Use of a pyrene derivative in the preparation of a laser-induced fluorescence discoloration self-recovery material

Abstract

The application relates to application of a pyrene derivative in preparation of a laser-induced fluorescence color-changing self-recovery material. The pyrene derivative has a structure represented by the following formula I. The pyrene derivative material of the application has the characteristics of convenient preparation and application, good repeatability, low cost and the like, can be used in the fields of laser writing and anti-fake encryption, and is used for preparing a laser-drawing self-erasing fluorescent film device.

Description

Technical Field

[0001] This invention belongs to the field of stimulus-responsive luminescent materials technology, specifically relating to the application of a pyrene derivative in the preparation of laser-induced fluorescence color change self-recovery materials, particularly in the preparation of laser-written self-erasing fluorescent thin film devices and their application in laser-induced fluorescence color change and spontaneous recovery. Background Technology

[0002] Stimulus-responsive luminescent materials are a class of smart materials that undergo reversible chemical / physical changes in response to external stimuli such as light, heat, gas, electricity, and pH. In recent years, a wealth of photoluminescent materials, especially low-toxicity, low-cost pure organic materials, have been widely developed and applied in fields such as optoelectronics, storage and recording, security printing, and sensors.

[0003] Among the rich system of photochromic materials, photochromic luminescent materials have rapidly developed into a series of different systems due to their excellent reversibility and non-contact driving force (photostimulation). Based on different mechanisms, they can be classified into cis-trans isomerization reactions of azo compounds, pericyclic reactions of spiropyrans and diarylethylene compounds, intramolecular proton transfer of benzylpyridine compounds, intramolecular group transfer of polycyclic quinone compounds, and electron transfer of viologen compounds, etc. However, despite the rich diversity of photochromic luminescent material systems, additional external stimulation (such as ultraviolet / visible light irradiation or heating) is essential to achieve fluorescence color change.

[0004] In contrast, the emission color of thermochromic luminescent materials changes accordingly with temperature fluctuations, making them typically self-reversible thermo-responsive switches. However, triggering this color change often requires a contact heat source or medium to transfer heat, and their patterned applications are quite complex. Furthermore, in some cases, a phase transition in a thermochromic luminescent material can cause an irreversible color change. Therefore, the applications of thermochromic luminescent materials are limited. However, if thermochromic materials could be remotely controlled like photochromic materials, the use of non-contact heat sources would greatly expand their practical applications.

[0005] In organic light-emitting materials, excimers are a special class of luminescent materials, characterized by a large redshift, lack of fine structure, and long lifetime. Due to the striking contrast in emission color between excimers and their monomers, they have become excellent stimulus-responsive fluorescent switching materials. Typically, the emission color conversion of excimer fluorescent switches occurs through stimuli, such as shear forces generated by grinding. However, such destructive external forces can alter the material morphology. Furthermore, excimer emission is generally achieved in concentrated solutions or crystals, and its difficulty in processing severely limits its applications.

[0006] In summary, there are still many problems to be solved in the field of stimulus-responsive luminescent materials. Developing thin-film stimulus-responsive devices with high contrast, spontaneous reversibility and easy processing will become a new and important research direction. Summary of the Invention

[0007] Through in-depth research, the inventors of this invention discovered that a class of pyrene derivatives, through reasonable modification, possess a reversibly changing bistable state. By undergoing a phase transition from crystal to molten (amorphous) solid, the emission color changes from monomer emission to excimer emission. Furthermore, the amorphous excimer emission can spontaneously revert to the original crystalline monomer emission when left to stand. This material can be used as a laser-induced fluorescence color-changing self-recovery material for preparing high-contrast, spontaneously reversible, and easily processed thin-film stimulus-responsive devices, thus completing this invention.

[0008] In a first aspect, the present invention provides an application of a pyrene derivative of Formula I in the preparation of laser-induced fluorescence color change self-recovery materials;

[0009]

[0010] Wherein, R represents substitution at any site on the pyrene ring, selected from substituted or unsubstituted thiazolyl, C6-C12 aryl-thiazolyl, substituted or unsubstituted thiophene, C6-C12 aryl-thiaphene, and the substituent is selected from halogens (such as Cl, Br, I), C1-C6 alkyl or C6-C12 aryl.

[0011] Specifically, the substitution site of the pyrene group can be selected from position 1, position 2, or position 4 on the pyrene ring, that is, the pyrene derivative of formula I can be selected from compounds shown in formula II, formula III, or formula IV:

[0012]

[0013] The definition of R is the same as described above.

[0014] There are no restrictions on the linking sites on the R group; they can be selected from any substitution site on the corresponding group.

[0015] In some embodiments, R is selected from one of the following groups:

[0016]

[0017] Wherein, X is selected from Cl, Br, I, and R1 is selected from C1-C6 alkyl, phenyl, and naphthyl groups.

