Flexible crystalline material with afterglow, display material and information conduction material

Abstract

The invention provides a flexible crystal material with afterglow, a display material and an information conduction material. The flexible crystal material with afterglow is a two-component doping system which takes xanthone as a small molecule host material and xanthone derivatives as an organic light-emitting guest material. The micromolecule host material and the organic light-emitting guest material respectively have molecular structures shown in general formulas (I) and (II). The flexible crystal material can be effectively excited by ultraviolet light and visible light, covers a wide excitation range, and has a phosphorescence lifetime of 966.21 ms at room temperature. The utilization rate of triplet excitons is improved by utilizing dual-channel emission, and the flexible crystal material simultaneously shows two characteristics of thermally activated delayed fluorescence and phosphorescence and has a photoluminescence quantum yield of 28.5%. In addition, the elastic modulus and the average hardness of the flexible crystal material are 0.053 MPa and 0.092 MPa respectively, and meanwhile, the flexible crystal material has the bending strain capacity of 2.34%.

Description

Technical Field

[0001] The present invention relates to the technical field of organic light-emitting materials, and particularly to a flexible crystal material with ultra-long afterglow, a preparation method thereof, and applications thereof in optoelectronic devices, display materials, and information conduction materials. Background Art

[0002] Organic long afterglow materials with fascinating properties have received extensive attention. Organic long afterglow materials mainly rely on abundant and stable triplet excitons. At present, crystal engineering and host-guest doping are the main methods for fabricating organic long afterglow materials. Crystal engineering can not only provide rigidity but also effectively regulate the excited state through stacking, thereby finely adjusting the luminescence properties. However, most crystals are prone to fracture when stressed, making them difficult to fabricate and severely limiting their applications in the fields of optoelectronic information transmission and encryption. Although it has been reported that a few flexible crystals have phosphorescent functions, there is a trade-off between the flexibility and persistent phosphorescence of these crystals. In addition, the proportion of flexible crystal materials with time response in the cross-field of optical information conduction and encryption has been increasing year by year. Therefore, constructing flexible crystals with long-lived emission and processing feasibility is attractive and challenging.

[0003] Therefore, if a new type of flexible crystal material with ultra-long afterglow can be developed, it will contribute to expanding the advanced applications of luminescent crystal materials in the fields of optics and materials science. Summary of the Invention

[0004] The purpose of the present invention is to provide a new type of flexible crystal material with ultra-long afterglow, a preparation method thereof, and applications thereof. In the present invention, a xanthene derivative is used as a guest molecule, which is doped with xanthene and a small molecule host of bromoxanthene, and a new type of flexible crystal material with ultra-long afterglow is prepared by slowly volatilizing the solvent at room temperature. Due to the rigid environment provided by the molecular host, the energy transfer between the host and guest, and the synergistic effect of dual-channel emission, while stabilizing and enriching triplet excitons, triplet excitons can be efficiently utilized, and a flexible crystal material with ultra-long afterglow can be obtained. In addition, the elastic modulus and average hardness of the flexible crystal material are 0.053 MPa and 0.092 Mpa respectively, and it also has a bending strain capacity of 2.34%.

[0005] To achieve the above object, the present invention provides a flexible crystal material with afterglow, which comprises a small molecule host material and an organic light-emitting guest material, and the small molecule host material has the structure shown in the following formula (I):

[0006] and

[0007] The organic light-emitting guest material has the structure shown in the following formula (II):

[0008]

[0009] Wherein X is H, Cl, Br or I; A is an alkyl group or a phenyl group; B is an alkyl group or a phenyl group.

[0010] In one embodiment of the present invention, based on the total mass of the flexible crystal material, the content of the organic light-emitting guest material is 0.01% by mass to 50% by mass.

[0011] In one embodiment of the present invention, based on the total mass of the flexible crystal material, the content of the small molecule host material is 50% by mass to 99.99% by mass.

[0012] In one embodiment of the present invention, the flexible crystal material has: a persistent luminescence lifetime ≥ 0.1 ms, a photoluminescence quantum yield ≥ 0.1%, and a delayed emission peak wavelength ≥ 400 nm.

[0013] In one embodiment of the present invention, the flexible crystal material has an excitation wavelength ranging from 250 nm to 500 nm.

[0014] In one embodiment of the present invention, the flexible crystal material has characteristics dependent on the excitation wavelength.

[0015] In one embodiment of the present invention, after the flexible crystal material is irradiated with ultraviolet light or visible light, it exhibits yellow-green persistent luminescence emission.

