CN113406055B - Preparation method of twice-reduced tin-silver dendritic nanostructures with enhanced Raman spectroscopy - Google Patents

Abstract

The present application relates to a method for preparing a Raman spectrum-enhanced secondary-reduced tin-silver dendrite nanostructure, and specifically relates to the field of preparation of a dendrite nanostructure. In the preparation method provided by this application, the preset substrate is placed in the tin protochloride-ethanol solution to react for the first preset time to obtain the tin dendrite nanostructure, and under the condition of avoiding light, the tin dendrite nanostructure is placed on react in the silver nitrate solution for a second preset time to obtain a tin-silver dendrite nanostructure, deposit the preset probe molecules on the surface of the tin-silver dendrite nanostructure, and prepare by two steps of displacement reaction and one step of deposition The tin-silver dendrite nanostructure is obtained, and by depositing probe molecules on the surface of the tin-silver dendrite nanostructure, under the incident condition of excitation light, since the tin-silver dendrite nanostructure has different scattering spectra for different probe molecules, The tin-silver dendrite nanostructure probe can enhance the Raman spectrum by increasing the scattering intensity of the probe molecule, that is, by increasing the intensity of the scattering peak.

Description

Preparation method of twice-reduced tin-silver dendritic nanostructures with enhanced Raman spectroscopy

technical field

The present application relates to the field of preparation of dendrite nanostructures, in particular, to a method for preparing Raman-enhanced Raman spectrum-reduced tin-silver dendrite nanostructures.

Background technique

Since the discovery of the surface-enhanced Raman scattering effect (SERS) in 1970, the non-contact non-destructive Raman spectroscopy detection technology capable of detecting single molecular limit analytes has shown strong vitality and has received extensive attention in many fields. Since the frequency shift of the Raman spectrum only depends on the vibrational energy level of the target molecule and has nothing to do with the excitation wavelength, the Raman spectrum can be used as the fingerprint spectrum of the molecule, and the target identification is very strong. Therefore, in practical engineering applications, Raman Spectroscopy has received more and more attention. Due to the small molecular Raman scattering cross-section, usually in the range of 10 ^-30 -10 ^-25 cm2, the Raman signal of free state molecules is extremely weak, and the spectral behavior of the detector is extremely demanding on the test environment, which greatly limits its engineering promotion.

In order to further enhance the Raman scattering spectrum signal, the researchers adsorbed the measured molecules on the surface of the noble metal nanostructure, and observed that the Raman spectrum intensity was enhanced. In the dendritic metal nanostructure, strong local field coupling occurs between two adjacent dendrites, which is easy to form electromagnetic hotspots, which can effectively enhance the electronic radiation transition rate of molecules and realize Raman spectrum enhancement. Therefore, it is particularly important to prepare metal dendritic nanostructure substrates with low cost and high stability.

However, the general preparation process of metal dendrite nanostructures in the prior art is relatively complicated, and the cost is high, so it is difficult to be applied to enhanced Raman scattering spectroscopy.

Contents of the invention

The object of the present invention is, aim at the above-mentioned deficiencies in the prior art, provide a kind of preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum, to solve the general problem of metal dendrite nanostructure in the prior art The preparation process is relatively complicated, the cost is high, and it is difficult to apply to the problem of enhancing Raman scattering spectroscopy.

In order to achieve the above object, the technical solution adopted in the embodiment of the present invention is as follows:

In the first aspect, the present application provides a method for preparing a Raman-enhanced secondary reduction tin-silver dendrite nanostructure, the method comprising:

placing the preset substrate in a stannous chloride-ethanol solution to react for the first preset time to obtain a tin dendrite nanostructure;

Under light-shielding conditions, placing the tin dendrite nanostructure in a silver nitrate solution for a second preset time to obtain the tin silver dendrite nanostructure;

Preset probe molecules are deposited on the surface of tin-silver dendrite nanostructures.

Optionally, the first preset time is 1 minute-5 minutes, and the second preset time is 30 minutes-180 minutes.

Optionally, before placing the preset substrate in the tin protochloride-ethanol solution to react for the first preset time, the step of obtaining the tin dendrite nanostructure also includes:

Dissolving SnCl ₂ ·2H ₂ O crystals in ethanol to obtain stannous chloride-ethanol solution;

Grinding, polishing and cleaning the surface of the preset substrate using the preset method.

Optionally, the amount of the SnCl ₂ ·2H ₂ O crystal is 0.034g, the amount of ethanol is 30ml, and the concentration of the stannous chloride-ethanol solution is 0.5×10 ^-2 mol/L.

