Monomolecular device based on supramolecular induced electrochemical polymerization and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor devices, in particular to a monomolecular device based on supramolecular induced electrochemical polymerization and a preparation method thereof.The molecular device comprises a graphene point electrode pair and a monomolecular chain, and the monomolecular chain is connected between the graphene point electrode pair; wherein the single molecular chain is formed through supramolecular induced electrochemical polymerization; the host molecule encompasses the guest molecule in the cylindrical cavity of the host molecule to form a supramolecule; the host molecule is selected from cyclodextrin, and the guest molecule is selected from thiophene or thiophene derivatives; the tail ends of the graphene point electrode pairs are modified by amino-containing monomer molecules respectively, the monomer molecules are connected with the graphene point electrode pairs through amido bonds, and the monomer molecules serve as a starting unit and a terminating unit of supramolecular induced electrochemical polymerization, so that assembly of functional cores of a monomolecular device is facilitated; according to the technical scheme provided by the invention, the problem of how to prepare an efficient and reliable monomolecular device by utilizing an electrochemical polymerization method is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a single-molecule device based on supramolecular induced electrochemical polymerization and a preparation method thereof. Background Art

[0002] Single-molecule devices are only a few nanometers in size and have a smaller size and higher integration than traditional transistors. In the semiconductor industry, single-molecule devices provide a new development path for the miniaturization of transistor components. Single-molecule devices use single molecules, a small number of molecules, or conductive polymers to build functional units to achieve functions such as information detection, conversion, transmission, storage, and processing.

[0003] Electrochemical polymerization is a technology that uses electrochemical methods to catalyze the polymerization of organic matter on the electrode surface or in the solution. This method uses electric current to pass through electrolytes or electrolyze polymers, introduces specific monomer units, causes chemical bonds between monomers to form, and finally generates polymers. Electrochemical polymerization has the characteristics of high efficiency, environmental protection, and strong controllability.

[0004] How to use electrochemical polymerization to prepare efficient and reliable single-molecule devices is a technical problem that needs to be solved urgently. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the first object of the present invention is to provide a single-molecule device based on supramolecular induced electrochemical polymerization; the second object of the present invention is to provide a method for preparing a single-molecule device.

[0006] In order to achieve the first purpose, the technical solution adopted by the present invention is: A single-molecule device based on supramolecular induced electrochemical polymerization, comprising a graphene point electrode pair and a single-molecule chain, wherein the single-molecule chain is connected between the graphene point electrode pair; Wherein, the single molecule chain is formed by electrochemical polymerization of supramolecules; The supramolecule includes a host molecule and a guest molecule, and the host molecule encapsulates the guest molecule in its cylindrical cavity to form the supramolecule; The host molecule is selected from cyclodextrin, and the guest molecule is selected from thiophene or thiophene derivatives; Cyclodextrin is a type of cyclic oligosaccharide molecule composed of multiple glucose molecules connected by α-1,4 glycosidic bonds. According to the number of glucose units, there are three common types of cyclodextrin: α-cyclodextrin (6 glucose units), β-cyclodextrin (7 glucose units) and γ-cyclodextrin (8 glucose units). The inner cavity of cyclodextrin is hydrophobic, while the outer cavity is hydrophilic, which enables cyclodextrin to form inclusion complexes, accommodate and stabilize hydrophobic molecules, increase their solubility or improve their stability. Cyclodextrin can interact with thiophene molecules through the hydrophobic effect of its inner cavity to form supramolecular inclusion complexes. During the inclusion process, the guest molecule thiophene or thiophene derivative enters the inner cavity of cyclodextrin, and the hydrophilic part of the outer part interacts with the solvent. Based on this supramolecular structure, the inclusion complex can achieve supramolecular polymerization through electrochemical reactions to form functional core units with supramolecular polymers as single molecular chains. The ends of the graphene point electrode pair are respectively modified by amino-containing monomer molecules, the monomer molecules are connected to the graphene point electrode pair via amide bonds, and the monomer molecules serve as the starting unit and the terminating unit of the supramolecular induced electrochemical polymerization.

