Light conversion agent, light conversion agent preparation method and light conversion film

Abstract

The invention discloses a light conversion agent, a preparation method of the light conversion agent and a light conversion film.The light conversion film is a europium complex copolymer synthesized by an Eu complex and a rhodamine B derivative in a free radical copolymerization mode, the Eu complex has a double-bond structure exposed outside 5-amino-1, 10-phenanthroline molecules, and the Eu complex has a double-bond structure exposed outside the 5-amino-1, 10-phenanthroline molecules. The double bond position, exposed outside the molecule, of the Eu complex structure is connected by amino and acryloyl chloride through substitution reaction; the structure of the rhodamine B derivative is that the carboxyl of rhodamine B is connected with a double-bond structure exposed outside a molecule; the preparation method of the light conversion agent sequentially comprises the steps of synthesizing 5-acrylamido-1, 10-phenanthroline, synthesizing an Eu complex, synthesizing a rhodamine B derivative and synthesizing the light conversion agent. The light conversion film provided by the invention comprises the light conversion agent. According to the light conversion agent and the light conversion film, ultraviolet light and yellow-green light can be converted into red light, and the utilization rate of sunlight in the plant photosynthesis process is increased.

Description

Technical Field

[0001] The present application relates to the technical field of agricultural light-conversion films, and in particular to a light-conversion agent, a method for preparing the light-conversion agent, and a light-conversion film. Background Art

[0002] With the rapid growth of the world's population, in order to meet the huge demand for food in today's society under the current level of productivity, light conversion film is usually used in agricultural activities to protect plants and increase crop yields. Light conversion film is a functional agricultural film that improves the efficiency of plant light utilization by improving light transmittance and converting light wavelengths through light conversion agents. Light conversion agents in the prior art can usually only convert part of the ultraviolet rays in sunlight into blue-violet light or red-orange light required by plants. In the total energy of the incident solar spectrum, ultraviolet radiation accounts for less than 4%, while visible light accounts for more than 50%. The yellow-green light in visible light is relatively strong, and the prior art lacks light conversion agents that can fully convert yellow-green light into red light, resulting in low utilization of sunlight in the plant production process. The effect of using light conversion film in agricultural activities to increase crop yields is limited.

[0003] In addition, in the actual application of light-converting films, the compatibility of light-converting agents with polymer substrates is poor, resulting in low mechanical properties of the light-converting films, poor dispersibility (easy to form ion clusters, resulting in concentration quenching) and high mobility, which ultimately leads to a decrease in the luminous performance of the light-converting films and greatly reduces their service life. In addition, the commonly used substrates of existing light-converting films are either polyethylene, which is difficult to degrade and will cause environmental pollution, or carboxymethyl cellulose, which is easily soluble in water, causing "white pollution" of the light-converting films and too short service life. Summary of the invention

[0004] In view of the defects existing in the prior art, the present application provides a light conversion agent, a method for preparing a light conversion agent and a light conversion film to solve technical problems such as the inability of the light conversion film in the prior art to effectively utilize the yellow-green light in sunlight, the poor compatibility of the light conversion agent in the light conversion film and the polymer substrate, and the low performance of the existing light conversion film.

[0005] In order to achieve the purpose of the above application, the technical solution provided by this application is as follows:

[0006] A light conversion agent is used for a light conversion film. The light conversion agent is a europium complex copolymer synthesized by free radical copolymerization of an Eu complex and a rhodamine B derivative. The Eu complex has a double bond structure exposed outside the 5-amino-1,10-phenanthroline molecule, and the double bond position exposed outside the molecule of the Eu complex structure is connected by an amino group and acryloyl chloride through a substitution reaction; the structure of the rhodamine B derivative is that a double bond structure exposed outside the molecule is connected to the carboxyl position of rhodamine B, and the rhodamine B derivative is prepared by a substitution reaction between rhodamine B and allyl bromide.

[0007] In one embodiment, the general structural formula of the Eu complex is Eu(TTA)3(Aphen), wherein TTA is 2-thenoyltrifluoroacetone and Aphen is 5-acrylamido-1,10-phenanthroline.

[0008] In one embodiment, the light conversion agent has the structural formula:

[0009]

[0010] Its elemental analysis data are: C, 54.53; H, 4.29; N, 4.37; O, 10.11; S, 6.14; Eu, 9.62; its gel permeation chromatography analysis obtained a polydispersity index Mw / Mn of 1.23, wherein Mw is the weight average molecular weight and Mn is the number average molecular weight.

[0011] In one embodiment, the number average molecular weight Mn of the light conversion agent is 6000-6800, the molar ratio of the Eu complex to the rhodamine B derivative in the light conversion agent is 1:1, and the degree of polymerization n of the light conversion agent is 4.

