A Raman enhancement substrate on the surface of a two-dimensional material of gold nanoparticles, and a preparation method and application thereof

Abstract

The present invention belongs to the technical field of surface Raman enhancement detection, and discloses a surface Raman enhancement substrate of gold nanoparticles on a two-dimensional material, a preparation method thereof and an application. The present invention adopts an appropriate etching process and can prepare a composite structure of gold nanoparticles and a two-dimensional material at one time. The operation method is simple and the repeatability is high. The surface Raman enhancement substrate of gold nanoparticles on a two-dimensional material prepared by the present invention can non-destructively treat the two-dimensional material, and uniform gold nanoparticles can be prepared on the surface of the two-dimensional material. During the preparation process, gold nanoparticles are also prepared while the material is peeled off. The prepared gold nanoparticles on a two-dimensional material as a surface Raman enhancement substrate has the advantages of high sensitivity, good uniformity, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface Raman enhancement detection, and particularly relates to a surface Raman enhancement substrate of gold nanoparticles and two-dimensional materials, a preparation method thereof, and an application thereof. Background Art

[0002] Surface-enhanced Raman scattering (SERS) is an advanced detection technique, and its detection ability can reach the single-molecule level. Nowadays, surface Raman enhanced scattering is widely applied in various disciplines, such as optics, photonics, surface science, solid physics, etc. At the same time, this technique has characteristics such as being real-time and fast, and can perform rapid detection.

[0003] Currently, the common Raman enhancement substrates are mainly noble metal nanoparticles, etc. However, since the enhancement effect of noble metal nanoparticles on many dye molecules is general and the fluorescence background is very large, two-dimensional materials have attracted attention in the field of surface Raman enhancement. The effect of two-dimensional materials as surface Raman enhancement substrates is usually inferior to that of noble metals, but due to their better fluorescence suppression effect than noble metals. Therefore, combining noble metals with two-dimensional materials for application in surface Raman enhancement substrates is very promising. The currently common preparation method of gold nanoparticle two-dimensional materials is electron beam evaporation into the exfoliated two-dimensional materials, and this method will cause damage to the two-dimensional materials and reduce the substrate performance. Therefore, it is very important to develop a preparation method for a gold nanoparticle two-dimensional material substrate with low destructiveness and high performance. Summary of the Invention

[0004] In order to overcome the disadvantages and deficiencies of the prior art, the primary object of the present invention is to provide a preparation method for a surface Raman enhancement substrate of gold nanoparticles and two-dimensional materials, and this method is simple, rapid, and efficient in operation.

[0005] Another object of the present invention is to provide a surface Raman enhancement substrate of gold nanoparticles and two-dimensional materials prepared by the above preparation method.

[0006] Another object of the present invention is to provide an application of the above surface Raman enhancement substrate of gold nanoparticles and two-dimensional materials.

[0007] The object of the present invention is achieved by the following technical solutions:

[0008] A preparation method for a surface Raman enhancement substrate of gold nanoparticles and two-dimensional materials, comprising the following operating steps:

[0009] (1) Cutting a silicon wafer into small pieces, cleaning and drying it, and using it as a substrate for gold nanoparticle two-dimensional materials;

[0010] (2) Placing a bulk layered two-dimensional material single crystal on an adhesive tape and repeatedly pasting it until the two-dimensional material single crystal cracks into small pieces and adheres to the adhesive tape;

[0011] (3) Fix the tape covered with two-dimensional material single crystals in step (2) on the sample stage of a vacuum evaporation instrument. Place gold grains in the furnace, then evacuate the air and deposit gold on the tape.

[0012] (4) Take out the tape after gold deposition in step (3). Stick a thermal release tape on the tape after gold deposition and press vertically, then quickly separate them to obtain a thermal release tape with a gold film and two-dimensional material attached to its surface. Then stick the thermal release tape with a gold film and two-dimensional material attached to its surface onto the silicon wafer that has been cleaned and dried in step (1).

[0013] (5) Place the silicon wafer with the thermal release tape attached obtained in step (4) on a metal heating stage and heat it. Wait for the thermal release tape to lose its adhesiveness and fall off naturally, leaving a gold film and two-dimensional material on the surface of the silicon wafer, where the two-dimensional material is covered with a gold film.

[0014] (6) Immerse the silicon wafer obtained in step (5) in an iodine / potassium iodide mixed solution, and shake the silicon wafer at the same time to etch the gold film on the surface of the two-dimensional material into nanoparticles. Take it out, and rinse the surface with alcohol and deionized water to remove the solution, obtaining a Raman enhancement substrate on the surface of the two-dimensional material with gold nanoparticles.

