Down-conversion material for converting ultraviolet light into visible light as well as preparation method and application of down-conversion material

Abstract

The invention relates to the technical field of organic synthesis and new energy photovoltaic, and discloses a down-conversion material for converting ultraviolet light in sunlight into visible light, a preparation method of the down-conversion material and application of the down-conversion material in preparation of a light conversion film material, the down-conversion material is characterized in that the structure of the down-conversion material is shown as a formula III: # imgabs0 #, and R2 is-CHO,-CN,-Cl,-F,-Ph,-H,-Me,-tBu and-OMe.

Description

Technical field:

[0001] The present invention relates to the field of organic synthesis and new energy photovoltaic technology, and in particular to a down-conversion material for converting ultraviolet light into visible light, and a preparation method and application thereof. Background technology:

[0002] A solar cell is a photoelectric conversion device that converts the photon energy of sunlight into electrical energy through the photovoltaic effect. The spectral range of sunlight covers multiple electromagnetic wave bands, with wavelengths ranging from 10nm to 1mm. The second-generation solar cells (i.e., thin-film solar cells) have shown broad application prospects in market segments such as portable photovoltaic devices and flexible applications due to their high material utilization, low manufacturing cost, and flexible application characteristics. However, the current utilization efficiency of thin-film solar cells in the sunlight band is relatively low, and its usable band is limited to 400nm to 850nm. In order to improve its photoelectric conversion efficiency, sunlight conversion materials can be added to the film to convert the unused bands in the sunlight into wavelengths in the range of 400nm to 850nm for utilization.

[0003] Furthermore, converting the ultraviolet light in sunlight into visible light can not only improve the photoelectric utilization rate of thin-film solar cells, but also further reduce the light damage of ultraviolet light to thin-film materials, reduce the light aging of thin films, and extend the service life of thin-film solar cells. Materials that convert short-wave ultraviolet light into long-wave visible light are down-conversion materials. Summary of the invention:

[0004] The purpose of the present invention is to provide a down-conversion material for converting ultraviolet light into visible light, and a preparation method and application thereof.

[0005] The present invention is achieved through the following technical solutions:

[0006] A down-conversion material that converts ultraviolet light in sunlight into visible light, the structure of which is shown in Formula III:

[0007]

[0008] Among them, R 2 It is CHO, CN, Cl, F, Ph, H, Me, tBu, OMe.

[0009] A UV absorber, the structure of which is shown in Formula I to Formula II:

[0010]

[0011] The method for preparing the down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III is characterized by comprising the following steps:

[0012] 1) using benzotriazole and isobutyl bromide as raw materials, preparing a benzotriazole alkylation product (including N1 and N2 alkylation products) by substitution reaction, and obtaining an N2-isobutyl substituted benzotriazole by separation and purification, the structure of which is shown in Formula I;

[0013] 2) using N2-isobutyl substituted benzotriazole as a raw material, preparing N2-isobutyl substituted benzotriazole bromide product by bromination reaction, and obtaining N2-isobutyl-4,7-dibromo substituted benzotriazole by separation and purification, the structure of which is shown in Formula II;

[0014] 3) Using N2-isobutyl-4,7-dibromo-substituted benzotriazole and different substituted phenylboronic acids as raw materials and palladium as a catalytic metal, a N2-isobutyl-substituted benzotriazole derivative shown in formula III is prepared by Suzuki coupling reaction, and the corresponding target product is obtained by separation and purification.

[0015] Step 1) specifically comprises the following steps: dissolving benzotriazole in an organic solvent (such as methanol, ethanol, dimethyl sulfoxide, N,N-dimethylaminoformamide, pyrrolidone, tetrahydrofuran, etc.), stirring and dissolving completely, and then adding a base (such as potassium carbonate, sodium carbonate, potassium phosphate, sodium hydroxide, potassium hydroxide, DBU, sodium methoxide, sodium ethoxide, etc.) thereto to obtain a benzotriazole anion; then dropping isobutyl bromide thereto to carry out a substitution reaction, controlling the temperature at 60-90° C., reacting for 2-6 hours, and preparing a crude isobutyl substituted benzotriazole; then purifying the crude isobutyl substituted benzotriazole by separation means (such as column chromatography, pulping, recrystallization, etc.) to obtain an N2-isobutyl substituted benzotriazole (product of formula I).

