Method for synthesizing perovskite quantum dots by using low-temperature polar solvent

Abstract

The invention discloses a method for synthesizing CsPbX3 perovskite quantum dots by using a low-temperature polar solvent, which comprises the following steps: 1) preparing a cationic precursor: taking a corresponding required amount of acetate, adding the polar solvent, and taking octanoic acid as a solvent; 2) preparing an anion precursor: taking a polar solvent as a solvent, and adding corresponding halogen acid and oleylamine; and (3) mixing the anion precursor and the cation precursor, adding a certain amount of non-polar solvent during mixing, adding the non-polar solvent during mixing or during preparation of a precursor solution, and stirring and reacting to obtain the perovskite quantum dots, wherein the volume ratio of the non-polar solvent to the polar solvent is 1: 3. The synthetic method has the advantages of high yield, simplicity, low cost and continuous and adjustable light color.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of all-inorganic metal perovskite quantum dots, and relates to a method for synthesizing perovskite quantum dots using a low-temperature polar solvent. Background Art

[0002] In recent years, all-inorganic metal halide perovskites have demonstrated excellent performance in various optoelectronic devices due to their unique material properties. They have received widespread attention and made great research progress in the fields of solar cells, photodetectors, lasers and photocatalysis.

[0003] All-inorganic metal halide perovskite CsPbX3 (X=Cl\Br\I) perovskite quantum dots have rapidly emerged as a key material for breaking through the bottleneck of X-ray ultrafast imaging technology (Nat Commun. 2024, 15, 8870) due to their unique short luminescence lifetime, high X-ray absorption coefficient, large Stokes shift, excellent carrier mobility, good defect tolerance, and adjustable structure and properties (Nature. 2018, 561, 88-93).

[0004] At present, there are two main methods for preparing CsPbX3 (X=Cl\Br\I) perovskite quantum dots: hot injection method and anti-solvent method. The hot injection method has high luminescence efficiency, but its cost is high, the synthesis conditions are harsh, and the yield is low; although the anti-solvent method solves the problem of harsh synthesis conditions while maintaining high luminescence efficiency, its own yield is still extremely low. The reaction environment of the above two methods is non-polar solvent, and it is always unable to effectively increase the yield. Simply replacing the reaction reagents with polar ones cannot successfully synthesize perovskite quantum dots.

[0005] Therefore, developing a method for synthesizing CsPbX3 (X=Cl\Br\I) perovskite quantum dots with high yield, low cost and simple process while ensuring high luminous efficiency has become an urgent problem to be solved. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing CsPbX3 (X = Cl\Br\I) perovskite quantum dots by a solution method. The method can prepare a large amount of perovskite quantum dots in a polar solvent at low temperature and normal pressure, and has a simple process and low cost.

[0007] The technical solution for implementing the present invention is as follows:

[0008] A method for synthesizing CsPbX3 perovskite quantum dots using a low-temperature polar solvent comprises the following steps:

[0009] Step 1, adding a Cs source, a Pb source, and an organic acid into a polar solvent, stirring at room temperature until dissolved, to obtain a cationic precursor solution;

[0010] Step 2, adding the X source and the ligand to a polar solvent, stirring at room temperature, to obtain an anion precursor solution; Step 3, mixing the above two precursor solutions to prepare a quantum dot crude solution, wherein during the mixing process, the stirring speed is set to 600 rpm, the temperature is 0-5°C, and the reaction time is 1 minute;

[0011] Step 4, purifying the crude quantum dot solution obtained in step 3, centrifuging and dispersing, and taking the supernatant by centrifugation to obtain a CsPbX3 perovskite quantum dot solution.

[0012] Preferably, in steps 1 and 2, the polar solvent can be any one of toluene, n-butanol, ethyl acetate, acetone, isopropanol, ethanol, methanol, etc., preferably ethyl acetate, isopropanol, methanol, and more preferably methanol.

[0013] Preferably, in step 1, the Cs source is CsAc, and the Pb source is PbAc2.

[0014] Preferably, in step 1, the organic acid can be any one of formic acid, acetic acid, octanoic acid, 2-ethyldecanoic acid, and oleic acid, preferably octanoic acid.

[0015] Preferably, the molar ratio of the Cs source, the Pb source and the X source is 1:1:6; the molar ratio of the ligand and the X source is 1:1; and the molar ratio of the organic acid and the Cs source is 3:1.