[0012] The present application also provides a method for preparing the above-mentioned light conversion agent, comprising the following steps:

[0013] S1, synthesis of 5-acrylamido-1,10-phenanthroline;

[0014] S2, dissolving europium chloride hexahydrate and distilled water to form a europium chloride solution, heating the europium chloride solution to a certain temperature, and adding 2-thenoyltrifluoroacetone, 5-acrylamide-1,10-phenanthroline synthesized in S1 and anhydrous ethanol solution to the europium chloride solution, maintaining the temperature of the mixed solution and stirring it uniformly at the temperature for a period of time to completely precipitate the precipitate, washing and filtering the precipitate with distilled water and anhydrous ethanol solution, and drying it in a vacuum oven at a certain temperature for a period of time to synthesize a Eu complex;

[0015] S3, adding rhodamine B to a container, and then adding N,N-dimethylformamide, propylene bromide and cesium carbonate to the container in sequence, stirring at a certain temperature for a period of time, concentrating the filtrate after the reaction in the container is completed, dissolving the concentrated filtrate in dichloromethane to filter the cesium carbonate, dissolving the filtrate in a small amount of methanol, and after shaking, pouring the solution into ether to precipitate the product, separating the product by decantation and drying it in a vacuum drying oven at a certain temperature to synthesize a rhodamine B derivative;

[0016] S4, dissolving the mixture of the rhodamine B derivative synthesized in step S3, the Eu complex synthesized in step S2 and azobisisobutyronitrile in a dried tetrahydrofuran solution solvent in a container to form a ligand solution, purging the ligand solution evenly with argon for a period of minutes, and sealing it under a reducing argon atmosphere, continuously stirring the ligand for a period of time at a certain temperature to copolymerize the ligand solution, after the reaction is completed, diluting the viscous solution with a certain amount of tetrahydrofuran solution, and precipitating it into a certain amount of methanol under vigorous stirring, filtering, collecting the obtained copolymer product and drying it under reduced pressure, and the copolymer product is successively purified for a period of time and vacuum dried for a period of time to synthesize the light conversion agent.

[0017] In one embodiment, step S1 specifically comprises: stirring a suspension of acetonitrile mixed with 5-amino-1,10-phenanthroline at room temperature and an argon atmosphere, sequentially adding triethylamine, acryloyl chloride and acetonitrile reagents to the suspension, allowing the suspension to react for a period of time, concentrating the suspension under reduced pressure to obtain a residue, performing chromatographic separation on the residue using an eluent made of chloroform and ethanol, removing the solvent from the residue, and synthesizing 5-acrylamide-1,10-phenanthroline.

[0018] In one embodiment, in step S4, the components in the ligand solution are as follows: 9 mM of rhodamine B derivative and 9 mM of Eu complex in terms of molar content; 0.5 wt % of azobisisobutyronitrile; 40 ml of dried tetrahydrofuran solution solvent and 50 ml of methanol.

[0019] This embodiment provides a light conversion film, including the light conversion agent and a polymer matrix.

[0020] In one embodiment, the polymer matrix is ​​polylactic acid.

[0021] Compared with the prior art, this application has at least the following beneficial effects:

[0022] The light conversion agent in the present application is a europium complex copolymer synthesized by free radical copolymerization of Eu complex and rhodamine B derivative, the Eu complex has a double bond structure exposed outside the 5-amino-1,10-phenanthroline molecule, and the structure of the rhodamine B derivative is that the carboxyl position of rhodamine B is connected to a double bond structure exposed outside the molecule, in the copolymer, the Eu complex partially retains the ultraviolet absorption and red light emission capabilities of the organic rare earth complex, and the rhodamine B derivative can transfer the energy of the yellow-green light part to the luminescent object of the organic rare earth complex, thereby converting the yellow-green light into red light. Therefore, the light conversion agent and light conversion film in the present application can not only convert ultraviolet light into red light, but also convert the strong yellow-green light in visible light into red light, thereby improving the utilization rate of sunlight in the photosynthetic process of plants.

