Epsilon-polylysine-based organic room-temperature phosphorescent material, preparation method and application thereof

Abstract

The application discloses an epsilon-polylysine-based organic room-temperature phosphorescent material and a preparation method and application thereof, and is prepared by the following steps: dissolving a phosphor in anhydrous ethanol to prepare solution 1; dissolving epsilon-polylysine in deionized water to prepare solution 2; mixing the solution 1 and the solution 2, and reacting under the protection of inert gas or nitrogen, concentrating, and drying to obtain the epsilon-polylysine-based organic room-temperature phosphorescent material. The phosphorescent material has high quantum yield and long lifetime room-temperature phosphorescent properties, and can be used in the fields of anti-counterfeiting materials, information encryption, data storage, medical imaging and the like. The phosphorescent material has the advantages of wide wavelength range, adjustable color, high quantum yield, super-long lifetime, simple preparation, cheap raw materials, good stability and the like, and can realize the characteristics of multiple stimulus responses. The afterglow emission can be maintained for more than 15s at room temperature. The phosphorescent lifetime of the epsilon-polylysine-based room-temperature phosphorescent material is up to 2505ms through phosphorescent lifetime decay curve fitting.

Description

Technical Field

[0001] This invention relates to the technical field of pure organic luminescent materials and anti-counterfeiting encryption materials, and particularly to an ε-polylysine-based organic room temperature phosphorescent material, its preparation method, and its application. Background Technology

[0002] In recent years, afterglow materials have attracted much attention due to their unique properties. A large number of inorganic afterglow materials have been developed, but the high cost of rare earth materials and the complex synthesis processes used in their preparation limit their further development. Compared with inorganic phosphorescent materials, organic room-temperature phosphorescent materials have advantages such as low cost, abundant sources, ease of synthesis, good biocompatibility, and easy modification of functional groups. They have promising application prospects in many high-tech fields such as bioimaging, optical recording, information storage, encryption, and anti-counterfeiting systems. Currently, many strategies have been developed to achieve room-temperature phosphorescence (RTP) in organic materials, ranging from π-π stacking interactions to host-guest interactions, crystallization and co-crystallization, carbon dots (CDs), heavy atom effects, and polymer doping. As a rigid matrix, suppressing nonradiative decay processes and further promoting room-temperature phosphorescence emission are receiving increasing attention. In general, promoting organic RTP follows the principles of promoting intersystem crossing (ISC) and suppressing nonradiative transitions to mitigate the quenching of triplet excitons.

[0003] However, most reported phosphorescent materials have a narrow emission wavelength range and limited tunable colors, which greatly restricts their applications. Furthermore, materials capable of simultaneously achieving multiple stimulus responses are uncommon, and their phosphorescence lifetimes are short, only a few hundred milliseconds, with poor stability. Studies on long-lifetime phosphorescence emission with a 15-second afterglow time under environmental conditions are even rarer. This significantly limits their potential applications.

[0004] Therefore, it is necessary to develop a polymer-based RTP material with adjustable color, long lifespan, and multiple stimulus responses to address the shortcomings of existing technologies and solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide an ε-polylysine-based organic room temperature phosphorescent material that achieves tunable phosphorescence color, wide wavelength coverage, long lifetime and high quantum yield, and multiple stimulus responses.

[0006] The second objective of this invention is to provide a method for preparing ε-polylysine-based organic room-temperature phosphorescent materials that is simple to prepare, uses inexpensive raw materials, and has good product stability.

[0007] The third objective of this invention is to provide an application of ε-polylysine-based organic room-temperature phosphorescent material as an anti-counterfeiting and encryption material.

[0008] The fourth objective of this invention is to provide an ε-polylysine-based organic room-temperature phosphorescent material for use as a room-temperature phosphorescent material.

