Multicolor electrochromic SERS (Surface Enhanced Raman Scattering) substrate as well as preparation method and application thereof
By using vanadium pentoxide nanoribbons to prepare multicolor electrochromic SERS substrates, the problems of high cost and poor stability of noble metal substrates are solved, and SERS performance regulation with low cost, high stability and precise control is achieved, which is suitable for rapid large-scale production of multicolor electrochromic SERS substrates.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HAINAN UNIV
- Filing Date
- 2026-02-11
- Publication Date
- 2026-05-12
AI Technical Summary
Existing precious metal SERS active substrates are costly, have poor stability, and have limited spectral range. Traditional preparation methods are complex and cannot precisely control SERS performance.
Vanadium pentoxide powder was used as raw material to synthesize vanadium pentoxide nanoribbons through a simple solvent treatment method. Multicolor vanadium oxide electrochromic SERS thin film substrates were then prepared on conductive glass using a spray coating process to achieve precise control of SERS performance.
The prepared multicolor electrochromic SERS substrate is low in cost, has good stability, and can be rapidly mass-produced. The SERS detection performance can be visually controlled by color changes, which solves the shortcomings of noble metal substrates and achieves precise control and high-sensitivity detection.
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Figure CN122016756A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electrochromic and surface-enhanced Raman spectroscopy detection technology, and specifically relates to a multicolor electrochromic SERS substrate, its preparation method, and its application. Background Technology
[0002] Traditional Raman spectroscopy typically yields weak signals, detectable only in solid samples and high-concentration solutions. Surface-enhanced Raman scattering (SERS), on the other hand, refers to the phenomenon where the Raman signal is significantly enhanced when target molecules adsorb onto a rough noble metal surface. Compared to traditional Raman spectroscopy, SERS can achieve a signal enhancement factor of up to 10. 12 Even higher, its detection sensitivity can reach the single-molecule level. SERS detection technology has advantages such as simple operation, high sensitivity, no need for sample pretreatment, speed, and non-destructive nature. Furthermore, SERS substrates can detect all types of analytes, including solids, liquids, and gases. As a novel and powerful spectroscopic detection technology, SERS spectroscopy is widely used in food safety testing, environmental pollutant monitoring, disease diagnosis, artifact identification, and chemical reaction analysis.
[0003] However, in existing technologies, the active substrates relied upon for SERS detection are still primarily noble metal SERS active substrates prepared mainly from traditional noble metals such as gold, silver, and copper. The enhancement effect mainly comes from the plasmon resonance of the noble metal materials within the substrate. While these noble metal SERS active substrates exhibit extremely strong enhancement effects (enhancing capabilities), they suffer from high cost, poor stability (prone to oxidation), and limited spectral range. To address the problems of traditional noble metal SERS active substrates, the use of semiconductor SERS substrates, which offer advantages such as low cost, good compatibility, tunable structure, and low susceptibility to side reactions (i.e., overcoming noble metal oxidation, i.e., good stability), has become a development trend in recent years. For example, the vanadium oxide SERS substrates currently presented are prepared using annealing or doping methods. However, annealing or doping methods for preparing vanadium oxide SERS substrates generally suffer from complex processes and the inability to precisely control SERS performance. Therefore, providing a simple method for preparing multicolor electrochromic SERS substrates that enables precise control of SERS performance is of great significance. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a multicolor electrochromic SERS substrate, its preparation method, and its applications. This method is simple and allows for precise control of SERS performance. In this preparation method, vanadium pentoxide powder is used as the raw material, and vanadium pentoxide nanoribbons are synthesized through a simple solvent treatment method. A spray coating process is then used to prepare the multicolor vanadium oxide electrochromic SERS thin film substrate. Furthermore, because the color of the multicolor electrochromic SERS substrate is strongly correlated with its SERS detection performance, color changes can be used to determine its SERS detection performance and molecular selectivity, which is of great significance for trace detection of analytes.