[0023] The light conversion agent in the present application has good compatibility with the polymer matrix, and the light conversion film in the present application has better luminous performance, stability and mechanical properties. The service life of the light conversion film in the present application is longer than that of the light conversion film in the prior art. The polymer matrix of the light conversion film in the present application is polylactic acid, which is an environmentally friendly material that is insoluble in water, and reduces its pollution to the environment while ensuring the performance of the light conversion film. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a roadmap for the chemical synthesis of light conversion agents from Eu complexes and rhodamine B derivatives;

[0025] Figure 2 This is a physical picture of different light conversion agents;

[0026] Figure 3 It is the best excitation emission diagram of the light transfer agent in this application;

[0027] Figure 4 is the emission diagram of the light transfer agent in the present application in the ultraviolet region;

[0028] Figure 5 This is a physical picture of different light-converting films;

[0029] Figure 6 This is a comparison chart of UV absorption of different light conversion films;

[0030] Figure 7 This is a comparison chart of the transmission of different light-converting films;

[0031] Figure 8 It is the best excitation emission diagram of the light transfer film in this application;

[0032] Fig. 9 It is the emission diagram of the light transfer film in the ultraviolet region in this application;

[0033] Fig.10 It is the emission diagram of the light transfer film in the visible light region in this application;

[0034] Fig.11 This is a comparison chart of the conversion effect of different light conversion films on xenon lamp light source;

[0035] Fig.12 This is a comparison chart of the conversion effects of different light conversion films on the solar spectrum;

[0036] Fig.13 This is a comparison chart of the mobility of different light conversion films;

[0037] Fig.14 This is a test diagram of the stability of the light conversion film of this application;

[0038] Fig.15 This is a test chart of the stability of PLA-A light-converting film;

[0039] Fig.16 This is a test chart of the stability of PLA-C light-converting film;

[0040] Fig.17 It is a comparison diagram of the surface (abc) and cross section (def) of different light conversion films;

[0041] Fig.18 This is a comparison table of the mechanical properties of different light-converting films;

[0042] Fig.19 This is a comparison chart of the planting effects of lettuce grown using different light-converting films;

[0043] Fig. 20 This is a comparison chart of the growth rate of lettuce grown using different light conversion films with a 20cm ruler as a reference;

[0044] Fig.21 It is a line graph showing the effect of different light conversion films on the growth rate of lettuce;

[0045] FIG22( a ) is a comparison of the effects of different light conversion films on the wet weight of lettuce;

[0046] FIG22( b ) is a comparison of the effects of different light conversion films on the dry weight of lettuce;

[0047] FIG22( c ) is a comparison of the effects of different light conversion films on the number and width of lettuce leaves;

[0048] FIG22( d ) is a comparison of the effects of different light conversion films on lettuce plant height and root length;

[0049] FIG22( e ) is a comparison of the effects of different light conversion films on the soluble sugar content of lettuce;

[0050] FIG22( f ) is a comparison of the effects of different light conversion films on the soluble protein content of lettuce; DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is described below by means of specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present application.

[0052] The terms used in this disclosure are for the purpose of describing specific embodiments only and are not intended to limit the disclosure. The singular forms of "a", "said" and "the" used in this disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0053] It should be understood that although the terms first, second, third, etc. may be used in the present disclosure to describe various information, such information should not be limited to these terms and should not be understood as indicating or implying relative importance. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of the present disclosure, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0054] In the description of this application, unless otherwise specified and limited, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a mechanical connection or the internal connection between two components. It can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances.

[0055] In order to better understand the technical solution of the present application, the present application is described in detail below with reference to the accompanying drawings.

[0056] A light conversion agent for light conversion film, the light conversion agent is a europium complex copolymer synthesized by free radical copolymerization of Eu complex and rhodamine B derivative, the Eu complex has a double bond structure exposed outside the 5-amino-1,10-phenanthroline molecule, and the double bond position exposed outside the molecule of the Eu complex structure is connected by amino group and acryloyl chloride through substitution reaction; the structure of the rhodamine B derivative is a double bond structure exposed outside the molecule connected to the carboxyl position of rhodamine B, and the rhodamine B derivative is prepared by substitution reaction of rhodamine B and allyl bromide. Among them, the general molecular formula of the structure of the Eu complex is Eu(TTA)3(Aphen), TTA is 2-thenoyltrifluoroacetone, Aphen is 5-acrylamide-1,10-phenanthroline, and the chemical synthesis of the Eu complex and the rhodamine B derivative is as follows: Figure 1 In this application, the Eu complex containing a double bond structure is referred to as LCA-A, the rhodamine B derivative is referred to as RB-D, and the photoconverter is referred to as P Eu .

[0057] The structural formula of the light conversion agent is:

[0058]

[0059] Its elemental analysis data is Anal.Found.for P Eu:C, 54.53;H, 4.29;N, 4.37;O, 10.11;S, 6.14;Eu, 9.62. The polydispersity index Mw / Mn of the light conversion agent obtained by gel permeation chromatography (GPC) analysis is 1.23, wherein Mw is the weight average molecular weight, Mn is the number average molecular weight, the number average molecular weight is Mn is 6000-6800, and Mn is 6200 in this embodiment. The molar ratio of Eu complex to rhodamine B derivative in the light conversion agent is 1:1, and the polymerization degree n of the light conversion agent is 4.