[0016] In one embodiment of the present invention, the flexible crystal material also has dual-channel emission of thermally activated delayed fluorescence and phosphorescence.

[0017] In one embodiment of the present invention, there is a triplet-triplet energy transfer between the molecules of the small molecule host material and the organic light-emitting guest material.

[0018] In one embodiment of the present invention, the flexible crystal material has temperature responsiveness.

[0019] In one embodiment of the present invention, the temperature responsiveness is between -196 and 150 degrees Celsius.

[0020] In one embodiment of the present invention, the flexible crystal material has a waveguide ability of 0 - 1.0 dBmm in the natural state and the bent state. -1 of the optical waveguide ability.

[0021] To achieve the above object, another embodiment of the present invention provides a preparation method of a flexible crystal material with persistent luminescence, and the preparation method includes the following steps:

[0022] Adding the small molecule host material and the organic light-emitting guest material into a solvent,

[0023] Volatilize slowly at room temperature to obtain the flexible crystal material; wherein, the small molecule host material has the structure shown in the following formula (I):

[0024] and

[0025] The organic light-emitting guest material has the structure shown in the following formula (II):

[0026]

[0027] X is H, Cl, Br or I; A is an alkyl group or a phenyl group; B is an alkyl group or a phenyl group.

[0028] In one embodiment of the present invention, based on the total mass of the flexible crystal material, the content of the organic light-emitting guest material is 0.01% by mass to 50% by mass.

[0029] Another embodiment of the present invention provides an optoelectronic device, and the optoelectronic device includes the flexible crystal material with afterglow as described above.

[0030] Another embodiment of the present invention provides a display material, and the display material includes the flexible crystal material with afterglow as described above.

[0031] Another embodiment of the present invention provides an information conduction material, and the information conduction material includes the flexible crystal material with afterglow as described above

[0032] In the embodiments of the present invention, xanthene derivatives are used as organic light-emitting guests, and small molecules such as xanthene and bromoxanthene are used as doping host materials to prepare a flexible crystal material with afterglow. In the embodiments of the present invention, the raw materials used are all purified organic compounds, which are widely sourced and commercially available. The preparation process is simple, efficient, inexpensive and economical. The flexible crystal material with ultra-long afterglow prepared by the present invention has properties such as triplet-triplet energy transfer and dual-channel emission, and its photophysical properties are efficient and stable. It can be used in air without the protection of inert gas or an absolute vacuum environment. The flexible crystal material with afterglow prepared by the present invention has excellent material properties and ultra-long phosphorescence properties, and can be well applied in optoelectronic devices, display materials, information conduction materials or anti-counterfeiting materials, etc. Description of the Drawings

[0033] Figure 1 It is the steady-state luminescence spectrum and delayed luminescence spectrum of the flexible crystal material H1-G1 with afterglow obtained in one embodiment of the present invention;

[0034] Figure 2 It is the lifetime decay spectrum of the flexible crystal material H1-G1 with afterglow obtained in one embodiment of the present invention;

[0035] Figure 3 It is the delayed emission spectrogram of the temperature response (before and after physical temperature control) of the flexible crystal material with afterglow obtained in Example 1 of the present invention;

[0036] Figure 4 It is the delayed emission spectrogram of the excitation wavelength response (before and after changing the excitation light wavelength) of the flexible crystal material with afterglow obtained in Example 1 of the present invention;

[0037] Figure 5 It is the photoluminescence quantum yield diagram of the flexible crystal material with afterglow obtained in Example 1 of the present invention;

[0038] Figure 6 It is the nanoindentation pressure-displacement relationship diagram of the flexible crystal material with afterglow obtained in Example 1 of the present invention;

[0039] Figure 7 It is the steady-state luminescence spectrum and delayed emission spectrum of the flexible crystal material H1-G2 with afterglow obtained in Example 2 of the present invention;

[0040] Figure 8 It is the lifetime decay spectrogram of the flexible crystal material with afterglow obtained in Example 2 of the present invention;

[0041] Figure 9 It is the delayed emission spectrogram of the temperature response (before and after physical temperature control) of the flexible crystal material with afterglow obtained in Example 2 of the present invention;

[0042] Figure 10 It is the delayed emission spectrogram of the excitation wavelength response (before and after changing the excitation light wavelength) of the flexible crystal material with afterglow obtained in Example 2 of the present invention;

[0043] Figure 11 It is the photoluminescence quantum yield diagram of the flexible crystal material with afterglow obtained in Example 2 of the present invention;

[0044] Figure 12 It is the nanoindentation (pressure-displacement relationship) diagram of the flexible crystal material with afterglow obtained in Example 2 of the present invention;

[0045] Figure 13 It is the photo of the luminescence change of the flexible crystal material with afterglow obtained in Example 1 and Example 2 of the present invention before and after ultraviolet light excitation;

[0046] Figure 14 It is the optical waveguide photo of the novel flexible crystal material with ultra-long afterglow obtained in Example 1 of the present invention in the natural state and bent state under laser irradiation.

