Blue-green light eutectic composite glass material for underwater wireless optical communication and preparation method thereof

Abstract

This invention provides a method for preparing a blue-green eutectic composite glass material for underwater wireless optical communication, specifically including the following steps: Step 1, preparing an aqueous solution of acridine precursor; Step 2, preparing a phosphate glass precursor solution; Step 3, mixing the aqueous solution of acridine precursor and the phosphate glass precursor solution to synthesize an acridine-phosphate organic eutectic composite precursor solution; Step 4, melting and quenching the obtained acridine-phosphate organic eutectic composite precursor to form a eutectic composite glass material; Step 5, cutting and double-sided optically polishing the obtained eutectic composite glass material to obtain a blue-green eutectic composite glass.

Description

Technical Field

[0001] This invention relates to the field of communication materials, and in particular to a blue-green eutectic composite glass material for underwater wireless optical communication and its preparation method. Background Technology

[0002] Underwater wireless optical communication (UWOC) is considered one of the core technologies for future 6G networks and marine exploration due to its significant advantages such as high bandwidth, low latency, good security, and absence of electromagnetic interference. The transmission performance of light waves in water is highly dependent on their wavelength. In 1963, research by Duntley et al. revealed that seawater exhibits minimal attenuation of blue-green light with wavelengths between 460 nm and 540 nm. This band is therefore known as the underwater "blue-green light window" and is an ideal channel for achieving efficient underwater optical transmission.

[0003] Currently, underwater UWOC systems primarily use light-emitting diodes (LEDs) or laser diodes (LDs) as light sources at their transmitters. While LEDs are less expensive, their inherently long spontaneous emission transition lifetime and RC circuit delay severely limit the modulation bandwidth. Furthermore, they suffer from a "sudden efficiency drop" effect, leading to optical output power saturation under high current drive, which restricts communication distance and speed. In contrast, LDs, based on the principle of stimulated emission, possess outstanding advantages such as strong coherence, good directionality, and high power density, making them the preferred light source for achieving high-speed, long-distance, point-to-point underwater optical communication.

[0004] However, III-V semiconductor LDs that directly emit blue-green light (especially InGaN-based LDs) face a severe "green gap" challenge in the "blue-green light window" band. Limited by problems such as quantum well crystal quality degradation, quantum confinement Stark effect, and low carrier injection efficiency, their electro-optic conversion efficiency is generally less than 20%, which restricts their practical application.

[0005] To overcome the aforementioned bottlenecks, "fluorescence conversion" technology has emerged, which utilizes a high-power blue light-emitting diode (LD) to pump fluorescent materials, converting a portion of their blue light into the desired blue-green light. This technological approach combines the high power density of the LD with the tunable emission of the fluorescent material, making it an effective strategy for achieving high-brightness blue-green light sources. Currently, commercially available fluorescence conversion materials utilize rare-earth ions (such as Eu). 2 + Ce 3+ Doped inorganic phosphors (such as β-SiAlON:Eu) 2+ The rare earth elements (Ca3Sc2Si3O12:Ce3+) are the main components. However, the 4f-4f transitions of rare earth ions are parity-forbidden, resulting in fluorescence lifetimes typically ranging from hundreds of nanoseconds to microseconds, which is nearly 10 times shorter than the picosecond response times of pumped LDs. 5The time-domain mismatch of several times severely limits the modulation bandwidth of phosphor-based conversion light sources, making it difficult to meet the requirements of high-speed communication.

[0006] Organic fluorescent materials, due to their allowed π-π* transition mechanism, typically possess excellent properties such as high fluorescence quantum efficiency and rapid radiation decay (nanosecond-level), theoretically better suited to meet high-speed modulation requirements. However, under continuous irradiation by high-power-density lasers, the structures of organic molecules, maintained by weak interactions such as hydrogen bonds and van der Waals forces, are highly susceptible to photodegradation and thermal quenching. Their optical / thermal stability is far inferior to that of inorganic materials, making it difficult to withstand the harsh thermal loads in laser-driven fluorescence conversion scenarios. This has become a core obstacle to their practical application.

