1. Preparation of AgInS₂A method of quantum dots, comprising:

mixing an Ag source, an In source, a surface ligand and a first solvent to obtain a cation precursor solution; mixing an S source with a second solvent to obtain an anion precursor solution;

after the cation precursor solution is subjected to first heating treatment, injecting the anion precursor solution into the cation precursor solution, and performing first synthesis reaction to obtain AgInS₂A quantum dot stock solution;

for the AgInS₂Centrifuging the quantum dot stock solution, and cleaning the obtained clear solution to obtain the AgInS₂And (4) quantum dots.

2. The method according to claim 1, wherein the Ag source is selected from at least one of silver acetate, silver carbonate, silver nitrate, sulfate, silver halide;

optionally, the In source is selected from at least one of indium acetate, indium nitrate, indium sulfate, indium halide, and indium acetylacetonate;

optionally, the surface ligand is dodecyl mercaptan;

optionally, the S source is selected from at least one of thiourea, N-dimethylthiourea and elemental sulfur;

optionally, the first solvent is selected from at least one of oleylamine, octadecylamine, octadecene;

optionally, the second solvent is selected from at least one of ethanol, methanol, n-propanol, isopropanol.

3. The method of claim 1, wherein the molar ratio of the Ag source, the In source, the surface ligand, and the first solvent is 1 (0.5-3): 2-8): 60-70;

optionally, according to Ag in the cation precursor solution⁺Molar ratio to said S sourceThe method comprises the following steps of (1), (2-10), injecting the anion precursor solution into the cation precursor solution;

optionally, injecting the anion precursor solution into the cation precursor solution at a rate of 1-20 mL/h, preferably, injecting the anion precursor solution into the cation precursor solution at a rate of 1-20 mL/h in a continuous dripping manner.

4. The method according to claim 1, wherein the second solvent is preheated to 50 to 70 ℃ in advance.

5. The method according to claim 1, wherein the first heat treatment is performed at a temperature of 120 to 130 ℃ for 30 to 60 min;

optionally, the temperature adopted by the first synthesis reaction is 140-200 ℃ and the time is 10-90 min.

6. The method according to claim 1, wherein the rotation speed for the centrifugal treatment is 4000-8000 r/min for 3-10 min.

7. Preparation of AgInS₂/GaS_xA method of quantum dots, comprising:

providing AgInS₂Quantum dots;

mixing a Ga source, an S source and a third solvent to obtain a solution of a precursor of the cladding reagent;

after the second heating treatment is carried out on the solution of the precursor of the cladding reagent, the AgInS is injected into the solution of the precursor of the cladding reagent₂Quantum dots and carrying out a second synthesis reaction to obtain AgInS₂/GaS_xA quantum dot stock solution;

for the AgInS₂/GaS_xCleaning the quantum dot stock solution to obtain the AgInS₂/GaS_xAnd (4) quantum dots.

8. According to claim 7The method of (1), wherein the AgInS₂The quantum dot is prepared by the method of any one of claims 1 to 6;

optionally, the Ga source is selected from at least one of gallium acetylacetonate, gallium chloride, gallium nitrate;

optionally, the third solvent is selected from at least one of oleylamine, octadecene.

9. The method according to claim 7, wherein the molar ratio of the Ga source, the S source and the third solvent is 1 (1-3) to (100-300);

optionally, according to said AgInS₂The molar ratio of the quantum dots to the Ga source is 1 (1-50), and AgInS is injected into the encapsidation reagent precursor solution₂And (4) quantum dots.

10. The method according to claim 7, wherein the temperature used for the second heat treatment is 120 to 130 ℃ for 30 to 60 min;

optionally, the temperature adopted by the second synthesis reaction is 200-300 ℃, the heating rate is 1-3 ℃/min, and the time is 5-60 min.

Background

Quantum Dots (QDs), also known as semiconductor nanocrystals, exhibit unique electronic and optical properties, such as broad excitation spectra, narrow emission spectra, tunable emission wavelengths with size components, good photostability, etc., which make them widely used in the fields of bio-imaging, light emitting diodes, solar cells and light emitting devices.

At present, binary quantum dots are mostly applied, the quantum dots are mostly composed of II-VI and IV-VI semiconductor elements, such as CdSe, CdTe, PbS and the like, and the potential toxicity of heavy metal elements such as Cd, Pb and the like contained in the quantum dots greatly limits the practical application of the quantum dots.