[0015] The cleaning in step (1) is carried out as follows: sequentially place the cut silicon wafer into acetone, ethanol, and deionized water for ultrasonic cleaning, and perform ultrasonic cleaning for 5 - 15 minutes respectively.

[0016] The two-dimensional material single crystal in step (2) is palladium diselenide, rhenium diselenide, or molybdenum disulfide.

[0017] The thickness of the gold film after gold deposition in step (3) is 80 - 120 nm.

[0018] The heating temperature in step (5) is 100 - 140 °C.

[0019] The iodine / potassium iodide mixed solution in step (6) is obtained by dissolving iodine and potassium iodide with a mass ratio of 1:4 in water, where the ratio of iodine to water is 1 g:(40 ml - 320 ml).

[0020] The soaking time of the silicon wafer in the iodine / potassium iodide mixed solution in step (6) is 30 - 90 seconds.

[0021] The temperature for soaking the silicon wafer in hot acetone in step (6) is 40 - 80 °C, and the soaking time is 10 - 20 minutes.

[0022] A Raman enhancement substrate on the surface of a two-dimensional material with gold nanoparticles prepared by the above preparation method.

[0023] Application of the above-mentioned surface Raman enhancement substrate of gold nanoparticle two-dimensional material in surface Raman enhancement detection.

[0024] Principle of the present invention:

[0025] Conventional mechanical exfoliation is difficult to obtain samples of large-size thin-layer two-dimensional materials on SiO2 / Si substrates. The method of the present invention can quickly prepare thin-layer two-dimensional materials with a gold film attached to the surface, and through an appropriate etching process, the surface gold film forms uniformly distributed gold nanoparticles, thus simply and efficiently preparing the gold nanoparticle two-dimensional material.

[0026] Since in the KI / I2 solution, I2 reacts with I - to produce I3−, and I3− undergoes a redox reaction with gold to form soluble [Au]2−. In addition, the continuous existence of excessive I3− ions makes the reaction continue, and finally, through an appropriate etching time, the gold film forms uniformly distributed nanoparticles.

[0027] In addition, due to the charge transfer between the dye molecules and the two-dimensional material, the Raman signal of the dye molecules is enhanced, and the strong local electric field generated by the gold nanoparticles also enhances the Raman signal. Therefore, the gold nanoparticle two-dimensional material prepared by this invention can not only enhance the Raman signal of the two-dimensional material itself but also detect various low-concentration dye molecules.

[0028] The present invention has the following advantages and effects compared with the prior art:

[0029] (1) The surface Raman enhancement substrate of the gold nanoparticle two-dimensional material prepared by the present invention can be non-destructive to the two-dimensional material, and uniformly distributed gold nanoparticles are prepared on the surface of the two-dimensional material. During the preparation process, gold nanoparticles are also prepared while exfoliating the material.

[0030] (2) The method used in the current technology to prepare gold nanoparticles on the surface of two-dimensional materials is complex in operation and may cause material damage, while the present invention can prepare uniformly distributed gold nanoparticles on the surface of single-layer or few-layer two-dimensional materials without damage.

[0031] (3) By using an appropriate etching process to prepare gold nanoparticles on the surface of two-dimensional materials, the operation method is simple and has extremely high repeatability. At the same time, it is also applicable to preparing uniformly distributed gold nanoparticles on the surface of other layered transition metal chalcogenides.

[0032] (4) The gold nanoparticle two-dimensional material used in the present invention as a substrate for Raman enhancement detection has the advantages of high sensitivity and good uniformity; the detection process is simple and has extremely high repeatability. When detecting fluorescent dye molecules in Raman testing, it is used as a substrate to remove or reduce the fluorescence background emitted by the dye molecules during testing. The detection limit for rhodamine 6G (R6G) molecules can reach 10 -12M can enhance the Raman signal of the PdSe2 material itself by up to 4 times its original signal. Description of the Drawings

[0033] Figure 1 is an optical microscope image of the two-dimensional material of gold nanoparticles obtained by using the etching process of the present invention, where (a) is palladium diselenide of gold nanoparticles prepared in Example 1, (b) is rhenium diselenide of gold nanoparticles prepared in Example 2, and (c) is molybdenum disulfide of gold nanoparticles prepared in Example 3.

[0034] Figure 2 is a transmission electron microscope image of the two-dimensional material of gold nanoparticles obtained by using the etching process of the present invention, where (a) is palladium diselenide of gold nanoparticles prepared in Example 1, (b) is rhenium diselenide of gold nanoparticles prepared in Example 2, and (c) is molybdenum disulfide of gold nanoparticles prepared in Example 3.

