I am currently biosynthesizing silver nanoparticles using ethanolic leaf extract. Upon addition of the leaf extract to 1mM silver nitrate, the solution turns brown in color after exposure to sunlight for 30 minutes. Upon checking the SPR using UV-vis spectroscope, the absorbance reading peaks between 200-250 nm then decreases gradually until 600 nm. No increase in absorbance was seen between 400-500 nm. Your help will be highly appreciated. Thank you!
Dear Allan Espiritu
I agree with colleagues above that you must run your reaction to insure the formation nano silver particles in the intended range to achieve the absorption at the wavelength you intend. So, you have to verify the formation of nano sized silver grains.
Best wishes
no absorption in the 400-600 nm lambda range means no silver nanoparticles smaller than 10^2 nm size range. A possibility is that you have produced larger (even if sub-micron) particles and the brownish color stems from diffuse reflectance. You should check the presence an shape/size of any possible Ag particulate with TEM or FESEM (the former being the best choice, if available))
I think u need to do adding silver nitrate to leaf extract in darkroom with less light. Make atleast 5 concentration 1:9 to 9:1.
Colour get oxidised after keeping longtime in light.
Dear Allan Espiritu
I agree with colleagues above that you must run your reaction to insure the formation nano silver particles in the intended range to achieve the absorption at the wavelength you intend. So, you have to verify the formation of nano sized silver grains.
Best wishes
We think it is not silver nanoparticle as it is not showing any peak in its standard range.
Kindly check the particle size.
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