Luminescent material of organic electroluminescent display device

Abstract

The invention relates to the field of organic electroluminescent materials (OLEDs), in particular to a B / N fused heteroaromatic ring luminescent material structure taking an ortho-spiramine donor as a core and application of the material in an organic electroluminescent display device. The novel luminescent material taking the B / N fused heteroaromatic ring as the core has a structure as shown in a formula (1) or a formula (2). The invention provides a preparation method of the B / N fused heteroaromatic ring organic electroluminescent material taking the ortho-spiroamine donor as the core and an application of the B / N fused heteroaromatic ring organic electroluminescent material as the luminescent material in an organic electroluminescent device.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent materials (OLEDs), specifically to the structure, synthesis process, and application of novel luminescent materials made of polycyclic aromatic organic compounds in organic electroluminescent display devices. Background Technology

[0002] Organic light-emitting diodes (OLEDs), due to their advantages such as low power consumption, wide viewing angle, vibrant colors, and flexibility, have long been a focus of attention in academia and industry as a novel technology in the display and lighting fields. Electroluminescence was first observed by G. Destriau in 1936, but it did not receive the attention it deserved. It wasn't until 1987 that Dr. Ching W. Tang and others at Kodak invented the sandwich-type organic bilayer thin-film electroluminescent device, sparking a technological boom in OLED research worldwide. In 2012, the Adachi research group reported the first TADF material, which exhibits a small ΔE... ST This allows the upconversion channel of the T1 exciton to be opened, achieving 100% exciton utilization. To achieve emission of blue to deep blue light, the molecule needs to have a large Et. g In designing TADF blue light-emitting materials, this is typically achieved by introducing weak electron donor and acceptor units. However, in this case, the ICT effect is often insufficient, leading to ΔE... ST The relatively large value weakens or completely eliminates its TADF property. Furthermore, to achieve a smaller ΔE... ST These molecules require the design of a twisted DA structure. This twisted structure enhances molecular relaxation. Therefore, blue light molecules designed in this way all exhibit broad-spectrum emission, making it difficult to meet the color purity requirements of high-resolution displays. In 2016, Hatakeyama et al. reported two BN-MR molecules, DABNA-1 and DABNA-2. Their λ in dichloromethane solution... PL 462nm and 470nm respectively, FWHM PL The wavelengths are 33 nm and 34 nm, respectively. The device fabricated using DABNA-1 molecules has an efficiency of 13.5%. Due to their rigid structure and short local CT state characteristics, this type of BN-MR molecule is an ideal structure for fabricating narrow-spectrum blue light-emitting materials.

[0003] Organic light-emitting materials (OLEDs) are core materials for electroluminescent devices, especially those organic materials with blue light emission properties, one of the three primary colors of light, which have been actively researched. A key difference between small-molecule OLED materials and component design and polymer materials lies in enabling the rapid commercialization of small-molecule OLED panel technology. To improve the luminous efficiency, brightness, and stability of the device, the emissive layer is composed of high-fluorescence-efficiency materials doped into the host molecule. Therefore, it is necessary to continue developing optimized organic light-emitting device structures to improve their luminous characteristics, as well as novel blue light-doping materials that can support these optimized structures. Summary of the Invention

[0004] The purpose of this invention is to provide a novel ortho-spiroamine donor that, by utilizing the rigid plane of naphthalene and the spatially perpendicular characteristics of the fluorene group, can produce a narrow-band organic light-emitting device with low-efficiency roll-off.

[0005] The novel luminescent material of the present invention, with ortho-spiroamine B / N hybrid molecules as the core, has the structures shown in formulas (1) to (29):

[0006] In formulas (1) to (29), the A ring, B ring, C ring, D ring, E ring, F ring, G ring, H ring, and I ring are each independently selected from aromatic rings, heteroaryl rings, or aliphatic rings, and there is at least one heteroaryl ring;

[0007] Take R1-R 15 Each of the following groups is independently selected from hydrogen, deuterium, cyano, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkoxy, substituted or unsubstituted spirocyclic, substituted or unsubstituted fused cyclic, or can be linked with adjacent substituents to form a monocyclic or polycyclic aliphatic or aromatic cyclic group.

