Preparation method and application of surface-enhanced Raman substrate

Abstract

The invention provides a preparation method of a surface-enhanced Raman substrate, which comprises the following steps: S1, cleaning a substrate 1 to obtain the cleaned substrate 1; s2, dissolving an organic semiconductor material in a solvent to obtain an organic semiconductor solution; s3, coating the cleaned substrate 1 with the organic semiconductor solution to obtain a substrate 2; or transferring the gold nanoparticles prepared in a self-assembly mode to the cleaned substrate 1, and then coating the substrate 1 with the organic semiconductor solution to obtain a substrate 2; and S4, drying the substrate 2 to obtain the surface-enhanced Raman substrate. A new charge transfer excitation state is formed mainly through charge resonance transition between an organic semiconductor material and to-be-detected molecules, and the polarizability of the to-be-detected molecules is changed, so that the to-be-detected molecules are more easily detected, and the purpose of enhancing Raman signals is achieved; the surface-enhanced Raman substrate is simple in preparation method and wide in application range, and can realize rapid detection of various to-be-detected substances.

Description

Technical Field

[0001] The present invention relates to the field of surface enhanced Raman substrate preparation, and mainly to a preparation method and application of a surface enhanced Raman substrate. Background Art

[0002] Raman scattering is an inelastic scattering phenomenon of photons caused by molecular vibration or rotation. However, since this phenomenon itself is very weak, researchers have developed a variety of signal enhancement techniques in the past few decades. Among these techniques, surface-enhanced Raman scattering (SERS) is widely used as a powerful analytical tool. It is a technique that enhances the Raman scattering signal of molecules by adsorbing surface molecules on a specific substrate (such as gold, silver, silicon, graphene, graphite paper, etc.) and irradiating them with specific incident light. With its high sensitivity and diversity, SERS technology plays a vital role in high-sensitivity label-free detection in the fields of materials science, biophysics, medical diagnosis and molecular biology. It has become a powerful tool for studying molecular structure and configuration, determining the symmetry of crystal structure, analyzing defects and impurities in solids, detecting environmental pollutants, studying biomolecules, and analyzing the microstructure of industrial materials.

[0003] SERS platforms are usually divided into two categories based on their basic mechanisms: one is the electromagnetic mechanism (EM) derived from localized surface plasmon resonance (LSPR), and the other is the chemical mechanism (CM) that relies on the charge transfer (CT) complex between the analyte and the substrate. Although EM-based SERS can achieve a single-molecule detection limit (10 -14 Up to 10 -15 ), but the strong Joule heating generated by light absorption at hot spots on the metal surface limits its application in biological systems that are sensitive to temperature changes. In addition, the limited formation of hot spots in the detection area leads to differences in SERS signals. The improved reproducibility mainly relies on the formation of hot spots in three-dimensional space, which is usually costly and technically demanding. Therefore, the exploration of metal-free, CM-based, and nanometal-CM composite effect-based dielectric material systems will not only help expand the SERS active platform, but also help to further clarify fundamental questions about the CM mechanism that have not been fully answered.

[0004] Organic semiconductor materials, as a new type of SERS substrate, are different from traditional metal-based, carbon-based or inorganic semiconductor SERS substrates. This type of material has a deep lowest unoccupied molecular orbitals (LUMO) energy level, which makes the molecules more receptive to electrons. The molecular structure and electronic energy level of organic semiconductor materials can be controlled by chemical modification and synthesis methods, so that the SERS performance can be adjusted and optimized according to the requirements of different application scenarios, making the Raman signal easier to detect. This shows that the SERS platform of organic semiconductor substrates has great potential. At present, SERS activity has only been established in a few materials, such as thiophene derivatives, so the potential of a wider range of organic semiconductor materials has not been fully explored. It is necessary to systematically explore the interaction between the analyte and the organic semiconductor material substrate. Creating a highly versatile organic semiconductor substrate and surface-enhanced Raman scattering of gold nanoparticles (AuNPs) and organic semiconductor composite substrates will help to deeply understand the enhancement mechanism of the SERS effect and open up new paths for the development of SERS technology.

