A p-aminobenzenesulfonic acid / zinc bromide synergistic passivated csPbBr3 nanosheet and a preparation method and application thereof

Abstract

The application discloses a kind of p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 Nanosheet and its preparation method and application, belong to perovskite luminescent material technical field.The method includes: cesium carbonate is dissolved in oleic acid, and the preparation of cesium oleate precursor solution;Lead bromide, oleic acid, oleylamine and p-aminobenzenesulfonic acid are dissolved in N,N-dimethylformamide, and cesium oleate precursor solution is added, and reaction precursor solution is prepared, is injected into toluene and is reacted, and p-aminobenzenesulfonic acid modified CsPbBr3 Nanosheet dispersion is prepared;After purification, zinc bromide post-processing solution is used to surface treatment nanosheet.The application introduces p-aminobenzenesulfonic acid in the growth process of nanosheet, and is combined with zinc bromide post-processing, realizes the synergistic passivation of the surface undercoordination lead ion and bromine vacancy defect of CsPbBr3 Nanosheet, and the obtained material has the characteristics of blue light emission, high photoluminescence quantum yield and environmental storage stability.

Description

Technical Field

[0001] This invention belongs to the field of perovskite luminescent materials technology, specifically relating to a p-aminobenzenesulfonic acid / zinc bromide synergistic passivation of CsPbBr3 nanosheets, its preparation method, and its application. Background Technology

[0002] Metal halide perovskite nanocrystals possess advantages such as narrow emission linewidth, tunable emission color, high photoluminescence quantum yield (PLQY), and convenient solution processing, making them promising candidates for applications in light-emitting diodes, displays, lighting, and photoelectric detection. Among these, all-inorganic CsPbBr3 perovskite nanosheets can modulate the intrinsic green light emission of CsPbBr3 to the blue light region through quantum confinement effects along the thickness direction, avoiding the halogen migration and phase separation problems common in Cl / Br mixed-halogen systems. Therefore, they represent an important class of materials for achieving high-purity blue light emission.

[0003] However, CsPbBr3 nanosheets have a large specific surface area, and their surface contains a large number of undercoordinated Pb. 2+ Sites, bromine vacancies, and surface defects caused by ligand desorption are all factors to consider. Oleic acid and oleylamine are commonly used as surface ligands in traditional preparation processes. These long-chain organic ligands primarily rely on dynamic weak binding to ionic perovskite surfaces, making them prone to desorption during purification, storage, UV irradiation, heating, or humidity conditions. Ligand desorption exposes uncoordinated Pb. 2+ The presence of halogen vacancies promotes the formation of halogen sites, leading to enhanced nonradiative recombination, reduced photoluminescence quantum yield, redshift of the emission peak, or the appearance of impurity peaks, ultimately resulting in decreased blue light emission stability. Therefore, a simple, mild modification method is needed to effectively control surface defects in CsPbBr3 nanosheets to meet their application requirements in blue optoelectronic devices. Summary of the Invention

[0004] The main objective of this invention is to provide a method for preparing CsPbBr3 nanosheets with synergistic passivation by p-aminobenzenesulfonic acid / zinc bromide. Using p-aminobenzenesulfonic acid as an in-situ surface modifier and zinc bromide as a post-treatment halogen replenishment and synergistic passivation agent, blue-emitting CsPbBr3 nanosheets are obtained. This method solves the problem that in the traditional preparation process of CsPbBr3 nanosheets, the long-chain organic ligands such as oleic acid / oleylamine have weak bonding with the perovskite surface and are prone to dynamic desorption, resulting in device performance degradation due to insufficient material stability and poor charge transport performance when used as a light-emitting layer or light-emitting conversion layer in light-emitting diodes.

[0005] Another objective of this invention is to provide a p-aminobenzenesulfonic acid / zinc bromide synergistic passivation method for CsPbBr3 nanosheets. This method involves introducing p-aminobenzenesulfonic acid during nanosheet growth and combining it with zinc bromide post-treatment to achieve synergistic passivation of undercoordinated lead ions and bromine vacancies on the surface of CsPbBr3 nanosheets. The resulting material exhibits blue light emission, high photoluminescence quantum yield, and environmental storage stability. This improves upon the problem of weak binding between traditional oleic acid / oleylamine ligands and the surface of CsPbBr3 nanosheets, which is prone to dynamic desorption, and reduces surface defects and bromine vacancies caused by ligand desorption.

[0006] Another object of the present invention is to provide the application of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation of CsPbBr3 nanosheets in optoelectronic functional devices.