[0009] The technical solution of this invention is summarized as follows:

[0010] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0011] Solution 1 is prepared by dissolving phosphor in anhydrous ethanol; Solution 2 is prepared by dissolving ε-polylysine with an average molecular weight of 3800-4200 in deionized water; Solution 1 and Solution 2 are mixed at a mass ratio of phosphor to ε-polylysine of 1:100-200, and stirred and heated to 45-60°C under inert gas or nitrogen protection for 3-5 hours. After rotary evaporation and concentration, the mixture is dried to obtain ε-polylysine-based organic room temperature phosphorescent material.

[0012] Preferably, the phosphor is 9,10-diaminophenanthrene, 2,3-naphthalenedicarboxylic acid, 6-amino-2-naphthalic acid, 5-amino-2-naphthalenesulfonic acid, or 1-aminopyrene.

[0013] Preferably, the inert gas is argon or helium.

[0014] Preferably, the drying is carried out in a vacuum oven at a temperature of 60–80°C.

[0015] The above preparation method produces ε-polylysine-based organic room-temperature phosphorescent materials.

[0016] Application of ε-polylysine-based organic room temperature phosphorescent materials as anti-counterfeiting and encryption materials.

[0017] Application of ε-polylysine-based organic room temperature phosphorescent materials as room temperature phosphorescent materials.

[0018] Advantages of this invention:

[0019] The ε-polylysine-based organic room-temperature phosphorescent material of this invention can serve as a long-lifetime room-temperature phosphorescent material, possessing high quantum yield and long-lifetime room-temperature phosphorescence properties. It can be used in fields such as anti-counterfeiting materials, information encryption, data storage, and medical imaging. It also has advantages such as wide wavelength range and tunable color, high quantum yield, ultra-long lifetime, simple preparation, inexpensive raw materials, and good stability. At the same time, it can achieve multiple stimulus responses. The afterglow emission can be maintained for more than 15 seconds at room temperature. The phosphorescence lifetime of the ε-polylysine-based room-temperature phosphorescent material obtained by fitting the phosphorescence lifetime decay curve is as long as 2505 ms. Attached Figure Description

[0020] Figure 1 The phosphorescence spectrum of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 1;

[0021] Figure 2 The phosphorescence lifetime decay curve of the ε-polylysine-based organic room temperature phosphorescent material obtained in Example 1 is shown.

[0022] Figure 3 These are afterglow images of the ε-polylysine-based organic room-temperature phosphorescent materials obtained in Examples 1-5 at different times after being excited by ultraviolet light and the light source was removed;

[0023] Figure 4 These are afterglow photographs of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 1 after irradiation at different excitation wavelengths and removal of the light source;

[0024] Figure 5 The phosphorescence spectra of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 1 at different excitation wavelengths are shown.

[0025] Figure 6 The phosphorescence spectrum of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 2;

[0026] Figure 7 The phosphorescence lifetime decay curve of the ε-polylysine-based organic room temperature phosphorescent material obtained in Example 2 is shown.

[0027] Figure 8 The phosphorescence spectrum of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 3;

[0028] Figure 9 The phosphorescence lifetime decay curve of the ε-polylysine-based organic room temperature phosphorescent material obtained in Example 3 is shown.

[0029] Figure 10 The phosphorescence spectrum of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 4;

[0030] Figure 11 The phosphorescence lifetime decay curve of the ε-polylysine-based organic room temperature phosphorescent material obtained in Example 4 is shown.

[0031] Figure 12 These are phosphorescence images of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 4 at different delay times;

[0032] Figure 13 The phosphorescence spectra of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 4 at different delay times are shown.

[0033] Figure 14The phosphorescence spectrum of the ε-polylysine-based organic room-temperature phosphorescent material obtained in Example 5;

[0034] Figure 15 The phosphorescence lifetime decay curve of the ε-polylysine-based organic room temperature phosphorescent material obtained in Example 5 is shown.

[0035] Figure 16 These are photographs of the double-encryption model prepared from the ε-polylysine-based organic room-temperature phosphorescent materials obtained in Examples 1-5. Detailed Implementation

[0036] To better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the embodiments and accompanying drawings.