[0007] In recent years, significant progress has been made in the "composite glass" strategy, which encapsulates metastable photofunctional crystalline phases (such as quantum dots and perovskites) within rigid inorganic glass matrices to enhance their stability. The glass matrix provides a robust physical barrier and a stable chemical environment, effectively protecting the luminescent centers from external corrosion. This suggests a feasible technological path: if efficient, fast-response organic light-emitting units can be stably immobilized within inorganic glass, it is hoped that the problems of poor stability in organic materials and slow response in inorganic materials can be solved simultaneously. However, achieving uniform and stable dispersion of organic light-emitting molecules within the glass while maintaining their efficient and rapid luminescence characteristics remains a crucial technological challenge to be overcome. Summary of the Invention

[0008] The main objective of this invention is to provide a blue-green eutectic composite glass material for underwater wireless optical communication and its preparation method. The prepared blue-green eutectic composite glass material can realize high-speed underwater communication and high-power lighting.

[0009] To achieve the above objectives, the technical solution adopted by this invention is as follows: a method for preparing a blue-green eutectic composite glass material for underwater wireless optical communication, specifically including the following steps: Step 1: Prepare an aqueous solution of acridine precursor; Step 2: Prepare the phosphate glass precursor solution; Step 3: Mix the acridine precursor aqueous solution with the phosphate glass precursor solution to synthesize the acridine-phosphate organic eutectic composite precursor solution; Step 4: The obtained acridine-phosphoric acid organic eutectic composite precursor is melt-quenched and shaped to obtain eutectic composite glass material; Step 5: Cut and double-sided optically polish the obtained eutectic composite glass material to obtain blue-green eutectic composite glass.

[0010] Preferably, step one specifically includes the following steps: Step 11: Place a certain amount of acridine powder in a certain amount of deionized water to form a mixed solution; Step 12: Heat the mixed solution in a water bath and stir thoroughly for a period of time to obtain a clear aqueous solution of acridine precursor.

[0011] Preferably, step two specifically includes the following steps: Step 21: Take a certain amount of deionized water; Step 22: Add a certain amount of phosphoric acid of a certain concentration to deionized water and stir until homogeneous; Step 23: Add a certain amount of potassium fluoride to the product of step 22 and stir until completely dissolved; Step 24: Add a certain amount of aluminum dihydrogen phosphate to the product of step 23 and stir until a uniform suspension is formed; Step 25: Add zinc oxide to the product of step 24 and stir continuously until homogeneous to obtain a phosphate glass precursor solution, which is a suspension.

[0012] Preferably, step three specifically includes the following steps: Step 31: Take a certain amount of the phosphate glass precursor solution obtained in Step 2 and keep it magnetically stirred. Step 32: Take a certain amount of the acridine precursor aqueous solution obtained in Step 1 and add it dropwise to the acid salt glass precursor solution. During the dropwise addition, a large amount of yellow precipitate is generated. Step 33: During the dropwise addition, observe under a 365 nm UV lamp. When the fluorescence of the mixture changes from the inherent weak blue light of acridine to a bright blue-green fluorescence, it indicates that an acridine-phosphate organic eutectic composite precursor solution has been obtained.

[0013] Preferably, in step 32, the concentration of the acridine precursor aqueous solution is 0.01 mol / L, and the volume ratio of the acridine precursor aqueous solution to the phosphate glass precursor solution is (1-10):10.

[0014] Preferably, step four specifically includes the following steps: Step 41: Transfer the acridine-phosphate organic eutectic composite precursor solution to a ceramic crucible of a certain capacity; Step 42: Place the ceramic crucible into a preheated muffle furnace and keep it warm for a period of time; Step 43: Remove the ceramic crucible from the muffle furnace, immediately press it quickly with another copper plate and quench it to obtain a transparent, yellow-green eutectic composite glass material.

