Perovskite quantum dot and preparation method and application thereof
By coating perovskite quantum dots with CsPbX1xX2y shells and/or CsPbX23 shells, the problem of insufficient light stability of perovskite quantum dots was solved, achieving high fluorescence efficiency and light-induced water and oxygen stability, thus expanding their applications in fields such as light-emitting diodes.
Patent Information
- Application Number
- CN202511520289.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-23
- Publication Date
- 2026-03-10
AI Technical Summary
Perovskite quantum dots have shortcomings in light stability, which limits their application in fields such as light-emitting diodes.
By coating CsPbX13 quantum dots with CsPbX1xX2y shells and/or CsPbX23 shells, and treating them with zinc fatty acid and HX2 solution, the ion migration of internal X1 atoms is suppressed, and the stability is improved by using the outer shell as a sacrificial layer.
High fluorescence efficiency and light-induced water and oxygen stability of perovskite quantum dots were achieved, with high fluorescence quantum yield and narrow fluorescence half-peak width, significantly improving their stability under light.
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Abstract
Description
Technical Field
[0001] This disclosure relates to the field of perovskite quantum dot synthesis technology, and more specifically, to a perovskite quantum dot, its preparation method, and its applications. Background Technology
[0002] In recent years, perovskite quantum dots have attracted widespread attention in fields such as solar cells, quantum dot films, and light-emitting diodes due to their optical and physical properties, such as high photoelectric conversion efficiency and low fabrication cost. As a luminescent material, perovskite quantum dots, compared to traditional inorganic semiconductor quantum dots (such as CdSe and CdS), can achieve full color gamut coverage by adjusting the element ratios and types within them. However, despite this, perovskite quantum dots still have many shortcomings, such as thermal stability, water resistance, and high light intensity stability, which limit their applications.
[0003] In 2015, Maksym V. Kovalenko's research group pioneered the synthesis of novel all-inorganic perovskite quantum dot cesium lead halide compounds (CsPbX3, where X represents Cl, Br, I, or a mixture of halogens in specific proportions (e.g., Cl and Br, Br and I)), leading the development of inorganic perovskite quantum dot synthesis. They injected a cesium oleate solution into a mixed solution containing lead halide, oleic acid, and oleylamine at a specific temperature (140-200℃), reacted for 5 seconds, and then immediately cooled with ice water. From their method, it is clear that its thermal stability is extremely poor. To date, almost all methods for synthesizing inorganic perovskite quantum dots are similar.
[0004] Perovskite quantum dots are ionic semiconductor materials. Even the currently most researched green luminescent CsPbBr3 perovskite quantum dots exhibit poor resistance to water, oxygen, light, and high temperatures. Furthermore, conventional perovskite quantum dots are unstable in polar solvents and easily decompose. These problems limit the application of perovskites in emerging fields such as light-emitting diodes (LEDs). Summary of the Invention
[0005] The purpose of this disclosure is to provide a perovskite quantum dot, its preparation method, and its application, thereby solving the technical problem of how to improve the light stability of perovskite quantum dots.
[0006] To address the aforementioned technical problems, a first aspect of this application provides a method for preparing perovskite quantum dots, the method comprising: S1, reacting a halogen precursor, a lead precursor, a cesium precursor, and a non-coordinated solvent at a first temperature to obtain CsPbX-containing quantum dots. 1 3. Perovskite quantum dot product system, X 1 It is bromine or chlorine; S2, with the addition of zinc fatty acid and HX2 a mixed solution of Zn(X 2 and the halogen precursor, or adding a mixed solution of Zn(X 2 )2 and the fatty acid, or adding a mixed solution of Zn(X 2 )2, the fatty acid and the halogen precursor into the product system, and reacting for a certain time to obtain a product system of the perovskite quantum dots after the first treatment, wherein when X 1 is bromine, X 2 is iodine, and when X 1 is chlorine, X 2 is bromine.
[0007] Optionally, the lead precursor and the cesium precursor are both fatty acid salts, and the number of carbon atoms of the fatty acid salts is 8-22; preferably, the number of carbon atoms of the zinc fatty acid and the fatty acid is independently selected from 8-22.
