CN112552908B - Perovskite quantum dot and preparation method and application thereof - Google Patents

Perovskite quantum dot and preparation method and application thereof Download PDF

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CN112552908B
CN112552908B CN202011431933.8A CN202011431933A CN112552908B CN 112552908 B CN112552908 B CN 112552908B CN 202011431933 A CN202011431933 A CN 202011431933A CN 112552908 B CN112552908 B CN 112552908B
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CN112552908A (en
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王储劼
郑策
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Wuxi Utmolight Technology Co Ltd
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Abstract

The invention discloses perovskite quantum dots, a preparation method and application thereof, wherein the method comprises the following steps: (1) Mixing the cation at the A position, lead organic acid, an alkyl acid ligand and a first alcohol polar solvent so as to obtain a first precursor liquid; (2) Mixing an alkylamine ligand, halogen acid and a second polar solvent, and stirring for reaction to obtain a second precursor solution; (3) And mixing the first precursor liquid with a stabilizer, and adding the second precursor liquid under the condition of stirring so as to obtain the perovskite quantum dot. The method is carried out at room temperature, the reaction process does not need heating and controlling the reaction atmosphere, the reaction steps are simple and convenient, the time consumption is short, the large-scale production is easy, meanwhile, toxic strong polar solvents and inert nonpolar solvents are not used, and the prepared quantum dot product has excellent luminous property and uniform microstructure.

Description

Perovskite quantum dot and preparation method and application thereof
Technical Field
The invention belongs to the technical field of perovskite quantum dots, and particularly relates to a perovskite quantum dot, a preparation method and application thereof.
Background
The perovskite quantum dot has excellent photoelectric performance, has the advantages of pure luminescent color, high luminescent quantum yield, high defect tolerance and the like, and is a competitor for next-generation display and illumination technology. There are numerous methods for preparing perovskite quantum dots at present, which are mainly classified into a high-temperature hot injection method and a ligand-assisted precipitation method. High temperature hot injection processes typically have temperatures above 150 ℃ and even as high as 280 ℃. By high temperature and the presence of the ligand, part of the precursor is dissolved in a nonpolar solvent (typically 1-octadeceneode); then injecting the solution of the other part of the precursor into a reaction container at high temperature to form perovskite and separate out; the morphology and size of the nanocrystals are controlled by the ligand and reaction time. The method for synthesizing perovskite quantum dots at room temperature is mainly a ligand-assisted precipitation method, and the method generally comprises the steps of dissolving a precursor in a polar solvent (mostly DMF, DMSO and the like) to form a precursor solution, and then dripping the precursor solution into a rapidly stirred non (weak) polar solvent (usually toluene, normal hexane, dichloromethane and the like) to rapidly form supersaturation of the whole solution, so that perovskite nanocrystals are precipitated.
The disadvantages of the prior art are as follows:
1. the heat injection method is difficult to amplify production, and has high requirements on uniformity of temperature control, uniformity of injection reaction and energy consumption because the reaction is carried out under the protection of high temperature and inert gas. It is difficult to obtain high quality products exceeding gram grade by the hot injection method.
2. The existing room temperature ligand assisted precipitation method uses DMF and other polar solvents, and the solvents have high toxicity, high boiling point and difficult removal. In particular DMF, the use thereof is banned or restricted by some developed countries. And as the mutation of the solubility is used as the driving force for quantum dot generation in the room temperature method, the obtained quantum dots have uneven particle size and morphology distribution, generally have lower luminous quantum yield, wider luminous peak and poor repeatability.
3. In the process of preparing the quantum dot ink, a relatively complex cleaning step is required for removing the high-boiling inert solvent (octadecene) used in the hot injection method or a polar solvent such as DMF used in the room temperature ligand-assisted precipitation method, and a polar solvent (such as ethyl acetate) is usually introduced to promote the precipitation of the quantum dot from the crude solution, so that the stability of the quantum dot is further reduced.