[0015] The present invention also provides a blue-green eutectic composite glass for underwater wireless optical communication, which is prepared by the above-described preparation method.

[0016] The present invention also provides the application of the above-mentioned blue-green eutectic composite glass in wireless optical communication devices.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1) Innovative material design, outstanding performance advantages: This invention precisely constructs acridine-phosphate eutectic luminescent centers through molecular self-assembly at the solution precursor stage, and then directly and uniformly encapsulates them in a rigid matrix using the preparation and molding process of a phosphate glass network. This in-situ encapsulation technology cleverly avoids the problems of luminescent body agglomeration and poor interfacial compatibility in the traditional "synthesis-then-dispersion" process, achieving uniform dispersion and stable immobilization of the luminescent centers in the glass. Moreover, the process is simple, the conditions are mild, and the reproducibility is good.

[0018] 2) Extremely high luminous efficiency and fast response: Thanks to the unique molecular stacking mode of acridine-phosphate eutectic, the material exhibits extremely high fluorescence quantum efficiency (>90%) and ultrafast radiation decay lifetime (28 ns), effectively solving the bottleneck of traditional rare earth phosphors with excessively long lifetime (microsecond level) and slow response caused by parity-forbidden transitions.

[0019] 3) Excellent optical and thermomechanical properties: The glass matrix endows the material with high optical transparency (visible light transmittance > 80% at a thickness of 1 mm), excellent thermal stability (glass transition temperature > 400℃), and a high laser damage threshold (> 90 W / cm²). 2 These characteristics ensure the long-term stability and reliability of the material under high-power laser drive.

[0020] 4) High spectral matching degree, with direct application potential: The material's strong blue-green emission peak is stably located at approximately 480 nm, which highly coincides with the "blue-green light window" (460-540 nm) of seawater. Simultaneously, it is similar to the currently widely used β-SiAlON:Eu... 2+ Compared to commercially available blue-green band rare-earth fluorescent materials, the eutectic composite glass provided by this invention achieves a significant improvement in overall performance. Traditional phosphors or their encapsulants suffer from significant interfacial light scattering, low thermal conductivity, and susceptibility to aging of organic encapsulants, which limit their long-term reliability and light output quality at high power densities. The material of this invention, due to its intrinsic glass morphology, fundamentally avoids these problems, greatly simplifying the manufacturing process from "material" to "device." It not only eliminates the cumbersome powder dispersion and encapsulation steps, reducing encapsulation costs and failure risks, but also improves the structural stability and environmental tolerance of the end device, demonstrating excellent direct application potential.

[0021] 5) Meets the requirements for underwater wireless communication applications: Based on the aforementioned superior performance, the eutectic composite glass of this invention was validated in a simulated underwater communication system. Experiments show that this material can achieve a -3dB modulation bandwidth of 30 MHz under laser drive and exhibits good stability in both surface and underwater communication. This result fully demonstrates that this material can effectively overcome the core contradiction in traditional fluorescence conversion technology where "response speed" and "material stability" are difficult to balance. Its comprehensive performance meets the requirements of underwater wireless optical communication systems for core fluorescence conversion modules, providing key material support for the development of novel wireless underwater optical communication systems integrating long-distance illumination and high-speed data transmission functions. Attached Figure Description

