Efficient narrow-band emission material embedded with dibenzothiophene, preparation method and application thereof

Abstract

The present invention belongs to the technical field of organic light-emitting materials, and relates to a highly efficient narrow-band light-emitting material embedded with dibenzothiophene, its preparation method and application. The light-emitting material has the structure shown in the following general formula (I): #imgabs0# (I), wherein R6 is #imgabs1#, #imgabs2#, #imgabs3#, #imgabs4#, #imgabs5# or #imgabs6#. This material can maintain the emission peak in the green light range while having a narrow full width at half maximum, so as to achieve green light output meeting the BT.2020 color purity standard.

Description

Technical Field

[0001] The invention belongs to the technical field of organic luminescent materials, and relates to a high-efficiency narrow-band luminescent material embedded with dibenzothiophene, and a preparation method and application thereof. Background Art

[0002] Under the exquisite framework of quantum spin statistics, the electroluminescence phenomenon reveals a striking phenomenon: among its products, singlet excitons account for only 25%, while the remaining 75% are triplet excitons. However, the law of nature - spin prohibition, has built a high wall in conventional organic matrices, making it impossible for these two types of excitons to cross the gap and convert into each other. Singlet excitons are fortunately the only messenger of fluorescence, and triplet excitons cannot be directly converted into singlet excitons and emit photons, causing this part of the energy to be dissipated in the form of heat.

[0003] In order to release the potential of the 75% wasted excitons, scientists introduced heavy metals - that is, to create complexes as a solution. By using the unique spin-orbit coupling effect between heavy metals and their ligands, the shackles of electron spins are cleverly broken, allowing singlet excitons to completely transition to triplet states, resulting in phosphorescent luminescent materials with an internal quantum efficiency of nearly 100%. However, the road to phosphorescence is not an easy one. The short life of the materials, the high cost and the toxicity of the heavy metals themselves are all problems that need to be solved urgently.

[0004] In this context, thermally activated delayed fluorescence (TADF) technology came into being. It does not require the use of heavy metals, but can also achieve a nearly perfect 100% internal quantum efficiency. This breakthrough quickly attracted the attention of industry and academia. Back in 2011, the emergence of PIC-TRZ, a pure aromatic compound, marked the initial victory of TADF technology. It showed a maximum external quantum efficiency (EQE) of 5.3% at low current density. Time flies, and TADF materials are no longer what they used to be. Its luminous colors span the entire visible spectrum, and its EQE has jumped to a new height of more than 37%, showing extraordinary growth potential.

[0005] Traditional TADF strategies mostly rely on donor-acceptor (DA) structures, which promote the use of triplet excitons through twisted configurations within the molecule. However, this distortion also limits the fluorescence quantum yield of the material. To this end, scientists have taken a different approach and used electron-deficient B elements and electron-rich fifth and sixth group elements to construct multi-resonance (MR) TADF materials. This innovation not only solves the dilemma of traditional materials, but also gives the material a narrower half-width and higher color purity.

[0006] However, MR-TADF materials are not perfect either. Their good planarity leads to strong intermolecular interactions in the stacked state, and problems such as spectral red-shift and emission broadening are likely to occur at high doping concentrations. Therefore, when preparing organic light-emitting diodes (OLEDs), the doping concentration of MR-TADF materials needs to be extremely precisely controlled to obtain ideal optoelectronic properties. However, this requirement undoubtedly increases the difficulty and cost of device preparation, becoming another challenge restricting its wide application. Nevertheless, the unique advantages and potential demonstrated by MR-TADF materials still make scientists full of expectations and confidence for its future.

[0007] With the development of the times, the rapid rise of the global digital economy has put forward higher requirements for high-definition display technology. The ultra-high-definition television recommendation standard (BT.2020) issued by the International Telecommunication Union emerged as the latest high-definition display technology standard. However, traditional fluorescence emission devices mainly rely on local excitation characteristics, and for commercial materials used in organic light-emitting devices (OLEDs), the full width at half maximum (FWHM) is approximately 50 nm. Although using color filters or optical microcavities can effectively meet the color purity standard, this method significantly affects the efficiency and stability of the device.

[0008] OLED devices based on MR-TADF materials have natural advantages in solving the above problems, which further promotes their vigorous development. Currently, OLED devices based on MR-TADF luminescent materials have basically achieved full-spectrum coverage, but there is still a large gap in the green light field to meet the BT.2020 standard. Therefore, it is urgent to conduct in-depth research and solve this problem. Summary of the Invention

[0009] The present invention aims at the deficiencies of lithium batteries in the prior art and provides a highly efficient narrow-band luminescent material embedded with dibenzothiophene. This material can maintain the emission peak within the green light range while having a narrow full width at half maximum, thereby achieving green light output that meets the BT.2020 color purity standard.

