Reconfigurable memristors based on two-dimensional covalent organic frameworks, their fabrication methods, and applications.

Abstract

This invention discloses a reconfigurable memristor based on a two-dimensional covalent organic framework, its fabrication method, and its applications. The memristor includes a bottom electrode, a covalent organic framework-based active film layer, and a top electrode stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene and [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde. By employing a covalent organic framework-based active film layer of a specific material, this memristor achieves reconfigurable switching between synaptic and pain neuron modes under different electrical control conditions within the same device. In synaptic mode, it enables stable analog conductivity modulation and multi-level storage; in pain neuron mode, it enables threshold triggering and rapid response. This provides a highly integrated, low-power device implementation scheme for end-side neuromorphic hardware systems.

Description

Technical Field

[0001] This invention belongs to the field of organic neuromorphic information storage technology, and relates to a memristor, its preparation method and application. Specifically, it relates to a reconfigurable memristor based on a covalent organic framework, its preparation method and application. Background Technology

[0002] With the rapid development of edge AI and IoT terminal technologies, massive sensors continuously generate high-dimensional, continuous, multimodal information at the data source. Edge devices need to complete real-time perception and intelligent decision-making under conditions of limited computing power, energy consumption, storage, and bandwidth, facing a prominent contradiction between "rapid growth in data scale" and "limited edge resources." Relying on centralized cloud processing introduces problems such as communication bandwidth consumption, transmission latency, and energy consumption, while also posing risks such as privacy leaks and reduced reliability. If only traditional edge processing is relied upon, the frequent data transfer overhead caused by the separation of storage and computing under the von Neumann architecture will occur, making it difficult to balance low power consumption and high real-time performance. Therefore, neuromorphic computing hardware for edge scenarios has gradually attracted widespread attention. Traditional hardware sensors need to transmit data to the cloud and call cloud neural network algorithms for calculation, which has problems such as bandwidth consumption and time delay. Edge AI deploys neural networks in edge hardware, which can complete data preprocessing at the edge with low power consumption and send the preprocessed data back to the cloud, reducing the pressure on the cloud computing center. However, the current use of traditional electronic devices to simulate neural synapses and neurons requires a large number of components and complex circuits, which is difficult to integrate on a large scale.

[0003] To reduce the variety of devices and the complexity of peripheral circuits in edge systems, and to improve integration and functional flexibility, researchers have recently proposed memristors with simple structures and biomimetic synaptic characteristics. Memristors typically employ a sandwich structure of "electrode-active layer-electrode," and their working mechanism and electrical performance are mainly determined by the active material system and ion / electron transport processes. Specifically, memristors with synaptic learning and memory modes achieve weight updates and learning and memory functions through conductivity plasticity; memristors with neuron modes achieve pulse triggering and event-driven responses through threshold switching. However, there is currently no technical solution that can controllably integrate the "synaptic learning and memory mode" and the "pain neuron mode" into a single memristor. That is, existing memristors cannot achieve the technical effect of stable, reversible, and programmable switching between the two working modes of "synapse-neuron," making it difficult to meet the comprehensive requirements of edge scenarios, such as threshold triggering, timely warning and priority response to abnormal and harmful stimuli in neuron mode, as well as the number, distinguishability and stability of multi-level conductivity states in synaptic mode. Meanwhile, common ion migration-based modulation mechanisms are prone to causing abrupt changes in conductivity and increasing randomness, further increasing the difficulty of achieving stable analog modulation and highly resolvable multi-level states.

[0004] In view of this, it is necessary to further improve the existing memristor technology. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is that there is currently no memristor that combines synaptic and neuronal modes, which makes it difficult to meet the requirements of end-side integration and to cope with the problems of conductance mutation and strong randomness. Thus, this invention proposes a reconfigurable memristor based on a two-dimensional covalent organic framework, its preparation method and application.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: The first aspect of the present invention provides a reconfigurable memristor based on a two-dimensional covalent organic framework, comprising a bottom electrode, a covalent organic framework-based active film layer, and a top electrode stacked sequentially, wherein the covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene with [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde.

[0007] Preferably, the thickness of the covalent organic framework-based active film layer is 10-60 nm.

[0008] Preferably, the covalent organic framework-based active membrane is a porous membrane, and the pore size of the pores in the porous membrane is 3-5 nm.

[0009] Preferably, the bottom electrode includes at least two spaced semiconductor electrodes or inert metal electrodes, and the top electrode includes at least two spaced metal electrodes.

[0010] Preferably, the bottom electrode is any one of ITO electrode, FTO electrode, gold electrode, and platinum electrode; the top electrode is any one of silver electrode, copper electrode, and aluminum electrode; and the dimensions of the reconfigurable memristor are: length 50-150μm and width 50-150μm.

