Indole derivative doped material with host-guest room temperature phosphorescence mutual conversion characteristic, preparation method and encryption application thereof

Abstract

The invention discloses an indole derivative doped material with host-guest room temperature phosphorescence mutual conversion characteristic, a preparation method and encryption application thereof, and belongs to the technical field of organic luminescent materials, the indole derivative doped material comprises a host material and a guest material, and the host material and the guest material are indole derivatives, different types of substituent groups are introduced into an indole skeleton, so that the photophysical properties of the material are effectively regulated and controlled, and a series of functionalized host materials and guest materials are obtained. Furthermore, the host material and the guest material are physically doped to obtain the organic room-temperature phosphorescent material which has macroscopic long afterglow characteristic and can be mutually converted between host room-temperature phosphorescence and guest room-temperature phosphorescence. The organic room temperature phosphorescent material can be used in the fields of information display, time resolution anti-counterfeiting technology, Morse password encryption, information encryption storage microarrays based on ASCII binary coding and the like.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic light-emitting materials, and particularly relates to an indole derivative doped material with host-guest room-temperature phosphorescence mutual conversion characteristics, a preparation method and encrypted application thereof. BACKGROUND

[0002] Organic room-temperature phosphorescence is a special optical phenomenon that can continue to emit light for several seconds or even hours after the external excitation light source is turned off. Due to its long triplet state lifetime, effective avoidance of biological background fluorescence interference and other advantages, organic room-temperature phosphorescence materials have attracted widespread attention in the fields of biological imaging, optoelectronic devices, anti-counterfeiting, information storage and display. Compared with inorganic phosphorescent materials, organic room-temperature phosphorescent materials have low toxicity, low cost, good processability, unique structure, easy modification and good biocompatibility, and have become a research hotspot of new luminescent materials.

[0003] However, the weak spin-orbit coupling and fast non-radiative transition of pure organic materials inhibit the generation and utilization of triplet excitons, greatly limiting the development and application of organic room-temperature phosphorescent materials. At present, in order to realize efficient organic room-temperature phosphorescence, one is to introduce heteroatoms and / or heavy atoms to enhance spin-orbit coupling and promote intersystem crossing between excited singlet and triplet states. The second is to provide a rigid environment or energy transfer through crystal engineering, host-guest doping strategy, etc. to realize phosphorescent emission. Among them, the host-guest doping strategy has the advantages of simple and effective preparation, low cost, rich molecular structure and universality, and has great potential in the development of organic room-temperature phosphorescent materials.

[0004] However, the weak spin-orbit coupling and fast non-radiative transition of pure organic materials inhibit the generation and utilization of triplet excitons, greatly limiting the development and application of organic room-temperature phosphorescent materials. At present, in order to realize efficient organic room-temperature phosphorescence, one is to introduce heteroatoms and / or heavy atoms to enhance spin-orbit coupling and promote intersystem crossing between excited singlet and triplet states. The second is to provide a rigid environment or energy transfer through crystal engineering, host-guest doping strategy, etc. to realize phosphorescent emission. Among them, the host-guest doping strategy has the advantages of simple and effective preparation, low cost, rich molecular structure and universality, and has great potential in the development of organic room-temperature phosphorescent materials.

[0005] Therefore, developing a new doping system capable of realizing the dynamic mutual conversion of host-guest phosphorescence has an urgent need to break through the bottleneck of single phosphorescence color and limited regulation dimension in the prior art, and to promote the practicalization process of organic room-temperature phosphorescent materials. SUMMARY

[0006] In view of the above defects in the prior art, the present application provides an indole derivative doped material with host-guest room temperature phosphorescence mutual conversion characteristics, a preparation method and an encryption application thereof; the indole derivative doped material comprises a host material and a guest material, and both the host material and the guest material are indole derivatives; by introducing an indole skeleton into different types of substituent groups, the photophysical properties of the material are effectively regulated, so that a series of functionalized host materials and guest materials are obtained. Further, by physically doping the above host material and guest material, an organic room temperature phosphorescent material with a long afterglow characteristic visible to the naked eye and a host room temperature phosphorescence and a guest room temperature phosphorescence that can be mutually converted is obtained. The organic room temperature phosphorescent material can be used in the fields of information display, time-resolved anti-counterfeiting technology, Morse code encryption and information encryption storage microarray based on ASCII binary coding.

