Effect of processing temperature on performance of screen-printed graphite electrodes

Graphite thick films have been considered as an effective integrated working electrode in disposable electrochemical sensors for the on-site detection of pollutants in remote locations. The processing conditions of graphite thick films are not well documented, which hinders progress in their use. By combining profilometry, optical microscopy, X-ray powder diffraction, and Raman spectroscopy, we show that the structural development of graphite thick films strongly depends on the processing temperature. After thermal annealing of the screenprinted paste, the arrangement of the graphene layers improved and the organic components from the paste facilitated the fragmentation of the graphite grains. The resulting sheet resistance of the thick films decreases and contributes to a higher electron-transfer rate and thus to faster redox processes at the electrode surface. The elucidation of the relationship between processing and properties offers new opportunities to customise the properties of graphite thick films for a variety of applications requiring defect engineering.