Preparation method and application of diamond / two-dimensional tellurene surface-enhanced Raman substrate

Abstract

The invention relates to a preparation method of a diamond / two-dimensional tellurium ene surface-enhanced Raman substrate, which comprises the following steps: S1, respectively synthesizing a diamond film and two-dimensional tellurium ene, transferring the two-dimensional tellurium ene to the surface of the diamond film by adopting an interface self-assembly technology to form a gradient intermediate layer, and cleaning the gradient intermediate layer to obtain the diamond / two-dimensional tellurium ene surface-enhanced Raman substrate; the diamond / two-dimensional tellurene composite material is obtained; and S2, the diamond / two-dimensional tellurene composite material is soaked in a chloroauric acid aqueous solution for in-situ growth of precious metal quantum dots. The extreme physical and chemical stability of the diamond film is utilized, and the two-dimensional tellurene ensures that the SERS substrate is not influenced by the external temperature and the acid-base property in the application process, so that the stability of the SERS substrate is greatly improved; meanwhile, due to the high specific surface area and the light-substance strong coupling characteristic of the two-dimensional tellurene nanosheet, a Raman signal is enhanced; through the electromagnetic field enhancement effect of the precious metal quantum dots, the detection limit is obviously improved.

Description

Technical Field

[0001] The present invention relates to the fields of new materials and Raman spectrum enhancement technology, and in particular to a preparation method and application of a diamond / two-dimensional tellurene surface-enhanced Raman substrate. Background Art

[0002] Surface-enhanced Raman scattering (SERS) is a highly sensitive molecular detection technology with important application potential in chemical analysis, environmental monitoring, and biomedicine. The generation of SERS is inseparable from a substrate with SERS activity. Since the SERS phenomenon was first observed on a rough silver electrode, researchers have been committed to developing substrate materials with practical value. Currently, the most commonly used SERS substrate materials are precious metals such as gold and silver. However, the preparation of SERS substrates with a single precious metal material has disadvantages such as high cost, poor uniformity, and poor biocompatibility. In addition, the enhancement effect of the metal substrate is affected by the particle size and arrangement (or agglomeration), resulting in poor stability and uniformity of the substrate enhancement effect.

[0003] In recent years, researchers have been committed to using semiconductor materials as SERS substrates. Diamond, as a wide-bandgap semiconductor material with stable chemical properties, dopability, and a single Raman peak, has great potential in the field of SERS substrates. However, the intrinsic Raman activity of diamond is weak, resulting in a weak enhancement effect of a single diamond SERS substrate. Therefore, the search for a SERS substrate that combines high stability, repeatability, high sensitivity, and a wide range of applications has attracted much attention from scientific researchers. For example, Chinese patent 200910234586.7 discloses a surface-enhanced Raman substrate based on a diamond-like film modified metal nanostructure and a method for preparing the surface-enhanced Raman substrate. Although the preparation method involved is simple and easy to implement and solves the problem of easy oxidation and instability of precious metal materials, its sensitivity is still very poor. Two-dimensional semiconductor materials have become popular materials for research in the field of SERS due to their controllable valence band, atomic-level flatness, and excellent optoelectronic properties. Chinese patent 202111298896.2 discloses a single-crystal graphene / two-dimensional cuprous telluride heterojunction SERS substrate and its preparation method. Although the preparation process of the present invention is simple and has high reusability, it still has great improvements in stability and sensitivity. At the same time, the previously reported SERS substrates have a weak scope of application, complex preparation, and high cost. Therefore, it is necessary and challenging to develop a structured surface-enhanced Raman scattering substrate with good enhancement effect, stable performance, good repeatability, and simple preparation. Summary of the Invention

[0004] Based on this, it is necessary to provide a preparation method and application of diamond / two-dimensional tellurene surface-enhanced Raman substrate to address the above problems.

[0005] The method for preparing a diamond / two-dimensional tellurene surface-enhanced Raman substrate comprises the following steps:

[0006] S1, synthesizing a diamond film and two-dimensional tellurene separately, and transferring the two-dimensional tellurene to the surface of the diamond film using interfacial self-assembly technology to form a gradient intermediate layer, and then cleaning the gradient intermediate layer to obtain a diamond / two-dimensional tellurene composite material;

[0007] S2, immersing the diamond / two-dimensional tellurene composite material in an aqueous solution of chloroauric acid to in-situ grow noble metal quantum dots.

