Surface ligand precursor solution of blue light perovskite quantum dots

Abstract

The invention relates to the technical field of perovskite quantum dots, in particular to a surface ligand precursor solution of blue-light perovskite quantum dots, which is prepared by the following steps: preparing a cesium / rubidium precursor and a zinc / lead halide precursor solution, quickly thermally injecting the cesium / rubidium precursor solution into the zinc / lead halide precursor solution, adding ethyl acetate, and performing centrifugal purification to obtain a coarse precipitate; and dropwise adding methylbenzene for dissolving, centrifuging and purifying to obtain quantum dot precipitates, and uniformly dispersing the quantum dot precipitates into normal octane to obtain the quantum dot. According to the blue-light perovskite quantum dot, rubidium and zinc are co-doped to form a more stable perovskite crystal form with halide ions, a surface ligand precursor solution of the blue-light perovskite quantum dot is formed, chloride ions, rubidium ions and zinc ions have higher tolerance factors, a more regular crystal structure is formed, the ion radius of rubidium is smaller than that of cesium, and the blue-light perovskite quantum dot is more stable. Quantum dot crystal lattices are shrunk after rubidium doping, Zn-Cl bonds are more stable than Pb-Cl bonds due to zinc doping, chloride ion vacancy defects are reduced, and the stability of the quantum dots is improved.

Description

Technical Field

[0001] The invention relates to the technical field of perovskite quantum dots, and in particular to a surface ligand precursor solution of blue light perovskite quantum dots. Background Art

[0002] Blue light perovskite quantum dots are a kind of nanomaterial with excellent optical properties. Its basic structure is ABX3, where A is usually an organic or inorganic cation (such as cesium Cs + , methylamine CH3NH3 + ), B is a metal cation (such as lead Pb 2+ , Tin 2+ ), X is a halogen anion (such as bromine Br - , chlorine - ), these quantum dots have been widely used in the optoelectronic field due to their high photoluminescence quantum yield (PLQY), narrow emission spectrum and tunable emission wavelength, showing excellent optical properties.

[0003] Existing blue light perovskite quantum dots easily produce chloride ions (Cl - ) vacancy defects lead to increased non-radiative recombination, reduced fluorescence quantum yield, and also cause the quantum dot lattice structure to be irregular, reducing the stability of the optical properties of the quantum dots and making their fluorescence intensity and luminescence wavelength prone to changes. In addition, the Pb-Cl bonds in the existing quantum dots are relatively weak and easily broken under the influence of environmental factors, further promoting defect formation, resulting in a decrease in the reliability and performance of blue light perovskite quantum dots in practical applications. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a surface ligand precursor solution of blue light perovskite quantum dots.

[0005] A surface ligand precursor solution of blue light perovskite quantum dots is prepared by the following steps: (1) preparing a cesium / rubidium precursor solution: stirring and dissolving cesium carbonate and rubidium carbonate in a mixed solvent A, evacuating the mixture at 100-120° C. for 30 min, and heating the mixture to 140-150° C. under a nitrogen atmosphere to obtain a cesium / rubidium precursor solution; (2) preparing a zinc / lead halide precursor solution: stirring and dissolving zinc bromide, lead bromide and lead chloride in a mixed solvent B, evacuating the mixture at 110-130° C. for 30 min, and heating the mixture to 170-180° C. under a nitrogen atmosphere to obtain a zinc / lead halide precursor solution; (3) Hot injection synthesis reaction: inject the cesium / rubidium precursor solution into the zinc / lead halide precursor solution, react for 40-60 seconds, and then cool in an ice water bath to obtain a crude quantum dot solution; (4) Purifying the crude quantum dot solution: mixing the crude quantum dot solution and ethyl acetate in a volume ratio of 1:1, and centrifuging to obtain a crude precipitate; Take the crude precipitate and add 3 parts by volume of toluene to dissolve it, and centrifuge and purify it at a volume ratio of toluene:ethyl acetate of 3:1 to obtain a quantum dot precipitate; (5) Dispersion and preservation: The purified quantum dot precipitate is evenly dispersed in 1.5 parts by volume of n-octane to obtain a surface ligand precursor solution of blue light perovskite quantum dots.

