A method for preparing perovskite quantum dots by a room-temperature solution reaction method

Abstract

The present invention relates to the technical field of perovskite quantum dots and discloses a method for preparing perovskite quantum dots by a room-temperature solution reaction method. In the present invention, a first ligand and a cation precursor are dissolved in a first solvent and then diluted with a second solvent to prepare a cation-ligand solution; a second ligand and a lead salt are dissolved in the first solvent and then diluted with the second solvent to prepare a lead salt-ligand solution; after the lead salt-ligand solution is mixed with the second solvent, the cation-ligand solution is added under vigorous stirring to obtain a reaction system, and then the reaction is carried out at room temperature to obtain perovskite quantum dots. The perovskite quantum dots can be prepared by a solution reaction method at room temperature, avoiding the harsh conditions of the thermal injection method and the large amount of anti-solvent used in the ligand-assisted precipitation method. There is no need to rapidly cool down from a high temperature, and quantum dots can be synthesized without using an anti-solvent, which can overcome the defect that it is difficult to achieve large-scale and mass production of perovskite quantum dots by the existing synthesis methods.

Description

Technical Field

[0001] The present invention relates to the technical field of perovskite quantum dots, and particularly to a method for preparing perovskite quantum dots by a room-temperature solution reaction method. Background Art

[0002] Quantum dots (QDs), as nanoscale semiconductor particles with quantum confinement effects, have unique physical properties such as tunable emission wavelength, high photoluminescence quantum yield (PLQY), high color purity, and low working threshold, making them have great prospects in various applications such as optoelectronic devices, such as light-emitting diodes (LEDs), solar cells, lasers, and sensors. However, traditional perovskite quantum dot synthesis methods usually require high-temperature conditions or the use of a large amount of antisolvent, which limits their application scope and increases production costs. Therefore, developing a method for preparing high-quality perovskite quantum dots under mild conditions is a current research hotspot.

[0003] Currently, the synthesis methods of perovskite quantum dots mainly include hot injection method, room-temperature ligand-assisted precipitation method, etc. The hot injection method is to inject a Cs source precursor solution into a precursor solution containing a Pb source and a Br source under high-temperature conditions, and precisely control the size and shape of the quantum dots by regulating the reaction time (usually 3 - 5 s), which is the most commonly used synthesis method currently. The room-temperature ligand-assisted precipitation method is to dissolve Cs, Pb, and Br in a certain ratio with a ligand in a DMF or DMSO solution to form a precursor solution at room temperature, and then quickly inject the precursor solution into an antisolvent to make the quantum dots instantaneously supersaturated and precipitate, thereby crystallizing and growing. Compared with the hot injection method, this method has milder conditions. Although the hot injection method and the ligand-assisted precipitation method have achieved certain developments and are the current mainstream synthesis methods, since the hot injection method needs to rapidly cool from a relatively high temperature to about 0 °C to inhibit the continuous growth of quantum dots, the reaction conditions are relatively harsh; the ligand-assisted precipitation method requires a volume ratio of the precursor solution to the antisolvent of more than 1:10 to ensure the precipitation of quantum dots, which greatly increases the amount of solvent used, increases production costs, and during the injection process, local concentration will be too high, thus affecting the quality of quantum dots. The existence of the above factors also limits the large-scale preparation of quantum dots. Summary of the Invention

[0004] The object of the present invention is to provide a method for preparing perovskite quantum dots by a room-temperature solution reaction method to solve the problems existing in the above-mentioned prior art. This method can synthesize quantum dots without rapidly cooling from high temperature and without using an antisolvent, and can overcome the defects that it is difficult to achieve large-scale and mass production of perovskite quantum dots by existing synthesis methods.

