Spray-printed organic field-effect transistors and complementary inverters

Abstract

We report the fabrication of high-performance organic field-effect transistors (OFETs) and complementary inverters using spray-printed films of n-type small-molecule semiconductors and p-type conjugated polymers. Highly crystalline organic semiconductor films could be obtained by controlling the droplet size, nozzle-to-substrate distance, and solvent drying speed during the printing process. After the optimisation of the spray-printing process, the performances of the spray-printed OFETs were comparable to those of spin-coated and inkjet-printed OFETs. In addition to excellent device-to-device uniformity, the spray-printed n- and p-channel OFETs also exhibited high field-effect mobilities, which were similar to 0.3 (ActivInk (TM) N1450, Polyera), similar to 0.01 (regioregular-poly(3-hexylthiophene) (rr-P3HT)), and similar to 0.25 cm(2) V-1 s(-1) (ActivInk (TM) P2100, Polyera). Organic complementary inverters were fabricated by spray printing and shadow-mask patterning while using ActivInk (TM) N1450 and P2100 as the n- and p-type semiconductors, respectively. The complementary inverters exhibited a large voltage gain (similar to 17) and a low power consumption (similar to 0.02 mW) at V-DD = 60V.