Binary plasmonic honeycomb structures: High-resolution EDX mapping and optical properties

- Preparation of binary, plasmonic honeycomb lattice by interface-mediated, colloidal self-assembly.
- Positional mapping of gold and silver particles in honeycomb lattice by high-resolution EDX analysis.
- Plasmon resonance coupling in honeycomb structure evidenced by far-field extinction spectroscopy.

Surface coatings with plasmonic nanostructures find applications in a broad range of fields such as sensing, lasing and optoelectronic devices. Structural control is as important as a high resolution structural analysis of these structures for their actual use in relevant applications and the elucidation of structure-property relations. Here we demonstrate the preparation of binary plasmonic honeycomb structures by the sequential double self-assembly of two hexagonally packed monolayers onto the same solid support. Each monolayer consists of noble metal-hydrogel core-shell particles with either gold or silver cores. The honeycomb lattice shows a high degree of order as evidenced by different microscopic techniques and FFT investigation of the positional maps. The plasmonic properties are investigated by UV-vis extinction spectroscopy pointing to plasmon resonance coupling between the different metal cores. High-resolution elemental mapping by EDX is used to unravel the position of the different metal cores with submicron resolution.

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