Light capture system based on polybenzyl ether dendrimer as well as preparation method and application of light capture system

Abstract

The invention discloses a light capture system based on a polybenzyl ether dendrimer as well as a preparation method and application of the light capture system. According to the light capture system, a core mono-cyano ethylene modified polybenzyl ether dendrimer is used as a light acquisition antenna and an energy donor, and a fluorescent dye is used as an energy receptor; the core mono-cyano ethylene modified polybenzyl ether dendrimer and the fluorescent dye are co-assembled in a solution to form a light capture system. The light capture system provided by the invention has excellent aggregation-induced emission performance, obviously enhanced fluorescence and narrower emission band, and can still maintain better energy transfer and ultrahigh antenna effect under a high donor-acceptor ratio; in addition, the preparation process is green and environment-friendly, and the light capture system is stable in structure and can be stored for a long time.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a light-harvesting system based on polybenzyl ether dendrimers, and a preparation method and application thereof. Background Art

[0002] The light-harvesting system plays a vital role in the natural photosynthesis process. Correspondingly, the artificial light-harvesting system simulated by researchers with inspiration from the natural light-harvesting system not only provides the possibility for the development of new advanced functional materials and solving the energy crisis, but also has important guiding significance for the in-depth study and understanding of the complex structure and functional mechanism of the natural photosynthetic system.

[0003] The materials of artificial light harvesting systems include polymers, metal-organic frameworks, dendrimers, supramolecular self-assembly systems, nanocrystals and DNA. Among them, supramolecular self-assembly is one of the feasible methods to construct artificial light harvesting systems, and its non-covalent interactions also provide a favorable way to improve the efficiency of light harvesting. A series of supramolecular assemblies such as metal rings / cages / stacks, supramolecular polymers, biomacromolecules and other assemblies have been successfully used to construct efficient artificial light harvesting systems. However, the existing artificial light harvesting systems still have complex and time-consuming synthesis routes, and cannot avoid energy loss caused by aggregation quenching. Therefore, how to develop a simple method to construct an efficient artificial light harvesting system remains a challenging task.

[0004] Dendrimers are a new type of macromolecule developed in the 1980s. They are a type of macromolecule with a highly branched structure obtained by the stepwise and repeated reaction of branching units. Compared with traditional linear polymers, dendrimers have the following significant characteristics: (1) Dendrimers have a clear molecular weight and molecular size, and their structure is regular. The molecular volume, shape and functional group can be precisely controlled at the molecular level; (2) Dendrimers generally start from the core and continue to branch outward. When the generation number is low, it is generally an open molecular configuration. As the generation number increases, the molecule changes from an open loose configuration to a spherical three-dimensional structure with a tight outside and a loose inside. The molecule has a wide cavity inside and a very high functional group density on the surface of the molecule; (3) Dendrimers have good reactivity and tolerance. A large number of reactive or functional groups can be modified at the core and end of the molecule to construct materials with special functions. Summary of the invention

[0005] In view of the above technical problems, the present invention provides a light-harvesting system based on polybenzyl ether dendrimers, and a preparation method and application thereof. The light-harvesting system has good stability in the aqueous phase and has the advantages of simple preparation, greenness, low cost and multi-color luminescence.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention provides a light harvesting system based on polybenzyl ether dendrimers, wherein the light harvesting system uses a core monocyanoethylene-modified polybenzyl ether dendrimer as a light harvesting antenna and energy donor, and a fluorescent dye as an energy acceptor;

[0008] The core monocyanoethylene-modified polybenzyl ether dendrimer and the fluorescent dye are co-assembled in a solution to form the light-harvesting system;

[0009] The chemical structure of the core monocyanoethylene-modified polybenzyl ether dendrimer is shown in formula (1):

[0010]

[0011] In formula (1), R1 is selected from hydrogen (H) and Any one of; R2, R3 are each isolated and selected from any one of -COOMe, -F, -Cl, -Br, -CF3, -CH3 and -OCH3.