[0007] The present application is realized by the following technical solutions:

[0008] In a first aspect, the present application provides an indole derivative doped material with host-guest room temperature phosphorescence mutual conversion characteristics, comprising a host material and a guest material; the host material is an indole derivative represented by general formula I, wherein in general formula I, R1 is selected from one of carbon, nitrogen, oxygen, phosphorus, sulfur, selenium, arylamine, heteroarylamine and sulfone group; R2 is selected from one or more of C3-C5 straight chain alkyl, C7-C9 cycloalkyl, cyano, halogen, amino and hydroxyl; 10 C3-C5 straight chain alkyl, C7-C9 cycloalkyl, cyano, halogen, amino and hydroxyl;

[0009]

[0010] The guest material is an indole derivative represented by general formula II, wherein in general formula II, R3 is selected from one of carbon, nitrogen, oxygen, phosphorus, sulfur, selenium, arylamine, heteroarylamine and sulfone group; R4 is selected from one of aromatic hydrocarbon or heterocyclic aromatic hydrocarbon;

[0011]

[0012] The doping ratio of the guest material is 0.0001wt%-50wt% of the mass of the host material.

[0013] Further, the doping ratio of the guest material is 0.005wt%-10wt%.

[0014] Further, the host material is indole (2,3-b) cycloheptene, and the guest material is 1H-benzo[f]indole.

[0015] In a second aspect, the present application further provides a preparation method of an indole derivative doped material with host-guest room temperature phosphorescence mutual conversion characteristics, specifically comprising the following steps:

[0016] Step one: dissolve the host material and the guest material in a good solvent respectively, and prepare host material and guest material solutions with certain concentrations by ultrasonic dissolution;

[0017] Step two: mix the host solution and the guest solution according to a certain mass ratio, and add a poor solvent to obtain a mixed solution;

[0018] Step three: evaporate the mixed solution by heating under vacuum to obtain an indole derivative doped material.

[0019] Further, in step one, the good solvent is dichloromethane, tetrahydrofuran, acetone, toluene, methanol, ethanol or acetonitrile, the ultrasonic time is 10-60 min, the preparation concentration of the host material is 20-100 mg / mL, and the preparation concentration of the guest material is 0.5-10 mg / mL.

[0020] Further, in step one, the good solvent is dichloromethane, the ultrasonic time is 30 min, the preparation concentration of the host material is 30 mg / mL, and the preparation concentration of the guest material is 1 mg / mL.

[0021] Further, in step two, the guest material is incorporated in a proportion of 0.0001-50 wt% of the host material, the poor solvent is n-hexane, petroleum ether or water, and the volume ratio of the poor solvent to the good solvent is 1-20:1.

[0022] Further, in step two, the guest material is incorporated in a proportion of 0.005-10 wt% of the host material, the poor solvent is n-hexane, and the ratio of the poor solvent to the good solvent is (3-5):1.

[0023] Further, in step three, the vacuum degree is 0.1-30 kPa, and the heating temperature is 20-50℃.

[0024] Further, in step three, the vacuum degree is 0.1-5 kPa, and the heating temperature is 25-30℃.

[0025] In a third aspect, the present application also provides an application of the indole derivative doped material with host-guest room-temperature phosphorescence mutual conversion characteristics in encryption, which specifically includes:

[0026] The phosphorescence emission color is dynamically converted between orange and green by regulating the host-guest doping ratio;

[0027] A time-resolved anti-counterfeiting system is constructed by utilizing the adjustability of the phosphorescence lifetime in the range of 18.79-472 ms;

[0028] An information encryption storage microarray is constructed based on ASCII binary coding.

[0029] Compared with the prior art, the present application has the following advantages:

[0030] 1. The organic room temperature phosphorescent material provided by the present application is an indole derivative, and long-life room temperature phosphorescent emission is successfully achieved according to the actual introduction of different side chain groups and different doping elements and proportions, thereby overcoming the problem of low utilization rate of triplet excitons of pure organic materials;

[0031] 2. The present application first realizes the mutual conversion of host room temperature phosphorescence and guest room temperature phosphorescence, and the phosphorescent emission of the doped system can be mutually converted between host phosphorescence and guest phosphorescence by adjusting the mass ratio of the host and the guest, thereby breaking through the limitation of the existing host-guest system that only shows single guest phosphorescence;

[0032] 3. The organic room temperature phosphorescent material provided by the present application has phosphorescent performance adjustment characteristics, and the phosphorescent lifetime, luminous color and luminous intensity of the organic room temperature phosphorescent material prepared by different mass ratios of host material and guest material can be dynamically adjusted; the phosphorescent lifetime can be adjusted in a wide range of 18.79 to 472 ms, and the luminous color realizes phosphorescent emission including orange and green;

[0033] 4. The organic room temperature phosphorescent material provided by the present application has long afterglow emission visible to the naked eye at room temperature, and can realize long-life, multi-color phosphorescent color, and has good application prospects in the fields of information display, time-resolved anti-counterfeiting technology, Morse code encryption and information encryption storage microarray based on ASCII binary coding. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn according to the actual scale.

