Carbazole derivative monomolecular layer, preparation method therefor, transistor memory and fabrication method therefor

Abstract

Disclosed in the present application are a carbazole derivative monomolecular layer, a preparation method thereof, a transistor memory and a fabrication method therefor, relating to the technical fields of organic storage and information. The transistor memory comprises a source / drain electrode, a semiconductor layer, a carbazole derivative monomolecular layer, a gate insulating layer, a substrate and a gate electrode which are sequentially arranged. The present application prepares a carbazole derivative monomolecular layer and applies same to organic field effect transistor memories to act as a charge trapping layer of devices. The present application involves a simple operation process and low cost, shortens preparation periods while reducing the difficulty in fabrication of transistor memories, and improves the storage performance and stability of transistor memories.

Description

A carbazole derivative monolayer and its preparation method, and a transistor memory and its preparation method. Technical Field

[0001] This application relates to the fields of organic storage and information technology, and in particular to a carbazole derivative monolayer and its preparation method, and a transistor memory and its preparation method. Background Technology

[0002] Human society is rapidly entering the interconnected era, with data exploding and the demand for memory chips surging. As the home of data, memory is an indispensable element of information technology and artificial intelligence. This demands that memory have faster read / write speeds, smaller size, higher storage density, and simpler manufacturing processes. It should also be flexible, lightweight, and portable. Emerging memory technologies mainly include phase-change PCM, ferroelectric RAM, magnetic RAM, memristors, and flash memory. Compared to inorganic memory materials, organic materials have many advantages, such as lower cost, solution processing capability, large-area fabrication, and compatibility with flexible substrates.

[0003] In recent years, numerous theoretical and experimental results have shown that carrier transport in OFETs occurs only within a single layer near the interface between the semiconductor and dielectric layers. Compared to traditional transistors, monolayer thin-film field-effect transistors possess many unique advantages, such as visible transport channels, lower contact resistance, and greater flexibility and transparency. These results indicate that monolayer thin-film transistors are not only beneficial for characterizing the relationship between the structure and properties of organic semiconductor materials, but also provide a feasible research approach for constructing next-generation high-performance organic electronic products.

[0004] However, the fabrication processes for monolayer thin-film devices remain limited, primarily including self-assembly (SAM), Langmuir-Blodgett (LB), physical vapor deposition (PVD), and other coating techniques. These processes inherently possess certain limitations, leading to problems with organic field-effect transistor (OFET) memories such as harsh fabrication environments, long fabrication cycles, poor durability and stability, and low storage density.

[0005] Summary of the Invention

[0006] In view of the shortcomings of the above-mentioned related technologies, this application provides a carbazole derivative monolayer and its preparation method, as well as a transistor memory and its preparation method. This application prepares a carbazole derivative monolayer and applies it in an organic field-effect transistor memory to act as a charge trapping layer. The process is simple and low-cost, reducing the difficulty of transistor memory preparation while shortening the preparation cycle and improving the storage performance and stability of the transistor memory.

[0007] Firstly, the carbazole derivative monolayer provided in this application adopts the following technical solution:

[0008] A carbazole derivative monolayer comprising any one of the following general structural formulas:

[0009] Where n is a natural number from 1 to 100, and m is a natural number from 1 to 100;

[0010] It is a fluorene derivative;

[0011] It is a benzene derivative;

[0012] Selected from Any one of them;

[0013] Selected from Any one of them.

[0014] Preferably, It is a fluorenyl derivative, selected from Any one of the following; where R is an alkyl chain or a halogen atom.

[0015] Preferably, It is a benzene derivative, selected from Any one of them; where R1 is an alkyl chain.

[0016] Preferably, the specific structural formula of the carbazole derivative monolayer is one of the following formulas:

[0017] Secondly, the method for preparing a carbazole derivative monolayer provided in this application adopts the following technical solution:

[0018] A method for preparing a carbazole derivative monolayer includes the following steps: reacting a carbazole derivative with a 3-chloroalkylalkyldialkoxysilane to obtain an intermediate product, and condensing the intermediate product with a hydroxylated modified substrate to obtain the carbazole derivative monolayer.