[0005] In summary, it is necessary to develop a new technical solution to solve the defects and shortcomings in the existing technology. Summary of the invention

[0006] The present invention provides a preparation method and application of a surface enhanced Raman substrate, wherein the organic semiconductor material is uniformly coated on the substrate by spin coating, drop coating and other methods, and appropriate parameters are selected, and then the obtained surface enhanced Raman substrate is dried, and the solvent is removed by washing and other means, so that only the organic semiconductor material is on the substrate. This type of substrate mainly forms a new charge transfer excited state through the charge resonance transition between the organic semiconductor material and the molecule to be detected, thereby changing the polarizability of the molecule to be detected, making the molecule to be detected easier to detect, and achieving the purpose of Raman signal enhancement; or introducing nano-gold particles and organic semiconductor materials to compound the molecule to be detected so that the molecule to be detected obtains a stronger Raman signal. This surface enhanced Raman substrate preparation method is simple, has a wide range of applications, and can achieve rapid detection of a variety of substances to be detected.

[0007] An object of the present invention is to provide a method for preparing a surface enhanced Raman substrate, comprising the following steps:

[0008] S1, cleaning the substrate 1 to obtain a cleaned substrate 1;

[0009] S2, dissolving the organic semiconductor material in a solvent to obtain an organic semiconductor solution;

[0010] S3, applying the organic semiconductor solution to the cleaned substrate 1 to obtain a substrate 2;

[0011] or

[0012] Transferring the gold nanoparticles prepared by self-assembly to the cleaned substrate 1, and then coating the organic semiconductor solution to obtain a substrate 2;

[0013] S4, drying the substrate 2 to obtain a surface enhanced Raman substrate.

[0014] Further, the organic semiconductor material is selected from one or more of 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone (F4TCNQ), dipyrazino(2,3-f:2',3'-h)quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HATCN), 2,2'-(1,3,4,5,7,8-hexafluoro-2,6-naphthalenediylidene)bismalononitrile (F6TCNNQ), 7,7,8,8-tetracyano-p-benzoquinodimethane (TCNQ), anthraquinone (AQ), perylene diimide (PDI), (6,6)-phenylcarbonyl 61 butyric acid methyl ester (PCBM), 2,1,3-benzothiadiazole (BTH) or tetracyanoethylene (TCNE).

[0015] Figure 1 The structural formula of the organic semiconductor material is shown;

[0016] in,

[0017] Figure 1 (M1) shows the structural formula of F4TCNQ;

[0018] Figure 1 (M2) shows the structural formula of HATCN;

[0019] Figure 1 (M3) shows the structural formula of F6TCNNQ;

[0020] Figure 1 (M4) shows the structural formula of TCNQ;

[0021] Figure 1 (M5) shows the structural formula of AQ;

[0022] Figure 1 (M6) shows the structural formula of PDI;

[0023] Figure 1 (M7) shows the structural formula of PCBM;

[0024] Figure 1 (M8) shows the structural formula of BTH;

[0025] Figure 1 (M9) shows the structural formula of TCNE.

[0026] Furthermore, the concentration of the organic semiconductor solution is 1-100 g / ml.

[0027] Furthermore, the coating amount of the organic semiconductor solution is 100-200 μL.

[0028] Furthermore, the substrate 1 is selected from one or more of silicon wafer, graphite paper, anodized aluminum, carbon fiber or graphene.

[0029] Furthermore, the cleaning method includes: immersing the substrate 1 in a cleaning agent, ultrasonic cleaning, and then treating with ultraviolet ozone.

[0030] Furthermore, the cleaning agent is selected from one or more of acetone, ethanol, deionized water or piranha solution.

[0031] Furthermore, the cleaning method further comprises: cleaning the substrate 1 with dust-free paper.

[0032] Furthermore, the solvent is selected from one or more of cyclohexanone, acetonitrile, dichloromethane, n-hexane, tetrahydrofuran or petroleum ether.

[0033] Furthermore, the gold nanoparticles (AuNPs) have a particle size of 5-100 nm and a concentration of 5.47×10 13 -3.84×10 9 mL -1 .

[0034] Furthermore, the volume of the nano-gold particles is 20-100 μL.

[0035] Furthermore, in step S3, when the solution without adding nano-gold particles is adopted, the obtained substrate 2 needs to be heated and baked after drying.

[0036] Furthermore, the heating and baking temperature is 45-300° C.; the heating and baking time is 10-200 min.

[0037] Furthermore, in step S3, when the solution of adding nano-gold particles is adopted, the obtained substrate 2 needs to be cleaned with deionized water.

[0038] Furthermore, the coating is selected from one or more of spin coating, drop coating, sputtering, ion plating or evaporation.

[0039] Furthermore, when the coating is spin coating, the spin coating speed is 100-8000rpm, and the spin coating time is 5s-2min;

[0040] or,

[0041] The spin coating speed is 100-30000rpm, and the spin coating time is 5s-10min.