[0011] A second aspect of the present invention provides a method for preparing the reconfigurable memristor based on a two-dimensional covalent organic framework, comprising the following steps: S1. Prepare the precursor solution by dissolving the 1,3,5-tris(4-aminophenyl)benzene organic monomer in an aqueous acetic acid solution. The resulting mixed solution contains 0.0492–0.231 wt% 1,3,5-tris(4-aminophenyl)benzene organic monomer and 1.55–7.28 wt% acetic acid. Dissolve [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde in an organic solvent. The concentration of [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde is 0.0348–0.177 wt%. S2. Preparation of covalent organic framework-based active film: The precursor solution is prepared by condensation reaction to obtain the covalent organic framework-based active film. S3. The covalent organic framework-based active film layer is transferred to the surface of a substrate with a bottom electrode to obtain a semi-finished device; S4. A top electrode is prepared on the top surface of the covalent organic framework-based active film layer to obtain the reconfigurable memristor.

[0012] Preferably, in step S2, the reaction time is 10 min to 1 h, and the covalent organic framework-based active film layer is obtained by any one of the following methods: interfacial polymerization, spin coating, spray coating, drop coating, or transfer.

[0013] Preferably, step S3 further includes heating the semi-finished device at 40-120°C for 0.5-1.5 hours.

[0014] Preferably, in step S1, the organic solvent is n-hexane or ethyl acetate.

[0015] A third aspect of the present invention provides an application of the reconfigurable memristor based on a two-dimensional covalent organic framework in neuromorphic hardware.

[0016] The technical solution of the present invention has the following advantages compared with the prior art: The reconfigurable memristor based on a two-dimensional covalent organic framework provided by this invention includes a bottom electrode, a covalent organic framework-based active film layer, and a top electrode stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene and [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde. This memristor, by employing a covalent organic framework-based active film layer of a specific material, achieves reconfigurable switching between synaptic and pain neuron modes under different electrical control conditions within the same device. In synaptic mode, it can achieve stable analog conductivity modulation and multi-level storage; in pain neuron mode, it can achieve threshold triggering and rapid response. This provides a highly integrated, low-power device implementation scheme for end-side neuromorphic hardware systems. Attached Figure Description

[0017] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of the reconfigurable memristor based on a two-dimensional covalent organic framework provided in an embodiment of the present invention; Figure 2 This is a diagram illustrating the formation mechanism of the covalent organic framework-based active film layer in a reconfigurable memristor based on a two-dimensional covalent organic framework, as provided in this embodiment of the invention. Figure 3 This is a physical image of the covalent organic framework-based active film layer of the reconfigurable memristor based on a two-dimensional covalent organic framework provided in the embodiments of the present invention during the interfacial polymerization reaction process; Figure 4 These are SEM and EDS test images of the covalent organic framework-based active film layer of the reconfigurable memristor based on a two-dimensional covalent organic framework, provided in this embodiment of the invention. Figure 5 This is an FTIR test image of the covalent organic framework-based active film layer of the reconfigurable memristor based on a two-dimensional covalent organic framework, provided in an embodiment of the present invention. Figure 6 This is an XPS test image of the covalent organic framework-based active film layer of a reconfigurable memristor based on a two-dimensional covalent organic framework, provided in an embodiment of the present invention. Figure 7 This is a BET characterization diagram of the covalent organic framework-based active film layer of the reconfigurable memristor based on a two-dimensional covalent organic framework, provided in Embodiment 3 of the present invention. Figure 8 The image shows the BET characterization of the covalent organic framework-based active film layer in the memristor provided in the comparative example. Figures 9-10 This is a basic electrical test diagram of a memristor provided by a proportional converter; Figure 11 This is a test diagram of the basic electrical performance of a memristor with single-cycle volatility provided in Embodiment 3 of the present invention; Figure 12 This is a test diagram of the basic non-volatile electrical performance of a memristor provided in Embodiment 3 of the present invention; Figure 13 This is a test diagram of the basic electrical performance of the memristor after 100 cycles of volatile operation provided in Embodiment 3 of the present invention; Figure 14 This is a statistical analysis chart of the SET voltage of a memristor after 100 volatile tests provided in Embodiment 3 of the present invention; Figure 15 This is a statistical analysis chart of the memristor's 100 non-volatile basic electrical performance tests and SET voltage provided in Embodiment 3 of the present invention; Figure 16 This is a test diagram of the threshold characteristics of the memristor pain-sensing neurons provided in Embodiment 3 of the present invention; Figure 17 This is a test diagram of the PPF characteristics of the memristor synapse provided in Embodiment 3 of the present invention; Figure 18 This is a test diagram of the characteristics of the memristor synapse with voltage pulse intensity provided in Embodiment 3 of the present invention; Figure 19 The test diagram of the memristor synapse characteristics with voltage pulse width provided in Embodiment 3 of the present invention.

