Boron-atom-doped organic host-guest long-afterglow material with adjustable luminescence color and preparation method and application of boron-atom-doped organic host-guest long-afterglow material

Abstract

The invention belongs to the technical field of doped host-guest long-afterglow materials, and particularly relates to a boron atom doped organic host-guest long-afterglow material with adjustable luminescence color and a preparation method and application thereof. The method comprises the following steps: dissolving guest molecules of an organic long afterglow material in methanol or deionized water to obtain a methanol solution or a deionized water solution of the guest molecules; and adding boric acid host molecules, adding methanol or deionized water or ethanol, heating and stirring to obtain a clear solution, standing at room temperature, and separating out crystal grains or amorphous powder to obtain the boron atom doped organic long afterglow material. A series of luminescent materials are developed by utilizing an organic host-guest doping mechanism, and the material system has the advantages of low cost, low toxicity, easiness in preparation and the like; the organic host-guest doped room temperature phosphorescent system provided by the invention not only optimizes the luminescence performance, but also has adjustable luminescence color, and has potential application in the fields of biological anti-counterfeiting, data encryption, organic light emitting diodes and the like in the future.

Description

Technical Field

[0001] The invention relates to the technical field of doped host-guest long afterglow materials, and in particular to a boron atom-doped organic host-guest long afterglow material with adjustable luminous color, and a preparation method and application thereof. Background Art

[0002] Organic room-temperature phosphorescence (RTP) materials have long afterglow characteristics because they can emit light through the radiative transition of triplet excitons. Compared with fluorescence, RTP has a longer lifetime (generally in the order of milliseconds to seconds), which makes it show broad application prospects in display technology, anti-counterfeiting identification, information storage and encryption, and sensors. Compared with traditional inorganic RTP materials, organic RTP materials have the advantages of strong designability, environmental friendliness, low cost, and easy processing, so they have attracted much attention. In recent years, organic doped system RTP has attracted widespread attention from researchers. However, due to the extreme sensitivity of triplet excitons in the material, achieving efficient and stable RTP faces significant challenges. Under normal circumstances, triplet excitons are easily quenched by molecular motion, non-radiative transitions and oxygen at room temperature, resulting in low phosphorescence efficiency. Therefore, how to overcome these bottlenecks through material design and regulation and develop organic RTP materials with excellent performance, especially adjusting the RTP emission color through different doping guests, has become one of the focuses of research in this field in recent years.

[0003] The color control ability of RTP materials is an important indicator of their optical performance. Compared with fixed-color luminescent materials, RTP materials that can achieve multicolor or color-adjustable have wider application potential in display, anti-counterfeiting, smart sensing and other fields. However, traditional organic materials are extremely challenging to achieve multicolor RTP due to their insufficient structural rigidity, limited intermolecular interactions and high sensitivity of triplet excitons. In recent years, through innovative molecular design and system construction, researchers have proposed a variety of strategies to achieve RTP color control.

[0004] Crystal engineering is a common method to achieve RTP color regulation. By regulating the structure of molecules and their stacking patterns in crystals, the energy difference between molecular orbitals can be effectively adjusted, thereby achieving the regulation of luminescent color. Polymer RTP materials restrict the non-radiative transition path of molecules (such as by increasing the rigidity of molecular stacking), which can significantly enhance the RTP performance of the material, providing another effective way for the color regulation of polymer RTP materials; by designing copolymer systems of different functional monomers, a variety of intermolecular interactions (such as electrostatic effects, hydrogen bonding effects and hydrophobic effects) can be achieved, thereby regulating the energy level distribution of molecules and achieving changes in luminescent color. The host-guest doping strategy is a color regulation method that has been widely studied in recent years. By doping phosphorescent molecules as guests into specific polymers or small molecule hosts, the microenvironment provided by the host material can be used to stabilize triplet excitons, thereby improving RTP performance. Zhou et al. found that doping nitrogen atoms in carbon dots can significantly improve the efficiency of their green afterglow luminescence (Chem. Mater., 2016, 28(22): 8221-8227). Adachi's team developed a pure organic host-guest doping system, achieving room temperature afterglow luminescence for up to 1 hour (Nature, 2017, 550 (7676): 384-387). Lian et al. developed a carbon dot-based RTP material, with an afterglow duration of about 8 seconds and a phosphorescence lifetime of about 1.57 seconds (Adv. Funct. Mater., 2018, 28 (45), 1800791-1800798). In addition, the team of Academician Tang Benzhong proposed an organic LPL luminescence system based on the design principle of an inorganic long-lasting luminescence system, achieving afterglow luminescence for up to 7 hours (J. Electrochem. Soc., 1996, 143 (10): 2670-2673).