[0042] Another object of the present invention is to provide detection applications of a surface enhanced Raman substrate prepared by the above-mentioned method for preparing a surface enhanced Raman substrate.

[0043] The present invention has the following beneficial effects:

[0044] (1) The enhancement factor of the surface enhanced Raman substrate of the present invention is significantly higher than that of the traditional method. The present invention promotes the charge resonance transition between the substrate and the detected object by introducing organic semiconductor materials, forms a new charge transfer excited state, improves the polarizability of the detected object, and makes the Raman scattering photon yield higher, thereby greatly enhancing the intensity of the Raman signal; and the introduction of the composite of nano-gold and organic semiconductor materials can provide a large number of chemical enhancement sites, which can form a localized surface plasma resonance coupling effect. This coupling can significantly enhance the electromagnetic field, thereby further enhancing the Raman signal. At the same time, the present invention significantly enhances the Raman signal by using organic semiconductor materials, greatly reduces the detection limit, and can detect extremely low concentrations of target molecules, with extremely high sensitivity and reproducibility.

[0045] (2) Simple preparation process: The surface enhanced Raman preparation method of the present invention has simple steps, short assembly time, and is suitable for large-scale preparation. Compared with the traditional photolithography method, the method of the present invention does not require complicated equipment and processes, especially the substrate 2, which greatly reduces the production cost and time.

[0046] (3) Strong portability: The preparation method of the present invention can realize the production of portable SERS substrates, which are suitable for rapid on-site detection. Since the preparation process is simple and does not require large equipment, it can be quickly assembled and used under on-site conditions, which greatly facilitates practical applications.

[0047] (4) Good stability and uniformity: The substrate 2 used in the present invention is easy to process, has good stability and uniformity, and is suitable for large-scale applications.

[0048] (5) Wide range of applications: The SERS substrate of the present invention can be applied to complex detection environments, and its high sensitivity and high reproducibility enable it to perform well in a variety of application scenarios.

[0049] (6) Strong innovation: The present invention provides a new development direction for surface enhanced Raman technology by introducing organic semiconductor materials. This material not only improves the enhancement effect of Raman signals, but also broadens the application scope of SERS substrates.

[0050] (7) Efficient mass production: The preparation method of the present invention is suitable for efficient mass production. By optimizing the process parameters, large-scale and low-cost SERS substrate production can be achieved.

[0051] (8) Technical scalability: The method of the present invention has good technical scalability and can be adjusted and optimized according to different application requirements. For different types and structures of organic semiconductor materials, the performance of the SERS substrate can be further improved to meet different detection requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 The structural formula of the organic semiconductor material is shown;

[0053] in,

[0054] Figure 1 (M1) shows the structural formula of F4TCNQ;

[0055] Figure 1 (M2) shows the structural formula of HATCN;

[0056] Figure 1 (M3) shows the structural formula of F6TCNNQ;

[0057] Figure 1 (M4) shows the structural formula of TCNQ;

[0058] Figure 1 (M5) shows the structural formula of AQ;

[0059] Figure 1 (M6) shows the structural formula of PDI;

[0060] Figure 1 (M7) shows the structural formula of PCBM;

[0061] Figure 1 (M8) shows the structural formula of BTH;

[0062] Figure 1 (M9) shows the structural formula of TCNE.

[0063] Figure 2 The effect diagram of coating F4TCNQ, HATCN, F6TCNNQ and TCNQ materials on silicon wafer is shown; wherein,

[0064] Figure 2 (C1) shows the effect of F4TCNQ coating on silicon wafer;

[0065] Figure 2 (C2) shows the effect of HATCN coating on silicon wafer;

[0066] Figure 2 (C3) shows the effect of F6TCNNQ coating on silicon wafer;

[0067] Figure 2(C4) shows the effect of TCNQ coating on silicon wafer.

[0068] Figure 3 SEM images of Si wafer, F4TCNQ, HATCN, F6TCNNQ, and TCNQ thin films are shown;

[0069] Figure 3 (D1) shows the SEM image of the Si wafer;

[0070] Figure 3 (D2) shows the SEM image of F4TCNQ film;

[0071] Figure 3 (D3) shows the SEM image of the HATCN film;

[0072] Figure 3 (D4) shows the SEM image of F6TCNNQ film;

[0073] Figure 3 (D5) shows the SEM image of the TCNQ thin film.

[0074] Figure 4 The Raman detection image based on F4TCNQ@Si is shown;

[0075] in,

[0076] Figure 4 (1) shows a blank Raman detection image based on F4TCNQ@Si;

[0077] Figure 4 (2) shows the Raman detection image of R6G based on F4TCNQ@Si;

[0078] Figure 4 (3) shows the MB Raman detection image based on F4TCNQ@Si;

[0079] Figure 4 (4) shows the Raman detection image of NR based on F4TCNQ@Si.