[0019] Preferably, the molar ratio of the carbazole derivative to the 3-chloroalkylalkyldialkoxysilane is 1:2-10.

[0020] Preferably, the molar ratio of the carbazole derivative to the 3-chloroalkylalkyldialkoxysilane is 1:2.

[0021] Preferably, the molar ratio of the carbazole derivative to the 3-chloroalkylalkyldialkoxysilane is 1:3.

[0022] Preferably, the molar ratio of the carbazole derivative to the 3-chloroalkylalkyldialkoxysilane is 1:10.

[0023] Preferably, the hydroxylated modified substrate is prepared by the following steps: mixing sulfuric acid and hydrogen peroxide to prepare a mixed solution, and immersing the silicon wafer in the mixed solution.

[0024] Preferably, in the mixed solution, the molar ratio of sulfuric acid to hydrogen peroxide is 2.8-3.2:1.

[0025] Preferably, the molar ratio of sulfuric acid to hydrogen peroxide in the mixed solution is 3:1.

[0026] Preferably, the general structural formula of the carbazole derivative includes the following formula:

[0027] One of them.

[0028] Preferably, the specific structural formula of the carbazole derivative monolayer is one of the following formulas:

[0029] Preferably, the intermediate product has a specific structural formula of one of the following:

[0030] Thirdly, the organic field-effect transistor memory provided in this application adopts the following technical solution:

[0031] An organic field-effect transistor memory includes source and drain electrodes, a semiconductor layer, a carbazole derivative monolayer, a gate insulating layer, a substrate, and a gate electrode arranged sequentially.

[0032] Preferably, the source / drain electrodes and the gate electrode are made of metal, organic materials, or inorganic materials.

[0033] Preferably, the source / drain electrodes and the gate electrode are made of one or more of highly doped silicon, gold, silver, copper, and aluminum.

[0034] Preferably, the semiconductor layer is made of one or more of the following: pentacene, tetraacene, copper phthalocyanine, copper phthalocyanine fluoride, red fluorene, triacene, and 3-hexylthiophene.

[0035] Preferably, the gate insulating layer is made of one or more of silicon dioxide, aluminum oxide, zirconium oxide, polystyrene, and polyvinylpyrrolidone.

[0036] Preferably, the thickness of the gate insulating layer is 50-300 nm.

[0037] Preferably, the substrate is one or more of highly doped silicon wafers, glass sheets, and polyethylene terephthalate sheets.

[0038] Preferably, the thickness of the carbazole derivative monolayer is 1-10 nm.

[0039] Fourthly, the method for fabricating an organic field-effect transistor memory provided in this application adopts the following technical solution:

[0040] A method for fabricating an organic field-effect transistor memory includes the following steps: forming a gate electrode and a gate insulating layer on a substrate, and after ultrasonic cleaning and drying, placing the substrate in a mixed solution and heating it at 88-92℃ for 0.8-1.5h, followed by washing and drying to obtain a hydroxylated modified substrate; mixing a carbazole derivative, a catalyst, tetrahydrofuran, and 3-chloroalkylalkyldialkoxysilane and reacting them at 78-82℃ for 60-80h to obtain an intermediate product; placing the hydroxylated modified substrate in a solution of the intermediate product and reacting it at 65-75℃ for 10-14h, followed by washing and drying to obtain a substrate with a carbazole derivative monolayer; fabricating an organic semiconductor layer on the carbazole derivative monolayer, and fabricating source and drain electrodes on the semiconductor layer.

[0041] Preferably, the method includes the following steps: forming a gate electrode and a gate insulating layer on a substrate, and after ultrasonic cleaning and drying, placing the substrate in a mixed solution, heating it at 90°C for 1 hour, washing and drying it to obtain a hydroxylated modified substrate; mixing a carbazole derivative, a catalyst, tetrahydrofuran, and 3-chloroalkylalkyldialkoxysilane and reacting it at 80°C for 72 hours to obtain an intermediate product; placing the hydroxylated modified substrate in a solution of the intermediate product and reacting it at 70°C for 12 hours, washing and drying it to obtain a substrate with a carbazole derivative monolayer; preparing a semiconductor layer on the carbazole derivative monolayer, and preparing source and drain electrodes on the organic semiconductor layer.