[0012] As a preferred embodiment, the fluorescent dye is selected from at least one of Nile Red (NiR) and Eosin Y (ESY); the chemical structures of Nile Red and Eosin Y are shown in Formula (2) and Formula (3), respectively:

[0013]

[0014] In the technical solution of the present invention, Nile Red and Eosin Y can be used alone to obtain a light-harvesting system for primary fluorescence resonance energy transfer, and can be used in combination to obtain a light-harvesting system for secondary fluorescence resonance energy transfer.

[0015] As a preferred embodiment, the molar concentration ratio of the core monocyanoethylene-modified polybenzyl ether dendrimer to the fluorescent dye in the solution is 50-2000:1, for example, 50:1, 100:1, 500:1, 1000:1, 1500:1, 2000:1 or any ratio therebetween.

[0016] As a preferred embodiment, the method for preparing the core monocyanoethylene-modified polybenzyl ether dendrimer comprises the following steps:

[0017] (1) reacting 3,5-dihydroxybenzaldehyde / 3,4,5-trihydroxybenzaldehyde with 3,5-dichlorobenzyl bromide in a solvent at 80-100° C. under the action of a base;

[0018] (2) reacting the reaction product of step (1) with 3,5-bis(trifluoromethyl)benzyl cyanide in a solvent at 80 to 120° C. under the action of a base;

[0019] Preferably, in step (1), the base is potassium carbonate and / or cesium carbonate; the solvent is acetone and / or N,N-dimethylformamide (DMF); the ratio of the amount of 3,5-dihydroxybenzaldehyde / 3,4,5-trihydroxybenzaldehyde to the amount of 3,5-dichlorobenzyl bromide and the amount of the base is 1:2.5-3.5:4-5; the reaction time is 12-24 hours;

[0020] Preferably, in step (2), the base is potassium tert-butoxide; the solvent is ethanol; the molar ratio of the reaction product of step (1) to 3,5-bis(trifluoromethyl)benzeneacetonitrile and the base is 1:1-2:1-2; and the reaction time is 24-36 hours.

[0021] In a second aspect, the present invention provides a method for preparing the above-mentioned light harvesting system, comprising the following steps:

[0022] A solution containing the core monocyanoethylene-modified polybenzyl ether dendrimer and a fluorescent dye is added into a poor solvent, and nanoparticles are formed by ultrasonic oscillation to obtain the light harvesting system.

[0023] As a preferred embodiment, the solvent of the solution containing the core monocyanoethylene-modified polybenzyl ether dendrimer and the fluorescent dye is a hydrophilic organic solvent selected from at least one of tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide (DMF) and acetonitrile;

[0024] Preferably, the poor solvent is water;

[0025] Preferably, the ultrasonic oscillation time is 1 to 5 minutes.

[0026] In a third aspect, the present invention provides the use of the above light harvesting system in the preparation of white light emitting materials.

[0027] In some specific embodiments, the excitation wavelength of the white light emitting material is 365 nm.

[0028] The above technical solution has the following advantages or beneficial effects:

[0029] The light-harvesting system provided by the present invention uses a core monocyanoethylene-modified polybenzyl ether dendrimer as a light-harvesting antenna and energy donor and a fluorescent dye as an energy acceptor, and is constructed by co-assembling in a solution to form water-dispersible nanoparticles.

