Friedel salt loaded cesium-lead-bromine-chlorine perovskite quantum dot and preparation method thereof

Abstract

The invention discloses Friedel salt-loaded cesium lead bromine chlorine perovskite quantum dots and a preparation method thereof. The preparation method comprises the following steps: soaking lead plaster in a chlorate-containing solution to obtain a lead chlorine salt solution; then mixing mayenite into the lead chloride salt solution for reaction to obtain a lead-containing Friedel's salt solution; and mixing cesium bromide into the lead-containing Friedel's salt solution, and centrifuging and drying after reaction to obtain the Friedel's salt-loaded cesium-lead-bromine-chlorine perovskite quantum dots. Compared with unloaded cesium-lead-bromine-chlorine perovskite quantum dots, the Friedel salt is loaded to fix heavy metal ions through a layered structure and ion exchange capacity of the Friedel salt, and a framework of the Friedel salt can be combined with the cesium-lead-bromine quantum dots in situ to form a stable composite material. The composite material not only has good luminescence performance, but also shows excellent stability and degradation resistance.

Description

Technical Field

[0001] The invention relates to a Fred salt-loaded cesium lead bromine chlorine perovskite quantum dot and a preparation method thereof. Background Art

[0002] As a highly innovative nanomaterial, quantum dots have shown extremely broad application prospects in many cutting-edge fields such as photoelectric conversion, biomarkers and sensors due to their unique optical and electrical properties. In particular, lead halide perovskite quantum dots have attracted extensive attention and in-depth research in the scientific research community in recent years due to their significant advantages such as flexibly tunable band gaps, high quantum yields and relatively low preparation costs.

[0003] In the field of preparation of lead halide perovskite quantum dots, cesium lead bromine (CsPbBr3) quantum dots have become the focus of research due to their excellent optical properties and relatively stable characteristics. However, the traditional preparation process of cesium lead bromine quantum dots has many disadvantages. On the one hand, the raw materials used are expensive, which greatly increases the preparation cost; on the other hand, the preparation process is extremely complicated, involving many delicate steps and strict condition control, which seriously hinders its large-scale industrial production and wide application. In addition, the stability of quantum dots has always been a key factor affecting their actual application performance. Unstable quantum dots are prone to performance degradation in actual use and cannot meet long-term and reliable application requirements.

[0004] In order to effectively solve the above problems, we actively explore innovative ways to prepare quantum dots with the help of waste resources, aiming to reduce costs while improving the stability of quantum dots. Used lead-acid batteries, as extremely common waste in daily life, contain a large amount of lead resources. If these lead resources can be recycled efficiently, it will not only effectively reduce environmental pollution and practice green environmental protection concepts, but also provide economical raw materials for the preparation of quantum dots, opening up new ways of resource utilization.

[0005] However, the use of lead resources in waste lead-acid batteries to prepare cesium lead bromine quantum dots still faces many severe challenges. First, most of the lead in waste batteries exists in the form of lead acid, which must undergo an appropriate treatment process to be converted into lead salts that can be used to prepare quantum dots. This conversion process requires precise control of reaction conditions and process parameters. Second, how to cleverly introduce other key elements in the preparation process to successfully construct highly stable Fred salt-loaded cesium lead bromine chloride perovskite quantum dots has become an important research direction for current scientific research.

[0006] Based on the above background and actual needs, the present invention innovatively proposes a method for preparing cesium lead bromine-chloroperovskite quantum dots loaded with Fred salt, which not only realizes the efficient recycling of waste lead-acid batteries, significantly reduces the preparation cost of quantum dots, but also greatly improves the stability of quantum dots, and provides a new idea and practical solution for the widespread application of quantum dots in various fields, which has scientific value and practical application significance that cannot be ignored. Summary of the invention

[0007] The present invention aims to solve the problems existing in the above-mentioned prior art and provides a Fred salt-loaded cesium lead bromine chlorine perovskite quantum dot and a preparation method thereof.

[0008] The technical solutions adopted in the present invention are: A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt, Soaking lead paste in chlorine-containing acid solution to obtain lead chloride salt solution; Then the calcium aluminum oxide is mixed into a lead chloride salt solution to react and obtain a lead-containing Fred salt solution; Cesium bromide is then mixed into the lead-containing Friedel salt solution, and after the reaction, the solution is centrifuged and dried to obtain cesium lead bromine chloride perovskite quantum dots loaded with Friedel salt.

