I have been trying to make an even PEDOT: PSS (PH1000) film with the doctor blade technique (tape casting) with varying results. I have been using a silicon substrate that's treated with piranha solution (H2SO4:H2O2::2:1 by volume) to make the surface hydrophilic. I know I might be able to improve my results by adding DMSO or EG. But I was wondering if there were other methods without the use of additives.
@Aditya Saha, you are right that controlling the high quality of PEDOT coatings is always a challenge. you could try to use one of alcohol solvents mixing with your PEDOT:PSS to increase the hydrophilic properties on the surface of your substrates. And heating substrates is also help as well.
Xuhua Wang, Thank you for your answer. What solvents would you recommend?
hi Aditya,
in addition to the previous answers you can check the publication of L. Wengeler et al. "
Comparison of large scale coating techniques for organic and hybrid films in polymer based solar cells"
There you see the dependency of the coating thickness from the gap width and the coating speed (in this case not for PEDOT:PSS; but you could gain some learnings from this publication I think). If the speed is high enough you could estimate your wet film thickness to be half of the gap width of your doctor blade.
Regards,
Sebastian
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