Unleashing the potential of magnesium nanoparticles: A green synthesis for sustainable sensing solutions

Abstract

For the first time, we unveil an innovative, one-step approach for synthesizing magnesium nanoparticles (MgNPs), combining efficiency, simplicity, and environmental sustainability. Our method utilizes spin-coating of a magnesium precursor-loaded poly(methyl methacrylate) (PMMA) dispersion onto n-doped silicon substrates. This process induces vapor-driven phase separation, leading to the self-assembly of PMMA into a nanoporous film that encapsulates MgNPs within its nanoholes. Unlike traditional methods that depend on toxic reducing agents or complex synthesis routes, our approach eliminates the need for additional stabilizers, making it a greener and more efficient alternative for nanostructure fabrication. By systematically optimizing precursor concentration and spin-coating speed, we precisely control the size and dispersity of MgNPs, achieving spherical nanoparticles of approximately 50 nm − the smallest size reported to date. Optical characterization using micro-extinction spectroscopy confirms the presence of localized surface plasmon resonance (LSPR) in the Mg/PMMA composite, demonstrating its potential for advanced sensing applications. X-ray photoelectron spectroscopy (XPS) reveals that MgNPs are passivated by a native MgO layer, enhancing stability and minimizing oxidation under ambient conditions. These substrates exhibit outstanding surface-enhanced Raman scattering (SERS) sensitivity, detecting 4,4′-bipyridine (4,4′-BP) at low concentrations. This innovative strategy offers a sustainable path for developing earth abundant plasmonic nanomaterials with tunable optical properties.