[0009] Further, the conditions for soaking the lead paste in the chlorine-containing acid solution are: the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of (0.1-0.8):1, the magnetic stirring is 100-200 rad / s, the reaction time is 1-5 hours, and the reaction temperature is 50-80°C; The lead oxide content in the lead paste is 88-95%, and the liquid-solid mass ratio of the chloric acid liquid to the lead paste is (10-15):1.

[0010] Furthermore, when the lead paste is soaked in the chlorine-containing acid solution, sodium chloride is also added, and the concentration of sodium chloride in the chlorine-containing acid solution is less than 50%.

[0011] Furthermore, after obtaining the lead chloride solution, the pH of the lead chloride solution is adjusted to 8-10, and then calcium aluminum oxide is mixed in. The liquid-solid mass ratio of calcium aluminum oxide mixed in the lead chloride solution is (5-10): 1, the stirring speed is 350-650 rad / s, the reaction time is 2-5h, and the temperature is 25-50°C.

[0012] Furthermore, the liquid-solid mass ratio of cesium bromide mixed into the lead-containing Fred salt solution is (2-15):1, the stirring speed is 300-700 rad / s, and the reaction time is 2-5 hours; the centrifugal speed is 2000-5000 rad / s, the centrifugal time is 3-8 minutes, the drying temperature is 50-80°C, and the drying time is 1-3 hours.

[0013] The present invention also discloses a Fred salt-loaded cesium lead bromine-chloride perovskite quantum dot FS / CsPbCl prepared by the above preparation method. x Br 3-x , x=0.5-1.5.

[0014] Furthermore, the fluorescence wavelength of the quantum dots is 475-510 nm, and the fluorescence quantum yield is 40-85%.

[0015] Furthermore, the lead paste can be extracted from waste lead-acid batteries.

[0016] The present invention has the following beneficial effects: By utilizing the lead resources in waste lead-acid batteries, the present invention not only realizes the reuse of waste materials and reduces resource waste, but also avoids the environmental pollution problems that may be caused by improper treatment of lead-acid batteries. This practice of extracting useful elements from waste and converting them into high-value products is in line with the concepts of circular economy and green chemistry.

[0017] Friedel's salt is a layered compound consisting of alternating cation layers and anion layers. This layered structure gives Friedel's salt a high ion exchange capacity and adsorption capacity, and can effectively fix heavy metal ions such as lead ions. In the layered structure of Friedel's salt, lead ions are located at specific lattice positions in the cation layer or skeleton. According to the crystal properties of Friedel's salt, the interlamellar spacing is large, which can fix heavy metal ions by adsorption while maintaining the stability of the structure. In addition, there may be exchangeable anions in the skeleton of Friedel's salt, which can achieve the fixation function by exchanging with heavy metal ions.

[0018] Cesium lead bromide quantum dots are combined with Fred salts through an in-situ synthesis method to achieve in-situ growth of quantum dots. This combination method not only improves the stability of quantum dots, but also avoids the hoarding phenomenon that may occur in traditional methods. In addition, quantum dots can be anchored in the Fred salt skeleton to form a stable composite structure, thereby inhibiting the aggregation and degradation of quantum dots. In addition, the layered structure of Fred salts provides good support for quantum dots, allowing them to maintain high luminous efficiency and long service life under illumination conditions.

[0019] Compared with unloaded cesium lead bromine chloride perovskite quantum dots, the loading of Fred salt fixes heavy metal ions through its layered structure and ion exchange capacity, and its skeleton can be in situ combined with cesium lead bromine quantum dots to form a stable composite material. This composite material not only has good luminescence properties, but also shows excellent stability and anti-degradation ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1A flow chart was prepared for the present invention. DETAILED DESCRIPTION

[0021] The following is combined with Figure 1 The present invention is further described. Example 1

[0022] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.2:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 24%. The magnetic stirring is 100 rad / s, the reaction time is 1.5 hours, and the reaction temperature is 65°C to obtain a lead chloride solution.

[0023] The lead oxide content in the lead paste is 92%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 13:1.

[0024] 2. The pH of the obtained lead chloride solution is adjusted to 9, and then calcium aluminum oxide is mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum oxide mixed into the lead chloride solution is 8:1, the stirring speed is 500 rad / s, the reaction time is 5 hours, and the temperature is 25°C to obtain a lead-containing Fred salt solution.

