A Robust Nonvolatile Resistive Memory Device Based on a Freestanding Ultrathin 2D Imine Polymer Film

Abstract

Here, the synthesis of a wafer-scale ultrathin 2D imine polymer (2DP) film with controllable thickness from simple benzene-1,3,5-tricarbaldehyde (BTA) and p-phenylenediamine (PDA) building blocks is reported using a Schiff base polycondensation reaction at the air-water interface. The synthesized freestanding 2DP films are porous, insulating, and more importantly, covalently linked, which is ideally suited for nonvolatile memristors that use a conductive filament mechanism. These devices exhibit excellent switching performance with high reliability and reproducibility, with on/off ratios in the range of 10² to 10⁵ depending on the thickness of the film. In addition, the endurance and data retention capability of 2DP-based nonvolatile resistive memristors are up to 200 cycles and 8 × 10⁴ s under constant voltage stress at 0.1 V. The intrinsic flexibility of the covalent organic polymer enables the fabrication of a flexible memory device on a polyimide film, which exhibits as reliable memory performance as that on the rigid substrate. Moreover, the 2DP-based memory device shows outstanding thermal stability and organic solvent resistance, which are desirable properties for applications in wearable devices.

Keywords: 2D imine polymers; covalent organic frameworks; flexible devices; memristors; nonvolatile memory.