[0010] One object of the present invention is achieved through the following technical solutions:

[0011] A highly efficient narrow-band luminescent material embedded with dibenzothiophene, the luminescent material having a structure shown in the following general formula (I):

[0012] (I),

[0013] Wherein, R 6 is , , , , or ; R 1 , R 2 , R 3 , R 4 , R 5 Each of the following is independently selected from one or more of H, F, Br, Cl, CN, a straight-chain alkyl group having 1 to 30 carbon atoms, a branched-chain alkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic ring consisting of carbon and hydrogen, an aromatic heterocycle consisting of carbon, nitrogen and hydrogen, an aromatic heterocycle consisting of carbon, oxygen and hydrogen, an aromatic heterocycle consisting of carbon, sulfur and hydrogen, and an aromatic heterocycle consisting of carbon, nitrogen, sulfur and hydrogen.

[0014] * indicates the attachment site.

[0015] Preferably, R 1 , R 2 , R 3 , R 4 , R 5 It is selected from two groups, one group is H, and the other group is one of F, Br, Cl, CN, and an aromatic ring composed of carbon and hydrogen.

[0016] Preferably, the luminescent material has a structure as shown in any one of the following formulas (1) to (25):

[0017] .

[0018] Preferably, the maximum emission wavelength of the luminescent material is 510-520 nm, and the full width at half maximum (FWHM) is ≤20 nm, for example, it can be 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 nm. More preferably, the full width at half maximum is 10-16 nm.

[0019] The present invention uses dibenzothiophene as the core to construct a class of boronized molecules with a symmetrical structure. By utilizing the steric effect generated by the large opening angle within the dibenzothiophene molecule, a significant large dihedral angle is formed with the connected electron-donating phenylboronic acid unit, thereby effectively reducing the influence of the CT effect on the narrow emission characteristics of the MR-TADF luminescent material. At the same time, according to the frontier molecular orbital engineering (FMOE) strategy, the introduction of electron-donating groups at the LUMO position of the skeleton periphery can cause the emission spectrum of the molecule to red-shift and the band gap to narrow, ultimately achieving the goal of improving color purity and ultra-high-definition display of the device.

[0020] The second object of the present invention is achieved by the following technical solutions:

[0021] The method for preparing a high-efficiency narrow-band luminescent material embedded with dibenzothiophene comprises the following steps:

[0022] S1, using 2-bromodibenzothiophene as a raw material, a series of CN coupling reactions were performed to synthesize an intermediate 3 having the following structural formula (28);

[0023] S2 and intermediate 3 are dissolved in a solvent and reacted under the action of a boron halide to generate intermediate 4 shown in the following structural formula (29);

[0024] S3, intermediate 4 and phenylboronic acid derivatives undergo Suzuki coupling reaction to obtain the final luminescent material;

[0025] (28); (29).

[0026] Preferably, step S1 comprises the following steps:

[0027] S1-1, 2-bromodibenzothiophene and 2,4,6-trimethylaniline react under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain an intermediate 1 having the following structural formula (26):

[0028] (26).

[0029] In step S1-1, preferably, the molar ratio of 2-bromodibenzothiophene to 2,4,6-trimethylaniline is 1:1-3. Preferably, the reaction temperature is 90-150°C, and the reaction time is 5-40h. After the reaction is completed, the reaction solution is filtered and washed, and the concentrated solid is further separated and purified using a chromatographic column.

[0030] S1-2, intermediate 1 and 1,3-dibromo-5-chlorobenzene react under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain intermediate 2 having the following structural formula (27):

[0031] (27).

[0032] In step S1-2, preferably, the molar ratio of intermediate 1 to 1,3-dibromo-5-chlorobenzene is 1:0.5-2. Preferably, the reaction temperature is 90-150° C., and the reaction time is 5-40 hours. After the reaction is completed, the reaction solution is filtered and washed, and the concentrated solid is further separated and purified using a chromatographic column.

[0033] S1-3, intermediate 2 and N1, N3-di-p-toluene-1, 3-diamine are reacted under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain intermediate 3.

[0034] In step S1-3, preferably, the molar ratio of intermediate 2 to N1, N3-di-p-toluene-1,3-diamine is 2-4:1. Preferably, the reaction temperature is 90-150° C., and the reaction time is 5-40 hours. After the reaction is completed, the reaction solution is filtered and washed, and the concentrated solid is further separated and purified using a chromatographic column.

