Preparation method of quantum dot, quantum dot and application of quantum dot

Abstract

The invention discloses a preparation method of a semiconductor nanocrystalline quantum dot, the quantum dot and application of the quantum dot, and relates to the technical field of quantum dot synthesis, the quantum dot is of a core-shell structure, the preparation method comprises preparation of a (Cu) AgInGaZnS core solution, preparation of an initial (Cu) AgInGaZnS / GaxS quantum dot and preparation of an ultimate (Cu) AgInGaZnS / GaxS quantum dot, and the preparation method of the (Cu) AgInGaZnS core solution comprises preparation of a (Cu) AgInGaZnS core solution. The preparation method comprises the following steps: mixing a (Cu source), an Ag source, an In source, a Ga source, a Zn source and an oleylamine solution, placing in a vacuum environment, completely dissolving, filling nitrogen to obtain a mixed precursor solution containing (Cu) Ag, In, Ga and Zn, dissolving sulfur powder in a mixed solution of oleylamine and octyl mercaptan, injecting the mixed precursor solution, carrying out primary heating and heat preservation to obtain an initial (Cu) AIGZS nuclear solution, carrying out primary cooling on the initial (Cu) AIGZS nuclear solution, carrying out secondary heating and heat preservation to obtain an initial (Cu) AIGZS nuclear solution, and carrying out secondary cooling on the initial (Cu) AIGZS nuclear solution. The preparation method comprises the following steps: injecting TOP (trioctylphosphine), preserving heat, and then cooling to room temperature to obtain a (Cu) AgInGaZnS core solution, and researching that a GaxS shell layer of the quantum dot is thicker, and the quantum dot is high in absorption capacity, efficient and pure in color.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum dot synthesis, in particular to a preparation method of quantum dots, quantum dots and their applications. Background Art

[0002] Environmentally friendly I-III-VI quantum dots and derivatives are expected to be ideal candidates for environmentally friendly materials to replace traditional Cd-based and Pb-based quantum dots due to their tunable band gaps that vary with composition, full visible light coverage, high efficiency, excellent stability and non-toxicity. In particular, the flexible tunability of their composition is very conducive to precisely controlling the energy band structure and microstructure.

[0003] I-III-VI quantum dots are more likely to split into sub-levels near the conduction band (CB) and valence band (VB), which often leads to asymmetric PL broadening and a higher density of defect states. The AIGS core shows obvious broadband emission characteristics, which originate from the defect-involved recombination process, and generally transform into band-edge emission after growing the Ga x S shell. However, even after growing the Ga x S, they still retain a significant level of defect emission, and the fluorescence quantum yield (PLQY) is not satisfactory. Summary of the Invention

[0004] To solve the above problems, the present invention proposes a preparation method of quantum dots, quantum dots and their applications. The purpose of the present invention is to synthesize (Cu)AgInGaS quantum dots with high absorption capacity, high efficiency and pure color. The specific content is as follows:

[0005] A kind of quantum dots, comprising the following components: 0.01 - 0.04 mol of CuCl, 0.1 - 0.2 mol of AgNO 3 , 0.05 - 0.2 mol of InCl 3 , 0.6 - 0.8 mol of Ga(acac) 3 , 0.03 - 0.1 mol of ZnCl 2 , 30.4 - 60.8 mol of oleylamine, 1.4 - 1.8 g of sulfur powder, 28.8 - 57.6 mol of octanethiol, 9 - 13.5 mol of TOP, 0.1 - 0.3 mol of Ga(DDTC) 3 , 0.3 - 0.6 mol of DMTU, 0.8 - 2.4 mol of GaCl 3 .

[0006] Preferably, the quantum dots include a core structure and a shell structure. The shell structure is a Ga x S shell layer, and the core structure is a (Cu)AgInGaZnS core.

[0007] Preferably, a preparation method of quantum dots includes:

[0008] S1. Preparation of (Cu)AgInGaZnS core solution;

[0009] S2. Preparation of initial (Cu)AgInGaZnS / Ga x S quantum dots;

[0010] S3. Preparation of final (Cu)AgInGaZnS / Ga x S quantum dots.

