Aggregation-induced luminescence material, preparation method and application thereof

Abstract

The present invention discloses an aggregation-induced luminescence material, a preparation method thereof, and an application thereof. The structural formula of the luminescent material is as follows: #imgabs0# This material introduces two tetraphenylethylene (TPE) structures into a fluoroboron dipyrrole dye, and has better aggregation-induced luminescence performance in solution, with a quantum yield of 86%. At the same time, the aggregation-induced luminescence material is introduced into a laser design with whispering gallery properties, thereby improving the energy utilization efficiency of the excitation laser, while significantly reducing the detection threshold and improving the laser stability, thereby realizing a low-threshold organic dye microcavity laser. The system and method of the present invention can also achieve parallel excitation of multiple microbubble cavities by adjusting the laser spot, which has the advantage of achieving multi-wavelength output. And there is no need to pull a tapered optical fiber to introduce pump light, and the device is more robust. The process of the present invention is simple, easy to operate, easy to replace liquid, and has a low production cost, which broadens the application prospects of organic materials in micro-nano lasers, materials, and detection fields.

Description

Technical Field

[0001] The present invention relates to the field of micro-nano optics and material synthesis technology, and in particular to an aggregation-induced luminescence material and a preparation method and application thereof. Background Art

[0002] Whispering Gallery Mode (WGM) lasers utilize total internal reflection (TIR) ​​on the inner surface of a high-refractive-index cavity, allowing light waves to propagate along the microcavity walls with minimal energy dissipation. Consequently, WGM lasers offer advantages such as extremely high quality factor, small mode volume, fast dynamic response, and high sensitivity. These properties facilitate WGM microcavities' applications in single-nanoparticle detection, biosensing, optical communications, and integrated circuits.

[0003] Like traditional lasers, microcavity lasers require a gain medium, a pump source, and a resonant cavity (WGM microcavity). The pump source provides energy to the gain medium, achieving population inversion and lasing. The gain medium material determines the spectral, temporal, and power characteristics of the laser emission. Organic fluorescent dyes are commonly used as gain media in active microcavities. However, traditional organic dyes are subject to aggregation quenching (ACQ). At high concentrations or in aggregated states, strong intermolecular interactions result in only weak emission, severely impacting the dye's gain properties. Literature reports indicate that fluorescein exhibits a tendency to decrease in fluorescence intensity or even complete quenching in the aggregated state. This is detrimental to experimental studies requiring repeated measurements and high pump powers, and can severely limit the performance of microcavity laser devices. Therefore, the choice of gain medium material has a crucial influence on laser performance, determining key parameters such as spectral characteristics, output power, and temporal characteristics. Therefore, researchers are actively exploring new organic gain materials to enhance laser performance and expand their application range.

[0004] Aggregation-induced emission luminogens (AIEs) are a special class of fluorescent molecules that emit little or very weak light in their dissolved state, but emit intense fluorescence when aggregated. AIE dyes offer the advantages of high luminescence efficiency and high doping concentration, without the self-quenching phenomenon that plagues fluorescent dyes at high concentrations or in aggregated states. Therefore, by increasing the concentration of AIE dyes to achieve higher fluorescence intensity, or by reducing the effective concentration due to efficient luminescence in the aggregated state, the aforementioned issues with organic dyes in microcavity lasers can be effectively addressed. For example, patent CN111952827B discloses a bottle-shaped polymer microcavity laser based on AIE dye gain and its preparation method. The method comprises: dripping a dye solution into a polymer fluid to obtain a precursor solution; adding the precursor solution to the thinnest point of a bidirectionally tapered optical fiber to self-assemble a polymer microcavity to form a bottle-shaped microcavity, which is then cured; and coupling another bidirectionally tapered optical fiber to the equatorial plane at the maximum diameter of the bottle-shaped microcavity, encapsulating the resulting microcavity laser. Invention patent CN110676684B discloses a gain material self-aggregation laser and its preparation method. The laser is a polymer microsphere containing a gain material that exists stably in a solution, and a surfactant is distributed on the surface of the microsphere. The concentration of the gain material in the polymer microsphere is higher than the concentration in the solution outside the polymer microsphere, and the gain material does not emit light in the solution, and laser light is achieved in the polymer microsphere. The above method usually adopts a self-assembly method to synthesize microsphere microcavities, and then uses optical fiber coupling to excite laser light. However, this method has major drawbacks. On the one hand, the self-assembly method requires high manufacturing precision, and the tapered optical fiber is fragile and easily damaged during the manufacturing process, which is difficult to manufacture. The formation of the whispering gallery microsphere cavity is relatively difficult and complicated. In addition, each time the organic dye is replaced, the microspheres need to be re-self-assembled, which is inconvenient for experimental operation and reduces practicality. On the other hand, the tapered optical fiber is more susceptible to external interference, resulting in data instability. More importantly, it uses traditional aggregation-induced emission materials with low quantum yield, generally less than 50%. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the technical problems to be solved by the present invention are: providing an aggregation-induced emission material and its preparation method and application, thereby enriching the types and selectivity of existing luminescent materials; the present invention also provides the application of the aggregation-induced emission material in microcavity lasers, thereby solving the problems of existing microcavity lasers such as low quantum yield of luminescent materials, fluorescence quenching (ACQ) of existing gain materials in solid or aggregated states, poor stability, and difficulty in operation.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: an aggregation-induced luminescence material, the structural formula of the luminescent material is as follows:

