Five-substituted pyrene blue organic fluorescent material, preparation method and application thereof

Abstract

The application discloses a kind of five-substituted pyrene blue organic fluorescent materials and preparation method and application, belong to organic electroluminescence technical field.Difference of the activity of pyrene molecule different sites, by the method of gradual introduction, first introduce a substituent group in its 2 number position, then introduce two aryl substituent groups in its 1,3 number position, finally introduce two aryl substituent groups in its 5,9 number position and prepare a kind of five-substituted pyrene organic fluorescent material.By introducing different substituent groups in the 1,2,3,5,9 number position of pyrene molecule, on the one hand, the π conjugated form of organic molecule, intramolecular charge transfer path, molecular dipole horizontal orientation, etc., realize the modulation of organic molecule's luminescence color and the balance of carrier injection in OLED device application;On the other hand, effectively inhibit the π-π stacking interaction between molecules, inhibit the red shift of spectrum, improve the luminescence quantum efficiency of organic material molecule.

Description

Technical Field

[0001] This invention belongs to the field of organic electroluminescence technology, specifically relating to a pentasubstituted pyrene-based blue organic fluorescent material, its preparation method, and its application. Background Technology

[0002] Organic light-emitting diodes (OLEDs) possess advantages such as flat light emission, fast response speed, large area, and good flexibility, and are now widely used in everyday lighting and flat panel displays. Currently, the mainstream commercial red and green light-emitting materials are phosphorescent materials, which almost meet commercial requirements in terms of efficiency and stability. However, blue phosphorescent materials, due to high cost, poor color purity, complex device manufacturing processes, and severe roll-off at high brightness, do not meet commercial standards. Therefore, current commercial blue light materials use first-generation traditional fluorescent materials, which have lower efficiency and brightness, typically requiring layering processes to compensate. Thus, a new generation of high-efficiency and high-stability blue OLED materials is a recent focus in this field.

[0003] According to spin statistics theory, only 25% of singlet excitons can be utilized in traditional organic fluorescent materials, while the remaining 75% of triplet excitons are wasted through nonradiative transitions, resulting in poor electroluminescence performance. To overcome the limitations of spin statistics and maximize the utilization of excitons, next-generation high-efficiency fluorescent materials such as triplet-triplet annihilation (TTA), thermally activated delayed fluorescence (TADF), and "thermal exciton" materials have been extensively studied. Among these, TTA materials have gained widespread commercial application due to their excellent device stability, long lifetime, and low efficiency roll-off.

[0004] Common TTA-type blue fluorescent materials mainly consist of rigid conjugated molecules such as anthracene and pyrene as their cores. These materials typically exhibit high fluorescence quantum yields and stability. Pyrene, as a cyclic fused polycyclic aromatic hydrocarbon (PAH), possesses both electron-donating and electron-withdrawing properties. It displays strong blue fluorescence and good quantum yield in solution, resulting in excellent optical properties. Furthermore, it demonstrates solution-processability, good thermal stability, high charge carrier mobility, and high luminous efficiency in organic electroluminescent devices. However, due to the large rigid planar conjugated structure of pyrene molecules, they readily undergo π-π stacking in the solid state to form excitopolymers, leading to aggregation fluorescence quenching, a redshift in the electroluminescence spectrum, and a decrease in device efficiency, thus limiting its application in OLEDs. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a pentasubstituted pyrene-based blue organic fluorescent material, its preparation method and application, so as to solve the problems that planar pyrene-based blue organic fluorescent materials in the prior art are prone to accumulation in the light-emitting layer, which further causes red shift of the electroluminescence spectrum and decrease in device efficiency.

[0006] To achieve the above objectives, the present invention employs the following technical solution:

[0007] A pentasubstituted pyrene-based blue organic fluorescent material, with the following structural formula:

[0008]

[0009] R1 to R5 are selected from any one of hydroxyl, alcohol hydroxyl, alkyl, deuterated alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted fused-ring aryl, substituted or unsubstituted heterofused-ring aryl, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, substituted or unsubstituted heterofused-ring arylamine, substituted or unsubstituted fused-ring arylamine, and substituted or unsubstituted fused-ring arylamine, and R1 to R5 are not hydrogen.

[0010] A further improvement of the present invention is that:

[0011] Preferably, R1 is selected from any one of hydroxyl, alcohol hydroxyl, C1-C6 alkyl, C1-C6 deuterated alkyl, C1-C6 alkoxy, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, and substituted or unsubstituted C2-C30 heterofused-ring aryl, and R1 is not hydrogen.