[0005] To address the aforementioned technical problems, this invention provides a method for preparing a multicolor electrochromic SERS substrate, comprising the following steps: Grinded vanadium pentoxide powder was added to a sodium nitrate solution and reacted at 25℃~75℃ for 5 to 15 days to obtain a vanadium pentoxide dispersion. The vanadium pentoxide dispersion was washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion. The mass ratio of vanadium pentoxide powder to sodium nitrate in the sodium nitrate solution was 1:10~20, the molar concentration of the sodium nitrate solution was 0.5mol / L~2mol / L, and the mass fraction of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 0.2%~1.0%. Vanadium pentoxide nanoribbon dispersion was uniformly sprayed onto the heated conductive glass surface. After the solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated, a vanadium pentoxide nanoribbon film was obtained, thus obtaining a multicolor electrochromic SERS substrate.
[0006] By limiting the mass ratio of vanadium pentoxide powder to sodium nitrate in the sodium nitrate solution, the molar concentration of the sodium nitrate solution, the reaction temperature of adding vanadium pentoxide powder to the sodium nitrate solution, and the reaction time of adding vanadium pentoxide powder to the sodium nitrate solution, other concentrations of sodium nitrate cannot produce vanadium oxide with a nanoribbon structure. The morphology with a nanoribbon structure may be nanorods or nanocubes.
[0007] The mass fraction of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion is limited to 0.2% to 1.0% because when the mass fraction is below 0.2%, the sprayed vanadium pentoxide nanoribbon dispersion cannot form a film on the conductive glass surface; when the mass fraction is above 1.0%, spraying processing cannot be performed, and high-quality and uniform vanadium pentoxide nanofilms cannot be prepared.
[0008] Preferably, the heating temperature of the conductive glass is 80℃~150℃, the spraying distance of the vanadium pentoxide nanoribbon dispersion to the surface of the conductive glass is 10cm~30cm, and the spraying time is 1min~5min.
[0009] The heating temperature of conductive glass is limited to 80℃~150℃ because the dispersion solvent in the vanadium pentoxide nanoribbon dispersion is water. If the heating temperature of the conductive glass is too low, the water solvent cannot evaporate to form a film. If the heating temperature of the conductive glass is too high, the conductive layer on the surface of the conductive glass (ITO glass) will fail, meaning the electrode will lose conductivity and subsequent electrochemical tests will be impossible. Only when the spraying distance and time are appropriate can a uniform and smooth film be prepared when spraying vanadium pentoxide nanofilms onto the ITO glass surface.
[0010] Preferably, the mass ratio of vanadium pentoxide powder to sodium nitrate in the sodium nitrate solution is 1:12.75.
[0011] Preferably, the molar concentration of the sodium nitrate solution is 1.5 mol / L.
[0012] Preferably, the mass fraction of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion is 0.2%.
[0013] Preferably, the aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion is 100~1000.
[0014] By limiting the aspect ratio of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion to 100~1000, the resulting multicolor electrochromic SERS substrate has a porous morphology, which is beneficial for electrolyte insertion and extraction, and improves reaction rate and color-changing performance.
[0015] Preferably, the thickness of the vanadium pentoxide nanoribbon film is 100~800 nm.
[0016] Limiting the thickness of the vanadium pentoxide nanoribbon film to 100~800nm resulted in the best electrochromic performance of the multicolor electrochromic SERS substrate. If the vanadium pentoxide nanoribbon film is too thin, the multicolor electrochromic SERS substrate has poor color-changing performance. If the vanadium pentoxide nanoribbon film is too thick, the electric field is not uniform, and the color change of the multicolor electrochromic SERS substrate is not obvious.
[0017] This invention provides a method for preparing a multicolor electrochromic SERS substrate.
[0018] Preferably, the multicolor electrochromic SERS substrate has multicolor electrochromic function under different voltages. The multicolor electrochromic SERS substrate has electrochromic and SERS effects, and can have multicolor electrochromic function under different voltages. The SERS detection performance and molecular selectivity can be judged by color change.
