A homometallic molybdate hybrid resistive random access memory material based on tetraphenylstyrene molecules and a preparation method and application thereof

Abstract

The application discloses a homopolymolybdate hybrid resistive random access memory material based on a tetraphenylstyrene molecule and a preparation method and application thereof. The preparation method comprises the following steps: dissolving a mixture of 0.05 mmol of homopolymolybdate and 0.1 mmol of the tetraphenylstyrene molecule in 10 mL of water, stirring for 2 hours, adjusting the pH to 5.0 by using HCl to obtain a mixed solution; moving the mixed solution into a 25 mL stainless steel reaction kettle lined with polytetrafluoroethylene, reacting at 160 DEG C for 3 days, and obtaining a colorless block crystal after cooling; and after filtration, washing and drying, the homopolymolybdate hybrid resistive random access memory material based on the tetraphenylstyrene molecule is obtained. The method is simple and easy to operate, raw materials are easy to obtain, and the method is easy to realize. No harmful product is generated in the preparation process, and the method is an environment-friendly green synthesis. A multi-level controllable memory storage material is prepared, and the material can be applied to a multi-level memristor.

Description

Technical Field

[0001] This invention belongs to the field of storage materials technology, specifically relating to a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules, its preparation method, and its application. Background Technology

[0002] The era of explosive growth in information volume places higher demands on next-generation high-density data storage, and multilevel memory is the most practical method to break through the von Neumann bottleneck. To achieve high-density data storage, research into novel materials is crucial. Because organic-inorganic hybrid materials possess tunable structures, their resistive switching behavior can be significantly enhanced through subtle structural modifications and designs. However, they also have limitations; the fabrication process often faces problems such as poor device morphology, poor reproducibility, and complex synthesis processes. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules, along with its preparation method and applications. This method utilizes 4-[4-(1,2,2-triphenylvinyl)phenyl]pyridine and [(n-C4H9)4N]4(Mo8O) 26 Using tetraphenylethylene-based molecules as raw materials, the hot solvent method is simple and easy to operate, the raw materials are readily available and easy to implement, and there are no harmful byproducts in the preparation process, making it an environmentally friendly green synthesis. The resulting polymolybdate hybrid resistive switching memory material is a multi-level controllable memory storage material that can be applied in multi-level memristors.

[0004] The present invention adopts the following technical solution:

[0005] A method for preparing a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is disclosed. The specific preparation process is as follows: 0.05 mmol of a mixture of polymolybdate and 0.1 mmol of tetraphenylethylene molecules are dissolved in 10 mL of water and stirred for 2 h. The pH is adjusted to 5.0 with HCl to obtain a mixed solution. The mixed solution is then transferred to a 25 mL stainless steel reactor lined with polytetrafluoroethylene and reacted at 160 °C for 3 days. After cooling, colorless blocky crystals are obtained. After filtration, washing, and drying, the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is obtained.

[0006] Preferably, the isopolymolybdic acid is [(n-C4H9)4N]4(Mo8O) 26 The tetraphenylethylene molecule is 4-[4-(1,2,2-triphenylvinyl)phenyl]pyridine.

[0007] Preferably, the cooling process involves reducing the temperature to 30°C over a period of two days.

[0008] Preferably, the washing reagent is distilled water; the drying is performed under vacuum at 40°C.

[0009] A polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is prepared using the same preparation method for polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules.

[0010] An application of a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules, wherein the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is used as a resistive switching memory layer in a multi-level memristor.

[0011] Preferably, the multi-stage memristor has a sandwich structure consisting of a bottom electrode, a resistive switching storage layer, and a top electrode; the bottom electrode is a fluorine-doped indium tin oxide conductive material; and the top electrode is an inert metal material.

[0012] By adopting the above technical solution, the present invention has the following advantages compared with the prior art:

[0013] 1. This invention is based on aggregation-inducing molecules (AIE) with aggregation-induced current effect and polyoxometalate molecules (POM) with redox properties and high temperature resistance to prepare a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules. It is a multi-level switchable memory material.

[0014] 2. This invention uses 4-[4-(1,2,2-triphenylvinyl)phenyl]pyridine (or TPE-mono-Py) and [(n-C4H9)4N]4(Mo8O) 26 Using 1,000 ions as raw materials, the hot solvent method is simple and easy to operate. The raw materials are readily available and easy to implement. Moreover, there are no harmful byproducts in the preparation process, making it an environmentally friendly green synthesis. The synthesis cost is low, and the film-forming properties are excellent. It is suitable for large-scale industrial production and has good application prospects.

