A novel bisboron compound and applications thereof, and an organic electroluminescent device comprising the same

Abstract

This invention discloses a fused heterocyclic compound for use in organic electroluminescent devices. The compound is represented by general formula (1), general formula (2), or general formula (3), and its molecular skeleton contains two boron atoms. These boron atoms participate in the formation of a fused aromatic skeleton through boron-carbon bonds and boron-nitrogen covalent bonds, respectively. This invention also discloses an organic electroluminescent device comprising an anode, a cathode, and at least one organic thin film located between them. The organic thin film contains the aforementioned compound, which is used as a light-emitting guest material in the device. Compared to the monoboron-nitrogen structure, the diboron-nitrogen structure of this invention has a shorter delayed fluorescence lifetime, which can weaken triplet exciton quenching, thereby suppressing efficiency roll-off and improving device efficiency and lifetime. The covalent bonding of boron and nitrogen enhances the planarity of the skeleton and weakens high-frequency stretching, narrowing the spectrum and improving efficiency. Modification with R groups on the molecular periphery increases steric hindrance and reduces aggregation, further improving the stability of the light-emitting device.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescence technology, and particularly to a novel bisboron compound and its applications, as well as an organic electroluminescent device comprising the bisboron compound. Background Technology

[0002] Display panels composed of organic light-emitting diodes (OLEDs) offer advantages such as low power consumption, wide color gamut, and high brightness; after decades of technological iteration, their commercial applications have become increasingly widespread. Phosphorescence or thermally induced delayed fluorescence sensitization (PSF or TSF) can significantly improve device efficiency and reduce power consumption, thereby extending product lifespan. Green light using PSF technology is already in mass production and use in products.

[0003] PSF technology consists of a host, a sensitizer, and a guest element forming the luminescent layer. While the host and sensitizer can utilize existing materials, the guest element requires redevelopment and continuous iteration, and is a key factor limiting efficiency and lifetime. Current guest element materials are boron-nitrogen materials with narrow spectral characteristics (Hatakeyama et al.). Advanced Materials (2016, 28(14): 2777–2781). Due to the weak electronic properties of boron and nitrogen atoms, boron-nitrogen materials exhibit multiple resonances throughout the molecule. This not only makes the HOMO / LUMO electron cloud distribution more uniform but also significantly suppresses non-radiative vibrations of the molecule, resulting in a very narrow full width at half maximum (FWHM) and low shoulder peaks in the overall molecule's spectrum. Compared to the monoboron-nitrogen structure, the diboron-nitrogen structure has a shorter delayed fluorescence lifetime, thereby reducing the quenching of triplet excitons and effectively suppressing efficiency roll-off, improving device efficiency and device lifetime. Summary of the Invention

[0004] This invention mainly designs a high-efficiency, long-lifetime fluorescent luminescent material based on a boron-nitrogen structure; one boron-nitrogen structure forms a boron-carbon bond, and the other boron-nitrogen structure forms both a boron-carbon bond and a boron-nitrogen covalent bond; at the same time, the outer structure of the molecule is modified by different functional groups to increase the rigidity and stability of the molecule.

[0005] 1) A fused heterocyclic compound for use in organic electroluminescent devices, wherein the fused heterocyclic compound is selected from the following general formula (1), general formula (2) or general formula (3): General formula (1) General formula (2) General formula (3) in: X is selected from non-existent, single bond, oxygen, CR8R9; R1 to R3 are each independently selected from hydrogen, fluorine, substituted or unsubstituted alkyl with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 50 carbon atoms, substituted or unsubstituted cycloalkyl with 6 to 50 carbon atoms, and substituted or unsubstituted silyl with 3 to 30 carbon atoms. R4 to R7 are each independently selected from hydrogen, substituted or unsubstituted alkyl groups with 1 to 30 carbon atoms, or substituted or unsubstituted cyclic groups with 6 to 50 carbon atoms; a, b, c, and d are each independently 0, 1, 2, or 3; R8 and R9 are each independently selected from alkyl groups with 1 to 30 carbon atoms that are substituted or unsubstituted, or aryl groups with 6 to 50 carbon atoms that are substituted or unsubstituted; and R8 and R9 can be linked together to form a ring; when cyclic, R8 and R9 are linked together to form a substituted or unsubstituted fluorene ring. R3 and R5 can each be independently connected to R2 to form a loop.

[0006] 2) The fused heterocyclic compound for organic electroluminescent devices according to 1) above, wherein the fused heterocyclic compound is selected from the following general formula (4), general formula (5) or general formula (6): General formula (4) General formula (5) General formula (6) in: X is selected from non-existent or single bond; R1 to R3 are each independently selected from hydrogen, fluorine, substituted or unsubstituted alkyl with 1 to 10 carbon atoms, substituted or unsubstituted cyclic aryl with 6 to 30 carbon atoms, or substituted or unsubstituted silyl with 3 to 18 carbon atoms; R4 to R7 are each independently selected from hydrogen, substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, or substituted or unsubstituted cyclic groups having 6 to 30 carbon atoms; b is 1 or 2; R3 and R5 can each be independently connected to R2 to form a loop. When a loop is formed, the loop is selected from: .