[0035] Figure 1 Room temperature phosphorescent spectra of pure host, pure guest, P1 provided for Example 1 of the present application (a), and normalized room temperature phosphorescent spectra of P1 with different doping mass ratios (b);

[0036] Figure 2 Room temperature phosphorescent lifetime spectrum of P1 provided for Example 1 of the present application (a), and phosphorescent photos of P1 under 365 nm ultraviolet light excitation with different doping mass fractions (b);

[0037] Figure 3 Room temperature phosphorescent spectra of pure host, pure guest, P2 provided for Comparative Example 1 of the present application (a), and normalized room temperature phosphorescent spectra of P2 with different doping mass ratios (b);

[0038] Figure 4 Room temperature phosphorescence lifetime spectrum (a) of P2 provided for the present application comparative example 1, and phosphorescence photos (b) of P2 with different doping mass fractions under 365 nm ultraviolet light excitation;

[0039] Figure 5 Room temperature phosphorescence spectrum (a) of pure host, pure guest, P3 provided for the present application comparative example 2, and normalized room temperature phosphorescence spectrum (b) of P3 with different doping mass fractions;

[0040] Figure 6 Room temperature phosphorescence lifetime spectrum (a) of P3 provided for the present application comparative example 2, and phosphorescence photos (b) of P3 with different doping mass fractions under 365 nm ultraviolet light excitation;

[0041] Figure 7 Room temperature phosphorescence spectrum (a) of pure host, pure guest, P4 provided for the present application comparative example 3, and normalized room temperature phosphorescence spectrum (b) of P4 with different doping mass fractions;

[0042] Figure 8 Room temperature phosphorescence lifetime spectrum (a) of P4 provided for the present application comparative example 3, and phosphorescence photos (b) of P4 with different doping mass fractions under 365 nm ultraviolet light excitation;

[0043] Figure 9 Room temperature phosphorescence spectrum (a) of pure host, pure guest, P5 provided for the present application comparative example 4, and normalized room temperature phosphorescence spectrum (b) of P5 with different doping mass fractions;

[0044] Figure 10 Room temperature phosphorescence lifetime spectrum (a) of P5 provided for the present application comparative example 4, and phosphorescence photos (b) of P5 with different doping mass fractions under 365 nm ultraviolet light excitation;

[0045] Figure 11 Application demonstration of the organic room temperature phosphorescent material provided for the present application application example in the field of information display;

[0046] Figure 12 Application demonstration of the organic room temperature phosphorescent material provided for the present application application example in the field of time-resolved anti-counterfeiting technology;

[0047] Figure 13 Application demonstration of the organic room temperature phosphorescent material provided for the present application application example in the field of Morse code encryption;

[0048] Figure 14 Application demonstration of the organic room temperature phosphorescent material provided for the present application application example in the field of information encryption storage microarray based on ASCII binary coding. DETAILED DESCRIPTION

[0049] In order to clearly and completely describe the technical solution and specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings:

[0050] The present invention provides an indole derivative doping material with host-guest room temperature phosphorescence interconversion characteristics, comprising a host material and a guest material, wherein the doping ratio of the guest material is 0.0001wt%-50wt% of the mass of the host material;

[0051] The main material is an indole derivative shown in general formula I,

[0052]

[0053] Wherein, in the general formula I, R1 is selected from one of carbon, nitrogen, oxygen, sulfur, aromatic amine, heteroaromatic amine, and sulfone; the structural formula of the aromatic amine or heteroaromatic amine is any one of III-1 to III-6:

[0054]

[0055] Wherein, X is any one of hydrogen, fluorine, chlorine, bromine and iodine.

[0056] R2 is selected from one or more of hydrogen, methyl, ethyl, propyl, n-butyl, methoxy, ethoxy, cyano, halogen, amino, hydroxyl, and C3-C8 cycloalkyl; the structural formula of C3-C8 cycloalkyl is any one of IV-1 to IV-6:

[0057]

[0058] The guest material is an indole derivative represented by general formula II,

[0059]

[0060] Wherein, in the general formula II, R3 is selected from one of carbon, nitrogen, oxygen, sulfur, aromatic amine, heteroaromatic amine, and sulfone; the structural formula of aromatic amine or heteroaromatic amine is any one of III-1-III-6. R4 is selected from hydrogen and the following Figure V-1 -One of the aromatic hydrocarbons or heterocyclic aromatic hydrocarbons represented by V-3.

[0061]

[0062] Wherein, X is any one of hydrogen and nitrogen.

[0063] When general formula I is used as the main material: R1 is selected from nitrogen, and R2 is selected from any one or more of hydrogen, methyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl (i.e. IV-3-IV-6).

[0064] When the general formula I is used as the host material, in order to realize mutual conversion of the host phosphor and the guest phosphor, R1 is selected from nitrogen, and R2 is selected from cycloheptyl.

[0065] When the general formula II is used as the guest material, R3 is selected from nitrogen, and R4 is selected from formula V-1, wherein X is hydrogen.

