Preparation method and application of long afterglow material based on dibenzothiophene molecules

Abstract

The invention discloses a preparation method and application of a long-afterglow material based on dibenzothiophene molecules, and provides an organic long-afterglow material of four aromatic phosphine oxide modified dibenzothiophene, which uses aromatic phosphine oxide groups to modify the dibenzothiophene molecules, so that the rigidity of the molecules is improved, the non-radiative transition of the molecules is inhibited, and the energy loss is reduced. The invention relates to the technical field of organic long-afterglow materials. According to the preparation method and application of the long-afterglow material based on the dibenzothiophene molecules, the afterglow life of the material is adjusted by regulating and controlling the position and number of aromatic phosphorus-oxygen groups, meanwhile, the material with the afterglow property is used as a receptor, donor molecules with excellent properties are selected, and the long-afterglow material based on the dibenzothiophene molecules is obtained through charge transfer among the molecules. The service life performance of the organic long-afterglow material is effectively improved, and the organic long-afterglow material has good luminescence service life and quantum efficiency.

Description

Technical Field

[0001] The invention relates to the technical field of organic long afterglow materials, in particular to a preparation method and application of a long afterglow material based on dibenzothiophene molecules. Background Art

[0002] Organic long persistent luminescence (OLPL) is a phenomenon in which organic materials can continue to emit light after the excitation light fades. Compared with non-organic long persistent fluorescent materials, the use of organic small molecules does not require high forging temperatures, not to mention the doping of rare metal elements, which to a certain extent reduces the manufacturing difficulty and cost, and has aroused great interest.

[0003] With the continuous development of long afterglow materials, in order to achieve OLPL emission and improve the utilization of excitons, many organic systems have also emerged that show the potential to display long phosphorescence lifetimes (τP), but under ambient conditions, such systems usually show a significant reduction or complete loss of phosphorescence emission due to the active process of non-radiative decay of triplet excited states and oxygen quenching. Therefore, triplet excited states in common organic systems are not easily filled, but are easily quenched under ambient conditions. In the past decade, great efforts have been made to solve these problems.

[0004] The present invention has conducted in-depth research and found that charge transfer occurs between the donor and the acceptor to produce a charge separation state, and the generated long-lived charge transfer state is the main reason for achieving long-lived emission. In fact, the acceptor needs to have a very high triplet energy, providing a rigid amorphous environment to help suppress non-radiative deactivation. Such as dibenzothiophene groups. More importantly, we choose aromatic phosphine oxygen groups to modify the dibenzothiophene groups to further enhance the rigidity and steric hindrance of the molecule. Therefore, the energy loss caused by the non-radiative transition generated by the acceptor itself can be reduced, and the energy transfer formed between the guest molecules can be better dispersed. Summary of the invention

[0005] 1. Technical issues to be resolved

[0006] In view of the deficiencies in the prior art, the present invention provides a preparation method and application of a long afterglow material based on dibenzothiophene molecules. By using molecular design, a dibenzothiophene molecular material modified with aromatic phosphine oxide is provided. The dibenzothiophene molecules modified with aromatic phosphine oxide groups are used as acceptors, and are doped with donor molecules TMB to form a fuse film. By adjusting the modification sites and the number of phosphine oxide groups, the long afterglow life of the host-guest system can be adjusted. By using a traditional 365nm ultraviolet lamp for excitation, four dibenzothiophene molecules modified with aromatic phosphine oxides themselves have excellent long afterglow properties. At the same time, they are used as acceptor materials and TMB is used as a donor material. The fused forging film prepared further optimizes the afterglow properties, and achieves an organic afterglow with a longer emission time and brighter color, thereby completing the present invention.

[0007] (II) Technical solution

[0008] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0009] In the first aspect, the present invention provides a phosphorus-oxygen group-modified dibenzothiophene molecule (nDBTXPO), which is composed of compound 1, compound 2, compound 3 and compound 4, and the molecular structures of compound 1, compound 2, compound 3 and compound 4 are as follows:

[0010]

[0011] In a second aspect, the present invention provides a method for preparing a phosphorus-oxygen group-modified dibenzothiophene molecule (nDBTXPO), which specifically comprises the following steps:

[0012] S1. Under anhydrous and oxygen-free conditions, precursor 1 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in an ether solution of N,N,N',N'-tetramethylethylenediamine to obtain compounds 1 and 2;

[0013] S2, reacting with precursor 1 and liquid bromine in chloroform at room temperature to obtain precursor 2;

[0014] S3, reacting with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in tetrahydrofuran solution at -78°C to obtain compound 3;

[0015] S4, reacting with precursor 1 and liquid bromine in chloroform at 0°C to obtain compound 2;

[0016] S5. At -78°C, the precursor 3 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in a tetrahydrofuran solution to obtain compound 4.