[0012] Preferably, R2 to R5 are selected from any one of substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted fused-ring aryl, substituted or unsubstituted heterofused-ring aryl, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, substituted or unsubstituted fused-ring arylamine, and substituted or unsubstituted heterofused-ring arylamine, having 2 to 60 carbon atoms, and R2 to R5 are not hydrogen.

[0013] Preferably, R1 to R5 are any one of the following formulas:

[0014]

[0015]

[0016]

[0017] Wherein, X is the same or different from BR, CRR, NR, O, S; CRR indicates that two R groups are attached to the C atom; R is independently selected from one of H, D, F, CN, or R represents any one of hydroxyl, trifluoromethyl, methoxy, aldehyde, C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, or substituted or unsubstituted C2-C30 heterofused-ring aryl;

[0018] The substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, and substituted or unsubstituted C2-C30 heterofused-ring aryl are independently selected from one of the following: phenyl, naphthyl, anthracene, phenanthryl, diphenyl, terphenyl, fluorenyl, pyridyl, carbazole, furanyl, pyrimidinyl, pyrazinyl, pyridazinyl, thiophene, benzothiophene, benzofuranyl, dibenzothiophene, dibenzofuranyl, oxazolyl, carbazole;

[0019] n can be 0, 1, 2, 3, or 4;

[0020] The heteroaryl group refers to a heteroatom containing at least one of B, N, O, or S, with * indicating a position connected to an adjacent atom.

[0021] Preferably, R1 to R5 are any one of the following formulas:

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] * indicates a position connected to an adjacent atom.

[0032] Preferably, R1 is

[0033] Any one of them.

[0034] Preferably, R2 is

[0035]

[0036] R3 is

[0037]

[0038] Preferably, R4 is

[0039]

[0040] Any one of them;

[0041] R5 is

[0042]

[0043] Any one of them.

[0044] A method for preparing the above-mentioned pentasubstituted pyrene-based blue organic fluorescent material: pyrene is subjected to a boronization reaction of tert-butyl and CH bonds to obtain intermediate 2; intermediate 2 is subjected to a C-C bonding reaction or a CN bonding reaction to obtain intermediate 3 with an R1 substituent; intermediate 3 is subjected to a halogenation reaction to obtain intermediate 5; intermediate 5 is subjected to a C-C bonding reaction or a CN bonding reaction to obtain intermediate 6 with R2 and R3 substituents; intermediate 6 is subjected to a halogenation reaction to obtain intermediate 7; and intermediate 7 is subjected to a C-C or CN bonding reaction to obtain the pentasubstituted pyrene-based blue organic fluorescent material.

[0045] The process of obtaining intermediate 5 from intermediate 2 can also be further modified by halogenation of intermediate 2 to obtain intermediate 4, and intermediate 4 can be further modified by hydroxylation to obtain intermediate 5.

[0046] An application of the above-mentioned pentasubstituted pyrene-based blue organic fluorescent material, wherein the pentasubstituted pyrene-based blue organic fluorescent material is used to prepare organic electroluminescent devices;

[0047] The organic electroluminescent device includes an anode, a cathode disposed on a substrate, and an organic functional layer disposed between the anode and the cathode. The light-emitting layer in the organic functional layer includes at least one pentasubstituted pyrene-based blue organic fluorescent material as described in any one of claims 1 to 8.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention discloses a pentasubstituted pyrene-based blue organic fluorescent material. This pentasubstituted pyrene-based blue organic fluorescent material has a non-planar rigid structure and is a type of organic light-emitting material with a blue emission peak and high quantum efficiency, which can be used to fabricate organic electroluminescent devices. By introducing different substituent groups at positions 1, 2, 3, 5, and 9 of the pyrene molecule, this organic fluorescent material can, on the one hand, regulate the π-conjugated morphology of the organic molecule, the intramolecular charge transfer path, and the horizontal orientation of the molecular dipole, achieving a balance between the emission color modulation of the organic molecule and the carrier injection in OLED device applications; on the other hand, it effectively suppresses the π-π stacking interactions between molecules, suppresses the spectral redshift, and improves the emission quantum efficiency of the organic material molecules. Therefore, applying this pyrene-based blue organic fluorescent material as a light-emitting material in doped blue OLED devices yields devices with a series of advantages, including high external quantum efficiency and good color purity.

