Agricultural light conversion film and preparation and application thereof

Abstract

The application provides an agricultural light conversion film and preparation and application thereof, and relates to a polysiloxane-wrapped quantum dot technology. Specifically, two alkyl siloxanes are used for polymerization, and the use ratio of the two is controlled, so that the type and quantity of the substituents on the polysiloxane are controlled, the light-emitting efficiency and the life of the quantum dots are significantly improved, and the agricultural light conversion film with better service life can be obtained, and the use cost is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of agricultural composite film, and particularly relates to an agricultural light conversion film and preparation and application thereof. BACKGROUND

[0002] As a large agricultural country, modern agriculture has developed greatly in China. In actual agricultural production, more and more technologies such as greenhouses are used for planting vegetables, fruits and the like, so as to improve the growth rate and yield of plants. On this basis, in order to fully absorb the energy of sunlight for photosynthesis, the agricultural light conversion film emerges as the times require.

[0003] The agricultural light conversion film can convert relatively short-wavelength light such as ultraviolet light and yellow-green light in sunlight into relatively long-wavelength light, and the relatively long-wavelength light is more conducive to absorption by plants, that is, the light spectrum that is not conducive to plant growth is converted into a light spectrum that is more conducive to photosynthesis and growth of plants, so as to improve the utilization efficiency of sunlight. Many documents in the prior art disclose agricultural light conversion films, and one of the core technologies of the agricultural light conversion film is light conversion material. The existing light conversion material includes rare earth compounds, quantum dots and the like, but all of them have problems such as low stability and short service life, and are not suitable for use in agricultural production and cannot be used for a long time.

[0004] Patent ZL201910610449.2 discloses a quantum dot composite light conversion material and a light conversion film, in which polysiloxane is used to wrap quantum dots CuInS2@ZnS. The service life of the light conversion material and the light conversion film obtained by the patent is at most 2 years and 6 months. Although the service life is improved to a certain extent, there is still a great demand and space for improvement in service life and the like for agricultural production. SUMMARY

[0005] The present application provides an agricultural light conversion film, which comprises a quantum dot composite light conversion material wrapped by polysiloxane.

[0006] In some embodiments, the quantum dots are preferably CuInS2:ZnS quantum dots.

[0007] In some embodiments, the polysiloxane is polysiloxane polymerized from two kinds of alkoxysilane.

[0008] In some embodiments, the first alkoxysilane is tetramethoxysilane or tetraethylsiloxane.

[0009] In some embodiments, the second alkoxysilane is n-propyltrimethoxysilane, urea propyltrimethoxysilane, n-dodecyltrimethoxysilane or dimethoxymethylvinylsilane; preferably n-propyltrimethoxysilane.

[0010] In some embodiments, the weight ratio of the first alkoxy silane to the second alkoxy silane is 1-20:20:1, preferably 1-10:10-1; more preferably 1-1.5:1.5-1; further preferably 1:1;

[0011] In some embodiments, the amount of quantum dots in the polysiloxane-encapsulated quantum dot composite light conversion material is 1 / 100-1 / 500 of the total mass of the first alkoxy silane and the second alkoxy silane, preferably 1 / 199;

[0012] In some embodiments, the agricultural light conversion film comprises a quantum dot-containing film layer comprising the polysiloxane-encapsulated quantum dot composite light conversion material;

[0013] In some embodiments, the agricultural light conversion film, the polysiloxane-encapsulated quantum dot composite light conversion material is located in the quantum dot-containing film layer;

[0014] In some embodiments, the quantum dot-containing film layer comprises the polysiloxane-encapsulated quantum dot composite light conversion material and a substrate, which can be PE or PET; the polysiloxane-encapsulated quantum dot composite light conversion material and the substrate can be 1:100-500, preferably 1:200;

[0015] In some embodiments, the quantum dot-containing film layer optionally further comprises one or more of an antioxidant, a diffusing agent, etc.

