High temperature resistant multilevel resistive random access memory based on covalent organic polymer thin films consisting of imine bond connections with different number of beta-ketoenamines

Abstract

The application discloses a kind of based on different β High-temperature-resistant multilevel resistive random access memory composed of ketone enamine number of imine bond connected covalent organic polymer film. The high-temperature-resistant multilevel resistive random access memory material is a kind of based on different β Ketone enamine number of imine bond connected covalent organic polymer film, with different number of hydroxyl side groups aldehyde monomer and 1,3,6,8-tetra(4-aminophenyl)pyrene as reaction monomer, prepared by simple Schiff base condensation reaction. And prepared ITO / Py-COP-n / Ag (n=0, 1 or 2) sandwich structure memory device. In the reaction process, by changing the number of aldehyde monomer containing hydroxyl side groups, it shows ternary yield enhanced high-temperature-resistant multilevel storage performance. In device preparation and performance, it shows flexibility, low cost, high on-off current ratio, low turn-on voltage, high-temperature-resistant and other characteristics, suitable for high-temperature and other harsh environmental conditions of memory device.

Description

Technical Field

[0001] The present invention belongs to the field of memory technology and specifically relates to a memory based on different β A high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds with a number of -keto-enamine groups and a preparation method thereof. Background Art

[0002] Since the pioneering work of Williams and Strukov in 2008, resistive random access memory (RRAM) has experienced rapid development due to its low power consumption, fast switching speed, and good stability. The upcoming era of big data urgently requires the emergence of resistive memory with higher storage density. Multi-level memory can revolutionize data storage density because its three or more conductive states (i.e., 0, 1, 2, and 3) correspond to a storage efficiency of 2. n to 3 / 4 n . Therefore, people are working hard to find new active materials with multi-level resistive memory properties. So far, the following types of materials have been manufactured to realize multi-level memory, namely organic small molecules, polymers and their composites, inorganic compounds (including oxides, perovskites and WSe2 / BN) and inorganic / organic hybrids. In addition, since key technical parameters such as batch uniformity, ON / OFF ratio, set / reset voltage, etc. are still not met, there is still a lot of room for improvement in the performance of its multi-level resistive memory. Among these types, organic devices have attracted much attention due to their chemically tunable functions and solution processability, but some problems including insufficient reproducibility, durability and low switching speed still hinder their practical application. Especially in some special occasions such as geothermal, petroleum, aerospace, etc., memory devices must work in harsh environments such as high temperature, which has promoted the research on intrinsically stable storage materials.

[0003] The present invention is based on different β During the polymerization reaction of the covalent organic polymer material connected by the imine bond of the ketone enamine in a mixed solvent, a film is formed in situ on the substrate (ITO conductive glass), and a device is prepared to obtain a high-temperature resistant multi-level resistive memory. The film material is synthesized using simple and controllable solvent heat. The film surface is smooth and has low roughness. By changing the number of hydroxyl groups of the reactive aldehyde monomer, different β The amount of ketoenamine in the material is then controlled, ultimately regulating the switching behavior of the high-temperature resistant multi-level resistive memory. This invention produces a low-cost, high-on / off current ratio, low turn-on voltage, and high-temperature resistant multi-level resistive memory material suitable for harsh environments (such as high temperatures), demonstrating promising application prospects. Summary of the Invention

[0004] Based on the above analysis, the present invention is further described in detail in conjunction with the accompanying drawings.

[0005] The purpose of the present invention is to provide a β A high-temperature resistant multi-level resistive switching memory (Py-COP-n) (n = 0, 1, or 2) is prepared by a simple Schiff base condensation reaction of aldehyde monomers (trisaldehyde (TFB), 4-hydroxyisophthalaldehyde (HTA), 2,4-dihydroxy-1,3,5-trisaldehyde (DHTA), and 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTTA)) with varying numbers of hydroxyl side groups. The resulting material, Py-COP-n (n = 0, 1, or 2), is a high-temperature resistant multi-level resistive switching memory. The preparation method is simple, with readily available raw materials and easy implementation. Furthermore, the preparation process is free of harmful products, making it an environmentally friendly, green synthesis.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A different β -ketoenamine number of imine bond connected by covalent organic polymer film composed of high temperature resistant multi-level resistive memory, the device structure is as follows Figure 5 The device has a sandwich structure. The bottom electrode can be, but is not limited to, ITO conductive glass. The middle memristor material is a covalent organic polymer film Py-COP-n (n = 0, 1, or 2). The top electrode can be, but is not limited to, Ag.