[0050] This invention discloses a method for preparing a pentasubstituted pyrene-based blue organic fluorescent material. By utilizing the difference in activity at different sites of the pyrene molecule, a stepwise introduction method is used to first introduce a substituent group at position 2, then introduce two aryl substituent groups at positions 1 and 3, and finally introduce two aryl substituent groups at positions 5 and 9 to prepare a pentasubstituted pyrene-based organic fluorescent material.

[0051] The present invention also discloses the application of a pentasubstituted pyrene-based blue organic fluorescent material, which is used as a guest material in doped OLED devices. The devices prepared have a series of advantages such as a blue electroluminescence peak, high external quantum efficiency, and high color purity. Attached Figure Description

[0052] Figure 1 This is a schematic diagram of the structure of two organic electroluminescent devices (A and B) used in this invention.

[0053] Figure 2 It is the target compound TC-33 1 H NMR spectrum.

[0054] Figure 3 It is the target compound TC-34 1 H NMR spectrum.

[0055] Figure 4 It is the target compound TC-41 1 H NMR spectrum.

[0056] Figure 5 It is the target compound TC-58 1 H NMR spectrum.

[0057] Figure 6 It is the target compound TC-61 1H NMR spectrum.

[0058] Figure 7 It is the target compound TC-169 1 H NMR spectrum.

[0059] Figure 8 It is the target compound TC-180 1 H NMR spectrum.

[0060] Figure 9 It is the target compound TC-207 1 H NMR spectrum.

[0061] Figure 10 It is the target compound TC-217 1 H NMR spectrum.

[0062] Figure 11 It is the target compound TC-230 1 H NMR spectrum.

[0063] Figure 12 It is the target compound TC-231 1 H NMR spectrum.

[0064] Figure 13 It is the target compound TC-446 1 H NMR spectrum. Detailed Implementation

[0065] The present invention will now be described in further detail with reference to the accompanying drawings:

[0066] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0067] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0068] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0069] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0070] The first aspect of this invention discloses a pentasubstituted pyrene-based blue organic fluorescent material, the structural formula of which is as follows:

[0071]

[0072] In the above structural formulas, R1 to R5 are selected from hydroxyl, alcohol hydroxyl, alkyl, deuterated alkyl, alkoxy, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted fused-ring aryl, substituted or unsubstituted heterofused-ring aryl, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, substituted or unsubstituted heterofused-ring arylamine, substituted or unsubstituted fused-ring arylamine, and combinations thereof, and R1 to R5 are not hydrogen.

[0073] In the organic compound structural formula of the present invention, R1 is preferably any one of hydroxyl, alcohol hydroxyl, C1-C6 alkyl, C1-C6 deuterated alkyl, C1-C6 alkoxy, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, or substituted or unsubstituted C2-C30 heterofused-ring aryl, and R1 is not hydrogen.

[0074] R2 to R5 are preferably any one of the following: substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted fused-ring aryl, substituted or unsubstituted heterofused-ring aryl, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, substituted or unsubstituted fused-ring arylamine, substituted or unsubstituted heterofused-ring arylamine, substituted or unsubstituted heterofused-ring arylamine, and substituted or unsubstituted heterofused-ring arylamine, having 2 to 60 carbon atoms, and R2 to R5 are not hydrogen.

[0075] In this invention, the term "substituted or unsubstituted" means that the functional group described after the term may or may not have a substituent R. For example, "substituted or unsubstituted aryl" refers to an aryl group having a substituent R or an unsubstituted aryl group. The substituent R can be, for example, a hydroxyl group, an alcohol hydroxyl group, an alkyl group, a deuterated alkyl group, an alkoxy group, an aryl group, a heteroaryl group, a fused-ring aryl group, an arylamine group, a heteroarylamine group, a fused-ring arylamine group, or a fused-ring arylamine group; the number of substituents can be one or more.

[0076] In this invention, "multiple" refers to two or more, such as two, three, four, five, six, etc.