[0018] In some embodiments, the pyrene derivative of Formula I is selected from the following compounds:

[0019]

[0020]

[0021]

[0022]

[0023] The inventors discovered that the pyrene derivative exhibits a bistable state. In the crystalline phase, its aggregated state characteristics are close to those of monomers (initial stable state), and its luminescence behavior is monomer emission. In the molten solid phase (amorphous state), its aggregated state characteristics are those of excimers (metastable state), and its luminescence behavior is excimer emission. The fluorescence color change behavior of the pyrene derivative material can be induced by laser irradiation (including thermal stimulation). This change originates from a phase transition of the aggregates. Simply put, the initial crystalline aggregates are hydrogen-bonded aggregates, belonging to a thermodynamically stable phase. Under laser stimulation, these aggregates transform into amorphous aggregates dominated by π-π interactions, belonging to a kinetically stable phase, corresponding to a change in fluorescence color from monomer emission to excimer emission. The excimer amorphous aggregates are metastable and gradually revert to the initial stable phase, i.e., the crystalline state with monomer emission, corresponding to a spontaneous and reversible recovery phenomenon.

[0024] Therefore, the pyrene derivatives described in this invention can be used as laser-induced fluorescence self-recovery materials. When the pyrene derivatives of Formula I according to this invention undergo a phase change from crystalline to molten amorphous solid under laser induction, the fluorescence color transitions from monomer emission to excimer emission, and upon resting, it spontaneously recovers from the amorphous state of excimer emission to the crystalline state of monomer emission.

[0025] Laser-induced fluorescence color change self-recovery material refers to a pyrene derivative material that initially emits fluorescence from a crystalline monomer, but becomes amorphous (in a molten solid state) under laser irradiation. At this time, it emits fluorescence as an excimer. After a period of time after irradiation, the pyrene derivative material automatically recovers to its initial crystalline state. At this time, the fluorescence emitted by the excimer disappears, and it reverts to emission from the monomer.

[0026] In a second aspect, the present invention provides the application of a pyrene derivative of Formula I in the fabrication of a laser-written self-erasing fluorescent thin-film device; the laser-written self-erasing fluorescent thin-film device includes at least one layer containing the pyrene derivative described in the first aspect above.

[0027] Thirdly, the present invention provides a laser-written self-erasing fluorescent thin film device, comprising at least one layer containing the pyrene derivative described in the first aspect above.

[0028] There are no particular limitations on the structure of the thin-film device; any existing thin-film device structure can be used, as long as it contains the pyrene derivative according to the present invention. For example, the laser-written thin-film device may consist solely of an undoped thin film containing the pyrene derivative according to the present invention as a phosphorescent material, or the laser-written thin-film device may include a substrate (e.g., a quartz glass substrate) and an undoped thin film containing the pyrene derivative according to the present invention as a phosphorescent material on the substrate, but the present invention is not limited thereto.

[0029] Fourthly, the present invention provides a method for preparing the above-mentioned laser-written self-erasing fluorescent thin film device, comprising the following steps:

[0030] The pyrene derivative described in the first aspect above is placed on a substrate, the substrate is heated to completely melt the pyrene derivative, and then cooled to room temperature (so that the molten liquid of the pyrene derivative solidifies to form an amorphous thin film with excimer emission), thus forming an amorphous thin film device; after standing for 7-14 days, it transforms into a crystalline thin film device with monomer emission.

[0031] In some embodiments, the method for preparing the above-mentioned laser-written self-erasing fluorescent thin film device provided by the present invention includes the following steps:

[0032] The pyrene derivative is placed on a first substrate, the first substrate is heated to completely melt the pyrene derivative, and a second substrate is placed on the first substrate containing the molten pyrene derivative to remove air.

[0033] Cooling to room temperature (to solidify the molten liquid of the pyrene derivative to form an amorphous thin film with excito-association emission) forms an amorphous thin film device;

[0034] After standing for 7-14 days, the amorphous thin-film device transforms into a crystalline thin-film device.

[0035] It should be noted that in this invention, the molten state includes both liquid and solid, both of which are amorphous. The "molten solid" in this invention refers to the amorphous solid formed by melting.

[0036] The fabricated laser-written self-erasing fluorescent thin-film device can be used for subsequent laser-written self-erasing.

[0037] "Laser-written self-erasing" refers to the process where a pattern is written on an initially crystalline thin-film device under a laser. The area swept by the laser becomes amorphous, at which point an excimer is formed and emits fluorescence, thus forming a pattern. After a certain period of time, the amorphous part returns to the initial crystalline state, and the fluorescence emitted by the excimer disappears, thus erasing the pattern.

[0038] Fifthly, the present invention provides a method for laser writing and self-erasing, the method comprising the steps of writing and self-erasing text or patterns using the laser writing and self-erasing fluorescent thin film device of the present invention described above.

