A heterojunction agricultural light conversion film

Abstract

The present invention discloses a heterojunction agricultural light-conversion film, which belongs to the technical field of agricultural light-conversion films, and comprises the following steps: step one, weighing raw materials CsCl, MnCl2(H2O)4, and SbCl3 according to the stoichiometric ratio of each element, putting the weighed raw materials into an agate mortar, adding deionized water, mixing and grinding, and taking out the vacuum sealing package after completion; step two, using the heterojunction luminescent material obtained in step one and Ecoflex‑0030 silica gel to fully mix in proportion, pour into a special mold, bake in a drying oven, and demould to obtain a heterojunction agricultural light-conversion film. The present invention adopts a heterojunction agricultural light-conversion film of the above structure, and the obtained light-conversion film can effectively utilize solar energy, can improve light conversion efficiency and is harmless to the environment. At the same time, due to the formation of the heterojunction, the red-orange light emission intensity of the material is improved, which promotes plant growth and development and organic matter accumulation.

Description

Technical Field

[0001] The invention relates to the technical field of agricultural light-conversion films, and in particular to a heterojunction agricultural light-conversion film. Background Art

[0002] At present, there are two types of supplementary lighting technologies for plant growth: one is LED supplementary lighting, and the other is traditional agricultural light conversion film. LED supplementary lighting adopts the principle of semiconductor light emission, with high energy conversion efficiency, which can greatly reduce energy consumption compared with traditional light sources. It can achieve uninterrupted lighting all day long, effectively extending the growth cycle of plants, especially in winter or rainy weather, and can give full play to its advantages. At the same time, LED supplementary lighting can adjust the spectrum and light intensity according to the growth needs of plants, promote plant photosynthesis, and improve yield and quality. However, LED supplementary lighting will experience light decay during use due to aging of LED chips, poor heat dissipation and other reasons. In addition, the initial investment cost of LED supplementary lighting is relatively high, and it has a high electricity cost.

[0003] Traditional agricultural light conversion films can convert ultraviolet light into effective light required for plant photosynthesis through greenhouse light conversion film technology, thereby promoting plant growth and development. However, traditional agricultural light conversion films have low light conversion efficiency and poor stability for ultraviolet light. At the same time, their emission spectrum cannot accurately match the absorption spectrum of plant photosynthesis pigments.

[0004] At the same time, the light conversion agent materials currently used in light conversion films are mainly organic dyes and rare earth complexes. Organic dye light conversion agents are usually dye compounds containing large conjugated π bonds, with a rigid planar structure, easily excited by ultraviolet light, and good compatibility with greenhouse films. However, this type of light conversion agent has poor light stability and is prone to oxidative decomposition, resulting in a short service life of the greenhouse film. Most of them have benzene rings or condensed ring structures, and the degradation products pose an environmental pollution risk.

[0005] Rare earth organic complex type light conversion agents use rare earth ions as luminescent centers and organic compounds as ligands, and obtain the complex system through coordination reaction. Most of the organic compounds have high ultraviolet absorption efficiency. Common organic compounds such as conjugated polyolefins, β-diketones, heterocyclic compounds and aromatic carboxylic acids have good ultraviolet light conversion ability and good compatibility with high molecular polymers. To a certain extent, they can overcome the problem of poor stability of organic dye type light conversion agents. However, when this type of light conversion agent is mixed with membrane materials in high doses, ion clusters are easily generated, resulting in uneven distribution of luminescent centers, which will reduce the mechanical properties of the light conversion film and produce fluorescence concentration quenching effect. At the same time, rare earth ions are expensive and mostly present narrow-band emission, which is poorly matched with the effective photosynthesis range of crops. Summary of the invention

[0006] The purpose of the present invention is to provide a heterojunction agricultural light conversion film to solve the above problems.

[0007] To achieve the above-mentioned purpose, the present invention provides a heterojunction agricultural light-conversion film, which is made of CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel, wherein the raw materials for preparing the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material include CsCl, MnCl2(H2O)4, and SbCl3.

[0008] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the specific process of synthesizing the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material is as follows;

[0009] Accurately weigh a certain amount of raw materials CsCl, MnCl2(H2O)4, and SbCl3, put the weighed raw materials into an agate mortar, add a small amount of deionized water to promote uniform mixing between the substances, try to avoid introducing impurities during the grinding process, and ensure that the materials are fully moistened. The heterojunction is quickly synthesized by grinding, and after completion, the product is taken out without drying, and the product is immediately vacuum-sealed to obtain the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material.

