CN116135853A - A compound containing triazine and dibenzo five-membered ring structure and its application - Google Patents

Abstract

The invention discloses a compound containing triazine and dibenzo five-membered ring structures, which has a structure shown in a general formula (1):

in the general formula (1), R ₁ 、R ₂ Each independently is represented by phenyl, deuterated phenyl, hydrogen, or deuterium; x represents an oxygen or sulfur atom; a is represented by the structure shown in the general formula (2)In the formula (2), Z ₀ 、Z ₁ 、Z ₂ 、Z ₃ 、Z ₄ 、Z ₅ 、Z ₆ Each occurrence is independently denoted as C-H or C-D. The compound is used for an organic electroluminescent device, has the characteristics of low voltage, low starting voltage and high efficiency, and can be used as a main body substitute material with longer service life and longer high-temperature service life of the device.

Description

A compound containing triazine and dibenzo pentacyclic structure and its application

Technical Field

The invention relates to the field of semiconductor technology, in particular to a compound containing triazine and dibenzo pentacyclic structures and application thereof.

Background Art

There may be a hole transport region between the anode and the light-emitting layer of the organic electroluminescent device, and there may be an electron transport region between the light-emitting layer and the cathode. Holes from the anode may migrate to the light-emitting layer through the hole transport region, and electrons from the cathode may migrate to the light-emitting layer through the electron transport region, where holes and electrons recombine in the light-emitting layer and generate excitons. Based on the spin coupling effect of heavy metal atoms, the organometallic compound material can directly transition from triplet emission energy to the ground state, and theoretically achieve an internal quantum yield of 100%.

Nevertheless, for triplet-luminescent phosphorescent OLEDs, there is still a need for improvement in device voltage, current efficiency and life. The performance of the host material in the light-emitting layer usually affects the above-mentioned key properties of the organic electroluminescent device to a large extent. According to the prior art, the compounds used as host materials usually contain triazine groups. When the existing triazine derivatives are used as host materials, there is a need for improvement in device voltage, current efficiency, especially in turn-on voltage and device life. The present invention provides a host replacement material with low voltage, high efficiency, long life, especially low turn-on voltage and long high-temperature life.

For phosphorescent OLED, there is usually an imbalance between holes and electrons in the light-emitting layer, and the device efficiency roll-off is serious under high current density. The present invention also provides a combination of two host materials, which can effectively solve the above-mentioned drawbacks.

Summary of the invention

In view of the above problems existing in the prior art, the applicant of the present invention provides a compound containing triazine and dibenzo pentacyclic structure and its application. The compound of the present invention is used in organic electroluminescent devices, has the characteristics of low voltage and low turn-on voltage, and high efficiency, and can be used as a main body replacement material for longer device life and longer high temperature life.

The technical solution of the present invention is as follows:

A compound containing triazine and dibenzo pentacyclic structure, wherein the structure of the compound is shown in general formula (1):

In the general formula (1), R ₁ and R ₂ are independently phenyl, deuterated phenyl, hydrogen or deuterium;

X represents an oxygen or sulfur atom;

A is represented by the structure shown in general formula (2):

A and Z ₃ , Z ₄ , Z ₅ or Z ₆ are connected by a single bond;

Each occurrence of Z ₀ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , and Z ₆ is independently represented by CH or CD.

In a preferred embodiment, the structure of the compound is represented by any one of the general formulas (3-1) to (3-4):

A, X, R ₁ , R ₂ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ and Z ₆ have the same meanings as defined above.

In a preferred embodiment, the structure of the compound is represented by any one of the general formulas (4-1) to (4-4):

A, X, Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ and Z ₆ have the same meanings as defined above.

In a preferred embodiment, the compounds of the general formulae (4-1) to (4-2) contain at least one aromatic ring which is substituted with deuterium, and the aromatic ring is a benzene ring, a carbazole ring or a dibenzofuran.

In a preferred embodiment, the structure of the compound is represented by any one of the general formulas (5-1) to (5-2):

A, X, R ₁ , R ₂ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ and Z ₆ have the same meanings as defined above.

In a preferred embodiment, the structure of the compound is represented by any one of the general formulas (5-3) to (5-4):

A, X, R ₁ , R ₂ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ and Z ₆ have the same meanings as defined above.