[0005] Although RTP doping systems have made significant progress in recent years, there are still some shortcomings. For example, there are relatively few types of RTP materials, especially those doped with organic small molecules, which limits the application scope of this material in different fields. Although studies have achieved color-tunable RTP systems, most of these systems are limited to limited color changes, such as from green to yellow or orange. There is a lack of more organic RTP systems with long lifetimes and adjustable colors, especially red light RTP materials doped with organic small molecules, which limits its application potential in multicolor display, multidimensional information encryption, and bioimaging.

[0006] The present invention further reveals the intrinsic relationship between the organic doping system molecules and the RTP performance from the perspective of molecule selection and doping system construction. In addition, combining the organic RTP material of the present invention with other advanced technologies (such as flexible electronics and bio-intelligent sensing) may bring more inspiration and possibilities to the development of information encryption, health monitoring and environmental monitoring. Summary of the invention

[0007] In view of the fact that the types of color-adjustable organic phosphorescent host-guest system luminescent materials are insufficient and need to be further expanded, the present invention provides an organic host-guest doped RTP system-boron atom organic long afterglow material system with cheap and easy-to-obtain materials, simple preparation method, and long life. The present invention uses a simple host-guest doping strategy to obtain a doping system, and the luminescent color can be adjusted by adjusting the types of guest materials and solvents. The afterglow time is extended or the phosphorescence quantum yield is increased.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows.

[0009] A boron atom-doped organic host-guest long afterglow material with adjustable luminescent color is prepared by mixing boric acid host molecules and organic long afterglow material guest molecules according to a certain molar percentage.

[0010] The guest molecule of the organic long afterglow material is:

[0011]

[0012] The boric acid main molecule is:

[0013]

[0014] Preferably, the boron atoms are doped into the organic long afterglow material, and in terms of molar percentage, the ratio of organic long afterglow material guest molecules to boric acid host molecules is 1:(50-10000).

[0015] A method for preparing a boron atom-doped organic host-guest long afterglow material with adjustable luminescent color comprises the following steps:

[0016] The organic long afterglow material guest molecule is dissolved in methanol or deionized water to obtain a methanol solution or a deionized water solution of the organic long afterglow material guest molecule; the boric acid host molecule is added to the methanol solution or the deionized water solution of the guest molecule, and then methanol or ethanol or deionized water is added, and heated and stirred to obtain a clear and transparent solution; the obtained clear solution is allowed to stand at room temperature to precipitate crystals or amorphous powder, and a boron atom-doped organic host-guest long afterglow material with adjustable luminescent color is obtained.

[0017] Furthermore, the heating temperature is 70-90°C.

[0018] The boron atom-doped organic host-guest long afterglow material with adjustable luminous color provided by the present invention can be used as an anti-counterfeiting material.

[0019] In the boron atom-doped organic host-guest long afterglow material system with adjustable luminescent color described in the present invention, boron atoms easily form covalent bonds with guest molecules, which helps to build a rigid molecular environment. This environment effectively suppresses the non-radiative transition of triplet excitons, thereby significantly enhancing the stability of triplet excitons. This stable exciton state significantly improves the phosphorescent luminescence performance of the material; in addition, it also shows significant advantages in terms of luminescence efficiency and duration.

