A room-temperature phosphorescent material, a room-temperature phosphorescent ink, its preparation method and application
By combining plant polyphenols and boric acid to form dynamic borate ester bonds, a highly efficient room-temperature phosphorescent material and ink were prepared. This solved the problems of low phosphorescence efficiency and short luminescence duration of existing materials, achieving long-term luminescence in both bright and dark environments, and reducing production costs. It is suitable for printing, optical anti-counterfeiting, information encryption and OLED applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NORTHEAST FORESTRY UNIV
- Filing Date
- 2026-02-02
- Publication Date
- 2026-06-02
AI Technical Summary
Existing organic room temperature phosphorescent materials suffer from problems such as low phosphorescence efficiency, short luminescence duration, and insufficient overall brightness in practical applications, making it difficult to meet the multiple needs of high-end anti-counterfeiting, information encryption, and other scenarios.
A room-temperature phosphorescent material and ink were prepared by combining plant polyphenols and boric acid to form dynamic borate ester bonds, thereby enhancing phosphorescence emission performance. The material includes a combination of ellagic acid, tannic acid or gallic acid and boric acid. The pH value was adjusted by adding alkaline substances, and the material was dissolved in a solvent and ultrasonically treated.
The prepared room-temperature phosphorescent materials and inks exhibit ultra-long phosphorescence lifetime and high brightness at room temperature, and can continuously emit light for a long time in both bright and dark environments. They have good visibility and practicality, and the preparation process is simple and low-cost, making them suitable for a variety of printing scenarios.
Smart Images
Figure CN122127973A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical materials technology, specifically to room temperature phosphorescent materials, room temperature phosphorescent inks, their preparation methods, and applications. Background Technology
[0002] In the field of optical anti-counterfeiting materials, fluorescent materials are widely used due to their excellent luminescence performance and high signal intensity. However, these materials have some inherent limitations, such as short luminescence lifetime and easy signal attenuation or masking under strong light or complex background noise interference, which limits their stability and reliability in practical anti-counterfeiting applications. In contrast, room temperature phosphorescent materials exhibit many significant advantages, such as low toxicity, high environmental friendliness, high signal-to-noise ratio, and large Stokes shift. These characteristics enable them to maintain good recognizability and stability even in complex environments. Therefore, room temperature phosphorescent materials have been widely studied and applied in many cutting-edge fields such as information encryption, high-security anti-counterfeiting labels, biosensing, and bioimaging, showing good development prospects and application potential.
[0003] In recent years, organic room-temperature phosphorescent (RTP) materials have become a hot research area in the development of next-generation anti-counterfeiting inks due to their outstanding characteristics such as strong structural designability, relatively simple synthesis routes, wide availability of raw materials, and environmental friendliness, demonstrating huge market potential and application prospects. However, despite the increasingly active research in this field, existing organic phosphorescent inks still generally suffer from many key problems in practical applications, such as low phosphorescence efficiency, short luminescence duration, and insufficient overall brightness. These problems severely restrict the widespread use of such materials in high-end anti-counterfeiting and information encryption scenarios, making it difficult for current products to simultaneously meet the multiple demands of the anti-counterfeiting industry for materials with long lifespan, high brightness, easy identification, and low-cost preparation and application.
[0004] Therefore, in response to these bottlenecks in existing technologies, there is an urgent need to develop a new type of phosphorescent ink with superior overall performance. This material should have a longer phosphorescence lifetime, higher luminescence intensity, and good processability and adaptability to promote the wider application of organic room temperature phosphorescence technology in anti-counterfeiting and related fields. Summary of the Invention
[0005] In order to solve one of the above-mentioned technical problems in the prior art, the present invention provides a room temperature phosphorescent material, a room temperature phosphorescent ink, a preparation method thereon, and its application.
[0006] In a first aspect, the present invention provides a room temperature phosphorescent material comprising plant polyphenols and boric acid.
[0007] In this invention, the plant polyphenols include, but are not limited to, one or more of ellagic acid, tannic acid, and gallic acid. In some embodiments, the plant polyphenols include ellagic acid. In some embodiments, the plant polyphenols include ellagic acid and one or two selected from tannic acid and gallic acid. In some embodiments, the plant polyphenol is ellagic acid.
[0008] This invention discovers that when plant polyphenols and boric acid are combined, the plant polyphenols act as chromophores and the boric acid acts as a matrix. The two can form dynamic borate ester bonds, which further enhances the phosphorescence emission performance and gives the material an ultra-long phosphorescence lifetime (for example, the phosphorescence afterglow of the combination of ellagic acid and boric acid lasts for more than 10 seconds, showing excellent phosphorescence emission performance).