[0011] Preferably, the preparation of (Cu)AgInGaZnS core in S1 includes:

[0012] S101. Mix CuCl, AgNO 3 , InCl 3 , Ga(acac) 3 , ZnCl 2 with oleylamine solution and place it in a vacuum environment. After complete dissolution, fill it with nitrogen to obtain a mixed precursor solution containing Ag, In, Ga, and Zn;

[0013] S102. Dissolve sulfur powder in a mixed solution of oleylamine and octanethiol and inject it into the mixed precursor solution. After one-time heating and insulation, obtain an initial AIGZS core solution;

[0014] S103. After the initial (Cu)AIGZS core solution is cooled down once, inject TOP and keep it warm, and then cool it to room temperature to obtain (Cu)AgInGaZnS core solution. The role of TOP is to passivate the surface defects of the core quantum dots, suppress non-radiative transitions, and highlight the band-edge emission.

[0015] Preferably, the preparation of (Cu)AgInGaZnS / Ga x S quantum dots in S2 includes:

[0016] Dissolve Ga(acac) 3 , Ga(DDTC) 3 and DMTU in oleylamine solution, and inject it into (Cu)AgInGaZnS core solution under the condition of nitrogen environment. After secondary heating and insulation, obtain initial (Cu)AgInGaZnS / Ga x S quantum dots.

[0017] Preferably, the mass ratio of oleylamine solution to octanethiol mixed solution is 6.1:28.8;

[0018] AgNO 3 , InCl 3 , Ga(acac) 3 , ZnCl 2The molar ratios with the oleylamine solution are 0.12:0.05:0.8:0.03:61 and 0.2:0.2:0.6:0.03:61;

[0019] The mass ratio of sulfur powder, oleylamine solution and octanethiol mixed solution is 63.3:6.1:28.8;

[0020] Ga(acac) 3 、Ga(DDTC) 3 、The molar ratios of DMTU are 0.3:0.1:0.3 respectively.

[0021] Preferably, the content of the first heating and insulation is heating to 280 - 300 °C and insulating for 5 - 30 min;

[0022] After the first cooling, the content of injecting TOP and insulating is cooling to 180 - 200 °C, injecting TOP and insulating for 10 - 30 min;

[0023] The temperature range of the nitrogen environment is: 80 - 120 °C;

[0024] The specific content of the second heating and insulation is raising the temperature to 240 °C and insulating for 30 - 60 min.

[0025] Preferably, in S3, the preparation of the final (Cu)AgInGaZnS / Ga x S quantum dots includes:

[0026] S301. Inject the mixed precursor solution into the initial (Cu)AgInGaZnS / Ga x S quantum dots at the target temperature and heat;

[0027] The mixed precursor solution is a mixed precursor solution of Ga(acac) 3 、Ga(DDTC) 3 and DMTU dissolved in an oleylamine solution;

[0028] S302. Repeat S301 to obtain core / shell quantum dots with a grown final Ga x S shell layer;

[0029] S303. Inject GaCl 3 oleylamine solution at the target temperature and insulate, then cool to inject 4 mL of TOP and insulate, and then cool to room temperature;

[0030] Among them, in the GaCl 3 oleylamine solution, the molar ratio of GaCl 3 and OAm is 0.72:5.5 mmol, and its function is to promote shell layer growth;

[0031] TOP acts on in-situ passivation of surface defects of quantum dots, improving the fluorescence quantum yield (PLQY).

[0032] GaCl 3 The volume ratio of oleylamine solution to TOP is 1:2.2.

[0033] Ga(acac) dissolved in oleylamine solution in S301 3 , Ga(DDTC) 3 and the component percentages of the DMTU mixed precursor solution are 42.9:14.2:42.9;

[0034] The target temperature in S301 and S303 is 240 - 260 °C

[0035] Inject 0.4M GaCl 3 -OAm solution into S303 and keep the temperature for 30 - 60 min;

[0036] Cool down to inject TOP and keep the temperature, which is to cool down to 180 - 200 °C, inject 4 - 6 mL TOP and keep for 10 - 30 min.

[0037] Preferably, for the preparation application of a quantum dot, the quantum dot with high brightness and pure color is applied to the display field.