4. Lead halides are often used as precursors in both methods, as a halogen source and a lead source; the a-site cations are typically applied to thermal implantation and ligand-assisted precipitation using cesium oleate and cesium halide. Since the proportion of cesium, lead and halogen is limited in both methods, the surface of the generated quantum dot often has halogen element vacancy defects or redundant metal residues, and the stability is reduced.
5. In order to ensure the quality of the quantum dot product, the two methods mostly need to use anhydrous solvents and precursors to react, or need to carry out operations such as rotary evaporation, water removal, vacuum drying and the like on the precursors, thereby increasing the cost.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent. Therefore, the invention aims to provide the perovskite quantum dot, the preparation method and the application thereof, wherein the method is carried out under the condition of room temperature, the reaction process does not need heating and controlling the reaction atmosphere, the reaction steps are simple and convenient, the time consumption is short, the large-scale production is easy, meanwhile, toxic strong polar solvents and inert nonpolar solvents are not used, and the prepared quantum dot product has excellent luminous property and uniform microstructure.
In one aspect of the invention, a method of preparing perovskite quantum dots is presented. According to an embodiment of the invention, the method comprises:
(1) Mixing the cation at the A position, lead organic acid, an alkyl acid ligand and a first alcohol polar solvent so as to obtain a first precursor liquid;
(2) Mixing an alkylamine ligand, halogen acid and a second polar solvent, and stirring for reaction to obtain a second precursor solution;
(3) And mixing the first precursor liquid with a stabilizer, and adding the second precursor liquid under the condition of stirring so as to obtain the perovskite quantum dot.
According to the method for preparing the perovskite quantum dots, which is disclosed by the embodiment of the invention, the method is carried out under the room temperature condition, the reaction process is not needed to be heated and the reaction atmosphere is not needed to be controlled, the laboratory environment is needed, and meanwhile, the method is insensitive to parameters such as injection time point, position, stirring speed and the like, is easy to amplify production, and the amplification is limited by the capacity of a container; the method has the advantages of simple reaction steps, short time consumption and no need of any dewatering or purifying operation of the precursor liquid; the method does not use toxic strong polar solvent and inert nonpolar solvent, avoids the induction of quantum dot phase change, is easy to purify, has low toxicity, is environment-friendly and is low in cost. In addition, the proportion of the A-site cation source, the lead source and the halogen source can be respectively and independently adjusted, so that the morphology and the luminescence peak of the product quantum dot can be finely regulated and controlled. On the premise of amplified production, the obtained quantum dot product has excellent luminescence property and uniform microstructure, has the same or better performance as the quantum dot prepared by using a hot injection method in the prior art, and has good tolerance to water and polar solvents.
Reaction mechanism of the above examples: mixing the first precursor solution with a stabilizer, adding the second precursor solution under the condition of stirring, carrying out chemical reaction on A-site cations, lead ions and halogen ions immediately, forming cores to generate perovskite, coating alkyl acid ligands and alkylamine ligands on the surface of the perovskite, and limiting overgrowth and coarsening of the perovskite, wherein the obtained product is the nano-sized perovskite quantum dot.
In addition, the method for preparing perovskite quantum dots according to the above embodiment of the present invention may further have the following additional technical features:
in some embodiments of the invention, the method further comprises: (4) Centrifuging to remove supernatant liquid so as to enrich the perovskite quantum dots in the stabilizer solution, centrifuging again, and removing sediment so as to obtain perovskite quantum dot ink dispersion liquid.
In some embodiments of the invention, in step (1), the cation at position A is selected from the group consisting of CsR 1 At least one of the organic acids cesium of COO, wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups.
In some embodiments of the invention, the cation at position A is selected from the group consisting of MARs of the formula 1 At least one of the organic acids methylamine of COO, wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups.
In some embodiments of the invention, the cation at position A is selected from the group consisting of FAR 1 At least one of the organic acid formamidines of COO wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups.