[0018] The reference numerals in the figure are: 1-bottom electrode; 2-covalent organic framework-based active film layer; 3-top electrode. Detailed Implementation

[0019] Example 1 This embodiment provides a reconfigurable memristor based on a two-dimensional covalent organic framework, aiming to solve the problems of insufficient electrical performance of traditional memristors and the difficulty in achieving controllable switching of neuronal and synaptic functions within the same device. For solutions to the above problems, please refer to... Figure 1 The reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment includes, from bottom to top, a bottom electrode 1, a covalent organic framework-based active film layer 2, and a top electrode 3, which are stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde (TPDA).

[0020] The reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, by introducing a covalent organic framework-based active film layer 2 of a specific material, can achieve reconfigurable switching between synaptic mode and pain neuron mode under different electrical control conditions within the same memristor device: in synaptic mode, stable analog conductivity modulation and multi-level storage can be achieved; in pain neuron mode, threshold triggering and fast response can be achieved, providing a highly integrated and low-power device implementation scheme for end-side neuromorphic hardware systems. Furthermore, by adopting a sandwich structure of bottom electrode 1-covalent organic framework-based active film layer 2-top electrode 3, the memristor device structure is simple, easily compatible with micro-nano processes, and can achieve highly consistent devices and large-scale array integration, which is beneficial for the large-scale fabrication of end-side neuromorphic hardware.

[0021] In the reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, the covalent organic framework-based active film layer 2 plays a crucial role. Specifically, it is a porous film. In this embodiment, the thickness of the covalent organic framework-based active film layer 2 is 10-20 nm, and the pore size in the porous film is 3-5 nm. Due to its ordered porous structure, the covalent organic framework-based active film layer 2 has designable pore size and topology, as well as rich programmable functional group modification strategies. It can effectively and precisely control the ion migration channels and migration dynamics within the covalent organic framework-based active film layer 2, thereby obtaining a reconfigurable and repeatable electrical response. Furthermore, it enables controllable reconfiguration of the working mode in the same memristor device: under specific control conditions, it exhibits the threshold triggering and rapid response characteristics required by pain-sensing neurons; under another control condition, it achieves stable simulated conductance modulation characteristics of artificial synapses. This realizes the controllable switching between the two working modes of "pain-sensing neurons - artificial synapses," and can provide neuromorphic functions that combine event-triggered response and learning / memory for end-side stimuli.

[0022] In this embodiment, the reconfigurable memristor based on a two-dimensional covalent organic framework includes a bottom electrode 1 comprising at least two spaced ITO electrodes and a top electrode 3 comprising at least two spaced silver electrodes. The reconfigurable memristor utilizes the cations (silver ions Ag) in the covalent organic framework-based active film layer 2. + The migration process and the morphology of the conductive filaments (silver Ag conductive filaments) formed based on the metal electrochemical mechanism ECM enable the reconfiguration of the "pain-sensing neuron-artificial synapse" model.

[0023] As an alternative implementation, the bottom electrode 1 can also be any one of an FTO electrode (fluorine-doped tin dioxide electrode), a gold electrode, or a platinum electrode; the top electrode 3 can also be any one of a copper electrode or an aluminum electrode. Figure 1 As can be seen, the length direction of the ITO electrode is perpendicular to the length direction of the silver electrode. The overall size of the reconfigurable memristor is 50μm in length and 50μm in width, making it compact and easy to integrate.

[0024] This embodiment also provides a method for preparing the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework, the method comprising the following steps: S1. Prepare the precursor solution by dissolving 1,3,5-tris(4-aminophenyl)benzene organic monomer in an aqueous acetic acid solution. In the resulting mixed solution, the mass concentration of 1,3,5-tris(4-aminophenyl)benzene organic monomer is 0.0492 wt%, and the mass concentration of acetic acid is 1.55 wt%. Dissolve [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde in an organic solvent. In the resulting mixed solution, the mass concentration of [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde is 0.0348 wt%.

[0025] S2. Preparation of a covalent organic framework-based active film: The two precursor solutions obtained in step S1 are subjected to a condensation reaction at the interface of the two phases via interfacial polymerization to obtain a two-dimensional continuous covalent organic framework-based active film 2. In this embodiment, the reaction time is 10 min. The thickness of the covalent organic framework-based active film 2 can be controlled by parameters such as reaction time, concentration, catalytic conditions, and number of cycles. Specifically, the concentration of the precursor solution, the reaction time, and the amount of catalyst can be adjusted to regulate the covalent organic framework-based active film 2. The monomer components can affect the pore size of the porous film to meet the synergistic requirements of the trigger threshold of pain neurons and the stability of synaptic multi-level conductance states.