[0035] Figure 3 is the enhancement effect of gold nanoparticles on the Raman signal of the two-dimensional material itself in Example 4, where (a) is the enhancement effect on palladium diselenide, (b) is the enhancement effect on rhenium diselenide, and (c) is the enhancement effect on molybdenum disulfide.

[0036] Figure 4 is the SERS performance graph of gold nanoparticle two-dimensional materials on R6G in Example 4. Among them, (a) is the enhancement effect of palladium diselenide of gold nanoparticles on R6G, (b) is the enhancement effect of rhenium diselenide of gold nanoparticles on R6G, and (c) is the enhancement effect of molybdenum disulfide of gold nanoparticles on R6G. Detailed Embodiments

[0037] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0038] Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art. Unless otherwise stated, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the technical field.

[0039] The blue tape in the examples was purchased from Nitto Company.

[0040] Example 1 describes a method for preparing palladium diselenide of gold nanoparticles using an appropriate etching process.

[0041] (1) Cut the silicon wafer into small pieces, then sequentially place them in acetone, ethanol, and deionized water for ultrasonic cleaning, ultrasonic cleaning for 10 minutes respectively, and finally dry them with nitrogen as the substrate;

[0042] (2) Cut the blue tape into a size suitable for repeated pasting. Place the large piece of palladium diselenide on the blue tape and paste it several times to split the large piece of palladium diselenide into small pieces. Then continue to paste repeatedly until the blue tape is covered with palladium diselenide;

[0043] (3) Fix the blue tape covered with palladium diselenide in step (2) on the sample stage of a vacuum gold plating furnace. Place gold grains in the gold plating furnace and measure the thickness of the gold plating with a crystal oscillator. After setting the thickness of the gold plating layer to 100 nm, start gold plating;

[0044] (4) After the gold plating in step (3) is completed, cut the thermal release tape into the same size as the silicon wafer. Then paste the thermal release tape on the tape after gold plating and press vertically, and then quickly separate it to obtain a thermal release tape with a gold film and palladium diselenide attached to its surface; then paste the thermal release tape with a gold film and palladium diselenide attached to its surface onto the silicon wafer that has been cleaned and dried in step (1);

[0045] (5) Place the silicon wafer with the thermal release tape pasted in step (4) on a metal heating table set at a temperature of 120 °C and heat it. Wait for the thermal release tape to lose its stickiness and fall off naturally, leaving a two-dimensional palladium diselenide covered with a gold film on the surface of the silicon wafer, where the two-dimensional material is covered with a gold film;

[0046] (6) Clamp the silicon wafer obtained in step (5) with tweezers and immerse it in an iodine / potassium iodide mixed solution (the mass ratio of I2, KI, and deionized water is 1 g:4 g:160 ml) and soak it. At the same time, gently shake it for 60 s to etch the gold film on the surface of palladium diselenide into nanoparticles. Take it out and rinse it with alcohol and deionized water to remove the solution on the surface to obtain the surface Raman enhancement substrate of gold nanoparticle palladium diselenide as shown in Figure 1 (a) of the optical microscope, and Figure 2 (a) of the transmission electron microscope image shown in, and the average diameter of its gold nanoparticles is 48.6 nm.

[0047] Example 2 describes a method for preparing gold nanoparticle rhenium diselenide using an appropriate etching process.

[0048] (1) Cut the silicon wafer into small pieces, then sequentially place them in acetone, ethanol, and deionized water for ultrasonic cleaning, ultrasonic cleaning for 10 minutes respectively, and finally dry them with nitrogen as the substrate;

[0049] (2) Cut the blue tape into a size suitable for repeated pasting. Place the large piece of rhenium diselenide on the blue tape and paste it several times to split the large piece of rhenium diselenide into small pieces. Then continue to paste repeatedly until the blue tape is covered with rhenium diselenide;

[0050] (3) Fix the blue tape covered with rhenium diselenide in step (2) on the sample stage of a vacuum gold plating furnace. Place gold grains in the gold plating furnace, measure the thickness of the gold plating with a quartz crystal microbalance, and start gold plating after setting the thickness of the gold plating layer to 80 nm.

[0051] (4) After the gold plating in step (3) is completed, cut the thermal release tape into the same size as the silicon wafer, then paste the thermal release tape on the tape after gold plating and press vertically, and then quickly separate to obtain a thermal release tape with a gold film and rhenium diselenide attached to its surface; then paste the thermal release tape with a gold film and rhenium diselenide attached to its surface onto the silicon wafer that has been cleaned and dried in step (1).