AgInS₂The quantum dots do not contain heavy metal elements, have the advantages of low toxicity and environmental protection, have a very large absorption coefficient in a visible light region, and are luminescent materials with great potential.

For AgInS₂The synthesis of quantum dots presents a general challenge to balance the reactivity of two cationic precursors with one anionic precursor, since Ag⁺And In³⁺The reactivity of the compound has great difference, the compound has different bond energy with S, and intrinsic defects are easy to generate. To balance the reactions of Ag, In and S sources, at 2007, researchers used a single precursor pyrolysis method to prepare AgInS₂Quantum dots, however, this method necessitates designing a molecular precursor for each composition, and it is difficult to control the particle size and shape due to the complexity of the decomposition process. Thus, the existing preparation of (I-III-VI) AgInS₂Methods of quantum dots remain to be improved.

Disclosure of Invention

The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. To this end, it is an object of the present invention to propose a process for preparing (I-III-VI) AgInS₂A method of quantum dots. The method can prepare the narrow-band side-emitting AgInS₂The quantum dot and the method have high controllability and can meet the requirements of practical application.

In one aspect of the invention, the invention provides a method for preparing AgInS₂A method of quantum dots. According to an embodiment of the invention, the method comprises: mixing an Ag source, an In source, a surface ligand and a first solvent to obtain a cation precursor solution; mixing an S source with a second solvent to obtain an anion precursor solution; after the first heat treatment is carried out on the cation precursor solution, the anion is injected into the cation precursor solutionIon precursor solution is subjected to a first synthesis reaction to obtain AgInS₂A quantum dot stock solution; for the AgInS₂Centrifuging the quantum dot stock solution, and cleaning the obtained clear solution to obtain the AgInS₂And (4) quantum dots. Therefore, the method can prepare the narrow-band edge-emitting AgInS₂The quantum dot and the method have high controllability and can meet the requirements of practical application.

In addition, preparation of AgInS according to the above-described embodiments of the invention₂The method of quantum dots may also have the following additional technical features:

in some embodiments of the invention, the Ag source is selected from at least one of silver acetate, silver carbonate, silver nitrate, sulfate, silver halide.

In some embodiments of the present invention, the In source is selected from at least one of indium acetate, indium nitrate, indium sulfate, indium halide, indium acetylacetonate.

In some embodiments of the invention, the surface ligand is dodecyl mercaptan.

In some embodiments of the invention, the S source is selected from at least one of thiourea, N-dimethylthiourea, elemental sulfur.

In some embodiments of the invention, the first solvent is selected from at least one of oleylamine, octadecylamine, octadecene.

In some embodiments of the invention, the second solvent is selected from at least one of ethanol, methanol, n-propanol, isopropanol.

In some embodiments of the present invention, the molar ratio of the Ag source, the In source, the surface ligand and the first solvent is 1 (0.5-3): 2-8): 60-70.

In some embodiments of the invention, Ag is in the cationic precursor solution⁺And the molar ratio of the S source to the cation precursor solution is 1 (2-10), and the anion precursor solution is injected into the cation precursor solution.

In some embodiments of the present invention, the anionic precursor solution is injected into the cationic precursor solution by continuous dripping at a rate of 1-20 mL/h.

In some embodiments of the present invention, the anionic precursor solution is injected into the cationic precursor solution by continuous dripping at a rate of 1-20 mL/h.

In some embodiments of the present invention, the second solvent is preheated to 50 to 70 ℃ in advance.

In some embodiments of the present invention, the temperature used for the first heating treatment is 120-130 ℃ for 30-60 min.

In some embodiments of the present invention, the temperature used in the first synthesis reaction is 140-200 ℃ for 10-90 min.

In some embodiments of the present invention, the rotation speed for the centrifugal treatment is 4000 to 8000r/min, and the time is 3 to 10 min.

In another aspect of the invention, the invention provides a method for preparing AgInS₂/GaS_xA method of quantum dots. According to an embodiment of the invention, the method comprises: providing AgInS₂Quantum dots; mixing a Ga source, an S source and a third solvent to obtain a solution of a precursor of the cladding reagent; after the second heating treatment is carried out on the solution of the precursor of the cladding reagent, the AgInS is injected into the solution of the precursor of the cladding reagent₂Quantum dots and carrying out a second synthesis reaction to obtain AgInS₂/GaS_xA quantum dot stock solution; for the AgInS₂/GaS_xCleaning the quantum dot stock solution to obtain the AgInS₂/GaS_xAnd (4) quantum dots. Therefore, the method can prepare the narrow-band edge-emitting AgInS₂/GaS_xThe quantum dot and the method have high controllability and can meet the requirements of practical application.