[0047] Figures 15a - 15cA multifunctional information transmission and encryption system made of the flexible crystal material with afterglow obtained in Embodiment 3 of the present invention. Detailed implementation manners

[0048] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0049] An embodiment of the present invention provides a flexible crystal material with afterglow. First, a small molecule host material and an organic light-emitting guest material are mixed in a certain proportion into a solvent, and then the flexible crystal material with afterglow is obtained through solvent evaporation at room temperature. The small molecule host has the structure shown in H1 or H2 below:

[0050]

[0051] The organic light-emitting guest material has the structure shown in G1 or G2 below:

[0052]

[0053] Optionally, in some embodiments, based on the total mass of the flexible crystal material with afterglow, the content of the small molecule guest material is 0.01% to 50% by mass. Preferably, the content of the small molecule guest material is 0.5% by mass.

[0054] Optionally, in some embodiments, the afterglow lifetime of the flexible crystal material with afterglow prepared in the present invention is ≥0.1 ms, the photoluminescence quantum yield is ≥0.1%, and the delayed emission peak wavelength is ≥400 nm.

[0055] Optionally, in some embodiments of the present invention, the flexible crystal material with afterglow has an excitation wavelength in the range from ultraviolet light to visible light. Preferably, the excitation wavelength range is 250 nm to 500 nm.

[0056] Optionally, in some embodiments of the present invention, the flexible crystal material with afterglow has a stimulus-responsive property through the excitation wavelength. Preferably, the excitation wavelength range is 250 nm to 500 nm.

[0057] Optionally, in some embodiments, according to different small molecule host materials, the flexible crystal material with afterglow prepared shows a yellow-green afterglow emission after being irradiated with ultraviolet light or visible light. Preferably, the host material is selected as H1.

[0058] Optionally, in some embodiments, depending on the selection of the host, the novel flexible crystal material with ultra-long afterglow prepared by the present invention realizes dual-channel emission of thermally activated delayed fluorescence and phosphorescence. Preferably, the small molecule host material is H1.

[0059] In some embodiments, the flexible crystal material with afterglow has excellent optical waveguide ability of 0 - 1.0 dB mm both in the natural state and the bent state. -1

[0060] In some embodiments, there is triplet-triplet energy transfer between the molecules of the small molecule host material and the organic light-emitting guest material.

[0061] In some embodiments, depending on the temperature range, the flexible crystal material with afterglow of the present invention has temperature responsiveness. Preferably, the temperature range is between -196 and 150 degrees Celsius. The elastic modulus and average hardness of the flexible crystal material are 0.053 MPa and 0.092 Mpa respectively, and it also has a bending strain ability of 2.34%.

[0062] Correspondingly, in one embodiment, a preparation method of a flexible crystal material with afterglow is further provided, including: mixing a small molecule host material and an organic light-emitting guest material into a solvent, and then volatilizing the solvent at room temperature to obtain a flexible crystal material with afterglow.

[0063] Optionally, in the preparation method of the flexible crystal material with afterglow, the solvent is used to dissolve the small molecule host material and the organic light-emitting guest material. Preferably, the solvent is dichloromethane.

[0064] In addition, the present invention also provides applications in optoelectronic devices, display materials, information conduction materials, anti-counterfeiting materials, etc. The optoelectronic devices, display materials, information conduction materials, or anti-counterfeiting materials may include the above flexible crystal material.