[0080] Figure 5 The Raman detection image based on HATCN@Si is shown;

[0081] in,

[0082] Figure 5 (1) shows a blank Raman detection image with HATCN@Si as the substrate;

[0083] Figure 5 (2) shows the Raman detection image of R6G based on HATCN@Si;

[0084] Figure 5 (3) shows the Raman detection image of MB based on HATCN@Si;

[0085] Figure 5 (4) shows the Raman detection image of NR based on HATCN@Si.

[0086] Figure 6 The Raman detection image based on F6TCNNQ@Si is shown;

[0087] in,

[0088] Figure 6 (1) shows a blank Raman detection image based on F6TCNNQ@Si;

[0089] Figure 6 (2) shows the Raman detection image of R6G based on F6TCNNQ@Si;

[0090] Figure 6 (3) shows the MB Raman detection image based on F6TCNNQ@Si;

[0091] Figure 6 (4) shows the NR Raman detection image based on F6TCNNQ@Si.

[0092] Figure 7 The Raman detection image based on TCNQ@Si is shown;

[0093] in,

[0094] Figure 7 (1) shows a blank Raman detection image based on TCNQ@Si;

[0095] Figure 7 (2) shows the Raman detection image of R6G based on TCNQ@Si;

[0096] Figure 7 (3) shows the Raman detection image of MB based on TCNQ@Si;

[0097] Figure 7 (4) shows the Raman detection image of NR based on TCNQ@Si.

[0098] Figure 8 The Raman detection image based on AuNPs-F4TCNQ@GP is shown;

[0099] in,

[0100] Figure 8(1) shows the blank Raman detection image based on AuNPs-F4TCNQ@GP;

[0101] Figure 8 (2) shows the Raman detection image of R6G based on AuNPs-F4TCNQ@GP.

[0102] Fig. 9 The Raman detection image based on AuNPs-HATCN@GP is shown;

[0103] in,

[0104] Fig. 9 (1) shows the blank Raman detection image based on AuNPs-HATCN@GP;

[0105] Fig. 9 (2) shows the Raman detection image of R6G based on AuNPs-HATCN@GP. DETAILED DESCRIPTION

[0106] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0107] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0108] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

[0109] Example 1

[0110] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0111] S1. Soak the silicon wafer in acetone, ethanol and deionized water respectively, clean it with an ultrasonic cleaner for 15 minutes, and then clean it with plasma for 30 minutes to obtain a cleaned silicon wafer;

[0112] S2, dissolving F4TCNQ in cyclohexanone to prepare a 15 mg / ml solution to obtain an organic semiconductor solution;

[0113] S3, applying 150 μL of the organic semiconductor solution to the cleaned silicon wafer, using a spin coater, first at a rotation speed of 2000 rpm for 12 seconds, and then at a rotation speed of 3100 rpm for 20 seconds, to obtain a substrate 2;

[0114] S4. After the substrate 2 is dried, it is heated to 120° C. and baked for 30 minutes in a ventilated place using a digital heating table to obtain a surface enhanced Raman substrate.

[0115] Figure 2 The effect diagram of coating F4TCNQ, HATCN, F6TCNNQ and TCNQ materials on silicon wafer is shown;

[0116] in,

[0117] Figure 2 (C1) shows the effect of F4TCNQ coating on silicon wafer.

[0118] The effect after spin coating in this embodiment is as follows Figure 2 As shown in (C1), a very obvious film is generated on the surface of the pure silicon wafer, which is evenly distributed on the surface of the silicon wafer.

[0119] Figure 3 SEM images of Si wafer, F4TCNQ, HATCN, F6TCNNQ, and TCNQ thin films are shown;

[0120] in,

[0121] Figure 3 (D1) shows the SEM image of the Si wafer;

[0122] Figure 3 (D2) shows the SEM image of the F4TCNQ thin film.

[0123] The SEM (scanning electron microscope) microscopic morphology of the film of this embodiment is as follows Figure 3 As shown in (D2), compared with the microstructure of pure silicon wafer ( Figure 3 (D1)), a uniform and continuous film was formed on its surface.

[0124] Take the above surface enhanced Raman substrate, the test objects are R6G, MB, NR (Rhodium 6G, methylene blue, neutral red) and other dyes, and their concentrations are 10 -4 M, and perform Raman detection on it.

