Liquid encapsulated quantum dot nanocomposite light conversion agricultural film and preparation method thereof

Abstract

The present application relates to quantum dot light conversion agricultural film technical field, especially in kind liquid encapsulation quantum dot nanometer composite light conversion agricultural film and preparation method thereof. Including: using one pot method to prepare copper indium sulfide quantum dot solution; the copper indinusulfide quantum dot is coated with zinc sulfide shell layer and is washed, and deep red copper indium sulfide quantum dot powder is obtained;Add ultrapure water, and prepare copper indium sulfide quantum dot colloid solution;Nanoporous membrane is placed in copper indium sulfide quantum dot colloid solution and is soaked fully, and is dried, then the surface of the film is flushed with n-hexane, and copper indium sulfide quantum dot nanoporous luminescent layer film is obtained;Protective layer film is prepared using polymer material and flux;Copper indium sulfide quantum dot nanoporous luminescent layer film is used as intermediate layer, protective layer film is placed on both sides, and hot pressing is formed, and liquid encapsulation quantum dot nanometer composite light conversion agricultural film is obtained.The advantage is that the adverse effects of ultraviolet light on crops are effectively reduced; the environmental temperature is improved; compared with traditional solid-phase encapsulation film, the service life is longer, and the light conversion efficiency is higher.

Description

Technical Field

[0001] This invention relates to the field of quantum dot photoconverting agricultural film technology, and in particular to a liquid-encapsulated quantum dot nanocomposite photoconverting agricultural film and its preparation method. Background Technology

[0002] China is a major agricultural country. With the development of materials and planting techniques, facility agriculture, as an important symbol of modern agriculture, has been widely developed globally, especially in China. Plastic greenhouses have become the main model of facility agriculture, providing crops with a stable growing environment and significantly increasing crop yields. However, this also places higher demands on the performance of covering materials. Different light qualities have varying effects on plant growth and development, photosynthesis, and fruit quality. Blue-violet and red-orange light in sunlight can promote crop growth, while ultraviolet light is detrimental to plant growth and can increase pests and diseases. Yellow-green light, on the other hand, is generally not beneficial to plant growth.

[0003] Quantum dot light-converting agricultural film is a highly efficient form of artificial lighting. It utilizes sunlight to excite the quantum dot material in the agricultural film, enabling it to convert more of the ultraviolet light in sunlight, which is detrimental to plant growth, into red light, which is beneficial to plant growth. Moreover, the heat released during the light conversion process can also raise the temperature inside the greenhouse, reducing carbon emissions from winter heating.

[0004] Traditional quantum dot light-conversion films are made by fusing quantum dot materials with polymers, resulting in the absence of freely moving ligands around the quantum dots. Under prolonged light exposure, the structure of the quantum dots is easily damaged, leading to a significant decrease in light conversion performance. Therefore, there is an urgent need for an optimized preparation method for quantum dot light-conversion agricultural films, enabling the quantum dots in the film to maintain their original performance during long-term use, thereby improving the film's lifespan and light conversion efficiency. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film and its preparation method.

[0006] The primary objective of this invention is to provide a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, specifically comprising the following steps: S1. A one-pot method was used to prepare copper indium sulfide quantum dot solution; S2. Coat copper indium sulfide quantum dots with a zinc sulfide shell and wash them to obtain dark red copper indium sulfide quantum dot powder; add ultrapure water to prepare a copper indium sulfide quantum dot colloidal solution. S3. The nanoporous membrane is fully immersed in a copper indium sulfide quantum dot colloidal solution, dried, and then the membrane surface is rinsed with n-hexane to obtain a copper indium sulfide quantum dot nanoporous light-emitting layer membrane. S4. Prepare a protective film using polymer materials and fluxes; S5. Using a copper indium sulfide quantum dot nanoporous light-emitting layer film as the middle layer and a protective layer film on both sides, hot-press molding is performed to obtain a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film.

[0007] Preferably, step S3 specifically includes the following sub-steps: S301. Place the nanoporous membrane in the copper indium sulfide quantum dot colloidal solution prepared in step S2, place it in a vacuum drying oven, start the vacuum pump to gradually reduce the gas pressure and continue for 45~90min to ensure that the nanoporous membrane completely absorbs the copper indium sulfide quantum dot colloidal solution. S302. Fill the vacuum drying oven with nitrogen and let it stand for 1.5 to 2.5 hours to allow the liquid on the surface of the nanoporous membrane to evaporate. S303. Remove the nanoporous membrane and rinse the surface of the film with n-hexane to obtain a copper indium sulfide quantum dot nanoporous light-emitting layer film.