[0026] As an alternative implementation, the covalent organic framework-based active film layer 2 can also be prepared by spin coating, spray coating, drop coating or transfer methods.

[0027] S3. The covalent organic framework-based active film layer 2 obtained in step S2 is transferred onto a glass substrate with an ITO electrode. The substrate is then soaked and cleaned with ultrapure water and organic solvent to remove unreacted monomers and byproducts, resulting in a semi-finished device. The semi-finished device is then dried at 40°C for 1.5 hours to reduce the influence of residual solvent and adsorbed water on the consistency of the memristor, improve the adhesion between the ITO electrode and the covalent organic framework-based active film layer 2, and also improve the compactness and interface stability of the active film layer.

[0028] S4. A top electrode 3 is fabricated on the top surface of the covalent organic framework-based active film layer 2. Specifically, after attaching a mask to the top surface of the covalent organic framework-based active film layer 2, the top electrode 3 is deposited using a resistive thermal evaporator. In this embodiment, the top electrode is made of silver, and the deposition rate is 0.1 Å / s. After depositing the silver electrode, a sandwich-shaped reconfigurable memristor consisting of the bottom electrode 1, the covalent organic framework-based active film layer 2, and the top electrode 3 is obtained. As an alternative implementation, the top electrode 3 can also be fabricated by electron beam deposition, magnetron sputtering, or mechanical transfer.

[0029] This embodiment also provides an application of the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework in neuromorphic hardware. When applied, the memristor exhibits the characteristics of pain neurons with threshold triggering and rapid response in a specific control range; in another control range, it achieves stable analog conductance modulation and a sufficient number of distinguishable multi-level conductance states to simulate synaptic plasticity and weighted storage, thereby meeting the application requirements of edge devices such as real-time perception and intelligent decision-making.

[0030] Example 2 This embodiment provides a reconfigurable memristor based on a two-dimensional covalent organic framework. Please refer to [link to relevant documentation]. Figure 1 The reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment includes, from bottom to top, a bottom electrode 1, a covalent organic framework-based active film layer 2, and a top electrode 3, which are stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde (TPDA).

[0031] In the reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, the covalent organic framework-based active film layer 2 plays a crucial role. Specifically, it is a porous film. In this embodiment, the thickness of the covalent organic framework-based active film layer 2 is 50-60 nm, and the pore size in the porous film is 3-5 nm. Due to its ordered porous structure, the covalent organic framework-based active film layer 2 has designable pore size and topology, as well as rich programmable functional group modification strategies. It can effectively and precisely control the ion migration channels and migration dynamics within the covalent organic framework-based active film layer 2, thereby obtaining a reconfigurable and repeatable electrical response. Furthermore, it enables controllable reconfiguration of the working mode within the same memristor device: under specific control conditions, it exhibits the threshold triggering and rapid response characteristics required by pain-sensing neurons; under another control condition, it achieves stable simulated conductance modulation characteristics of artificial synapses. This realizes the controllable switching between the two working modes of "pain-sensing neurons - artificial synapses," and can provide neuromorphic functions that combine event-triggered response and learning / memory for end-side stimuli.

[0032] In the reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, the bottom electrode 1 includes at least two spaced-apart ITO electrodes, and the top electrode 3 includes at least two spaced-apart silver electrodes. As a variable implementation, the bottom electrode 1 can also be any one of an FTO electrode (fluorine-doped tin dioxide electrode), a gold electrode, or a platinum electrode; the top electrode 3 can also be any one of a copper electrode or an aluminum electrode. Figure 1 As can be seen, the length direction of the ITO electrode is perpendicular to the length direction of the silver electrode. The overall size of the reconfigurable memristor is 150μm in length and 150μm in width, which is small in size and easy to integrate.

[0033] This embodiment also provides a method for preparing the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework, the method comprising the following steps: S1. Prepare the precursor solution by dissolving 1,3,5-tris(4-aminophenyl)benzene organic monomer in an aqueous acetic acid solution. The resulting mixed solution contains 0.231 wt% 1,3,5-tris(4-aminophenyl)benzene organic monomer and 7.28 wt% acetic acid. Dissolve [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde in an organic solvent. The resulting mixed solution contains 0.177 wt% [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde.

[0034] S2. Preparation of a covalent organic framework-based active film: The two precursor solutions obtained in step S1 are subjected to a condensation reaction at the interface of the two phases via interfacial polymerization to obtain a two-dimensional continuous covalent organic framework-based active film 2. In this embodiment, the reaction time is 1 hour. The thickness of the covalent organic framework-based active film 2 can be controlled by parameters such as reaction time, catalytic conditions, and number of cycles, while the monomer composition can affect the pore size of the porous film to meet the synergistic requirements of the trigger threshold of pain neurons and the stability of synaptic multi-level conductance states.

