Triazine compound and organic electroluminescent device thereof

Abstract

The invention belongs to the technical field of organic electroluminescent materials, and particularly relates to a triazine compound and an organic electroluminescent device thereof. The triazine compound provided by the invention has good electron transport performance, triazine is connected with a meta-substituted benzene ring, the other two substituents of the meta-substituted benzene ring are biphenyl, and at least one benzene ring of the biphenyl contains at least one nitrogen atom. The organic semiconductor material has good planarity and appropriate LUMO energy level, the good planarity can increase the mobility of electrons, the appropriate LUMO energy level can reduce the injection barrier of carriers, the voltage of a device can be reduced, the efficiency of the device can be improved, and the service life of the device can be prolonged.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic electroluminescent materials, and particularly relates to a triazine compound and an organic electroluminescent device thereof. BACKGROUND

[0002] As the core of the third generation of display technology, organic light-emitting diodes (OLED) have been widely used in small and medium-sized display fields such as smart phones and notebook computers due to the advantages of self-luminescence, high contrast, low energy consumption and flexibility, and are accelerating the penetration into large-sized markets such as televisions and vehicle displays. In 2024, OLEDs first surpassed liquid crystal displays (LCDs) in small and medium-sized panel shipments, marking a key stage in the industrialization process. With domestic panel manufacturers such as Jingdongfang and Huaxingguangbo investing in the construction of 8.6-generation AMOLED production lines, the application scenarios of OLEDs are rapidly expanding from mobile devices to large-sized display fields, which puts forward higher requirements on the performance of materials: higher electron mobility to match the carrier transport requirements of large-sized devices, better film-forming properties to achieve uniform light emission, and lower driving voltage to improve energy efficiency and endurance.

[0003] In the multi-layer device structure of OLED (anode / hole transport layer / light-emitting layer / electron transport layer / cathode), the electron transport layer (ETL) plays a key role in regulating the injection and transport of electrons from the cathode to the light-emitting layer, and its performance directly affects the light-emitting efficiency, driving voltage and service life of the device. The currently widely used traditional ETL material such as Alq3 (8-hydroxyquinoline aluminum) has an electron mobility of only 10 -6 cm 2 / (V·s) order, which is much lower than that of hole transport materials (10 -3 -10 -4 cm 2 / (V·s)), resulting in a serious imbalance in carrier transport. This mobility gap causes multiple problems: insufficient electron injection and transport efficiency, which causes the recombination region to be biased towards the cathode side, uneven distribution of excitons and increased non-radiative recombination, which reduces the light-emitting efficiency; increasing the driving voltage to compensate for the electron transport defect not only increases the energy consumption but also accelerates the aging of the device. Therefore, developing an electron transport layer material with high electron mobility is a key path to achieving high efficiency, long service life and low voltage driving of OLED devices and promoting their comprehensive expansion in downstream applications. SUMMARY

[0004] To solve the problems in the background art, the application provides a triazine compound having the following general formula I: ; One or two of X1, X2 and X3 are N, and the others are CH; one or two of Y1, Y2, Y3is N, and the others are CH; Ar1, Ar2are each independently selected from the group consisting of substituted or unsubstituted C6-C 30 aryl or C3-C 30 heteroaryl; R1, R2are each independently selected from the group consisting of hydrogen, deuterium, cyano, C1-C 30 chain alkyl, C1-C 30 cycloalkyl, C6-C 30 aryl, C3-C 30 heteroaryl; m, n are each independently selected from 1 to the maximum number of substituents on the ring; when substituents are present, the substituents are each independently selected from the group consisting of deuterium, fluorine, cyano, C6-C 18 aryl, C5-C 18 heteroaryl, the heteroatom of the heteroaryl being selected from N, O, S.

[0005] As a preferred embodiment of the present application, Ar1, Ar2are each independently selected from the group consisting of substituted or unsubstituted C6-C 18 aryl or C3-C 18 heteroaryl.

[0006] As a preferred embodiment of the present application, Ar1, Ar2are each independently selected from the group consisting of substituted or unsubstituted phenyl or biphenyl.

[0007] As a preferred embodiment of the present application, R1, R2are each independently selected from the group consisting of hydrogen, deuterium, cyano, methyl, cyclohexyl, phenyl, pyridyl.

[0008] As a preferred embodiment of the present application, when substituents are present, the substituents are each independently selected from the group consisting of deuterium, fluorine, cyano, phenyl, pyridyl.

[0009] As a preferred embodiment of the present application, the specific structure of the compound is as follows: ; ; ; ; ; ; ; ; ; ; ;

[0010] As a preferred embodiment of the present application, the electron transport layer contains the above-mentioned triazine compound.