Optionally, before the step of obtaining the tin-silver dendrite nanostructure by placing the tin dendrite nanostructure in the silver nitrate solution and reacting for a second preset time under light-shielding conditions:

Use nitrogen to dry the tin dendrite nanostructure;

Put silver nitrate crystal solution in deionized water to get silver nitrate solution.

Optionally, the amount of this deionized water is 100ml, the amount of silver nitrate crystals is 0.17g, and the concentration of silver nitrate solution is 0.01mol/L.

Optionally, the probe molecule is crystal violet.

The beneficial effects of the present invention are:

The preparation method of the Raman-enhanced secondary reduction tin-silver dendrite nanostructure provided by this application is to place the preset substrate in a stannous chloride-ethanol solution and react for the first preset time to obtain a tin dendrite nanostructure , under light-shielding conditions, place the tin dendrite nanostructure in silver nitrate solution to react for a second preset time to obtain the tin silver dendrite nanostructure, and deposit the preset probe molecules on the surface of the tin silver dendrite nanostructure , the present application has prepared a tin-silver dendrite nanostructure through two steps of displacement reaction and one step of deposition, and by depositing probe molecules on the surface of the tin-silver dendrite nanostructure, under the incident condition of excitation light, Since the tin-silver dendrite nanostructure has different scattering spectra for different probe molecules, the tin-silver dendrite nanostructure realizes Raman detection by increasing the light radiation efficiency of the probe molecule, that is, by increasing the intensity of the scattering peak. Enhancement of the spectrum.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention, and thus It should be regarded as a limitation on the scope, and those skilled in the art can also obtain other related drawings based on these drawings without creative work.

Fig. 1 is a schematic flow chart of a method for preparing a Raman-enhanced secondary reduction tin-silver dendrite nanostructure provided by an embodiment of the present invention;

2 is a schematic flow diagram of another method for preparing Raman-enhanced Raman spectrum secondary reduction tin-silver dendrite nanostructure provided by an embodiment of the present invention;

3 is a schematic flow diagram of another method for preparing a Raman-enhanced Raman spectrum secondary reduction tin-silver dendrite nanostructure provided by an embodiment of the present invention;

Fig. 4 is a structure diagram prepared by a method for preparing Raman-enhanced Raman spectrum-enhanced tin-silver dendrite nanostructures according to an embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is an embodiment of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the figures herein may be arranged and designed in a variety of different configurations. Note that similar numbers and letters denote similar items in the following figures, therefore, once an item is defined in one figure, it does not require further definition and explanation in subsequent figures.

In addition, the terms "first", "second", "third", etc. are only used for distinguishing descriptions, and should not be construed as indicating or implying relative importance.

In order to make the implementation process of the present invention clearer, the following will be described in detail in conjunction with the accompanying drawings.

Fig. 1 is a schematic flow diagram of a method for preparing a secondary reduction tin-silver dendrite nanostructure for enhanced Raman spectroscopy provided by an embodiment of the present invention; as shown in Fig. A method for preparing a sub-reduced tin-silver dendrite nanostructure, the method comprising:

S101. Place the preset substrate in a tin protochloride-ethanol solution to react for a first preset time to obtain a tin dendrite nanostructure.

The preset substrate is used to carry the structure prepared in this application. The material of the preset substrate can be aluminum or other metal materials, which are not specifically limited here. For the convenience of description, the preset substrate is used here The material of the bottom is metal aluminum for illustration. The preset substrate made of metal aluminum is generally shaped as aluminum foil. The size of the preset substrate is determined according to actual needs, and is not specifically limited here. In the pre-prepared stannous chloride-ethanol solution, the preset substrate is reacted in the stannous chloride-ethanol solution, because there are very much chloride ions and tin ions in the stannous chloride-ethanol solution, Because tin protochloride is only soluble in organic solvent, insoluble in water, then the application dissolves this tin protochloride in ethanol solution, has formed tin protochloride-ethanol solution, and in this stannous chloride-ethanol solution The tin ions can react the aluminum atoms in the predetermined substrate of the aluminum material, so that the replaced tin atoms are attached to the surface of the predetermined substrate of the aluminum material, and form branches on the surface of the predetermined substrate of the aluminum material. The crystal nanostructure, that is, the tin grows on the surface of the preset substrate of the aluminum material in the shape of dendrites.

Explanation of nouns, dendrites or dendrites are crystals that develop in the form of a typical multi-branched tree. Dendrite growth is very common and is illustrated by the formation of snowflakes and frost patterns on windows, the dendrites form a natural fractal pattern.

S102. Under the condition of avoiding light, place the tin dendrite nanostructure in the silver nitrate solution and react for a second preset time to obtain the tin silver dendrite nanostructure.

