Method for preparing perovskite quantum dots by normal-temperature solution reaction method

Abstract

The invention relates to the technical field of perovskite quantum dots, in particular to a method for preparing perovskite quantum dots through a normal-temperature solution reaction method. The preparation method comprises the following steps: dissolving a first ligand and a cation precursor in a first solvent, and then diluting with a second solvent to prepare a cation-ligand solution; dissolving a second ligand and lead salt in a first solvent, and then diluting by using a second solvent to prepare a lead salt-ligand solution; and mixing the lead salt-ligand solution with a second solvent, adding the cation-ligand solution under the condition of violent stirring to obtain a reaction system, and then reacting under the condition of normal temperature to obtain the perovskite quantum dots. The perovskite quantum dots can be prepared through a solution reaction method under a normal temperature condition, harsh conditions of a hot injection method and use of a large amount of an anti-solvent of a ligand-assisted precipitation method are avoided, rapid cooling from a high temperature is not needed, the quantum dots can be synthesized without using the anti-solvent, and the preparation method is simple and convenient. The defect that large-scale and large-batch production of the perovskite quantum dots is difficult to realize by the existing synthesis method can be overcome.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite quantum dots, and in particular 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 effect, have unique physical properties such as tunable emission wavelength, high photoluminescence quantum yield (PLQY), high color purity and low operating threshold, which makes 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 use a large amount of antisolvents, which limits their application range and increases production costs. Therefore, developing a method for preparing high-quality perovskite quantum dots under mild conditions is a hot topic in current research.

[0003] At present, 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 the Cs source precursor solution into the precursor solution containing Pb source and Br source under high temperature conditions, and precisely control the size and shape of the quantum dots by adjusting the reaction time (usually 3 to 5 seconds). It is the most commonly used synthesis method. The room temperature ligand-assisted precipitation method is to dissolve Cs, Pb, Br in a certain proportion with the ligand in DMF or DMSO solution at room temperature to form a precursor solution, and then quickly inject the precursor solution into the antisolvent to make the quantum dots supersaturated and precipitate instantly, thereby crystallizing and growing. Compared with the hot injection method, this method has milder conditions. Although the hot injection method and ligand-assisted precipitation method have achieved certain development and are the mainstream synthesis methods, the hot injection method requires the temperature to be instantly reduced from a higher temperature to about 0°C to inhibit the continued growth of quantum dots, and 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 and the production cost. In addition, during the injection process, it will cause excessive local concentration, thereby 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 purpose 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 does not require rapid cooling from a high temperature and can synthesize quantum dots without the use of an antisolvent, which can overcome the defects of existing synthesis methods that are difficult to achieve large-scale and mass production of perovskite quantum dots.

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

[0006] One of the technical solutions of the present invention is to provide a method for preparing perovskite quantum dots by a room temperature solution reaction method, the steps comprising:

[0007] Dissolving a first ligand and a cationic precursor in a first solvent, and then diluting with a second solvent to prepare a cation-ligand solution;

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

[0009] 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 reacted at room temperature to obtain the perovskite quantum dots.

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

[0011] Furthermore, the cationic precursor includes one of cesium salt, methylamine salt and formamidine salt.

[0012] Preferably, the cesium salt is cesium carbonate; the methylamine salt is methylamine acetate; and 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 usage ratio of the cationic precursor, the first ligand and the first solvent is (4-48) mmol: (20-240) mL: (100-400) mL.

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

[0017] Further, 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 usage ratio of the lead salt, the second ligand and the first solvent is (10-50) mmol: (50-250) mmol: (200-450) mL.

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

[0021] Furthermore, 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 and chlorobenzene are commonly used anti-solvents, they are not used as anti-solvents in the technical solution of the present invention, but as dispersants for the precursors, so that the precursors are dispersed in the solvent and crystallize and nucleate and grow when they collide in the solvent.

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

[0024] Furthermore, the reaction time is 0.5 to 30 minutes.

[0025] In the present invention, a low concentration cation-ligand solution and a lead salt-ligand solution are first prepared, and the concentrations of the cation-ligand solution and the lead salt-ligand solution are controlled to control the reaction rate during the reaction, thereby regulating the quality of the perovskite quantum dots.

[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, and crystallization nucleation and growth are performed to obtain quantum dots. Compared with the hot injection method, this method performs crystallization nucleation and growth at room temperature, and compared with the ligand-assisted precipitation method, this method does not require the addition of additional antisolvents.

