Heteroatom-doped graphene oxide-based conductive ink: synthesis, characterization and investigation of the conductivity properties for flexible sensor technology

Abstract

The desire for real-time and continuous human health monitoring and uninterrupted human–machine interaction has been increasing exponentially day by day. This has opened new windows in the development of wearable devices. In particular, graphene oxide as a new 2D material has become interesting in wearable sensors thanks to its superior thermal, mechanical and electrical properties. Conductive inks containing graphene materials have been shown to be an attractive approach to produce flexible, disposable, wearable and miniature devices with desirable properties. In this study, a conductive ink containing sulfur-doped graphene oxide (S-GO), polyvinylidene fluoride (PVDF) and N-methyl-2-pyrrolidone (NMP) was synthesized and was coated on a polyester/cotton blended fabric substrate by the “dip and dry” method. Then, conductive fabric electrodes (CFEs) were prepared. S-GO was synthesized in one-step, inexpensive, easy, and environmentally friendly with a constant potential. FTIR, EIS, SEM-EDS, AFM, XRD, XPS, Raman spectroscopy and tensile tests were used for the characterization of the CFEs. The electrochemical behaviors of biological substances such as dopamine (Dop), ascorbic acid (AA), NADH and uric acid (UA) were investigated using the CFE for the first time in the literature. It is predicted that the CFE developed according to the obtained results can offer new opportunities for the required flexible, low-cost, wearable electronics and sensors.