[0077] In some embodiments of the present invention, the structural formulas R1 to R5 are represented by the following representative structures:

[0078]

[0079]

[0080]

[0081] Wherein, X is the same or different from BR, CRR, NR, O, S; CRR indicates that two R groups are attached to the C atom; R is independently selected from one of H, D, F, CN, or R represents any one of hydroxyl, trifluoromethyl, methoxy, aldehyde, C1-C6 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, or substituted or unsubstituted C2-C30 heterofused-ring aryl;

[0082] The substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C2-C30 heteroaryl, substituted or unsubstituted C2-C30 fused-ring aryl, and substituted or unsubstituted C2-C30 heterofused-ring aryl are independently selected from one of the following: phenyl, naphthyl, anthracene, phenanthryl, diphenyl, terphenyl, fluorenyl, pyridyl, carbazole, furanyl, pyrimidinyl, pyrazinyl, pyridazinyl, thiophene, benzothiophene, benzofuranyl, dibenzothiophene, dibenzofuranyl, oxazolyl, carbazole; n is 0, 1, 2, 3, or 4; the aforementioned heteroaryl refers to a heteroatom containing at least one of B, N, O, or S, and * indicates a position connected to an adjacent atom.

[0083] In some embodiments of the present invention, one or more of the following representative structures are used to independently represent R1 to R5 in the structural formula of claim 1:

[0084]

[0085]

[0086]

[0087]

[0088]

[0089]

[0090]

[0091]

[0092]

[0093] * indicates a position connected to an adjacent atom.

[0094] Furthermore, based on the above structural formula, the structural formula of the pentasubstituted pyrene-based blue organic fluorescent material is represented by any one of the structural formulas in the table below.

[0095] Table 1. Structural formulas of pentasubstituted pyrene-based blue organic fluorescent materials

[0096]

[0097]

[0098]

[0099]

[0100]

[0101] In some embodiments of the present invention, R1 is

[0102] Any one of them. In some embodiments of the present invention, R2 is

[0103]

[0104] R3 is

[0105]

[0106] In some embodiments of the present invention, R4 is

[0107]

[0108] Any one of them;

[0109] R5 is

[0110]

[0111] Any one of them.

[0112] The second aspect of this invention discloses a method for preparing a pentasubstituted pyrene-based blue organic fluorescent material. The compound involved in this invention can be synthesized through the following reaction pathway: starting with pyrene, intermediate 2 can be obtained through a simple tert-butyl substitution reaction and a CH bond borlation reaction. Intermediate 2 can be obtained as an intermediate with R1 substitution through a CC or CN bonding reaction under suitable conditions. Then, intermediate 5 can be obtained through a halogenation reaction such as bromination. Alternatively, intermediate 4 can be obtained from intermediate 2 through a halogenation reaction such as bromination. Then, intermediate 5 can be obtained through a hydroxylation reaction under suitable conditions (this process is mainly used to synthesize intermediate 5 with hydroxyl, alkyl hydroxyl, and alkyl groups at the 2-position). Then, intermediate 5 can be reacted with a suitable raw material under certain conditions through a CC or CN bonding reaction to obtain intermediate 6 with R2 and R3 substitution. Then, intermediate 7 can be obtained through a halogenation reaction such as bromination. Finally, the target compound molecule involved in this invention can be obtained through a CC or CN bonding reaction under suitable conditions.

[0113]

[0114] The specific preparation method includes the following steps:

[0115] (1) According to the method reported in the literature (RSC Adv., 2015, 5, 8835–8848; Chem. Commun., 2005, 2172-2174), the raw material pyrene was subjected to tert-butyl substitution and borate esterification in sequence to obtain intermediate 2.

[0116] (2) Under nitrogen protection, 3.8 g of intermediate 2 and 2.6 g of iodobenzene were completely dissolved in 75 mL of toluene in a round-bottom flask. Then, 25 mL of potassium carbonate aqueous solution (2M), 25 mL of ethanol and 350 mg of tetrakis(triphenylphosphine)palladium were added. The mixture was heated to 110 °C and stirred for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, and the organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried over anhydrous sodium sulfate and the dichloromethane was removed by vacuum distillation. The crude product was eluented with petroleum ether and subjected to silica gel column chromatography to give intermediate 3-1 (2.9 g), with a yield of 86%.

[0117]

[0118] By replacing the iodobenzene in step (2) with boric acid or borate esters of other groups, the following intermediates 3-2 (3.2 g) and 3-3 (3.1 g) can be obtained, with yields of 83% and 55%, respectively.

[0119]

[0120] (3) Under nitrogen protection, 5 g of intermediate 3-1 and 5 g of N-bromosuccinimide were dissolved in 100 mL of tetrahydrofuran in a round-bottom flask. The mixture was stirred and reacted at room temperature for 12 hours. After the reaction was completed, 10% sodium thiosulfate solution was added to neutralize the mixture. The organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate and dichloromethane was removed by vacuum distillation. The crude product was then subjected to silica gel column chromatography with petroleum ether:dichloromethane (10:1) as the eluent to obtain intermediate 5-1 (4.2 g), with a yield of 60%.

