Hydrogen-bonded organic framework nanocomposite, and preparation method and application thereof

Abstract

The application belongs to the field of bionic artificial synapse devices, and particularly relates to a hydrogen-bond organic framework nanocomposite material and a preparation method and application thereof. The hydrogen-bond organic framework material with a nanobelt structure is synthesized by dissolving a synthetic organic conjugated ligand in a mixed solvent under mild conditions; metal nanoparticles are prepared by a photoreduction reaction and are loaded into a two-dimensional hydrogen-bond organic assembly structure. The application develops a method for preparing a hydrogen-bond organic framework nanocomposite material, can in-situ observe the growth process of the nanomaterial by naked eyes, prevents excessive growth of the nanomaterial through color change. The nanomaterial exhibits excellent electrical signals, can realize multiple conductive state changes by means of positive and negative voltage stimulation, realizes the characteristics of short-term memory and long-term memory in combination with a designed algorithm, effectively constructs an artificial synapse simulation system, and shows high feasibility in a future neuromorphic computing application environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of bionic artificial synapse devices, and particularly relates to a hydrogen-bond organic framework nanocomposite material as well as a preparation method and application thereof. BACKGROUND

[0002] With the further development of the chip manufacturing industry, the strategy of chip size miniaturization to improve its data storage and computing capacity has reached the theoretical limit. In order to break this bottleneck, inspired by the human brain, the development of brain-like neural network computing and the establishment of artificial synapse physical models have attracted widespread attention from scientists. Compared with the traditional silicon-based semiconductor independent running storage and computing device units, the neural synapses in the human brain can realize the tasks of operation and storage in parallel, have the ability of storage and calculation integration, high-frequency information transmission and processing rate, ultra-high-density information storage capacity, and low device power consumption and other characteristics. Therefore, the development of new artificial synapse devices to construct the basic structural unit of brain-like neural computing provides an important development prospect for the next generation of machine learning, recognition, and high-density information storage technology. The current bionic memristor device based on the vertical top / bottom electrode structure shows great development potential, and by adjusting the multiple conductance states of the two-terminal device, the changes of the pre-and post-synaptic weights are simulated. So far, artificial synapse devices based on memristors have also made a series of achievements, and a variety of new memristor material systems have been developed to simulate the characteristic functions of biological synapses, such as long-term plasticity, short-term plasticity, long-term inhibition, short-term inhibition, time-dependent plasticity, and the like. However, the most widely studied memristor material is still inorganic transition metal oxide material, but its performance is limited by the tunability and flexibility of the material itself, and it cannot be applied to the current popular flexible intelligent and wearable electronic products. Therefore, it is of great significance to explore memristor materials with mechanical flexibility and synaptic characteristics.

[0003] Two-dimensional hydrogen-bond organic conjugated skeleton materials (2D-HOFs) have the advantages of low production cost, good deformation tolerance, biological compatibility, layered self-assembly structure, periodic molecular arrangement, excellent crystallinity, and have become a research hotspot in the field of two-dimensional materials, and have made great achievements in the fields of biology, energy and environment. However, due to the poor electrical conductivity and weak charge transfer ability of 2D-HOFs, their application in the field of electronics is largely limited. Therefore, by taking advantage of the high specific surface area of two-dimensional layered materials, a nanoheterojunction of 2D-HOFs and metal materials can be constructed to realize efficient charge transfer and local surface plasmon resonance effect, thereby improving the optical, electrical and chemical properties of the material and further affecting the resistance state behavior of the material. The characteristic functions of artificial synapses are simulated by means of new program algorithms, so as to realize the basic structural unit of brain-like neural computing. SUMMARY

[0004] In order to solve the problems in the prior art, the application provides a preparation method of a hydrogen-bonded organic framework nanocomposite, comprising the following steps:

[0005] S11: adding TBAPy (1,3,6,8-tetra-pyrene benzoic acid) into an organic solvent, heating and mixing to obtain a precursor solution;

[0006] S12: adding alcohol or water into the precursor solution, removing impurities, and obtaining nanoscale 2D-HOFs;

[0007] S13: under light irradiation, adding the nanoscale 2D-HOFs into a metal salt solution to react, and obtaining the hydrogen-bonded organic framework nanocomposite.