[0010] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the specific process of synthesizing the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material is as follows:

[0011] The synthesized CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel are fully mixed in proportion to make the two evenly dispersed, the mixture is poured into a special mold, and gently vibrated to remove bubbles to make the filling more compact, and then placed in a drying oven preheated to an appropriate temperature, cured and shaped under specific conditions, and demolded after baking to obtain the heterojunction agricultural light conversion film.

[0012] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the compound raw materials of each element are weighed according to the stoichiometric ratio of CsMnCl3(H2O)2 / Cs3SbCl6, wherein CsCl is weighed as 0.5051g, MnCl2(H2O)4 is weighed as 0.4452g, and SbCl3 is weighed as 0.1711g.

[0013] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the time for grinding the mixture of CsCl, MnCl2(H2O)4, SbCl3 and deionized water in an agate mortar is 15 minutes.

[0014] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the mixing ratio of the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel is 0.05:1.

[0015] Preferably, in the above-mentioned heterojunction agricultural light-conversion film, the baking condition for the filled mold is baking at 70° C. for 4 hours.

[0016] Therefore, the present invention adopts a heterojunction agricultural light-conversion film of the above structure. The synthetic raw materials of the luminescent material selected by the present invention are cheap and easy to obtain, so the use of the material of the present invention as a light-conversion agent to prepare a light-conversion film can reduce costs to a certain extent, and the material adopts an environmentally friendly mechanochemical method during the synthesis process, and the operation process is simple and convenient, avoiding the high temperature and high pressure environment and the large-scale use of organic solvents, which is convenient for the large-scale preparation of the material. Since the present invention adopts a perovskite material with the advantages of a wide absorption spectrum range, a large Stokes shift, low cost, non-toxic and environmentally friendly, it can effectively utilize solar energy, improve the light conversion efficiency and be harmless to the environment. At the same time, due to the formation of a heterojunction, the red-orange light emission intensity of the material is improved. Due to the emission spectrum characteristics of the material, it can better match the effective light band of plant photosynthesis, thereby improving the degree of spectral matching.

[0017] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a plant growth comparison diagram of a heterojunction agricultural light conversion film embodiment of the present invention, in which leek is used as a research object to study the effect of the light conversion film;

[0019] Figure 2 This is a plant growth comparison diagram of a heterojunction agricultural light conversion film embodiment of the present invention, in which green cabbage is used as a research object to study the effect of the light conversion film;

[0020] Figure 3 This is a test diagram of the absorption spectrum range of the light conversion film material of an embodiment of a heterojunction agricultural light conversion film of the present invention;

[0021] Figure 4 A fluorescence spectrum diagram of a light-conversion film material of a heterojunction agricultural light-conversion film embodiment of the present invention;

[0022] Figure 5 This is a test diagram of light conversion efficiency of an embodiment of a heterojunction agricultural light conversion film of the present invention;

[0023] Figure 6 This is a comparison chart of the PL intensity of pure CsMnCl3(H2O)2 and heterojunction in an embodiment of a heterojunction agricultural light conversion film of the present invention;

[0024] Figure 7 This is an emission spectrum diagram of a heterojunction light conversion film according to an embodiment of a heterojunction agricultural light conversion film of the present invention. DETAILED DESCRIPTION

[0025] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0026] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0027] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0028] Example 1

[0029] Synthesize CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent materials;

[0030] Weigh the compound raw materials of each element according to the stoichiometric ratio of CsMnCl3(H2O)2 / Cs3SbCl6, where 0.5051g of CsCl, 0.4452g of MnCl2(H2O)4, and 0.1711g of SbCl3 are weighed, and the weighed raw materials are placed in an agate mortar, and a small amount of deionized water is added to promote uniform mixing between the substances. During the grinding process, impurities should be avoided as much as possible, and the materials should be ensured to be fully wetted. The grinding time is 15 minutes. The heterojunction is quickly synthesized by grinding. After completion, the product is taken out and immediately vacuum-sealed and packaged to obtain the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material.

[0031] Example 2

[0032] The CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material prepared in Example 1 was used to synthesize the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction agricultural light conversion film:

[0033] The synthesized CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel are fully mixed in proportion. The mixing ratio of CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel is 0.05:1. The two are evenly dispersed. The mixture is poured into a special mold and gently shaken to remove bubbles to make the filling more compact. It is then placed in a drying oven preheated to an appropriate temperature. The baking condition for the filled mold is to bake at 70°C for 4 hours. It is cured and shaped under the above conditions. After baking, the heterojunction agricultural light-conversion film is obtained by demolding.