[0027] The second technical solution of the present invention is to 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 at room temperature (the cation precursor and the lead salt are both dispersed in a solvent, and the influence of diffusion is eliminated by mixing the same solvent, thereby achieving collision of the precursors and further nucleation growth), avoiding the harsh conditions of the hot injection method and the large-scale use of antisolvents in the ligand-assisted precipitation method.

[0030] The method for preparing perovskite quantum dots of the present invention has mild conditions, uses a small amount of antisolvent, can be effectively scaled up, and realizes large-scale mass production of perovskite quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

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

[0033] Figure 2 The transmission electron microscopy particle size distribution calculation results of the perovskite quantum dots prepared in Example 2. DETAILED DESCRIPTION

[0034] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0035] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0036] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may 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 associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0037] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0038] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0039] The raw materials and reagents used in the specific embodiments of the present invention are all commercially available products. The normal temperature in the following examples of the present invention 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 perovskite quantum dots are:

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

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

[0044] S3. Mix 20 mL of lead salt-ligand solution and 200 mL of toluene, add 20 mL of cation-ligand solution under vigorous stirring, react for 10 minutes, stop stirring, and obtain perovskite quantum dots.

[0045] Example 2

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

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

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

[0049] S3. Mix 20 mL of lead salt-ligand solution and 160 mL of toluene, add 20 mL of cation-ligand solution under vigorous stirring, react for 8 minutes, stop stirring, and obtain perovskite quantum dots.

[0050] Example 3

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

[0052] S1. At 150°C, 16 mmol of cesium carbonate was mixed with 50 mL of diisooctyl hypophosphorous acid and 400 mL of decane, and the mixture was stirred vigorously until the cesium carbonate was completely dissolved. After cooling to room temperature, 350 mL of chlorobenzene solution was added to dilute the mixture 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 vigorously until PbBr2 was completely dissolved. After cooling to room temperature, 1000 mL of chlorobenzene solution was added to dilute the mixture to prepare a 0.04 M lead salt-ligand solution.

[0054] S3. Mix 20 mL of lead salt-ligand solution and 500 mL of chlorobenzene, add 20 mL of cation-ligand solution under vigorous stirring, react for 20 minutes, stop stirring, and obtain perovskite quantum dots.

[0055] Example 4

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

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

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

[0059] S3. Mix 20 mL of lead salt-ligand solution and 400 mL of n-hexane, add 20 mL of cation-ligand solution under vigorous stirring, react for 15 minutes, stop stirring, and obtain perovskite quantum dots.

[0060] Example 5

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

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

[0063] S2. At 130°C, 30 mmol of lead bromide was mixed with 50 mmol of trioctyl phosphate and 450 mL of nonane, and stirred vigorously until PbBr2 was completely dissolved. After cooling to room temperature, 300 mL of chlorobenzene solution was added to dilute the mixture to prepare a 0.04 M lead salt-ligand solution.

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

[0065] Example 6

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

[0067] S1. At 60°C, 6 mmol of cesium carbonate was mixed with 20 mL of oleic acid and 300 mL of n-hexane, and stirred vigorously until the cesium carbonate was completely dissolved. After cooling to room temperature, 280 mL of toluene solution was added to dilute the mixture to prepare a 0.01 M cesium salt-ligand solution.

[0068] S2. At 65°C, 40 mmol of lead iodide was mixed with 200 mmol of triphenylphosphine oxide and 250 mL of n-hexane, and stirred vigorously until PbI2 was completely dissolved. After cooling to room temperature, 250 mL of toluene solution was added to dilute the mixture to prepare a 0.08 M lead salt-ligand solution.

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

[0070] Example 7

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

[0072] S1. At 145°C, 8 mmol of cesium carbonate was mixed with 30 mL of diisooctyl hypophosphorous acid and 400 mL of octadecene, and stirred vigorously until the cesium carbonate was completely dissolved. After cooling to room temperature, 370 mL of chlorobenzene solution was added to dilute the solution to prepare a 0.01 M cesium salt-ligand solution.

[0073] S2. At 150°C, 40 mmol of lead chloride, 200 mmol of tri-n-octylphosphine oxide and 300 mL of octadecene were mixed and stirred vigorously until PbCl2 was completely dissolved. After cooling to room temperature, 200 mL of chlorobenzene solution was added to dilute the mixture to prepare a 0.08 M lead salt-ligand solution.