[0052] (5) Place the silicon wafer with the thermal release tape pasted in step (4) on a metal heating stage set at a temperature of 100 °C and heat it. After the thermal release tape loses its adhesiveness, it will fall off naturally, leaving a two-dimensional rhenium diselenide covered with a gold film on the surface of the silicon wafer, where the two-dimensional rhenium diselenide is covered with a gold film.

[0053] (6) Clamp the silicon wafer in step (5) with tweezers and immerse it in an iodine / potassium iodide mixed solution (the mass ratio of I2, KI, and deionized water is 1 g:4 g:40 ml) and soak it. At the same time, gently shake it for 30 s, then etch the gold film on the surface of rhenium diselenide into nanoparticles, take it out, and rinse the surface with alcohol and deionized water to obtain the surface Raman enhancement substrate of gold nanoparticle palladium disulfide as shown in Figure 1 (b) of the optical microscope, and Figure 2 (b) of the transmission electron microscope image shown in, and the average diameter of its gold nanoparticles is 48.2 nm.

[0054] Example 3 describes a method for preparing gold nanoparticles molybdenum disulfide using an appropriate etching process.

[0055] (1) Cut the silicon wafer into small pieces, then sequentially place them in acetone, ethanol, and deionized water for ultrasonic cleaning for 10 minutes each, and finally blow dry with nitrogen as the substrate.

[0056] (2) Cut the blue tape into a size suitable for repeated pasting. Place the large piece of molybdenum disulfide on the blue tape and paste it several times to split the large piece of molybdenum disulfide into small pieces, and then continue to paste repeatedly until the blue tape is covered with molybdenum disulfide.

[0057] (3) Fix the blue tape covered with molybdenum disulfide in step (2) on the sample stage of a vacuum gold plating furnace. Place gold grains in the gold plating furnace, measure the thickness of the gold plating with a quartz crystal microbalance, and start gold plating after setting the thickness of the gold plating layer to 120 nm.

[0058] (4) After the gold plating is completed in step (3), cut the thermal release tape into the same size as the silicon wafer, then paste the thermal release glue on the tape after gold plating and press vertically, and then quickly separate to obtain a thermal release tape with a gold film and molybdenum disulfide attached to its surface; then paste the thermal release glue with a gold film and molybdenum disulfide attached to its surface onto the silicon wafer cleaned and dried in step (1);

[0059] (5) Place the silicon wafer with the thermal release glue obtained in step (4) on a metal heating table set at a temperature of 140 °C and heat it until the thermal release glue loses its stickiness and falls off naturally, leaving a two-dimensional molybdenum disulfide covered with a gold film on the surface of the silicon wafer, where the two-dimensional molybdenum disulfide is covered with a gold film;

[0060] (6) Hold the silicon wafer obtained in step (5) with tweezers and immerse it in an iodine / potassium iodide mixed solution (the mass ratio of I2, KI, and deionized water is 1 g:4 g:320 ml) for soaking. After gently shaking for 90 s, etch the gold film on the surface of molybdenum disulfide into nanoparticles, take it out, and rinse the surface with alcohol and deionized water to obtain the surface Raman enhancement substrate of palladium diselenide with gold nanoparticles as shown in Figure 1 (c) of the optical microscope, and Figure 2 the transmission electron microscope image shown in (c) of

[0061] Example 4 uses rhodamine 6G to perform SERS tests on gold nanoparticle two-dimensional materials.

[0062] (1) Perform Raman tests on the palladium diselenide with gold nanoparticles, rhenium diselenide with gold nanoparticles, and molybdenum disulfide with gold nanoparticles prepared in Examples 1-3 respectively, and then soak them in an iodine / potassium iodide mixed solution (the mass ratio of I2, KI, and deionized water is 1 g:4 g:40 ml) for 2 minutes to completely remove the gold nanoparticles and then perform Raman tests. As Figure 3 shown, it can be obtained that before removing the gold nanoparticles, the Raman signals of palladium diselenide, rhenium diselenide, and molybdenum disulfide are all enhanced.

[0063] (2) Prepare an aqueous solution of R6G with a concentration of 10 -6 M to 10 -12 M. Immerse the SERS substrate of palladium diselenide with gold nanoparticles in the aqueous solution of R6G with a concentration of 10 -12 M to 10 -6 M in sequence. After 30 minutes, take it out, rinse the surface with alcohol, and dry it with a nitrogen gun, and then perform surface Raman enhancement tests. The lowest detection limit of palladium diselenide with gold nanoparticles is 10 -12 M. As Figure 4 (a) in shows the Raman enhancement effect diagram of palladium diselenide with gold nanoparticles.

