A continuous energy transfer light harvesting system, its preparation method and application in color-tunable latent fingerprint imaging

Abstract

The application discloses a continuous energy transfer light trapping system, a preparation method thereof and application thereof in color-adjustable latent fingerprint imaging. A nanoparticle self-assembled from a fluorescent molecule G with an aggregation-induced emission (AIE) characteristic and a water-soluble pillar[5]arene (WP5) is used as a loading platform and an energy donor, a hydrophobic dye DBT and SR101 are used as a first and a second energy acceptor respectively, and a continuous energy transfer light trapping system is constructed, which has a wide color control range. The system is mixed with montmorillonite to prepare a multicolor fluorescent fingerprint powder, and is applied to high-resolution fluorescent imaging of a latent fingerprint, so that three-level information of the fingerprint can be clearly generated. The fluorescent fingerprint powder has strong light emission and multicolor adjustability, and is suitable for different background matrices.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of supramolecular fluorescent materials and information security, and particularly relates to a continuous energy transfer light harvesting system, a preparation method thereof and application thereof in color-tunable latent fingerprint imaging. BACKGROUND

[0002] Fingerprint is mainly composed of ridge lines and grooves on the skin of human fingers, and is one of important means of individual identification, especially in criminal investigation. However, the fingerprint left in the scene is usually invisible to the naked eye, namely latent fingerprint (LFP). Therefore, the visualization of LFP is particularly important. Among various techniques for LFP development, fluorescent imaging has attracted great attention due to its high resolution and high contrast. However, the fluorescent materials based on traditional organic dyes usually suffer from aggregation-induced quenching (ACQ) effect, which seriously affects the quality of fluorescent imaging in the process of powder dusting. The use of aggregation-induced fluorescence (AIE) fluorophores is a novel alternative. However, due to the tedious covalent modification of AIE fluorophores, the color-tunable AIE materials for LFP development in different scenarios is still a great challenge.

[0003] The artificial light harvesting system based on supramolecular self-assembly has attracted great interest due to its great application potential in cell imaging, photocatalysis, information encryption and light-emitting devices. Moreover, the fluorescence resonance energy transfer (FRET) between the AIE donor and the ACQ acceptor in the system makes the material have color-tunable emission. Inspired by the continuous energy transfer in natural LHSs, the secondary energy transfer artificial light harvesting system (LHSs) can make the energy excited by the donor be utilized to a greater extent, and the color-tunable region is wider, but there is no related research on color-tunable LFP imaging. SUMMARY

[0004] In view of the above technical problems, the present application provides a supramolecular continuous energy transfer light harvesting system and an application method thereof in multicolor-tunable high-resolution latent fingerprint imaging. To achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0005] A continuous energy transfer light harvesting system, the continuous energy transfer light harvesting system takes a compound G with AIE characteristics as a guest, and WP5 as a host, and an assembly formed by host-guest interaction in water as a platform of light harvesting acceptor and energy donor; a hydrophobic fluorescent dye DBT and SR101 are sequentially used as a first energy acceptor and a second energy acceptor;

[0006] The structure of the compound G is shown in formula (I), and the structure of WP5 is shown in formula (II):

[0007]

[0008] Preferably, The concentration in water is greater than 3.2 μM.

[0009] Preferably, the concentration of compound G is 2 x 10 -5 -4 M. At this concentration, compound G has no self-assembly in water, no Tyndall effect, and no fluorescence emission phenomenon.

[0010] Preferably, the molar ratio of compound G and WP5 is 1:0.05-1:2, preferably 1:0.7;

[0011] Preferably, the molar ratio of DBT and is 1:50-1:500, and the molar ratio of SR101 and is 1:1000-15:1000.

[0012] Preferably, when compound G and DBT are mixed, the first fluorescence resonance energy transfer occurs, forming The fluorescence color gradually changes from cyan to yellow; DBT is 4,7-bis(2-thienyl)-benzo[2,1,3]thiadiazole. The structure of DBT is The absorption wavelength of DBT overlaps with the emission wavelength of compound G, ensuring that the first fluorescence resonance energy transfer (FRET) occurs.

