Hybrid nanocolloids with programmed three-dimensional shape and material composition

Journal name:
Nature Materials
Volume:
12,
Pages:
802–807
Year published:
DOI:
doi:10.1038/nmat3685
Received
Accepted
Published online

Tuning the optical1, 2, electromagnetic3, 4 and mechanical properties of a material requires simultaneous control over its composition and shape5. This is particularly challenging for complex structures at the nanoscale because surface-energy minimization generally causes small structures to be highly symmetric5. Here we combine low-temperature shadow deposition with nanoscale patterning to realize nanocolloids with anisotropic three-dimensional shapes, feature sizes down to 20 nm and a wide choice of materials. We demonstrate the versatility of the fabrication scheme by growing three-dimensional hybrid nanostructures that contain several functional materials with the lowest possible symmetry, and by fabricating hundreds of billions of plasmonic nanohelices, which we use as chiral metafluids with record circular dichroism and tunable chiroptical properties.

At a glance

Figures

  1. Fabrication scheme illustrated for nanohooks with C1 symmetry.
    Figure 1: Fabrication scheme illustrated for nanohooks with C1 symmetry.

    a,b, The 14 nm gold nanodots patterned by micellar nanolithography (a; bottom, SEM image of patterned wafer) act as nucleation sites (b) during subsequent shadow growth. c, Manipulation of the substrate angle and deposition material creates complex 3D structures. The growth process takes approximately 1 h. d, TEM image of hybrid insulator–metal nanohooks. e, Model of the designed structure, and TEM image showing the grown structure (inset). f,g, On sonication the nanoparticles are released into solution (schematic (f), photograph (g)).

  2. Seed size controls the nanostructure’s diameter.
    Figure 2: Seed size controls the nanostructure’s diameter.

    The histogram shows the distribution of rod diameters for SiO2 nanorods grown on seeds of diameter 14 nm (i), 17 nm (ii), 29 nm (iii) and 36 nm (iv). At least 100 nanoparticles were measured for each sample. Plots were normalized (total population  =  100) for convenient comparison. The inset shows the corresponding TEM images. Scale bars, 50 nm.

  3. Hybrid nanoparticles with progressively lower symmetry.
    Figure 3: Hybrid nanoparticles with progressively lower symmetry.

    Columns from left to right show: nano-barcodes, CS nano-zigzags combining magnetic, semiconducting and insulating materials, and the lowest possible symmetry C1 nanohooks with defined chirality. First row, structure models. TEM images (second row) and false-colour elemental maps (third row) of the same regions generated by analysing EF-TEM images using the three-window technique (Supplementary Note S9). Colour code (and corresponding core-loss edges): red, aluminium (Al L2,3 for nano-barcodes, Al K for nanohooks); blue, silver (Ag M4,5); yellow, titanium (Ti L2,3); green, silicon (Si L2,3); purple, nickel (Ni L2,3); cyan, copper (Cu L2,3).

  4. The chiroptical response of solutions of Au nanohelices.
    Figure 4: The chiroptical response of solutions of Au nanohelices.

    a, Model two-turn gold nanohelix showing critical dimensions. b, Normalized circular dichroism (CD) spectra of left-handed and right-handed helices. Inset: TEM images of grown structures with left (top) and right (bottom) chirality (image dimensions: 85 nm × 120 nm). c, Circular dichroism spectra of two- and one-turn helices grown under cooling conditions, and of nominal two-turn helices grown at room temperature. The spectra are plotted against an absolute y axis calibrated according to the optical density of the λmax peaks (at around 600 nm) in the corresponding ultraviolet–visible spectra. d, Simulated CD spectra for a based on model dimensions taken from TEM images. The insets show the discrete dipole models used in the calculations.

  5. Tuning the chiroptical response by composition and shape.
    Figure 5: Tuning the chiroptical response by composition and shape.

    a, Oblique-angle SEM image showing Ag:Cu (65:35) alloy helices as grown on wafer before release. b, Wide-field TEM image of the same Ag:Cu helices after deposition from solution onto TEM grid. c,d, TEM image of a single Ag:Cu alloy helix (c) and a Cu helix (d). Both helices are 92 nm tall with two turns. e, Suspension circular dichroism (CD) spectra. The CD response can be tailored by controlling the helix composition (Cu versus Ag:Cu alloy helices), and also by the helix size (Au 175 nm tall, two turns. The estimated nanoparticle concentration of Ag:Cu alloy helices is ~10−11 M (see Supplementary Section S5 for more details).