[0015] 3. The tetraphenylethylene-based polymolybdate hybrid resistive switching memory material of the present invention can form a uniform and dense thin film on the substrate, exhibiting excellent multi-level memory storage performance under both room temperature and high temperature conditions, and has good cycle fatigue resistance. The FTO / tetraphenylethylene-based polymolybdate hybrid resistive switching memory material / Ag device exhibits typical non-volatile WORM ternary memory characteristics at room temperature, with an ON2 / ON1 / OFF state current ratio of 10. 6.7 :10 4.3 :1, V Set1 / V Set2The voltage is 0.99 / 1.23V, and the ternary yield is 70%. At 240°C, the device exhibits typical non-volatile WORM ternary memory characteristics, with an ON2 / ON1 / OFF state current ratio of 10. 5.0 :10 3.2 :1, V Set1 / V Set2 The voltages were 0.89 / 1.47V. After undergoing a 240°C to room temperature test, the device still exhibited typical ternary memory characteristics, verifying the good device stability and providing a new strategy for fabricating high-temperature resistant, high-performance memories. Attached Figure Description

[0016] Figure 1 This is a crystal structure diagram of the isopolymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules of the present invention.

[0017] Figure 2 This is an X-ray powder diffraction pattern of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules according to the present invention.

[0018] Figure 3 The infrared spectrum of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules of the present invention is shown.

[0019] Figure 4 This is the liquid UV-Vis diffuse reflectance spectrum of the tetraphenylethylene-based polymolybdate hybrid resistive switching memory material of the present invention.

[0020] Figure 5 Thermogravimetric analysis (TGA) of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules of the present invention.

[0021] Figure 6 This is a schematic diagram illustrating the fabrication process of the polymolybdate hybrid resistive switching memory device based on tetraphenylethylene molecules according to the present invention.

[0022] Figure 7 This is a test curve of the IV characteristic of the tetraphenylethylene-based polymolybdate hybrid resistive switching memory device at room temperature.

[0023] Figure 8 This is a graph showing the IV characteristic curve of the tetraphenylethylene-based polymolybdate hybrid resistive switching memory device at 240°C.

[0024] Figure 9 This is a test graph showing the IV characteristic curves of the polymolybdate hybrid resistive switching memory device based on tetraphenylethylene molecules of the present invention from high temperature to room temperature. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] See Figures 1 to 9 .

[0027] Preparation of a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules:

[0028] [(n-C4H9)4N]4(Mo8O 26 A mixture of 0.079 g (0.05 mmol) of phenylpyridine (4-(4-(1,2,2-triphenylvinyl)phenyl)pyridine (0.041 g, 0.1 mmol) was dissolved in 10 mL of water and stirred for 2 h. The pH was adjusted to 5.0 with HCl (1 mol / L). The resulting mixture was transferred to a 25 mL stainless steel reactor lined with polytetrafluoroethylene and kept at 160 °C for 3 days, followed by a 2-day cooling process to 30 °C. Colorless blocky crystals were obtained, filtered, washed with distilled water, and dried under vacuum at 40 °C to obtain 0.0243 g of the product, which is the isopolymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules.

[0029] First, FTO conductive glass was placed in a beaker and acetone, ethanol, and deionized water were added sequentially. Each layer was sonicated for 20 minutes. The FTO (20mm × 20mm) was then dried in an oven at 100℃ for 30 minutes. Next, 5mg of the test crystal was added to 10mL of DMF, and sonicated for 2 hours to form a clear solution. 0.2mL of this solution was then dropped onto the conductive surface of the conductive glass and spin-coated at 1000rpm, 3000rpm, and 5000rpm for 10 seconds each. The solution was then annealed at 60℃ for 3 hours to remove the DMF solution. Finally, 0.5mg / mL of the solution was used… -1 The silver electrodes on the top of all devices were prepared by passing a high concentration of Ag nanowire suspension through a mask with a small circular hole of about 0.1 cm in diameter for 1 min. The prepared devices were then dried in an oven at 60 °C for 30 min to improve their adhesion.

