Contact line curvature-induced molecular misorientation of a surface energy patterned organic semiconductor in meniscus-guided coating

The printing of organic semiconductors (OSCs) by means of meniscus guided coating (MGC) has great potential for the fabrication of high-performance, uniform, and large area flexible electronics. Furthermore, surface energy patterning allows low-cost, large area manufacturing, and is a requirement for device isolation to achieve accurate drive and to minimize power consumption. We investigated the morphological and electrical characteristics of surface energy patterned OSCs coated using the MGC method. A unique phenomenon, contact line curvature-induced molecular misorientation effect, which occurs in the patterning of OSCs with the MGC method, is demonstrated. This effect is highly dependent on the pattern width which decided contact line curvature. It influences the charge transport properties and hence the field-effect mobility of organic thin-film transistors (OTFTs). OTFTs in widths ranging from 50 to 500 µm were fabricated. The highest misorientation angle was induced in the 50 µm pattern width and the corresponding OTFTs exhibited the highest mobility.