[0011] As a preferred embodiment of the present application, the organic electroluminescent device is used for manufacturing display devices, lighting sources, signal lights, and signs, including mobile phone display screens, computer display screens, television display screens, smart watch display screens, smart car display panels, and VR or AR helmet display screens.

[0012] The beneficial effects of the present application are as follows: The triazine compound provided by the present application can significantly reduce the lowest unoccupied molecular orbital (LUMO) energy level of the molecule due to the high electronegativity of the N atom, which can promote efficient injection of electrons by matching the LUMO energy level of the light-emitting layer. In addition, the N atom can form intramolecular hydrogen bonds with the hydrogen on the adjacent aromatic ring, such as the N atom on the triazine ring and the hydrogen on the A ring, the N atom on the B ring and the hydrogen on the C ring, the N atom on the D ring and the hydrogen on the A ring, the N atom on the D ring and the hydrogen on the E ring, etc., which can greatly improve the electron mobility and ensure the rapid transmission of electrons in the electron transport layer. At the same time, the connection of the C ring and the E ring with the A ring at the adjacent position will produce a certain steric hindrance, forcing the molecule to adopt a more random arrangement, which can inhibit the excessive crystallization of the material during the evaporation process, thus facilitating the formation of smooth, dense, and amorphous thin films during the evaporation process, thereby improving the stability of the device.

[0013] The triazine compound provided by the present application has the synergistic effects of efficient electron transport, precise carrier recombination, excellent thermal stability, and film-forming property, which can reduce the problems of "material degradation, interface defects, and non-radiative loss caused by carrier imbalance" from the root, greatly extend the working life of the OLED device, and meet the stringent requirements of commercialization for long life. DETAILED DESCRIPTION

[0014] The technical solutions of the present application will be described below in conjunction with the embodiments, and obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0015] ​​Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer were followed. Reagents and instruments whose manufacturers are not specified were all commercially available products. Some reaction compounds were purchased from a supplier (Zhengzhou Alpha Chemical Co., Ltd.), while some compounds that could not be directly purchased were prepared from commercially available raw materials through simple reactions. Percentages refer to mass percentages, and temperatures are in degrees Celsius (°C). The principles, procedures, conventional post-treatments, silica gel column chromatography, recrystallization purification, and other techniques of this method are well-known to those skilled in the art and can be fully implemented to obtain the target product.

[0016] Preparation Examples Example 1: Preparation of Compound 10 ; Synthesis of Compound 10: 10⁻¹ (5.23 g, 15 mmol) and 10⁻² (7.69 g, 15 mmol) were completely dissolved in tetrahydrofuran (THF) (100 mL), and 2 M potassium carbonate aqueous solution (60 mL) and tetra-(triphenylphosphine)palladium (Pd(PPh₃)₄) (1.2 g, 1.0 mmol) were added. The mixture was heated and stirred for 6 h. The mixture was then cooled to room temperature to complete the reaction. After removing the potassium carbonate solution, the solid was filtered off and washed once with ethanol. Compound 10 (9.75 g, 93%), MS: 698.97.

[0017] Example 2: Preparation of Compound 20 ; Compound 20 was synthesized in the same way as compound 10, except that 20-1 was used instead of 10-1 and 20-2 was used instead of 10-2. MS: 796.69.

[0018] Example 3: Preparation of compound 30 ; Compound 30 was synthesized in the same way as compound 10, except that 20-1 was used instead of 10-1 and 30-1 was used instead of 10-2. MS: 783.64.

[0019] Example 4: Preparation of Compound 40 ; Compound 40 was synthesized in the same way as compound 10, except that 10-1 was replaced by 40-1 and 10-2 was replaced by 40-2. MS: 783.79.

[0020] Example 5: Preparation of Compound 50 ; Compound 50 was synthesized in the same way as compound 10, except that 10-1 was replaced with 50-1 and 10-2 was replaced with 50-2. MS: 773.45.

[0021] Example 6: Preparation of Compound 60 ; Compound 60 was synthesized in the same way as compound 10, except that 10-3 was replaced by 60-1 and 10-4 was replaced by 20-4. MS: 788.81.

[0022] Example 7: Preparation of Compound 70 ; Compound 70 was synthesized in the same way as compound 10, except that 10-1 was replaced by 70-1 and 10-2 was replaced by 70-2. MS: 863.78.

[0023] Example 8: Preparation of Compound 80 ; Compound 80 was synthesized in the same way as compound 10, except that 70-1 was used instead of 10-1 and 80-1 was used instead of 10-2. MS: 940.84.