[0125] Figure 4 The Raman detection image based on F4TCNQ@Si is shown;

[0126] in,

[0127] Figure 4 (1) shows a blank Raman detection image based on F4TCNQ@Si;

[0128] Figure 4 (2) shows the Raman detection image of R6G based on F4TCNQ@Si;

[0129] Figure 4 (3) shows the MB Raman detection image based on F4TCNQ@Si;

[0130] Figure 4 (4) shows the Raman detection image of NR based on F4TCNQ@Si.

[0131] The Raman detection application of this embodiment is as follows Figure 4 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, integrated power: 10mW, exposure time: 10s, and integration times: 10 times, Raman test is performed on the object to be tested R6G, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 34.961au, 57.386au, and 12.149au;

[0132] Under the conditions of laser wavelength: 785nm, integrated power: 10mW, exposure time: 10s, and integration times: 10 times, the Raman test of the object MB was carried out, and the Raman signal results were normalized. It can be clearly seen that the 780cm -1 、1400cm -1 、1625cm -1 The characteristic peak enhancement intensities are 20.037au, 32.180au, and 60.801au;

[0133] Under the conditions of laser wavelength: 785nm, integrated power: 10mW, exposure time: 10s, and integration times: 10 times, Raman test was performed on the NR to be tested, and the Raman signal results were normalized. It can be clearly seen that the 764cm -1 、1383cm -1 、1570cm -1 The characteristic peak enhancement intensities are 10.101au, 28.691au, and 24.871au;

[0134] In summary, the Raman signals detected by R6G, MB, and NR dye molecules on different surface-enhanced Raman substrates are significantly enhanced.

[0135] Example 2

[0136] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0137] S1. Soak the silicon wafer in acetone, ethanol and deionized water respectively, clean it with an ultrasonic cleaner for 15 minutes, and then clean it with plasma for 30 minutes to obtain a cleaned silicon wafer;

[0138] S2, dissolving HATCN in cyclohexanone to prepare a 20 mg / ml solution to obtain an organic semiconductor solution;

[0139] S3, applying 150 μL of the organic semiconductor solution to the cleaned silicon wafer, using a spin coater, first at a rotation speed of 2100 rpm for 12 seconds, and then at a rotation speed of 3100 rpm for 20 seconds, to obtain a substrate 2;

[0140] S4. After the substrate 2 is dried, it is heated to 120° C. and baked for 30 minutes in a ventilated place using a digital heating table to obtain a surface enhanced Raman substrate.

[0141] Figure 2 (C2) shows the effect of HATCN coating on silicon wafer.

[0142] The effect after spin coating in this embodiment is as follows Figure 2 As shown in (C2), a very obvious film is generated on the surface of the pure silicon wafer, which is evenly distributed on the surface of the silicon wafer.

[0143] Figure 3 (D3) shows the SEM image of the HATCN thin film.

[0144] The SEM microstructure of the film of this example is as follows Figure 3 As shown in (D3), compared with the microstructure of pure silicon wafer ( Figure 3 (D1)), a uniform and continuous film was formed on its surface.

[0145] Take the above surface enhanced Raman substrate, the test objects are R6G, MB, NR (Rhodium 6G, methylene blue, neutral red) and other dyes, and their concentrations are 10 -4 M, and perform Raman detection on it.

[0146] Figure 5 The Raman detection image based on HATCN@Si is shown;

[0147] in,

[0148] Figure 5 (1) shows a blank Raman detection image with HATCN@Si as the substrate;

[0149] Figure 5 (2) shows the Raman detection image of R6G based on HATCN@Si;

[0150] Figure 5 (3) shows the Raman detection image of MB based on HATCN@Si;

[0151] Figure 5 (4) shows the Raman detection image of NR based on HATCN@Si.

[0152] The Raman detection application of this embodiment is as follows Figure 5 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, integrated power: 10mW, exposure time: 10s, and integration times: 10 times, Raman test is performed on the object to be tested R6G, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 23.977 au, 35.131 au, and 11.217 au;

[0153] Under the conditions of laser wavelength: 785nm, integrated power: 1mW, exposure time: 1s, and integration times: 5 times, the Raman test of the object MB was carried out, and the Raman signal results were normalized. It can be clearly seen that the 780cm -1 、1400cm -1 、1625cm -1 The characteristic peak enhancement intensities are 387.377au, 905.457au, and 809.941au;

[0154] Under the conditions of laser wavelength: 785nm, integrated power: 5mW, exposure time: 5s, and integration times: 5 times, Raman test was performed on the NR to be tested, and the Raman signal results were normalized. It can be clearly seen that the 764cm -1 、1383cm -1 、1570cm -1 The characteristic peak enhancement intensities are 8.325au, 13.783au, and 35.234au;

[0155] In summary, the Raman signals detected by R6G, MB, and NR dye molecules on different surface-enhanced Raman substrates are significantly enhanced.