[0030] The light capture system provided by the present invention has the following advantages:

[0031] (1) In the light-harvesting system provided by the present invention, the core monocyanoethylene-modified polybenzyl ether dendrimer serves as an assembly unit and energy donor, which can form a stable supramolecular nanoassembly in a variety of organic solvents or aqueous solutions, and in particular, can be assembled into supramolecular nanoparticles with good water dispersibility in aqueous phase. The nanoparticles have excellent aggregation-induced emission properties, providing a solid foundation for the construction of an efficient light-harvesting system;

[0032] (2) The light-harvesting system provided by the present invention can still maintain good energy transfer at a high donor / acceptor ratio, and its energy transfer efficiency can reach up to 99.6%; and it also has a narrow emission band and a high antenna effect: the emission half-peak width of the acceptor is narrowed from 72nm of the donor to 34nm of the acceptor, which is nearly 2.1 times narrower than the half-peak width of the donor, making the luminescent color purer, and the antenna effect can reach up to 97.5 times;

[0033] (3) The light-harvesting system provided by the present invention is a water-dispersible nanoparticle constructed by co-assembly of dendrimers and dye molecules in a solution, which has the advantages of low cost, green environmental protection, stable structure and suitability for application in biological systems;

[0034] (4) The fluorescence color of the light-harvesting system provided by the present invention is adjustable. As the acceptor ratio increases, the fluorescence color changes from green to red, and the change trend crosses the white light emission band, so that an efficient white light emitting material can be prepared. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 1 and 1. The fluorescence spectrum (a) and fluorescence intensity variation trend (b) of the compound CS-G1 measured in Example 3 of the present invention in solvents with different water contents.

[0036] Figure 2 It is the fluorescence spectrum diagram (a) and the fluorescence intensity variation trend diagram (b) of the compound CS-AB3-G1 measured in Example 3 of the present invention in solvents with different water contents.

[0037] Figure 3 It is the fluorescence spectrum and CIE coordinate diagram of the light harvesting system with different donor / acceptor concentration ratios prepared by compound CS-AB3-G1 in Example 4 of the present invention.

[0038] Figure 4 It is the fluorescence spectrum and CIE coordinate diagram of the light harvesting system with different donor / acceptor concentration ratios prepared by compound CS-AB3-G1 in Example 5 of the present invention.

[0039] Figure 5 1 is a white light emission fluorescence spectrum and a CIE coordinate diagram of the nanoparticle assembly solution prepared in Example 6 of the present invention. DETAILED DESCRIPTION

[0040] The following embodiments are only some embodiments of the present invention, rather than all embodiments. Therefore, the detailed description in the embodiments of the present invention provided below is not intended to limit the scope of the present invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the protection scope of the present invention.

[0041] In the present invention, unless otherwise specified, all equipment and raw materials can be purchased from the market or are commonly used in the industry. The methods in the following embodiments are all conventional methods in the art unless otherwise specified.

[0042] Example 1 Preparation of core monocyanoethylene modified polybenzyl ether dendrimer compound CS-G1

[0043] This example provides a core monocyanoethylene-modified polybenzyl ether dendrimer compound CS-G1, the preparation process of which is as follows:

[0044]

[0045] The specific steps are:

[0046] In a 250mL double-necked flask equipped with a stirring magnet, 3,5-dihydroxybenzaldehyde (1.84g, 10mmol), 3,5-dichlorobenzyl bromide (6.17g, 31mmol), K2CO3 (6.21g, 45mmol) and acetone (50mL) were added in sequence; heated to reflux in a metal bath at 80°C overnight under nitrogen protection, and the reaction progress was tracked by TLC during the period; after the reaction, the acetone solvent was removed in vacuo, and 150mL of dichloromethane and 50mL of water were added for extraction, and the aqueous phase was extracted twice with 50mL of dichloromethane respectively, the organic phases were combined, dried with anhydrous sodium sulfate, filtered, and the solvent was removed in vacuo to obtain a solid crude product; the obtained crude product was recrystallized from methanol to obtain a white solid G1-CHO with a yield of 92%;

[0047] In a 100mL reaction tube equipped with a stirring magnetic bar, G1-CHO (0.3g, 0.658mmol), 3,5-bis(trifluoromethyl)benzyl cyanide (0.333g, 1.316mmol), potassium tert-butoxide (0.148g, 1.316mmol) and ultra-dry ethanol (20mL) were added in sequence; the reaction was carried out in a metal bath at 100°C under nitrogen protection for 24h, and the reaction progress was tracked by TLC during the reaction; after the reaction was completed, the reaction was cooled to room temperature, a large amount of product precipitated, filtered, and the solid crude product was washed with a large amount of ethanol; the obtained crude product was purified by silica gel flash column chromatography to obtain a white solid CS-G1 with a yield of 56%.