[0008] X and Y are each independently selected from any one of the following: oxygen atom, sulfur atom, selenium atom, straight-chain or branched substituted or unsubstituted alkylene group, aryl-substituted alkylene group, alkyl or aryl-substituted tertiary amino group.

[0009] Among them, the polycyclic aromatic organic compound is characterized in that the A ring, B ring, C ring, D ring, E ring, F ring, G ring, H ring and I ring are each independently selected from C6-C60 aromatic rings, C3-C50 heteroaryl rings or C3-C30 aliphatic rings;

[0010] Preferably, rings A, B, C, D, E, F, G, H, and I are each independently selected from any one of the following: benzene ring, benzopyrrole ring, benzofuran ring, benzothiophene ring, biphenyl ring, furan ring, pyrrole ring, thiophene ring, 1,3-cyclopentadiene ring, benzo-1,3-cyclopentadiene ring, and benzo-1,2-cyclopentadiene ring.

[0011] More preferably, at least one of rings A, B, C, D, E, F, G, H, and I is a ring as shown in equation (30):

[0012] Equation (30), where Z is -O-, -S-, -C(R) 16 R 17 )-,-N(R 18 R 19 )-,-Si(R 20 R 21 Any one of the following: J ring represents an aromatic ring, a heteroaryl ring, or an aliphatic ring;

[0013] R 16 -R 21 Each is independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C3-C24 heteroaryl, substituted or unsubstituted C1-C6 alkoxy, and substituted or unsubstituted C5-C30 spirocyclic.

[0014] Preferably, the molecular structures in formulas (1) to (29) include, but are not limited to, the following structural formulas:

[0015] The second objective of this invention is to provide a method for preparing the above-mentioned organic electroluminescent material, characterized in that the reaction equation occurring during the preparation process is as follows:

[0016] In the reaction route, R is independently selected from hydrogen, deuterium, cyano, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkoxy, substituted or unsubstituted spirocyclic, substituted or unsubstituted fused cyclic, or can be linked with adjacent substituents to form monocyclic or polycyclic aliphatic or aromatic cyclic groups.

[0017] The specific reaction steps in the reaction route are as follows: In a nitrogen or argon atmosphere, the ortho-spiroamine-substituted compound and boron tribromide are placed in an ortho-dichlorobenzene solution. After reacting the above reactant mixture at 180°C for 12 to 24 hours, the mixture is cooled, filtered through diatomaceous earth, evaporated under reduced pressure, and subjected to silica gel column chromatography to obtain the target product.

[0018] The molar ratio of the ortho-spiroamine-substituted compound to boron tribromide is 1:(1-10);

[0019] The third objective of this invention is to apply B / N-fused aromatic ring luminescent material molecules with ortho-spiroamine donors as the core to the fabrication of organic electroluminescent devices. The organic electroluminescent device using this type of material as the luminescent material is characterized by comprising, from bottom to top, an ITO conductive glass substrate (anode), a hole injection layer, a hole transport layer, an electron blocking layer, a luminescent layer (the organic electroluminescent molecular material and sensitizer involved in this invention are doped into the host material), an electron transport layer, an electron injection layer, and a cathode layer.

[0020] The organic electroluminescent device was prepared by vacuum evaporation. The molecular structure of the organic compound used in the device is as follows: The beneficial effects of this invention are:

[0021] The B / N fused aromatic ring luminescent material molecule with ortho-spiroamine donor as the core provided by this invention has good thermal stability and photoelectric properties.

[0022] The B / N hybrid aromatic ring luminescent material molecule provided by this invention, with an ortho-spiroamine donor as the core, has a fluorene group portion that is perpendicularly arranged to the naphthalene ring. This helps to reduce the π-π interaction between molecules and improve the device efficiency roll-off problem caused by molecular π-π stacking.

[0023] The luminescent material produced by this invention is used in the fabrication of blue OLED devices, exhibiting excellent device performance and promising prospects for industrial application.