[0017] Preferably, the structural formula of the precursor 1 in step S1 is as follows:

[0018]

[0019] Preferably, the structural formula of the precursor 2 in step S2 is as follows:

[0020]

[0021] Preferably, the structural formula of the precursor 3 in step S5 is as follows:

[0022]

[0023] Preferably, the method for preparing the dibenzothiophene molecule modified with phosphorus oxygen group specifically comprises the following steps:

[0024] T1. At -78°C, under anhydrous and oxygen-free conditions, n-butyl lithium was slowly added dropwise to an ether solution of precursor 1 and N,N,N',N'-tetramethylethylenediamine, and the reaction was allowed to proceed overnight; diphenylphosphine chloride was added dropwise and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, oxidized with hydrogen peroxide, extracted with water and dichloromethane, the organic layers were combined, dried, and purified by column chromatography using ethyl acetate-petroleum ether solvent as the eluent to obtain compound 1;

[0025] T2. At -78°C, under anhydrous and oxygen-free conditions, n-butyl lithium was slowly added dropwise to the ether solution of precursor 1 and N,N,N',N'-tetramethylethylenediamine, and the reaction was allowed to proceed overnight; diphenylphosphine chloride was added dropwise and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, oxidized with hydrogen peroxide, extracted with water and dichloromethane, the organic layers were combined, dried, and purified by column chromatography using ethyl acetate-petroleum ether solvent as the eluent to obtain compound 2;

[0026] T3. Under room temperature, liquid bromine was slowly added dropwise to the chloroform solution of precursor 1, and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, and the solid was washed with a saturated aqueous sodium bisulfite solution, dried, and purified by column chromatography using petroleum ether as an eluent to obtain precursor 2;

[0027] T4. Slowly add n-butyl lithium to the tetrahydrofuran solution of precursor 2 at -78°C in anhydrous and oxygen-free conditions. Maintain -78°C for two hours after the addition is complete; add diphenylphosphine chloride and react overnight. Extract with water and dichloromethane, combine the organic layers, oxidize the organic layers with hydrogen peroxide, dry, and purify by column chromatography using ethyl acetate-ethanol solvent as the eluent to obtain compound 3;

[0028] Under the conditions of T5 and 0°C, liquid bromine was slowly added dropwise to the chloroform solution of precursor 1, and the reaction was allowed to proceed overnight. After the reaction was completed overnight, the solid was filtered out, and the solid was washed with a saturated aqueous sodium bisulfite solution, dried, and purified by column chromatography using petroleum ether as an eluent to obtain precursor 3;

[0029] T6. Slowly add n-butyl lithium to the tetrahydrofuran solution of compound 1 at -78°C in anhydrous and oxygen-free conditions, and keep -78°C for two hours after the addition is completed; add diphenylphosphine chloride and react overnight. Extract with water and dichloromethane, combine the organic layers, oxidize the organic layers with hydrogen peroxide, dry, and purify by column chromatography with ethyl acetate-ethanol solvent as eluent to obtain compound 4.

[0030] In a third aspect, the present invention also provides an application of an organic long afterglow luminescent compound prepared by a preparation method of a dibenzothiophene molecule modified with a phosphorus oxygen group in the preparation of a melt-forged film, specifically comprising the following steps:

[0031] E1. The phosphorus-oxygen-modified dibenzothiophene molecules were placed on a quartz substrate and heated to between 190 and 300 °C for 10 seconds in a glove box. After melting, the substrate was quickly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover under a nitrogen atmosphere.

[0032] E2. The donor N, N, N′, N′-tetramethylbenzidine and the acceptor phosphorus oxygen group-modified dibenzothiophene molecules were doped in a ratio of 1:99, placed on a quartz substrate, and heated to between 190-300°C for 10 seconds in a glove box. After melting, the substrate was quickly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover under a nitrogen atmosphere.