[0060] The present invention introduces a rhodamine B derivative having yellow-green light absorption capability into an organic rare earth complex to form a europium complex luminescent copolymer, in which the organic rare earth complex partially retains its ultraviolet absorption and red light emission (λ em =615nm; 5 D0- 7 F2) ability. The organic rare earth complex and the rhodamine B derivative partially construct an appropriate guest-host system, and realize effective intramolecular energy transfer in the form of a polymer. The rhodamine B derivative acts as a receiving antenna for the yellow-green light energy in the system, and is used as an effective energy donor and hole transport material to transfer the energy of the yellow-green light part to the organic rare earth complex luminescent guest, thereby achieving the purpose of converting the yellow-green light into red light.

[0061] The present invention also provides a method for preparing the light conversion agent, comprising the following steps:

[0062] S1. Synthesis of 5-acrylamide-1,10-phenanthroline.

[0063] At room temperature and an argon atmosphere, a suspension of 5-amino-1,10-phenanthroline in acetonitrile was stirred and mixed, wherein 5-amino-1,10-phenanthroline was (Mr: 195.22) (0.98 g, 5.0 mmol), and the suspension of acetonitrile was 20 mL. 2 mL of triethylamine, 1.5 mL of acryloyl chloride and 15 mL of acetonitrile reagent were sequentially added dropwise to the suspension. After the suspension was allowed to react for 24 hours, the suspension was concentrated under reduced pressure to obtain a residue. The residue was chromatographed on a silica gel column with an eluent made of chloroform and ethanol to remove the solvent from the residue to obtain 0.72 g of yellow crystals, which contained 5-acrylamide-1,10-phenanthroline.

[0064] The volume ratio of chloroform to ethanol in the eluent is 9:1. 5-acrylamide-1,10-phenanthroline is referred to as AMP in the present application. The yield of the obtained AMP is 73.2%.

[0065] The high-resolution mass spectrometry (HRMS) data of the AMP synthesized in this step is: 15 H 11 N3O]249.0900; found[M+H] + 250.0000. H Nuclear Magnetic Resonance Spectra (1H NMR) data: δ9.27 (tt, J = 7.4, 3.7 Hz, 2H), 8.46-8.38 (m, 1H), 8.27 (dd, J = 8.1, 1.8 Hz, 1H), 8.11 (dd, J = 8.3, 1.7 Hz, 1H), 7.78-7.66 (m, 2H), 7.56 (s, 1H), 6.65-6.50 (m, 2H), 5.79 (dd, J = 8.6, 3.3 Hz, 1H). .

[0066] S2. Synthesize Eu complex.

[0067] 0.18 g of 0.5 mM europium chloride hexahydrate EuCl3·6H2O was placed in a 50 ml round-bottom flask and dissolved with 20 ml of distilled water. The EuCl3 solution was heated to 60°C on a magnetic stirrer, and an appropriate amount of anhydrous ethanol solution of 0.33 g of 1.5 mM TTA and 0.12 g of 0.5 mM AMP was added to the EuCl3 solution. The mixed solution was uniformly stirred at 60°C for 3 hours to completely precipitate the precipitate. The precipitate was washed and filtered with distilled water and anhydrous ethanol, and dried in a vacuum oven at 60°C for 12 hours to obtain 0.52 g of light yellow solid powder, which was the Eu complex.

[0068] The mass content of LCA-A in the light yellow solid powder is 81.3%. The high-resolution mass spectrometry (HRMS) data of LCA-A synthesized in this step is: calcd for [C 39 H 23 EuF9N3O7S3]1064.7600; found[M-5H] 5- 1059.8626. The organic element analysis results are Anal.Calcd.forC 39 H 23EuF9N3O7S3: C, 43.99; H, 2.18; N, 3.95; O, 10.52; S, 9.03; Eu, 14.27; found: C, 43.88;

[0069] S3. Synthesis of rhodamine B derivatives.

[0070] At room temperature and nitrogen atmosphere, 0.96 g of 2 mM rhodamine B was added to a 100 ml round-bottom flask, and then 20 ml of N, N-dimethylformamide, 1.33 g of propylene bromide, and 0.65 g of cesium carbonate were added to the round-bottom flask in sequence, and stirred at 80 ° C for 48 hours. After the reaction was completed, the filtrate was concentrated, and the concentrated filtrate was dissolved in dichloromethane to filter cesium carbonate. The filtrate was dissolved in a small amount of methanol, and after shaking, the solution was poured into ether to precipitate the product. The product was separated by decantation and dried in a vacuum drying oven at 60 ° C to synthesize 0.81 g of rhodamine B derivative product.

