Paper BI+MI-WeM3
Hole-mask Colloidal Lithography Method to Fabricate Chiral Metal-Nanoparticles for Plasmon Enhanced CD Measurements

Wednesday, November 9, 2016, 8:40 am, Room 101A

Hole-mask colloidal lithography is a well studied method [1] for a reliable high throughput fabrication of metal nanoparticles (NP). The plasmonic resonances and their electromagnetic near field dependencies of such NPs are widely used as bio-sensors , e. g. for high sensitivity refractive index sensing [2]. Rather recently it was also shown that the near field interactions of planar plasmonic chiral NPs can be used for sensitive chiroptical measurements of very dilute amounts of chiral material [3], allowing structural characterization of even small amounts of many biomolecules. So far the fabrication of such chiral NPs is based on time-consuming techniques such as e-beam lithography [4].

Here, I present a novel method for the fabrication of chiral Au nanocrescents based on a modified version of hole-mask colloidal lithography. This reliable and efficient method utilizes the shrinking of the hole due to the material evaporated through it, adding an additional parameter to the control over the shape of the resulting NP.

The method allows the fabrication of nanocrescents with an outer diameter of 100nm-200nm that show plasmonic responses similar to previous Au structures [2]. Furthermore, when analyzed with circular polarized light, they show a considerable circular dichroism response.

Hence, this fabrication method is a promising technique for the time- and cost-efficient production of sensitive biosensors for the structural analysis of chiral materials.

[1] Bochenkov, V. E. and Sutherland, D. S. ” NanoLett, Vol. 13, 1216-1220, 2013.

[2] Guerreiro, J. R. L. et al. ACS nano, Vol. 8, No. 8, 7958–7967, 2014.

[3] Hendry, E. et al. NNANO, Vol. 5, 783-786, 2010.

[4] Hentschel, M. et al. NanoLett, Vol. 12, 2542-2547, 2012.