 532 nm focused laser of spot size 1 μm2.

Data availability

The data supporting the findings of this study are available within the Article and its Supplementary Information or from the authors.

References

  1. 1.

    Novoselov, K., Mishchenko, A., Carvalho, A. & Neto, A. C. 2D materials and van der Waals heterostructures. Science 353, aac9439 (2016).

    CAS  Article  Google Scholar 

  2. 2.

    Stoumpos, C. C. et al. Ruddlesden–Popper hybrid lead iodide perovskite 2D homologous semiconductors. Chem. Mater. 28, 2852–2867 (2016).

    CAS  Article  Google Scholar 

  3. 3.

    Mitzi, D. B., Feild, C. A., Harrison, W. T. A. & Guloy, A. M. Conducting tin halides with a layered organic-based perovskite structure. Nature 369, 467–469 (1994).

    CAS  Article  Google Scholar 

  4. 4.

    Ishihara, T., Takahashi, J. & Goto, T. Optical properties due to electronic transitions in two-dimensional semiconductors (CnH2n+1NH3)PbI4. Phys. Rev. B 42, 11099–11107 (1990).

    CAS  Article  Google Scholar 

  5. 5.

    Tanaka, K. et al. Electronic and excitonic structures of inorganic-organic perovskite-type quantum-well crystal (C4H9NH3)2PbBr4. Jpn J. Appl. Phys. 44, 5923–5932 (2005).

    CAS  Article  Google Scholar 

  6. 6.

    Saparov, B. & Mitzi, D. B. Organic–inorganic perovskites: structural versatility for functional materials design. Chem. Rev. 116, 4558–4596 (2016).

    CAS  Article  Google Scholar 

  7. 7.

    Shi, E. et al. Two-dimensional halide perovskite nanomaterials and heterostructures. Chem. Soc. Rev. 47, 6046–6072 (2018).

    CAS  Article  Google Scholar 

  8. 8.

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

    CAS  Article  Google Scholar 

  9. 9.

    Blancon, J.-C. et al. Extremely efficient internal exciton dissociation through edge states in layered 2D perovskites. Science 355, 1288–1292 (2017).

    CAS  Article  Google Scholar 

  10. 10.

    Quan, L. N. et al. Tailoring the energy landscape in quasi-2D halide perovskites enables efficient green-light emission. Nano Lett. 17, 3701–3709 (2017).

    CAS  Article  Google Scholar 

  11. 11.

    Yuan, M. J. et al. Perovskite energy funnels for efficient light-emitting diodes. Nat. Nanotech. 11, 872–877 (2016).

    CAS  Article  Google Scholar 

  12. 12.

    Dou, L. et al. Atomically thin two-dimensional organic–inorganic hybrid perovskites. Science 349, 1518–1521 (2015).

    CAS  Article  Google Scholar 

  13. 13.

    Niu, W., Eiden, A., Prakash, G. V. & Baumberg, J. Exfoliation of self-assembled 2D organic–inorganic perovskite semiconductors. Appl. Phys. Lett. 104, 171111 (2014).

    Article  Google Scholar 

  14. 14.

    Yaffe, O. et al. Excitons in ultrathin organic–inorganic perovskite crystals. Phys. Rev. B 92, 045414 (2015).

    Article  Google Scholar 

  15. 15.

    Mitzi, D. B. in Progress in Inorganic Chemistry Vol. 48 (ed. Karlin, K.) 1–121 (Wiley, New York, NY, 1999).

  16. 16.

    Jaffe, A. et al. High-pressure single-crystal structures of 3D lead-halide hybrid perovskites and pressure effects on their electronic and optical properties. ACS Cent. Sci. 2, 201–209 (2016).

    CAS  Article  Google Scholar 

  17. 17.

    Kong, L. P. et al. Simultaneous band-gap narrowing and carrier-lifetime prolongation of organic–inorganic trihalide perovskites. Proc. Natl Acad. Sci. USA 113, 8910–8915 (2016).

    CAS  Article  Google Scholar 

  18. 18.

    Xiao, G. J. et al. Pressure effects on structure and optical properties in cesium lead bromide perovskite nanocrystals. J. Am. Chem. Soc. 139, 10087–10094 (2017).

    CAS  Article  Google Scholar 

  19. 19.

    Kubota, Y., Watanabe, K., Tsuda, O. & Taniguchi, T. Deep ultraviolet light-emitting hexagonal boron nitride synthesized at atmospheric pressure. Science 317, 932–934 (2007).

    CAS  Article  Google Scholar 

  20. 20.

    Cheng, H.-C. et al. Van der Waals heterojunction devices based on organohalide perovskites and two-dimensional materials. Nano. Lett. 16, 367–373 (2016).

    CAS  Article  Google Scholar 

  21. 21.

