ИСТИНА

Nanooptics is an emerging field in nanotechnology, which combines nanosized objects and unique light-matter interaction properties at nanoscale. One of the most promising nanoobjects suitable for nanooptics are metal nanoparticles (NPs), which possess Localized Surface Plasmon Resonance (LSPR). And the most attractive strategy, which can bring a significant shift in the area of optics production (especially for filtering and mirroring applications), is based on large-scale self-assembly of metallic NPs with tunable optical response on various substrates[1] and interfaces.[2] Recently we have developed a novel, scalable and simple method to obtain highly stable continuous gold nanoparticle (AuNPs) films at various liquid|liquid interfaces (LLIs).[3] Formation of such nanofilms requires only vigorous shaking of aqueous phase containing AuNPs with organic phase containing tetrathiafulvalene species. The method allows creating both sub- and multilayer self-healing films (Fig.1A). In this work we investigate optical responses – both extinction and reflection – of nanofilms in situ with stepwise increasing of AuNPs concentration. Obtained results are intriguing and indicate non-linear behavior of assemblies with accumulating AuNPs. We propose that this effect is caused by morphological changes occurred in the film settled at LLI: 2D closed-packed films transfers into 3D thick layer. It may be utilized for further development of liquid filters and mirrors. Figure 1: A) Stepwise increasing of AuNP coverage at w|DCE (1, 2, 4, 6, 8 and 35 ml of 38 nm AuNP solution). B) Corresponding optical responses to stepwise increasing of AuNPs concentration at w|DCE interface: UV-Vis-IR spectra and photos demonstrating filtering and mirroring applications. References: [1] Z. A. Khan et al., J. Mater. Sci., DOI: 10.1007/s10853-011-5651-0 [2] E. F. Borra et al., Nature, DOI : 10.1038/nature05909 [3] E.Smirnov et al., ACSNano, DOI: 10.1021/nn503644v