[0033] Preferably, the step E2 specifically includes the following steps:

[0034] P1, doping donor acceptor powder at a ratio of 1:99;

[0035] P2, heating in the glove box;

[0036] P3, cool to room temperature;

[0037] P4, UV curing packaging to obtain organic long afterglow luminescent melt-forged film.

[0038] Preferably, the step E2 specifically includes the following steps:

[0039] U1. Preparation of doped donor-acceptor powder: donor-acceptor powder is doped at a ratio of 1:99;

[0040] U2. Fabrication of organic long afterglow luminescent melt-forged film: placed on a quartz substrate and heated to between 190-300°C in a glove box for 10 seconds. After melting, the substrate was rapidly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover in a nitrogen atmosphere.

[0041] (III) Beneficial effects

[0042] The present invention provides a preparation method and application of a long afterglow material based on dibenzothiophene molecules. Compared with the prior art, it has the following beneficial effects:

[0043] (1) The preparation method and application of the long afterglow material based on dibenzothiophene molecules, the provided organic long afterglow luminescent compound of dibenzothiophene molecules modified with aromatic phosphine oxygen groups, with dibenzothiophene as the chromophore and aromatic phosphine oxygen as the modification, four kinds of organic long afterglow luminescent compounds were constructed, and at the same time, the organic long afterglow luminescent compound of dibenzothiophene molecules modified with aromatic phosphine oxygen provided by the present invention, the steric hindrance effect of the phosphine oxygen group effectively inhibited the quenching effect caused by the interaction between molecules;

[0044] (2) The preparation method and application of the long afterglow material based on dibenzothiophene molecules, the organic long afterglow luminescent compound of the dibenzothiophene molecules modified by aromatic phosphine oxide, can make full use of triplet excitons and significantly improve the life and efficiency of the organic long afterglow melt-forged film. At the same time, the organic long afterglow luminescent compound of the dibenzothiophene molecules modified by aromatic phosphine oxide provided by the present invention can adjust the charge transfer process with the donor molecule by adjusting the number and position of the phosphine oxide groups, and can control the length of the organic long afterglow emission lifetime.

[0045] (3) The preparation method and application of the long afterglow material based on dibenzothiophene molecules provide an organic long afterglow luminescent compound of aromatic phosphine oxide modified dibenzothiophene molecules, which has an easy synthesis route, is easy to control, and has a simple preparation method, and can prepare the target molecular product. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The lifetime decay diagram of the melt-forged film prepared by compounds 1-4 in Example 1 of the present invention is shown;

[0047] Figure 2 The figure shows the life decay diagram of the melt-forged film prepared by compound 1-4+TMB in Example 1 of the present invention;

[0048] Figure 3 The fluorescence image of the melt-forged film prepared by compound 1-4 in Example 1 of the present invention is shown;

[0049] Figure 4 The phosphorescence image of the melt-forged film prepared by compound 1-4 in Example 1 of the present invention is shown;

[0050] Figure 5 The fluorescence image of the melt-forged film prepared by compound 1-4 + TMB in Example 1 of the present invention is shown.

[0051] Figure 6 The phosphorescence image of the melt-forged film prepared by compound 1-4 + TMB in Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0052] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0053] See also Figure 1-6 The embodiments of the present invention provide four technical solutions: a preparation method and application of a long afterglow material based on dibenzothiophene molecules, specifically including the following embodiments:

[0054] Example 1: Under room temperature, liquid bromine was slowly added dropwise to the chloroform solution of precursor 1, and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, and the solid was washed with a saturated aqueous sodium bisulfite solution, dried, and purified by column chromatography using petroleum ether as the eluent to obtain precursor 2.

[0055] At -78°C, in anhydrous and oxygen-free conditions, n-butyl lithium was slowly added dropwise to the tetrahydrofuran solution of precursor 2, and the temperature was kept at -78°C for two hours after the addition was completed; diphenylphosphine chloride was added dropwise and the reaction was allowed to proceed overnight. The mixture was extracted with water and dichloromethane, and the organic layers were combined, oxidized with hydrogen peroxide, dried, and purified by column chromatography using ethyl acetate-ethanol solvent as the eluent to obtain compound 3

[0056] Compound 3 was analyzed by hydrogen nuclear magnetic resonance spectrum, and the test data were: 1 H NMR (TMS, CDCl3, 400MHz): δ = 8.48 (d, J = 12.0Hz, 1H), 7.98-7.96 (dd, J1 = 2.4Hz, J2 = 8.4Hz 2H), 7.80-7.67 (m, 10H), 7.59-7.55 (td, J1 = 1.2Hz, J2 = 7.2Hz 4H),7.50-7.46(m,8H).