[0016] Preferably, the solvent used in step 1) is an aprotic high polar solvent, such as dimethyl sulfoxide or N,N-dimethylaminoformamide, and the amount of the solvent used is preferably 3-5 mL / g (calculated as benzotriazole); the base used is preferably sodium hydroxide, and the molar ratio of benzotriazole to sodium hydroxide is 1:1.0-1.5, more preferably 1:1.05-1.15; the molar ratio of benzotriazole to isobutyl bromide is preferably 1.0-1.5 equivalents, more preferably 1 .05-1.15; the reaction temperature of isobutane bromide and benzotriazole anion is preferably 70-80°C, and the reaction time is preferably 2-3 hours; the crude reaction product can be cooled and filtered to perform preliminary separation and purification to remove N1-isobutyl substituted benzotriazole to obtain N2-isobutyl substituted benzotriazole oil, and then further purified by column chromatography, the elution condition is PE:EA=20:1, to obtain pure N2-isobutyl substituted benzotriazole.

[0017] Step 2) The specific steps are: dissolving N2-isobutyl substituted benzotriazole in an organic solvent (such as methanol, ethanol, dimethyl sulfoxide, N,N-dimethylaminoformamide, acetic acid, n-hexane, acetonitrile, tetrahydrofuran, etc.), stirring and dissolving completely, adding a bromination reagent (such as hydrobromic acid-bromine, NBS) and a bromination catalyst thereto, and carrying out a bromination reaction. According to different bromination reaction conditions, the reaction temperature is controlled to be between 60-130° C., and the reaction is carried out for 8-12 hours to obtain a crude product of N2-isobutyl-4,7-dibromosubstituted benzotriazole, which is purified by recrystallization and column chromatography.

[0018] Preferably, the organic solvent used in step 2) is a polar solvent, such as acetonitrile or acetic acid, and the amount of the solvent used is preferably 2-5 mL / g (calculated based on N2-isobutyl substituted benzotriazole); the bromination reagent is preferably NBS, and the amount of NBS is preferably 2-4 equivalents, more preferably 2.5-3 equivalents; the catalyst is preferably a free radical initiator, such as BPO, AIBN, TBP, BCP, LBO, etc., more preferably AIBN with a decomposition temperature of about 80°C, and the amount of the catalyst is preferably 0.05-0.1wt%; NBS is used as the bromination reagent for the bromination reaction, the temperature is preferably 70-80°C, the reaction time is preferably 10-12 hours, and the crude product of N2-isobutyl-4,7-dibromo-substituted benzotriazole is obtained, and then the crude product is purified by recrystallization from petroleum ether and purified by column chromatography, and the elution condition is PE:EA=20:1 to obtain pure N2-isobutyl-4,7-dibromo-substituted benzotriazole.

[0019] Step 3) specifically comprises the following steps: dissolving N2-isobutyl-4,7-dibromo-substituted benzotriazole and phenylboronic acid of different substitutions in an organic solvent (such as methanol, ethanol, toluene, acetonitrile, tetrahydrofuran or a mixed solvent thereof), then adding a base (such as potassium carbonate, sodium carbonate, potassium phosphate, sodium hydroxide, etc.), adding a Suzuki coupling catalyst (such as (tetrakis(triphenylphosphine)palladium), (dichlorobis(triphenylphosphine)palladium), (palladium acetate), (bis(η4-styryl ketone)tripalladium), (dichlorobis(triphenylphosphine)nickel), etc.) under nitrogen protection, controlling the reaction temperature between 60-100° C., reacting for 4-8 hours, obtaining a crude N2-isobutyl-substituted benzotriazole derivative, and performing post-treatment to obtain the corresponding product.