[0034] In order to evaluate the effects of the heterojunction agricultural light conversion films prepared by the methods of Example 1 and Example 2 on the growth of leeks and green cabbage, three groups of control experiments were designed to compare the growth of plants under different conditions.

[0035] Experimental subjects: Healthy leek and green cabbage seedlings of uniform size were selected as experimental subjects.

[0036] Experimental groups:

[0037] Group 1 (control group): The subjects were completely exposed to natural sunlight without using any light conversion film.

[0038] Group 2 (negative control group): The experimental objects were covered with a transparent mold made of Ecoflex-0030 silicone alone to exclude the influence of the silicone itself on plant growth.

[0039] The third group (experimental group): The experimental objects were covered with a light-converting film prepared by mixing CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel.

[0040] Environmental control: Ensure that all experimental groups are conducted under the same temperature, humidity, watering frequency, and other environmental factors to avoid external variables affecting the experimental results.

[0041] Measurement indicators: For leeks, the main focus is on changes in leaf length; for green cabbage, the focus is on the increase in the number of leaves and changes in the width of a single leaf.

[0042] See attached Figure 1 The following is the growth of leek:

[0043] In the first group, the average length of the leek leaves increased from 6.65 cm on the first day to 11.36 cm on the 13th day.

[0044] In the second group, the average length of leek leaves increased from 7.25 cm to 12.37 cm, showing a similar growth trend as the first group.

[0045] In the third group, the average length of leek leaves increased significantly from 8.13 cm to 15.31 cm, indicating that the light-converting film promoted its faster growth.

[0046] See attached Figure 2 Shown is the growth of green cabbage:

[0047] In the first group, the number of cabbage leaves increased from 7 to 11, and the average leaf width expanded from 3.25 cm to 3.8 cm.

[0048] In the second group, the number of cabbage leaves increased from 8 to 12, and the average leaf width expanded from 3.29 cm to 3.86 cm.

[0049] In the third group, the number of cabbage leaves increased from 8 to 14, and the average leaf width also expanded from 3.33 cm to 4.13 cm, showing a better growth trend.

[0050] The experimental results show that the use of a light-converting film containing a specific heterojunction luminescent material can effectively promote the growth and development of the two crops, which is not only reflected in the increase in stem and leaf length or the number of leaves, but also in the expansion of leaf area. This is because the light-converting film optimizes the light quality and improves the photosynthesis efficiency, thereby accelerating the growth and development of plants. Therefore, it can be seen that the light-converting film made of the light-converting agent of the present invention can promote the growth and development of plants and improve the yield and quality of crops.

[0051] Through the ultraviolet-visible absorption spectrum test, the heterojunction material of the present invention exhibits significant absorption characteristics in the range of 250 nm to 575 nm, covering the ultraviolet to yellow-green light region, confirming its advantage of a wide absorption spectrum, which is conducive to fully capturing multiple wavelengths of energy in sunlight, as shown in Table 1. The obtained light conversion film material can absorb (250nm-575nm) ultraviolet to yellow-green light region, and has a wide absorption range, such as Figure 3 shown.

[0052] Table 1 UV-Visible absorption spectrum test data table

[0053] ;

[0054] A wide absorption spectrum range means that the substance can absorb a wide spectrum range, that is, its absorption peak is distributed in a wide wavelength range. As can be seen from Table 1, the absorption values ​​of wavelengths from 250nm to 650nm vary, among which the absorption value is higher in the short wavelength region (250nm to 450nm), while the absorption value gradually decreases in the long wavelength region (450nm to 650nm). This means that the substance has a wide absorption range, and light from 250nm to 650nm can be well absorbed, indicating that its absorption spectrum range is large.

[0055] Stokes shift refers to the difference between the fluorescence emission wavelength and the absorption wavelength, usually expressed as the wavelength difference from the absorption peak to the emission peak. A large Stokes shift means a large wavelength difference from the absorption spectrum to the fluorescence emission spectrum. Figure 4 It can be seen that the optimal peak of the excitation spectrum is located at a shorter wavelength (345nm), while the peak of the emission spectrum is located at a longer wavelength (625nm). The wavelength difference between the two (280nm) is large, so the Stokes shift is large.

[0056] Table 2 Fluorescence spectrum data table

[0057] ;

[0058] Light conversion efficiency refers to the efficiency of a substance in converting absorbed light energy into fluorescent light energy. Generally, this efficiency is closely related to the intensity of the material's absorption peak, the width of the absorption spectrum, and the characteristics of the fluorescent emission. The absorption value is higher in the short wavelength region (250nm to 450nm), indicating that the substance can absorb light energy better. After absorption, if the substance can efficiently convert it into fluorescence and avoid energy loss, it indicates that the light conversion efficiency is high. A larger absorption range usually also helps to increase the total energy absorption of the material, thereby improving the light conversion efficiency.