[0071] The yield of the rhodamine B derivative obtained in this step was 84.5%. The HRMS data of the RB-D synthesized in this step were as follows: calcd for [C 31 H 35 N2O3] + 483.2600; found [M] + 483.2644. The organic element analysis results are Anal.Calcd.for C 31 H 35 N2O3: C, 76.99; H, 7.29; N, 5.79; O, 9.92; found: C, 76.96; H, 7.3; N, 5.82; O, 9.87.

[0072] S4. Synthetic light conversion agent.

[0073] A mixture of 0.43 g of 9 mM rhodamine B derivative, 0.96 g of Eu(TTA)3(Aphen) and 0.007 g of azobisisobutyronitrile (AIBN) solid was dissolved in 40 ml of dry tetrahydrofuran (THF) solvent in a glass polymerization tube to form a ligand solution, the uniform solution was purged with argon for 5 minutes, and sealed under a reducing argon atmosphere, and the ligand solution was continuously stirred at 60°C for 72 hours for copolymerization. After the reaction was completed, the viscous solution was diluted with 5 mL of THF and precipitated into 50 mL of methanol under vigorous stirring, the obtained solid material was collected by filtration and dried under reduced pressure to obtain a copolymer product, the copolymer product was further purified by Soxhlet extraction with boiling acetone for 48 hours, and finally the copolymer product was dried in a vacuum oven at 40°C for 24 hours to synthesize 0.85 g of europium polymer product, which was a light conversion agent.

[0074] The weight percentage of AIBN solid used is 0.5, and the yield of the light conversion agent obtained in this step is 61.2%. The elemental analysis data of the light conversion agent synthesized in this step are Anal.Found.for P Eu :C, 54.53; H, 4.29; N, 4.37; O, 10.11; S, 6.14; Eu, 9.62. The polydispersity index Mw / Mn of the light conversion agent obtained by gel permeation chromatography (GPC) analysis is 1.23, where Mw is the weight average molecular weight, Mn is the number average molecular weight, and the number average molecular weight is Mn is 6000-6800. The molar ratio of the Eu complex to the rhodamine B derivative in the light conversion agent is 1:1, and the polymerization degree n of the light conversion agent is 4.

[0075] The present invention also provides a light-converting film, comprising the above-mentioned light-converting agent and a polymer matrix, in which the polymer matrix is ​​polylactic acid in this embodiment. The light-converting film containing the light-converting agent of the present application can absorb the energy of the two bands of ultraviolet light and yellow-green light in a targeted manner, thereby maximizing the increase of the red light component in the plant spectrum, and the effect in the plant planting experiment is better than the traditional light-converting film that only has ultraviolet band absorption. The polymer matrix of the present application is polylactic acid, which is a water-insoluble and environmentally friendly material, which solves the technical problems of the prior art that the light-converting film with polyethylene as the matrix is ​​difficult to degrade and pollutes the environment, and also solves the technical problems that the light-converting film with carboxymethyl cellulose as the matrix is ​​easily soluble in water and has a short service life.

[0076] The light conversion agent of the present invention realizes a free radical copolymerization reaction by exposing the double bond (Eu complex and rhodamine B derivative) structure outside the two molecules, connecting the two ligands to form a polymer structure. Among them, two molecules connected to the same polymer chain are more likely to achieve effective and Dexter energy transfer, thereby utilizing the energy of yellow-green light. In addition, the polymer structure has excellent compatibility with the polymer substrate, which can solve the serious defect problem of the light-converting film in the prior art caused by the poor compatibility between the light-converting agent and the polymer substrate.

[0077] The following are the light conversion agents in the prior art, namely the traditional europium complex LCA-C, the light conversion agent LCA-A containing a double bond structure of the Eu complex, and the light conversion agent P obtained by free radical copolymerization of the Eu complex (LCA-A) and the rhodamine B derivative (RB-D) in the present application. Eu To illustrate the P Eu Capable of converting ultraviolet light and yellow-green light into red light.

[0078] like Figure 2 As shown in the figure, from the luminescence of different light conversion agents under different illumination, it can be seen that LCA-C, LCA-A and P Eu All of them can emit red light under the irradiation of ultraviolet light with a wavelength of 365nm, indicating that the three light conversion agents can convert ultraviolet light into red light required for plant growth; LCA-C, LCA-A and P Eu Under 450nm blue light irradiation, all of them emit blue light, indicating that the three light conversion agents cannot convert blue light; LCA-C and LCA-A both emit orange light under 600nm orange light irradiation, indicating that the two light conversion agents cannot convert orange light; P Eu Under 600nm orange light, red light was emitted, indicating that the light conversion agent can convert orange light; under 525nm green light, LCA-C and LCA-A emitted green light, P Eu The red light is emitted, indicating that both LCA-C and LCA-A cannot convert green light. Eu It can convert green light into red light needed by plants; similarly, under 580nm yellow light, LCA-C and LCA-A emit yellow light, P Eu Red light is emitted, indicating that neither LCA-C nor LCA-A can convert yellow light. Eu It can convert yellow light into red light needed by plants.