[0022] Figure 1 These are Raman spectra of acridine, phosphate-acridine eutectic, blank glass, and eutectic composite glass; Figure 2 These are the transmission curves of eutectic composite glass and blank glass. Figure 3 This is the excitation / emission spectrum of the eutectic composite glass; Figure 4 This is the absolute quantum efficiency diagram of the eutectic composite glass; Figure 5 This is the fluorescence decay curve of the eutectic composite glass; Figure 6 This is a comparison chart of the laser damage thresholds of eutectic materials and eutectic composite glasses; Figure 7 This is a curve showing the modulation bandwidth of eutectic composite glass in visible light communication in air and water. Figure 8 The comparison shows the fluorescence emission spectra of eutectic composite glasses with different acridine contents; Figure 9 The comparison shows the fluorescence decay curves of eutectic composite glasses with different acridine contents. Figure 10 These are sample photos of eutectic composite glasses prepared at 340℃ and 400℃; Figure 11 The comparison shows the fluorescence emission spectra of eutectic composite glasses obtained at different preparation temperatures; Figure 12 This is a comparison of the fluorescence decay curves of eutectic composite glasses obtained at different preparation temperatures. Detailed Implementation

[0023] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0024] Example 1 A method for preparing a blue-green eutectic composite glass material for underwater wireless optical communication specifically includes the following steps: Step 1: Prepare the acridine precursor aqueous solution, which includes the following steps: Step 11: Add 0.054g of acridine (C 13 H9N) powder was placed in 30 mL of deionized water to form a mixed solution; Step 12: Heat the mixed solution in a 90°C water bath and stir thoroughly for 60 minutes to increase the solubility of acridine in water and obtain a clear aqueous solution of acridine precursor; Step 2: Prepare the phosphate glass precursor solution, which includes the following steps: Step 21: Weigh 20 mL of deionized water into a beaker; Step 22: Add 43.5 mL of phosphoric acid (H3PO4, 85% wt) to the beaker and stir for 10 minutes; Step 23: Add 12.16 g of potassium fluoride (KF) to the product of step 22 and stir until completely dissolved; Step 24: Add 22.19 g of aluminum dihydrogen phosphate (Al(H2PO4)3) to the product of step 23 and stir until a uniform suspension is formed; Step 25: Add 26.76 g of zinc oxide (ZnO) to the product of step 25 and stir continuously for 12 hours to finally obtain a uniform and stable white phosphate glass precursor solution. The phosphate glass precursor solution is a suspension. Step 3: In-situ synthesis of acridine-phosphate organic eutectic composite precursor: Step 31: Measure 10 mL of the phosphate glass precursor solution obtained in Step 2, place it in a beaker, and keep it magnetically stirred. Step 32: Take 7 mL of the acridine precursor aqueous solution obtained in Step 1 and add it dropwise to the beaker in Step 31. During the dropwise addition, a large amount of yellow precipitate is produced. When observed under a 365 nm ultraviolet lamp, the fluorescence of the mixture changes from the weak blue light inherent to acridine to a bright blue-green fluorescence, indicating that an acridine-phosphate organic eutectic composite precursor has been obtained. The acridine-phosphate organic eutectic composite precursor is a suspension.

[0025] Step 4: The obtained acridine-phosphate organic eutectic composite precursor is melt-quenched and shaped to obtain the eutectic composite glass material. Step 41: Transfer the acridine-phosphate organic eutectic composite precursor to a 500 mL ceramic crucible; Step 42: Place the ceramic crucible containing the acridine-phosphate organic eutectic composite precursor into a preheated muffle furnace at 400-500℃ and hold for 30-60 minutes. Step 43: Remove the ceramic crucible from the muffle furnace, immediately press it quickly with another copper plate and quench it to obtain a transparent, yellow-green eutectic composite glass material; Step 5: Remove the obtained eutectic composite glass material from the copper plate and perform double-sided optical polishing to obtain a smooth-surfaced blue-green eutectic composite glass that can be used for optical testing.

[0026] Experimental Example 1 This experimental example is used to test the eutectic composite glass obtained in Example 1.

