Preparation of 2D Periodic Nanopatterned Arrays through Vertical Vibration-Assisted Convective Deposition for Application in Metal-Enhanced Fluorescence

The performance of a metal-enhanced fluorescence (MEF) substrate is fundamentally based on the orientation of the metal nanostructures on a solid substrate. In particular, two-dimensional (2D) periodic metallic nanostructures exhibit a strong confinement of the electric field between adjacent nanopatterns due to localized surface plasmon resonance (LSPR), leading to stronger fluorescence intensity enhancement. The use of vertical vibration-assisted convective deposition, a novel, simple, and highly cost-effective technique for preparing the 2D periodic nanostructure of colloidal particles with high uniformity, was therefore proposed in this work. The influences of vertical vibration amplitude and frequency on the structure of thin colloidal film, especially its uniformity, monolayer, and hexagonal close-packed (HCP) arrangement, were also investigated. It was found that the vibration amplitude affected film uniformity, whereas the vibration frequency promoted the colloidal particles to align themselves into defect-free HCP nanostructures. Furthermore, the results showed that the self-assembled 2D periodic arrays of monodisperse colloidal particles were employed as an excellent template for a Au thin-film coating in order to fabricate an efficient MEF substrate. The developed MEF substrate provided a strong plasmonic fluorescence enhancement, with a detection limit for rhodamine 6G as low as 10(-9) M. This novel approach could be advantageous in further applications in the area of plasmonic sensing platforms.

Automated summary

This study proposed a novel vertical vibration-assisted convective deposition technique for preparing high uniformity, two-dimensional periodic nanostructures of colloidal particles. The influences of vibration amplitude and frequency on the structure of thin colloidal film were investigated. The results showed that vibration amplitude affected film uniformity, while vibration frequency promoted the formation of defect-free hexagonal close-packed nanostructures. Additionally, the self-assembled colloidal particle arrays were employed as a template for fabricating efficient metal-enhanced fluorescence substrates. This method holds great potential for plasmonic sensing platforms.