    Wu, X. X. et al. Trap states in lead iodide perovskites. J. Am. Chem. Soc. 135, 2089–2096 (2015).

    Article  Google Scholar 

  22. 22.

    Stébé, B., Assaid, E., Le Goff, S. & Dujardin, F. Giant oscillator strengths of ionized donor bound excitons in semiconductor quantum crystallites. Solid State Commun. 100, 217–220 (1996).

    Article  Google Scholar 

  23. 23.

    Dong, R. et al. High-gain and low-driving-voltage photodetectors based on organolead triiodide perovskties. Adv. Mater. 27, 1912–1918 (2015).

    CAS  Article  Google Scholar 

  24. 24.

    Kresse, G. & Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 47, 558–561 (1993).

    CAS  Article  Google Scholar 

  25. 25.

    Yin, Z. Y. et al. Single-layer MoS2 phototransistors. ACS Nano 6, 74–80 (2012).

    CAS  Article  Google Scholar 

  26. 26.

    Wang, X. D. et al. Ultrasensitive and broadband MoS2 photodetector driven by ferroelectrics. Adv. Mater. 27, 6575–6581 (2015).

    CAS  Article  Google Scholar 

  27. 27.

    Furchi, M. M., Polyushkin, D. K., Pospischil, A. & Mueller, T. Mechanisms of photoconductivity in atomically thin MoS2. Nano. Lett. 135, 2089–2096 (2015).

    Google Scholar 

  28. 28.

    Tan, Z. J. et al. Two-dimensional (C4H9NH3)2PbBr4 perovskite crystals for high-performance photodetector. J. Am. Chem. Soc. 138, 16612–16615 (2016).

    CAS  Article  Google Scholar 

  29. 29.

    Dou, L. et al. Solution-processed hybrid perovskite photodetectors with high detectivity. Nat. Commun. 5, 5404 (2014).

    CAS  Article  Google Scholar 

  30. 30.

    Guo, Q. S. et al. Black phosphorus mid-infrared photodetectors with high gain. Nano. Lett. 16, 4648–4655 (2016).

    CAS  Article  Google Scholar 

  31. 31.

    Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Crystallogr. Section C 71, 3–8 (2015).

    Google Scholar 

  32. 32.

    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).

    CAS  Article  Google Scholar 

  33. 33.

    Perdew, J. P. et al. Atoms, molecules, solids, and surfaces: applications of the generalized gradient approximation for exchange and correlation. Phys. Rev. B 46, 6671–6687 (1992).

    CAS  Article  Google Scholar 

  34. 34.

    Blöchl, P. E., Jepsen, O. & Andersen, O. K. Improved tetrahedron method for Brillouin-zone integrations. Phys. Rev. B 49, 16223–16233 (1994).

    Article  Google Scholar 

  35. 35.

    Grimme, S. Semiempirical GGA‐type density functional constructed with a long‐range dispersion correction. J. Comput. Chem. 27, 1787–1799 (2006).

    CAS  Article  Google Scholar 

Download references

Acknowledgements

K.L. thanks the Solar Energy Research Institute of Singapore (SERIS) for scholarship support. I.A. acknowledges the NUS–Imperial Joint PhD programme. K.P.L. acknowledges A* star DST funding under the project ‘Flexible and High Performance Based Perovskite Solar Cells on Graphene’ (no. R-143000-598-305). K.L. thanks I.-H. Park for help with solving single-crystal data, L. Wang for discussions of this work and H. Zhu for help with photoluminescence lifetime tests. G.E. acknowledges the Singapore Ministry of Education Tier 2 grant (MOE2015-T2-2-123).

Author information

Affiliations

Authors

Contributions

K.L. and K.P.L. conceived and designed the experiments. K.L. fabricated all RPP single crystals. K.L. and I.A. prepared all atomically thin samples and performed AFM measurements in the glove box. I.V. and K.L. tested the PC device. M.T. performed Q-plus nc-AFM scanning. K.L. and I.A. prepared samples for Q-plus nc-AFM scanning. K.L., L.Q.C. and I.A. performed photoluminescence measurements. I.A. and K.L. fabricated the devices. N.G. performed calculations. K.L. and K.P.L. wrote the manuscript. All authors contributed to the overall scientific interpretation.

Corresponding author

Correspondence to Kian Ping Loh.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information

Supplementary Text, Supplementary Figures 1–13, Supplementary Tables 1–8, Supplementary Reference 1

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Leng, K., Abdelwahab, I., Verzhbitskiy, I. et al. Molecularly thin two-dimensional hybrid perovskites with tunable optoelectronic properties due to reversible surface relaxation. Nature Mater 17, 908–914 (2018). https://doi.org/10.1038/s41563-018-0164-8

Download citation

Further reading

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