[0035] The CN coupling reaction in step S1 is carried out under the conditions including solvent, catalyst, catalyst ligand and base. The solvent, catalyst, catalyst ligand and base are solvents, catalysts, catalyst ligands and bases available in any CN coupling reaction. Preferably, the solvent is one or more of o-xylene, p-xylene, m-xylene, o-dichlorobenzene, 1,3,5-mesitylene, toluene, etc. The catalyst is a palladium catalyst, and the palladium catalyst includes tris(dibenzylideneacetone)dipalladium [Pd 2 (dba) 3 ], tetrakis(triphenylphosphine)palladium[Pd(PPh 3 ) 4 ], bis(triphenylphosphine)palladium dichloride (Pd(PPh 3 ) 2 Cl 2 ), bis(palladium acetate)[Pd(OAc) 2 ], etc. Catalyst ligands include phosphorus ligands, nitrogen ligands, carbon ligands, oxygen ligands, heteroatom ligands, etc., and can be listed as tri-tert-butylphosphine tetrafluoroborate (t-Bu 3 PHB 4 ), triphenylphosphine (PPh 3 ), 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (XPhos), 2-dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl (SPhos), 2-dicyclohexylphosphino-2',6'-diisopropyloxy-1,1'-biphenyl (Ru-Phos), etc. The base is one or more of potassium carbonate, cesium carbonate, sodium sec-butoxide (s-BuONa), sodium tert-butoxide (t-BuONa), etc.

[0036] In step S2, preferably, the boron halide is BBr 3 , BI 3 or BCl 3 One or more of. Preferably, the molar ratio of intermediate 3 to boron halide is 1:1-20. Preferably, the solvent is one or more of dichlorobenzene, isotrichlorobenzene, n-butyl ether, phenyl ether, etc. Preferably, the reaction temperature is 180-250°C, and the reaction time is 10-50h. Preferably, after the reaction in step (2) is completed, an alcohol reagent is added for quenching, and the alcohol reagent can be listed as one or more of methanol, ethanol, isopropanol, n-butanol, etc.

[0037] After the reaction in step S2 is completed, optionally, post-treatment is performed, and the post-treatment includes: concentrating the reaction solution, and further purifying the residual solid by a chromatographic column.

[0038] In step S3, preferably, the molar ratio of intermediate 4 to phenylboronic acid derivative is 1:2~10. The Suzuki coupling reaction is carried out under the conditions of solvent, catalyst and base, and the solvent, catalyst and base are any solvent, catalyst and base that can be used in Suzuki coupling reaction. Preferably, the solvent is one or more of o-xylene, p-xylene, m-xylene, o-dichlorobenzene, 1,3,5-mesitylene, toluene, etc. The catalyst is a palladium catalyst, and the palladium catalyst includes tris(dibenzylideneacetone)dipalladium [Pd 2 (dba) 3 ], tetrakis(triphenylphosphine)palladium[Pd(PPh 3 ) 4 ], bis(triphenylphosphine)palladium dichloride (Pd(PPh 3 ) 2 Cl 2 ), bis(palladium acetate)[Pd(OAc) 2 ] and the like. The base is one or more of potassium carbonate, cesium carbonate, sodium sec-butoxide (s-BuONa) and sodium tert-butoxide (t-BuONa). The temperature of the Suzuki coupling reaction is 70-150°C, and the time is 5-50h. Appropriate reaction parameters are selected according to different phenylboronic acid derivatives. After the Suzuki coupling reaction of step S3 is completed, optionally, post-treatment is performed, and the post-treatment includes: concentrating the reaction solution, extracting and washing the residual solid with water, and then further concentrating it, and the obtained solid is purified by a chromatographic column.

[0039] Preferably, the phenylboronic acid derivative has a structure shown in the following general formula (II):

[0040] (II),

[0041] R 1 , R 2 , R 3 , R 4 , R 5 Each of the following is independently selected from one or more of H, F, Br, Cl, CN, a straight-chain alkyl group having 1 to 30 carbon atoms, a branched-chain alkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic ring consisting of carbon and hydrogen, an aromatic heterocycle consisting of carbon, nitrogen and hydrogen, an aromatic heterocycle consisting of carbon, oxygen and hydrogen, an aromatic heterocycle consisting of carbon, sulfur and hydrogen, and an aromatic heterocycle consisting of carbon, nitrogen, sulfur and hydrogen.

[0042] Preferably, the phenylboronic acid derivative is a compound represented by any one of formulas (1') to (25'):

[0043] .

[0044] When the phenylboronic acid derivative is a compound of formula (1'), the structural formula of the prepared luminescent material is as shown in formula (1); when the phenylboronic acid derivative is a compound of formula (2'), the structural formula of the prepared luminescent material is as shown in formula (2); and similarly, when the phenylboronic acid derivative is a compound of formula (25'), the structural formula of the prepared luminescent material is as shown in formula (25).

[0045] Preferably, the entire reaction process is carried out under an inert atmosphere, which includes nitrogen, argon, and the like.