[0006] Wherein, the mixed solvent A is oleic acid and octadecene; the mixed solvent B is oleic acid, oleylamine, trioctylphosphine and octadecene; Furthermore, in step (1), the molar ratio of cesium carbonate to rubidium carbonate is 1:0.2, and the molar ratio of cesium carbonate to mixed solvent A is 1 mol:45-65 mL.

[0007] Furthermore, in step (1), the volume ratio of oleic acid to octadecene in the mixed solvent A is 1:8-12.

[0008] Furthermore, in step (2), the molar ratio of zinc bromide, lead bromide and lead chloride is 15-20:1:10-12, and the molar ratio of zinc bromide to mixed solvent B is 0.02-0.04 g:10 mL.

[0009] Furthermore, in step (2), the volume ratio of oleic acid, oleylamine, trioctylphosphine and octadecene in the mixed solvent B is 1-2:1-2:1-2:4-6.

[0010] Furthermore, in step (3), the volume ratio of the cesium / rubidium precursor solution to the zinc / lead halide precursor solution is 0.6-1:10.

[0011] Furthermore, in step (1), the stirring speed of the cesium / rubidium precursor solution is 500-700 r / min.

[0012] Furthermore, in step (2), the stirring speed of the zinc / lead halide precursor solution is 800-1200 r / min.

[0013] Furthermore, in step (4), the centrifugal purification rate is 7000-9000 r / min, and the time is 3-5 minutes.

[0014] Furthermore, in step (5), the surface ligand precursor solution of the blue light perovskite quantum dots is sealed and stored in a nitrogen atmosphere.

[0015] The technical solution provided by the present invention includes the following beneficial effects: 1. The present invention forms a more stable perovskite crystal by co-doping rubidium and zinc with halogen ions to form a surface ligand precursor solution of blue light perovskite quantum dots, which can improve the stability of quantum dots. - ) and rubidium ions (Rb + )、Zn ion(Zn 2+ ) has a higher tolerance factor and forms a more regular crystal structure. The ionic radius of rubidium is smaller than that of cesium. Rubidium doping causes the quantum dot lattice to shrink. Zinc doping makes the Zn-Cl bond more stable than the Pb-Cl bond, reduces the formation of chloride ion vacancy defects, improves the radiation recombination ratio, and improves the stability of the lattice, thereby improving the optical performance and reliability of blue light perovskite quantum dots.

[0016] 2. The present invention can improve the luminescence performance of quantum dots by doping quantum dots. Rubidium doping causes the lattice to tilt and increase the band gap, optimizes the lattice structure, and zinc doping improves the lattice stability, reduces defects, and the size effect enhances the bimolecular radiation recombination and improves the overall luminescence efficiency.

[0017] 3. The present invention can reduce the hole injection barrier, optimize the energy band structure, and improve the carrier transmission efficiency by doping quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a flow chart for preparing the surface ligand precursor solution of blue light perovskite quantum dots used in the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] Example 1: A surface ligand precursor solution of a blue light perovskite quantum dot, such as Figure 1 As shown, it is prepared by the following steps: (1) Preparation of cesium / rubidium precursor solution: 0.1 mol cesium carbonate and 0.02 mol rubidium carbonate were stirred and dissolved in 5.5 ml of mixed solvent A (oleic acid and octadecene, volume ratio 1:10), vacuumed at 120 °C for 30 min, and heated to 140 °C under nitrogen atmosphere to obtain cesium / rubidium precursor solution. The stirring speed was 600 r / min. (2) Preparation of zinc / lead halide precursor solution: 0.03 g zinc bromide, 0.0028 g lead bromide and 0.022 g lead chloride were stirred and dissolved in 10 mL mixed solvent B (oleic acid, oleylamine, trioctylphosphine and octadecene in a volume ratio of 1.5:1.5:1.5:5), vacuumed at 120 °C for 30 min, and heated to 180 °C under a nitrogen atmosphere to obtain a zinc / lead halide precursor solution. The stirring speed was 1000 r / min; (3) Hot injection synthesis reaction: 0.8 mL of cesium / rubidium precursor solution was quickly injected into 10 mL of 180°C zinc / lead halide precursor solution. After reacting for 60 seconds, the solution was quickly cooled in an ice water bath to obtain a crude quantum dot solution. (4) Purification of the crude quantum dot solution: The crude quantum dot solution and ethyl acetate were mixed in a volume ratio of 1:1, and centrifuged at 8000 r / min for 3 minutes to obtain a crude precipitate; 3 mL of toluene was added dropwise to the crude precipitate to dissolve it, and the mixture was centrifuged at 8000 r / min for 3 minutes in a volume ratio of toluene:ethyl acetate of 3:1 to obtain a quantum dot precipitate; (5) Dispersion and storage: The purified quantum dot precipitate was evenly dispersed in 1.5 mL of n-octane to obtain a surface ligand precursor solution of blue light perovskite quantum dots, which was then sealed and stored in a glove box with a nitrogen atmosphere.