[0019] This invention provides the application of multicolor electrochromic SERS substrates in the identification and detection of the dye methylene blue.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention provides a method for synthesizing vanadium pentoxide nanoribbons using vanadium pentoxide powder as a raw material and sodium nitrate solution at 25℃~75℃ via a simple solvent treatment method. This is because sodium nitrate provides Na+. + By embedding V₂O₅ layers and regulating crystal growth kinetics, V₂O₅ preferentially grows along a certain crystal plane while inhibiting the growth of other crystal planes, transforming the powder into oriented one-dimensional nanoribbons. Morphology design is achieved by controlling ion intercalation and the dissolution-recrystallization balance. A multicolor electrochromic SERS substrate is prepared on conductive glass using a spray coating process. Compared to vanadium oxide SERS substrates prepared by annealing or doping, the multicolor vanadium oxide electrochromic SERS substrate prepared by the method described in this invention exhibits both electrochromic and SERS effects. Electrochromism is accompanied by changes in charge transfer, charge density, and band gap width, which significantly alter its SERS performance. Since electrochromism and the SERS effect are structurally related, altering the potential applied to the surface of a multicolor electrochromic SERS substrate can change the polarizability of the V₂O₅ nanoribbon film probe molecules and the scattering cross-section of the Raman vibrational modes. This directly affects the SERS spectral signal of the V₂O₅ nanoribbon film probe molecules, solving the problem of unadjustable SERS substrate detection performance and thus enabling precise control of SERS performance.
[0021] The preparation method provided in this invention yields a multicolor electrochromic SERS substrate that does not use heavy metals, is low in cost, and has few steps, enabling rapid and large-scale production of multicolor electrochromic SERS substrates. Furthermore, compared to noble metal SERS active substrates, this multicolor electrochromic SERS substrate, because it does not use heavy metals, avoids the side reactions of noble metal oxidation, thus exhibiting better stability.
[0022] The multicolor electrochromic SERS substrate prepared in this invention allows for precise, reversible, and visually controlled adjustment of its color, transmittance, band gap, and detection performance by changing the applied potential. The color of the multicolor electrochromic SERS substrate is strongly correlated with its SERS detection performance. The SERS enhancement performance of the substrate can be intuitively judged by observing the changes in color and optical properties during the electrochromic process. Furthermore, the reproducibility and stability of the SERS substrate can be assessed by observing the uniformity of the semiconductor film color. Attached Figure Description
[0023] Figure 1 The images shown are scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the vanadium pentoxide nanoribbon dispersion prepared in Example 1, where a is a scanning electron microscope image and b is a TEM image.
[0024] Figure 2 The infrared spectrum of the vanadium pentoxide nanoribbon dispersion prepared in Example 1 is shown.
[0025] Figure 3 The spectroelectrochemical curves of the vanadium pentoxide nanoribbon thin film prepared in Example 1 at different voltages are shown.
[0026] Figure 4 The Raman spectra of methylene blue detected by the vanadium pentoxide nanoribbon electrode prepared in Example 1 at different voltages are shown. Detailed Implementation
[0027] The specific embodiments of the present invention are described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. Unless otherwise specified, the experimental methods described in the embodiments of the present invention are conventional methods.
[0028] Electrochromism refers to the stable, continuous, and reversible changes in the optical properties (transmission, reflection, absorption) of a material under the influence of a certain applied voltage or current. It has great application potential in fields such as smart windows, anti-glare rearview mirrors, displays, and military camouflage. Semiconductors, as an important class of inorganic electrochromic materials, possess high optical contrast, excellent cycling stability, thermal stability, chemical stability, and better durability.
[0029] The charge transfer process, LSPR peak position and intensity changes, and band gap changes during the electrochromic process of semiconductor materials directly affect their SERS effect (applying different voltages to a multicolor electrochromic SERS substrate alters the substrate color, LSPR peak position, intensity changes, and band gap changes), indicating a structural correlation between semiconductor electrochromism and the SERS effect. By changing the potential applied to the surface of the semiconductor electrode material, the type, adsorption state, and redox state of the probe molecules (V₂O₅ nanoribbon film) on the active electrode substrate surface change, leading to alterations in the probe molecule polarizability and the scattering cross-section of the Raman vibrational modes. This directly affects the SERS spectral signal of the probe molecules. Therefore, utilizing the electrochromic properties of semiconductor multicolor changes to visually modulate their SERS effect is of great significance.