[0020] Compared with the existing technology, the present invention has the following beneficial effects.

[0021] 1. The boron atom-doped organic host-guest long afterglow material with adjustable luminescent color of the present invention can produce purple fluorescence and orange-yellow fluorescence under room temperature ultraviolet light irradiation, and can produce blue phosphorescence and orange-red phosphorescence when the excitation light source is turned off. The afterglow duration is significantly prolonged by doping with guest small molecules, so that the system has advantages in terms of luminous efficiency and duration, and the longest afterglow time guest is achieved to 6s. The material realizes the change of luminescent color, phosphorescence lifetime and phosphorescence quantum efficiency under room temperature conditions, which not only expands the application scope of organic room temperature phosphorescent materials but also has potential application prospects in anti-counterfeiting applications, biological imaging and photodiodes.

[0022] 2. The boron atom-doped organic host-guest long afterglow material with adjustable luminescent color of the present invention, the organic long afterglow material guest molecule is uniformly dispersed in the boric acid host molecule, heated and stirred, cooled to room temperature, and then evaporated and filtered to obtain an organic RTP material. The material of the present invention does not require rare elements, heavy atoms, has low cost, simple preparation and simple composition, and causes less pollution to the environment, providing new theoretical data information, reference basis and related information for pure organic phosphorescent materials, and also expanding the types and quantity of organic room temperature phosphorescent material systems.

[0023] 3. The boron atom-doped organic long afterglow materials of the present invention are all organic small molecule compounds. By doping different molar percentages of guest molecules into host molecules such as boric acid, the luminescent properties of the phosphorescent material can be changed; and the material is expected to have potential applications in advanced anti-counterfeiting, data encryption, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Figure 2 is the phosphorescence emission spectra of BDBA, RhB and RhB / BDBA in the solid state.

[0025] Figure 2 The photoluminescence spectrum (red line) and phosphorescence spectrum (black line) of RhB / BDBA at room temperature.

[0026] Figure 3 Lifetime decay diagram of RhB / BDBA and BDBA at room temperature.

[0027] Figure 4 is the phosphorescence emission spectrum of BDBA in the solid state (λ ex =270nm) and the excitation spectrum of RhB in the solid state. Figure 5 Digital photos of RhB / BDBA and HAOA / BA under room temperature (room light), 365 nm ultraviolet light irradiation (uv on), and UV light off (uv off); (a, RhB / BDBA, b, HAOA / BA).

[0028] Figure 6 This is the anti-counterfeiting application of the HAOA / BA doping system of Example 1.

[0029] Figure 7 This is the anti-counterfeiting application of the RhB / BDBA doping system of Example 2. DETAILED DESCRIPTION

[0030] The present invention will be further described in detail below in conjunction with implementation examples.

[0031] Example 1.

[0032] 5-aminoorotic acid doped boric acid long afterglow material (HAOA / BA) (deionized water as solvent)

[0033] 1. Materials

[0034] The guest molecule of the organic long afterglow material is 5-aminoorotic acid (HAOA), and the main molecule of boric acid is boric acid (BA). The structural formula is as follows:

[0035]

[0036] (II) The preparation method is as follows:

[0037] Weigh 0.0008 g of HAOA into a round-bottom flask, add 10 mL of deionized water, stir and heat to 80 °C to obtain a clear HAOA deionized water solution;

[0038] To the HAOA deionized water solution, add 1.5412 g BA and 8 mL deionized water, heat to 90°C and maintain for 30 min, add 3 drops of ethanol to obtain a clear, transparent colorless solution, cool to room temperature, let stand, pierce holes and cover with a film to precipitate crystalline HAOA-doped BA long afterglow material (HAOA / BA) (by molar percentage, HAOA guest molecule: BA host molecule = 1:5000) (0.02%).

