Electrohydrodynamic jet printing of small-molecule semiconductor crystals on chemically patterned surface for high-performance organic field-effect transistors

Direct writing of organic semiconducting crystals by electrohydrodynamic jet (EHD) printing has enabled the low-cost large-area fabrication of organic semiconducting crystal arrays without the need of complicated patterning procedures. However, morphological variations within a single printed pattern (e.g., variations in thickness, crystallinity, and local crystal orientation) caused by the “coffee-ring effect” can be an issue during their application in organic field-effect transistors (OFETs) since their charge-transport properties significantly affect the device characteristics. Herein, we report the EHD printing of small-molecule semiconducting crystals on a chemically patterned substrate to suppress the “coffee-ring effect” and produce uniform high-quality crystals oriented along the printing direction. The EHD printing of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-PEN) on hydrophobic polyurethane acrylate line patterns on a dielectric surface enables the selective and guided growth of the crystals. The OFETs with the TIPS-PEN crystals printed on the patterned surface exhibit an average field-effect mobility of 0.34 cm 2 /(V s), which is more than twice of that of the OFETs fabricated with crystals grown on unpatterned surfaces. Thus, the use of chemically patterned surface to improve the uniformity and crystallinity of organic semiconducting crystals is expected to promote the application of EHD printing for fabricating high-performance OFETs. • Highly uniform TIPS-PEN semiconducting crystal array can be fabricated on the patterned surface by using EHD jet printing. • A patterned substrate can produce crystals aligned uniaxially along the printing direction without coffee-ring effect. • OFETs with the narrowest TIPS-PEN crystals (5 μm width) yield the average field-effect mobility of 0.34 cm 2 /(V s).