In addition, preparation of AgInS according to the above-described embodiments of the invention₂/GaS_xThe method of quantum dots may also have the following additional technical features:

in some embodiments of the invention, the AgInS₂The quantum dots are prepared from AgInS of the above examples₂The quantum dots are prepared by a method.

In some embodiments of the invention, the Ga source is selected from at least one of gallium acetylacetonate, gallium chloride, gallium nitrate.

In some embodiments of the invention, the third solvent is selected from at least one of oleylamine, octadecene.

In some embodiments of the present invention, the molar ratio of the Ga source, the S source and the third solvent is 1 (1-3) to (100-300).

In some embodiments of the invention, the AgInS is as described₂The molar ratio of the quantum dots to the Ga source is 1 (1-50), and AgInS is injected into the encapsidation reagent precursor solution₂And (4) quantum dots.

In some embodiments of the present invention, the temperature used for the second heating treatment is 120-130 ℃ for 30-60 min.

In some embodiments of the present invention, the temperature used in the second synthesis reaction is 200-300 ℃, the heating rate is 1-3 ℃/min, and the time is 5-60 min.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 shows the mononuclear AgInS prepared in example 1₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectra of the quantum dots;

FIG. 2 shows the mononuclear AgInS prepared in example 2₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectra of the quantum dots;

FIG. 3 is a mononuclear AgInS prepared in example 3₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectra of quantum dots.

Detailed Description

The following describes embodiments of the present invention in detail. The following examples are illustrative only and are not to be construed as limiting the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In one aspect of the invention, the invention provides a method for preparing AgInS₂A method of quantum dots. The preparation of AgInS according to an embodiment of the invention is further described below₂The method of quantum dots is described in detail.

Firstly, according to the embodiment of the invention, an Ag source, an In source, a surface ligand and a first solvent are mixed to obtain a cation precursor solution; and mixing the S source with a second solvent to obtain an anion precursor solution.

The specific kinds of the Ag source, the In source, the surface ligand, the first solvent, the S source, and the second solvent are not particularly limited, and may be selected by those skilled In the art according to actual needs. According to some embodiments of the present invention, the Ag source may be selected from at least one of silver acetate, silver carbonate, silver nitrate, sulfate, silver halide. According to some embodiments of the present invention, the In source may be selected from at least one of indium acetate, indium nitrate, indium sulfate, indium halide, and indium acetylacetonate. According to some embodiments of the invention, the surface ligand may be dodecyl mercaptan. According to some embodiments of the invention, the S source may be selected from at least one of thiourea, N-dimethylthiourea, elemental sulfur. According to some embodiments of the present invention, the first solvent may be selected from at least one of oleylamine, octadecylamine, octadecene, preferably oleylamine. According to some embodiments of the present invention, the second solvent may be selected from at least one of ethanol, methanol, n-propanol, isopropanol, preferably ethanol.

According to some embodiments of the present invention, the second solvent is preheated to 50-70 ℃, such as 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃ and the like in advance. The inventors found that by preheating the second solvent to the above temperature, the solubility of the S source therein can be further improved, thereby further facilitating the progress of the quantum dot synthesis reaction. If the preheating temperature is too high, the solvent is quickly volatilized, the control of the reaction is not facilitated, and potential safety hazards are generated.