[0024] Example 9: Preparation of Compound 90 ; Compound 90 was synthesized using the same method as compound 10, except that 10-1 was replaced with 90-1. MS: 694.92.

[0025] Example 10: Preparation of Compound 100 ; Compound 100 was synthesized in the same way as compound 10, except that 10-1 was replaced by 100-1 and 10-3 was replaced by 100-2. MS: 935.83.

[0026] Example 11: Preparation of compound 110 ; Compound 110 was synthesized in the same way as compound 10, except that 10⁻¹ was replaced with 10⁻¹ and 10⁻² was replaced with 30⁻¹. MS: 860.72.

[0027] Example 12: Preparation of Compound 120 ; Compound 120 was synthesized in the same way as compound 10, except that 120-1 was replaced by 10-1 and 120-2 was replaced by 10-2. MS: 795.78.

[0028] Example 13: Preparation of Compound 130 ; Compound 130 was synthesized in the same way as compound 10, except that 130-1 was replaced with 10-1 and 50-2 was replaced with 10-2. MS: 858.74.

[0029] Example 14: Preparation of Compound 140 ; Compound 140 was synthesized in the same way as compound 10, except that 130-1 was used instead of 10-1 and 140-1 was used instead of 10-2. MS: 887.69.

[0030] Example 15: Preparation of Compound 150 ; Compound 150 was synthesized in the same way as compound 10, except that 150-1 was replaced with 10-1 and 70-2 was replaced with 10-2. MS: 693.92.

[0031] Example 16: Preparation of Compound 160 ; Compound 160 was synthesized in the same way as compound 10, except that 150-1 was used instead of 10-1 and 160-1 was used instead of 10-2. MS: 694.95.

[0032] Example 17: Preparation of Compound 170 ; Compound 170 was synthesized in the same way as compound 10, except that 170-1 was used instead of 10-1. MS: 769.78.

[0033] Example 18: Preparation of Compound 180 ; Compound 180 was synthesized in the same way as compound 10, except that 180-1 was replaced by 10-1 and 180-2 was replaced by 10-2. MS: 616.61.

[0034] Example 19: Preparation of Compound 190 ; Compound 190 was synthesized in the same way as compound 10, except that 180-1 was used instead of 10-1 and 30-1 was used instead of 10-2. MS: 617.84.

[0035] Example 20: Preparation of Compound 200 ; Compound 200 was synthesized in the same way as compound 10, except that 200-1 was used instead of 10-1 and 200-2 was used instead of 10-2. MS: 774.81.

[0036] Example 21: Preparation of compound 210 ; Compound 210 was synthesized in the same way as compound 10, except that 210-2 replaced 10-1 and 50-2 replaced 10-2. MS: 692.97.

[0037] Example 22: Preparation of compound 220 ; Compound 220 was synthesized in the same way as compound 10, except that 210-1 was used instead of 10-1 and 220-1 was used instead of 10-2. MS: 693.67.

[0038] Example 23: Preparation of compound 230 ; Compound 230 was synthesized in the same way as compound 10, except that 10-1 was replaced by 230-1 and 10-2 was replaced by 70-2. MS: 770.77.

[0039] Example 24: Preparation of compound 240 ; Compound 240 was synthesized in the same way as compound 10, except that 10-1 was replaced by 230-1 and 10-2 was replaced by 160-2. MS: 771.73.

[0040] In addition, it should be noted that other compounds in this application can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0041] Device Examples Preparation of Example 1: A glass substrate coated with a 1000 Å thick ITO (indium tin oxide) film was immersed in distilled water containing a cleaning agent and ultrasonically cleaned. After cleaning the ITO for 30 minutes, ultrasonic cleaning was repeated twice for 10 minutes each time with distilled water. The substrate was then ultrasonically cleaned with isopropanol, acetone, and methanol solvents, dried, and transferred to a plasma cleaner for 5 minutes before being transferred to a vacuum deposition unit. On an ITO transparent electrode, compound [HI] was thermally vacuum-deposited to a thickness of 100 Å to form a hole injection layer; compound [HT] was vacuum-deposited to 800 Å on the hole injection layer to form a hole transport layer; compounds [BH] and [BD] were vacuum-deposited to a thickness of 200 Å on the hole transport layer at a ratio of 97:3 to form a light-emitting layer; compounds 10 and [LiQ] (lithium quinoline) were vacuum-deposited to the light-emitting layer at a ratio of 1:1 to form an electron transport layer with a thickness of 300 Å; yttrium (Yb) and magnesium silver (1:9) were sequentially deposited on the electron transport layer to thicknesses of 10 Å and 1000 Å, respectively, to form a cathode. The vacuum level during deposition was maintained at 1 × 10⁻⁶. -7 Up to 5×10 -8 Entrust.