[0037] It should be understood that the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0040] Solution 1 was prepared by dissolving 1 mg of phosphor (9,10-diaminophenanthrene, abbreviated as Daphe) in 2 ml of anhydrous ethanol; Solution 2 was prepared by dissolving 100 mg of ε-polylysine (ε-PL) with an average molecular weight of 3800-4200 in 5 ml of deionized water; Solution 1 and Solution 2 were mixed at a mass ratio of phosphor to ε-polylysine of 1:100, stirred and heated to 50°C under nitrogen protection, and reacted for 4 hours. After rotary evaporation and concentration, the mixture was dried in a vacuum oven at 60°C to obtain ε-polylysine-based organic room temperature phosphorescent material, named Daphe@ε-PL.

[0041] Figure 1 The phosphorescence spectrum of ε-polylysine-based organic room-temperature phosphorescent material (Daphe@ε-PL) is shown; its quantum yield was measured to be 4.45%.

[0042] Figure 2 The phosphorescence lifetime decay curves of ε-polylysine-based organic room temperature phosphorescent material (Daphe@ε-PL) at 471 nm, 505 nm and 530 nm are shown. By fitting, the phosphorescence lifetimes are found to be 2505 ms at 471 nm, 1850 ms at 505 nm and 1175 ms at 530 nm.

[0043] Figure 3Images of the afterglow of the ε-polylysine-based organic room-temperature phosphorescent material (Daphe@ε-PL) obtained in Example 1 at different times after excitation by a 365nm UV lamp and removal of the excitation source show that the ε-polylysine-based organic room-temperature phosphorescent material (Daphe@ε-PL) has an ultra-long room-temperature phosphorescence property, with the blue afterglow lasting up to 15 seconds at room temperature. Furthermore, this material exhibits excitation dependence.

[0044] Figure 4 Afterglow photographs of ε-polylysine-based organic room-temperature phosphorescent material (Daphe@ε-PL) after irradiation at different excitation wavelengths and removal of the light source.

[0045] Figure 5 The phosphorescence spectra of ε-polylysine-based organic room-temperature phosphorescent material (Daphe@ε-PL) at different excitation wavelengths are shown. As the excitation wavelength increases, the corresponding emission wavelength gradually redshifts.

[0046] Example 2

[0047] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0048] Solution 1 was prepared by dissolving 5 mg of phosphor (2,3-naphthalenedicarboxylic acid, abbreviated as NDA) in 10 ml of anhydrous ethanol; Solution 2 was prepared by dissolving 500 mg of ε-polylysine with an average molecular weight of 3800-4200 in 10 ml of deionized water; Solution 1 and Solution 2 were mixed at a mass ratio of phosphor to ε-polylysine of 1:100, stirred and heated to 45°C under argon protection, and reacted for 5 hours. After rotary evaporation and concentration, the mixture was dried in a vacuum oven at 80°C to obtain ε-polylysine-based organic room temperature phosphorescent material, named NDA@ε-PL.

[0049] Figure 6 The phosphorescence spectrum of ε-polylysine-based organic room temperature phosphorescent material (NDA@ε-PL) was obtained, and its quantum yield was measured to be 12.82%.

[0050] Figure 7 The phosphorescence lifetime decay curves of ε-polylysine-based organic room temperature phosphorescent material (NDA@ε-PL) at 496 nm and 530 nm are shown. By fitting, the phosphorescence lifetimes are found to be 622 ms at 496 nm and 627 ms at 530 nm.

[0051] Figure 3Images of the afterglow of ε-polylysine-based organic room-temperature phosphorescent material (NDA@ε-PL) at different time intervals after being excited by a 365nm UV lamp and then having the excitation source removed show that this room-temperature phosphorescent material has an ultra-long room-temperature phosphorescence property, with the green afterglow lasting up to 12 seconds at room temperature.

