Dear all,
everyone knows that metal nanoparticles (size 5 - 50nm) are not stable in their size between 5 - 100 nm, especially at high temperatures.
What are the interaction forces between these nanoparticles that can be done?
How the annealing temperature has an effect on metal NPs size?
Thanks for your help.
NPs have much better crystallization after annealing, that is the main reason why the size changea when the temperature is high, what does not usually happens at room temperature.
Regards,
Lack of stability, high reactivity or catalytic properties are common for all sub-50 nm nanoparticles, whether they are metallic or not, due to high surface to volume ratio, and thereby large surface energy. In sub-20 nm regime quantum confinement of electronic states as well as phonons introduce some new features, which especially get pronounced for quantum dots, where all three dimensions suspend (giving rise to 0D nanoparticles). For most metallic nanoparticles, plasmonic interactions add up to this. Besides, electronic properties may vary depending on the electron affinity and ionization potential of the metals as a function of size.
In high temperature annealing, crystal defects minimize, which promotes larger crystal growth and continuity of grains (and sometimes agglomeration also). For better crystallinity annealing is always suggested, unless some possibility of phase transition is associated.
Oh yes, I completely kipped the nanoparticle's crystallization.
Thank you very much for your time.
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