[0009] According to some embodiments of the present invention, the mass ratio of the plant polyphenols to boric acid is 1:(7.5-20), for example, 1:7.5, 1:8.5, 1:9.5, 1:10.5, 1:11.5, 1:12.5, 1:13.5, 1:14.5, 1:15.5, 1:16.5, 1:17.5, 1:18.5, 1:19.5, 1:20, etc.
[0010] In this application, too little boric acid will reduce the phosphorescence lifetime of the material, while too much boric acid will not help extend the phosphorescence lifetime of the material. Therefore, the mass ratio of plant polyphenols to boric acid is best controlled within a suitable range.
[0011] In some embodiments, the mass ratio of the plant polyphenols to boric acid is 1:(10.5-20). In some embodiments, the mass ratio of the plant polyphenols to boric acid is 1:(12.5-15).
[0012] According to some embodiments of the present invention, the room temperature phosphorescent material has a phosphorescence emission wavelength of 510-550 nm corresponding to an excitation wavelength of 240-400 nm.
[0013] According to some embodiments of the present invention, the fluorescence spectrum of the room-temperature phosphorescent material has a peak at 490±10 nm.
[0014] In a second aspect, the present invention provides a room temperature phosphorescent ink, which includes the room temperature phosphorescent material and solvent described in the first aspect of the present invention; or, the raw materials for its preparation include the room temperature phosphorescent material and solvent described in the first aspect of the present invention.
[0015] According to some embodiments of the present invention, the solvent includes water.
[0016] According to some embodiments of the present invention, the volume ratio of the solvent to the mass of the plant polyphenols in the room-temperature phosphorescent material is (100-500) mL:1g, for example, 100mL:1g, 110mL:1g, 120mL:1g, 130mL:1g, 140mL:1g, 150mL:1g, 180mL:1g, 200mL:1g, 220mL:1g, 250mL:1g, 280mL:1g, 300mL:1g, 320mL:1g, 350mL:1g, 380mL:1g, 400mL:1g, 420mL:1g, 450mL:1g, 480mL:1g, 500mL:1g, etc. In some embodiments, the volume ratio of the solvent to the mass of the plant polyphenols in the room-temperature phosphorescent material is (100-200) mL:1g.
[0017] According to some embodiments of the present invention, the room-temperature phosphorescent ink and / or its preparation raw materials further include an alkaline substance. The alkaline substance described in the present invention includes, but is not limited to, alkali metal hydroxides, such as one or both of sodium hydroxide and potassium hydroxide.
[0018] In this invention, the purpose of adding alkaline substances is to make plant polyphenols dissolve better in the solvent. Generally, plant polyphenols can be fully dissolved in water under conditions of pH ≥ 8.
[0019] According to some embodiments of the present invention, the room temperature phosphorescent ink has a pH of 8 or higher, for example, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, etc. In some embodiments, the room temperature phosphorescent ink has a pH of 8-10.
[0020] Thirdly, the present invention provides a method for preparing room temperature phosphorescent ink as described in the second aspect of the present invention, comprising the following steps: dissolving the room temperature phosphorescent material in the solvent to obtain the room temperature phosphorescent ink.
[0021] According to some embodiments of the present invention, the dissolution is carried out in the presence of the alkaline substance.
[0022] According to some embodiments of the present invention, the dissolution is carried out under ultrasonic conditions.
[0023] According to some embodiments of the present invention, the dissolution includes: mixing the plant polyphenols, boric acid and the solvent, then adding the alkaline substance to obtain a mixture; and subjecting the mixture to ultrasonic treatment to obtain the room temperature phosphorescent ink.
[0024] The alkaline substances described in this invention include, but are not limited to, alkali metal hydroxides and alkali metal carbonates, such as one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. In some embodiments, the amount of the alkaline substance used satisfies the following condition: the pH of the solvent is 8 or higher, for example, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, 12, 12.5, 13, 13.5, 14, etc., preferably 8-10.
[0025] According to some embodiments of the present invention, the melting temperature is 15-45°C, for example 15°C, 18°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, etc., preferably 20-30°C.
[0026] Fourthly, the present invention provides the application of room temperature phosphorescent materials as described in the first aspect, or room temperature phosphorescent inks as described in the second aspect, or room temperature phosphorescent inks obtained by the preparation method as described in the third aspect, in printing, optical anti-counterfeiting, information encryption, and OLEDs (organic light-emitting devices).