[0008] Preferably, the concentration of the copper indium sulfide quantum dot colloidal solution is 10~15 mg / mL.

[0009] Preferably, step S2 specifically includes the following sub-steps: S201. Preparation of zinc sulfide solution: Zinc chloride, thiourea and ultrapure water are mixed to obtain zinc sulfide solution; S202. Preparation of coated copper indium sulfide quantum dot stock solution: Add zinc sulfide solution to the copper indium sulfide quantum dot solution prepared in step S1 and mix evenly. Heat the solution under high pressure at 100~121℃ for 80~120min. After the reaction, take out the solution and place it in an ice-water bath for rapid cooling to terminate the reaction and obtain the coated copper indium sulfide quantum dot stock solution. S203. Preparation of copper indium sulfide quantum dot powder: Add 2 to 4 times the volume of anhydrous ethanol to the coated copper indium sulfide quantum dot stock solution, centrifuge and remove the supernatant; add a small amount of ultrapure water and anhydrous ethanol, centrifuge again and remove the supernatant to obtain a precipitate, and dry the precipitate to obtain copper indium sulfide quantum dot powder. S204. Preparation of copper indium sulfide quantum dot colloidal solution: Add ultrapure water to copper indium sulfide quantum dot powder to obtain copper indium sulfide quantum dot colloidal solution.

[0010] Preferably, the molar ratio of zinc chloride to thiourea is 1:1; the centrifugation speed in step S203 is 5000~8000 r / min and the centrifugation time is 8~15 min.

[0011] Preferably, the specific preparation process of the copper indium sulfide quantum dot solution in step S1 is as follows: S101. Add copper source, indium source, sodium citrate, and N-acetyl-L-cysteine ​​to ultrapure water and stir until completely dissolved; S102. Add sodium sulfide solution, mix well, and then add alkaline solvent to adjust the pH to 8-9; S103. The solution prepared in step S102 is heated under high pressure at 100~121℃ for 80~120 min; after the reaction, the solution is taken out and placed in an ice-water bath for rapid cooling to stop the continued growth of quantum dots and obtain a copper indium sulfide quantum dot solution.

[0012] Preferably, the alkaline solvent in step S102 is ammonia, which is added dropwise to adjust the pH to 8.5; the heating time in step S103 is 90 minutes.

[0013] Preferably, the copper source in step S101 is copper nitrate, and the indium source is indium nitrate pentahydrate; the molar ratio of copper nitrate, indium nitrate pentahydrate, sodium citrate, and N-acetyl-L-cysteine ​​is 1:4:4:20; and the concentration of the sodium sulfide solution in step S102 is 1 mol / L.

[0014] Preferably, in step S4, the mass ratio of polymer material to flux is 25-35:1; the polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the flux is one of polyethylene glycol, vinyl bis-stearamide, polyethylene wax, pentaerythritol stearate, aluminate coupling agent, zinc stearate, and titanate coupling agent; and the protective layer film thickness is 0.5-2 mm.

[0015] The second objective of this invention is to provide a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film, which is prepared by a method for preparing a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film.

[0016] Compared with the prior art, the present invention can achieve the following beneficial effects: (1) This invention uses copper indium sulfide (CIS) as a red quantum dot light-converting agent. Its greatest advantage lies in its continuously tunable spectrum. By improving the preparation process, quantum dot materials with different emission bands can be obtained, thereby meeting the wavelength requirements of various plant photosynthesis. Compared with other luminescent materials, CIS quantum dot materials have an ultra-wide absorption spectrum, which can effectively absorb blue-violet light and ultraviolet light in sunlight, especially ultraviolet light. In the application of light-converting agricultural films, it can effectively reduce the adverse effects of ultraviolet light on crops. In addition, CIS quantum dots convert part of the absorbed light energy into heat energy due to non-radiative transitions. Therefore, agricultural films containing CIS quantum dots can also increase the ambient temperature during greenhouse cultivation, which has great market value for the heat preservation needs of greenhouses in cold northern regions.