In some embodiments of the invention, the cation at the a-position is cesium acetate, methyl ammonium acetate, or formamidine acetate.
In some embodiments of the invention, in step (1), the lead organic acid is selected from the group consisting of those having the structural formula Pb (R) 2 COO) 2 At least one of the organic acid lead of (2), wherein R 2 Is C 1-23 Alkyl or C 1-23 Alkenyl groups.
In some embodiments of the invention, the lead organic acid is lead acetate trihydrate, lead oleate, or lead stearate.
In some embodiments of the invention, the alkyl acid ligand is selected from the group consisting of compounds having the structural formula R 3 At least one of the organic acids of COOH, wherein R 3 Is C 7-23 Alkyl or C 7-23 Alkenyl groups.
In some embodiments of the invention, the alkyl acid ligand is octanoic acid, oleic acid, or stearic acid.
In some embodiments of the invention, the first alcohol polar solvent has a boiling point of 70 degrees celsius to 120 degrees celsius.
In some embodiments of the invention, the first alcoholic polar solvent is selected from at least one of isopropanol, ethanol, n-propanol, and butanol.
In some embodiments of the invention, in step (2), the alkylamine ligand is selected from the group consisting of compounds of formula R 4 NH 2 At least one of alkylamines wherein R 4 Is C 8-24 Alkyl or C 8-24 Alkenyl groups.
In some embodiments of the invention, the alkylamine ligand is oleylamine, octylamine, or octadecylamine.
In some embodiments of the invention, the hydrohalic acid is selected from at least one of hydrogen chloride, hydrogen bromide, and hydrogen iodide.
In some embodiments of the invention, the second polar solvent has a boiling point of 70 degrees celsius to 120 degrees celsius.
In some embodiments of the invention, the second polar solvent is selected from at least one of isopropanol, ethanol, n-propanol, and butanol.
In some embodiments of the invention, in step (3), the stabilizer is selected from at least one of n-hexane, pentane, octane, toluene, and methylene chloride.
In some embodiments of the invention, the molar ratio of the lead organic acid to the cation at the A-position is 1 (0.95-1.05), preferably 1:1. Thus, the quantum dot with the cube morphology can be obtained.
In some embodiments of the invention, the molar ratio of the lead organic acid to the cation at the A-position is (3-4): 5. Thus, the reaction product is a two-dimensional nanoplatelet, and the luminescence peak position can be blue shifted.
In some embodiments of the invention, the molar ratio of the lead organic acid to the alkyl acid ligand is 1 (4-20), preferably 1:6.
In some embodiments of the invention, the concentration of the lead ion precursor in the first precursor solution is 0.01mmol/mL-0.1mmol/mL, preferably 0.05mmol/mL.
In some embodiments of the invention, the concentration of the cationic precursor in the A-position in the first precursor solution is from 0.01mmol/mL to 0.1mmol/mL, preferably 0.05mmol/mL.
In some embodiments of the invention, the volume ratio of the first alcohol polar solvent to the stabilizer is 3:1 to 1:3, preferably 2:1.
In some embodiments of the invention, the molar ratio of the alkyl acid ligand to the alkyl amine ligand is from 1:3 to 3:1, preferably 1:1.
In some embodiments of the invention, the molar ratio of the lead organic acid to the halogen acid is 1 (4-40), preferably 1:6.
In a second aspect of the invention, the invention provides a perovskite quantum dot. According to the embodiment of the invention, the perovskite quantum dot is prepared by adopting the method described in the embodiment. Therefore, the obtained quantum dot product has excellent luminescence property and uniform microstructure, has the performance equivalent to or better than that of the quantum dot prepared by a hot injection method in the prior art, and has good tolerance to water and polar solvents.
In a third aspect of the invention, the invention provides an electronic device prepared using perovskite quantum dots obtained by the method as described in the above examples or using perovskite quantum dots as described in the above examples as a production raw material. Therefore, the electronic device has excellent photoelectric performance, and further meets the requirements of consumers.
Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:
fig. 1 is a flow chart of a method of preparing perovskite quantum dots according to one embodiment of the invention.
Fig. 2 is a flow chart of a method of preparing perovskite quantum dots according to yet another embodiment of the invention.
FIG. 3 is CsPbBr prepared in example 1 3 A schematic of the luminescent quantum yield of quantum dots.
FIG. 4 is CsPbBr prepared in example 1 3 A schematic diagram of a transmission electron microscope photograph of the quantum dot, wherein a is low magnification, and b is high magnification.
FIG. 5 is FAPbBr prepared in example 4 3 PL spectrum of quantum dots.
FIG. 6 is FAPbI prepared in example 5 3 PL spectrum of quantum dots.
Detailed Description
Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present invention and should not be construed as limiting the invention.
In one aspect of the invention, a method of preparing perovskite quantum dots is presented. According to an embodiment of the present invention, referring to fig. 1, the method includes:
s100: mixing the A-site cation, organic acid lead, alkyl acid ligand and first alcohol polar solvent
In this step, the a-cation, the organic acid lead, the alkyl acid ligand, and the first alcohol polar solvent are mixed, and the alkyl acid ligand assists the a-cation precursor and the organic acid lead to be completely dissolved and exist in an ionic form so as to obtain a first precursor liquid.
The specific type of the A-cation is not particularly limited according to the embodiment of the present invention, and may be arbitrarily selected by those skilled in the art according to the actual circumstances, and according to one embodiment of the present invention, the A-cation is selected from the group consisting of CsR 1 At least one of the organic acids cesium of COO, wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups are preferably cesium acetate. According to still another embodiment of the present invention, the cation at the A-position is selected from the group consisting of MARs of the formula 1 At least one of the organic acids methylamine of COO, wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups, preferably methyl ammonium acetate. According to yet another embodiment of the present invention, the cation at the A-position is selected from the group consisting of FAR 1 At least one of the organic acid formamidines of COO wherein R 1 Is C 1-23 Alkyl or C 1-23 Alkenyl groups, preferably formamidine acetate.
According to the embodiment of the present invention, the specific type of the above-mentioned organic acid lead is not particularly limited, and may be arbitrarily selected by those skilled in the art according to the actual circumstances, and as a preferable embodiment, the organic acid lead is selected from those having the structural formula Pb (R 2 COO) 2 At least one of the organic acid lead of (2), wherein R 2 Is C 1-23 Alkyl or C 1-23 Alkenyl groups, more preferably lead acetate trihydrate, lead oleate or lead stearate.
The specific type of the above-mentioned alkyl acid ligand is not particularly limited according to the embodiment of the present invention, and may be arbitrarily selected by those skilled in the art according to the actual circumstances, and according to one embodiment of the present invention, the alkyl acid ligand is selected from the group consisting of the structural formula R 3 At least one of the organic acids cesium of COOH, wherein R 3 Is C 7-23 Alkyl or C 7-23 Alkenyl, as a preferred embodiment, the alkyl acid ligand is selected from octanoic acid, oleic acid or stearic acid.
According to the embodiment of the present invention, the specific type of the first alcohol polar solvent is not particularly limited, as long as the precursor can be dissolved without damaging the perovskite crystal structure, and the first alcohol polar solvent can be optionally selected according to the actual situation, and as a preferred scheme, the boiling point of the first alcohol polar solvent is 70-120 ℃. Therefore, all precursors, ligands and the like participating in the reaction can be effectively ionized, so that the reaction is quick, full and thorough, and the yield is high; meanwhile, the reaction product can be stored in a crude solution taking an alcohol solvent as a main body for a long time, and phase change and coarsening can not occur. Further, the first alcohol-based polar solvent is at least one selected from the group consisting of isopropyl alcohol, ethyl alcohol, n-propyl alcohol and butyl alcohol.
