A Pt x Te y :Ag 2 Te quantum dots, synthesis methods and applications thereof

Abstract

The present invention relates to the technical field of quantum dots in the near-infrared region, and specifically relates to a Pt x Te y :Ag2Te quantum dot, its synthesis method and application. The quantum dot has a multi-layer structure, with Ag2Te quantum dots inside and a Pt x Te y outer layer structure, where x is any integer from 1 to 3 and y is any integer from 1 to 4. Compared with traditional silver telluride quantum dots, it has a longer fluorescence emission wavelength, up to 2200 nm, and improves the upper limit of the wavelength regulation range compared with existing technical methods. It is an NIR-II silver-based quantum dot, with the characteristics of low toxicity, silver-based, and near-infrared region quantum dots. The synthesis method of the present invention is to continuously grow Pt x Te y on the surface of Ag2Te quantum dots to obtain Pt x Te y :Ag2Te quantum dots with different particle sizes and different fluorescence emission wavelengths.

Description

Technical Field

[0001] The present invention relates to the technical field of near-infrared quantum dots, and in particular to a Pt x Te y :Ag 2 Te quantum dots, their synthesis methods and applications. Background Art

[0002] Quantum dots are a type of fluorescent marker that began to develop at the end of the last century. They have unique fluorescent properties compared to traditional fluorescent dyes. Quantum dots have the advantages of good photostability and high fluorescence intensity. Quantum dots whose fluorescence emission is located in the second near-infrared window (NIR-II) are more suitable for in vivo imaging because of their stronger tissue penetration and higher signal-to-noise ratio. In the early stages of near-infrared quantum dot research, most materials contained toxic and heavy metal elements such as Pb and Cd. The potential toxicity problems caused by toxic elements greatly limited the application of quantum dots in biological imaging and other aspects; in addition, the environmental pollution problems caused by toxic elements cannot be ignored. Therefore, the preparation of low-toxic NIR-II quantum dots is an important direction for the development of fluorescent semiconductor materials. Ag with a narrow bulk band gap 2 X (X = S, Se or Te) is an excellent choice for the preparation of NIR-II QDs.

[0003] New low-toxic "Cd-free", "Pb-free", low-toxic Ag 2 Se, Ag 2 Te quantum dots as fluorescent probes have been increasingly studied, and metal-doped near-infrared quantum dots have also been continuously developed in recent years, but their fluorescence emission wavelength and quantum yield have not been well regulated.

[0004] Therefore, further improving the fluorescence properties of NIR-II quantum dots through metal doping and growth regulation is an important research direction for relevant researchers. Summary of the invention

[0005] One of the purposes of the present invention is to provide a Pt x Te y :Ag 2 Te quantum dots are low-toxic, silver-based, near-infrared quantum dots.

[0006] The second object of the present invention is to provide a Pt x Te y :Ag 2 The synthesis method of Te quantum dots is simple to operate and easy to control.

[0007] The third object of the present invention is to provide a Pt x Te y :Ag 2Applications of Te quantum dots.

[0008] The solution adopted by the present invention to achieve one of the purposes is: a Pt x Te y :Ag 2 Te quantum dots, characterized in that: the quantum dots have a multi-layer structure, the interior of which is Ag 2 Te quantum dots, the outer layer is Pt x Te y , where x is any integer from 1 to 3, and y is any integer from 1 to 4.

[0009] Preferably, the values ​​of x and y are at least one of the following combinations: x=1, y=2; x=2, y=3; x=3, y=4; x=1, y=2.

[0010] Preferably, the Pt x Te y Mainly includes PtTe 2 , Pt 2 Te 3 , Pt 3 Te 4 , PtTe.

[0011] The solution adopted by the present invention to achieve the second purpose is: a Pt x Te y :Ag 2 The synthesis method of Te quantum dots is based on the conventional Ag 2 Platinum ions are added to the synthesis of Te quantum dots to make Ag 2 Pt continues to grow on the surface of Te quantum dots x Te y Formation of Pt x Te y :Ag 2 Te quantum dots.