[0038] In summary, for the preparation method of a quantum dot, the quantum dot and its application of the present invention, compared with the traditional technology, the passivation of the core surface defects by in-situ treatment based on trioctylphosphine (TOP) of the present invention is very effective, resulting in the great suppression of the edge tail emission. At the same time, due to the effective surface passivation of the heteroepitaxial growth of the Ga x S shell layer, the AgInGaZnS / Ga x S quantum dots show bright and sharp emission (the green light quantum yield is 80%, the full width at half maximum is 33 nm; the blue light quantum yield is 68%, the full width at half maximum is 24 nm) and completely suppressed defect emission. In addition, the present invention adds Cu element on the basis of AgInGaZnS quantum dots to obtain a CuAgInGaZnS alloy quantum dot with high entropy characteristics, and obtains a red light (630 nm) quantum dot with a PL QY of 96% and a full width at half maximum of 60 nm after growing the GaS shell layer.

[0039] The technical method of the present invention will be further described in detail below with reference to the drawings and embodiments. Description of the Drawings

[0040] Figure 1 It is the absorption and photoluminescence spectra of AIGZS and AIGZS / GS of sample ID 1 of the present invention, Figure 1 in which (a) is the absorption spectrum of AIGZS and AIGZS / GS, Figure 1In (b) is the AIGZS, AIGZS / GS photoluminescence spectrogram;

[0041] Figure 2 This is the TEM image of AIGZS and AIGZS / GS of Sample ID 1 of the present invention. Figure 2 In (a) is the AIGZS core. Figure 2 In (b) is the primary AIGZS / GS. Figure 2 In (c) is the final AIGZS / GS.

[0042] Figure 3 This is the absorption and photoluminescence spectrograms of AIGZS and AIGZS / GS of Sample ID 2 of the present invention. Figure 3 In (a) is the AIGZS, AIGZS / GS absorption spectrogram. Figure 3 In (b) is the AIGZS, AIGZS / GS photoluminescence spectrogram.

[0043] Figure 4 This is the TEM image of AIGZS and AIGZS / GS of Sample ID 2 of the present invention. Figure 4 In (a) is the AIGZS core. Figure 4 In (b) is the primary AIGZS / GS. Figure 4 In (c) is the intermediate AIGZS / GS. Figure 4 In (d) is the final AIGZS / GS.

[0044] Figure 5 This is the photoluminescence spectrograms of AIGZS core of Samples ID 1, 2, and 3 of the present invention before and after being treated with TOP. Figure 5 In (a) is Sample ID 1. Figure 5 In (b) is Sample ID 2. Figure 5 In (c) is Sample ID 3.

[0045] Figure 6 This is the absorption and photoluminescence spectrograms of the final AIGZS / GS of Sample ID 3 of the present invention. Figure 6 In (a) is the absorption spectrogram. Figure 6 In (b) is the photoluminescence spectrogram.

[0046] Figure 7 This is the absorption and photoluminescence spectrograms of CAIGZS and CAIGZS / GS of Sample ID 4 of the present invention. Figure 7 In (a) is the CAIGZS, CAIGZS / GS absorption spectrogram. Figure 1 In (b) is the CAIGZS, CAIGZS / GS photoluminescence spectrogram.

[0047] Figure 8 This is a high-resolution TEM image of the CAIGZS core of sample ID 4 of the present invention. Detailed implementation manners

[0048] The technical method of the present invention will be further described below with reference to the accompanying drawings and embodiments. It should be noted that: unless otherwise specifically stated, the relative arrangements, numerical expressions, and numerical values of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0049] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present invention or its application or use.

[0050] Technologies, systems, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the technologies, systems, and devices should be regarded as part of the specification.

[0051] In all the examples shown and discussed here, any specific values should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0052] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meaning as understood by those of ordinary skill in the field to which the present invention pertains.

[0053] The present invention provides a method for preparing quantum dots, quantum dots, and their applications, including that the quantum dots are of a core-shell structure, and the preparation method includes the preparation of a (Cu)AgInGaZnS core solution, the preparation of initial (Cu)AgInGaZnS / Ga x S quantum dots, and the preparation of final (Cu)AgInGaZnS / Ga x S quantum dots. The method for preparing the (Cu)AgInGaZnS core solution includes mixing a (Cu source), an Ag source, an In source, a Ga source, a Zn source (such as: CuCl, AgNO 3 ; InCl 3 ; Ga(acac) 3 , ZnCl 2 ) and an oleylamine solution and placing them in a vacuum environment. After complete dissolution, nitrogen is filled to obtain a mixed precursor solution containing (Cu)AgInGaZn. Sulfur powder is dissolved in a mixed solution of oleylamine and octanethiol and injected into the mixed precursor solution. After one-time heating and insulation, an initial (Cu)AIGZS core solution is obtained. After the initial (Cu)AIGZS core solution is cooled once, trioctylphosphine (TOP) is injected and kept warm, and then cooled to room temperature to obtain a (Cu)AgInGaZnS core solution. The present invention studies the Ga of quantum dots xThe S shell is thicker, with high absorption capacity, high efficiency, and pure color. The specific embodiments are as follows:

[0054] Example 1

[0055] Preparation of AgInGaZnS core solution

[0056] Sample ID 1 was prepared using the following typical synthesis of AgInGaZnS core: 0.12 mmol of 0.006 M AgNO 3 , 0.05 mmol of 0.0025 M InCl 3 , 0.8 mmol of 0.04 M Ga(acac) 3 , 0.03 mmol of 0.0015 M ZnCl 2 were mixed with 20 mL of oleylamine solution and placed in a 100 mL three-necked flask for degassing and vacuum pumping. After the powder was completely dissolved, nitrogen was filled into the flask.

[0057] 1.6 mmol of sulfur powder was dissolved in a mixed solution of 2 mL of oleylamine and 5 mL of octanethiol and loaded into an airtight syringe. Then, the temperature was raised to 280 °C and kept for 30 minutes. After removing the heating jacket, the solution was cooled to 180 °C.

[0058] 4 mL of TOP was injected and kept for 20 min, and then cooled to room temperature.

[0059] Samples ID 2 and 3 were also synthesized using this method. Only the ratio of In source and Ga source was changed. Sample ID 2 used 0.2 mmol of 0.01 M InCl 3 , 0.6 mmol of 0.03 M Ga(acac) 3 , and sample ID 3 used 0.3 mmol of 0.015 M InCl 3 , 0.3 mmol of 0.015 M Ga(acac) 3 . The optical property measurements of the AgInGaZnS core are summarized in Table 1.

[0060] Table 1

[0061] Sample ID Wavelength (nm) In / (In + Ga) 1 480 / 583 1 / 17 2 530 / 684 1 / 4 3 541 / 624 1 / 2

[0062] Example 2

[0063] Preparation of AgInGaZnS / Ga x S:

[0064] 0.3 mmol of Ga(acac) 3 gallium acetylacetonate, 0.1 mmol of Ga(DDTC) 3Gallium diethyldithiocarbamate and 0.3 mmol of DMTU (N,N-dimethylthiourea) were dissolved in 10 mL of oleylamine solution. The solution was injected into the core solutions of Samples 1, 2, and 3 at 90 °C under a nitrogen atmosphere. The temperature was then raised to 240 °C and held for 30 min.

[0065] To obtain a thicker Ga x S shell, a precursor solution containing 0.3 mmol of Ga(acac) 3 , 0.1 mmol of Ga(DDTC) 3 and 0.3 mmol of DMTU dissolved in 2 mL of oleylamine solution was injected at 260 °C for 30 minutes of heating.

[0066] The above steps were repeated to obtain core / shell quantum dots with a Ga x S shell grown three times. Subsequently, 2 mL of a 0.4 M GaCl 3 oleylamine solution was injected at 260 °C and held for 30 min. Finally, the temperature was lowered to 180 °C, 4 mL of TOP was injected and held for 20 min, and then it was cooled to room temperature. The optical properties of the AgInGaZnS / Ga x S material are summarized in Table 2.

[0067] Table 2

[0068] Sample ID Wavelength (nm) Full Width at Half Maximum (nm) Fluorescence Quantum Yield (%) 1 480 24 68 2 530 33 80 3 540 33 90

[0069] Example 3

[0070] In-situ surface treatment with trioctylphosphine (TOP) and promotion of shell growth by gallium chloride

[0071] The surface modification of the AgInGaZnS core was carried out by directly adding a trioctylphosphine solution to the quantum dot stock solution and holding it at 180 °C for 10 - 30 minutes. This treatment led to a significant enhancement of the band-edge emission of the core, as Figure 5 shown. The role of gallium chloride is to promote the continuous growth of the Ga x S shell, as reflected by the continuously narrowing full width at half maximum, and finally the average diameter of the AIGZS / GS core / shell quantum dots is about 10 nm.