[0030] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in Examples 1 to 7, preferred embodiments are described to avoid redundancy. However, this invention is not limited to these, but can be implemented in other ways within the scope of the technical solutions defined in the appended claims. All raw materials, reagents, instruments, and equipment used in the following embodiments of this invention can be purchased commercially or prepared using existing methods.
[0031] The following detailed description, in conjunction with embodiments of the present invention and accompanying drawings, provides a clear and complete illustration of the technical solutions in these embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0032] Example 1 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercial vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 5g of the ground vanadium pentoxide powder was added to 500mL of sodium nitrate solution with a concentration of 1.5mol / L and reacted at 25℃ for 7 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 0.2%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 500.
[0033] (2) Preparation of multicolor electrochromic SERS substrate: 0.2% vanadium pentoxide nanoribbon dispersion was loaded into a spray gun, and then the conductive glass was heated to 120°C. The spray gun was kept 20 cm away from the conductive glass. The vanadium pentoxide nanoribbon dispersion was uniformly sprayed on the conductive glass surface for 1 min. After the solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated, a vanadium pentoxide nanoribbon film with a thickness of 100 nm was obtained, thus obtaining the multicolor electrochromic SERS substrate.
[0034] Example 2 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 2.1 g of the ground vanadium pentoxide powder was added to 500 mL of a 0.5 mol / L sodium nitrate solution and reacted at 75 °C for 5 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 0.5%. The aspect ratio of the vanadium pentoxide nanoribbons in this vanadium pentoxide nanoribbon dispersion was 100.
[0035] (2) Preparation of multicolor electrochromic SERS substrate: 0.5% vanadium pentoxide nanoribbon dispersion was loaded into a spray gun, and then the conductive glass was heated to 80°C. The spray gun was kept 10 cm away from the conductive glass, and then the vanadium pentoxide nanoribbon dispersion was uniformly sprayed on the conductive glass surface for 2 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 500 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0036] Example 3 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 5g of the ground vanadium pentoxide powder was added to 500mL of sodium nitrate solution with a concentration of 2mol / L and reacted at 50℃ for 15 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 1.0%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 1000.
[0037] (2) Preparation of multicolor electrochromic SERS substrate: A vanadium pentoxide nanoribbon dispersion with a mass fraction of 1.0% was loaded into a spray gun, and then the conductive glass was heated to 150°C. The spray gun was kept 30 cm away from the conductive glass, and then the vanadium pentoxide nanoribbon dispersion was uniformly sprayed on the conductive glass surface for 5 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 800 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0038] Example 4 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 5g of the ground vanadium pentoxide powder was added to 500mL of sodium nitrate solution with a concentration of 1.5mol / L and reacted at 25℃ for 7 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 0.2%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 500.
[0039] (2) Preparation of multicolor electrochromic SERS substrate: 0.2% vanadium pentoxide nanoribbon dispersion was loaded into a spray gun, and then the conductive glass was heated to 120°C. The spray gun was kept 20 cm away from the conductive glass. The vanadium pentoxide nanoribbon dispersion was sprayed evenly on the conductive glass surface for 1 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 100 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0040] Example 5 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 4.2 g of the ground vanadium pentoxide powder was added to 500 mL of sodium nitrate solution with a concentration of 2 mol / L and reacted at 25 °C for 7 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 0.2%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 100.
[0041] (2) Preparation of multicolor electrochromic SERS substrate: 0.2% vanadium pentoxide nanoribbon dispersion was loaded into a spray gun, and then the conductive glass was heated to 120°C. The spray gun was kept 20 cm away from the conductive glass. The vanadium pentoxide nanoribbon dispersion was uniformly sprayed on the conductive glass surface for 1 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 500 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0042] Example 6 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 5g of the ground vanadium pentoxide powder was added to 500mL of sodium nitrate solution with a concentration of 1.5mol / L and reacted at 25℃ for 7 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 1.0%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 300.