[0048] The H NMR spectrum of G1-CHO prepared in this example 1 HNMR (400MHz, CDCl3, δ): 5.05 (s, ArCH2O, 8H), 6.82 (t, J = 2.3Hz, ArH, 1H), 7.10 (d, J = 2.3Hz, ArH, 2H), 7.32-7.34 (m, ArH, 6H). 13 CNMR (100MHz, CDCl3, δ): 191.4, 159.9, 139.5, 138.6, 135.4, 128.4, 125.6, 108.5, 108.5, 68.8.

[0049] High resolution mass spectrum (HRMS-ESI) of G1-CHO prepared in this example: 21 H 15 O3Cl4 + ([M+H] + ); calculated molecular ion peak value: m / z456.97403, measured value: m / z456.97388.

[0050] The H-NMR spectrum of CS-G1 prepared in this example 1 HNMR (400MHz, CDCl3, δ): 5.04 (s, ArCH2O, 4H), 5.05 (s, ArCH2O, 4H), 6.58 (t, J = 2.1Hz, ArH, 1H), 6.66 (t, J = 2.1Hz ,ArH,1H),6.89(d,J=2.1Hz,ArH,2H),7.12(d,J=2.1Hz,ArH,2H),7.34(s,ArH,12H),7.41(s,ArCH=C(CN)Ar,1H). 13 CNMR (100MHz, CDCl3, δ): 159.8,159.6,142.5,139.8,139.7,136.6,135.4,135.3, 135.3,128.3,125.6,117.8,112.0,108.5,105.8,105.1,102.8,77.2,68.7,68.7.

[0051] High resolution mass spectrum (HRMS-ESI) of CS-G1 prepared in this example: 43 H 28 NO4Cl8 + ([M+H] + ); calculated molecular ion peak value: m / z905.94621, measured value: m / z905.94678.

[0052] Example 2 Preparation of core monocyanoethylene modified dendrimer compound CS-AB3-G1

[0053] This example provides a core monocyanoethylene modified dendrimer compound CS-AB3-G1, the preparation process of which is as follows:

[0054]

[0055] The specific steps are:

[0056] In a 250mL double-necked flask equipped with a stirring magnet, 3,4,5-trihydroxybenzaldehyde (1.84g, 10mmol), 3,5-dichlorobenzyl bromide (6.17g, 31mmol), K2CO3 (6.21g, 45mmol) and ultra-dry DMF (50mL) were added in sequence; the reaction was carried out overnight in a metal bath at 80°C under nitrogen protection, and the reaction progress was tracked by TLC during the reaction; after the reaction was completed, 200mL of water was added to the reaction system to precipitate the product, which was filtered and the solid crude product was washed with a large amount of water; the crude product was recrystallized from methanol to obtain a white solid AB3-G1-CHO with a yield of 95%;

[0057] In a 100mL reaction tube equipped with a stirring magnetic bar, AB3-G1-CHO (0.5g, 0.792mmol), 3,5-bis(trifluoromethyl)benzyl cyanide (0.401g, 1.585mmol), potassium tert-butoxide (0.178g, 1.585mmol) and ultra-dry ethanol (40mL) were added in sequence; the reaction was carried out in a metal bath at 100°C under nitrogen protection for 24h, during which the reaction progress was tracked by TLC; after the reaction was completed, the reaction was cooled to room temperature, a large amount of product precipitated, filtered, and the solid crude product was washed with a large amount of ethanol; the obtained crude product was purified by silica gel flash column chromatography to obtain a white solid CS-AB3-G1 with a yield of 53%.

