Method for improving water stability of cesium bismuth bromide system quantum dots by dendritic organosilicon molecules

Abstract

The application discloses a method for improving water stability of a cesium-bismuth-bromine system quantum dot by using dendritic organosilicon molecules, and the method comprises the following steps: taking Cu2O as a catalyst, blending chloropropyl trimethoxysilane, ethylene glycol and liquid ammonia, and then reacting; after multiple rotary evaporation purifications, 3-aminopropyl trimethoxysilane is separated; Cs3Bi2Br9 QDs precursor liquid and 3-aminopropyl trimethoxysilane are added drop by drop into a mixed solution of oleic acid and anhydrous ethanol respectively, heating and vigorous stirring are conducted to obtain a colloidal solution; after the colloidal solution is cooled to room temperature, centrifugation is conducted, and the precipitate at the bottom is filtered to obtain a colloidal solution of Cs3Bi2Br9 QDs based on 3-aminopropyl trimethoxysilane in-situ modification. The application rapidly synthesizes a high-purity dendritic 3-aminopropyl trimethoxysilane under mild conditions through an intermediate, and further uses the 3-aminopropyl trimethoxysilane to modify Cs3Bi2Br9 QDs to improve water stability of the Cs3Bi2Br9 QDs.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials, specifically relating to a method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules. Background Technology

[0002] Silicon coating is an effective means to improve the water, oxygen, light, and thermal stability of perovskite nanocrystals. Moreover, silicon is a transparent material and has no effect on the optical properties of perovskite nanocrystals; silicon coating can significantly enhance their stability. Traditional silicon coating methods use tetraethyl orthosilicate (TEOS) as a silicon precursor, which is slowly hydrolyzed in a strongly alkaline environment, further accelerating the decomposition of perovskite nanocrystals and thus reducing their stability. For example, researchers have obtained a mesoporous silica-coated composite by stirring pre-prepared perovskite nanocrystals with mesoporous silica in a nonpolar solvent and purifying it, which exhibits excellent thermal stability (Angew. Chem. Int. Ed., 2016, 55: 7924-7929). Researchers have also infused perovskite nanocrystal precursor solutions into silicon channels of varying sizes and then thermally initiated crystallization under vacuum to obtain silicon-coated perovskite nanocrystal composites (J. Am. Chem. Soc., 2016, 138: 13874-13881). Studies have shown that mesoporous silicon not only effectively enhances the stability of perovskite nanocrystals but also allows for control of the particle size of the prepared perovskite nanocrystals through template size, thereby modulating fluorescence color via quantum confinement effects. However, inorganic silicon materials exhibit poor compatibility with perovskite materials, and this compatibility negatively impacts the optical and electrical properties of the composite material.

[0003] Patent publication number CN 107603614 A discloses a method for preparing metal halide perovskite quantum dots. During the synthesis process, fluorine reagents hydrolyze to generate hydroxyl groups. Under the combined action of the hydroxyl groups and fluorocarbon chains, these hydroxyl groups self-assemble and tightly coat the surface of the quantum dots, resulting in stable CsPbBr3 perovskite quantum dots that are dispersed as single particles in water. The surface coating method enhances the water dispersion stability.

[0004] Organosilicon, with its unique organic-inorganic hybrid structure, possesses excellent properties such as resistance to high and low temperatures, oxidation stability, weather resistance, hydrophobicity, and physiological inertness. It can be used to modify perovskite nanocrystals at the molecular level and greatly improve the water stability of perovskite, especially perovskite quantum dot (QD) materials. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing dendritic organosilicon molecules to improve the water stability of quantum dots in a cesium bismuth bromide system. First, a high-purity dendritic 3-aminopropyltrimethoxysilane is rapidly synthesized under mild conditions via an intermediate. Then, it is used to modify Cs3Bi2Br9 QDs to improve their water stability and is used in fluorescent anti-counterfeiting materials.

[0006] This invention is achieved through the following technical solution: A method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules.