[0007] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide, comprising the following steps:

[0009] S1: Cesium carbonate is dissolved in oleic acid, heated and stirred to dissolve, thus preparing a cesium oleate precursor solution;

[0010] S2: Lead bromide, oleic acid, oleylamine and p-aminobenzenesulfonic acid are dissolved in N,N-dimethylformamide, heated and stirred to dissolve, and a lead source precursor solution containing p-aminobenzenesulfonic acid is prepared.

[0011] S3: Add the cesium oleate precursor solution to the lead source precursor solution containing p-aminobenzenesulfonic acid, stir and mix to obtain the reaction precursor solution;

[0012] S4: The reaction precursor solution is injected into toluene to carry out the reaction, and a p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion is obtained.

[0013] S5: The p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion is centrifuged and redispersed to obtain a purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion.

[0014] S6: Add zinc bromide to a mixed solvent of n-hexane and oleylamine, heat and stir to obtain a zinc bromide post-treatment solution;

[0015] S7: Add the zinc bromide post-treatment solution to the purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion, stir the reaction and centrifuge, collect the supernatant to obtain p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets.

[0016] In this process, p-aminobenzenesulfonic acid participates in surface coordination modification during nanosheet growth, and zinc bromide performs halogen replenishment and surface defect passivation on the nanosheets during post-treatment. The two work synergistically to achieve defect suppression.

[0017] Preferably, the defect suppression includes suppressing ligand desorption, bromine vacancy formation, and nonradiative recombination induced by surface defects.

[0018] Preferably, in step S1, the solution is first heated and stirred at 120°C until it becomes clear, then the temperature is raised to 150°C and held for 30-60 minutes, and the holding time is 15 minutes.

[0019] Preferably, in step S2, the molar ratio of lead bromide to p-aminobenzenesulfonic acid is 1:1-5, more preferably 1:2.5. The stirring temperature is 40-50℃, and the stirring time is 10-15 min.

[0020] Preferably, in step S3, after adding the cesium oleate precursor solution to the lead source precursor solution containing p-aminobenzenesulfonic acid, the stirring time is 3-5 minutes.

[0021] Preferably, in step S4, after the reaction precursor solution is injected into toluene, the reaction time is 60 seconds.

[0022] Preferably, in step S5, ethyl acetate with a volume twice that of the p-aminobenzenesulfonic acid-modified CsPbBr3 nanosheet dispersion is added and centrifuged at a speed of 6000-10000 rpm for 5 min. The solvent used for redispersion is n-hexane.

[0023] Preferably, in step S6, the mixed solvent is composed of n-hexane and oleylamine, the heating temperature is 40-50°C, the stirring time is 60 min, and the concentration of zinc bromide in the zinc bromide post-treatment solution is 10-80 mmol / L, more preferably 25-40 mmol / L.

[0024] Preferably, in step S7, after adding the purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion to the zinc bromide posttreatment solution, the mixture is stirred in air for 3-5 min, centrifuged at 4000 rpm for 3 min, and the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets are stored in a refrigerator at 0-10℃.

[0025] In a second aspect, the present invention provides a p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheet, which is prepared by the method for preparing the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheet.

[0026] A third aspect of the present invention provides the application of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation of CsPbBr3 nanosheets in optoelectronic functional devices.

[0027] Preferably, the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets are used as luminescent materials or luminescent conversion layer materials for optoelectronic functional devices.

[0028] Preferably, the optoelectronic functional device includes a light-emitting diode, a display device, a solid-state lighting device, a photodetector, or a solar cell.

[0029] Compared with the prior art, the beneficial effects of the present invention are at least as follows:

[0030] (1) Traditional oleic acid and oleylamine mainly rely on the dynamic weak binding of carboxyl and amino groups to the perovskite surface. The ligands are prone to desorption, thereby exposing uncoordinated Pb. 2+ This invention introduces p-aminobenzenesulfonic acid, which possesses polar functional groups such as amino and sulfonic acid groups, to induce bromine vacancy formation. Compared with traditional oleic acid / oleylamine ligand modification methods, this invention provides stronger multi-site surface interactions. Furthermore, combined with the halogen replenishment and passivation effects of zinc bromide post-treatment, it can more effectively suppress ligand desorption, bromine vacancy formation, and non-radiative recombination induced by surface defects, thereby improving the luminescence efficiency and environmental stability of CsPbBr3 nanosheets.

[0031] (2) The present invention adopts the room temperature method, which can be carried out under air conditions. The reaction process is simple and the conditions are mild, and no high temperature inert gas is required.

[0032] (3) Improve luminescence efficiency. This invention effectively passivates the undercoordinated lead ions and bromine vacancy defects on the surface of CsPbBr3 nanosheets through the synergistic effect of in-situ modification with aminobenzenesulfonic acid and post-treatment with zinc bromide, thereby inhibiting defect-induced nonradiative recombination and improving the luminescence performance of the material.