[0058] The H NMR spectrum of AB3-G1-CHO prepared in this example 1 H NMR (400MHz, CDCl3, δ): 5.07 (s, ArCH2O, 2H), 5.10 (s, ArCH2O, 4H), 7.19 (s, ArH, 2H), 7.27-7 .29(m,ArH,3H),7.31(d,J=1.7Hz,ArH,4H),7.35(t,J=1.7Hz,ArH,2H),9.85(s,ArCHO,1H). 13C NMR (100MHz, CDCl3, δ): 190.5, 152.7, 143.0, 140.3, 139.3, 135.5, 135.0, 132.3, 128.5, 128.3, 126.2, 125.6, 109.0, 73.8, 69.9.

[0059] High resolution mass spectrum (HRMS-ESI) of AB3-G1-CHO prepared in this example: 28 H 19 O4Cl6 + ([M+H] + ); calculated molecular ion peak value: m / z 632.93500, measured value: m / z 632.93494.

[0060] The H NMR spectrum of CS-AB3-G1 prepared in this example 1 H NMR (400MHz, CDCl3, δ): 5.01 (s, ArCH2O, 2H), 5.06 (s, ArCH2O, 2H), 5.10 (s, ArCH2O, 4H), 5.11 (s, ArCH2O, 4H) ,6.90(s,ArH,2H),7.19(s,ArH,2H),7.20(s,ArCH=C(CN)Ar,1H),7.30(s,ArH,4H),7.33-7.35(m,ArH,14H). 13 C NMR (100MHz, CDCl3, δ): 155.8, 155.5, 144.9, 144.8, 143.8, 143.8, 142.9, 142.0, 138.5, 138.1, 133.9, 132.8,131.6,131.6,131.4,129.5,129.5,128.9,128.9,121.3,113.8,112.1,109.3,73.2,73.0,71.1.

[0061] High resolution mass spectrum (HRMS-ESI) of CS-AB3-G1 prepared in this example: 57 H 36 NO6Cl 12 + ([M+H] + ); calculated molecular ion peak value: m / z 1255.87110, measured value: m / z 1255.87110.

[0062] Example 3

[0063] In this example, the fluorescence intensity of the core monocyanoethylene modified polybenzyl ether dendrimer compound prepared in Example 1-2 in solution state and aggregated state was tested. Taking compound CS-AB3-G1 as an example, the test process is as follows:

[0064] Take a 100mL volumetric flask and prepare 10 -3 mol / L tetrahydrofuran solution of compound CS-AB3-G1;

[0065] Take 11 10 mL sample bottles, numbered 0 to 10, and add 0.5 mL of the tetrahydrofuran solution of the above compound CS-AB3-G1 into each sample bottle using a pipette;

[0066] Tetrahydrofuran 9.5mL, 8.5mL, 7.5mL, 6.5mL, 5.5mL, 5.5mL, 3.5mL, 2.5mL, 1.5mL, and 0.5mL were added to the test tubes labeled 0 to 9, respectively; then deionized water 1.0mL, 2.0mL, 3.0mL, 4.0mL, 5.0mL, 6.0mL, 7.0mL, 8.0mL, 9.0mL, and 9.5mL were added to the test tubes labeled 1 to 10, respectively, to obtain 5×10 - 5 mol / L solution of compound CS-AB3-G1; the prepared solution was sonicated in an ultrasonic instrument for 60 seconds and then subjected to fluorescence spectrum testing.