[0007] 3) The fused heterocyclic compound for organic electroluminescent devices according to 1) or 2) above, wherein R1 to R3 are each independently selected from hydrogen, fluorine, tert-butyl, substituted or unsubstituted phenyl, and triphenylsilyl.

[0008] 4) A fused heterocyclic compound for organic electroluminescent devices according to 1) or 2) above, wherein R4 to R7 are each independently selected from hydrogen, tert-butyl, substituted or unsubstituted phenyl groups.

[0009] 5) The fused heterocyclic compound for organic electroluminescent devices according to 1) or 2) above, wherein "substituted or unsubstituted" in the compound means that the substituent is independently selected from deuterium, tritium, halogen, cyano, nitro, hydroxyl, monovalent alkyl or cycloalkyl with 1 to 10 carbon atoms, monovalent monocyclic aryl or fused cyclic aryl with 6 to 30 carbon atoms, or monovalent heterocyclic group or fused heterocyclic heteroaryl with 2 to 50 carbon atoms.

[0010] 6) A fused heterocyclic compound for an organic electroluminescent device according to 1) or 2) above, wherein the fused heterocyclic compound is selected from the following structures: .

[0011] 7) An organic electroluminescent device, wherein the organic electroluminescent device comprises an anode, a cathode, and at least one organic thin film located between the anode and the cathode, the organic thin film containing any one of the compounds described in 1) to 6) above.

[0012] 8) The organic electroluminescent device according to 7) above, wherein the compound is used as a luminescent material in the organic electroluminescent device.

[0013] Compared with existing technologies, the beneficial effects of this invention are as follows: Compared with the monoboron-nitrogen structure, the diboron-nitrogen structure has a shorter delayed fluorescence lifetime, thereby reducing the quenching of triplet excitons and effectively suppressing efficiency roll-off, improving device efficiency and device lifetime. Simultaneously, the boron and nitrogen atoms in the boron-nitrogen structure are covalently linked, which suppresses intramolecular spatial repulsion, enhances the planarity of the framework, and reduces high-frequency stretching, thereby narrowing the spectrum and improving efficiency. Furthermore, modifying the molecule with different R groups increases its stereochemistry, steric hindrance, and reduces aggregation, thus increasing molecular stability and obtaining a long-lifetime light-emitting device. Attached Figure Description

[0014] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 The diagram below shows the structure of an organic electroluminescent device using the compounds of this invention. The meanings of each layer in the device are as follows: 1. Substrate layer, 2. Anode layer, 3. Hole injection layer, 4. Hole transport layer A, 5. Hole transport layer B (or electron blocking layer), 6. Light-emitting layer, 7. Electron transport layer B (or hole blocking layer), 8. Electron transport layer A, 9. Electron injection layer, 10. Cathode layer, 11. Cover plate layer. Detailed Implementation

[0015] the term In this invention, the alkyl group can be straight-chain or branched. The number of carbon atoms in the alkyl group is not particularly limited, for example, 1 to 30, preferably 1 to 10, and more preferably 1 to 6. Specific examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methylbutyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethylpropyl, 1,1-dimethylpropyl, isohexyl, 4-methylhexyl, and 5-methylhexyl.

[0016] Alkoxy refers to -O-alkyl, wherein the number of carbon atoms is not particularly limited, for example, 1 to 50, preferably 1 to 20, more preferably 1 to 6. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, propoxy (e.g., n-propoxy and isopropoxy) and tert-butoxy.

[0017] In this invention, the aforementioned alkyl or alkoxy groups may be substituted. For example, the number of carbon atoms in fluorinated alkyl or fluorinated alkoxy groups substituted with fluorine is not particularly limited, and is, for example, 1 to 20, more preferably 1 to 6. Examples of fluorinated alkyl groups include, but are not limited to, fluoromethyl, difluoromethyl, trifluoromethyl, trichloromethyl, pentafluoroethyl, 2,2,2-trifluoroethyl, and heptafluoropropyl. Examples of fluorinated alkoxy groups include, but are not limited to, trifluoromethoxy, 2,2,2-trifluoroethoxy, and pentafluoroethoxy.

[0018] The cycloalkyl group can be monocyclic or fused-ring, and the number of carbon atoms is not particularly limited, for example, 3 to 50, preferably 3 to 20, and more preferably 3 to 6. Specific examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and adamantyl, with cyclohexyl being a preferred example.

[0019] The aryl group can be monocyclic or polycyclic, and the number of carbon atoms is not particularly limited, for example, 6 to 50, preferably 6 to 20. Examples of monocyclic aryl groups include, but are not limited to, phenyl, biphenyl, terphenyl, and tetraphenyl. Examples of polycyclic aryl groups include naphthyl, anthraceneyl, phenanthryl, pyrene, perylene, tetraphenyl, fluorenyl, acenaphathcenyl, triphenylene, and fluoranthyl, but the scope of the invention is not limited thereto.