[0013] Preferably, SR101 is further added, the second fluorescence resonance energy transfer occurs, forming The fluorescence color gradually changes from yellow to red. The structure of SR101 is The absorption wavelength of SR101 overlaps with the emission wavelength of the first energy transfer, ensuring that the second fluorescence resonance energy transfer occurs.

[0014] The present application also provides a preparation method of the above-mentioned continuous energy transfer light trapping system, comprising the following steps:

[0015] (1) preparing compound G:

[0016] Compound 1 shown in formula (IV), 1,5-dibromopentane, K2CO3 and acetone are mixed, heated to reflux, cooled, extracted, dried, filtered, concentrated, and purified to obtain a white solid, which is compound 2 shown in formula (III);

[0017] Compound 2 is mixed with trimethylamine at a molar ratio of 1:10 and dissolved in anhydrous tetrahydrofuran, heated to reflux and stirred for 3 days, during which trimethylamine is added every day, and after the reaction is completed, the residue is washed with petroleum ether, ethyl acetate and acetone, and the obtained cyan fluorescent solid is compound G;

[0018] ​

[0019] (2) Preparation of the continuous energy transfer light harvesting system:

[0020] Compound G and WP5 are dissolved in water at a molar ratio of 1:0.05-1:2 and self-assembled to form nanoscale assemblies emitting cyan fluorescence Compound G and WP5 are dissolved in water at a molar ratio of 1:0.05-1:2 and self-assembled to form nanoscale assemblies emitting cyan fluorescence DBT and SR101 are mixed at a molar ratio of 500:1-50:1 (e.g. 50:1, 60:1, 80:1, 100:1, 200:1, 300:1, 400:1, 500:1 or any ratio therebetween), and after ultrasonication, a light harvesting system undergoing first-order fluorescence resonance energy transfer is obtained; SR101 is continuously added, and after ultrasonication, a continuous energy transfer light harvesting system is obtained, at which time The molar ratio of DBT and SR101 is 1000:20:1-1000:20:15 (e.g. 1000:20:1, 1000:20:3, 1000:20:6, 1000:20:9, 1000:20:12, 1000:20:14, 1000:20:15 or any ratio therebetween).

[0021] The application also provides use of the above continuous energy transfer light harvesting system in the preparation of a luminescent material, characterized in that the luminescent material is a tunable photoluminescent material having a fluorescence-tunable emission band and an excitation wavelength of 340 nm.

[0022] The application also provides use of the above continuous energy transfer light harvesting system in the field of latent fingerprint imaging, characterized in that the specific steps are as follows: solutions of the continuous energy transfer light harvesting system at different ratios are concentrated to fluorescent nanoparticles, montmorillonite is added and mixed uniformly, and the mixture is dried to prepare fingerprint powder.

[0023] Preferably, the following steps are included:

[0024] Step 1: hydrophobic fluorescent dyes DBT and SR101 are added to a mixed aqueous solution of compound G and WP5 to perform light harvesting behavior, and a supramolecular continuous energy transfer light harvesting system is prepared;

[0025] Step 2: solutions of the supramolecular light harvesting system at different ratios are concentrated and dried to prepare a series of fluorescent fingerprint powders;

[0026] Step 3: the fingerprint powder is sprinkled on a latent fingerprint, and excess fluorescent powder is blown away;

[0027] Step 4: the fingerprint image is recorded and analyzed.

[0028] Preferably, high-resolution three-level fingerprint imaging is obtained, including core points, lakes, short ridges, spikes, bifurcations, terminations and pores; so that the fingerprint powder can be used for fingerprint imaging on more material substrates, including but not limited to plastic, marble, wood, rubber, metal, textiles.

[0029] The above technical scheme has the following advantages or beneficial effects:

[0030] 1. The continuous energy transfer light trapping system provided by the present application can well simulate the continuous multiple energy transfer path of natural photosynthesis.

[0031] 2. The first energy transfer light trapping system provided by the present application can better transfer energy under a very high donor-acceptor ratio (500:1-50:1), and a unit acceptor can accept up to several hundred times the amount of energy transferred by the donor, while also having the advantages of high energy transfer and ultra-high antenna effect, with the highest energy transfer efficiency of the system reaching 62.1%, and the best antenna effect reaching 55.0.