According to some embodiments of the present invention, the molar ratio of the Ag source, the In source, the surface ligand and the first solvent is 1 (0.5-3): 2-8): 60-70. Specifically, the molar ratio of the Ag source to the In source may be 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, etc., the molar ratio of the Ag source to the surface ligand may be 1:2, 1:3, 1:4, 1:5, 1:6, 1:8, etc., and the molar ratio of the Ag source to the first solvent may be 1:60, 1:65, 1:70, etc. The inventor finds that due to the great difference of the reactivity of the Ag source, the In source and the S source, the bond energies formed among Ag, In and S are different, and the AgInS is easy to be caused₂Quantum dots produce many defects. The Ag source and the In source are set In the above range, so that AgInS can be obtained₂The internal defects and surface dangling bonds of the nanocrystalline are minimized, so that the AgInS₂The nano-particles have good crystallization, the surface is well modified, the non-radiative transition is effectively reduced, and the AgInS is improved₂The luminescent properties of the quantum dots. On the other hand, the dosage of the surface ligand has obvious influence on the improvement of the fluorescence performance of the quantum dot, and the quantum dot can effectively prevent the aggregation of the nano-crystal, reduce the defects on the surface of the quantum dot and adjust the size of the quantum dot to a proper range, thereby improving the luminous intensity and the luminous peak of the quantum dot. More preferably, the surface proportion adopts dodecyl mercaptan, and the charging molar ratio of the Ag source to the dodecyl mercaptan is 1: 3. Dodecyl mercaptan and Ag⁺、In³⁺Has effective coordination function, and has better effect under the feeding molar ratio. On the other hand, if the amount of the first solvent is too small, AgInS is not favorable₂The nucleation and growth of the quantum dots finally influence the fluorescence performance of the product; if the first solvent is used in excessIn addition, the centrifugal washing of the product in the subsequent treatment is difficult, and the preparation cost is increased and unnecessary waste is caused. More preferably, the Ag source to first solvent feed molar ratio is 1: 50.

Further, according to an embodiment of the present invention, after the first heat treatment is performed on the cation precursor solution, the anion precursor solution is injected into the cation precursor solution, and the first synthesis reaction is performed, so as to obtain AgInS₂And (4) quantum dot stock solution. Preferably, this step is carried out in an inert gas atmosphere (e.g., argon, etc.). The water and oxygen in the cation precursor solution can be effectively removed by carrying out the first heating treatment, and then the AgInS can be obtained by injecting the anion precursor solution and carrying out the first synthesis reaction₂And (4) quantum dot stock solution.

According to some embodiments of the invention, Ag is in the cationic precursor solution⁺And (3) injecting an anion precursor solution into the cation precursor solution, wherein the molar ratio of the S source to the S source is 1 (2-10). In particular, Ag in the cation precursor solution⁺The molar ratio to the S source may be 1:2, 1:4, 1:5, 1:6, 1:8, 1:10, etc., and the anion precursor solution is injected into the cation precursor solution by continuous instillation. Therefore, the fluorescence performance of the quantum dot product can be further improved, and the size of the quantum dot product can be further adjusted to a proper range.

According to some embodiments of the present invention, the anion precursor solution is injected into the cation precursor solution at a rate of 1-20 mL/h. Specifically, the injection rate may be 1mL/h, 2mL/h, 4mL/h, 6mL/h, 8mL/h, 10mL/h, 12mL/h, 14mL/h, 16mL/h, 18mL/h, 20mL/h, or the like. Therefore, the fluorescence performance of the quantum dot product can be further improved, and the size of the quantum dot product can be further adjusted to a proper range. More preferably, the anionic precursor solution is injected in a continuous instillation manner, thereby making it easier to control the reaction rate and control the size of the quantum dot crystals.

The presence of water and oxygen is detrimental to the fluorescent properties of the quantum dots. By subjecting the cation precursor solution to the first heat treatment, water and oxygen therein can be effectively removed. According to some embodiments of the present invention, the temperature used for the first heat treatment may be 120 to 130 ℃ (e.g., 120 ℃, 125 ℃, 130 ℃, etc.), and the time may be 30 to 60min (e.g., 30min, 40min, 50min, 60min, etc.). Therefore, the removal effect of water and oxygen in the cation precursor solution is better.

According to some embodiments of the present invention, the temperature used in the first synthesis reaction may be 140 to 200 ℃ (e.g., 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃, 200 ℃, etc.), and the time may be 10 to 90min (e.g., 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min, etc.). The inventor finds that the crystal form of the quantum dot product can be further improved and the fluorescence performance of the quantum dot product can be improved by carrying out the first synthesis reaction under the conditions.

Further, according to an embodiment of the present invention, for AgInS₂Centrifuging the quantum dot stock solution, and cleaning the obtained clear solution to obtain AgInS₂And (4) quantum dots. Thus, impurities, large particles, and residual raw materials generated in the first synthesis reaction can be effectively removed. And cleaning the clear liquid obtained by centrifugal treatment to obtain the clean and high-quality AgInS₂And (4) quantum dots. Preferably, the supernatant is washed with ethanol several times (e.g., twice, three times, four times, etc.).

