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Nanostructured organic semiconductor films for molecular detection with surface-enhanced Raman spectroscopy

Nature Materials volume 16, pages 918924 (2017) | Download Citation

Abstract

π-Conjugated organic semiconductors have been explored in several optoelectronic devices, yet their use in molecular detection as surface-enhanced Raman spectroscopy (SERS)-active platforms is unknown. Herein, we demonstrate that SERS-active, superhydrophobic and ivy-like nanostructured films of a molecular semiconductor, α,ω-diperfluorohexylquaterthiophene (DFH-4T), can be easily fabricated by vapour deposition. DFH-4T films without any additional plasmonic layer exhibit unprecedented Raman signal enhancements up to 3.4 × 103 for the probe molecule methylene blue. The combination of quantum mechanical computations, comparative experiments with a fluorocarbon-free α,ω-dihexylquaterthiophene (DH-4T), and thin-film microstructural analysis demonstrates the fundamental roles of the π-conjugated core fluorocarbon substitution and the unique DFH-4T film morphology governing the SERS response. Furthermore, Raman signal enhancements up to 1010 and sub-zeptomole (<10−21 mole) analyte detection were accomplished by coating the DFH-4T films with a thin gold layer. Our results offer important guidance for the molecular design of SERS-active organic semiconductors and easily fabricable SERS platforms for ultrasensitive trace analysis.

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Acknowledgements

This work was partially supported by Gazi University (grant no. 05/2015-19) and Polyera Corporation. G.D., H.U. and Y.D. acknowledge support from the Turkish Academy of Sciences, Distinguished Young Scientist Award (TUBA-GEBIP). A.F. thanks the Shenzhen Peacock Plan project (KQTD20140630110339343) and the BSF (AGMT-2012250///02).

Author information

Affiliations

  1. Bio-inspired Materials Research Laboratory (BIMREL), Department of Chemistry, Gazi University, 06500 Ankara, Turkey

    • Mehmet Yilmaz
    • , Esra Babur
    •  & Gokhan Demirel
  2. Department of Bioengineering, Faculty of Engineering and Architecture, Sinop University, 57000 Sinop, Turkey

    • Mehmet Yilmaz
  3. Department of Materials Science and Nanotechnology Engineering, Abdullah Gül University, 38080 Kayseri, Turkey

    • Mehmet Ozdemir
    •  & Hakan Usta
  4. Department of Chemistry and the Materials Research Center, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA

    • Rebecca L. Gieseking
    • , George C. Schatz
    •  & Antonio Facchetti
  5. Theoretical/Computational Chemistry Research Laboratory, Department of Chemistry, Gazi University, 06500 Ankara, Turkey

    • Yavuz Dede
  6. Department of Analytical Chemistry, Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey

    • Ugur Tamer
  7. Flexterra Inc., 8025 Lamon Avenue, Skokie, 60077 Illinois, USA

    • Antonio Facchetti

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Contributions

G.D., H.U. and A.F. conceived and designed the experiments. H.U., M.Ö. and A.F. synthesized the small molecular organic semiconductors. G.D., M.Y., U.T. and E.B. fabricated the nanostructured platforms and performed the experiments. G.C.S. and R.L.G. designed and performed the theoretical calculations. Y.D. helped with the density functional theory calculations. All authors discussed the results and co-wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to George C. Schatz or Antonio Facchetti or Hakan Usta or Gokhan Demirel.

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DOI

https://doi.org/10.1038/nmat4957

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