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Ti1–graphene single-atom material for improved energy level alignment in perovskite solar cells

Nature Energy volume 6, pages 1154–1163 (2021)Cite this article

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Abstract

Carbon-based perovskite solar cells (C-PSCs) are widely accepted as stable, cost-effective photovoltaics. However, C-PSCs have been suffering from relatively low power conversion efficiencies (PCEs) due to severe electrode-related energy loss. Herein, we report the application of a single-atom material (SAM) as the back electrode in C-PSCs. Our Ti1–rGO consists of single titanium (Ti) adatoms anchored on reduced graphene oxide (rGO) in a well-defined Ti1O4-OH configuration capable of tuning the electronic properties of rGO. The downshift of the Fermi level notably minimizes the series resistance of the carbon-based electrode. By combining with an advanced modular cell architecture, a steady-state PCE of up to 20.6% for C-PSCs is finally achieved. Furthermore, the devices without encapsulation retain 98% and 95% of their initial values for 1,300 h under 1 sun of illumination at 25°C and 60 °C, respectively.

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Fig. 1: Structural characterizations of Ti1–rGO.
Fig. 2: Coordination structure analysis of Ti atom in Ti1–rGO.
Fig. 3: Mechanistical insight into tuning the electric properties of Ti1–rGO electrode.
Fig. 4: Photovoltaic performance and operational stability.

Data availability

The datasets analysed and generated during the current study are included in the paper and its Supplementary Information. Source data are provided with this paper.

References

  1. NREL. Best research cell efficiency chart. http://www.nrel.gov/pv/cell-efficiency.html (2021).

  2. Khenkin, M. V. et al. Consensus statement for stability assessment and reporting for perovskite photovoltaics based on ISOS procedures. Nat. Energy 5, 35–49 (2020).

    Article  Google Scholar 

  3. Zheng, X. et al. Managing grains and interfaces via ligand anchoring enables 22.3%-efficiency inverted perovskite solar cells. Nat. Energy 5, 131–140 (2020).

    Article  Google Scholar 

  4. Tress, W. et al. Performance of perovskite solar cells under simulated temperature-illumination real-world operating conditions. Nat. Energy 4, 568–574 (2019).

    Article  Google Scholar 

  5. Jiang, Y. et al. Reduction of lead leakage from damaged lead halide perovskite solar modules using self-healing polymer-based encapsulation. Nat. Energy 4, 585–593 (2019).

    Article  Google Scholar 

  6. Guerrero, A. et al. Interfacial degradation of planar lead halide perovskite solar cells. ACS Nano 10, 218–224 (2016).

    Article  Google Scholar 

  7. Rong, Y. et al. Challenges for commercializing perovskite solar cells. Science 361, eaat8235 (2018).

    Article  Google Scholar 

  8. Wang, R. et al. A review of perovskites solar cell stability. Adv. Funct. Mater. 29, 1808843 (2019).

    Article  Google Scholar 

  9. Domanski, K. et al. Not all that glitters is gold: metal-migration-induced degradation in perovskite solar cells. ACS Nano 10, 6306–6314 (2016).

    Article  Google Scholar 

  10. 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 

  11. Rong, Y. et al. Synergy of ammonium chloride and moisture on perovskite crystallization for efficient printable mesoscopic solar cells. Nat. Commun. 8, 14555 (2017).

    Article  Google Scholar 

  12. Mei, A. et al. A hole-conductor-free, fully printable mesoscopic perovskite solar cell with high stability. Science 345, 295–298 (2014).

    Article  Google Scholar 

  13. Zhang, H. Y. et al. Self-adhesive macroporous carbon electrodes for efficient and stable perovskite solar cells. Adv. Funct. Mater. 28, 1802985 (2018).

    Article  Google Scholar 

  14. Zhang, C. et al. Efficient stable graphene-based perovskite solar cells with high flexibility in device assembling via modular architecture design. Energy Environ. Sci. 12, 3585–3594 (2019).

    Article  Google Scholar 

  15. Yan, K. et al. High-performance graphene-based hole conductor-free perovskite solar cells: Schottky junction enhanced hole extraction and electron blocking. Small 11, 2269–2274 (2015).

    Article  Google Scholar 

  16. Zhu, Y. et al. Facile synthesis of nitrogen-doped graphene frameworks for enhanced performance of hole transport material-free perovskite solar cells. J. Mater. Chem. C. 6, 3097–3103 (2018).

    Article  Google Scholar 

  17. Hadadian, M., Smått, J.-H. & Correa-Baena, J.-P. The role of carbon-based materials in enhancing the stability of perovskite solar cells. Energy Environ. Sci. 5, 1377–1407 (2020).

  18. Arora, N. et al. Low-cost and highly efficient carbon-based perovskite solar cells exhibiting excellent long-term operational and UV stability. Small 15, 1904746 (2019).

