Two-Dimensional Plasmonic Superlattice Based on Au Nanoparticles Self-Assembling onto a Functionalized Substrate

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• 作者：Michela Corricelli ; Nicoletta Depalo ; Elisabetta Fanizza ; Davide Altamura ; Cinzia Giannini ; Dritan Siliqi ; Rosa Di Mundo ; Fabio Palumbo ; Vasily G. Kravets ; Alexander N. Grigorenko ; Angela Agostiano ; Marinella Striccoli ; M. Lucia Curri
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：April 10, 2014
• 年：2014
• 卷：118
• 期：14
• 页码：7579-7590
• 全文大小：624K
• 年卷期：v.118,no.14(April 10, 2014)
• ISSN：1932-7455

文摘

Au nanoparticles (NPs) self-assembled by means of a simple solvent evaporation strategy in a two-dimensional (2D) superlattice with a highly controlled geometry and extending over micrometers squared when drop cast onto a suitably functionalized silicon substrate. The assembly procedure was defined by carefully monitoring experimental parameters, namely, dispersing solvent, deposition temperature, Au NP concentration, and chemistry of supporting substrate. The investigated parameters were demonstrated to play a significant role on the delicate energetic balance of the mutual NPs as well as NP鈥搒ubstrate interactions, ultimately directing the NP assembly. Remarkably, substrate surface chemistry revealed to be decisive to control the extent of the organization. Scanning electron microscopy demonstrated that the 2D superlattice extends uniformly over hundreds of square micrometers. Grazing-incidence small-angle X-ray scattering investigation validated the Au NP organization in crystalline domains and confirmed the role played by the surface chemistry of the substrate onto the 2D lattice assembly. Finally, preliminary spectroscopic ellipsometry investigation allowed extraction of optical constants of NP assemblies. The localized surface plasmon resonance modes of the NP assemblies were studied through a combined analysis of reflection, transmission, and ellipsometric data that demonstrated that the plasmonic properties of the Au NP assemblies strongly depend on the substrate, which was found to influence NP ordering and near-field interactions between NPs.