WO2019148707A1

WO2019148707A1 - Synthesis and optical manipulation method for multi-branched tree-shaped composite nanostructure of plasmonic waveguide

Info

Publication number: WO2019148707A1
Application number: PCT/CN2018/088741
Authority: WO
Inventors: 张晓阳; 张彤; 秦妍妍; 薛小枚
Original assignee: 东南大学
Priority date: 2018-01-30
Filing date: 2018-05-28
Publication date: 2019-08-08
Also published as: CN108303765B; CN108303765A

Abstract

The present invention comprises a synthesis and optical manipulation method for a multi-branched tree-shaped composite nanostructure of a plasmonic waveguide. The synthesis method comprises multiple steps, and all of the steps can be precisely controlled. Both the thickness of a trunk of the tree-shaped nanostructure and the thickness of a branch-shaped nanostructure grown thereon can be precisely controlled. A composite tree-shaped nanostructure employing quantum dots is formed by superimposing shelled or shell-less quantum dots on a surface of the tree-shaped nanostructure, wherein the shell-free quantum dots can be applied to chemical catalysis, environmental monitoring, and biosensing. Light enters at one end of a nanowire, passes through the nanowire and the tree-shaped structure, and excites the shelled quantum dots to emit light. The present invention can be applied to remote sensing Raman and novel lasers. Optical manipulation changes the intensity and a polarization status of incident light, controls quantum dots in a specific region to emit light, and eliminates a crosstalk effect caused by interference and diffraction effects among scattering centers, thereby allowing application to sub-wavelength high-resolution detection.

Description

Composite nanostructure synthesis and optical manipulation method of multi-branched plasmon waveguide

Technical field

The invention relates to the field of nano materials and the field of chemical biology, in particular to a method for synthesizing and optically controlling a multi-branched plasmon waveguide composite nanostructure.

Background technique

The plasmon waveguide is a sub-wavelength-scale waveguide that can confine photons to the vicinity of the waveguide surface, thereby breaking the diffraction limit and manipulating photons at sub-wavelengths and even nanoscales, thus in biochemical detection, data storage, and chips. Interconnections, solar cells and many other aspects have broad application prospects and have received extensive research attention. Silver nanowires are plasmon waveguides that have been extensively studied for their large-scale synthesis by chemical methods, non-toxic and harmless. However, since the wave vector of the surface plasmon is larger than the light wave vector at the same frequency, the silver nanowire cannot be directly excited by the plane wave in air or vacuum, and only one mode of excitation at one end is used. Due to the smooth surface of the silver nanowires, most of the light is exponentially attenuated on the side of the silver nanowires during the propagation of light from the excitation end to the other end of the nanowires, which cannot be effectively scattered into the off-line space and cannot be fully utilized. The earth limits the range of applications of silver nanowires, and new complex nanostructures that can transmit and significantly scatter plasmon signals are urgently needed.

Remote sensing excitation is an effective means to enhance the detection effect, and has important application prospects in the fields of environmental monitoring, biological detection, and chemical biosensing. In order to enhance the scattering effect, some people try to bind the quantum dots to the silver nanowires, but the quantum dots of the existing quantum dot composite nanostructures are randomly scattered on the surface of the nanowires, which makes the quantum dots only distributed on the side of the nanowires. Light can only be transmitted through the quantum dot scattering to the local space close to the nanowire, which greatly limits the transmission path and transmission range of the light, making it difficult to realize the practical application of the nanostructure in remote sensing excitation. Therefore, it is necessary to propose a new structure having a large number of scattering centers and capable of transmitting light over a plurality of paths over long distances.

Optical manipulation techniques based on surface plasmons have attracted widespread attention in recent years due to their low laser energy requirements and simple devices. The lower laser energy density prevents damage to living cells, and therefore can be applied to living cells and DNA manipulation in the medical field. The existing micro/nano optical structures are densely arranged in the scattering center, and when the distance between adjacent scattering centers is relatively close, interference and diffraction are easily generated between the scattered waves, causing crosstalk. In the course of cancer treatment, if this micro-nano optical component is injected into the human body, the scattered light will not only destroy the cancer cells, but also may damage the surrounding healthy tissue. Nano-optical structures that accurately destroy cancer cells at specific locations without damaging human healthy tissue are urgently needed.