References

  1. Burda, C., Chen, X., Narayanan, R. & El-Sayed, M. A. Chemistry and properties of nanocrystals of different shapes. Chem. Rev. 105, 10251102 (2005).
  2. Choi, C. L. & Alivisatos, A. P. From artificial atoms to nanocrystal molecules: Preparation and properties of more complex nanostructures. Annu. Rev. Phys. Chem. 61, 369389 (2010).
  3. Albrecht, M. et al. Magnetic multilayers on nanospheres. Nature Mater. 4, 203206 (2005).
  4. Hentschel, M., Schäferling, M., Weiss, T., Liu, N. & Giessen, H. Three-dimensional chiral plasmonic oligomers. Nano Lett. 12, 25422547 (2012).
  5. Glotzer, S. C. & Solomon, M. J. Anisotropy of building blocks and their assembly into complex structures. Nature Mater. 6, 557562 (2007).
  6. Linic, S., Christopher, P. & Ingram, D. B. Plasmonic-metal nanostructures for efficient conversion of solar to chemical energy. Nature Mater. 10, 911921 (2011).
  7. Sun, S., Murray, C. B., Weller, D., Folks, L. & Moser, A. Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science 287, 19891992 (2000).
  8. Xia, Y., Xiong, Y., Lim, B. & Skrabalak, S. E. Shape-controlled synthesis of metal nanocrystals: Simple chemistry meets complex physics? Angew. Chem. Int. Ed. 48, 60103 (2009).
  9. Mann, S. Self-assembly and transformation of hybrid nano-objects and nanostructures under equilibrium and non-equilibrium conditions. Nature Mater. 8, 781792 (2009).
  10. Grzybowski, B. A., Wilmer, C. E., Kim, J., Browne, K. P. & Bishop, K. J. M. Self-assembly: From crystals to cells. Soft Matter. 5, 11101128 (2009).
  11. Seddon, A. M., Patel, H. M., Burkett, S. L. & Mann, S. Chiral templating of silica–lipid lamellar mesophase with helical tubular architecture. Angew. Chem. Int. Ed. 41, 29882991 (2002).
  12. Sone, E. D., Zubarev, E. R. & Stupp, S. I. Semiconductor nanohelices templated by supramolecular ribbons. Angew. Chem. Int. Ed. 41, 17051709 (2002).
  13. González, E., Arbiol, J. & Puntes, V. F. Carving at the nanoscale: Sequential galvanic exchange and kirkendall growth at room temperature. Science 334, 13771380 (2011).
  14. Qin, L., Park, S., Huang, L. & Mirkin, C. A. On-wire lithography. Science 309, 113115 (2005).
  15. Pires, D. et al. Nanoscale three-dimensional patterning of molecular resists by scanning probes. Science 328, 732735 (2010).
  16. Glass, R., Möller, M. & Spatz, J. P. Block copolymer micelle nanolithography. Nanotechnology 14, 11531160 (2003).
  17. Spatz, J. P. et al. Ordered deposition of inorganic clusters from micellar block copolymer films. Langmuir 16, 407415 (1999).
  18. Young, N. O. & Kowal, J. Optically active fluorite films. Nature 183, 104105 (1959).
  19. Robbie, K., Friedrich, L. J., Dew, S. K., Smy, T. & Brett, M. J. Fabrication of thin films with highly porous microstructures. J. Vac. Sci. Technol. A 13, 10321035 (1995).
  20. Hawkeye, M. M. & Brett, M. J. Glancing angle deposition: Fabrication, properties, and applications of micro- and nanostructured thin films. J. Vac. Sci. Technol. A 25, 13171335 (2007).
  21. Robbie, K., Brett, M. J. & Lakhtakia, A. Chiral sculptured thin films. Nature 384, 616616 (1996).
  22. Zhao, Y. P., Ye, D. X., Wang, G. C. & Lu, T. M. in Nanotubes and Nanowires 5219 (eds Lakhtakia, A. & Maksimenko, S.) 5973 (2003).
  23. Mokari, T., Sztrum, C. G., Salant, A., Rabani, E. & Banin, U. Formation of asymmetric one-sided metal-tipped semiconductor nanocrystal dots and rods. Nature Mater. 4, 855863 (2005).
  24. Algra, R. E. et al. Twinning superlattices in indium phosphide nanowires. Nature 456, 369372 (2008).
  25. Gansel, J. K. et al. Gold helix photonic metamaterial as broadband circular polarizer. Science 325, 15131515 (2009).
  26. Kuzyk, A. et al. DNA-based self-assembly of chiral plasmonic nanostructures with tailored optical response. Nature 483, 311314 (2012).
  27. Fan, Z. & Govorov, A. O. Chiral nanocrystals: Plasmonic spectra and circular dichroism. Nano Lett. 12, 32833289 (2012).
  28. Zhang, Z. Y. & Zhao, Y. P. Optical properties of helical and multiring Ag nanostructures: The effect of pitch height. J. Appl. Phys. 104, 013517013517 (2008).
  29. Moore, D. & Tinoco, J. I. The circular dichroism of large helices. A free particle on a helix. J. Chem. Phys. 72, 33963400 (1980).
  30. Draine, B. T. & Flatau, P. J. Discrete-dipole approximation for scattering calculations. J. Opt. Soc. Am. A 11, 14911499 (1994).
  31. Bruce, T. & Draine, P. J. F. User Guide for the Discrete Dipole Approximation Code DDSCAT 7.2. arXiv (2012).

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Author information

  1. These authors contributed equally to this work

    • Andrew G. Mark &
    • John G. Gibbs

Affiliations

  1. Max Planck Institute for Intelligent Systems, Heisenbergstraße 3, 70569 Stuttgart, Germany

    • Andrew G. Mark,
    • John G. Gibbs,
    • Tung-Chun Lee &
    • Peer Fischer

Contributions

J.G.G. and A.G.M. built the shadow growth set-up, and grew the nanostructures. T-C.L. prepared the nanocolloidal solutions and carried out the TEM imaging. A.M. undertook numerical calculations. P.F. proposed the experiment, and A.G.M., J.G.G., T-C.L. and P.F. analysed the data and wrote the paper.

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