[0035] As an alternative implementation, the covalent organic framework-based active film layer 2 can also be prepared by spin coating, spray coating, drop coating or transfer methods.

[0036] S3. The covalent organic framework-based active film layer 2 obtained in step S2 is transferred onto a glass substrate with an ITO electrode. The substrate is then soaked and cleaned with ultrapure water and organic solvent to remove unreacted monomers and byproducts, resulting in a semi-finished device. The semi-finished device is then dried at 120°C for 0.5 hours to reduce the influence of residual solvent and adsorbed water on the consistency of the memristor, improve the adhesion between the ITO electrode and the covalent organic framework-based active film layer 2, and also improve the compactness and interface stability of the active film layer.

[0037] S4. A top electrode 3 is fabricated on the top surface of the covalent organic framework-based active film layer 2. Specifically, after attaching a mask to the top surface of the covalent organic framework-based active film layer 2, the top electrode 3 is deposited using a resistive thermal evaporator. In this embodiment, the top electrode is made of silver, and the deposition rate is 0.1 Å / s. After depositing the silver electrode, a sandwich-shaped reconfigurable memristor consisting of the bottom electrode 1, the covalent organic framework-based active film layer 2, and the top electrode 3 is obtained. As an alternative implementation, the top electrode 3 can also be fabricated by electron beam deposition, magnetron sputtering, or mechanical transfer.

[0038] This embodiment also provides an application of the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework in neuromorphic hardware.

[0039] Example 3 This embodiment provides a reconfigurable memristor based on a two-dimensional covalent organic framework. Please refer to [link to relevant documentation]. Figure 1 The reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment includes, from bottom to top, a bottom electrode 1, a covalent organic framework-based active film layer 2, and a top electrode 3, which are stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde (TPDA).

[0040] In the reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, the covalent organic framework-based active film layer 2 plays a crucial role. Specifically, it is a porous film. In this embodiment, the thickness of the covalent organic framework-based active film layer 2 is 40-50 nm, and the pore size in the porous film is 3-5 nm. Due to its ordered porous structure, the covalent organic framework-based active film layer 2 has designable pore size and topology, as well as rich programmable functional group modification strategies. It can effectively and precisely control the ion migration channels and migration dynamics within the covalent organic framework-based active film layer 2, thereby obtaining a reconfigurable and repeatable electrical response. Furthermore, it enables controllable reconfiguration of the working mode in the same memristor device: under specific control conditions, it exhibits the threshold triggering and rapid response characteristics required by pain-sensing neurons; under another control condition, it achieves stable simulated conductance modulation characteristics of artificial synapses. This realizes the controllable switching between the two working modes of "pain-sensing neurons - artificial synapses," and can provide neuromorphic functions that combine event-triggered response and learning / memory for end-side stimuli.

[0041] In the reconfigurable memristor based on a two-dimensional covalent organic framework provided in this embodiment, the bottom electrode 1 includes at least two spaced-apart ITO electrodes, and the top electrode 3 includes at least two spaced-apart silver electrodes. As a variable implementation, the bottom electrode 1 can also be any one of an FTO electrode (fluorine-doped tin dioxide electrode), a gold electrode, or a platinum electrode; the top electrode 3 can also be any one of a copper electrode or an aluminum electrode. Figure 1 As can be seen, the length direction of the ITO electrode is perpendicular to the length direction of the silver electrode. The overall size of the reconfigurable memristor is 100μm in length and 100μm in width, which is small in size and easy to integrate.

[0042] This embodiment also provides a method for preparing the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework, the method comprising the following steps: S1. Prepare the precursor solution by dissolving 1,3,5-tris(4-aminophenyl)benzene organic monomer in an aqueous acetic acid solution. The resulting mixed solution contains 0.14 wt% 1,3,5-tris(4-aminophenyl)benzene organic monomer and 4.25 wt% acetic acid. Dissolve [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde in an organic solvent. The resulting mixed solution contains 0.105 wt% [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde.

[0043] S2. Preparation of a covalent organic framework-based active film: The two precursor solutions obtained in step S1 are subjected to a condensation reaction at the interface of the two phases via interfacial polymerization to obtain a two-dimensional continuous covalent organic framework-based active film 2. In this embodiment, the reaction time is 30 min. The thickness of the covalent organic framework-based active film 2 can be controlled by parameters such as reaction time, monomer concentration, catalytic conditions, and number of cycles. The monomer composition can affect the pore size of the porous film to meet the synergistic requirements of the trigger threshold of pain neurons and the stability of synaptic multi-level conductance states.

[0044] As an alternative implementation, the covalent organic framework-based active film layer 2 can also be prepared by spin coating, spray coating, drop coating or transfer methods.

