Method for preparing blue-light CsPbBr3 nanosheet through room-temperature anti-solvent etching
CsPbBr3 nanosheets were prepared by room temperature anti-solvent etching method, which solved the defect problem of low-dimensional perovskite blue light materials, and achieved efficient and stable preparation of blue light nanosheets, suitable for electroluminescent diodes.
Patent Information
- Application Number
- CN202510425700.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-07
- Publication Date
- 2025-07-08
AI Technical Summary
The prior art can easily cause large defect state density when preparing low-dimensional perovskite blue light materials, and the introduction of new ligands or etchants will damage the photoelectric properties or lead to side reactions.
The room temperature anti-solvent etching method is used to prepare CsPbBr3 nanosheets by controlling the temperature and solvent selection, avoiding the introduction of new ligands and etchants, and achieving structural transformation from quantum dots to nanosheets.
CsPbBr3 blue light nanosheets were prepared with uniform size, good dispersion and good crystallinity. The emission wavelength was 461nm, the half-maximum width was 12nm, the fluorescence quantum yield reached 85%, the stability in air and the spectrum was controllable.
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Figure CN120271038A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of perovskite nano-luminescent material preparation, and specifically refers to a method for preparing blue-light CsPbBr3 nanosheets by room-temperature antisolvent etching. Background Art
[0002] Due to their excellent optoelectronic properties, perovskite materials show great potential in the field of light-emitting displays, which promotes the development and application of the display field. Among them, small-size and low-dimensional perovskite blue-light materials with adjustable sizes have attracted extensive attention from researchers due to their high PLQY and exciton binding energy. However, the smaller size brings a larger specific surface area and higher surface energy, making low-dimensional materials prone to have a large defect density, which leads to their secondary growth and destroys the original morphology and optoelectronic properties. To passivate defects, researchers mainly passivate defects by introducing new ligands and etching surface defects with etchants. New ligands are likely to reduce the performance of optoelectronic devices, while etchants may cause new defects. At the same time, etchant residues may also cause side reactions to form unwanted by-products.
[0003] Therefore, a method for preparing low-dimensional perovskite blue-light nanocrystals with simple operation, excellent stability, and good optoelectronic properties has become an urgent problem to be solved. Summary of the Invention
[0004] The technical problem to be solved by the present invention is the large defect state density that is easily caused during the preparation of low-dimensional perovskite blue-light materials. To passivate defects, new ligands and etchants are mainly introduced to etch defects. However, the large introduction of new ligands will damage the conductivity of optoelectronic devices, and etchants will lead to the generation of by-products and new defects. The nucleation and growth of perovskite nanocrystal materials usually occur in a short time, and it is difficult to control the size of nanocrystals.
[0005] To solve the above technical problems, the technical solution provided by the present invention is: a method for preparing blue-light CsPbBr3 nanosheets by room-temperature antisolvent etching. The method for preparing blue-light CsPbBr3 nanosheets by room-temperature etching is as follows:
[0006] Step 1: Prepare a precursor solution. The raw materials of the precursor solution include lead bromide, cesium bromide, oleylamine, and DMF. Place the above raw materials in a glass bottle according to the ratio and heat and stir at room temperature until dissolved.
[0007] Step 2: Prepare a CsPbBr3 crude solution. The raw materials of the CsPbBr3 crude solution include the precursor solution and an antisolvent. Place the glass bottle of the precursor solution in a heating stirrer, heat and stir, and then add the antisolvent to obtain a CsPbBr3 quantum dot crude solution.
[0008] Step 3: Place the crude CsPbBr3 quantum dot solution obtained from the reaction in a small beaker;
[0009] Step 4: Place the small beaker in an open reactor, heat it, and evacuate to obtain a precipitate;
[0010] Step 5: Dissolve the precipitate in an organic solvent, perform centrifugation to obtain a well-dispersed CsPbBr3 nanosheet solution.
[0011] Further, in Step 1, the molar ratio of raw materials is lead bromide: cesium bromide: oleylamine: DMF = 1:1:1.9:325.
[0012] Further, in Step 2, the volume ratio of the precursor solution to the antisolvent is: precursor: antisolvent = 1:1.25.
[0013] Further, in Step 2, the antisolvent is one of anhydrous ethanol, acetone, toluene, and isopropanol; the temperature for injecting the antisolvent is 40 - 70 °C, and the reaction time is 2 min. The temperature for injecting the antisolvent is 65 °C.
[0014] Further, in Step 4, the heating temperature is 50 - 60 °C, and the heating time is 2 - 14 min. Preferably, it is 60 °C.
[0015] Further, the organic solvent in Step 5 is n - hexane.