[0016] In some embodiments, the thickness of the quantum dot-containing film layer can be 100-200 μm, preferably 150 μm;

[0017] In some embodiments, the quantum dot-containing film layer further comprises a substrate layer on both sides; the substrate layers on both sides can be the same or different;

[0018] In some embodiments, the substrate layer can be a PE film layer, a PET film or a barrier film;

[0019] In some embodiments, the thickness of the substrate layer can be 75-150 μm, preferably 100 μm;

[0020] The present application also provides a polysiloxane-encapsulated quantum dot composite light conversion material;

[0021] In some embodiments, the quantum dots are preferably CuInS2:ZnS quantum dots;

[0022] In some embodiments, the polysiloxane is a polysiloxane polymerized from two alkoxy silanes;

[0023] In some embodiments, the first alkoxysilane is tetramethoxysilane or tetraethylsiloxane;

[0024] In some specific embodiments, the second alkoxysilane is n-propyltrimethoxysilane, ureapropyltrimethoxysilane, n-dodecyltrimethoxysilane or dimethoxymethylvinylsilane; preferably n-propyltrimethoxysilane;

[0025] In some specific embodiments, the weight ratio of the first alkoxysilane to the second alkoxysilane is 1-20:20:1, preferably 1-10:10-1; more preferably 1-1.5:1.5-1; further preferably 1:1;

[0026] In some specific embodiments, the amount of quantum dots in the polysiloxane-wrapped quantum dot composite light-conversion material is 1 / 100 to 1 / 500 of the total mass of the first alkoxysilane and the second alkoxysilane, preferably 1 / 199;

[0027] The polysiloxane-wrapped quantum dot composite light-conversion material can be used to prepare agricultural light-conversion films.

[0028] The present invention improves the luminous efficiency and lifespan of quantum dots by adjusting the type and number of substituents on the polysiloxane wrapped around the surface of the quantum dots. Specifically, by using two alkyl siloxanes for polymerization and controlling the usage ratio of the two, the type and number of substituents on the polysiloxane are controlled, thereby significantly improving the luminous efficiency and lifespan of the quantum dots, thereby obtaining an agricultural light conversion film with a longer service life and reducing the cost of use. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the agricultural light conversion film of the present invention; among the three layers, the middle layer is the film layer containing quantum dots, and the upper and lower layers are substrate layers. DETAILED DESCRIPTION

[0030] Example 1

[0031] 0.029 g of indium trichloride tetrahydrate, 0.017 g of copper chloride dihydrate, and 0.13 g of 3-mercaptopropionic acid were added to 7 mL of water and mixed, magnetically stirred, and sodium hydroxide solution was added dropwise to adjust the pH to 10. The resulting solution was transferred to a tetrafluoroethylene reactor and kept warm in an oven at 130°C for 24 hours to obtain a CuInS2 quantum dot solution.

[0032] To the above CuInS2 quantum dot solution, 0.034 g of zinc sulfate and 0.016 g of thiourea were added successively, and after magnetic stirring, the mixture was kept warm at 140°C for 12 h, cooled to room temperature naturally, and centrifuged. 7 mL of water was added to the obtained solid to obtain a CuInS2:ZnS quantum dot solution.

[0033] Quantum dots, n-propyltrimethoxysilane and tetramethoxysilane were added into the solution at a ratio of 0.5%, 49.75% and 49.75% of the total mass, respectively. 2 mL of CuInS2:ZnS quantum dot solution was added into 40 mL of aqueous solution containing n-propyltrimethoxysilane and tetramethoxysilane. The solution was magnetically stirred for 30 min and allowed to stand for 4 h. The precipitate was filtered, washed and dried to obtain a polysiloxane-wrapped CuInS2:ZnS composite light-conversion material.

[0034] The composite light conversion material was tested and its excitation spectrum and emission spectrum were consistent with those in patent ZL201910610449.2. Figure 1 Basically similar, the main emission peak is about 636nm, indicating that the change of the polysiloxane wrapping material has no significant effect on the light absorption and emission of the light conversion material.

[0035] The efficiency of fluorescent quantum dots was tested and the result showed 85%.

[0036] In outdoor use environments, its luminous half-life and service life can reach more than 3.5 years.

[0037] Example 2

[0038] 0.029 g of indium trichloride tetrahydrate, 0.017 g of copper chloride dihydrate, and 0.13 g of 3-mercaptopropionic acid were added to 7 mL of water and mixed, magnetically stirred, and sodium hydroxide solution was added dropwise to adjust the pH to 10. The resulting solution was transferred to a tetrafluoroethylene reactor and kept warm in an oven at 130°C for 24 hours to obtain a CuInS2 quantum dot solution.

[0039] To the above CuInS2 quantum dot solution, 0.034 g of zinc sulfate and 0.016 g of thiourea were added successively, and after magnetic stirring, the mixture was kept warm at 140°C for 12 h, cooled to room temperature naturally, and centrifuged. 7 mL of water was added to the obtained solid to obtain a CuInS2:ZnS quantum dot solution.