[0020] An arylamine is an aryl-substituted amino group. Examples of arylamines include substituted or unsubstituted monoarylamines, substituted or unsubstituted diarylamines, and substituted or unsubstituted triarylamines. The aryl group in an arylamine can be monocyclic or polycyclic. An arylamine can contain two or more aryl groups. In this case, the aryl group can be a monocyclic or polycyclic aryl group. Alternatively, the aryl group can consist of both monocyclic and polycyclic aryl groups. The aryl group in an arylamine can be selected from those exemplified above. Specific examples of arylamine groups include phenylamine, naphthylamine, biphenylamine, anthraceneamine, diphenylamine, tert-butylphenylamine, di-tert-butylphenylamine, tert-butylbenzylamine, N-phenylnaphthylamine, xylylamine, N-phenyltolylamine, N-phenylbiphenylamine, N-phenylnaphthylamine, N-biphenylnaphthylamine, N-naphthylfluorenylamine, N-phenylphenanthreneamine, N-biphenylphenanthreneamine, N-phenylfluorenylamine, N-phenyltriphenylamine, N-phenanthrenefluorenylamine, N-biphenylfluorenylamine, etc., but are not limited to these. The substituted diphenylamino group in this invention includes the above-mentioned N-phenylnaphthylamino, xylylamino, N-phenyltolylamino, N-phenylbiphenylamino, N-phenylnaphthylamino, N-biphenylnaphthylamino, N-naphthylfluorenylamino, N-phenylphenanthreneamino, N-biphenylphenanthreneamino, N-phenylfluorenylamino, N-phenyltriphenylamino, N-phenanthrenefluorenylamino, and N-biphenylfluorenylamino.

[0021] A "heterocyclic group" is a cyclic compound group in which one or more atoms in the ring are replaced by heteroatoms other than carbon (such as nitrogen, oxygen, sulfur, etc.). A fused-ring heteroaryl group is a cyclic compound group in which at least two rings (at least one of which is an aromatic ring) share one or more carbon atoms, and at least one ring contains one or more heteroatoms. Examples of heterocyclic groups and fused-ring heteroaryl groups include, but are not limited to, thiophene, furanyl, pyrrole, imidazolyl, triazolyl, azole, diazolyl, triazolyl, pyridinyl, bipyridinyl, pyrimidinyl, triazinyl, acridine, pyridazinyl, quinolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, pyridopyrimidinyl, pyridopyrazinyl, pyrazinopyrazinyl, isoquinolinyl, indolyl, carbazole, benzozolyl, benzazole, benzimidazolyl, benzothiazolyl, benzocarbazole, benzothiaphenyl, dibenzothiaphenyl, benzofuranyl, dibenzofuranyl, thiazolyl, isozolyl, diazolyl, thiadiazolyl, benzothiazolyl, and phenothiazinyl.

[0022] "Number of carbon atoms in the ring" refers to the number of carbon atoms that make up the ring structure skeleton, excluding carbon atoms contained in substituents on the ring, and also excluding heteroatoms other than carbon in the ring-forming atoms. For example, the number of carbon atoms in the ring of a phenyl group is 6, that of a naphthyl group is 10, that of a biphenyl group is 12, and that of a 9,9-dimethylfluorenyl group is 13 (excluding the carbon atoms of the two methyl groups). When an aryl group is substituted by an alkyl or aryl group, the number of carbon atoms of the substituent is not included in the number of carbon atoms in the ring.

[0023] In this invention, when two or more substituents are "interconnected to form a ring," the ring can be a saturated or unsaturated carbocyclic or heterocyclic ring, with a ring size of 5 to 10 members, preferably a 5- or 6-membered ring; the ring can be an aromatic or non-aromatic ring. The formed ring can be further substituted by substituents as defined in the aforementioned "substitution."

[0024] Silyl groups refer to ─SiR3 type groups with silicon atoms as the linking point, where R is alkyl or aryl. This includes alkyl-substituted silyl groups, aryl-substituted silyl groups, and mixed alkyl / aryl substituted silyl groups. The number of carbon atoms in a silyl group is not particularly limited, for example, 3 to 30, preferably 3 to 18. Specific examples of such silyl groups include trimethylsilyl, triethylsilyl, triphenylsilyl, trimethoxysilyl, dimethoxyphenylsilyl, diphenylmethylsilyl, diphenylvinylsilyl, methylcyclobutylsilyl, and dimethylfuranylsilyl.