According to the embodiment of the invention, the molar ratio of the A-site cation to the lead is adjustable, so that the morphology of the reaction product and the wavelength of luminescence can be controlled, specifically, the lower the ratio of the A-site cation is, the more the product tends to be a two-dimensional nano-sheet, and the luminescence peak can be blue-shifted. Further, the molar ratio of the organic acid lead to the A-site cation is 1 (0.95-1.05), preferably 1:1, so that the quantum dot with cubic morphology can be obtained. Further, the molar ratio of the organic acid lead to the A-site cation is (3-4): 5, whereby the reaction product is a two-dimensional nanoplatelet and the luminescence peak site is blue shifted.
Further, the molar ratio of the lead organic acid to the alkyl acid ligand is 1 (4-20), preferably 1:6. Thereby, the a-site cations and lead precursor are sufficiently dissolved. The inventors found that if the content of the alkyl acid ligand is too low, the a-site cation and the lead precursor cannot be effectively dissolved; if the content of the alkyl acid ligand is too high, nano-sized quantum dots cannot be obtained, but bulk crystals are generated, and the luminescence performance is poor.
Further, the concentrations of the cationic precursor at the A-site and the lead organic acid precursor in the first precursor solution are respectively 0.01mmol/mL-0.1mmol/mL, preferably 0.05mmol/mL. The inventors found that if the two cation concentrations were too low, alcohol solvents and stabilizers were wasted, and if the two cation concentrations were too high, effective mixing of the reactants was affected, reducing product quality.
S200: mixing alkylamine ligand, halogen acid and second polar solvent, stirring to react
In this step, an alkylamine ligand, a halogen acid and a second polar solvent are mixed and stirred to react, and the alkylamine ligand and the halogen acid undergo a neutralization reaction to obtain an alkylhalide amine salt which is completely dissolved and exists in an ionic form, so as to obtain a second precursor solution.
The specific type of the above alkylamine is not particularly limited according to the embodiment of the present invention, and may be optionally selected by those skilled in the art according to the actual circumstances, and as a preferable embodiment, the alkylamine ligand is selected from those having the structural formula R 4 NH 2 At least one of alkylamines wherein R 4 Is C 8-24 Alkyl or C 8-24 Alkenyl groups. More preferably, the alkylamine ligand is oleylamine, octylamine, or octadecylamine.
The specific type of the above-mentioned halogen acid is not particularly limited according to the embodiment of the present invention, and may be arbitrarily selected by those skilled in the art according to the actual circumstances, and as a preferable scheme, the halogen acid is selected from at least one of hydrogen chloride, hydrogen bromide and hydrogen iodide.
According to the embodiment of the present invention, the specific type of the second polar solvent is not particularly limited, and a person skilled in the art may optionally select the second polar solvent according to practical situations, and as a preferred scheme, the boiling point of the second polar solvent is 70-120 ℃. Therefore, all precursors, ligands and the like participating in the reaction can be effectively ionized, so that the reaction is quick, full and thorough, and the yield is high; meanwhile, the reaction product can be stored in a crude solution taking an alcohol solvent as a main body for a long time, and phase change and coarsening can not occur. Further, the second polar solvent is at least one selected from isopropanol, ethanol, n-propanol and butanol.
Further, the molar ratio of the alkyl acid ligand to the alkyl amine ligand is 1:3 to 3:1, preferably 1:1, and if the molar ratio of the alkyl acid ligand to the alkyl amine ligand is outside the above range (below or above the above range), the reaction product is not nano-sized quantum dots but bulk crystals, and the light emitting property is poor.
