Tip-guided coaxial electrohydrodynamic printing of P3HT nanowire arrays for flexible organic field-effect transistors

Abstract

High-resolution, ordered printing of polymer semiconductor nanowires is important for flexible organic electronics, yet nanoscale deposition remains challenging because charged electrohydrodynamic (EHD) jets are sensitive to electric-field disturbances. Here, we examine a tip-guided coaxial EHD printing strategy for fabricating ordered poly(3-hexylthiophene-2,5-diyl) (P3HT) nanowire arrays. A grounded tungsten-steel tip electrode beneath the electrically insulating deposition substrate focuses the local electric field near the deposition zone. Compared with otherwise identical coaxial printing without the tip, the tip-guided configuration produced straighter deposition trajectories and more ordered arrays. Among five representative measurements obtained under the optimized condition, the smallest locally observed linewidth was 90 nm and the mean was approximately 200 nm. Flexible organic field-effect transistors based on the printed nanowires exhibited a maximum extracted mobility of 0.04 cm2 V−1 s−1 and an on/off ratio exceeding 104. This work examines passive collector-side field focusing in nanoscale EHD printing of polymer semiconductors.