[0025] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 8:1, a stirring speed of 500 rad / s, and a reaction time of 5 h to obtain a Friedel salt-loaded cesium lead bromine-chloroperovskite quantum dot solution.

[0026] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3000 rad / s, a centrifugal time of 5 min, a drying temperature of 80 ° C, and a drying time of 1.5 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.1 Br 1.9 , the fluorescence wavelength is 475-480nm, and the fluorescence quantum yield reaches 85%.

[0027] Comparative Example 1 A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in a chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.2:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 24%; the magnetic stirring is 100 rad / s, the reaction time is 1.5 hours, and the reaction temperature is 65°C; a lead chloride solution is obtained.

[0028] The lead oxide content in the lead paste is 92%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 13:1.

[0029] 2. The obtained lead chloride salt solution was mixed with cesium bromide, with a liquid-solid mass ratio of 8:1, a stirring speed of 500 rad / s, and a reaction time of 5 h to obtain a cesium lead bromine chloride perovskite quantum dot solution.

[0030] 3. The obtained cesium lead bromine chloride perovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3000 rad / s, a centrifugal time of 5 min, a drying temperature of 80 ° C, and a drying time of 1.5 h to obtain cesium lead bromine chloride perovskite quantum dots CsPbCl 1.1 Br 1.9 , the fluorescence wavelength was 475-480nm, and the fluorescence intensity reached 32% of the initial value.

[0031] The Fred salt-loaded cesium lead bromine chloride perovskite quantum dots prepared in Example 1 have a fluorescence quantum yield of 85%, indicating that they have a high luminous efficiency. In contrast, the quantum dots prepared without the Fred salt loading step in Comparative Example 1 have a fluorescence intensity of only 32% of the initial value. In contrast, the Fred salt-loaded quantum dots in Example 1 have better fluorescence performance under the same preparation conditions, which indicates that the Fred salt loading may play a role in protecting the quantum dots, reducing the performance attenuation that may occur in the preparation process or subsequent environment of the quantum dots, thereby improving the stability of the quantum dots. Fred salt may form a protective layer on the surface of the quantum dots, preventing external factors (such as oxygen, moisture, etc.) from eroding the quantum dots, allowing the quantum dots to better maintain their structure and performance, thereby showing higher stability and better fluorescence performance. Example 2

[0032] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.1:1, with magnetic stirring at 150 rad / s, reaction time of 4 hours and reaction temperature of 80°C; The lead oxide content in the lead paste is 88%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 10:1.

[0033] 2. The pH of the obtained lead chloride solution was adjusted to 8, and then calcium aluminum oxide was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum oxide mixed into the lead chloride solution was 9:1, the stirring speed was 350 rad / s, the reaction time was 4 hours, and the temperature was 40°C to obtain a lead-containing Fred salt solution.

[0034] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 15:1, a stirring speed of 700 rad / s, and a reaction time of 2.5 h to obtain a Friedel salt-loaded cesium lead bromine-chloroperovskite quantum dot solution.

[0035] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 2000 rad / s, a centrifugal time of 8 min, a drying temperature of 50 ° C, and a drying time of 3 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.3 Br 1.7 , the fluorescence wavelength is 460-470nm, and the fluorescence quantum yield reaches 80%. Example 3

[0036] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.8:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 50%. The magnetic stirring is 200 rad / s, the reaction time is 5 hours, and the reaction temperature is 50°C to obtain a lead chloride solution.

[0037] The lead oxide content in the lead paste is 95%, and the liquid-to-solid mass ratio of chloric acid liquid to lead paste is 15:1.

[0038] 2. The pH of the obtained lead chloride solution is adjusted to 10, and then calcium aluminum oxide is mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum oxide to the lead chloride solution is 5:1, the stirring speed is 650 rad / s, the reaction time is 5 hours, and the temperature is 25°C to obtain a lead-containing Fred salt solution; 3. Cesium bromide was mixed into the lead-containing Friedel salt solution, with a liquid-solid mass ratio of 2:1, a stirring speed of 300 rad / s, and a reaction time of 5 h to obtain a Friedel salt-loaded cesium lead bromine chloride perovskite quantum dot solution; 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 5000 rad / s, a centrifugal time of 3 min, a drying temperature of 80 ° C, and a drying time of 1 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.4 Br 1.6 The fluorescence wavelength is 475-478nm, and the fluorescence quantum yield reaches 48%. Example 4

[0039] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.5:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 10%. The magnetic stirring is 200 rad / s, the reaction time is 4.5 hours, and the reaction temperature is 60°C to obtain a lead chloride solution.