[0016] The advantages of the present invention compared with the prior art are as follows: After the rapid nucleation and growth of CsPbBr3 nanocrystals are completed, in an air environment, under the temperature condition of 50 - 60 °C, the structural transformation from quantum dots to nanosheets is completed. The operation is simple, the spectrum is controllable, and continuous tuning from green light to blue light is achieved;
[0017] During the synthesis process of CsPbBr3 nanosheets in the present invention, no new organic ligands are introduced, which is beneficial to the application of light - emitting diodes;
[0018] During the synthesis process of CsPbBr3 nanosheets in the present invention, no new etching agents are introduced, which is beneficial to the stability of the nanosheets;
[0019] The method of the present invention can prepare CsPbBr3 blue - light nanosheets with uniform size, good dispersion, and good crystallinity. For the prepared blue - light nanosheets, the emission wavelength is 461 nm, the full width at half - maximum is 12 nm, the fluorescence quantum yield reaches 85%, and they have excellent stability. After being stored in an air environment for one month, their fluorescence intensity hardly decays. Description of the Drawings
[0020] Figure 1It is the absorption spectrum, fluorescence spectrum and fluorescence physical map of CsPbBr3 nanocrystals at different times under the cooling condition of Example 1 of the present invention.
[0021] Figure 2 It is the curve of the emission peak and fluorescence intensity of CsPbBr3 nanowires obtained in Example 1 changing with time.
[0022] Figure 3 It is the X-ray diffraction pattern (XRD) of CsPbBr3 nanowires obtained in Example 1.
[0023] Figure 4 It is the transmission electron microscope (TEM) of CsPbBr3 nanowires obtained in Example 1.
[0024] Figure 5 It is the fluorescence spectrum of Example 2, Example 3 and Example 4. Detailed implementation mode
[0025] The following further details a method for preparing blue-light CsPbBr3 nanosheets at room temperature according to the present invention with reference to the accompanying drawings.
[0026] Combined with the attached Figures 1 - 5 , the present invention is introduced in detail.
[0027] A method for preparing blue-light CsPbBr3 nanosheets at room temperature, the method for preparing blue-light CsPbBr3 nanosheets at room temperature is as follows:
[0028] Step 1: The raw materials for preparing the precursor solution include lead bromide, cesium bromide, oleylamine, and DMF. Place the above raw materials in a glass bottle according to the ratio and heat and stir at room temperature until dissolved;
[0029] Step 2: Prepare a CsPbBr3 crude solution. The raw materials for the CsPbBr3 crude solution include the precursor solution and an antisolvent. Place the glass bottle of the precursor solution in a heating stirrer, heat and stir, and then add the antisolvent to obtain a CsPbBr3 quantum dot crude solution;
[0030] Step 3: Place the obtained CsPbBr3 quantum dot crude solution in a small beaker;
[0031] Step 4: Place the small beaker in an open reactor, heat and evacuate to obtain a first precipitate;
[0032] Step 5: Dissolve the first precipitate in an organic solvent and perform a first centrifugation operation to obtain a CsPbBr3 nanosheet solution with good dispersibility.
[0033] In Step 1, the molar ratio of the raw materials is lead bromide: cesium bromide: oleylamine: DMF = 1:1:1.9:325.
[0034] In Step 2, the volume ratio of the precursor solution to the antisolvent is: precursor: antisolvent = 1:1.25.
[0035] In Step 2, the temperature for heating and stirring is 40 - 70 °C, and the reaction time is 2 min.
[0036] In Step 3, the amount of the CsPbBr3 quantum dot solution placed in the small beaker is 2 ml.
[0037] In Step 4, the heating temperature is 50 - 60 °C, and the reaction time is 2 - 14 min.
[0038] In Step 5, the organic solvent is n - hexane.
[0039] The specific implementation process of a method for preparing blue - light CsPbBr3 nanosheets at room temperature according to the present invention is as follows:
[0040] Example 1:
[0041] This example provides a method for preparing blue - light CsPbBr3 nanosheets at room temperature. The antisolvent used is absolute ethanol, and it specifically includes the following steps:
[0042] Step 1: Place lead bromide, cesium bromide, oleylamine, and DMF in a glass bottle in a molar ratio of 1:1:1.9:325, heat until dissolved, and prepare a precursor solution.
[0043] Step 2: Heat the glass bottle containing the precursor solution to 40 - 70 °C at room temperature, inject absolute ethanol solution according to the volume ratio of precursor to antisolvent of 1:1.25, and react for 2 min to obtain a crude CsPbBr3 quantum dot solution.
[0044] Step 3: Place the 2 ml solution obtained in Step 2 in a small beaker to obtain a suspension.
