STM-BJ polyethylene wax encapsulated probe, and preparation method and application thereof

Abstract

The application provides an STM-BJ polyethylene wax encapsulated probe and a preparation method and application thereof, through preheating to make the polyethylene wax reach a low-viscosity fluid state, controlling a gold wire to vertically pass through a molten polyethylene layer, forming a uniform-thickness insulating sheath layer, and making a needle tip surface of a front end of the gold wire uniformly coated with a polyethylene wax layer. The application adopts polyethylene wax as an encapsulating material, the chemical structure of which is incompatible with common polar solvents and has strong chemical inertness; stable work in various polar solvents is realized, so that it is possible to study molecules that can only be dissolved or function in polar solvents, and the research boundary of single-molecule electrical measurement is greatly expanded. In addition, the polyethylene wax has a lower dielectric constant and a more compact crystal structure, can effectively inhibit ion migration and charge injection, thereby reducing the background leakage current to a very low level, and the extremely low background noise enables the system to detect a molecular signal with a lower conductance value.

Description

Technical Field

[0001] This application belongs to the field of single-molecule detection technology, and in particular relates to an STM-BJ polyethylene wax-encapsulated probe, its preparation method and application. Background Technology

[0002] STM-BJ (Scanning Tunneling Microscopy-Break Junction Technique) is an important tool for studying the conductivity and interface properties of molecular junctions. In this technique, tip encapsulation is crucial for reducing background leakage current, especially in test systems containing electrolytes or polar solvents. Sufficient encapsulation of the tip with insulating materials significantly reduces the impact of solution ions on leakage current. While traditional encapsulation materials such as black wax can reduce leakage current to some extent, their easy dissolution in benzene-based solvents or acid / alkali solvents leads to encapsulation failure, limiting the application of STM-BJ in complex chemical environments.

[0003] In existing technologies, atomic layer deposition (ALD) is also used to deposit inorganic high-dielectric materials such as hafnium dioxide for encapsulation. Although this improves solvent resistance, it also has problems such as complex processes, high equipment requirements, and high costs. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues, and its purpose is to provide a novel probe encapsulation material and preparation method that is simple to operate and can be stably adapted to a variety of solution systems, which can preferentially solve the problem of excessive leakage current in STM-BJ testing.

[0005] To achieve the above objectives, this application provides a novel probe encapsulation material and preparation method that is simple to operate and applicable to benzene-based solvent systems, solving the problem of excessive leakage current in experiments. This set of operating procedures is mainly used in the preparation of low leakage current probes in the single-molecule field to facilitate the detection of weak signals. The probe encapsulation material and method have good insulation, chemical stability and simple preparation, so as to expand the applicable system of STM-BJ technology.

[0006] The first aspect of this application provides an STM-BJ polyethylene wax-encapsulated probe, comprising a gold wire, wherein the gold wire has a needle tip at its front end, and the surface of the needle tip is uniformly coated with a polyethylene wax layer.

[0007] The gold wire has a diameter of 0.25 mm, the needle tip length is 5 mm to 15 mm, and the polyethylene wax layer encapsulation height generally accounts for 50-70% of the needle tip length. Preferably, it is 55-65%, and more preferably, the polyethylene wax layer encapsulation height generally accounts for 58-62% of the needle tip length.

[0008] The polyethylene wax layer has a thickness of 5-50 μm.

[0009] A second aspect of this application also provides a method for preparing an STM-BJ polyethylene wax-encapsulated probe, comprising the following steps: 1) Preparation of gold needle tips: Clean the unencapsulated gold needle tips to remove residual byproducts and avoid contamination; 2) Prepare polyethylene wax: Heat the polyethylene wax powder to above 200℃ to melt it. If the temperature is too low, the polyethylene wax will not dissolve easily. Cool and solidify it into a block at room temperature for later use. 3) Insulation encapsulation of gold needle tip: Take the polyethylene wax block from step 2) and preheat it with a temperature-controlled soldering iron until the polyethylene wax reaches a low viscosity fluid state. Generally, the temperature can be controlled at 220℃~240℃. Control the speed of the gold wire and slowly and vertically pass it through the molten polyethylene layer to form an insulating sheath layer of uniform thickness.