[0008] Preferably, in S1, the diamond film is prepared based on microwave plasma chemical vapor deposition, and the two-dimensional tellurene is synthesized by liquid phase hydrothermal method.

[0009] Preferably, the microwave plasma chemical vapor deposition method is to introduce hydrogen and methane as reaction gases into a microwave reaction cavity, microwaves excite the hydrogen and methane to form plasma, and deposit a high-purity diamond film on the substrate of the microwave reaction cavity.

[0010] Preferably, the flow ratio of the hydrogen and methane input into the microwave reaction chamber is 100:2-10; the microwave power range is 4000-6000W, the deposition working pressure is 18-22KPa, and the deposition time is 50-300h.

[0011] Preferably, the method for liquid-phase hydrothermal synthesis of two-dimensional tellurene is as follows: Na2TeO3 and polyvinyl pyrrolidone are dispersed in 30-50mL of pure water in a mass ratio of 1:5-10, and stirred for 60-120min to uniformly disperse the solute; then, 2-5mL of 25-28% ammonia solution as a pH regulator and 1-2.5ml of 85% hydrazine hydrate solution as a reducing agent are added to the homogeneous solution, and stirred for 20-50min; then, the solution is poured into a para-positioned high-pressure reactor, and the high-pressure reactor is placed in an oven and the temperature is set to react for a certain time to obtain the desired two-dimensional tellurene solution.

[0012] Preferably, the reaction temperature in the oven is 120-180° C., the reaction time is 3-6 h, and the heating rate is 5-10° C. / min.

[0013] Preferably, the cleaning and transfer method of the two-dimensional tellurene solution is as follows: take 1 mL of the two-dimensional tellurene solution, add pure water to 4 mL, ultrasonically clean, place it in a centrifuge for centrifugation, aspirate the supernatant into a waste liquid bucket, retain the precipitate, and then repeat the above cleaning process using acetone / toluene / isopropanol solution; add 4 mL of pure water to the precipitate obtained after cleaning, let it stand for 3 to 24 hours, and the two-dimensional tellurene flakes float on the surface of the solution under the action of buoyancy; pick up the floating two-dimensional tellurene flakes and place them on the diamond film substrate, and then clean and dry them.

[0014] Preferably, the centrifuge speed is 3000-8000 r / min, the centrifugation time is 5-30 min, the cleaning process is cleaning with pure water, acetone, toluene, and isopropanol solution in sequence, the single cleaning time is 5-20 min, and the drying temperature is 60-80°C.

[0015] Preferably, the concentration of the chloroauric acid aqueous solution is 3 to 10 mmol / L, and the immersion time is 10 seconds to 20 minutes.

[0016] The preparation method of diamond / two-dimensional tellurene surface-enhanced Raman substrate is applied to surface-enhanced Raman scattering measurement of materials.

[0017] The benefits of the present invention are as follows: 1. By utilizing the extreme physical and chemical stability of diamond films, the two-dimensional tellurene ensures that the SERS substrate is not affected by external temperature and acidity during application, greatly improving the stability of the SERS substrate; at the same time, the two-dimensional tellurene nanosheets enhance the Raman signal due to their high specific surface area and strong light-matter coupling characteristics; and the electromagnetic field enhancement effect of the noble metal quantum dots significantly improves the detection limit. In summary, the present invention achieves a high sensitivity (detection limit of 10 -15 mol / L), stability (signal attenuation <1% under high temperature acid-base environment) and biocompatibility are synergistically improved, and it can be widely used in trace drug detection, in-situ monitoring of high-temperature industrial processes and early biomedical diagnosis.