[0005] To achieve the above object, the present invention provides the following solution:

[0006] One of the technical solutions of the present invention: provides a method for preparing perovskite quantum dots by a room-temperature solution reaction method, and the steps include:

[0007] Dissolve the first ligand and the cation precursor in the first solvent, and then dilute with the second solvent to prepare a cation-ligand solution;

[0008] Dissolve the second ligand and the lead salt in the first solvent, and then dilute with the second solvent to prepare a lead salt-ligand solution;

[0009] After mixing the lead salt-ligand solution with the second solvent, add the cation-ligand solution under vigorous stirring to obtain a reaction system, and then react at room temperature to obtain the perovskite quantum dots.

[0010] Furthermore, the first ligand includes at least one of oleic acid (OA), diisooctylphosphinic acid (DOPA), and phenethylamine (PEA).

[0011] Furthermore, the cation precursor includes one of cesium salts, methylamine salts, and formamidine salts.

[0012] Preferably, the cesium salt is cesium carbonate; the methylamine salt is methylamine acetate; the formamidine salt is formamidine acetate.

[0013] Furthermore, the first solvent includes at least one of n-hexane, octane, nonane, decane, and octadecene.

[0014] Furthermore, the second solvent includes at least one of n-hexane, toluene, and chlorobenzene.

[0015] Furthermore, the dosage ratio of the cation precursor, the first ligand, and the first solvent is (4-48) mmol: (20-240) mL: (100-400) mL.

[0016] Furthermore, the concentration of the cation precursor in the cation-ligand solution is 0.01M to 0.16M.

[0017] Furthermore, the second ligand includes at least one of oleylamine (OAm), octylamine, tri-n-octylphosphine (TOP), tri-n-octylphosphine oxide (TOPO), triphenylphosphine oxide (TPPO), and tributyl phosphate (TBP).

[0018] Furthermore, the lead salt includes at least one of lead iodide (PbI2), lead bromide (PbBr2), and lead chloride (PbCl2).

[0019] Furthermore, the dosage ratio of the lead salt, the second ligand, and the first solvent is (10-50) mmol: (50-250) mmol: (200-450) mL.

[0020] Further, the concentration of the lead salt in the lead salt-ligand solution is 0.02 M to 0.08 M.

[0021] Further, the volume ratio of the lead salt-ligand solution, the second solvent, and the cation-ligand solution in the reaction system is 20:(0 - 500):20.

[0022] It should be noted that in the traditional ligand-assisted precipitation method for preparing perovskite quantum dots, although n-hexane, toluene, chlorobenzene, etc. are commonly used anti-solvents, in the technical solution of the present invention, they are not used as anti-solvents, but as dispersants for the precursors, so that the precursors are dispersed in the solvent and crystallize and nucleate during collision in the solvent.

[0023] In the reaction system, the molar ratio of the cation in the cation precursor to the lead ion in the lead salt is 4:1 to 1:4.

[0024] Further, the reaction time is 0.5 to 30 min.

[0025] In the present invention, a low-concentration cation-ligand solution and a lead salt-ligand solution are first prepared. By controlling the concentrations of the cation-ligand solution and the lead salt-ligand solution, the reaction rate during the reaction is controlled, and thus the quality of the perovskite quantum dots is regulated.

[0026] In the present invention, after the cation-ligand solution and the lead salt-ligand solution are mixed, the cation precursor and the lead salt collide with each other, and then react to crystallize and nucleate to grow quantum dots. Compared with the thermal injection method, this method crystallizes and nucleates at room temperature. Compared with the ligand-assisted precipitation method, this method does not require additional anti-solvents.

[0027] The second technical solution of the present invention: Provide a perovskite quantum dot prepared by the above method.

[0028] The present invention discloses the following technical effects:

[0029] The present invention can prepare perovskite quantum dots by a solution reaction method under room temperature conditions (the cation precursor and the lead salt are both dispersed in the solvent, and the influence brought by diffusion is eliminated through the mixing of the same solvent, thereby realizing the collision of the precursors, and then further nucleation and growth), avoiding the harsh conditions of the thermal injection method and the large amount of anti-solvents used in the ligand-assisted precipitation method.

