A molecularly engineered polymer dielectric with pyrene functionalization for organic transistors and circuits with reduced hysteresis

Abstract

The use of polymers as gate dielectrics in organic field-effect transistors (OFETs) offers key advantages such as chemical compatibility with diverse organic semiconductors and substrates, structural tunability, and suitability for low-temperature processing toward large area, uniform film fabrication. However, many solution-processable polymer dielectrics contain reactive functional groups, particularly hydroxyl (–OH) groups, which introduce hydrophilicity. This often leads to weak interfacial compatibility with hydrophobic organic semiconductors, resulting in low device performance under ambient conditions. Nevertheless, these reactive groups provide an opportunity to engineer the chemical structures of dielectrics. In this study, we chemically modified poly(melamine-co-formaldehyde)methylated (PMF) with inherent hydroxyl groups as reactive sites using 1-pyrenebutyric acid (PYBA), introducing pyrene moieties that effectively tailor the surface energy, enhance interfacial stability, and suppress hysteresis in organic devices. Notably, the pyrene units introduced on the dielectric surface enhanced the interfacial compatibility with polycyclic aromatic semiconductors such as pentacene and 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) via favorable π–π interactions, leading to desirable semiconductor film growth, suppressed hysteresis, and more efficient charge transport. In addition, a complementary-type inverter using TIPS-pentacene (p-type) and N,N′-dipentyl-3,4,9,10-perylenedicarboximide (PTCDI-C₅) (n-type) crystals exhibited a high gain (30.2) with large noise margins. These interfacial improvements, combined with a low-temperature, solution-processable fabrication route, make pyrene-functionalized PMF a promising gate dielectric for high-performance, low-hysteresis OFETs and organic electronic circuits.