[0042] Preferably, the concentration of the intermediate product in the solution is 2-5 mg / mL.

[0043] Preferably, the concentration of the intermediate product in the solution is 3 mg / mL.

[0044] Preferably, the semiconductor layer is a pentacene layer.

[0045] Preferably, the thickness of the pentacene layer is 20-50 nm.

[0046] Preferably, the thickness of the pentacene layer is 30 nm.

[0047] Preferably, the pentacene layer is obtained by vacuum evaporation at a evaporation rate of [missing information]. Vacuum degree controlled at 6×10 -5 -6×10 -4 Pa.

[0048] Preferably, the source and drain electrodes are copper electrodes.

[0049] Preferably, the thickness of the source and drain electrodes is 50-100 nm.

[0050] Preferably, the copper electrode is obtained by vacuum evaporation at a evaporation rate of [missing information]. Vacuum degree controlled at 6×10 -5 -6×10 -4 Pa.

[0051] In summary, this application includes at least one of the following beneficial technical effects:

[0052] 1. The carbazole derivative monolayer of this application serves as a charge trapping layer, which on the one hand achieves electron storage of 16.2-32.49V, thereby increasing the storage density; on the other hand, the water contact angle reaches 77.67-82.4°, which improves the hydrophobicity of the charge trapping layer and thus improves the stability of the organic field-effect crystal memory tube.

[0053] 2. In this application, the organic field-effect crystal memory tube using a carbazole derivative monolayer as the charge trapping layer maintains an on / off ratio of 2.01 × 10⁻⁶ after 3000 s. 3 -7.76×10 3 This improves the tolerance and storage performance of organic field-effect transistors;

[0054] 3. The carbazole derivative monolayer of this application is formed by solution method, which is simple to prepare, low in cost, and has controllable thickness and high substrate recognition.

[0055] 4. The organic field-effect crystal memory device of this application has high tolerance, storage density and stability, while its structure is simple and its cost is low, which is conducive to commercial production. Attached Figure Description

[0056] Figure 1 is a schematic diagram of the organic field-effect transistor memory of this application.

[0057] Figure 2 is a graph showing the change in the water contact angle on the substrate surface during the fabrication process of the field-effect transistor memory in Embodiment 1 of this application.

[0058] Figure 3 is a graph showing the change in the water contact angle on the substrate surface during the fabrication process of an organic field-effect transistor memory in Embodiment 2 of this application.

[0059] Figure 4 is a graph showing the change in the water contact angle on the substrate surface during the fabrication process of the field-effect transistor memory in Embodiment 3 of this application.

[0060] Figure 5 is a graph showing the change in the water contact angle on the substrate surface during the fabrication process of the field-effect transistor memory in Embodiment 4 of this application.

[0061] Figure 6 is an X-ray photoelectron spectrum of the organic field-effect transistor memory of Embodiment 1 of this application.

[0062] Figure 7 is an X-ray photoelectron spectrum of the organic field-effect transistor memory of Embodiment 2 of this application.

[0063] Figure 8 is an X-ray photoelectron spectrum of the organic field-effect transistor memory of Embodiment 3 of this application.

[0064] Figure 9 is an X-ray photoelectron spectrum of the organic field-effect transistor memory of Embodiment 4 of this application.

[0065] Figure 10 is a forward memory window diagram of the organic field-effect transistor memory of Embodiment 1 of this application.

[0066] Figure 11 is a forward memory window diagram of the organic field-effect transistor memory of Embodiment 2 of this application.

[0067] Figure 12 is a forward storage window diagram of the organic field-effect transistor memory of Embodiment 3 of this application.

[0068] Figure 13 is a forward memory window diagram of the organic field-effect transistor memory of Embodiment 4 of this application.

[0069] Figure 14 is a forward sustaining time diagram of the organic field-effect transistor memory of Embodiment 1 of this application.