[0012] Preferably, the specific synthesis steps are: continuously introducing a protective gas into an octadecene solvent, then adding a silver source, a thiol ligand and a platinum source and heating to 120-140° C. to obtain a mixed solution; injecting a Te precursor into the mixed solution and keeping the temperature constant to react to obtain a near-infrared hydrophobic Pt x Te y :Ag 2 Te quantum dots.

[0013] Preferably, the Te precursor is TBP-Te or TOP-Te, and the preparation method of the Te precursor comprises: dissolving tellurium powder in tributylphosphine or tri-n-octylphosphine at room temperature under a protective atmosphere, mixing evenly to obtain a colorless transparent solution, and obtaining a Te precursor.

[0014] Preferably, the silver source is silver acetate, the platinum source is platinum tetrachloride, and the thiol ligands are octanethiol and n-dodecyl mercaptan.

[0015] Preferably, the molar ratio of the silver source, the platinum source, the Te precursor and the mercapto ligand is 10:(2-30):2.5:(700-730).

[0016] Preferably, when Pt x Te y PtTe 2 When the molar ratio of the silver source to the platinum source is 10:(2-4); when Pt x Te y Pt 2 Te 3 When the molar ratio of the silver source to the platinum source is 10:(5-10) x Te y Pt 3 Te 4 When the molar ratio of the silver source to the platinum source is 10:(11-22); when Pt x Te y When it is PtTe, the molar ratio of the silver source to the platinum source is 10:(23-30).

[0017] The present invention is in conventional Ag 2 Based on the synthesis of Te quantum dots, platinum was added to develop a new Pt x Te y :Ag 2 Te quantum dot material, the emission wavelength can be adjusted in the range of 1480-2200nm. The surface of the material has a heterogeneous structure. As the amount of platinum added increases, the outer layer structure of the material can be PtTe 2 , Pt 2 Te 3 , Pt 3 Te 4 , PtTe, Pt with different structures x Te y :Ag 2 Te quantum dots have different morphologies, lattice structures and particle lengths. As the length of the material increases, its corresponding band gap gradually becomes smaller, which is also the fundamental reason for the regulation of the fluorescence emission wavelength.

[0018] The solution adopted by the present invention to achieve the third purpose is: a Pt x Te y :Ag 2 The use of Te quantum dots in low-toxic, silver-based, near-infrared quantum dot contrast agents.

[0019] The present invention has the following advantages and beneficial effects:

[0020] The Pt of the present invention x Te y :Ag 2 Compared with traditional silver telluride quantum dots, Te quantum dots have a longer fluorescence emission wavelength, which can reach 2200nm, and compared with the existing technical methods, the upper limit of the control wavelength range is increased. It is a NIR-II silver quantum dot, which has the characteristics of low toxicity, silver, and near-infrared quantum dots.

[0021] The synthesis method of the present invention uses Ag 2 Te quantum dots induce Pt x Te y The growth can realize the regulation of the fluorescence emission wavelength; at the same time, the present invention provides a new wavelength regulation method for NIR-II silver quantum dots, by 2 Pt continues to grow on the surface of Te quantum dots x Te y Obtain Pt with different particle sizes and different fluorescence emission wavelengths x Te y :Ag 2 Te quantum dots.

[0022] The Pt of the present invention x Te y :Ag 2 Te quantum dots can be used in low-toxic, silver-based, near-infrared quantum dot contrast agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The emission spectra of quantum dots with different fluorescence emission wavelengths obtained in Examples 1-4 of the present invention;

[0024] Figure 2 From left to right are the different wavelengths Pt obtained in the embodiments of the present invention. x Te y :Ag 2 TEM images, particle size (based on length) statistics and EDX element spectrum of Te quantum dots;

[0025] Figure 3 The different wavelengths of Pt obtained in Examples 1-4 of the present invention x Te y :Ag 2 Calculated band gap diagram of Te quantum dots;