[0008] Optionally, S1 comprises: mixing zinc halide, oleylamine and oleic acid to obtain a halogen precursor of a clear solution by reacting for a certain time at a second temperature; mixing lead oleate, cesium oleate and the non-coordinating solvent and placing in a container and keeping at the first temperature; adding the halogen precursor into the container and reacting for a certain time to obtain the product system containing CsPbX 1 3 perovskite quantum dots; preferably, the first temperature is 20-200 ℃, and the second temperature is 100-200 ℃.
[0009] Optionally, the reaction temperature in S2 is 20-200 ℃; preferably, the reaction time of S2 is 30s-5min; preferably, the adding mode in S2 is injection or dropwise addition.
[0010] Optionally, the preparation method further comprises: S3, separating and purifying the product system of the perovskite quantum dots after the first treatment to prepare a non-coordinating solvent dispersion of perovskite quantum dots; S4, adding a mixed solution of zinc fatty acid and HX 2 , or adding a mixed solution of Zn(X 2 )2 and the fatty acid to the dispersion to obtain a product system of the perovskite quantum dots after the second treatment.
[0011] Optionally, the ratio of the absorbance of the non-coordinating solvent dispersion of the perovskite quantum dots at the first exciton absorption peak to the amount of substance of the X 2 element used in S4 in millimoles is 1000:1 to 10000:1.
[0012] Optionally, the temperature of the second treatment in S4 is 20-50 °C, and preferably, the treatment time is 5s-5min.
[0013] Optionally, X in S2 2 The molar ratio of element X to the halogen in S1 is 1:1 to 1:40; when the halogen precursor is used in S2, the X in S2... 2 The molar ratio of the element to the sum of the amounts of the halogen in S1 and the halogen in the halogen precursor in S2 is 1:1 to 1:10.
[0014] Optionally, X used in S2 2 Elements and X used in S4 2 The molar ratio of the elements is 1:10-10:1.
[0015] Another aspect of this application provides a perovskite quantum dot, said perovskite quantum dot comprising CsPbX 1 3 Perovskite quantum dot cores, CsPbX 1 x X 2 y Shell and CsPbX 2 3 shells, of which X 1 It is bromine or chlorine, when X 1 When it is bromine, X 2 Then it is iodine, when X 1 When it is chlorine, X 2 Then it is bromine, x+y=3; when the absorbance of the solution containing the perovskite quantum dots at 450 nm is 4, the fluorescence efficiency of the solution is greater than or equal to 80%, and the fluorescence half-width is less than or equal to 20 nm.
[0016] Optionally, the CsPbX 1 The average particle size of the 3 perovskite quantum dot cores is 8-10 nm, and the CsPbX cores are... 1 x X 2 y Shell and CsPbX 2 The sum of the thicknesses of the three shells is 2-4 nm.
[0017] Optionally, the solution is subjected to 450 nm blue light with an illumination intensity of 20 mW / cm². 2 After 48 hours of irradiation, the relative fluorescence efficiency of the solution remained above 70%.
[0018] In another aspect, this application provides a quantum dot composition comprising perovskite quantum dots prepared by any of the above-described preparation methods, or comprising perovskite quantum dots as described in any of the above-described methods.
[0019] In another aspect of the present application, a quantum dot display device is provided, which comprises the perovskite quantum dots prepared by any of the above preparation methods, or comprises the perovskite quantum dots as described above.
[0020] By using the above technical solution, the CsPbX 1 3 quantum dots are coated with CsPbX 1 x X 2 y The shell (x+y=3) and / or the CsPbX 2 3 shell can effectively inhibit the ion migration of the inner X 1 atoms, and the outer CsPbX 1 X 2 3 shell layer and the CsPbX 2 3 shell layer can also act as a sacrificial layer, thereby achieving the stability of the perovskite quantum dots. BRIEF DESCRIPTION OF DRAWINGS
[0021] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present disclosure and are incorporated herein for illustrative purposes. The schematic embodiments of the present disclosure and their descriptions are used to explain the present disclosure, and do not constitute an improper limitation on the present disclosure. In the drawings:
[0022] Figure 1 The fluorescence spectrum of the perovskite quantum dots during the preparation process of Example 1.
[0023] Figure 2 The TEM (Transmission Electron Microscope) image of the perovskite quantum dots obtained before the coating of Example 1.
[0024] Figure 3 The TEM image of the perovskite quantum dots finally obtained in Example 1. DETAILED DESCRIPTION
[0025] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.
