Electrohydrodynamic‐Printed Polyvinyl Alcohol‐Based Gate Insulators for Organic Integrated Devices. Issue 4 (14th September 2021) - Jung, Cheolmin
Abstract : Organic printable dielectric layers are required for next‐generation electronic circuits, particularly those used as gate insulators (GIs) in organic field‐effect transistors (OFETs). Herein, optimized electrohydrodynamic (EHD) jet printing with an electrostatic force‐assisted mode is suggested for the fabrication of polyvinyl alcohol (PVA)‐based dielectric patterns after careful consideration of the ink system. The PVA molecules maintain good solubility in polar solvents, even when a crosslinking agent is added, which enables a continuous PVA jet stream with a width smaller than the diameter of the nozzle to be stably obtained. Subsequent EHD printing produces uniform PVA patterns with a smooth surface morphology suitable for the crystal growth of overlying organic semiconductors. The addition of a crosslinking agent in PVA results in direct GI patterns that exhibit superior insulating properties with high dielectric strength as compared with PVA without crosslinking agents. The OFETs with PVA‐based GIs prepared with EHD printing show stable operation with low gate leakage currents. In addition, the feasibility of EHD‐printed PVA layers is demonstrated for application as GIs in organic complementary logic gates. Abstract : Electrohydrodynamic (EHD) printing produces uniform polyvinyl alcohol (PVA)‐based gate insulators (GIs), even after adding optimized crosslinking agent (PMF). PMF effectively cross links the printed GIs that show high dielectric strength. Fully covering the patterned gate electrodes with printed GIs enables to fabricate integrated devices, including complementary inverters, and NAND/NOR logic gates, showing good switching performances.