[0066] Embodiment 1

[0067] The embodiment provides an indole derivative doped material with host-guest room-temperature phosphor mutual conversion characteristics, which comprises a host material and a guest material; the host material of the embodiment is indole (2,3-b) cycloheptene, and the guest material is 1H-benzo[f]indole; the host material and the guest material in the embodiment can be obtained on the market, and thus the preparation steps are not described herein again. For convenience of description, the doped organic room-temperature phosphor material in the embodiment is denoted as P1.

[0068] The embodiment further provides a preparation method of an indole derivative doped material with host-guest room-temperature phosphor mutual conversion characteristics, which specifically comprises the following steps:

[0069] (1) The host material indole (2,3-b) cycloheptene 90 mg is placed in a sample bottle, 3 mL of dichloromethane is added into the sample bottle, and the host material is fully dissolved by ultrasonic treatment for 30 min to prepare a host material solution with a concentration of 30 mg / mL. The guest material 1H-benzo[f]indole 16 mg is placed in a sample bottle, 16 mL of dichloromethane is added into the sample bottle, and the guest material is fully dissolved by ultrasonic treatment for 30 min to prepare a guest material solution with a concentration of 1 mg / mL.

[0070] (2) The host material solution and the guest material solution are mixed, wherein the guest material is incorporated in the host material at proportions of 0.005 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt% and 10 wt% respectively, and the two are fully mixed by ultrasonic treatment for 30 min; then, n-hexane is added into the mixed solution, and the volume ratio of n-hexane to dichloromethane is 4:1.

[0071] (3) The mixed solution of the host material and the guest material is evaporated to obtain an organic room-temperature phosphor material with uniform doping of the host material and the guest material, under the condition of 1 kPa vacuum and at 25 DEG C.

[0072] The phosphor performance of the pure host material, the pure guest material and the organic room-temperature phosphor material with uniform doping is characterized, and the room-temperature phosphor spectra of the pure host, the pure guest and P1, and the normalized room-temperature phosphor spectra of P1 with different doping mass ratios are obtained. Figure 1 The phosphor performance of the pure host material, the pure guest material and the organic room-temperature phosphor material with uniform doping is characterized, and the room-temperature phosphor spectra of the pure host, the pure guest and P1, and the normalized room-temperature phosphor spectra of P1 with different doping mass ratios are obtained. Figure 2The room temperature phosphorescence lifetime spectrum of P1, and the phosphorescence photos of P1 with different doping mass fractions under 365 nm ultraviolet light excitation. As can be seen from the data, the pure host and the pure guest have no phosphorescence emission at room temperature, but after doping, obvious phosphorescence emission is achieved, and the phosphorescence emission peaks are located at 528, 566, and 619 nm. Among them, the phosphorescence peak at 528 nm corresponds to the phosphorescence emission of the host, and the phosphorescence peaks at 566 and 619 nm correspond to the phosphorescence emission of the guest. It can be clearly seen from the normalized spectrum that the room temperature phosphorescence of the host and the room temperature phosphorescence of the guest can be converted into each other, which depends on the doping proportion of the guest material. The emission of P1 with different doping mass fractions realizes the phosphorescence conversion process from orange to green, which corresponds to the mutual conversion process of the room temperature phosphorescence of the host and the room temperature phosphorescence of the guest. Moreover, the phosphorescence intensity and the emission time of the afterglow visible to the naked eye will change obviously with the change of the doping proportion of the guest, and the phosphorescence lifetime is 18.79 ms-108.38 ms. This special phosphorescence emission behavior is mainly due to the small triplet energy level difference (0.33 eV) between the host and the guest, which makes the triplet-triplet energy transfer and the reverse triplet-triplet energy transfer can exist in the doped system at the same time. Specifically, after excitation, the triplet exciton generated by the host material is transferred to the triplet state of the guest material through the triplet-triplet energy transfer process. At the same time, due to the small triplet energy level difference, the triplet exciton can return to the triplet state of the host material through the reverse triplet-triplet energy transfer process, thereby realizing the mutual conversion of the room temperature phosphorescence of the host and the room temperature phosphorescence of the guest.

[0073] Comparative Example 1

[0074] The present comparative example provides an organic room temperature phosphorescent material of an indole derivative host-guest doped material, which comprises a host material and a guest material. Among them, the host material of the present comparative example is indole, and the guest material is 1H-benzo[f]indole. Both the host material and the guest material in the present comparative example can be obtained by market purchase, so the preparation steps are not described again. For convenience of description, the doped organic room temperature phosphorescent material of the present comparative example is denoted as P2.