[0020] Preferably, the reaction solvent in step 3) is a non-protonic solvent miscible with water, such as acetonitrile or tetrahydrofuran, and the amount of the solvent used is preferably 2-5 mL / g (calculated based on the total amount of reactants); the molar ratio of N2-isobutyl-4,7-dibromo-substituted benzotriazole to phenylboric acid is preferably 1:2-3, more preferably 1:2.2-2.4; the base used in the reaction is preferably potassium carbonate or sodium carbonate, and the amount of the base is preferably 2.0-3.0 equivalents; the catalyst is preferably a zero-valent palladium complex, such as (tetrakis(triphenylphosphine)palladium), and the amount is 0.05-0.5wt% (calculated based on N2-isobutyl-4,7-dibromo-substituted benzotriazole); the reaction temperature is preferably 75-85°C, and the reaction is performed for 4-6 hours; after obtaining the N2-isobutyl-substituted benzotriazole derivative, the solvent is removed, and then purified by column chromatography, and the elution condition is PE:EA=10:1 to obtain the corresponding pure product.

[0021] The present invention also protects the application of the materials shown in Formula I to Formula III in the preparation of light-converting film materials. The film materials are made of polyvinyl alcohol (PVA), polymethyl methacrylate (PMMA) and the like.

[0022] The beneficial effects of the present invention are as follows:

[0023] 1) The compounds of the present invention can improve the absorption efficiency of materials for light of specific wavelengths, enhance the energy transfer process, and improve the light conversion efficiency by optimizing the matching of absorption and emission spectra. They provide adjustable light conversion materials for the fields of agriculture, photovoltaics, display technology, etc., such as agricultural films: they can absorb ultraviolet or blue light and convert it into red light that is more conducive to plant photosynthesis, thereby increasing crop yields; solar photovoltaic films: they optimize the light absorption range and improve the utilization efficiency of solar cells; and display and lighting: they regulate the spectral characteristics and improve the color purity and stability of luminescent materials.

[0024] 2) The preparation method of the present invention adjusts the structure of the derivative product by changing the type of phenylboronic acid used, and then adjusts the characteristics of its absorption / emission spectrum, including the maximum absorption wavelength, emission wavelength, Stokes shift, half-peak width, etc., to achieve fundamental adjustment of light conversion performance. This regulation method is simpler, more efficient and more flexible than traditional molecular structure modification, avoids complex synthesis steps, and improves experimental feasibility. Description of the drawings:

[0025] Figure 1 is the H NMR spectrum of the product prepared in Example 3 of the present invention;

[0026] Figure 2 is the H NMR spectrum of the product prepared in Example 5 of the present invention;

[0027] Figure 3 is the H NMR spectrum of the product prepared in Example 7 of the present invention;

[0028] Figure 4 is the H NMR spectrum of the product prepared in Example 9 of the present invention;

[0029] Figure 5 is the UV-visible absorption spectrum corresponding to the product prepared in Example 1;

[0030] Figure 6 is the UV-visible absorption spectrum corresponding to the product prepared in Example 2;

[0031] Figure 7 It is the ultraviolet-visible light absorption spectrum and fluorescence emission spectrum of the product prepared in Example 3 of the present invention;

[0032] Figure 8 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the product prepared in Example 4 of the present invention;

[0033] Fig. 9 It is the ultraviolet-visible light absorption spectrum and fluorescence emission spectrum of the product prepared in Example 5 of the present invention;

[0034] Fig.10 It is the ultraviolet-visible light absorption spectrum and fluorescence emission spectrum of the product prepared in Example 6 of the present invention;

[0035] Fig.11 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the product prepared in Example 7 of the present invention;

[0036] Fig.12 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the product prepared in Example 8 of the present invention;

[0037] Fig.13 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the product prepared in Example 9 of the present invention;

[0038] Fig.14 It is the ultraviolet-visible light absorption spectrum and fluorescence emission spectrum of the product prepared in Example 10 of the present invention;

[0039] Fig.15 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the product prepared in Example 11 of the present invention;

[0040] Fig.16 This is a diagram showing the application effect of the product prepared in Application Example 1 of the present invention in PVA;

[0041] Fig.17 This is a diagram showing the application effect of the product prepared in Application Example 2 of the present invention in PVA;

[0042] Fig.18 This is a diagram showing the application effect of the product prepared in Application Example 2 of the present invention in PVA;

[0043] Fig.19 This is a diagram showing the application effect of the product prepared in Application Example 3 of the present invention in PMMA;

[0044] Fig. 20 This is a diagram showing the application effect of the product prepared in Application Example 4 of the present invention in PMMA. Specific implementation method:

[0045] The following is a further description of the present invention, rather than a limitation of the present invention.