[0065] Example 1: Preparation of flexible crystal material H1-G1

[0066] In this embodiment, in the novel flexible crystal material H1-G1 with ultra-long afterglow provided, H1 is the host and G1 is the guest. H1 is directly purchased from a reagent company and is in powder form. The specific steps for preparing the guest material G1 are as follows:

[0067]

[0068] 3-Bromo-9H-xanthen-9-one (200 mg, 0.73 mmol), 4-(triphenylamino)benzeneboronic acid (232 mg, 0.80 mmol), potassium carbonate (5.4 g, 39 mmol) and palladium(0) tetrakis(triphenylphosphine) (50 mg, 0.05 mmol) were added to a solvent mixture of tetrahydrofuran (15 ml) and deionized water (10 ml). The reaction mixture was stirred overnight at 80 °C under a nitrogen atmosphere. After completion of the reaction, the reaction was quenched with water and the product was extracted with dichloromethane. After drying over anhydrous sodium sulfate, filtration and concentration, the crude product was purified by silica gel column chromatography (DCM:PE = 1:1) to obtain 278 mg of the guest material, with a yield of 86.6%.

[0069] After multiple column chromatography and recrystallization purifications of host H1 and guest G1, the specific steps for preparing the novel flexible crystal material H1-G1 with ultralong afterglow are as follows:

[0070] Compound H1 (100 mg) and G1 (1.12 mg, 0.5 mol%) were accurately weighed and placed together in a 20 ml screw-cap vial. After adding 5 ml of dichloromethane solvent, the mixture was sonicated for 20 minutes at 40 °C to disperse it evenly, and then allowed to evaporate naturally at room temperature to obtain the novel flexible crystal material with ultralong afterglow. Its delayed emission spectrum is as Figure 1 shown, with two main emission peaks at emission wavelengths of 480 nm and 540 nm respectively; the lifetime decay curve is as Figure 2 shown, with a phosphorescence lifetime of 966.24 ms and a thermally activated delayed fluorescence lifetime of 564.61 ms; this material has a certain temperature dependence and excitation wavelength dependence, as Figure 3 、 4 shown; in addition, Figure 5 shows that the photoluminescence quantum yield of this material is 28.5%, and it has excellent mechanical properties, as Figure 6 shown. The flexible crystal appears light yellow in the natural state, emits light blue under ultraviolet light irradiation, and shows yellow-green afterglow after turning off the ultraviolet light irradiation. The afterglow images and their optical waveguide images are as Figure 13 、 14 shown.

[0071] Example 2: Preparation of the flexible crystal material H1-G2

[0072] In this example, in the flexible crystal material H1-G2 with afterglow provided, H1 is the host and G2 is the guest. H1 was directly purchased from a reagent company and is in powder form. The specific steps for preparing the guest material G2 are as follows:

[0073]

[0074] 3-Bromo-9H-xanthen-9-one (200 mg, 0.73 mmol), 4-(dimethylamino)phenylboronic acid (150 mg, 0.91 mmol), potassium carbonate (5.4 g, 39 mmol) and tetrakis(triphenylphosphine)palladium (50 mg, 0.05 mmol) were added to a solvent of tetrahydrofuran (15 ml) and deionized water (10 ml). The reaction mixture was stirred overnight at 80 °C under a nitrogen atmosphere. After the reaction was completed, the reactants were quenched with water and extracted with dichloromethane. After drying over anhydrous sodium sulfate, filtering and concentrating, it was purified by silica gel column chromatography (DCM:PE = 2:1) to obtain 231 mg of the guest material molecule, with a yield of 73.3%.

[0075] After the host H1 and the guest G2 were purified by multiple column chromatographies and recrystallizations, the specific steps for preparing the flexible crystal material H1-G2 with afterglow were as follows:

[0076] Compound H1 (100 mg) and G2 (0.80 mg, 0.5 mol%) were accurately weighed and placed together in a 20-ml screw-cap bottle. After adding 5 ml of dichloromethane solvent, it was sonicated at 40 °C for 20 minutes to disperse it evenly, and then naturally volatilized at room temperature to obtain a novel flexible crystal material with ultra-long afterglow. Its delayed emission spectrum was as Figure 7 shown, there was a main emission peak and a lower shoulder peak, and the emission wavelengths were 490 nm and 560 nm respectively; the delayed emission lifetime decay curve was as Figure 8 shown, the phosphorescence lifetime was 265.81 ms, and the thermally activated delayed fluorescence lifetime was 177.12 ms; this material had a certain temperature dependence and excitation wavelength dependence, as Figure 9 , 10 shown; in addition, the photoluminescence quantum yield of this material was 16.2% and it had excellent mechanical properties. The flexible crystal showed a pale yellow color in the natural state, emitted a pale blue light under ultraviolet light irradiation, and showed a yellowish-white afterglow after turning off the ultraviolet light irradiation. The afterglow picture was as Figure 13 shown.

[0077] Example 3: Information Transmission and Encryption Application

[0078] In this example, an application of a multifunctional information transmission and encryption device was provided.