[0016] Preferably, the X source is any one or two of HI, HBr, and HCl.

[0017] Preferably, the ligand is oleylamine.

[0018] Preferably, in step 3, the two precursor solutions are mixed and a certain amount of non-polar solvent is added. The non-polar solvent can be added during mixing or when preparing the cationic precursor solution or the anionic precursor solution. The volume ratio of the non-polar solvent to the polar solvent is 1:3.

[0019] Specifically, the non-polar solvent may be any one of n-hexane, n-octane and toluene.

[0020] Preferably, in step 4, the crude quantum dot solution is purified by adding three times the volume of ethyl acetate, the precipitate is obtained by centrifugation, n-hexane is added for dispersion, and the supernatant is obtained by centrifugation to obtain the CsPbX3 perovskite quantum dot solution.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] (1) The present invention can achieve low-cost and high-yield synthesis of CsPbX3 (X=Cl\Br\I) perovskite quantum dots while maintaining high luminescence efficiency and low self-absorption effect. Compared with common perovskite quantum dot synthesis methods, such as hot injection and anti-solvent method, the present invention is simple to operate, low-cost, and can be scaled up proportionally according to demand. It has the potential for large-scale industrial application and can easily prepare large-area perovskite scintillator films that meet the requirements of ultrafast X-ray imaging.

[0023] (2) The present invention can achieve size control of perovskite quantum dots and change their luminescent color by selecting polar solvents with different polarities, and has great universality in the synthesis of perovskite quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Comparison of the yields of CsPbBr3 perovskite quantum dots prepared in Example 1 of the present invention and Comparative Example 1.

[0025] Figure 2 1 is the XRD diagram of the CsPbBr3 perovskite quantum dots prepared in Example 1 and Comparative Example 1 of the present invention.

[0026] Figure 3 The photoluminescence and absorption spectra of the CsPbBr3 perovskite quantum dots prepared in Example 1 and Comparative Example 1 of the present invention are shown.

[0027] Figure 4 The photoluminescence spectra of CsPbBr3, CsPbCl3, and CsPbI3 perovskite quantum dots prepared in Examples 1, 2, and 3 of the present invention are shown.

[0028] Figure 5 Graph showing the photoluminescence spectra of the CsPbBr3 perovskite quantum dots prepared in Examples 4, 5 and 6 of the present invention.

[0029] Figure 6 Graph showing the photoluminescence spectra of the CsPbBr3 perovskite quantum dots prepared in Examples 7 and 8 of the present invention.

[0030] Figure 7 This is a comparison diagram of the CsPbBr3 perovskite quantum dot crude solutions prepared in Example 1 and Example 9 of the present invention.

[0031] Figure 8 Graphs showing the photoluminescence and absorption spectra of the CsPbBr3 perovskite quantum dots prepared in Examples 10 and 11 of the present invention.

[0032] Fig. 9 Graphs showing the photoluminescence and absorption spectra of the CsPbBr3 perovskite quantum dots prepared in Examples 12 and 13 of the present invention.

[0033] Fig.10 Graph showing the photoluminescence and absorption spectra of the CsPbBr3 perovskite quantum dots prepared in Example 14 of the present invention.

[0034] Fig.11 This is a photoluminescence spectrum of the CsPbBr3 perovskite quantum dots prepared in Example 15 and Example 16 of the present invention.

[0035] Fig.12 This is a photoluminescence spectrum of the CsPbBr3 perovskite quantum dots prepared in Example 17 and Example 18 of the present invention.

[0036] Fig.13 This is a photoluminescence spectrum of the CsPbBr3 perovskite quantum dots prepared in Example 19 of the present invention.

[0037] Fig.14 This is a comparison chart of the luminescence of CsPbBr3 perovskite quantum dots prepared in Comparative Examples 1, 2, 3, and 4 of the present invention.

[0038] Fig.15 It is a comparison diagram of the irradiated luminescence images of the CsPbBr3 perovskite quantum dot scintillator film prepared in Example 1 of the present invention and Comparative Example 1.

[0039] Fig.16 This is a comparison diagram of standard X-ray imaging resolution card images taken in Example 1 of the present invention and Comparative Example 1.

[0040] Fig.17 This is a diagram of the CsPbBr3 perovskite quantum dot solution prepared in Example 1 of the present invention.