[0075] The present comparative example provides a preparation method of an organic room temperature phosphorescent material of an indole derivative host-guest doped material, and the specific steps are as follows:

[0076] (1) Put 90 mg of the host material indole into a sample bottle, add 3 mL of dichloromethane thereto, and ultrasonic for 30 min to make it fully dissolved completely, to configure a 30 mg / mL host material solution. Put 16 mg of the guest material 1H-benzo[f]indole into a sample bottle, add 16 mL of dichloromethane thereto, and ultrasonic for 30 min to make it fully dissolved completely, to configure a 1 mg / mL guest material solution.

[0077] (2) The host material solution and the guest material solution were mixed, wherein the guest material was incorporated at a ratio of 0.005 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, and 10 wt% of the host material. Ultrasonication was performed for 30 minutes to thoroughly mix the two. Then, n-hexane was added to the mixed solution, wherein the volume ratio of n-hexane to dichloromethane was 4:1.

[0078] (3) Slowly evaporate the solvent from the mixed solution of the host material and the guest material at 25°C to 30°C under a vacuum state of 0.1kPa to 5kPa to obtain an organic room temperature phosphorescent material in which the host material and the guest material are uniformly doped.

[0079] The phosphorescence properties of the above pure host material, pure guest material and uniformly doped organic room temperature phosphorescent material were characterized to obtain the following Figure 3 The room temperature phosphorescence spectra of the pure host, pure guest, P2, and the normalized room temperature phosphorescence spectra of P2 with different doping mass ratios are obtained. Figure 4 The room temperature phosphorescence lifetime spectrum of the described P2, and the phosphorescence photos of P2 with different doping mass fractions under 365nm ultraviolet excitation. As can be seen from the data, the pure host and pure guest have no phosphorescence emission at room temperature, but after doping, obvious phosphorescence emission is achieved, and the phosphorescence emission peaks are located at 566 and 619nm. The phosphorescence peaks of 566 and 619nm correspond to the phosphorescence emission of the guest. It can be clearly seen from the normalized spectrum that this comparative example only has guest room temperature phosphorescence emission. P2 with different doping mass fractions only emits orange phosphorescence, and the phosphorescence intensity and the visible afterglow emission time will change significantly with the change of the guest doping ratio, and the phosphorescence lifetime is 421ms-472ms. The difference in this emission behavior is mainly attributed to the larger triplet energy level difference (0.68eV) between the host and the guest in this comparative example, which makes only triplet-triplet energy transfer exist in the doped system, while reverse triplet-triplet energy transfer does not occur in this system, resulting in the doped system only emitting guest phosphorescence. Specifically, after being excited, the triplet excitons generated in the host material are transferred to the triplet state of the guest material through a triplet-triplet energy transfer process, and then return to the ground state through a subsequent radiative transition process.

[0080] Comparative Example 2

[0081] This comparative example provides an organic room-temperature phosphorescent material comprising an indole derivative host-guest dopant, comprising a host material and a guest material. The host material in this comparative example is 2,3-dimethylindole, and the guest material is 1H-benz[f]indole. Both the host and guest materials in this comparative example are commercially available, so their preparation steps are not detailed here. For ease of presentation, the doped organic room-temperature phosphorescent material in this comparative example is designated P3.

[0082] The present comparative example provides a preparation method of an organic room-temperature phosphorescent material of an indole derivative host-guest doped material, and the specific process is as follows:

[0083] (1) Put the host material 2,3-dimethylindole 90 mg into a sample bottle, add 3 mL of dichloromethane thereto, and ultrasonically dissolve it for 30 min to prepare a 30 mg / mL host material solution. Put the guest material 1H-benzo[f]indole 16 mg into a sample bottle, add 16 mL of dichloromethane thereto, and ultrasonically dissolve it for 30 min to prepare a 1 mg / mL guest material solution.

[0084] (2) Mix the host material solution and the guest material solution, wherein the guest material is incorporated at a ratio of 0.005 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, and 10 wt% of the host material. Ultrasonically mix them for 30 min to make them fully mixed and uniform. Then add n-hexane to the mixed solution, wherein the volume ratio of n-hexane to dichloromethane is 4:1.

[0085] (3) Slowly evaporate the solvent of the mixed solution of the host material and the guest material at 0.1 kPa-5 kPa under vacuum at 25-30°C to obtain an organic room-temperature phosphorescent material in which the host material and the guest material are uniformly doped.