[0046] The third object of the present invention is achieved by the following technical solutions:

[0047] An organic electroluminescent device, wherein the luminescent layer of the organic electroluminescent device comprises one or more high-efficiency narrow-band luminescent materials embedded with dibenzothiophene.

[0048] Preferably, the organic electroluminescent device comprises an ITO substrate, an anode layer, an organic functional layer and a cathode layer in sequence; wherein the organic functional layer comprises one or more hole injection layers, one or more hole transport layers, one or more light-emitting layers and one or more electron transport layers; the light-emitting layer comprises one or more high-efficiency narrow-band light-emitting materials embedded with dibenzothiophene. Each layer is prepared by one or more methods including thermal evaporation and spin coating.

[0049] Further preferably, the organic functional layer includes one or more hole injection layers, one or more hole transport layers, one or more exciton blocking layers, one or more light-emitting layers, one or more electron transport layers, and one or more electron injection layers.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] 1. The luminescent material provided by the present invention has a dibenzothiophene unit embedded on the basis of the traditional MR-TADF core, and its electroluminescence peak is in the range of 510-520nm. It belongs to a type of organic green light guest material that meets the BT.2020 standard, and provides an important reference for the commercial application of green light materials. At the same time, it has a narrow-band luminescence characteristic, which significantly improves the electronic transmission performance of the material, and has an important synergistic effect on the manufacture of high-efficiency narrow-band green light OLED devices.

[0052] 2. The present invention improves the physical and chemical properties of the luminescent material by adjusting the modifying groups on the aromatic structure. Experimental results show that the synthesized compound is insensitive to water and oxygen, exhibits good solubility in common organic solvents, and exhibits excellent thermodynamic stability and outstanding photochemical stability, thereby giving it more excellent performance in organic semiconductor devices.

[0053] 3. After the luminescent material of the present invention is prepared into an organic light-emitting diode, the material exhibits high-efficiency luminescent performance, significantly improved quantum efficiency, a narrow-bandwidth emission spectrum, and superior characteristics of low sensitivity to doping concentration.

[0054] 4. The present invention synthesizes a series of MR-TADF luminescent materials through a simple and efficient coupling reaction. The preparation method provided has the significant advantages of simple operation, mild reaction conditions, suitability for large-scale production and strong adaptability to substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 3 in toluene solution;

[0056] Figure 2 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 4 in toluene solution;

[0057] Figure 3 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 5 in toluene solution;

[0058] Figure 4 is a current density-voltage-brightness relationship curve of the organic electroluminescent device of Application Example 1;

[0059] Figure 5 is a current efficiency-brightness relationship curve diagram of the organic electroluminescent device of Application Example 1;

[0060] Figure 6 This is a light emission spectrum diagram of the organic electroluminescent device of Application Example 1. DETAILED DESCRIPTION

[0061] The technical scheme of the present invention is further described below by specific examples and accompanying drawings. It should be understood that the specific examples described herein are only used to help understand the present invention and are not intended for specific limitations of the present invention. The accompanying drawings used herein are only for better illustrating the disclosure of the present invention and do not have a limiting effect on the scope of protection. If not otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.

[0062] Example 1

[0063] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (1), and the preparation method thereof comprises the following steps:

[0064] (1) In a 100 mL three-necked round-bottomed reaction flask filled with argon, 2-bromodibenzo[b,d]thiophene (20.0 mmol), 2,4,6-trimethylaniline (24.0 mmol), Pd 2 (dba) 3 A mixture of (0.4 mol), X-Phos (1.0 mol), t-BuONa (15.0 mmol) and 50 mL of toluene was stirred at 110 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the remaining solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure light brown solid intermediate 1 (5.70 g, 18.0 mmol, yield 90%).

[0065] (2) In a 100 mL three-necked round-bottomed reaction flask filled with argon, intermediate 1 (20.0 mmol), 1,3-dibromo-5-chlorobenzene (15.0 mmol), Pd 2 (dba) 3 (0.4 mol), S-Phos (1.0 mol), t-BuONa (30.0 mmol) and 50 mL of toluene were stirred at 100 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the remaining solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure white solid intermediate 2 (7.10 g, 14.0 mmol, yield 70%).

[0066] (3) In a 100 mL three-necked round-bottomed reaction flask filled with argon, add N 1 , N 3 - di-p-toluene-1,3-diamine (5.0 mmol), intermediate 2 (12.5 mmol), Pd 2 (dba) 3 (0.15 mol), Ru-Phos (0.25 mol), t-BuONa (15.0 mmol) and 80 mL of toluene were stirred at 120 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the residual solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure white solid intermediate 3 (3.71 g, 3.25 mmol, yield 65%).

