A Coordinated-Metal-Synergetic Covalent Organic Framework Memristive Device for Highly-Efficient Neuromorphic Application

Abstract

Two-dimensional covalent organic frameworks (2D COFs) have emerged as promising candidates for memristor applications due to their large surface area, rich active sites, and regular framework structure. However, because of their poor intrinsic conductivity, most of 2D memristive COFs rely on the conductive filaments (CFs) mechanism, which are prone to generating excessive and disorderly CFs growth, posing a challenge to the stability of device performance. To address this issue, we precisely incorporate metal conductive atoms into the framework and synthesize a coordinated-metal-containing COF (CMC-COF) as an efficient memristive material. This strategy greatly enhances the conductivity of 2D COF and achieves stable multi-state switching based on its intrinsic stepwise charge transfer (ISCT) effect rather than random CFs. The bio-synaptic mimicking behavior of devices affords a high CNN-based digital recognition accuracy over 97%. Furthermore, a multi-color 2D QR code is developed for the construction of the brain-inspired cognitive system, enabling more convenient item coding and information encryption. To our knowledge, this is the first report of utilizing 2D CMC-COFs to realize neuromorphic devices. This work sets an example for developing highly feasible metal-containing nanocrystalline organic framework materials to implement neuromorphic computing and intelligent cognitive applications.

Keywords: Covalent organic frameworks, charge transfer, memristors, artificial synapses, neuromorphic computing