[0045] S3. The covalent organic framework-based active film layer 2 obtained in step S2 is transferred onto a glass substrate with an ITO electrode. The substrate is then soaked and cleaned with ultrapure water and organic solvent to remove unreacted monomers and byproducts, resulting in a semi-finished device. The semi-finished device is then dried at 80°C for 1 hour to reduce the influence of residual solvent and adsorbed water on the consistency of the memristor, improve the adhesion between the ITO electrode and the covalent organic framework-based active film layer 2, and also improve the compactness and interface stability of the active film layer.

[0046] S4. A top electrode 3 is fabricated on the top surface of the covalent organic framework-based active film layer 2. Specifically, after attaching a mask to the top surface of the covalent organic framework-based active film layer 2, the top electrode 3 is deposited using a resistive thermal evaporator. In this embodiment, the top electrode is made of silver, and the deposition rate is 0.1 Å / s. After depositing the silver electrode, a sandwich-shaped reconfigurable memristor consisting of the bottom electrode 1, the covalent organic framework-based active film layer 2, and the top electrode 3 is obtained. As an alternative implementation, the top electrode 3 can also be fabricated by electron beam deposition, magnetron sputtering, or mechanical transfer.

[0047] This embodiment also provides an application of the above-mentioned reconfigurable memristor based on a two-dimensional covalent organic framework in neuromorphic hardware.

[0048] Comparative Example This comparative example provides a memristor whose structure and preparation method are basically the same as those in Example 3, except that the covalent organic framework-based active film is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene (TAPB) and terephthalaldehyde (TA).

[0049] Test case 1. Characterization of chemical properties (1) Morphology of the covalent organic framework-based active film layer of the memristor provided in Example 3 of this application: The formation mechanism of the covalent organic framework-based active film layer in the memristor provided in Embodiment 3 of this application is as follows: Figure 2As shown in the figure, the precursor solution undergoes interfacial polymerization at the oil and water phase interface to form a porous film. A photograph of the resulting film is shown below. Figure 3 As shown in the figure, the active film layer was successfully synthesized.

[0050] The scanning electron microscope (SEM) image and EDS spectrum of the covalent organic framework-based active film layer of the memristor provided in Embodiment 3 of this application are as follows: Figure 4 As shown, the SEM test results indicate that a thin film was formed and the film surface has no obvious impurities or defects. The EDS energy spectrum shows the scans of C, N, and Si elements, respectively. The test results show that the elements in the film are uniformly distributed. In addition, Si element scanning was used because the substrate is Si, and the Si distribution in the covered part of the film is less, which proves that the film synthesis was successful and dense, and that the underlying Si was covered.

[0051] (2) Testing the chemical composition of the covalent organic framework-based active film layer of the memristor provided in Example 3 of this application: The Fourier transform infrared (FTIR) spectrum and X-ray photoelectron spectroscopy (XPS) spectrum of the covalent organic framework-based active film layer of the memristor provided in Embodiment 3 of this application are as follows: Figures 5-6 As shown, the absorption peaks in the FTIR spectrum confirm the chemical structure of the covalent organic framework-based active film, and the XPS spectrum confirms the chemical structure of the covalent organic framework-based active film through the chemical valence state and bonding mode of the elements.

[0052] (3) Testing the pore structure of the covalent organic framework-based active membrane: The pore structure of the covalent organic framework-based active film layer in the memristor provided in Example 3 of this application and the covalent organic framework-based active film layer in the memristor provided in the comparative example were tested using the surface area ratio (BET) method. For ease of distinction, the memristor provided in Example 3 of this application is named COF-TAPB-TPDA device, and the memristor provided in the comparative example is named COF-TAPB-TA device. The BET characterization diagrams of the covalent organic framework-based active film layer in the COF-TAPB-TPDA device and the COF-TAPB-TA device are shown below. Figures 7-8 As shown.

[0053] As can be seen from the figure, the pore size of the covalent organic framework-based active film in the COF-TAPB-TPDA device provided in Example 3 is larger than that in the covalent organic framework-based active film in the COF-TAPB-TA device provided in the comparative example. This is due to the different types of organic monomers in the precursor solution; different precursors form different COF films through condensation reactions, as confirmed by BET characterization results.

[0054] Studies have shown that smaller aperture COFs severely restrict the growth and stabilization of conductive filaments, causing the device to exhibit only volatile threshold switching characteristics, corresponding to the pain-sensing neuron mode. In contrast, larger aperture COFs provide a relatively spacious growth environment for the conductive filaments, facilitating their stable formation and morphological control, thus endowing the device with non-volatile storage characteristics. Based on the structural advantages of large-aperture COFs, the device achieved stable analog conductance modulation and multi-level conductance states in synaptic mode, and precise threshold triggering and rapid response in pain-sensing neuron mode. This significantly improved the consistency and repeatability of the device's response, ultimately successfully achieving reconfigurable switching between pain-sensing neuron mode and artificial synaptic mode within the same device.