[0043] (2) Preparation of multicolor electrochromic SERS substrate: A vanadium pentoxide nanoribbon dispersion with a mass fraction of 1.0% was loaded into a spray gun, and then the conductive glass was heated to 120°C. The spray gun was kept 10 cm away from the conductive glass, and the dispersion was sprayed evenly on the surface of the conductive glass for 5 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the surface of the conductive glass evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 800 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0044] Example 7 A method for preparing a multicolor electrochromic SERS substrate includes the following steps: (1) Preparation of vanadium pentoxide nanoribbons: Commercially available vanadium pentoxide powder was ground evenly in a mortar and pestle. Then, 5g of the ground vanadium pentoxide powder was added to 500mL of sodium nitrate solution with a concentration of 1.5mol / L and reacted at 25℃ for 7 days. The solution gradually changed from yellow to reddish-brown. The vanadium pentoxide dispersion after reaction was centrifuged and washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion with a mass fraction of 0.8%. The aspect ratio of the vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 300.
[0045] (2) Preparation of multicolor electrochromic SERS substrate: 0.8% vanadium pentoxide nanoribbon dispersion was loaded into a spray gun, and then the conductive glass was heated to 150°C. The spray gun was kept 30 cm away from the conductive glass and sprayed evenly on the surface of the conductive glass for 5 min. The solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the surface of the conductive glass evaporated to obtain a vanadium pentoxide nanoribbon film with a thickness of 100 nm, thus obtaining the multicolor electrochromic SERS substrate.
[0046] Experimental verification (a) Structural confirmation (1) Electron microscopy analysis Figure 1 Scanning electron microscope (SEM) and transmission electron microscope (TEM) images of the vanadium pentoxide nanoribbon dispersion prepared in Example 1, wherein... Figure 1 In the image, 'a' represents a scanning electron microscope (SEM) image. Figure 1 In the image, b is a transmission electron microscope (TEM) image. (From...) Figure 1It can be seen that the prepared vanadium oxide exhibits a uniform, randomly oriented nanoribbon morphology with a high aspect ratio. Its diameter is in the range of 10 nm to 40 nm, and its length exceeds 20 μm.
[0047] (2) Infrared spectrum The chemical structure of the prepared vanadium pentoxide nanoribbons was characterized using infrared spectroscopy, such as... Figure 2 As shown. Located at 1570cm -1 and 3500cm -1 The characteristic peaks at 1020 cm⁻¹ are attributed to the bending and stretching vibrations of water molecules, respectively. -1 The absorption peak at 590 cm⁻¹ is attributed to the stretching vibration of V=O. -1 and 780cm -1 The characteristic peaks at these locations correspond to the symmetric and antisymmetric stretching vibration modes of VOV, respectively. Infrared spectroscopy results confirm the successful preparation of vanadium pentoxide nanoribbons.
[0048] (II) Performance Analysis (1) Characterization of electrochromic properties of multicolor electrochromic SERS substrate An electrochemical workstation coupled with a UV-Vis spectrophotometer was used to characterize the color and transmittance changes of the multicolor electrochromic SERS substrate prepared in Example 1 under different application voltages (-0.6V, -0.3V, 0.0V, 0.3V, 0.6V, and 0.9V). A square electrolytic cell was used as the electrochemical reaction vessel, a vanadium pentoxide nanoribbon electrode (multicolor electrochromic SERS substrate) as the working electrode, a platinum sheet electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 1 mol / L lithium perchlorate / propylene carbonate solution as the electrolyte. Different voltages were applied to the vanadium pentoxide electrode, and its color and transmittance changes were recorded using a UV-Vis spectrophotometer.
[0049] Figure 3 The UV-Vis absorption spectra of a multicolor electrochromic SERS substrate at different voltages are obtained by... Figure 3 It can be seen that the V₂O₅ nanoribbon film exhibits significant optical modulation characteristics in the potential range of -0.6V to +0.9V. As the applied potential increases from -0.6V to +0.9V, the transmittance of the V₂O₅ nanoribbon film decreases significantly in the wavelength range of 350nm to 550nm and increases significantly in the wavelength range of 600nm to 850nm, demonstrating its multicolor electrochromic properties.