[0070] Figure 15 is a forward sustaining time diagram of the organic field-effect transistor memory of Embodiment 2 of this application.

[0071] Figure 16 is a forward sustaining time diagram of the organic field-effect transistor memory of Embodiment 3 of this application.

[0072] Figure 17 is a forward sustaining time diagram of the organic field-effect transistor memory of Embodiment 4 of this application. Detailed Implementation

[0073] The present application will be further described in detail below with reference to the embodiments. The following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific conditions in the following embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the methods used are conventional methods known in the art, and the consumables and reagents used are commercially available. Unless otherwise stated, the technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods or materials similar to or equivalent to those described herein may also be applied to the present invention.

[0074] The raw materials used in the examples and comparative examples are all commercially available. A schematic diagram of the organic field-effect transistor memory fabricated in this application is shown in Figure 1, wherein the gate electrode and source / drain electrodes are both copper, the semiconductor layer is a pentacene layer, the monolayer is a carbazole derivative monolayer, the gate insulating layer is silicon dioxide, and the substrate is heavily doped silicon.

[0075] Example 1

[0076] Embodiment 1 of this application provides an organic field-effect transistor memory, the fabrication steps of which are as follows:

[0077] (1) Before the experiment, dry all the glassware used. Add 0.026 mmol of the following formula A1 to a three-necked flask with nitrogen protection and a spherical condenser. A carbazole derivative (dicarbazole-m-benzoyl), 50 mL of ultra-dry tetrahydrofuran (THF), and 0.06 mmol of anhydrous potassium carbonate as a catalyst were added. A magnetic stirrer was started, and the oil bath was heated to 70 °C and stirred for 1 h. 3 mL of 3-chloropropylmethyldimethoxysilane (in excess) was added dropwise at a rate of 5 seconds per drop. After the addition was complete, the oil bath was heated to 80 °C and the reaction was stirred for 72 h. After the reaction was complete, the mixture was cooled and filtered through a G4 sintered glass core to remove the anhydrous potassium carbonate. The filtrate was then evaporated to dryness to remove tetrahydrofuran and 3-chloropropylmethyldimethoxysilane, yielding the product as shown in Formula B1. Intermediate products.

[0078] (2) Take 42 mL of concentrated sulfuric acid and 18 mL of hydrogen peroxide and prepare a mixed solution in a beaker for later use. Form a gate electrode and a gate insulating layer on the substrate. After ultrasonic cleaning treatment with acetone, ethanol and ultrapure water in sequence and drying, place it in the mixed solution in the beaker for immersion. Heat at 90°C for 1 hour. Then perform pure water rinsing, ethanol rinsing and nitrogen blowing operation in sequence to obtain hydroxylated modified substrate.

[0079] (3) The intermediate product of formula B1 is dissolved in toluene as a solvent to prepare an intermediate product solution with a concentration of 3 mg / mL.

[0080] (4) The hydroxylated modified substrate was immersed in the intermediate product solution and heated at 70°C for 12 hours. After the reaction was completed, it was removed and ultrasonically cleaned with chloroform, acetone, and ethanol for 10 minutes each, and then dried with nitrogen to obtain the substrate with the following structure: C1 A substrate of carbazole derivative monolayer.

[0081] (5) The carbazole derivative monolayer was deposited on the surface of the carbazole derivative using a vacuum evaporation equipment at a evaporation rate of [missing information]. Vacuum degree controlled at 6×10 -5 -6×10 -4 Under conditions of Pa, a 30 nm thick pentamene layer was deposited as the semiconductor layer; then, the substrate with the deposited pentamene layer was removed, a mask was added, and multiple batches of the same process were performed at a deposition rate of Pa. Vacuum degree controlled at 6×10 -5 -6×10 -4 Under the condition of Pa, a copper electrode with a thickness of 60 nm was deposited as the source and drain electrode. The mask was used to control the channel width and length of a single group to be 1000 μm and 100 μm, respectively, to obtain an organic field-effect transistor memory.