[0079] Figure 3 Shows P Eu The best excitation state is: it can emit orange-red light with a wavelength of 603nm under the excitation of yellow-green light with a wavelength of 567nm. Figure 4 Shows P Eu It can also emit 615nm red light under the excitation of ultraviolet light. Figure 3 and Figure 4 Once again, it was proved that P Eu Capable of converting ultraviolet light and yellow-green light into red light.

[0080] The following are films made entirely of polylactic acid (hereinafter replaced by PLA), light-converting films made of polylactic acid and a traditional europium complex (hereinafter replaced by PLA-C), light-converting films made of polylactic acid and a Eu complex containing a double bond structure (hereinafter replaced by PLA-A), and light-converting films made of polylactic acid and the light-converting agent in the present application (hereinafter replaced by PLA-P Eu Instead of) to illustrate the PLA-P Eu Capable of converting ultraviolet light and yellow-green light into red light.

[0081] The process of preparing different membranes is as follows: four portions of 20 g of polylactic acid solid were taken respectively, and the four portions of polylactic acid solid were fully dissolved in 80 ml of dichloromethane to form polylactic acid solutions, and 5 wt% of LCA-C, LCA-A and P were added to three portions of the polylactic acid solutions respectively. Eu The three mixed solutions and the polylactic acid solution were poured into a fully automatic coating machine (model XD-TM-320 purchased from Beijing Xingde Precision Instrument Co., Ltd.) for film coating (parameter settings: speed 20 cm / min, temperature 50°C, coating thickness 100 μm) to obtain polylactic acid films PLA, PLA-C, PLA-A and PLA-P Eu .

[0082] Figure 5 From left to right in each picture are PLA, PLA-C, PLA-A and PLA-P Eu， From the luminescence of different light-converting films under different illumination, we can see that PLA-C, PLA-A and PLA-P Eu All of them can emit red light under ultraviolet light with a wavelength of 365nm, indicating that the three light conversion films can convert ultraviolet light into red light required for plant growth; PLA, PLA-C, PLA-A and PLA-P Eu Under 450nm blue light, all of them emitted blue light, indicating that none of the four films could convert blue light; under 600nm orange light, PLA, PLA-C and PLA-A all emitted orange light, indicating that none of the three films could convert orange light; PLA-P Eu Under 600nm orange light, weak red light was emitted, indicating that the film can convert part of the orange light, which is a non-main conversion area; under 525nm green light, PLA, PLA-C and PLA-A emitted green light, and PLA- emitted red light, indicating that PLA, PLA-C and PLA-A cannot convert green light, and PLA- Eu It can convert green light into red light needed by plants; similarly, under 580nm yellow light, only PLA-P Eu Red light indicates only PLA-P Eu It can convert yellow light into red light needed by plants.

[0083] from Figure 6 and Figure 7 It can be seen that PLA-P Eu Like PLA-C and PLA-A, it has obvious absorption of ultraviolet rays. Figure 8 Display PLA-P Eu The best excitation state is: it can emit red light with a wavelength of 624nm under the excitation of yellow-green light with a wavelength of 572nm. Fig. 9 Shows PLA-P Eu It can also emit 613nm red light under the excitation of ultraviolet light. Figure 8 and Fig. 9 Once again, it was proven that PLA-P Eu Capable of converting ultraviolet light and yellow-green light into red light. Fig.10 Shows PLA-P Eu It can emit 624nm red light under the irradiation of visible light with a wavelength of 400-610nm, especially under the irradiation of yellow-green light, it can emit high-intensity 624nm red light. Fig.11 In the ultraviolet light with a wavelength of 300-400nm, PLA-P Eu The emission intensities of PLA-C and PLA-A decreased, indicating that PLA-P Eu Like PLA-C and PLA-A, they can absorb ultraviolet light, but only PLA-P can absorb yellow-green light with a wavelength of 500-600nm. Eu The emission intensity decreased, indicating that only PLA-P Eu It can absorb yellow-green light. In the red light with a wavelength of 600-700nm, PLA-P Eu Compared with PLA-C and PLA-A, the strength of PLA-P Eu PLA-C and PLA-A can convert ultraviolet light into red light, but PLA-P Eu It can also convert yellow-green light into red light. PLA-C and PLA-A have a sharp peak at 600-700nm, which means that the full width at half maximum of the traditional light conversion film is too narrow, resulting in poor matching with the absorption spectrum of plant photosynthesis. Eu The red light emission peak has a large half-maximum full width, so the light conversion film in this application improves the matching degree between its conversion spectrum and the absorption spectrum of plant photosynthesis. Fig.12 It can be seen that PLA-P Eu The conversion of the solar spectrum by PLA-C and PLA-A is the same as that by the xenon lamp, which indicates that PLA-P Eu In practical applications, it is expected to achieve the same results as in indoor experiments.