[0026] Figure 4 Pt prepared in Example 2 of the present invention 2 Te 3 :Ag 2Spherical aberration-corrected transmission electron microscopy image of Te quantum dots;

[0027] Figure 5 The Pt with a fluorescence emission wavelength of 1730 nm after hydrophilic modification in Example 5 of the present invention 2 Te 3 :Ag 2 UV spectrum and fluorescence emission spectrum of Te quantum dots;

[0028] Figure 6 The hydrophilic Pt having a fluorescence emission wavelength of 1730 nm in Example 5 of the present invention 2 Te 3 :Ag 2 In vivo fluorescence imaging of Te-OIPA quantum dots;

[0029] Figure 7 is Pt in Example 6 of the present invention 2 Te 3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 Diagram of the photothermal heating effect of Te quantum dots. DETAILED DESCRIPTION

[0030] The present invention will be described in detail below in conjunction with specific implementations and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific implementations and examples are used to illustrate the present invention, rather than to limit the present invention.

[0031] Throughout the specification, unless otherwise specifically stated, the terms used herein should be understood as meanings commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. In the event of a conflict, the present specification takes precedence.

[0032] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or obtained by existing methods. Steps S1, S2, S3, etc. of the present invention do not represent a strict order relationship, and the order can be adjusted appropriately as needed.

[0033] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0034] According to a typical embodiment of the present invention, there is provided a Pt x Te y :Ag 2 A method for preparing Te quantum dots, the method comprising:

[0035] Step S1, continuously introducing protective gas into octadecene solvent, then adding silver acetate, octyl mercaptan and platinum tetrachloride and heating to 120-140° C. to obtain a mixed solution; injecting TBP-Te precursor into the mixed solution and keeping the temperature unchanged to continue the reaction to obtain near-infrared hydrophobic Pt x Te y :Ag 2 Te quantum dots.

[0036] In the step S1, the preparation method of the TBP-Te precursor includes: dissolving tellurium powder in tributylphosphine in a glove box at room temperature, mixing well and then ultrasonicating for 10 to 20 minutes to obtain a colorless transparent solution, thereby obtaining the TBP-Te precursor.

[0037] The molar ratio of the silver acetate to the platinum tetrachloride is 10:(2-30).

[0038] The molar ratio of the silver acetate to the platinum tetrachloride is 10:(2-4), and PtTe is obtained. 2 :Ag 2 Te quantum dots.

[0039] The molar ratio of the silver acetate to the platinum tetrachloride is 10:(5-10), and Pt 2 Te 3 :Ag 2 Te quantum dots.

[0040] The molar ratio of the silver acetate to the platinum tetrachloride is 10:(11-22), and Pt 3 Te 4 :Ag 2 Te quantum dots.

[0041] The molar ratio of the silver acetate to the platinum tetrachloride is 10:(23-30), and PtTe:Ag 2 Te quantum dots.

[0042] According to a typical embodiment of the present invention, there is provided a method of converting Pt x Te y :Ag 2 A method for modifying Te quantum dots to be hydrophilic, the method comprising:

[0043] Step S2: firstly prepare the hydrophobic Pt x Te y :Ag 2 Te quantum dots are treated to be hydrophilic before further application.

[0044] Specifically, the hydrophilic operation is: hydrophobic Pt x Te y :Ag2 Te quantum dots and oleylamine-grafted polyacrylic acid (OIPA) were dissolved in chloroform solvent, and the white powder was completely dissolved by ultrasonication. The resulting solution was dried by rotary evaporator to remove chloroform. The product was dispersed by adding Brton-Robinson (BR) buffer, and then centrifuged to remove the precipitate. The excess OIPA empty micelles were separated by density gradient centrifugation to obtain the product.

[0045] The hydrophobic Pt x Te y :Ag 2 The mass ratio of Te quantum dots to the OIPA is 1:(2-3);

[0046] The concentration of the Brton-Robinson (BR) buffer is 0.03-0.06 M, pH=12;

[0047] The centrifugal speed for removing the precipitate by centrifugation in step S2 is 6000-10000 rpm, and the centrifugal time is 10-20 min;

[0048] The centrifugal speed of the density gradient centrifugation in step S2 is 40000-60000 rpm, and the centrifugation time is 4-6 hours.

