A compound containing carbazole and an organic electroluminescent device

Abstract

The invention discloses a compound containing carbazole and an organic electroluminescent device. The compound is formed by connecting two carbazoles, triazine and dibenzofuran in a specific manner. Heavy hydrogen (deuterium) is introduced into the traditional organic material of the same type. The introduction of deuterium improves the phase solubility of the material and the doping material, improves the interface stability, and thus greatly improves the luminous efficiency and stability of the device. At the same time, the introduction of deuterium enables the compound to be better matched with the doping material, further improving the life span and luminous efficiency of the device.

Description

Technical Field

[0001] The invention relates to the technical field of organic electroluminescence, and in particular to a compound containing carbazole and an organic electroluminescence device. Background Art

[0002] Organic light-emitting devices (OLED) have been a hot topic in the field of flat panel displays in recent years. Compared with LCD, they have the following advantages:

[0003] Compared to the crystal layers of LEDs (light-emitting diodes) or LCDs (liquid crystal displays), OLED's organic plastic layers are thinner, lighter and more flexible;

[0004] The light-emitting layer of OLED is relatively light, so its substrate can use flexible materials instead of rigid materials. The substrate of OLED is made of plastic, while LED and LCD use glass substrate.

[0005] OLED is a current-type organic light-emitting device. It emits light through the injection and recombination of carriers. The luminous intensity is proportional to the injected current. Under the action of the electric field, the holes generated by the anode and the electrons generated by the cathode will move, inject into the hole transport layer and the electron transport layer respectively, and migrate to the light-emitting layer. When the two meet in the light-emitting layer, energy excitons are generated, which excite the light-emitting molecules and finally produce visible light.

[0006] Since there is a huge gap between the external quantum efficiency and the internal quantum efficiency of OLED, the development of OLED is greatly restricted. Therefore, how to improve the light extraction efficiency of OLED has become a hot topic of research. Total reflection occurs at the interface between ITO film and glass substrate and at the interface between glass substrate and air. The light emitted to the front external space of OLED device accounts for about 20% of the total EL of organic material film. The remaining about 80% of the light is mainly confined in the organic material film, ITO film and glass substrate in the form of waveguide, which seriously restricts the development and application of OLED. How to reduce the total reflection effect in OLED devices and increase the proportion of light coupling to the front external space of the device, thereby improving the performance of the device, has attracted widespread attention.

[0007] In order to fully utilize the excellent characteristics of organic light-emitting devices, the materials that constitute the organic layers in the device, such as hole injection materials, hole transport materials, light-emitting materials, electron transport materials, electron injection materials, etc., must be backed by stable and effective materials, and there is a continuous demand for the development of new materials. Summary of the invention

[0008] Purpose of the invention: In view of the above technical problems, the present invention provides a compound containing carbazole and an organic electroluminescent device.

[0009] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0010] A compound containing carbazole, characterized in that its structural formula is as follows:

[0011]

[0012] R1-R2 are each independently hydrogen, deuterium, deuterated or undeuterated phenyl, deuterated or undeuterated biphenyl;

[0013] L is a single bond, phenyl, or naphthyl;

[0014] R3 is a deuterated C3-C20 cycloalkyl group or a deuterated C6-C20 aromatic group;

[0015] p and n are independently 0, 1, 2, 3, and 4.

[0016] Preferably, R3 is selected from deuterated phenyl, deuterated naphthyl, deuterated phenanthryl, and deuterated C3-C12 cycloalkyl group;

[0017] The L is connected to position 1 of dibenzofuran, and R1-R2 are independently hydrogen, deuterium, deuterated or undeuterated phenyl.

[0018] Furthermore, the R3 is selected from one of the following groups:

[0019]

[0020] Further, it is any one of the following compounds:

[0021]

[0022]

[0023]

[0024]

[0025] An organic electroluminescent device comprises a first electrode, a second electrode and an organic layer formed between the first electrode and the second electrode, wherein the organic layer contains the above compound.

[0026] Furthermore, the organic layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer; and at least one of the hole injection layer, the first hole transport layer, the second hole transport layer, the light-emitting layer, the hole blocking layer, the electron transport layer, and the electron injection layer contains the above-mentioned compound.

[0027] Furthermore, the light-emitting layer contains the above-mentioned compound.

[0028] Furthermore, the light-emitting layer further contains at least one of the following compounds G1-G56:

[0029]

[0030]

[0031] An electronic display device containing the organic electroluminescent device.