[0121]

[0122] By replacing intermediate 3-1 with intermediate 3-2 in step (3), the following intermediate 5-2 (3.3g) can be obtained with a yield of 73%.

[0123]

[0124] (4) Under nitrogen protection, 2.1 g of intermediate 3-3, 2.3 g of N-bromosuccinimide, 890 mg of cuprous bromide and 0.2 mL of acetic acid were dissolved in 40 mL of dichloroethane in a round-bottom flask. The mixture was heated to 100 °C and stirred for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and the organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate and the crude product was obtained by vacuum distillation. The crude product was obtained by silica gel column chromatography using dichloromethane as the eluent, and the yield of intermediate 5-3 (2.0 g) was obtained, with a yield of 65%.

[0125]

[0126] (5) Under nitrogen protection, 4.8 g of intermediate 2 and 4.7 g of N-bromosuccinimide were dissolved in 100 mL of tetrahydrofuran in a round-bottom flask. The mixture was stirred at room temperature for 12 hours. After the reaction was completed, 10% sodium thiosulfate solution was added to neutralize the mixture. The organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate and the crude product was obtained by vacuum distillation. The crude product was obtained by silica gel column chromatography with petroleum ether:dichloromethane (5:1) as the eluent to give intermediate 4 (5.0 g) with a yield of 74%.

[0127]

[0128] (6) Under nitrogen protection, 3.9 g of intermediate 4 and 0.7 g of sodium hydroxide were added to 280 mL of tetrahydrofuran and stirred for 10 minutes. Then, 2 mL of hydrogen peroxide solution (30%) and 4 mL of water were added to the mixture, and the mixture was stirred at room temperature for 4 hours. The pH of the mixture was then adjusted to 1-2 using 1 M hydrochloric acid solution. The mixture was then washed repeatedly under reduced pressure with water, methanol, and n-hexane to obtain intermediate 5-4 (2.8 g), with a yield of 90%.

[0129]

[0130] (7) Under nitrogen protection, 2.1 g of intermediate 5-1 and 3.1 g of 4-tert-butylphenylboronic acid were completely dissolved in 80 mL of toluene in a round-bottom flask. Then, 20 mL of potassium carbonate aqueous solution (2M), 20 mL of ethanol and 250 mg of tetrakis(triphenylphosphine)palladium were added. The mixture was heated to 110 °C and stirred for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, and the organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried over anhydrous sodium sulfate and the dichloromethane was removed by vacuum distillation. The crude product was eluented with petroleum ether and subjected to silica gel column chromatography to give intermediate 6-1 (1.3 g), with a yield of 50%.

[0131]

[0132] By replacing intermediate 5-1 with intermediate 5-2 to intermediate 5-4, or replacing 4-tert-butylphenylboronic acid with other boric acids or borate esters, intermediates 6-2 to 6-6 can be obtained in yields of 45% to 73%.

[0133]

[0134] (8) Under nitrogen protection, 1.2 g of intermediate 6-1 was dissolved in 40 mL of dichloromethane in a round-bottom flask. Then, a mixture of 0.2 mL of liquid bromine and 5 mL of dichloromethane was added dropwise at -75 °C. After stirring for 30 minutes at this low temperature, the reaction apparatus was moved to room temperature and reacted for 12 hours. After the reaction was completed, 10% sodium thiosulfate solution was added for neutralization, and the organic solvent was removed by vacuum distillation. The product was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate and the dichloromethane was removed by vacuum distillation. The crude product was then subjected to silica gel column chromatography with petroleum ether:dichloromethane (10:1) as the eluent to obtain intermediate 7-1 (1.22 g), with a yield of 78%.

[0135]

[0136] By replacing intermediate 6-1 with intermediate 6-2 to intermediate 6-6 in step (8) and controlling the amount of liquid bromine, intermediates 7-2 to 7-6 can be obtained with a yield of 45% to 73%.

[0137]

[0138] A third aspect of the present invention discloses an application of a pentasubstituted pyrene-based blue organic fluorescent material, which is used to prepare two types of organic electroluminescent devices. The two types of organic electroluminescent devices include an anode and a cathode disposed on a substrate, and an organic functional layer disposed between the anode and the cathode, wherein at least one of the organic functional layers comprises any one of the aforementioned pentasubstituted pyrene-based blue organic fluorescent materials.

