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A molecularly engineered hole-transporting material for efficient perovskite solar cells

Abstract

Solution-processable perovskite solar cells have recently achieved certified power conversion efficiencies of over 20%, challenging the long-standing perception that high efficiencies must come at high costs. One major bottleneck for increasing the efficiency even further is the lack of suitable hole-transporting materials, which extract positive charges from the active light absorber and transmit them to the electrode. In this work, we present a molecularly engineered hole-transport material with a simple dissymmetric fluorene–dithiophene (FDT) core substituted by N,N-di-p-methoxyphenylamine donor groups, which can be easily modified, providing the blueprint for a family of potentially low-cost hole-transport materials. We use FDT on state-of-the-art devices and achieve power conversion efficiencies of 20.2% which compare favourably with control devices with 2,2,7,7-tetrakis(N,N-di-p-methoxyphenylamine)-9,9-spirobifluorene (spiro-OMeTAD). Thus, this new hole transporter has the potential to replace spiro-OMeTAD.

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Figure 1: XRD and simulation data of FDT.
Figure 2: Optical characterization and energy levels of FDT and spiro.
Figure 3: Cross-sectional image of a full device together with the champion efficiencies of FDT and spiro.

References

  1. 1

    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 

  2. 2

    Ogomi, Y. et al. CH3NH3SnxPb(1−x)I3 perovskite solar cells covering up to 1060 nm. J. Phys. Chem. Lett. 5, 1004–1011 (2014).

    Article  Google Scholar 

  3. 3

    Oga, H., Saeki, A., Ogomi, Y., Hayase, S. & Seki, S. Improved understanding of the electronic and energetic landscapes of perovskite solar cells: high local charge carrier mobility, reduced recombination, and extremely shallow traps. J. Am. Chem. Soc. 136, 13818–13825 (2014).

    Article  Google Scholar 

  4. 4

    Xing, G. C. et al. Low-temperature solution-processed wavelength-tunable perovskites for lasing. Nature Mater. 13, 476–480 (2014).

    Article  Google Scholar 

  5. 5

    Saliba, M. et al. Structured organic–inorganic perovskite toward a distributed feedback laser. Adv. Mater. http://doi.org/f3j7p7 (2015).

  6. 6

    Tan, Z. K. et al. Bright light-emitting diodes based on organometal halide perovskite. Nature Nanotech. 9, 687–692 (2014).

    Article  Google Scholar 

  7. 7

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

    Article  Google Scholar 

  8. 8

    Domanski, K. et al. Working principles of perovskite photodetectors: analyzing the interplay between photoconductivity and voltage-driven energy-level alignment. Adv. Functional Mater. 25, 6936–6947 (2015).

    Article  Google Scholar 

  9. 9

    Albrecht, S. et al. Monolithic perovskite/silicon-heterojunction tandem solar cells processed at low temperature. Energy Environ. Sci. 9, 81–88 (2016).

    Article  Google Scholar 

  10. 10

    Baena, J. P. C. et al. Highly efficient planar perovskite solar cells through band alignment engineering. Energy Environ. Sci. 8, 2928–2934 (2015).

    Article  Google Scholar 

  11. 11

    Bailie, C. D. et al. Semi-transparent perovskite solar cells for tandems with silicon and CIGS. Energy Environ. Sci. 8, 956–963 (2015).

    Article  Google Scholar 

  12. 12

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

    Article  Google Scholar 

  13. 13

    Saliba, M. et al. Influence of thermal processing protocol upon the crystallization and photovoltaic performance of organic–inorganic lead trihalide perovskites. J. Phys. Chem. C 118, 17171–17177 (2014).

    Article  Google Scholar 

  14. 14

    Saliba, M. et al. Plasmonic-induced photon recycling in metal halide perovskite solar cells. Adv. Funct. Mater. 25, 5038–5046 (2015).

