Dear Sir. Concerning your issue about how to measure particle size using UV- Vis spectroscopy . This technique of measurement includes comparison between UV-Vis spectra fitting of the colloidal nanoparticles and theoretical calculation of absorption spectra. For metal colloidal nanoparticles, Mie theory is used to obtain the Lorentzian profile of absorption. It is shown that the width of this profile is related to the size of nanoparticles. The intensity of absorption spectra is related to the liquid dielectric constant and real part of interband transition of metal nanoparticles. This allows us to measure the size of colloidal Ag nanoparticlesor other particles in distilled water. I think the following below links and the attached file may help you in your analysis:

Thanks

Thankyou sir will look into it. but i dont see any links actually

Hello Deepa,

I think, the following discussion could be helpful to you

https://www.researchgate.net/post/Is_there_any_way_to_find_particle_size_of_polymeric_nanoparticles_by_using_uv-vis_spectroscopy

regards

raeesh

Please, consider that the UV-Vis peak represents the average size of particles. It is better to know the size distribution: the number of particles with the corresponding size. For this goal, people use first electron microscopy (scanning or transmission depending on particle size) or/and X-ray small angle scattering which gives volume particle distribution.

You can calculate the size from XRD. very good explanation is here on this link,

http://www.instanano.com/characterization/theoretical/xrd-size-calculation/

You cannot calculate sizes from XRD. The best it is possible only to estimate something average using X-ray diffraction. Not all particles are diffracting, quite often some part of the particle is diffracting and some part is not in a diffraction position (twins). In order to verify all estimation you have to come again to electron microscopy.

@Elena Ma'am Electron Microscopy is the best technique for size determination but instead of determination of size from UV, I suggested XRD

here you can find the equation

https://www2.chemistry.msu.edu/courses/cem434/ac0702084_UVVis_CS.pdf

I'm not familiar with the effective mass approximation term, but you might find these two publications interesting:

Effect of the Solvent on the Size of Clay Nanoparticles in Solution as Determined Using an Ultraviolet-Visible (UV-Vis) Spectroscopy Methodology

March 2015

Applied Spectroscopy 69(6):671

DOI: 10.1366/14-07704

In situ characterization of organo-modified and unmodified montmorillonite aqueous suspensions by UV-visible spectroscopy

June 2015

Journal of Colloid and Interface Science 456

DOI: 10.1016/j.jcis.2015.06.011

https://www.azonano.com/article.aspx?ArticleID=3588

Deepa Eswara sarma Nanoparticles are ultrafine particles in the size of nanometer, which are generally in the range 1 to 100 nm: however, less than the submicron particles. All the solid particles consist of the atoms or the molecules. As they are micronized, they tend to be affected by the behavior of atoms or the molecules themselves and to show different properties from those of the bulk solid of the same material. It is attributable to the change of the bonding state of the atoms or the molecules constructing the particles.

Micronization of solid particles lead to an increase in the surface area compared to the particle size, which causes dramatic changes in structural and optical properties. The unique features of nanoparticles depend critically on their size, shape, and morphology.

The optical properties of metallic nanostructures are determined by the collective resonant oscillations of their conduction electrons with respect to the positive ion background, known as plasmon which relates the extinction coefficients to the size and geometrical properties of metallic nanostructures. Therefore, optical spectroscopy is one of the simplest and easiest ways to determine the geometrical properties of metal nanostructures including their size and shape.

One of the unique features of metal nanoparticles is the surface plasmon resonance, which is exploited in optical spectroscopy to estimate the size and distribution of these nanoparticles.

In literature, there are many ways to estimate the size of nanoparticles from their absorbance data. Some of the equations are theoretically derived, while some are the merger of theoretical equations and experimental data fitting. I prefer to calculate it with the Haiss equation.

d=ln((λSPR-λ0)/L1)/L2

where

λSPR is the wavelength at which maximum absorption occurs

λ0 is the wavelength at which minimum absorption occurs at the start of SPR

while, as mentioned earlier, L1 and L2 are the values taken from the data fit of TEM vs UV-Vis, whose values are L1=6.53 and L2=0.0216

In the following video, I have explained all the above discussions in detail. Links to the files used in the Origin tutorial video have been provided in the video description. A worked example is presented here in this video. Thanks

https://youtu.be/ktX9ehEvXWQ

Can we apply this for only metal nanoparticles or for semiconductor as well?

Bishal Hamal For metal oxide-based semiconductors, the UV-Vis spectroscopy technique can still provide valuable information about their optical properties, such as bandgap energy and absorption characteristics. However, estimating the particle size solely based on SPR analysis may not be suitable in this case.