[0021] Example 2: A surface ligand precursor solution of a blue light perovskite quantum dot, such as Figure 1 As shown, it is prepared by the following steps: (1) Preparation of cesium / rubidium precursor solution: 0.1 mol cesium carbonate and 0.02 mol rubidium carbonate were stirred and dissolved in 5.5 ml of mixed solvent A (oleic acid and octadecene, volume ratio 1:10), vacuumed at 110 °C for 30 min, and heated to 145 °C under nitrogen atmosphere to obtain cesium / rubidium precursor solution. The stirring speed was 700 r / min. (2) Preparation of zinc / lead halide precursor solution: 0.03 g zinc bromide, 0.0028 g lead bromide and 0.022 g lead chloride were stirred and dissolved in 10 mL mixed solvent B (oleic acid, oleylamine, trioctylphosphine and octadecene in a volume ratio of 1.5:1.5:1.5:5), vacuumed at 120 °C for 30 min, and heated to 170 °C under a nitrogen atmosphere to obtain a zinc / lead halide precursor solution. The stirring speed was 900 r / min. (3) Hot injection synthesis reaction: 0.8 mL of cesium / rubidium precursor solution was quickly injected into 10 mL of 170°C zinc / lead halide precursor solution. After reacting for 50 seconds, the solution was quickly cooled in an ice water bath to obtain a crude quantum dot solution. (4) Purification of the crude quantum dot solution: The crude quantum dot solution and ethyl acetate were mixed at a volume ratio of 1:1, and centrifuged at 9000 r / min for 3 minutes to obtain a crude precipitate; 3 mL of toluene was added dropwise to the crude precipitate to dissolve it, and the mixture was centrifuged at 9000 r / min for 3 minutes at a volume ratio of toluene:ethyl acetate of 3:1 to obtain a quantum dot precipitate; (5) Dispersion and storage: The purified quantum dot precipitate was evenly dispersed in 1.5 mL of n-octane to obtain a surface ligand precursor solution of blue light perovskite quantum dots, which was then sealed and stored in a glove box with a nitrogen atmosphere.