[0025] In the phrase “substituted or unsubstituted,” “substituted” means that one or more hydrogen atoms in the corresponding group are independently replaced by one or more substituents selected from the following groups: (1) Deuterium atom; (2) Halogen atoms, including fluorine atoms, chlorine atoms, and bromine atoms; (3) Cyano, Nitro, Hydroxyl; (4) A monovalent alkyl group having 1 to 10 carbon atoms, wherein the alkyl group is a straight-chain or branched alkyl group, and specific examples include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, and n-decyl; (5) Monovalent cycloalkyl groups with 3 to 10 carbon atoms, including but not limited to cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl; (6) Monovalent alkoxy groups with 1 to 10 carbon atoms, including but not limited to methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, and tert-butoxy; (7) A monovalent monocyclic aryl group with 6 to 30 carbon atoms, including but not limited to phenyl, biphenyl, triphenyl, and tetraphenyl; (8) Monovalent fused-ring aryl groups with 10 to 30 carbon atoms, including but not limited to naphthyl, anthracene, phenanthryl, pyrene, perylene, tetraphenyl, fluorenyl, 9,9-dimethylfluorenyl, acenaphthene, triphenylene, and fluoranthyl; (9) Monovalent monocyclic heteroaryl groups with 5 to 30 cyclic atoms, including but not limited to pyridinyl, pyrimidinyl, pyrazinyl, pyridazinyl, triazinyl, thiopheneyl, furanyl, pyrroleyl, imidazolyl, oxazolyl, and thiazolyl; (10) Monovalent fused-ring heteroaryl groups with 9 to 50 cyclic atoms, including but not limited to quinolinyl, isoquinolinyl, quinazolinyl, quinoxalinyl, phthalazinyl, acridineyl, carbazoyl, indolyl, benzimidazolyl, benzothiopheneyl, dibenzothiopheneyl, benzofuranyl, dibenzofuranyl, benzoxazolyl, benzothiazolyl, phenothiazinyl, phenothiazinyl; (11) Monovalent silyl groups with 3 to 30 carbon atoms, including but not limited to trimethylsilyl, triethylsilyl, triphenylsilyl, dimethylphenylsilyl, and diphenylmethylsilyl.

[0026] When "substitution" refers to multiple substitutions, the substituents may be the same or different; when "substituted or unsubstituted" is not specified before a group, the group is unsubstituted.

[0027] The term "deuterated" in "deuterated or undeuterated" refers to one or more deuterated or fully deuterated substances.

[0028] The specific synthesis steps are as follows: Synthesis Example 1

[0029] Synthesis of intermediate M002-1: 3,6-Di-tert-butylcarbazole C001 (8.37 g, 30 mmol), 1-bromo-2-chloro-3-fluorobenzene C002 (7.53 g, 36 mmol), cesium carbonate (19.56 g, 60 mmol), and 100 mL of N,N-dimethylformamide (DMF) were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 80 °C for 12 h. The reaction was stopped, cooled to room temperature, and 200 mL of deionized water was added. The reaction solution was transferred to a separatory funnel and extracted. The extract was dried over anhydrous magnesium sulfate and concentrated. The sample was purified by silica gel column chromatography to obtain product M002-1, 12.77 g solid, yield 91%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 468.1 [M+H]. + ; Synthesis of intermediate M002-2: Intermediate M002-1 (11.68 g, 25 mmol), o-chloroaniline C003 (3.18 g, 25 mmol), tris(dibenzylindeneacetone)palladium (Pd2dba3, 0.46 g, 0.50 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (X-Phos, 0.47 g, 1.00 mmol), sodium tert-butoxide (4.81 g, 50 mmol), and 100 mL of toluene were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 80 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The reaction solution was then transferred to a separatory funnel and extracted. The extract was dried and concentrated with anhydrous magnesium sulfate, and the sample was purified by silica gel column chromatography to obtain product M002-2, 11.18 g solid, yield 87%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 515.1 [M+H]. + ; Synthesis of intermediate M002-3: Intermediate M002-2 (10.3 g, 20 mmol), m-bromoiodobenzene C004 (5.94 g, 21 mmol), tris(dibenzylindeneacetone)palladium (Pd2dba3, 0.37 g, 0.40 mmol), 1,1'-bis(diphenylphosphine)ferrocene (dppf, 0.44 g, 0.80 mmol), sodium tert-butoxide (3.84 g, 40 mmol), and 100 mL of toluene were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 100 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The reaction solution was then transferred to a separatory funnel and extracted. The extract was dried and concentrated with anhydrous magnesium sulfate, and the sample was purified by silica gel column chromatography to obtain product M002-3, 10.55 g solid, yield 79%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 669.1 [M+H]. + ; Synthesis of intermediate M002-4: Intermediate M002-3 (10.0 g, 15 mmol), 3,6-di-tert-butyl-1-borate pinacol ester-9H-carbazole C005 (6.08 g, 15 mmol), tetrakis(triphenylphosphine)palladium (Pd(PPh3)4, 0.69 g, 0.60 mmol), potassium carbonate (8.28 g, 60 mmol), 100 mL toluene, and 30 mL water were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 100 °C for 12 h. The reaction was stopped, cooled to room temperature, and 100 mL of deionized water was added. The reaction solution was transferred to a separatory funnel and extracted. The extract was dried over anhydrous magnesium sulfate and concentrated. The sample was purified by silica gel column chromatography to obtain product M002-4, 10.8 g solid, yield 83%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 868.4 [M+H]. + ; Synthesis of product FD002: Under nitrogen protection, intermediate M002-4 (8.67 g, 10 mmol) was added to 50 mL of tert-butylbenzene, and... A solution of tert-butyllithium in n-hexane (20.0 mL, 32 mmol, 1.6 M) was added dropwise at 78 °C. After the addition was complete, the mixture was stirred at room temperature for 2 hours. After adding boron tribromide (11.3 g, 45 mmol) dropwise at 78 °C, the resulting mixture was stirred at room temperature for 1 hour, and N₂ and N₃ were added dropwise to it at 0 °C. Diisopropylethylamine (7.92 g, 60 mmol). After the addition was complete, the mixture was stirred at 130 °C for 2 hours. The reaction was stopped, cooled to room temperature, and 50 mL of deionized water was added. The reaction solution was then transferred to a separatory funnel for extraction. The extract was dried over anhydrous magnesium sulfate and concentrated, and the sample was purified by silica gel column chromatography to obtain product FD002, 3.91 g of orange solid, yield 48%; the molecular weight determined by liquid chromatography-mass spectrometry was m / z = 816.4 [M+H]. + .