[0139] Furthermore, all substrates are made of glass, all anodes are made of conductive glass substrates, and all cathodes are made of aluminum electrodes; the organic functional layer includes a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer, or a combination thereof.

[0140] The luminescent layer uses any one of the aforementioned pentasubstituted pyrene-based blue organic fluorescent materials as the guest material or the host material.

[0141] Preferably, the luminescent layer comprises a composition formed by any of the above-mentioned pentasubstituted pyrene-based blue organic fluorescent materials as guest materials and one or more host materials.

[0142] The following description, in conjunction with specific embodiments, provides further details.

[0143]

Synthesis of Examples

[0144] (1) Using intermediate 7-2 as a raw material, under nitrogen protection, 1.5 g of intermediate 7-2 and 1.1 g of phenylboronic acid were completely dissolved in 80 mL of toluene in a round-bottom flask. Then, 20 mL of potassium carbonate aqueous solution (2M), 20 mL of ethanol and 250 mg of tetra(triphenylphosphine)palladium were added. The mixture was heated to 110 °C and stirred for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, and the organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate, and the dichloromethane was removed by vacuum distillation. The crude product was eluented with petroleum ether, and then subjected to silica gel column chromatography. After recrystallization, the target compound TC-6 (880 mg) was obtained, with a yield of 60%.

[0145]

[0146] (2) Using other intermediates 7-3 to 7-6 as raw materials, and selecting appropriate boric acid groups, the synthesis steps are the same as in (1) to obtain the target compounds TC-33, TC-34, TC-58, TC-217 and TC-446, with yields of 53% to 86%.

[0147]

[0148] (3) Using intermediate 7-1 as a raw material, under nitrogen protection, 1.2 g of intermediate 7-1, 1.1 g of diphenylamine, and 780 mg of sodium tert-butoxide were completely dissolved in 80 mL of toluene in a round-bottom flask. Then, 180 mg of palladium acetate and 2.1 mL of tritert-butylphosphine were added sequentially. The mixture was heated to 110 °C and stirred for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, and the organic solvent was removed by vacuum distillation. The mixture was extracted with dichloromethane and saturated brine. The organic phase was dried with anhydrous sodium sulfate and the dichloromethane was removed by vacuum distillation. The crude product was subjected to silica gel column chromatography with petroleum ether:dichloromethane (10:1) as the eluent, and then recrystallized to obtain the target compound TC-207 (960 mg), with a yield of 64%.

[0149]

[0150] (4) Using other intermediates 7-2 to 7-6 as raw materials, select appropriate aromatic amine groups and synthesize them in the same way as (1) to obtain target compounds TC-41, TC-61, TC180, TC-230 and TC-231 with yields of 30% to 67%.

[0151]

[0152] The structural characterization of the target compounds obtained in the above preparation examples is shown in the table below:

[0153] Table 2 Characterization of the target compounds

[0154]

[0155]

[0156]

[0157] To make the objectives, technical solutions, and advantages of this invention clearer, the application effects of the pyrene-based blue organic fluorescent material in the devices are described in detail below through device examples 1-12 and device comparative examples 1-4. This invention employs two device structures. Device examples 2-6, comparative examples 1, and 2 have the same fabrication process as device example 1. Device examples 8-12, comparative examples 3, and 4 have the same fabrication process as device example 7. Furthermore, the same substrate material and electrode material are used, and the electrode film thickness remains consistent. The only difference is the replacement of the light-emitting layer material in the device. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0158] As attached Figure 1 As shown in Figure (a), the first blue organic electroluminescent device A provided by the present invention is composed of a substrate 1, an anode layer 2, a hole injection layer 3, a hole transport layer 4, an electron blocking layer 5, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a metal cathode 9, connected in sequence; wherein the substrate 1 is a glass substrate; the anode layer 2 is made of ITO (indium tin oxide), and the surface resistance of the indium tin oxide layer is 15-20 Ω / sq; the hole injection layer 3 is made of 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazabenzophenanthrene, abbreviated as (HAT-CN); the hole transport layer 4 is made of 4,4'-cyclohexyldi[N,N-di(4-methyl)] The electron blocking layer 5 is 4,4',4'-tris(carbazol-9-yl)triphenylamine, abbreviated as (TAPC); the electron blocking layer 6 is 1,3-dicarbazolylphenyl, abbreviated as (mCP), which is used as the main material and doped with six blue fluorescent materials, TC-33, TC-34, TC-58, TC-169, TC-217, and TC-446, at a mass fraction of 94:6; the electron transport layer 7 is 1,3,5-tris(3-pyridyl-3-phenyl), abbreviated as (TmPyPB); the electron injection layer is LiF8; and the metal cathode 9 is high-purity metallic Al.

