Polymer-Gated Transistors with Only One Solution-Processed, Single Crystalline Organic Microwire for Light and Oxygen Detection

Organicsemiconductors employed in single crystalline form haveseveral advantages over polycrystalline films, such as higher chargecarrier mobility and better environmental stability. Herein, we reportthe fabrication and characterization of a solution-processed microsizedsingle-crystalline organic wire of n-type N,N '-dipentyl-3,4,9,10-perylenetetracarboxylic diimide (PTCDI-C-5). The crystal was appliedas an active layer in polymer-gated organic field-effect transistors(OFETs) and organic complementary inverter circuits. The single crystaiilinenature of PTCDI-C-5 wires were characterized using two-dimensionalgrazing incidence wide-angle X-ray diffraction (2D-GIXD) and polarizedoptical microscopy. OFETs with the PTCDI-C-5 crystals exhibitedhigh n-type performance and air stability under ambientconditions. To investigate the electrical properties of the single-crystallinePTCDI-C-5 wire more precisely, OFETs with only one PTCDI-C-5 microwire in the channel were fabricated, and clear n-type characteristics with satisfactory saturation behaviorwere observed. The device with only one crystal wire exhibited characteristicswith significantly lower variation compared to the multicrystal devices,which shows that the density of crystal wires is a critical factorin precisely investigating device performance. The devices exhibiteda reversible threshold voltage shift under vacuum and oxygen conditions,without changing the charge carrier mobility. Light-sensitive characteristicswere also observed. Additionally, this solution-processed, highlycrystalline organic semiconductor can be used in high-performanceorganic electronic circuits as well as in gas or light sensors.