[0030] Performance testing:

[0031] 1. The crystal structure of polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules is as follows: Figure 1 As shown. From Figure 1 It can be seen that the structural analysis of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules shows that the compound consists of two parts: one (Mo8O) 26 )4- Anions, four (TPE-mono-Py) + It consists of a cation and two free water molecules. The molybdate anion forms a zero-dimensional molecule with four organic cations through electrostatic attraction, belonging to the triclinic crystal system, space group P-1. The molybdate anion has C 2h It is symmetrical and consists of eight MoO6 octahedrons sharing oxygen vertices. Mo is located at the center of the octahedron and is connected to four bridging oxygen atoms, one terminal oxygen atom, and one central oxygen atom. The lengths are within the normal range. The dihedral angles between the two organic cationic pyridine rings and their adjacent benzene rings in the asymmetric unit are 29.34° and 28.76°, respectively, indicating a certain degree of twisting between the rings (e.g., ...). Figure 1 Part a). Free water molecules in the crystal bind to two (Mo8O) molecules through hydrogen bonds. 26 ) 4- Anion-linked, (TPE-mono-Py) + The pyridine ring of the cation bonds to a free water molecule and a (Mo8O) molecule via hydrogen bonding. 26 ) 4- Anions connected (e.g.) Figure 1 Part b). (TPE-mono-Py) + The interaction between the benzene rings of the cations via CH···π increases the structural stability of the organic moiety. (Mo8O) 26 ) 4- Anions interact with (TPE-mono-Py) through the anion-π interaction. + The attraction of the pyridine ring in the cation further increases the stability of the overall structure (e.g., Figure 1 (Part d). Due to the presence of hydrogen bonds in compound 2-1, the interaction between CH···π and the anion···π (e.g. Figure 1 (Part c) The overall architecture stability has been enhanced. A 3D packing diagram of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is shown below. Figure 1 As shown in section e. Table 1 shows the crystallographic data and structural refinement parameters of polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules. Table 2 shows the bond lengths and bond angles of hydrogen bonds in polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules. Table 3 shows the CH···π interaction table for polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules. Table 4 shows the anion···π interaction table for polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules.

[0032] Table 1: Crystallographic data and structural refinement parameters of polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules

[0033]

[0034]

[0035] Table 2: Bond lengths and bond angles of hydrogen bonds in polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules.

[0036]

[0037]

[0038] Table 3: CH···π Interactions of Tetraphenylene-based Polymolybdate Hybrid Resistive Switching Memory Materials

[0039]

[0040] Symmetry code: a -x+1, -y, -z; b -1+x,y,z; c -x,1-y,1-z

[0041] Table 4: Anion-π Interactions of Tetraphenylene-based Polymolybdate Hybrid Resistive Switching Memory Materials

[0042]

[0043] Symmetry code: a 1-x, 2-y, 1-z

[0044] 2. X-ray powder diffraction analysis

[0045] like Figure 2 As shown, the X-ray powder diffraction pattern of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is shown. The experimental and fitted values ​​are in good agreement, indicating that the compound is a pure phase. The differences in intensity of some diffraction peaks are due to the fineness and anisotropy of the crystal grinding.

[0046] 3. Infrared spectral characterization:

[0047] like Figure 3 The image shows the infrared spectrum of a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene-based molecules. Since the organic portion of all three compounds is predominantly tetraphenylethylene with pyridine or imidazole substituents, and the inorganic portion is a molybdate anion, the infrared spectra are located in the 1500-1200 cm⁻¹ range. -1 The stretching vibration of the CN bond is located at 1000-500 cm⁻¹, corresponding to the CN bond in the organic pyridine ring. -1The vibrational peaks in the region are attributed to the Mo-O asymmetric stretching vibration of the molybdate anion. Table 5 shows the main infrared peak positions and their assignments for polymolybdate hybrid resistive switching memory materials based on tetraphenylethylene molecules.

[0048] Table 5: Main infrared spectral characteristic absorption peaks and their assignments for tetraphenylethylene-based polymolybdate hybrid resistive switching memory materials

[0049]

[0050] 4. Liquid ultraviolet diffuse reflectance spectroscopy analysis

[0051] Liquid UV-Vis diffuse reflectance spectra of tetraphenylethylene-based polymolybdate hybrid resistive switching memory materials were measured in the wavelength range of 200-800 nm. Figure 4 As shown. Observation revealed that the absorption peaks of the three compounds in the 250-320 nm range are attributed to the π-π bonds of tetraphenylethylene. * The strong absorption peak near 340 nm is attributed to the O→Mo charge transition.