[0007] Furthermore, the cyclodextrin is selected from any one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

[0008] Furthermore, the guest molecule is selected from any one of the following structural formulas: , , , , , , , , , , and .

[0009] Furthermore, the structural formula of the monomer molecule is selected from any one of the following structural formulas: , , and .

[0010] Furthermore, the graphene point electrodes are arranged in an array.

[0011] In order to achieve the second purpose, the technical solution adopted by the present invention is: A method for preparing a single-molecule device, for preparing any of the above-mentioned single-molecule devices based on supramolecular induced electrochemical polymerization, comprising the following steps: S100, preparing a single-layer graphene by chemical vapor deposition, and transferring the single-layer graphene to a first substrate to obtain a second substrate covered with the single-layer graphene; S200, preparing a graphene strip with a metal electrode on a second substrate by photolithography and thermal evaporation; S300, preparing a graphene dot electrode pair with carboxyl groups at the ends by using an etching technique and the graphene strip with the metal electrode; S400, using an amide condensation reaction to connect the amino-containing monomer molecules to the graphene point electrode pair through amide bonds, thereby obtaining a graphene point electrode pair modified with a start unit and a stop unit, respectively; S500, preparing an electrolyte for electrochemical polymerization, wherein the electrolyte is a mixed solution including supramolecules and electrolytes; The supramolecule is prepared by using a host molecule compound and a guest molecule compound, and the molar ratio of the host molecule compound to the guest molecule compound is 1:1 to 3:1; S600, making the electrolyte wet the graphene dot electrode pair modified with the starting unit and the terminating unit obtained in step S400, passing an electrical signal to drive the supramolecular polymerization in the electrolyte between the starting unit and the terminating unit of the graphene dot electrode pair, and obtaining a single molecule device based on supramolecular induced electrochemical polymerization.

[0012] Furthermore, in step S500, the electrolyte is selected from at least one of polystyrene sulfonic acid, tetra-n-butylammonium hexafluorophosphonate, morpholineethanesulfonic acid and p-toluenesulfonic acid.

[0013] Furthermore, in step S500, the solvent of the mixed solution is selected from at least one of water, dimethyl sulfoxide, propylene carbonate, acetonitrile and N,N-dimethylformamide.

[0014] Furthermore, step S500 also includes a process of adjusting the pH of the electrolyte using an acid, wherein the acid is selected from at least one of hydrochloric acid and trifluoroacetic acid.

[0015] Furthermore, in step S600, the electrical signal introduced during the electrochemical polymerization process is selected from a constant voltage signal.

[0016] The above one or more technical solutions in the embodiments of the present invention have at least one of the following technical effects: The present invention provides a single-molecule device based on supramolecular induced electrochemical polymerization and a preparation method thereof, wherein a host molecule is used to encapsulate a guest molecule in its cylindrical cavity to form a supramolecular; the host molecule is selected from cyclodextrin, and its inner cavity is hydrophobic and its outer cavity is hydrophilic, which enables it to encapsulate the guest molecule thiophene or thiophene derivative, thereby increasing the solubility of the guest molecule and improving the stability of the guest molecule; the supramolecular is formed into a supramolecular polymer through an electrochemical polymerization reaction, bridged between the graphene point electrode pairs, and the amide condensation reaction is used to covalently graft monomer molecular groups on the edge of the graphene point electrode, providing a starting site and a termination site for the chemical polymerization reaction, thereby realizing the assembly of the functional core of the single-molecule device. The technical solution provided by the present invention solves the problem of how to prepare efficient and reliable single-molecule devices using the electrochemical polymerization method.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of a single-molecule device based on supramolecular induced electrochemical polymerization provided in an embodiment of the present invention.

[0020] Figure 2 It is a schematic diagram of the supramolecular structure provided by an embodiment of the present invention.

[0021] Figure 3 This is a cyclic voltammetry curve of the supramolecule provided in Example 1 of the present invention in an electrolyte.