[0027] 1) Structural characterization of the finished blue-green eutectic composite glass: like Figure 1 As shown, a high-resolution micro Raman spectroscopy (XPLORA PLUS) was used to test the finished blue-green eutectic composite glass, and the Raman spectra of acridine, phosphate-acridine eutectic, blank glass, and eutectic composite glass were compared. Figure 1 As can be seen from the spectrum, the composite glass is a linear superposition of the eutectic characteristic peaks and the glass matrix peaks. This indicates that after the high-temperature melting and quenching process, the structure of the acridine-phosphate eutectic was well preserved in the glass without decomposition, thus achieving stable immobilization of the organic eutectic in the inorganic glass.

[0028] 2) The optical transmittance of the eutectic composite glass was tested: A 1 mm thick eutectic composite glass was tested using a UV-Vis-NIR spectrophotometer (Cary 5000). Figure 2 As can be seen, the eutectic composite glass has an average transmittance of over 80% in the visible to near-infrared band of 470-800 nm, and a very low self-absorption rate at the 483 nm emission peak. This high transparency ensures efficient transmission and output of optical signals within the material.

[0029] 3) The luminescent properties of the eutectic composite glass were tested: 1. Excitation and emission spectra: Measured using a fluorescence spectrometer (Hitachi F-7100), such as... Figure 3 As shown, the eutectic composite glass, when excited by 358 nm ultraviolet light, produces a broadband blue-green emission with a center wavelength of 483 nm, which completely covers the "blue-green low-loss window" (460-540 nm) of seawater.

[0030] 2. Fluorescence quantum efficiency: Tested using an absolute fluorescence quantum yield testing system (Hamamatsu Quantaurus-QYPlus), from... Figure 4 It can be seen that the absolute fluorescence quantum efficiency of the eutectic composite glass is as high as 94.3%, which proves its efficient fluorescence conversion capability.

[0031] 3. Fluorescence lifetime: Fluorescence decay curves were measured using a fluorescence lifetime meter (Hamamatsu Quantaurus-Tau). The average fluorescence lifetime obtained after fitting was 28.52 ns. (See [link to relevant documentation]). Figure 5 This indicates that the composite eutectic glass has a shorter fluorescence lifetime. A shorter fluorescence lifetime means that the luminescent center can respond quickly to the switching of excitation light, which is a key characteristic that supports high-speed optical communication (high modulation bandwidth).

[0032] 4) The laser damage threshold of eutectic composite glass was tested: Under 405 nm continuous laser pumping, the change in luminescence intensity with pump power density was monitored using a fiber optic spectrometer (Ocean Optics QEpro). Figure 6 As can be seen, the laser damage threshold of the eutectic composite glass reaches 90 W / cm². 2 It is worth noting that this value is higher than that of unencapsulated pure acridine-phosphate eutectic powder (approximately 22 W / cm³). 2 The power density is about 4 times higher, which fully demonstrates the excellent protective effect of the inorganic glass matrix on the eutectic luminescence center, enabling it to withstand high power density laser irradiation and meet the application requirements of laser-driven lighting and communication devices.

[0033] 5) Verify the modulation bandwidth and communication of the eutectic composite glass: Using a 405 nm laser modulated with a Bias-Tee as the signal source, the eutectic composite glass was irradiated in air and water, respectively. The resulting blue-green fluorescence signals were received by an avalanche photodiode (APD). Figure 7 As shown, the material's -3 dB electro-optic modulation bandwidth remains stable at approximately 30 MHz in both air and underwater environments. This result directly confirms that the eutectic composite glass can support underwater wireless optical communication and achieve the same level of performance as in air.

[0034] Experimental Example 2 This embodiment aims to investigate the effect of the amount of acridine precursor added on the properties of eutectic composite glass. The preparation steps one, two, four, and five are exactly the same as those in Example 1, except for the synthesis process of the acridine-phosphate organic eutectic composite precursor in step three.