[0026] According to a first aspect of the present application, a preparation method of perovskite quantum dots is provided, which comprises: S1, reacting halogen precursors, lead precursors, cesium precursors and non-coordinating solvents at a first temperature to obtain a product system containing CsPbX 1 3 perovskite quantum dots, X 1 is bromine or chlorine; S2, adding a mixed solution of zinc fatty acid and HX 2 , or adding zinc fatty acid, HX2 A mixed solution with halogen precursors, or with the addition of Zn(X) 2 A mixed solution of Zn(X) and fatty acids, or with the addition of Zn(X) 2 2. A mixed solution of fatty acids and halogen precursors is added to the product system and reacted for a certain time to obtain a product system of perovskite quantum dots after the first treatment, wherein, when X 1 When it is bromine, X 2 Then it is iodine, when X 1 When it is chlorine, X 2 It is bromine. HX 2 It is hydrobromic acid or hydroiodic acid.
[0027] In CsPbX 1 CsPbX coated on 3 quantum dots 1 x X 2 y Shell (x+y=3) and / or coating CsPbX 2 3 shells, one side internal X 1 The ion migration of atoms can be effectively suppressed, external CsPbX 1 X 2 3 shells and CsPbX 2 The three-shell layer can also serve as a sacrificial layer, thereby achieving the stability of perovskite quantum dots.
[0028] In some embodiments, both the lead precursor and the cesium precursor are fatty acid salts, wherein the fatty acid salt has 8-22 carbon atoms. In some embodiments, the number of carbon atoms in the zinc fatty acid and the fatty acid is independently selected from 8-22.
[0029] In some embodiments, S1 includes: mixing zinc halide, oleylamine, and oleic acid, reacting at a second temperature for a certain time to obtain a clear solution of a halogen precursor; mixing lead oleate, cesium oleate, and a noncoordinate solvent and placing them in a container, maintaining them at a first temperature; adding the halogen precursor to the container, reacting for a certain time to obtain a solution containing CsPbX. 1 3. Perovskite quantum dot product system. In some embodiments, the first temperature is 20-200°C, or 150-200°C. In some embodiments, the second temperature is 100-200°C.
[0030] In some embodiments, the reaction temperature in S2 is 20-200°C or 150-200°C. In some embodiments, the reaction time in S2 is 30s-5min. In some embodiments, S2 is added by injection or dropwise.
[0031] In some embodiments, the preparation method further comprises: S3, separating and purifying the product system of the first treated perovskite quantum dots to prepare a non-coordinating solvent dispersion of perovskite quantum dots; S4, adding a mixed solution of zinc fatty acid and HX 2 or adding a mixed solution of Zn(X 2 )2 and fatty acid to the dispersion for treatment to obtain a product system of second treated perovskite quantum dots. S4 further coats a CsPbX 2 3 shell, thereby further improving the stability of the perovskite quantum dots. The product system of the second treated perovskite quantum dots can not need further separation and purification.
[0032] The separation and purification of S3 can refer to the prior art, such as adding a precipitant and centrifugal separation.
[0033] In some embodiments, the ratio of the absorbance of the non-coordinating solvent dispersion of perovskite quantum dots at 450 nm to the amount of substance of X 2 element in S4 is 1000:1 to 10000:1, or 1000:1 to 3000:1, 5000:1 to 7000:1, 8000:1 to 10000:1.
[0034] In some embodiments, the temperature of the second treatment in S4 is 20-50 ℃, and preferably, the treatment time is 5s-5min.
[0035] The CsPbX 1 3 perovskite quantum dots can refer to the prior art, and in some embodiments, in S1, the molar ratio among the halogen of the halogen precursor, the lead element of the lead precursor, and the cesium element of the cesium precursor is 3:2:1 to 7.5:2:1.
[0036] By adjusting the amount of X 2 element in S2 and S4, the fluorescence peak position of the final perovskite quantum dots can be adjusted. In some embodiments, the molar ratio of X 2 element in S2 to halogen in S1 is 1:1-1:40 or 1:3-1:10; when a halogen precursor is used in S2, the molar ratio of X 2 element in S2 to the sum of the amount of substance of halogen in S1 (from the halogen precursor) and the halogen precursor in S2 (i.e., the total amount of substance of halogen in the halogen precursors used in S1 and S2) is 1:1-1:10 or 1:3-1:5.