[0022] Figure 4 This is a curve diagram showing the relationship between current and time during the electrochemical polymerization of the supramolecule in Example 1 of the present invention.

[0023] Figure 5 This is a graph showing the IV characteristics of a single-molecule device based on supramolecular induced electrochemical polymerization provided in Example 1 of the present invention.

[0024] Figure 6 This is a cyclic voltammetry curve of the supramolecule provided by Example 2 of the present invention in an electrolyte.

[0025] Figure 7This is a graph showing the relationship between current and time during the electrochemical polymerization of the supramolecule in Example 2 of the present invention.

[0026] Figure 8 This is a graph of IV characteristic curves of 15 different single-molecule devices based on supramolecular induced electrochemical polymerization provided in Example 2 of the present invention.

[0027] Reference numerals: 100. Graphene dot electrode pair; 200. Single molecule chain; 210. Supramolecular; 211. Host molecule; 212. Guest molecule. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme in the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0029] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and are carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used are all commercially available unless otherwise specified.

[0030] like Figure 1 As shown, a single molecule device based on supramolecular induced electrochemical polymerization includes a graphene point electrode pair 100 and a single molecule chain 200, wherein the single molecule chain 200 is connected between the graphene point electrode pair 100; Wherein, the single molecule chain 200 is formed by electrochemical polymerization induced by the supramolecule 210; like Figure 2 As shown, the supramolecule 210 includes a host molecule 211 and a guest molecule 212. The host molecule 211 includes the guest molecule 212 in its cylindrical cavity to form the supramolecule 210. The host molecule is selected from cyclodextrin, and the guest molecule is selected from thiophene or thiophene derivatives; The ends of the graphene point electrode pair are respectively modified by amino-containing monomer molecules, the monomer molecules are connected to the graphene point electrode pair via amide bonds, and the monomer molecules serve as the starting unit and the terminating unit of the supramolecular induced electrochemical polymerization.

[0031] The cyclodextrin is selected from any one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin. Preferably, the cyclodextrin is selected from β-cyclodextrin, and its structural formula is as follows: .

[0032] Preferably, the guest molecule is selected from any one of the following structural formulas: , , , , , , , , , , and .

[0033] Preferably, the structural formula of the monomer molecule is selected from any one of the following structural formulas: , , and .

[0034] A method for preparing a single-molecule device, for preparing a single-molecule device based on supramolecular induced electrochemical polymerization, comprises the following steps: S100, preparing a single-layer graphene by chemical vapor deposition, and transferring the single-layer graphene to a first substrate to obtain a second substrate covered with the single-layer graphene; S200, preparing a graphene strip with a metal electrode on a second substrate by photolithography and thermal evaporation; S300, preparing a graphene dot electrode pair with carboxyl groups at the ends by using an etching technique and the graphene strip with the metal electrode; S400, using an amide condensation reaction to connect the amino-containing monomer molecules to the graphene point electrode pair through amide bonds, thereby obtaining a graphene point electrode pair modified with a start unit and a stop unit, respectively; S500, preparing an electrolyte for electrochemical polymerization, wherein the electrolyte is a mixed solution including supramolecules and electrolytes; The supramolecule is prepared by using a host molecule compound and a guest molecule compound, and the molar ratio of the host molecule compound to the guest molecule compound is 1:1 to 3:1; S600, making the electrolyte wet the graphene dot electrode pair modified with the starting unit and the terminating unit obtained in step S400, passing an electrical signal to drive the supramolecular polymerization in the electrolyte between the starting unit and the terminating unit of the graphene dot electrode pair, and obtaining a single molecule device based on supramolecular induced electrochemical polymerization.

