Two‐Dimensional Conjugated Microporous Polymer with Structural Stability and Electrical Bistability for Rectifying Memory Array

Pan

Zhu

et al. 2023

ACS Appl. Nano Mater.

Self Cite

Tuning memory windows is vital for cross-bar memory architectures with low power and free cross-talk. Herein, we demonstrate a synergistic interface/electrode nanoengineering strategy to tune memory windows for low power operation and enhanced electrical readout in polymer devices; this approach is workable for most insulating or semiconducting polymeric mediums. Through customizing the resistivity of selectively reduced graphene oxide nanoelectrodes, an inherent sub μA current is recorded in the programming storage state. The nanocavity of the polymer interface can reduce the switching voltage due to local electric field enhancement, thus leading to tunable memory windows. By stacking a selector onto the memory, the vertical architecture features dynamic memory kinetics, enabling cross-talk-free readout by suppressing sneak leakage current paths.

Section: Resultsmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Polymer Memristive Layer with Reduced Graphene Oxide and Al Electrodes for Tunable Memory Windows with Low-Power Operation and Enhanced Electrical Readout

Pan

Zhu

et al. 2023

ACS Appl. Nano Mater.

Self Cite

“…Huang et al [202] designed and constructed a resistive memristor based on a large area 2D CMP film synthesized from surface-confined polymerization, featuring rewritable nonvolatile memory with a low set voltage in a graphene/CMP/metal diode. By assembling the solution-processable all-polymer one diode-one resistor (1D1R) cross-bar memory array by directly stacking the CMP memristor with a poly(3-hexylthiophene) rectifier, the sandwich structured CMP device exhibited nonvolatile flash performance, with features of low set voltage (≈1.65 V), stable cycling endurance (>25 cycles), and long retention time (10 4 s).…”

Section: Resistive Memorymentioning

confidence: 99%

Macroscale Conjugated Microporous Polymers: Controlling Versatile Functionalities Over Several Dimensions

et al. 2022

covalently bonded organic moieties. Because of their unique properties derived from their tunable porous structures and the multiple functional groups, which can be included in their backbones, POPs have been actively investigated for multiple applications including gas storage/separation, [2,3] catalysis, [4][5][6] optoelectronics, [7,8] sensing, [9][10][11] energy storage, and conversion. [12,13] Aside from their high specific surface areas, they furthermore show excellent chemical stability, light-weight and a versatile chemistry for modification and functionalization. POPs can be further classified into two categories based on their crystallinity. Crystalline POPs are usually summarized under the name covalent organic frameworks [14][15][16] (COFs). Amorphous POPs are further divided, based on their structure or construction principles into hyper-crosslinked polymers [17,18] (HCPs), polymers of intrinsic microporosity [19,20] (PIMs), porous aromatic frameworks [21,22] (PAFs), and others. Recent research has seen increasing interest on amorphous POPs, especially when their skeleton is π-conjugated. In these highly porous networks, π-conjugation is superimposed with meso-/microporosities, i.e., electron transport in the polymer backbone is accompanied by mass transport in the porous system, which enable many intriguing properties and applications, e.g., in energy storage and conversion, [23,24] or optoelectronics. [25,26] As such, the importance of π-conjugation in porous polymer networks has defined another emerging functional POP class-the conjugated microporous polymers (CMPs). As mentioned, such CMPs [27] are a unique class of POPs exhibiting extended π-conjugated structures and permanent nanopores (Table S1). Earlier, McKeown et al. [28] discussed an important concept of preparing robust nanoporous materials by the covalent binding of planar molecules via a rigid spirocyclic linker. In 2007, Cooper et al. [29] reported a highly cross-linked, microporous poly(arylene ethynylene)s network, thus the first microporous polymer network with distinct π-conjugation and introduced the term "conjugated microporous polymer (CMP)" for this class of materials. Since their discovery, CMPs chemistry has intrigued scientists across the globe and been promoted rapidly, resulting in a strong growth in publications over the last decade. For instance, Thomas et al. [30] reported a spirobifluorene-type CMP with stable interface and application potential in organic light emitting diodes Since discovered in 2007, conjugated microporous polymers (CMPs) have been developed for numerous applications including gas adsorption, sensing, organic and photoredox catalysis, energy storage, etc. While featuring abundant micropores, the structural rigidity derived from CMPs' stable π-conjugated skeleton leads to insolubility and thus poor processability, which severely limits their applicability, e.g., in CMP-based devices. Hence, the development of CMPs whose structure can not only be controlled on the micro-but also on the macroscale have...

“…Notably, to get neat films, the substrates are recommended to be placed vertically or face-down because the bulk particles of COF can be also obtained during the reaction. So far, COF film growth has been achieved on various substrates, such as 2D materials (graphene, , rGO, hBN), metal oxide (ITO, − ZnO), metal, and glass . Mostly, the COF layers are stacked and accumulated in the direction parallel to the substrate surface to form a vertically orientated film.…”

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confidence: 99%

“…COF-based resistive switching memories generally possess a metal–insulator–metal (MIM) device structure that enables resistance (conductance) switching between high-resistance state (HRS) and low-resistance state (LRS), demonstrating a nonvolatile memory behavior. ,− ,,− Such simple device architectures facilitate further scaling-down with a crossbar array geometry for high-intensity integration, which is promising for high-density data storage and neuromorphic applications. Generally, the resistance switching mechanisms in organic materials are explained by conductive filament, charge trapping/detrapping, charge transfer, redox reaction, and conformation change …”

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confidence: 99%

Covalent Organic Frameworks for Neuromorphic Devices

Jia

et al. 2023

J. Phys. Chem. Lett.

Neuromorphic computing could enable the potential to break the inherent limitations of conventional von Neumann architectures, which has led to widespread research interest in developing novel neuromorphic memory devices, such as memristors and bioinspired artificial synaptic devices. Covalent organic frameworks (COFs), as crystalline porous polymers, have tailorable skeletons and pores, providing unique platforms for the interplay with photons, excitons, electrons, holes, ions, spins, and molecules. Such features encourage the rising research interest in COF materials in neuromorphic electronics. To develop high-performance COF-based neuromorphic memory devices, it is necessary to comprehensively understand materials, devices, and applications. Therefore, this Perspective focuses on discussing the use of COF materials for neuromorphic memory devices in terms of molecular design, thin-film processing, and neuromorphic applications. Finally, we provide an outlook for future directions and potential applications of COF-based neuromorphic electronics.