Dimatix dmp 2831

EG-OFETs with an inkjet-printed organic semiconductor were prepared on a flexible and PEN substrate as previously reported [24 (link)]. Afterwards, the samples were cleaned in acetone and 2-propanol (IPA) under ultrasonication, gently dried with a nitrogen flow and additionally cleaned for 2 min by means of oxygen plasma. S and D electrodes were photolithographically defined, possessing a 10.5 mm (width) × 5 μm (length) channel, while the circular lateral gate (LG) exhibited a radius of 1.25 mm. P3HT (2.6 mg/mL) was dissolved of in a mixture of chlorobenzene (CB) and o-dichlorobenzene (ODCB), 75:25 v/v, and inkjet-printed with a Fujifilm Dimatix DMP-2831. Details on the printed EG-OFET fabrication and operational stability in a water environment have been reported elsewhere [24 (link)].

Hydrophobic dot arrays were manufactured by printing fluorine-silane material. The fluorine-silane material (Fluorolink S10®) was purchased from Solvay Solexis. According to the product data sheet, the material composed of perfluoropolyether with ethoxysilane terminal groups that reduce surface energy of applied substrates thereby improving the repellency to water. The material has a high kinematic viscosity of 18,000 cst at 20 °C, which is too high to be suitable for the use of ink. A fluid of SU-8 developer purchased from Microchem was revealed to be a proper diluent for the printable PFP ink. 1.2 mL of PFP was diluted with 2 mL of SU-8 developer. This volume ratio was determined to sustain the printer cartridge as long as possible. A piezoelectric inkjet printer (Dimatix DMP-2831, Fujifilm) was used to deposit the polymer dot arrays. The printer head is composed of an array of 16 nozzles with 21.5 μm opening size. Stable droplets were ejected onto the stainless steel (SS 304) substrate by setting 11.5 μs and 24 V pulse at a frequency of 20 kHz (Fig. S1). The polymer dot size was determined by physical and chemical properties of the polymer inks and substrate, and the smallest one with 75 μm diameter dots was obtained under our current processes. Printing pattern drawing was achieved by software installed in the printer.

P(NDI2OD-T2) (purchased from Polyera) is dissolved in mesitylene at a concentration of 5 mg/ml. After fabrication of the bottom contacts via laser sintering, P(NDI2OD-T2) is deposited through bar-coating in air atmosphere, using the same process as described in ref. 2 (link). Then poly(methyl methacrylate) (PMMA) is spun from n-butylacetate (concentration 80 mg/ml) at 1500 rpm for 1 minute. After dielectric deposition, the devices are annealed on a hotplate for 30 min at 80 °C for residual solvent removal. PEDOT:PSS (Clevios P Jet 700) is patterned over the contacts and channel area via inkjet (using a Fujifilm Dimatix DMP-2831). The devices are then annealed at 120 °C in nitrogen atmosphere for 12 h.