[0024] The B / N-fused aromatic ring luminescent material molecule produced by this invention, with an ortho-spiroamine donor as the core, has a narrow half-maximum width and provides a new design idea for constructing luminescent materials with non-traditional structures. Attached Figure Description

[0025] Figure 1 This is the single-crystal spectrum of compound A.

[0026] Figure 2 This is the 1H NMR spectrum of compound B.

[0027] Figure 3 This is the carbon NMR spectrum of compound B.

[0028] Figure 4 TGA for compounds A and B.

[0029] Figure 5 This is a schematic diagram of the structure of an organic electroluminescent device prepared using A and B as luminescent materials.

[0030] Figure 6 The test results are for organic electroluminescent devices prepared using A and B as luminescent materials.

[0031] Figure 7 The electroluminescence (EL) emission spectrum of an organic electroluminescent device prepared using A and B as luminescent materials is shown. Detailed Implementation

[0032] To better understand the content of this invention, specific examples are provided below to explain the invention, but this is not intended to limit the scope of the invention.

[0033] Example 1: Preparation of compound A Compound 3 (1.6 g, 5.0 mmol), compound 2 (5.2 g, 10.0 mmol), palladium acetate (45.3 mg, 0.2 mmol), tri-tert-butylphosphine tetrafluoroborate (232.1 mg, 0.8 mmol), and sodium tert-butoxide (1.2 g, 12.0 mmol) were added sequentially to a Schlenk reaction tube with a magnetic stir bar. After evacuating the tube with nitrogen (3 times), a dry toluene solution (30.0 mL) was added under a nitrogen atmosphere. The reaction was carried out at 110 °C for 12 hours. After the system cooled to room temperature, it was filtered through diatomaceous earth and the filter cake was washed three times with dichloromethane. The filtrate was collected and the solvent was removed by vacuum distillation. The residue was subjected to silica gel (100-200 mesh) column chromatography (petroleum ether / dichloromethane = 4:1, v / v) to give a white solid 1a (4.5 g, 3.8 mmol, 75% yield). A magnetic stir bar was added to a Schlenk reaction tube, and the mixture was dried under reduced pressure and by flame drying. Compound 1a (237.5 mg, 0.2 mmol) was added to the Schlenk reaction tube. After purging with nitrogen using a double-row tube (3 times), o-dichlorobenzene (2.0 mL) and boron tribromide (0.5 mL, 0.5 mmol) were added under a nitrogen atmosphere. The reaction mixture was stirred at 180 °C for 24 hours, and then cooled to 0 °C. N,N-diisopropylethylamine (DIPEA, 9.3 mL, 56.0 mmol) was then added to the system. After the system cooled to room temperature, it was filtered through diatomaceous earth and the filter cake was washed three times with dichloromethane. The filtrate was collected, and the solvent was removed by vacuum distillation. The residue was subjected to silica gel (100-200 mesh) column chromatography (petroleum ether / dichloromethane = 4:1, v / v) to give a yellow solid (17.3 mg, 14.4 μmol, 7% yield). 1HNMR (400MHz, CDCl3): δ (ppm) 10.78 (s, 1H), 9.42 (d, J = 8.0Hz, 2H), 7.98 (d, J = 7.6Hz, 4H),7.89-7.87(m,4H),7.53(t,J=8.0Hz,2H),7.46(t,J=7.6Hz,4H),7.18-7.09(m,7H ), 7.04-6.98(m,9H), 6.82(d,J=7.2Hz,2H), 5.96(s,18H), 5.94(s,18H), 1.74(s,12H), 0.66(s,18H). HRMS(ESI+,m / z):C88H69B2N4[M+H]+, calculated value: 1203.5703; measured value: 1203.5703. The carbon spectrum signal is weak; the structure was further determined using single-crystal diffraction (see [reference]). Figure 1 See Table 1.

[0034] The crystal data of compound A are shown in Table 1.