[0017] (2) This invention utilizes a nanoporous membrane to liquid encapsulate copper indium sulfide quantum dots, allowing the quantum dot material in the film to exist in liquid form. Each quantum dot is surrounded by a large number of freely moving ligands. When the ligands on the quantum dot surface are damaged and detached, the surrounding ligands can continue to assemble with the quantum dot. Therefore, the light-converting agricultural film prepared by this method has a longer service life and higher light conversion efficiency compared to traditional solid-phase encapsulated films. Attached Figure Description

[0018] Figure 1 This is a flowchart of a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to an embodiment of the present invention.

[0019] Figure 2 The emission spectra of the light-converting agricultural films provided in Examples 1-3 and Comparative Example 1 according to the present invention are shown.

[0020] Figure 3 The above are absorption spectra of the photoconverting agricultural films provided in Examples 1-3 and Comparative Example 1 according to the present invention.

[0021] Figure 4 This is a graph showing the change in relative luminescence intensity of the light-converting agricultural film provided in Examples 1-3 and Comparative Example 1 over time. Detailed Implementation

[0022] In the following description, embodiments of the invention will be described with reference to the accompanying drawings. In the description below, the same modules are denoted by the same reference numerals. Where the same reference numerals are used, their names and functions are also the same. Therefore, their detailed description will not be repeated.

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0024] This invention provides a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, specifically including the following steps: S1. A one-pot method was used to prepare copper indium sulfide quantum dot solution; the specific preparation process is as follows: S101. Add copper source, indium source, sodium citrate, and N-acetyl-L-cysteine ​​to ultrapure water and stir until completely dissolved; S102. Add sodium sulfide solution, mix well, and then add alkaline solvent to adjust the pH to 8-9; S103. The solution prepared in step S102 is heated under high pressure at 100~121℃ for 80~120 min; after the reaction, the solution is taken out and placed in an ice-water bath for rapid cooling to stop the continued growth of quantum dots and obtain a copper indium sulfide quantum dot solution. Specifically, the copper source is copper nitrate (Cu(NO3)2), and the indium source is indium nitrate pentahydrate (In(NO3)3·5H2O); the molar ratio of copper nitrate, indium nitrate pentahydrate, sodium citrate, and N-acetyl-L-cysteine ​​is 1:4:4:20; the concentration of sodium sulfide solution is 1 mol / L; the alkaline solvent in step S102 is ammonia water, which is added dropwise to adjust the pH to 8.5; step S103 is carried out in a pressure cooker for 90 minutes.

[0025] S2. Coating copper indium sulfide quantum dots with a zinc sulfide shell and washing them yields deep red copper indium sulfide quantum dot powder; adding ultrapure water prepares a copper indium sulfide quantum dot colloidal solution; the specific preparation process is as follows: S201. Preparation of zinc sulfide solution: Zinc chloride (ZnCl2), thiourea and ultrapure water are mixed to obtain zinc sulfide solution; S202. Preparation of coated copper indium sulfide quantum dot stock solution: Add zinc sulfide solution to the copper indium sulfide quantum dot solution prepared in step S1 and mix evenly. Heat the solution under high pressure at 100~121℃ for 80~120min. After the reaction, remove the solution and cool it rapidly in an ice-water bath to terminate the reaction and obtain a red transparent coated copper indium sulfide quantum dot stock solution. S203. Preparation of copper indium sulfide quantum dot powder: Add 2 to 4 times the volume of anhydrous ethanol to the coated copper indium sulfide quantum dot stock solution, centrifuge and remove the supernatant; add a small amount of ultrapure water and anhydrous ethanol, centrifuge again and remove the supernatant to obtain a precipitate, and dry the precipitate to obtain copper indium sulfide quantum dot powder. S204. Preparation of copper indium sulfide quantum dot colloidal solution: Add ultrapure water to copper indium sulfide quantum dot powder to obtain copper indium sulfide quantum dot colloidal solution; In this step, a small amount of N-acetyl-L-cysteine ​​may also be added; Specifically, the molar ratio of zinc chloride to thiourea is 1:1; step S202 is carried out in a pressure cooker, and the heating time is 90 min; in step S203, the centrifugation speed is 5000~8000 r / min and the centrifugation time is 8~15 min; preferably, the centrifugation speed is 6000 r / min and the centrifugation time is 12 min; the drying method is oven drying; the concentration of the copper indium sulfide quantum dot colloidal solution is 5~15 mg / mL, preferably 10~15 mg / mL.