[0018] 2. The present invention provides a preparation method for a diamond / two-dimensional tellurene surface-enhanced Raman substrate, which has simple preparation process conditions, low cost, convenient operation, can be industrialized, and has great commercial value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the process of the present invention;

[0020] Figure 2are SEM images of the present invention; wherein, (a) and (b) are SEM images of diamond / 2DTe / Au-1 prepared in Example 1, (c) and (d) are SEM images of diamond / 2D Te / Au-5 obtained in Example 1, and (e) and (f) are SEM images of diamond / 2D Te / Au-10 obtained in Example 1;

[0021] Figure 3 TEM image of diamond / 2D Te / Au-5 prepared in Example 2;

[0022] Figure 4 These are the Raman patterns of diamond, diamond / 2D Te, diamond / 2D Te / Au-1 obtained in Example 1, and diamond / 2D Te / Au-5 and diamond / 2D Te / Au-10 obtained in Example 2;

[0023] Figure 5 The SERS performance graphs of diamond / 2D Te / Au-5 obtained in Example 2 at various concentrations of Rhodamine 6G (R6G) in a conventional environment;

[0024] Figure 6 The SERS performance diagram of diamond / 2D Te / Au-5 R6G in acidic and alkaline environments obtained in Example 2, (a) is in an environment with pH = 1, and (b) is in an environment with pH = 13;

[0025] Figure 7 This is the SERS performance diagram of diamond / 2D Te / Au-5 in a high temperature environment obtained in Example 2;

[0026] Figure 8 This is the SERS performance diagram of uric acid molecules (UA) in deionized water environment of diamond / 2D Te / Au-5 obtained in Example 2;

[0027] Figure 9 This is the SERS performance diagram of diamond / 2D Te / Au-5 obtained in Example 2 for uric acid molecules (UA) in a urine environment. DETAILED DESCRIPTION

[0028] To make the above-mentioned objects, features, and advantages of the present invention more readily apparent, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. The following description sets forth numerous specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art may make similar modifications without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0029] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention pertains. The terms used herein in the specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] A method for preparing a diamond / two-dimensional tellurene (2D Te) surface-enhanced Raman substrate comprises the following steps:

[0032] S1, respectively synthesize diamond film and two-dimensional tellurene, and transfer the two-dimensional tellurene to the surface of the diamond film by interfacial self-assembly technology to form a gradient intermediate layer, and then clean the gradient intermediate layer to obtain a diamond / two-dimensional tellurene composite material. Specifically, the diamond film can be prepared by chemical vapor deposition (CVD) or physical vapor deposition (PVD) or high temperature and high pressure method (HPHT), and the two-dimensional tellurene (2D Te) can be generated by liquid phase hydrothermal synthesis or vapor phase deposition. Interfacial self-assembly technology is an advanced manufacturing method in which molecules, nanoparticles and other primitives are spontaneously arranged in an orderly manner at a specific interface (such as liquid-liquid, liquid-solid, gas-liquid) to form a functional structure. The two-dimensional tellurene is transferred to the surface of the diamond film by interfacial self-assembly technology to form a gradient intermediate layer, and then cleaned to obtain a diamond / two-dimensional tellurene (diamond / 2DTe) composite material. Furthermore, the cleaning method is as follows: alcohol, deionized water and an organic solvent are used to alternately clean the diamond / 2D Te composite material.

[0033] S2, immersing the diamond / two-dimensional tellurene composite material in a chloroauric acid (HAuCl4·4H2O) aqueous solution to in-situ grow precious metal quantum dots. Specifically, this process utilizes the surface chemical properties of two-dimensional tellurene, especially its significant surface polarity and electron donor ability, to achieve efficient capture and controllable reduction deposition of precious metal ions. This reaction mainly depends on the electron donor properties, surface polarity and reaction of the 2D Te material with AuCl4 - Charge interaction of ions. Due to its low-dimensional structure and highly asymmetric surface electron distribution, two-dimensional tellurene materials exhibit significant surface polarity characteristics, especially at edge sites, defect sites and the interface with the diamond substrate, forming localized charge unevenness. This surface polarity effectively enhances the absorption of metal precursor ions (such as AuCl4 - ) adsorption capacity, promoting its local enrichment on the tellurene surface, thereby increasing the kinetic rate of electron transfer. In the process of reacting with HAuCl4 aqueous solution, the Te atoms on the 2D Te surface act as electron donors to transfer Au 3+ Reduction to metallic Au 0 In this process, the surface polarity accelerates the series of steps of ion adsorption-reduction-nucleation, which is conducive to the formation of gold nanoclusters with uniform particle size and stable distribution. At the same time, Te atoms may be partially oxidized to Te 4+ , introducing a small amount of interfacial charge reconstruction to further regulate the local reaction microenvironment.