[0032] 3. The second energy transfer light trapping system provided by the present application can still better transfer energy under a higher donor-acceptor ratio (1000:20:1-1000:20:15), and a unit acceptor can accept up to several hundred times or even thousands of times the amount of energy transferred by the donor, while also having the advantages of high energy transfer and antenna effect, with the highest energy transfer efficiency of the system reaching 37.2%, and the best antenna effect reaching 32.5.

[0033] 4. The fluorescence emission of the light trapping system provided by the present application is multicolor adjustable, and when hydrophobic fluorescent dye DBT is added, the fluorescence color changes from cyan to yellow, and yellow fluorescence emitting solid nanoparticles can be prepared; the yellow fluorescence emitting solid nanoparticles can be used for yellow fluorescence latent fingerprint imaging; when hydrophobic fluorescent dye SR101 is continuously added, the fluorescence color changes from yellow to red, and red fluorescence emitting solid nanoparticles can be prepared; the red fluorescence emitting solid nanoparticles can be used for red fluorescence latent fingerprint imaging.

[0034] 5. The fingerprint powder provided by the present application is color adjustable, and based on the tunability of the light trapping system from cyan to yellow to red, a series of fingerprint powders with fluorescence colors from cyan to yellow to red and intermediate colors, such as light yellow, orange, etc.

[0035] 6. The multicolor emitting fingerprint powder provided by the present application has the characteristics of multicolor tunability, strong emission and high contrast, and can be used for fingerprint imaging on more substrates, such as plastic, marble, wood, iron sheet with smooth surface, or rubber, tin paper, paper and textiles with soft and rough surface.

[0036] 7. The continuous energy transfer light harvesting system provided by the application is self-assembled into nanoparticles by host-guest interaction of compound G and WP5, which are uniformly dispersed in aqueous solution as energy donors, and has the effects of low cost and green environmental protection; and the structure is stable, the fluorescent solution can be stored for at least two weeks, and the prepared fingerprint fluorescent powder can be stored for more than one year. BRIEF DESCRIPTION OF DRAWINGS

[0037] The drawings incorporated in the specification and constituting a part thereof illustrate embodiments consistent with the present application and together with the description serve to explain the principles of the application, wherein:

[0038] Figure 1 It is a schematic diagram of the technical scheme of the application.

[0039] Figure 2 It is the fluorescence spectrum of the guest compound G and the host compound WP5 in different proportions in Example 1.

[0040] Figure 3 (a) is the energy transfer diagram with the first energy acceptor DBT; (b) is the energy transfer diagram with the second energy acceptor SR101. (a) is the energy transfer diagram with the first energy acceptor DBT; (b) is the energy transfer diagram with the second energy acceptor SR101. (a) is the energy transfer diagram with the first energy acceptor DBT; (b) is the energy transfer diagram with the second energy acceptor SR101.

[0041] Figure 4 It is the color-tunable fingerprint imaging diagram of the continuous energy transfer light harvesting system in different proportions.

[0042] Figure 5 It is the fingerprint analysis diagram in Example 1.

[0043] Figure 6 It is the nuclear magnetic resonance hydrogen (H NMR) spectrum of compound G. 1

[0044] Figure 7 It is the nuclear magnetic resonance carbon (C NMR) spectrum of compound G. 13

[0045] Figure 8 It is the high-resolution mass spectrum of compound G, [M] + = 310.2209. DETAILED DESCRIPTION

[0046] ​​​The following disclosure provides many different embodiments, or examples, for implementing different structures of the present application. For the purpose of simplification, the elements of the particular examples are described in the following disclosure. Of course, they are merely examples and are not intended to limit the present application. Furthermore, the present application can repeatedly refer to reference numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which does not indicate the relationship between the various embodiments and / or arrangements discussed.

[0047] In the present application, all the equipment and raw materials, etc. can be purchased from the market or commonly used in the industry, unless otherwise specified. The methods in the following examples are conventional methods in the art, unless otherwise specified.

