Ultralow-doped high-efficiency room-temperature phosphorescent material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of luminescent materials, and particularly relates to an ultralow-doped efficient room-temperature phosphorescent material as well as a preparation method and application thereof. According to the invention, a phenyl [2-phenyl-1H-benzo [d] imidazole-5-yl] ketone derivative (PBM-R) molecule is used as an energy acceptor, and is doped with main materials such as N-methyl-4-bromobenzamide (BMB) and the like (an energy transfer carrier). After the two compounds are simply mixed and mechanically ground, triplet-triplet energy transfer (TTET) can be started, so that organic room-temperature phosphorescence emission is realized. It is worthy of notice that the phosphorescent material can maintain significant phosphorescent emission even at a low object doping level (the mass ratio of the subject to the object is as high as 10000: 1), so that the material consumption is significantly reduced and the photophysical stability is improved. The doping system is further applied to various information storage and encryption methods, and the potential of multi-scene application of the doping system is highlighted.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, specifically relating to an ultra-low doped, high-efficiency room-temperature phosphorescent material, its preparation method, and its applications. Background Technology

[0002] Organic room-temperature phosphorescent (RTP) materials have attracted much attention due to their potential applications in flexible electronics, bioimaging, and information security. However, an inherent limitation of RTP materials is that their triplet excitons are susceptible to molecular vibrations, oxygen quenching, and nonradiative transitions, making it difficult to obtain high quantum yields and long lifetimes of phosphorescence at room temperature. Strategies such as introducing heavy or heteroatoms, crystal engineering, supramolecular assembly, and host-guest doping can effectively improve inter-system crossover efficiency and suppress nonradiative deactivation of triplet excitons.

[0003] Among them, host-guest doping systems have attracted widespread attention due to their advantages such as simple preparation, low cost, wide range of molecular structures, and controllable performance. Furthermore, organic room-temperature phosphorescence has broad application prospects in fields such as data anti-counterfeiting encryption, display lighting, bioimaging, and chemical sensors.

[0004] However, in cutting-edge applications such as information security and advanced anti-counterfeiting, traditional highly doped RTP materials, due to their high doping concentration, have phosphorescence spectra that are easily reverse-engineered and cannot achieve "ultra-high capacity encoding." In the fields of bioimaging and diagnosis, the potential cytotoxicity and metabolic burden caused by high doping concentration limit their application in long-term in vivo tracing. Therefore, developing RTP materials that still possess high efficiency, long lifetime, and high stability at ultra-low doping concentrations remains a pressing technical problem to be solved in this field. Summary of the Invention

[0005] To address the problems of existing technologies, this invention provides an ultra-low doped, high-efficiency room-temperature phosphorescent material, its preparation method, and its applications.

[0006] The phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative is used as a guest material in host-guest doped organic room-temperature phosphorescent materials, and the structure of the phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative is shown in Formula I: Formula I R is selected from hydrogen, CN, halogen, methyl, methoxy, halogen-substituted methyl, and dimethylamino.

[0007] Preferably, R is selected from hydrogen, CN, Br, methyl, methoxy, trifluoromethyl, and dimethylamino.

[0008] Preferably, the host material of the host-guest doped organic room temperature phosphorescent material is selected from at least one of N-methyl-4-bromobenzamide or benzophenone.

[0009] This invention also provides an ultra-low doped, high-efficiency room-temperature phosphorescent material, comprising a host material and a guest material, wherein the host material is selected from at least one of N-methyl-4-bromobenzamide or benzophenone; and the guest material is selected from a phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative, the structure of which is shown in Formula I: Formula I R is selected from hydrogen, CN, halogen, methyl, methoxy, halogen-substituted methyl, and dimethylamino.

[0010] Preferably, the mass ratio of the main material to the object material is (100-100000):1.

[0011] Preferably, the mass ratio of the main material to the object material is (1000-10000):1.

[0012] Preferably, the mass ratio of the main material to the object material is 1000:1.

[0013] Preferably, R is selected from hydrogen, CN, Br, methyl, methoxy, trifluoromethyl, and dimethylamino.

[0014] The present invention also provides a method for preparing the above-mentioned ultra-low doped high-efficiency room temperature phosphorescent material, comprising: adding the host material and the guest material to an organic solvent, and then grinding and evaporating the organic solvent to obtain phosphorescent material powder.

[0015] This invention also provides the use of the above-mentioned ultra-low doped, high-efficiency room-temperature phosphorescent material in the preparation of data encryption products or information storage products. The product can take the form of inks, markings, coatings, films, fibers, paper, microcapsule / microsphere additives, time-resolved dynamic codes, 3D-printed encryption structures, etc.