In a preferred embodiment, the structure of the compound is represented by any one of the general formulas (6-1) to (6-6):

In general formula (6-1) to general formula (6-6), R ₁ and R ₂ are independently phenyl, deuterated phenyl, hydrogen or deuterium; X is oxygen or sulfur atom; A is a structure represented by general formula (2):

A is connected to Z ₃ , Z ₄ , Z ₅ or Z ₆ via a single bond; each occurrence of Z ₀ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ and Z ₆ is independently represented by CH or CD.

In a preferred embodiment, the specific structure of the compound is any one of the following structures:

An organic electroluminescent device comprises a cathode, an anode and a functional layer, wherein the functional layer is located between the cathode and the anode, and at least one functional layer in the organic electroluminescent device contains the compound containing triazine and dibenzo pentacyclic structures.

Preferably, the functional layer comprises a light-emitting layer, and the light-emitting layer contains the compound containing triazine and dibenzopentacyclic structures.

Further preferably, the luminescent host material of the luminescent layer is a mixture of the compound containing triazine and dibenzo pentacyclic structure and any one or more of compounds GH-1 to GH-170, and the specific structures of the compounds GH-1 to GH-170 are:

Preferably, the functional layer comprises a hole blocking layer and/or an electron transport layer, and the hole blocking layer and/or the electron transport layer contain the compound containing triazine and dibenzopentacyclic structures.

A lighting or display element, comprising the organic electroluminescent device.

The beneficial technical effects of the present invention are:

The bridging mode between the carbazole group and the dibenzo pentacyclic ring in the compound provided by the present invention makes it have higher carrier mobility than the compound in the prior art, which helps to improve the overall performance of the device.

The compound provided by the present invention further introduces deuterium atoms in the side chain, and its application in the light-emitting layer helps to improve the efficiency roll-off problem of the device at high current density and increase the device life.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the structure of an OLED device in which the materials listed in the present invention are applied;

Among them, 1 is a transparent substrate layer, 2 is an anode layer, 3 is a hole injection layer, 4 is a hole transport layer, 5 is an electron blocking layer, 6 is a light-emitting layer, 7 is an electron transport layer, 8 is an electron injection layer, 9 is a cathode layer, and 10 is a CPL layer;

Figure 2 is the H NMR spectrum of compound 56.

DETAILED DESCRIPTION

The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

In the present invention, unless otherwise specified, HOMO means the highest occupied orbital of a molecule, and LUMO means the lowest unoccupied orbital of a molecule. In addition, in the present invention, HOMO and LUMO energy levels are expressed in absolute values, and the comparison between energy levels is also a comparison of the magnitude of their absolute values. Those skilled in the art know that the greater the absolute value of an energy level, the lower the energy of the energy level.

Any numerical range listed herein is intended to include all sub-ranges with the same numerical precision included in the listed range. For example, "1.0 to 10.0" means all sub-ranges (and including 1.0 and 10.0) included between the listed minimum value 1.0 and the listed maximum value 10.0, that is, all sub-ranges with a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0. Any maximum numerical limit listed herein is intended to include all smaller numerical limits included in this article, and any minimum numerical limit listed herein is intended to include all larger numerical limits included in this article. Therefore, the applicant reserves the right to modify this specification including the claims to clearly describe any sub-ranges falling within the scope clearly described herein.

In the accompanying drawings, the dimensions of layers and regions may be exaggerated for clarity. It will also be understood that when a layer or element is referred to as being "on" another layer or substrate, the layer or element may be directly on the other layer or substrate, or there may be intervening layers. In addition, it will be understood that when a layer is referred to as being "between" two layers, the layer may be the only layer between the two layers, or there may be one or more intervening layers. The same reference numerals throughout the text represent the same elements.

In the present invention, when describing electrodes and organic electroluminescent devices, as well as other structures, the words "upper", "lower", "top" and "bottom" used to indicate orientation only indicate the orientation in a certain state, and do not mean that the related structure can only exist in the orientation described; on the contrary, if the structure can change its position, such as inverted, the orientation of the structure will be changed accordingly. Specifically, in the present invention, the "bottom" or "lower" side of the electrode refers to the side of the electrode close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" or "upper" side.

Example 1: Synthesis of Compound 2:

Intermediate A-1 (1.0 mmol) was added to a bottle, followed by intermediate B-1 (1.1 mmol), saturated K ₂ CO ₃ solution (3.0 mmol), THF (25 mL) and Pd(PPh ₃ ) ₄ (0.1 mmol); refluxed for two days under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, extracted with dichloromethane (150 mL×3), and then dried with anhydrous sodium sulfate, filtered and concentrated. The obtained residue was purified by silica gel column chromatography to obtain compound 2; LC-MS: theoretical value: 716.26; measured value ([M+H]+): 717.42.

