Inkjet printing of well-adapted PEDOT-PSS dispersions

Poly (3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT-PSS) is a popular conductive polymer that finds widespread use in the fields of polymeric electronics and display applications. Its major advantages lie in the suitability for flexible electrical devices and the relatively simple deposition process capabilities with techniques such as inkjet printing. However, the deposition of PEDOT-PSS dispersions with inkjet printheads can cause a number of problems due to possible interaction of the fluids with the printhead, and due to poor inkjet functionality and layer formation on the substrate. In the present work we have adapted PEDOT-PSS dispersions for improved performance in a Xaar-type piezoelectric inkjet printhead, in particular for high quality drop formation and for reduced corrosion of the inkjet printhead. At the same time the best PEDOT-PSS inks regarding layer formation and conductivity were identified. As an application example, a passive LCD device incorporating an inkjet printed PEDOT-PSS electrode pattern that was produced with an adapted PEDOT-PSS ink is presented.