Summary of the invention

Technical Problem: The object of the present invention is to overcome the deficiencies of the prior art, and to provide a method for synthesizing and optically controlling a multi-branched plasmon waveguide composite nanostructure, which is simple and reproducible. Good, easy to industrialize mass production; the stem and branch nanostructures of the prepared tree-shaped nanostructures are controllable, and the dendritic nanostructures increase the number of scattering centers and extend the space through which light can propagate; in the tree-shaped nanostructures The surface is superimposed with shell or shellless quantum dots to form quantum dot composite tree-shaped nanostructures. The shellless quantum dots can be used in chemical catalysis, environmental monitoring, biosensing, etc., and light is incident from one end of the nanowire, through nanowires and branches. The structure is transmitted to the shell quantum dots to excite the chiral quantum dots to emit light, which can be used for remote sensing Raman, new lasers and other applications. The optical control can change the intensity and polarization state of the incident light, control the quantum dot luminescence of a specific region, and eliminate the crosstalk effect caused by the interference diffraction effect between the scattering centers.

Technical Solution: The method for synthesizing and optically controlling a multi-branched tree-shaped plasmon waveguide composite nanostructure of the present invention comprises the following steps:

Step 1: Synthesis of dendritic nanostructures:

a. Chemical reduction method to synthesize coarse and fine controllable silver nanowires as the backbone of dendritic nanostructures: prepare a mixed solution of silver nitrate, polyvinylpyrrolidone PVP and sodium chloride, and the concentration of silver nitrate in the reaction system is 0.001-5mmol / L, and fully reacted at high temperature for 1-8h, to obtain silver nanowire solution I;

b. Cleaning and processing the silver nanowire to form a defect on the surface thereof: the silver nanowire solution I is thoroughly washed 2-3 times, and then the surface treatment agent A is added, thoroughly mixed and stirred, and the originally smooth silver nanowire surface is treated with a treatment agent. Forming one or more defects after cleaning to obtain a silver nanowire solution II, which is a trunk of a tree-shaped nanostructure;

c. growing a thickness-controlled dendritic nanostructure at a surface defect of the silver nanowire to form a tree-shaped nanostructure: preparing a mixed aqueous solution of silver nitrate, PVP, weak reducing agent B and photocatalyst C, thoroughly mixing and stirring, and then mixing Rapidly add strong reducing agent D in the solution, and immediately use a single-wavelength narrow-line wide blue light source to illuminate, blue light induces the formation of high-yield silver decahedron, and continues to stir in the dark, to obtain the precursor solution III of the branch;

d. The precursor solution III and the silver nanowire solution II of the branch are thoroughly mixed and placed under a white light source for continuous illumination. Under the illumination condition, the surface activity of the silver seed crystal is increased, interconnected and continued at the surface defects of the nanowire. Growing to form a silver nano-dendritic structure to obtain a dendritic nanostructure solution;

Step 2: Synthesis of quantum dot composite tree nanostructures:

b. Shellless quantum dot synthesis: a mixed solution of chromium oxide, stearic acid and octadecene ODE is heated to 170-230 ° C, and the solution is cooled to room temperature, and octadecyl ODA and tri-n-octylphosphine oxide TOPO are added. The mixed solution is heated to 250-330 ° C under argon protection. At this temperature, sulfur, selenium or tellurium is dissolved in TBP, and the concentration of sulfur, selenium or tellurium in the reaction system is 0.001- 10mmol / L; followed by dilution with ODE to obtain a mixed solution IV, the mixed solution IV was quickly injected into the reaction system, and the reaction mixture solution was cooled to room temperature to obtain a shell-free quantum dot solution;

b. Core-shell-coated quantum dot synthesis: the eutectic solution of nanocrystal E is thoroughly mixed with ODA and ODE, and the reaction system is evacuated to remove hexane and residual air from the system, followed by argon gas at high temperature. The cadmium solution is injected underneath, and after 5-10 minutes, the sulfur is injected into the ODE solution, and after fully reacting, it is cooled to room temperature to obtain a cadmium sulfide-coated quantum dot solution;