[0032] An OLED lighting device comprising the organic electroluminescent device. The room temperature in the present invention is 25±5°C.

[0033] Beneficial effects of the present invention:

[0034] The present invention designs a compound used as an organic electroluminescent material, which has the following characteristics: First, the organic electroluminescent material of the present invention introduces heavy hydrogen (deuterium) into the traditional organic material of this type. The introduction of deuterium improves the phase solubility of this type of material with the doping material, improves the interface stability, and thus greatly improves the luminous efficiency and stability of the device. At the same time, the introduction of deuterium enables this type of compound to be better matched with the doping material, further improving the life and luminous efficiency of the device. Second, deuterium can lead to the weakening of the vibration within the material molecule, thereby reducing the occurrence of non-radiative transitions, improving the internal quantum efficiency of the material, and at the same time improving the stability of the device, thereby improving the luminous efficiency and life of the device, and the introduction of deuterium can adjust the molecular weight of the material, adjust its evaporation temperature, so that it can be better matched with the electron-donating group material, and improve the stability and life of the device. Third, there are two carbazoles in the material molecule, and the carbazole group has a higher triplet energy level, resulting in the compound of the present invention having a higher triplet energy level. This characteristic effectively avoids the reverse transfer of energy from the doping material to the main material, thereby improving the luminous efficiency of the device.

[0035] Device verification shows that the organic electroluminescent device prepared using the compound designed by the present invention has better luminous efficiency and lifespan. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of the organic electroluminescent device of the present invention.

[0037] The numbers in the figure represent:

[0038] 1- anode, 2- hole injection layer, 3- first hole transport layer, 4- second hole transport layer, 5- light emitting layer, 6- hole blocking layer, 7- electron transport layer, 8- electron injection layer, 9- cathode.

[0039] Figure 2 This is the HPLC chart of compound 1 prepared in Example 1 of the present invention.

[0040] Figure 3 is the DSC spectrum of compound 1 prepared in Example 1 of the present invention, Figure 3 It can be seen that the Tm value of compound 1 is 304.33°C.

[0041] Figure 4 is the TGA spectrum of compound 1 prepared in Example 1 of the present invention, Figure 4 It can be seen that the thermal weight loss temperature Td value is 477.67℃.

[0042] Figure 5 is a life graph of the organic electroluminescent device in Application Example 1 and Comparative Example 1 of the present invention; Figure 5 It can be seen that the T97% lifespans of the organic electroluminescent devices prepared in Application Example 1 and Comparative Example 1 of the present invention are 621 h and 454 h, respectively. DETAILED DESCRIPTION

[0043] The following further illustrates and describes embodiments of various aspects. It should be understood that the description herein is not intended to limit the claims to the specific aspects described. On the contrary, it is intended to cover substitutions, modifications and equivalents that may be included in the spirit and scope of the present disclosure defined by the appended claims.

[0044] As used herein, in "substituted" or "unsubstituted", the term "substituted" means that at least one hydrogen in the group is re-coordinated with a hydrocarbon group, a hydrocarbon derivative group, a halogen or a cyano group (-CN). The term "unsubstituted" means that at least one hydrogen in the group is not re-coordinated with a hydrocarbon group, a hydrocarbon derivative group, a halogen or a cyano group (-CN). Examples of hydrocarbon groups or hydrocarbon derivative groups may include C1 to C20 alkyl, C2 to C20 alkenyl, C2 to C20 alkynyl, C6 to C20 aryl, C5 to C20 heteroaryl, C1 to C20 alkylamino, C6 to C20 arylamino, C6 to C20 heteroarylamino, C6 to C20 arylheteroarylamino, etc., but are not limited thereto.

[0045] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0046] Embodiment 1:

[0047]

[0048] The synthesis method of compound 1 is as follows:

[0049]

[0050] Under nitrogen protection, compound 1-a (1eq, 10g, 445.9g / mol, 22.43mmol) and compound 1-b (1.1eq, 9.26g, 375.28g / mol, 24.67mmol) were dissolved in 200mL toluene, and palladium acetate (0.25g, 224.51g / mol, 1.12mmol), X-phos (0.26g, 476.72g / mol, 1.12mmol), potassium carbonate (9.30g, 138.21g / mol, 67.28mmol) were added, and then 100mL of ethanol and 50mL of water were added. The reaction was stirred at 82°C overnight and the reaction progress was monitored by HPLC.

