Gold nanorod with resonant wavelength adjustable in visible-near infrared region and preparation method of gold nanorod
By controlling the concentration and time of the oxidizing agent, different parts of the gold nanorods are solved, and the problem of the complex and costly preparation of gold nanorods of different resonance wavelengths in the prior art is solved, and the preparation of gold nanorods of any wavelength in the visible-near infrared region is realized, which simplifies the preparation process and reduces the cost.
Patent Information
- Application Number
- CN202510463175.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-14
- Publication Date
- 2025-07-08
AI Technical Summary
The prior art is difficult to quickly and easily prepare gold nanorods with different resonance wavelengths, especially gold nanorods longer than the original resonance wavelengths, and the existing methods are complex and costly.
By controlling the concentration and time of the oxidant, the different parts of the gold nanorod are oxidized, and the aspect ratio is adjusted, thereby changing its resonance wavelength, and arbitrary wavelength gold nanorods in the visible-near-infrared region are prepared.
It is realized that gold nanorods with arbitrary resonance wavelengths can be obtained simply and at low cost based on existing gold nanorods, with a simple process and significant effect.
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Figure CN120269017A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of the preparation of noble metal nanomaterials, and particularly to a gold nanorod with an adjustable resonance wavelength in the visible-near infrared region and a preparation method thereof. Background Art
[0002] Due to its unique plasmonic properties, gold nanorods can generate various light-matter interactions with new mechanisms, such as plasmon-enhanced spectroscopy, high-harmonic generation, optical nanoantenna effect, plasmon-induced vacuum Rabi splitting, photothermal conversion, and plasmon-assisted photoreaction. This makes gold nanorods have important applications in many fields.
[0003] Currently, the main method for preparing gold nanorods is the seed-mediated method. Gold nanorods with different resonance wavelengths can be prepared by controlling the concentration of chemical substances in the growth solution. However, this method takes a long time and is complex. At the same time, there is a lack of a method to obtain new gold nanorods with any other resonance wavelength based on the already prepared gold nanorods, and only new gold nanorods with a resonance wavelength shorter than that of the original gold nanorods can be obtained. Summary of the Invention
[0004] In view of this, this application provides a gold nanorod with an adjustable resonance wavelength in the visible-near infrared region and a preparation method thereof. Based on the already obtained gold nanorods, this method can prepare gold nanorods with any wavelength adjustable in the visible-near infrared region, effectively overcoming the defects existing in the above-mentioned prior art.
[0005] The first aspect of this application provides a method for a gold nanorod with an adjustable resonance wavelength in the visible-near infrared region, including the following steps:
[0006] S1. Take gold nanorods and centrifuge and disperse them in cetyltrimethylammonium chloride, leave them for a period of time to obtain a dispersion;
[0007] S2. Then add an oxidant to the dispersion to obtain a mixed solution, perform an oxidation treatment at room temperature, take out the gold nanorods at different times and centrifuge and disperse them in cetyltrimethylammonium chloride to prepare new gold nanorods with a resonance wavelength shorter or longer than that of the gold nanorods.
[0008] Preferably, in step S2, when the concentration of the oxidant in the mixed solution is less than 0.8 mM, new gold nanorods with a resonance wavelength shorter than that of the gold nanorods are prepared.
[0009] Preferably, in step S2, when the concentration of the oxidant in the mixed solution is greater than 0.8 mM, new gold nanorods with a resonance wavelength longer than that of the gold nanorods are prepared.
[0010] Preferably, in step S2, the oxidant is sodium hypochlorite.
[0011] Preferably, in step S2, the specific process of taking out the gold nanorods at different times is as follows: take out the gold nanorods every 5 minutes, and take 1 mL each time.
[0012] Preferably, in step S2, the centrifugation conditions are as follows: centrifuge at a rotation speed of 8000 rmp / min for 5 minutes, and the dosage ratio of the gold nanorods to cetyltrimethylammonium chloride is 1 mL:20 mM.
[0013] Preferably, in step S1, the centrifugation conditions are as follows: centrifuge at a rotation speed of 7500 rmp / min for 15 minutes, and the dosage ratio of the gold nanorods to cetyltrimethylammonium chloride is 10 mL:20 mM.
