Importance of Gold Nanorods’ Aggregation in Surface Plasmon Coupling with a Photochromic Film in Hybrid Structures

Abstract

In this paper, hybrid samples composed of photochromic film deposited on glass substrates functionalized with gold nanorods were synthesized. Three samples of gold nanorods with different aspect ratios were produced and characterized by electron microscopy and extinction spectroscopy. The rod populations were chosen to have more or less overlap between the two surface plasmon resonance bands and the absorption band of the colored form of the photochromic compounds which is commercially available. Deposition of the nanoparticles on glass substrate exhibits a new surface plasmon resonance coupling band coming from their side-by-side organization. Spectroscopic studies of the photoisomerization process of photochromic film spin-coated on the gold nanorods show reversible interaction between photochromism and plasmonic properties. Despite such coupling has been previously reported emphasizing the main role of the bands overlapping, in this paper, we clearly show that the surface resonance coupling band is the key parameter to monitor the photochromic process. This result emphasizes the importance of coupling nanoparticles to increase their sensing potential and interaction with photochromic molecules.

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“…4C and D). Such findings, indicate a good particle stability since the particles aggregation can induce changes in the absorption spectra of the nanorods and consequently affect their PTT capacity [69,70].…”