[0010] In any embodiment, the preparation of the unencapsulated gold needle tip is as follows: The gold wire is immersed in anhydrous ethanol and ultrasonically cleaned for 5 minutes to remove surface organic contaminants; a stainless steel needle tube with a gold wire nested inside is used as the working electrode carrier, and a gold ring is used as the reference electrode and counter electrode; an electrolyte is prepared by mixing 37% HCl and ethanol in a 1:1 volume ratio; then a constant potential of 2.2-2.8 V is applied through an electrochemical workstation, and directional dissolution is achieved through an anodic oxidation reaction. The current drops sharply to 0, indicating that the needle tip has broken, thus obtaining the unencapsulated gold needle tip.

[0011] Under the combined effect of surface tension and electric field gradient, the neck of the gold wire preferentially dissolves, forming a conical tip. Subsequently, it is rinsed with isopropanol to remove residual byproducts and avoid contamination.

[0012] The electrolyte is prepared and used immediately. The gold wire, gold needle tip, and gold ring are gold wire, needle tip, and ring.

[0013] In any embodiment, the preheating temperature is 215-225°C, which causes the polyethylene wax to completely melt into a low-viscosity liquid.

[0014] At this temperature, polyethylene wax has suitable fluidity and spreadability, effectively coating the needle tip surface without decomposing or excessively volatilizing due to excessive temperature.

[0015] In any embodiment, during encapsulation in step 3), the temperature is maintained on a constant temperature heating table, and the area to be encapsulated of the fixed gold needle tip is slowly and vertically immersed into the molten polyethylene wax liquid for 3-5 seconds. Too short or too long a time will result in uneven thickness of the encapsulated needle tip; then, the needle tip is vertically pulled out of the liquid surface at a uniform speed.

[0016] In any embodiment, after encapsulation in step 3), the needle tip leaves the polyethylene wax liquid surface and is allowed to cool and solidify naturally in the air, or is slowly cooled for 1-2 minutes under an auxiliary heating environment of 50-60°C.

[0017] In any embodiment, the thickness of the polyethylene wax encapsulation layer is 5-50 μm.

[0018] The third aspect of this application also provides an application of an STM-BJ polyethylene wax-encapsulated probe, including the probe of the first aspect or the probe obtained by the preparation method of the second aspect, for use in environments containing benzene, highly polar or acid-base solvents.

[0019] The beneficial effects of this application are: 1. This invention provides a polyethylene encapsulation material for STM-BJ probes that can replace existing materials such as black wax and hafnium dioxide. This material should have excellent chemical stability (especially resistance to benzene, strong polarity and acid and alkali solvents), simple and controllable preparation process, and good insulation and performance, so as to expand the applicability and reliability of STM-BJ technology in different chemical environments.

[0020] 2. This application utilizes polyethylene wax encapsulation of the probe, which offers excellent solvent compatibility and expands the applicability of the measurement system. Traditional STM-BJ probes typically use black wax for insulating encapsulation. Black wax is a hydrocarbon-based material that undergoes significant swelling, softening, and even dissolution in polar organic solvents; this leads to the failure of the probe encapsulation layer during experiments, causing severe leakage and mechanical instability. In contrast, using polyethylene wax as the encapsulation material, a highly crystalline, non-polar polymer, whose chemical structure is incompatible with common polar solvents, exhibits strong chemical inertness. This enables stable operation in a variety of polar solvents, making it possible to study molecules that can only dissolve or function in polar solvents, greatly expanding the research boundaries of single-molecule electrical measurements.