[0014] Preferably, in step S1, the placement time is 2 hours.
[0015] Preferably, in step S1, the preparation process of the gold nanorods is as follows: synthesize the gold nanorods by the silver ion-assisted seed-mediated method, and prepare single-crystalline gold nanorods by adding silver nitrate during the growth process.
[0016] The second aspect of the present application also provides gold nanorods with adjustable resonance wavelengths in the visible-near infrared region prepared by the above method.
[0017] Compared with the prior art, the present application has the following beneficial effects:
[0018] (1) When the oxidant concentration in the present application is relatively low, the two ends of the gold nanorods are oxidized, thereby shortening the aspect ratio of the gold nanorods and regulating the wavelength to change to a shorter wavelength; when the oxidant concentration is relatively high, the sides of the gold nanorods are oxidized, increasing the aspect ratio of the gold nanorods and regulating the wavelength to change to a longer wavelength, even to the near infrared.
[0019] (2) The method of the present application has a simple process and low cost. By controlling the concentration of the oxidant, gold nanorods with any desired wavelength in the visible and near infrared regions can be obtained based on the existing gold nanorods, with high economic benefits. Description of the Drawings
[0020] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings required for the description of the present application or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.
[0021] Figure 1 (a) is the extinction spectrum of the gold nanorods, Figure 1 (b) is the scanning electron microscope picture of the gold nanorods;
[0022] Figure 2 Schematic diagram of the preparation process of gold nanorods with tunable resonance wavelengths in the visible-near infrared region;
[0023] Figure 3 is Figure 8 TEM image of the newly prepared gold nanorods labeled S1 in
[0024] Figure 4 is Figure 8 TEM image of the newly prepared gold nanorods labeled S2 in
[0025] Figure 5 is Figure 8 TEM image of the newly prepared gold nanorods labeled S3 in
[0026] Figure 6 is Figure 8 TEM image of the newly prepared gold nanorods labeled S4 in
[0027] Figure 7 is Figure 8 TEM image of the newly prepared gold nanorods labeled S5 in
[0028] Figure 8 Extinction spectrum of the newly prepared gold nanorods with resonance wavelengths longer than that of the gold nanorods in Example 5. S1-5 marked in the legend are Figures 3 - 7 extinction spectra of the newly prepared gold nanorods in the TEM images shown;
[0029] Figure 9 is Figure 8 Color photo of the colloidal solution of the newly prepared gold nanorods corresponding to the extinction spectrum;
[0030] Figure 10 is Figure 14 SEM image of the newly prepared gold nanorods labeled S1 in
[0031] Figure 11 is Figure 14 SEM image of the newly prepared gold nanorods labeled S2 in
[0032] Figure 12 is Figure 14 SEM image of the newly prepared gold nanorods labeled S3 in
[0033] Figure 13 is Figure 14 SEM image of the newly prepared gold nanorods labeled S4 in
[0034] Figure 14 Extinction spectrum of the newly prepared gold nanorods with resonance wavelengths shorter than that of the gold nanorods in Example 1. S1-4 marked in the legend are Figures 10 - 13 extinction spectra of the newly prepared gold nanorods in the SEM images shown;
[0035] Figure 15 The extinction spectra of Examples 1-5. Detailed implementation manners
[0036] To make the objectives, technical solutions and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.
[0037] The experimental methods used in the embodiments of the present application are all conventional methods unless otherwise specified.
[0038] In the following embodiments, unless otherwise specified, all raw materials can be obtained through commercial purchase or conventional methods.
[0039] Specifically, in step S1, the preparation process of the gold nanorods includes the following steps:
[0040] 1. Preparation of seeds: First, add an aqueous HAuCl4 solution (0.125 mL, 0.01 M) to a CTAB solution (5 mL, 0.1 M) in a glass vial, and mix the CTAB and HAuCl4 solutions thoroughly by inverting the vial up and down. Then, inject a freshly prepared ice-cold aqueous NaBH4 solution (0.3 mL, 0.01 M) into the vigorously stirred CTAB and HAuCl4 mixed solution, stir for 2 min to obtain a seed solution. The obtained seed solution should be placed at room temperature for more than 2 hours before use.