[0039] There are no particular restrictions on the laser writing method; any method applicable in this field can be used. For example, direct printing using program-controlled laser printing or mask printing can be used, but it is not limited to these methods.

[0040] In some embodiments, the laser writing and self-erasing method includes the following steps:

[0041] (1) Place the crystalline pyrene derivative of Formula I under a laser writing device for pattern writing; after the pattern is written, the device is irradiated under a light source of 254nm to 365nm, and the pattern part is the fluorescent color emitted by the excimer (the rest is the fluorescent color emitted by the monomer).

[0042] (2) The pattern formed by the fluorescent color emitted by the excitoassociate disappears (it is completely restored to the fluorescent color emitted by the monomer).

[0043] Preferably, in step (1), the laser power is 25-45mW and the drawing speed is 10-60mm / s;

[0044] Preferably, in step (2), the pattern formed by the fluorescent color emitted by the excimer disappears after 2-54 hours.

[0045] It should be understood that the above description is only for better illustrating the use of pyrene derivatives of the present invention as laser-written fluorescent color-changing materials, and is not intended to limit their application as fluorescent color-changing materials.

[0046] Beneficial effects

[0047] The pyrene derivatives provided by this invention are obtained by modifying different sites of pyrene with specific substituents. Compared with traditional fluorescent materials, they possess novel properties and can be used as laser-written fluorescent self-recovering materials. They overcome many drawbacks, and their application advantages are as follows:

[0048] (1) High fluorescence contrast.

[0049] The emission color of these materials transitions between monomer emission and excimer emission. The large redshift emission of the excimer relative to the monomer allows for high-contrast color changes. For example, the pyrene derivative Py-BZT, with pyrene at position 1 and benzothiazole at position 2, can achieve a color change from blue to yellow light.

[0050] (2) Spontaneous reversibility.

[0051] The excimers of this type of material are in an amorphous state, a metastable state, and can spontaneously recover to their initial stable state under normal conditions without any other complex operations. For example, the pyrene derivative Py-BZT corresponds to the transition in emission color from yellow excimer emission to blue monomer emission. Furthermore, this recovery time is related to the laser power intensity, and can be adjusted by regulating the laser power intensity. It can also be used for multiple drawing operations.

[0052] (3) It is easy to operate and apply, and no complicated processing is required.

[0053] When fabricating thin-film devices, this type of material only requires heating and melting the original solid material, pressing it into a film using a substrate, and then spontaneously reverting to a crystalline thin film that emits monomeric light, without any other complex operations.

[0054] When applying thin-film devices, simply select a laser source of appropriate power, input the specific graphic in the software, or draw the graphic yourself using a laser pointer. Thin-film devices can be effectively excited by light sources in the 254nm–365nm range, which are commonly found in daily life, making on-site testing convenient. For example, the pyrene derivative Py-BZT emits blue fluorescence as a monomer, while its excimer emits yellow fluorescence. This color difference is easily observable, allowing for clear differentiation of drawn patterns or text, providing a unique advantage in encryption and anti-counterfeiting.

[0055] (4) Compared with traditional smart response color-changing materials, these materials are all pure organic simple small molecules, the raw materials are cheap and readily available, the preparation method is simple and easy to modify, and they are more environmentally friendly. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the structure of the laser-written fluorescent color-changing thin film device prepared in Example 5 of the present invention.

[0057] Illustration: 1- Quartz glass substrate; 2- Fluorescent color-changing material thin film.

[0058] Figure 2 This is the differential scanning calorimetry curve of Py-BZT material.

[0059] Figure 3 These are the fluorescence emission spectra of Py-BZT material crystals and molten solids.

[0060] Figure 4 These are X-ray diffraction patterns of Py-BZT material crystals and molten solids.

[0061] Figure 5 This is the differential scanning calorimetry curve of Py-BZTp material.

[0062] Figure 6These are the fluorescence emission spectra of Py-BZTp material crystals and molten solids.

[0063] Figure 7 These are X-ray diffraction patterns of Py-BZTp material crystals and molten solids.

[0064] Figure 8 This is the fluorescence emission spectrum of a thin-film device fabricated from Py-BZT material.

[0065] Figure 9 These are the fluorescence lifetime curves of thin-film devices fabricated from Py-BZT materials.

[0066] Figure 10 These are photographs depicting the disappearance of snowflake patterns drawn on Py-BZT crystalline thin-film devices using lasers of different power.

[0067] Figure 11 This is a schematic diagram illustrating the information storage and encryption application using Py-BZT crystalline thin-film devices.

[0068] Figure 12 This is the differential scanning calorimetry curve of Py-BZC material.

[0069] Figure 13 These are the fluorescence emission spectra of Py-BZC material crystals and molten solids.

[0070] Figure 14 These are X-ray diffraction patterns of Py-BZC material crystals and molten solids.

[0071] Figure 15 This is the differential scanning calorimetry curve of Py-BZO material.