[0035] Example 1 1. Prepare a single-layer graphene by chemical vapor deposition, transfer the single-layer graphene to a first substrate, and obtain a second substrate covered with a single-layer graphene. The specific process is as follows: A copper sheet with a thickness of 25 µm was immersed in an acetic acid solution for 20 min to remove the oxide on the surface of the copper sheet, and then rinsed and dried and annealed in a tube furnace; then a single layer of graphene was obtained by chemical vapor deposition using methane as a carbon source; polymethyl methacrylate (PMMA) was first spin-coated on the copper sheet with graphene grown on it, and then heated and cured at 180°C for 2 min to form a dense film on the graphene surface; 2 mol / L ferric chloride was used for etching for 30 min to remove the copper substrate, and the ferric chloride on the film was removed after multiple rinses with hydrochloric acid solution and water, and finally transferred to a clean first substrate, which was a silicon wafer covered with 300 nm SiO2, and the moisture was completely removed by natural drying; the graphene / PMMA film transferred to the surface of the first substrate was rinsed with acetone to remove the PMMA, and a second substrate covered with a single layer of graphene was obtained.

[0036] 2. Graphene strips with metal electrodes are prepared on the second substrate by photolithography and thermal evaporation. The specific process is as follows: The second substrate obtained above was placed in the center of the suction cup of the coating machine, and 1 to 2 drops of AR-P 5350 type ultraviolet photoresist were added. The pre-rotation speed of the coating machine was 600 r / min for 6 s, and the rotation speed was 4000 r / min for 45 s. The photoresist was cured by heating on a hot stage at 110 °C for 3 min. The pattern of the mask was exposed on the surface of the second substrate using a 365 nm ultraviolet exposure machine (exposure time 25 s), and the development was about 20 s. It was fixed in deionized water for about 10 s, and then the impurities remaining on the surface were rinsed and dried. 80 Å of Cr and 600 Å of Au were evaporated using a thermal evaporator. After the coating was completed, the second substrate was immersed in acetone for more than 10 h, the photoresist was removed with acetone, and it was blown dry with nitrogen. After evaporation, there were cross and digital marks, and the distance between the marks was 200 μm. A 40-mm-wide strip was obtained by further photolithography. The remaining graphene is removed by oxygen plasma etching. On this basis, a layer of metal electrode is laid on the graphene strip by photolithography and metal deposition to obtain a graphene strip with a metal electrode.

[0037] 3. Using etching technology and the graphene strip with metal electrode to prepare graphene dot electrode pairs with carboxyl groups at the end, the specific process is as follows: A PMMA protective layer is spin-coated on the graphene strip with the metal electrode, and a 5 nm wide dotted line is exposed in the direction perpendicular to the graphene strip by electron beam exposure technology; a series of dotted line windows are obtained on the PMMA protective layer by developing with a developer and fixing with a fixer; the exposed graphene is then etched with oxygen plasma, and the window is further enlarged under the etching action of the oxygen plasma, and the conductivity of the device is monitored during the etching process. When the conductivity gradually decreases to 0, it can be judged that the graphene is just cut off at this time, and a graphene point electrode pair with a carboxyl end is obtained, and the graphene point electrode pair includes a graphene point source terminal electrode and a graphene point drain terminal electrode; Among them, the gap size between the graphene point source terminal electrode and the graphene point drain terminal electrode can be controlled by controlling the etching time.

[0038] Fourth, by utilizing an amide condensation reaction, the amino-containing monomer molecules are connected to the graphene dot electrode pair through an amide bond to obtain a graphene dot electrode pair modified with a start unit and a stop unit, respectively. The specific process is as follows: Place the graphene electrode pair with carboxyl groups at the end in a three-necked flask and add (1 mg) and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (25 mg), sealed, evacuated and vented three times to ensure that there was no water and oxygen in the bottle, replaced the air in the bottle with argon, introduced nitrogen to balance the air pressure, added 10 mL of pyridine into the three-necked flask, and allowed to react in the dark for 48 h. After the reaction, the graphene dot electrode pair was taken out, rinsed with acetone and deionized water three times respectively, and dried with nitrogen to obtain a graphene dot electrode pair modified with the starting unit and the terminating unit, respectively.