[0159] As attached Figure 1As shown in Figure (b), the second type of blue organic electroluminescent device B provided by the present invention is composed of a substrate 1, an anode layer 2, a hole injection layer 3, a hole transport layer 4, a light-emitting layer 6, an electron transport layer 7, an electron injection layer 8, and a metal cathode 9, connected in sequence; wherein the substrate 1 is a glass substrate; the anode layer 2 is made of ITO (indium tin oxide), and the surface resistance of the indium tin oxide layer is 15-20 Ω / sq; the hole injection layer 3 is made of 4,4',4'-tris[2-naphthylphenylamino]triphenylamine, abbreviated as (2T-NATA); the hole transport layer 4 is made of N,N'-di(1-naphthyl)-N,N The light-emitting layer 6 uses '-diphenyl-4,4'-biphenyldiamine, abbreviated as (NPB); the light-emitting layer 6 uses 9-(1-naphthyl)-10-(2-naphthyl)anthracene, abbreviated as (α,β-ADN), as the main material and is doped with five blue fluorescent materials, TC-41, TC-61, TC180, TC-207, and TC-230, at a mass fraction of 96:4; the electron transport layer 7 uses 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene, abbreviated as (TPBi); the electron injection layer 8 uses LiF; and the metal cathode 9 uses high-purity metallic Al.

[0160] The technical effects of the compounds of the present invention will be explained in more detail below through device examples.

[0161]

Preparation of Device Example 1

[0162] Adopting attachment Figure 1 The structure of device A involves first chemically etching the ITO layer on the ITO glass substrate into thin strips 10 mm wide and 30 mm long, then ultrasonically cleaning it with detergent and deionized water for 30 minutes, followed by ultrasonic cleaning with acetone and isopropanol for 30 minutes each, drying it at 75°C, and then performing ultraviolet-ozone cleaning to remove organic residues from the transparent ITO surface.

[0163] The glass substrate with the anode was placed in a vacuum chamber, and a vacuum evaporation device was used to evaporate it until the vacuum level reached 4 × 10⁻⁶. -4Below Pa, in sequence, a 5 nm thick HAT-CN layer as a hole injection layer 3 is deposited on the ITO anode layer 2 at a deposition rate controlled at 0.05 nm / s; a 30 nm thick TAPC layer as a hole transport layer 4 is deposited at a deposition rate controlled at 0.1 nm / s; a 5 nm thick TCTA layer as an electron blocking layer 5 is deposited at a deposition rate controlled at 0.05 nm / s; and a 20 nm thick light-emitting layer 6 with a mCP to TC-33 mass ratio of 94:6 is deposited, with the deposition rate of the main material mCP controlled at 0.0 nm / s. The evaporation rate of the guest material TC-33 was set to 0.006 nm / s at a ratio of 4%; a 30 nm thick TmPyPB layer was used as the electron transport layer 7, with an evaporation rate controlled at 0.1 nm / s; it was then transferred to a metal evaporation chamber, where a 1 nm thick LiF layer was first deposited as the electron injection layer 8, followed by a 100 nm aluminum electrode layer, which served as the cathode layer 9. The evaporation rates of LiF and Al were controlled at 0.05 nm / s and 0.3 nm / s, respectively. Finally, an organic electroluminescent device with the structure ITO / HAT-CN (5 nm) / TAPC (30 nm) / TCTA (5 nm) / mCP:TC-33 = 94:6 (20 nm) / TmPyPB (30 nm) / LiF (1 nm) / Al (100 nm) was fabricated.

[0164]

