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Articolo in rivista, 2023, ENG, 10.3390/coatings13040797

A Study of the Laser-Assisted Alloying Effect on Plasmonic Properties of Au-Pd Nanostructured Film Using Surface-Enhanced Raman Spectroscopy

Chawki Awada; Francesco Ruffino

Department of Physics, College of Science, King Faisal University, P.O. Box 400, Al-Ahsa 31982, Saudi Arabia 2 Dipartimento di Fisica e Astronomia "Ettore Majorana", Università di Catania and CNR-IMM, Catania (University) Unit, 95123 Catania, Italy * Authors to whom correspondence should be addressed.

In this work, we report a study on the effect of the laser-assisted alloying effect on plasmonic properties of Pd and Au-Pd nanostructures using surface-enhanced Raman spectroscopy (SERS). The monometallic and bimetallic nanostructures are formed by nanosecond-laser induced de-wetting and the alloying of pure Pd and bimetallic Au-Pd nanoscale-thick films deposited on a transparent and conductive substrate. The morphological characteristics of the nanostructures were changed by controlling the laser fluence. Then, 4-nitrithiophenol (4-NTP) was used as an adsorbed molecule on the surface of the nanostructures to analyze the resulting SERS properties. A quantitative analysis was reported using the SERS profile properties, such as FWHM, amplitude, and Raman peak position variation. An excellent correlation between the variation of SERS properties and the nanostructures' size was confirmed. The optical enhancement factor was estimated for Pd and Au-Pd nanostructures for the laser fluence (0, 0.5, 0.75, 1, and 1.5 J/cm2).

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