[0037] In some embodiments, the mixed solution of zinc fatty acid and HX 2 or the mixed solution of zinc fatty acid, HX 2 and halogen precursor in the mixed solution of zinc fatty acid and HX 2The molar ratio of the elements is 3:1-1:3, preferably 1:1, Zn(X) 2 A mixed solution of Zn(X) and fatty acids or Zn(X) 2 2. Fatty acids and X in a mixed solution of fatty acids and halogen precursors 2 The molar ratio of the elements is 3:1 to 1:3, preferably 1.25:1.
[0038] In some embodiments, X used in S2 2 Elements and X used in S4 2 The molar ratio of the elements is 1:10-10:1 or 1:1-4:1 or 1:8-1:3 or 5:1-8:1.
[0039] In some embodiments, X 1 Chlorine, X 2 The method for preparing perovskite quantum dots, using bromine as the base, further includes: S5, separating and purifying the perovskite quantum dot product system after the second treatment to prepare another non-coordinate solvent dispersion of perovskite quantum dots; S6, adding a mixed solution of zinc fatty acid and hydroiodic acid, or a mixed solution of zinc iodide and fatty acid, to the dispersion to obtain the perovskite quantum dot product system after the third treatment. S6 further coats the perovskite quantum dots with a CsPbI3 shell, thereby further improving the stability of the perovskite quantum dots.
[0040] According to a second aspect of this application, a perovskite quantum dot is provided, the perovskite quantum dot comprising CsPbX 1 3 Perovskite quantum dot cores, CsPbX 1 x X 2 y Shell and CsPbX 2 3 shells, of which X 1 It is bromine or chlorine, when X 1 When it is bromine, X 2 Then it is iodine, when X 1 When it is chlorine, X 2 Then it is bromine, x+y=3; when the absorbance of the solution containing perovskite quantum dots at 450nm is 4, the fluorescence efficiency of the solution is greater than or equal to 80%, and the fluorescence half-width is less than or equal to 20nm. Since CsPbX 1 x X 2 y Shell and CsPbX 2 With the protection of a three-shell structure, this perovskite quantum dot exhibits high fluorescence quantum yield, narrow fluorescence half-peak width, and excellent stability under light, water, and oxygen.
[0041] In some embodiments, the solvent of the perovskite quantum dot-containing solution is a non-coordinate solvent, such as n-octane, 1-octadecene, etc.
[0042] In some embodiments, when the absorbance of the perovskite quantum dot solution at 450 nm is 4, the fluorescence half-width is greater than or equal to 14 nm or 15 nm.
[0043] In some embodiments, CsPbX 1 The average particle size of the perovskite quantum dot cores is 8-10 nm, CsPbX 1 x X 2 y Shell and CsPbX 2 The combined thickness of the three shells is 2-4 nm. In some embodiments, the fluorescence peak of the perovskite quantum dots is located at 450-650 nm.
[0044] In some embodiments, the fluorescence peak position of the perovskite quantum dots is 520-540 nm.
[0045] In some embodiments, the core-shell structured perovskite quantum dots are CsPbBr3 / CsPbBr x1 I y1 / CsPbI3, x1+y1=3. In some embodiments, the core-shell structured perovskite quantum dots are CsPbCl3 / CsPbCl x1 Br y1 / CsPbBr3 / CsPbBr x2 I y2 / CsPbI3, x1+y1=3, x2+y2=3.
[0046] In some embodiments, the solution of perovskite quantum dots is subjected to 450 nm blue light with an illumination intensity of 20 mW / cm². 2 After 48 hours of irradiation, the relative fluorescence efficiency of the solution remained above 70%.
[0047] The perovskite quantum dots mentioned above can be prepared using the methods described above.
[0048] According to a third aspect of this application, a quantum dot composition is provided, comprising perovskite quantum dots prepared by any of the above-described preparation methods, or perovskite quantum dots comprising any of the above-described methods.
[0049] According to a fourth aspect of this application, a quantum dot display device is provided, comprising perovskite quantum dots prepared by any of the above-described preparation methods, or perovskite quantum dots comprising any of the above-described methods.
[0050] The implementation methods are described in more detail below with reference to specific embodiments. However, these are exemplary examples of the present disclosure, and the present disclosure is not limited thereto.