[0067] (4) In a 120 mL argon-sealed pressure tube, intermediate 3 (2.0 mmol) and 15 mL dichlorobenzene (o-DCB) were added, followed by boron bromide (20.0 mmol), and the reaction was stirred at 200 °C for 36 h. After cooling to room temperature, ethanol reagent (5.0 mL) was slowly added in an ice bath to quench the reaction. The organic solvent was concentrated under vacuum, and the residual solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) column chromatography to obtain a pure dark yellow solid intermediate 4 (0.93 g, 0.80 mmol, yield 40%).

[0068] (5) In a 120 mL argon sealed pressure tube, add intermediate 4 (1.0 mmol), [1,1':3',1'-triphenyl]-5'-boronic acid (3.0 mol), Pd(PPh 3 ) 4 (0.1 mol), K 2 CO 3 (3.0 mol) and 40 ml tetrahydrofuran, 10 ml water, and then stirred at 100 ° C for overnight reaction. Then, it was cooled to room temperature, the organic solvent was concentrated under vacuum conditions, the residual solid was extracted with dichloromethane and washed with water, and the organic solvent was concentrated again under vacuum conditions. The obtained solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure bright yellow solid product 1 (0.77 g, 0.50 mmol, yield 50%).

[0069] The reaction flow chart of steps (1) to (5) of Example 1 is as follows:

[0070] .

[0071] Example 2

[0072] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (2), and the preparation method thereof comprises the following steps:

[0073] (1) In a 100 mL three-necked round-bottomed reaction flask filled with argon, 2-bromodibenzo[b,d]thiophene (20.0 mmol), 2,4,6-trimethylaniline (25.0 mmol), Pd 2 (dba) 3 (0.5mol), t-Bu 3 PHB 4A mixture of (2.0 mol), t-BuONa (30.0 mmol) and 80 mL of toluene was stirred at 120 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the remaining solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure light brown solid intermediate 1 (yield 89%).

[0074] (2) In a 100 mL three-necked round-bottomed reaction flask filled with argon, intermediate 1 (20.0 mmol), 1,3-dibromo-5-chlorobenzene (24.0 mmol), Pd 2 (dba) 3 (0.5 mol), S-Phos (1.0 mol), t-BuONa (30.0 mmol) and 70 mL of toluene were stirred at 110 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the remaining solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure white solid intermediate 2 (yield 71%).

[0075] (3) In a 100 mL three-necked round-bottomed reaction flask filled with argon, add N 1 , N 3 - di-p-toluene-1,3-diamine (6.0 mmol), intermediate 2 (15 mmol), Pd 2 (dba) 3 (0.2 mol), Ru-Phos (0.3 mol), t-BuONa (16.0 mmol) and 100 mL of toluene were stirred at 120 ° C for 12 h. The cooled mixture was filtered through diatomaceous earth and washed with dichloromethane. After removing the organic solvent, the residual solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography to obtain a pure white solid intermediate 3 (yield 66%).

[0076] (4) In a 120 mL argon-sealed pressure tube, intermediate 3 (2.0 mmol) and 20 mL dichlorobenzene (o-DCB) were added, followed by boron bromide (22.0 mmol), and the reaction was stirred at 210 °C for 30 h. After cooling to room temperature, ethanol reagent (5.0 mL) was slowly added in an ice bath to quench the reaction. The organic solvent was concentrated under vacuum, and the residual solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) column chromatography to obtain a pure dark yellow solid intermediate 4 (yield 39%).

[0077] (5) In a 120 mL argon sealed pressure tube, add intermediate 4 (1.0 mmol), [1,1'-biphenyl]-2-ylboronic acid (3.5 mol), Pd(PPh 3 )4 (0.15mol), K 2 CO 3 (3.2 mol) and 60 ml of tetrahydrofuran and 15 ml of water were added, and then stirred at 110°C for overnight reaction. Afterwards, the mixture was cooled to room temperature, and the organic solvent was concentrated under vacuum. The residual solid was extracted with dichloromethane and washed with water. The organic solvent was concentrated under vacuum again, and the obtained solid was further separated and purified by silica gel (eluted with petroleum ether / dichloromethane) chromatography column to obtain a pure bright yellow solid product 2 (yield 45%).

[0078] Example 3

[0079] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (3). The difference between the preparation method of embodiment 3 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of [1,1'-biphenyl]-3-boric acid (formula (3')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 60%.

[0080] Figure 1 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 3 in toluene solution (0.01 mM) show that the luminescent peak of the material is in the green light range, the maximum emission wavelength is 518 nm, the full width at half maximum (FWHM) is 15 nm, and it has a narrow half-peak width.

[0081] Example 4

[0082] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (4). The difference between the preparation method of embodiment 4 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of [1,1'-biphenyl]-4-boric acid (formula (4')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 55%.