[0030] Synthesis Example 2

[0031] The synthesis conditions for product FD011 are the same as those for product FD002, except that C001 and C003 are replaced by C006 and C007 respectively; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 908.4 [M+H]. + .

[0032] Synthesis Example 3

[0033] The synthesis conditions for product FD016 are the same as those for product FD002, except that C001, C002, C003, and C004 are replaced by C008, C009, C010, and C011, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1036.5 [M+H]. + .

[0034] Synthesis Example 4

[0035] The synthesis conditions for product FD022 are the same as those for product FD002, except that C002, C003, and C004 are replaced by C012, C010, and C013, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1024.5 [M+H]. + .

[0036] Synthesis Example 5

[0037] Synthesis of intermediate M029-1: Di(4-biphenyl)amine C014 (8.37 g, 30 mmol), 1-bromo-2-chloro-3-iodo-biphenyl C015 (14.08 g, 36 mmol), tris(dibenzylindeneacetone)palladium (Pd2dba3, 0.56 g, 0.60 mmol), 4,5-bis(diphenylphosphine-9,9-dimethyloxanthracene) (XantPhos, 0.69 g, 1.20 mmol), sodium tert-butoxide (5.76 g, 60 mmol), and 100 mL of toluene were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 100 °C for 12 h. The reaction was stopped, cooled to room temperature, and 200 mL of deionized water was added. The reaction solution was then transferred to a separatory funnel and extracted. The extract was dried and concentrated with anhydrous magnesium sulfate, and the sample was purified by silica gel column chromatography to obtain product MO29-1, 16.32 g solid, yield 93%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 586.1 [M+H]. + ; The synthesis conditions for product FD029 are the same as those for product FD022, except that C012, C010, and C005 are replaced by C015, C007, and C016, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1126.4 [M+H]. + .

[0038] Synthesis Example 6

[0039] The synthesis conditions for product FD034 are the same as those for product FD029, except that C014 and C007 are replaced by C017 and C003, respectively; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 1048.4 [M+H]. + .

[0040] Synthesis Example 7

[0041] The synthesis conditions for product FD040 are the same as those for product FD016, except that C010 and C005 are replaced by C003 and C016 respectively; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 1020.4 [M+H]. + .

[0042] Synthesis Example 8

[0043] The synthesis conditions for product FD046 are the same as those for product FD034, except that C015, C003, and C013 are replaced by C009, C018, and C011, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1266.5 [M+H]. + .

[0044] Synthesis Example 9

[0045] The synthesis conditions for product FD053 are the same as those for product FD022, except that C010 is replaced with C019; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1102.6 [M+H]. + .

[0046] Synthesis Example 10

[0047] The synthesis conditions for product FD061 are the same as those for product FD002, except that C002, C003, and C004 are replaced by C009, C020, and C011, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1054.6 [M+H]. + .

[0048] Synthesis Example 11

[0049] The synthesis conditions for product FD068 are the same as those for product FD053, except that CO21 is used instead of CO19; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 1134.5 [M+H]. + .

[0050] Synthesis Example 12

[0051] The synthesis conditions for product FD073 are the same as those for product FD029, except that C014, C015, C007, C013, and C016 are replaced by C022, C009, C010, C011, and C005, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1042.7 [M+H]. + .

[0052] Synthesis Example 13

[0053] The synthesis conditions for product FD085 are the same as those for product FD073, except that CO23 is used instead of CO11; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 1283.8 [M+H]. + .

[0054] Synthesis Example 14

[0055] The synthesis conditions for product FD090 are the same as those for product FD061, except that C020 and C011 are replaced by C003 and C023, respectively; the molecular weight measured by liquid chromatography-mass spectrometry is m / z = 1147.9 [M+H]. + .