[0046] Example 1: Preparation of N2-isobutyl substituted benzotriazole (Formula I)

[0047] The steps include:

[0048] 1. Add 500 mL of dimethyl sulfoxide to a 1L three-necked flask, then add 119 g of benzotriazole and 44 g of sodium hydroxide in sequence, turn on the mechanical stirring, set the speed to 300 RPM, stir and dissolve the raw materials, and control the solution temperature below 80°C; after the solid is completely dissolved by stirring, control the internal temperature between 70-80°C, add 157 g of isobutyl bromide dropwise, control the dropping speed, and complete the dropwise addition within 1.0 hour; after the dropwise addition of isobutyl bromide is completed, maintain the temperature, continue the reaction for 1.5 hours, and then stop the reaction;

[0049] 2. After the reaction is completed, stop heating, add 300 mL of deionized water, stir for 5 minutes and then stand to separate the layers, remove the water layer to obtain an organic layer solution; cool it naturally to room temperature and place it in a freezer for 12 hours, filter it and obtain a crude yellow oil. The crude product is purified by column chromatography, eluting with PE:EA=20:1 to obtain 52 g of pure N2-isobutyl substituted benzotriazole, with a yield of 30%.

[0050] The product was dissolved in dichloromethane to prepare a 10 ppm solution, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Figure 5 As shown, there is no fluorescence.

[0051] Example 2: Preparation of N2-isobutyl-4,7-dibromosubstituted benzotriazole (Formula II)

[0052] The steps include:

[0053] 1. Add 700 mL of acetic acid, 175 g of N2-isobutyl substituted benzotriazole, 445 g of N-bromosuccinimide (NBS), and 0.1 g of AIBN into a 2L three-necked flask, start mechanical stirring, set the speed to 400 RPM, stir and break up the raw materials, start heating, maintain the reaction liquid temperature at 75-78 ° C, stir and react for 10 hours, and then stop the reaction;

[0054] 2. After the reaction is completed, add 800 mL of deionized water, stir for 5 minutes and then stand to separate the layers to obtain an organic layer solution; add 200 mL of petroleum ether, cool naturally to room temperature and place it in a freezer for 12 hours, filter and obtain a brown solid crude product. The crude product is purified by column chromatography, eluting with PE:EA=20:1 to obtain 133 g of pure N2-isobutyl-4,7-dibromosubstituted benzotriazole, with a yield of 40%.

[0055] The product was dissolved in dichloromethane to prepare a 10 ppm solution, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Figure 6 As shown, there is no fluorescence.

[0056] Example 3: 2-isobutyl-4,7-diphenyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light, represented by Formula III, wherein R 2 Preparation method of -H)

[0057] The steps include:

[0058] 1. Add 3.3 g of N2-isobutyl-4,7-dibromo-substituted benzotriazole, 3.5 g of potassium carbonate, 3.0 g of phenylboric acid, and then add 15 mL of toluene, 15 mL of ethanol and 15 mL of deionized water into a 100 mL three-necked flask, start mechanical stirring, set the speed to 300 RPM, stir and dissolve the raw materials, start heating, control the internal temperature to 75°C, and start nitrogen blowing to protect the inert gas environment of the reaction system; after blowing for 30 minutes, add 0.01 g of tetrakis(triphenylphosphine)palladium, maintain the temperature at 78°C and continue the reaction for 5 hours, then stop the reaction;

[0059] 2. After the reaction was completed, 30 mL of deionized water was added, stirred for 5 minutes, and then allowed to stand to separate to obtain an organic layer solution; after evaporating the solution to dryness, a crude product was obtained, which was purified by column chromatography with PE:EA=10:1 as eluent to obtain 2.9 g of pure 2-isobutyl-4,7-diphenyl-2H-benzo[d][1,2,3]triazole with a yield of 90%. The product H NMR spectrum data are as follows (original data as shown in Figure 1 ): 1 HNMR(500MHz,Chloroform-d)δ8.11–8.03(m,4H),7.64(s,2H),7.53(t,J=7.7Hz,4H),7.4 5–7.38(m,2H),4.61(d,J=7.3Hz,2H),2.61(dt,J=13.7,6.9Hz,1H),1.02(d,J=6.7Hz,6H).