[0057] The organic long afterglow melt-forged film was prepared with compound 3, and the process was as follows:

[0058] 1. Prepare compound 3 powder (100 mg);

[0059] 2. Heat the heating stage to 250°C and place it on the quartz substrate

[0060] 3. Heating in the glove box;

[0061] 4. Cool to room temperature;

[0062] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0063] The test showed that the organic long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation is stopped, which shows that the compound 3 melt-forged film has the organic long afterglow characteristics.

[0064] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0065] 15.79s (33.10%), 117.68s (66.9%).

[0066] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 490nm, and the photoluminescence phosphorescence peak is at 495nm.

[0067] The organic doped long afterglow melt-forged film was prepared using compound 3 as the acceptor and TMB as the donor. The process is as follows:

[0068] 1. Prepare powder (100 mg) with a donor-recipient ratio of 1:99;

[0069] 2. Heat the heating stage to 250°C and place it on the quartz substrate

[0070] 3. Heating in the glove box;

[0071] 4. Cool to room temperature;

[0072] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0073] The test shows that the organic doped long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation stops, which shows that the doped melt-forged film of compound 3 and TMB has the organic long afterglow characteristic.

[0074] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0075] 34.09s (32.6%), 219.53s (67.4%).

[0076] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 530nm, and the photoluminescence phosphorescence peak is at 530nm.

[0077] Example 2: Under -78°C, in the absence of water and oxygen, precursor 1 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in an ether solution of N,N,N',N'-tetramethylethylenediamine to obtain compound 1.

[0078] Compound 1 was analyzed by hydrogen nuclear magnetic resonance spectrum, and the test data were:

[0079] 1H NMR (400MHz, CDCl3, TMS): δ (ppm) 8.62-8.59 (d, J = 12Hz, 1H); 8.13-8.11 (d, J = 8Hz, 1H); 7.92-7.85 (dd, J1 = 8.0Hz, J2 = 8.0Hz 2H); 7.73-7.68 (m, 4H); 7.60-7.54 (dd, J1 = 8.0Hz, J2 = 8.0Hz 3H); 7.49-7.45 (t, J = 12Hz, 6H).

[0080] The organic long afterglow melt-forged film was prepared using compound 1, and the process was as follows:

[0081] 1. Prepare compound 1 powder (100 mg);

[0082] 2. Heat the heating stage to 300°C and place it on the quartz substrate

[0083] 3. Heating in the glove box;

[0084] 4. Cool to room temperature;

[0085] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0086] The test showed that the organic long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation is stopped, which shows that the compound 1 melt-forged film has the organic long afterglow characteristic.

[0087] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0088] 1.8s (34.89%), 10.60s (65.11%).

[0089] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 390nm, and the photoluminescence phosphorescence peak is at 558nm.

[0090] The organic doped long afterglow melt-forged film was prepared using compound 1 as the acceptor and TMB as the donor. The process is as follows:

[0091] 1. Prepare powder (100 mg) with a donor-recipient ratio of 1:99;

[0092] 2. Heat the heating stage to 300°C and place it on the quartz substrate

[0093] 3. Heating in the glove box;

[0094] 4. Cool to room temperature;

[0095] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0096] The test shows that the organic doped long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation stops, which shows that the doped melt-forged film of compound 1 and TMB has the organic long afterglow characteristic.

[0097] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0098] 24.59s (36.7%) 142.59s (63.3%).

[0099] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 530nm, and the photoluminescence phosphorescence peak is at 530nm.

[0100] Example 3: Under -78°C, in the absence of water and oxygen, precursor 1 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in an ether solution of N,N,N',N'-tetramethylethylenediamine to obtain compound 2.

[0101] Compound 2 was analyzed by nuclear magnetic resonance hydrogen spectrum, and the test data were:

[0102] 1 H NMR (400MHz, CDCl3, TMS): δ (ppm) 8.47-8.44 (d, J = 12Hz, 2H); 8.96-8.94 (d, J = 8H z, 2H); 7.77-7.65 (m, 10H); 7.57-7.53 (t, J = 16Hz, 4H); 7.48-7.46 (d, J = 8Hz, 8H).