[0051] Preparation of 0.5 mmol / mL bromine precursor: Add 4.5 g zinc bromide, 50 mmol oleic acid, and 70 mmol oleylamine to a 100 mL three-necked flask, raise the temperature to 120 °C, and react for 30 minutes. The preparation of other halogen precursors or the use of different metal halides can be achieved simply by changing the amounts used.
[0052] Preparation of a 0.5 mmol / mL zinc iodide oleic acid solution: Add 3.19 g of zinc iodide, 50 mmol of oleic acid, and 24 mL of ODE to a 100 mL three-necked flask. Increase the temperature to 150 °C and react for 30 minutes. The preparation of other halogen precursors, or the preparation of halogen precursors using different metal halides, simply involves changing the amounts used.
[0053] Preparation of zinc oleate-hydroiodic acid solution with an iodine concentration of 0.5 mmol / mL: Take 10 mL of 0.25 mmol / mL zinc oleate-ODE solution, add 5 mmol of hydroiodic acid, mix well, and it is ready.
[0054] Take 3.19 g of zinc iodide, 50 mmol of oleic acid, and 24 mL of ODE in a 100 mL three-necked flask, raise the temperature to 120 °C, and react for 30 minutes. The preparation of other halogen precursors or the use of different metal halides to prepare halogen precursors simply requires changing the amounts used.
[0055] Example 1
[0056] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and raise the temperature to 160 °C. Inject 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Measure the PL spectrum of the sample before treatment. Inject a zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine and react for 1 minute. Stop the reaction. Cool down and measure the PL spectrum of the first-treatment sample. Pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, dissolve in 5 mL of n-octane, and measure the PL spectrum of the purified sample at the absorbance of approximately 400 at the first exciton absorption peak. Then add a zinc oleate-hydroiodic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute. Measure the PL spectrum of the second-treatment sample. For the PL spectrum changes during the preparation process in Example 1, please refer to [reference needed]. Figure 1 As can be seen, the peak wavelength of PL shifts redward before and after the first and second treatments, indicating that shell coating occurred during the process. See the TEM images of the perovskite quantum dots for details. Figure 2 and Figure 3 .
[0057] Example 2
[0058] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and raise the temperature to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc iodide oleic acid solution containing 0.4 mmol of iodine and react for 1 minute before stopping the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide oleic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute. No additional separation or purification is required. The above reaction product is used as the final sample for integrating sphere testing. Other examples are the same and will not be repeated.
[0059] Example 3
[0060] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 0.04 mmol of iodine and react for another minute to stop the reaction. Cool down, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add the zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine, mix well, and react for 1 minute.
[0061] Example 4
[0062] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL concentration and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 1.5 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine, mix well, and react for 1 minute.
[0063] Example 5
[0064] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3.2 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 0.04 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add the zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine, mix well, and react for 1 minute.
[0065] Example 6
[0066] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 200 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add the zinc oleate-hydroiodic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0067] Example 7
[0068] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE in a 100 mL three-necked flask and maintain the temperature at 20 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine and react for another minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add the zinc oleate-hydroiodic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0069] Example 8
[0070] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 200 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc octate-hydroiodic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add the zinc octate-hydroiodic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0071] Example 9
[0072] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 200 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc dodecanoate-hydroiodic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc dodecanoate-hydroiodic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0073] Example 10
[0074] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 200 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc oleate-hydroiodic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-oleic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0075] Example 11
[0076] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL concentration and react for 1 minute. Then add a zinc iodide-octanoic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-octanoic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0077] Example 12
[0078] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and raise the temperature to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a zinc iodide-icosanoic acid solution containing 0.4 mmol of iodine and react for 1 minute to stop the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-icosanoic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0079] Example 13
[0080] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 2 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Then add a mixture of zinc iodide-oleic acid solution containing 0.4 mmol iodine and 1 mL of the 0.5 mmol / mL bromine precursor and react for 1 minute before stopping the reaction. Cool down, pour the original solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-oleic acid solution containing 0.04 mmol iodine, mix well, and react for 1 minute.
