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

Abstract

Abstract 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.

Keywords

• organic field‐effect transistors
• organic memory
• polymer blends
• polymer electrets
• vertical phase separation