[0072] Figure 16 These are the fluorescence emission spectra of Py-BZO material crystals and molten solids.

[0073] Figure 17 These are X-ray diffraction patterns of Py-BZO material crystals and molten solids. Detailed Implementation

[0074] The present invention will be further described in detail below through specific embodiments. The following examples are only for explaining the purpose of the invention and are not intended to limit the scope of the invention. Where the implementation conditions are not specified in the embodiments, the implementation conditions adopted are those found in literature available in the art. Reagents or instruments whose manufacturers are not specified are all generally available commercial products.

[0075] Experimental drugs and reagents

[0076] All chemical reagents used in the experiment were produced by Beijing Chemical Reagent Company, and all chemical reagents involved in the synthesis of materials were purchased and used directly by Anaiji Chemical Co., Ltd. and Bailingwei Technology Co., Ltd.

[0077] Testing instruments

[0078] MRI 1 H and 13 C-wave spectra were measured using a Bruker AVANCE 500MHz or 600MHz nuclear magnetic resonance spectrometer.

[0079] Mass spectrometry tests were performed using an ITQ1100 ion trap gas chromatograph-mass spectrometer.

[0080] Differential scanning calorimetry (DSC) curves were obtained using a differential scanning calorimeter manufactured by TA Instruments, Inc. under nitrogen protection. The scanning range was 25-280℃, and the heating / cooling rate was 10℃ / min.

[0081] Fluorescence emission spectra and fluorescence lifetimes were measured using a FLS980 steady-state and transient fluorescence spectrometer in Edinburgh, UK, at room temperature. The excitation wavelength for emission spectroscopy was 365 nm, and the excitation wavelength for fluorescence lifetime was 375 nm.

[0082] X-ray diffraction patterns were obtained using a SmartLab(3) intelligent powder X-ray diffractometer manufactured by Rigaku Corporation of Japan at room temperature, with a scanning angle of 5-50° and a scanning speed of 5° / min.

[0083] Preparation Example 1: Preparation of Py-BZT Materials

[0084]

[0085] 1-Pyrenecarboxaldehyde (465 mg, 2.0 mmol) and 2-aminobenzylthiol (257 μL, 2.4 mmol) were added to a 100 mL single-necked round-bottom flask, followed by the addition of 15 mL of DMSO to dissolve them completely. The mixture was heated under reflux at 170 °C for 12 h under a nitrogen atmosphere. After the reaction was completed, the mixture was cooled to room temperature, and 50 mL of deionized water was added. The mixture was extracted with dichloromethane (3 × 150 mL), and the organic phase was collected and dried over anhydrous sodium sulfate. The mixture was filtered, and the solvent was removed by vacuum distillation. The resulting crude solid product was purified by silica gel column chromatography (eluting solvents: petroleum ether and dichloromethane) to obtain a pale yellow powder (220 mg), with a yield of 33%.

[0086] Relevant characteristics:

[0087] 1H NMR (500MHz, DMSO-d6, 25℃, TMS): δ = 9.38 (d, J = 9.4Hz, 1H), 8.57 (d, J = 8.0Hz, 1H), 8.49 (d, J = 8.0Hz, 1H), 8.43 (dd, J = 13.3, 5.9H z,3H),8.37(d,J=8.9Hz,1H),8.30(dd,J=18.3,8.7Hz,3H),8.19(t,J=7.6Hz,1H),7.66(t,J=8.0Hz,1H),7.58(t,J=7.8Hz,1H).

[0088] 13 C NMR (126MHz, CDCl3, 25℃, TMS): δ=168.20(C), 154.44(C), 135.92(C), 132.75( C),131.32(C),130.84(C),129.28(CH),129.08(C),128.95(CH),128.50(CH) ,127.47(C),127.19(CH),126.34(CH),125.99(CH),125.75(CH),125.27(CH) ,125.13(C),125.05(CH),124.65(CH),124.48(C),123.64(CH),121.42(CH).

[0089] GC / MS,EI(mass m / z):334.07[M+].

[0090] Preparation Example 2: Preparation of Py-BZTp Material

[0091]

[0092] 1-Bromopyrene (1405 mg, 5 mmol), benzo[b]thiophene-2-ylboronic acid (534 mg, 3 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (140 mg, 0.09 mmol), and K2CO3 (2.2 g, 15.6 mmol) were added to a 100 mL single-necked round-bottom flask, followed by 8 mL of deionized water and 12 mL of toluene, and degassed to remove oxygen. The mixture was stirred and refluxed at 95 °C under a nitrogen atmosphere for 48 h. After the reaction was complete, the mixture was cooled to room temperature, and 50 mL of deionized water was added. The mixture was extracted with dichloromethane (3 × 150 mL), the organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation. The resulting crude solid product was purified by silica gel column chromatography (eluting solvent: petroleum ether and dichloromethane) to obtain a white powder (761 mg), with a yield of 76%.