[0048] Example 1

[0049] (1) Synthesis of compound 2:

[0050] Compound 2 was synthesized from compound 1, and the synthetic route is as follows:

[0051]

[0052] Compound 1 was synthesized according to the literature: J. Am. Chem. Soc, 2019, 141, 6224-6233.

[0053] The preparation process of compound 2 is as follows: compound 1 (0.93 g, 2.6 mmol), 1,5-dibromopentane (2.94 g, 12.8 mmol), K2CO3 (1.41 g, 10.2 mmol) and acetone (40 mL) were added into a 100 mL three-necked flask. Heat to reflux for 24 h. After the reaction was completed, the reaction solution was cooled to room temperature, separated, extracted with dichloromethane, dried with Na2SO4, filtered, concentrated by rotary evaporation. Purified by column chromatography (PE / EA, 50 / 1) to obtain white solid (1.09 g, yield 64%).

[0054] (2) Synthesis of compound G:

[0055] Compound G was synthesized from compound 2, and the structural formula of compound 2 is as follows:

[0056]

[0057] The preparation process of compound G is as follows: in a 100 mL three-necked flask, compound 1 (0.50 g, 0.75 mmol), trimethylamine (2.0 mL, 7.5 mmol) and anhydrous THF (40 mL) are added, heated to reflux, stirred for 3 days, during which time trimethylamine (2.0 mL) is added every day. Then, evaporate THF and excess triethylamine, the obtained solid is washed with petroleum ether, ethyl acetate and acetone in turn, to obtain white solid (0.42 g, yield 72%).

[0058] The nuclear magnetic hydrogen spectrum of compound G is as shown in Figure 6 .

[0059] The nuclear magnetic carbon spectrum of compound G is as shown in Figure 7 .

[0060] The high resolution mass spectrum of compound G is as shown in Figure 8 .

[0061] According to the experimental characterization described above, the structure of compound G is determined as:

[0062]

[0063] (3) Preparation of supramolecular nanoparticles:

[0064] Compound WP5 is synthesized according to the literature J. Mater. Chem. B, 2016, 4, 2819-2827, and its structure is as follows:

[0065]

[0066] Preparation process of supramolecular nanoparticles:

[0067] Step 1, prepare the mother liquor of G with a concentration of 5 × 10 -3 M;

[0068] Step 2, prepare the mother liquor of WP5 with a concentration of 4 × 10 -4 M;

[0069] Step 3, take an appropriate amount of mother liquor of G and WP5 with a pipette into a 5 mL volumetric flask, mix well, then add deionized water to constant volume, ultrasonic for 3 min to form water phase dispersed nanoparticles

[0070] (4) Fluorescence titration experiment of different host-guest ratios:

[0071] The water solution of the guest compound G was prepared with a concentration of 20 μM at 25°C, and different amounts of the host compound WP5 (1-40 μM) were added dropwise to the solution, and the fluorescence spectrum was measured. According to the change of the fluorescence intensity at 480 nm, the highest point corresponds to the concentration of 14 μM of the compound WP5, i.e. the optimal molar ratio of the compound G to the compound WP5 is 1:0.7.

[0072] In this embodiment, the fluorescence spectrum of the compound G was measured at an excitation wavelength of 340 nm, as shown in Fig. 1. Figure 2 In this embodiment, the fluorescence spectrum of the compound G was measured at an excitation wavelength of 340 nm, as shown in Fig. 1.

[0073] In this embodiment, the ultrasonic instrument used was a common ultrasonic cleaner in a laboratory, and the frequency was 40 kHz.

[0074] The critical aggregation concentration of the amphiphilic compound G and WP5 after complexation was 3.2 μM in water. Below this concentration, the compound mainly exists in a molecular form and has not yet aggregated, and cannot load the acceptor to form a light harvesting system.