[0007] Another object of the present invention is to provide a method for preparing the above-mentioned aggregation-induced emission material, the synthesis route of which is as follows:

[0008]

[0009] The following steps are involved:

[0010] S1: Compound 1 and N-iodosuccinimide were dissolved in CH2Cl2 solvent, and the reaction solution was stirred at room temperature until the raw material was completely consumed as monitored by TLC analysis. After the reaction was completed, the mixture was concentrated in vacuo and the obtained solid was separated by column chromatography to obtain the red intermediate compound 2.

[0011] S2: Compound 2 and 4-(1,2,2-triphenylvinyl)phenylboronic acid are placed in a tetrahydrofuran solvent, and then tetrakis(triphenylphosphine)palladium and K2CO3 are added in sequence to obtain a reaction solution, and then the reaction solution is placed in an inert gas environment for reaction and stirred overnight. After the reaction is completed, the reaction solution is quenched with H2O and extracted with CH2Cl2, and then dried to remove the solvent. The obtained solid is purified by silica gel column chromatography to obtain compound 3, which is the aggregation-induced emission material.

[0012] Preferably, the molar ratio of compound 1 to N-iodosuccinimide in step S1 is 1:1 to 1:2.5.

[0013] Preferably, the molar ratio of compound 2 and 4-(1,2,2-triphenylvinyl)phenylboronic acid in step S2 is 1:2 to 1:4; the molar ratio of tetrakis(triphenylphosphine)palladium to K2CO3 is 1:50 to 1:300.

[0014] Preferably, the reaction temperature in step S2 is 70-90° C., and the reaction time is 24-48 hours; and the inert gas is nitrogen or argon.

[0015] Preferably, the eluent in the column chromatography is cyclohexane / dichloromethane, and the volume ratio of cyclohexane to dichloromethane is 4 to 10:1.

[0016] Another object of the present invention is to provide an application of the above-mentioned aggregation-induced emission material in microcavity laser detection.

[0017] Another object of the present invention is to provide a method for preparing a microcavity laser, comprising the following steps:

[0018] 1) Selecting a section of capillary quartz microtube, and preparing a microbubble cavity with a nearly spherical structure on the capillary quartz microtube by melt blowing, wherein the microbubble cavity is a hollow structure with left and right ends open, thereby obtaining a microbubble cavity device;

[0019] 2) The aggregation-induced emission material is dissolved in a mixed solution of PBS and DMSO to obtain an aggregation-induced emission material solution for later use; the aggregation-induced emission material may also be an aggregation-induced emission material with other structures.

[0020] 3) fixing both ends of one or more microbubble cavity devices prepared in step 1) on a glass slide, then placing the glass slide on a three-dimensional adjustment frame, connecting one end of the microbubble cavity device to a spectrometer via an optical fiber, and the other end to a syringe via a Teflon tube, and slowly injecting the aggregation-induced luminescence solution prepared in step 2) through the syringe until the solution fills the entire microbubble cavity and no air bubbles are left;

[0021] 4) The pump light source is adjusted to focus the output light of the pump light source into the microbubble cavity through a reflector and a focusing lens. The laser signal output by the microbubble cavity is collected and presented as a spectral signal by an optical fiber spectrometer by adjusting a certain angle, thereby obtaining the microcavity laser.