[0064] (3) Configuration 10 -6 M to 10 -10 An aqueous solution of R6G of M. The gold nanoparticle rhenium diselenide SERS substrate was successively immersed in 10 -10 M to 10 -6 An aqueous solution of R6G of M. After 30 minutes, it was taken out, the surface was rinsed with alcohol, dried with a nitrogen gun, and then surface Raman enhancement testing was carried out. The lowest detection limit of the gold nanoparticle rhenium diselenide was 10 -10 M, as Figure 4 In (b) is the Raman enhancement effect diagram of the gold nanoparticle rhenium diselenide.

[0065] (4) Configuration 10 -6 M to 10 -10 An aqueous solution of R6G of M. The gold nanoparticle molybdenum disulfide SERS substrate was successively immersed in 10 -10 M to 10 -6 An aqueous solution of R6G of M. After 30 minutes, it was taken out, the surface was rinsed with alcohol, dried with a nitrogen gun, and then surface Raman enhancement testing was carried out. The lowest detection limit of the gold nanoparticle molybdenum disulfide was 10 -10 M, as Figure 4 In (c) is the Raman enhancement effect diagram of the gold nanoparticle molybdenum disulfide.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A preparation method of a surface Raman enhancement substrate for two-dimensional materials of gold nanoparticles, characterized in that It includes the following operation steps: (1) Cut the silicon wafer into small pieces, clean and dry it, and use it as the substrate for the two-dimensional material of gold nanoparticles; (2) Place the bulk layered two-dimensional material single crystal on the tape and paste it repeatedly until the two-dimensional material single crystal cracks into small pieces and adheres to the tape; (3) Fix the tape covered with the two-dimensional material single crystal in step (2) on the sample stage of the vacuum evaporation instrument, put gold grains in the furnace, and then evacuate to deposit gold on the tape; (4) Take out the tape after gold deposition in step (3), paste the thermal release tape on the tape after gold deposition and press it vertically, and then quickly separate it to obtain the thermal release tape with a gold film and two-dimensional material attached to the surface; Then paste the thermal release tape with a gold film and two-dimensional material attached to the surface onto the silicon wafer cleaned and dried in step (1); (5) Place the silicon wafer pasted with the thermal release tape obtained in step (4) on a metal heating table and heat it. Wait for the thermal release tape to lose its adhesiveness and fall off naturally, leaving a gold film and two-dimensional material on the surface of the silicon wafer, where the two-dimensional material is covered with a gold film; (6) Immerse the silicon wafer obtained in step (5) in an iodine / potassium iodide mixed solution, and shake the silicon wafer at the same time to etch the gold film on the surface of the two-dimensional material into nanoparticles. Take it out, and rinse the surface with alcohol and deionized water to remove the solution on the surface, and obtain a Raman enhancement substrate on the surface of the gold nanoparticle two-dimensional material; The iodine / potassium iodide mixed solution is obtained by dissolving iodine and potassium iodide with a mass ratio of 1:4 in water, where the ratio of iodine to water is 1 g:(40 ml - 320 ml); the soaking time of the silicon wafer in the iodine / potassium iodide mixed solution is 30 - 90 seconds.

2. A method for preparing a Raman enhancement substrate on the surface of a gold nanoparticle two-dimensional material according to claim 1, wherein: The cleaning in step (1) is carried out according to the following operation: Put the cut silicon wafer into acetone, ethanol and deionized water in sequence for ultrasonic cleaning, and ultrasonically clean for 5 - 15 minutes respectively.

3. A method for preparing a Raman enhancement substrate on the surface of a gold nanoparticle two-dimensional material according to claim 1, wherein: The two-dimensional material single crystal in step (2) is palladium diselenide, rhenium diselenide or molybdenum disulfide.

4. A method for preparing a Raman enhancement substrate on the surface of a gold nanoparticle two-dimensional material according to claim 1, wherein: The thickness of the gold film after gold deposition in step (3) is 80 - 120 nm.

5. A method for preparing a Raman enhancement substrate on the surface of a gold nanoparticle two-dimensional material according to claim 1, wherein: The heating temperature in step (5) is 100 - 140 °C.

6. A Raman enhancement substrate on the surface of a gold nanoparticle two-dimensional material prepared by the preparation method according to any one of claims 1 - 5.

7. Application of the Raman enhancement substrate on the surface of the gold nanoparticle two-dimensional material according to claim 6 in surface Raman enhancement detection.

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