[0082] Example 2

[0083] Embodiment 2 of this application provides an organic field-effect transistor memory. The difference between Embodiment 2 and Embodiment 1 is that 0.025 mmol of 0.025 mmol of A2 is used. The carbazole derivative (dicarbazole-m-benzoyl) of formula A1 was replaced with 0.026 mmol of a carbazole derivative (ternary carbazole-m-benzoyl) and 0.08 mmol of anhydrous potassium carbonate was added as a catalyst to prepare formula B2. The intermediate product, by replacing the intermediate product of formula B1 with the intermediate product of formula B2, yields the product of formula C2. A substrate of carbazole derivative monolayer.

[0084] Example 3

[0085] Embodiment 3 of this application provides an organic field-effect transistor memory. The difference between Embodiment 3 and Embodiment 1 is that 0.05 mmol of A3 as shown in the formula is used. The carbazole derivative was used to replace 0.026 mmol of the carbazole derivative (dicarbazole-m-benzoyl) of formula A1 to prepare formula B3. The intermediate product, by replacing the intermediate product of formula B1 with the intermediate product of formula B3, yields a product shaped as shown in formula C3. A substrate of carbazole derivative monolayer.

[0086] Example 4

[0087] Embodiment 4 of this application provides an organic field-effect transistor memory. The difference between Embodiment 4 and Embodiment 1 is that 0.05 mmol of A4 as shown in the formula is used. The carbazole derivative was used to replace 0.026 mmol of the carbazole derivative (dicarbazole-m-benzoyl) of formula A1 to prepare formula B4. The intermediate product, by replacing the intermediate product of formula B1 with the intermediate product of formula B4, yields a product shaped as shown in formula C4. A substrate of carbazole derivative monolayer.

[0088] Testing and Inspection

[0089] (1) During the fabrication process of the organic field-effect transistor memory in Examples 1-4, the water contact angle of the substrates that underwent three-step ultrasonic cleaning treatment with acetone, ethanol, and ultrapure water was measured; the water contact angle of the hydroxylated modified substrates was measured; and the water contact angle of the substrates with a carbazole derivative monolayer was measured. The above results are arranged from left to right to obtain the variation diagram of the water contact angle on the substrate surface, as shown in Figures 2-5.

[0090] (2) The X-ray photoelectron spectra of organic field-effect transistor memories in Examples 1-4 were measured, as shown in Figures 6-9.

[0091] (3) The forward memory window diagrams of organic field-effect transistor memories in Examples 1-4 were measured, as shown in Figures 10-13.

[0092] (4) The forward sustaining time of organic field-effect transistor memories in Examples 1-4 was measured, as shown in Figures 14-17.

[0093] Results Analysis

[0094] The following detailed description of this application is based on the experimental results provided in Figure 1-17.

[0095] Referring to Figures 2-5, it can be seen that the hydrophobicity of the substrate surface in the organic field-effect transistor memory of Examples 1-4 first decreases and then diminishes during the fabrication process. After a carbazole derivative monolayer is formed on the substrate surface, the hydrophobicity reaches its maximum. In the order of Examples 1-4, the water contact angles after forming the carbazole derivative monolayer on the substrate surface are increased to 82.4°, 79.82°, 77.67° and 79.69°, respectively, which improves the hydrophobicity of the charge trapping layer in the organic field-effect transistor memory, thereby improving the stability of the fabricated organic field-effect transistor memory.

[0096] Referring to Figures 6-9, it can be seen that N elements appeared on the substrate surface of the organic field-effect transistor memory in Examples 1-4, where there were originally no N elements, indicating that a carbazole derivative monolayer film was successfully grafted onto the substrate surface.

[0097] Referring to Figures 10-13, the organic field-effect transistor memories of Examples 1-4, under photoelectric control, successively achieved electronic storage of 32.49V, 28.06V, 26.18V, and 16.2V, improving the storage density of the organic field-effect transistor memories. Combined with Figures 2-5, it can be seen that the organic field-effect transistor memory of Example 1 has the largest water contact angle and the largest storage density, indicating that using a binary carbazole-m-benzoyl carbazole derivative to fabricate an organic field-effect transistor memory is beneficial for simultaneously improving the stability and storage performance of the organic field-effect transistor memory.