[0049] The following will describe in detail a low-toxic, silver-based, near-infrared quantum dot and its preparation method of the present application in combination with embodiments, comparative examples and experimental data.

[0050] Example 1, PtTe 2 :Ag 2 Te quantum dots and preparation method thereof

[0051] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well, and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.0674 g (0.2 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution; 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain a near-infrared hydrophobic PtTe with a fluorescence emission wavelength of 1650 nm. 2 :Ag 2 Te quantum dots.

[0052] Example 2, Pt 2 Te 3 :Ag 2 Te quantum dots and preparation method thereof

[0053] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.135 g (0.4 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution; 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain a near-infrared hydrophobic Pt with a fluorescence emission wavelength of 1730 nm. 2 Te 3 :Ag 2 Te quantum dots.

[0054] Example 3, Pt 3 Te 4 :Ag 2 Te quantum dots and preparation method thereof

[0055] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well, and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.337 g (1 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution;

[0056] 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain near-infrared hydrophobic Pt 3 Te 4 :Ag 2 Te quantum dots.

[0057] Example 4, PtTe:Ag 2 Te quantum dots and preparation method thereof

[0058] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well, and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.674 g (2 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution;

[0059] 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain near-infrared hydrophobic PtTe:Ag with a fluorescence emission wavelength of 2200 nm.2 Te quantum dots.

[0060] Example 5: Pt 2 Te 3 :Ag 2 Fluorescence Imaging Application of Te Quantum Dots

[0061] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.135 g (0.4 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution; 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain a near-infrared hydrophobic Pt with a fluorescence emission wavelength of 1730 nm. 2 Te 3 :Ag 2 Te quantum dots.

[0062] To obtain hydrophilic Pt 2 Te 3 :Ag 2 Te, hydrophobic Pt purified using acetone 2 Te 3 :Ag 2 Te quantum dots, purified hydrophobic Pt 2 Te 3 :Ag 2 Te QDs (20 mg) and oleylamine-grafted OIPA (50 mg) were dissolved in chloroform (50 ml) and ultrasonicated for 30 min. The white powder gradually dissolved and the mixture gradually turned into a clear brown solution. The chloroform was then dried by rotary evaporation. 20 ml of Brton-Robinson (BR) buffer (0.05 M, pH 12) was added to redisperse the product. The precipitate was removed by centrifugation at 7000 rpm for 15 min, and the excess OIPA micelles were separated by rapid density gradient centrifugation. The hydrophilic Pt 2 Te 3 :Ag 2 Te-OIPA quantum dots were washed 5 times with PBS buffer and then dispersed in PBS buffer. 2 Te 3 :Ag 2 The ultraviolet spectrum and fluorescence emission spectrum of Te quantum dots are shown in Figure 5 shown.

[0063] BALB / c-nu mice (6 weeks) were anesthetized with isoflurane and 0.2 ml (10 mg / ml) of Pt 2 Te 3 :Ag 2 Te-OIPA quantum dots. Imaged using the NIR-II small animal imaging system, using an 808nm laser, with a laser power density of ≈100mW / cm 2 , exposure time 500ms, imaging picture Figure 6 shown.

[0064] Example 6, Pt 2 Te 3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 Photothermal heating effect of Te quantum dots

[0065] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.135 g (0.4 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution; 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain a near-infrared hydrophobic Pt with a fluorescence emission wavelength of 1730 nm. 2 Te 3 :Ag 2 Te quantum dots.