[0022] Preferably, the concentration of the aggregation-induced emission material solution is 1 mM to 10 mM.

[0023] Another object of the present invention is to provide a microcavity laser prepared by the above method.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. This invention provides a novel aggregation-induced emission (AIE) material. This material incorporates two tetraphenylethylene (TPE) structures into a fluoroboron dipyrrole dye (BODIPY). Due to the AIE properties of the dual TPEs, the resulting material exhibits improved AIE performance in solution, with a quantum yield of 86%, surpassing traditional AIE materials. This material exhibits excellent biocompatibility and high fluorescence quantum yield, making it an excellent choice for gain media. It is of great significance in expanding the scope of organic micro-nanolasers in the materials and detection fields.

[0026] 2. This invention incorporates aggregation-induced emission dyes as the laser gain medium in a whispering gallery laser design. During the preparation process, the aggregation-induced emission material is directly injected into a self-made microbubble cavity. Pump light is focused into the microbubble cavity using a reflector and focusing lens to obtain a laser spectrum. This system and method improves the energy efficiency of the excitation laser while significantly enhancing laser stability, realizing a low-threshold organic dye microcavity laser. Furthermore, it eliminates the need for tapered optical fibers to introduce pump light, integrating the laser with the pump system for greater robustness. The present invention also enables parallel excitation of multiple microbubble cavities by adjusting the laser spot, offering the advantage of achieving multi-wavelength output. The present invention offers a simple process, simplified operation, easy replacement of organic dye solutions, and low production cost. It overcomes the drawback of fluorescence quenching (ACQ) of traditional fluorescent materials in the solid or aggregated state. This method also provides a new approach and a practical technical solution for the application of microcavity laser technology in high-sensitivity sensor research, broadening the application prospects of organic materials in micro-nano lasers, materials, and detection, and significantly promoting the application of organic micro-nano laser materials in chemical sensing and biology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the mass spectrum of the aggregation-induced emission material of the present invention.

[0028] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum of the aggregation-induced emission material of the present invention.

[0029] Figure 3 It is the aggregation-induced emission characteristic of the aggregation-induced emission material of the present invention.

[0030] Figure 4 Schematic diagram of the microcavity laser device of the present invention.

[0031] Figure 5 Flow chart of the preparation of the microcavity device of the present invention.

[0032] Figure 6 This is the laser spectrum diagram of the microcavity laser of the present invention.

[0033] Figure 7 Schematic diagram of the multi-wavelength output device of the microcavity laser of the present invention.

[0034] Figure 8 Graphs showing different laser emission spectra of multi-wavelength outputs of the microcavity laser of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described in detail below with reference to the examples. The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, etc. used in the following examples are all commercially available unless otherwise specified.

[0036] Example 1

[0037] A preparation process route of an aggregation-induced emission material is as follows:

[0038] S1: Compound 1 (300 mg, 0.93 mmol) and excess N-iodosuccinimide NIS (837 mg, 3.72 mmol) were dissolved in anhydrous CH2Cl2 (40 mL) solvent, and the mixture was stirred at room temperature for about 30 min and monitored by TLC until the starting material was completely consumed. After the reaction was completed, the reaction product was concentrated in vacuo, and the crude product was purified by column chromatography with cyclohexane / dichloromethane (v / v) = 4:1 eluent to obtain red solid compound 2 (450 mg, yield 84.0%).

[0039] S2: Compound 2 (310 mg, 0.69 mmol) and 4-(1,2,2-triphenylvinyl)phenylboronic acid (285 mg, 0.76 mmol) were placed in a tetrahydrofuran aqueous solvent (including 16 mL THF and 4 mL H2O), and tetrakis(triphenylphosphine)palladium (31 mg, 0.026 mmol) and K2CO3 (1.2 g, 8.6 mmol) were added in sequence to obtain a reaction solution. The reaction solution was then placed under nitrogen protection and heated to 80±1°C for 48 h. After the reaction, the mixture was quenched with H2O (20 mL) and extracted three times with CH2Cl2. The solvent was then dried over anhydrous Na2SO4, and the solvent was removed in vacuo. The residue was purified by column chromatography with cyclohexane / dichloromethane (v / v) = 4:1 as an eluent to obtain the aggregation-induced emission material, i.e., compound 3 (232 mg, yield 50.6%).