[0084] from Fig.13 It can be seen that PLA-PEu The mobility curve of PLA is close to that of PLA, and PLA-P Eu The slope of the mobility curve of PLA-C is much smaller than that of PLA-A, indicating that PLA-P Eu The mobility of PLA is close to that of PLA without mobility, and PLA-P Eu The mobility of PLA-C is much smaller than that of PLA-A. Fig.17 In the figure, a) and d) are the surface and cross section of PLA-C, b) and e) are the surface and cross section of PLA-A, c) and f) are the surface and cross section of PLA-P. Eu Surface and cross section. Fig.13 and 17 It can be seen that PLA-P Eu The compatibility of PLA-C is much better than that of PLA-A. Figure 14-16 By comparison, PLA-P Eu The ability to maintain luminescence performance is much better than that of PLA-C and PLA-A. Therefore, PLA-P Eu The luminescence stability of PLA-P Eu The service life is longer than PLA-C and PLA-A. Fig.18 It can be seen that PLA-P Eu The mechanical properties are better than those of PLA-C and PLA-A, and even slightly better than those of PLA.

[0085] Lettuce is often chosen as a model plant due to its popularity in hydroponic production systems. Indoor lettuce film planting experiments can directly reflect the role of light conversion films in plant production. PLA, PLA-C, PLA-A and PLA-P are used below. Eu The relevant physiological indicators of lettuce after film covering were compared.

[0086] from Figure 19-21 It can be seen that PLA-P Eu Compared with PLA, PLA-C and PLA-A, PLA-P has a significant promoting effect on the growth and development of lettuce. Eu The lettuce has a higher leaf density and plant height. The plant height changes of the lettuce after film covering were tracked at intervals of 2 days to reflect the growth rate of the lettuce. Fig. 20 and Fig.21 As shown, the results show that the PLA-P Eu In the next 8 days, the plant heights of PLA, PLA-C and PLA-A were significantly higher. Eu The plant height of the lettuce in the film-covered treatment group was 1.32, 1.14, and 1.13 times that of the PLA, PLA-C, and PLA-A treatment groups, respectively.Eu It can effectively promote the growth rate of lettuce, thanks to PLA-P Eu Provides more red light for lettuce growth and development.

[0087] The determination of the biomass and nutritional quality of lettuce samples is a direct method to verify the effect of light conversion film on the growth of lettuce, so we measured the relevant physiological indicators of lettuce 20 days after film covering. The results showed that Fig.22a As shown, compared with PLA, PLA-P Eu , PLA-C and PLA-A can significantly (p<0.05) increase the fresh weight of the aboveground part of lettuce by 72.22%, 39.58% and 40.97%, and the fresh weight of the underground part by 94.12%, 67.65% and 70.59%, respectively. The effect of film covering on the dry weight of lettuce is similar to that on the fresh weight, increasing by 76.88%, 42.59% and 44.11% in the aboveground part and 108.79%, 75.23% and 80.65% in the underground part, respectively. Figure 22b In addition, the plant height (22.76%, 11.22% and 14.39%), root length (37.00%, 13.22% and 15.99%) ( Fig.22d ), leaf number (73.56%, 43.84% and 46.16%) and leaf width (21.33%, 10.27% and 11.73%) ( Fig.22c As shown in the figure, PLA-P Eu The performance of PLA-P was significantly better than that of other film treatments. The soluble sugar and soluble protein content can be used as important indicators of the nutritional quality of lettuce. The test results showed that compared with PLA, PLA-P Eu , PLA-C and PLA-A film treatment groups ( Fig.22e ) increased by 43.91%, 23.65% and 25.90% (p<0.05), respectively, and the soluble protein content ( Figure 22f The results show that the Eu-complex copolymer membrane PLA-P Eu It more significantly promoted the increase of soluble sugar and soluble protein content in lettuce.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit it. Although the present application has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the application can still be modified or some technical features can be replaced by equivalents without departing from the spirit of the technical solution of the present application, which should be included in the scope of the technical solution for protection in the present application.