[0021] 3. Polyethylene wax encapsulation of the probe significantly reduces background leakage current and expands the electrical window for measurement. Black wax is not only susceptible to solvents, but its material itself exhibits high ion mobility under high bias voltages or humid environments, easily generating significant background leakage current. This high background noise can drown out weak molecular conductivity signals. Furthermore, polyethylene wax has a lower dielectric constant and a denser crystalline structure, effectively suppressing ion migration and charge injection, thereby reducing background leakage current to extremely low levels. This extremely low background noise allows the system to detect molecular signals with even lower conductivity values. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating the preparation method of the STM-BJ polyethylene wax-encapsulated probe of this application. Figure 2 Experiments, encapsulated specimens, and microscopic images of the preparation method of the STM-BJ polyethylene wax-encapsulated probe of this application; Figure 3The diagram shows the dissolution of the probes encapsulated in toluene at different times using black wax (Comparative Example 1) and polyethylene wax (Example 1) of this application. Figure 4 The diagram shows the dissolution of probes encapsulated in trichlorobenzene at different times using black wax (Comparative Example 1) and polyethylene wax (Example 1) of this application. Figure 5 The diagram shows the dissolution of the probes encapsulated in trimethylbenzene at different times using black wax (Comparative Example 1) and polyethylene wax (Example 1) of this application. Figure 6 The diagram shows the dissolution of probes encapsulated with black wax (Comparative Example 1) and polyethylene wax (Example 1) in dimethyl sulfoxide at different times. Figure 7 The diagram shows the dissolution of probes encapsulated with black wax (Comparative Example 1) and polyethylene wax (Example 1) in dichloromethane at different times. Figure 8 A summary table of the applicability of black wax (Comparative Example 1) and polyethylene wax (Example 1) of this application for encapsulating probes in different solvents; Figure 9 The graphs show the molecular conductivity of the unencapsulated probe and the polyethylene wax-encapsulated probe of this application. Detailed Implementation

[0023] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the STM-BJ polyethylene wax-encapsulated probe, its preparation method, and its applications. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for a full understanding of this application by those skilled in the art and are not intended to limit the subject matter of the claims.

[0024] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0026] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0027] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0028] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0029] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0030] In one embodiment of this application, an STM-BJ polyethylene wax-encapsulated probe is provided, comprising a gold wire, the front end of which is provided with a needle tip, and the surface of the needle tip is uniformly coated with a polyethylene wax layer.

[0031] In some embodiments, the gold wire has a diameter of 0.25 mm, which provides sufficient longitudinal rigidity to prevent unnecessary lateral jitter or air disturbance during the scanning or stretching of molecules. The needle tip length is 5 mm to 15 mm, ensuring sufficient length to extend into the liquid pool without being too long to hinder experimental operation. The polyethylene wax layer encapsulation height is generally 50-70% of the needle tip length.

[0032] In some embodiments, the polyethylene wax layer encapsulation thickness is 5-50 μm.

[0033] A second aspect of this application also provides a method for preparing an STM-BJ polyethylene wax-encapsulated probe, comprising the following steps: 1) Preparation of gold needle tips: Clean the unencapsulated gold needle tips (e.g., with alcohols or organic solvents) to remove residual byproducts and avoid contamination; 2) Prepare polyethylene wax: Heat the polyethylene wax powder to above 200℃ to melt it. If the temperature is too low, the polyethylene wax will not dissolve easily. Cool and solidify it into a block at room temperature for later use. 3) Insulation encapsulation of gold needle tip: Take the polyethylene wax block from step 2) and preheat it with a temperature-controlled soldering iron until the polyethylene wax reaches a low viscosity fluid state. Generally, the temperature can be controlled at 220℃~240℃. Control the speed of the gold wire and slowly and vertically pass it through the molten polyethylene layer to form an insulating sheath layer of uniform thickness.

[0034] In needle tip encapsulation, the thickness of the encapsulation layer can be customized by precisely controlling the heating temperature and the lifting rate. The physical properties of thermoplastic polyethylene wax show that its dynamic viscosity is negatively correlated with temperature: as the heating temperature increases, the rheological properties of the molten wax increase, resulting in a thinner encapsulation layer adhering to the needle tip surface. Under constant temperature conditions, the encapsulation thickness is driven by both shear stress and surface tension; the slower the lifting speed, the more sufficient the liquid wax accumulates on the needle tip surface, thus obtaining a thicker encapsulation layer. By synergistically adjusting these parameters, different needle tips can be obtained.