Preparation of Device Example 7

[0165] Adopting attachment Figure 1 The structure of device B involves cleaning the ITO glass substrate in the same way as in device embodiment 1. The cleaned glass substrate with the anode is placed in a vacuum chamber, and a vacuum evaporation apparatus is used until the vacuum level reaches 4 × 10⁻⁶. -4Below Pa, in sequence, a 30 nm thick 2T-NATA layer is deposited on the ITO anode layer 2 as a hole injection layer 3, with the deposition rate controlled at 0.1 nm / s; a 30 nm thick NPB layer is deposited as a hole transport layer 4, with the deposition rate controlled at 0.1 nm / s; a 25 nm thick luminescent layer 6 is formed with a mass ratio of α,β-ADN and TC-41 of 96:4, with the deposition rate of the host material α,β-ADN controlled at 0.096 nm / s and the deposition rate of the guest material TC-41 set at 0.004 nm / s according to a 4% ratio; a 30 nm thick TPBi layer is deposited as an electron transport layer 7, with the deposition rate controlled at 0.1 nm / s; then it is transferred to a metal deposition chamber, where a 1 nm thick LiF layer is deposited first as an electron injection layer 8, followed by a 100 nm thick aluminum electrode layer, which is used as metal 9, with the deposition rates of LiF and Al controlled at 0.05 nm / s and 0.3 nm / s, respectively. The final organic electroluminescent device was fabricated with the structure ITO / 2T-NATA(30nm) / NPB(30nm) / α,β-ADN:TC-41=96:4(25nm) / TPBi(30nm) / LiF(1nm) / Al(100nm).

[0166] The preparation steps of the other embodiments are the same as those of the two embodiments described above, except that the guest material in the light-emitting layer is replaced with the other compounds in the embodiments instead of TC-33 and TC-41. The results are shown in the table below.

[0167] The molecular structure of the relevant luminescent layer material is shown below:

[0168]

[0169]

[0170] Comparative Example 1 and Comparative Example 2

[0171] The fabrication steps are the same as in the above embodiments, and the device structure is the same or similar. The guest material in the light-emitting layer is the reported material Py-BBz, Py-B2An, Py(5,9)BDPA and Py(5,9)BMTBA, which are shown in the following figures:

[0172]

[0173] The device structures of the fabricated embodiments and comparative examples are shown in the table below:

[0174] Table 3 Device Structure

[0175]

[0176]

[0177] The fabricated devices were tested using a Keithley system. The performance comparison results of Comparative Examples 1, 2, 3, and 4 with those of Examples 1 to 12 are shown in the table below:

[0178] Table 4 Comparative Examples and Device Performance of Devices in the Examples

[0179]

[0180]

[0181] The above results indicate that the pentasubstituted pyrene-based blue organic fluorescent materials of the present invention, when applied to electroluminescent devices, exhibit a bluer emission peak compared to Comparative Examples 1 and 2, and the same or even higher luminance compared to Comparative Example 1. Specifically, the y-values ​​of the color coordinates in Examples 4 and 6 are significantly reduced. Compared to Comparative Examples 3 and 4, Examples 7-12, in addition to having a bluer emission peak, also exhibit a higher maximum external quantum efficiency (EQE). max This material also exhibits a narrower half-width at half-maximum (WHM) and a smaller chromaticity (y-coordinate), resulting in better color purity. This technique leverages the differences in activity at different sites within the pyrene molecule. A pentasubstituted pyrene-based blue organic fluorescent material is prepared by progressively introducing a substituent group at position 2, followed by two aryl substituent groups at positions 1 and 3, and finally two more aryl substituent groups at positions 5 and 9. By introducing different substituent groups at positions 1, 2, 3, 5, and 9 of the pyrene molecule, the π-conjugated morphology, intramolecular charge transfer pathways, and molecular dipole orientation of the organic molecule can be controlled, achieving a balance between the emission color modulation of the organic molecule and carrier injection in OLED device applications. Furthermore, it effectively suppresses intermolecular π-π stacking interactions, inhibiting spectral redshift. Applying this type of luminescent material as a guest material in doped blue OLED devices results in a blue shift in the electroluminescence spectrum of the prepared devices, and improves the external quantum efficiency and color purity.

[0182] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A pentasubstituted pyrene-based blue organic fluorescent material, characterized in that, The structural formula is: R1 is , , or Any one of them; R2 is or ; R3 is or ; R4 is 、 、 、 、 、 、 or Any one of them; R5 is 、 、 、 、 、 、 or Any one of them.

2. A method for preparing the pentasubstituted pyrene-based blue organic fluorescent material according to claim 1, characterized in that, The roadmap for the preparation method is as follows: 。 3. An application of the pentasubstituted pyrene-based blue organic fluorescent material according to claim 1, characterized in that, The pentasubstituted pyrene-based blue organic fluorescent material is used to prepare organic electroluminescent devices; The organic electroluminescent device includes an anode, a cathode disposed on a substrate, and an organic functional layer disposed between the anode and the cathode. The light-emitting layer in the organic functional layer includes at least one of the pentasubstituted pyrene-based blue organic fluorescent materials as described in claim 1 as a guest material.

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