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

[0075] Example 8

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

[0077] S1. At 120°C, 48 mmol of formamidine acetate was mixed with 60 mL of diisooctyl hypophosphorous acid, 60 mL of oleic acid and 100 mL of octane, and stirred vigorously until the formamidine acetate was completely dissolved. After cooling to room temperature, 380 mL of n-hexane solution was added to dilute the mixture to prepare a 0.08 M formamidine-ligand solution.

[0078] S2. At 120°C, 10 mmol of lead bromide was mixed with 50 mmol of tri-n-octylphosphine and 250 mL of octane, and stirred vigorously until PbBr2 was completely dissolved. After cooling to room temperature, 250 mL of n-hexane solution was added to dilute the mixture to prepare a 0.02 M lead salt-ligand solution.

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

[0080] Example 9

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

[0082] S1. At 60°C, 10 mmol of methylamine acetate was mixed with 120 mL of diisooctyl hypophosphorous acid, 120 mL of phenylethylamine and 380 mL of n-hexane, and stirred vigorously until the methylamine acetate was completely dissolved. After cooling to room temperature, 380 mL of chlorobenzene solution was added to dilute the mixture to prepare a 0.01 M methylamine-ligand solution.

[0083] S2. At 65°C, 16 mmol of lead bromide was mixed with 80 mmol of tri-n-octylphosphine oxide and 450 mL of n-hexane, and stirred vigorously until PbBr2 was completely dissolved. After cooling to room temperature, 350 mL of chlorobenzene solution was added to dilute the mixture to prepare a 0.02 M lead salt-ligand solution.

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

[0085] Example 10

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

[0087] S1. At 110°C, 12 mmol of formamidine acetate was mixed with 60 mL of diisooctyl hypophosphorous acid, 60 mL of oleic acid and 240 mL of octane, and stirred vigorously until the formamidine acetate was completely dissolved. After cooling to room temperature, 240 mL of n-hexane solution was added to dilute the mixture to prepare a 0.02 M formamidine-ligand solution.

[0088] S2. At 115°C, 10 mmol of lead bromide was mixed with 50 mmol of triphenylphosphine oxide and 300 mL of octane, and the mixture was stirred vigorously until PbBr2 was completely dissolved. After cooling to room temperature, 200 mL of n-hexane solution was added to dilute the mixture to prepare a 0.02 M lead salt-ligand solution.

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

[0090] Embodiment 11

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

[0092] S1. At 140°C, 10 mmol of methylamine acetate was mixed with 90 mL of diisooctylphosphite, 90 mL of oleic acid and 400 mL of octadecene, and stirred vigorously until the methylamine acetate was completely dissolved. After cooling to room temperature, 420 mL of toluene solution was added to dilute the mixture to prepare a 0.01 M methylamine-ligand solution.

[0093] S2. At 140°C, 12 mmol of lead iodide was mixed with 60 mmol of oleylamine and 280 mL of octadecene, and stirred vigorously until PbI2 was completely dissolved. After cooling to room temperature, 320 mL of toluene solution was added to dilute the mixture to prepare a 0.02 M lead salt-ligand solution.

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

[0095] Example 12

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

[0097] S1. At 130°C, 8 mmol of formamidine acetate was mixed with 80 mL of phenylethylamine, 80 mL of oleic acid and 240 mL of decane, and stirred vigorously until the methylamine acetate was completely dissolved. After cooling to room temperature, 400 mL of n-hexane solution was added to dilute the mixture 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 the mixture was stirred vigorously until PbCl2 was completely dissolved. After cooling to room temperature, 400 mL of n-hexane solution was added to dilute the mixture to prepare a 0.02 M lead salt-ligand solution.

[0099] S3. Mix 20 mL of lead salt-ligand solution and 300 mL of n-hexane, add 20 mL of cation-ligand solution under vigorous stirring, react for 3 minutes, stop stirring, and obtain perovskite quantum dots.

[0100] Example 13

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

[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 vigorously until the cesium carbonate was completely dissolved. After cooling to room temperature, 240 mL of toluene solution was added to dilute the mixture 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 the mixture was stirred vigorously until the PbBr2 was completely dissolved. After cooling to room temperature, 200 mL of toluene solution was added to dilute the mixture to prepare a 0.04 M lead salt-ligand solution.

[0104] S3. Add 20 mL of the lead salt-ligand solution to 20 mL of the cation-ligand solution under vigorous stirring, react for 0.5 min, then stop stirring to obtain perovskite quantum dots.