[0081] 14 implemented
[0082] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared 0.5 mmol / mL chlorine precursor and react for 1 minute. Then add a zinc iodide-oleic acid solution containing 0.4 mmol of iodine and react for 1 minute before stopping the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-oleic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0083] Example 15
[0084] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared 0.5 mmol / mL chlorine precursor and react for 1 minute. Then add a zinc bromide-oleic acid solution containing 0.4 mmol of bromine and react for 1 minute before stopping the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc bromide-oleic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0085] Example 16
[0086] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and heat to 160 °C. Add 3 mL of the prepared 0.5 mmol / mL chlorine precursor and react for 1 minute. Then add a zinc bromide-oleic acid solution containing 0.4 mmol of bromine and react for 1 minute before stopping the reaction. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane. Then add a zinc iodide-oleic acid solution containing 0.04 mmol of iodine, mix well, and react for 1 minute.
[0087] Comparative Example
[0088] Take 0.8 mL of 0.5 mmol / mL lead oleate solution, 1 mL of 0.2 mmol / mL cesium oleate solution, and 10 mL of ODE into a 100 mL three-necked flask and raise the temperature to 160 °C. Add 3 mL of the prepared bromine precursor at 0.5 mmol / mL and react for 1 minute. Cool down, pour the stock solution into a 50 mL centrifuge tube, add 10 mL of toluene and 20 mL of ethyl acetate, centrifuge at 4000 rpm for 3 minutes, precipitate, remove the supernatant, and dissolve in 5 mL of n-octane.
[0089] Fluorescence emission peak, fluorescence half-width at half-maximum (FWHM), fluorescence quantum yield, and stability of quantum dots in solution (using n-octane as solvent, absorbance at 450 nm was 4) were investigated. Specifically, the fluorescence quantum yield of the quantum dot solutions in the above embodiments was tested. The fluorescence quantum yield was determined using a 450 nm blue LED as the light source. An integrating sphere was used to measure the spectrum of the blue light source and the spectrum transmitted through the quantum dot solution. The luminous efficiency of the quantum dots was calculated using the integrated area of the spectra. The fluorescence quantum yield was calculated as: (Quantum dot emission peak area / (Blue backlight peak area - Unabsorbed blue peak area after transmission through the quantum dot solution)) * 100%. The luminous intensity of the blue LED used in the blue light irradiation experiment of the quantum dot solution was 20 mW / cm². 2 The quantum dot solution (container: an open glass bottle) was placed approximately 3 cm away from the blue LED. The test results are shown in the table below.
[0090] Number Fluorescence peak position (nm) before treatment Fluorescence peak position (nm) after first treatment Fluorescence peak position (nm) after purification Fluorescence peak position (nm) after second treatment Fluorescence efficiency (%) Fluorescence half-peak width (nm) Fluorescence quantum yield (%) after 48 hours of blue light irradiation of quantum dot solution Example 1 512 533 522 531 85 18 78 Example 2 513 532 522 531 83 19 79 Example 3 513 520 515 529 83 18 79 Example 4 512 540 533 539 85 19 81 Example 5 514 525 519 532 83 18 78 Example 6 512 531 522 532 83 18 79 Example 7 509 528 518 526 81 18 78 Example 8 512 533 521 532 83 20 76 Example 9 512 529 520 531 81 18 79 Example 10 512 532 521 530 85 18 79 Example 11 512 532 522 531 83 19 78 Example 12 511 530 521 529 83 18 80 Example 13 505 527 520 531 85 18 81 Example 14 415 487 477 485 85 15 79 Example 15 415 457 443 460 83 16 75 Example 16 415 457 443 467 83 16 79 Comparative Example 512 / / / 73 23 43
[0091] As can be seen from the table above, both the fluorescence quantum yield and the fluorescence half-width are significantly improved, and the solution light stability is significantly enhanced.
[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A method for preparing perovskite quantum dots, comprising the steps of: preparing a solution of a perovskite precursor; and adding a solution of a ligand precursor to the solution of the perovskite precursor. The preparation method comprises: S1, reacting a halogen precursor, a lead precursor, a cesium precursor and a non-coordinating solvent at a first temperature to obtain a product system of perovskite quantum dots containing CsPbX 1 3, X 1 is bromine or chlorine; S2, adding a mixed solution of a fatty acid zinc and HX 2 , or adding a mixed solution of a fatty acid zinc, HX 2 and the halogen precursor, or adding a mixed solution of Zn(X 2 )2 and a fatty acid, or adding a mixed solution of Zn(X 2 )2, a fatty acid and a halogen precursor into the product system, and reacting for a certain time to obtain a product system of perovskite quantum dots after first treatment, wherein, when X 1 is bromine, X 2 is iodine, and when X 1 is chlorine, X 2 is bromine.