[0067] Figure 1-2 The fluorescence spectra and fluorescence enhancement trend diagrams of compounds CS-G1 and CS-AB3-G1 in the dissolved state and the aggregated state are shown respectively. It can be seen from the figures that the compounds CS-G1 and CS-AB3-G1 synthesized by the present invention have excellent aggregation-induced fluorescence characteristics, wherein the luminescence efficiency of CS-G1 in the aggregated state (tetrahydrofuran-water mixed solution with a water content of 95 vol%) is 6.3 times higher than that in the dissolved state (tetrahydrofuran solution), and the luminescence efficiency of CS-AB3-G1 in the aggregated state (tetrahydrofuran-water mixed solution with a water content of 95 vol%) is 299.8 times higher than that in the dissolved state (tetrahydrofuran solution). In addition, the system also exhibits an obvious dendritic molecular effect. With the increase of the number of dendritic molecules at both ends, its self-assembly effect in the aqueous phase is the best, and it also exhibits the strongest fluorescence intensity and aggregation-induced fluorescence enhancement performance.

[0068] Example 4 Preparation of light harvesting system

[0069] In this example, the above compound CS-AB3-G1 is used as a light harvesting antenna and energy donor, and Nile red (NiR) is used as an energy acceptor to prepare a light harvesting system, and the process is as follows:

[0070] Step 1: prepare a concentration of 1×10 -3 5 mL of tetrahydrofuran solution of mol / L compound CS-AB3-G1;

[0071] Step 2, preparing tetrahydrofuran solutions of Nile red of different concentrations;

[0072] Step 3, mixing a trace amount of donor compound CS-AB3-G1 solution (D) and a trace amount of Nile red receptor solution (A) at different final concentration ratios (D / A=50 / 1, 100 / 1, 500 / 1, 1000 / 1, 1500 / 1, 2000 / 1, molar concentration ratio) (sample bottles are numbered 1 to 6), and then placing sample bottles No. 1 to 6 in a vacuum drying oven to completely evaporate the solvent;

[0073] Step 4, using a pipette, add 1.0 mL of tetrahydrofuran to bottles 1 to 6 respectively to dissolve the mixture;

[0074] Step 5, respectively, add the above mixed solution dropwise to 4.0 mL of deionized water; ultrasonically oscillate for 1 min, shaking continuously during the process, to obtain aqueous solutions of nanoparticle assemblies with different donor / acceptor concentration ratios, wherein the concentration of the donor CS-AB3-G1 compound is 5×10 -5 mo1 / L.

[0075] The fluorescence of the nanoparticle assembly solution prepared in this example was measured using a fluorescence spectrophotometer, and the measured fluorescence spectrum was converted into a CIE color coordinate diagram one by one. The excitation wavelength was 365 nm. The test results are shown in Figure 3 ; Wherein, the abscissa x of the CIE color coordinate diagram is the red component, and the ordinate y is the green component. The energy transfer efficiency and antenna efficiency are calculated based on the spectrum data, and the results are shown in Table 1.

[0076] from Figure 3 As can be seen from Table 1, the fluorescence peak of the compound CS-AB3-G1 as the energy donor D, i.e., the fluorescence intensity at 503 nm, decreases step by step with the increase of the concentration of the energy acceptor A (NiR); while the fluorescence peak of the energy acceptor A, i.e., the fluorescence intensity at 606 nm, increases step by step with the increase of the concentration of the energy acceptor A (NiR), indicating that it has a good light capture effect. Figure 3 The fluorescence intensity of the donor and acceptor at different concentrations shows that the optimal half-peak width of the donor is 72nm and that of the acceptor is 48nm; the energy transfer efficiency of the system with D / A=50 / 1 can reach 99.6%, and the antenna efficiency (Antennaeffect) can reach 80.9. The antenna efficiency of the system with D / A=100 / 1 is as high as 97.5. In the CIE color coordinate diagram, the path of the coordinate point increases from green to yellow and red as the molar concentration of the energy acceptor A increases.