[0035] Example 2: Preparation of compound B In a Schlenk reaction tube equipped with a magnetic stirrer, compound 1,3-dibromo-5-(tert-butyl)benzene (1.5 g, 5.0 mmol), compound 1 (3.1 g, 10.0 mmol), palladium acetate (45.3 mg, 0.2 mmol), tritert-butylphosphine tetrafluoroborate (232.1 mg, 0.8 mmol), and sodium tert-butoxide (1.2 g, 12.0 mmol) were added sequentially. After evacuating the tube with a double-row tube and backfilling with nitrogen (3 times), a dry toluene solution (30 mL) was added under a nitrogen atmosphere. The reaction was carried out at 110 °C for 12 hours. After the system cooled to room temperature, it was filtered through diatomaceous earth and the filter cake was washed three times with dichloromethane. The filtrate was collected and the solvent was removed by vacuum distillation. The residue was subjected to silica gel (100-200 mesh) column chromatography (petroleum ether / dichloromethane = 4:1, v / v) to give a white solid 2a (3.2 g, 4.2 mmol, 84% yield). A magnetic stir bar was then added to a Schlenk reaction tube, and the mixture was dried under reduced pressure and flame. Compound 2a (148.2 mg, 0.2 mmol) was added to the Schlenk reaction tube, and the mixture was purged with nitrogen (3 times) using a double-row tube. Under a nitrogen atmosphere, o-dichlorobenzene (2.0 mL) and boron tribromide (0.5 mL, 0.5 mmol) were added. The reaction mixture was stirred at 180 °C for 24 hours, and then cooled to 0 °C. N,N-diisopropylethylamine (DIPEA, 9.3 mL, 56.0 mmol) was then added to the system. After cooling to room temperature, the mixture was filtered through diatomaceous earth and the filter cake was washed three times with dichloromethane.The filtrate was collected and the solvent was removed by vacuum distillation. The residue was subjected to silica gel (100-200 mesh) column chromatography (petroleum ether / dichloromethane = 4:1, v / v) to give a yellow solid (16.2 mg, 20.0 μmol, yield 11%). The chromatograms were: 8.86 (d, J = 8.8 Hz, 2H), 7.90 (d, J = 8.0 Hz, 4H), 7.78 (d, J = 8.0 Hz, 2H), 7.61 (d, J = 8.4 Hz, 2H), 7.45 (t, J = 7.6 Hz, 2H), 7.39 (t, J = 7.6 Hz, 4H), 7.07 (t, J = 7.2 Hz, 4H), 6.92 (d, J = 7.6 Hz, 4H), 6.73 (d, J = 7.2 Hz, 2H), 5.78 (s, 2H), 0.35 (s, 9H). 13C NMR (101MHz, CDCl3): δ (ppm) 152.1, 148.3, 148.1, 143.9, 141.1, 140.0, 132.2, 130.1, 129.8, 128.8, 128.5, 128.2, 124.9, 123.3, 120.3, 115.8, 114.8, 113.6, 111.9, 100.8, 83.2, 34.2, 30.5. HRMS (ESI+, m / z): C56H38BN2[M+H]+, calculated value: 749.3123; measured value: 749.3121.

[0036] This invention uses compounds A and B as luminescent materials to fabricate organic electroluminescent devices, and commercially available phosphorescent materials as the luminescent materials. It should be understood that the device implementation process and results are only for better explanation of this invention and are not intended to limit the invention.

[0037] Organic electroluminescent devices were prepared according to the following method: 1. Cleaning ITO (Indium Tin Oxide) Glass: Wash with alkali and deionized water in sequence until the water on the surface neither gathers into droplets nor flows down in streams. After drying, treat it in a plasma cleaner for 10 minutes. 2. Hole transport layer TAPC (30nm) and electron blocking layer TCTA (10nm) are sequentially vacuum-deposited on the anode ITO glass at a deposition rate of 0.1nm / s. 3. A co-evaporated optical layer is deposited on top of the electron blocking layer by vacuum evaporation at a rate of 0.1 nm / s; 4. An electron transport layer TmPyPb (50nm) is vacuum-deposited on top of the light-emitting layer at a deposition rate of 0.1nm / s; 5. LiF (1.0 nm) was vacuum-deposited on the electron transport layer at a deposition rate of 0.08 nm / s; 6. Vacuum evaporation of cathode Al (100nm) is performed on the electron injection layer at a deposition rate of 0.1nm / s.