[0066] In a glove box, 0.128 g (1 mmol) of tellurium powder was dissolved in 10 ml of tributylphosphine, mixed well and then ultrasonicated for 15 minutes to obtain a colorless transparent solution to obtain a TBP-Te precursor; argon was continuously introduced into 15 ml of octadecene solvent, and then 0.337 g (1 mmol) of platinum tetrachloride, 0.067 g (0.4 mmol) of silver acetate, and 5 ml of octanethiol were added and heated to 130° C. to obtain a mixed solution; 1 ml (0.1 mmol) of TBP-Te precursor was injected into the mixed solution and the temperature was kept constant for 30 minutes to obtain a near-infrared hydrophobic Pt with a fluorescence emission wavelength of 1970 nm. 3 Te 4 :Ag 2 Te quantum dots.

[0067] The obtained hydrophobic quantum dots were purified with acetone and dispersed in a tetrachloroethylene solution. 2 Te3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 Te quantum dots and Ag without platinum addition 2 Te quantum dots were placed in a cell culture dish. A power density of 20 mW / cm 2 The solution was irradiated with an 808nm laser and the solution temperature was measured every 30 seconds. The heating effect is shown in the attached figure. Figure 7 As shown, the addition of platinum is greater than the original Ag 2 Te quantum dot materials have faster and higher heating capabilities.

[0068] like Figure 1 The emission spectra of quantum dots with different fluorescence emission wavelengths obtained in the embodiments of the present invention are shown. Figure 1 It can be seen that PtTe 2 :Ag 2 The fluorescence emission wavelength of Te quantum dots is 1650nm. Through high-resolution lattice analysis, the outer crystal plane spacing of the material is similar to that of PtTe 2 Consistent Pt 2 Te 3 :Ag 2 The fluorescence emission wavelength of Te quantum dots is 1730nm. Through high-resolution lattice analysis, the spacing between the outer crystal planes of the material and Pt 2 Te 3 Consistent; Pt 3 Te 4 :Ag 2 The fluorescence emission wavelength of Te quantum dots is 1970nm. The high-resolution lattice analysis shows that the spacing between the outer crystal planes of the material is similar to that of Pt 3 Te 4 Consistent; PtTe:Ag 2 The fluorescence emission wavelength of Te quantum dots is 2200nm. Through high-resolution lattice analysis, it is found that the outer crystal plane spacing of the material is consistent with PtTe; Ag without platinum tetrachloride doping 2 The fluorescence emission wavelength of Te quantum dots is 1550nm.

[0069] like Figure 2 The different wavelengths of Pt obtained in the embodiment of the present invention are shown. x Te y :Ag 2 TEM, particle size (based on length) statistics and EDX element spectrum of Te quantum dots. Figure 2 It can be seen that PtTe 2 :Ag 2 The average particle size of Te quantum dots is 4.25 nm, and that of Pt 2 Te3 :Ag 2 The average particle size of Te quantum dots is 5.09 nm, and that of Pt 3 Te 4 :Ag 2 The average particle size of Te quantum dots is 7.10 nm, PtTe:Ag 2 The average particle size of Te quantum dots is 8.06nm. The content of platinum increases with the increase of quantum dot length.

[0070] like Figure 3 The different wavelengths of Pt obtained in the embodiment of the present invention are shown. x Te y :Ag 2 Bandgap calculation diagram of Te quantum dots, calculated based on solid UV diffuse reflectance data, PtTe with a fluorescence emission wavelength of 1650nm 2 :Ag 2 The band gap of Te quantum dots is 1.98 eV, and the fluorescence emission wavelength is 1730 nm. 2 Te 3 :Ag 2 The band gap of Te quantum dots is 1.75 eV, and the fluorescence emission wavelength is 1970 nm. 3 Te 4 :Ag 2 The band gap of Te quantum dots is 1.29 eV, and the fluorescence emission wavelength is 2200 nm. 2 The band gap of Te quantum dots is 1.08 eV.

[0071] like Figure 4 The Pt prepared in Example 2 of the present invention is shown. 2 Te 3 :Ag 2 Spherical aberration corrected transmission electron microscopy of Te quantum dots. The distribution of Ag, Te, and Pt elements can be seen from the figure. The inner layer is mainly composed of Ag and Te elements, and the outer layer is mainly composed of Pt and Te elements.

