Methods, apparatus, and systems for fabricating solution-based conductive 2d and 3d electronic circuits

Abstract

This work develops a novel microfluidic method to fabricate conductive graphene-based 3D micro-electronic circuits on any solid substrate including, Teflon, Delrin, silicon wafer, glass, metal or biodegradable/non-biodegradable polymer-based, 3D microstructured, flexible films. It was demonstrated that this novel method can be universally applied to many different natural or synthetic polymer-based films or any other solid substrates with proper pattern to create graphene-based conductive electronic circuits. This approach also enables fabrication of 3D circuits of flexible electronic films or solid substrates. It is a green process preventing the need for expensive and harsh postprocessing requirements for other fabrication methods such as ink-jet printing or photolithography. We reported that it is possible to fill the pattern channels with different dimensions as low as 10×10 μm. The graphene nanoplatelet solution with a concentration of 60 mg/mL in 70% ethanol, pre-annealed at 75° C. for 3 h, provided ˜0.5-2 kOhm resistance. The filling of the pattern channels with this solution at a flow rate of 100 μL/min created a continuous conductive graphene pattern on flexible polymeric films. The amount of graphene used to coat 1 cmof area is estimated as ˜10 μg. A second method regarding the transfer of graphene material-based circuits with small features size (5 μm depth, 10 μm width) from any solid surface to flexible polymeric films via polymer solvent casting approach was demonstrated. This method is applicable to any natural/synthetic polymer and their respective organic/inorganic solvents.