[0072] Example 4

[0073] Preparation of CuAgInGaZnS core and its CuAgInGaZnS / Ga x S

[0074] Sample ID 4 was prepared using the following synthesis: 0.02 mmol of 0.001 M CuCl, 0.1 mmol of 0.005 M AgNO 3 , 0.2 mmol of 0.01 M InCl3 , 0.8 mmol of 0.04 M Ga(acac) 3 , 0.06 mmol of 0.003 M ZnCl 2 is mixed with 20 mL of oleylamine solution, and the remaining nucleation conditions are exactly the same as those of sample IDs 1, 2, and 3, and the growth of the Ga x S shell is also exactly the same as that of sample IDs 1, 2, and 3. The optical properties of the CuAgInGaZnS / Ga x S material are summarized in Table 3. The elemental contents of all elements in the CuAgInGaZnS core monitored by energy-dispersive X-ray spectroscopy (EDS) are summarized in Table 4.

[0075] Table 3

[0076] Sample ID4 Wavelength (nm) Full Width at Half Maximum (nm) Fluorescence Quantum Yield (%) CAIGZS 646 150 - Primary CAIGZS / GS 614 75 - Intermediate CAIGZS / GS 621 62 - Final CAIGZS / GS 630 60 96

[0077] Table 4

[0078] Element Content (%) S 48.1 Cu 4.6 Zn 1.6 Ga 18.3 Ag 16.1 In 11.3

[0079] As Figure 1 shown. The in-situ treatment based on TOP is very effective in passivating the surface defects of the core, resulting in the dominant tail emission and the significant suppression of the edge tail emission. At the same time, due to the effective surface passivation of the heteroepitaxial growth of the Ga x S shell, the sample ID 1 AIGZS / GS core / shell QDs show bright and sharp emission at 480 nm (PL QY is 68%, FWHM is about 24 nm) and completely suppressed tail emission. In addition, the present invention observes the morphology of core-shell quantum dots with different growth times of Ga x S by TEM.

[0080] As Figure 2 shown, the sample ID 1 particles have good uniformity and monodispersity, and the corresponding particle size is 7.4, 8.0, and 10.4 nm, respectively.

[0081] As Figure 3 shown, the in-situ passivation of defects by TOP and the continuous growth of the Ga x S shell result in the enhancement of the PL QY and the continuous narrowing of the full width at half maximum of the green AIGZS / GS core-shell quantum dots. Finally, the PL QY and FWHM of the sample ID 2 AIGZS / GS core-shell quantum dots at 530 nm are 80% and 33 nm, respectively. As Figure 4 shown, the sample ID 2 particles have good uniformity and monodispersity, and the corresponding particle size is 7.3, 8.4, 9.2, and 10.3 nm, respectively.

[0082] As Figure 5As shown, the edge emissions of the samples with IDs 1, 2, and 3 AIGZS nuclei were significantly enhanced after the surface defects were treated in situ by TOP.

[0083] As Figure 6 shown, the PL QY and FWHM of the sample with ID 3 AIGZS / GS core-shell quantum dots at 540 nm were 90% and 33 nm, respectively.

[0084] As Figure 7 shown, the PL QY and FWHM of the sample with ID 4 CAIGZS / GS core-shell quantum dots at 630 nm were 96% and 60 nm, respectively. As Figure 8 shown, the sample with ID 4 had good uniformity and monodispersity, and the corresponding particle size was 13.5 nm.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical method of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify the technical method of the present invention or make equivalent substitutions, and these modifications or equivalent substitutions cannot make the modified technical method deviate from the spirit and scope of the technical method of the present invention.

Claims

1. A quantum dot, characterized in that: It includes the following components: 0.01-0.04 mol CuCl, 0.1-0.2 mol AgNO3, 0.05-0.2 mol InCl3, 0.6-0.8 mol Ga(acac)3, 0.03-0.1 mol ZnCl2, 30.4-60.8 mol oleylamine, 1.4-1.8 g sulfur powder, 28.8-57.6 mol octanethiol, 9-13.5 mol TOP, 0.1-0.3 mol Ga(DDTC)3, 0.3-0.6 mol DMTU and 0.8-2.4 mol GaCl3.

2. A quantum dot according to claim 1, characterized in that: The quantum dot comprises a core structure and a shell structure, wherein the shell structure is Ga x S shell layer, the core structure is a (Cu)AgInGaZnS core.

