Quantitative Surface-Enhanced Raman Spectroscopy Analysis through 3D Superlattice Arrays of Au Nanoframes with Attomolar Detection.

This paper reports a methodology for synthesizing and ordering gold nanoframes into three-dimensional (3D) arrays with a controlled thickness, leading to homogeneous plasmonic superstructures, with which quantitative analysis via surface-enhanced Raman spectroscopy (SERS) has been successfully demonstrated. Because this preparation method allows for systematic control of nanoframe film thickness and the resulting 3D plasmonic superstructure, which exhibits a unique nanoporous network of hot-spots, detection limits down to 10-18 M, corresponding to ≈6000 molecules, have been measured. Compared to analogous solid nanoparticle superstructures, the nanoframe superstructures with their unique nanoporous architecture effectively dissipate the heat inevitably generated by laser excitation during measurement, effectively suppressing the formation of carbonaceous materials and therefore their accompanying fluorescence interference, especially important for low concentration detection.