[0026] S3. Immerse the nanoporous membrane thoroughly in the copper indium sulfide quantum dot colloidal solution prepared in step S2; after immersion, dry it, and then rinse the surface of the film with n-hexane to obtain the copper indium sulfide quantum dot nanoporous light-emitting layer film; the specific preparation process is as follows: S301. Place the nanoporous membrane in the copper indium sulfide quantum dot colloidal solution prepared in step S2, place it in a vacuum drying oven, start the vacuum pump to gradually reduce the gas pressure and continue for 1 hour to ensure that the nanoporous membrane completely absorbs the copper indium sulfide quantum dot colloidal solution. S302. Fill the vacuum drying oven with nitrogen and let it stand for 2 hours to allow the liquid on the surface of the nanoporous membrane to evaporate. S303. Remove the nanoporous membrane and rinse the surface of the film with n-hexane to obtain a copper indium sulfide quantum dot nanoporous light-emitting layer film.

[0027] S4. Prepare a protective film using polymer materials and fluxes; Specifically, polymer materials and flux are added to the blown film machine barrel at a mass ratio of 30:1. The blown film machine die head temperature is set to 150℃, the melting temperature to 170℃, and the rotation speed to 100~300r / min. A protective film is obtained through blow molding. The polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the flux is one of polyethylene glycol, vinyl bis-stearamide, polyethylene wax, pentaerythritol stearate, aluminate coupling agent, zinc stearate, and titanate coupling agent; the thickness of the protective layer film is approximately 0.5~2mm.

[0028] S5. Using a copper indium sulfide quantum dot nanoporous light-emitting layer film as the intermediate layer, and placing the protective layer film on both sides, hot-pressing is performed at 120℃ to obtain a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film (see flowchart). Figure 1 ).

[0029] Example 1 This embodiment provides a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, which specifically includes the following steps: S1. A one-pot method was used to prepare copper indium sulfide quantum dot solution; the specific preparation process is as follows: S101. Add 0.03 mmol copper nitrate (Cu(NO3)2), 0.12 mmol indium nitrate pentahydrate (In(NO3)3·5H2O), 0.12 mmol sodium citrate, 0.6 mmol N-acetyl-L-cysteine ​​and 20 mL ultrapure water to a 50 mL beaker and stir until completely dissolved; S102. Add 0.36 mL of sodium sulfide solution (concentration of 1 mol / L), and the solution quickly changes from colorless and transparent to yellow; add ammonia water dropwise to adjust the pH to 8.5~9; S103. Seal the beaker containing the solution prepared in step S102 with plastic wrap, place it in a pressure cooker, add water to the pressure cooker so that the water level is higher than the liquid being heated, and set the timer for 90 minutes; after the reaction is complete, release the pressure cooker, remove the beaker and place it in an ice-water bath to cool it down, thereby stopping the continued growth of quantum dots and obtaining a copper indium sulfide quantum dot solution.

[0030] S2. Coating copper indium sulfide quantum dots with a zinc sulfide shell and washing them yields deep red copper indium sulfide quantum dot powder; adding ultrapure water prepares a copper indium sulfide quantum dot colloidal solution; the specific preparation process is as follows: S201. Preparation of zinc sulfide solution: Mix 0.12 mmol zinc chloride (ZnCl2), 0.12 mmol thiourea and 5 mL ultrapure water to obtain zinc sulfide solution; S202. Preparation of coated copper indium sulfide quantum dot stock solution: Add zinc sulfide solution to the copper indium sulfide quantum dot solution prepared in step S1 and mix well. Place it in a pressure cooker again and set the timer for 90 minutes. After the reaction is complete, remove the beaker and place it in an ice water bath to cool and terminate the reaction. A red transparent coated copper indium sulfide quantum dot stock solution is obtained. S203. Preparation of copper indium sulfide quantum dot powder: 10 mL of copper indium sulfide quantum dot solution was transferred into a 50 mL centrifuge tube, and 30 mL of anhydrous ethanol was added; the centrifuge tube was placed in a centrifuge and centrifuged at 6000 r / min for 12 min, and the supernatant was discarded; 3 mL of ultrapure water and 10 mL of anhydrous ethanol were added and centrifuged again; after centrifugation, the supernatant was discarded to obtain the precipitate; the precipitate was dried to obtain copper indium sulfide quantum dot powder; S204. Preparation of copper indium sulfide quantum dot colloidal solution: Add ultrapure water to copper indium sulfide quantum dot powder to obtain a copper indium sulfide quantum dot colloidal solution with a concentration of 5 mg / mL.