[0077] Table 1

[0078]

[0079] Example 5 Preparation of light harvesting system

[0080] In this example, the above compound CS-AB3-G1 is used as a light harvesting antenna and energy donor, and eosin Y (ESY) is used as an energy acceptor to prepare a light harvesting system. The process is as follows:

[0081] Step 1: prepare a concentration of 1×10 -3 5 mL of tetrahydrofuran solution of mol / L compound CS-AB3-G1;

[0082] Step 2, preparing tetrahydrofuran solutions of Eosin Y of different concentrations;

[0083] Step 3, mixing a trace amount of donor compound CS-AB3-G1 solution (D) and a trace amount of eosin Y acceptor solution (A) at different final concentration ratios (D / A=50 / 1, 100 / 1, 500 / 1, 1000 / 1, 1500 / 1, 2000 / 1, molar concentration ratio) (numbered 1 to 6), and then placing sample bottles 1 to 6 in a vacuum drying oven to completely evaporate the solvent;

[0084] Step 4, using a pipette, add 1.0 mL of tetrahydrofuran to bottles 1 to 6 respectively to dissolve the mixture;

[0085] Step 5, respectively, add the above mixed solution dropwise to 4.0 mL of deionized water; ultrasonically oscillate for 1 min, shaking continuously during the process, to obtain aqueous solutions of nanoparticle assemblies with different donor / acceptor concentration ratios, wherein the concentration of the donor CS-AB3-G1 compound is 5×10 -5 mo1 / L.

[0086] The fluorescence of the nanoparticle assembly solution prepared in this example was measured using a fluorescence spectrophotometer, and the measured fluorescence spectrum was converted into a CIE color coordinate diagram one by one. The excitation wavelength was 365 nm. The test results are shown in Figure 4 ; Wherein, the abscissa x of the CIE color coordinate diagram is the red component, and the ordinate y is the green component. The energy transfer efficiency and antenna efficiency are calculated based on the spectrum data, and the results are shown in Table 2.

[0087] Table 2

[0088]

[0089] From Table 2 and Figure 4It can be seen that the fluorescence peak of the compound CS-AB3-G1 as energy donor D, that is, the fluorescence intensity at 503nm, decreases step by step with the increase of the concentration of energy acceptor A (ESY); while the fluorescence peak of energy acceptor A, that is, the fluorescence intensity at 559nm, increases step by step with the increase of the concentration of energy acceptor A (ESY), indicating that it also has a good light capture effect. From the fluorescence intensity of the donor and acceptor at different concentrations in the figure, it can be seen that the optimal half-peak width of the donor is 72nm, and that of the acceptor is 34nm; the energy transfer efficiency of the system with D / A=50 / 1 can reach 91.5%, and the antenna efficiency (Antenna effect) can reach 48.3. In the CIE color coordinate diagram, the path of the coordinate point changes from green to yellow as the molar concentration of energy acceptor A increases.

[0090] Example 6 Preparation of white luminescent material

[0091] In this example, the above compound CS-AB3-G1 is used as an energy donor and Nile red (NiR) is used as an acceptor to prepare a white luminescent material. The process is as follows:

[0092] Step 1: prepare a concentration of 1×10 -3 5 mL of tetrahydrofuran solution of mol / L compound CS-AB3-G1;

[0093] Step 2: Prepare a concentration of 1×10 -4 mol / L Nile red in tetrahydrofuran solution;

[0094] Step 3, mixing a trace amount of donor compound CS-AB3-G1 solution (D) and a trace amount of Nile red receptor solution (A) at a final molar concentration ratio of 100:1, and then placing the sample bottle in a vacuum drying oven to completely evaporate the solvent;

[0095] Step 4, add 3.0 mL of tetrahydrofuran to the sample bottle using a pipette to dissolve the mixture;

[0096] Step 5, add 2.0 mL of deionized water to the above mixed solution; ultrasonic oscillate for 1 min, shaking continuously during the process, to obtain a nanoparticle assembly solution with a donor / acceptor concentration ratio of 100:1, wherein the concentration of the donor compound CS-AB3-G1 is 5×10 -5 mol / L, the concentration of the receptor Nile red solution was 5×10 -7 mo1 / L.