[0056] Synthesis Example 15

[0057] Synthesis of intermediate M096-1: 3,6-Di-tert-butylcarbazole C001 (8.37 g, 30 mmol), 1-bromo-2-chloro-3-fluoro-4-iodobenzene C024 (12.06 g, 36 mmol), cesium carbonate (19.56 g, 60 mmol), and 100 mL of N,N-dimethylformamide (DMF) were added to a reaction flask. The reaction system was purged three times under nitrogen protection. The mixture was heated and stirred at 80 °C for 12 h. The reaction was stopped, cooled to room temperature, and 200 mL of deionized water was added. The reaction solution was transferred to a separatory funnel and extracted. The extract was dried over anhydrous magnesium sulfate and concentrated. The sample was purified by silica gel column chromatography to obtain product M096-1, 14.79 g of solid, yield 83%; the molecular weight was determined by liquid chromatography-mass spectrometry to be m / z = 594.0 [M+H]. + ; Synthesis of intermediate M096-2: Weigh intermediate M096-1 (11.88 g, 20 mmol) and dissolve it in anhydrous THF. Stir at -78°C for 10 minutes. Under nitrogen protection, add 8.4 mL (21 mmol, 2.5 M) of n-butyllithium in n-hexane dropwise to the reaction mixture. After the addition is complete, maintain the temperature and stir for 1 hour. Weigh C025 fluorenone (8.3 g, 23 mmol) and add it to the reaction mixture at -78°C. Allow the mixture to cool to room temperature and react for 10 hours. Quench the reaction with 50 mL of water, extract three times with dichloromethane / water, collect the organic phase, remove the solvent by rotary evaporation, and separate by silica gel column chromatography to obtain the crude product. Dissolve the crude product in 50 mL of dichloromethane, stir at room temperature, and add 2.4 mL (20 mmol) of boron trifluoride diethyl ether dropwise under nitrogen protection. Stir at room temperature for 1 hour. Stop the reaction, neutralize the reaction mixture with sodium carbonate solution, and extract three times with dichloromethane. The solvent was removed by rotary evaporation, followed by silica gel column chromatography to obtain product M096-2, 9.70 g solid, yield 77%; liquid chromatography-mass spectrometry determined the molecular weight to be m / z = 630.1 [M+H]. + ; Synthesis of product FD096 The synthesis conditions for product FD096 are similar to those for product FD002, except that C003 and C004 are replaced by C010 and C011, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1096.6 [M+H]. + .

[0058] Synthesis Example 16

[0059] The synthesis conditions for product FD098 are similar to those for product FD002, with the difference being that CO26 is used instead of CO002 to synthesize M098-1, M098-2, M098-3, M098-4, and FD098; the synthesis of M098-5 is the same as that of M096-2; and the molecular weight of FD098, as determined by liquid chromatography-mass spectrometry, is m / z = 978.5 [M+H]. + .

[0060] Synthesis Example 17

[0061] The synthesis conditions for product FD108 are similar to those for product FD098, except that C004 and C025 are replaced by C011 and C027, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1146.6 [M+H]. + .

[0062] Synthesis Example 18

[0063] The synthesis conditions for product FD112 are similar to those for product FD096, except that C025 is replaced with C028; and the molecular weight, as determined by liquid chromatography-mass spectrometry, is m / z = 1166.6 [M+H]. + .

[0064] Synthesis Example 19

[0065] The synthesis conditions for product FD120 are similar to those for product FD096, except that C001, C010, C011, and C005 are replaced by C017, C003, C029, and C016, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1076.3 [M+H]. + .

[0066] Synthesis Example 20

[0067] The synthesis conditions for product FD130 are the same as those for product FD002, except that C002, C003, and C004 are replaced by C030, C031, and C032, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 928.5 [M+H]. + .

[0068] Synthesis Example 21

[0069] The synthesis conditions for product FD147 are the same as those for product FD130, except that C001, C030, C032, and C005 are replaced by C033, C034, C035, and C016, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1050.4 [M+H]. + .

[0070] Synthesis Example 22

[0071] The synthesis conditions for product FD176 are the same as those for product FD147, except that CO33 and CO35 are replaced by CO36 and CO37, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1287.6 [M+H]. + .

[0072] Synthesis Example 23

[0073] The synthesis conditions for product FD182 are the same as those for product FD002, except that C002, C003, and C004 are replaced by C026, C038, and C011, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 928.5 [M+H]. + .

[0074] Synthesis Example 24

[0075] The synthesis conditions for product FD195 are the same as those for product FD182, except that C001, C038, C011, and C005 are replaced by C033, C039, C040, and C016, respectively; the molecular weight determined by liquid chromatography-mass spectrometry is m / z = 1050.4 [M+H]. + .

[0076] Device structure description: The organic electroluminescent device of the present invention comprises an anode layer, a cathode layer, and at least one organic layer between the anode and the cathode. At least one of the organic layers in the organic electroluminescent device of the present invention is a light-emitting layer. In addition to the light-emitting layer, the organic layer may also include other functional layers. For example, one or more hole injection layers, hole transport layers, or electron blocking layers may exist between the anode layer and the light-emitting layer. It is also feasible to have an exciton blocking layer or an intermediate layer with similar function between two light-emitting layers. One or more hole blocking layers, electron transport layers, or electron injection layers may exist between the light-emitting layer and the cathode layer. It should be noted that these functional layers are not necessarily present.

[0077] The organic electroluminescent device described in this invention can be a fluorescent or phosphorescent device, or a hybrid fluorescent and phosphorescent device; it can be a fluorescent sensitized device or a phosphorescent sensitized device; it can be a device with a single light emission, or a device with multiple light-emitting units connected in series; furthermore, it can be a monochromatic light-emitting device, a mixed-color device, or a white light-emitting device.

