Synthesis of Garlic-Stabilised AgNPs and Their Potential Application in Memory Devices

In this study, we report the synthesis of silver nanoparticles (AgNPs) using different crude garlic aqueous extracts as stabilising agents and sodium borohydride as reducing agent. The crude garlic extract was obtained using the cold (maceration) and hydro-distillation extraction methods. The synthesised AgNPs and garlic-stabilised AgNPs (G-AgNPs) were characterised using various techniques. The formation of a surface plasmon resonance peak at 393 nm from the ultraviolet–visible (UV–Vis) spectroscopy indicates the synthesis of AgNPs. The fluorescence intensity displayed upon stabilisation with garlic extract depicts the passivation provided by the crude extracts. However, the fluorescence study showed that the hydrosol-stabilised AgNPs gave a higher emission intensity than the cold extract-stabilised ones. Variations in the concentration of hydrosol extract, AgNO₃ and NaBH₄ solutions showed that the fluorescence intensity of synthesised garlic-AgNPs was more enhanced at 0.063 g/ml of hydrosol, 0.3125 mM of AgNO₃ and 2.5 mM of NaBH₄ solution. The scanning electron microscope (SEM) results indicate the formation of spherically shaped NPs, whereas the result obtained from the transmission electron microscope (TEM) shows the formation of larger sizes of garlic-stabilised AgNPs compared to unstabilised AgNPs. The X-ray diffraction spectroscopy (XRD) result reveals lesser crystallinity for G-AgNPs than for AgNPs without garlic as a stabilising agent. The resistivity switching behaviour of optimised garlic-stabilised AgNPs with Cu and ITO electrodes exhibited remarkably similar I-V characteristics compared to uncoated AgNPs. This shows the potential use of garlic-stabilised AgNPs in memory devices.