[0034] Furthermore, in the present embodiment, the S1 prepares the diamond film based on microwave plasma chemical vapor deposition, and synthesizes the two-dimensional tellurene by liquid phase hydrothermal method.

[0035] Furthermore, in this embodiment, the microwave plasma chemical vapor deposition method uses hydrogen and methane as reaction gases to be introduced into a microwave reaction cavity, microwaves excite hydrogen and methane to form plasma, and deposit a high-purity diamond film on the base of the microwave reaction cavity. The thickness of the deposited diamond film is 0.5 to 3 mm.

[0036] Furthermore, in this embodiment, the flow ratio of the hydrogen and methane input into the microwave reaction chamber is 100:2-10; the microwave power range is 4000-6000W, the deposition working pressure is 18-22KPa, and the deposition time is 50-300h.

[0037] Furthermore, in this embodiment, the method for liquid-phase hydrothermal synthesis of two-dimensional tellurene is as follows: Na2TeO3 and polyvinyl pyrrolidone (PVP) are dispersed in 30-50ml of pure water in a mass ratio of 1:5-10, and stirred for 60-120min to uniformly disperse Na2TeO3 and polyvinyl pyrrolidone (PVP) in the pure water; then, 2-5mL of 25-28% ammonia solution as a pH regulator and 1-2.5ml of 85% hydrazine hydrate solution as a reducing agent are added to the homogeneous solution in sequence, and stirred for 20-50min; the solution is then poured into a para-positioned autoclave, which is made of polyphenol with strong corrosion resistance and embedded in a stainless steel sleeve to enhance structural strength. The autoclave is then placed in an oven and set at a set temperature for a certain time to obtain the desired two-dimensional tellurene solution.

[0038] Furthermore, in this embodiment, the reaction temperature in the oven is 120-180° C., the reaction time is 3-6 h, and the heating rate is 5-10° C. / min.

[0039] Furthermore, in this embodiment, the cleaning and transfer method of the two-dimensional tellurene solution is as follows: take 1 mL of the two-dimensional tellurene solution, add pure water to 4 mL, ultrasonically clean, put it into a centrifuge for centrifugation, aspirate the supernatant into a waste liquid bucket, retain the precipitate, and then repeat the above cleaning process with acetone / toluene / isopropanol solution; add 4 mL of pure water to the precipitate obtained after cleaning, let it stand for 3 to 24 hours, and the two-dimensional tellurene flakes float on the surface of the solution under the action of buoyancy; pick up the floating two-dimensional tellurene flakes and place them on the diamond film substrate, and then clean and dry them.

[0040] Furthermore, in this embodiment, the centrifuge speed is 3000-8000 r / min, the centrifugation time is 5-30 min, the cleaning process is cleaning with pure water, acetone, toluene, and isopropanol solution in sequence, the single cleaning time is 5-20 min, and the drying temperature is 60-80°C.

[0041] Furthermore, in this embodiment, the concentration of the chloroauric acid aqueous solution is 3 to 10 mmol / L, and the immersion time is 10 s to 20 min.

[0042] Example 1

[0043] The preparation method of diamond / two-dimensional tellurene surface-enhanced Raman substrate is specifically implemented with reference to the following steps and parameters:

[0044] A 0.5mm-thick diamond film was grown on a diamond substrate using microwave plasma chemical vapor deposition. The hydrogen and methane flow ratio was 100:2, the microwave power was 5000W, the deposition pressure was 20kPa, and the deposition time was 100h. Polishing was used to reduce the roughness of the diamond film substrate to less than 5nm. The liquid-phase hydrothermal synthesis of two-dimensional tellurene involved the following steps: 0.0665g of Na2TeO3 and 0.665g of polyvinylpyrrolidone (PVP) with an average molecular weight of 58K were dispersed in 50mL of pure water and stirred for 60 minutes to ensure uniform solute dispersion. Subsequently, 2.2 mL of ammonia solution (25 wt.%) as a pH adjuster and 1.1 mL of hydrazine hydrate solution (85 wt.%) as a reducing agent were added to the homogeneous solution, and stirred for 30 minutes. The solution was then poured into a 50 mL para-polyphenol autoclave and embedded in a stainless steel sleeve. The autoclave was then placed in an oven (heating rate of 5°C / min) and reacted at 180°C for 6 hours to obtain the desired 2D Te solution. The synthesized 2D Te material was cleaned and uniformly transferred to the diamond surface using interfacial self-assembly technology to form a gradient intermediate layer. The specific method was as follows: 1 mL of 2D Te solution was added to 4 mL of acetone (purified water). After ultrasonic cleaning, the solution was centrifuged at 8000 rpm for 10 minutes. The supernatant was then aspirated into a waste liquid bucket, the precipitate was retained, and the cleaning process was repeated after adding purified water. The precipitate obtained after cleaning was added to 4 mL of purified water and allowed to stand for 1 hour. The buoyancy of the thinner 2D Te flakes floated to the surface of the solution. The floated 2D Te flakes were scooped up and placed on the target substrate and dried. The 2D Te flakes / diamond substrate were further washed with purified water, acetone, toluene, and isopropanol for 10 minutes each, and then dried at 80°C.

