A 9-methylacridine eutectic phosphor, its preparation method and application

Abstract

A 9-methylacridine eutectic phosphor, its preparation method, and its applications are disclosed, relating to the field of optoelectronic devices. The chemical formula of this material is MeIPA-MeAD. Its preparation method involves dissolving 9-methylacridine and 5-methylisophthalic acid in an organic solvent, followed by rapid crystallization at room temperature to obtain a highly crystalline phosphor. The advantage of this invention lies in selecting 9-methylacridine and 5-methylisophthalic acid to form a new eutectic material, optimizing the spatial arrangement of the 9-methylacridine chromophore molecules, and improving its luminescence efficiency and stability. Therefore, this eutectic phosphor has advantages such as simple synthesis, high purity, high yield, and high stability. Under 365 nm light excitation at room temperature, it exhibits long-lifetime bright green fluorescence emission. This material shows promising applications in optoelectronic devices, light-emitting diodes, and antibacterial biomaterials.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic devices, specifically to a 9-methylacridine eutectic phosphor, its preparation method, and its application. Background Technology

[0002] PC-LEDs are the core of solid-state lighting, and their performance depends on the outer phosphor material. The phosphor absorbs the emitted light from the internal ultraviolet / blue LED chip and converts it into white light or other colors. Therefore, the luminous efficiency, stability, and tunability of the phosphor material are crucial.

[0003] However, traditional phosphor materials (such as organic dyes and metal complex fluorophores) are generally limited by the aggregation-induced quenching (ACQ) effect, which severely restricts their application expansion. In the aggregated state environment required by solid-state devices, the molecules of these materials are prone to π-π stacking, causing excited-state energy to dissipate through non-radiative transitions, ultimately making it difficult for the external quantum efficiency (EQEs) in solid-state configurations to exceed 30%. More importantly, the ACQ effect is exacerbated by increasing material fill density, failing to meet the requirements of high-power, high-brightness PC-LEDs for high-fill-density light conversion materials. Therefore, developing novel light conversion materials with excellent ACQ resistance has become an urgent need in this field.

[0004] In 2001, Academician Tang Benzhong proposed the concept of aggregation-induced emission (AIE), providing a disruptive technological paradigm for solving the ACQ (acupuncture-induced emission) problem. AIE luminescent materials (AIEgens) possess unique photophysical properties: in solution, they emit almost no light due to intense intramolecular free motion, while in aggregated or solid states, restricted intramolecular motion (RIM) significantly suppresses nonradiative transitions, resulting in a substantial increase in luminescence intensity. This characteristic perfectly matches the application requirements of solid-state light conversion materials, overturning the traditional understanding that aggregation of luminescent materials leads to quenching. After more than two decades of development, AIE materials have made breakthroughs in multiple fields such as optoelectronic displays, biosensors, and stimulus-responsive materials, especially providing a new approach for the research and development of light conversion materials for solid-state lighting. However, most AIEgens rely on complex multi-step covalent synthesis, which involves cumbersome steps, high costs, difficulty in scaling up, and low flexibility in molecular structure control, hindering their industrial application in the PC-LED field.

[0005] Supramolecular co-crystallization can address these issues to some extent. The core of supramolecular co-crystallization is the use of directional non-covalent interactions such as hydrogen bonds, π-π stacking, and van der Waals forces to assemble modular solid materials with programmable optoelectronic properties. Precise bandgap engineering can be achieved through donor-acceptor orbital hybridization. Furthermore, solution processing is possible without covalent modification, and the emission wavelength, quantum yield, and stimulus responsiveness of the material can be programmably controlled, offering significant advantages such as low cost, easy scalability, and designable structure. However, research on aggregation-induced emission of co-crystallized materials is currently extremely limited. Summary of the Invention

[0006] This invention provides a 9-methylacridine eutectic phosphor, its preparation method, and its application. The 9-methylacridine eutectic phosphor can be rapidly prepared by a simple room temperature crystallization method. It exhibits extremely weak luminescence in solution, but its efficiency is significantly enhanced in the aggregated or solid state. This provides a new approach and technology for developing phosphors with high luminous efficiency and high stability required for PC-LED lighting devices.