[0060] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Figure 7 , its maximum absorption wavelength is 330nm and its emission wavelength is 407nm.

[0061] Example 4: 4,7-bis(4-methylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of -Me)

[0062] Referring to Example 3, phenylboronic acid was replaced with 3.4 g of 4-methylphenylboronic acid to obtain 3.3 g of product with a yield of 92%. The product H NMR spectrum data are as follows: 1 H NMR(500MHz,Chloroform-d)δ7.99–7.92(m,4H),7.59(s,2H),7.33(d,J=7.9Hz,4H),4 .59(d,J=7.4Hz,2H),2.60(dt,J=13.7,6.9Hz,1H),2.43(s,6H),1.00(d,J=6.7Hz,6H).

[0063] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Figure 8 , its maximum absorption wavelength is 337nm and its emission wavelength is 420nm.

[0064] Example 5: 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of -tBu)

[0065] Referring to Example 3, phenylboronic acid was replaced with 4.4 g of 4-tert-butylphenylboronic acid to obtain 3.7 g of product with a yield of 85%. The product H NMR spectrum data are as follows (the original data are as follows Figure 2 ): 1 H NMR(500MHz,Chloroform-d)δ8.08–7.97(m,4H),7.61(s,2H),7.57–7.52(m,4H),4.6 1(d,J=7.3Hz,2H),2.62(dt,J=13.8,6.9Hz,1H),1.39(s,18H),1.02(d,J=6.7Hz,6H).

[0066] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig. 9 , its maximum absorption wavelength is 337nm and its emission wavelength is 420nm.

[0067] Example 6: 4,7-bis(4-formylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of -CHO

[0068] Referring to Example 3, phenylboronic acid was replaced with 3.7 g of 4-formylphenylboronic acid to obtain 3.0 g of product with a yield of 80%. The H NMR spectrum data of the product are as follows: 1 H NMR(500MHz,Chloroform-d)δ10.11(s,2H),8.28(d,J=8.1Hz,4H),8.05(d,J=8.0Hz,4H) ,7.77(s,2H),4.64(d,J=7.3Hz,2H),2.62(dt,J=13.8,6.9Hz,1H),1.04(d,J=6.7Hz,7H).

[0069] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.10 , its maximum absorption wavelength is 358nm and its emission wavelength is 434nm.

[0070] Example 7: 4,7-bis(4-methoxyphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 -OMe) preparation method

[0071] Referring to Example 3, phenylboronic acid was replaced with 3.8 g of 4-methoxyphenylboronic acid to obtain 3.3 g of product with a yield of 85%. The H NMR spectrum data of the product are as follows (the original data are as follows Figure 3 ): 1 H NMR(500MHz,Chloroform-d)δ8.08–7.97(m,4H),7.56(s,2H),7.09–7.02(m,4H),4.5 9(d,J=7.3Hz,2H),3.89(s,6H),2.61(dh,J=13.7,7.0Hz,1H),1.02(d,J=6.7Hz,6H).

[0072] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.11 , its maximum absorption wavelength is 348nm and its emission wavelength is 443nm.

[0073] Example 8: 4,7-bis(4-cyanophenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of -CN)

[0074] Referring to Example 3, phenylboronic acid was replaced with 3.6 g of 4-cyanophenylboronic acid to obtain 3.2 g of product with a yield of 86%. The H NMR spectrum data of the product are as follows: 1 H NMR(500MHz,Chloroform-d)δ8.25–8.20(m,4H),7.85–7.80(m,4H),7.72(s,2 H), 4.63 (d, J = 7.3Hz, 2H), 2.61 (dt, J = 13.7, 6.9Hz, 1H), 1.03 (d, J = 6.7Hz, 6H).

[0075] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.12 , its maximum absorption wavelength is 346nm and its emission wavelength is 418nm.