[0008] The preparation method of the covalent organic polymer thin film material comprises the following steps: first, under a nitrogen atmosphere, dissolving aldehyde monomers (trimethylene oxide (TFB), 4-hydroxyisophthalic acid (HTA), 2,4-dihydroxy-1,3,5-trimethylene oxide (DHTA), and 1,3,6,8-tetrakis(4-aminophenyl)pyrene (PyTTA)) with different numbers of hydroxyl side groups in a mixed solvent and performing ultrasonic treatment; then, adding a substrate (ITO conductive glass) and a catalyst (HOAc) to the mixed solution and performing ultrasonic treatment; degassing cycles under liquid nitrogen three times, placing the reactor in an oven at 90-120°C, and reacting for 6-72 hours; after the reaction, transferring the substrate to dimethylacetamide or o-dichlorobenzene and soaking it for 1 day, and finally drying it in a vacuum oven at 90-120°C.

[0009] Furthermore, the above-mentioned βA method for preparing a high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds with a certain number of ketone enamines, comprising the following steps: adding aldehyde monomers containing different numbers of hydroxyl side groups and 1,3,6,8-tetrakis(4-aminophenyl)pyrene to a mixed solvent, placing ITO conductive glass in a reaction container, adding a catalyst, and performing a solvent thermal polymerization reaction under a nitrogen atmosphere to obtain a covalent organic polymer film material with the ITO conductive glass as a substrate; then preparing a silver electrode on the covalent organic polymer film material to obtain the high-temperature resistant multi-level resistive random access memory.

[0010] Furthermore, the aldehyde monomer containing different numbers of hydroxyl side groups includes one of trimesic acid (TFB), 4-hydroxyphthalic acid (HTA) (CAS: 81502-74-1), and 2,4-dihydroxy-1,3,5-trimethylbenzaldehyde (DHTA).

[0011] Furthermore, the covalent organic polymer film is synthesized by Schiff base condensation reaction using aldehyde monomers containing different numbers of hydroxyl side groups, including one of trimesic acid, 4-hydroxyisophthalic acid, 2,4-dihydroxy-1,3,5-trimesic acid and 1,3,6,8-tetrakis(4-aminophenyl)pyrene, to obtain a series of covalent organic polymer film materials, including Py-COP-0, Py-COP-1, and Py-COP-2.

[0012] Furthermore, the mixed solvent is a mixed solvent of o-dichlorobenzene and dimethylacetamide, with a volume ratio of o-dichlorobenzene:dimethylacetamide = 1:1~1:9.

[0013] Furthermore, the catalyst is acetic acid with a concentration of 3 to 12M.

[0014] Furthermore, the reaction temperature of the solvent thermal polymerization reaction is 90-120 °C, and the reaction time is 6-72 h.

[0015] The significant advantages of the present invention are:

[0016] (1) The covalent organic polymer material obtained in the present invention can form a uniform and dense thin film on a substrate.

[0017] (2) The difference between the present invention and β -keto-enamine covalent organic polymer materials with imine bonds show high-temperature resistant multi-stage storage behavior, especially when 2,4-dihydroxy-1,3,5-benzenetricarboxaldehyde (DHTA) is used as the aldehyde monomer, it shows the highest temperature resistance (450 ℃).

[0018] (3) The raw materials used in the present invention are readily available; the synthesis method is simple to operate; and the device has excellent performance and strong cycle stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 For different income β Schematic diagram of the chemical synthesis of imine-linked covalent organic polymer materials Py-COP-n (n = 0, 1, or 2).

[0020] Figure 2 For different income β -Infrared spectra of the imine-linked covalent organic polymer material Py-COP-n (n = 0, 1, or 2) with the number of ketoenamines.

[0021] Figure 3 For different income β -Thermogravimetric analysis of the imine-linked covalent organic polymer material Py-COP-n (n = 0, 1, or 2) with the number of ketoenamines.

[0022] Figure 4 For different income β -Scanning electron micrographs of the imine-linked covalent organic polymer material Py-COP-n (n = 0, 1, or 2) with different numbers of ketoenamines.

[0023] Figure 5 For different income β -Device structure of the imine-linked covalent organic polymer material Py-COP-n (n = 0, 1, or 2) with the number of ketoenamines.

[0024] Figure 6 The obtained covalent organic polymer material Py-COP-n (n = 0, 1 or 2) device connected by imine bonds was tested at 25 °C. IV Characteristic curve test diagram and ternary yield statistical diagram.

[0025] Figure 7 For different income β - Ketoenamine number of imine bond-connected covalent organic polymer material Py-COP-n (n = 0, 1 or 2) devices at different temperature conditions of 25-450℃, showing the number of cycles of maintaining high and low resistance states. DETAILED DESCRIPTION

[0026] In order to make the contents of the present invention easier to understand, the technical solutions of the present invention are further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0027] Example 1 Preparation of Py-COP-0 polymer film:

[0028] 1) Under inert atmosphere, PyTTA (22.6 mg) and TFB (8.4 mg) were dissolved in o-dichlorobenzene ( o-DCB) and dimethylacetamide (DMAc) in a mixed solvent (2 mL, V DMAc :V o-DCB =7:3), low-temperature ultrasonic treatment for 10 min;

[0029] 2) Add ITO conductive glass (10 mm x 25 mm x 1.1 mm, <10 ohm / sq) and catalyst acetic acid (6 M, 200 μL) to the above mixture and sonicate for 5 min.