[0051] After the reaction of compound 1-a was completed by HPLC monitoring, the reaction was stopped, the reaction solution was cooled to room temperature, 60 mL of water was added, stirred for 20 min, and filtered to obtain a filter cake. The filter cake was rinsed twice with water and ethanol and then dried at 80°C in vacuum for 6 hours. The dried filter cake was added to a 250 mL three-necked flask, 100 mL of o-dichlorobenzene was added, and heated to 120°C to completely dissolve the solid. After complete dissolution, the filtrate was passed through a silica gel and activated carbon funnel while hot to obtain a filtrate. The filtrate naturally cooled to room temperature. After a white solid precipitated, the filter cake was filtered to obtain a filter cake. After two more recrystallization operations, the final target product compound 1 (6.38 g, 9.69 mmol, yield 43.2%) was obtained, ESI-MS (m / z) (M+): theoretical value 658.76, measured value 659.22, elemental analysis results (molecular formula C45H22D5N5O): theoretical value C, 82.05; H, 4.89; N, 10.63; O, 2.43; measured value C, 82.09; H, 4.85; N, 10.67; O, 2.39.

[0052] Embodiment 2:

[0053]

[0054] The synthesis method of compound 2 is as follows:

[0055]

[0056] The preparation method is basically the same as that in Example 1, except that compound 1-b is replaced by compound 2-b to obtain the final target product compound 2 with a yield of 41.5%, ESI-MS (m / z) (M+): theoretical value 710.83, measured value 711.34, elemental analysis results (molecular formula C49H22D7N5O): theoretical value C, 82.79; H, 5.10; N, 9.85; O, 2.25; measured value C, 82.73; H, 5.17; N, 9.80; O, 2.30.

[0057] Embodiment 3:

[0058]

[0059] The synthesis method of compound 3 is as follows:

[0060]

[0061] The preparation method is basically the same as that in Example 1, except that compound 1-b is replaced by compound 3-b to obtain the final target product compound 3 with a yield of 45.6%. ESI-MS (m / z) (M+): theoretical value 710.83, measured value 711.21, elemental analysis results (molecular formula C49H22D7N5O): theoretical value C, 82.79; H, 5.10; N, 9.85; O, 2.25; measured value C, 82.83; H, 5.06; N, 9.89; O, 2.22.

[0062] Embodiment 4:

[0063]

[0064] The synthesis method of compound 8 is as follows:

[0065]

[0066] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 4-a to obtain the final target product compound 8 with a yield of 51.6%, ESI-MS (m / z) (M+): theoretical value 666.81, measured value 667.25, elemental analysis results (molecular formula C45H14D13N5O): theoretical value C, 81.05; H, 6.04; N, 10.50; O, 2.40; measured value C, 81.09; H, 6.00; N, 10.57; O, 2.34.

[0067] Embodiment 5:

[0068]

[0069] The synthesis method of compound 10 is as follows:

[0070]

[0071] The preparation method is basically the same as that in Example 1, except that compound 1-b is replaced by compound 5-b to obtain the final target product compound 10 with a yield of 44.7%, ESI-MS (m / z) (M+): theoretical value 784.91, measured value 783.98, elemental analysis results (molecular formula C55H28D5N5O): theoretical value C, 84.16; H, 4.88; N, 8.92; O, 2.04; measured value C, 84.10; H, 4.94; N, 8.90; O, 2.06.

[0072] Embodiment 6:

[0073]

[0074] The synthesis method of compound 18 is as follows:

[0075]

[0076] The preparation method is basically the same as that in Example 1, except that compound 1-b is replaced by compound 6-b, and the final target product compound 18 is obtained with a yield of 38.5%, ESI-MS (m / z) (M+): theoretical value 786.93, measured value 787.83, elemental analysis results (molecular formula C55H26D7N5O): theoretical value C, 83.95; H, 5.12; N, 8.90; O, 2.03; measured value C, 83.97; H, 5.10; N, 8.84; O, 2.09.

[0077] Embodiment 7:

[0078]

[0079] The synthesis method of compound 24 is as follows:

[0080]

[0081] The preparation method is basically the same as that in Example 1, except that compound 1-b is replaced by compound 7-b to obtain the final target product compound 24 with a yield of 40.8%, ESI-MS (m / z) (M+): theoretical value 786.93, measured value 787.35, elemental analysis results (molecular formula C55H26D7N5O): theoretical value C, 83.95; H, 5.12; N, 8.90; O, 2.03; measured value C, 83.99; H, 5.08; N, 8.85; O, 2.08.