[0008] The organic-inorganic nanocomposite prepared by the method not only retains the periodicity and mechanical flexibility of the hydrogen-bonded organic framework material accumulation, but also effectively enhances the molecular charge transfer characteristics between the organic and inorganic materials, greatly improves the conductivity and resistance change characteristics of the composite material, and thus realizes a gradual current signal under voltage scanning and pulse, thereby meeting the hard requirements for developing artificial simulated synapse devices.

[0009] Meanwhile, in the step S12, the successful synthesis of the nanoscale composite material can be identified by naked eyes through sunlight and ultraviolet light irradiation, and is confirmed by dynamic light scattering, ultraviolet, fluorescence, transmission electron microscopy and other characterization means.

[0010] Preferably, in the step S11, the addition amount of TBAPy in the organic solvent is 4-6 mg / mL.

[0011] Preferably, in the step S11, the heating and mixing method is heating to 70-90 DEG C under a protective atmosphere and stirring for 12-20 h.

[0012] Preferably, in the step S12, the method for removing impurities is centrifugal separation and purification, and the nanoscale 2D-HOFs are washed with an organic solvent and alcohol for multiple times.

[0013] Preferably, the organic solvent is DMF (N,N-dimethylformamide), DMSO (dimethyl sulfoxide), 1,4 dioxane or THF (tetrahydrofuran).

[0014] Preferably, the alcohol is ethanol or isopropyl alcohol.

[0015] Preferably, the volume ratio of the organic solvent to the alcohol is 35-45:1.

[0016] Preferably, the rotation speed of the centrifugal separation is 7000-9000 r / min, and the time is 30 min.

[0017] Preferably, in the step S12, the light irradiation condition is using a simulated sunlight xenon lamp.

[0018] Preferably, the metal salt solution comprises an aqueous silver nitrate solution, an aqueous rhodium nitrate solution or an aqueous copper nitrate solution.

[0019] Preferably, in the step S13, the reaction temperature is 40-60℃, and the stirring speed is 30-50 rpm.

[0020] The application also provides a hydrogen-bonded organic framework nanocomposite prepared by the above preparation method.

[0021] The application also provides a dual-terminal structure memristor device comprising the hydrogen-bonded organic framework nanocomposite.

[0022] The application also provides a preparation method of the dual-terminal structure memristor device, comprising the following steps:

[0023] S21: mixing the hydrogen-bonded organic framework nanocomposite and the polyvinylpyrrole in a mixed solvent, and separating to obtain an upper dispersion liquid;

[0024] S22: coating the upper dispersion liquid on an indium tin oxide substrate and drying to obtain an organic functional nanofilm composite layer;

[0025] S23: evaporating a metal electrode on one side surface of the organic functional nanofilm composite layer to obtain the dual-terminal structure memristor device.

[0026] Preferably, the molecular weight of the polyvinylpyrrole is 40,000-60,000.

[0027] Preferably, the mixed solvent comprises ethanol and chlorobenzene.

[0028] Further, the volume ratio of the ethanol and chlorobenzene is 1:1-2.

[0029] Preferably, the indium tin oxide substrate is obtained by magnetron sputtering deposition, and the deposition rate is 0.1-0.3 nm / s. The thickness is 120-180 nm.

[0030] Preferably, in the step S23, the evaporation method is vacuum evaporation, and the evaporation deposition rate is 0.1-0.3 nm / s. The thickness is 80-120 nm.

[0031] Preferably, the metal electrode is a Cu electrode, an Ag electrode, an Au electrode or an Al electrode.

[0032] The application also provides an application of the dual-terminal structure memristor device in simulating the electrical behavior of a bionic artificial synapse device.

[0033] The technical solution of the present invention has the following advantages compared with the prior art:

[0034] 1. This invention discloses a visualized preparation method for hydrogen-bonded organic framework nanocomposites and its application in biomimetic artificial synapses. Based on TBAPy organic ligand molecules, which possess multidentate carboxylate ions, the molecules exhibit extremely strong non-covalent interactions, especially hydrogen bonding and π-π interactions. The synthesis method of hydrogen-bonded organic framework materials is optimized. Successful synthesis of layered nanoassemblies can be visually identified through sunlight and ultraviolet light irradiation, and confirmed by characterization techniques such as dynamic light scattering, ultraviolet light, fluorescence, and transmission electron microscopy. This method allows for real-time monitoring of the assembly process of 2D-HOFs, preventing excessive growth of nanostructures.

