Empowering Electroless Plating to Produce Silver Nanoparticle Films for DNA Biosensing Using Localized Surface Plasmon Resonance Spectroscopy

To facilitate the implementation of biosensors based on the localized surface plasmon resonance (LSPR) of metal nanostructures, there is a great need for cost-efficient, flexible, and tunable methods for producing plasmonic coatings. Due to its simplicity and excellent conformity, electroless plating (EP) is well suited for this task. However, it is traditionally optimized to produce continuous metal films, which cannot be employed in LSPR sensors. Here, we outline the development of an EP strategy for depositing island-like silver nanoparticle (NP) films on glass with distinct LSPR bands. The fully wet-chemical process only employs standard chemicals and proceeds within minutes at room temperature. The key step for producing spread-out NP films is an accelerated ripening of the silver seed layer in diluted hydrochloric acid, which reduces the nucleation density during plating. The reaction kinetics and mechanisms are investigated with scanning (transmission) electron microscopy (SEM/STEM), X-ray photoele...