[0030] The method for preparing perovskite quantum dots in the present invention has mild conditions, less anti-solvent consumption, can be effectively scaled up, and realizes the large-scale production of perovskite quantum dots. Description of the Drawings

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0032] Figure 1 It is the transmission electron microscope image of the perovskite quantum dots prepared in Example 2;

[0033] Figure 2 It is the calculation result of the particle size distribution of the transmission electron microscope of the perovskite quantum dots prepared in Example 2. Detailed implementation manners

[0034] Now, various exemplary implementation manners of the present invention will be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, characteristics, and implementation schemes of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing specific implementation manners and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded from the range.

[0036] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0037] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the present invention specification, which are obvious to those skilled in the art. Other implementation manners obtained from the present invention specification are also obvious to those skilled in the art. The present invention specification and embodiments are only exemplary.

[0038] Regarding the use of "comprising", "including", "having", "containing", etc. in this article, they are all open-ended terms, meaning including but not limited to.

[0039] In the specific implementation of the present invention, the raw materials and reagents used are all commercially available products. In the following examples of the present invention, the normal temperature refers to 20 - 30 °C; the vigorous stirring refers to the rotation speed being maintained at 200 - 1000 rpm.

[0040] Example 1

[0041] The preparation steps of the perovskite quantum dots are as follows:

[0042] S1. At 100 °C, 48 mmol of cesium carbonate is mixed with 80 mL of oleic acid and 280 mL of octane, and vigorously stirred until the cesium carbonate is completely dissolved. After cooling to room temperature, 240 mL of toluene solution is added for dilution to prepare a 0.08 M cesium salt - ligand solution;

[0043] S2. At 130 °C, 20 mmol of PbBr2 is mixed with 100 mmol of oleylamine and 300 mL of octane, and vigorously stirred until PbBr2 is completely dissolved. After cooling to room temperature, 200 mL of toluene solution is added for dilution to prepare a 0.04 M lead salt - ligand solution;

[0044] S3. 20 mL of the lead salt - ligand solution and 200 mL of toluene are mixed. Under vigorous stirring, 20 mL of the cation - ligand solution is added. After reacting for 10 min, the stirring is stopped to obtain the perovskite quantum dots.

[0045] Example 2

[0046] The preparation steps of the perovskite quantum dots are as follows:

[0047] S1. At 130 °C, 24 mmol of cesium carbonate is mixed with 20 mL of phenethylamine and 310 mL of nonane, and vigorously stirred until the cesium carbonate is completely dissolved. After cooling to room temperature, 270 mL of toluene solution is added for dilution to prepare a 0.04 M cesium salt - ligand solution;

[0048] S2. At 125 °C, 20 mmol of lead bromide is mixed with 100 mmol of octylamine and 300 mL of nonane, and vigorously stirred until PbBr2 is completely dissolved. After cooling to room temperature, 200 mL of toluene solution is added for dilution to prepare a 0.04 M lead salt - ligand solution;

[0049] S3. 20 mL of the lead salt - ligand solution and 160 mL of toluene are mixed. Under vigorous stirring, 20 mL of the cation - ligand solution is added. After reacting for 8 min, the stirring is stopped to obtain the perovskite quantum dots.

[0050] Example 3

[0051] The preparation steps of the perovskite quantum dots are as follows:

[0052] S1. At 150 °C, 16 mmol of cesium carbonate was mixed with 50 mL of diisooctylphosphinic acid and 400 mL of decane, and stirred strongly until the cesium carbonate was completely dissolved. After cooling to room temperature, it was diluted with 350 mL of chlorobenzene solution to prepare a 0.02 M cesium salt-ligand solution;

[0053] S2. At 140 °C, 50 mmol of lead bromide was mixed with 250 mmol of trioctyl phosphate and 250 mL of decane, and stirred strongly until PbBr2 was completely dissolved. After cooling to room temperature, it was diluted with 1000 mL of chlorobenzene solution to prepare a 0.04 M lead salt-ligand solution;

[0054] S3. 20 mL of the lead salt-ligand solution was mixed with 500 mL of chlorobenzene, and 20 mL of the cation-ligand solution was added under vigorous stirring. After reacting for 20 min, the stirring was stopped to obtain perovskite quantum dots.