[0035] In some embodiments, the preparation of the unencapsulated gold needle tip involves: immersing a gold wire in anhydrous ethanol and ultrasonically cleaning it for 5 minutes to remove surface organic contaminants; using a stainless steel needle tube nested with a gold wire as the working electrode carrier, and a gold ring as the reference and counter electrode; preparing an electrolyte solution by mixing HCl and ethanol (prepared fresh for use); then applying a constant potential of 2.2-2.8 V through an electrochemical workstation to achieve directional dissolution through anodizing; a sudden drop in current to 0 indicates that the needle tip has broken, thus obtaining the unencapsulated gold needle tip.

[0036] Preferably, the electrolyte is prepared by mixing 30-40% HCl and ethanol at a volume ratio of 0.5-1.5:1. In the electrolyte, too much HCl results in fast but rough etching; too much ethanol leads to poor conductivity and extremely slow etching. More preferably, the electrolyte is prepared by mixing 36-38% HCl and ethanol at a volume ratio of 0.8-1.2:1. In one embodiment, the electrolyte is prepared by mixing 37% HCl and ethanol at a volume ratio of 1:1. Both ethanol and concentrated hydrochloric acid are highly volatile. If left for too long, the component ratio will change, leading to unstable etching current.

[0037] At this optimized voltage, the oxidation and dissolution rate of gold is under controlled conditions. Excessive voltage (e.g., >3V) results in a violent water electrolysis reaction, producing a large amount of hydrogen / oxygen bubbles. These bubbles violently disturb the liquid surface, causing the needle tip surface to become pitted and uneven, and may even break the extremely fine needle tip. Insufficient voltage (e.g., <2V) results in an extremely slow reaction rate, causing the needle tip to be immersed in the liquid for too long, easily leading to lateral corrosion and resulting in an insufficiently sharp tip.

[0038] Under the combined effect of surface tension and electric field gradient, the neck of the gold wire preferentially dissolves, forming a conical tip. Subsequently, it is rinsed with isopropanol to remove residual byproducts and avoid contamination.

[0039] In some embodiments, the preheating temperature is 215-225°C, which causes the polyethylene wax to completely melt into a low-viscosity liquid.

[0040] At this temperature, polyethylene wax has suitable fluidity and spreadability, effectively coating the needle tip surface without decomposing or excessively volatilizing due to excessive temperature.

[0041] In some embodiments, during encapsulation in step 3), the temperature is maintained on a constant temperature heating table, and the area to be encapsulated of the fixed gold needle tip is slowly and vertically immersed into the molten polyethylene wax liquid for 3-5 seconds. Too short or too long a time will result in uneven thickness of the encapsulated needle tip. Afterward, the needle tip is vertically pulled out of the liquid surface at a uniform speed.

[0042] In some embodiments, after encapsulation in step 3), the needle tip leaves the polyethylene wax liquid surface and is allowed to cool and solidify naturally in the air, or is slowly cooled for 1-2 minutes under an auxiliary heating environment of 50-60°C.

[0043] Ultimately, a dense, smooth, and continuous polyethylene wax encapsulation layer is formed on the needle tip surface. By controlling the pulling speed and the viscosity of the molten wax, the encapsulation layer thickness can be controlled within the range of 5-50 μm.

[0044] In some embodiments, the polyethylene wax encapsulation layer has a thickness of 5-50 μm. Too thin a layer will fail to reduce leakage current, while too thick a layer will result in no conductivity.

[0045] In one embodiment of this application, an application of an STM-BJ polyethylene wax-encapsulated probe is proposed, including the above-described tip or a tip obtained by the preparation method, for use in environments containing benzene, highly polar or acid-base solvents.