[0075] (5) Preparation of a primary light harvesting system:

[0076] In this embodiment, the compound G was used as an energy donor, and the fluorescent dye DBT was used as a primary energy transfer acceptor, and the preparation method was as follows:

[0077] Step 1. Prepare a mother liquor of the compound G with a concentration of 5 x 10 -3 M;

[0078] Step 2. Prepare a mother liquor of WP5 with a concentration of 4 x 10 -4 M;

[0079] Step 3. Prepare a dimethyl sulfoxide solution of DBT as a mother liquor with a concentration of 5 x 10 -5 M;

[0080] Step 4. Take a certain amount of the mother liquor of the compound G, a certain amount of the mother liquor of WP5 and a certain amount of the mother liquor of DBT into a 5 mL volumetric flask using a pipette, mix well, add deionized water to constant volume, and ultrasonic for 3 min to form a nanoparticle aqueous solution (or add DBT to the aqueous solution to form nanoparticles after ultrasonic treatment); wherein the nanoparticle aqueous solution is a dynamic supramolecular assembly with dynamic reversibility); wherein the concentrations of the compound G, the compound WP5 and the compound DBT in the nanoparticle aqueous solution are shown in the following table:

[0081]

[0082] ​​​In this embodiment, the samples prepared by the above method were measured under 340 nm excitation. Nanoparticles, in this embodiment Nanoparticles with different proportions of donors The fluorescence spectrum of the energy acceptor DBT in aqueous solution is shown in the figure. Figure 3 As shown in a. The fluorescence spectra obtained from the above tests were used to characterize the energy transfer efficiency and antenna effect of the nanoparticles, as follows:

[0083] Based on the measured Nanoparticles and The fluorescence spectrum of the nanoparticles was used to calculate the first-step energy transfer efficiency (Φ) using equation S1. ET ):

[0084] Φ ET =1-I DA / I D (eq.S1)

[0085] Where I DA and I D They are and Fluorescence intensity at 480 nm under 340 nm excitation.

[0086] At [WP5] = 1.4 × 10 -5 M, [G] = 2 × 10 -5 M, [DBT] = 4 × 10 -7 M, (λ) ex =340nm,λ em Under the condition of 480 nm, the energy transfer efficiency (Φ) in water was calculated. ET The figure was 62.1%.

[0087] Based on the measured Nanoparticles and The fluorescence spectrum of the nanoparticles was used to calculate the antenna effect (AE) of the first step of energy transfer using equation S2:

[0088] AE = I' DA,340 / I DA,480 =(I DA,340 -I D,340 ) / I DA,480 (eq.S2)

[0089] Where I DA,340 and I DA,480 They are Fluorescence intensity at 560 nm under excitation at 340 nm and 480 nm. D,340 It means The emission spectrum of the compound WP5 was normalized at 480 nm, and the fluorescence intensity at 560 nm was measured under excitation at 340 nm.

[0090] The antenna effect value of the compound WP5 in water was measured to be 55.0 under the condition of [WP5]=1.4×10 -5 M, [G]=2×10 -5 M, [DBT]=4×10 -7 M.

[0091] (6) Preparation of the secondary light harvesting system:

[0092] In this embodiment, the compound WP5 was used as the energy donor, the fluorescent dye DBT was used as the first energy acceptor, and SR101 was used as the secondary energy acceptor, and the preparation method was as follows:

[0093] Step 1. Prepare the mother liquor of the compound G with a concentration of 5×10 -3 M;

[0094] Step 2. Prepare the mother liquor of WP5 with a concentration of 4×10 -4 M;

[0095] Step 3. Prepare the dimethyl sulfoxide solution of DBT as the mother liquor with a concentration of 5×10 -5 M;

[0096] Step 4. Prepare the dimethyl sulfoxide solution of SR101 as the mother liquor with a concentration of 1×10 -5 M;

[0097] Step 5. Use a pipette to take a certain amount of the mother liquor of G, a certain amount of the mother liquor of WP5, a certain amount of the mother liquor of DBT, and a certain amount of the mother liquor of SR101 into a 5 mL volumetric flask, mix well, then add deionized water to constant volume, and ultrasonic for 3 min to form a nanoparticle aqueous solution (or add SR101 to the aqueous solution and ultrasonic to form a nanoparticle aqueous solution); wherein the concentrations of the compound G, the compound WP5, the compound DBT, and the compound SR101 are shown in the following table:

[0098]