[0055] Example 4

[0056] The preparation steps of the perovskite quantum dots are as follows:

[0057] S1. At 120 °C, 4 mmol of cesium carbonate was mixed with 30 mL of diisooctylphosphinic acid and 100 mL of octane, and stirred strongly until the cesium carbonate was completely dissolved. After cooling to room temperature, it was diluted with 270 mL of n-hexane solution to prepare a 0.01 M cesium salt-ligand solution;

[0058] S2. At 130 °C, 30 mmol of lead bromide was mixed with 50 mmol of tri-n-octylphosphine oxide and 450 mL of octane, and stirred strongly until PbBr2 was completely dissolved. After cooling to room temperature, it was diluted with 300 mL of n-hexane solution to prepare a 0.04 M lead salt-ligand solution;

[0059] S3. 20 mL of the lead salt-ligand solution was mixed with 400 mL of n-hexane, and 20 mL of the cation-ligand solution was added under vigorous stirring. After reacting for 15 min, the stirring was stopped to obtain perovskite quantum dots.

[0060] Example 5

[0061] The preparation steps of the perovskite quantum dots are as follows:

[0062] S1. At 120 °C, 20 mmol of cesium carbonate was mixed with 25 mL of phenethylamine and 205 mL of nonane, and stirred strongly until the cesium carbonate was completely dissolved. After cooling to room temperature, it was diluted with 270 mL of chlorobenzene solution to prepare a 0.04 M cesium salt-ligand solution;

[0063] S2. At 130 °C, mix 30 mmol of lead bromide with 50 mmol of trioctyl phosphate and 450 mL of nonane, stir vigorously until PbBr2 is completely dissolved, and after cooling to room temperature, add 300 mL of chlorobenzene solution for dilution to prepare a 0.04 M lead salt-ligand solution;

[0064] S3. Mix 20 mL of the lead salt-ligand solution and 400 mL of chlorobenzene, add 20 mL of the cation-ligand solution under vigorous stirring, and after reacting for 15 min, stop stirring to obtain perovskite quantum dots.

[0065] Example 6

[0066] The preparation steps of the perovskite quantum dots are as follows:

[0067] S1. At 60 °C, mix 6 mmol of cesium carbonate with 20 mL of oleic acid and 300 mL of n-hexane, stir vigorously until cesium carbonate is completely dissolved, and after cooling to room temperature, add 280 mL of toluene solution for dilution to prepare a 0.01 M cesium salt-ligand solution;

[0068] S2. At 65 °C, mix 40 mmol of lead iodide with 200 mmol of triphenylphosphine oxide and 250 mL of n-hexane, stir vigorously until PbI2 is completely dissolved, and after cooling to room temperature, add 250 mL of toluene solution for dilution to prepare a 0.08 M lead salt-ligand solution;

[0069] S3. Mix 20 mL of the lead salt-ligand solution and 120 mL of toluene, add 20 mL of the cation-ligand solution under vigorous stirring, and after reacting for 10 min, stop stirring to obtain perovskite quantum dots.

[0070] Example 7

[0071] The preparation steps of the perovskite quantum dots are as follows:

[0072] S1. At 145 °C, mix 8 mmol of cesium carbonate with 30 mL of diisooctylphosphinic acid and 400 mL of octadecene, stir vigorously until cesium carbonate is completely dissolved, and after cooling to room temperature, add 370 mL of chlorobenzene solution for dilution to prepare a 0.01 M cesium salt-ligand solution;

[0073] S2. At 150 °C, mix 40 mmol of lead chloride with 200 mmol of tri-n-octylphosphine oxide and 300 mL of octadecene, stir vigorously until PbCl2 is completely dissolved, and after cooling to room temperature, add 200 mL of chlorobenzene solution for dilution to prepare a 0.08 M lead salt-ligand solution;

[0074] S3. Mix 20 mL of the lead salt-ligand solution and 160 mL of chlorobenzene, and add 20 mL of the cation-ligand solution under vigorous stirring. After reacting for 10 min, stop stirring to obtain the perovskite quantum dots.