[0052] Example 3

[0053] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0054] Solution 1 is prepared by dissolving 2 mg of phosphor (6-amino-2-naphthic acid, abbreviated as ANA) in 5 ml of anhydrous ethanol; Solution 2 is prepared by dissolving 400 mg of ε-polylysine with an average molecular weight of 3800-4200 in 10 ml of deionized water; Solution 1 and Solution 2 are mixed at a mass ratio of phosphor to ε-polylysine of 1:200, stirred and heated to 60°C under helium protection, and reacted for 3 hours. After rotary evaporation and concentration, the mixture is dried in a vacuum oven at 70°C to obtain ε-polylysine-based organic room temperature phosphorescent material (ANA@ε-PL).

[0055] Figure 8 The phosphorescence spectrum of ε-polylysine-based organic room temperature phosphorescent material (ANA@ε-PL) was obtained, and its quantum yield was measured to be 18.84%.

[0056] Figure 9 The phosphorescence lifetime decay curve of ε-polylysine-based organic room temperature phosphorescent material (ANA@ε-PL) at 555 nm is shown. By fitting, its phosphorescence lifetime is found to be 642 ms.

[0057] Figure 3 Images of the afterglow of ε-polylysine-based organic room-temperature phosphorescent material (ANA@ε-PL) at different time intervals after being excited by a 365nm UV lamp and then having the excitation source removed show that this room-temperature phosphorescent material has an ultra-long room-temperature phosphorescence property, with a yellow afterglow that can be maintained for up to 6 seconds at room temperature.

[0058] Example 4

[0059] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0060] Solution 1 was prepared by dissolving 2 mg of phosphor (5-amino-2-naphthalenesulfonic acid, abbreviated as ANS) in 5 ml of anhydrous ethanol; Solution 2 was prepared by dissolving 300 mg of ε-polylysine with an average molecular weight of 3800-4200 in 10 ml of deionized water; Solution 1 and Solution 2 were mixed at a mass ratio of phosphor to ε-polylysine of 1:150, stirred and heated to 48°C under nitrogen protection, and reacted for 4 hours. After rotary evaporation and concentration, the mixture was dried in a vacuum oven at 60°C to obtain ε-polylysine-based organic room temperature phosphorescent material, named ANS@ε-PL.

[0061] Figure 10 The phosphorescence spectrum of ε-polylysine-based organic room temperature phosphorescent material (ANS@ε-PL) was obtained, and its quantum yield was measured to be 9.03%.

[0062] Figure 11 The phosphorescence lifetime decay curve of ε-polylysine-based organic room temperature phosphorescent material (ANS@ε-PL) at 596 nm is shown. By fitting, its phosphorescence lifetime is found to be 215 ms.

[0063] Figure 3 Images of the afterglow of ε-polylysine-based organic room-temperature phosphorescent material (ANS@ε-PL) at different time intervals after excitation by a 365nm UV lamp and removal of the excitation source show that this room-temperature phosphorescent material has an ultra-long room-temperature phosphorescence property, with an orange afterglow lasting for 4 seconds at room temperature. Furthermore, the material exhibits time-dependent emission wavelength shifts towards blue as time progresses.

[0064] Figure 12 Phosphorescence images of ε-polylysine-based organic room-temperature phosphorescent material (ANS@ε-PL) at different delay times.

[0065] Figure 13 To study the effects of ε-polylysine-based organic room-temperature phosphorescent materials (ANS@ε-PL) on different delay times (τ) d The phosphorescence spectrum under )

[0066] Example 5

[0067] A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials includes the following steps:

[0068] Solution 1 was prepared by dissolving 5 mg of phosphor (1-aminopyrene, abbreviated as Apyr) in 10 ml of anhydrous ethanol; Solution 2 was prepared by dissolving 850 mg of ε-polylysine with an average molecular weight of 3800-4200 in 15 ml of deionized water; Solution 1 and Solution 2 were mixed at a mass ratio of phosphor to ε-polylysine of 1:170, and stirred and heated to 50°C under nitrogen protection for 4 hours. After rotary evaporation and concentration, the mixture was dried in a vacuum oven at 60°C to obtain ε-polylysine-based organic room temperature phosphorescent material (Apyr@ε-PL).

