I work with bismuth nanoparticles, and would like to run DLS (Dynamic Light Scattering) on them to determine size. But they aggregate very quickly, despite their surface coating (oleylamine) being very soluble in the solvent (THF or hexane). They stay in solution but their size measurements are far too large, which I can confirm with TEM. Any suggestions?
if u get larger particle size in DLS, sure in TEM also particle size will be larger only, i think homogenization might improper otherwise stabilizers doesn't work properly....
Arjun: Yeah I think stabilizers are the best option. I've tried a few like SDS and other ampiphillic molecules. I'll probably try a few more. Thanks!
The DLS data usually can not confirm with your TEM result because it provide hrdrodiameter and TEM provide particle size. If you eager to do it, I suggest you using NOBF4 to remove the surface coating, which may be help. Besides, PEGylate was also suggested to obtain better solubility.
That's true, Yuxin, but my particles are showing up as 2 or 3 times their size. I think aggregation is a bigger problem than hydrodynamic differences. But you are right that I could make the particles more soluble by wrapping them in PEG and trying DLS that way. It's another good option.
It seems that the surface charge of your particles is too low due to the coating and this might cause the aggregation. I agree with Liu and I suggest you to reduce the concentration and sonicate your samples before measurement.
Dear Hayden
Low precursor concentration or higher stabilizer concentration or both options simultaneously will help you to prevent aggregation.
Best regards
Muhammad imran khattak