[0097] The fluorescence spectrum of the nanoparticle assembly solution prepared in this example was measured using a fluorescence spectrophotometer with an excitation wavelength of 365 nm. The test results are shown in Figure 5The fluorescence spectrum was plotted as a CIE coordinate diagram, and its fluorescence CIE coordinates were (0.32, 0.33), which was consistent with the standard white light emission coordinates (0.33, 0.33). The naked eye can also see that its solution emits white light under 365nm ultraviolet light. From its fluorescence spectrum, it can be seen that its spectrum evenly covers the entire visible light range, which is the main reason why it can emit white light.

[0098] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A light harvesting system based on polybenzyl ether dendrimers, characterized in that: The light-harvesting system uses a core monocyanoethylene-modified polybenzyl ether dendrimer as a light-harvesting antenna and energy donor, and a fluorescent dye as an energy acceptor; The core monocyanoethylene-modified polybenzyl ether dendrimer and the fluorescent dye are co-assembled in a solution to form the light-harvesting system; The chemical structure of the core monocyanoethylene-modified polybenzyl ether dendrimer is shown in formula (1): In formula (1), R1 is selected from hydrogen (H) and Any one of; R2, R3 are each isolated and selected from any one of -COOMe, -F, -Cl, -Br, -CF3, -CH3 and -OCH3.

2. The light capture system according to claim 1, characterized in that The fluorescent dye is selected from at least one of Nile Red and Eosin Y.

3. The light harvesting system according to claim 1, characterized in that The molar concentration ratio of the core monocyanoethylene-modified polybenzyl ether dendrimer to the fluorescent dye in the solution is 50-2000:

1.

4. The light capture system according to claim 1, characterized in that The method for preparing the core monocyanoethylene-modified polybenzyl ether dendrimer comprises the following steps: (1) reacting 3,5-dihydroxybenzaldehyde / 3,4,5-trihydroxybenzaldehyde with 3,5-dichlorobenzyl bromide in a solvent at 80-100° C. under the action of a base; (2) reacting the reaction product of step (1) with 3,5-bis(trifluoromethyl)benzyl cyanide in a solvent at 80-120° C. under the action of a base.

5. The light capture system according to claim 4, characterized in that In step (1), the base is potassium carbonate and / or cesium carbonate; the solvent is acetone and / or N,N-dimethylformamide (DMF); the ratio of the amount of 3,5-dihydroxybenzaldehyde / 3,4,5-trihydroxybenzaldehyde to the amount of 3,5-dichlorobenzyl bromide and the amount of the base is 1:2.5-3.5:4-5; and the reaction time is 12-24 hours.

6. The light capture system according to claim 4, characterized in that In step (2), the base is potassium tert-butoxide; the solvent is ethanol; the molar ratio of the reaction product of step (1) to 3,5-bis(trifluoromethyl)benzyl cyanide and the base is 1:1-2:1-2; and the reaction time is 24-36 hours.

7. The method for preparing the light harvesting system according to any one of claims 1 to 6, characterized in that: The following steps are involved: A solution containing the core monocyanoethylene-modified polybenzyl ether dendrimer and a fluorescent dye is added into a poor solvent, and nanoparticles are formed by ultrasonic oscillation to obtain the light harvesting system.

8. The preparation method according to claim 7, characterized in that: The solvent of the solution containing the core monocyanoethylene-modified polybenzyl ether dendrimer and the fluorescent dye is a hydrophilic organic solvent selected from at least one of tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide, N,N-dimethylformamide and acetonitrile.

9. The preparation method according to claim 7, characterized in that: The poor solvent is water; the ultrasonic oscillation time is 1 to 5 minutes.

10. Use of the light harvesting system according to any one of claims 1 to 6 in the preparation of white light emitting materials.

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