I synthesize silver nanoparticles using polyvinyl alcohol and silver nitrate with varying concentrations of silver nitrate which is 0,1%, 0,2%, and 0,3% at 90 degrees. I have got the characterization result, when I increase the concentration of silver nitrate from 0.1% to 0.3%, the crystallite size decreases and also the particle size, and the band gap decreases. Is it possible the particle size decreases when the concentration precursor increases ? I would like to know the reason for this case.
Yes, because the higher the concentration at the start, the more initial particles that will form.
Dear all, this is the normal behavior, but both decrease and increase are practically noticed since other factors also have their own specific influence such as the surfactant concentration. My Regards
https://doi.org/10.1039/C7CE01406F
A similar thread:
https://www.researchgate.net/post/Does-by-increasing-the-concentration-of-precursor-as-compared-to-reducing-agent-wavelength-and-absorption-peak-of-nanoparticles-decrease
During the formation of nanoparticles, there can be generally 2 steps: nucleation and growth. If the concentration of the ion precursors is high, nucleation might increase so that there are many more NP nuclei seeds and less remaining ion precursors for the subsequent growth process. Therefore, higher number of smaller NPs might be obtained.
Article Mechanisms of Nucleation and Growth of Nanoparticles in Solution
Hi,
The process of forming nanoparticles in solution is very complex. Indeed, it can be divided into several stages.. First of all, the metal precursor is reduced to metal: the metal atoms, generally insoluble, will aggregate into small clusters, embryos. More and more metal atoms are present in the medium, and as soon as an embryo grows sufficiently and reaches a certain size called “critical size”, it precipitates in the form of a solid particle: This is the nucleation stage, which is followed by the growth of this nuclei. The primary particle, whose size is of the order of a nanometer, is obtained. This state is not stable and the particles will continue to grow thanks to two mechanisms:
# In the first one, the growth can continue with the addition of the metal that has just been reduced on the primary particle. A priori, this mechanism is governed by diffusion. It is therefore slow and leads in principle to particle sizes smaller than a micron.
# In the second mechanism, the primary particles can aggregate rapidly to form larger clusters. This mechanism allows a faster size increase and the resulting particles can reach sizes larger than a micron.
Of course, nothing prevents the two mechanisms from coexisting.
With my best regards
Hi,
For more details, please see the attached paper
With my best regards
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