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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.

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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.

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

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

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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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