The theory of nanoparticle condensation is very complex. Its path: formation of molecules, nuclei condensation, nanoparticles. At each stage, interaction with particles is possible. Where your additives begin to interact with the surface of the particles is unknown. Therefore, your problem with many unknowns is not grateful. They do not take it. You have achieved good results in size and it is better to focus on the practical application of your nanoparticles. To get acquainted with the mechanism, you can look at the article on the example of obtaining gold nanoparticles.
Article Kinetics and mechanism of the interaction between HAuCl4 and rutin