[0033] (4) Maintaining high color purity blue light emission. The CsPbBr3 nanosheets prepared by this invention can maintain stable blue light emission and have a narrow emission half-width, indicating that its emission spectrum is concentrated and its color purity is high, making it suitable as a blue light emitting material for display and lighting devices.

[0034] (5) Improved air storage stability. The CsPbBr3 nanosheets prepared by this invention can maintain relatively stable blue light emission when stored in an air environment, reducing spectral changes and luminescence attenuation caused by ligand desorption, bromine vacancy formation, and nanosheet aggregation or growth. Attached Figure Description

[0035] Figure 1The UV absorption spectrum (dashed line) and fluorescence emission spectrum (solid line) of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets prepared in Example 1 and the original CsPbBr3 nanosheets prepared in Example 2 are shown. The inset is a physical image of the CsPbBr3 nanosheet material under 365nm UV irradiation.

[0036] Figure 2 The images show the PLQY plots of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets prepared in Example 1 and the original CsPbBr3 nanosheets prepared in Example 2.

[0037] Figure 3 The images show the fluorescence of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivated CsPbBr3 nanosheets prepared in Example 1 and the original CsPbBr3 nanosheets prepared in Example 2 after 30 days of storage under environmental conditions. Detailed Implementation

[0038] To more fully understand and demonstrate the technical solutions, objectives, and advantages of the present invention, the technical effects produced by the present invention will be further described in detail and completely below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. It should be noted that other embodiments obtained by those skilled in the art without departing from the concept of the present invention are all within the protection scope of the present invention.

[0039] Unless otherwise specified, all reagents and materials used in the following examples are commercially available.

[0040] Example 1: Preparation of CsPbBr3 nanosheets with synergistic passivation by p-aminobenzenesulfonic acid / zinc bromide

[0041] (1) Preparation of cesium oleate precursor solution: Weigh 325 mg Cs2CO3 and add it to 10 mL of oleic acid. Stir continuously at 120 °C until the solution is clear. Stirring time is 30-60 min. Then heat to 150 °C and keep warm for 15 min to obtain cesium oleate precursor solution for later use.

[0042] (2) Preparation of lead source precursor solution containing p-aminobenzenesulfonic acid: Weigh 0.0367g PbBr2 and add it to 2.5mL DMF. At the same time, add 200μL oleic acid, 100μL oleylamine and 43.3mg p-aminobenzenesulfonic acid. Stir at 40-50℃ for 10-15 min until a clear light yellow solution is formed.

[0043] (3) Preparation of reaction precursor solution: Add 50 μL of cesium oleate precursor solution obtained in step (1) to the lead source precursor solution obtained in step (2) and continue stirring for 3-5 min.

[0044] (4) Take 100 μL of the reaction precursor solution obtained in step (3), quickly inject it into 2 mL of toluene and stir for 60 s to obtain a blue light emitting p-aminobenzenesulfonic acid-CsPbBr3 nanosheet dispersion.

[0045] (5) Purification treatment: Add 2 volumes of ethyl acetate, centrifuge at 6000-10000 rpm for 5 min, discard the supernatant, and redisperse the obtained precipitate in 2 mL of n-hexane or toluene to obtain the purified p-aminobenzenesulfonic acid-CsPbBr3 nanosheet dispersion.

[0046] (6) Preparation of zinc bromide post-treatment solution: Weigh 15 mg of zinc bromide and add it to a mixed solvent consisting of 2 mL of n-hexane and 100 μL of oleylamine. Stir at 40 °C for 60 min to obtain zinc bromide post-treatment solution.

[0047] (7) Zinc bromide post-treatment: Add 20 μL of zinc bromide post-treatment solution to the purified p-aminobenzenesulfonic acid-CsPbBr3 nanosheet dispersion obtained in step (5), stir in air for 3-5 min; then, centrifuge at 4000 rpm for 3 min, collect the supernatant, and obtain p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheet dispersion.

[0048] Example 2: Preparation of pristine CsPbBr3 nanosheets

[0049] The preparation was carried out according to the steps of Example 1, except that p-aminobenzenesulfonic acid was not added in step (2) and zinc bromide post-treatment was not performed in step (7) to obtain the original CsPbBr3 nanosheets.

[0050] from Figure 1 It can be seen that both the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets prepared in Example 1 and the original CsPbBr3 nanosheets prepared in Example 2 have good full width at half maximum (FWHM) and small Stokes shift. As can be seen in the inset, the luminescence effect of the modified sample is significantly better than that of the original sample.