c. Removing the tree-shaped nanostructure surface capping agent to make it easy to superimpose quantum dots on the surface: the tree-shaped nanostructure solution is centrifuged 1-2 times at high speed to remove the capping agent on the surface of the branch, and the concentration is 0.001-10 mmol/L. Solution V; the shellless and core-shell-encapsulated quantum dot solution is centrifuged 2-3 times at high speed, and configured into an aqueous solution VI having a concentration of 0.001-10 mmol/L;

d. Quantum dot modification and phase inversion to make it easy to superimpose on the surface of the tree-shaped nanostructure: dissolve the dithiol bond molecule in water, prepare a solution with a concentration of 0.001-10mmol/L, mix it with solution VI and fully Stirring ensures that the thiol bond at one end of the dithiol bond molecule is completely adsorbed on the surface of the quantum dot, the other end of the thiol bond is exposed in deionized water, and the centrifuged quantum dot is dissolved in the organic solvent F to obtain a concentration of 0.001-10 mmol. /L mixed solution VII; the amphiphilic molecule of the ethanol solution is dropped into the solution VII until the flocculation is formed, the flocculent precipitate is extracted by high-speed centrifugation, and dissolved in deionized water to obtain a solution VIII;

e. Forming a quantum dot composite tree-shaped nano-heterostructure: mixing solution V and solution VIII, stirring for 1-2 h, ensuring that the bare thiol bond in the solution and the tree-shaped nanostructure in solution V are fully adsorbed, and finally the synthesis is randomly combined. The dendritic tree-shaped nanostructures and the novel nanocomposite heterostructures formed by the quantum dots bound on the surface thereof, thereby achieving luminescence enhancement or quenching, and electrical Schottky contact or ohmic contact, produce a thermoelectron effect.

among them:

The backbone of the tree-shaped nanostructures is a diameter-controlled silver nanowire straight waveguide, a two-dimensional, quasi-two-dimensional or three-dimensional metal waveguide structure, and the material of the synthetic nanowire is also replaced by an alloy or a polymer material.

The surface treatment agent A is acetone, toluene, cyclopentanone, dimethylformamide DMF, hydrogen peroxide, hydrochloric acid or nitric acid, wherein the concentration of the surface treatment agent in the reaction system is 0.001 to 10 mmol/L.

The weak reducing agent B is sodium citrate, glucose or vitamin C, the photocatalyst C is L-arginine, and the strong reducing agent D is sodium borohydride, potassium borohydride or lithium aluminum hydride, wherein sodium citrate, PVP The volume ratio of L-arginine, silver nitrate and sodium borohydride is 60-100:1-5:6-15:2-6:20-50, and the branch diameter is controllable from 10 nm to 400 nm.

The nanocrystal E used in the synthesis of the core-shell-encapsulated quantum dots is cadmium sulfide, cadmium telluride or cadmium selenide.

The organic solvent F is n-hexane, chloroform or toluene.

The amphiphilic molecule is mercaptopropionic acid MPA, cetyltrimethylammonium bromide CTAB, PVP or tetrafluoroboric acid nitrate NOBF ₄ .

The quantum dots bound to the tree-shaped nanostructures can also be replaced with dopamine or azathioprine.

The optical manipulation method of the multi-branched plasmon waveguide composite nanostructure synthesized by the synthetic method of the invention, the method is lighted at one end of the trunk of the tree-shaped nanostructure, and the light is transmitted through the nanowire to the dendritic nanostructure, dendritic The nanostructures are split, and the shell-shaped quantum dots superimposed by light are excited to emit light; the brightness of the incident quantum light is controlled to control the brightness of the shell quantum dots, and the polarization state of the incident light is controlled to selectively control different regions. The shelled quantum dots emit light.

Silver nanowires have a surface plasmon effect that excites electromagnetic waves that travel along the metal and air interface. However, since the wave vector of the surface plasmon is larger than the light wave vector at the same frequency, the silver nanowire with smooth surface cannot be directly excited by the plane wave in air or vacuum, and only one mode of excitation at one end is used. In the process of light propagating from the excitation end of the nanowire to the other end, most of the light is exponentially attenuated on the side of the silver nanowire and cannot be fully utilized.