[0105] Comparative Example 1

[0106] The traditional hot injection method is used as the method for synthesizing perovskite quantum dots. The preparation process is 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 the cesium carbonate was completely dissolved to obtain a Cs precursor;

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

[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, and dried under vacuum at 120 °C for half an hour, and then heated to 150 °C under a nitrogen atmosphere until the lead bromide was completely dissolved to obtain a PbBr2 precursor;

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

[0111] Comparative Example 2

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

[0113] S1. At room temperature, 4 mmol of lead bromide and 4 mmol of cesium bromide were dissolved in 100 mL of DMSO, 10 mL of oleic acid and 5 mL of oleylamine were added, and the mixture was stirred vigorously to completely dissolve the lead bromide and cesium bromide to obtain a CsPbBr3 precursor solution;

[0114] S2. Take 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] Experimental Example 1 Detection of Photoluminescence Quantum Yield (PLQY) of Perovskite Quantum Dots

[0116] The photoluminescence quantum yield of the perovskite quantum dots prepared in Examples 1-12 and Comparative Examples 1-2 was tested, and the results are shown in Table 1.

[0117] Table 1

[0118]

[0119]

[0120] As can be seen from Table 1, Examples 1-13 of the present application can successfully prepare quantum dots by changing different ligands and different solvents. 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 embodiments of the present application can be synthesized by solution phase reaction at room temperature, and the average PLQY is not much different from that of the hot injection method, and the PLQY value can reach 95%.

[0121] Experimental Example 2 Transmission electron microscopy (TEM) and PL half-maximum width (FWHM) detection of perovskite quantum dots

[0122] The perovskite quantum dots prepared in Examples 1-12 and Comparative Examples 1-2 were subjected to transmission electron microscopy particle size distribution calculation and half-peak width test. The results are shown in Figures 1-2 and Table 2.

[0123] Figure 1 This is a transmission electron microscope image of the perovskite quantum dots prepared in Example 2; Figure 2 The transmission electron microscopy particle size distribution calculation results of the perovskite quantum dots prepared in Example 2.

[0124] Table 2

[0125]

[0126]

[0127] As shown in Table 2, Examples 1-13 of the present invention can successfully prepare quantum dots by changing different ligands and different solvents. Compared with the traditional ligand-assisted precipitation method (Comparative Example 2), the particle size statistically measured by TEM images is significantly reduced, and the half-peak width 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 half-peak width and a more uniform size distribution. The synthesis method can be synthesized through a solution phase reaction at room temperature without the need for rapid cooling from a high temperature, and has obvious advantages in synthesis and industrial scale-up.

[0128] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all 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 include: Dissolving a first ligand and a cationic precursor in a first solvent, and then diluting with a second solvent to prepare a cation-ligand solution; Dissolving the second ligand and the lead salt in the first solvent, and then diluting 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 stirring conditions to obtain a reaction system, and then reacted under room temperature conditions to obtain the perovskite quantum dots.

2. The method according to claim 1, characterized in that The first ligand comprises at least one of oleic acid, diisooctylphosphinate and phenylethylamine; and / or The cationic precursor comprises one of a cesium salt, a methylamine salt and a formamidine salt; and / or The second ligand comprises at least one of oleylamine, octylamine, tri-n-octylphosphine, tri-n-octylphosphine oxide, triphenylphosphine oxide and tributyl phosphate; and / or The lead salt includes at least one of lead iodide, lead bromide and lead chloride.

3. The method according to claim 1, characterized in that The first solvent comprises at least one of n-hexane, octane, nonane, decane and octadecene; and / or The second solvent includes at least one of n-hexane, toluene and chlorobenzene.

4. The method according to claim 1, characterized in that The usage ratio of the cationic precursor, the first ligand and the first solvent is (4-48) mmol: (20-240) mL: (100-400) mL.

5. The method according to claim 1, characterized in that The usage ratio of the lead salt, the second ligand and the first solvent is (10-50) mmol: (50-250) mmol: (200-450) mL.

6. The method according to claim 1, characterized in that The concentration of the cationic precursor in the cation-ligand solution is 0.01M to 0.16M; and / or The concentration of the lead salt in the lead salt-ligand solution is 0.02M to 0.08M.

7. The method according to claim 6, characterized in that 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.

8. The method according to claim 1, characterized in that The reaction time is 0.5 to 30 minutes.

9. Perovskite quantum dots prepared by the method according to any one of claims 1 to 8.

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