[0040] The lead oxide content in the lead paste is 89%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 14:1.

[0041] 2. The pH of the obtained lead chloride solution was adjusted to 8.5, and then calcium aluminum was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum mixed into the lead chloride solution was 10:1, the stirring speed was 400 rad / s, the reaction time was 3 h, and the temperature was 35°C to obtain a lead-containing Fred salt solution.

[0042] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 5:1, a stirring speed of 500 rad / s, and a reaction time of 2 h to obtain a Friedel salt-loaded cesium lead bromine-chloroperovskite quantum dot solution.

[0043] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 4000 rad / s, a centrifugal time of 4 min, a drying temperature of 65 ° C, and a drying time of 1.5 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.2 Br 1.8 The fluorescence wavelength is 470-480nm, and the fluorescence quantum yield reaches 54%. Example 5

[0044] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.3:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 35%. The magnetic stirring is 180 rad / s, the reaction time is 3.5 hours, and the reaction temperature is 60°C to obtain a lead chloride solution.

[0045] The lead oxide content in the lead paste is 91%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 11:1.

[0046] 2. The pH of the obtained lead chloride solution was adjusted to 9.5, and then calcium aluminum oxide was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum oxide mixed into the lead chloride solution was 7.8:1, the stirring speed was 350 rad / s, the reaction time was 4.5 h, and the temperature was 38°C to obtain a lead-containing Fred salt solution.

[0047] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 7:1, a stirring speed of 380 rad / s, and a reaction time of 2.8 h to obtain a Friedel salt-loaded cesium lead bromine chloride perovskite quantum dot solution.

[0048] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3500 rad / s, a centrifugal time of 3.8 min, a drying temperature of 65 ° C, and a drying time of 1.3 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.0 Br 2.0 , the fluorescence wavelength is 480-490nm, and the fluorescence quantum yield reaches 68%. Example 6

[0049] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.7:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 20%. The magnetic stirring is 180 rad / s, the reaction time is 1.8 hours, and the reaction temperature is 58°C to obtain a lead chloride solution.

[0050] The lead oxide content in the lead paste is 94%, and the liquid-to-solid mass ratio of chloric acid liquid to lead paste is 14:1.

[0051] 2. The pH of the obtained lead chloride solution was adjusted to 9.5, and then calcium aluminum was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum mixed into the lead chloride solution was 9.5:1, the stirring speed was 480 rad / s, the reaction time was 2.5 h, and the temperature was 38°C to obtain a lead-containing Fred salt solution.

[0052] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 8.5:1, a stirring speed of 600 rad / s, and a reaction time of 2.5 h to obtain a Friedel salt-loaded cesium lead bromine-chloroperovskite quantum dot solution.

[0053] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3800 rad / s, a centrifugal time of 3.8 min, a drying temperature of 55 ° C, and a drying time of 2.5 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 1.5 Br 1.5 The fluorescence wavelength is 480-485nm, and the fluorescence quantum yield reaches 73%. Example 7

[0054] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.2:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 35%, the magnetic stirring is 180 rad / s, the reaction time is 1.8 hours, and the reaction temperature is 58°C.

[0055] The lead oxide content in the lead paste is 93%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is 14:1.

[0056] 2. The pH of the obtained lead chloride solution was adjusted to 9.5, and then calcium aluminum was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum mixed into the lead chloride solution was 9.5:1, the stirring speed was 480 rad / s, the reaction time was 3 h, and the temperature was 45°C to obtain a lead-containing Fred salt solution.

[0057] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-to-solid mass ratio of 11:1, a stirring speed of 480 rad / s, and a reaction time of 3.5 h to obtain a Friedel salt-loaded cesium lead bromine chloride perovskite quantum dot solution.

[0058] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3800 rad / s, a centrifugal time of 3.8 min, a drying temperature of 55 ° C, and a drying time of 2.5 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 0.5 Br 2.5 , the fluorescence wavelength is 500-510nm, and the fluorescence quantum yield reaches 40%. Example 8

[0059] A method for preparing cesium lead bromine chlorine perovskite quantum dots loaded with Fred salt comprises the following steps: 1. When the lead paste is soaked in chlorine-containing acid solution, the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of 0.1:1, and then sodium chloride is added, and the concentration of sodium chloride in the chlorine-containing acid solution is 35%. The magnetic stirring is 150 rad / s, the reaction time is 1.9 hours, and the reaction temperature is 56°C.

