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Metallated conjugated polymers as a new avenue towards high-efficiency polymer solar cells

Nature Materials volume 6, pages 521–527 (2007)Cite this article

Abstract

Bulk heterojunction solar cells have been extensively studied owing to their great potential for cost-effective photovoltaic devices. Although recent advances resulted in the fabrication of poly(3-hexylthiophene) (P3HT)/fullerene derivative based solar cells with efficiencies in the range 4.4–5.0%, theoretical calculations predict that the development of novel donor materials with a lower bandgap is required to exceed the power-conversion efficiency of 10%. However, all of the lower bandgap polymers developed so far have failed to reach the efficiency of P3HT-based cells. To address this issue, we synthesized a soluble, intensely coloured platinum metallopolyyne with a low bandgap of 1.85 eV. The solar cells, containing metallopolyyne/fullerene derivative blends as the photoactive material, showed a power-conversion efficiency with an average of 4.1%, without annealing or the use of spacer layers needed to achieve comparable efficiency with P3HT. This clearly demonstrates the potential of metallated conjugated polymers for efficient photovoltaic devices.

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Figure 1: Synthesis scheme of low-bandgap organometallic diyne and polyyne and solid-state structure of M1.
Figure 2: Optical properties of L1, P1 and M1.
Figure 3: J–V curves of solar cells with P1/PCBM (1:4) and P3HT/PCBM (1:4) active layers.
Figure 4: AFM images of P1/PCBM films for different blend compositions.
Figure 5: Comparison of P1/PCBM and P3HT/PCBM blends.
Figure 6: Performance of the P1/PCBM device for different illumination powers.

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Acknowledgements

This work was supported by the Research Grants Council of The Hong Kong Special Administrative Region, China (Project Numbers HKBU 2024/04P, HKU 7008/04P and 7010/05P). Financial support from the Hong Kong Baptist University, the Strategic Research Theme, University Development Fund, a Seed Funding Grant and an Outstanding Young Researcher Award (administrated by The University of Hong Kong) are also acknowledged. The authors would like to thank J. Gao from the University of Hong Kong for step-profiler thickness measurements, A. M. C. Ng for ellipsometry measurements and W. C. H. Choy and HKU-CAS Joint Laboratory on New Materials and C. M. Che for the use of a glove box for encapsulation. The authors would also like to thank R. de Bettignies and S. Guillerez from CEA-INES RDI, Laboratoire Composants Solaires, in Bourges Du Lac, France for independent verification of the solar-cell results.

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Authors and Affiliations

  1. Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, PR China

    Wai-Yeung Wong, Xing-Zhu Wang & Ze He

  2. Centre for Advanced Luminescence Materials, Hong Kong Baptist University, Waterloo Road, Kowloon Tong, Hong Kong, PR China

    Wai-Yeung Wong

  3. Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China

    Aleksandra B. Djurišić, Cho-Tung Yip, Kai-Yin Cheung & Hai Wang

  4. Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, PR China

    Chris S. K. Mak & Wai-Kin Chan

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Contributions

X.-Z.W. and Z.H. were responsible for the synthesis and chemical analyses, C.-T.Y., K.-Y.C., H.W. and C.S.-K.M. carried out film and device fabrication and characterization, C.-T.Y., C.S.-K.M., A.B.D., W.-K.C. and W.-Y.W. were responsible for data analysis and interpretation, W.-Y.W., A.B.D. and W.-K.C. were responsible for project planning and experiment design and W.-Y.W. and A.B.D. were responsible for manuscript preparation.

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Correspondence to Wai-Yeung Wong or Aleksandra B. Djurišić.

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Supplementary information, figures S1-S6 and table S1 (PDF 305 kb)

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Wong, WY., Wang, XZ., He, Z. et al. Metallated conjugated polymers as a new avenue towards high-efficiency polymer solar cells. Nature Mater 6, 521–527 (2007). https://doi.org/10.1038/nmat1909

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