[0031] S3. Immerse the nanoporous membrane thoroughly in the copper indium sulfide quantum dot colloidal solution prepared in step S2; after immersion, dry it, and then rinse the surface of the film with n-hexane to obtain the copper indium sulfide quantum dot nanoporous light-emitting layer film; the specific preparation process is as follows: S301. Place the nanoporous membrane in the copper indium sulfide quantum dot colloidal solution prepared in step S2, place it in a vacuum drying oven, start the vacuum pump to gradually reduce the gas pressure and continue for 1 hour to ensure that the nanoporous membrane completely absorbs the copper indium sulfide quantum dot colloidal solution. S302. Fill the vacuum drying oven with nitrogen and let it stand for 2 hours to allow the liquid on the surface of the nanoporous membrane to evaporate. S303. Remove the nanoporous membrane and rinse the surface of the film with n-hexane to obtain a copper indium sulfide quantum dot nanoporous light-emitting layer film.

[0032] S4. Preparation of protective film: Polyethylene (PE) granules and flux vinyl bis-stearamide are added to the blown film machine barrel at a mass ratio of 30:1. The blown film machine die temperature is set to 150℃, the melt temperature to 170℃, and the rotation speed to 100~300r / min. The protective film is obtained by blow molding. The thickness of the obtained protective film is about 0.5~2mm.

[0033] S5. Using a copper indium sulfide quantum dot nanoporous light-emitting layer film as the middle layer, and placing a protective layer film on both sides, hot-pressing is performed at 120℃ to obtain a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film.

[0034] The quantum efficiency of the prepared liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film was tested, and the results showed that the quantum efficiency reached 57.8%.

[0035] Example 2 This embodiment provides a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, wherein: in step S204, ultrapure water is added to copper indium sulfide quantum dot powder to obtain a copper indium sulfide quantum dot colloidal solution with a concentration of 10 mg / mL. The remaining preparation steps are the same as in Example 1.

[0036] The quantum efficiency of the prepared liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film was tested, and the results showed that the quantum efficiency reached 68.3%.

[0037] Example 3 This embodiment provides a method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, wherein: in step S204, ultrapure water is added to copper indium sulfide quantum dot powder to obtain a copper indium sulfide quantum dot colloidal solution with a concentration of 15 mg / mL. The remaining preparation steps are the same as in Example 1.

[0038] The quantum efficiency of the prepared liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film was tested, and the results showed that the quantum efficiency reached 65.1%.

[0039] Comparative Example 1 A method for preparing a copper indium sulfide quantum dot photoluminescent agricultural film includes the following steps: S1. A one-pot method was used to prepare copper indium sulfide quantum dot solution; the specific preparation process is as follows: S101. Add 0.03 mmol copper nitrate (Cu(NO3)2), 0.12 mmol indium nitrate pentahydrate (In(NO3)3·5H2O), 0.12 mmol sodium citrate, 0.6 mmol N-acetyl-L-cysteine ​​and 20 mL ultrapure water to a 50 mL beaker and stir until completely dissolved; S102. Add 0.36 mL of sodium sulfide solution (concentration of 1 mol / L), and the solution quickly changes from colorless and transparent to yellow; add ammonia water dropwise to adjust the pH to 8.5; S103. Seal the beaker containing the solution prepared in step S102 with plastic wrap, place it in a pressure cooker, add water to the pressure cooker so that the water level is higher than the liquid being heated, and set the timer for 90 minutes; after the reaction is complete, release the pressure cooker, remove the beaker and place it in an ice-water bath to cool it down, thereby stopping the continued growth of quantum dots and obtaining a copper indium sulfide quantum dot solution.