[0040] Quantum dots, ureapropyltrimethoxysilane and tetramethoxysilane were added into the solution at 0.5%, 49.75% and 49.75% of the total mass, respectively. 2 mL of CuInS2:ZnS quantum dot solution was added into 40 mL of aqueous solution containing ureapropyltrimethoxysilane and tetramethoxysilane. The solution was magnetically stirred for 30 min and allowed to stand for 4 h. The precipitate was filtered, washed and dried to obtain a polysiloxane-wrapped CuInS2:ZnS composite light-conversion material.

[0041] The composite light conversion material was tested, and its excitation spectrum and emission spectrum were basically similar to those in Example 1.

[0042] The efficiency of fluorescent quantum dots was tested and the result showed 80%.

[0043] In outdoor use environments, its luminous half-life and service life can reach more than 2.5 years.

[0044] Example 3

[0045] 0.029 g of indium trichloride tetrahydrate, 0.017 g of copper chloride dihydrate, and 0.13 g of 3-mercaptopropionic acid were added to 7 mL of water and mixed, magnetically stirred, and sodium hydroxide solution was added dropwise to adjust the pH to 10. The resulting solution was transferred to a tetrafluoroethylene reactor and kept warm in an oven at 130°C for 24 hours to obtain a CuInS2 quantum dot solution.

[0046] To the above CuInS2 quantum dot solution, 0.034 g of zinc sulfate and 0.016 g of thiourea were added successively, and after magnetic stirring, the mixture was kept warm at 140°C for 12 h, cooled to room temperature naturally, and centrifuged. 7 mL of water was added to the obtained solid to obtain a CuInS2:ZnS quantum dot solution.

[0047] Quantum dots, n-dodecyltrimethoxysilane and tetramethoxysilane were added into the solution at a ratio of 0.5%, 49.75% and 49.75% of the total mass, respectively. 2 mL of CuInS2:ZnS quantum dot solution was added into 40 mL of aqueous solution containing n-dodecyltrimethoxysilane and tetramethoxysilane. The solution was magnetically stirred for 30 min and allowed to stand for 4 h. The precipitate was filtered, washed and dried to obtain a polysiloxane-wrapped CuInS2:ZnS composite light-conversion material.

[0048] The composite light conversion material was tested, and its excitation spectrum and emission spectrum were basically similar to those in Example 1.

[0049] The efficiency of fluorescent quantum dots was tested and the result showed 82%.

[0050] In outdoor environments, its luminous half-life and service life can reach more than 2.25 years.

[0051] Example 4

[0052] 0.029 g of indium trichloride tetrahydrate, 0.017 g of copper chloride dihydrate, and 0.13 g of 3-mercaptopropionic acid were added to 7 mL of water and mixed, magnetically stirred, and sodium hydroxide solution was added dropwise to adjust the pH to 10. The resulting solution was transferred to a tetrafluoroethylene reactor and kept warm in an oven at 130°C for 24 hours to obtain a CuInS2 quantum dot solution.

[0053] To the above CuInS2 quantum dot solution, 0.034 g of zinc sulfate and 0.016 g of thiourea were added successively, and after magnetic stirring, the mixture was kept warm at 140°C for 12 h, cooled to room temperature naturally, and centrifuged. 7 mL of water was added to the obtained solid to obtain a CuInS2:ZnS quantum dot solution.

[0054] Quantum dots, dimethoxymethylvinylsilane and tetramethoxysilane were added into the solution at a ratio of 0.5%, 49.75% and 49.75% of the total mass, respectively. 2 mL of CuInS2:ZnS quantum dot solution was added into 40 mL of aqueous solution containing dimethoxymethylvinylsilane and tetramethoxysilane. The solution was magnetically stirred for 30 min and allowed to stand for 4 h. The precipitate was filtered, washed and dried to obtain a polysiloxane-wrapped CuInS2:ZnS composite light-conversion material.

[0055] The composite light conversion material was tested, and its excitation spectrum and emission spectrum were basically similar to those in Example 1.

[0056] The efficiency of fluorescent quantum dots was tested and the result showed 78%.

[0057] In outdoor use environments, its luminous half-life and service life can reach more than 2 years.

[0058] Example 5

[0059] 0.029 g of indium trichloride tetrahydrate, 0.017 g of copper chloride dihydrate, and 0.13 g of 3-mercaptopropionic acid were added to 7 mL of water and mixed, magnetically stirred, and sodium hydroxide solution was added dropwise to adjust the pH to 10. The resulting solution was transferred to a tetrafluoroethylene reactor and kept warm in an oven at 130°C for 24 hours to obtain a CuInS2 quantum dot solution.