[0076] Example 9: 4,7-bis(4-chlorophenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of Cl)

[0077] Referring to Example 3, phenylboronic acid was replaced with 3.9 g of 4-chlorophenylboronic acid to obtain 3.4 g of product with a yield of 87%. The product H NMR spectrum data are as follows (the original data are as follows Figure 4 ): 1 HNMR(500MHz,Chloroform-d)δ8.07–7.97(m,4H),7.60(s,2H),7.53–7.47(m,4 H), 4.60 (d, J = 7.3Hz, 2H), 2.59 (dt, J = 13.8, 6.9Hz, 1H), 1.02 (d, J = 6.8Hz, 6H).

[0078] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.13, its maximum absorption wavelength is 337nm and its emission wavelength is 413nm.

[0079] Example 10: 4,7-bis(4-fluorophenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 F) is a preparation method

[0080] Referring to Example 3, phenylboronic acid was replaced with 3.5 g of 4-fluorophenylboric acid to obtain 2.4 g of product with a yield of 65%. The H NMR spectrum data of the product are as follows: 1 H NMR(500MHz,Chloroform-d)δ8.11–7.99(m,4H),7.58(s,2H),7.25–7.18(m,4 H), 4.60 (d, J = 7.3Hz, 2H), 2.60 (dt, J = 13.7, 6.9Hz, 1H), 1.02 (d, J = 6.7Hz, 6H).

[0081] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.14 , its maximum absorption wavelength is 329nm and its emission wavelength is 410nm.

[0082] Example 11: 4,7-bis(4-phenylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole (a down-conversion material for converting ultraviolet light in sunlight into visible light as shown in Formula III, wherein R 2 Preparation method of Ph)

[0083] Referring to Example 3, phenylboronic acid was replaced with 4.9 g of 4-phenylphenylboronic acid to obtain 3.3 g of product with a yield of 70%. The H NMR spectrum data of the product are as follows: 1 H NMR(500MHz,Chloroform-d)δ8.18(d,J=8.2Hz,4H),7.77(d,J=8.1Hz,4H),7.74–7.67(m,6H),7.48(t,J=7. 6Hz, 4H), 7.38 (t, J = 7.3Hz, 2H), 4.65 (d, J = 7.4Hz, 2H), 2.65 (dt, J = 13.7, 6.8Hz, 1H), 1.05 (d, J = 6.7Hz, 6H).

[0084] The product was dissolved in dichloromethane to prepare a solution with a concentration of 10 ppm, and its ultraviolet absorption spectrum and fluorescence emission spectrum were collected. Fig.15 , its maximum absorption wavelength is 353nm and its emission wavelength is 442nm.

[0085] Application Example 1: Preparation method of 4,7-bis(4-methylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole modified PVA film

[0086] Dissolve 1.0 g of PVA masterbatch in 20 mL of deionized water, heat and stir in a 60°C water bath for 3 hours to obtain a 5 wt% PVA aqueous solution. Take 6 mL of the aqueous solution, spread it on a clean glass surface dish, place it at room temperature to evaporate for 2 hours, then transfer it to a 60°C oven and heat it for 3 hours to evaporate the solvent to obtain a PVA film;

[0087] Similarly, 1.0 g of PVA masterbatch was dissolved in 20 mL of deionized water, heated in a water bath at 60° C. and stirred for 3 hours to obtain a 5 wt% PVA aqueous solution, and then 2.5 mg of 4,7-bis(4-methylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole prepared in Example 4 was dissolved in 2 mL of tetrahydrofuran, and then the tetrahydrofuran solution was mixed into the PVA aqueous solution, and continued to heat and stir for 0.5 hours to obtain a 0.25 wt% doped 4,7-bis(4-methylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole-modified PVA film, 6 mL of the aqueous solution was spread flat on a glass surface dish, placed at room temperature for evaporation for 2 hours, and then transferred to a 60° C. oven and heated for 3 hours to volatilize the solvent to obtain a modified PVA film;

[0088] The conditions of PVA film and modified PVA film under natural light and 365nm ultraviolet light were recorded respectively:

[0089] Fig.16 Left 1, is a photo of PVA film under natural light; Fig.16 Left 2, is a photo of PVA film under 365nm UV light; Fig.16 Left 3, is a photo of the modified PVA film under natural light; Fig.16 Left 4 is a photo of the modified PVA film under 365nm ultraviolet light. It can be seen that after modification, the PVA film emits blue light under 365nm ultraviolet light, and has the ability to convert ultraviolet light into visible light, that is, it realizes the conversion of sunlight.