[0040] S2. Coating copper indium sulfide quantum dots with a zinc sulfide shell and washing them yields deep red copper indium sulfide quantum dot powder; adding ultrapure water prepares a copper indium sulfide quantum dot colloidal solution; the specific preparation process is as follows: S201. Preparation of zinc sulfide solution: Mix 0.12 mmol zinc chloride (ZnCl2), 0.12 mmol thiourea and 5 mL ultrapure water to obtain zinc sulfide solution; S202. Preparation of coated copper indium sulfide quantum dot stock solution: Add zinc sulfide solution to the copper indium sulfide quantum dot solution prepared in step S1 and mix well. Place it in a pressure cooker again and set the timer for 90 minutes. After the reaction is complete, remove the beaker and place it in an ice water bath to cool and terminate the reaction. A red transparent coated copper indium sulfide quantum dot stock solution is obtained. S203. Preparation of copper indium sulfide quantum dot powder: 10 mL of copper indium sulfide quantum dot solution was introduced into a 50 mL centrifuge tube, and 30 mL of anhydrous ethanol was added; the centrifuge tube was placed in a centrifuge and centrifuged at 6000 r / min for 12 min, and the supernatant was discarded; 3 mL of ultrapure water and 10 mL of anhydrous ethanol were added and centrifuged again; after centrifugation, the supernatant was discarded to obtain the precipitate; the precipitate was dried to obtain copper indium sulfide quantum dot powder.

[0041] S3. Copper indium sulfide quantum dot-to-light agricultural film blow molding: The prepared copper indium sulfide quantum dot powder, polyethylene (PE) granules, and flux are added to the barrel of a single screw granulator at a mass ratio of 1:100:3 to prepare a light-emitting masterbatch; the obtained masterbatch is loaded into the barrel of a blown film machine, and the blown film machine is set with a die temperature of 150℃, a melting temperature of 170℃, and a rotation speed of 100~300r / min. Through blow molding, a polyethylene film (light-emitting layer film) containing copper indium sulfide quantum dots is obtained. Protective film hot-press encapsulation: Two layers of polyethylene film are placed on both sides of the polyethylene film containing copper indium sulfide quantum dots obtained in step S3, and then pressed into shape by a hot press.

[0042] The quantum efficiency of the prepared copper indium sulfide quantum dot photoluminescent agricultural film was tested, and the results showed that the quantum efficiency reached 51.5%.

[0043] The performance of the liquid-encapsulated quantum dot nanocomposite phototransfer agricultural films prepared in Examples 1-3 and the copper indium sulfide quantum dot phototransfer agricultural film prepared in Comparative Example 1 was measured; the results are shown in the figure. Figures 2-4 .

[0044] Figure 2 The figures show the emission spectra of the films obtained in Comparative Example 1 and Examples 1-3. It can be seen from the figures that the luminescence intensity of the films prepared in Examples 1-3 is significantly higher than that of Comparative Example 1; while the spectrum of the film in Comparative Example 1 shows a red shift. This is because solid encapsulation prevents the quantum dots from being uniformly dispersed, leading to agglomeration and a red shift in the spectrum; liquid encapsulation can effectively improve the luminescence performance of the film.

[0045] Figure 3 The figures show the absorption spectra of the films obtained in Comparative Example 1 and Examples 1-3. It can be seen from the figures that the light transmittance of the films prepared in Examples 1-3 is significantly higher than that of the comparative examples.

[0046] Figure 4 The graph shows the change in relative luminescence intensity of the films obtained in Comparative Example 1 and Examples 1-3 over time. As can be seen from the graph, the relative luminescence intensity of the liquid-encapsulated quantum dot nanocomposite light-converting agricultural films prepared in Examples 1-3 does not decrease significantly with prolonged use, but the relative luminescence intensity of the solid-encapsulated film prepared in Comparative Example 1 decreases significantly. Therefore, it can be concluded that the stability of the liquid-encapsulated quantum dot nanocomposite light-converting agricultural films prepared in Examples 1-3 is significantly improved compared to the traditional solid-encapsulated film prepared in Comparative Example 1.

[0047] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.