Claims

1. A light conversion agent for a light conversion film, characterized in that: The light conversion agent is a europium complex copolymer synthesized by free radical copolymerization of an Eu complex and a rhodamine B derivative, wherein the Eu complex has a double bond structure exposed outside the 5-amino-1,10-phenanthroline molecule, and the double bond position exposed outside the molecule of the Eu complex structure is connected by an amino group and acryloyl chloride through a substitution reaction; the structure of the rhodamine B derivative is that a double bond structure exposed outside the molecule is connected at the carboxyl position of rhodamine B, and the rhodamine B derivative is prepared by a substitution reaction between rhodamine B and allyl bromide.

2. The light conversion agent according to claim 1, characterized in that The general molecular formula of the structure of the Eu complex is Eu(TTA)3(Aphen), wherein TTA is 2-thenoyltrifluoroacetone and Aphen is 5-acrylamide-1,10-phenanthroline.

3. The light conversion agent according to claim 1, characterized in that The structural formula of the light conversion agent is: Its elemental analysis data are: C, 54.53; H, 4.29; N, 4.37; O, 10.11; S, 6.14; Eu, 9.62; its gel permeation chromatography analysis obtained a polydispersity index Mw / Mn of 1.23, wherein Mw is the weight average molecular weight and Mn is the number average molecular weight.

4. The light conversion agent according to claim 3, characterized in that The number average molecular weight Mn of the light conversion agent is 6000-6800, the molar ratio of the Eu complex to the rhodamine B derivative in the light conversion agent is 1:1, and the polymerization degree n of the light conversion agent is 4.

5. A method for preparing the light conversion agent according to claim 1, characterized in that: The following steps are involved: S1, synthesis of 5-acrylamido-1,10-phenanthroline; S2, dissolving europium chloride hexahydrate and distilled water to form a europium chloride solution, heating the europium chloride solution to a certain temperature, and adding 2-thenoyltrifluoroacetone, 5-acrylamide-1,10-phenanthroline synthesized in S1 and anhydrous ethanol solution to the europium chloride solution, maintaining the temperature of the mixed solution and stirring it uniformly at the temperature for a period of time to completely precipitate the precipitate, washing and filtering the precipitate with distilled water and anhydrous ethanol solution, and drying it in a vacuum oven to synthesize the Eu complex; S3, adding rhodamine B to a container, and then adding N,N-dimethylformamide, propylene bromide and cesium carbonate in sequence, stirring at a certain temperature for a period of time, concentrating the filtrate after the reaction in the container is completed, dissolving the concentrated filtrate in dichloromethane to filter cesium carbonate, dissolving the filtrate in a small amount of methanol, and after shaking, pouring the solution into ether to precipitate the product, separating the product by decantation and drying it in a vacuum drying oven at a certain temperature to synthesize a rhodamine B derivative; S4, dissolving a mixture of the rhodamine B derivative synthesized in step S3, the Eu complex synthesized in step S2 and azobisisobutyronitrile in a container filled with dried tetrahydrofuran solvent to form a ligand solution, purging the ligand solution with argon for a period of time, and sealing it under a reducing argon atmosphere, continuously stirring the ligand for a period of time at a certain temperature to copolymerize the ligand solution, after the reaction is completed, diluting the viscous solution with a certain amount of tetrahydrofuran solution, and precipitating it into a certain amount of methanol under vigorous stirring, filtering, collecting the obtained solid material and drying it under reduced pressure, and the copolymer product is successively purified for a period of time and vacuum dried to synthesize the light conversion agent.

6. The method for preparing a light conversion agent according to claim 5, characterized in that: Step S1 specifically comprises: stirring a suspension of acetonitrile mixed with 5-amino-1,10-phenanthroline at room temperature and an argon atmosphere, sequentially adding triethylamine, acryloyl chloride and acetonitrile reagents to the suspension, allowing the suspension to react for a period of time, concentrating the suspension under reduced pressure to obtain a residue, performing chromatographic separation on the residue using an eluent made of chloroform and ethanol, removing the solvent in the residue, and synthesizing 5-acrylamide-1,10-phenanthroline.

7. The method for preparing a light conversion agent according to claim 5, characterized in that: In step S4, the components of the ligand solution are as follows: 9 mM of rhodamine B derivative and 9 mM of Eu complex in terms of molar content; 0.5 wt % of azobisisobutyronitrile; 40 ml of dried tetrahydrofuran solvent and 50 ml of methanol.

8. A light conversion film, characterized in that: The method comprises the light conversion agent as described in claims 1 to 4 and a polymer matrix.

9. The light-converting film according to claim 8, characterized in that: The polymer matrix is ​​polylactic acid.

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