    Article  Google Scholar 

  15. 15

    Horantner, M. T., Zhang, W., Saliba, M., Wojciechowski, K. & Snaith, H. J. Templated microstructural growth of perovskite thin films via colloidal monolayer lithography. Energy Environ. Sci. 8, 2041–2047 (2015).

    Article  Google Scholar 

  16. 16

    Burschka, J. et al. Sequential deposition as a route to high-performance perovskite-sensitized solar cells. Nature 499, 316–319 (2013).

    Article  Google Scholar 

  17. 17

    Malinkiewicz, O. et al. Perovskite solar cells employing organic charge-transport layers. Nature Photon. 8, 128–132 (2014).

    Article  Google Scholar 

  18. 18

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

    Article  Google Scholar 

  19. 19

    Ahn, N. et al. Highly reproducible perovskite solar cells with average efficiency of 18.3% and best efficiency of 19.7% fabricated via Lewis base adduct of lead(II) iodide. J. Am. Chem. Soc. 137, 8696–8699 (2015).

    Article  Google Scholar 

  20. 20

    Bach, U. et al. Solid-state dye-sensitized mesoporous TiO2 solar cells with high photon-to-electron conversion efficiencies. Nature 395, 583–585 (1998).

    Article  Google Scholar 

  21. 21

    Murray, A. T. et al. Modular design of SPIRO-OMeTAD analogues as hole transport materials in solar cells. Chem. Commun. 51, 8935–8938 (2015).

    Article  Google Scholar 

  22. 22

    Abate, A. et al. Silolothiophene-linked triphenylamines as stable hole transporting materials for high efficiency perovskite solar cells. Energy Environ. Sci. 8, 2946–2953 (2015).

    Article  Google Scholar 

  23. 23

    Ganesan, P. et al. A simple spiro-type hole transporting material for efficient perovskite solar cells. Energy Environ. Sci. 8, 1986–1991 (2015).

    Article  Google Scholar 

  24. 24

    Jeon, N. J. et al. o-Methoxy substituents in Spiro-OMeTAD for efficient inorganic–organic hybrid perovskite solar cells. J. Am. Chem. Soc. 136, 7837–7840 (2014).

    Article  Google Scholar 

  25. 25

    Liu, J. et al. A dopant-free hole-transporting material for efficient and stable perovskite solar cells. Energy Environ. Sci. 7, 2963–2967 (2014).

    Article  Google Scholar 

  26. 26

    Zheng, L. L. et al. A hydrophobic hole transporting oligothiophene for planar perovskite solar cells with improved stability. Chem. Commun. 50, 11196–11199 (2014).

    Article  Google Scholar 

  27. 27

    Petrus, M. L., Bein, T., Dingemans, T. J. & Docampo, P. A low cost azomethine-based hole transporting material for perovskite photovoltaics. J. Mater. Chem. A 3, 12159–12162 (2015).

    Article  Google Scholar 

  28. 28

    Ito, S., Tanaka, S. & Nishino, H. Lead-halide perovskite solar cells by CH3NH3I dripping on Pbl(2)–CH(3)NH(3)l-DMSO precursor layer for planar and porous structures using CuSCN hole-transporting material. J. Phys. Chem. Lett. 6, 881–886 (2015).

    Article  Google Scholar 

  29. 29

    Zhao, D. W. et al. High-efficiency solution-processed planar perovskite solar cells with a polymer hole transport layer. Adv. Energy Mater. 5, 1401855 (2015).

    Article  Google Scholar 

  30. 30

    Krishna, A. et al. Novel hole transporting materials based on triptycene core for high efficiency mesoscopic perovskite solar cells. Chem. Sci. 5, 2702–2709 (2014).

    Article  Google Scholar 

  31. 31

    Krishna, A. et al. Facile synthesis of a furan-arylamine hole-transporting material for high-efficiency, mesoscopic perovskite solar cells. Chemistry 21, 15113–15117 (2015).