[0038] Example 1: ITO / TAPC (30nm) / TCTA (10nm) / mCP (10nm) / DOBNA-OAr:1%A (20nm) / TmPyPb (50nm) / LiF (1nm) / Al (100nm);

[0039] Example 2: ITO / TAPC (30nm) / TCTA (10nm) / mCP (10nm) / DOBNA-OAr:1%B (20nm) / TmPyPb (50nm) / LiF (1nm) / Al (100nm);

[0040] The test results of the device are shown in Table 2. Table 2

[0041] Table 2 Data Notes: [a] Brightness is 1000 cd / m² -2 The fluorescence emission peak at that time; [b] luminance of 1 cd m -2 [c] Driving voltage; [d] Maximum external quantum efficiency; [e] Power efficiency; [f] Full width at half maximum (FWHM); [c] CIE coordinates of the device's emission spectrum.

[0042] The above descriptions are merely some embodiments of the present invention and are not intended to limit the present invention. Any modifications or substitutions made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

[0043] While the invention has been disclosed by way of examples and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments. Rather, those skilled in the art will appreciate that it is intended to cover various modifications and similar arrangements. Therefore, the scope of the appended claims should be consistent with the broadest interpretation to cover all such modifications and similar arrangements.

Claims

1. A class of polycyclic aromatic organic compounds, characterized in that... Compounds of formulas (1) to (29) or their isomers: Among them, rings A, B, C, D, E, F, G, H, and I are each independently selected from aromatic rings, heteroaryl rings, or aliphatic rings, with at least one heteroaryl ring; Take R1-R 15 Each of the following groups is independently selected from hydrogen, deuterium, cyano, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkoxy, substituted or unsubstituted spirocyclic, substituted or unsubstituted fused cyclic, or can be linked with adjacent substituents to form a monocyclic or polycyclic aliphatic or aromatic cyclic group. X and Y are each independently selected from any one of the following: oxygen atom, sulfur atom, selenium atom, straight-chain or branched substituted or unsubstituted alkylene group, aryl-substituted alkylene group, alkyl or aryl-substituted tertiary amino group.

2. The polycyclic aromatic organic compound according to claim 1, characterized in that, Rings A, B, C, D, E, F, G, H, and I are each independently selected from C6-C60 aromatic rings, C3-C50 heteroaryl rings, or C3-C30 aliphatic rings; Preferably, rings A, B, C, D, E, F, G, H, and I are each independently selected from any one of the following: benzene ring, benzopyrrole ring, benzofuran ring, benzothiophene ring, biphenyl ring, furan ring, pyrrole ring, thiophene ring, 1,3-cyclopentadiene ring, benzo-1,3-cyclopentadiene ring, and benzo-1,2-cyclopentadiene ring.

3. The polycyclic aromatic organic compound according to claim 2, characterized in that, At least one of the rings A, B, C, D, E, F, G, H, and I is a C3-C50 heteroaryl ring; More preferably, at least one of rings A, B, C, D, E, F, G, H, and I is a ring as shown in equation (30): Equation (30), where Z is -O-, -S-, -C(R) 16 R 17 )-,-N(R 18 R 19 )-,-Si(R 20 R 21 Any one of the following; J ring represents an aromatic ring, a heteroaryl ring, or an aliphatic ring; R 16 -R 21 Each is independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C24 aryl, substituted or unsubstituted C3-C24 heteroaryl, substituted or unsubstituted C1-C6 alkoxy, and substituted or unsubstituted C5-C30 spirocyclic. Preferably, the J ring represents a C6-C60 aromatic ring, a C3-C50 heteroaryl ring, or a C3-C30 aliphatic ring; Preferably, the J rings are independently selected from any one of the following: benzene ring, benzopyrrole ring, benzofuran ring, benzothiophene ring, biphenyl ring, furan ring, pyrrole ring, thiophene ring, 1,3-cyclopentadiene ring, benzo1,3-cyclopentadiene ring, and benzo1,2-cyclopentadiene ring. R 16 -R 21 Each of the following is independently selected from hydrogen, deuterium, methyl, ethyl, tert-butyl, alkoxy, phenyl, methylbenzene, biphenyl, and naphthyl.