[0030] 3) After three vacuum degassing-refilling cycles, the reactor was placed in an oven at 120 °C for 3 days;

[0031] 4) After the reaction is completed, transfer the substrate to dimethylacetamide and soak overnight to remove unreacted raw materials and other impurities;

[0032] 5) Drying the film in a vacuum oven at 60° C. to obtain a Py-COP-0 polymer film material grown on the ITO conductive glass.

[0033] Example 2 Preparation of Py-COP-1 polymer film:

[0034] 1) Under inert atmosphere, PyTTA (22.6 mg) and HTA (9.2 mg) were dissolved in o-dichlorobenzene ( o -DCB) and dimethylacetamide (DMAc) in a mixed solvent (2 mL, V DMAc :V o-DCB =7:3), low-temperature ultrasonic treatment for 10 min;

[0035] 2) Add ITO conductive glass (10 mm x 25 mm x 1.1 mm, <10 ohm / sq) and catalyst acetic acid (6 M, 200 μL) to the above mixture and sonicate for 5 min.

[0036] 3) After three vacuum degassing-refilling cycles, the reactor was placed in an oven at 120 °C for 3 days;

[0037] 4) After the reaction is completed, transfer the substrate to dimethylacetamide and soak overnight to remove unreacted raw materials and other impurities;

[0038] 5) Drying the film in a vacuum oven at 60°C to obtain a Py-COP-1 polymer film material grown on the ITO conductive glass.

[0039] Example 3 Preparation of Py-COP-2 polymer film:

[0040] 1) Under inert atmosphere, PyTTA (22.6 mg) and DHTA (10.09 mg) were dissolved in o-dichlorobenzene ( o -DCB) and dimethylacetamide (DMAc) in a mixed solvent (2 mL, V DMAc :V o-DCB =7:3), low-temperature ultrasonic treatment for 10 min;

[0041] 2) Add ITO conductive glass (10 mm x 25 mm x 1.1 mm, <10 ohm / sq) and catalyst acetic acid (6 M, 200 μL) to the above mixture and sonicate for 5 min.

[0042] 3) After three vacuum degassing-refilling cycles, the reactor was placed in an oven at 120 °C for 3 days;

[0043] 4) After the reaction is completed, transfer the substrate to dimethylacetamide and soak overnight to remove unreacted raw materials and other impurities;

[0044] 5) Drying the film in a vacuum oven at 60°C to obtain a Py-COP-2 polymer film material grown on the ITO conductive glass.

[0045] Figure 2 The Fourier transform infrared spectra of the prepared Py-COP-n (n=0, 1 or 2) are shown in Figure 2. Figure 2 The analysis shows that, taking Py-COP-2 as an example, at 1617 cm -1 The absorption peaks around 1574 cm are attributed to C=O stretching vibration. -1 The absorption peaks around 1277 cm are attributed to C=C stretching vibration. -1 The absorption peaks on the left and right are attributed to the -C=NC stretching vibration.

[0046] Figure 3 Thermogravimetric analysis of the prepared Py-COP-n (n = 0, 1 or 2). Figure 3 Analysis showed that the observed 5% weight loss was probably due to adsorbates and residual unreacted monomers. Even at 800 °C, Py-COP-n (n = 0, 1, or 2) still retained more than 50% of its mass and was thermally stable.

[0047] Figure 4 The SEM images of the prepared Py-COP-n (n=0, 1 or 2) are shown. Figure 4 Analysis shows that the surface of the film is relatively flat and smooth, which is conducive to electron transfer.

[0048] Example 4 Preparation and Evaluation of Py-COP-n (n=0, 1, or 2) Polymer Film-Based High-Temperature Resistant Multi-Level Resistive Memory Devices

[0049] 1) Device Preparation: The Py-COP-n (n = 0, 1, or 2) polymer film was used as a resistive switching active layer to construct a high-temperature resistant multi-level resistive memory device. The device structure, as shown in Figure 5, includes a bottom electrode, an intermediate resistive switching active layer, and a top electrode, namely, ITO / Py-COP-n (n = 0, 1, or 2) / Ag.

[0050] Specifically, the material of the bottom electrode may be, but is not limited to, ITO conductive glass (10 mm*25 mm*1.1 mm, <10 ohm / sq).

[0051] Specifically, the Py-COP-n (n=0, 1, or 2) is a covalent organic polymer thin film material based on PyTTA and aldehyde monomers containing different numbers of hydroxyl groups connected by a solvothermal reaction.