[0041] 2. Growth of gold nanorods: When preparing the growth solution, first add 40 mL of 0.1 M aqueous CTAB solution into a plastic tube, then successively add 2 mL of 0.01 M HAuCl4 and 0.4 mL of 0.01 M AgNO3 and mix them evenly, then add 0.8 mL of 1.0 M HCl, and then add 0.32 mL of freshly prepared 0.1 M AA solution. After mixing the obtained solution evenly, add 0.096 mL of the seed solution, and finally gently invert the reaction solution for 10 s to mix it evenly, and let it grow in a water bath at 28 °C for more than twelve hours. The synthesized gold nanorods are as Figure 1 shown Figure 1 (a) is the extinction spectrum of the gold nanorods, Figure 1 (b) is the scanning electron microscope image of the gold nanorods.
[0042] Example 1
[0043] The method for preparing gold nanorods with adjustable resonance wavelengths in the visible-near infrared region in this example includes the following steps:
[0044] S1. Take 10 mL of the prepared gold nanorods and centrifuge and disperse them in 20 mM cetyltrimethylammonium chloride. The centrifugation conditions are: centrifuge at 7500 rmp / min for 15 min, and let it stand for 2 hours to obtain a dispersion.
[0045] S2. Then add sodium hypochlorite to the dispersion to obtain a mixed solution. The concentration of sodium hypochlorite in the mixed solution is 0.2 mM. Perform oxidation treatment at room temperature. Take 1 mL of gold nanorods every 5 min and centrifuge and disperse them in 20 mM cetyltrimethylammonium chloride. The centrifugation conditions are: centrifuge at 8000 rmp / min for 5 min to prepare new gold nanorods with a resonance wavelength shorter than that of the gold nanorods.
[0046] Figure 14 The extinction spectrum of the new gold nanorods with a resonance wavelength shorter than that of the gold nanorods prepared in Example 1. In the legend, S1 - 4 marked in sequence are 1 mL of gold nanorods taken every 5 min. The TEM images corresponding to S1 - 4 are as Figures 10 - 13 shown.
[0047] Example 2
[0048] The method for preparing gold nanorods with an adjustable resonance wavelength in the visible - near - infrared region provided in this example can refer to Example 1. The difference is that the concentration of sodium hypochlorite in the mixed solution is 0.4 mM, and new gold nanorods with a resonance wavelength shorter than that of the gold nanorods are prepared.
[0049] Example 3
[0050] The method for preparing gold nanorods with an adjustable resonance wavelength in the visible - near - infrared region provided in this example can refer to Example 1. The difference is that the concentration of sodium hypochlorite in the mixed solution is 0.8 mM, and new gold nanorods with a resonance wavelength basically unchanged from that of the gold nanorods are prepared.
[0051] Example 4
[0052] The method for preparing gold nanorods with an adjustable resonance wavelength in the visible - near - infrared region provided in this example can refer to Example 1. The difference is that the concentration of sodium hypochlorite in the mixed solution is 1.6 mM, and new gold nanorods with a resonance wavelength longer than that of the gold nanorods are prepared.
[0053] Example 5
[0054] The method for preparing gold nanorods with an adjustable resonance wavelength in the visible - near - infrared region provided in this example can refer to Example 1. The difference is that the concentration of sodium hypochlorite in the mixed solution is 4 mM, and new gold nanorods with a resonance wavelength longer than that of the gold nanorods are prepared.
[0055] Figure 8The extinction spectrum of the new gold nanorods prepared in this example with a resonance wavelength longer than that of the gold nanorods. In the legend, S1-5 marked in sequence are 1 mL of gold nanorods taken every 5 minutes. The corresponding TEM images of S1-5 are as Figures 3 - 7 shown.
[0056] Test Example
[0057] The effects of adding oxidants with different concentrations to the same gold nanorods in Examples 1-5 are shown in Table 1.
[0058] Table 1
[0059] Sodium hypochlorite concentration in the mixed solution 0.2 mM 0.4 mM 0.8 mM 1.6 mM 4 mM Wavelength change during the oxidation process Blue shift Blue shift Basically unchanged Slightly red shift Significantly red shift Aspect ratio change of the gold nanorods Shorten Shorten Basically unchanged Lengthen Lengthen
[0060] As can be seen from the data in Table 1, when the concentration of the oxidant in the mixed solution exceeds 0.8 mM, new gold nanorods with a resonance wavelength longer than that of the original gold nanorods can be prepared by oxidation; when the concentration of the oxidant is less than 0.8 mM, new gold nanorods with a resonance wavelength shorter than that of the original gold nanorods can be obtained.