[0022] Example 3: A surface ligand precursor solution of a blue light perovskite quantum dot, such as Figure 1 As shown, it is prepared by the following steps: (1) Preparation of cesium / rubidium precursor solution: 0.1 mol cesium carbonate and 0.02 mol rubidium carbonate were stirred and dissolved in 4.5 ml of mixed solvent A (oleic acid and octadecene, volume ratio 1:8), vacuumed at 120 °C for 30 min, and heated to 140 °C under nitrogen atmosphere to obtain cesium / rubidium precursor solution. The stirring speed was 600 r / min. (2) Preparation of zinc / lead halide precursor solution: 0.03 g zinc bromide, 0.0028 g lead bromide and 0.022 g lead chloride were stirred and dissolved in 10 mL of mixed solvent B (oleic acid, oleylamine, trioctylphosphine and octadecene in a volume ratio of 1:2:2:5), vacuumed at 120 °C for 30 min, and heated to 180 °C under a nitrogen atmosphere to obtain a zinc / lead halide precursor solution. The stirring speed was 1000 r / min. (3) Hot injection synthesis reaction: 0.6 mL of cesium / rubidium precursor solution was quickly injected into 10 mL of 180°C zinc / lead halide precursor solution. After reacting for 60 seconds, the solution was quickly cooled in an ice water bath to obtain a crude quantum dot solution. (4) Purification of the crude quantum dot solution: The crude quantum dot solution and ethyl acetate were mixed in a volume ratio of 1:1, and centrifuged at 8000 r / min for 3 minutes to obtain a crude precipitate; 3 mL of toluene was added dropwise to the crude precipitate to dissolve it, and the mixture was centrifuged at 8000 r / min for 3 minutes in a volume ratio of toluene:ethyl acetate of 3:1 to obtain a quantum dot precipitate; (5) Dispersion and storage: The purified quantum dot precipitate was evenly dispersed in 1.5 mL of n-octane to obtain a surface ligand precursor solution of blue light perovskite quantum dots, which was then sealed and stored in a glove box with a nitrogen atmosphere.

[0023] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A surface ligand precursor solution of blue light perovskite quantum dots, characterized in that: The method is prepared by the following steps: (1) preparing a cesium / rubidium precursor solution: stirring and dissolving cesium carbonate and rubidium carbonate in a mixed solvent A, evacuating the mixture at 100-120° C. for 30 min, and heating the mixture to 140-150° C. under a nitrogen atmosphere to obtain a cesium / rubidium precursor solution; (2) preparing a zinc / lead halide precursor solution: stirring and dissolving zinc bromide, lead bromide and lead chloride in a mixed solvent B, evacuating the mixture at 110-130° C. for 30 min, and heating the mixture to 170-180° C. under a nitrogen atmosphere to obtain a zinc / lead halide precursor solution; (3) Hot injection synthesis reaction: inject the cesium / rubidium precursor solution into the zinc / lead halide precursor solution, react for 40-60 seconds, and then cool in an ice water bath to obtain a crude quantum dot solution; (4) Purifying the crude quantum dot solution: mixing the crude quantum dot solution and ethyl acetate in a volume ratio of 1:1, and centrifuging to obtain a crude precipitate; Take the crude precipitate and drop 3 parts by volume of toluene to dissolve it, and centrifuge and purify it at a toluene:ethyl acetate volume ratio of 3:1 to obtain a quantum dot precipitate; (5) Dispersion and storage: The purified quantum dot precipitate is evenly dispersed in 1.5 parts by volume of n-octane to obtain a surface ligand precursor solution of blue light perovskite quantum dots; Wherein, the mixed solvent A is oleic acid and octadecene; the mixed solvent B is oleic acid, oleylamine, trioctylphosphine and octadecene.

2. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (1), the molar ratio of cesium carbonate to rubidium carbonate is 1:0.2, and the molar ratio of cesium carbonate to mixed solvent A is 1 mol:45-65 mL.

3. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (1), the volume ratio of oleic acid to octadecene in the mixed solvent A is 1:8-12.

4. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (2), the molar ratio of zinc bromide, lead bromide and lead chloride is 15-20:1:10-12, and the molar ratio of zinc bromide to mixed solvent B is 0.02-0.04 g:10 mL.

5. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (2), the volume ratio of oleic acid, oleylamine, trioctylphosphine and octadecene in the mixed solvent B is 1-2:1-2:1-2:4-6.

6. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (3), the volume ratio of the cesium / rubidium precursor solution to the zinc / lead halide precursor solution is 0.6-1:

10.

7. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (1), the stirring speed of the cesium / rubidium precursor solution is 500-700 r / min.

8. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (2), the stirring speed of the zinc / lead halide precursor solution is 800-1200 r / min.

9. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (4), the centrifugal purification rate is 7000-9000 r / min, and the time is 3-5 minutes.

10. The surface ligand precursor solution of blue light perovskite quantum dots according to claim 1, characterized in that: In step (5), the surface ligand precursor solution of the blue light perovskite quantum dots is sealed and stored in a nitrogen atmosphere.

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