[0082] Embodiment 8:

[0083]

[0084] The synthesis method of compound 32 is as follows:

[0085]

[0086] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 8-a to obtain the final target product compound 32 with a yield of 50.8%, ESI-MS (m / z) (M+): theoretical value 734.86, measured value 735.60, elemental analysis results (molecular formula C51H26D5N5O): theoretical value C, 83.36; H, 4.94; N, 9.53; O, 2.18; measured value C, 83.30; H, 4.99; N, 9.53; O, 2.18.

[0087] Embodiment 9:

[0088]

[0089] The synthesis method of compound 34 is as follows:

[0090]

[0091] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 9-a, and compound 1-b is replaced by compound 9-b, to obtain the final target product compound 34 with a yield of 37.4%, ESI-MS (m / z) (M+): theoretical value 786.93, measured value 787.19, elemental analysis results (molecular formula C55H26D7N5O): theoretical value C, 83.95; H, 5.12; N, 8.90; O, 2.03; measured value C, 83.98; H, 5.16; N, 8.86; O, 2.00.

[0092] Embodiment 10:

[0093]

[0094] The synthesis method of compound 41 is as follows:

[0095]

[0096] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 10-a, and compound 1-b is replaced by compound 10-b, to obtain the final target product compound 41 with a yield of 35.8%, ESI-MS (m / z) (M+): theoretical value 861.01, measured value 861.55, elemental analysis results (molecular formula C61H32D5N5O): theoretical value C, 85.09; H, 4.92; N, 8.13; O, 1.86; measured value C, 85.04; H, 4.97; N, 8.17; O, 1.82.

[0097] Embodiment 11:

[0098]

[0099] The synthesis method of compound 65 is as follows:

[0100]

[0101] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 11-a to obtain the final target product compound 65 with a yield of 48.9%, ESI-MS (m / z) (M+): theoretical value 734.86, measured value 735.41, elemental analysis results (molecular formula C51H26D5N5O): theoretical value C, 83.36; H, 4.94; N, 9.53; O, 2.18; measured value C, 83.30; H, 5.00; N, 9.56; O, 2.14.

[0102] Embodiment 12:

[0103]

[0104] The synthesis method of compound 66 is as follows:

[0105]

[0106] The preparation method is basically the same as that in Example 1, except that compound 1-a is replaced by compound 12-a to obtain the final target product compound 66 with a yield of 50.6%. ESI-MS (m / z) (M+): theoretical value 734.86, measured value 735.22, elemental analysis results (molecular formula C51H26D5N5O): theoretical value C, 83.36; H, 4.94; N, 9.53; O, 2.18; measured value C, 83.39; H, 4.91; N, 9.58; O, 2.12.

[0107] Material property test:

[0108] The thermal weight loss temperature Td and melting point Tm of compounds 1, 2, 3, 8, 10, 18, 24, 32, 34, 41, 65 and 66 of the present invention were tested. The test results are shown in Table 1 below.

[0109] Note: Thermogravimetric temperature Td is the temperature at which the weight loss is 5% in a nitrogen atmosphere, and is measured on a TGA N-1000 thermogravimetric analyzer with a nitrogen flow rate of 10 mL / min. The melting point Tm is measured by differential scanning calorimetry (DSC, Shinco DSC N-650) with a heating rate of 10°C / min.

[0110] Table 1:

[0111] project Material Td / ℃ Tm / ℃ Embodiment 01 1 477.67 304.33 Embodiment 02 2 463.41 317.52 Embodiment 03 3 492.50 277.18 Embodiment 04 8 485.71 328.41 Embodiment 05 10 511.65 262.56 Embodiment 06 18 475.26 235.35 Embodiment 07 24 503.22 289.49 Embodiment 08 32 524.58 309.58 Embodiment 09 34 460.46 247.17 Example 10 41 478.34 303.44 Embodiment 11 65 484.62 265.06 Example 12 66 508.07 317.48

[0112] It can be seen from the above data that the compounds synthesized in the present invention have excellent thermal stability, which means that the compounds conforming to the general structural formula of the present invention all have excellent thermal stability and can meet the requirements for the use of organic electroluminescent materials.