[0061] From Figure 1 it can be seen that the prepared initial gold nanorods are rod-shaped and have a relatively uniform morphology. At the same time, the spectrum also shows the absorption peaks of the transverse and longitudinal modes of the gold nanorods.
[0062] Figure 2 It shows the core technical solution of this application. By regulating the concentration of the oxidant, gold nanorods with any wavelength adjustable in the visible-near-infrared region can be obtained. The black line in the figure is the extinction spectrum of the prepared initial gold nanorods. By increasing the concentration of the oxidant, the initial gold nanorods become thinner and the resonance wavelength redshifts, obtaining new gold nanorods with a resonance wavelength in the near-infrared region. By decreasing the concentration of the oxidant, the initial gold nanorods shorten and the resonance wavelength blueshifts, obtaining new gold nanorods with a resonance wavelength in the visible light region.
[0063] Figures 3 - 9 It shows the TEM image, extinction spectrum and digital photo of the colloidal solution of the new gold nanorods obtained at a high oxidant concentration. These characterizations fully prove that on the basis of the prepared initial gold nanorods in this application, adding a high concentration of oxidant can obtain new gold nanorods with a resonance wavelength in the near-infrared region.
[0064] Figures 10 - 14 It shows the SEM image and extinction spectrum of the new gold nanorods obtained at a low oxidant concentration. These characterizations can prove that this application can obtain new gold nanorods with a resonance wavelength in the visible light region.
[0065] Figure 15 It shows the extinction spectra of Examples 1-5. The extinction spectra in the figure can prove the conclusions obtained in Table 1.
[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A method for gold nanorods with tunable resonance wavelengths in the visible-near infrared region, characterized in that, It includes the following steps: S1. Take gold nanorods, centrifuge and disperse them in cetyltrimethylammonium chloride, and let it stand for a period of time to obtain a dispersion; S2. Then add an oxidant to the dispersion to obtain a mixed solution, perform oxidation treatment at room temperature, take out the gold nanorods at different times and centrifuge and disperse them in cetyltrimethylammonium chloride to prepare new gold nanorods with a resonance wavelength shorter or longer than that of the gold nanorods.
2. The method of the gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, wherein In step S2, when the concentration of the oxidant in the mixed solution is less than 0.8 mM, new gold nanorods with a resonance wavelength shorter than that of the gold nanorods are prepared.
3. The method for gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S2, when the concentration of the oxidant in the mixed solution is greater than 0.8 mM, new gold nanorods with a resonance wavelength longer than that of the gold nanorods are prepared.
4. The method for gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S2, the oxidant is sodium hypochlorite.
5. The method for gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S2, the specific operation of taking out the gold nanorods at different times is: take the gold nanorods once every 5 minutes, and take 1 mL each time.
6. The method for gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S2, the centrifugation conditions are: centrifuge at a speed of 8000 rmp / min for 5 minutes, and the dosage ratio of the gold nanorods to cetyltrimethylammonium chloride is 1 mL:20 mM.
7. The method for gold nanorods with adjustable resonance wavelength in the visible-near infrared region according to claim 1, wherein In step S1, the centrifugation conditions are: centrifuge at a speed of 7500 rmp / min for 15 minutes, and the dosage ratio of the gold nanorods to cetyltrimethylammonium chloride is 10 mL:20 mM.
8. The method for gold nanorods with an adjustable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S1, the standing time is 2 hours.
9. The method for gold nanorods with tunable resonance wavelength in the visible-near infrared region according to claim 1, characterized in that, In step S1, the preparation process of the gold nanorods is: synthesize gold nanorods by the silver ion-assisted seed-mediated method, and prepare single-crystal gold nanorods by adding silver nitrate during the growth process.
10. Gold nanorods with an adjustable resonance wavelength in the visible-near-infrared region prepared by the method according to any one of claims 1-9.