[0093] Relevant characteristics:

[0094] 1 H NMR (600MHz, DMSO-d6, 25℃, TMS): δ = 8.55 (d, J = 9.2Hz, 1H), 8.44–8.35 (m, 3H), 8.32–8.24 (m, 4H), 8 .15(t,J=7.6Hz,1H),8.11(d,J=8.2Hz,1H),8.02(d,J=7.2Hz,1H),7.83(s,1H),7.54–7.44(m,2H).

[0095] 13 C NMR (151MHz, CDCl3, 25℃, TMS): δ=142.83,140.73,140.40,131.47,131.39,130.96,129.68,129.32,128.48,128.17, 128.09,127.36,126.25,125.53,125.26,125.01,124.95,124.76,124.63,124.60,124.57,124.34,123.72,122.17.

[0096] GC / MS, EI (mass m / z): 333.93.

[0097] Test Example 3: Characterization of Py-BZT Materials

[0098] Differential scanning calorimetry was performed on the Py-BZT material prepared in Preparation Example 1.

[0099] Figure 2 This is the differential scanning calorimetry (DSC) curve of Py-BZT material. During the first cycle of heating, Py-BZT exhibits an endothermic peak at 136℃, representing its melting point of 136℃. During the cooling process, the curve shows no significant heat change, indicating that the molten Py-BZT remains amorphous from melting to returning to room temperature. During the second cycle of heating, two consecutive exothermic peaks appear at 90℃ and 99℃, and an endothermic peak representing the melting point reappears at 136℃, suggesting that the exothermic peaks may correspond to the crystallization and phase transition processes, respectively.

[0100] 10 mg of Py-BZT material was dissolved in 1 mL of CDCl3 solvent to prepare a concentrated solution. The solution was allowed to stand and culture to form crystals. After about three days, a yellow blocky solid precipitated, which was the Py-BZT material crystal. 2 mg of Py-BZT material was placed on a clean quartz plate, heated to melt, and slowly cooled to room temperature to form a molten Py-BZT material solid. The obtained crystals and molten solid were analyzed by fluorescence emission spectroscopy and X-ray diffraction pattern.

[0101] Figure 3 This is the fluorescence emission spectrum of Py-BZT material crystals and molten solids. For example... Figure 3 As shown, the fluorescence emission peak of Py-BZT crystal is at 468 nm, with a shoulder peak at 495 nm, which is attributed to the emission of the monomer; the fluorescence emission peak of Py-BZT molten solid is at 537 nm, which is attributed to the emission of the excitoassociate.

[0102] Figure 4 The X-ray diffraction patterns of Py-BZT material crystal and molten solid are shown. The crystal exhibits obvious sharp diffraction peaks, indicating its crystalline state. The X-ray diffraction curve of the molten solid shows a broad band with no obvious diffraction peaks, indicating that it is in an amorphous state.

[0103] Test Example 4: Characterization of Py-BZTp Materials

[0104] Differential scanning calorimetry was performed on the Py-BZTp material prepared in Preparation Example 2.

[0105] Figure 5 This is the differential scanning calorimetry (DSC) curve of Py-BZTp material. During the first cycle of heating, Py-BZTp exhibits an endothermic peak at 181℃, representing its melting point of 181℃. During the cooling process, the curve shows no significant heat change, indicating that the molten Py-BZTp remains amorphous from melting to returning to room temperature. During the second cycle of heating, exothermic and endothermic peaks appear at 94℃ and 146℃, respectively, and an endothermic peak representing the melting point reappears at 181℃, suggesting that the exothermic and endothermic peaks may correspond to the crystallization and phase transition processes, respectively.

[0106] 2 mg of Py-BZTp material was dissolved in 1 mL of tetrahydrofuran / methanol mixed solvent and allowed to stand for crystal growth. After about three days, a white flaky solid precipitated, which was the Py-BZTp material crystal. 2 mg of Py-BZTp material was placed on a clean quartz plate, heated to melt, and slowly cooled to room temperature to form a molten solid of Py-BZTp material. The obtained crystal and molten solid were analyzed by fluorescence emission spectroscopy and X-ray diffraction pattern.

[0107] Figure 6 These are the fluorescence emission spectra of Py-BZTp material crystals and molten solids. For example... Figure 6 As shown, the fluorescence emission peak of Py-BZTp crystal is at 436 nm, with a shoulder peak at 459 nm, which is attributed to the emission of the monomer; the fluorescence emission peak of Py-BZTp molten solid is at 498 nm, which is attributed to the emission of the excitopolymer.

[0108] Figure 7The X-ray diffraction patterns of Py-BZTp material crystals and molten solids are shown. The crystals exhibit obvious sharp diffraction peaks, indicating their crystalline nature. The X-ray diffraction curves of the molten solids show a broad band with no obvious diffraction peaks, indicating that they are in an amorphous state.