[0046] Example The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0047] Example 1 A method for preparing an STM-BJ polyethylene wax-encapsulated probe includes the following steps: 1) Preparation of gold needle tips: A 0.25 mm gold wire was ultrasonically cleaned in anhydrous ethanol for 5 minutes to remove surface organic contaminants. A 25G stainless steel needle embedded with gold wire was used as the working electrode carrier, and a gold ring was used as the reference and counter electrode. An electrolyte solution (prepared fresh each time) was prepared by mixing 37% HCl and ethanol in a 1:1 volume ratio. A constant potential of 2.3 V was applied through an electrochemical workstation, and directional dissolution was achieved through an anodic oxidation reaction. The current suddenly dropped to 0, indicating that the needle tip broke, yielding an unencapsulated gold probe. The unencapsulated gold probe was rinsed with isopropanol to remove residual byproducts and avoid contamination. 2) Prepare polyethylene wax: Heat the polyethylene wax powder to around 200 ℃ to melt it, and then cool and solidify it into a block at room temperature for later use; 3) Insulation Encapsulation of Gold Needle Tips: Take the polyethylene wax block from step 2), fix the cleaned gold needle tip on a micromanipulation frame, place an appropriate amount of solid polyethylene wax block on a soldering iron, and heat it to 215-225℃ to completely melt the polyethylene wax into a low-viscosity liquid. Then, maintain the temperature on a constant-temperature heating platform, slowly and vertically immerse the area to be encapsulated of the fixed gold needle tip into the molten polyethylene wax, holding it for 3-5 seconds to ensure the needle tip surface is fully wetted and encapsulated by the molten wax. Afterward, vertically pull the needle tip out of the liquid at a uniform speed to form a uniformly thick insulating sheath layer. After the needle tip leaves the liquid surface, allow it to cool and solidify naturally in air, or slowly cool it for 1-2 minutes under auxiliary heating at 50-60℃, ultimately forming a dense, smooth, and continuous polyethylene wax encapsulation layer on the needle tip surface. The thickness of the encapsulation layer is precisely controlled within the range of 5-50 micrometers.

[0048] Comparative Example 1 In the black wax insulation encapsulation process, the black wax (ApiezonW-100) is preheated to 380 ± 10 ℃ using a temperature-controlled soldering iron (equipped with a U-shaped copper plate stage) and maintained at a constant temperature for 5 minutes to ensure that the black wax is completely converted into a low-viscosity fluid phase. Subsequently, the gold wire is slowly and uniformly passed through the molten black wax layer in a vertical direction through precise manual control. Utilizing the surface tension and rheological properties of the liquid black wax, a uniform and highly dense needle-like structure is formed on the surface of the gold wire.

[0049] Compared to traditional black wax-encapsulated probes, polyethylene wax-encapsulated probes are stable in a wide range of solvents, including aromatic hydrocarbons, thus expanding the range of solvents that can be used in STM-BJ testing. To further demonstrate the applicability of the polyethylene probe in various solution systems and its poor solubility in polar solvents compared to black wax, we immersed the encapsulated black wax probes and polyethylene probes, respectively, in equal volumes of trichlorobenzene, trimethylbenzene, dimethyl sulfoxide, and toluene. At regular intervals, we compared and analyzed the solubility of the two probes in the same solvent environments. Figure 3-7 .

[0050] The solubility of the two probes in different solvents is summarized, such as... Figure 8 It can be seen that the probes encapsulated in polyethylene wax are stable and insoluble in solvents such as toluene, trichlorobenzene, trimethylbenzene, dimethyl sulfoxide, and dichloromethane, while the probes encapsulated in black wax are only relatively stable and insoluble in dimethyl sulfoxide, and are soluble in polar solvents such as toluene, trichlorobenzene, and trimethylbenzene, and cannot exist stably. Therefore, the range of solvents that can be selected for the probes encapsulated in polyethylene wax is much wider than that for the probes encapsulated in black wax.

