Optimization of graphene conductive ink using solvent exchange techniques for flexible electronics applications

Abstract

In the development of the flexible electronics industry, creating high stability and environmentally friendly conductive inks has remained a key challenge. In this study, less-toxic solvent exchange techniques graphene conductive inks were printed on polyethylene terephthalate substrate. This study aimed to investigate the properties of graphene conductive ink prepared by solvent exchange techniques using four combinations of solvents. To this end, four combinations of solvents were used to fabricate the graphene conductive inks, namely, dimethylformamide (DMF): xylene, DMF: toluene, DMF: ethanol, and DMF: acetone. Conductive ink fabricated by DMF: ethanol solvent exchange was produced with a higher degree of stability and wettability, as well as a 5% enhancement of electrical conductivity, in comparison with other solvent exchange solutions. The findings showed that the electrical conductivity of conductive film increased with an increase of 45% printing cycles. Furthermore, it has been observed that the electrical conductivity of printed graphene film decreased at only 0.02% even over 10 times of bending cycles. Therefore, the combination of DMF: ethanol solvent exchange is the most suitable formulation for graphene conductive inks.