[0086] The phosphorescent performance of the pure host material, the pure guest material, and the organic room-temperature phosphorescent material in which the host material and the guest material are uniformly doped is characterized, and the room-temperature phosphorescent spectra of the pure host, the pure guest, and P3, and the normalized room-temperature phosphorescent spectra of P3 with different doping mass ratios are obtained as follows: Figure 5 Figure 6 ​The room temperature phosphorescence lifetime spectrum of P3, and the phosphorescence photos of P3 with different doping mass fractions under 365 nm ultraviolet light excitation. As can be seen from the data, the pure host and the pure guest have no phosphorescence emission at room temperature, but after doping, obvious phosphorescence emission is realized, and the phosphorescence emission peaks are located at 566 nm and 619 nm. The phosphorescence peaks at 566 nm and 619 nm correspond to the phosphorescence emission of the guest. It can be clearly seen from the normalized spectrum that the host-guest system only has the guest room temperature phosphorescence emission. P3 with different doping mass fractions only emits orange phosphorescence, and the phosphorescence intensity and the emission time of the afterglow visible to the naked eye will change obviously with the change of the guest doping ratio, and the phosphorescence lifetime is 247 ms-372 ms. The difference in emission behavior is mainly due to the large triplet energy level difference (0.63 eV) between the host and the guest in the comparative example, so that only triplet-triplet energy transfer exists in the doped system, and the reverse triplet-triplet energy transfer does not occur in the system, thereby causing the doped system to only emit guest phosphorescence. Specifically, after excitation, the triplet excitons generated by the host material are transferred to the triplet state of the guest material through the triplet-triplet energy transfer process, and then return to the ground state through the subsequent radiative transition process.

[0087] Comparative Example 3

[0088] The comparative example provides an organic room temperature phosphorescent material of an indole derivative host-guest doped material, which comprises a host material and a guest material. The host material of the comparative example is 1,2,3,4-tetrahydrocyclopenta[b]indole, and the guest material is 1H-benzo[f]indole. The host material and the guest material in the comparative example can be obtained from the market, so the preparation steps are not described again. For convenience of description, the organic room temperature phosphorescent material doped by the comparative example is denoted as P4.

[0089] The comparative example provides a preparation method of an organic room temperature phosphorescent material of an indole derivative host-guest doped material, and the specific process is as follows:

[0090] (1) Put 90 mg of the host material 1,2,3,4-tetrahydrocyclopenta[b]indole into a sample bottle, add 3 mL of dichloromethane thereto, and ultrasonic for 30 min to make it fully dissolved and complete, to configure a 30 mg / mL host material solution. Put 16 mg of the guest material 1H-benzo[f]indole into a sample bottle, add 16 mL of dichloromethane thereto, and ultrasonic for 30 min to make it fully dissolved and complete, to configure a 1 mg / mL guest material solution.

[0091] (2) The host material solution and the guest material solution were mixed, wherein the guest material was incorporated at a ratio of 0.005 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, and 10 wt% of the host material. Ultrasonication was performed for 30 minutes to thoroughly mix the two. Then, n-hexane was added to the mixed solution, wherein the volume ratio of n-hexane to dichloromethane was 4:1.

[0092] (3) Slowly evaporate the solvent from the mixed solution of the host material and the guest material at 25°C to 30°C under a vacuum state of 0.1kPa to 5kPa to obtain an organic room temperature phosphorescent material in which the host material and the guest material are uniformly doped.

[0093] The phosphorescence properties of the pure host material, pure guest material and uniformly doped organic room temperature phosphorescent material were further characterized to obtain the following Figure 7 The room temperature phosphorescence spectra of the pure host, pure guest, P4, and the normalized room temperature phosphorescence spectra of P4 with different doping mass ratios are obtained. Figure 8 The room temperature phosphorescence lifetime spectrum of the described P4, and the phosphorescence photos of P4 with different doping mass fractions under 365nm ultraviolet excitation. As can be seen from the data, the pure host and pure guest have no phosphorescence emission at room temperature, but after doping, obvious phosphorescence emission is achieved, and the phosphorescence emission peaks are located at 566 and 619nm. The phosphorescence peaks of 566 and 619nm correspond to the phosphorescence emission of the guest. It can be clearly seen from the normalized spectrum that this comparative example only has guest room temperature phosphorescence emission. P4 with different doping mass fractions only emits orange phosphorescence, and the phosphorescence intensity and the visible afterglow emission time will change significantly with the change of the guest doping ratio, and the phosphorescence lifetime is 183ms-420ms. The difference in this emission behavior is mainly attributed to the larger triplet energy level difference (0.48eV) between the host and the guest in this comparative example, which makes only triplet-triplet energy transfer exist in the doped system, while reverse triplet-triplet energy transfer does not occur in this system, thereby causing the doped system to only emit guest phosphorescence. Specifically, after being excited, the triplet excitons generated in the host material are transferred to the triplet state of the guest material through a triplet-triplet energy transfer process, and then return to the ground state through a subsequent radiative transition process.

[0094] Comparative Example 4

[0095] This comparative example provides an organic room-temperature phosphorescent material comprising an indole derivative host-guest dopant, comprising a host material and a guest material. The host material in this comparative example is 2,3-butylindole, and the guest material is 1H-benz[f]indole. Both the host and guest materials in this comparative example are commercially available, so their preparation steps are not detailed here. For ease of presentation, the doped organic room-temperature phosphorescent material in this comparative example is designated P5.