[0035] 2. This invention discloses a visual fabrication method for hydrogen-bonded organic framework nanocomposites and their application in biomimetic artificial synapses. Metal nanoparticles are efficiently loaded onto a two-dimensional layered pure organic conjugated assembly using a photoreduction method. This organic-inorganic nanocomposite material retains the periodicity and mechanical flexibility of hydrogen-bonded organic framework materials while effectively enhancing the molecular charge transfer characteristics between organic and inorganic materials. This significantly improves upon the inherent defects of hydrogen-bonded organic framework materials, enhances the charge transfer interaction between organic and inorganic materials, and strengthens the localized surface plasmon resonance effect. Top / bottom structure devices were fabricated, and gradient current signals were achieved under voltage scanning and pulsed conditions, meeting the stringent requirements for developing artificial neural synapse devices. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the visualized preparation method of the hydrogen-bonded organic framework nanocomposite material of the present invention and its electronic device;

[0037] Figure 2 This is a transmission electron microscope (TEM) image of the hydrogen-bonded organic framework nanocomposite material of the present invention.

[0038] Figure 3 This is an atomic force microscope (AFM) image of the hydrogen-bonded organic framework nanocomposite material.

[0039] Figure 4 The scanning electrical performance diagram of the memristor prepared by the hydrogen-bonded organic framework nanocomposite material of the present invention;

[0040] Figure 5 The image shows the repeated scanning electrical performance of the memristor prepared from the hydrogen-bonded organic framework nanocomposite material of this invention.

[0041] Figure 6 This invention relates to a method for simulating synaptic memory using memristors prepared from hydrogen-bonded organic framework nanocomposites. Detailed Implementation

[0042] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0043] Example 1

[0044] A visualized preparation method for hydrogen-bonded organic framework nanocomposites is described below:

[0045] Based on a mature synthetic procedure, the organic ligand TBAPy was generated. The organic ligand TBAPy was dissolved in anhydrous DMF solvent, and then stirred at 80°C for 16 hours under ultrasonic assistance and a nitrogen atmosphere. An excess of anhydrous ethanol solution was added, and the mixture was stirred under ultrasonic assistance. The assembly process of the two-dimensional hydrogen-bonded organic nanomaterials was monitored in real time with the naked eye and a handheld UV lamp to effectively prevent the overgrowth of nanoribbons. The size of the nanoribbon assembly was accurately analyzed using a transmission electron microscope. The synthesized suspension was further purified by centrifugation at 8000 rpm for 30 minutes. Subsequently, it was purified by washing with DMF and ethanol solvents multiple times to obtain 2D-HOFs.

[0046] Under simulated sunlight xenon lamp irradiation, 2D-HOFs were dispersed in a 55℃ silver nitrate aqueous solution and stirred at 40 rpm to prepare metal nanoparticles using a photoreduction reaction. The particle size of the nanoparticles was distributed in the range of 2-10 nanometers. They were then loaded onto a two-dimensional nanosheet structure, and the color change of the nanoassembly suspension could be observed with the naked eye, ultimately yielding a hydrogen-bonded organic framework nanocomposite material.

[0047] Example 2

[0048] A method for fabricating a two-terminal memristor device is as follows:

[0049] Hydrogen-bonded organic framework nanocomposites loaded with silver nanoparticles were dispersed in a mixed solvent of ethanol and chlorobenzene containing polyvinylpyrrole with a molecular weight of about 50,000 (volume ratio 1:2), and then spin-coated onto the surface of ITO to prepare functional nanofilms.

[0050] Under high vacuum conditions, a 100-nanometer-thick aluminum electrode was deposited on the surface of an organic functional nanofilm. The deposition rate for the first 10 nanometers was [missing information]. Subsequent deposition rate is Finally, a metal / active layer / metal dual-terminal memristor device was fabricated to simulate the electrical behavior of biomimetic artificial synaptic devices. The unit size of a single device is 0.78 mm. 2 The device, the entire device measures 2×2cm. 2 .