[0051] Single-molecule conductivity measurements of CS-C60H8 molecules were performed using STM-BJ with both unencapsulated and polyethylene wax-encapsulated probes. Figure 9As shown, at a conductivity of -4, compared with the left conductivity graph (unencapsulated probe), the leakage current of the right conductivity graph (polyethylene wax-encapsulated probe) is significantly reduced, and the molecular conductivity results are obvious. The polyethylene wax-encapsulated probe accurately achieves conductivity identification in the test.

[0052] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. An STM-BJ polyethylene wax-encapsulated probe, characterized in that, It includes a gold wire, the front end of which is provided with a needle tip, and the surface of the needle tip is uniformly covered with a polyethylene wax layer.

2. The STM-BJ polyethylene wax-encapsulated probe according to claim 1, characterized in that, The gold wire has a diameter of 0.25 mm, the needle tip length is 5 mm to 15 mm, and the polyethylene wax layer encapsulation height is generally 50-70% of the needle tip length.

3. An STM-BJ polyethylene wax-encapsulated probe according to claim 1 or 2, characterized in that, The polyethylene wax layer has a thickness of 5-50 μm.

4. A method for preparing an STM-BJ polyethylene wax-encapsulated probe, comprising the following steps: 1) Provide a cleaned probe to be encapsulated, the probe to be encapsulated comprising a gold wire and a needle tip disposed at its front end; 2) Prepare polyethylene wax blocks for later use; 3) Preheat the polyethylene wax block to a low-viscosity fluid state, control the probe tip to be vertically immersed in the molten polyethylene liquid, ensure that the surface of the tip is fully wetted and wrapped by the molten wax liquid, and then vertically pull the tip out of the molten wax liquid to form an insulating sheath layer of uniform thickness.

5. A method for preparing an STM-BJ polyethylene wax-encapsulated probe according to claim 4, characterized in that, The preparation of the probe to be encapsulated includes: immersing a gold wire in anhydrous ethanol and ultrasonically cleaning it for 5 minutes to remove surface organic contaminants; using a stainless steel needle tube nested with a gold wire as the working electrode carrier, a gold ring as the reference electrode and counter electrode, and mixing HCl and ethanol to prepare an electrolyte; then applying a constant potential of 2.2-2.8V through an electrochemical workstation to achieve directional dissolution through an anodic oxidation reaction; a sudden drop in current to 0 indicates that the gold wire has broken, yielding the gold wire and the needle tip at its tip, which is the probe to be encapsulated.

6. The method for preparing an STM-BJ polyethylene wax-encapsulated probe according to claim 4, characterized in that, The step of preheating the polyethylene wax block to a low-viscosity fluid state specifically includes: preheating the polyethylene wax block to 215-225°C, so that the polyethylene wax block is completely melted into a low-viscosity liquid.

7. The method for preparing an STM-BJ polyethylene wax-encapsulated probe according to claim 4, characterized in that, During the encapsulation process in step 3), the temperature is maintained on a constant temperature heating table. The area to be encapsulated, with the fixed gold needle tip, is slowly and vertically immersed into the molten polyethylene wax liquid and held for 3-5 seconds. After that, the needle tip is vertically pulled out of the liquid surface at a uniform speed.

8. A method for preparing an STM-BJ polyethylene wax-encapsulated probe according to claim 4 or 7, characterized in that, After encapsulation in step 3), the needle tip leaves the polyethylene wax liquid surface and is allowed to cool and solidify naturally in the air, or is slowly cooled for 1-2 minutes under an auxiliary heating environment of 50-60℃.

9. A method for preparing an STM-BJ polyethylene wax-encapsulated probe according to claim 5, characterized in that, Prepare an electrolyte solution by mixing 30-40% HCl and ethanol at a volume ratio of 0.5-1.5:

1.

10. An application of an STM-BJ polyethylene wax-encapsulated probe, comprising the probe according to any one of claims 1-3 or the probe obtained by the preparation method according to any one of claims 4-9, for use in environments containing benzene, highly polar or acid-base solvents.

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