[0041] Fig.18 This is a picture of a scintillator film prepared by spraying the CsPbBr3 perovskite quantum dot solution prepared in Example 1 of the present invention.

[0042] Fig.19 This is an actual imaging effect diagram of the scintillator thin film sample prepared by spraying the CsPbBr3 perovskite quantum dot solution prepared in Example 1 of the present invention, when it is placed in the imaging light path for sample photography.

[0043] Fig. 20 This is a luminescence comparison diagram of CsPbCl3, CsPbBr3, and CsPbI3 perovskite quantum dot solutions prepared in Examples 1, 2, and 3 of the present invention. DETAILED DESCRIPTION

[0044] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application belongs; the term "and / or" used herein includes any and all combinations of one or more of the associated listed items.

[0046] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0047] As used herein, the term "about" is used to provide flexibility and imprecision associated with a given term, measurement or value. The degree of flexibility for a particular variable can be easily determined by one skilled in the art.

[0048] As used herein, the term "at least one of" is intended to be synonymous with "one or more of." For example, "at least one of A, B, and C" expressly includes only A, only B, only C, and combinations of each thereof.

[0049] The current mainstream synthesis of CsPbX3 (X = Cl\Br\I) perovskite quantum dots still uses non-polar solvents as the main medium for liquid phase synthesis, resulting in the inability to effectively increase the synthesis concentration of perovskite quantum dots. By using polar solvents, the physical properties of the cationic precursor concentration can be effectively improved. It is used as the main medium for liquid phase synthesis, and a small amount of non-polar solvent is added to it to adjust the polarity of the solution. Octanoic acid is added to promote the fusion of polar solvents and non-polar solvents. The reused hydrohalic acid provides high-concentration anions, and oleylamine is added as a stabilizing ligand. CsPbX3 (X = Cl\Br\I) perovskite quantum dots with high yield and high luminescence efficiency at low temperature and normal pressure have been developed to meet the needs of low-cost production.

[0050] Example 1

[0051] Synthesis of CsPbBr3 perovskite quantum dots (LT-Br-QDs) in polar solvents. Preparation of precursors for perovskite quantum dots synthesized in polar solvents: 1) Cationic precursors: add 1mmol cesium acetate (CsAc, 192mg), 1mmol lead acetate (Pb(AC)2-3H2O, 0.380mg), 3mmol octanoic acid (C8COOH, volume about 0.48mL), 6mL methanol (Met), 3ml n-hexane (HEX) in a 20ml glass sample bottle, and stir at room temperature (600rpm) until completely dissolved. 2) Anionic precursors: add 6mmol oleylamine (C8COOH, volume about 0.48mL), 6mL methanol (Met), 3ml n-hexane (HEX) in 3ml Met. 18 NH2, volume is about 2mL), 6mmol hydrobromic acid (HBr, 48Wt% in H2O, volume is about 0.68mL), stir until the reaction is complete, and let it stand until the solution returns to room temperature.

[0052] The cation precursor solution was stirred rapidly (600 rpm) in a low-temperature reactor, and the anion precursor solution was quickly injected. The stirring was continued for 1 minute to obtain a crude emerald green nanocrystal solution. The crude solution was mixed with ethyl acetate in a ratio of 1:3, centrifuged at 9000 rpm for 2 minutes, and the supernatant was discarded. The precipitate was dispersed in n-hexane, and the supernatant was obtained by centrifugation again to obtain a CsPbBr3 perovskite quantum dot solution, such as Fig.17 As shown, the quantum dots are named LT-Br-QDs.

[0053] Using a sprayer, the LT-Br-QDs solution is sprayed into a CsPbBr3 perovskite scintillator film, such as Fig.18 As shown. And put it into the imaging light path to perform actual sample imaging, as shown Fig.19 shown.

[0054] Example 2

[0055] Synthesis of CsPbCl3 perovskite quantum dots (LT-Cl-QDs) in polar solvents. This example is basically the same as Example 1, except that the hydrobromic acid added to the anion precursor solution is replaced with hydrochloric acid, and is named LT-Cl-QDs.

[0056] Example 3

[0057] Synthesis of CsPbI3 perovskite quantum dots (LT-I-QDs) in polar solvents This example is basically the same as Example 1, except that the hydrobromic acid added to the anion precursor solution is replaced with hydroiodic acid, and is named LT-I-QDs.