    Article  Google Scholar 

  19. Zheng, X. et al. Boron doping of multiwalled carbon nanotubes significantly enhances hole extraction in carbon-based perovskite solar cells. Nano Lett. 17, 2496–2505 (2017).

    Article  Google Scholar 

  20. Wu, Z. et al. Highly efficient and stable perovskite solar cells via modification of energy levels at the perovskite/carbon electrode interface. Adv. Mater. 31, 1804284 (2019).

  21. You, P., Liu, Z., Tai, Q., Liu, S. & Yan, F. Efficient semitransparent perovskite solar cells with graphene electrodes. Adv. Mater. 27, 3632–3638 (2015).

    Article  Google Scholar 

  22. Zhou, J. et al. Semi-transparent Cl-doped perovskite solar cells with graphene electrodes for tandem application. Mater. Lett. 220, 82–85 (2018).

    Article  Google Scholar 

  23. Lang, F. et al. In situ graphene doping as a route toward efficient perovskite tandem solar cells. Phys. Status Solidi (A) 213, 1989–1996 (2016).

    Article  Google Scholar 

  24. Chen, M. et al. Boron and phosphorus co-doped carbon counter electrode for efficient hole-conductor-free perovskite solar cell. Chem. Eng. J. 313, 791–800 (2017).

    Article  Google Scholar 

  25. Chee, S. S. et al. Lowering the Schottky barrier height by graphene/Ag electrodes for high-mobility MoS2 field-effect transistors. Adv. Mater. 31, 1804422 (2019).

    Article  Google Scholar 

  26. Kwon, K. C., Choi, K. S. & Kim, S. Y. Increased work function in few-layer graphene sheets via metal chloride doping. Adv. Funct. Mater. 22, 4724–4731 (2012).

    Article  Google Scholar 

  27. Zhou, S. et al. Pd single-atom catalysts on nitrogen-doped graphene for the highly selective photothermal hydrogenation of acetylene to ethylene. Adv. Mater. 31, 1900509 (2019).

    Article  Google Scholar 

  28. Peng, P. et al. A pyrolysis-free path toward superiorly catalytic nitrogen-coordinated single atom. Sci. Adv. 5, eaaw2322 (2019).

    Article  Google Scholar 

  29. Chen, G. et al. Zinc-mediated template synthesis of Fe-N-C electrocatalysts with densely accessible Fe-Nx active sites for efficient oxygen reduction. Adv. Mater. 32, 1907399 (2020).

  30. Jiao, L. & Jiang, H.-L. Metal-organic-framework-based single-atom catalysts for energy applications. Chem. 5, 786–804 (2019).

  31. Xiang, H., Feng, W. & Chen, Y. Single-atom catalysts in catalytic biomedicine. Adv. Mater. 32, 1905994 (2020).

  32. Samantaray, M. K. et al. The comparison between single atom catalysis and surface organometallic catalysis. Chem. Rev. 120, 734–813 (2019).

  33. Huang, L., Chen, J., Gan, L., Wang, J. & Dong, S. Single-atom nanozymes. Sci. Adv. 5, eaav5490 (2019).

    Article  Google Scholar 

  34. Guan, J. et al. Water oxidation on a mononuclear manganese heterogeneous catalyst. Nat. Catal. 1, 870–877 (2018).

    Article  Google Scholar 

  35. Zhang, B. et al. Manganese acting as a high-performance heterogeneous electrocatalyst in carbon dioxide reduction. Nat. Commun. 10, 2980 (2019).

    Article  Google Scholar 

  36. Gu, J., Hsu, C.-S., Bai, L., Chen, H. M. & Hu, X. Atomically dispersed Fe3+ sites catalyze efficient CO2 electroreduction to CO. Science 364, 1091–1094 (2019).

    Article  Google Scholar 

  37. Zhu, H. et al. Tailored amphiphilic molecular mitigators for stable perovskite solar cells with 23.5% efficiency. Adv. Mater. 32, 1907757 (2020).

    Article  Google Scholar 

  38. Wolf, M. & Rauschenbach, H. Series resistance effects on solar cell measurements. Adv. Energy Conv. 3, 455–479 (1963).

    Article  Google Scholar 

  39. Mundhaas, N. et al. Series resistance measurements of perovskite solar cells using Jsc-Voc measurements. Sol. RRL 3, 1800378 (2019).

    Article  Google Scholar 

  40. Zhang, C. et al. Room-temperature solution-processed amorphous NbOx as an electron transport layer in high-efficiency photovoltaics. J. Mater. Chem. A. 6, 17882–17888 (2018).

    Article  Google Scholar 

  41. Cai, X. et al. Revealing atomic structure and oxidation states of dopants in charge-ordered nanoparticles for migration-promoted oxygen-exchange capacity. Chem. Mater. 31, 5769–5777 (2019).