[0055] 2. The memristor provided in Example 3 and the memristor provided in the comparative example were subjected to electrical tests using a semiconductor parameter analyzer.

[0056] The basic electrical performance test results of the COF-TAPB-TA devices provided in the comparative example are as follows: Figures 9-10 As shown. The basic electrical performance test results of the COF-TAPB-TPDA device provided in Embodiment 3 of this application are as follows. Figures 11-15 As shown, where, Figures 11-12 These are the basic electrical performance test diagrams of the memristor's single-cycle volatile and non-volatile characteristics provided in Example 3; Figure 13 This is a basic electrical performance test chart of the memristor after 100 cycles of volatile degradation, provided in Example 3. Figure 14 This is a statistical analysis chart of the SET voltage after 100 volatile tests; Figure 15 This is a statistical analysis chart of the memristor's basic non-volatile electrical performance test and SET voltage after 100 cycles, provided in Example 3.

[0057] Test results show that, due to the small pore size of the covalent organic framework active film in the COF-TAPB-TA device, regardless of the electrical test conditions, the conductive wires (silver conductive wires) formed based on the metal electrochemical mechanism (ECM) can only form thin, unstable conductive wires due to the spatial geometric confinement effect of the COF formed by the small-pore TA monomers. These wires break rapidly, leading to volatility. Furthermore, due to the small pore size, conductive wire formation is difficult, requiring a relatively high voltage to be applied during the initial device test (i.e., the forming process). Subsequent tests, due to residual broken conductive wires, require a lower formation voltage than the forming process.

[0058] As can be seen from the figure, this memristor device can operate in both volatile neuron and non-volatile synapse modes. This is because the covalent organic framework active film layer of the COF-TAPB-TPDA device has a large pore size and redundant space. During the test, using smaller electrical test conditions, the conductive wire (silver conductive wire) formed based on the metal electrochemical mechanism ECM forms a thin, unstable conductive wire that breaks rapidly, leading to volatility. Conversely, using larger electrical test conditions, the conductive wire (silver conductive wire) formed based on the metal electrochemical mechanism ECM forms a thicker, stable conductive wire that does not break rapidly, leading to non-volatility. This results in the technical effect of dual-mode controllable reconfiguration.

[0059] As described above, the current of a memristor device can be measured by applying a voltage pulse, thereby characterizing its conductance state and its evolution under electrical stimulation, and further studying its neuromorphic functional simulation performance. The memristor device provided in this application embodiment can achieve reconfigurable switching between two working modes under electrical control conditions: artificial synapse mode and pain-sensing neuron mode.

[0060] Specifically, from a biological mechanism perspective, a biological synapse can be abstracted into three parts: the presynaptic membrane, the synaptic cleft, and the postsynaptic membrane. The presynaptic membrane releases neurotransmitters, which cross the synaptic cleft and act on the postsynaptic membrane, triggering excitatory / inhibitory postsynaptic currents (EPSC / IPSC). Correspondingly, in the synaptic operating mode of this device, an applied pulse stimulus can be equivalent to a presynaptic input signal, the carrier / ion transport and interface modulation process triggered by the stimulus can be equivalent to the process of "neurotransmitters crossing the synaptic cleft and acting on the postsynaptic membrane," and the reversible modulation of the device current can be equivalent to the postsynaptic current response. By adjusting parameters such as pulse amplitude, width, interval, and number of pulses, the device can exhibit typical synaptic behaviors such as short-term and long-term plasticity, and achieve multi-level, stable, and distinguishable conductance states for simulating the continuous adjustment and storage of synaptic weights.

[0061] On the other hand, a key characteristic of pain-sensing neurons lies in their threshold triggering and rapid response to potentially harmful stimuli; that is, they generate significant output and exhibit preferential response characteristics when the stimulus intensity exceeds a threshold. Correspondingly, in the pain neuron operating mode of this device, the device exhibits obvious threshold switching / triggering behavior: when the applied electrical stimulus is below the threshold, the output is weak or there is no response; when the stimulus exceeds the threshold, the output current rapidly increases, achieving rapid identification and alarm-like response to "harmful stimuli." By setting different electrical control conditions (e.g., limiting the current to a compliant current, controlling the pulse energy / amplitude range, or equivalently controlling the ion migration dynamics operating range), controllable switching between the pain neuron mode and the synaptic mode can be achieved in the same device, thereby forming a "neuron-synapse" reconfigurable neuromorphic unit.