[0058] Example 4

[0059] This example is basically the same as Example 1, the only difference being that the polar solvent methanol in the reaction is replaced with toluene.

[0060] Example 5

[0061] This example is basically the same as Example 1, the only difference being that the polar solvent methanol in the reaction is replaced with n-butanol.

[0062] Example 6

[0063] This example is basically the same as Example 1, except that the polar solvent methanol in the reaction is replaced with ethyl acetate.

[0064] Example 7

[0065] This embodiment is basically the same as embodiment 1, the only difference being that the polar solvent methanol in the reaction is replaced with acetone.

[0066] Example 8

[0067] This example is basically the same as Example 1, except that the polar solvent methanol in the reaction is replaced with isopropanol.

[0068] Example 9

[0069] This embodiment is basically the same as embodiment 1, the only difference being that the reaction temperature is room temperature (about 20° C.).

[0070] Example 10

[0071] This example is basically the same as Example 1, except that the amount of the non-polar solvent n-hexane in the reaction is reduced to 0 ml.

[0072] Embodiment 11

[0073] This example is basically the same as Example 1, except that the amount of the non-polar solvent n-hexane in the reaction is reduced to 1 ml.

[0074] Example 12

[0075] This example is basically the same as Example 1, except that the amount of the non-polar solvent n-hexane in the reaction is reduced to 2 ml.

[0076] Example 13

[0077] This example is basically the same as Example 1, except that the amount of the non-polar solvent n-hexane in the reaction is increased to 4 ml.

[0078] Embodiment 14

[0079] This example is basically the same as Example 1, except that the amount of the non-polar solvent n-hexane in the reaction is increased to 5 ml.

[0080] Embodiment 15

[0081] This embodiment is substantially the same as embodiment 1, the only difference being that the octanoic acid in the reaction is replaced by formic acid.

[0082] Example 16

[0083] This embodiment is substantially the same as embodiment 1, except that octanoic acid in the reaction is replaced with acetic acid.

[0084] Embodiment 17

[0085] This embodiment is substantially the same as embodiment 1, the only difference being that octanoic acid in the reaction is replaced with propionic acid.

[0086] Embodiment 18

[0087] This example is basically the same as Example 1, except that the octanoic acid in the reaction is replaced with 2-ethyldecanoic acid.

[0088] Embodiment 29

[0089] This example is basically the same as Example 1, except that octanoic acid in the reaction is replaced by oleic acid.

[0090] Comparative Example 1

[0091] Preparation of cesium oleate (OA-Cs) precursor: Take 1mL of oleic acid, 10mL of octadecene, and 0.36g of cesium carbonate, and add them to a three-necked flask with a capacity of 100mL in sequence. First, pass argon for 5min to initially expel the oxygen and water in the three-necked flask, and then stir and heat to 120℃ for reaction. In order to completely dissolve the solution, after maintaining it at 120℃ for five minutes, argon is immediately passed into the other vent port of the three-necked flask, and the temperature is continued to rise to 150℃ and stabilize the reaction for 10 minutes. Then quickly take out the OA-Cs precursor with a pipette and put it into a glass bottle for storage. Since the solubility of OA-Cs solution decreases after cooling and turns into a milky white suspension, it needs to be heated and dissolved in advance during subsequent hot injection for easy injection.

[0092] CsPbBr3 quantum dots (HI-QDs) were synthesized by hot injection. PbBr2 (0.2 g), OA (1.5 mL), OAm (1.5 mL) and ODE (15 mL) were added to a 100 mL three-necked flask. After continuous stirring with argon for 5 min, the temperature was continuously raised to 120 ° C and heated for 20 min. After the PbBr2 powder was completely dissolved, it was continued to be heated to 160 ° C for 10 min. Subsequently, the cesium oleate precursor (2 mL) dissolved by heating was quickly injected into the three-necked flask, reacted for 5 s and immediately taken out, and stirred in an ice bath to quickly cool it down to obtain a yellow-green crude solution. The crude solution and ethyl acetate were mixed in a ratio of 1:3, centrifuged at 9000 rpm for 2 min, and the supernatant was discarded. The precipitate was dispersed in n-hexane, and the supernatant was taken out by centrifugation again to obtain a CsPbBr3 quantum dot solution, and the quantum dots were named HI-QDs.