[0007] Step 1: Using Cu2O as a catalyst, chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia are mixed and reacted. After multiple rotary evaporation purifications, 3-aminopropyltrimethoxysilane is obtained.

[0008] Step 2: Prepare Cs3Bi2Br9 QDs precursor solution;

[0009] Step 3: Add the Cs3Bi2Br9 QDs precursor solution and 3-aminopropyltrimethoxysilane dropwise to a mixed solution of oleic acid and anhydrous ethanol, respectively. Heat and stir vigorously to obtain a colloidal solution. After the colloidal solution cools to room temperature, centrifuge and filter out the precipitate at the bottom to obtain a Cs3Bi2Br9 QDs colloidal solution modified in situ by 3-aminopropyltrimethoxysilane.

[0010] Furthermore, the mass fraction of the 3-aminopropyltrimethoxysilane and the Cs3Bi2Br9 QDs precursor solution is 1%-20%.

[0011] Furthermore, the mixed solution is a mixture of 0.5 mL oleic acid and 5 mL anhydrous ethanol.

[0012] Furthermore, in step 1, chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia are mixed and reacted at 60-80°C.

[0013] Further, in step 2, 0.0897 g of bismuth bromide and 0.0638 g of cesium bromide are mixed and dissolved in 1 mL of octylamine and stirred continuously at room temperature for 2 h. Then, the mixture is added dropwise to a round-bottom flask containing 50 mL of dimethyl sulfoxide and reacted at 40-50 °C for 0.5 h to obtain the Cs3Bi2Br9 QDs precursor solution.

[0014] Further, in step 3, a certain amount of 3-aminopropyltrimethoxysilane is added dropwise to a mixed solution containing 0.5 mL of oleic acid and 5 mL of anhydrous ethanol while stirring continuously. Then, 0.5 g of Cs3Bi2Br9 QDs precursor solution is added dropwise while stirring continuously. The colloidal solution is obtained by vigorous stirring at 60 °C for 20 min.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: dendritic 3-aminopropyltrimethoxysilane was prepared by chloropropyltrimethoxysilane and ethylene glycol. Using ethylene glycol as a raw material alters the surface properties of the obtained 3-aminopropyltrimethoxysilane, providing compatibility when preparing colloidal solutions. The dendritic 3-aminopropyltrimethoxysilane molecules can modify Cs3Bi2Br9 QDs in situ during the formation of the colloidal colloid, effectively reducing the damage of Cs3Bi2Br9 QDs to surrounding water molecules. It is expected to be used to stabilize fluorescent anti-counterfeiting materials and achieve the expected results. Attached Figure Description

[0016] Figure 1 A route diagram for the preparation of 3-aminopropyltrimethoxysilane.

[0017] Figure 2 Results of inductively coupled plasma atomic emission spectrometry (ICP-AES).

[0018] Figure 3 Normal phase chromatogram of 3-aminopropyltrimethoxysilane obtained in Example 1.

[0019] Figure 4 The 1H NMR spectrum of 3-aminopropyltrimethoxysilane obtained in Example 1.

[0020] Figure 5 The carbon spectrum of 3-aminopropyltrimethoxysilane obtained in Example 1. Detailed Implementation

[0021] The present invention will be further described below with reference to specific embodiments, but the present invention is not limited to the following embodiments.

[0022] The present invention discloses a method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules, the specific steps of which are as follows:

[0023] Step 1: Preparation of 3-aminopropyltrimethoxysilane. Using Cu2O as a catalyst, a certain amount of chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia were mixed and reacted at 60-80℃ for 12 h. After purification by three rotary evaporations, 3-aminopropyltrimethoxysilane was obtained.

[0024] Step 2: Preparation of Cs3Bi2Br9 QDs precursor solution. Mix 0.0897 g bismuth bromide and 0.0638 g cesium bromide in 1 mL octylamine and stir continuously at room temperature for 2 h. Then, add the mixture dropwise to a round-bottom flask containing 50 mL dimethyl sulfoxide and react at 40-50 °C for 0.5 h to obtain the Cs3Bi2Br9 QDs precursor solution.

