UV-Vis Absorbance Spectra (graph) of Silver Nanoparticles
Important Things While Analysing Siver Nanoparticles UV-Vis Absorbance Graph
UV-Vis spectroscopy can be used for the elemental analysis of silver nanoparticles in almost every polar/nonpolar solvents. The absorption peak maxima (lamda-max) of silver nanoparticles is mostly observed around 420 nanometer wavelength of electromagnetic spectra. Peak maxima (lamda-max) of silver nanoparticles can also get some red (toward higher wavelength) or blue (toward lower wavelength) shift depending on the particle size. The lamda max value of silver nanoparticles mostly fall from 400 nanometer to 440 nanometers of EM spectra. Lamda-max can also be used as a powerful tool for particle size estimation (not exact) of the silver nanoparticles. Bigger silver nanoparticles are having red shift (higher absorption wavelength) while smaller nanoparticles are having blue shift (lower absorption wavelength). Lamda-max shift is also possible by the functionalities (for example, organic functionalities like carboxyl, hydroxyl & amine etc. or even by doping and composites with some other elements, molecules or polymers) in silver nanoparticles. So the size of silver nanoparticles is having specific lamda-max, which is already effected by the functionalities or chemicals involved in the experiment.
You can always make your own calibration graph for the determination of size from lamda-max in your own experimentation conditions, which can help you to determine the size of unknown sample with the same experiment conditions used while making the calibration graph.