According to some embodiments of the present invention, the rotation speed for the centrifugation may be 4000 to 8000r/min (e.g., 4000r/min, 5000r/min, 6000r/min, 7000r/min, 8000r/min, etc.), and the time may be 3 to 10min (e.g., 3min, 5min, 7min, 9min, 10min, etc.). By subjecting AgInS to the above conditions₂The quantum dot stock solution is subjected to centrifugal treatment, wherein the removal effect of impurities and residual raw materials is better.

In another aspect of the invention, the invention provides a method for preparing AgInS₂/GaS_xA method of quantum dots. The preparation of AgInS according to an embodiment of the invention is further described below₂/GaS_xThe method of quantum dots is described in detail.

First, according to an embodiment of the present invention, AgInS is provided₂Quantum dots. According to some embodiments of the invention, AgInS₂The quantum dots are prepared from AgInS of the above examples₂The quantum dots are prepared by a method.

Further, according to an embodiment of the present invention, a Ga source, an S source and a third solvent are mixed to obtain a capping reagent precursor solution.

Specific kinds of the Ga source, the S source, and the third solvent are not particularly limited and may be selected by those skilled in the art according to actual needs. According to some embodiments of the invention, the Ga source may be selected from at least one of gallium acetylacetonate, gallium chloride, gallium nitrate, preferably gallium acetylacetonate. According to some embodiments of the invention, the S source may be selected from at least one of thiourea, N-dimethylthiourea, elemental sulfur. According to some embodiments of the invention, the third solvent is selected from at least one of oleylamine, octadecene, preferably oleylamine.

According to some embodiments of the present invention, the molar ratio of the Ga source, the S source and the third solvent is 1 (1-3) to (100-300). Specifically, the molar ratio of the Ga source to the S source may be 1:1, 1:2, 1:3, etc., and the molar ratio of the Ga source to the third solvent may be 1:100, 1:200, 1:300, etc. Thereby, GaS can be further facilitated_xAnd the formation of the cladding improves the fluorescence property and stability of the quantum dot product.

Further, after the second heating treatment is carried out on the solution of the precursor of the cladding reagent, AgInS is injected into the solution of the precursor of the cladding reagent₂Quantum dots and carrying out a second synthesis reaction to obtain AgInS₂/GaS_xAnd (4) quantum dot stock solution. By carrying out the second heating treatment, water and oxygen in the solution of the precursor of the cladding reagent can be effectively removed, and AgInS is injected rapidly₂Carrying out a second synthesis reaction on the quantum dots to obtain AgInS₂/GaS_xAnd (4) quantum dot stock solution.

According to some embodiments of the invention, according to AgInS₂The molar ratio of the quantum dots to the Ga source is 1 (1-50), and AgInS is injected into the solution of the precursor of the cladding reagent₂And (4) quantum dots. Specifically, AgInS₂The molar ratio of the quantum dots to the Ga source can be 1:1, 1:5, 1:10, 1:20. 1:30, 1:40, 1:50, etc. Therefore, the prepared quantum dot product has better fluorescence performance and stability.

The presence of water and oxygen is detrimental to the fluorescent properties of the quantum dots. By subjecting the cladding reagent precursor solution to the second heat treatment, water and oxygen therein can be efficiently removed. According to some embodiments of the present invention, the temperature used in the second heat treatment may be 120 to 130 ℃ (e.g., 120 ℃, 125 ℃, 130 ℃, etc.), and the time may be 30 to 60min (e.g., 30min, 40min, 50min, 60min, etc.). Therefore, the removal effect of water and oxygen in the cladding reagent precursor solution is better.

According to some embodiments of the present invention, the temperature used in the second synthesis reaction may be 200 to 300 ℃ (for example, 200 ℃, 210 ℃, 220 ℃, 250 ℃, 260 ℃, 280 ℃, 300 ℃, etc., preferably 200 to 250 ℃), the temperature increase rate may be 1 to 3 ℃/min (for example, 1 ℃/min, 1.5 ℃/min, 2 ℃/min, 2.5 ℃/min, 3 ℃/min, etc.), and the time may be 5 to 60min (for example, 5min, 10min, 20min, 40min, 60min, etc.). Therefore, the prepared quantum dot product has better fluorescence performance and stability.