[0035] In this experimental example, step three is as follows: Take 5 portions, each containing 10 mL of the glass precursor solution obtained in step S2, and place them in different small beakers, stirring them magnetically. Add 1 mL, 3 mL, 5 mL, 7 mL, and 10 mL of the acridine precursor aqueous solution obtained in step S1 (i.e., molar amounts of 0.01, 0.03, 0.05, 0.07, and 0.10 mmol) to each of these 5 portions of solution. All eutectic composite glasses immediately produce a yellow precipitate during the addition process and emit bright blue-green fluorescence when observed under a 365 nm ultraviolet lamp.

[0036] Five eutectic composite glasses were obtained in this experiment, and their emission spectra and fluorescence lifetimes were analyzed.

[0037] like Figure 8 As shown, the fluorescence emission peak shapes and positions of the five eutectic composite glasses are basically consistent, with the main peak position remaining stable at approximately 483 nm. This indicates that the change in the amount of acridine precursor added does not alter the intrinsic luminescent energy level structure of the acridine-phosphate eutectic, and the emission spectrum of the prepared eutectic composite glass always effectively covers the low-loss window of blue-green light in seawater.

[0038] like Figure 9 As shown, the fluorescence decay curves of the five eutectic composite glasses all conform to a single exponential decay law, with the fitted fluorescence lifetimes ranging from 25.7 ns to 28.34 ns. This narrow lifetime distribution range demonstrates that, within the molar range of the acridine precursor aqueous solution described in this invention, the obtained eutectic composite glasses possess stable and rapid fluorescence response characteristics, which is fundamental for realizing high-speed modulated optical communication.

[0039] As can be seen from this embodiment, by adjusting the amount of acridine precursor added, the luminescence intensity of the final material can be effectively controlled within a wide range, and near-optimal luminescence intensity can be obtained at a preferred ratio (e.g., a molar amount of 0.07 mmol). This provides flexible space for customizing material properties for different application needs.

[0040] Experiment Example 3 This experimental example aims to investigate the effect of preparation temperature on the properties of eutectic composite glass. Steps one, two, three, and five are identical to those in Example 1, with the only difference being the synthesis process of the eutectic composite precursor in step four. The specific details of step four in this example are as follows: Five portions of the acridine-phosphate organic eutectic composite precursor obtained in step three were taken and transferred to 50 mL ceramic crucibles respectively. The crucibles were then placed in muffle furnaces preheated to 300℃, 320℃, 360℃, 380℃, 400℃, 420℃, and 440℃, and held for 30 minutes respectively. After the heat treatment was completed, the crucibles were quickly removed, pressed rapidly with copper plates, and quenched to obtain seven products.

[0041] In this experiment, seven products were obtained, and their macroscopic morphology and transparency, luminescence properties, and fluorescence lifetime were tested. like Figure 10 As shown, visual and microscopic observation revealed that when the heat treatment temperature was below 380℃, the resulting product was an opaque or translucent sintered body, indicating that the phosphate glass network failed to fully form at this temperature. When the temperature reached 380℃ or higher, the resulting products were all transparent glass bodies with smooth surfaces and uniform internal structures. Furthermore, UV-Vis spectrophotometry showed that glass samples with a thickness of 1 mm prepared at temperatures of 380℃ or higher had a visible light transmittance higher than 80%, which is essentially the same as in Example 1, and can be referred to accordingly. Figure 2 It meets the requirements of optical applications.

[0042] like Figure 11 As shown, the fluorescence emission peaks of all seven products remained stable around 483 nm under 358 nm excitation, exhibiting consistent peak shapes. This indicates that within the stated temperature range, the heat treatment process did not disrupt the luminescent structure of the acridine-phosphate eutectic, and the emission spectra of the products stably covered the blue-green light window of seawater. In contrast, the fluorescence emission peak intensities of the opaque samples (300, 340 °C) were significantly reduced.

[0043] like Figure 12 As shown, the fluorescence decay curves of the seven products all conform to a single exponential decay law. Furthermore, after fitting, their fluorescence lifetime values ​​fluctuate within a narrow range of 26.62 ns to 28.79 ns. This indicates that within the glass formation temperature range of 380-440℃, the seven products exhibit stable and rapid fluorescence response characteristics, which is crucial for realizing high-speed optical modulation communication.