[0090] Application Example 2: PVA film modified by compounds represented by Formula I-Formula II

[0091] Refer to Application Example 1, except that the 4,7-bis(4-methylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole prepared in Example 4 is replaced by the compounds of Formula I to Formula II prepared in Example 1-2. The results are shown in Figure 17-18 . Fig.17Left, a photograph of a PVA film modified by the compound represented by Formula I under natural light; Fig.17 Right: a photo of a PVA film modified by the compound shown in Formula I under 365nm ultraviolet light. Fig.18 Left, a photo of the compound represented by Formula II under natural light; Fig.18 On the right is a photograph of the PVA film modified with the compound shown in Formula II under 365nm ultraviolet light. It can be seen that after being modified with the compounds shown in Formula I to Formula II, the PVA film emits blue light under 365nm ultraviolet light, but the effect is poorer than that of the compound shown in Formula III.

[0092] Application Example 3: Preparation method of 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole-modified PMMA film

[0093] Dissolve 1.0 g of PMMA masterbatch in 20 g of ethyl acetate, heat and stir in a 60°C water bath for 3 hours to obtain a 5 wt% PMMA solution. Take 6 mL of the solution, spread it on a clean glass surface dish, place it at room temperature to evaporate for 2 hours, then transfer it to a 60°C oven and heat it for 3 hours to evaporate the solvent to obtain a PMMA film;

[0094] Similarly, 1.0 g of PMMA masterbatch was dissolved in 20 g of ethyl acetate, heated in a water bath at 60° C. with stirring for 3 hours to obtain a 5 wt% PMMA solution, and then 5 mg of 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole prepared in Example 5 was dissolved in 2 mL of ethyl acetate, and then mixed into the PMMA solution, and heated and stirred for 0.5 hours to obtain a 0.5 wt% doped 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole-modified PMMA film. 6 mL of the solution was spread on a glass surface dish, placed at room temperature for evaporation for 2 hours, and then transferred to a 60° C. oven and heated for 3 hours to volatilize the solvent to obtain a modified PMMA film;

[0095] The conditions of PMMA film and modified PMMA film under natural light and 365nm ultraviolet light were recorded respectively: Fig.19 Left 1, is a photo of PMMA film under natural light; Fig.19 Left 2, is a photo of PMMA film under 365nm UV light; Fig.19 Left 3, is a photo of the modified PMMA film under natural light; Fig.19Left 4 is a photo of the modified PMMA film under 365nm ultraviolet light. It can be seen that after being modified with 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole, the PMMA film emits blue light under 365nm ultraviolet light, and has the ability to convert ultraviolet light into visible light, that is, it realizes the conversion of sunlight.

[0096] Application example 4:

[0097] Refer to Application Example 3, except that the 4,7-bis(4-tert-butylphenyl)-2-isobutyl-2H-benzo[d][1,2,3]triazole prepared in Example 5 is replaced by the products prepared in Examples 3, 6, 8 and 9. The results are shown in Fig.18 .

[0098] It can be seen that after modification of the down-conversion materials for converting ultraviolet light in sunlight into visible light prepared in Examples 3, 6, 8 and 9, the PVA film emits blue light under 365nm ultraviolet light and has the performance of converting ultraviolet light into visible light, i.e., realizing the conversion of sunlight.

[0099] The above are only preferred embodiments of the present invention. It should be noted that the above preferred implementations and application modes should not be regarded as limiting the present invention. The protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. The structure is shown in Formula III. The down-conversion material converts ultraviolet light in sunlight into visible light: in, R2 is -CHO, -CN, -Cl, -F, -Ph, -H, -Me, -tBu, -OMe.

