Cone-jet printing of aligned silver nanowire/poly(ethylene oxide) composite electrodes for organic thin-film transistors

Aligned silver nanowire (AgNWs) conductive electrodes are printed through an electrohydrodynamic (EHD) jet printing via cone-jet mode. We investigate effects of poly(ethylene oxide) (PEO) addition to AgNW inks in terms of surface energy, ink viscosity, and electrical conductivity. The optimized PEO content in the ink is determined to be ∼10 wt%, at which well-defined AgNWs/PEO composite electrodes aligned along the printing direction can be prepared by cone-jet mode of EHD jet printing. We fabricate bottom contact organic thin film transistors (OTFTs) with TIPS-pentacene/PS blend as a semiconducting layer to take advantage of printed AgNWs/PEO electrodes. The resulting devices exhibit stable transfer characteristics for 12 h even in ambient air with average field-effect mobility (μ_FET), threshold voltage (V_th) and on/off current ratio (I_on/I_off) of 0.51 cm²/V, −2.0 V, and ∼10⁶, respectively. To understand the characteristics of OTFTs based on AgNWs/PEO composite electrodes in detail, we examine crystalline morphology and molecular orientation of TIPS-pentacene/PS blend on various substrates through field emission scanning electron microscopy and two-dimensional grazing incidence X-ray diffraction, respectively.