[0083] Figure 2 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 4 in toluene solution (0.01 mM) show that the luminescent peak of the material is in the green light range, the maximum emission wavelength is 518 nm, the full width at half maximum (FWHM) is 16 nm, and it has a narrow half-peak width.

[0084] Example 5

[0085] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (5). The difference between the preparation method of embodiment 5 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of [1,1':2',1'-triphenyl]-3'-boric acid (formula (5')). The other raw materials and steps are the same as those in embodiment 1. The yield of the solid product finally obtained is 70%.

[0086] Figure 3 The UV-visible absorption spectrum and fluorescence spectrum of the luminescent material of Example 5 in toluene solution (0.01 mM) show that the luminescent peak of the material is in the green light range, the maximum emission wavelength is 518 nm, the full width at half maximum (FWHM) is 14 nm, and the half-peak width is relatively narrow.

[0087] Example 6

[0088] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (6). The difference between the preparation method of Example 6 and that of Example 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of Example 1 is replaced with an equivalent amount of (3,5-difluorophenyl)boric acid (formula (6')). The other raw materials and steps are the same as those in Example 1. The yield of the final solid product is 57%.

[0089] Example 7

[0090] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (7). The difference between the preparation method of Example 7 and that of Example 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of Example 1 is replaced with an equivalent amount of (2-fluorophenyl)boric acid (formula (7')). The other raw materials and steps are the same as those in Example 1. The yield of the final solid product is 63%.

[0091] Example 8

[0092] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (8). The difference between the preparation method of Example 8 and that of Example 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of Example 1 is replaced with an equivalent amount of (3-fluorophenyl)boric acid (formula (8')). The other raw materials and steps are the same as those in Example 1. The yield of the final solid product is 69%.

[0093] Example 9

[0094] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (9). The difference between the preparation method of embodiment 9 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (4-fluorophenyl)boric acid (formula (9')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 62%.

[0095] Example 10

[0096] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (10). The difference between the preparation method of embodiment 10 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (2,3-difluorophenyl)boric acid (formula (10')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 57%.

[0097] Embodiment 11

[0098] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (11). The difference between the preparation method of embodiment 11 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (3,5-dicyanophenyl)boric acid (formula (11')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 49%.

[0099] Example 12

[0100] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (12). The difference between the preparation method of embodiment 12 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (2-cyanophenyl)boric acid (formula (12')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 57%.

[0101] Embodiment 13

[0102] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (13). The difference between the preparation method of embodiment 13 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (3-cyanophenyl)boric acid (formula (13')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 64%.

[0103] Embodiment 14

[0104] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (14). The difference between the preparation method of embodiment 14 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (4-cyanophenyl)boric acid (formula (14')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 75%.

[0105] Embodiment 15

[0106] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in Formula (5). The difference between the preparation method of Example 15 and that of Example 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of Example 1 is replaced with an equivalent amount of (2,3-dicyanophenyl)boric acid (Formula (15')). The other raw materials and steps are the same as those in Example 1. The yield of the final solid product is 71%.

[0107] Example 16

[0108] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (16). The difference between the preparation method of embodiment 16 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (3,5-dichlorophenyl)boric acid (formula (16')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 68%.

[0109] Embodiment 17

[0110] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (17). The difference between the preparation method of embodiment 17 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (2-chlorophenyl)boric acid (formula (17')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 66%.

[0111] Embodiment 18

[0112] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (18). The difference between the preparation method of embodiment 18 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (3-chlorophenyl)boric acid (formula (18')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 69%.

[0113] Embodiment 19

[0114] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (19). The difference between the preparation method of embodiment 19 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (4-chlorophenyl)boric acid (formula (19')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 72%.

[0115] Embodiment 20

[0116] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (20). The difference between the preparation method of embodiment 20 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of (2,3-dichlorophenyl)boric acid (formula (20')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 75%.

[0117] Embodiment 21

[0118] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (21). The difference between the preparation method of embodiment 21 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of pyrimidine-5-boric acid (formula (21')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 67%.

[0119] Embodiment 22

[0120] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (22). The difference between the preparation method of embodiment 22 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of pyridine-2-boric acid (formula (22')), and the other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 64%.

[0121] Embodiment 23

[0122] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (23). The difference between the preparation method of embodiment 23 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of pyridine-3-boric acid (formula (23')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 63%.

[0123] Embodiment 24

[0124] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (24). The difference between the preparation method of embodiment 24 and that of embodiment 1 is that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of pyridin-4-boric acid (formula (24')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 56%.