[0007] To achieve the above objectives, the specific solution adopted by the present invention is as follows: a method for preparing 9-methylacridine co-crystal phosphor, wherein 5-methylisophthalic acid and 9-methylacridine are dissolved in an organic solvent at a molar ratio of 1:1-2, and allowed to stand at room temperature to obtain a co-crystal product; the co-crystal product is then ground to obtain the 9-methylacridine co-crystal phosphor.

[0008] As a further optimization of the above technical solution, the specific process of dissolving 5-methylisophthalic acid and 9-methylacridine in an organic solvent includes: dissolving 5-methylisophthalic acid in an organic solvent to obtain a 5-methylisophthalic acid solution, dissolving 9-methylacridine in an organic solvent to obtain a 9-methylacridine solution, and mixing the 5-methylisophthalic acid solution and the 9-methylacridine solution; or, dissolving 5-methylisophthalic acid in an organic solvent to obtain a 5-methylisophthalic acid solution, and adding 9-methylacridine to the 5-methylisophthalic acid solution.

[0009] As a further optimization of the above technical solution, the organic solvent is anhydrous ethanol, methanol, or acetonitrile.

[0010] As a further optimization of the above technical solution, the settling time is 10-100 min and the grinding time is 2-10 min.

[0011] A 9-methylacridine eutectic phosphor prepared by the above preparation method.

[0012] Application of a 9-methylacridine eutectic phosphor in the fabrication of lighting devices.

[0013] As a further optimization of the above technical solution, 9-methylacridine eutectic phosphor is mixed evenly with an adhesive to obtain a fluorescent adhesive; the fluorescent adhesive is coated on an LED chip, and the adhesive is heated to cure, thereby obtaining a lighting device, wherein the adhesive is epoxy resin or silicone gel.

[0014] As a further optimization of the above technical solution, the driving current of the lighting device is 20-100 mA.

[0015] As a further optimization of the above technical solution, the LED chip has an emission wavelength of 365 nanometers.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. This invention uses 9-methylacridine and 5-methylisophthalic acid to prepare a eutectic phosphor, which transforms the covalent bond design of materials with aggregation-induced emission properties into a non-covalent bond design of molecular assembly design, simplifies the molecular structure, realizes the modular construction of solid materials, and provides a new path for solid-state luminescent materials.

[0018] 2. This invention can rapidly self-assemble and crystallize in solution at room temperature. The reaction time is short, the conditions are mild, no high temperature and high pressure are required, the energy consumption is extremely low, the operation is simple, and the equipment requirements are low. It is highly crystalline and does not require a complicated purification process. Moreover, the material itself is composed only of C, H, N and O elements and does not contain precious metals or rare earth elements, which meets the requirements of sustainable development. In addition, its fluorescence lifetime is long, up to 39.36 ns.

[0019] 3. The 9-methylacridine eutectic phosphor prepared by this invention has AIE characteristics, exhibiting high luminescence intensity and stable quantum yield in the aggregated / solid state. The prepared optoelectronic devices show a strict linear relationship in luminescence intensity under a driving current of 10-100 mA, and can maintain stable performance within the operating range without efficiency roll-off, high color fidelity, and longer lifespan.

[0020] 4. This invention combines 9-methylacridine and 5-methylisophthalic acid, where 9-methylacridine accepts electrons and 5-methylisophthalic acid provides electrons; the specific methyl substitutions of both are precisely controlled from both electronic and spatial dimensions, ultimately creating a supramolecular crystal with the desired luminescent properties.