4. The polycyclic aromatic compound according to claim 3, characterized in that, Based on the rules of chemical bonding, carbon atoms in rings A, B, C, D, E, F, G, H, I, and J can be replaced by heteroatoms; Preferably, the heteroatom is any one of nitrogen, oxygen, sulfur, silicon, and selenium; More preferably, the hydrogens in rings A, B, C, D, E, F, G, H, I, and J can be replaced by deuterated hydrogens.

5. The polycyclic aromatic organic compound according to claim 1, characterized in that, R1-R 15 The groups are independently selected from hydrogen, deuterium, cyano, halogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C6-C30 arylamino, substituted or unsubstituted C6-C30 heteroaryl, substituted or unsubstituted C1-C6 alkoxy, substituted or unsubstituted C5-C30 spirocyclic, substituted or unsubstituted fused-ring, or C3-C30 aliphatic ring groups or C6-C30 aromatic ring groups that can be linked with adjacent substituents to form monocyclic or polycyclic rings; Preferably, R1-R 15 Each of the following groups is independently selected from hydrogen, deuterium, cyano, fluorine, chlorine, bromine, methyl, ethyl, propyl, cyclopropane, cyclopentane, cyclohexane, isopropyl, tert-butyl, adamantane, 1,3-cyclopentadienyl, 1,2-cyclopentadienyl, methoxy, ethoxy, phenyl, methylbenzene, biphenyl, naphthyl, dibenzofuran, dimethylfluorene, and aromatic amino groups.

6. The polycyclic aromatic organic compound according to claim 1, characterized in that, X and Y are each independently selected from any one of the following: oxygen atom, sulfur atom, selenium atom, C1-C10 straight-chain or branched substituted or unsubstituted alkylene group, C6-C20 aryl-substituted alkylene group, and C1-C10 alkyl or aryl-substituted tertiary amino group.

7. The polycyclic aromatic organic compound according to any one of claims 1-6, characterized in that, The polycyclic aromatic organic compound is selected from any one of the compounds shown in the following structural formulas: Any one of them.

8. An organic electroluminescent device comprising the compound according to any one of claims 1 to 7, characterized in that... The compound is used as a light-emitting material in the light-emitting layer to fabricate OLED devices.

9. A method for preparing a compound comprising any one of claims 1-8, characterized in that... The reaction equations that occur during the preparation process are as follows: In the reaction route, R is independently selected from hydrogen, deuterium, cyano, halogen, substituted or unsubstituted alkyl, substituted or unsubstituted aryl, substituted or unsubstituted alkoxy, substituted or unsubstituted spirocyclic, substituted or unsubstituted fused cyclic, or can be linked with adjacent substituents to form monocyclic or polycyclic aliphatic or aromatic cyclic groups. The specific reaction steps in the reaction route are as follows: In a nitrogen or argon atmosphere, take a compound containing an ortho-spiroamine donor and boron tribromide in an ortho-dichlorobenzene solution. After reacting the above reactant mixture at 180°C for 12 to 24 hours, cool, filter through diatomaceous earth, evaporate under reduced pressure, and then perform silica gel column chromatography to obtain the target product. The molar ratio of the ortho-spiroamine-substituted compound to boron tribromide is 1:(1-10).

10. As described in claims 1-8, the B / N-fused aromatic ring luminescent material molecule with an ortho-spiroamine donor as its core is applied to the fabrication of organic electroluminescent devices, characterized in that, The organic electroluminescent device using this type of material as the light-emitting material consists of, from bottom to top, an ITO conductive glass substrate (anode), a hole injection layer (HAT-CN), a hole transport layer (TAPC), an electron blocking layer (TCTA), a light-emitting layer (the organic electroluminescent molecular material and sensitizer involved in this invention are doped in the host material), an electron transport layer (TmPyPb), an electron injection layer (LiF), and a cathode layer (Al).

11. As described in claim 10, the B / N fused aromatic ring luminescent material molecule with the novel ortho-spiroamine donor as the core has good thermal stability and photoelectric properties, and can obtain pure blue light emission with a narrow half-width (WHM) (<20nm).

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