Pooria Golvari1,Tyrone Morales1,Stephen Kuebler1,Jimmy Touma2
University of Central Florida1,Air Force Research Laboratory2
Pooria Golvari1,Tyrone Morales1,Stephen Kuebler1,Jimmy Touma2
University of Central Florida1,Air Force Research Laboratory2
Periodic assemblies of gold-nanoparticle (AuNP) clusters are attractive as tunable substrates for surface-enhanced Raman spectroscopy (SERS)<sup>1</sup>, as well as analyte sensors based on coupled localized surface plasmon resonance (LSPR)<sup>2</sup> and diffractively-coupled plasmonic surface lattice resonances (SLR)<sup>3, 4</sup>. We report an approach for fabricating two-dimensional lattices selectively filled with mono- or multi-layers of AuNP films. The lattices are prepared using e-beam lithography and then transferring the pattern into fused silica by reactive ion etching. Centrifuge-aided deposition assisted by a protein binder is then used to load dense mono- and multi-layers of AuNPs into the silica arrays, in one tenth of the time required for immersion methods. Post-assembly cross-linking of the binder prior to drying the AuNP film is used to control the spacing between the deposited layers and to tune the LSPR coupling. Masking and lift-off can be used to selectively deposit AuNP-clusters inside the prepatterned arrays. The AuNP-filled arrays are optically characterized in reflection and transmission modes in the visible and near-infrared. The method provides a means for independently controlling properties of the AuNP-clusters (e.g., size and interparticle spacing) and properties of the lattice (e.g., symmetry, the size, the depth, and periodicity). As such, the method should be useful for preparing sensors based on hybrid-LSPR with controlled coupling between AuNPs and SLR modes.<br/><br/>1. Matricardi, C.; Hanske, C.; Garcia-Pomar, J. L.; Langer, J.; Mihi, A.; Liz-Marzán, L. M., Gold Nanoparticle Plasmonic Superlattices as Surface-Enhanced Raman Spectroscopy Substrates. <i>ACS Nano </i><b>2018,</b> <i>12</i> (8), 8531-8539.<br/>2. Halas, N. J.; Lal, S.; Chang, W.-S.; Link, S.; Nordlander, P., Plasmons in Strongly Coupled Metallic Nanostructures. <i>Chemical Reviews </i><b>2011,</b> <i>111</i> (6), 3913-3961.<br/>3. Cherqui, C.; Bourgeois, M. R.; Wang, D.; Schatz, G. C., Plasmonic Surface Lattice Resonances: Theory and Computation. <i>Accounts of Chemical Research </i><b>2019,</b> <i>52</i> (9), 2548-2558.<br/>4. Kravets, V. G.; Kabashin, A. V.; Barnes, W. L.; Grigorenko, A. N., Plasmonic surface lattice resonances: a review of properties and applications. <i>Chemical reviews </i><b>2018,</b> <i>118</i> (12), 5912-5951.