[0103] The organic long afterglow melt-forged film was prepared with compound 2, and the process was as follows:

[0104] 1. Prepare compound 2 powder (100 mg);

[0105] 2. Heat the heating stage to 300°C and place it on the quartz substrate

[0106] 3. Heating in the glove box;

[0107] 4. Cool to room temperature;

[0108] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0109] The test shows that the organic long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation stops, which shows that the compound 2 melt-forged film has the organic long afterglow characteristic.

[0110] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0111] 9.02s (36.55%) 58.10s (63.45%).

[0112] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 394nm, and the photoluminescence phosphorescence peak is at 554nm.

[0113] The organic doped long afterglow melt-forged film was prepared using compound 2 as the acceptor and TMB as the donor. The process is as follows:

[0114] 1. Prepare powder (100 mg) with a donor-recipient ratio of 1:99;

[0115] 2. Heat the heating stage to 300°C and place it on the quartz substrate

[0116] 3. Heating in the glove box;

[0117] 4. Cool to room temperature;

[0118] 5. Ultraviolet light curing packaging to obtain organic doped long afterglow luminescent melt-forged film.

[0119] The test shows that the organic doped long afterglow luminescent melt-forged film can still continue to emit light after the ultraviolet light excitation stops, which shows that the doped melt-forged film of compound 1 and TMB has the organic long afterglow characteristic.

[0120] The lifetime decay trend of the organic long afterglow luminescent melt-forged film was tested, and the maximum lifetime of the device was found to be

[0121] 25.58s (36.0%) 161.3s (64.0%).

[0122] Depend on Figure 5 It can be seen that the photoluminescence peak of the device is at 530nm, and the photoluminescence phosphorescence peak is at 530nm.

[0123] Example 4: The synthesis steps are the same as those in Example 1.

[0124] Compound 4 was analyzed by hydrogen nuclear magnetic resonance spectrum, and the test data were: 1 H NMR (TMS, CDCl3, 400MHz): δ=8.65-8.62 (d, J=12.0Hz, 1H), 8.16-8.14 (d, J=8.0Hz, 1H), δ=7.95-7.93 (d, J=8.0H z,1H)7.89-7.87(d,J=8.0Hz,1H),7.76-7.71(dd,J1=8.0Hz,J2=8.0Hz4H),7.63-7.57(dd,J1=8.0Hz,J2=8.0Hz 3H),7.50-7.46(m,6H).

[0125] The present invention is described in detail above in conjunction with specific embodiments and / or exemplary examples and drawings, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, various equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0126] Meanwhile, the contents not described in detail in this specification belong to the prior art known to those skilled in the art.

[0127] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0128] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dibenzothiophene molecule modified with a phosphorus oxygen group, characterized in that: It is composed of compound 1, compound 2, compound 3 and compound 4, and the molecular structures of compound 1, compound 2, compound 3 and compound 4 are as follows:

2. A method for preparing a phosphorus-oxygen group-modified dibenzothiophene molecule according to claim 1, characterized in that: The specific steps include: S1. Under anhydrous and oxygen-free conditions, precursor 1 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in an ether solution of N,N,N',N'-tetramethylethylenediamine to obtain compounds 1 and 2; S2, reacting with precursor 1 and liquid bromine in chloroform at room temperature to obtain precursor 2; S3, reacting with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in tetrahydrofuran solution at -78°C to obtain compound 3; S4, reacting with precursor 1 and liquid bromine in chloroform at 0°C to obtain compound 2; S5. At -78°C, the precursor 3 reacts with n-butyl lithium, diphenylphosphine chloride and hydrogen peroxide in a tetrahydrofuran solution to obtain compound 4.

3. The method for preparing the phosphorus-oxygen group-modified dibenzothiophene molecule according to claim 2, characterized in that: The structural formula of the precursor 1 in step S1 is as follows:

4. The method for preparing the dibenzothiophene molecule modified with phosphorus oxygen group according to claim 2, characterized in that: The structural formula of the precursor 2 in step S2 is as follows:

5. The method for preparing the dibenzothiophene molecule modified with phosphorus oxygen group according to claim 2, characterized in that: The structural formula of the precursor 3 in step S5 is as follows:

6. The method for preparing the dibenzothiophene molecule modified with phosphorus oxygen group according to claim 2, characterized in that: The specific steps include: T1. At -78°C, under anhydrous and oxygen-free conditions, n-butyl lithium was slowly added dropwise to an ether solution of precursor 1 and N,N,N',N'-tetramethylethylenediamine, and the reaction was allowed to proceed overnight; diphenylphosphine chloride was added dropwise and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, oxidized with hydrogen peroxide, extracted with water and dichloromethane, the organic layers were combined, dried, and purified by column chromatography using ethyl acetate-petroleum ether solvent as the eluent to obtain compound 1; T2. At -78°C, under anhydrous and oxygen-free conditions, n-butyl lithium was slowly added dropwise to the ether solution of precursor 1 and N,N,N',N'-tetramethylethylenediamine, and the reaction was allowed to proceed overnight; diphenylphosphine chloride was added dropwise and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, oxidized with hydrogen peroxide, extracted with water and dichloromethane, the organic layers were combined, dried, and purified by column chromatography using ethyl acetate-petroleum ether solvent as the eluent to obtain compound 2; T3. Under room temperature, liquid bromine was slowly added dropwise to the chloroform solution of precursor 1, and the reaction was allowed to proceed overnight. After the reaction was allowed to proceed overnight, the solid was filtered out, and the solid was washed with a saturated aqueous sodium bisulfite solution, dried, and purified by column chromatography using petroleum ether as an eluent to obtain precursor 2; T4. Slowly add n-butyl lithium to the tetrahydrofuran solution of precursor 2 at -78°C in anhydrous and oxygen-free conditions. Maintain -78°C for two hours after the addition is complete; add diphenylphosphine chloride and react overnight. Extract with water and dichloromethane, combine the organic layers, oxidize the organic layers with hydrogen peroxide, dry, and purify by column chromatography using ethyl acetate-ethanol solvent as the eluent to obtain compound 3; Under the conditions of T5 and 0°C, liquid bromine was slowly added dropwise to the chloroform solution of precursor 1, and the reaction was allowed to proceed overnight. After the reaction was completed overnight, the solid was filtered out, and the solid was washed with a saturated aqueous sodium bisulfite solution, dried, and purified by column chromatography using petroleum ether as an eluent to obtain precursor 3; T6. Slowly add n-butyl lithium to the tetrahydrofuran solution of compound 1 at -78°C in anhydrous and oxygen-free conditions, and keep -78°C for two hours after the addition is completed; add diphenylphosphine chloride and react overnight. Extract with water and dichloromethane, combine the organic layers, oxidize the organic layers with hydrogen peroxide, dry, and purify by column chromatography with ethyl acetate-ethanol solvent as eluent to obtain compound 4.

7. Use of an organic long afterglow luminescent compound obtained by the method for preparing a phosphorus-oxygen group-modified dibenzothiophene molecule according to any one of claims 2 to 6 in preparing a melt-forged film, characterized in that: The specific steps include: E1. The phosphorus-oxygen-modified dibenzothiophene molecules were placed on a quartz substrate and heated to between 190 and 300 °C for 10 seconds in a glove box. After melting, the substrate was quickly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover under a nitrogen atmosphere. E2. The donor N, N, N′, N′-tetramethylbenzidine and the acceptor phosphorus oxygen group-modified dibenzothiophene molecules were doped in a ratio of 1:99, placed on a quartz substrate, and heated to between 190-300°C for 10 seconds in a glove box. After melting, the substrate was quickly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover under a nitrogen atmosphere.

8. The use of the organic long afterglow luminescent compound obtained by the preparation method of the phosphorus oxygen group-modified dibenzothiophene molecule according to claim 7 in the preparation of a melt-forged film, characterized in that: The step E2 specifically includes the following steps: P1, doping donor acceptor powder at a ratio of 1:99; P2, heating in the glove box; P3, cool to room temperature; P4, UV curing packaging to obtain organic long afterglow luminescent melt-forged film.

9. The use of the organic long afterglow luminescent compound obtained by the preparation method of the phosphorus oxygen group-modified dibenzothiophene molecule according to claim 8 in the preparation of a melt-forged film, characterized in that: The step E2 specifically includes the following steps: U1. Preparation of doped donor-acceptor powder: donor-acceptor powder is doped at a ratio of 1:99; U2. Fabrication of organic long afterglow luminescent melt-forged film: placed on a quartz substrate and heated to between 190-300°C in a glove box for 10 seconds. After melting, the substrate was rapidly cooled to room temperature and encapsulated using UV-cured epoxy resin and a glass cover in a nitrogen atmosphere.

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