According to the embodiment of the invention, in order to obtain the quantum dot with excellent luminescence performance (the luminescence quantum efficiency is more than 90 percent and the half-peak width is less than 25 nm), enough halogen is required to be provided in the reaction so as to avoid halogen vacancy defects on the surface of the product. Further, the molar ratio of the organic acid lead to the halogen acid is 1 (4-40), preferably 1:6, thereby providing sufficient halogen to avoid halogen vacancy defects on the product surface. The inventor finds that if the content of the halogen acid is too low, enough halogen cannot be provided, halogen vacancy defects can occur on the surface of a product, and the luminous performance is poor; if the halogen acid content is too high, the luminous properties of the product cannot be further improved, resulting in the waste of halogen acid.
Further, the purity of the alkylamine ligand is 80% -90%, and the purities of HCl, HBr and HI in the halogen acid are respectively 38%, 48% and 57% in sequence, namely the corresponding saturated aqueous solution.
S300: mixing the first precursor liquid with a stabilizer, and adding the second precursor liquid under the condition of stirring
In the step, the first precursor solution and a stabilizer are mixed, the second precursor solution is added under the condition of stirring, the A-site cations, lead ions and halogen ions are subjected to chemical reaction immediately, perovskite is formed by nucleation, an alkyl acid ligand and an alkylamine ligand are coated on the surface of the perovskite, overgrowth and coarsening of the perovskite are limited, and the obtained product is the nano-sized perovskite quantum dot.
The specific type of the above-mentioned stabilizer according to the embodiment of the present invention is not particularly limited, and may be arbitrarily selected by those skilled in the art according to the actual circumstances, and as a preferable embodiment, the stabilizer is selected from at least one of n-hexane, pentane, octane, toluene and methylene chloride.
Further, the volume ratio of the first alcohol polar solvent to the stabilizer is 3:1 to 1:3, preferably 2:1. Thus, quantum dots with excellent luminescence properties (luminescence quantum efficiency >90%, half-width <25 nm) can be obtained, and quantum dot loss during purification can be reduced. The inventor finds that if the proportion of the first alcohol polar solvent is too high, the reaction rate is too high, the obtained product has wider particle size distribution and lower luminous efficiency; if the proportion of the stabilizer is too high, the precursor cannot be effectively dissolved, the quality of the obtained product is poor, and all quantum dots cannot be reserved during centrifugal purification. Meanwhile, as the proportion of the first alcohol polar solvent and the stabilizer is regulated, no additional polar anti-solvent is needed to be added for cleaning in the subsequent purification treatment, and unreacted raw materials and coarsened products can be removed only by two simple centrifugation.
Further, referring to fig. 2, the method further includes:
s400: centrifugal separation
In the step, after the stirring reaction is completed, centrifuging to remove supernatant, dispersing the obtained perovskite quantum dot precipitate in a stabilizer solution, centrifuging again, and removing the precipitate to retain the solution to obtain the high-quality quantum dot ink.
The method for preparing perovskite quantum dots according to the embodiment of the invention has at least one of the following advantages:
1. the method is carried out at room temperature, the reaction process is carried out without heating and controlling the reaction atmosphere and the laboratory environment, thereby avoiding the use of high temperature and inert gas environment of a hot injection method and inert solvents with high boiling point.
2. The method has simple and convenient steps and short time consumption, and the precursor liquid does not need any dewatering or purifying operation. Meanwhile, the reaction is insensitive to parameters such as injection time point, position, stirring speed and the like, and the amplification is easy to realize and limited by the capacity of the container, so that the problems that the mass production cannot be amplified or the amplified products are nonuniform in a thermal injection method are solved.
3. On the premise of being capable of realizing amplified production, the obtained quantum dot product has excellent luminescence property and uniform microstructure, and has the same or better performance as the quantum dot prepared by the hot injection method in the literature.
4. The method does not use toxic strong polar solvent and inert nonpolar solvent, avoids the induction of quantum dot phase change, is easy to purify, has low toxicity, is environment-friendly and low in cost, and thereby avoids using toxic solvents such as DMF and the like in the room temperature synthesis method.
