Drop-on-demand printing of carbon black ink by electrohydrodynamic jet printing.

Electrohydrodynamic (EHD) jet printing is a technique using electric fields to eject inks through nozzle apertures. EHD jet printing is very attractive due to its non-contacting nature and compatibility with diverse materials and substrates. In this research, we have fabricated micron-sized dot arrays and line patterns with carbon black ink on Si wafer substrates using EHD jet printing. The effect of operating conditions such as applied voltage, working distance and stage speed on the size and shape of the jetted patterns and jetting cycles is investigated by using optical microscope, high speed camera and atomic force microscopy (AFM). We have also demonstrated the drop-on-demand feature of the EHD jet printing system by patterning carbon black ink lines with various widths and dot arrays with desired diameters and spacing by controlling the operating conditions.

Direct-patterning of porphyrin dot arrays and lines using electrohydrodynamic jet printing.

In this research, we have fabricated micron-sized patterns of porphyrins on silicon substrates using an electrohydrodynamic (EHD) jet printing technique. Optical and fluorescence microscopies have been used to examine the shape and fluorescence property of porphyrin patterns. The morphology of the porphyrin patterns printed with variously formulated porphyrin inks and the effects of applied voltage, working distance, and substrate properties on the morphology of patterns were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). We have also demonstrated the acid-vapor sensing capability of the porphyrins by exposing the porphyrin patterns on Si substrates to nitric acid vapor.