Surface-enhanced Raman scattering (SERS) spectroscopy is a highly sensitive technique that provides information on the chemical structure of the sample to be tested, and has broad application prospects in biochemical imaging and remote sensing. The SERS enhancement effect is closely related to the type, size and shape of the metal forming the substrate nanostructure. The enhancement of the excitation and scattering electromagnetic fields formed by the surface plasmon resonance can greatly enhance the SERS effect. The edges and raised points of the anisotropic nanoparticles are regions with strong electromagnetic fields, and the position with the strongest scattering enhancement is called the scattering center, that is, the "hot spot", which is in the nanogap between the nanoparticles. By coupling different types of nanoparticles into the system, a better spatial distribution of SERS "hot spots" can be formed, which in turn provides better detection of uniformity and repeatability.

Dendritic silver nanostructures have special optical properties due to their unique morphology and structure. The sharp edges and multi-stage branches make the dendritic silver nanostructures have excellent SERS effect and can be used to prepare SERS active substrates with high sensitivity and high reproducibility. The growth of dendritic structures on the surface of silver nanowires can disperse light, greatly increasing the number of light transmission paths, extending the space through which light can travel, allowing light to travel farther, and improving the excitation light for the trunk. Utilization; at the same time, the large surface area of the dendritic structure can greatly increase the contact between the analyte and the detection substrate, and enhance the effect of Raman detection.

Advantageous Effects: The present invention has the following advantages over the prior art:

1. The multi-branched tree-shaped plasmon waveguide composite nanostructure prepared by the invention has not been proposed before, and has originality. The thickness of the nanowire trunk and the dendritic nanostructure can be precisely controlled. The dendritic nanostructure greatly increases the number of scattering centers of the nanostructure, which greatly enhances the Raman scattering, which can be used for remote sensing excitation. When the trunk and dendritic nanostructures are coarse, the loss generated by the plasmon waveguide in the process of transmitting light is low; when the trunk and dendritic nanostructures are fine, the plasmon waveguide has a better local effect on light. The size of the nanowire trunk and the dendritic nanostructures, the length of the branches, and the area of the dendritic network are controlled by controlling the proportion of the reagents and the illumination time to obtain a tree-shaped plasmon that can achieve the desired shape. Waveguide structure. When the area of the dendritic network is large, more scattered scattering centers can be provided, thereby extending the space for light propagation and improving the utilization of incident light.

2. The multi-branched plasmon waveguide composite nanostructure prepared by the invention realizes different properties of materials, and between zero-dimensional quantum dots, one-dimensional nanowires and two-dimensional dendritic nanostructures among different dimensions of nanostructures Composite. The superposition of quantum dots on the surface of the branches can greatly increase the number of scattering centers, and can realize remote sensing excitation, which fully improves the utilization of light. Binding of quantum dots on the surface of dendritic nanostructures can achieve catalytic oxidation and catalytic degradation, and can be used as SERS probes in environmental monitoring, biological detection, chemical biosensing and other fields. When used for luminescence, the core-shell encapsulation can solve the fluorescence quenching problem caused by quantum dot exposure. The quantum-doped quantum dots are bound to the quantum-coated nano-structures on the surface of the tree-shaped nanostructures, and the light is from the end of the tree trunk. The excitation is transmitted to the branches through the trunk, and then propagated to the quantum dots by the branches, which stimulates the quantum dots to emit light, forming a novel nano-light source, which can also be used for nano-illumination. The light intensity can be provided by the optical signals excited by the trunk, opening up a new application direction.

3. The present invention has for the first time developed a multi-dimensional multi-branched tree-shaped plasmon waveguide composite nanostructure, which can be effectively regulated by a new optical manipulation method. The quantum dot luminescence at different positions of the tree-shaped nanostructure can be excited by tuning the polarization state and intensity of the incident light, which can eliminate the crosstalk effect caused by the interference diffraction effect between the scattering centers, and can be used for high-resolution detection of sub-wavelength. The use of such nanostructures for cancer treatment can accurately destroy cancer cells at specific locations without causing damage to human healthy tissues, and can be applied to living cells and DNA manipulation in the medical field. At the same time, the active composite nanostructure can also form a novel light emitter. This multi-branched plasmon waveguide composite nanostructure is expected to be widely used in nanophotonic materials, chemical biosensing, environmental monitoring, biological detection and medical fields.

