Lab-Made Graphite and Silver Conductive Inks for the Fabrication of Printed Electrodes

This study presents the development of lab-made graphite and silver conductive inks for the fabrication of mask-based printed electrodes. The graphite ink was formulated using glass varnish, graphite powder, acetone, and propylene glycol, whereas the silver ink was composed of silver powder, glass varnish, and acetone. The influence of ink composition, curing temperature, and curing time on the electrical properties of the inks was investigated. The optimized graphite ink containing 6.4% propylene glycol exhibited the best electrochemical performance, with a curing temperature of 40°C for 15 min. Silver ink, used as the pseudo-reference electrode, was cured at 25°C for 5 min. The electrodes were fabricated by printing inks on a polyester substrate, and their electrochemical behavior was evaluated using cyclic voltammetry in a Fe(CN)₆^3−/4− redox probe. Miniaturization of the electrochemical cell was achieved, reducing the working electrode area from 24.54 to 8.35 mm². The electrodes underwent electrochemical pretreatment in an alkaline medium, resulting in improved electron transfer kinetics and increased peak current. Scanning electron microscopy revealed a homogeneous and rough electrode surface with an increased electroactive area after pretreatment. The reproducibility and stability of the electrodes were assessed, and they demonstrated satisfactory performance over multiple cycles and different fabrication batches. The cost analysis showed that lab-made electrodes could be produced at a significantly lower cost compared to commercial electrodes. The graphite and silver inks developed provide a cost-effective and reliable solution for the fabrication of electrodes, offering potential applications in electrochemical sensing and analysis.