[0021] The substitution of the methyl group at the 9th position in 9-methylacridine is crucial. It can fine-tune the electron cloud density of acridine through inductive effects, thereby altering its frontier orbital energy level. Simultaneously, this methyl group introduces moderate steric hindrance, helping to prevent fluorescence quenching caused by excessively close molecular packing and potentially inducing more favorable luminescent molecular orientations. The two carboxyl groups of 5-methylisophthalic acid are located at the meta position on the benzene ring, allowing for various flexible coordination modes and facilitating the formation of extended hydrogen bond networks. Its carboxyl groups are strong proton donors, enabling precise bonding with the nitrogen atom of 9-methylacridine. The methyl group at the 5th position (the meta position of the two carboxyl groups), located at the distal end of the benzene ring, primarily plays a steric regulating role. It can slightly adjust the orientation of the benzene ring and the extension direction of the carboxyl groups, optimizing the spatial packing with 9-methylacridine. Furthermore, its hydrophobicity helps guide specific packing patterns during crystallization. Attached Figure Description

[0022] Figure 1 A diagram showing the hydrogen bonds and π-π stacking forces between 5-methylisophthalic acid and 9-methylacridine;

[0023] Figure 2 The simulation results of 9-methylacridine cocrystal phosphor and its corresponding PXRD pattern are shown. The black line represents the result obtained from the simulation of the cocrystal phosphor crystal data, and the red line represents the diffraction peak data observed by powder X-ray diffraction analysis.

[0024] Figure 3 Fourier transform infrared spectrum of 9-methylacridine eutectic phosphor;

[0025] Figure 4 The fluorescence spectrum characterization of 9-methylacridine phosphor is shown below; (a) fluorescence emission spectrum of 9-methylacridine phosphor under excitation by a 365 nm light source, (b) fluorescence decay curve of 9-methylacridine phosphor with a fitted lifetime of 39.36 nanoseconds.

[0026] Figure 5 The luminescence phenomenon of 9-methylacridine eutectic phosphor lighting device under the action of current; (a) the change of its emission spectrum with the increase of driving current; (b) the relationship between its peak intensity and current under different currents and the corresponding linear fitting results; (c) the luminescence images of eutectic phosphor lighting device under different currents.

[0027] Figure 6 Scanning electron microscope image of 9-methylacridine eutectic phosphor;

[0028] Figure 7X-ray photoelectron spectra of 9-methylacridine eutectic phosphor; (a) full X-ray photoelectron spectrum, (b) C 1s spectrum in X-ray photoelectron spectrum, (c) O 1s spectrum in X-ray photoelectron spectrum, (d) N 1s spectrum in X-ray photoelectron spectrum. Detailed Implementation

[0029] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. Parts not described or disclosed in detail in the following embodiments of the present invention should be understood as prior art known or should be known by those skilled in the art.

[0030] A method for preparing a 9-methylacridine (MeAD) eutectic phosphor involves dissolving 5-methylisophthalic acid (MeIPA) and 9-methylacridine in an organic solvent at a molar ratio of 1:1-2, allowing the solution to stand at room temperature for 10-100 min, and obtaining a eutectic product through self-assembly of 5-methylisophthalic acid and 9-methylacridine; grinding the eutectic product for 2-10 min to obtain the 9-methylacridine eutectic phosphor (MeIPA-MeAD).

[0031] The specific process of dissolving 5-methylisophthalic acid and 9-methylacridine in an organic solvent includes:

[0032] 5-Methylisophthalic acid was dissolved in an organic solvent to obtain a 5-methylisophthalic acid solution, and 9-methylacridine was dissolved in an organic solvent to obtain a 9-methylacridine solution. The 5-methylisophthalic acid solution and the 9-methylacridine solution were then mixed.

[0033] Alternatively, 5-methylisophthalic acid can be dissolved in an organic solvent to obtain a 5-methylisophthalic acid solution, and 9-methylacridine can be added to the 5-methylisophthalic acid solution.

[0034] The organic solvent is anhydrous ethanol, methanol, or acetonitrile.

[0035] The self-assembly of 9-methylacridine and 5-methylisophthalic acid in this invention is mainly driven by two interactions: hydrogen bonding and π-π stacking. The hydrogen bonding primarily involves the carboxyl group of 5-methylisophthalic acid acting as a proton donor, forming a hydrogen bond with the nitrogen atom of the acridine ring of 9-methylacridine as a proton acceptor. Weak hydrogen bonds formed between the CH bonds on the aromatic ring or methyl group of 9-methylacridine and the O atoms of the carboxyl group of 5-methylisophthalic acid serve as auxiliary hydrogen bonds. The π-π stacking involves the parallel alignment of the aromatic plane of 9-methylacridine with the benzene ring plane of 5-methylisophthalic acid. The entire self-assembly process is spontaneous. When the two molecules meet in a suitable solvent, they first recognize and combine through the strongest hydrogen bonds, forming dimers or chain structures. Subsequently, these units extend further in three-dimensional space through π-π stacking and auxiliary hydrogen bonds, ultimately forming an ordered co-crystalline solid.