A tin dendrite nanostructure formed by a dendrite structure of tin atoms is formed on the surface of the preset substrate, and the tin dendrite nanostructure is placed in a silver nitrate solution, so that the tin atoms in the tin dendrite nanostructure React with this silver nitrate solution, because silver ion and nitrate ion exist in this silver nitrate solution, because this silver ion can replace the tin atom in this tin dendrite nanostructure, then under the effect of silver ion, this tin Part of the tin atoms on the surface of the dendrite nanostructure are replaced by silver ions, so that part of the tin atoms of the tin dendrite nanostructure are replaced by silver atoms, that is, the surface of the preset substrate forms a tin-silver dendrite nanostructure, that is, Two metals, tin and silver, form tin-silver dendrite nanostructures on the surface of the preset substrate; it should be noted that the shape, size, shape and other geometric data of the dendrites prepared in this application are related to the time of preparation, and here Not specifically limited.

S103. Deposit preset probe molecules on the surface of the tin-silver dendrite nanostructure.

Under the condition of incident excitation light, because the tin-silver dendrite nanostructure has different scattering spectra for different probe molecules, the Raman spectrum is enhanced. The preset probe molecules are deposited on the surface of the tin-silver dendrite nanostructure by a deposition method, that is, the surface layer of the tin-silver dendrite nanostructure on the surface of the preset substrate is provided with a structural layer formed by probe molecules.

Optionally, the first preset time is 1 minute-5 minutes, and the second preset time is 30 minutes-180 minutes.

Fig. 2 is a schematic flow chart of another method for preparing a Raman-enhanced secondary reduction tin-silver dendrite nanostructure provided by an embodiment of the present invention; as shown in Fig. 2, optionally, the preset substrate is placed Reacting for the first preset time in the stannous chloride-ethanol solution, the step of obtaining the tin dendrite nanostructure also includes:

S201. Dissolving SnCl ₂ ·2H ₂ O crystals in ethanol to obtain a stannous chloride-ethanol solution.

Since the _SnCl2.2H2O crystal can be dissolved in the organic solution, then the _SnCl2.2H2O crystal is mixed with the ethanol solution to obtain the stannous chloride-ethanol solution, the concentration and amount of the stannous chloride-ethanol solution It depends on actual needs, and no specific limitation is made here.

S202, using a preset method to polish and clean the surface of the preset substrate.

In order to facilitate the reaction between the preset substrate and the tin ions, before the reaction, the surface of the preset substrate is polished and polished, and the specific steps of the grinding and polishing are determined according to actual needs, and are not specifically limited here. Generally, finer sandpaper can be used for grinding, and deionized water can be used for cleaning after grinding, so that the surface of the preset substrate can be kept smooth and clean.

Optionally, the amount of the SnCl ₂ ·2H ₂ O crystal is 0.034g, the amount of ethanol is 30ml, and the concentration of the stannous chloride-ethanol solution is 0.5×10 ^-2 mol/L.

The SnCl ₂ 2H ₂ O crystal of 0.034g is used as a solvent, and the ethanol of 30ml is used as a solution, and the ratio of the SnCl ₂ 2H ₂ O crystal to the ethanol is based on the required tin protochloride-ethanol solution. It depends on the quantity, so I won’t go into details here.

Fig. 3 is a schematic flow chart of another method for preparing a Raman-enhanced secondary reduction tin-silver dendrite nanostructure provided by an embodiment of the present invention; as shown in Fig. 3, optionally, the , placing the tin dendrite nanostructure in the silver nitrate solution to react for a second preset time, the step of obtaining the tin silver dendrite nanostructure also includes:

S301, using nitrogen to dry the tin dendrite nanostructure;

Since the physical and chemical properties of nitrogen are stable and will not react with other ions in this application, nitrogen is used to dry up the liquid on the tin dendrites for subsequent reactions.

S302. Put the silver nitrate crystal solution in deionized water to obtain a silver nitrate solution.

Use the silver nitrate crystal of 0.17g, put into the deionized water of 100ml, obtain the silver nitrate solution of 0.01mol/L, be about to use the silver nitrate crystal of 0.17g as a solvent, with the deionized water of 100ml as a solution, the The ratio of silver nitrate crystals to the deionized water depends on the amount of silver nitrate solution required, and will not be repeated here.

Optionally, the amount of this deionized water is 100ml, the amount of silver nitrate crystals is 0.17g, and the concentration of silver nitrate solution is 0.01mol/L.

Optionally, the probe molecule is any one of rhodamine and crystal violet.

The probe molecule can be rhodamine or crystal violet, which is not specifically limited here.

