Bin Zhang

Molecular memristors have shown great potential for digital memory and analog computing applications. However, developing molecular active layers with controllable structures and stable electrical properties remains challenging. Here, we employ a triphenylamine centered three armed terpyridine ligand (TPA‐(TPy) ₃ ) to construct a two‐dimensional (2D) iron based metal–organic network (Fe‐MON) film through interfacial coordination assembly. The three‐armed molecular topology promotes lateral network growth, enabling the formation of continuous and robust Fe‐MON films. In contrast, the structurally analogous two‐armed ligand (TPA‐(TPy) ₂ ) fails to generate continuous networks, resulting in inferior device stability. The resulting Al/Fe‐MON/ITO memristors exhibit reliable digital resistive switching characteristics with narrow ON/OFF voltage distributions, good retention, and endurance. Moreover, the synergistic redox activity of triphenylamine and Fe ²⁺ /Fe ³⁺ centers enables continuous conductance modulation under pulse stimulation, achieving 64 distinguishable multilevel conductance states. By integrating these conductance states into a convolutional neural network (CNN), the system achieves 96.57% accuracy in flower image recognition. This work demonstrates the capability of 2D metal–organic network films for digital‐analog dual‐mode memristors.

Covalent organic frameworks (COFs) offer a tunable platform for optoelectronic memristors by coupling light absorption with history‐dependent conductance, yet their potential remains underexplored. This review systematically examines how structural features, including linkage chemistry, donor–acceptor organisation, dimensionality, layer stacking, photochromic groups, redox centres and pore environments, govern the generation and stabilisation of excited, charged, isomeric and ionic states. It then traces the translation of these states into device‐level conductance modulation via molecular switching, photoredox reactions, charge trapping, interfacial photogating and ion or filament motion, with special emphasis on film quality, electrode contacts and semiconductor heterointerfaces. Functional capabilities such as temporal plasticity, bidirectional programming, spectral encoding, adaptive vision, denoising, motion recognition and task‐specific sensing are critically assessed, distinguishing genuine device responses from software simulations and physically integrated arrays. From this analysis, three design rules emerge: charge separation must operate within a reversible kinetic window, the stored state should be identifiable independently of conductance, and framework architecture must align with the device current path. The primary opportunity lies in linking chemically defined state variables to optically addressable conductance, whereas major challenges include incomplete mechanistic validation, limited device statistics, environmental instability and the lack of fully integrated addressable COF arrays. The review concludes with priorities for mechanism‐resolved characterisation, scalable processing and circuit integration.

The rapid synthesis and scalable design strategies of high‐reliability multi‐dimensional and multi‐topological covalent organic frameworks (MDT COFs) are of great significance for meeting the diverse technological application requirements with highly differential specific demands, especially in neuromorphic electronics. Here, we introduce aniline into a sonochemical synthesis platform, where thermodynamic‐kinetic synergistic control expands topological diversity and substrate compatibility. We synthesized 37 COFs covering 1D to 3D, including 10 previously unreported frameworks. Relying on a parallel optimization strategy involving geometric‐electronic co‐engineering, a 3D TAPPFe‐Cu ₃ COF‐based wafer‐scale memristor incorporating multiple metal and redox centers is designed and applied to shortest‐path optimization in the Shanghai metro network, exhibiting an 80.1% reduction in energy consumption, 78.6% faster synaptic weight reset, and a 9.36‐fold improvement in TDDB lifetime compared with state‐of‐the‐art COF‐based devices. This synthetic methodology and material design strategy provide a robust foundation for application‐tailored high‐reliability COFs, while opening new avenues for diversified utilization of MDT COFs.

Olefin‐linked covalent organic frameworks ( cc COFs) have shown great advantages in the community since discovery. However, the synthesis of ccCOFs highly relies on unsaturated heteroatom‐involved segments (uSHS) to activate C─H bond to produce carbanion and to further condense with aldehydes. Such electron‐withdrawing uSHS have long hindered the wide applications of ccCOFs in optoelectronic devices due to the strong electron‐withdrawing effect. In this work, we report a carbenium‐involved synthesis of cc COFs without uSHS’ participating. As‐synthesized ionic cc COFs show good crystallinity and ultra‐narrow bandgap down to 1.03 eV without introducing complicated donor‐acceptor building blocks. Such cc COFs can also be directly synthesized as uniform films on different substrates, for example, glass, silicon wafer, Au, and so on. Most impressively, the device Au/2DPPPV‐102/Al exhibits 32 distinct conductance states under low‐voltage sweeps and each conductance state demonstrated excellent non‐volatility and could be maintained stably for over 5000 s, which are typical features of memristor. A convolutional neural network was implemented using a 32‐conductance‐state memristor array and applied to image recognition, yielding recognition accuracies exceeding 90% for five randomly selected images.