[0075] Example 8

[0076] The preparation steps of the perovskite quantum dots are as follows:

[0077] S1. At 120 °C, mix 48 mmol of formamidinium acetate with 60 mL of diisooctylphosphinic acid, 60 mL of oleic acid, and 100 mL of octane, and stir vigorously until the formamidinium acetate is completely dissolved. After cooling to room temperature, add 380 mL of n-hexane solution for dilution to prepare a 0.08 M formamidinium-ligand solution;

[0078] S2. At 120 °C, mix 10 mmol of lead bromide with 50 mmol of trioctylphosphine and 250 mL of octane, and stir vigorously until PbBr2 is completely dissolved. After cooling to room temperature, add 250 mL of n-hexane solution for dilution to prepare a 0.02 M lead salt-ligand solution;

[0079] S3. Mix 20 mL of the lead salt-ligand solution and 120 mL of n-hexane, and add 20 mL of the cation-ligand solution under vigorous stirring. After reacting for 5 min, stop stirring to obtain the perovskite quantum dots.

[0080] Example 9

[0081] The preparation steps of the perovskite quantum dots are as follows:

[0082] S1. At 60 °C, mix 10 mmol of methylammonium acetate with 120 mL of diisooctylphosphinic acid, 120 mL of phenethylamine, and 380 mL of n-hexane, and stir vigorously until the methylammonium acetate is completely dissolved. After cooling to room temperature, add 380 mL of chlorobenzene solution for dilution to prepare a 0.01 M methylamine-ligand solution;

[0083] S2. At 65 °C, mix 16 mmol of lead bromide with 80 mmol of trioctylphosphine oxide and 450 mL of n-hexane, and stir vigorously until PbBr2 is completely dissolved. After cooling to room temperature, add 350 mL of chlorobenzene solution for dilution to prepare a 0.02 M lead salt-ligand solution;

[0084] S3. Mix 20 mL of the lead salt-ligand solution and 400 mL of chlorobenzene, and add 20 mL of the cation-ligand solution under vigorous stirring. After reacting for 4 min, stop stirring to obtain the perovskite quantum dots.

[0085] Example 10

[0086] The preparation steps of the perovskite quantum dots are as follows:

[0087] S1. At 110 °C, mix 12 mmol of formamidine acetate with 60 mL of diisooctylphosphinic acid, 60 mL of oleic acid, and 240 mL of octane, stir vigorously until the formamidine acetate is completely dissolved, and after cooling to room temperature, add 240 mL of n - hexane solution for dilution to prepare a 0.02 M formamidine - ligand solution;

[0088] S2. At 115 °C, mix 10 mmol of lead bromide with 50 mmol of triphenylphosphine oxide and 300 mL of octane, stir vigorously until PbBr₂ is completely dissolved, and after cooling to room temperature, add 200 mL of n - hexane solution for dilution to prepare a 0.02 M lead salt - ligand solution;

[0089] S3. Mix 20 mL of the lead salt - ligand solution and 180 mL of n - hexane, add 20 mL of the cation - ligand solution under vigorous stirring, stop stirring after reacting for 2 min to obtain perovskite quantum dots.

[0090] Example 11

[0091] The preparation steps of perovskite quantum dots are as follows:

[0092] S1. At 140 °C, mix 10 mmol of methylammonium acetate with 90 mL of diisooctylphosphinic acid, 90 mL of oleic acid, and 400 mL of octadecene, stir vigorously until the methylammonium acetate is completely dissolved, and after cooling to room temperature, add 420 mL of toluene solution for dilution to prepare a 0.01 M methylamine - ligand solution;

[0093] S2. At 140 °C, mix 12 mmol of lead iodide with 60 mmol of oleylamine and 280 mL of octadecene, stir vigorously until PbI₂ is completely dissolved, and after cooling to room temperature, add 320 mL of toluene solution for dilution to prepare a 0.02 M lead salt - ligand solution;

[0094] S3. Mix 20 mL of the lead salt - ligand solution and 300 mL of toluene, add 20 mL of the cation - ligand solution under vigorous stirring, stop stirring after reacting for 3 min to obtain perovskite quantum dots.