[0040] 1. The aggregation-induced emission material prepared in this example was subjected to mass spectrometry and nuclear magnetic resonance hydrogen spectrum analysis. The results are as follows: Figure 1 and Figure 2 The specific data is as follows:

[0041] 1 HNMR (400MHz, CDCl3) 7.51 (s, 3H), 7.35-7.34 (m, 2H), 7.16-7.03 (m, 36H), 6.91-6.89 (d, 2H), 2.52 (s, 6H), 1.59 (s, 6H).

[0042] The molecular formula of the luminescent material obtained by the present invention is C71 H 57 BF2N2, the structural formula is as follows:

[0043]

[0044] 2. Compound 3 prepared in this example was added to a mixed solution of PBS and DMSO to a concentration of 10 μM. Then, the aggregation-induced emission characteristics were detected by changing the ratio of PBS to DMSO solvents. The volume ratios of PBS to DMSO were 1:9, 3:7, 4:6, 1:1, 2:1, 3:1, 4:1, 9:1 and 99:1, respectively. The results are shown in FIG. Figure 3 shown.

[0045] As can be seen from the figure, under an excitation wavelength of 380 nm, the fluorescence intensity of compound 3 in the aqueous phase increases significantly with increasing PBS content, exhibiting typical AIE characteristics, demonstrating that the luminescent material of the present invention exhibits good aggregation-induced emission properties in solution. Using the following formula, the quantum yield of the aggregation-inducing material of the present invention is calculated to be 86%.

[0046] φ X =φ st (Grad X / Grad st )(η X 2 / η st 2 )

[0047] Where "Φ" represents the fluorescence quantum yield, "Grad" represents the slope of the ratio of the integral of the fluorescence intensity area to the corresponding absorbance value, and "η" represents the refractive index of the solution. The subscripts "st" and "X" represent the standard solution and the test solution, respectively.

[0048] Example 2

[0049] A microcavity laser based on aggregation-induced emission materials includes a microbubble cavity device, an aggregation-induced emission gain material, and an excitation light system. The schematic diagram of the device is shown in FIG. Figure 4 As shown, it includes a laser pump source 1, a reflector 2, an optical focusing objective lens 3, an imaging CCD 4, a microbubble cavity device 5 and a fiber optic spectrometer 6.

[0050] The method for preparing the microcavity laser based on aggregation-induced emission material comprises the following steps:

[0051] 1) If Figure 5As shown, take a capillary quartz tube, connect one end to a syringe, burn off the coating on the surface of the capillary quartz tube with an alcohol burner, and wipe the capillary quartz tube clean with alcohol dipped in clean paper, melt and seal the other end of the capillary quartz tube with the help of an optical fiber fusion splicer, adjust the position of the capillary quartz tube in the fusion splicer, ensure that both ends of the position where microbubbles are formed have appropriate lengths, then slowly push the syringe while discharging, until the position of the discharge forms a symmetrical and rounded microbubble with a nearly spherical structure, and obtain a microbubble cavity. The two ends of the obtained microbubble cavity use ultraviolet glue to connect Teflon tubes, which is convenient for injecting liquid. And it has good air tightness. After the liquid is injected from one end Teflon tube, there is no leakage, that is, the liquid can flow smoothly from the water injection port to the water outlet, and obtain a microbubble cavity device 5.

[0052] 2) 0.01 g of the aggregation-induced emission solid material prepared in Example 1 was dissolved in 0.1 mL of a mixed solution of PBS and DMSO to obtain an aggregation-induced emission material solution.

[0053] 3) Fixing both ends of the microbubble cavity device 5 prepared in step 1) on a glass slide, placing the glass slide on a three-dimensional adjustment frame, connecting one end of the microbubble cavity device to a fiber optic spectrometer 6 via an optical fiber, and connecting the other end to a syringe via a Teflon tube, and then slowly injecting the aggregation-induced luminescence solution prepared in step 2) using a syringe until the solution enters and gradually fills the entire microbubble cavity, and observing the entire whispering gallery microbubble cavity using a microscope and CCD 4 to ensure that there are no air bubbles.

