Hi Arpan,

In my opinion spin coating can give a better and easier to have a uniform coating thickness that can effect the photocatalytic activity. However you need to consider the medium used and the density of the catalyst that used. Good smooth surface also can be produced if using for coating application.

Hello, I would like to share my experience and I hope this helps. I spin coated ZnO nanoparticles (dispersed in ethanol) on hydrophilic polymer and most of the particles migrated towards the edge of the substrate (I tried with different rpm). I also observed that the distance between nanoparticles in the central region was more compared to dip coating. While in dip coating, I did not face a problem of nanoparticles migrating towards the edges, with a drawback that the coating was thicker towards the bottom of the substrate (due to obvious reasons of gravity). I obtained better coating in terms of number of nanoparticles per square cm in dip coating and it was easier to reproduce the results unlike spin coating (probably due to the manual error in dispensing the drops in spin coating). The last thing is to disperse your particles really well so that they do not aggregate and spread uniformly on the substrate. Good luck with the trials!