Predicting the Size of Silver Nanoparticles from Their Optical Properties

In this study, localized surface plasmon resonance (LSPR) of the spherical silver nanoparticles (AgNPs) was evaluated based on experimental and theoretical viewpoints. In the experimental phase, a facile seed-mediated method was employed to synthesize spherical AgNPs with different sizes. As expected, an increase in the size of AgNPs resulted in a red-shift in LSPR peak position from 390 to 460 nm. Besides, the theoretical LSPR peak position of AgNPs was derived from Mie theory using different refractive indices databases. A comparison between the experimentally obtained data and the theoretical predictions indicated that Palik database can lead to a more reliable data regarding the size of AgNPs. Finally, a relation was established for the prediction and estimation of AgNPs' size through a simple measurement of LSPR position with a UV-Vis spectrometer.