[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. The room-temperature phosphorescent material and ink provided by this invention exhibit excellent phosphorescence performance at room temperature, with a phosphorescence afterglow exceeding 10 seconds, demonstrating superior long-lasting luminescence characteristics, significantly better than traditional materials. Simultaneously, the ink possesses high brightness characteristics; its luminescence effect remains clearly visible even under bright ambient light, enabling it to continuously emit light for extended periods in both bright and dark environments, greatly enhancing visibility and practicality in applications.
[0028] 2. The room-temperature phosphorescent material of this invention has a simple composition, with widely available and inexpensive raw materials. Using ellagic acid and other plant polyphenols and boric acid as the main raw materials, these are dissolved in a solvent through simple mechanical mixing, enabling large-scale preparation of printable ink. The preparation method of room-temperature phosphorescent ink not only uses readily available raw materials and has a simple operation process, but also requires no complex equipment or stringent conditions. It can produce ink products suitable for various printing scenarios at low cost, high efficiency, and stable output, possessing good application prospects and industrialization potential. Attached Figure Description
[0029] Figure 1 The phosphorescence emission spectrum and phosphorescence lifetime test results of the ink in Example 1 under room temperature conditions are shown; excitation wavelength = 365 nm.
[0030] Figure 2 The fluorescence spectrum and fluorescence lifetime test results of the ink of Example 1 under room temperature conditions are shown; excitation wavelength = 365 nm.
[0031] Figure 3The normalized fluorescence-phosphorescence spectrum of the ink of Example 1 under room temperature conditions is shown.
[0032] Figure 4 The excitation-phosphorescence mapping emission spectra of the ink of Example 1 at different excitation wavelengths are shown.
[0033] Figure 5 The time-resolved spectrum of the ink of Example 1 is shown.
[0034] Figure 6 A photograph of the ink from Example 1 is shown.
[0035] Figure 7 The fluorescence and phosphorescence images of the ink-printed sample of Example 1 are shown under bright field.
[0036] Figure 8 The following images show the fluorescence and phosphorescence of the ink-printed sample of Example 1 in a dark field.
[0037] Figure 9 The phosphorescence images of the inks prepared in Examples 1, 4, 5 and Comparative Example 1 at different amounts of boric acid are shown. Detailed Implementation
[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. The specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way.
[0039] Unless otherwise defined, the technical terms used in the following embodiments and comparative examples have the same meaning as commonly understood by those skilled in the art to which this invention pertains.
[0040] Unless otherwise specified, the reagents used in the following examples and comparative examples are all conventional biochemical reagents; the raw materials, instruments and equipment used in the following examples and comparative examples can all be obtained by purchasing them from the market or by existing methods; unless otherwise specified, the reagent dosages are all reagent dosages used in conventional experimental operations; unless otherwise specified, the experimental methods are all conventional methods.
[0041] In this invention, "room temperature" refers to 20-30℃.
[0042] In the following experiments of this invention, the CAS numbers of ellagic acid, tannic acid, gallic acid, boric acid, and boric acid used are 476-66-4, 1401-55-4, 149-91-7, and 10043-35-3, respectively.
[0043] Example 1: Preparation of Ellagic Acid Room Temperature Phosphorescent Ink
[0044] Ellagic acid solid (1g) and boric acid solid (12.5g) were mixed and added to water (100 mL). Sodium hydroxide solid (1g) was then added to the solution under ultrasonication (to adjust the pH to 8-9). The mixture was ultrasonicated until no precipitate was observed, resulting in a printable room-temperature phosphorescent ink (ink photo shown). Figure 6 (As shown).
[0045] Example 2: Preparation of Tannic Acid Room Temperature Phosphorescent Ink Tannic acid solid (1g) and boric acid solid (12.5g) were mixed and added to water (100 mL). Sodium hydroxide solid (1g) was added to the solution under sonication (to make the solution pH 8-9). The mixture was sonicated until no precipitate was found, resulting in a printable room temperature phosphorescent ink.
[0046] Example 3: Preparation of gallic acid room temperature phosphorescent ink Gallic acid solid (1g) and boric acid solid (12.5g) were mixed and added to water (100 mL). Sodium hydroxide solid (1g) was added to the solution under sonication (to make the solution pH 8-9). The mixture was sonicated until no precipitate was found, resulting in a printable room temperature phosphorescent ink.