[0059] like Figure 5 As shown, after detection and calculation, it can be known that the integrated area of ​​the emission enhancement spectrum in the red light region = 684.26;

[0060] The integrated area of ​​the spectrum with reduced absorption in the blue light region = 2062.36;

[0061] Light conversion efficiency = (integral area of ​​emission enhancement spectrum in red light region / integral area of ​​absorption reduction spectrum in blue light region)*100%=(684.26 / 2062.36)*100%=33.18%;

[0062] The light conversion ability of the transparent film prepared without heterojunction materials is almost undetectable, while the light conversion efficiency of the light conversion film prepared with heterojunction materials is about 33.18%.

[0063] Depend on Figure 6As shown in Table 3, before the heterojunction is formed, the red-orange light emission intensity of the material is very low. After the heterojunction is formed, the emission intensity increases by about 36 times;

[0064] Table 3 Data of pure CsMnCl3(H2O)2 PL intensity and heterojunction PL intensity

[0065] ;

[0066] Figure 7 and Table 4, are the emission spectra of the heterojunction agricultural light conversion films.

[0067] Table 4 Emission spectrum data of heterojunction agricultural light conversion film

[0068] ;

[0069] Therefore, the present invention adopts a heterojunction agricultural light-conversion film of the above structure. The synthetic raw materials of the luminescent material selected by the present invention are cheap and easy to obtain, so the use of the material of the present invention as a light-conversion agent to prepare a light-conversion film can reduce costs to a certain extent, and the material adopts an environmentally friendly mechanochemical method during the synthesis process, and the operation process is simple and convenient, avoiding the high temperature and high pressure environment and the large-scale use of organic solvents, which is convenient for the large-scale preparation of the material. Since the present invention adopts a perovskite material with the advantages of a wide absorption spectrum range, a large Stokes shift, low cost, non-toxic and environmentally friendly, it can effectively utilize solar energy, improve the light conversion efficiency and be harmless to the environment. At the same time, due to the formation of the heterojunction, the red-orange light emission intensity of the material is improved. Due to the emission spectrum characteristics of the material, it can better match the effective light band of plant photosynthesis, thereby improving the degree of spectral matching.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A heterojunction agricultural light conversion film, characterized in that: It is made of CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel, wherein the raw materials for preparing the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material include CsCl, MnCl2(H2O)4, and SbCl3, and the raw materials are weighed according to the stoichiometric ratio of CsMnCl3(H2O)2 / Cs3SbCl6, wherein CsCl is 0.5051g, MnCl2(H2O)4 is 0.4452g, and SbCl3 is 0.1711g.

2. The heterojunction agricultural light conversion film according to claim 1, characterized in that: The specific process of synthesizing CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material is as follows; Accurately weigh the raw materials CsCl0.5051g, MnCl2(H2O)40.4452g, and SbCl30.1711g, put the weighed raw materials into an agate mortar, add a small amount of deionized water to promote uniform mixing between the substances, try to avoid introducing impurities during the grinding process, and ensure that the materials are fully moistened. The heterojunction is quickly synthesized by grinding. After completion, take out the product without drying, and immediately vacuum seal the product to obtain the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material.

3. The heterojunction agricultural light conversion film according to claim 2, characterized in that: The specific process of synthesizing the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction light-emitting material to produce a CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction agricultural light-conversion film is as follows: The synthesized CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel are fully mixed in proportion to make the two evenly dispersed, the mixture is poured into a special mold, and gently vibrated to remove bubbles to make the filling more compact, and then placed in a drying oven preheated to an appropriate temperature, cured and shaped under specific conditions, and demolded after baking to obtain the heterojunction agricultural light conversion film.

4. The heterojunction agricultural light conversion film according to claim 2, characterized in that: The grinding time of CsCl, MnCl2(H2O)4, SbCl3 and deionized water mixture in an agate mortar was 15 min.

5. The heterojunction agricultural light conversion film according to claim 3, characterized in that: The mixing ratio of the CsMnCl3(H2O)2 / Cs3SbCl6 heterojunction luminescent material and Ecoflex-0030 silica gel is 0.05:

1.

6. The heterojunction agricultural light conversion film according to claim 3, characterized in that: The baked condition for the filled mold is baked at 70°C for 4 hours.

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