4. The chemical reagents used in the method of the invention are non-toxic and harmless, the heating temperature is low, and the experiment period is short; the equipment used in the invention has simple process and convenient operation process. Therefore, it is a simple, flexible and low-energy synthesis method, which can be widely used from the perspective of green chemistry.

DRAWINGS

1 is a schematic view of a multi-branched tree-shaped nanocomposite structure and an optical path. In the figure, 1 is the trunk of the nanowire, 2 is the dendritic structure growing on the trunk, 31 is the quantum dot wrapped by the core shell, 32 is the exposed quantum dot, and 33 is the quantum dot of the luminescent core envelope. The light is excited from the end of the "nano-tree" trunk, propagates through the trunk to the dendritic structure, and then propagates to the quantum dots by the dendritic structure, stimulating the quantum dots of the core-shell to emit light, and the quantum dots of the region passing through the light do not emit light.

Figure 2 is a schematic diagram of optical manipulation. When the polarization states of the incident light are different, the quantum dots corresponding to the different regions emit light, and the inside of the dotted line frame is the light-emitting region.

Figure 3 is an optical microscope image of an experimentally prepared dendritic nanocomposite structure.

4 is a partial schematic diagram and corresponding resonance spectrum of optical manipulation of a quantum dot composite tree nano-heterostructure. Wherein, A represents a quantum-shell-enclosed quantum dot grown on the left waveguide branch, B represents a core-shell-enclosed quantum dot grown on the right-side waveguide branch, D represents a spatial distance between quantum dots A and B, and X represents no When performing optical regulation, the photoresponse of quantum dots A and B, Y represents the photoresponse of quantum dots A and B when the polarization angle of incident light is θ ₁ , and Z represents the quantum dot A when the polarization angle of incident light is θ ₂ And the light response produced by B.

Detailed ways

The invention is further illustrated by the following specific examples and comparative examples:

Example:

1. Prepare 0.1 M silver nitrate, 0.2 M sodium chloride, 0.6 M PVP ethylene glycol solution, and mix the solution at 160 ° C for 2 h.

2. Take 10 ml of the mixed solution, add 0.5 ml of acetone, and stir well.

3. Add 5 ml of sodium citrate (0.5 M), 0.5 ml L-arginine (0.05 M), 0.15 ml PVP (0.5 M), 0.2 ml silver nitrate (0.5 M) in 7 ml of deionized water. After the solution was stirred well, 2 ml of sodium borohydride (0.4 M) was slowly added dropwise, and the solution was further stirred for 20 min in the dark.

4. 7 ml of the solution prepared in step 3 was mixed into the solution prepared in step 1, and the mixed solution was irradiated under a white LED for 2 h to obtain a dendritic nanostructure solution.

5. A mixed solution of 0.2 mmol of chromium oxide, 0.8 mmol of stearic acid and 2 g of ODE was heated to 200 ° C, and the solution was cooled to room temperature, 1.5 g of ODA and 0.5 g of TOPO were added, and the reaction system was heated to 280 ° C. At this temperature, 2 mmol of sulfur was dissolved in TBP, followed by diluting the solution with 1.37 g of ODE, and the mixed solution was quickly injected into the reaction system. The reaction mixture solution was cooled to room temperature to obtain a shell-free quantum dot solution.

6. 2.44 g of cadmium sulfide in hexane was thoroughly mixed with 1.5 g of ODA and 5 g of ODE, and the reaction system was first evacuated at a temperature of 100 ° C for 30 min. Next, argon gas was introduced into the reaction system, and the reaction solution was heated to 240 °C. 0.49 ml of cadmium solution was injected, and after 8 min of reaction, a sulfur ODE solution (0.04 M) was injected, and after fully reacting, it was cooled to room temperature to obtain a cadmium sulfide-coated quantum dot solution.

7. The silver nano-branches solution was centrifuged 1-2 times at high speed to remove the capping agent on the surface of the branches, and was set to a solution having a concentration of 5 mmol/L. The quantum dot solution wrapped in the shell or core shell was centrifuged twice at a high speed to remove the capping agent on the surface, and was set to a solution having a concentration of 4 mmol/L.