2. The method for preparing perovskite quantum dots according to claim 1, characterized in that, The lead precursor and the cesium precursor are both fatty acid salts, and the number of carbon atoms of the fatty acid salts is 8-22; preferably, the number of carbon atoms of the fatty acid zinc and the fatty acid is independently selected from 8-22.
3. The method for preparing perovskite quantum dots according to claim 1, characterized in that, The S1 comprises: mixing zinc halide, oleylamine and oleic acid to obtain a halogen precursor of a clear solution at a second temperature for a certain time; mixing lead oleate, cesium oleate and the non-coordinating solvent and placing in a container, and keeping at the first temperature; adding the halogen precursor in the container, and reacting for a certain time to obtain the CsPbX 1 3product system of perovskite quantum dots; preferably, the first temperature is 20-200°C, and the second temperature is 100-200°C.
4. The method for preparing perovskite quantum dots according to claim 1, characterized in that, The reaction temperature in S2 is 20-200℃; preferably, the reaction time of S2 is 30s-5min; preferably, the adding mode in S2 is injection or dropwise addition.
5. The method for preparing perovskite quantum dots according to claim 1, characterized in that, The preparation method further comprises: S3, separating and purifying the product system of the first treated perovskite quantum dots to prepare a non-coordinating solvent dispersion liquid of perovskite quantum dots; S4, adding a mixed solution of zinc fatty acid and HX 2 , or adding a mixed solution of Zn(X 2 )2 and fatty acid to the dispersion liquid for treatment to obtain a second treated product system of perovskite quantum dots; preferably, the ratio of the absorbance of the non-coordinating solvent dispersion liquid of perovskite quantum dots at the first exciton absorption peak to the amount of substance of the X 2 element used in S4 in millimoles is 1000:1 to 10000:
1. 6.The method of claim 5, wherein the perovskite quantum dots are prepared by the method of claim 1, and the perovskite quantum dots have a size of 1 nm to 10 nm. The temperature of the second treatment in S4 is 20-50℃, and preferably, the treatment time is 5s-5min.
7. The method for preparing perovskite quantum dots according to claim 1, characterized in that, X in said S2 2 the molar ratio of the element to the halogen in said S1 is 1 : 1 - 1 : 40; when said halogen precursor is used in S2, the molar ratio of the element to X in said S2 2 the molar ratio of the element to the sum of the amounts of substances of the halogen in said S1 and the halogen in the halogen precursor in S2 is 1 : 1 - 1 :
10.
8. The method for preparing perovskite quantum dots according to claim 1, characterized in that, X used in said S2 2 Element and X used in said S4 2 The molar ratio of the elements is 1:10-10:
1.
9. A perovskite quantum dot, characterized in that, The perovskite quantum dot includes CsPbX 1 3perovskite quantum dot core, CsPbX 1 x X 2 y shell and CsPbX 2 3shell, wherein X 1 is bromine or chlorine, when X 1 is bromine, X 2 is iodine, when X 1 is chlorine, X 2 is bromine, x+y=3; when the absorbance of a solution containing the perovskite quantum dot at 450 nm is 4, the fluorescence efficiency of the solution is greater than or equal to 80%, and the fluorescence half-peak width is less than or equal to 20 nm.
10. The perovskite quantum dot of claim 10, wherein, CsPbX 1 3The average particle size of the perovskite quantum dot core is 8-10 nm, and the CsPbX 1 x X 2 y shell and CsPbX 2 3The sum of the thicknesses of the shells is 2-4 nm; preferably, the solution is irradiated with 450 nm blue light and an illumination intensity of 20 mW / cm 2 The relative fluorescence efficiency of the solution remains above 70% when irradiated for 48 hours.
11. A quantum dot composition, characterized in that, The quantum dot composition comprises the perovskite quantum dots prepared by the preparation method of any one of claims 1 to 8, or comprises the perovskite quantum dots of any one of claims 9 to 10.
12. A quantum dot display device, characterized by comprising: The quantum dot display device comprises the perovskite quantum dots prepared by the preparation method of any one of claims 1 to 8, or comprises the perovskite quantum dots of any one of claims 9 to 10.