[0099] In this embodiment, the above-prepared nanoparticles were measured under excitation at 340 nm, and the fluorescence spectra of the nanoparticles with different proportions in this embodiment are shown in Figure 3 b. The fluorescence spectra obtained by the above tests in this embodiment characterized the energy transfer efficiency and the antenna effect of the nanoparticles, and the process was as follows: ​

[0100] Based on the measured Nanoparticles and The fluorescence spectrum of the nanoparticles was used to calculate the second-step energy transfer efficiency (Φ) using equation S3. ET ):

[0101] Φ ET =1-I DA / I D (eq.S3)

[0102] Where I DA and I D They are and Fluorescence intensity at 560 nm under 340 nm excitation.

[0103] At [WP5] = 1.4 × 10 -5 M, [G] = 2 × 10 -5 M, [DBT] = 4 × 10 -7 M, [SR101] = 3 × 10 -7 M, (λ) ex =340nm,λ em Under the condition of 560 nm, the energy transfer efficiency (Φ) in water was calculated. ET The figure was 37.2%.

[0104] Based on the measured Nanoparticles and The fluorescence spectrum of the nanoparticles was used to calculate the antenna effect (AE) of the first step of energy transfer using equation S4:

[0105] AE = I' DA,340 / I DA,560 =(I DA,340 -I D,340 ) / I DA,560 (eq.S4)

[0106] Where I DA,340 and I DA,560 They are Fluorescence intensity at 606 nm under excitation at 340 nm and 560 nm. D,340 It means The emission spectrum, after normalization at 560 nm, shows the fluorescence intensity at 606 nm under 340 nm excitation.

[0107] At [WP5] = 1.4 × 10 -5 M, [G] = 2 × 10 -5 M, [DBT] = 4 × 10 -7 M, [SR101] = 3 × 10 -7The antenna effect value in water was 32.5 measured under M condition.

[0108] (7) Application:

[0109] Light harvesting system for color-tunable latent fingerprint imaging:

[0110] In this embodiment, the different The nanoparticle solution of the light harvesting system with continuous energy transfer in different proportions obtained by the above method was concentrated and dried to obtain solid nanoparticles with multi-color fluorescence emission. The montmorillonite was ground and mixed uniformly, and then was sprinkled on the latent fingerprint, which could be recorded by photographic equipment under 365 nm ultraviolet lamp.

[0111] The steps are as follows:

[0112] The prepared 20 mL light harvesting system solution was concentrated to 5 mL, and then 0.2 g of montmorillonite after sufficient grinding was added to 5 mL of the concentrated solution, and water was removed by vacuum rotary evaporation. The obtained solid powder was vacuum dried for 4 h and stored in a desiccator for standby use. The amount of addition is shown in the following table:

[0113]

[0114]

[0115] The volunteer gently touched the glass substrate with the finger to leave a latent fingerprint that was difficult to see with the naked eye. The prepared fluorescent fingerprint powder was uniformly sprinkled on the latent fingerprint, and the excess fluorescent fingerprint powder on the substrate was blown away with an ear bulb. The fingerprint was placed under 365 nm ultraviolet lamp irradiation, and there was a very clear fingerprint image.

[0116] The fluorescent fingerprint powder with a series of multi-color emission from cyan to yellow to red (including intermediate colors such as light yellow, orange, etc.) is used for latent fingerprint imaging, which greatly widens the application range of fingerprint imaging, such as Figure 4 As shown in the table, the fluorescent intensity of the fluorescent fingerprint powder is high, the color contrast is strong, the imaging effect resolution is high, and the first, second and third information of the fingerprint can be clearly generated, as shown in the table. Figure 5

[0117] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the application embrace any and all variations of the present application that fall within the scope of the general inventive concept as defined in the claims and that the specification and examples be considered exemplary only with the true scope and spirit of the application indicated by the claims. This application is not limited in its application to the details set forth in the description or exemplified examples and the claims should be afforded the broadest interpretation under the non- statutory provisions of 35 U.S.C. 112 et seq.