[0045] Step 4: Place the small beaker containing the suspension prepared in Step 3 in an open reactor, heat it at 50 - 60 °C and evacuate, react for 2 - 14 min to obtain a precipitate.
[0046] Step 5: Dissolve the precipitate in n - hexane, and its PL spectrum is as Figure 1 , and the crystallinity characterization XRD is as Figure 3 .
[0047] Example 2:
[0048] This example provides a method for preparing blue - light CsPbBr3 nanosheets at room temperature. The antisolvent used is acetone, and it specifically includes the following steps:
[0049] Step 1: Place lead bromide, cesium bromide, oleylamine, and DMF in a glass bottle in a molar ratio of 1:1:1.9:325, heat to dissolve, and obtain a precursor solution;
[0050] Step 2: Heat the glass bottle containing the precursor solution from room temperature to 40 - 70 °C, inject an acetone solution according to a volume ratio of precursor to antisolvent of 1:1.25, and react for 2 min to obtain a crude CsPbBr3 quantum dot solution;
[0051] Step 3: Place 2 ml of the solution obtained in Step 2 in a small beaker to obtain a suspension;
[0052] Step 4: Place the small beaker containing the suspension prepared in Step 3 in an open reactor, heat at 50 - 60 °C and evacuate, and react for 2 - 14 min to obtain a precipitate;
[0053] Step 5: Dissolve the precipitate in n - hexane, and its PL spectrum is as Figure 5 .
[0054] Example 3:
[0055] This example provides a method for preparing blue - light CsPbBr3 nanosheets at room temperature. The antisolvent used is toluene, and the specific steps are as follows:
[0056] Step 1: Place lead bromide, cesium bromide, oleylamine, and DMF in a glass bottle in a molar ratio of 1:1:1.9:325, heat to dissolve, and obtain a precursor solution;
[0057] Step 2: Heat the glass bottle containing the precursor solution from room temperature to 40 - 70 °C, inject a toluene solution according to a volume ratio of precursor to antisolvent of 1:1.25, and react for 2 min to obtain a crude CsPbBr3 quantum dot solution;
[0058] Step 3: Place 2 ml of the solution obtained in Step 2 in a small beaker to obtain a suspension;
[0059] Step 4: Place the small beaker containing the suspension prepared in Step 3 in an open reactor, heat at 50 - 60 °C and evacuate, and react for 2 - 14 min to obtain a precipitate;
[0060] Step 5: Dissolve the precipitate in n - hexane, and its PL spectrum is as Figure 5 .
[0061] Example 4:
[0062] This example provides a method for preparing blue - light CsPbBr3 nanosheets at room temperature. The antisolvent used is isopropanol, and the specific steps are as follows:
[0063] Step 1: Place lead bromide, cesium bromide, oleylamine, and DMF in a glass bottle in a molar ratio of 1:1:1.9:325, and heat to dissolve to obtain a precursor solution;
[0064] Step 2: Heat the glass bottle containing the precursor solution from room temperature to 40 - 70 °C, and inject an isopropanol solution in a volume ratio of the precursor to the antisolvent of 1:1.25 and react for 2 min to obtain a crude CsPbBr3 quantum dot solution;
[0065] Step 3: Place 2 ml of the solution obtained in Step 2 in a small beaker to obtain a suspension;
[0066] Step 4: Place the small beaker containing the suspension prepared in Step 3 in an open reactor, heat at 50 - 60 °C and evacuate, and react for 2 - 14 min to obtain a precipitate;
[0067] Step 5: Dissolve the precipitate in n - hexane, and its PL spectrum is as Figure 5 .
[0068] Comparative Example 1:
[0069] Some studies have used TAA as an etchant to etch aged CsPbBr3 quantum dots. Using TAA etching achieved the removal of surface defects of aged quantum dots, and a blue shift from 513 nm to 505 nm was achieved. However, by using TAA, only surface defects were removed and the size of the quantum dots could not be controllably adjusted, and a controllable transition from green light to blue light could not be achieved. At the same time, the etching of quantum dots by TAA was in a continuous state, and a corresponding solvent needed to be added to suspend the reaction and centrifuged for removal, which further increased the complexity of the process.
[0070] Comparative Example 2:
[0071] After the preparation of the crude green light quantum dot solution in the present invention, attempts were made to etch the green light quantum dots at temperatures below 50 °C and above 60 °C in the post - treatment stage. In this process, when the temperature was below 50 °C, the antisolvent could not volatilize in time, continuously etched the nanocrystals, resulting in the complete decomposition of the nanocrystals and the inability to prepare blue light nanosheets; when the temperature was above 60 °C, the antisolvent volatilized too fast, and the shallow - layer nanocrystals could not be peeled off from the surface of the green light nanocrystals, and the etching of the nanocrystals could not be achieved. The precipitate obtained showed green fluorescence emission after being dissolved in n - hexane.
