Vertical-Resolved Composition and Aggregation Gradient of Conjugated-Polymer@Insulator-Matrix for Transistors and Memory

Conjugated polymers are of interest for next-generation electronics due to their improved flexibility, low cost, and solution processability. However, a conjugated polymer is not a chemically “pure” material because the polymer chains are polydispersed in terms of molecular weights and/or chemical stereoregularities, leading to dispersions of both localized order and electronic properties. Taking advantage of these properties, a one-step self-refinement method is proposed to induce film-depth-resolved composition and aggregation gradient of conjugated-polymer@insulator-matrix for high-performance organic field-effect transistors and nonvolatile memories. During solvent evaporation, the higher ordered sub-components of conjugated polymers are substantially enriched at the top surface of the blend film to form a morphologically continuous sublayer serving as high-quality transport pathways to warrant high-performance transistors. The less ordered sub-components are distributed within insulator-matrix in the bottom part of the film without connection with each other, which guarantees a reliable composite electret to help store sufficient immobilized charges to tune the operation of the device. Moreover, these conjugated-polymer@insulator-matrix films with insulator content as high as 95% show excellent optical transparency (>90%) and environmental stability (for months), which demonstrates great potential for use in transparent electronics.