[0062] Furthermore, the test results of the threshold characteristics of the pain-sensing neurons in the COF-TAPB-TPDA device provided in Embodiment 3 of this application are as follows: Figure 16 As shown, in the pain neuron mode, threshold triggering and rapid response behavior can be characterized by applying pulses of different intensities, and key parameters such as threshold, response delay, and recovery characteristics can be further extracted. By changing the electrical control conditions (e.g., compliant current, stimulation energy range, or equivalent operating point), controllable switching between the pain neuron mode and the synaptic mode can be achieved in the same device, thus demonstrating the reconfigurable nature of the device.

[0063] The synaptic mode test results of the COF-TAPB-TPDA device provided in Embodiment 3 of this application are as follows: Figures 17-19 As shown, where, Figure 17 The diagram shows the synaptic PPF characteristics of the COF-TAPB-TPDA device. Figure 18 The graph shows the synaptic response of the COF-TAPB-TPDA device to voltage pulse intensity. Figure 19 This image shows the synaptic pulse width characteristic test results of a COF-TAPB-TPDA device. In synaptic mode, by applying a pulse sequence and recording the current response at a fixed readout voltage, a postsynaptic current characterization similar to that of an EPSC / IPSC can be obtained. Further analysis of the device's dependence on pulse amplitude, width, interval, and number of pulses allows verification of short-term enhancement / suppression, paired pulse facilitation (PPF), learn-forget characteristics, and multi-level conductance state modulation capabilities. The principle is that as the pulse amplitude, width, interval, and number of pulses increase sequentially, the conductive filament correspondingly thickens, resulting in more conductive paths, lower resistance, higher conductance, and greater current.

[0064] The test results above show that the COF-TAPB-TA device provided in the comparative example cannot achieve controllable switching between the two working modes of pain-sensing neurons and artificial synapses. However, the COF-TAPB-TPDA device provided in this application embodiment can achieve controllable switching between the two working modes of pain-sensing neurons and artificial synapses within the same device: in a specific control range, it can exhibit the characteristics of pain neurons with threshold triggering and rapid response; in another control range, it can achieve stable analog conductance modulation and a sufficient number of distinguishable multi-level conductance states to simulate synaptic plasticity and weight storage.

[0065] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A reconfigurable memristor based on a two-dimensional covalent organic framework, characterized in that, The device comprises a bottom electrode, a covalent organic framework-based active film layer, and a top electrode stacked sequentially. The covalent organic framework-based active film layer is prepared by condensation of 1,3,5-tris(4-aminophenyl)benzene with [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde. The reconfigurable memristor based on the two-dimensional covalent organic framework is prepared by the following method: S1. Prepare the precursor solution by dissolving the 1,3,5-tris(4-aminophenyl)benzene organic monomer in an aqueous acetic acid solution. The resulting mixed solution contains 0.0492–0.231 wt% 1,3,5-tris(4-aminophenyl)benzene organic monomer and 1.55–7.28 wt% acetic acid. Dissolve [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde in an organic solvent. The concentration of [1,1':4',1''-terphenyl]-4,4''-dicarboxaldehyde is 0.0348–0.177 wt%. S2. Preparation of covalent organic framework-based active film: The precursor solution is prepared by condensation reaction to obtain the covalent organic framework-based active film. S3. The covalent organic framework-based active film layer is transferred to the surface of a substrate with a bottom electrode to obtain a semi-finished device. The semi-finished device is heated at 40-120°C for 0.5-1.5 hours. S4. A top electrode is fabricated on the top surface of the covalent organic framework-based active film layer to obtain the reconfigurable memristor. The dimensions of the reconfigurable memristor are: length 50-150 μm and width 50-150 μm. The reconfigurable memristor is applied to neuromorphic hardware, which realizes reconfigurable switching between synaptic mode and pain neuron mode under different electrical control conditions. In synaptic mode, it realizes stable analog conductivity modulation and multi-level storage, and in pain neuron mode, it realizes threshold triggering and fast response.

2. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 1, characterized in that, The thickness of the covalent organic framework-based active film is 10-60 nm.

3. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 1 or 2, characterized in that, The covalent organic framework-based active membrane is a porous membrane, and the pore size of the pores in the porous membrane is 3-5 nm.

4. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 3, characterized in that, The bottom electrode includes at least two spaced semiconductor electrodes or inert metal electrodes, and the top electrode includes at least two spaced metal electrodes.

5. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 4, characterized in that, The bottom electrode is any one of ITO electrode, FTO electrode, gold electrode, and platinum electrode; the top electrode is any one of silver electrode, copper electrode, and aluminum electrode.

6. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 5, characterized in that, In step S2, the reaction time is 10 min to 1 h, and the covalent organic framework-based active film layer is obtained by any of the following methods: interfacial polymerization, spin coating, spray coating, drop coating, or transfer.

7. The reconfigurable memristor based on a two-dimensional covalent organic framework according to claim 6, characterized in that, In step S1, the organic solvent is n-hexane or ethyl acetate.

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