3. A method for preparing quantum dots according to any one of claims 1 to 2, characterized in that: include: S1. Preparation of (Cu)AgInGaZnS core solution; S2, initial (Cu)AgInGaZnS / Ga x Preparation of S quantum dots; S3, Ultimate (Cu)AgInGaZnS / Ga x Preparation of S quantum dots.

4. The method for preparing quantum dots according to claim 3, characterized in that: The preparation of (Cu)AgInGaZnS core in S1 includes: S101, mixing CuCl, AgNO3, InCl3, Ga(acac)3, ZnCl2 and oleylamine solution and placing them in a vacuum environment, and after they are completely dissolved, filling with nitrogen to obtain a mixed precursor solution containing Ag In Ga Zn; S102, dissolving sulfur powder in a mixed solution of oleylamine and octanol and injecting the mixed precursor solution, heating and keeping the temperature once to obtain an initial AIGZS core solution; S103. After the initial (Cu)AIGZS core solution is cooled once, TOP is injected and kept warm, and then cooled to room temperature to obtain a (Cu)AgInGaZnS core solution.

5. The method for preparing quantum dots according to claim 4, characterized in that: (Cu)AgInGaZnS / Ga in S2 x The preparation of S quantum dots includes: Ga(acac)3, Ga(DDTC)3 and DMTU were dissolved in oleylamine solution, injected into (Cu)AgInGaZnS core solution under nitrogen environment, heated and kept warm for a second time to obtain the initial (Cu)AgInGaZnS / Ga x S quantum dots.

6. The method for preparing quantum dots according to claim 5, characterized in that: The mass ratio of oleylamine solution to octanethiol mixed solution is 6.1:28.8; The molar ratios of AgNO3, InCl3, Ga(acac)3, ZnCl2 and oleylamine solution were 0.12:0.05:0.8:0.03:61 and 0.2:0.2:0.6:0.03:61; The mass ratio of sulfur powder, oleylamine solution and octanol mixed solution is 63.3:6.1:28.8; The molar ratios of Ga(acac)3, Ga(DDTC)3, and DMTU are 0.3:0.1:0.3, respectively.

7. The method for preparing quantum dots according to claim 6, characterized in that: The contents of the first heating and heat preservation are heating to 280-300℃ and heat preservation for 5-30min; After the first cooling, the contents of injecting trioctylphosphine TOP and keeping the temperature are cooling to 180-200℃, injecting TOP and keeping the temperature for 10-30min; The temperature range of nitrogen environment is: 80-120℃; The specific content of the secondary heating and heat preservation is that the temperature is raised to 240-260°C and kept warm for 30-60 minutes.

8. The method for preparing quantum dots according to claim 6, characterized in that: Ultimate (Cu)AgInGaZnS / Ga in S3 x The preparation of S quantum dots includes: S301, injecting the mixed precursor solution into the initial (Cu)AgInGaZnS / Ga at the target temperature x S quantum dots and heated; The mixed precursor solution is a mixed precursor solution of Ga(acac)3, Ga(DDTC)3 and DMTU dissolved in an oleylamine solution; Among them, the component percentages of the mixed precursor solution of Ga(acac)3, Ga(DDTC)3 and DMTU dissolved in the oleylamine solution are 42.9:14.2:42.9; S302, repeat S301 to grow the ultimate Ga x S-shell core / shell quantum dots; S303, injecting GaCl3 oleylamine solution at the target temperature and keeping the temperature, then cooling to injecting trioctylphosphine (TOP) and keeping the temperature, and then cooling to room temperature; Wherein, the molar ratio of GaCl3 to oleylamine in the GaCl3 oleylamine solution is 0.72:5.5; The volume ratio of GaCl3 oleylamine solution and TOP is 1:2.

2.

9. The method for preparing quantum dots according to claim 8, characterized in that: ； The target temperature in S301 and S303 is 240-260°C; Inject 0.4M GaCl3 oleylamine solution into S303 and keep it warm for 30-60min; The steps of cooling down to injecting 4-6 mL TOP and keeping the temperature are cooling down to 180-200° C., injecting 4-6 mL TOP and keeping the temperature for 10-30 minutes.

10. An application of the quantum dots according to any one of claims 1 to 2 in the field of display devices and QLEDs.

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