[0060] The lead oxide content in the lead paste is 92%, and the liquid-to-solid mass ratio of chloric acid liquid to lead paste is 12:1.

[0061] 2. The pH of the obtained lead chloride solution was adjusted to 9.5, and then calcium aluminum oxide was mixed into the lead chloride solution for reaction. The liquid-solid mass ratio of calcium aluminum oxide mixed into the lead chloride solution was 9.5:1, the stirring speed was 480 rad / s, the reaction time was 3 h, and the temperature was 43°C to obtain a lead-containing Fred salt solution.

[0062] 3. Cesium bromide was mixed into the lead-containing Friedel salt solution at a liquid-solid mass ratio of 12:1, a stirring speed of 380 rad / s, and a reaction time of 3.5 h to obtain a Friedel salt-loaded cesium lead bromine chloride perovskite quantum dot solution.

[0063] 4. The obtained Fred salt-loaded cesium lead bromine-chloroperovskite quantum dot solution was centrifuged and dried at a centrifugal speed of 3700 rad / s, a centrifugal time of 3.8 min, a drying temperature of 53 ° C, and a drying time of 2.8 h to obtain Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots FS / CsPbCl 0.8 Br 2.2 The fluorescence wavelength is 485-490nm, and the fluorescence quantum yield reaches 48%.

[0064] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. A method for preparing cesium lead bromine chlorine perovskite quantum dots supported by Fred salt, characterized in that: Soaking lead paste in chlorine-containing acid solution to obtain lead chloride salt solution; Then the mayenite is mixed into a lead chloride salt solution to react and obtain a lead-containing Fred salt solution; Cesium bromide is then mixed into the lead-containing Friedel salt solution, and after the reaction, the solution is centrifuged and dried to obtain cesium lead bromine chloride perovskite quantum dots loaded with Friedel salt.

2. The method for preparing Fred salt-loaded cesium lead bromine-chloroperovskite quantum dots according to claim 1, characterized in that: The conditions for soaking the lead paste in the chlorine-containing acid solution are as follows: the chlorine-containing acid solution is prepared by mixing hydrochloric acid and water in a mass ratio of (0.1-0.8):1, the magnetic stirring is 100-200 rad / s, the reaction time is 1-5 hours, and the reaction temperature is 50-80°C; The lead oxide content in the lead paste is 88-95%, and the liquid-solid mass ratio of chloric acid liquid to lead paste is (10-15):

1.

3. The method for preparing Fred salt-supported cesium lead bromine-chloroperovskite quantum dots according to claim 2, characterized in that: Sodium chloride is also added to the chlorine-containing acid solution, and the concentration of sodium chloride in the chlorine-containing acid solution is ≤50%.

4. The method for preparing Fred salt-supported cesium lead bromine-chloroperovskite quantum dots according to claim 1, characterized in that: After obtaining the lead chloride solution, the pH of the lead chloride solution is first adjusted to 8-10, and then calcium aluminum oxide is mixed in, the liquid-solid mass ratio of calcium aluminum oxide to the lead chloride solution is (5-10): 1, the stirring speed is 350-650 rad / s, the reaction time is 2-5h, and the temperature is 25-50°C.

5. The method for preparing cesium lead bromine-chloroperovskite quantum dots supported by Fred salt according to claim 1, characterized in that: The liquid-solid mass ratio of the lead Fred salt solution to cesium bromide is (2-15):1, the stirring speed is 300-700 rad / s, and the reaction time is 2-5 hours; the centrifugal speed is 2000-5000 rad / s, the centrifugal time is 3-8 minutes, the drying temperature is 50-80°C, and the drying time is 1-3 hours.

6. A cesium lead bromine chlorine perovskite quantum dot loaded with Fred salt prepared by the preparation method according to any one of claims 1 to 5.

7. The Fred salt-supported cesium lead bromine-chloroperovskite quantum dots according to claim 6, characterized in that: The fluorescence wavelength of the quantum dots is 475-510 nm, and the fluorescence quantum yield is 40-85%.

Images