[0039] Example 2.

[0040] Rhodamine B doped 1,4-phenylenediboronic acid long afterglow material (RhB / BDBA) (methanol as solvent) (I) Materials

[0041] The guest molecule of the organic long afterglow material is rhodamine B (RhB), and the main molecule of boric acid is 1,4-phenylenediboronic acid (BDBA). The structural formula is as follows:

[0042]

[0043] (II) The preparation method is as follows:

[0044] Weigh 0.0095g of RhB into a round-bottom flask, then add 10mL of methanol. Stir and heat to 70°C to obtain a clear methanol solution of RhB. Add 0.1650g of BDBA, heat to 90°C and maintain for 30min to obtain a clear and transparent solution, cool to room temperature, let stand, pierce holes and cover with film to obtain a crystalline RhB-doped BABD long afterglow material (RhB / BDBA) (by molar percentage, RhB guest molecule: BABD host molecule = 1:50) (2%).

[0045] Example 3.

[0046] Rhodamine B doped 4-carboxyphenylboronic acid long afterglow material (RhB / 4-CBBA) (methanol as solvent) (I) Materials

[0047] The guest molecule of the organic long afterglow material is rhodamine B (RhB), and the main molecule of boric acid is 4-carboxyphenylboronic acid (4-CBBA). The structural formula is as follows:

[0048]

[0049] (II) The preparation method is as follows

[0050] Weigh 0.0095g of RhB into a round-bottom flask, then add 10mL of methanol. Stir and heat to 70°C to obtain a clear methanol solution of RhB. Add 0.1650g of 4-CBBA, raise the temperature to 90°C, maintain for 30min, obtain a clear and transparent solution, cool to room temperature, let stand, pierce holes and cover with film to obtain a crystalline RhB-doped 4-CBBA long afterglow material (RhB / 4-CBBA) (by molar percentage, RhB guest molecule: 4-CBBA host molecule = 1:50) (2%).

[0051] Example 4.

[0052] Phthalohydrazide-doped 1,4-phenylenediboric acid long afterglow material (Phth / BDBA) (methanol as solvent) (I) Materials

[0053] The guest molecule of the organic long afterglow material is phthalohydrazide (Phth), and the main molecule of boric acid is 1,4-phenylenediboronic acid (BDBA). The structural formula is as follows:

[0054]

[0055] (II) The preparation method is as follows

[0056] Weigh 0.005g of Phth into a round-bottom flask, then add 10mL of methanol. Stir and heat to 70°C to obtain a clear Phth solution. Add 0.255g of BDBA, heat to 90°C and maintain for 30min to obtain a clear and transparent solution. Cool to room temperature, let stand, pierce holes and cover with film to obtain a crystalline Phth-doped BDBA long afterglow material (Phth / BDBA) (by molar percentage, Phth guest molecule: BDBA host molecule = 1:50) (2%).

[0057] test:

[0058] 1. At room temperature, the phosphorescence emission spectrum of the long afterglow material (RhB / BDBA) obtained by changing the molar percentage of the host and guest by the preparation method of Example 2 was measured; and the phosphorescence emission spectra of RhB and BDBA were measured respectively, as shown in FIG. Figure 1 As shown. a: BDBA solid-state phosphorescence spectrum, b: RhB solid-state phosphorescence spectrum, c: phosphorescence spectra of RhB:BDBA doping system with different ratios.

[0059] 2. At room temperature, the long afterglow material (RhB / BDBA) prepared in Example 2 was used; the photoluminescence spectrum (red line) and phosphorescence spectrum (black line) were measured. Figure 2 shown.

[0060] 3. At room temperature, the long afterglow material (RhB / BDBA) prepared in Example 2 was used to measure the lifetime decay diagrams of RhB / BDBA (red) and BDBA (black), as shown in FIG. Figure 3 shown.

