Direct Nucleation of Hierarchical Nanostructures on Plasmonic Fiber Optics Enables Enhanced SERS Performance

Di Zheng; Riccardo Scarfiello; Muhammad Fayyaz Kashif; Liam Collard; Linda Piscopo; Maria Samuela Andriani; Elisabetta Perrone; Concetta Nobile; Massimo De Vittorio; Ferruccio Pisanello; Luigi Carbone

arXiv · 2503.11534

Direct Nucleation of Hierarchical Nanostructures on Plasmonic Fiber Optics Enables Enhanced SERS Performance

Di Zheng·Riccardo Scarfiello·Muhammad Fayyaz Kashif·Liam Collard·Linda Piscopo·Maria Samuela Andriani·Elisabetta Perrone·Concetta Nobile·Massimo De Vittorio·Ferruccio Pisanello·Luigi Carbone

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Abstract

We present an innovative fabrication method to achieve bottom-up in situ surface-overstructured Au nanoislands (NIs) with tunable grades of surface coverage, elongation, and branching, directly on micro-optical fibers for sensing applications. These all-in-gold hierarchical nanostructures consist of NIs coated with surface protrusions of various morphologies. They are created in solution using a selective seeded growth approach, whereby additional gold growth is achieved over Au NIs formerly developed on the fiber facet by a solid-state dewetting approach. The morphology of nanosized surface-NI overstructuring can be adjusted from multi-dot-decorated Au NIs to multi-arm-decorated Au NIs. This engineering of optical fibers allows for improved remote surface-enhanced Raman spectroscopy (SERS) molecular detection. By combining solid-state dewetting and wet-chemical approaches, we achieve stable in-contact deposition of surface-overstructured NIs with the optical fiber solid substrate, alongside precise control over branching morphology and anisotropy extent. The fiber optic probes engineered by surface-overstructured NIs exhibit outstanding sensing performance in an instant and through-fiber detection scheme, achieving a remarkable detection limit at 10-7 M for the R6G aqueous solution. These engineered probes demonstrate an improved detection limit by one order of magnitude and enhanced peak prominence compared to devices solely decorated with pristine NIs.

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Di Zheng, Riccardo Scarfiello, Muhammad Fayyaz Kashif, Liam Collard, Linda Piscopo, Maria Samuela Andriani, Elisabetta Perrone, Concetta Nobile, Massimo De Vittorio, Ferruccio Pisanello, Luigi Carbone. 2025-03-14. Direct Nucleation of Hierarchical Nanostructures on Plasmonic Fiber Optics Enables Enhanced SERS Performance. https://arxiv.org/abs/2503.11534

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