[0113] Device performance test:

[0114] Application Example 1:

[0115] ITO was used as the reflective layer anode substrate material, and its surface was treated with water, acetone, and N2 plasma in sequence;

[0116] On top of the ITO anode substrate, 10 nm of HT-1 doped with 5% HAT-CN was deposited to form a hole injection layer (HIL);

[0117] 100 nm of HT-1 was evaporated on the hole injection layer (HIL) to form the first hole transport layer (HTL);

[0118] Vacuum evaporation of GP on the first hole transport layer (HTL) to form a second hole transport layer (GPL) with a thickness of 30 nm;

[0119] Compound 1 and G1 designed by the present invention were co-evaporated at a mass ratio of 5:5 as green light host materials, and GD-1 was evaporated as a doping material (the amount of GD-1 was 8% of the total mass of compound 1 and G1) on the second hole transport layer (GPL) to form a light-emitting layer with a thickness of 30 nm;

[0120] HB-1 was evaporated onto the light-emitting layer to obtain a hole blocking layer (HBL) with a thickness of 20 nm;

[0121] ET-1 and LiQ were co-evaporated onto the hole blocking layer (HBL) in a ratio of 5:5 to obtain an electron transport layer (ETL) with a thickness of 30 nm;

[0122] Magnesium (Mg) and silver (Ag) were mixed and evaporated on the electron transport layer (ETL) in a ratio of 9:1 to form an electron injection layer (EIL) with a thickness of 50 nm;

[0123] Thereafter, silver (Ag) is evaporated onto the electron injection layer to form a cathode with a thickness of 100 nm, and a DNTPD with a thickness of 50 nm is deposited on the cathode sealing layer. In addition, the cathode surface is sealed with a UV curable adhesive and a sealing film (seal cap) containing a dehumidifier to protect the organic electroluminescent device from being affected by oxygen or moisture in the atmosphere. Thus, an organic electroluminescent device is prepared.

[0124]

[0125] Application Example 2-12

[0126] Compounds 2, 3, 8, 10, 18, 24, 32, 34, 41, 65, and 66 in Examples 2-12 of the present invention are used to replace Compound 1 as green light host materials, and other parts are consistent with Application Example 1, thereby preparing organic electroluminescent devices of Application Examples 2-12.

[0127] Comparative Examples 1-3:

[0128] The difference from Application Example 1 is that GH-1, GH-2 and GH-3 in CN112079824A are used instead of Compound 1 as the green light host material, and the rest is the same as Application Example 1.

[0129] The characteristics of the organic electroluminescent device manufactured in the above application example and the organic electroluminescent device manufactured in the control example are that at a current density of 10 mA / cm 2 The results were shown in Table 2.

[0130] Table 2:

[0131]

[0132] As shown in Table 2 above, when the compounds of the present invention are applied to organic electroluminescent devices, at the same current density, the luminous efficiency is greatly improved, the starting voltage of the device is reduced, the power consumption of the device is relatively reduced, and the life of the device is correspondingly increased.

[0133] The organic electroluminescent devices prepared in the control examples 1-3 and the application examples 1-5 were respectively subjected to luminescence life tests to obtain the luminescence life T97% data (the time when the luminescence brightness decreases to 97% of the initial brightness). The test equipment was a TEO luminescent device life test system. The results are shown in Table 3:

[0134] Table 3:

[0135]

[0136] It can be seen from Table 3 above that when the compound of the present invention is applied to an organic electroluminescent device, the service life is greatly improved at the same current density, and the compound has broad application prospects.

Claims

1. A compound containing carbazole, characterized in that Its structural formula is shown below: R1-R2 are each independently hydrogen or deuterium; L is a single bond; The R3 is selected from p and n are independently 0, 1, 2, 3, and 4.

2. A carbazole-containing compound according to claim 1, characterized in that: It is any one of the following compounds:

3. An organic electroluminescent device, characterized in that: The invention comprises a first electrode, a second electrode and an organic layer formed between the first electrode and the second electrode, wherein the organic layer comprises a hole injection layer, a first hole transport layer, a second hole transport layer, a light-emitting layer, a hole blocking layer, an electron transport layer and an electron injection layer; the light-emitting layer comprises the compound according to any one of claims 1 to 2, and the light-emitting layer further comprises at least one of the following compounds G1 to G28, G30, G32 and G47 to G56:

4. An electronic display device, characterized in that: Contains the organic electroluminescent device as claimed in claim 3.

5. An OLED lighting device, characterized in that: Contains the organic electroluminescent device as claimed in claim 3.

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