    Article  Google Scholar 

  42. Cueva, P., Hovden, R., Mundy, J. A., Xin, H. L. & Muller, D. A. Data processing for atomic resolution electron energy loss spectroscopy. Microsc. Microanal. 18, 667–675 (2012).

    Article  Google Scholar 

  43. Newville, M. IFEFFIT: interactive XAFS analysis and FEFF fitting. J. Synchrotron Radiat. 8, 322–324 (2001).

    Article  Google Scholar 

  44. Ravel, B. & Newville, M. ATHENA, ARTEMIS, HEPHAESTUS: data analysis for X-ray absorption spectroscopy using IFEFFIT. J. Synchrotron Radiat. 12, 537–541 (2005).

    Article  Google Scholar 

  45. Ankudinov, A. L., Ravel, B., Rehr, J. & Conradson, S. Real-space multiple-scattering calculation and interpretation of x-ray-absorption near-edge structure. Phys. Rev. B. 58, 7565 (1998).

    Article  Google Scholar 

  46. 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).

    Article  Google Scholar 

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

    Article  Google Scholar 

Download references

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (grant nos. 51872036, 51773025, 11504046), LiaoNing Revitalization Talents Program (grant nos. XLYC2007038, XLYC2008032), Dalian science and technology innovation fund (grant nos. 2018J12GX033, 2019J12GX032) and special funds for science and technology development under the guidance of the central government (grant no. 2021JH6/10500152). N.W. thanks the financial support from the Hong Kong Research Grants Council (project nos. 16306818 and N_HKUST624/19). C.Zhang thanks the Chinese Scholarship Council for their financial support to his in-split PhD study in Switzerland. M.G. thanks the financial support from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 881603.

Author information

Author notes

  1. These authors contributed equally: Chunyang Zhang, Suxia Liang, Wei Liu.

Authors and Affiliations

  1. State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of Technology, Dalian, China

    Chunyang Zhang, Wei Liu, Yudi Wang, Jinwen Hu, Hongru Ma, Cuncun Xin & Yantao Shi

  2. Laboratory of Photonics and Interfaces, Department of Chemistry and Chemical Engineering, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

    Chunyang Zhang, Felix T. Eickemeyer, Hongwei Zhu, Shaik Mohammed Zakeeruddin & Michael Grätzel

  3. State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China

    Suxia Liang & Jiangwei Zhang

  4. Department of Physics, Hong Kong University of Science and Technology, Kowloon, China

    Xiangbin Cai & Ning Wang

  5. Department of Chemistry & College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China

    Ke Zhou

  6. Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology, Dalian, China

    Jiming Bian

  7. SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Collaborative Innovation Center for Micro/Nano Fabrication, Device and System, Southeast University, Nanjing, China

    Chao Zhu

  8. Laboratory of Photomolecular Science, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland

    Zaiwei Wang

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  1. Chunyang Zhang
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Contributions

Y.S. and C.Zhang proposed the idea, designed the project and organized the manuscript, C.Zhang carried out the experiments including material characterizations, device fabrication and measurements. M.G. supervised the experimental investigation and manuscript modification. C.Zhu contributed to material design, STEM characterization, structure analysis and manuscript preparation. W.L. conducted XANES and EXAFS measurements and analysed the chemical structure of Ti1–rGO. S.L. prepared Ti1–rGO and conducted DFT calculations. F.T.E. conducted and interpreted the Jsc–Voc measurements. X.C. and N.W. conducted and interpreted the EELS characterization. S.M.Z. helped on manuscript organization and project coordination. K.Z. conducted the HTEM, EDX mapping characterizations and XAFS measurements. J.B. contributed to the analysis of the characterizations around interface. H.Z. helped on the device fabrication. Z.W. modified the manuscript. J.Z analysed the chemical structure of Ti1–rGO. Y.W. contributed to mechanical pressure measurement. J.H., C.X. and H.M. helped with material preparations and XPS/UPS characterizations. All authors contributed to results discussion and writing.

Corresponding authors

Correspondence to Chao Zhu, Michael Grätzel or Yantao Shi.

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Peer review information Nature Energy thanks Andreas Hinsch and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

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Supplementary information

Supplementary Information

Supplementary Figs. 1–21, Notes 1–6 and Tables 1–8.

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Source data

Source Data Fig. 2

Numerical data used to generate Fig. 2.

Source Data Fig. 3

Numerical data used to generate Fig. 3a–e.

Source Data Fig. 4

Numerical data used to generate Fig. 4b–g.

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Zhang, C., Liang, S., Liu, W. et al. Ti1–graphene single-atom material for improved energy level alignment in perovskite solar cells. Nat Energy 6, 1154–1163 (2021). https://doi.org/10.1038/s41560-021-00944-0

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