5. Because the proportion of the first alcohol solvent and the stabilizer is regulated, no additional polar anti-solvent is needed to be added for cleaning during purification treatment, and unreacted raw materials and coarsened products are removed only by simple twice centrifugation, so that the cleaning and purifying steps are simplified, the waste of the solvent and the anti-solvent is reduced, and the environment-friendly requirement is met.
6. The proportion of the A-site cation source, the lead source and the halogen source is respectively and independently adjustable, and the morphology and the luminescence peak of the product quantum dot can be finely regulated and controlled, so that the problems of precursor waste and limited product quality caused by unbalanced stoichiometric ratio of the precursor in a hot injection method and a room temperature synthesis method are solved.
7. The perovskite quantum dot product obtained by the reaction has good tolerance to water and polar solvents, and the reaction system is insensitive to water, although the reaction process uses hydrated lead acetate, aqueous halogen acid solution and the like, the quality of the obtained quantum dot product is excellent, and the repeatability of the reaction is high, so that the use of anhydrous solvents and precursors is avoided, and the environmental requirement of the reaction is reduced.
In a second aspect of the invention, the invention provides a perovskite quantum dot. According to the embodiment of the invention, the perovskite quantum dot is prepared by adopting the method described in the embodiment. Therefore, the obtained quantum dot product has excellent luminescence property and uniform microstructure, has the performance equivalent to or better than that of the quantum dot prepared by a hot injection method in the prior art, and has good tolerance to water and polar solvents.
In a third aspect of the invention, the invention provides an electronic device prepared using perovskite quantum dots obtained by the method as described in the above examples or using perovskite quantum dots as described in the above examples as a production raw material. Therefore, the electronic device has excellent photoelectric performance, and further meets the requirements of consumers.
In an embodiment of the present invention, the electronic device is a display device, a light emitting diode, a laser device, a photodetector device, or the like.
The following detailed description of embodiments of the invention is provided for the purpose of illustration only and is not to be construed as limiting the invention. In addition, all reagents employed in the examples below are commercially available or may be synthesized according to methods herein or known, and are readily available to those skilled in the art for reaction conditions not listed, if not explicitly stated.
Example 1
Green light CsPbBr 3 The preparation of the quantum dots comprises the following steps:
1. preparing cesium lead precursors: in a conical flask was placed 100ml of isopropanol, 1.92g (10 mmol) of cesium acetate, 3.79g (10 mmol) of lead acetate trihydrate, then 9.6ml of octanoic acid (60 mmol) were added, and stirring was carried out until the precursor salt was completely dissolved, to obtain cesium lead precursor liquid.
2. Preparation of bromine oleylamine: to 16ml of isopropyl alcohol, 19.8ml (60 mmol) of oleylamine was added, and under stirring, 6.9ml of 48% (60 mmol) aqueous hydrobromic acid was slowly added, the mixture was rapidly changed from colorless to pale yellow and a large amount of heat was evolved, and after the mixture was cooled to room temperature, a bromine oleylamine precursor was obtained.
3. 50ml of n-hexane stabilizer was added to the cesium lead precursor solution, and under rapid stirring (1000 rpm), the bromine oleylamine precursor solution was poured, and the mixed solution turned green immediately under room light, indicating the formation of quantum dots. The overall stoichiometric ratio of each element and ligand is Cs: pb: br, acid: amine = 1:1:6:6:6. after stirring for one minute the reaction was completed.
4. The reacted solution was centrifuged directly (rotational speed 8000rpm, time 5 minutes). After centrifugation, the supernatant was discarded, and the quantum dot pellet was dispersed in the remaining n-hexane (about 40 ml) and centrifuged again (rotation speed 3000rpm, time 5 minutes). After centrifugation, the precipitate is discarded to obtain CsPbBr 3 Aqueous quantum dot ink dispersion (concentration approximately 150 mg/ml).