    Article  Google Scholar 

  32. 32

    Li, H. R. et al. A simple 3,4-ethylenedioxythiophene based hole-transporting material for perovskite solar cells. Angew. Chem. Int. Ed. 53, 4085–4088 (2014).

    Article  Google Scholar 

  33. 33

    Lim, I. et al. Indolocarbazole based small molecules: an efficient hole transporting material for perovskite solar cells. RSC Adv. 5, 55321–55327 (2015).

    Article  Google Scholar 

  34. 34

    Ball, J. M. et al. Optical properties and limiting photocurrent of thin-film perovskite solar cells. Energy Environ. Sci. 8, 602–609 (2015).

    Article  Google Scholar 

  35. 35

    Pozzi, G. et al. Synthesis and Photovoltaic Applications of a 4,4-Spirobi[cyclopenta[2,1-b;3,4-b]dithiophene]-bridged donor/acceptor dye. Org. Lett. 15, 4642–4645 (2013).

    Article  Google Scholar 

  36. 36

    Malinauskas, T. et al. Enhancing thermal stability and lifetime of solid-state dye-sensitized solar cells via molecular engineering of the hole-transporting material Spiro-OMeTAD. ACS Appl. Mater. Inter. 7, 11107–11116 (2015).

    Article  Google Scholar 

  37. 37

    Torres, A. & Rego, L. G. C. Surface effects and adsorption of methoxy anchors on hybrid lead iodide perovskites: insights for Spiro-MeOTAD attachment. J. Phys. Chem. C 118, 26947–26954 (2014).

    Article  Google Scholar 

  38. 38

    Yin, J. et al. Interfacial charge transfer anisotropy in polycrystalline lead iodide perovskite films. J. Phys. Chem. Lett. 6, 1396–1402 (2015).

    Article  Google Scholar 

  39. 39

    Pastore, M., Mosconi, E. & De Angelis, F. Computational investigation of dye-iodine interactions in organic dye-sensitized solar cells. J. Phys. Chem. C 116, 5965–5973 (2012).

    Article  Google Scholar 

  40. 40

    Umari, P., Mosconi, E. & De Angelis, F. Relativistic GW calculations on CH3NH3PbI3 and CH3NH3SnI3 perovskites for solar cell applications. Sci. Rep. 4, 4467 (2014).

    Article  Google Scholar 

  41. 41

    Abate, A. et al. Lithium salts as “redox active” p-type dopants for organic semiconductors and their impact in solid-state dye-sensitized solar cells. Phys. Chem. Chem. Phys. 15, 2572–2579 (2013).

    Article  Google Scholar 

  42. 42

    Unger, E. L. et al. Hysteresis and transient behavior in current–voltage measurements of hybrid-perovskite absorber solar cells. Energy Environ. Sci. 7, 3690–3698 (2014).

    Article  Google Scholar 

  43. 43

    Christians, J. A., Manser, J. S. & Kamat, P. V. Best practices in perovskite solar cell efficiency measurements. Avoiding the error of making bad cells look good. J. Phys. Chem. Lett. 6, 852–857 (2015).

    Article  Google Scholar 

  44. 44

    Sheng, R. et al. Methylammonium lead bromide perovskite-based solar cells by vapor-assisted deposition. J. Phys. Chem. C 119, 3545–3549 (2015).

    Article  Google Scholar 

  45. 45

    Chueh, C. C. et al. Non-halogenated solvents for environmentally friendly processing of high-performance bulk-heterojunction polymer solar cells. Energy Environ. Sci. 6, 3241–3248 (2013).

    Article  Google Scholar 

  46. 46

    Osedach, T. P., Andrew, T. L. & Bulovic, V. Effect of synthetic accessibility on the commercial viability of organic photovoltaics. Energy Environ. Sci. 6, 711–718 (2013).

    Article  Google Scholar 

  47. 47

    Becke, A. D. Density—functional thermochemistry. III. The role of exact exchange. J. Chem. Phys. 98, 5648–5652 (1993).