[0025] Step 3: Preparation of a 3-aminopropyltrimethoxysilane-modified Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent). First, a certain amount of 3-aminopropyltrimethoxysilane was added dropwise to a mixed solution containing 0.5 mL of oleic acid and 5 mL of anhydrous ethanol (with continuous stirring). Then, 0.5 g of Cs3Bi2Br9 QDs precursor solution was added dropwise to the above mixed solution with continuous stirring. The mixture was vigorously stirred at 60 °C for 20 min to obtain a colloidal solution. After the colloidal solution cooled to room temperature, it was centrifuged at 10000 rpm for 10 min, and the large precipitate particles at the bottom were filtered off to obtain a 3-aminopropyltrimethoxysilane-modified Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent).

[0026] Example 1

[0027] Step 1: Preparation of 3-aminopropyltrimethoxysilane. Using Cu₂O as a catalyst, a certain amount of chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia (molar ratio 1:1.2-1.5:3) were mixed and reacted at 70℃ for 12 h. After purification by three rotary evaporations, 3-aminopropyltrimethoxysilane was obtained. The analytical results are as follows: Figures 3-5 As shown.

[0028] Step 2: Preparation of Cs3Bi2Br9 QDs precursor solution. 0.0897 g of bismuth bromide and 0.0638 g of cesium bromide were mixed and dissolved in 1 mL of octylamine. The mixture was stirred continuously at room temperature for 2 h. Then, it was added dropwise to a round-bottom flask containing 50 mL of dimethyl sulfoxide and reacted at 45 °C for 0.5 h to obtain the Cs3Bi2Br9 QDs precursor solution.

[0029] Step 3: Preparation of a 3-aminopropyltrimethoxysilane-modified Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent). First, 0.005 g of 3-aminopropyltrimethoxysilane was added dropwise to a mixed solution containing 0.5 mL of oleic acid and 5 mL of anhydrous ethanol (with continuous stirring). Then, 0.5 g of the Cs3Bi2Br9 QDs precursor solution was added dropwise to the above mixed solution with continuous stirring. The mixture was vigorously stirred at 60 °C for 20 min to obtain a colloidal solution. After the colloidal solution cooled to room temperature, it was centrifuged at 10000 rpm for 10 min, and the large precipitate particles at the bottom were filtered off to obtain a 3-aminopropyltrimethoxysilane-modified Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent).

[0030] Example 2

[0031] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.01g.

[0032] Example 3

[0033] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.02g.

[0034] Example 4

[0035] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.03g.

[0036] Example 5

[0037] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.04 g.

[0038] Example 6

[0039] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.05g.

[0040] Example 7

[0041] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.06g.

[0042] Example 8

[0043] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.07g.

[0044] Example 9

[0045] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.08g.

[0046] Example 10

[0047] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.09 g.

[0048] Example 11

[0049] The other steps are the same as in Example 1, except that the mass of 3-aminopropyltrimethoxysilane in step 3 is 0.1g.

[0050] Comparative Example

[0051] Step 1: Preparation of Cs3Bi2Br9 QDs precursor solution. 0.0897 g bismuth bromide and 0.0638 g cesium bromide were mixed and dissolved in 1 mL octylamine. The mixture was stirred continuously at room temperature for 2 h. Then, it was added dropwise to a round-bottom flask containing 50 mL dimethyl sulfoxide and reacted at 45 °C for 0.5 h to obtain the Cs3Bi2Br9 QDs precursor solution.

[0052] Step 2: Preparation of Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent). 0.5 g of Cs3Bi2Br9 QDs precursor solution was added dropwise to a mixture of 0.5 mL oleic acid and 5 mL anhydrous ethanol while continuously stirring. The mixture was vigorously stirred at 60 °C for 20 min to obtain a colloidal solution. After the colloidal solution cooled to room temperature, it was centrifuged at 10000 rpm for 10 min, and the large precipitate particles at the bottom were filtered off to obtain the Cs3Bi2Br9 QDs colloidal solution (anhydrous ethanol solvent).