[0060] To the above CuInS2 quantum dot solution, 0.034 g of zinc sulfate and 0.016 g of thiourea were added successively, and after magnetic stirring, the mixture was kept warm at 140°C for 12 h, cooled to room temperature naturally, and centrifuged. 7 mL of water was added to the obtained solid to obtain a CuInS2:ZnS quantum dot solution.

[0061] Quantum dots, n-propyltrimethoxysilane and tetramethoxysilane were added into the solution at a ratio of 0.5%, 94.5% and 5% of the total mass, respectively. 2 mL of CuInS2:ZnS quantum dot solution was added into 40 mL of aqueous solution containing n-propyltrimethoxysilane and tetramethoxysilane. The solution was magnetically stirred for 30 min and allowed to stand for 4 h. The precipitate was filtered, washed and dried to obtain a polysiloxane-wrapped CuInS2:ZnS composite light-conversion material.

[0062] The composite light conversion material was tested, and its excitation spectrum and emission spectrum were basically similar to those in Example 1.

[0063] The efficiency of fluorescent quantum dots was tested and the result showed 79%.

[0064] In outdoor use environments, its luminous half-life and service life can reach more than 2 years.

[0065] Example 6

[0066] 5 parts of the composite light-converting material, 1 part of silicone microspheres, and 100 parts of polyethylene granules were melted and mixed in a plasticator. The resulting granules were then extruded into granules in a pelletizer. The resulting granules were mixed with polyethylene granules at a weight ratio of 1:10 and then used to blow a film containing quantum dots. The polyethylene granules were used to blow the PE layer. Three film heads were used to blow the film, with the quantum dot film in the center and polyethylene film (PE film) on both sides. This resulted in a three-layer light-converting film. The thickness of the quantum dot film in the center was 150 μm, and the thickness of the PE layers on both sides was 100 μm.

[0067] When placed in the same outdoor use environment, it was found that the service life of the light-conversion film prepared using the composite light-conversion material of Example 1 was more than 3.25 years, while the service life of the light-conversion film prepared using the composite light-conversion materials of Examples 2-5 was between 2-2.5 years, indicating that the extension of the luminous half-life and service life of the composite light-conversion material helps to extend the service life of the light-conversion film.

[0068] The embodiments described above are only preferred implementations of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements without departing from the principles of the present invention. These improvements should also be regarded as within the scope of protection of the present invention.

Claims

1. An agricultural light conversion film comprising a quantum dot composite light conversion material encapsulated in polysiloxane; The quantum dots are CuInS2:ZnS quantum dots; The polysiloxane is a polysiloxane formed by the polymerization of two alkoxysilanes; wherein the first alkoxysilane is tetramethoxysilane; and the second alkoxysilane is n-propyltrimethoxysilane; The weight ratio of the first alkoxysilane to the second alkoxysilane is 1:1; The amount of quantum dots in the polysiloxane-wrapped quantum dot composite light-conversion material is 1 / 199 of the total mass of the first alkoxysilane and the second alkoxysilane.

2. The agricultural light conversion film according to claim 1, wherein the agricultural light conversion film comprises a film layer containing quantum dots; the polysiloxane-wrapped quantum dot composite light conversion material is located in the film layer containing quantum dots; The film layer containing quantum dots comprises a quantum dot composite light-conversion material wrapped with polysiloxane and a substrate. The agricultural light conversion film according to claim 2 , wherein the substrate is PE or PET. 4 . The agricultural light conversion film according to claim 2 , wherein the thickness of the film layer containing quantum dots is 100-200 μm. The agricultural light conversion film according to claim 4 , wherein the thickness of the film layer containing quantum dots is 150 μm.

6. The agricultural light conversion film according to claim 2, wherein the film layer containing quantum dots further comprises a substrate layer on both sides; The substrate layer is a PE film layer, a PET film or a barrier film. 7 . The agricultural light conversion film according to claim 6 , wherein the thickness of the substrate layer is 75-150 μm. 8 . The agricultural light conversion film according to claim 7 , wherein the thickness of the substrate layer is 100 μm.

9. The polysiloxane-wrapped quantum dot composite light conversion material contained in the agricultural light conversion film according to claim 1.

10. The polysiloxane-coated quantum dot composite light conversion material according to claim 9 is used to prepare agricultural light conversion films.

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