Direct laser writing of random Au nanoparticle three-dimensional structures for highly reproducible micro-SERS measurements
Abstract
Fabrication of freestanding, three-dimensional microstructures having gold nanoparticles as building blocks
has been achieved using two-photon lithography. The reported constructions hold structural coherence
without the need of a polymeric network to embed the nanoparticles. The Au nanoparticles are
produced by radical-mediated photoreduction and immediately self-arrange in micrometre-sized
cylinders, which are used as the building units of the 3D structure writing. The manufactured structures
present plasmonic activity, as well as excellent properties as substrates for Surface-Enhanced Raman
Spectroscopy, in key issues such as reproducibility in intensity or enhancement factor. Such is calculated
to be above 8 106 for the non-resonant probe molecule trans-1,2-bis-4-pyridylethylene. The option
of repeated use of the substrates is confirmed, and they are successfully applied for detection of the
fungicide thiabendazole.