[0051] Example 3

[0052] The application of dual-terminal memristor devices in biomimetic artificial synapses is as follows:

[0053] Memristor devices were tested under mild conditions of 25°C and 30% humidity using a Keithley 4200-SCS semiconductor electrical and pulse testing system. DC voltages of 0 to 3V and 0 to -3V were applied, and current-voltage curves were obtained through cyclic voltage scanning stimulation. Repetitive positive and negative stimuli were used to simulate memory erasure and relearning. Further design of appropriate voltage stimulation and algorithms was undertaken to achieve short-term and long-term memory characteristics. Finally, a top / bottom structure dual-terminal memristor device was used to simulate artificial synaptic behavior.

[0054] Effect evaluation

[0055] The synthesis steps of hydrogen-bonded organic framework materials and photoreduction-loaded metal nanoparticles were described. Organic-inorganic hybrid materials were then spin-coated into organic nanofilms, and biomimetic flexible devices with top / bottom structures were fabricated, such as… Figure 1 As shown.

[0056] TEM images of the hydrogen-bonded organic framework material loaded with nanoparticles show that the nanoribbonded hydrogen-bonded material was successfully prepared and uniformly loaded with nanoparticles. The film exhibits good uniformity at the microscale, such as... Figure 2 As shown.

[0057] AFM analysis of hydrogen-bonded organic framework materials loaded with nanoparticles showed that the nanoribbons and polyvinylpyrrole underwent secondary assembly, exhibiting a uniform surface morphology and tight packing behavior, such as... Figure 3 As shown.

[0058] The electrical properties of memristors fabricated using hydrogen-bonded organic framework nanocomposites are based on the memory device's "bottom electrode / organic-inorganic hybrid HOF thin film / top electrode" structure. Under continuous voltage scanning, the device's current value exhibits a gradual change, while the resistance state continuously increases, thus displaying multiple resistance states. This is similar to the signal changes generated by the release and reception of neurotransmitters at the two ends of a synaptic neuron. Figure 4 As shown.

[0059] The performance of a device can be manipulated through electrical stimulation. Repeated positive stimulation gradually decreases the device's current level and continuously increases its resistance, exhibiting a "forgetting" process. Further negative stimulation can increase the current level, achieving a relearning process. Figure 5 As shown.

[0060] Based on electrical test results and a reasonable algorithm, this paper proposes that alternating positive and negative electrical stimulation can simulate short-term and long-term memory in artificial synaptic devices, enabling the biological applications of memristors, such as... Figure 6 As shown.

[0061] 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 method for preparing a hydrogen-bonded organic framework nanocomposite material, characterized in that, Includes the following steps: S11: Add TBAPy to an organic solvent, heat and mix to obtain a precursor solution; S12: Add alcohol or water to the precursor solution to remove impurities and obtain nano-sized 2D-HOFs; S13: Under light irradiation, nanoscale 2D-HOFs are added to a metal salt solution to react and obtain the hydrogen-bonded organic framework nanocomposite material.

2. The preparation method according to claim 1, characterized in that, In step S11, the heating and mixing method is as follows: heat to 70-90℃ under a protective atmosphere and stir for 12-20 hours.

3. The preparation method according to claim 1, characterized in that, The organic solvent is DMF, DMSO, 1,4-dioxane, or THF.

4. The preparation method according to claim 1, characterized in that, In step S13, the reaction temperature is 40-60℃.

5. The preparation method according to claim 1, characterized in that, The metal salt solution includes aqueous solutions of silver nitrate, rhodium nitrate, or copper nitrate.

6. A hydrogen-bonded organic framework nanocomposite material prepared by the preparation method according to any one of claims 1-5.

7. A two-terminal memristor device, characterized in that, Including the hydrogen-bonded organic framework nanocomposite material as described in claim 6.

8. A method for fabricating the dual-terminal memristor device according to claim 7, characterized in that, Includes the following steps: S21: After mixing hydrogen-bonded organic framework nanocomposite materials and polyvinylpyrrole in a mixed solvent, the upper dispersion is obtained by separation; S22: The upper dispersion is coated onto an indium tin oxide substrate and dried to obtain an organic functional nanofilm composite layer; S23: A metal electrode is vapor-deposited onto one side of the surface of the organic functional nanofilm composite layer coated with the upper dispersion to obtain the dual-terminal memristor device.

9. The preparation method according to claim 8, characterized in that, The mixed solvent includes ethanol and chlorobenzene.

10. The application of the dual-terminal memristor device of claim 7 in simulating the electrical behavior of biomimetic artificial synaptic devices.

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