[0016] This invention marks the first discovery of a class of phenyl[2-phenyl-1H-benzis[d]imidazol-5-yl]methyl ketone derivatives that can serve as guest materials in host-guest doped organic room-temperature phosphorescent materials. Organic room-temperature phosphorescent materials prepared from these derivatives maintain significant phosphorescence emission even at relatively low guest doping levels (host-guest mass ratios as high as 10000:1), thereby significantly reducing material consumption and improving photophysical stability. Specifically, the BMB / PBM-R doped system achieves a phosphorescence lifetime of 433 ms and a phosphorescence quantum yield of 48%. This organic room-temperature phosphorescent material has broad application prospects in advanced information storage and other fields, and its time-dependent characteristics can provide advanced anti-counterfeiting encryption technology.

[0017] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions, or alterations can be made without departing from the basic technical concept of the present invention.

[0018] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0019] Figure 1 Structural diagram of a host-guest doped system; Figure 2 Phosphorescence spectra of different host structures and their respective doping with guest PBM-CN (λ) ex (365 nm, Delay: 0.1 s); Figure 3 Phosphorescence spectra of BMB and PBM-R doped materials (λ) ex (365 nm, Delay: 0.1 s); Figure 4 Fluorescence spectra of BMB and PBM-R doped materials; Figure 5 Images of BMB and PBM-R doped under 365 nm UV light irradiation and off; Figure 6 Fluorescence spectra of BMB and PBM-CN with different doping ratios (λ) ex (365 nm, Delay: 0.1 s); Figure 7 Phosphorescence spectra of BMB and PBM-CN with different doping ratios (λ) ex (365 nm, Delay: 0.1 s); Figure 8Images of BMB and PBM-CN with different doping ratios under 365 nm UV light irradiation and with the light off; Figure 9 PXRD patterns of BMB and BMB / PBM-CN; Figure 10 Phosphorescence lifetime diagram (λ) of BMB and PBM-N(CH3)2 (1000:1) at room temperature ex (365 nm, Delay: 0.1 s); Figure 11 Diagram of BMB and PBM-R information encryption applications. Detailed Implementation

[0020] In the following examples and experimental cases, reagents and raw materials not specifically described are all commercially available products.

[0021] Explanation of abbreviations: BMB: N-methyl-4-bromobenzamide; PBM-R: A phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative; DCM: Dichloromethane.

[0022] Example 1 Synthesis of PBM-CN Using 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-cyanobenzaldehyde (473 mg, 3.6 mmol, 1.2 equivalent) as starting materials, a 250 mL round-bottom flask containing 10 mL of DMF was added. The mixture was stirred at 120 °C for 6 hours. After the reaction was completed, the reaction was quenched with water and cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid.

[0023] Yield: 777 mg (67.6%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.60 (d, J = 24.6 Hz, 1H), 8.37 (d, J = 8.2 Hz, 2H), 8.07 (dt, J = 8.3, 4.1 Hz, 3H), 7.95–7.84 (m, 1H), 7.76 (p, J= 8.2, 7.5 Hz, 3H), 7.69 (t, J = 7.2 Hz, 1H), 7.59 (t, J = 7.6 Hz, 2H). Example 2 Synthesis of PBM-Br Using 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-bromobenzaldehyde (666 mg, 3.6 mmol, 1.2 equivalent) as starting materials, a 250 mL round-bottom flask containing 10 mL of DMF was added. The mixture was stirred at 120 °C for 6 hours. After the reaction was completed, the reaction was quenched with water and cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid.

[0024] Yield: 740 mg (65.4%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.40 (d, J = 25.8 Hz, 1H), 8.14 (d, J = 8.2 Hz, 2H), 7.95 (d, J = 59.5 Hz, 1H), 7.79 (dd, J = 19.5, 7.8Hz, 4H), 7.68 (t, J = 7.5 Hz, 2H), 7.58 (t, J = 7.6 Hz, 2H). Example 3 Synthesis of PBM-N(CH3)2 Using 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-dimethylaminobenzaldehyde (537 mg, 3.6 mmol, 1.2 equivalent) as starting materials, a 250 mL round-bottom flask containing 10 mL of DMF was added. The mixture was stirred at 120 °C for 6 hours. After the reaction was completed, the reaction was quenched with water and cooled to room temperature. The mixture was then extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid.

[0025] Yield: 661 mg (64.5%). 1 H NMR (500 MHz, DMSO-) d 6) δ 12.91 (d, J = 39.1 Hz, 1H), 8.02 (d, J = 6.7 Hz, 2H), 7.96–7.72 (m, 3H), 7.70–7.54 (m, 5H), 6.85 (d, J =8.5 Hz, 2H), 3.01 (s, 6H). Example 4 Synthesis of PBM-Me Starting with 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-tolualdehyde (433 mg, 3.6 mmol, 1.2 equivalent), a mixture was added to a 250 mL round-bottom flask containing 10 mL of DMF. The mixture was stirred at 120 °C for 6 hours. After the reaction was complete, the mixture was quenched with water and cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid.