[0109] The crystal and molten solid evolution trends of Py-BZTp materials are consistent with those of Py-BZT materials, demonstrating that they possess the same properties and application potential. However, the fluorescence color of Py-BZT materials varies between blue and yellow, while that of Py-BZTp materials varies between blue and green. Therefore, subsequent application examples will use Py-BZT materials, which exhibit a more pronounced fluorescence color contrast, as examples.

[0110] Preparation Example 5: Fabrication of Laser-Drawn Fluorescent Color-Changing Thin Film Devices

[0111] Taking the Py-BZT material prepared in Example 1 as an example, a laser-written fluorescent color-changing thin film device was fabricated, and its schematic structure is shown below. Figure 1 As shown, it includes two quartz glass substrates 1, one above the other, and an undoped thin film containing Py-BZT phosphorescent material (i.e., phosphorescent material thin film 2) sandwiched between the substrates.

[0112] The specific steps include: placing two clean quartz glass substrates on a heating stage, labeling them quartz substrate A and quartz substrate B respectively; placing 2 mg of Py-BZT material on quartz substrate A; starting the heating stage and setting the heating temperature to 140°C; and after the Py-BZT material on quartz substrate A has completely melted, slowly covering quartz substrate B with the molten Py-BZT liquid on quartz substrate A; fixing quartz substrate A and slowly moving quartz substrate B until all air is expelled; and slowly cooling to room temperature to allow the molten Py-BZT liquid to solidify and form an amorphous thin film device with yellow excimer emission. After standing for 7-14 days, the amorphous thin film device with yellow excimer emission transforms into a crystalline thin film device with blue monomer emission, which can be used for subsequent laser drawing.

[0113] Figure 8 This is the fluorescence emission spectrum of a thin-film device fabricated from Py-BZT material. For example... Figure 8 As shown, the fluorescence emission peak of the crystalline film device is at 468 nm, which is attributed to the emission of the monomer; the fluorescence emission peak of the Py-BZT molten solid is at 537 nm, which is attributed to the emission of the excitopolymer. The fluorescence emission spectra of the two devices are in perfect agreement with the emission spectra of the Py-BZT crystal and the molten solid, which further proves that the thin film devices correspond to the crystalline and amorphous states, respectively.

[0114] Figure 9 These are the fluorescence lifetime curves of thin-film devices fabricated from Py-BZT materials. For example... Figure 9As shown, the fluorescence lifetime of crystalline thin-film devices is shorter than that of amorphous thin-film devices, proving that crystalline thin-film devices emit fluorescence as monomers, while amorphous thin-film devices emit fluorescence as excito-associations.

[0115] Application Example 6:

[0116] The blue monomer-emitting crystalline thin-film device prepared in Example 5 was placed under a laser engraving device (a DIAOTU K6 Pro laser engraving machine was used in this example). The pattern to be engraved was input into the accompanying software, and the laser power (25-45mW) and engraving speed (10-60mm / s) were set. After adjusting the position of the thin-film device and the laser, the software automatically controlled the pattern drawing. After the pattern was completed, the thin-film device displayed the specific pattern under a 365nm ultraviolet lamp. The areas scanned by the laser showed yellow fluorescence, while the blank areas showed blue fluorescence. Notably, the yellow fluorescent areas disappeared and reverted to blue fluorescence after 2-54 hours, and the disappearance time was related to the laser power and engraving speed used for drawing, as detailed in the documentation. Figure 10 More notably, this thin-film device can be reused multiple times.

[0117] Figure 10 This describes the disappearance process of a "snowflake" pattern drawn on a crystalline thin-film device using lasers of varying power. For example... Figure 10 As shown, as the laser power increases, the duration of the "snowflake" pattern increases accordingly, and the pattern can completely disappear, restoring the device to its original state.

[0118] Figure 11 This refers to information storage and encryption applications utilizing crystalline thin-film devices. For example... Figure 11 As shown, "bamboo" and "panda" were drawn on a crystalline thin-film device using lasers of different powers. After standing for 2-7 hours, the bamboo drawn with the low-power laser disappeared spontaneously first, followed by the "panda" drawn with the high-power laser, and the device returned to its original blank state. Therefore, information encryption can be achieved.

[0119] To compare with other modified pyrene derivatives, the following experiments were conducted:

[0120] Preparation of Comparative Example 7: Preparation of Py-BZC Material

[0121]

[0122] 1-Pyreneboronic acid (738 mg, 3 mmol), 2-bromoindene (975 mg, 5 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (140 mg, 0.09 mmol), and K2CO3 (2.2 g, 15.6 mmol) were added to a 100 mL single-necked round-bottom flask, followed by 8 mL of deionized water and 12 mL of toluene, and the mixture was degassed and deoxygenated. The mixture was stirred and refluxed at 95 °C under a nitrogen atmosphere for 48 h. After the reaction was complete, the mixture was cooled to room temperature, and 50 mL of deionized water was added. The mixture was extracted with dichloromethane (3 × 150 mL), the organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation. The resulting crude solid product was purified by silica gel column chromatography (eluting solvent: petroleum ether and dichloromethane) to obtain a yellow powder (787 mg), with a yield of 83%.