[0045] Step 2: In situ growth of noble metal quantum dots was performed by immersing the diamond / 2D Te composite material in a HAuCl4·4H2O aqueous solution for 1 min to obtain diamond / 2D Te / Au-1.

[0046] Reference Figure 2, where (a) and (b) are SEM images of diamond / 2D Te / Au-1 prepared in this example, (c) and (d) are SEM images of diamond / 2D Te / Au-5 obtained in this example, and (e) and (f) are SEM images of diamond / 2D Te / Au-10 obtained in this example. It can be found that diamond / 2DTe / Au-1 has relatively sparse Au quantum dots, diamond / 2DTe / Au-5 has relatively dense Au quantum dots, and they are not connected together, which is sufficient to form relatively dense SERS hotspots. The Au quantum dots in diamond / 2DTe / Au-10 are completely covered, resulting in a weakening of the SERS hotspot.

[0047] Example 2

[0048] This example differs from Example 1 in that the flow ratio of hydrogen to methane in step 1 is 100:4, and the reaction time in step 2 is 5 minutes. The remaining steps are the same as in Example 1. The resulting sample is diamond / 2DTe / Au-5.

[0049] Figure 4 The Raman patterns of diamond, diamond / 2D Te, diamond / 2D Te / Au-1 obtained in Example 1, diamond / 2D Te / Au-5, and diamond / 2D Te / Au-10 obtained in Example 2; 1332 cm -1 The Raman characteristic peak of diamond is 50-150cm -1 is the Raman characteristic peak of 2D Te. After the Au quantum dots are grown, the Raman characteristic peak of 2D Te disappears, which is mainly due to the strong charge transfer between Au and 2D Te.

[0050] Example 3

[0051] This example differs from Example 1 in that the diamond growth time in step 1 is 70 hours, and the growth thickness is 0.4 mm; and the reaction time in step 2 is 10 minutes. The remaining steps are the same as in Example 1. The resulting sample is diamond / 2D Te / Au-10.

[0052] Example 4

[0053] In this embodiment, a preparation method based on a diamond / two-dimensional tellurene surface-enhanced Raman substrate is applied to surface-enhanced Raman scattering measurement of materials.

[0054] The prepared diamond / two-dimensional tellurene surface-enhanced Raman substrate was used for surface-enhanced Raman scattering measurements of R6G, acid-base environment response, in-situ high temperature and uric acid samples in sequence: First, 1mM R6G stock solution was prepared in anhydrous ethanol and diluted step by step to 10-8M, 10-10M, 10-12M, 10-13M, 10-14M, 10-16M, 10-17M, 10-18M, 10-20M, 10-21M, 10-22M, 10-23M, 10-24M, 10-25M, 10-26M, 10-27M, 10-28M, 10-29M, 10-30M, 10-31M, 10-32M, 10-3 -15 M; 5 μL of R6G solution of each concentration was dropped onto the substrate surface, and after natural adsorption for 30 minutes, it was placed in a 60℃ oven for drying for 5 minutes. After drying, Raman testing was performed using a 533nm laser (power 0.2 mW, integration time 1 s, spot diameter approximately 1 μm); then, the substrate was immersed in pH1 and pH13 buffer solutions (immersion for 5 minutes, 60 minutes, 180 minutes, 360 minutes, 720 minutes, and 1440 minutes), taken out, rinsed with pure water, and blown dry, and then 5 μL of the test molecule solution was dropped. After drying, the Raman signal was immediately measured; then, the added and dried substrate was fixed on an in-situ controllable temperature heating stage, and the temperature was programmed to 50℃, 100℃, 150℃, 200℃, and 300℃, and each temperature platform was maintained for 2 minutes. The same laser parameters were used for scanning on each platform; finally, uric acid molecules were dissolved in artificial urine and deionized water, and Raman measurements were completed using the same laser parameters. In this experiment, each test was repeated ≥3 times, and the average value was taken and the RSD was calculated to verify the enhanced performance and stability of the substrate in different molecules, pH and temperature and complex matrices.

