I am working on liquid phase exfoliation of Graphene and black phosphorous using NMP. But in transferring the exfoliated flakes i am getting difficulties. I have tried spin coater previously. All flakes get merge on the corner. I am using drop casting at a temp of 180C. But I'm not getting good results. Most of flakes I am getting on the corners. In the middle part of substrate there are many fine thickness flakes but with higher amount of residue. I have tried dilution as well but it doesn't work.

Please let me know if anyone has suggestion.

Thanking you in anticipation.