[0039] 5. Prepare the electrolyte. The specific process is as follows: Will (0.02 mol), polystyrene sulfonic acid (0.02 mol) and β-cyclodextrin (0.04 mol) were dissolved in water (1 ml), dispersed evenly by ultrasonication and allowed to stand for 24 h to form a mixed solution of supramolecules of thiophene molecules encapsulated by β-cyclodextrin and polystyrene sulfonic acid. Then, an appropriate amount of hydrochloric acid was added to the mixed solution, and the pH of the mixed solution was adjusted to between 2 and 3 to obtain an electrolyte for electrochemical polymerization.

[0040] 6. The electrolyte is made to wet the graphene dot electrode pair modified with the starting unit and the terminating unit, and an electrical signal is introduced to drive the supramolecular polymerization in the electrolyte between the starting unit and the terminating unit of the graphene dot electrode pair. At the same time, under the action of Coulomb traction, a bridged single-molecule chain functional core is constructed between the gaps of the graphene dot electrode pair to obtain a single-molecule device based on supramolecular induced electrochemical polymerization. The specific process is as follows: After amidation, A PMMA micro-liquid tank with a lid on the top is placed on the surface of the graphene point electrode pair of the molecule. The micro-liquid tank is provided with a through slot running through from top to bottom. A small amount of electrolyte is dripped into the micro-liquid tank to soak the graphene point electrode pair. The lid is closed to reduce the volatilization of the solvent. A pair of graphene point electrode pairs is selected and a cyclic voltammetry test is performed on the double electrode system using a semiconductor parameter instrument to obtain a cyclic voltammetry curve, as shown in FIG. Figure 3 As shown in the figure, the results show that the cyclic voltammetry curve has an oxidation peak at about 1 V, which determines that the polymerization voltage is about 1.5 V. Subsequently, a constant voltage of 1.5 V is applied. Under the action of the constant voltage, the guest molecules in the supramolecule rapidly polymerize, and the current suddenly increases from the initial pA level current to about 5 nA at 150 s, as shown in the figure. Figure 4 As shown, the interrupted device is polymerized into a single-molecule chain functional core with β-cyclodextrin on the outside through the guest molecule, thereby achieving bridging between the graphene point electrode pairs.

[0041] 7. The single-molecule device based on supramolecular induced electrochemical polymerization obtained above was tested, and its current at 1 V was tested three times to see whether it was greater than 1 nA. The specific testing process is as follows: Use the probe station and source meter to input a voltage from -1 V to 1 V to the graphene electrode pair. Repeat the cycle three times and read the current of the graphene electrode pair at ±1 V. The three currents are all greater than 1 nA. Figure 5 As shown, the results indicate that the graphene dot electrode pairs are successfully connected through the single molecular chain formed by the supramolecular.

[0042] Example 2 Compared with Example 1, this embodiment has the following differences: 1. Replace the monomer molecules used in the modified starting unit and the ending unit with (1mg); 2. The electrolyte composition and preparation process are different. The preparation process of the electrolyte in this embodiment is as follows: Will (0.02 mol) and β-cyclodextrin (0.02 mol) were dissolved in dimethyl sulfoxide (1 ml), and after ultrasonic dispersion, the mixture was allowed to stand for 24 h to form a β-cyclodextrin inclusion complex. A supramolecular solution is prepared, and then morpholineethanesulfonic acid (0.01 mol) and an appropriate amount of hydrochloric acid are added to the supramolecular solution to adjust the pH of the solution to about 3, thereby obtaining an electrolyte for electrochemical polymerization; The rest of the preparation process is the same as in Example 1.

[0043] The single-molecule device based on supramolecular induced electrochemical polymerization provided in this embodiment can detect whether the single-molecule chain is successful or not. Figure 6 , Figure 7 As shown, the results indicate that the single molecular chain formed by the supramolecule successfully realizes the connection of graphene point electrode pairs.

