Study of the formation of silver nanoparticles and silver nanoplates by chemical reduction method

The control of the diameter of silver nanoparticles, as well as the size and shape of silver nanoplates, is crucial for a lot of applications, from antibacterial solutions or surface treatment to biosensors. We synthesised silver nanoparticles and silver nanoplates from silver nitrate through a simple chemical reduction method in ambient conditions. Polyvinyl pyrrolidone (PVP) is used as both size controller and capping agent, while hydrogen peroxide and trisodium citrate (TSC) are used to control the nanoplates synthesis. Different solvents are used for obtaining the nanoparticles, i.e., water, ethylene glycol and ethanol. Standard characterisation was made by ultraviolet–visible spectrophotometry and transmission electron microscopy (TEM). The spherical nanoparticles solution presents a yellow colour, indicating the sole presence of Ag nanoparticles within a narrow diameter range as confirmed by the surface plasmon resonance peak which between 399 nm and 418 nm depends on the solvent. For the silver nanoplates, the colour of solutions varies from green, blue, violet, to purple when modifiers are added to the silver nanoparticle synthesis solution. We present the influence of the concentration of the different reagents on the size and shape of these nanostructures.