[0052] Specifically, the top electrode material may be, but is not limited to, Ag, wherein the Ag electrode is deposited on a Py-COP-n (n=0, 1, or 2) polymer film by evaporation.

[0053] 2) Device evaluation: ITO / Py-COP-n (n = 0, 1 or 2) / Ag device IV The characteristic curve was measured using a KEYSIGHT-B2901A single-channel semiconductor parameter tester. Specifically, a certain bias voltage range (-5 V to 5 V) was applied and scanned. When the voltage reached the threshold voltage, the current suddenly increased, and the resistance changed from a high resistance state (HRS) to a low resistance state (LRS). This process is called "writing." The voltage at this time is the turn-on voltage (V set ); As the voltage is reversed, the current will suddenly decrease, and the resistance value will change from low resistance state (LRS) to high resistance state (HRS). This process is called "reading". The voltage at this time is the reset voltage (V reset ).

[0054] Table 1 shows the specific performance parameters of the ITO / Py-COP-n (n=0, 1, or 2) / Ag high-temperature multi-level resistive random access memory (RRAM). The ITO / Py-COP-2 / Ag device exhibits excellent memory performance, including the lowest turn-on voltage, the highest on / off current ratio and temperature tolerance, as well as a high ternary storage yield. The introduction of hydroxyl groups enhances intermolecular forces within the molecule, thereby improving molecular stacking and crystal structure, increasing hole transport efficiency, and ultimately enhancing the polymer's optoelectronic properties.

[0055] Table 1 Summary of performance of multi-level resistive memory based on Py-COP-n (n=0, 1 or 2)

[0056]

[0057] like Figure 6 As shown in Figure 2, with the introduction of different amounts of hydroxyl monomers, the turn-on voltage of the ITO / Py-COP-n (n=0, 1, or 2) / Ag device decreased from +2.64 V to +1.29 V, and the on-off current ratio increased from 10 3.3 :1 increased to 10 4.7 :1 1.0 :1, the tolerance temperature and ternary yield can reach 450℃ and 55% respectively.

[0058] like Figure 7 As shown in the figure, the ITO / Py-Tp-COP-n (n=0, 1 or 2) / Ag devices exhibited good stability under different temperature conditions of 25-450 ℃.

[0059] The present invention discloses a high-temperature resistant multi-level resistive random access memory based on Py-COP-n (n=0, 1, or 2), which has the advantages of low turn-on voltage, high current switching ratio, multi-level storage, and high-temperature resistance. It can be widely used in fields such as economic, social development, and national security.

[0060] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A different β A high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds of a number of -keto-enamines, characterized in that: The high temperature resistant multi-level resistive memory is a sandwich structure of bottom electrode / resistive memory layer / top electrode; the bottom electrode is indium tin oxide conductive glass; the top electrode is silver inert metal material; the resistive memory layer is based on different β -Ketoenamine number of imine bonded covalent organic polymer thin film materials; Based on different β A method for preparing a high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds with a certain number of ketoenamines, comprising the following steps: adding aldehyde monomers containing different numbers of hydroxyl side groups and 1,3,6,8-tetrakis(4-aminophenyl)pyrene to a mixed solvent, placing indium tin oxide conductive glass in a reaction container, adding a catalyst, and conducting a solvent thermal polymerization reaction under a nitrogen atmosphere to obtain a covalent organic polymer film material with the indium tin oxide conductive glass as a substrate, and then preparing a silver electrode on the covalent organic polymer film material to obtain the high-temperature resistant multi-level resistive random access memory; The aldehyde monomers containing different numbers of hydroxyl side groups include one of trimesaldehyde, 4-hydroxym-m-benzene trimesaldehyde, and 2,4-dihydroxy-1,3,5-pyromellitic trimesaldehyde; The covalent organic polymer film is a series of covalent organic polymer film materials synthesized by Schiff base condensation reaction using aldehyde monomers containing different numbers of hydroxyl side groups and 1,3,6,8-tetrakis(4-aminophenyl)pyrene as monomers.

2. The method according to claim 1 β A high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds of a number of -keto-enamines, characterized in that: The mixed solvent is a mixed solvent of o-dichlorobenzene and dimethylacetamide, and the volume ratio of o-dichlorobenzene to dimethylacetamide is 1:(1-9).

3. The method according to claim 1 β A high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds of a number of -keto-enamines, characterized in that: The catalyst is acetic acid with a concentration of 3~12M.

4. The method according to claim 1 β A high-temperature resistant multi-level resistive random access memory composed of a covalent organic polymer film connected by imine bonds of a number of -keto-enamines, characterized in that: The reaction temperature of the solvent thermal polymerization reaction is 90-120°C, and the reaction time is 6-72h.

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