[0042] Preparation of Examples 2-24: When forming the electron transport layer, the organic electroluminescent device was prepared by replacing compound 10 in Example 1 with the compounds shown in Table 1, and using the same method as in Example 1.

[0043] Preparation of Comparative Examples 1-2: The organic electroluminescent device was prepared using the same method as in Example 1, except that the comparative compound ref-1 or compound ref-2 was used instead of compound 10 in Example 1 when forming the electron transport layer.

[0044] The structures of the compounds used in the above preparation process are as follows: ; The LUMO values ​​of each compound in Table 1 were calculated using Gaussian calculation software. The materials of each compound in Table 1 were fabricated into single-charge devices, and their electron mobility was determined by SCLC method. .

[0045] At 10mA / cm 2 The drive voltage and current efficiency of the device embodiments and comparative examples were determined at a current density of 50 mA / cm². 2The time required for the brightness to decrease to 97% of the initial brightness at a given current density (LT97) was measured. Driving voltage and current efficiency were tested using an IVL (current-voltage-brightness) testing system (Suzhou Fosstar Scientific Instruments Co., Ltd.). The lifetime testing system was the OLED lifetime testing system from Suzhou Fosstar Scientific Instruments Co., Ltd. The blue light index BI = E / CIEy represents the exponent of the effective efficiency of the blue light device, where E refers to current efficiency and CIEy refers to the ordinate color point obtained by inputting the device's emission half-peak wavelength into the CIE1930 software. The results are shown in Table 2 below.

[0046] As shown in Table 2, the luminous efficiency and lifetime of Examples 1-24 of the present invention are improved compared with Comparative Examples 1 and 2. This is because the series of compounds provided by the present invention have suitable LUMO energy levels (see Table 1), which can reduce the carrier injection barrier, thereby reducing the device voltage and improving the device efficiency and lifetime. In addition, as shown in Table 1, the series of compounds provided by the present invention have higher electron mobility compared with ref-1 and ref-2. This may be due to the presence of more intramolecular hydrogen bonds in the series of compounds provided by the present invention, resulting in stronger molecular planarity and improved electron mobility. Higher electron mobility is beneficial for reducing device voltage and improving current efficiency (see Table 2).

[0047] The above embodiments only list the effect data of devices made from a portion of the compounds. This is a representative sampling test. Based on the experimental data, the overall data is not significantly different and can represent the effects of other unlisted compounds.

[0048] The applicant declares that the organic electroluminescent materials and organic electroluminescent devices of the present invention are illustrated through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that the present invention can have many modifications and variations without departing from the spirit and scope of the invention.

Claims

1. A triazine compound, characterized in that, It has the structure shown in general formula I: ； One or two of X1, X2, and X3 are N, and the others are CH; One or two of Y1, Y2, and Y3 are N, and the others are CH; Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6~C6. 30 Aryl or C3~C 30 Mixed aromatics; R1 and R2 are each independently selected from hydrogen, deuterium, cyano, and C1~C2. 30 Chain alkyl, C1~C 30 cycloalkyl, C6~C 30 Aryl, C3~C 30 Mixed aromatics; m and n are each independently selected from 1 to the largest substitution base number in their respective rings; When substituents are present, each substituent is independently selected from deuterium, fluorine, cyano, C6~C. 18 Aryl, C5~C 18 The heteroatom of the heteroaryl group is selected from N, O, and S.

2. The triazine compound according to claim 1, characterized in that, Ar1 and Ar2 are each independently selected from substituted or unsubstituted C6~C6. 18 Aryl or C3~C 18 Mixed aromatic compounds.

3. The triazine compound according to claim 2, characterized in that, Ar1 and Ar2 are each independently selected from substituted or unsubstituted phenyl or biphenyl.

4. The triazine compound according to claim 1, characterized in that, R1 and R2 are each independently selected from hydrogen, deuterium, cyano, methyl, phenyl, and pyridyl.

5. The triazine compound according to claim 1, characterized in that, When substituents are present, each substituent is independently selected from deuterium, fluorine, cyano, phenyl, and pyridyl.

6. The triazine compound according to claim 1, characterized in that, The specific structure of this compound is as follows: ； ； ； ； ； ； ； ； ； ； ； ； 。 7. An organic electroluminescent device, comprising an electron transport layer, characterized in that, The electron transport layer contains a triazine compound as described in any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: This organic electroluminescent device is used to manufacture display devices, lighting sources, signal lights, and signs. The display devices include mobile phone displays, computer displays, television displays, smartwatch displays, smart car display panels, and VR or AR helmet displays.

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