In addition, the inventors found in their studies that the injection of AgInS into the encapsidation reagent precursor solution₂Before the quantum dots, the solution of the precursor of the cladding reagent is preferably heated to 200-250 ℃. If AgInS is injected at a lower temperature₂Quantum dots, albeit GaS_xGrowth of the shell layer also occurs, but GaS_xThe growth quality of the shell layer is poor, and the fluorescence performance and stability of the quantum dot product are influenced finally.

Further, according to an embodiment of the present invention, for AgInS₂/GaS_xCleaning the quantum dot stock solution to obtain AgInS₂/GaS_xAnd (4) quantum dots. Thus, impurities generated in the second synthesis reaction and some of the remaining raw materials can be effectively removed. Preferably, the supernatant is washed with ethanol several times (e.g., twice, three times, four times, etc.).

The invention will now be described with reference to specific examples, which are intended to be illustrative only and not to be limiting in any way.

Example 1

Preparation of mononuclear AgInS from silver acetate, indium acetate and N, N-dimethylthiourea₂Quantum dots, single core AgInS at 210 ℃₂Preparation of AgInS by quantum dot rapid injection into cladding mixture solution₂/GaS_xThe quantum dot comprises the following specific steps:

(1) preparation of cation precursor solution and anion precursor solution

Adding 0.4mmol of silver acetate, 0.4mmol of indium acetate, 1.2mmol of dodecyl mercaptan and 8mL of oleylamine into a 50mL three-neck flask to obtain a cation precursor solution; 0.8mmol of N, N-dimethylthiourea was dissolved in 4mL of ethanol at 60 ℃ to obtain a hot ethanol solution of N, N-dimethylthiourea.

(2) Mononuclear AgInS₂Preparation of quantum dots

Heating the cation precursor solution from room temperature to 130 ℃ under the protection of argon, keeping the temperature for 30min to remove water and oxygen in the precursor solution, then heating to 160 ℃, continuously dripping hot ethanol solution of the N, N-dimethylthiourea at the speed of 5mL/h, and reacting for 10min to obtain AgInS₂Putting the obtained mononuclear quantum dot stock solution into a centrifuge tube, centrifuging in a centrifuge at a rotation speed of 5000r/min for 5min to remove large particles, and cleaning the clear solution with anhydrous ethanol for 3 times to obtain mononuclear AgInS₂And (4) quantum dots.

(3)AgInS₂/GaS_xPreparation of quantum dots

0.1mmol of N, N-dimethylthiourea, 0.1mmol of gallium acetylacetonate and 8.0mL of octadecene were charged in a 50mL three-necked flask, and then the mixture solution was heated from room temperature to 120 ℃ and kept for 45min to remove water and oxygen from the precursor solution, and then the mixture solution was heated to 210 ℃ and rapidly injected with a solution containing 10. mu. mol of mononuclear AgInS₂The oleylamine solution of the quantum dots is heated to 280 ℃ at the heating rate of 2 ℃/min to carry out gallium sulfide (GaS)_x) Growing a shell layer, keeping the temperature at 280 ℃ for 5min, and then cooling the solution to room temperature to obtain AgInS₂the/GaSx quantum dot stock solution is added with anhydrous BAlcohol washing for 3 times to finally obtain AgInS₂/GaS_xAnd (4) quantum dots.

FIG. 1 is a mononuclear AgInS prepared in example 1₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectrum of quantum dot, mononuclear AgInS in the figure₂The quantum dot emission peak value is 715nm, the half-peak width is 123nm, and AgInS₂/GaS_xThe quantum dot emission peak value is 579nm, and the half-peak width is 41 nm.

Example 2

Preparation of mononuclear AgInS from silver acetate, indium acetate and thiourea₂Quantum dots, single core AgInS at 230 ℃₂Preparation of AgInS by quantum dot rapid injection into cladding mixture solution₂/GaS_xThe quantum dot comprises the following specific steps:

(1) preparation of cation precursor solution and anion precursor solution

Adding 0.4mmol of silver acetate, 0.4mmol of indium acetate, 1.2mmol of dodecyl mercaptan and 8mL of oleylamine into a 50mL three-neck flask to obtain a cation precursor solution; 0.8mmol of thiourea was dissolved in 4mL of ethanol at 70 ℃ to obtain a saturated solution of thiourea in hot ethanol.