[0047] Example 4 The ink preparation method is the same as in Example 1, except that the amount of boric acid added is adjusted to 7.5 g.
[0048] Example 5 The ink preparation method is the same as in Example 1, except that the amount of boric acid added is adjusted to 20 g.
[0049] Comparative Example 1 The only difference from Example 1 is that boric acid is not added.
[0050] Test Example 1: Phosphorescence Emission Spectrum and Phosphorescence Lifetime Test The phosphorescence spectrum and lifetime of the ink were tested using an Edinburgh steady-state / transient fluorescence spectrometer FLS1000. The specific method involved dropping a suitable amount of ink onto filter paper, drying it in an oven, and then placing it in a mold to test the phosphorescence spectrum and lifetime.
[0051] The ink of Example 1 exhibits the following phosphorescence emission spectrum at room temperature with an excitation wavelength of 365 nm: Figure 1 As shown in a; the phosphorescence lifetime test results are as follows: Figure 1 As shown in b. From Figure 1 It can be seen that the phosphorescence intensity of the ink can reach 4×10⁻⁶. 6 The phosphorescence lifetime of au is up to 1294.09 ms, and the phosphorescence afterglow is up to 12 s.
[0052] The phosphorescence intensity and lifetime of the inks prepared in Examples 1, 2, 3, 4, 5 and Comparative Example 1 are listed in Table 1 below.
[0053] Table 1
[0054] As can be seen, compared with the inks prepared by combining tannic acid and gallic acid with boric acid in Examples 2-3 respectively, the ink prepared by combining ellagic acid with boric acid in Example 1 has higher phosphorescence intensity and lifespan.
[0055] Phosphorescent images of the inks prepared in Examples 1, 4, 5 and Comparative Example 1 are shown below. Figure 9 As shown in Table 1, the ink with the longest room temperature phosphorescence lifespan (1.29 seconds) and afterglow (12 s) is obtained when the boric acid content is 12.5 g, i.e., the mass ratio of ellagic acid to boric acid is 1:12.5 (g:g). Increasing the amount of boric acid added does not significantly extend the lifespan of the room temperature phosphorescent ink.
[0056] Therefore, in this invention, the mass ratio of ellagic acid to boric acid is preferably in the range of 1:12.5.
[0057] Test Example 2: Fluorescence Spectroscopy and Fluorescence Lifetime Test
[0058] The fluorescence spectrum and fluorescence lifetime of the ink were tested using an Edinburgh steady-state / transient fluorescence spectrometer FLS1000. The specific method involved dropping an appropriate amount of ink onto filter paper, drying it in an oven, placing it in a mold, and then testing the fluorescence spectrum and lifetime.
[0059] The fluorescence spectrum of the ink in Example 1 at room temperature with an excitation wavelength of 365 nm is as follows: Figure 2 As shown in a; the fluorescence lifetime test results are as follows: Figure 2 As shown in b. From Figure 2 It can be seen that the fluorescence intensity is 2.7 × 10⁻⁶. 5 au has a fluorescence lifetime of 8.79 ns.
[0060] The normalized fluorescence-phosphorescence spectrum of the ink in Example 1 at room temperature is as follows: Figure 3 As shown, the peak of the fluorescence spectrum (black line) of the ink is located at 490 nm. Correspondingly, under room temperature conditions and irradiation by a 365 nm ultraviolet lamp, the fluorescence appears blue-white, and the peak of the phosphorescence spectrum (red line) is located at 530 nm. After the ultraviolet lamp is turned off, it emits yellow-green room temperature phosphorescence. There is a large shift between the spectral peaks.
[0061] Test Example 3: Excitation-phosphorescence mapping spectrum The excitation-phosphorescence mapping spectrum of the ink was measured using an Edinburgh steady-state / transient fluorescence spectrometer FLS1000. The specific method involved dropping an appropriate amount of ink onto filter paper, drying it in an oven, placing it in a mold, and then measuring the excitation-phosphorescence mapping spectrum.
[0062] The excitation-phosphorescence mapping spectra of the ink in Example 1 at different excitation wavelengths are as follows: Figure 4 As shown, it can be seen that its phosphorescence emission is sensitive to the excitation wavelength: when the excitation wavelength increases from 240 nm to 400 nm, the phosphorescence emission wavelength redshifts from 510 nm to 550 nm.