[0050] (2) Characterization of SERS performance of multicolor electrochromic SERS substrate An electrochemical workstation coupled with a Raman spectrometer was used to characterize the SERS performance changes of the multicolor electrochromic SERS substrate prepared in Example 1 at different voltages (-1.25V, +0.6V, and +1.25V). An in-situ Raman electrolysis cell was used as the electrochemical reaction vessel, with a vanadium pentoxide nanoribbon electrode (multicolor electrochromic SERS substrate) as the working electrode, a platinum sheet electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 1 mol / L lithium perchlorate / propylene carbonate solution as the electrolyte. 10 -3 A mol / L methylene blue solution was added to an electrolytic cell. Different potentials were applied to the vanadium pentoxide nanoribbon electrode using an electrochemical workstation, and its color and transmittance at different voltages were observed. Raman spectroscopy was used to detect its effectiveness in detecting methylene blue at different color states.
[0051] Figure 4 The images show the Raman spectra of V₂O₅ nanoribbons at different voltages. Figure 4 As the voltage changes from -1.25V to +1.25V, the color of the V₂O₅ nanoribbon film on the multicolor electrochromic SERS substrate gradually changes from gray to light green and then to brick red. Its detection performance for methylene blue (MB) also gradually increases, indicating that the band gap of the V₂O₅ nanoribbon film gradually approaches the Raman excitation wavelength. These results demonstrate that the band gap of a semiconductor can be adjusted by applying an external voltage, and its SERS performance can be reversibly, precisely, and visually tunable by adjusting the color change.
[0052] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.
Claims
1. A method for preparing a multicolor electrochromic SERS substrate, characterized in that, Includes the following steps: Grinded vanadium pentoxide powder was added to a sodium nitrate solution and reacted at 25℃~75℃ for 5~15 days to obtain a vanadium pentoxide dispersion. The vanadium pentoxide dispersion was washed multiple times with deionized water to obtain a vanadium pentoxide nanoribbon dispersion. The mass ratio of vanadium pentoxide powder to sodium nitrate in the sodium nitrate solution was 1:10~20, the molar concentration of the sodium nitrate solution was 0.5mol / L~2mol / L, and the mass fraction of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion was 0.2%~1.0%. Vanadium pentoxide nanoribbon dispersion was uniformly sprayed onto the heated conductive glass surface. After the solvent in the vanadium pentoxide nanoribbon dispersion sprayed on the conductive glass surface evaporated, a vanadium pentoxide nanoribbon film was obtained, thus obtaining a multicolor electrochromic SERS substrate.
2. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The mass ratio of vanadium pentoxide powder to sodium nitrate in the sodium nitrate solution is 1:12.
75.
3. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The molar concentration of the sodium nitrate solution is 1.5 mol / L.
4. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The vanadium pentoxide nanoribbon dispersion contains 0.2% vanadium pentoxide nanoribbons by mass.
5. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The aspect ratio of vanadium pentoxide nanoribbons in the vanadium pentoxide nanoribbon dispersion is 100~1000.
6. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The thickness of the vanadium pentoxide nanoribbon film is 100~800nm.
7. The method for preparing a multicolor electrochromic SERS substrate according to claim 1, characterized in that, The heating temperature of the conductive glass is 80℃~150℃, the spraying distance of the vanadium pentoxide nanoribbon dispersion to the surface of the conductive glass is 10cm~30cm, and the spraying time is 1min~5min.
8. The multicolor electrochromic SERS substrate prepared by the method according to any one of claims 1 to 7.
9. The multicolor electrochromic SERS substrate according to claim 8, characterized in that, The multicolor electrochromic SERS substrate has electrochromic and SERS effects, and can perform multicolor electrochromic functions under different voltages. The SERS detection performance and molecular selectivity can be judged by the color change.
10. The application of the multicolor electrochromic SERS substrate according to claim 8 in the identification and detection of the dye methylene blue.