[0096] The present comparative example provides a preparation method of an organic room-temperature phosphorescent material of an indole derivative host-guest doped material, and the specific process is as follows:

[0097] (1) Put the host material 2,3-extended butyl indole 90 mg into a sample bottle, add 3 mL of dichloromethane thereto, and ultrasonically dissolve it for 30 min to prepare a 30 mg / mL host material solution. Put the guest material 1H-benzo[f]indole 16 mg into a sample bottle, add 16 mL of dichloromethane thereto, and ultrasonically dissolve it for 30 min to prepare a 1 mg / mL guest material solution.

[0098] (2) Mix the host material solution and the guest material solution, wherein the guest material is doped at a ratio of 0.005 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 5 wt%, and 10 wt% of the host material. Ultrasonically mix them for 30 min to make them fully mixed and uniform. Then add n-hexane to the mixed solution, wherein the volume ratio of n-hexane to dichloromethane is 4:1.

[0099] (3) Slowly evaporate the solvent of the mixed solution of the host material and the guest material at 0.1 kPa-5 kPa under vacuum at 25-30°C to obtain an organic room-temperature phosphorescent material with uniform doping of the host material and the guest material.

[0100] The phosphorescent performance of the pure host material, the pure guest material, and the organic room-temperature phosphorescent material with uniform doping is characterized, and the room-temperature phosphorescent spectrum of the pure host, the pure guest, and P5 is obtained as shown in FIG. 1. Figure 9 The room-temperature phosphorescent spectrum of P5 with different doping mass ratios is normalized, and the normalized room-temperature phosphorescent spectrum is obtained as shown in FIG. 2. Figure 10The room temperature phosphorescence lifetime spectrum of P5, and the phosphorescence photos of P5 with different doping mass fractions under 365 nm ultraviolet light excitation. From the data, it can be seen that the pure host and the pure guest have no phosphorescence emission at room temperature, but after doping, obvious phosphorescence emission is realized, and the phosphorescence emission peaks are located at 566 nm and 619 nm. The phosphorescence peaks at 566 nm and 619 nm correspond to the phosphorescence emission of the guest. It can be clearly seen from the normalized spectrum that only the guest room temperature phosphorescence emission exists in the pair of examples. P5 with different doping mass fractions only emits orange phosphorescence, and the phosphorescence intensity and the emission time of the afterimage visible to the naked eye will change obviously with the change of the guest doping ratio, and the phosphorescence lifetime is 396 ms-445 ms. The difference in the emission behavior is mainly due to the large triplet energy level difference (0.44 eV) between the host and the guest in the pair of examples, so that only triplet-triplet energy transfer exists in the doped system, and the reverse triplet-triplet energy transfer does not occur in the system, thereby causing the doped system to only emit guest phosphorescence. Specifically, after excitation, the triplet exciton generated by the host material is transferred to the triplet state of the guest material through the triplet-triplet energy transfer process, and then returns to the ground state through the subsequent radiative transition process.

[0101] Example 2

[0102] As shown in Figure 11 , it is an application demonstration of the organic room temperature phosphorescent material provided by the present embodiment in the information display field. The organic room temperature phosphorescent material obtained by using the organic room temperature phosphorescent material provided by the present embodiment 1 has a long lifetime phosphorescence characteristic. The organic room temperature phosphorescent material is prepared into various different letters or patterns by a hollow template assisted method. After being prepared into "H", "N", "U", and apple, butterfly, star, arrow, etc. patterns by the hollow template assisted method, the patterns show obvious purple, orange or green light emission information before and after 365 nm ultraviolet light excitation.

[0103] As shown in Figure 12 , it is an application demonstration of the organic room temperature phosphorescent material provided by the present embodiment in the time resolution anti-counterfeiting technology field. By using the phosphorescence characteristics of different organic room temperature phosphorescent materials under different time resolutions, a spatiotemporal resolution "star and moon" encryption pattern is designed. Under ultraviolet excitation, a bright purple fluorescent pattern is immediately displayed. However, after the ultraviolet light source is removed, the color of the pattern will immediately change, the moon is orange, and the star is green. With the passage of time, the phosphorescence emission behavior gradually disappears in space and time, and a distinguishable spatiotemporal phosphorescence pattern can be observed, thereby realizing high level anti-counterfeiting.

[0104] As shown in Figure 13The figure shows a demonstration of the application of the organic room temperature phosphorescent material provided in this embodiment in the field of Morse code encryption. The organic room temperature phosphorescent material was assembled into a Morse code code to demonstrate encryption and decryption. Under room temperature ultraviolet light, the entire encrypted signal exhibited purple fluorescence. However, due to interference from background fluorescence signals, valid information could not be obtained. Only when the ultraviolet excitation was turned off did the actual transmitted information appear through an afterglow. Subsequently, by decrypting the information with the Morse code translation, the true message "LOVE" and "PEACE" were finally obtained.