[0156] Example 3

[0157] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0158] S1. Soak the silicon wafer in acetone, ethanol and deionized water respectively, clean it with an ultrasonic cleaner for 15 minutes, and then clean it with plasma for 30 minutes to obtain a cleaned silicon wafer;

[0159] S2, dissolving F6TCNNQ in cyclohexanone to prepare a 15 mg / ml solution to obtain an organic semiconductor solution;

[0160] S3, applying 150 μL of the organic semiconductor solution to the cleaned silicon wafer, using a spin coater, first at a rotation speed of 2000 rpm for 12 seconds, and then at a rotation speed of 3100 rpm for 20 seconds, to obtain a substrate 2;

[0161] S4. After the substrate 2 is dried, it is heated to 120° C. and baked for 30 minutes in a ventilated place using a digital heating table to obtain a surface enhanced Raman substrate.

[0162] Figure 2 (C3) shows the effect of F6TCNNQ coating on silicon wafer.

[0163] The effect after spin coating in this embodiment is as follows Figure 2 As shown in (C3), a very obvious film is generated on the surface of the pure silicon wafer, which is evenly distributed on the surface of the silicon wafer.

[0164] Figure 3 (D4) shows the SEM image of F6TCNNQ thin film.

[0165] The SEM microstructure of the film of this example is as follows Figure 3 As shown in (D4), compared with the microstructure of pure silicon wafer ( Figure 3 (D1)), a uniform and continuous film was formed on its surface.

[0166] Take the above surface enhanced Raman substrate, the test objects are R6G, MB, NR (Rhodium 6G, methylene blue, neutral red) and other dyes, and their concentrations are 10 -4 M, and perform Raman detection on it.

[0167] Figure 6 The Raman detection image based on F6TCNNQ@Si is shown;

[0168] in,

[0169] Figure 6 (1) shows a blank Raman detection image based on F6TCNNQ@Si;

[0170] Figure 6 (2) shows the Raman detection image of R6G based on F6TCNNQ@Si;

[0171] Figure 6 (3) shows the MB Raman detection image based on F6TCNNQ@Si;

[0172] Figure 6 (4) shows the NR Raman detection image based on F6TCNNQ@Si.

[0173] The Raman detection application of this embodiment is as follows Figure 6 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, exposure power: 10mW, exposure time: 1s, exposure times: 5 times, Raman test is performed on the object to be tested R6G, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 34.957au, 45.389au, and 38.056au;

[0174] Under the conditions of laser wavelength: 785nm, integrated power: 1mW, exposure time: 10s, and integration times: 5 times, the Raman test of the object MB was carried out, and the Raman signal results were normalized. It can be clearly seen that the 780cm -1 、1400cm -1 、1625cm -1 The characteristic peak enhancement intensities are 80.961au, 129.001au, and 106.487au;

[0175] Under the conditions of laser wavelength: 785nm, integrated power: 1mW, exposure time: 5s, and integration times: 5 times, Raman test was performed on the NR to be tested, and the Raman signal results were normalized. It can be clearly seen that the 764cm -1 、1383cm -1 、1570cm -1 The characteristic peak enhancement intensities are 56.212 au, 264.597 au, and 111.342 au;

[0176] In summary, the Raman signals detected by R6G, MB, and NR dye molecules on their different organic semiconductor substrates are significantly enhanced.

[0177] Example 4

[0178] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0179] S1. Soak the silicon wafer in acetone, ethanol and deionized water respectively, clean it with an ultrasonic cleaner for 15 minutes, and then clean it with plasma for 30 minutes to obtain a cleaned silicon wafer;

[0180] S2, dissolving TCNQ in cyclohexanone to prepare a 15 mg / ml solution to obtain an organic semiconductor solution;

[0181] S3, applying 150 μL of the organic semiconductor solution to the cleaned silicon wafer, using a spin coater, first at a rotation speed of 3100 rpm for 9 seconds, and then at a rotation speed of 4100 rpm for 30 seconds to obtain a substrate 2;

[0182] S4. After the substrate 2 is dried, it is heated to 120° C. and baked for 30 minutes in a ventilated place using a digital heating table to obtain a surface enhanced Raman substrate.

[0183] Figure 2 (C4) shows the effect of TCNQ coating on silicon wafer.

