Solution Processed, Versatile Multilayered Structures for the Generation of Metal-Enhanced Fluorescence

We present an all-solution processed multilayered structure completely obtained via spin-coating, which can be used to study and optimize the phenomenon of metal-enhanced fluorescence. Indeed, the electromagnetic interactions occurring between fluorescent probes and localized surface plasmons typical of metal nanoparticles (NPs), which influence the fluorescence quantum yield, are strongly dependent on the nanoparticle/molecule distance. The platform proposed here offers unique advantages in terms of processability, allowing a fine-tuning of such a distance in a single deposition step. Fluorescence versus fluorophore/AuNP spacing curves are shown for two organic systems, namely, a perylene-based dye dispersed in a polymer matrix and a polyconjugated polymer (poly­(3-hexyl­thio­phene)), interacting with a nanostructured gold thin film. In both cases, optimal distances and enhancement factors have been measured

Designing Optoelectronic Properties by On-Surface Synthesis: Formation and Electronic Structure of an Iron–Terpyridine Macromolecular Complex

Supramolecular chemistry protocols applied on surfaces offer compelling avenues for atomic-scale control over organic–inorganic interface structures. In this approach, adsorbate–surface interactions and two-dimensional confinement can lead to morphologies and properties that differ dramatically from those achieved via conventional synthetic approaches. Here, we describe the bottom-up, on-surface synthesis of one-dimensional coordination nanostructures based on an iron (Fe)-terpyridine (tpy) interaction borrowed from functional metal–organic complexes used in photovoltaic and catalytic applications. Thermally activated diffusion of sequentially deposited ligands and metal atoms and intraligand conformational changes lead to Fe–tpy coordination and formation of these nanochains. We used low-temperature scanning tunneling microscopy and density functional theory to elucidate the atomic-scale morphology of the system, suggesting a linear tri-Fe linkage between facing, coplanar tpy groups. Scanning tunneling spectroscopy reveals the highest occupied orbitals, with dominant contributions from states located at the Fe node, and ligand states that mostly contribute to the lowest unoccupied orbitals. This electronic structure yields potential for hosting photoinduced metal-to-ligand charge transfer in the visible/near-infrared. The formation of this unusual tpy/tri-Fe/tpy coordination motif has not been observed for wet chemistry synthetic methods and is mediated by the bottom-up on-surface approach used here, offering pathways to engineer the optoelectronic properties and reactivity of metal–organic nanostructures