[0123] Relevant characteristics:

[0124] 1 H NMR (500MHz, DMSO-d6, 25℃, TMS): δ=8.62(d,J=9.3Hz,1H),8.37–8.30(m,3H),8.24(d,J=18.2Hz,4H),8.11 (t,J=7.6Hz,1H),7.60(m,J=11.3,7.4Hz,2H),7.37(d,J=10.6Hz,2H),7.28(t,J=7.4Hz,1H),4.18(s,2H).

[0125] 13 C NMR (151MHz, CDCl3, 25℃, TMS): δ=146.39,145.53,143.62,133.21,132.41,131.60,131.08,130.53,128.75 ,127.62,127.56,127.44,126.83,126.51,126.11,125.25,125.05,124.92,124.66,123.78,121.24,43.18.

[0126] GC / MS, EI (mass m / z): 315.97.

[0127] Comparative Example 8: Preparation of Py-BZO Materials

[0128]

[0129] 1-Pyreneboric acid (738 mg, 3 mmol), 2-chlorobenzoxazole (760 mg, 5 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4) (140 mg, 0.09 mmol), and K2CO3 (2.2 g, 15.6 mmol) were added to a 100 mL single-necked round-bottom flask, followed by 8 mL of deionized water and 12 mL of toluene, and degassed to remove oxygen. The mixture was stirred and refluxed at 95 °C under a nitrogen atmosphere for 48 h. After the reaction was complete, the mixture was cooled to room temperature, and 50 mL of deionized water was added. The mixture was extracted with dichloromethane (3 × 150 mL), the organic phase was collected, dried over anhydrous sodium sulfate, filtered, and the solvent was removed by vacuum distillation. The resulting crude solid product was purified by silica gel column chromatography (eluting solvent: petroleum ether and dichloromethane) to obtain a yellow powder (766 mg), with a yield of 80%.

[0130] Relevant characteristics:

[0131] 1 H NMR (500MHz, DMSO-d6, 25℃, TMS): δ = 9.79 (d, J = 9.4Hz, 1H), 8.93 (d, J = 8.2Hz, 1H), 8.51 (m, J = 8.8, 3.4Hz, 2H), 8.47 (d, J = 7.7Hz, 2 H),8.40(d,J=8.9Hz,1H),8.33(d,J=8.9Hz,1H),8.21(t,J=7.6Hz,1H),8.05–7.98(m,1H),7.95–7.90(m,1H),7.58–7.46(m,2H).

[0132] 13 C NMR (126MHz, CDCl3, 25℃, TMS): δ=163.49,150.41,142.36,133.58,131.20,130.64,129.98,129.62,129 .41,127.68,127.25,126.40,126.28,126.15,125.30,125.07,124.67,124.35,120.21,120.07,110.58.

[0133] GC / MS, EI (mass m / z): 319.46.

[0134] Test Example 9: Characterization of Py-BZC Materials

[0135] Differential scanning calorimetry was performed on the Py-BZC material prepared in Comparative Example 7.

[0136] Figure 12This is the differential scanning calorimetry (DSC) curve of Py-BZC material. During the heating process of the first cycle, Py-BZC exhibits an endothermic peak at 139℃, indicating its melting point is 139℃. During the cooling process, the curve shows an exothermic peak at 132℃, corresponding to the exothermic peak of molten liquid solidification. In the second cycle, there are no obvious endothermic or exothermic peaks, indicating that it remains in an amorphous state after melting, and heating is insufficient to promote its crystallization.

[0137] 2 mg of Py-BZC material was dissolved in 1 mL of tetrahydrofuran / methanol mixed solvent and allowed to stand for crystal growth. After about three days, a yellow flaky solid precipitated, which was the Py-BZC material crystal. 2 mg of Py-BZC material was placed on a clean quartz plate, heated to melt, and slowly cooled to room temperature to form a Py-BZC material molten solid. The obtained crystals and molten solid were analyzed by fluorescence emission spectroscopy and X-ray diffraction pattern.

[0138] Figure 13 This is the fluorescence emission spectrum of Py-BZC material crystals and molten solids. For example... Figure 13 As shown, the fluorescence emission peak of Py-BZC crystal is at 467 nm, with a shoulder peak at 486 nm, which is attributed to the emission of the monomer; the fluorescence emission peak of Py-BZC molten solid is at 515 nm, which is attributed to the emission of the excitoassociate.