[0184] The effect after spin coating in this embodiment is as follows Figure 2 As shown in (C4), a very obvious film is generated on the surface of the pure silicon wafer, which is evenly distributed on the surface of the silicon wafer.

[0185] Figure 3 (D5) shows the SEM image of the TCNQ thin film.

[0186] The SEM microstructure of the film of this example is as follows Figure 3 As shown in (D5), compared with the microstructure of pure silicon wafer ( Figure 3 (D1)), a uniform and continuous film was formed on its surface.

[0187] Take the above surface enhanced Raman substrate, the test objects are R6G, MB, NR (Rhodium 6G, methylene blue, neutral red) and other dyes, and their concentrations are 10 -4 M, and perform Raman detection on it.

[0188] Figure 7 The Raman detection image based on TCNQ@Si is shown;

[0189] in,

[0190] Figure 7 (1) shows a blank Raman detection image based on TCNQ@Si;

[0191] Figure 7 (2) shows the Raman detection image of R6G based on TCNQ@Si;

[0192] Figure 7 (3) shows the Raman detection image of MB based on TCNQ@Si;

[0193] Figure 7 (4) shows the Raman detection image of NR based on TCNQ@Si.

[0194] The Raman detection application of this embodiment is as follows Figure 7 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, integrated power: 5mW, exposure time: 5s, and integration times: 10 times, Raman test is performed on the object R6G to be tested, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 10.282 au, 17.477 au, and 6.162 au;

[0195] Under the conditions of laser wavelength: 785nm, integrated power: 1mW, exposure time: 5s, and integration times: 5 times, the Raman test of the object MB was carried out, and the Raman signal results were normalized. It can be clearly seen that the 780cm -1 、1400cm -1 、1625cm -1 The characteristic peak enhancement intensities are 413.936 au, 928.504 au, and 1126.032 au;

[0196] Under the conditions of laser wavelength: 785nm, integrated power: 1mW, exposure time: 5s, and integration times: 5 times, Raman test was performed on the NR to be tested, and the Raman signal results were normalized. It can be clearly seen that the 764cm -1 、1383cm -1 、1570cm -1 The characteristic peak enhancement intensities are 261.578 au, 1375.670 au, and 1586.244 au;

[0197] In summary, the Raman signals detected by R6G, MB, and NR dye molecules on different surface-enhanced Raman substrates are significantly enhanced.

[0198] Example 5

[0199] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0200] S1. Wipe the graphite paper clean with dust-free paper to obtain cleaned graphite paper;

[0201] S2, dissolving F4TCNQ in cyclohexanone to prepare a 15 mg / ml solution to obtain an organic semiconductor solution;

[0202] S3, the concentration of 1.96×10 10 mL -1 50 μL of gold nanoparticles with a particle size of 65 nm were transferred to the cleaned graphite paper, and then 150 μL of the organic semiconductor solution was coated to obtain substrate 2, which was then cleaned with deionized water;

[0203] S4. After the substrate 2 is naturally dried, a surface enhanced Raman substrate is obtained.

[0204] Take the above surface enhanced Raman substrate, the object to be tested is R6G (Rhodium 6G) dye, and its concentration is 10 -4 M, and perform Raman detection on it.

[0205] Figure 8 The Raman detection image based on AuNPs-F4TCNQ@GP is shown;

[0206] in,

[0207] Figure 8 (1) shows the blank Raman detection image based on AuNPs-F4TCNQ@GP;

[0208] Figure 8 (2) shows the Raman detection image of R6G based on AuNPs-F4TCNQ@GP;

[0209] The Raman detection application of this embodiment is as follows Figure 8 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, exposure power: 0.345mW, exposure time: 1s, exposure times: 10 times, Raman test is performed on the object R6G to be tested, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 34893.266au, 71995.753au, and 8918.525au;

[0210] In summary, the Raman signal detected by R6G dye molecules on the nano-gold and organic semiconductor composite substrate is significantly enhanced.

[0211] Example 6

[0212] A method for preparing a surface enhanced Raman substrate comprises the following steps:

[0213] S1. Wipe the graphite paper clean with dust-free paper to obtain cleaned graphite paper;

[0214] S2, dissolving HATCN in cyclohexanone to prepare a 15 mg / ml solution to obtain an organic semiconductor solution;

[0215] S3, the concentration of 1.96×10 10 mL -1 50 μL of gold nanoparticles with a particle size of 65 nm were transferred to the cleaned graphite paper, and then 150 μL of the organic semiconductor solution was coated to obtain substrate 2, which was then cleaned with deionized water;

[0216] S4. After the substrate 2 is naturally dried, a surface enhanced Raman substrate is obtained.