[0072] like Figure 5 The Pt after hydrophilic modification in Example 5 is shown. 2 Te 3 :Ag 2 The ultraviolet spectrum and fluorescence emission spectrum of Te quantum dots show that after being solubilized in water, the quantum dots have a wide range of ultraviolet absorption and a fluorescence emission wavelength of 1710nm.

[0073] like Figure 6The figure shows the imaging effect of mice in Example 5. The quantum dots with fluorescence emission wavelength in the second near-infrared region have lower fluorescence background interference and deeper penetration depth, and the tiny blood vessels on the back and abdomen of the mice are clearly visible.

[0074] like Figure 7 The Pt in Example 6 is shown 2 Te 3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 Photothermal heating effect of Te quantum dots, in Ag 2 Te、Pt 2 Te 3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 Under the premise of maintaining the same concentration of Te quantum dots and irradiating with the same laser conditions and time, Ag 2 Te、Pt 2 Te 3 :Ag 2 Te and Pt 3 Te 4 :Ag 2 The temperature change value of Te quantum dots gradually increases.

[0075] The above is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principle of the present invention, and these improvements and changes are also regarded as the protection scope of the present invention.

Claims

1. A Pt x Te y :Ag 2 Te quantum dots, Features: The quantum dots have a multi-layer structure, with Ag inside. 2 Te quantum dots, the outer layer structure is Pt x Te y , where x is any integer from 1 to 3, and y is any integer from 1 to 4.

2. Pt according to claim 1 x Te y :Ag 2 Te quantum dots, Features: The values ​​of x and y are at least one of the following combinations: x=1, y=2; x=2, y=3; x=3, y=4.

3. Pt according to claim 1 x Te y :Ag 2 Te quantum dots, Features: The Pt x Te y Including PtTe 2 , Pt 2 Te 3 , Pt 3 Te 4 , PtTe.

4. A Pt according to any one of claims 1 to 3 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: In conventional Ag 2 Platinum ions are added to the synthesis of Te quantum dots to make Ag 2 Pt continues to grow on the surface of Te quantum dots x Te y Formation of Pt x Te y :Ag 2 Te quantum dots.

5. Pt according to claim 4 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: The specific synthesis steps are: continuously introducing protective gas into octadecene solvent, then adding silver source, thiol ligand and platinum source and heating to 120-140°C to obtain a mixed solution; injecting Te precursor into the mixed solution and keeping the temperature unchanged to react to obtain near-infrared hydrophobic Pt x Te y :Ag 2 Te quantum dots.

6. Pt according to claim 5 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: The Te precursor is TBP-Te or TOP-Te. The preparation method of the Te precursor comprises: dissolving tellurium powder in tributylphosphine or tri-n-octylphosphine at room temperature under a protective atmosphere, mixing evenly to obtain a colorless transparent solution, and obtaining the Te precursor.

7. Pt according to claim 5 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: The silver source is silver acetate, the platinum source is platinum tetrachloride, and the thiol ligands are octanethiol and n-dodecyl mercaptan.

8. Pt according to claim 7 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: The molar ratio of the silver source, the platinum source, the Te precursor and the mercapto ligand is 10: (2-30): 2.5: (700-730).

9. Pt according to claim 8 x Te y :Ag 2 Synthesis method of Te quantum dots, Features: When Pt x Te y PtTe 2 When the molar ratio of the silver source to the platinum source is 10:(2-4); when Pt x Te y Pt 2 Te 3 When the molar ratio of the silver source to the platinum source is 10: (5-10) x Te y Pt 3 Te 4 When the molar ratio of the silver source to the platinum source is 10:(11-22); when Pt x Te y When it is PtTe, the molar ratio of the silver source to the platinum source is 10:(23-30).

10. Pt according to any one of claims 1 to 3 x Te y :Ag 2 Use of Te quantum dots or quantum dots synthesized by the synthesis method described in any one of claims 4 to 9 in low-toxic, silver-based, near-infrared quantum dot contrast agents.

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