[0072] Comparative Example 3:
[0073] The present invention uses a precursor solution heated below 40°C and above 70°C to prepare for injection of an anti-solvent to prepare a crude CsPbBr3 quantum dot solution. It is found that when the temperature is lower than 40°C, the anti-solvent cannot cause nanocrystals to precipitate from the original solvent to form nanocrystals, and thus the preparation of a crude quantum dot solution cannot be achieved; when the heating temperature is higher than 70°C, the solvent evaporates rapidly, and the solution quickly turns black after the anti-solvent is injected, and the preparation of a crude quantum dot solution cannot be achieved.
[0074] Based on the above implementation methods, the present invention selects lead bromide, cesium bromide, oleylamine, and DMF to prepare a precursor solution. The use of an anti-solvent as an etchant raw material is reasonable and has a simple operation method. CsPbBr3 nanosheets with good stability and high luminescence intensity can be prepared, and the prepared CsPbBr3 nanosheets can be ensured to have uniform size.
[0075] After the precursor is prepared, the present invention injects an anti-solvent in an air environment at a temperature of 40-70°C to prepare a crude solution of quantum dots; in the post-processing stage, the present invention continuously heats and evacuates at 50-60°C, which can not only promote the reaction, but also maintain good monodispersity, maintain stability while promoting the reaction, effectively improve the quality of the product, complete the structural transformation from quantum dots to nanosheets, and has simple operation, controllable spectrum, and realizes continuous adjustment from green light to blue light. The present invention realizes efficient and controllable synthesis of CsPbBr3 nanosheets by accurately matching the physical and chemical properties of precursors, ligands, solvents and anti-solvents, combined with optimized temperature conditions, and has the characteristics of both process simplicity and product high performance. The selection of raw materials and the setting of process conditions in the technical solution of the present invention have achieved unexpected technical effects.
[0076] In the synthesis process of the CsPbBr3 nanosheets, no new organic ligand is introduced, which is beneficial to the application of electroluminescent diodes.
[0077] In the synthesis process of the CsPbBr3 nanosheets, no new etching agent is introduced, which is beneficial to the stability of the nanosheets.
[0078] The method of the invention can prepare CsPbBr3 blue light nanosheets with uniform size, good dispersibility and good crystallinity. The prepared blue light nanosheets have an emission wavelength of 461nm, a half-peak width of 12nm, a fluorescence quantum yield of 85%, and excellent stability. After being stored in an air environment for one month, the fluorescence intensity thereof basically does not decay. The design of the invention is reasonable and worthy of being vigorously promoted.
[0079] The above description of the present invention and its embodiments is not restrictive. Generally speaking, if those of ordinary skill in the art are inspired by it and, without departing from the purpose of the present invention, design similar structural forms and embodiments to this technical solution without creative efforts, they shall fall within the protection scope of the present invention.
Claims
1. A method for preparing blue-light CsPbBr3 nanosheets by room-temperature anti-solvent etching, characterized in that: It includes the following steps: Step 1: Prepare a precursor solution. The raw materials of the precursor solution include lead bromide, cesium bromide, oleylamine, and DMF. Place the above raw materials in a glass bottle according to the ratio and stir at room temperature until dissolved; Step 2: Prepare a CsPbBr3 crude solution. The raw materials of the CsPbBr3 crude solution include the precursor solution and an antisolvent. Place the glass bottle of the precursor solution in a heating stirrer, heat and stir, and then add the antisolvent to obtain a CsPbBr3 quantum dot crude solution; Step 3: Take out the obtained CsPbBr3 quantum dot crude solution and place it in an open reactor, heat and evacuate to obtain a precipitate; Step 4: Dissolve the precipitate in an organic solvent, perform a centrifugation operation to obtain a CsPbBr3 nanosheet solution with good dispersibility.
2. The method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: In Step 1, the molar ratio of the raw materials is lead bromide: cesium bromide: oleylamine: DMF = 1:1:1.9:
325.
3. A method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: In Step 2, the volume ratio of the CsPbBr3 quantum dot crude solution to the antisolvent is 1:1.
25.
4. A method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: The antisolvent in Step 2 is one of anhydrous ethanol, acetone, toluene, and isopropanol.
5. A method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: The temperature for injecting the antisolvent in Step 2 is 40 - 70 °C.
6. A method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: The reaction temperature in Step 3 is 50 - 60 °C, and the reaction time is 2 - 14 min.
7. A method for preparing blue-light CsPbBr3 nanosheets at room temperature according to claim 1, characterized in that: The organic solvent in Step 4 is n-hexane.