[0093] Comparative Example 2

[0094] Antisolvent method: PbBr2 (0.4 mmol) and CsBr (0.4 mmol) were dissolved in DMF (10 mL). OA (1 mL) and OAm (0.5 mL) were added to stabilize the precursor solution. Then, 1 mL of the precursor solution was quickly added to toluene (10 mL) under vigorous stirring. A strong green emission was observed immediately after injection, and the quantum dots named RT-QDs were obtained.

[0095] Comparative Example 3

[0096] This comparative example is basically the same as comparative example 1, the only difference being that the concentrations of Cs, Pb, and Br in the reaction are proportionally increased by five times.

[0097] Comparative Example 4

[0098] This comparative example is basically the same as comparative example 2, the only difference being that the concentrations of Cs, Pb, and Br in the reaction are proportionally increased by five times.

[0099] Performance Testing

[0100] 1. Output comparison

[0101] The yields of the CsPbBr3 quantum dot samples prepared in Example 1 and Comparative Example 1 were compared, and the results are as follows: Figure 1 As shown, by the formula: yield = CsPbBr3 quantum dot mass / solution volume, it can be observed that the yield of CsPbBr3 quantum dots synthesized by the method of the present invention is 127.77 mg / ml, which is more than twenty times the yield of 6.92 mg / ml by the hot injection method. In comparative example 2, due to the low yield, centrifugal drying and weighing are impossible, but its actual yield is also much lower than that of the hot injection method.

[0102] 2. X-ray diffraction

[0103] X-ray diffraction tests were performed on the CsPbBr3 quantum dot samples prepared in Example 1 and Comparative Example 1, and the results are as follows: Figure 2 As shown, it can be observed that the sample peak positions of the perovskite CsPbBr3 quantum dots involved in the present invention correspond one-to-one with the standard PDF card, and the phase purity is good.

[0104] 3. Photoabsorption and luminescence

[0105] The photoabsorption (Abs) and luminescence (PL) of the perovskite quantum dots prepared in Examples 1-8, 10-19 and Comparative Example 1 were tested, and spectral data were collected using a fluorescence spectrometer to obtain the photoabsorption and luminescence of different samples, as shown in FIG. Figure 3-6 and Figure 8-13 As shown. Figure 3 , proving that the CsPbBr3 quantum dots synthesized in the present invention have a lower overlapping area (S1 / (S1+S2)) of the photoabsorption and luminescence spectra than the quantum dots synthesized by the traditional method, proving that their reabsorption is lower and more conducive to X-ray imaging applications. Figure 4 , proving that the present invention can achieve different luminescence from blue to red by changing the type of hydrohalic acid. Figure 5-6 , proving that the present invention can adjust the polar solvents with different polarities used in the synthesis to achieve size control of CsPbBr3 quantum dots, thereby producing luminescence of different colors. Figure 3 and Figure 8-10 , proving that the use of different amounts of non-polar solvents is effective in regulating the polarity of the synthetic medium, and that the half-peak width of the photoluminescence peak obtained using 3 ml of n-hexane in Example 1 is the narrowest. Figure 3 and Figure 11-13 This proves that there are many options for acid in the preparation of the precursor cation solution, but the half-peak width of the photoluminescence peak obtained by using octanoic acid in Example 1 is the narrowest.

[0106] 4. Reaction temperature comparison

[0107] By comparing the colors of the crude CsPbBr3 quantum dot solutions prepared in Example 1 and Example 9, Figure 7 It can be clearly observed that the room temperature synthesis color is yellowish, and the low temperature synthesis color is emerald green. The emerald green color indicates a smaller quantum dot size and higher luminescence efficiency.

[0108] 5. Comparison of reaction concentration increase

[0109] The CsPbBr3 quantum dots prepared by Comparative Examples 1-4. Fig.14From the solution color comparison, it can be seen that comparative example 1 emits green light, while comparative example 3 emits blue light when the concentration is increased by 5 times; comparative example 2 emits green light, while comparative example 4 does not emit light when the concentration is increased by 5 times. Therefore, simply increasing the concentration of reactants during the traditional method and synthesis to increase the yield will cause the color of CsPbBr3 quantum dots to shift, and in severe cases, it will also lead to the inability to effectively synthesize CsPbBr3 quantum dots.

