Polyimide (PI) high-quality polymer dielectric films with the features of anti-solvents and large-area consistency for field-effect transistors

Abstract

In this work, the properties of polyimide (PI) as a dielectric film are systematically investigated. PI films are processed using a spin-coating method under various conditions. Subsequently, the leakage current, unit-area capacitance and morphologies of these films are characterized. Then the anti-solvent property is certified upon comparing the films before and after solvent treatment. Organic field-effect transistors based on PI dielectric films and pentacene active films show uniform performance distribution over a large area. Furthermore, a single crystal of 2,7-dihexyl-dibenzo[d,d′]thieno[3,2-b;4,5-b′]dithiophene (C6-DBTDT) is obtained on the PI film using a solution-processed method and exhibits good electrical properties with the highest mobility of 3 cm² V⁻¹ s⁻¹ and I_on/I_off > 10⁵. It is believed that this kind of PI polymer dielectric film has potential applications in solution-processed, flexible and large-area organic electronics.