Optimization of print quality of inkjet printed PEDOT:PSS patterns

Abstract

This work investigates which factors and interactions are more influential in the inkjet printing process of conductive poly (3, 4-ethylenedioxythiophene):poly (styrenesulfonate) patterns. The chosen experimental design is an L16 Taguchi experiment with seven different factors with two levels each and eight interactions. The studied factors are printhead voltage, print resolution, substrate temperature, substrate treatment, printhead height, printhead velocity, and the number of printed layers. The analyzed dependent variables are printing accuracy, printing error ratio, and electrical resistance. The results suggest that the resolution, substrate treatment, and printhead height are the most influential factors affecting printing quality, whereas the electrical resistance output is mainly determined by the print resolution, the substrate treatment, and the number of printed layers. Some interactions are also identified between print resolution and substrate treatment, print resolution and number of layers, and substrate temperature and printhead velocity. Some conclusions indicate that lower print resolution benefits printing accuracy, but hinders the electrical conductivity. Furthermore, it was found that plasma treatment can be counterproductive for the printing quality, but beneficial for the electrical conductivity of the patterns. Moreover, great electrical conductivity can be obtained for a lower number of printed layers, as long as the print resolution is increased. Lower printhead height also strongly benefits the printing quality.