    Article  Google Scholar 

  48. 48

    Petersson, G. A. & Al-Laham, M. A. A complete basis set model chemistry. II. Open-shell systems and the total energies of the first-row atoms. J. Chem. Phys. 94, 6081–6090 (1991).

    Article  Google Scholar 

  49. 49

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

    Article  Google Scholar 

  50. 50

    Soler, J. M. et al. The SIESTA method for ab initio order-N materials simulation. J. Phys. Condens. Matter 14, 2745–2779 (2002).

    Article  Google Scholar 

  51. 51

    Wu, Z. G. & Cohen, R. E. More accurate generalized gradient approximation for solids. Phys. Rev. B 73, 235116 (2006).

    Article  Google Scholar 

  52. 52

    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 

  53. 53

    Mosconi, E., Ronca, E. & De Angelis, F. First-principles investigation of the TiO2/organohalide perovskites interface: the role of interfacial chlorine. J. Phys. Chem. Lett. 5, 2619–2625 (2014).

    Article  Google Scholar 

  54. 54

    Mitzi, D. B. Solution-processed inorganic semiconductors. J. Mater. Chem. 14, 2355–2365 (2004).

    Article  Google Scholar 

  55. 55

    Marzari, G. et al. Fluorous molecules for dye-sensitized solar cells: synthesis and characterization of fluorene-bridged donor/acceptor dyes with bulky perfluoroalkoxy substituents. J. Phys. Chem. C 116, 21190–21200 (2012).

    Article  Google Scholar 

  56. 56

    Zhang, X., Han, J. B., Li, P. F., Ji, X. & Zhang, Z. Improved, highly efficient, and green synthesis of bromofluorenones and nitrofluorenones in water. Synth. Commun. 39, 3804–3815 (2009).

    Article  Google Scholar 

  57. 57

    Jeux, V., Dalinot, C., Allain, M., Sanguinet, L. & Leriche, P. Synthesis of Spiro[cyclopenta[1,2-b:5,4-b]DiThiophene-4,9-Fluorenes] SDTF dissymmetrically functionalized. Tetrahedron Lett. 56, 1383–1387 (2015).

    Article  Google Scholar 

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Acknowledgements

This work was supported by the European Union Seventh Framework Programme [FP7/2007–2013] under grant agreement no 604032 of the MESO project, (FP7/2007–2013) ENERGY.2012.10.2.1; NANOMATCELL, grant agreement no. 308997. M.K.N. acknowledges funding by the Swiss National Science Foundation under NRP 70, grant No: 407040_154056, and MG Nanotera. We thank A. Wakamiya, Institute for Chemical Research, Kyoto University Uji, Kyoto 611-0011, Japan, F. Giordano for experimental help with lithium doping of the TiO2 scaffold, and T. Schmaltz for helpful discussions.

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Authors

Contributions

M.S. and T.M. conceived and designed the experiments, including fabrication and measurement of the PV devices. M.S. conducted DSC and TGA measurements. S.O., M.C. and G.P. designed and synthesized the FDT hole-transporting material. S.A. and P.G. developed crystals and characterized the FDT. J.-P.C.-B. and A.A. optimized TiO2 photoanodes, the perovskite films and characterized SEM. E.M. and F.D.A. performed first-principles calculations. R.S. analysed single crystals. M.S. wrote the first draft of the paper. All the authors contributed to the discussion and the writing of the paper, and approved. M.K.N. directed the scientific research for this work.

Corresponding author

Correspondence to Mohammad Khaja Nazeeruddin.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

Supplementary Notes 1-3, Supplementary Figures 1-14, Supplementary Tables 1-6, Supplementary References. (PDF 2081 kb)

Supplementary Data

Crystallographic data for compound FDT. (CIF 376 kb)

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Saliba, M., Orlandi, S., Matsui, T. et al. A molecularly engineered hole-transporting material for efficient perovskite solar cells. Nat Energy 1, 15017 (2016). https://doi.org/10.1038/nenergy.2015.17

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