[0217] Take the above surface enhanced Raman substrate, the object to be tested is R6G (Rhodium 6G) dye, and its concentration is 10 -4 M, and perform Raman detection on it.

[0218] Fig. 9 The Raman detection image based on AuNPs-HATCN@GP is shown;

[0219] in,

[0220] Fig. 9 (1) shows the blank Raman detection image based on AuNPs-HATCN@GP;

[0221] Fig. 9 (2) shows the Raman detection image of R6G based on AuNPs-HATCN@GP.

[0222] The Raman detection application of this embodiment is as follows Fig. 9 As shown in the figure, the test parameters are as follows: under the conditions of laser wavelength: 785nm, exposure power: 0.345mW, exposure time: 1s, exposure times: 10 times, Raman test is performed on the object R6G to be tested, and the Raman signal results are normalized. It can be clearly seen that the 612cm -1 、1510cm -1 、1650cm -1 The characteristic peak enhancement intensities are 2324.263au, 4294.247au, and 786.398au;

[0223] In summary, the Raman signal detected by R6G dye molecules on the nano-gold and organic semiconductor composite substrate is significantly enhanced.

[0224] Example 7

[0225] A method for preparing a surface enhanced Raman substrate. The difference between this embodiment and embodiment 1 is that the F4TCNQ is replaced by AQ, and the other components and preparation method are the same as those in embodiment 1.

[0226] Example 8

[0227] A method for preparing a surface enhanced Raman substrate. The difference between this embodiment and embodiment 1 is that the F4TCNQ is replaced by PDI, and the other components and preparation method are the same as those in embodiment 1.

[0228] Example 9

[0229] A method for preparing a surface enhanced Raman substrate. The difference between this embodiment and embodiment 1 is that the F4TCNQ is replaced by PCBM, and the other components and preparation method are the same as those in embodiment 1.

[0230] Example 10

[0231] A method for preparing a surface enhanced Raman substrate. The difference between this embodiment and embodiment 1 is that the F4TCNQ is replaced by BTH, and the other components and preparation method are the same as those in embodiment 1.

[0232] Embodiment 11

[0233] A method for preparing a surface enhanced Raman substrate. The difference between this embodiment and embodiment 1 is that the F4TCNQ is replaced by TCNE, and the other components and preparation method are the same as those in embodiment 1.

[0234] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0235] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for preparing a surface enhanced Raman substrate, characterized in that: The steps include: S1, cleaning the substrate 1 to obtain a cleaned substrate 1; S2, dissolving the organic semiconductor material in a solvent to obtain an organic semiconductor solution; S3, applying the organic semiconductor solution to the cleaned substrate 1 to obtain a substrate 2; or Transferring the gold nanoparticles prepared by self-assembly to the cleaned substrate 1, and then coating the organic semiconductor solution to obtain a substrate 2; S4, drying the substrate 2 to obtain a surface enhanced Raman substrate.

2. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The organic semiconductor material is selected from one or more of 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, dipyrazino(2,3-f:2',3'-h)quinoxaline-2,3,6,7,10,11-hexacarbonitrile, 2,2'-(1,3,4,5,7,8-hexafluoro-2,6-naphthalenediylidene)bismalononitrile, 7,7,8,8-tetracyano-p-benzoquinone dimethane, anthraquinone, perylene imide, (6,6)-phenylcarbonyl 61 butyric acid methyl ester, 2,1,3-benzothiadiazole or tetracyanoethylene.

3. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The concentration of the organic semiconductor solution is 1-100 g / ml.

4. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The substrate 1 is selected from one or more of silicon wafer, graphite paper, anodized aluminum, carbon fiber or graphene.

5. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The solvent is selected from one or more of cyclohexanone, acetonitrile, dichloromethane, n-hexane, tetrahydrofuran or petroleum ether.

6. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The coating is selected from one or more of spin coating, drop coating, sputtering, ion plating or evaporation.

7. The method for preparing a surface enhanced Raman substrate according to claim 1, characterized in that: The particle size of the nano-gold particles is 5-100 nm, and the concentration is 5.47×10 13 -3.84×10 9 mL -1 .

8. The method for preparing a surface enhanced Raman substrate according to claim 7, characterized in that: The volume of the gold nanoparticles is 20-100 μL.

9. Detection application of the surface enhanced Raman substrate prepared by the method for preparing the surface enhanced Raman substrate according to any one of claims 1 to 8.

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