[0061] 4. At room temperature, the long afterglow material (RhB / BDBA) prepared in Example 2; the phosphorescence emission spectrum of BDBA in the solid state (λ ex = 270 nm) (black line) and RhB (red line) in the solid state. Figure 4 shown.

[0062] 5. The organic long afterglow material doped with boron atoms obtained by changing the molar percentage of the host and guest according to the preparation methods of Example 1 (HAOA / BA) and Example 2 (RhB / BDBA) was irradiated with sunlight and 365nm ultraviolet light respectively, and then the ultraviolet light was turned off to detect the change of the long afterglow. The results are as follows: Figure 5 As shown in the figure, it can be seen that under the irradiation of ultraviolet light, HAOA / BA has purple fluorescence and RhB / BDBA has orange fluorescence; after turning off the ultraviolet light, a blue afterglow of HAOA / BA and an orange afterglow of RhB / BDBA can be observed.

[0063] 6. The doped material of Example 1 (HAOA / BA) is prepared into the anti-counterfeiting number "2024", and the doped material of Example 2 (RhB / BDBA) is prepared into a fisherman fishing (RhB is used to make the fisherman and the boat, BDBA is used to make the reeds, and RhB / BDBA is used to make the sun). The two patterns are respectively irradiated under sunlight and under ultraviolet light at 365nm, and then the ultraviolet light is turned off to observe the color change.

[0064] like Figure 6 As shown, under sunlight, the doped material 8888 is white under indoor light; under 365nm ultraviolet light, it exhibits purple fluorescence; after turning off the ultraviolet light for 1 second, a digital pattern of 2024 showing blue phosphorescence can be observed, and 2024 disappears 3 seconds after turning off the ultraviolet light.

[0065] like Figure 7 As shown, under sunlight, various parts of the fisherman fishing with doped materials appear in different colors, the fisherman and the boat are black-brown, the reeds are white, and the sun is pink; under 365nm ultraviolet light, the fisherman and the boat show red fluorescence, the reeds show blue fluorescence, and the sun shows orange-yellow fluorescence; after turning off the ultraviolet light, the sun and the reeds can be seen in 1 second, the sun shows an orange-red afterglow, the reeds show a green afterglow, while the fisherman and the boat have no afterglow, and then the green afterglow of the reeds disappears within 1.5 seconds, while the orange-red afterglow of the sun slowly disappears afterwards.

[0066] Therefore, the present invention can be applied to multiple encryption anti-counterfeiting technology.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A boron atom-doped organic host-guest long afterglow material with adjustable luminescent color, characterized in that: It is prepared by mixing a boric acid main molecule and an organic long afterglow material guest molecule according to a certain molar percentage; The guest molecule of the organic long afterglow material is: The boric acid main molecule is:

2. The boron atom-doped organic host-guest long afterglow material with adjustable luminescent color according to claim 1, characterized in that: According to molar percentage, the ratio of organic long afterglow material guest molecule to boric acid host molecule is 1: (50-10000).

3. The method for preparing the boron atom-doped organic host-guest long afterglow material with adjustable luminescent color according to claim 1 comprises the following steps: The organic long afterglow material guest molecule is dissolved in methanol or deionized water to obtain a methanol solution or a deionized water solution of the organic long afterglow material guest molecule; the boric acid host molecule is added to the methanol solution or the deionized water solution of the guest molecule, and then methanol or ethanol or deionized water is added, and heated and stirred to obtain a clear and transparent solution; the obtained clear solution is allowed to stand at room temperature to precipitate crystals or amorphous powder, and a boron atom-doped organic host-guest long afterglow material with adjustable luminescent color is obtained.

4. The preparation method according to claim 3, characterized in that: The heating temperature is 70-90℃.

5. Use of the boron atom-doped organic host-guest long afterglow material with adjustable luminescent color according to claim 1 or 2 in anti-counterfeiting materials.

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