[0054] 4) The output light of the laser pump source 1 can be focused into the microbubble cavity of the microbubble cavity device through the reflector 2 and the optical focusing lens 3. The laser signal output by the microbubble cavity is collected and presented as a spectral signal by the optical fiber spectrometer by adjusting a certain angle, thereby obtaining the microcavity laser.

[0055] When implementing it specifically, Figure 4 As shown, the 532nm pulse excitation light source laser pump source 1 in the obtained microcavity laser is turned on, and the pump light is coupled into the optical focusing lens 3 through the reflector 2. The light spot is then focused in the microbubble cavity of the microbubble cavity device 5, and the energy of the laser pump source 1 excitation is adjusted so that the microfluidic microcavity laser can achieve stable output of whispering gallery laser at a low threshold. The laser emitted from the microbubble cavity is directly collected by optical fiber by finding a certain laser emission angle, and then transmitted to the optical fiber spectrometer 6 to display the spectral information, thereby obtaining a section of the whispering gallery laser spectrum. The result is shown in FIG. Figure 6 As shown. Figure 6 As can be seen, the central wavelength of the laser output by the microcavity laser in this embodiment is around 600nm and can be output stably. The microcavity laser of the present invention significantly improves laser stability and energy utilization efficiency of the excited laser, thus realizing a low-threshold organic dye microcavity laser.

[0056] Furthermore, in a specific implementation, a plurality of capillary quartz tubes with microbubble cavities are prepared, as above, Figure 7 The microbubble cavity device 1 and the microbubble cavity device 2 are shown, and then the microbubble cavity device 1 and the microbubble cavity device 2 are arranged in parallel and their two ends are fixed on the same glass slide. A 0.1 mg / ml rhodamine B solution is injected into the microbubble cavity device 1, and a 0.1 mg / ml aggregation-induced emission material solution prepared in the present invention is injected into the microbubble cavity device 2. The angle of the lens can be adjusted independently by the built reflector, that is, the position of the pump laser spot can be precisely controlled by adjusting the reflector, so that the regulated pump laser spot is focused in different microbubble cavities in the microbubble cavity device. By finding a certain laser emission angle, the laser light is directly collected using an optical fiber, and then transmitted to a fiber optic spectrometer for display of the spectral information to obtain the whispering gallery laser spectrum. The results are shown as follows. Figure 8 As shown, this embodiment simultaneously obtains two different laser emission spectra ( Figure 8 A is the spectrum of Rhodamine B, Figure 8 B is the spectrum of compound 3), and the laser intensity generated by the aggregation-induced emission material of the present invention has obvious advantages, indicating that the present invention can conveniently and quickly realize simultaneous excitation of multiple materials and simultaneous output of multiple wavelengths.

[0057] The above description is only a preferred embodiment of the present invention and does not limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Application of an aggregation-induced emission material in microcavity laser detection, wherein the structural formula of the aggregation-induced emission material is as follows: 。 2. A method for preparing a microcavity laser, characterized in that: The following steps are involved: 1) Selecting a section of capillary quartz microtube, and preparing a microbubble cavity with a nearly spherical structure on the capillary quartz microtube by melt blowing, wherein the microbubble cavity is a hollow structure with left and right ends open, thereby obtaining a microbubble cavity device; 2) dissolving the aggregation-induced emission material according to claim 1 in a mixed solution of PBS and DMSO to obtain an aggregation-induced emission material solution, and setting it aside; 3) Fixing both ends of one or more microbubble cavity devices prepared in step 1) on a glass slide, then placing the glass slide on a three-dimensional adjustment frame, connecting one end of the microbubble cavity device to a syringe via Teflon tubing, and slowly injecting the aggregation-induced luminescence solution prepared in step 2) through the syringe until the solution fills the entire microbubble cavity and no air bubbles are left; 4) The pump light source is adjusted to focus the output light of the pump light source into the microbubble cavity of the microbubble cavity device through a reflector and a focusing lens. The laser signal output by the microbubble cavity is collected by a fiber spectrometer and presented as a spectral signal, thereby obtaining the microcavity laser.

3. The method for preparing a microcavity laser according to claim 2, wherein: The concentration of the aggregation-induced emission material solution is 1 mM to 10 mM.

4. A microcavity laser prepared by the method according to claim 2 or 3.

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