[0095] Example 12

[0096] The preparation steps of perovskite quantum dots are as follows:

[0097] S1. At 130 °C, mix 8 mmol of formamidine acetate with 80 mL of phenethylamine, 80 mL of oleic acid, and 240 mL of decane, stir vigorously until the methylamine acetate is completely dissolved, and after cooling to room temperature, add 400 mL of n - hexane solution for dilution to prepare a 0.01 M formamidine - ligand solution;

[0098] S2. At 120 °C, 12 mmol of lead chloride was mixed with 60 mmol of tri-n-octylphosphine and 200 mL of decane, and stirred strongly until PbCl2 was completely dissolved. After cooling to room temperature, 400 mL of n-hexane solution was added for dilution to prepare a 0.02 M lead salt-ligand solution;

[0099] S3. 20 mL of the lead salt-ligand solution was mixed with 300 mL of n-hexane. Under vigorous stirring, 20 mL of the cation-ligand solution was added. After reacting for 3 min, the stirring was stopped to obtain perovskite quantum dots.

[0100] Example 13

[0101] The preparation steps of the perovskite quantum dots are as follows:

[0102] S1. At 100 °C, 6 mmol of cesium carbonate was mixed with 80 mL of oleic acid and 280 mL of octane, and stirred strongly until cesium carbonate was completely dissolved. After cooling to room temperature, 240 mL of toluene solution was added for dilution to prepare a 0.01 M cesium salt-ligand solution;

[0103] S2. At 130 °C, 20 mmol of PbBr2 was mixed with 100 mmol of oleylamine and 300 mL of octane, and stirred strongly until PbBr2 was completely dissolved. After cooling to room temperature, 200 mL of toluene solution was added for dilution to prepare a 0.04 M lead salt-ligand solution;

[0104] S3. 20 mL of the lead salt-ligand solution was added to 20 mL of the cation-ligand solution under vigorous stirring. After reacting for 0.5 min, the stirring was stopped to obtain perovskite quantum dots.

[0105] Comparative Example 1

[0106] The traditional hot injection method was used as the method for synthesizing perovskite quantum dots. The preparation process was as follows:

[0107] S1. In a three-necked flask, 25 mmol of cesium carbonate was mixed with 25 mL of oleic acid and 400 mL of octadecene, dried at 120 °C for 1 hour, and then heated to 150 °C under a nitrogen atmosphere until cesium carbonate was completely dissolved to obtain a Cs precursor;

[0108] Among them, the Cs precursor must be preheated to above 100 °C to dissolve the precursor before use;

[0109] S2. In a three-necked flask, 1.88 mmol of lead bromide was mixed with 10 mL of oleylamine, 10 mL of oleic acid and 50 mL of octadecene, dried under vacuum at 120 °C for half an hour, and then heated to 150 °C under a nitrogen atmosphere until lead bromide was completely dissolved to obtain a PbBr2 precursor;

[0110] S3. While maintaining the PbBr2 precursor in step S2 at a high temperature (150 °C), preheat the Cs precursor obtained in step S1 to above 100 °C, then aspirate 4 mL and quickly inject it into the PbBr2 precursor solution. After 5 s, cool it with an ice-water bath to obtain perovskite quantum dots.

[0111] Comparative Example 2

[0112] Adopt the traditional ligand-assisted precipitation method as the method for synthesizing perovskite quantum dots. The preparation process is as follows:

[0113] S1. At room temperature, dissolve 4 mmol of lead bromide and 4 mmol of cesium bromide in 100 mL of DMSO, add 10 mL of oleic acid and 5 mL of oleylamine, and stir vigorously to completely dissolve lead bromide and cesium bromide to obtain a CsPbBr3 precursor solution;

[0114] S2. Aspirate 10 mL of the CsPbBr3 precursor solution obtained in step S1 and quickly inject it into 150 mL of toluene under vigorous stirring to obtain perovskite quantum dots.