[0125] Embodiment 25

[0126] The structural formula of the high-efficiency narrow-band luminescent material embedded with dibenzothiophene in this embodiment is shown in formula (25). The preparation method of embodiment 25 is different from that of embodiment 1 in that the [1,1':3',1'-triphenyl]-5'-boric acid in step (5) of the preparation method of embodiment 1 is replaced with an equivalent amount of pyridazine-3-boric acid (formula (25')). The other raw materials and steps are the same as those in embodiment 1. The yield of the final solid product is 71%.

[0127] Application Example 1

[0128] This application embodiment provides an organic electroluminescent device based on an embedded dibenzothiophene high-efficiency narrow-band luminescent material, and its structure is a ternary sensitized OLED structure, specifically: glass substrate / indium tin oxide / HATCN (5 nanometers) / TAPC (30 nanometers) / TCTA (10 nanometers) / mCP (10 nanometers) / luminescent layer (30 nanometers) / TmPyPB (40 nanometers) / lithium fluoride (1 nanometer) / aluminum (150 nanometers). Among them, indium tin oxide is the anode, HATCN is the hole injection layer, TAPC and TCTA are the hole transport layer, mCP is the exciton blocking layer, and the luminescent layer is 2wt% of the luminescent material shown in formula (3): 10wt% tris(2-phenylpyridine)iridium [Ir(ppy) 3]: 88wt% pPhBCzPh, TmPyPB is the electron transport layer, lithium fluoride is the electron injection layer, and aluminum is the cathode. Among them, the structural formulas of HATCN, TAPC, TCTA, mCP, TmPyPB, and PhBCzPh are as follows:

[0129] .

[0130] The preparation method of the organic electroluminescent device is as follows: First, a transparent conductive indium tin oxide (ITO) glass substrate is ultrasonically cleaned for 15 minutes using a micron-sized semiconductor-specific detergent, deionized water, acetone, and isopropanol in sequence to remove dirt on the surface of the substrate. Subsequently, it is placed in a constant temperature oven and dried at 80 degrees Celsius for later use. The dried ITO substrate is treated with oxygen plasma for 5 minutes to further remove organic pollutants attached to the surface. Finally, HATCN, TAPC, TCTA, mCP, the luminescent material shown in formula (3), Ir(ppy) are sequentially deposited by vacuum thermal evaporation. 3 , PhBCzPh, TmPyPB, lithium fluoride and aluminum are deposited to obtain the organic electroluminescent device of this application example.

[0131] Application Example 2

[0132] This application embodiment provides an organic electroluminescent device based on an embedded dibenzothiophene high-efficiency narrow-band luminescent material, and its structure is a ternary sensitized OLED structure, specifically: glass substrate / indium tin oxide / HATCN (6 nanometers) / TAPC (35 nanometers) / TCTA (10 nanometers) / mCP (8 nanometers) / luminescent layer (28 nanometers) / TmPyPB (35 nanometers) / lithium fluoride (1 nanometer) / aluminum (160 nanometers). Among them, indium tin oxide is the anode, HATCN is the hole injection layer, TAPC and TCTA are the hole transport layer, mCP is the exciton blocking layer, and the luminescent layer is 2wt% of the luminescent material shown in formula (4): 8wt% tris(2-phenylpyridine)iridium [Ir(ppy) 3 ]: 90wt% pPhBCzPh, TmPyPB as electron transport layer, lithium fluoride as electron injection layer, and aluminum as cathode.

[0133] The current density-voltage-brightness relationship curve, current efficiency-brightness relationship curve and luminescence spectrum of the organic electroluminescent devices of application examples 1 and 2 are shown in FIG. Figure 4 , Figure 5 and Figure 6 shown.

[0134] Application Example 3

[0135] This application embodiment provides an organic electroluminescent device based on an embedded dibenzothiophene high-efficiency narrow-band luminescent material, and its structure is a ternary sensitized OLED structure, specifically: glass substrate / indium tin oxide / HATCN (5 nanometers) / TAPC (32 nanometers) / TCTA (12 nanometers) / mCP (12 nanometers) / luminescent layer (32 nanometers) / TmPyPB (42 nanometers) / lithium fluoride (1 nanometer) / aluminum (145 nanometers). Among them, indium tin oxide is the anode, HATCN is the hole injection layer, TAPC and TCTA are the hole transport layer, mCP is the exciton blocking layer, and the luminescent layer is 7 wt% of the luminescent material shown in formula (5): 7 wt% tris(2-phenylpyridine)iridium [Ir(ppy) 3 ]: 90wt% pPhBCzPh, TmPyPB as electron transport layer, lithium fluoride as electron injection layer, and aluminum as cathode.

[0136] The various aspects, embodiments, and features of the present invention should be considered to be illustrative in all aspects and not limiting of the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications, and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0137] In the preparation method of the present invention, the order of each step is not limited to the order listed. For those skilled in the art, without creative work, the order of each step is also within the protection scope of the present invention. In addition, two or more steps or actions can be performed simultaneously.