[0078] The organic electroluminescent device described in this invention can be either a bottom-emitting or top-emitting electroluminescent device. A bottom-emitting electroluminescent device refers to a device structure that emits light through the anode, while a top-emitting electroluminescent device refers to a device structure that emits light through the cathode.

[0079] The luminescent layer can contain multiple guest materials and multiple host materials. Guest materials can be fluorescent materials, phosphorescent materials, and / or thermally activated delayed fluorescence materials. Host materials refer to the matrix material that constitutes the vast majority of the components in the luminescent layer. Host materials doped with fluorescent materials are called "fluorescent hosts," and host materials doped with phosphorescent materials are called "phosphorescent hosts." It should be noted that the selection of host materials does not depend on their molecular structure, but rather on the matrix material that serves as the guest material.

[0080] In addition to the guest and host materials, the luminescent layer may also contain sensitizing materials. These sensitizing materials can be thermally activated delayed fluorescence (TEF) materials or phosphorescent materials. The content of the sensitizing material is typically higher than that of the luminescent guest material but lower than that of the host material. Sensitizing materials can generally improve the utilization rate of excitons in the device by transferring the energy of converted triplet or singlet excitons to the luminescent guest material, thereby improving the device's performance.

[0081] The main material in the light-emitting layer can be a single material or a mixture of multiple materials. The entire light-emitting layer can be prepared by vapor deposition or by solution processing.

[0082] The compounds of the present invention according to the above embodiments can be used in different organic layers. Preferably, the compounds of the present invention are used as the host material, sensitizing material, and guest material of the light-emitting layer in organic electroluminescent devices. The uses of the compounds of the present invention according to the above embodiments are also applicable to organic electronic devices.

[0083] In a preferred embodiment of the present invention, the compound of the present invention is used as a light-emitting guest material in the light-emitting layer of an organic electroluminescent device.

[0084] These methods are generally known to those skilled in the art and can be applied to organic electroluminescent devices containing the compounds of the present invention without any inventive effort.

[0085] Device Example: Fabrication of an Organic Electroluminescent Device Used as a Green Light Emitting Layer Material A 50mm × 50mm × 0.7mm thick glass substrate with an indium tin oxide (ITO) anode was ultrasonically cleaned in isopropanol for 5 minutes. The cleaned glass substrate was then mounted on the substrate holder of a vacuum evaporation apparatus, and a vacuum of 1 × 10⁻⁶ was applied. -5 ~1×10 -6Before depositing the organic material, the substrate was treated with nitrogen plasma for 120 seconds. Then, HT and doped HI were co-deposited on the anode as a hole injection layer (HIL) with a thickness of 10 nm, where the HI doping concentration was 3%. HT was then deposited on top of this hole injection layer as a hole transport layer (HTL) with a thickness of 100 nm. Next, EB was deposited on top of this hole transport layer as an electron blocking layer (EBL) with a thickness of 40 nm. Then, a light-emitting layer (EML) with a thickness of 40 nm was co-deposited on top of this electron blocking layer. The EML was constructed using a multi-source co-deposit method, depositing the host material, sensitizer material, and luminescent material (GH-P / GH-N, PGD, and FD002), where the GH-P:GH-N ratio was 6:4, the sensitizer doping concentration was 5%, and the luminescent material doping concentration was 0.5%. Finally, HB was deposited on top of this light-emitting layer as a hole blocking layer (HBL) with a thickness of 5 nm. Then, on top of the hole-blocking layer, an electron transport material (ET) and lithium 8-hydroxyquinoline (Liq) were co-deposited in a 1:1 ratio as an electron transport layer (ETL) with a film thickness of 30 nm. Furthermore, LiF was deposited on top of the ETL as an electron injection layer (EIL) with a film thickness of 1 nm. Then, metallic Al was deposited on top of the EIL with a film thickness of 100 nm. The fabricated device was transferred to a glove box and sealed with a glass cover. The organic electroluminescent device structure of Example 1 is as follows. Figure 1 As shown, Figure 1 It also shows the stacking order and function of each functional layer.

[0086] The OLED, in principle, has the following layer structure: glass substrate / ITO anode / hole injection layer (HIL) / hole transport layer (HTL) / electron blocking layer (EBL) / light emitting layer (EML) / hole blocking layer (HBL) / electron transport layer (ETL) / electron injection layer (EIL) / cathode. The exact structure of the OLED is shown in Table 1.

[0087] Table 1: Materials used in OLEDs

[0088] Device Example 1: ITO / HT:HI (10nm,3%) / HT (100nm) / EB (40nm) / GH-P:GH-N:PGD:FD002 (40nm,(GH-P:GH-N=6:4),5%,0.5%) / HB (5nm) / ET:Liq (30nm, 50%) / LiF (1nm) / Al(100nm) The only difference between Device Examples 2-24 and Device Example 1 is that the FD002 of the present invention used in the light-emitting layer is replaced with other compounds of the present invention. The performance test data of the resulting devices are shown in Table 2.