[0026] Yield: 621 mg (66.3%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.22 (s, 1H), 8.09 (d, J = 7.7 Hz, 2H), 7.94 (d, J = 43.9 Hz, 1H), 7.76 (d, J= 7.0 Hz, 2H), 7.67 (d, J =7.4 Hz, 3H), 7.58 (t, J = 7.8 Hz, 2H), 7.39 (d, J = 7.8 Hz, 2H), 2.39 (s, 3H). Example 5 Synthesis of PBM-H Compound PBM-H was prepared from 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and benzaldehyde (366 mL, 3.6 mmol, 1.2 equivalent) in a 250 mL round-bottom flask containing 10 mL of DMF. The mixture was stirred at 120 °C for 6 hours. After the reaction was complete, the mixture was quenched with water and cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The solution was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid.

[0027] Yield: 734 mg (68.4%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.32 (d, J = 27.6 Hz,1H), 8.28–8.14 (m, 2H), 7.96 (d, J = 57.6 Hz, 1H), 7.84–7.64 (m, 5H), 7.58(ddt, J = 14.6, 11.1, 5.1 Hz, 5H). Example 6 Synthesis of PBM-CF3 Starting with 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-(trifluoromethyl)benzaldehyde (627 mg, 3.6 mmol, 1.2 equivalent), a mixture was added to a 250 mL round-bottom flask containing 10 mL of DMF. The mixture was stirred at 120 °C for 6 hours. After the reaction was complete, the mixture was quenched with water and cooled to room temperature. The mixture was then extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid. Yield: 655 mg (67.6%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.57 (d, J = 24.4 Hz, 1H), 8.41 (d, J = 8.0Hz, 2H), 8.05 (s, 1H), 8.01–7.88 (m, 2H), 7.88–7.64 (m, 5H), 7.59 (d, J = 7.6Hz, 2H). Example 7 Synthesis of PBM-OMe Starting with 3,4-diaminobenzophenone (637 mg, 3 mmol, 1.0 equivalent) and 4-anisaldehyde (490 mg, 3.6 mmol, 1.2 equivalent), the mixture was added to a 250 mL round-bottom flask containing 10 mL of DMF. The mixture was stirred at 120 °C for 6 hours. After the reaction was complete, the reaction was quenched with water and cooled to room temperature. The mixture was extracted with ethyl acetate, and the organic phase was dried over anhydrous sodium sulfate. The organic phase was purified by column chromatography (PE / EA = 3:1, v / v) and concentrated under reduced pressure to give a yellow solid. Yield: 766 mg (64.8%). 1 H NMR (500 MHz, DMSO-) d 6) δ 13.14 (d, J = 31.2 Hz, 1H), 8.15 (d, J = 8.4 Hz, 2H),8.00–7.72 (m, 3H), 7.72–7.62 (m, 3H), 7.58 (t, J = 7.7 Hz, 2H), 7.14 (d, J= 5.3Hz, 2H), 3.85 (s, 3H). Example 8 Preparation of ultra-low doped, high-efficiency room-temperature phosphorescent materials: 100 mg of host material (e.g., N-methyl-4-bromobenzamide) and 1 mg of guest material (e.g., phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative, PBM-R) were placed together in an agate mortar with a diameter of 5 cm, and dichloromethane (20 µL) was added. After grinding and solvent evaporation, RTP powder was obtained.

[0028] Among them, PBM-R refers to PBM-CN, PBM-Br, PBM-N(CH3)2, PBM-Me, PBM-H, PBM-CF3, and PBM-OMe prepared through Examples 1-7.

[0029] The phosphorescent materials used in the following experiments were all prepared according to the method of this embodiment, except that the host and guest materials in the preparation method were replaced according to a specific host-guest system.

[0030] Example 9 Different host and guest materials were selected and test samples were prepared according to the method in Example 8 for photophysical performance testing. Different guest materials were ground with the host to obtain a series of doped systems for testing. First, different guest molecules were prepared at a host / guest ratio of 1000:1 (mass ratio).

[0031] The test results of phosphorescence spectra of doped systems with different host and guest elements are as follows: Figure 2 , Figure 3 As shown, it can be seen that using N-methyl-4-bromobenzamide (BMB) or benzophenone (BP) as the host material and PBM-R as the guest material can achieve better phosphorescence luminescence effect.

[0032] Examining the afterglow of these materials, such as Figure 4 , Figure 5 As shown, BMB / PBM-N(CH3)2 has the longest afterglow time.