[0036] like Figure 1 The diagram shows the hydrogen bonds and π-π stacking forces between 5-methylisophthalic acid and 9-methylacridine. Figures a and b show the assembly diagrams of 9-methylacridine and 5-methylisophthalic acid from different perspectives. According to the internationally accepted color scheme in the field of chemistry, red represents oxygen atoms, blue represents nitrogen atoms, and yellow-green represents hydrogen bonds and π-π stacking forces.

[0037] The present invention also discloses the application of the above-mentioned 9-methylacridine eutectic phosphor in the preparation of lighting devices. The specific method is as follows: the 9-methylacridine eutectic phosphor is mixed evenly with an adhesive to obtain a fluorescent adhesive; the fluorescent adhesive is coated on an LED chip with an emission wavelength of 365 nanometers, and the adhesive is heated to cure the adhesive to obtain a lighting device, wherein the adhesive is an epoxy resin or an organosilicon gel.

[0038] Example 1

[0039] A method for preparing a 9-methylacridine eutectic phosphor includes the following steps:

[0040] 1. Weigh 0.5 mmol of 5-methylisophthalic acid and 0.5 mmol of 9-methylacridine for later use.

[0041] 2. Dissolve the above-mentioned 5-methylisophthalic acid in 2 mL of anhydrous ethanol and gently shake at room temperature for about 1 min to obtain a clear 5-methylisophthalic acid ethanol solution; similarly, dissolve 9-methylacridine in another 2 mL of anhydrous ethanol and gently shake for about 1 min to obtain a clear 9-methylacridine ethanol solution.

[0042] 3. Pour the 5-methylisophthalic acid ethanol solution into the 9-methylacridine ethanol solution. After mixing, an orange-yellow solution system is obtained. The system is allowed to stand at room temperature (~25 °C) without any stirring or external energy input. The solution system rapidly self-assembles through supramolecular synergistic effects between 5-methylisophthalic acid and 9-methylacridine molecules. After standing for about 2 minutes, tiny orange-yellow crystals are observed precipitating at the bottom of the flask, confirming rapid nucleation during the co-crystallization process. Within 10 minutes, the crystals cover about half of the bottom area of ​​the flask. Within 20 minutes, the crystals cover about two-thirds of the bottom area, and the crystal size continues to increase. After standing for 30 minutes, the reaction is complete, yielding an orange-yellow, blocky co-crystallized product. The obtained co-crystallized product is ground in an agate mortar for 2 minutes to obtain a fine, uniform yellow fluorescent powder, which is the co-crystallized fluorescent powder.

[0043] Example 2

[0044] A method for preparing a 9-methylacridine eutectic phosphor includes the following steps:

[0045] 1. Weigh 0.5 mmol of 5-methylisophthalic acid and dissolve it in 4 mL of anhydrous ethanol. Shake gently at room temperature for about 1 min to obtain a clear 5-methylisophthalic acid ethanol solution.

[0046] 2. Weigh 0.5 mmol of 9-methylacridine and dissolve it in the above 5-methylisophthalic acid ethanol solution. Shake gently for about 1 min to obtain an orange-yellow solution system.

[0047] 3. The solution system was allowed to stand at room temperature (~25 °C) without any stirring or external energy input. Through supramolecular synergistic effects between 5-methylisophthalic acid and 9-methylacridine molecules, the system rapidly self-assembled. After standing for approximately 2 minutes, tiny orange-yellow crystals were observed precipitating at the bottom of the flask, confirming rapid nucleation during the co-crystallization process. Within 10 minutes, the crystals covered approximately half of the bottom area of ​​the flask; within 20 minutes, the crystals covered approximately two-thirds of the bottom area, and the crystal size continued to increase; after 30 minutes, the reaction was complete, yielding an orange-yellow, blocky co-crystallized product. The co-crystallized product was collected by filtration, washed with a small amount of ethanol, and dried at room temperature. The obtained co-crystallized product was ground in an agate mortar for 2 minutes to obtain a fine, uniform yellow fluorescent powder, which is the 9-methylacridine co-crystallized fluorescent powder.