[0139] Figure 14 These are X-ray diffraction patterns of Py-BZC material crystals and molten solids. The crystals exhibit obvious sharp diffraction peaks, indicating their crystalline nature. The X-ray diffraction curves of the molten solids show a broad band with no obvious diffraction peaks, indicating that they are in an amorphous state.

[0140] Although the Py-BZC material prepared in Comparative Example 7 can achieve fluorescence color changes from crystalline to molten solid amorphous state, its differential scanning calorimetry curve shows that it does not have self-recovery capability. Therefore, Py-BZC material is not suitable for preparing fluorescent thin film devices for laser writing self-erasing.

[0141] Test Example 10: Characterization of Py-BZO Materials

[0142] Differential scanning calorimetry was performed on the Py-BZO material prepared in Comparative Example 8.

[0143] Figure 15 This is the differential scanning calorimetry (DSC) curve of Py-BZO material. During the heating process of the first cycle, Py-BZO exhibits an endothermic peak at 199℃, indicating its melting point of 199℃. During the cooling process, the curve shows an exothermic peak at 138℃, corresponding to the exothermic peak of crystallization. The second cycle is exactly the same as the first cycle, indicating that Py-BZO material has strong crystallinity and is difficult to form a stable molten solid phase.

[0144] 2 mg of Py-BZO material was dissolved in 1 mL of tetrahydrofuran / methanol mixed solvent and allowed to stand for crystal growth. After about three days, yellow needle-like solids precipitated, which were Py-BZO material crystals. 2 mg of Py-BZO material was placed on a clean quartz plate, heated to melt, and slowly cooled to room temperature to form a Py-BZO material molten solid. The obtained crystals and molten solids were analyzed by fluorescence emission spectroscopy and X-ray diffraction pattern analysis.

[0145] Figure 16 This is the fluorescence emission spectrum of Py-BZO material crystals and molten solids. For example... Figure 16 As shown, the fluorescence emission peak of Py-BZO crystal is at 468 nm, with a shoulder peak at 493 nm, which is attributed to the emission of the monomer. The fluorescence emission peak of Py-BZO molten solid is consistent with that of its crystal, indicating that Py-BZO material has strong crystallinity and is difficult to form a stable molten solid phase.

[0146] Figure 17 The X-ray diffraction patterns of Py-BZO material crystals and molten solids are shown. The crystals exhibit obvious sharp diffraction peaks, indicating their crystalline nature. The X-ray diffraction curves of the molten solids show a broad band with no obvious diffraction peaks, indicating that they are in an amorphous state.

[0147] The Py-BZO material prepared in Comparative Example 8 could not achieve a fluorescence color change from crystalline to molten solid amorphous state. Therefore, Py-BZO material is not suitable for preparing fluorescent thin film devices for laser writing self-erasing.

Claims

1. The application of a pyrene derivative in the preparation of laser-induced fluorescence color-changing self-restoring materials, wherein, The pyrene derivative is selected from compounds of formula II, III or IV: II III IV Where R is selected from .

2. The application according to claim 1, wherein, The pyrene derivatives are selected from the following compounds: 。 3. The use of the pyrene derivative of claim 1 or 2 in the preparation of a laser-written self-erasing fluorescent thin film device, wherein the laser-written self-erasing fluorescent thin film device comprises at least one layer containing the pyrene derivative.

4. A laser-written self-erasing fluorescent thin-film device comprising at least one layer containing a pyrene derivative as described in claim 1 or 2.

5. A method for fabricating a laser-written self-erasing fluorescent thin-film device, comprising: The pyrene derivative of claim 1 or 2 is placed on a substrate, the substrate is heated to completely melt the pyrene derivative, and then cooled to room temperature to form an amorphous thin film device with excimer emission; after standing for 7-14 days, it transforms into a crystalline thin film device with monomer emission.

6. The method of claim 5, further comprising: The pyrene derivative is placed on a first substrate, the first substrate is heated to completely melt the pyrene derivative, and a second substrate is placed on the first substrate containing the molten pyrene derivative to remove air. Cooling to room temperature forms an amorphous thin-film device that emits excito-pair composite emission. After standing for 7-14 days, the amorphous thin-film device transforms into a crystalline thin-film device.

7. A method for laser writing and self-erasing, the method using the laser writing and self-erasing fluorescent thin film device of claim 4, comprising the following steps: (1) Place the crystalline pyrene derivative laser-written self-erasing fluorescent thin film device under the laser writing equipment and perform pattern writing; after the pattern writing is completed, the device is irradiated under a 254 nm~365 nm light source, and the pattern part is the fluorescent color emitted by the excimer; (2) The pattern formed by the fluorescent color emitted by the excito-association compound disappears.

8. The method according to claim 7, wherein, In step (1), the laser power is 25-45 mW and the drawing rate is 10-60 mm / s; In step (2), after 2-54 h, the pattern formed by the fluorescent color emitted by the excimer disappears.

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