[0055] The above-described embodiments merely illustrate several implementations of the present invention, and while their descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make numerous variations and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a diamond / two-dimensional tellurene surface-enhanced Raman substrate, characterized in that: The following steps are included: S1, synthesizing a diamond film and two-dimensional tellurene separately, and transferring the two-dimensional tellurene to the surface of the diamond film using interfacial self-assembly technology to form a gradient intermediate layer, and then cleaning the gradient intermediate layer to obtain a diamond / two-dimensional tellurene composite material; S2, immersing the diamond / two-dimensional tellurene composite material in an aqueous solution of chloroauric acid to in-situ grow noble metal quantum dots.

2. The preparation method according to claim 1, wherein: Said S1, prepares the diamond film based on microwave plasma chemical vapor deposition method, and synthesizes the two-dimensional tellurene by liquid phase hydrothermal method.

3. The preparation method according to claim 2, wherein: The microwave plasma chemical vapor deposition method uses hydrogen and methane as reaction gases to pass into a microwave reaction cavity, microwaves excite the hydrogen and methane to form plasma, and deposit a high-purity diamond film on the base of the microwave reaction cavity.

4. The preparation method according to claim 3, wherein: The flow ratio of the hydrogen and methane input into the microwave reaction chamber is 100:2-10; the microwave power range is 4000-6000W, the deposition working pressure is 18-22KPa, and the deposition time is 50-300h.

5. The preparation method according to claim 2, wherein: The liquid-phase hydrothermal synthesis method of two-dimensional tellurene is as follows: Na2TeO3 and polyvinyl pyrrolidone are dispersed in 30-50 ml of pure water at a mass ratio of 1:5-10, and stirred for 60-120 minutes to uniformly disperse the solute; then, 2-5 ml of a 25-28% ammonia solution as a pH regulator and 1-2.5 ml of an 85% hydrazine hydrate solution as a reducing agent are added to the homogeneous solution, and stirred for 20-50 minutes; the solution is then poured into a para-positioned high-pressure reactor, and the high-pressure reactor is placed in an oven at a set temperature for reaction for a certain time to obtain the desired two-dimensional tellurene solution.

6. The preparation method according to claim 5, wherein: The reaction temperature in the oven is 120-180° C., the reaction time is 3-6 hours, and the heating rate is 5-10° C. / min.

7. The preparation method according to claim 5, wherein: The cleaning and transfer method of the two-dimensional tellurene solution is as follows: take 1 mL of the two-dimensional tellurene solution, add pure water to 4 mL, ultrasonically clean, place it in a centrifuge for centrifugation, aspirate the supernatant into a waste liquid bucket, retain the precipitate, and then repeat the above cleaning process using acetone / toluene / isopropanol solution; add 4 mL of pure water to the precipitate obtained after cleaning, let it stand for 3 to 24 hours, and the two-dimensional tellurene flakes float on the surface of the solution under the action of buoyancy; pick up the floating two-dimensional tellurene flakes and place them on the diamond film substrate, and then clean and dry them.

8. The preparation method according to claim 7, wherein: The centrifuge speed is 3000-8000 r / min, the centrifugation time is 5-30 min, the cleaning process is cleaning with pure water, acetone, toluene, and isopropyl alcohol solution in sequence, the single cleaning time is 5-20 min, and the drying temperature is 60-80°C.

9. The preparation method according to claim 1, wherein: The concentration of the chloroauric acid aqueous solution is 3 to 10 mmol / L, and the soaking time is 10 seconds to 20 minutes.

10. The preparation method according to any one of claims 1 to 9 is applied to surface enhanced Raman scattering measurement of materials.

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