[0110] 6. Irradiation

[0111] The CsPbBr3 quantum dots prepared in Example 1 and Comparative Example 1 were subjected to radiant luminescence (RL) testing, and spectral data were collected using a fluorescence spectrometer to obtain the radiant luminescence of different samples. The results are as follows: Fig.15 As shown, it is proved that the irradiated luminescence intensity of CsPbBr3 quantum dots synthesized by low temperature and normal pressure polar solvent in the method of the present invention is several times higher than that of quantum dots synthesized by traditional methods, which effectively meets the requirements of ultrafast X-ray imaging.

[0112] 7. Resolution test

[0113] The CsPbBr3 quantum dot solution prepared in large quantities in Example 1 is Fig.17 As shown in the figure, it shows that it can easily expand the production of large quantities of perovskite quantum dots. Fig.18 As shown, the present invention fully meets the demand for a large number of perovskite quantum dots required for spraying a large area of ​​X-ray scintillator film. The resolution test of the CsPbBr3 quantum dot scintillator film prepared in Example 1 and Comparative Example 1 is as follows: Fig.16 As shown, it can be seen that the CsPbBr3 quantum dot scintillator film prepared by the present invention has a higher spatial resolution than the scintillator film prepared by the traditional method, and can reach a high spatial resolution of 10.0lp / mm on the resolution line pair card. Fig.19 The actual imaging effect diagram shows that the imaging quality of the scintillator film prepared by spraying is clear and meets the actual needs.

[0114] 8. Full-color display of CsPbX3 (X=Cl\Br\I) perovskite quantum dots

[0115] The CsPbI3, CsPbBr3, and CsPbCl3 perovskite quantum dot solutions synthesized in Examples 1, 2, and 3 were excited by ultraviolet light. Fig. 20 It can be seen that it emits bright red, green and blue light, which illustrates the universality of the present invention for the full-color luminescence of perovskite.

[0116] The above-mentioned implementation cases are only preferred implementation cases in the present invention, but the implementation methods of the present invention are not limited to the above-mentioned implementation cases. For example, various forms of combinations of the schemes in the embodiments, any other changes, modifications, substitutions, and combinations made without departing from the spirit and principles of the present invention should be equivalent replacement methods and are within the protection scope of the present invention.

Claims

1. A method for synthesizing CsPbX3 perovskite quantum dots using a low temperature polar solvent, characterized in that: The following steps are involved: Step 1, adding a Cs source, a Pb source, and an organic acid into a polar solvent, stirring at room temperature until dissolved, to obtain a cationic precursor solution; Step 2, adding the X source and the ligand into a polar solvent and stirring at room temperature to obtain an anion precursor solution; Step 3, mixing the above two precursor solutions to prepare a crude quantum dot solution, wherein during the mixing process, the stirring speed is set to 600 rpm, the temperature is 0-5° C., and the reaction time is 1 minute; Step 4, purifying the crude quantum dot solution obtained in step 3, centrifuging and dispersing, and taking the supernatant by centrifugation to obtain a CsPbX3 perovskite quantum dot solution.

2. The method according to claim 1, characterized in that The polar solvent is any one of toluene, n-butanol, ethyl acetate, acetone, isopropanol, ethanol and methanol, preferably ethyl acetate, isopropanol and methanol, and more preferably methanol.

3. The method according to claim 1, characterized in that The organic acid is any one of formic acid, acetic acid, octanoic acid, 2-ethyldecanoic acid and oleic acid, preferably octanoic acid.

4. The method according to claim 1, characterized in that The X source is any one or two of HI, HBr, and HCl.

5. The method according to claim 1, characterized in that The ligand is oleylamine.

6. The method according to claim 1, characterized in that The molar ratio of Cs source, Pb source and X source is 1:1:6; the molar ratio of ligand and X source is 1:1; The molar ratio of organic acid to Cs source is 3:

1.

7. The method according to claim 1, characterized in that The cationic precursor solution also contains a certain amount of non-polar solvent, or the anionic precursor solution also contains a certain amount of non-polar solvent, or a certain amount of non-polar solvent needs to be added when the two precursor solutions are mixed, and the volume ratio of the non-polar solvent to the polar solvent is 1:

3.

8. The method according to claim 1, characterized in that The non-polar solvent is any one of n-hexane, n-octane and toluene.

9. The method according to claim 1, characterized in that The crude quantum dot solution was purified by adding three times the volume of ethyl acetate, the precipitate was obtained by centrifugation, and then n-hexane was added for dispersion, and the supernatant was obtained by centrifugation to obtain the CsPbX3 perovskite quantum dot solution.

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