[0069] Figure 14 The phosphorescence spectrum of ε-polylysine-based organic room temperature phosphorescent material (Apyr@ε-PL) was obtained, and its quantum yield was measured to be 6.60%.

[0070] Figure 15 The phosphorescence lifetime decay curve of ε-polylysine-based organic room temperature phosphorescent material (Apyr@ε-PL) at 635 nm is shown. By fitting, its phosphorescence lifetime is found to be 108 ms.

[0071] Figure 3 Images of the afterglow of the ε-polylysine-based organic room-temperature phosphorescent material (Apyr@ε-PL) at different time intervals after being excited by a 365nm UV lamp and then having the excitation source removed show that the room-temperature phosphorescent material has an ultra-long room-temperature phosphorescence property, with the red afterglow lasting for 3 seconds at room temperature.

[0072] Figure 16 The images show double-encryption (phosphorescence and fluorescence) models prepared from the ε-polylysine-based organic room-temperature phosphorescent materials obtained in Examples 1-5. The preparation methods of each example were followed until the reaction was complete, and after concentration and drying, the resulting solutions were written on. Specifically, the letter "O" was written with a solution of Daphe@ε-PL material; the letter "U" with a solution of NDA@ε-PL material; the letter "R" with a solution of ANA@ε-PL material; the letter "T" with a solution of ANS@ε-PL material; and the letter "P" with a solution of Apyr@ε-PL material, totaling "OURTP". Under natural light, the lettering is colorless. Under ultraviolet light (wavelength 365nm), the lettering appears as blue fluorescence. After the ultraviolet light is turned off, the encrypted information is displayed as phosphorescence. The five letters "OURTP" respectively exhibit afterglow colors of blue, green, yellow, orange, and red. This demonstrates that the ε-polylysine-based organic room-temperature phosphorescent material can be used for anti-counterfeiting encryption and as a room-temperature phosphorescent material.

[0073] As can be seen from the above examples and experimental results, the ε-polylysine-based organic room temperature phosphorescent materials prepared in each example all have high quantum yield, long lifetime room temperature phosphorescence properties, and encryption and anti-counterfeiting effects; at the same time, Daphe@ε-PL material is excitation-dependent, and ANS@ε-PL material is time-dependent.

[0074] This invention obtains a pure organic polymer material with high-efficiency, long-lifetime room-temperature phosphorescence properties by doping pure organic phosphors into ε-polylysine with a tight network structure, thereby achieving a significant extension of phosphorescence lifetime and an increase in phosphorescence quantum yield.

Claims

1. A method for preparing ε-polylysine-based organic room-temperature phosphorescent materials, characterized by the following steps: Solution 1 is prepared by dissolving a phosphor in anhydrous ethanol; Solution 2 is prepared by dissolving ε-polylysine with an average molecular weight of 3800-4200 in deionized water; Solution 1 and Solution 2 are mixed at a mass ratio of phosphor to ε-polylysine of 1:100-200, and stirred and heated to 45-60°C under argon, helium or nitrogen protection for 3-5 hours. After rotary evaporation and concentration, the mixture is dried to obtain an ε-polylysine-based organic room temperature phosphorescent material; The phosphor is 9,10-diaminophenanthrene, 2,3-naphthalenedicarboxylic acid, 6-amino-2-naphthoic acid, 5-amino-2-naphthalenesulfonic acid or 1-aminopyrene.

2. The preparation method according to claim 1, characterized in that... Drying is carried out in a vacuum oven at a temperature of 60–80°C.

3. The ε-polylysine-based organic room-temperature phosphorescent material prepared by the preparation method of claim 1 or 2.

4. The application of the ε-polylysine-based organic room-temperature phosphorescent material of claim 3 as an anti-counterfeiting and encryption material.

5. The application of the ε-polylysine-based organic room-temperature phosphorescent material of claim 3 as a room-temperature phosphorescent material.

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