Combining high mobility graphene transistors with efficient light-absorbing graphene quantum dots produces highly sensitive photodetectors with wide spectral response. However, an inherent difficulty in fabricating such devices is the wettability of the hydrophilic graphene quantum dots onto the hydrophobic graphene transistor array. We describe a smooth, uniform coating of a graphene quantum dot layer by adding a non-ionic fluorosurfactant: Capstone FS-30. It reduces the surface tension of hydrophilic graphene quantum dots on the hydrophobic substrate, sufficiently improving the wetting property.