Fig. 4 is the structural diagram of the structure prepared by the preparation method of the secondary reduction tin-silver dendrite nanostructure of a kind of enhanced Raman spectrum that one embodiment of the present invention provides; The preparation method of the sub-reduced tin-silver dendrite nanostructure, because only the above steps are used, realizes the simple preparation of the tin-silver dendrite nanostructure, and because the formation of the dendrite is formed according to the diffusion-limited aggregation and directional attachment mechanism , compared to other preparation methods, the preparation method of the present application has high stability, and according to experiments, the tin-silver dendrite nanostructure prepared by the preparation method of the present application has strong stability and high Raman activity; in Fig. 4 (a) It can be observed that at the beginning of the reaction, the displaced silver atoms are deposited on the Sn dendrites, showing that clusters of silver nanoparticles are adsorbed on the surface of the Sn dendrites to form a composite structure. Compared with the Sn dendrites, the Ag particles are smaller , the particle size is about 200nm. With the prolongation of the reaction time, the formed silver nanostructures accumulate gradually, and dendrites and fractal nanostructures are formed on the surface of Sn dendrites. As shown in Figure 4(b), the generated Ag nanoparticles accumulated on the surface of tin dendrites, and the particle size became smaller by about 130 nm. When the reaction time was increased to 90min, the Ag particles on the surface of the tin dendrites aggregated to form a dendrite structure, forming a Sn-Ag layered dendrite structure. It can be observed that there is a dendrite structure composed of Ag particles aggregated to form a backbone and fine side branches. The size is about 5–8 μm, and the side branches are 2 μm, as shown in Fig. 4(c). As the reaction time increased, Ag nanoparticles accumulated on the surface of Ag dendrites, forming a complex structure with multiple nanogaps, as shown in Figure 4(d). During the reaction process, the concentration of Ag+ decreased continuously, and the size of the Ag nanoparticles formed by replacement became smaller than before, with a diameter of 60 nm, and they were attached to the surface of the formed dendrite nanostructure, as shown in Figure 4(e). In Figure 4(f), it can be observed that as the reaction time increases, the branch size becomes larger, around 10 μm, and a symmetrically distributed multilayer nanostructure is formed, and side branch breakage occurs at the same time. During the reaction process, Ag atoms gradually accumulate and accumulate on the surface of Sn dendrites. Moreover, the present application can control the shape, size and shape of dendrites by controlling the reaction time, so the actual operation is convenient, and the preparation technology of the present application is simple and practical. In practical applications, this step needs to be performed under dark conditions.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. a kind of preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum, it is characterized in that, described method comprises: placing the preset substrate in a stannous chloride-ethanol solution to react for the first preset time to obtain a tin dendrite nanostructure; Under light-shielding conditions, placing the tin dendrite nanostructure in a silver nitrate solution for a second preset time to obtain a tin silver dendrite nanostructure; Depositing preset probe molecules on the surface of the tin-silver dendrite nanostructure; Wherein, the first preset time is 2 minutes, and the second preset time is 120 minutes, and the silver nanoparticles accumulate on the surface of the silver dendrites to form a complex structure with multiple nano-gaps. 2. the preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum according to claim 1, is characterized in that, described preset substrate is placed in tin protochloride-ethanol solution and reacts the first For a predetermined time, before the step of obtaining the tin dendrite nanostructure, it also includes: Dissolving SnCl ₂ ·2H ₂ O crystals in ethanol to obtain stannous chloride-ethanol solution; Grinding and polishing and cleaning the surface of the predetermined substrate by using a predetermined method. 3. the preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum according to claim 2, is characterized in that, described SnCl ₂ .2H ₂ The amount of O crystal is 0.034g, and the amount of ethanol The volume is 30ml, and the concentration of the stannous chloride-ethanol solution is 0.5×10 ^-2 mol/L. 4. the preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum according to claim 3, is characterized in that, described under light-shielding condition, described tin dendrite nanostructure is placed in nitric acid Reacting in the silver solution for a second preset time, before the step of obtaining the tin-silver dendrite nanostructure, also includes: The tin dendrite nanostructure is blown dry using nitrogen gas; Put silver nitrate crystal solution in deionized water to get silver nitrate solution. 5. the preparation method of the secondary reduction tin-silver dendrite nanostructure of enhanced Raman spectrum according to claim 4, is characterized in that, the amount of described deionized water is 100ml, and the amount of described silver nitrate crystal is 0.17 g, the concentration of the silver nitrate solution is 0.01mol/L. 6. The method for preparing Raman-enhanced secondary reduction tin-silver dendrite nanostructure according to any one of claims 1-5, wherein the probe molecule is crystal violet.

Images