[0044] This experiment tested the effect of heat treatment temperature on the material's structural formation and luminescence properties. The results show that there is a clear critical temperature (approximately 380℃). Below this temperature, transparent glass cannot be obtained, and the material's luminescence properties decrease; above this temperature, optically transparent eutectic composite glass can be stably formed. Within a process window of 380℃ to 440℃, the fluorescence emission peak position (~483 nm) and fluorescence lifetime (~28 ns) of the obtained glass remained basically stable, demonstrating that the preparation method of this invention has good process tolerance to heat treatment temperature. The sample treated at 400℃ exhibited relatively optimal fluorescence intensity. This provides a clear and flexible range for the stable control of process parameters in industrial production, further demonstrating the reliability and practical value of the method of this invention.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A method for preparing a blue-green eutectic composite glass material for underwater wireless optical communication, characterized in that, Specifically, the steps include the following: Step 1: Prepare an aqueous solution of acridine precursor; Step 2: Prepare the phosphate glass precursor solution; Step 3: Mix the acridine precursor aqueous solution with the phosphate glass precursor solution to synthesize the acridine-phosphate organic eutectic composite precursor solution; Step 4: The obtained acridine-phosphoric acid organic eutectic composite precursor is melt-quenched and shaped to obtain eutectic composite glass material; Step 5: Cut and double-sided optically polish the obtained eutectic composite glass material to obtain blue-green eutectic composite glass.

2. The preparation method according to claim 1, characterized in that, Step one specifically includes the following steps: Step 11: Place a certain amount of acridine powder in a certain amount of deionized water to form a mixed solution; Step 12: Heat the mixed solution in a water bath and stir thoroughly for a period of time to obtain a clear aqueous solution of acridine precursor.

3. The preparation method according to claim 1, characterized in that, Step two specifically includes the following steps: Step 21: Take a certain amount of deionized water; Step 22: Add a certain amount of phosphoric acid of a certain concentration to deionized water and stir until homogeneous; Step 23: Add a certain amount of potassium fluoride to the product of step 22 and stir until completely dissolved; Step 24: Add a certain amount of aluminum dihydrogen phosphate to the product of step 23 and stir until a uniform suspension is formed; Step 25: Add zinc oxide to the product of step 24 and stir continuously until homogeneous to obtain a phosphate glass precursor solution, which is a suspension.

4. The preparation method according to claim 1, characterized in that, Step three specifically includes the following steps: Step 31: Take a certain amount of the phosphate glass precursor solution obtained in Step 2 and keep it magnetically stirred. Step 32: Take a certain amount of the acridine precursor aqueous solution obtained in Step 1 and add it dropwise to the acid salt glass precursor solution. During the dropwise addition, a large amount of yellow precipitate is generated. Step 33: During the dropwise addition, observe under a 365 nm UV lamp. When the fluorescence of the mixture changes from the inherent weak blue light of acridine to a bright blue-green fluorescence, it indicates that an acridine-phosphate organic eutectic composite precursor solution has been obtained.

5. The preparation method according to claim 1, characterized in that, Step four specifically includes the following steps: Step 41: Transfer the acridine-phosphate organic eutectic composite precursor solution to a ceramic crucible of a certain capacity; Step 42: Place the ceramic crucible into a preheated muffle furnace and keep it warm for a period of time; Step 43: Remove the ceramic crucible from the muffle furnace, immediately press it quickly with another copper plate and quench it to obtain a transparent, yellow-green eutectic composite glass material.

6. A blue-green eutectic composite glass for underwater wireless optical communication, prepared by the preparation method according to any one of claims 1-5.

7. The application of the blue-green eutectic composite glass according to claim 6 in wireless optical communication devices.

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