CsPbBr prepared in this example 3 The luminous quantum yield of the quantum dots is shown in figure 3, and the luminous peak of the obtained cesium lead bromine ink is 513nm, the half-peak width is 22nm, and the quantum yield is more than 90% as can be seen from figure 3. CsPbBr prepared in this example 3 The transmission electron micrograph of the quantum dot is shown in fig. 4, where a is low magnification (4 tens of thousands magnification) and b is high magnification (25 tens of thousands magnification). From FIG. 4 (a), it can be seen that the quantum dots have uniform nano-square (Nanocube) morphologyFrom 4 (b), it can be seen that the quantum dot nano square size is about 10 nm.
Example 2
Red light (under ultraviolet light) CsPbI 3 Preparation of quantum dots:
all steps are the same as in example 1, and only hydrobromic acid is replaced by hydroiodic acid with the same mole, and CsPbI emitting red light can be obtained through reaction 3 Quantum dots.
Example 3
Blue light (under ultraviolet light) CsPbCl 3 Preparation of quantum dots:
all steps are the same as in example 1, and only hydrobromic acid is replaced by hydrochloric acid with the same mole, and CsPbCl emitting blue light can be obtained through reaction 3 Quantum dots.
Example 4
FAPbBr 3 Preparation of quantum dots:
all steps are the same as in example 1, cesium acetate is replaced by formamidine acetate with the same mole, and blue light (under ultraviolet light) FAPbBr with emission light of 442nm and half-width of 14nm as shown in figure 5 can be obtained through reaction 3 Quantum dots.
Example 5
FAPbI 3 Preparation of quantum dots:
all steps are the same as in example 1, only cesium acetate is replaced by the same mole of formamidine acetate, hydrobromic acid is replaced by hydroiodic acid with the same mole number, and the orange light FAPbI with the emission light at 582nm and the half-width of 35nm as shown in figure 6 can be obtained 3 Quantum dots.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.
While embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the invention, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the invention.

Claims (3)

1. A method of preparing perovskite quantum dots, comprising:
(1) Mixing the cation at the A position, lead organic acid, an alkyl acid ligand and a first alcohol polar solvent so as to obtain a first precursor liquid;
(2) Mixing an alkylamine ligand, halogen acid and a second polar solvent, and stirring for reaction to obtain a second precursor solution;
(3) Mixing the first precursor liquid with a stabilizer, and adding the second precursor liquid under the condition of stirring so as to obtain perovskite quantum dots;
the cation at the A position is cesium acetate or formamidine acetate;
the organic lead acid is lead acetate trihydrate, lead oleate or lead stearate;
the alkyl acid ligand is octanoic acid, oleic acid or stearic acid;
the alkylamine ligand is oleylamine, octylamine or octadecylamine;
the stabilizer is at least one selected from n-hexane, pentane, octane, toluene and dichloromethane
The first alcohol polar solvent is at least one selected from isopropanol, ethanol, n-propanol and butanol;
the second glycol polar solvent is at least one selected from isopropanol, ethanol, n-propanol and butanol;
the molar ratio of the organic acid lead to the A-site cation is 1 (0.95-1.05);
the molar ratio of the organic acid lead to the alkyl acid ligand is 1 (4-6);
the concentration of the lead ion precursor in the first precursor solution is 0.01mmol/mL-0.1mmol/mL;
the concentration of the cationic precursor at the A site in the first precursor solution is 0.01mmol/mL-0.1mmol/mL;
the volume ratio of the first alcohol polar solvent to the stabilizer is 3:1-1:3;
the molar ratio of the alkyl acid ligand to the alkylamine ligand is 1:3-3:1;
the molar ratio of the organic acid lead to the halogen acid is 1 (4-6).
2. The method as recited in claim 1, further comprising:
(4) And (3) centrifugally separating to obtain perovskite quantum dot ink aqueous dispersion.
3. The method according to claim 1 or 2, wherein the hydrohalic acid is selected from at least one of hydrogen chloride, hydrogen bromide and hydrogen iodide.
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