Solvent effects on the localized surface plasmon resonance of Ag nanoparticles

Abstract

Ag, Au, and Cu are common metals which exhibit strong optical adsorption in the visible region. Notably, Ag has demonstrated the most effective light-driven chemical reactions. The characteristics of the solution play a direct role in influencing the localized surface plasmon resonance (LSPR) and stability of Ag nanoparticles (AgNPs) in various applications, thereby regulating the efficiency of the reaction. Nevertheless, to date, there has been a lack of systematic research on the impacts of solvents on the surface plasmon resonance of AgNPs. Here AgNPs were synthesized using sodium citrate as a reducing agent and the effect of the solvent on the excitation energy at the surface interface to the LSPR was investigated. The determination was made that the surface plasmon band of AgNPs is significantly impacted by the characteristics of the solvent including pH, polarity, and the lengths of alcohol chains. The influence of ethanol was most pronounced with alcohol, while in polar solvents, the level of polarity in the solvent correlated with the magnitude of the LSPR effect on AgNPs. The effects of solvents on the LSPR of AgNPs also determine that water is a suitable solvent for storage. The results are valuable information for improving the activity and sensitivity of the LSPR in plasmonic applications.