[0053] Cs3Bi2Br9 QDs were modified using a dendritic 3-aminopropyltrimethoxysilane encapsulation method to reduce the influence of water on their stability. To understand the difference in bismuth ion concentration before and after dendritic 3-aminopropyltrimethoxysilane modification, we strictly controlled the initial concentration of bismuth ions in the system to be the same. Pure Cs3Bi2Br9 QDs and dendritic 3-aminopropyltrimethoxysilane-modified Cs3Bi2Br9 QDs were diluted with ultrapure water. Finally, inductively coupled plasma atomic emission spectrometry (ICP-AES) was used to detect the bismuth ion concentration in the aqueous solution. Figure 2 As shown, we used the bismuth ion concentration in the pure Cs3Bi2Br9 QDs sample as a standard, and then diluted the pure Cs3Bi2Br9 QDs and the Cs3Bi2Br9 QDs modified with dendritic 3-aminopropyltrimethoxysilane with ultrapure water. The study found that as the amount of dendritic 3-aminopropyltrimethoxysilane increased, the bismuth ion concentration detected by inductively coupled plasma atomic emission spectrometry decreased from the initial 0.3975 ppm to 0.0342 ppm. This indicates that the modification with dendritic 3-aminopropyltrimethoxysilane effectively improved the water stability of the prepared Cs3Bi2Br9 QDs.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules, characterized in that, The steps are as follows: Step 1: Using Cu2O as a catalyst, chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia are mixed in a molar ratio of 1:1.2-1.5:3 and reacted. After repeated rotary evaporation purification, dendritic 3-aminopropyltrimethoxysilane is obtained. Step 2: Prepare Cs3Bi2Br9QDs precursor solution; Step 3: Take the Cs3Bi2Br9QDs precursor solution and the 3-aminopropyltrimethoxysilane obtained in Step 1 and add them dropwise to a mixed solution of oleic acid and anhydrous ethanol, respectively. Heat and stir vigorously to obtain a colloidal solution. After the colloidal solution cools to room temperature, centrifuge and filter out the precipitate at the bottom to obtain a Cs3Bi2Br9QDs colloidal solution modified in situ by 3-aminopropyltrimethoxysilane.

2. The method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules according to claim 1, characterized in that, The mass fraction of the 3-aminopropyltrimethoxysilane and Cs3Bi2Br9QDs precursor solution is 1%-20%.

3. The method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules according to claim 1, characterized in that, The mixed solution is a mixture of 0.5 mL oleic acid and 5 mL anhydrous ethanol.

4. The method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules according to claim 1, characterized in that, In step 1, chloropropyltrimethoxysilane, ethylene glycol, and liquid ammonia are mixed and reacted at 60-80°C.

5. The method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules according to claim 1, characterized in that, In step 2, 0.0897 g of bismuth bromide and 0.0638 g of cesium bromide are mixed and dissolved in 1 mL of octylamine and stirred continuously at room temperature for 2 h. Then, the mixture is added dropwise to a round-bottom flask containing 50 mL of dimethyl sulfoxide and reacted at 40-50 °C for 0.5 h to obtain the Cs3Bi2Br9QDs precursor solution.

6. The method for improving the stability of quantum dot water in a cesium bismuth bromide system using dendritic organosilicon molecules according to claim 1, characterized in that, In step 3, a certain amount of 3-aminopropyltrimethoxysilane obtained in step 1 is added dropwise to a mixed solution containing 0.5 mL of oleic acid and 5 mL of anhydrous ethanol, and the mixture is stirred continuously. Then, 0.5 g of Cs3Bi2Br9QDs precursor solution is added dropwise, and the mixture is stirred continuously. The colloidal solution is obtained by vigorous stirring at 60 °C for 20 min.

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