[0048] Example 3

[0049] A method for preparing a 9-methylacridine eutectic phosphor includes the following steps:

[0050] 1. Weigh 0.5 mmol of 5-methylisophthalic acid and 0.75 mmol of 9-methylacridine for later use.

[0051] 2. Dissolve the above-mentioned 5-methylisophthalic acid in 2 mL of anhydrous ethanol and gently shake at room temperature for about 1 min to obtain a clear 5-methylisophthalic acid ethanol solution; similarly, dissolve 9-methylacridine in another 2 mL of anhydrous ethanol and gently shake for about 1 min to obtain a clear 9-methylacridine ethanol solution.

[0052] 3. Pour the ethanol solution of 5-methylisophthalic acid into the ethanol solution of 9-methylacridine, and after mixing, an orange-yellow solution system is obtained. Let it stand at room temperature of ~25 °C without any stirring or external energy input. The solution system rapidly self-assembles through supramolecular synergistic effects between 5-methylisophthalic acid and 9-methylacridine molecules. After standing for 30 min, the reaction is complete, and an orange-yellow, blocky co-crystallized product is obtained. Grind the obtained co-crystallized product in an agate mortar for 2 min to obtain a fine and uniform yellow fluorescent powder, which is the co-crystallized fluorescent powder.

[0053] Example 4

[0054] A method for preparing a 9-methylacridine eutectic phosphor includes the following steps:

[0055] 1. Weigh 0.5 mmol of 5-methylisophthalic acid and 1 mmol of 9-methylacridine for later use.

[0056] 2. Dissolve the above-mentioned 5-methylisophthalic acid in 2 mL of anhydrous ethanol and gently shake at room temperature for about 1 min to obtain a clear 5-methylisophthalic acid ethanol solution; similarly, dissolve 9-methylacridine in another 2 mL of anhydrous ethanol and gently shake for about 1 min to obtain a clear 9-methylacridine ethanol solution.

[0057] 3. Pour the ethanol solution of 5-methylisophthalic acid into the ethanol solution of 9-methylacridine, and after mixing, an orange-yellow solution system is obtained. Let it stand at room temperature of ~25 °C without any stirring or external energy input. The solution system rapidly self-assembles through supramolecular synergistic effects between 5-methylisophthalic acid and 9-methylacridine molecules. After standing for 30 min, the reaction is complete, and an orange-yellow, blocky co-crystallized product is obtained. Grind the obtained co-crystallized product in an agate mortar for 2 min to obtain a fine and uniform yellow fluorescent powder, which is the co-crystallized fluorescent powder.

[0058] Example 5

[0059] An application of a 9-methylacridine eutectic phosphor involves mixing the 9-methylacridine eutectic phosphor prepared in Example 1 with epoxy resin (as an adhesive and encapsulating material) at a mass ratio of 1:5, and stirring thoroughly until a uniformly dispersed phosphor is formed. The prepared phosphor is then precisely coated onto an LED chip substrate with an emission wavelength of 365 nm, ensuring complete and uniform coverage of the chip. The coated LED device is then placed in an oven at 100 °C for 1 h to allow the epoxy resin to fully cure, ultimately yielding a PC-LED lighting device.

[0060] Electrical tests were performed on the PC-LED lighting device after power was applied. Within a drive current range of 10 mA to 100 mA, the device exhibited a strictly linear electroluminescent intensity response. Data fitting yielded a correlation coefficient as high as R0. 2 The linear graph with a coefficient of performance (COP) of 0.998 demonstrates the excellent stability and reliability of this lighting device. Visually, it is evident that as the driving current increases, the brightness of the green light emitted by the device smoothly and significantly increases, without any visible efficiency roll-off or color shift.