8. Dissolve the dithiol bond molecule in deionized water, dispose it as a solution with a concentration of 5 mmol/L, mix it with the quantum dot solution, stir well for 2 h, centrifuge at high speed for 3 times, and then arrange to a concentration of 4 mmol/L. Toluene solution. The ethanol solution of MPA was dropped into the solution until a floc was formed, and the flocculent precipitate was extracted by centrifugation and dissolved in deionized water.

9. The treated branch solution and the quantum dot solution were mixed and stirred for 1 h to obtain a quantum dot composite tree-shaped nanostructure.

10. Fig. 4 is a partial schematic diagram of a quantum dot composite tree nano-heterostructure and a corresponding resonance spectrum. The spacing D between quantum dots A and B is 10 nm. As indicated by the reference X, when optical control is not performed, the quantum dots A and B emit light at the same time, since the spacing between A and B is extremely small, and interference occurs at the same time when light is emitted, thereby causing a crosstalk effect. The symbols Y and Z show the light response of A and B when the polarization state of the incident light is changed by optical manipulation. The incident light intensity of Y and Z is the same, and there is a slight difference between the polarization angles θ ₁ and θ ₂ . By adjusting the polarization state of the incident light, quantum dots A and B can be controlled to emit light separately, thereby eliminating crosstalk-induced crosstalk benefits.

In addition, those skilled in the art can make other changes within the spirit of the invention, and it is to be understood that these changes are intended to be included within the scope of the invention.

Claims

A method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure, characterized in that the method comprises the following steps:

Step 1: Synthesis of dendritic nanostructures:

a. Chemical reduction method to synthesize coarse and fine controllable silver nanowires as the backbone of dendritic nanostructures: prepare a mixed solution of silver nitrate, polyvinylpyrrolidone PVP and sodium chloride, and the concentration of silver nitrate in the reaction system is 0.001-5mmol / L, and fully reacted at high temperature for 1-8h, to obtain silver nanowire solution I;

b. Cleaning and processing the silver nanowire to form a defect on the surface thereof: the silver nanowire solution I is thoroughly washed 2-3 times, and then the surface treatment agent A is added, thoroughly mixed and stirred, and the originally smooth silver nanowire surface is treated with a treatment agent. Forming one or more defects after cleaning to obtain a silver nanowire solution II, which is a trunk of a tree-shaped nanostructure;

c. growing a thickness-controlled dendritic nanostructure at a surface defect of the silver nanowire to form a tree-shaped nanostructure: preparing a mixed aqueous solution of silver nitrate, PVP, weak reducing agent B and photocatalyst C, thoroughly mixing and stirring, and then mixing Rapidly add strong reducing agent D in the solution, and immediately use a single-wavelength narrow-line wide blue light source to illuminate, blue light induces the formation of high-yield silver decahedron, and continues to stir in the dark, to obtain the precursor solution III of the branch;

d. The precursor solution III and the silver nanowire solution II of the branch are thoroughly mixed and placed under a white light source for continuous illumination. Under the illumination condition, the surface activity of the silver seed crystal is increased, interconnected and continued at the surface defects of the nanowire. Growing to form a silver nano-dendritic structure to obtain a dendritic nanostructure solution;

Step 2: Synthesis of quantum dot composite tree nanostructures:

a. Shellless quantum dot synthesis: a mixed solution of chromium oxide, stearic acid and octadecene ODE is heated to 170-230 ° C, the solution is cooled to room temperature, and octadecyl ODA and tri-n-octylphosphine oxide TOPO are added. The mixed solution is heated to 250-330 ° C under argon protection. At this temperature, sulfur, selenium or tellurium is dissolved in TBP, and the concentration of sulfur, selenium or tellurium in the reaction system is 0.001- 10mmol / L; followed by dilution with ODE to obtain a mixed solution IV, the mixed solution IV was quickly injected into the reaction system, and the reaction mixture solution was cooled to room temperature to obtain a shell-free quantum dot solution;

b. Core-shell-coated quantum dot synthesis: the eutectic solution of nanocrystal E is thoroughly mixed with ODA and ODE, and the reaction system is evacuated to remove hexane and residual air from the system, followed by argon gas at high temperature. The cadmium solution is injected underneath, and after 5-10 minutes, the sulfur is injected into the ODE solution, and after fully reacting, it is cooled to room temperature to obtain a cadmium sulfide-coated quantum dot solution;