[0115] Test Example 1 Detection of Photoluminescence Quantum Yield (PLQY) of Perovskite Quantum Dots

[0116] Perform photoluminescence quantum yield tests on the perovskite quantum dots prepared in Examples 1-12 and Comparative Examples 1-2. The results are shown in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] As can be seen from Table 1, in Examples 1-13 of the present application, by changing different ligands and different solvents, quantum dots can be successfully prepared. Compared with the traditional ligand-assisted precipitation method (Comparative Example 2), the PLQY is significantly improved. Compared with the hot injection method (Comparative Example 1), the synthesis method of the examples of the present application can be synthesized by a solution-phase reaction at room temperature, and the average value of PLQY is not much different from that of the hot injection method, and the PLQY value can reach 95%.

[0121] Test Example 2 Transmission Electron Microscope (TEM) and PL Full Width at Half Maximum (FWHM) Detection of Perovskite Quantum Dots

[0122] Perform transmission electron microscope particle size distribution calculation and full width at half maximum test on the perovskite quantum dots prepared in Examples 1-12 and Comparative Examples 1-2. The results are shown in Figures 1 - 2 and Table 2.

[0123] Figure 1 Figure for the transmission electron microscope of the perovskite quantum dots prepared in Example 2;Figure 2 Calculation results of the particle size distribution of the perovskite quantum dots prepared in Example 2 by transmission electron microscopy.

[0124] Table 2

[0125]

[0126]

[0127] As can be seen from Table 2, in Examples 1-13 of the present invention, quantum dots can be successfully prepared by changing different ligands and different solvents. Compared with the traditional ligand-assisted precipitation method (Comparative Example 2), the particle size statistically obtained from the TEM images is significantly reduced, and the full width at half maximum is significantly narrowed; compared with the hot injection method (Comparative Example 1), the perovskite quantum dots synthesized in the examples of the present application have a smaller full width at half maximum, a more uniform size distribution, and the synthesis method can be carried out by a solution-phase reaction at room temperature without rapid cooling from a high temperature, having obvious advantages in synthesis and industrial scale-up.

[0128] The above-described embodiments are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for preparing perovskite quantum dots by a room-temperature solution reaction method, characterized in that the steps Comprising: Dissolve the first ligand and the cation precursor in the first solvent, and then dilute with the second solvent to prepare a cation-ligand solution; Dissolve the second ligand and the lead salt in the first solvent, and then dilute with the second solvent to prepare a lead salt-ligand solution; After mixing the lead salt-ligand solution with the second solvent, add the cation-ligand solution under stirring conditions to obtain a reaction system, and then react under normal temperature conditions to obtain the perovskite quantum dots; The first ligand includes at least one of oleic acid, diisooctyl phosphite, and phenethylamine; The cation precursor includes one of cesium salt, methylamine salt, and formamidine salt; The second ligand includes at least one of oleylamine, octylamine, tri-n-octylphosphine, tri-n-octylphosphine oxide, triphenylphosphine oxide, and tributyl phosphate; The lead salt includes at least one of lead iodide, lead bromide, and lead chloride; The first solvent includes at least one of n-hexane, octane, nonane, decane, and octadecene; The second solvent includes at least one of n-hexane, toluene, and chlorobenzene; The dosage ratio of the cation precursor, the first ligand, and the first solvent is (4~48) mmol:(20~240) mL:(100~400) mL; The dosage ratio of the lead salt, the second ligand, and the first solvent is (10~50) mmol:(50~250) mmol:(200~450) mL; The concentration of the cation precursor in the cation-ligand solution is 0.01M~0.16M; The concentration of the lead salt in the lead salt-ligand solution is 0.02M~0.08M; The volume ratio of the lead salt-ligand solution, the second solvent, and the cation-ligand solution in the reaction system is 20:(0~500):

20.

2. The method according to claim 1, characterized in that The reaction time is 0.5~30 min.

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