[0051] from Figure 2 It can be seen that the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheet sample prepared in Example 1 has a higher photoluminescence quantum yield, which is significantly better than the original CsPbBr3 nanosheet sample prepared in Example 2.

[0052] from Figure 3It can be seen that the CsPbBr3 nanosheet sample synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide prepared in Example 1 still maintains a high PL intensity after 30 days of storage, and the peak value does not change significantly; while the original CsPbBr3 nanosheet sample prepared in Example 2 shows that the peak value shifts to a higher wavelength over time and exhibits a double peak, indicating that the modified sample has better stability.

[0053] The above are merely preferred embodiments of the present invention and are 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, or improvements 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 CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide, characterized in that, Includes the following steps: S1: Cesium carbonate is dissolved in oleic acid, heated and stirred to dissolve, thus preparing a cesium oleate precursor solution; S2: Lead bromide, oleic acid, oleylamine and p-aminobenzenesulfonic acid are dissolved in N,N-dimethylformamide, heated and stirred to dissolve, and a lead source precursor solution containing p-aminobenzenesulfonic acid is prepared. S3: Add the cesium oleate precursor solution to the lead source precursor solution containing p-aminobenzenesulfonic acid, stir and mix to obtain the reaction precursor solution; S4: The reaction precursor solution is injected into toluene to carry out the reaction, and a p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion is obtained. S5: The p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion is centrifuged and redispersed to obtain a purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion. S6: Add zinc bromide to a mixed solvent of n-hexane and oleylamine, heat and stir to obtain a zinc bromide post-treatment solution; S7: Add the zinc bromide post-treatment solution to the purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion, stir the reaction and centrifuge, collect the supernatant to obtain p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets. In this process, p-aminobenzenesulfonic acid participates in surface coordination modification during nanosheet growth, and zinc bromide performs halogen replenishment and surface defect passivation on the nanosheets during post-treatment. The two work synergistically to achieve defect suppression.

2. The method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide according to claim 1, characterized in that, The defect suppression includes suppressing ligand desorption, bromine vacancy formation, and nonradiative recombination induced by surface defects.

3. The method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide according to claim 1, characterized in that, In step S1, the solution is first heated and stirred at 120°C until it becomes clear, then the temperature is raised to 150°C and held for 30-60 minutes, and the holding time is 15 minutes. And / or in step S2, the molar ratio of lead bromide to p-aminobenzenesulfonic acid is 1:1-5, the stirring temperature is 40-50℃, and the time is 10-15 min; And / or in step S3, after the cesium oleate precursor solution is added to the lead source precursor solution containing p-aminobenzenesulfonic acid, the stirring time is 3-5 min; And / or in step S4, after the reaction precursor solution is injected into toluene, the reaction time is 30-90 s.

4. The method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide according to claim 1, characterized in that, In step S5, ethyl acetate with a volume twice that of the p-aminobenzenesulfonic acid-modified CsPbBr3 nanosheet dispersion is added and centrifuged at a speed of 6000-10000 rpm for 5 min. The solvent used for redispersion is n-hexane.

5. The method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide according to claim 1, characterized in that, In step S6, the mixed solvent is composed of n-hexane and oleylamine, the heating temperature is 40-50℃, the stirring time is 60 min, and the concentration of zinc bromide in the zinc bromide post-treatment solution is 10-80 mmol / L.

6. The method for preparing CsPbBr3 nanosheets synergistically passivated by p-aminobenzenesulfonic acid / zinc bromide according to claim 1, characterized in that, In step S7, after adding the purified p-aminobenzenesulfonic acid modified CsPbBr3 nanosheet dispersion to the zinc bromide posttreatment solution, the mixture is stirred in air for 3-5 min, centrifuged at 4000 rpm for 3 min; and / or the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation CsPbBr3 nanosheets are stored in a refrigerator at 0-10℃.

7. A p-aminobenzenesulfonic acid / zinc bromide synergistic passivation method for CsPbBr3 nanosheets, characterized in that, It is prepared by the method described in any one of claims 1 to 6 for the preparation of CsPbBr3 nanosheets synergistically passivated with p-aminobenzenesulfonic acid / zinc bromide.

8. Application of the p-aminobenzenesulfonic acid / zinc bromide synergistic passivation of CsPbBr3 nanosheets in optoelectronic functional devices.

9. The application according to claim 8, characterized in that, The p-aminobenzenesulfonic acid / zinc bromide synergistic passivation of CsPbBr3 nanosheets is used as a luminescent material or luminescent conversion layer material for optoelectronic functional devices.

10. The application according to claim 8, characterized in that, The optoelectronic functional devices include light-emitting diodes, display devices, solid-state lighting devices, photodetectors, or solar cells.

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