c. Removing the tree-shaped nanostructure surface capping agent to make it easy to superimpose quantum dots on the surface: the tree-shaped nanostructure solution is centrifuged 1-2 times at high speed to remove the capping agent on the surface of the branch, and the concentration is 0.001-10 mmol/L. Solution V; the shellless and core-shell-encapsulated quantum dot solution is centrifuged 2-3 times at high speed, and configured into an aqueous solution VI having a concentration of 0.001-10 mmol/L;

d. Quantum dot modification and phase inversion to make it easy to superimpose on the surface of the tree-shaped nanostructure: dissolve the dithiol bond molecule in water, prepare a solution with a concentration of 0.001-10mmol/L, mix it with solution VI and fully Stirring ensures that the thiol bond at one end of the dithiol bond molecule is completely adsorbed on the surface of the quantum dot, the other end of the thiol bond is exposed in deionized water, and the centrifuged quantum dot is dissolved in the organic solvent F to obtain a concentration of 0.001-10 mmol. /L mixed solution VII; the amphiphilic molecule of the ethanol solution is dropped into the solution VII until the flocculation is formed, the flocculent precipitate is extracted by high-speed centrifugation, and dissolved in deionized water to obtain a solution VIII;

e. Forming a quantum dot composite tree-shaped nano-heterostructure: mixing solution V and solution VIII, stirring for 1-2 h, ensuring that the bare thiol bond in the solution and the tree-shaped nanostructure in solution V are fully adsorbed, and finally the synthesis is randomly combined. The dendritic tree-shaped nanostructures and the novel nanocomposite heterostructures formed by the quantum dots bound on the surface thereof, thereby achieving luminescence enhancement or quenching, and electrical Schottky contact or ohmic contact, produce a thermoelectron effect.
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the trunk of the tree-shaped nanostructure is a diameter-controlled silver nanowire straight waveguide, two-dimensional, quasi-scale Two-dimensional or three-dimensional various metal waveguide structures, materials for synthesizing nanowires are also replaced by alloy or polymer materials.
The method for synthesizing a multi-branched plasmon waveguide composite nanostructure according to claim 1, wherein the surface treatment agent A is acetone, toluene, cyclopentanone or dimethylformamide. DMF, hydrogen peroxide, hydrochloric acid or nitric acid, wherein the concentration of the surface treatment agent in the reaction system is 0.001 to 10 mmol/L.
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the weak reducing agent B is sodium citrate, glucose or vitamin C, and the photocatalyst C is L-arginine, strong reducing agent D is sodium borohydride, potassium borohydride or lithium aluminum hydride, wherein the volume ratio of sodium citrate, PVP, L-arginine, silver nitrate, sodium borohydride is 60-100: 1-5:6-15:2-6:20-50, the diameter of the branches is controllable from 10 nm to 400 nm.
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the nanocrystal E used for the synthesis of the core-shell-encapsulated quantum dots is cadmium sulfide or cadmium telluride or Cadmium selenide.
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the organic solvent F is n-hexane, chloroform or toluene.
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the amphiphilic molecule is mercaptopropionic acid MPA or cetyltrimethyl bromide. Ammonium CTAB, PVP or tetrafluoroboric acid nitrate NOBF 4 .
The method for synthesizing a multi-branched tree-shaped plasmon waveguide composite nanostructure according to claim 1, wherein the quantum dots bound to the tree-shaped nanostructures can also be replaced with dopamine or azole. Hey.
An optical manipulation method for a multi-branched plasmon waveguide composite nanostructure synthesized by the synthesis method according to claim 1, wherein the method passes light at one end of the trunk of the tree-shaped nanostructure, and the light passes through the nanometer The wire is conducted to the dendritic nanostructure, the dendritic nanostructure is split, and the shelled quantum dots superimposed by the light are excited to emit light; the light intensity of the incident light is controlled to realize the regulation of the brightness of the shell quantum dot by controlling the incident light. The polarization state enables selective control of chimeric quantum dot luminescence in different regions.