[0033] Example 10 Determination of fluorescence and phosphorescence of BMB / PBM-R doped with different mass ratios: Given the significant influence of guest molecule concentration on the photophysical properties of doped materials, host-guest systems with BMB / PBM-R mass ratios ranging from 1:1 to 100,000:1 were prepared according to the method in Example 8. The photophysical properties of these host-guest doped systems with different mass ratios were then tested. The photoluminescence spectra of the doped systems are shown below. Figure 6 ), Figure 7 Phosphorescence spectrum, such as Figure 8 As shown, when the doping concentration is 1000:1, the phosphorescence brightness of the material is the best, and the phosphorescence lifetime is relatively long (e.g., Figure 10 Therefore, in subsequent studies, the doping system was always used at a concentration of 1000:1, which not only provides good phosphorescence performance but also reflects the luminescence characteristics of the guest phosphorescence.

[0034] Example 11 Powder X-ray diffraction (PXRD) studies: Powder X-ray diffraction (PXRD) studies were conducted on BMB and BMB / PBM-CN doped systems, and the results showed that the host and guest components had high crystallinity. Figure 9 The peak shapes of the doped materials are basically similar to those of their corresponding host materials. These findings indicate that the crystal structure of the host matrix remains unchanged after doping with trace amounts of guest molecules, demonstrating that a small amount of guest material does not alter the overall stacking pattern.

[0035] Example 12 High-security data encryption: Leveraging the controllable tuning of phosphorescent afterglow lifetime in doped systems, two functional materials, BMB / PBM-CN and BMB / PBM-Br, are applied to time-resolved dynamic cryptography. Specifically, under ultraviolet light excitation ( Figure 11 The optical signal is a "dash-dot-dot-dot" transmission sequence, which is directly converted to the letter "B" by Morse code decoding rules. When the excitation light source is turned off for 1 second, the optical signal at this time is encrypted information, and its transmission sequence is "dash-space-space-space", which is converted to the letter "T", corresponding to the encrypted password. Based on this principle, the time-encrypted signal in Figure 11 is decoded into the letters "R", "U", and "E" respectively, and finally combined to form the complete password "TRUE".

[0036] As can be seen from the above embodiments, the present invention provides a low-doped organic room-temperature phosphorescent material that can emit significant phosphorescence at a low doping level, and has good application prospects in advanced information storage and anti-counterfeiting encryption fields.

Claims

1. The use of phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivatives as guest materials in host-guest doped organic room-temperature phosphorescent materials, wherein the structure of the phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative is shown in Formula I: Formula I in, R is selected from hydrogen, CN, halogen, methyl, methoxy, halogen-substituted methyl, and dimethylamino.

2. The use according to claim 1, characterized in that: The R is selected from hydrogen, CN, Br, methyl, methoxy, trifluoromethyl, and dimethylamino.

3. The use according to claim 1, characterized in that: The host material of the host-guest doped organic room temperature phosphorescent material is selected from at least one of N-methyl-4-bromobenzamide or benzophenone.

4. A low-doped, high-efficiency room-temperature phosphorescent material, characterized in that, The product comprises a host material and a guest material, wherein the host material is selected from at least one of N-methyl-4-bromobenzamide or benzophenone; and the guest material is selected from a phenyl[2-phenyl-1H-benzo[d]imidazol-5-yl]methyl ketone derivative, the structure of which is shown in Formula I. Formula I R is selected from hydrogen, CN, halogen, methyl, methoxy, halogen-substituted methyl, and dimethylamino.

5. The ultra-low doped, high-efficiency room-temperature phosphorescent material according to claim 4, characterized in that, The mass ratio of the main material to the object material is (100-100000):

1.

6. The ultra-low doped, high-efficiency room-temperature phosphorescent material according to claim 5, characterized in that, The mass ratio of the main material to the object material is (1000-10000):

1.

7. The ultra-low doped, high-efficiency room-temperature phosphorescent material according to claim 6, characterized in that, The mass ratio of the main material to the object material is 1000:

1.

8. The ultra-low doped, high-efficiency room-temperature phosphorescent material according to claim 1, characterized in that: The R is selected from hydrogen, CN, Br, methyl, methoxy, trifluoromethyl, and dimethylamino.

9. The method for preparing the ultra-low doped, high-efficiency room-temperature phosphorescent material according to any one of claims 4-8, characterized in that, include: The host material and the guest material are added to an organic solvent, and after grinding and evaporation of the organic solvent, phosphorescent material powder is obtained.

10. The use of the ultra-low doped, high-efficiency room-temperature phosphorescent material according to any one of claims 4-8 for the preparation of data encryption products or information storage products.

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