[0079] First, the materials in Examples 1 and 2 and the host molecule H1 were arranged according to different combination queues, and then used as the luminescent photo of the information transmitter ( Figure 15a)。A signal transmitter of Morse code is developed by using different doped crystal materials and host molecules according to their three-dimensional colors and different arrangements. Among them, the signal point of host molecule H1 represents "×", that is, it does not contain Morse code signals. The doped crystals H1-G2 in Example 2 and the doped crystal H1-G1 in Example 1 represent "-" and "·" in Morse code respectively. Under the ultraviolet irradiation at 365 nm, blue light is emitted from other signal points except H1 in the 4x4 array, showing the positions of Morse code signals in the array. When the ultraviolet irradiation is turned off, the material has yellow-green afterglow. However, after 3 s, the afterglow of H1-G2 disappears, and the disappearing position is the position of the "-" signal point. The remaining luminous points are the positions of the "·" signal points. Through the Morse code transmission of the 4×4 array, the Morse codes displayed horizontally and vertically in the array are "UCDF" and "PHOS" respectively. This process only requires moving the position of the container and turning on and off the 365 nm ultraviolet light, making this information transmitter universal and reusable.

[0080] In addition, time-resolved multi-level information encryption is realized by using the flexible crystal material in Example 1 ( Figure 15b ). The equation "8 + 8 = 18" is made by using the materials and the host molecule H1 in Examples 1 and 2. However, due to the differences in material properties, under the ultraviolet irradiation at 365 nm and 3 s after turning off the ultraviolet irradiation, the equation becomes "9 + 9 = 18" and "9 - 5 = 4" successively. Finally, the path of light irradiation can be captured according to the different afterglow intensities after ultraviolet irradiation, realizing light path tracing ( Figure 15c ). After moving the ultraviolet light source, the points irradiated earlier will show weaker afterglow, while the points irradiated later will show stronger afterglow, thus showing the movement path of the 365 nm light source.

[0081] The present invention has been described by the above related embodiments. However, the above embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and equivalent arrangements included in the spirit and scope of the claims are all included in the scope of the present invention.

Claims

1. A flexible crystalline material with afterglow, characterized in that, The flexible crystal material includes a small molecule host material and an organic light-emitting guest material, and the small molecule host material has a structure represented by the following formula (I): and The organic light-emitting guest material has a structure represented by the following formula (II): wherein X is H, Cl, Br or I; A is an alkyl group or a phenyl group; B is an alkyl group or a phenyl group.

2. The flexible crystal material with afterglow according to claim 1, characterized in that, Based on the total mass of the flexible crystal material, the content of the organic light-emitting guest material is 0.01% to 50% by mass, and the content of the small molecule host material is 50% to 99.99% by mass.

3. The flexible crystal material with afterglow according to any one of claims 1 to 2, characterized in that, The flexible crystal material has: a phosphorescence lifetime ≥ 0.1 ms, a photoluminescence quantum yield ≥ 0.1%, and a delayed emission peak wavelength ≥ 400 nm.

4. The flexible crystalline material with afterglow according to any one of claims 1 to 2, characterized in that, The flexible crystal material has the characteristics dependent on the excitation wavelength, and the excitation wavelength ranges from 250 nm to 500 nm.

5. The flexible crystal material with afterglow according to any one of claims 1 to 2, characterized in that, After being irradiated with ultraviolet light or visible light, the flexible crystal material exhibits yellow-green phosphorescence emission, and the flexible crystal material also has dual-channel emission of thermally activated delayed fluorescence and phosphorescence.

6. The two-component long afterglow flexible crystal material according to any one of claims 1 to 2, characterized in that, The flexible crystal material has an optical waveguide ability of 0 - 1.0 dBmm in the natural state and the bent state. -1 ​ 7. The flexible crystalline material with afterglow according to any one of claims 1 to 2, characterized in that, There is a triplet-triplet energy transfer between the molecules of the small molecule host material and the organic light-emitting guest material.

8. The flexible crystalline material with afterglow according to any one of claims 1 to 2, characterized in that, The flexible crystal material has temperature responsiveness, and the temperature responsiveness is between -196 and 150 degrees Celsius to regulate luminescence.

9. A display material, characterized in that, The display material comprises the flexible crystal material with phosphorescence as described in any one of claims 1 to 8.

10. An information conduction material, characterized in that, The information conduction material comprises the flexible crystal material with phosphorescence as described in any one of claims 1 to 8.

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