Covalent organic frameworks (COFs) represent a novel approach for the development of anion exchange membranes (AEMs) that exhibit efficient ion transport channels due to their rigid and ordered pore structures, coupled with minimal swelling. To overcome the limitations associated with the chemical modifiability of traditional hydrazone‐bonded COFs, this study employs an imine‐based COF platform to design and synthesize a range of functionalized COF materials (COF‐Pip‐2/4/6/8), which are modified with 1‐methylpiperidinium quaternary ammonium ions via flexible alkoxy side chains. A membrane formation method utilizing trifluoroacetic acid as a solvent to induce face‐on orientation through evaporation was employed to prepare imine‐COF membranes with well‐ordered nanochannels, achieving a maximum OH ^– ion conductivity of 264.4 mS/cm. This study elucidates that the synergistic interaction between the vehicle and Grotthuss mechanisms, rather than an exclusive focus on vehicle‐mediated transport, is more effective in attaining high ion conductivity. These findings demonstrate the considerable potential of imine‐COFs in the fabrication of AEMs that offer both high stability and exceptional ion conductivity.

Functional delocalized covalent organic frameworks (COFs) show promise as active layers for the development of memristor switches and multistate functionalities. However, their potential is limited by poor electron mobility and suboptimal reaction kinetics. This study explores polarization engineering to modify the local electronic structure of the biaryl units within vinylene‐linked COFs. By implementing a conformation‐locking strategy that strategically enhances N ⁺ polarization and the redox activity of the framework, this design not only decreases the interfacial Schottky barrier but also facilitates efficient electron transfer, thereby promoting the delocalization of framework electrons, which modulates the conductive state in organic memristors. Furthermore, the polarization of ions, amplified by pyridine nitrogen nuclei and robust interlayer stacking, ensures effective counterion deintercalation and migration. The constructed Al/COF‐DIBPY/Au memristor exhibits a high analog on‐off current ratio (I _max /I _min = 15.7) under a 0.5 V drive. Utilizing these properties, the device shows great potential in performing speech emotion recognition tasks. When integrated into a convolutional neural network, it achieves a learning recognition accuracy of up to 95% in these tasks. This research offers novel insights into the construction of high‐efficiency neuromorphic computing devices based on polarization‐modulated COFs.

Organic optoelectronic synapse devices have attracted significant interest in the construction of artificial visual systems for visual information recognition and data processing. These devices can facilitate both information reception and processing within a single unit, thereby enabling bio‐inspired, system‐level efficient computation. However, conventional photosensitive elements typically respond only to the intensity of incident light and lack the capability to distinguish between specific wavelengths, which significantly restricts their application in mixed‐color information recognition. In this study, we report the development of an optoelectronic synapse device based on a covalent organic framework containing pyrazole azobenzene(COF‐TAMP). The pyrazole azobenzene moieties in COF‐TAMP undergo stepwise cis‐trans photoisomerization when exposed to light pulses ranging from 405 to 630 nm, enabling at least 20 distinct conductance states across 11 different wavelengths within the visible spectrum. Furthermore, the device exhibits remarkable optoelectronic synaptic behaviours, as demonstrated in paired‐pulse facilitation and depression experiments. Arrays of these multiwavelength‐responsive optoelectronic synapse devices offer significant potential for applications in artificial visual systems and are poised to address color distortions in modern images, thereby providing a novel approach for mixed‐color information perception.

COF-type anion exchange membranes with different pore sizes were synthesized. This study investigated the relationship between the ion transport mechanism and pore size. The highest hydroxide-ion conductivity reached 207.1 mS cm ⁻¹ .

The concurrent development of innovative photocatalysts (PCs) that achieve fast reaction rates while ensuring efficient catalyst recycling remains a significant challenge for large‐scale polymer production. Herein, we present a “two‐in‐one” strategy that combines a photoactive component with a cyclic trinuclear Cu(I)‐incorporated triangular complex as the intrinsic copper source within three imine‐linked covalent organic frameworks (COFs). As‐synthesized photoactive Cu(I)‐containing COFs demonstrated exceptional performance in aqueous photoinduced atom transfer radical polymerization (photo‐ATRP), achieving a record‐breaking turnover number (TON) of 1640 and turnover frequency (TOF) of 82 min ⁻¹ , while maintaining narrow polymer dispersity of 1.20. Such performance surpasses previously reported heterogeneous PCs designed for photo‐ATRP. Notably, the COF‐encapsulated “two‐in‐one” catalytic design endows the system with remarkable operational stability and near‐quantitative catalyst recovery. More importantly, such new COFs demonstrate outstanding process compatibility, enabling scalable production of well‐defined block copolymers in a single microreactor, without intermediate purification.

The concurrent development of innovative photocatalysts (PCs) that achieve fast reaction rates while ensuring efficient catalyst recycling remains a significant challenge for large‐scale polymer production. Herein, we present a “two‐in‐one” strategy that combines a photoactive component with a cyclic trinuclear Cu(I)‐incorporated triangular complex as the intrinsic copper source within three imine‐linked covalent organic frameworks (COFs). As‐synthesized photoactive Cu(I)‐containing COFs demonstrated exceptional performance in aqueous photoinduced atom transfer radical polymerization (photo‐ATRP), achieving a record‐breaking turnover number (TON) of 1640 and turnover frequency (TOF) of 82 min ⁻¹ , while maintaining narrow polymer dispersity of 1.20. Such performance surpasses previously reported heterogeneous PCs designed for photo‐ATRP. Notably, the COF‐encapsulated “two‐in‐one” catalytic design endows the system with remarkable operational stability and near‐quantitative catalyst recovery. More importantly, such new COFs demonstrate outstanding process compatibility, enabling scalable production of well‐defined block copolymers in a single microreactor, without intermediate purification.