[0118] ​​​It should be understood that the application is not limited to the precise construction which has been described above and which shown in the drawings, and that various modifications and changes can be made by those skilled in the art without departing from the scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A continuous energy transfer light harvesting system, characterized in that, The continuous energy transfer light harvesting system takes compound G with AIE characteristics as guest, WP5 as host, and forms an assembly WP5 in water through host-guest interaction G as a platform for light harvesting acceptor and energy donor; hydrophobic fluorescent dye DBT and SR101 as first and second energy acceptors, respectively; the DBT is 4,7-di(2-thienyl)-benzo[2,1,3]thiadiazole; The structure of the compound G is shown in formula (I), and the structure of the WP5 is shown in formula (II): Formula (I); Formula (II); The DBT and the WP5 The SR101 and the WP5 in a molar ratio of 1 :50 The SR101 and the WP5 in a molar ratio of 15:1000.

2. The continuous energy transfer light harvesting system of claim 1, wherein, The assembly WP5 The concentration of G in water is greater than 3.2 μΜ.

3. The continuous energy transfer light harvesting system of claim 1, wherein, The concentration of the compound G is 2 x 10 -5 ~2 x 10 -4 M.

4. The continuous energy transfer light harvesting system of claim 3, wherein, The molar ratio of the compound G to the WP5 is 1:0.05 ~ 1:

2.

5. The continuous energy transfer light harvesting system of claim 4, wherein, The molar ratio of the compound G to the WP5 is 1:0.

7.

6. The continuous energy transfer light harvesting system of claim 4, wherein, The WP5 is mixed G and the DBT, the first fluorescence resonance energy transfer occurs, forming the WP5 G / DBT, the fluorescence color gradually changes from cyan to yellow.

7. The continuous energy transfer light harvesting system of claim 6, wherein, The addition of SR101 results in a second FRET event, resulting in WP5 G / DBT / SR101, the fluorescence color changes from yellow to red.

8. A method of preparing a continuous energy transfer light-harvesting system according to any one of claims 1 to 7, characterized in that, The method comprises the following steps: (1) preparing the compound G: The compound 1 shown in formula (IV), 1,5-dibromopentane, K2CO3 and acetone are mixed, heated to reflux, cooled, extracted, dried, filtered, concentrated, purified, and a white solid is obtained, which is the compound 2 shown in formula (III); The compound 2 is mixed with trimethylamine at a molar ratio of 1:10 and dissolved in anhydrous tetrahydrofuran, heated to reflux and stirred for 3 days, during which trimethylamine is added every day, after the reaction is completed, the residue is washed with petroleum ether, ethyl acetate and acetone, and the obtained blue fluorescent solid is the compound G; formula (IV), formula (III); (2) preparing a continuous energy transfer light trapping system: The compound G and the WP5 are dissolved in water at a molar ratio of 1:0.05-1:2 and self-assembled to form a nanometer assembly WP5 emitting cyan fluorescence G; the WP5 G and the DBT are mixed at a molar ratio, and after ultrasonic treatment, a light harvesting system undergoing first fluorescence resonance energy transfer is obtained; the SR101 is continuously added, and after ultrasonic treatment, the light harvesting system undergoing continuous energy transfer is obtained, at which time the WP5 The molar ratio of G, the DBT and the SR101 is 1000:20:1-1000:20:

15.

9. Use of the continuous energy transfer light-harvesting system according to any one of claims 1 to 7 for the production of a luminescent material, characterized in that, The luminescent material is a tunable photoluminescent material, which has a fluorescent adjustable emission band and an excitation wavelength of 340 nm.

10. Use of the continuous energy transfer light harvesting system according to any one of claims 1 to 7 in the field of latent fingerprint imaging, characterized in that, The specific steps are: different WP5 The solution of the continuous energy transfer light trapping system with the ratio of G / DBT / SR101 is concentrated into fluorescent nanoparticles, montmorillonite is added and uniformly mixed, and the fingerprint powder is prepared by drying.

11. Use according to claim 10, characterized in that, High-resolution three-level fingerprint imaging is obtained, including core points, lakes, short ridges, spurs, bifurcations, terminations and sweat pores; fingerprint powder can be used for fingerprint imaging on a material matrix, including plastic, marble, wood, rubber, metal and textiles.

Images