(2) Mononuclear AgInS₂Preparation of quantum dots

Heating the cation precursor solution from room temperature to 120 ℃ under the protection of argon, keeping the temperature for 45min to remove water and oxygen in the precursor solution, then heating to 140 ℃, continuously dripping hot ethanol saturated solution of thiourea at the rate of 4mL/h, and reacting for 15min to obtain AgInS₂Putting the obtained mononuclear quantum dot stock solution into a centrifuge tube, centrifuging in a centrifuge to remove large particles at 7000r/min for 3min, and cleaning the clear solution with anhydrous ethanol for 3 times to obtain mononuclear AgInS₂And (4) quantum dots.

(3)AgInS₂/GaS_xPreparation of quantum dots

In a 50mL three-necked flask, 0.1mmol of N, N-dimethylthiourea, 0.1mmol of gallium acetylacetonate and 8.0mL of oleylamine were charged, and then the mixture solution was heated from room temperature to 120 ℃ for 45min to remove water and oxygen from the precursor solution, and then the mixture was subjected toThe solution is heated to 230 ℃ and rapidly injected with the mononuclear AgInS containing 10 mu mol₂The oleylamine solution of the quantum dots is heated to 280 ℃ at the heating rate of 2 ℃/min to carry out gallium sulfide (GaS)_x) Growing a shell layer, keeping the temperature at 280 ℃ for 5min, and then cooling the solution to room temperature to obtain AgInS₂the/GaSx quantum dot stock solution is washed for 3 times by absolute ethyl alcohol to finally obtain AgInS₂/GaS_xAnd (4) quantum dots.

FIG. 2 is a mononuclear AgInS prepared in example 2₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectrum of quantum dot, mononuclear AgInS in the figure₂The quantum dot emission peak value is 713nm, the half-peak width is 126nm, and AgInS₂/GaS_xThe quantum dot emission peak value is 575nm, and the half-peak width is 39.6 nm.

Example 3

Preparation of mononuclear AgInS from silver acetate, indium acetylacetonate and thiourea₂Quantum dots, single core AgInS at 230 ℃₂Preparation of AgInS by quantum dot rapid injection into cladding mixture solution₂/GaS_xThe quantum dot comprises the following specific steps:

(1) preparation of cation precursor solution and anion precursor solution

Adding 0.4mmol of silver acetate, 0.4mmol of indium acetylacetonate, 1.2mmol of dodecyl mercaptan and 8mL of oleylamine into a 50mL three-neck flask to obtain a cation precursor solution; 0.8mmol of thiourea was dissolved in 4mL of ethanol at 70 ℃ to obtain a saturated solution of thiourea in hot ethanol.

(2) Mononuclear AgInS₂Preparation of quantum dots

Heating the cation precursor solution from room temperature to 120 ℃ under the protection of argon, keeping the temperature for 45min to remove water and oxygen in the precursor solution, then heating to 160 ℃, continuously dripping hot ethanol saturated solution of thiourea at the rate of 4mL/h, and reacting for 15min to obtain AgInS₂Putting the obtained mononuclear quantum dot stock solution into a centrifuge tube, centrifuging in a centrifuge to remove large particles at 7000r/min for 3min, and cleaning the clear solution with anhydrous ethanol for 3 times to obtain mononuclear AgInS₂And (4) quantum dots.

(3)AgInS₂/GaS_xPreparation of quantum dots

Adding 0.1mmol N, N-dimethylthiourea, 0.1mmol gallium acetylacetonate and 10.0mL octadecene into a 50mL three-neck flask, heating the mixture solution from room temperature to 120 deg.C for 45min to remove water and oxygen from the precursor solution, heating the mixture solution to 230 deg.C, and rapidly injecting a solution containing 10. mu. mol mononuclear AgInS₂The oleylamine solution of the quantum dots is heated to 280 ℃ at the heating rate of 2 ℃/min to carry out gallium sulfide (GaS)_x) Growing a shell layer, keeping the temperature at 280 ℃ for 5min, and then cooling the solution to room temperature to obtain AgInS₂the/GaSx quantum dot stock solution is washed for 3 times by absolute ethyl alcohol to finally obtain AgInS₂/GaS_xAnd (4) quantum dots.

FIG. 3 is a mononuclear AgInS prepared in example 3₂Quantum dots and AgInS₂/GaS_xFluorescence emission spectrum of quantum dot, mononuclear AgInS in the figure₂The emission peak value of the quantum dot is 720nm, the half-peak width is 126nm, and AgInS₂The emission peak value of the/GaSx quantum dots is 577nm, and the half-peak width is 40.7 nm.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.