2. Ultraviolet absorbers with structures as shown in Formula I to Formula II:

3. The method for preparing the down-conversion material of formula III for converting ultraviolet light in sunlight into visible light as claimed in claim 1, characterized in that: The steps include: 1) using benzotriazole and isobutyl bromide as raw materials, preparing benzotriazole alkylation product by substitution reaction, and obtaining N2-isobutyl substituted benzotriazole by separation and purification; 2) using N2-isobutyl substituted benzotriazole as a raw material, preparing N2-isobutyl substituted benzotriazole bromide product by bromination reaction, and obtaining N2-isobutyl-4,7-dibromo substituted benzotriazole by separation and purification; 3) Using N2-isobutyl-4,7-dibromo-substituted benzotriazole and different substituted phenylboronic acids as raw materials and palladium as a catalytic metal, a N2-isobutyl-substituted benzotriazole derivative shown in formula III is prepared by Suzuki coupling reaction, and the corresponding target product is obtained by separation and purification.

4. The method according to claim 3, characterized in that Step 1) The specific steps are: dissolving benzotriazole in an organic solvent, stirring and dissolving completely, adding a base thereto to obtain a benzotriazole anion; then dropping isobutyl bromide thereto, The substitution reaction is carried out, the temperature is controlled at 60-90° C., and the reaction is carried out for 2-6 hours to prepare a crude isobutyl substituted benzotriazole; the crude isobutyl substituted benzotriazole is then purified by separation means to obtain N2-isobutyl substituted benzotriazole.

5. The method according to claim 4, characterized in that The solvent used in step 1) is a non-protonic high polar solvent dimethyl sulfoxide or N,N-dimethylaminoformamide, and the amount of the solvent used is 3-5 mL / g calculated based on benzotriazole; the base used is sodium hydroxide, and the molar ratio of benzotriazole to sodium hydroxide is 1:1.0-1.5; the molar ratio of benzotriazole to isobutyl bromide is 1.0-1.5 equivalents; the temperature for the reaction of isobutyl bromide with benzotriazole anion is 70-80°C, and the reaction time is 2-3 hours; the crude reaction product can be cooled and filtered for preliminary separation and purification to remove N1-isobutyl substituted benzotriazole to obtain N2-isobutyl substituted benzotriazole oil, and then further purified by column chromatography, and the elution condition is PE:EA=20:1 to obtain pure N2-isobutyl substituted benzotriazole.

6. The method according to claim 5, characterized in that The molar ratio of benzotriazole to sodium hydroxide is 1:1.05-1.15; The molar ratio of benzotriazole to isobutyl bromide is 1.05-1.

15.

7. The method according to claim 3, characterized in that Step 2) The specific steps are: dissolving N2-isobutyl substituted benzotriazole in an organic solvent, stirring and dissolving completely, adding a bromination reagent and a bromination catalyst thereto, and carrying out a bromination reaction. According to different bromination reaction conditions, the reaction temperature is controlled to be between 60-130° C., and the reaction is carried out for 8-12 hours to obtain a crude product of N2-isobutyl-4,7-dibromosubstituted benzotriazole, which is purified by recrystallization and column chromatography.

8. The method according to claim 7, characterized in that The organic solvent used in step 2) is a polar solvent acetonitrile or acetic acid, and the amount of the solvent used is 2-5 mL / g calculated based on the N2-isobutyl substituted benzotriazole; the bromination reagent uses NBS, and the amount of NBS used is 2-4 equivalents; The catalyst uses free radical initiators BPO, AIBN, TBP, BCP and LBO, and the amount of the catalyst is 0.05-0.1wt%; the bromination reaction temperature is 70-80°C, and the reaction time is 10-12 hours. The crude product of N2-isobutyl-4,7-dibromo-substituted benzotriazole is obtained, which is crudely purified by recrystallization from petroleum ether and then purified by column chromatography. The elution condition is PE:EA=20:1, and the pure product of N2-isobutyl-4,7-dibromo-substituted benzotriazole is obtained.

9. The method according to claim 3, characterized in that: Step 3) The specific steps are: dissolving N2-isobutyl-4,7-dibromo-substituted benzotriazole and different substituted phenylboronic acids in an organic solvent, then adding a base, adding a Suzuki coupling catalyst under nitrogen protection, controlling the reaction temperature between 60-100° C., reacting for 4-8 hours to obtain a crude N2-isobutyl-substituted benzotriazole derivative, and performing post-treatment to obtain the corresponding product.

10. Application of the materials represented by Formula I to Formula III in the preparation of light-converting films, characterized in that: The membrane material is polyvinyl alcohol and polymethyl methacrylate.

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