[0061] Example 6

[0062] An application of a 9-methylacridine eutectic phosphor involves mixing the 9-methylacridine eutectic phosphor prepared in Example 2 with epoxy resin (as an adhesive and encapsulating material) at a mass ratio of 1:5, and stirring thoroughly until a uniformly dispersed phosphor is formed. The prepared phosphor is precisely coated onto an LED chip substrate with an emission wavelength of 365 nm, ensuring complete and uniform coverage of the chip. The coated LED device is then placed in an oven at 100 °C and heated for 1 hour to allow the epoxy resin to fully cure, forming a stable phosphor conversion layer, ultimately yielding a PC-LED lighting device.

[0063] Electrical tests were performed on the PC-LED lighting device after power was applied. Within a drive current range of 10 mA to 100 mA, the device exhibited a strictly linear electroluminescent intensity response. Data fitting showed a linear correlation coefficient as high as R0. 2 = 0.998, proving that the lighting device has excellent stability and reliability. It can be visually observed that as the driving current increases, the brightness of the green light emitted by the lighting device increases smoothly and significantly, without any visible efficiency roll-off or color shift.

[0064] The performance of the product prepared in Example 1 will be tested below.

[0065] like Figure 2 As shown, Figure 2The simulated curves represent the results of 9-methylacridine eutectic phosphor simulation, while the experimental curves show a high degree of agreement with the diffraction peak data observed through powder X-ray diffraction analysis. Furthermore, the diffraction pattern exhibits clear and distinct diffraction peaks, demonstrating the high crystallinity of the material.

[0066] like Figure 3 As shown, Fourier transform infrared spectroscopy (FT-IR) further illustrates the formation of the target product. The FT-IR spectrum is displayed at 2861 cm⁻¹. -1 There is an absorption peak at 1693 cm⁻¹, which corresponds to the symmetric stretching vibration of the methyl group (-CH₃) in both components; while at 1693 cm⁻¹... -1 The strong absorption peak at this point originates from the stretching vibration of the C=O bond in the undissociated carboxylic acid group (-COOH). Compared with the vibrational frequency of the free -COOH group, this peak shows a slight red shift, approximately 7 cm⁻¹. -1 This phenomenon indicates the presence of hydrogen bonding, but no proton transfer occurred. 1553 cm -1 and 1523 cm -1 The absorption peak at that location originates from the stretching vibrations and / or in-plane bending vibrations of the C=C bond in the aromatic ring, which are related to the carboxylate ion (-COO). - The vibration frequencies of the two are significantly different; the latter typically has a vibration frequency greater than 1600 cm⁻¹. -1 ; and 752 cm -1 The strong absorption peak at this point corresponds to the plane-perpendicular CH bond bending vibration of the intermediate-substituted benzene ring in MeIPA, a phenomenon consistent with its crystal structure characteristics. It is noteworthy that, since N was not observed... + -H bond stretching vibration band (2500-2700 cm) -1 or a wide range of OH bond stretching vibration bands (2500-3300 cm). -1 Therefore, the possibility of proton transfer or ion interaction can be ruled out. This result is consistent with the conclusions obtained from PXRD data analysis, namely that there is indeed a hydrogen bond between the neutral 5-methylisophthalic acid molecule and the 9-methylacridine molecule.

[0067] The fluorescence spectrum characterization of 9-methylacridine phosphor is shown in the figure. Figure 4 The instrument used was an Edinburgh FLS1000 steady-state and transient fluorescence spectrometer. Figure 4 As shown in Figure a, the 9-methylacridinium eutectic phosphor exhibits bright green fluorescence emission (peak position at 530 nm) under excitation by a 365 nm light source. Figure 4 As shown in b, the luminescence decay curve of the 9-methylacridine eutectic phosphor shows a relatively long luminescence lifetime of 39.36 ns.