[0052] 5. Thermogravimetric analysis

[0053] like Figure 5 As shown, thermogravimetric analysis (TGA) was performed on three compounds under a nitrogen atmosphere at a heating rate of 10 °C / min, within a temperature range of 30–800 °C. The results are as follows. Figure 2-8 As shown, the crystal structure of the polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules can be maintained up to 270℃. In the first stage of heating (30-130℃), the weight loss ratio is 1.00% (theoretical value is 1.26%), which is attributed to the loss of free water in the crystal. In the second stage (130-275℃), the weight loss ratio is 3.93% (theoretical value is 4.02%), which is attributed to the loss of the pyridine ring on the organic ligand. In the third stage (275-500℃), the weight loss ratio is 54.16% (theoretical value is 58.46%), which is mainly attributed to the loss of organic matter in the compound.

[0054] 6. Multi-level controllable memory storage performance test:

[0055] The IV characteristic curves of FTO / Ag devices based on tetraphenylethylene-based polymolybdate hybrid resistive switching memory materials were tested in a KEYSIGHT-B2901A single-channel semiconductor parameter tester.

[0056] like Figure 7The image shows the electrical properties of FTO / Ag hybrid resistive switching memory based on tetraphenylethylene molecules at room temperature. First, the current-voltage (IV) characteristic curves of the FTO / Ag memory device were tested at a 0.5A limiting current (CC) from 0V to 5V to -5V. Figure 7 As can be seen in section a, when a positive scan voltage (from 0 to 5.0V) is applied, the device is initially in a low conductivity ("0" or "off") state. However, when the applied positive voltage is further increased to 0.99V, the device first transitions from a low conductivity (~10V) state. -8.5 A, "Off" state) transitions to medium conductivity (~10) -4.1 A, “ON1” state). Later, as the applied positive voltage is further increased to 1.23V, the “ON1” state switches to a high conductivity state (~10). -1.7 A). This process is equivalent to the "write" process in digital storage. During subsequent scans of the applied voltage (5-0V and 0-5V), the device remains stable in a high conductivity state; this step is equivalent to the "read" process in digital storage. The corresponding current ratio for ON2, ON1, and OFF states is 10. 6.7 :10 4.3 :1, higher than the switching current ratio of organic devices, such as imine polymers: ITO / 2DP / Ag (ON2 / ON1 / OFF=10) 3 :10:1), All-inorganic graphene oxide devices: ITO / GO-based / Ni (ON2 / ON1 / OFF=10 3 :10 2 :1). The data results show that the device exhibits typical non-volatile WORM ternary memory characteristics. From Figure 7 As can be seen from section b, under constant voltages of 0.01V, 1.37V, and 1.97V, ON2, ON1, and OFF exhibit good stability without significant shift. Figure 7 Part C of the V-shaped data from 10 rounds of measurements Set1 and V Set2 Statistical analysis and the creation of a bar chart based on distribution characteristics show that the device exhibits good repeatability in ternary memory performance. Additionally, as... Figure 7 The section d shows how a waterfall plot of 10 random IV characteristic curves is used to verify the ternary memory stability of the device. Figure 7Part e shows the stability of the memory device further verified by plotting the current distribution over 100 rounds at 0.01V in both high and low resistance states. Furthermore, statistical analysis of the 100 rounds of IV characteristic curves revealed a ternary yield of 70%, higher than the yields of most other ternary memory devices, such as the covalent organic polymer ITO / Py-COPs / Ag (55%) and the inorganic metal ion organic coordination polymer ITO / Pd-DABDT / Al (56%). Retention time is a key parameter for device stability, such as… Figure 7 As shown in section f, under a constant voltage of 0.1V, the device remains in the "OFF", "ON1", and "ON2" states for 3 × 10⁻⁶ seconds. 3 s did not change significantly.