[0105] like Figure 14 As shown, the application of the organic room temperature phosphorescent material provided in this embodiment in the field of information encryption storage microarray based on ASCII binary coding is demonstrated. The organic room temperature phosphorescent material is assembled into a data storage microarray based on the standard 8-bit ASCII character binary code. Among them, the one with obvious phosphorescence emission represents "1", and the one without obvious phosphorescence emission represents "0". Under ultraviolet irradiation, all information points show purple fluorescent signals, which can be converted into invalid information according to the ASCII binary code. However, after turning off the ultraviolet irradiation, the original information displayed by the dot matrix can be easily read and converted into "01001000", "01001110", "01010101", and decoded according to the binary code of the ASCII characters, corresponding to the uppercase letters "H", "N", and "U".

[0106] In summary, the organic room temperature phosphorescent material described herein comprises a host material and a guest material, both of which are indole derivatives. The resulting organic room temperature phosphorescent material exhibits long-lasting emission visible to the naked eye, and the host and guest room temperature phosphorescences can be converted into each other. The organic room temperature phosphorescent material can be used in fields such as information display, time-resolved anti-counterfeiting technology, Morse code encryption, and information encryption storage microarrays based on ASCII binary encoding.

[0107] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0108] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0109] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. An indole derivative doping material having host-guest room temperature phosphorescence interconversion properties, characterized in that: The invention comprises a host material and a guest material; the host material is an indole derivative represented by the general formula I, wherein in the general formula I, R1 is selected from one of carbon, nitrogen, oxygen, phosphorus, sulfur, selenium, aromatic amine, heteroaromatic amine, and sulfone; R2 is selected from one of C3-C5 straight chain alkyl, C7-C 10 One or more of cycloalkyl, cyano, halogen, amino, and hydroxyl; The guest material is an indole derivative represented by general formula II, wherein in general formula II, R3 is selected from one of carbon, nitrogen, oxygen, phosphorus, sulfur, selenium, aromatic amine, heteroaromatic amine, and sulfone; R4 is selected from one of aromatic hydrocarbons or heterocyclic aromatic hydrocarbons; The doping ratio of the guest material is 0.0001 wt%-50 wt% of the host material.

2. The indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, characterized in that: The doping ratio of the guest material is 0.005 wt%-10 wt%.

3. The indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, characterized in that: The host material is indole (2,3-b) cycloheptene, and the guest material is 1H-benz[f]indole.

4. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: The specific steps include: Step 1: Dissolve the host material and the guest material in a good solvent respectively, and dissolve them by ultrasonication to prepare a host material and guest material solution with a certain concentration; Step 2: mixing the host solution and the guest solution in a certain mass ratio, adding a poor solvent to obtain a mixed solution; Step 3: heating and evaporating the mixed solution under vacuum to obtain an indole derivative doping material.

5. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: In step 1, the good solvent is dichloromethane, tetrahydrofuran, acetone, toluene, methanol, ethanol or acetonitrile, the ultrasonic time is 10 min-60 min, the preparation concentration of the host material is 20 mg / mL-100 mg / mL, and the preparation concentration of the guest material is 0.5 mg / mL-10 mg / mL.

6. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: In step 1, the good solvent is dichloromethane, the ultrasonic time is 30 min, the concentration of the host material is 30 mg / mL, and the concentration of the guest material is 1 mg / mL.

7. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: In step 2, the guest material is added in a ratio of 0.0001 wt% to 50 wt% of the host material, the poor solvent is n-hexane, petroleum ether or water, and the volume ratio of the poor solvent to the good solvent is 1-20:

1.

8. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: In step 3, the vacuum degree is 0.1–30 kPa and the heating temperature is 20–50°C.

9. The method for preparing an indole derivative doping material having host-guest room temperature phosphorescence interconversion properties according to claim 1, wherein: In step 2, the guest material is added in an amount of 0.005 wt% to 10 wt% of the host material, the poor solvent is n-hexane, and the ratio of the poor solvent to the good solvent is (3-5):1; In step 3, the vacuum degree is 0.1–5 kPa and the heating temperature is 25–30°C.

10. Application of the indole derivative doping material having host-guest room temperature phosphorescence interconversion properties in encryption as claimed in claim 1, characterized in that: Specifically include: By adjusting the host-guest doping ratio, the phosphorescence emission color can be dynamically switched between orange and green. A time-resolved anti-counterfeiting system was constructed using the tunability of the phosphorescence lifetime in the range of 18.79–472 ms. Construct an information encryption storage microarray based on ASCII binary encoding.

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