[0098] Referring to Figures 14-17, the organic field-effect transistor memory of Examples 1-4 maintains an on / off ratio of 5.75 × 10⁻⁶ after 3000 seconds. 3 7.76×10 3 2.88×10 3 With a strength of 2.01 × 10³, it exhibits good tolerance and storage performance, especially the organic field-effect transistor memories of Examples 1 and 2, where the on / off ratio is maintained at 5 × 10³. 3 The above demonstrates that using binary or ternary carbazole-m-benzoyl carbazole as a carbazole derivative to fabricate organic field-effect transistor (OFET) memories is beneficial for improving the robustness and storage performance of OFET memories.

[0099] In summary, the carbazole derivative monolayer and its preparation method provided in this application offer controllable thickness, high substrate recognition, and use of inexpensive toluene solvent. The solution-based film formation method is simple and cost-effective. By using the carbazole derivative monolayer as the organic charge storage layer of an organic field-effect transistor memory, the memory's tolerance, storage density, and stability are improved. The preparation method of the organic field-effect transistor memory in this application is simple, reduces device fabrication costs, and is beneficial for the further development, promotion, and production of future memory devices.

[0100] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A carbazole derivative monolayer, characterized in that: Includes any of the following general structural formulas: Any one of them; Where n is a natural number from 1 to 100, and m is a natural number from 1 to 100; It is a fluorene derivative; It is a benzene derivative; Selected from Any one of them; Selected from Any one of them.

2. A method for preparing a carbazole derivative monolayer as described in claim 1, characterized in that: The process includes the following steps: reacting a carbazole derivative with a 3-chloroalkylalkyldialkoxysilane to obtain an intermediate product, condensing the intermediate product with a hydroxylated modified substrate to obtain a monolayer of the carbazole derivative.

3. The method for preparing a carbazole derivative monolayer according to claim 2, characterized in that: The molar ratio of the carbazole derivative to the 3-chloroalkylalkyldialkoxysilane is 1:2-10.

4. The method for preparing a carbazole derivative monolayer according to claim 2, characterized in that: The hydroxylated modified substrate is prepared by the following steps: mixing sulfuric acid and hydrogen peroxide to prepare a mixed solution, and immersing the substrate in the mixed solution.

5. The method for preparing a carbazole derivative monolayer according to claim 4, characterized in that: In the mixed solution, the molar ratio of sulfuric acid to hydrogen peroxide is 2.8-3.2:

1.

6. The method for preparing a carbazole derivative monolayer according to claim 2, characterized in that: The general structural formula of the carbazole derivative includes the following formula: One of them.

7. An organic field-effect transistor memory, characterized in that: It includes source / drain electrodes, a semiconductor layer, a carbazole derivative monolayer as described in claim 1, a gate insulating layer, a substrate, and a gate electrode arranged sequentially.

8. The organic field-effect transistor memory according to claim 7, characterized in that: The thickness of the carbazole derivative monolayer is 1-10 nm.

9. A method for fabricating an organic field-effect transistor memory as described in claim 7, characterized in that: The process includes the following steps: forming a gate electrode and a gate insulating layer on a substrate, which are then ultrasonically cleaned and dried. The substrate is then placed in a mixed solution and heated at 88-92°C for 0.8-1.5 hours, followed by washing and drying to obtain a hydroxylated modified substrate. A carbazole derivative, a catalyst, tetrahydrofuran, and 3-chloroalkylalkyldialkoxysilane are mixed and reacted at 78-82°C for 60-80 hours to obtain an intermediate product. The hydroxylated modified substrate is placed in a solution of the intermediate product and reacted at 65-75°C for 10-14 hours, followed by washing and drying to obtain a substrate with a carbazole derivative monolayer. An organic semiconductor layer is prepared on the carbazole derivative monolayer, and source / drain electrodes are prepared on the organic semiconductor layer.

10. The method for fabricating an organic field-effect transistor memory according to claim 9, characterized in that: In the solution of the intermediate product, the concentration of the intermediate product is 2-5 mg / mL.

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