Organic thin-film transistors with novel high-k polymers as dielectric layers

This study describes a general approach to design and synthesize a series of novel high-k polymers containing π-conjugated structures with cyano groups for use as a dielectric layer in organic thin-film transistors (OTFTs). The polymer dielectric films have been evaluated based on surface morphology, dielectric constant, leakage current density and compatibility with organic semiconductors, which can be readily fabricated via solution processes in an ambient atmosphere. The characterization confirms that the π-conjugated structures with cyano groups can provide a high dielectric constant (high-k) and a low electrostatic loss. With these polymer dielectric layers, para-sexiphenyl (p-6P)/vanadyl-phthalocyanine (VOPc) OTFTs exhibit excellent performances with a threshold voltage of −3.22 V, a charge carrier mobility of 0.49 cm2 V−1 s−1, and an on/off current ratio >106.