[0063] Test Example 4: Time-Resolved Spectrum Test method: The time-resolved spectrum of the ink was measured using an Edinburgh steady-state / transient fluorescence spectrometer FLS1000. Specifically, an appropriate amount of ink was dropped onto filter paper, dried in an oven, and then placed in a mold to measure the time-resolved spectrum.
[0064] The time-resolved spectrum of the ink in Example 1 is as follows: Figure 5 As shown, the ink has a long-lasting and stable afterglow emission characteristic, and can maintain weak phosphorescence emission for up to about 3 seconds at the same emission wavelength.
[0065] Test Example 5: Printing Performance Test The ink prepared in Example 1 was used for printing. The printing device was an HP DeskJet 2332 printer, and the ink cartridge used was an 805XL.
[0066] Printing results under bright field are as follows Figure 7 As shown, the sample printed with the ink of Example 1 of the present invention has almost no visible printed pattern under bright field conditions. Only after ultraviolet excitation does it exhibit obvious long afterglow emission under bright field conditions, and the pattern is clearly visible, indicating that the ink also has a good anti-counterfeiting effect.
[0067] Printing results under dark conditions are as follows Figure 8 As shown, the sample printed with the ink of Example 1 of the present invention exhibits significant long afterglow emission under dark conditions after ultraviolet excitation.
[0068] In summary, the plant polyphenol room-temperature phosphorescent ink developed in this invention exhibits superior performance, possessing not only an ultra-long phosphorescence lifetime but also extremely high luminescence brightness. Its phosphorescence lifetime is significantly better than traditional materials, enabling it to continuously emit light for extended periods in both bright and dark environments, greatly enhancing visibility and practicality in applications. Furthermore, the ink's preparation process is simple and easy to implement, requiring no complex equipment or stringent conditions, significantly lowering the technical barriers to production. In addition, the low cost of raw materials results in significant savings in overall production costs, making it suitable for large-scale industrial production and possessing broad market prospects and application potential.
[0069] The technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made in accordance with the technical solutions of the present invention fall within the protection scope of the present invention.
Claims
1. A room-temperature phosphorescent material comprising plant polyphenols and boric acid.
2. The room-temperature phosphorescent material according to claim 1, characterized in that, The plant polyphenols include one or more of ellagic acid, tannic acid, and gallic acid, preferably ellagic acid.
3. The room-temperature phosphorescent material according to claim 1 or 2, characterized in that, The mass ratio of plant polyphenols to boric acid is 1:(7.5-20), preferably 1:(10.5-20), and more preferably 1:(12.5-15).
4. The room-temperature phosphorescent material according to any one of claims 1-3, characterized in that, The room-temperature phosphorescent material has a phosphorescence emission wavelength of 510-550 nm corresponding to an excitation wavelength of 240-400 nm; and / or The fluorescence spectrum of the room-temperature phosphorescent material has a peak at 490±10 nm.
5. A room temperature phosphorescent ink comprising the room temperature phosphorescent material and solvent as described in any one of claims 1-4; or, the raw materials for its preparation comprising the room temperature phosphorescent material and solvent as described in any one of claims 1-4.
6. The room temperature phosphorescent ink according to claim 5, characterized in that, The solvent includes water; and / or the volume ratio of the solvent to the mass ratio of the plant polyphenols in the room temperature phosphorescent material is (100-500) mL:1 g, preferably (100-200) mL:1 g.
7. The room temperature phosphorescent ink according to claim 5 or 6, characterized in that, The room-temperature phosphorescent ink and / or its raw materials further include an alkaline substance; preferably, the alkaline substance includes one or more of alkali metal hydroxides and alkali metal carbonates, more preferably one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; and / or, The room temperature phosphorescent ink has a pH of 8 or higher, preferably 8-10.
8. A method for preparing a room-temperature phosphorescent ink as described in any one of claims 5-7, comprising the following steps: The room temperature phosphorescent material is dissolved in the solvent to obtain the room temperature phosphorescent ink.
9. The preparation method according to claim 8, characterized in that, The dissolution is carried out in the presence of the alkaline substance; preferably, the amount of the alkaline substance is such that the pH of the solvent is 8 or higher, preferably 8-10; and / or The dissolution is performed under ultrasonic conditions; and / or The melting temperature is 15-45℃, preferably 20-30℃.
10. The application of the room temperature phosphorescent material as described in any one of claims 1-4, or the room temperature phosphorescent ink as described in any one of claims 5-7, or the room temperature phosphorescent ink obtained by the preparation method as described in any one of claims 8-9, in printing, optical anti-counterfeiting, information encryption, and OLED.