[0044] The current of 15 single-molecule devices based on supramolecular induced electrochemical polymerization provided in this embodiment was tested in the voltage range of -1 V to 1 V, and the IV curve was obtained by repeating three times to observe whether the current was greater than 1 nA. Figure 8 As shown, Figure A to Figure O are the detection results of the 1st to 15th single-molecule devices based on supramolecular induced electrochemical polymerization, respectively. The results indicate that the functional core single-molecule chain was successfully bridged between the graphene point electrodes by using supramolecular induced electrochemical polymerization.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single-molecule device based on supramolecular induced electrochemical polymerization, characterized in that: It comprises a graphene point electrode pair and a single molecule chain, wherein the single molecule chain is connected between the graphene point electrode pair; Wherein, the single molecule chain is formed by supramolecular induced electrochemical polymerization; The supramolecule includes a host molecule and a guest molecule, and the host molecule encloses the guest molecule in its cylindrical cavity to form the supramolecule; The host molecule is selected from cyclodextrin, and the guest molecule is selected from thiophene or thiophene derivatives; The ends of the graphene point electrode pair are respectively modified by amino-containing monomer molecules, the monomer molecules are connected to the graphene point electrode pair via amide bonds, and the monomer molecules serve as the starting unit and the terminating unit of the supramolecular induced electrochemical polymerization.

2. The single-molecule device based on supramolecular induced electrochemical polymerization according to claim 1, characterized in that: The cyclodextrin is selected from any one of α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin.

3. The single-molecule device based on supramolecular induced electrochemical polymerization according to claim 1, characterized in that: The guest molecule is selected from any one of the following structural formulas: , , , , , , , , , , and .

4. The single-molecule device based on supramolecular induced electrochemical polymerization according to claim 1, characterized in that: The structural formula of the monomer molecule is selected from any one of the following structural formulas: , , and .

5. The single-molecule device based on supramolecular induced electrochemical polymerization according to claim 1, characterized in that: The graphene point electrodes are arranged in an array.

6. A method for preparing a single-molecule device, characterized in that: The method for preparing a single-molecule device based on supramolecular induced electrochemical polymerization as claimed in any one of claims 1 to 5 comprises the following steps: S100, preparing a single-layer graphene by chemical vapor deposition, and transferring the single-layer graphene to a first substrate to obtain a second substrate covered with the single-layer graphene; S200, preparing a graphene strip with a metal electrode on a second substrate by photolithography and thermal evaporation; S300, preparing a graphene dot electrode pair with carboxyl groups at the ends by using an etching technique and the graphene strip with the metal electrode; S400, using an amide condensation reaction to connect the amino-containing monomer molecules to the graphene point electrode pair through amide bonds, thereby obtaining a graphene point electrode pair modified with a start unit and a stop unit, respectively; S500, preparing an electrolyte for electrochemical polymerization, wherein the electrolyte is a mixed solution including supramolecules and electrolytes; The supramolecule is prepared by using a host molecule compound and a guest molecule compound, and the molar ratio of the host molecule compound to the guest molecule compound is 1:1 to 3:1; S600, allowing the electrolyte to wet the graphene dot electrode pair modified with the starting unit and the terminating unit obtained in step S400, and passing an electrical signal to drive the supramolecular polymerization in the electrolyte between the starting unit and the terminating unit of the graphene dot electrode pair to obtain a single molecule device based on supramolecular induced electrochemical polymerization.

7. The method for preparing a single-molecule device according to claim 6, characterized in that: In step S500, the electrolyte is selected from at least one of polystyrene sulfonic acid, tetra-n-butylammonium hexafluorophosphonate, morpholineethanesulfonic acid and p-toluenesulfonic acid.

8. The method for preparing a single-molecule device according to claim 6, characterized in that: In step S500, the solvent of the mixed solution is selected from at least one of water, dimethyl sulfoxide, propylene carbonate, acetonitrile and N,N-dimethylformamide.

9. The method for preparing a single-molecule device according to claim 6, characterized in that: Step S500 also includes a process of adjusting the pH of the electrolyte using an acid, wherein the acid is selected from at least one of hydrochloric acid and trifluoroacetic acid.

10. The method for preparing a single-molecule device according to claim 6, characterized in that: In step S600, the electrical signal introduced during the electrochemical polymerization process is selected from a constant voltage signal.

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