[0089] Comparative Examples 1 and 2: The difference between this comparative example and device example 1 is that FD002 in the organic electroluminescent device is replaced with the industry-known Ref-1 and Ref-2. The resulting device performance test data are shown in Table 2.

[0090] The OLED was characterized using standard methods. For this purpose, the electroluminescence spectrum, current efficiency (CE, measured in cd / A), power efficiency (measured in lm / W), and external quantum efficiency (EQE, measured in %) were determined as a function of luminous density from the current / voltage / luminous density characteristic line (IUL characteristic line) exhibiting Lambertian emission characteristics. CE represents the emission at a current density of 10 mA / cm². 2 T90 indicates the current efficiency of the device at a current density of 50 mA / cm². 2 The peak value represents the operating time when the device brightness decreases to 90%, and the peak value represents the device operating at a current density of 10 mA / cm². 2 The emission peaks below. Table 2 summarizes the device performance of Examples 1-24 and Comparative Examples 1-2 of the present invention; Table 2: Device Performance

[0091] As can be seen from Table 2, compared with the prior art, the device efficiency and lifetime of Examples 1-24 using the materials of the present invention are improved. Compared with Comparative Example 1, the device efficiency and lifetime of Example 6, in which FD034 is located, are improved by 12.8% and 43.5%, respectively. Compared with Comparative Example 2, the device efficiency and lifetime of Example 23, in which FD182 is located, are improved by 17.7% and 34%, respectively.

[0092] In summary, the above are merely preferred embodiments of the present invention and are 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 fused heterocyclic compound for use in organic electroluminescent devices, characterized in that, The fused heterocyclic compounds are selected from the following general formulas (1), (2), or (3): General formula (1) General formula (2) General formula (3) in: X is selected from non-existent, single bond, oxygen, CR8R9; R1 to R3 are each independently selected from hydrogen, fluorine, substituted or unsubstituted alkyl with 1 to 30 carbon atoms, substituted or unsubstituted cycloalkyl with 3 to 50 carbon atoms, substituted or unsubstituted cycloalkyl with 6 to 50 carbon atoms, and substituted or unsubstituted silyl with 3 to 30 carbon atoms. R4 to R7 are each independently selected from hydrogen, alkyl groups with 1 to 30 carbon atoms (substituted or unsubstituted), or aryl groups with 6 to 50 carbon atoms (substituted or unsubstituted); a, b, c, and d are each independently selected from 0 to 3. R8 and R9 are each independently selected from alkyl groups with 1 to 30 carbon atoms that are substituted or unsubstituted, or aryl groups with 6 to 50 carbon atoms that are substituted or unsubstituted; and R8 and R9 can be linked together to form a ring; when cyclic, R8 and R9 are linked together to form a substituted or unsubstituted fluorene ring. R3 and R5 can each be independently connected to R2 to form a loop.

2. The fused heterocyclic compound for organic electroluminescent devices according to claim 1, characterized in that, The fused heterocyclic compounds are selected from the following general formulas (4), (5), or (6): General formula (4) General formula (5) General formula (6) in: X is selected from non-existent or single bond; R1 to R3 are each independently selected from hydrogen, fluorine, substituted or unsubstituted alkyl with 1 to 10 carbon atoms, substituted or unsubstituted cyclic aryl with 6 to 30 carbon atoms, or substituted or unsubstituted silyl with 3 to 18 carbon atoms; R4 to R7 are each independently selected from hydrogen, substituted or unsubstituted alkyl groups having 1 to 10 carbon atoms, or substituted or unsubstituted cyclic groups having 6 to 30 carbon atoms; b is 1 or 2; R3 and R5 can each be independently connected to R2 to form a loop. When a loop is formed, the loop is selected from: 。 3. The fused heterocyclic compound for organic electroluminescent devices according to claim 1 or 2, characterized in that, R1 to R3 are each independently selected from hydrogen, fluorine, tert-butyl, substituted or unsubstituted phenyl, and triphenylsilyl.

4. The fused heterocyclic compound for organic electroluminescent devices according to claim 1 or 2, characterized in that, R4 to R7 are each independently selected from hydrogen, tert-butyl, substituted or unsubstituted phenyl groups.

5. The fused heterocyclic compound for organic electroluminescent devices according to claim 1 or 2, characterized in that, In the compound, "substituted or unsubstituted" means that the substituent is independently selected from deuterium, tritium, halogen, cyano, nitro, hydroxyl, monovalent alkyl or cycloalkyl with 1 to 10 carbon atoms, monovalent monocyclic aryl or fused-ring aryl with 6 to 30 carbon atoms, or monovalent heterocyclic or fused-ring heteroaryl with 2 to 50 carbon atoms.

6. The fused heterocyclic compound for organic electroluminescent devices according to claim 1 or 2, characterized in that, The fused heterocyclic compounds are selected from the following structures: 。 7. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an anode, a cathode, and at least one organic thin film located between the anode and the cathode, wherein the organic thin film contains the compound according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that, The compound is used as a luminescent material in organic electroluminescent devices.

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