[0138] Finally, it should be noted that the specific embodiments described herein are merely examples of the present invention, and are not intended to limit the implementation methods of the present invention. A person skilled in the art of the present invention may make various modifications or supplements to the specific embodiments described, or replace them in a similar manner. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. A highly efficient narrow-band luminescent material embedded with dibenzothiophene, characterized in that: The luminescent material has a structure shown in the following general formula (I): （I）， Among them, R6 is , , , , or ; R1, R2, R3, R4, and R5 are independently selected from one or more of H, F, Br, Cl, CN, a straight-chain alkyl group having 1 to 30 carbon atoms, a branched-chain alkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic ring consisting of carbon and hydrogen, an aromatic heterocycle consisting of carbon, nitrogen and hydrogen, an aromatic heterocycle consisting of carbon, oxygen and hydrogen, an aromatic heterocycle consisting of carbon, sulfur and hydrogen, and an aromatic heterocycle consisting of carbon, nitrogen, sulfur and hydrogen.

2. The high-efficiency narrow-band luminescent material of endogenous dibenzothiophene according to claim 1, characterized in that: The luminescent material has a structure as shown in any one of the following formulas (1) to (25): 。 3. The high-efficiency narrow-band luminescent material of endogenous dibenzothiophene according to claim 1, characterized in that: The maximum emission wavelength of the luminescent material is 510-520 nm, and the full width at half maximum is ≤20 nm.

4. The method for preparing a high-efficiency narrow-band luminescent material embedded with dibenzothiophene as claimed in claim 1, characterized in that: The following steps are involved: S1, using 2-bromodibenzothiophene as a raw material, a series of CN coupling reactions were performed to synthesize an intermediate 3 having the following structural formula (28); S2 and intermediate 3 are dissolved in a solvent and reacted under the action of a boron halide to generate intermediate 4 shown in the following structural formula (29); S3, intermediate 4 and phenylboronic acid derivatives undergo Suzuki coupling reaction to obtain the final luminescent material; （28）； （29）。 5. The preparation method according to claim 4, characterized in that: Step S1 includes the following steps: S1-1, 2-bromodibenzothiophene and 2,4,6-trimethylaniline react under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain an intermediate 1 having the following structural formula (26): （26）； S1-2, intermediate 1 and 1,3-dibromo-5-chlorobenzene react under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain intermediate 2 having the following structural formula (27): （27）； S1-3, intermediate 2 and N1, N3-di-p-toluene-1, 3-diamine are reacted under conditions including a solvent, a catalyst, a catalyst ligand and a base to obtain intermediate 3.

6. The preparation method according to claim 4, characterized in that: In step S2, the boron halide is one or more of BBr3, BI3 or BCl3; The molar ratio of intermediate 3 to boron halide is 1:1~20; The reaction temperature in step S2 is 180-250° C., and the reaction time is 10-50 h; In step S3, the molar ratio of intermediate 4 to phenylboronic acid derivative is 1:2-10; The temperature of the Suzuki coupling reaction in step S3 is 70-150° C., and the time is 5-50 h.

7. The preparation method according to claim 4, characterized in that: The phenylboronic acid derivative has a structure shown in the following general formula (II): (II), R1, R2, R3, R4, and R5 are independently selected from one or more of H, F, Br, Cl, CN, a straight-chain alkyl group having 1 to 30 carbon atoms, a branched-chain alkyl group having 3 to 30 carbon atoms, a cycloalkyl group having 3 to 30 carbon atoms, an aromatic ring consisting of carbon and hydrogen, an aromatic heterocycle consisting of carbon, nitrogen and hydrogen, an aromatic heterocycle consisting of carbon, oxygen and hydrogen, an aromatic heterocycle consisting of carbon, sulfur and hydrogen, and an aromatic heterocycle consisting of carbon, nitrogen, sulfur and hydrogen.

8. The preparation method according to claim 4 or 7, characterized in that: The phenylboronic acid derivative is a compound represented by any one of formulas (1') to (20'): 。 9. An organic electroluminescent device, characterized in that: The light-emitting layer of the organic electroluminescent device comprises one or more high-efficiency narrow-band light-emitting materials embedded with dibenzothiophene as claimed in claim 1 .

10. The organic electroluminescent device according to claim 9, characterized in that: The organic electroluminescent device comprises an ITO substrate, an anode layer, an organic functional layer and a cathode layer in sequence; wherein the organic functional layer comprises one or more hole injection layers, one or more hole transport layers, one or more light-emitting layers and one or more electron transport layers; the light-emitting layer comprises one or more high-efficiency narrow-band light-emitting materials embedded with dibenzothiophene.

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