[0068] The luminescence phenomenon of eutectic phosphor lighting devices under the influence of electric current, such as Figure 5 As shown in Figure a, the emission spectrum changes with increasing driving current; Figure 5 b shows the relationship between the spectral peak intensity and the current under different currents, which, after fitting, exhibits a good linear relationship (R0). 2 = 99.8); Figure 5 c represents the light emission image of the eutectic phosphor lighting device. As the driving current increases, the luminous intensity gradually increases. Figure 5 Image c displays the luminescence intensity at 10 different currents, from left to right in the first row to left to right in the second row: 10 mA, 20 mA, 30 mA, 40 mA, 50 mA, 60 mA, 70 mA, 80 mA, 90 mA, and 100 mA. This demonstrates that the prepared phosphor exhibits excellent luminescence performance in electroluminescence, with high color purity (green, spectrally stable), high efficiency (linear response, no roll-off), and high stability and reliability (extremely high linearity).

[0069] also, Figure 6 Scanning electron microscope images of 9-methylacridine eutectic phosphors show the preparation of the target product.

[0070] Figure 7 X-ray photoelectron spectroscopy (XPS) of 9-methylacridine eutectic phosphor: (a) full X-ray photoelectron spectrum; (b)-(d) high-resolution fine spectra of the corresponding elements, where (b) is the C 1s spectrum, (c) is the O 1s spectrum, and (d) is the N 1s spectrum. XPS spectral analysis shows that the bonding energies in the MeIPA-MeAD molecule are 284.3 eV, 398.4 eV, and 531.9 eV, corresponding to the C 1s, N 1s, and O 1s energy levels. After deconvolution, the C 1s spectrum can be decomposed into four Gaussian peaks at 284.8 eV, 286.5 eV, 288.9 eV, and 291.3 eV, corresponding to C-C bonds, CO bonds, C=O bonds, and a π→π* satellite peak, respectively. The N 1s spectrum shows two component peaks at 398.4 eV and 399.2 eV, corresponding to C=NC bonds and OH···N structures, respectively. These results confirm that the three-dimensional supramolecular structure of MeIPA-MeAD is stabilized by both hydrogen bonding and π-π stacking interactions. These spectroscopic analyses and crystallographic studies together demonstrate that the nonionic eutectic formed by MeIPA-MeAD is actually stabilized by intermolecular hydrogen bonding rather than proton exchange.

[0071] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a 9-methylacridine eutectic phosphor, characterized in that, 5-Methylisophthalic acid and 9-methylacridine were dissolved in an organic solvent in a molar ratio of 1:1-2 and allowed to stand at room temperature to obtain a co-crystallized product. The co-crystallized product was ground to obtain the 9-methylacridine co-crystallized phosphor.

2. The method for preparing a 9-methylacridine eutectic phosphor according to claim 1, characterized in that, The specific process of dissolving 5-methylisophthalic acid and 9-methylacridine in an organic solvent includes: 5-Methylisophthalic acid was dissolved in an organic solvent to obtain a 5-methylisophthalic acid solution, and 9-methylacridine was dissolved in an organic solvent to obtain a 9-methylacridine solution. The 5-methylisophthalic acid solution and the 9-methylacridine solution were then mixed. Alternatively, 5-methylisophthalic acid can be dissolved in an organic solvent to obtain a 5-methylisophthalic acid solution, and 9-methylacridine can be added to the 5-methylisophthalic acid solution.

3. The method for preparing a 9-methylacridine eutectic phosphor according to claim 1, characterized in that, The organic solvent is anhydrous ethanol, methanol, or acetonitrile.

4. The method for preparing a 9-methylacridine eutectic phosphor according to claim 1, characterized in that, The settling time is 10-100 min, and the grinding time is 2-10 min.

5. 9-Methylacridine eutectic phosphor prepared by the preparation method according to any one of claims 1-4.

6. The application of the 9-methylacridine eutectic phosphor as described in claim 5 in the preparation of lighting devices.

7. The application as described in claim 6, characterized in that, 9-Methylacridine eutectic phosphor is mixed evenly with an adhesive to obtain a fluorescent adhesive; the fluorescent adhesive is coated onto an LED chip, and the adhesive is heated to cure, thus obtaining a lighting device, wherein the adhesive is epoxy resin or silicone gel.

8. The application as described in claim 7, characterized in that, The driving current of the lighting device is 20-100 mA.

9. The application as described in claim 7, characterized in that, The LED chip emits light at a wavelength of 365 nanometers.

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