[0048] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, characterized in that: Specifically, the steps include the following: S1. A one-pot method was used to prepare copper indium sulfide quantum dot solution; the specific preparation process is as follows: S101. Add copper source, indium source, sodium citrate, and N-acetyl-L-cysteine ​​to ultrapure water and stir until completely dissolved; S102. Add sodium sulfide solution, mix well, and then add alkaline solvent to adjust the pH to 8-9; S103. The solution prepared in step S102 is heated under high pressure at 100~121℃ for 80~120 min; after the reaction, the solution is taken out and placed in an ice-water bath for rapid cooling to stop the continued growth of quantum dots and obtain a copper indium sulfide quantum dot solution. S2. Coat copper indium sulfide quantum dots with a zinc sulfide shell and wash them to obtain dark red copper indium sulfide quantum dot powder; add ultrapure water to prepare a copper indium sulfide quantum dot colloidal solution; specifically including the following sub-steps: S201. Preparation of zinc sulfide solution: Zinc chloride, thiourea and ultrapure water are mixed to obtain zinc sulfide solution; S202. Preparation of coated copper indium sulfide quantum dot stock solution: Add zinc sulfide solution to the copper indium sulfide quantum dot solution prepared in step S1 and mix evenly. Heat the solution under high pressure at 100~121℃ for 80~120min. After the reaction, take out the solution and place it in an ice-water bath for rapid cooling to terminate the reaction and obtain the coated copper indium sulfide quantum dot stock solution. S203. Preparation of copper indium sulfide quantum dot powder: Add 2 to 4 times the volume of anhydrous ethanol to the coated copper indium sulfide quantum dot stock solution, centrifuge and remove the supernatant; add a small amount of ultrapure water and anhydrous ethanol, centrifuge again and remove the supernatant to obtain a precipitate, and dry the precipitate to obtain copper indium sulfide quantum dot powder. S204. Preparation of copper indium sulfide quantum dot colloidal solution: Add ultrapure water to copper indium sulfide quantum dot powder to obtain copper indium sulfide quantum dot colloidal solution; S3. Immerse the nanoporous membrane thoroughly in a copper indium sulfide quantum dot colloidal solution, dry it, and then rinse the membrane surface with n-hexane to obtain a copper indium sulfide quantum dot nanoporous luminescent layer membrane; specifically including the following sub-steps: S301. Place the nanoporous membrane in the copper indium sulfide quantum dot colloidal solution prepared in step S2, place it in a vacuum drying oven, start the vacuum pump to gradually reduce the gas pressure and continue for 45~90min to ensure that the nanoporous membrane completely absorbs the copper indium sulfide quantum dot colloidal solution. S302. Fill the vacuum drying oven with nitrogen and let it stand for 1.5 to 2.5 hours to allow the liquid on the surface of the nanoporous membrane to evaporate. S303. Take out the nanoporous membrane and rinse the surface of the film with n-hexane to obtain a copper indium sulfide quantum dot nanoporous light-emitting layer film; S4. Prepare a protective film using polymer materials and fluxes; S5. Using a copper indium sulfide quantum dot nanoporous light-emitting layer film as the middle layer and a protective layer film on both sides, hot-press molding is performed to obtain a liquid-encapsulated quantum dot nanocomposite light-converting agricultural film.

2. The method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to claim 1, characterized in that: The concentration of the copper indium sulfide quantum dot colloidal solution is 10~15 mg / mL.

3. The method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to claim 1, characterized in that: The molar ratio of zinc chloride to thiourea is 1:1; the centrifugation speed in step S203 is 5000~8000 r / min and the centrifugation time is 8~15 min.

4. The method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to claim 1, characterized in that: The alkaline solvent in step S102 is ammonia, which is added dropwise to adjust the pH to 8.5; the heating time in step S103 is 90 minutes.

5. The method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to claim 4, characterized in that: In step S101, the copper source is copper nitrate and the indium source is indium nitrate pentahydrate; the molar ratio of copper nitrate, indium nitrate pentahydrate, sodium citrate, and N-acetyl-L-cysteine ​​is 1:4:4:20; and the concentration of sodium sulfide solution in step S102 is 1 mol / L.

6. The method for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film according to claim 1, characterized in that: In step S4, the mass ratio of polymer material to flux is 25-35:1; the polymer material includes at least one of polyethylene, polypropylene, polyvinyl chloride, and polystyrene; the flux is one of polyethylene glycol, vinyl bis-stearamide, polyethylene wax, pentaerythritol stearate, aluminate coupling agent, zinc stearate, and titanate coupling agent; and the protective layer film thickness is 0.5-2 mm.

7. A liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film, characterized in that: It is prepared by the method of any one of claims 1 to 6 for preparing a liquid-encapsulated quantum dot nanocomposite phototransfer agricultural film.

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