[0057] like Figure 8 The image shows the electrical characteristics of FTO / Ag hybrid resistive switching memory material based on tetraphenylethylene molecules at 240℃. The current-voltage (IV) characteristic curves of the FTO / Ag memory device were tested under a 0.5A limiting current (CC). Figure 8 As can be seen in section a, when a positive scan voltage (from 0 to 5.0V) is applied, the device is initially in a low conductivity ("0" or "off") state. However, when the applied positive voltage is further increased to 0.89V, the device first transitions from a low conductivity (~10V) state. -6.8 A, "Off" state) transitions to medium conductivity (~10) -3.6 A, “ON1” state). Later, as the applied positive voltage is further increased to 1.47V, the “ON1” state switches to a high conductivity state (~10). -1.8 A). This process is equivalent to the "write" process in digital storage. During the subsequent 5-0V and 0-5V scans, the device remains stable in a high conductivity state; this step is equivalent to the "read" process in digital storage. The corresponding current ratio for ON2, ON1, and OFF states is 10. 5.0 :10 3.2 :1, representing a device exhibiting typical non-volatile WORM ternary memory characteristics. From Figure 8 As can be seen from section b, under constant voltages of 0.01V, 1.14V, and 1.89V, ON2, ON1, and OFF exhibit good stability without significant shift. Figure 8 Part C analyzes the V-shaped data from 10 rounds of measurements. Set1 and V Set2 The statistics were analyzed and a bar chart was created based on the distribution characteristics. The results show that the ternary memory performance of the device has good repeatability. Additionally, as... Figure 8The section d shows how a waterfall plot of 10 random IV characteristic curves is used to verify the ternary memory stability of the device. Figure 8 The stability of the memory device was further verified by taking 100 rounds of current distribution in high and low resistance states at a voltage of 0.01V, as shown in section e. This shows that the device can operate stably at 240℃, which is much higher than the temperature tolerance of other materials, such as organic-inorganic halide perovskite: Ag / BA2PbI4 / Pt / Ti / SiO2 / Si (87℃) and organic polymer: Al / SWNT+PS-b-PPP / Au (100℃). Figure 8 The device shown in section f can achieve a maximum current switching ratio of 10 at a high temperature of 240℃. 5 .

[0058] like Figure 9 The image shows the electrical characteristics of FTO / Ag hybrid resistive switching memory material based on tetraphenylethylene molecules at high temperature and then back to room temperature. Current-voltage (IV) characteristic curves of the FTO / Ag memory device were tested under a 0.5A limiting current (CC). From... Figure 9 It can be observed that the device exhibits typical ternary storage characteristics at 240℃. When the ambient temperature is restored to room temperature, the device still exhibits typical ternary storage characteristics. This was repeated for three cycles to verify the high-temperature storage stability of the device. It was found that the device has good high-temperature resistance and can withstand a high temperature of 240℃.

[0059] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules, characterized in that, The specific preparation process is as follows: 0.05 mmol of isopolymolybdic acid and 0.1 mmol of tetraphenylethylene molecules are dissolved in 10 mL of water, stirred for 2 h, and the pH is adjusted to 5.0 with HCl to obtain a mixed solution; the mixed solution is then transferred to a 25 mL stainless steel reactor lined with polytetrafluoroethylene, and reacted at 160℃ for 3 days. After cooling, colorless blocky crystals are obtained, which are then filtered, washed, and dried to obtain an isopolymolybdic acid hybrid resistive switching memory material based on tetraphenylethylene molecules; the isopolymolybdic acid is [( n -C4H9)4N]4(Mo8O 26 The tetraphenylethylene molecule is 4-[4-(1,2,2-triphenylvinyl)phenyl]pyridine.

2. The method for preparing a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules as described in claim 1, characterized in that, The cooling process involves reducing the temperature to 30°C over a period of two days.

3. The method for preparing a polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules as described in claim 1, characterized in that: The washing reagent is distilled water; the drying is performed under vacuum at 40°C.

4. A polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules, characterized in that: The polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is prepared using the preparation method of polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules as described in any one of claims 1-3.

5. An application of the isopolymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules as described in claim 4, characterized in that: The polymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules is used as a resistive switching memory layer in multi-level memristors.

6. The application of the isopolymolybdate hybrid resistive switching memory material based on tetraphenylethylene molecules as described in claim 5, characterized in that: The multi-stage memristor has a sandwich structure consisting of a bottom electrode, a resistive switching storage layer, and a top electrode; the bottom electrode is a fluorine-doped indium tin oxide conductive material; and the top electrode is an inert metal material.

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