The synthesis of intermediate A-1:

Raw material a-1 (10.0 mmol), raw material b-1 (25.0 mmol), Pd(PPh ₃ ) ₄ (1.0 mmol), saturated aqueous K ₂ CO ₃ (50.0 mmol) solution and THF (60 mL) were added into the bottle in sequence. The mixture was refluxed overnight under nitrogen protection. After the reaction, saturated brine was added and the mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate and the concentrated residue was purified by silica gel column chromatography to obtain intermediate c-1. LC-MS: theoretical value: 443.10; measured value ([M+H]+): 444.15.

Add intermediate c-1 (6.0mmol), Pd(dba) ₂ (0.3mmol), S-Phos (0.6mmol), AcONa (15.0mmol), toluene (100mL) in sequence, and finally add diboric acid pinacol ester (10mmol), and reflux overnight under nitrogen protection. After the reaction is completed and the temperature is reduced to room temperature, ethyl acetate is added to dilute the reaction solution, which is then washed with saturated brine, and the organic phase is dried over anhydrous sodium sulfate. The crude product obtained by concentration is slurried (EA/PE=8:1) to obtain intermediate-A1; LC-MS: theoretical value: 525.22; measured value ([M+H]+): 526.37.

The synthesis of intermediate A-5:

Raw material-1 (10.0 mmol), raw material-2 (25.0 mmol), Pd(PPh ₃ ) ₄ (1.0 mmol), saturated aqueous K ₂ CO ₃ (50.0 mmol) solution and THF (60 mL) were added into the bottle in sequence. The mixture was refluxed overnight under nitrogen protection. After the reaction, saturated brine was added. The mixture was extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate. The concentrated residue was purified by silica gel column chromatography to obtain intermediate-1. LC-MS: theoretical value: 443.16; measured value ([M+H]+): 444.32.

Add intermediate-1 (6.0mmol), Pd(dba) ₂ (0.3mmol), S-Phos (0.6mmol), AcONa (15.0mmol), toluene (100mL) in sequence to the bottle, and finally add raw material 3 (10mmol), and reflux overnight under nitrogen protection. After the reaction is completed and the temperature is reduced to room temperature, ethyl acetate is added to dilute the reaction solution, which is then washed with saturated brine, and the organic phase is dried over anhydrous sodium sulfate. The crude product obtained by concentration is slurried (EA/PE=8:1) to obtain intermediate-A5; LC-MS: theoretical value: 521.27; measured value ([M+H]+): 522.35.

The preparation methods of intermediate A-2, intermediate A-3, intermediate A-4 and intermediate A-6 are the same as the preparation methods of intermediate A-1 or intermediate A-5 above, and can also be prepared by conventional synthetic means with reference to the methods described in the prior art.

The following target compound was synthesized by referring to the preparation process of Example 1; the reaction conditions were the same, except that the intermediate B and intermediate A listed in Table 1 below were used.

Table 1

The nuclear magnetic data of compound 56 are: ¹ H NMR (400 MHz, Chloroform-d) δ8.93 (d, 1H), 8.78-8.75 (m, 4H), 8.70-8.69 (d, 1H), 8.22-8.20 (d, 2H), 7.99-7.98 (m, 1H), 7.90-7.84 (m, 5H), 7.77-7.73 (m, 1H), 7.65-7.54 (m, 11H), 7.50-7.42 (m, 3H), 7.37-7.33 (m, 2H), 7.17-7.13 (m, 1H).

The following describes in detail the application effect of the OLED material synthesized by the present invention in the device through device examples 1-21 and device comparison examples 1-8. Compared with the device of device comparison examples 1-8, the device manufacturing process of device examples 1-21 of the present invention is exactly the same, and the same substrate material and electrode material are used, and the film thickness of the electrode material is also the same. The difference is that the light-emitting layer in the device is replaced.

Device Example 1

As shown in Figure 1, the transparent substrate layer 1 is a transparent PI film, and the anode layer 2 (ITO (15nm) / Ag (150nm) / ITO (15nm)) is washed, that is, the cleaning agent washing (SemiClean M-L20), pure water washing, drying, and then ultraviolet-ozone washing are performed in sequence to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, HT-1 and P-1 are evaporated on the anode layer 2 using a vacuum evaporation device as a hole injection layer 3, with a film thickness of 10nm, and a mass ratio of HT-1 to P-1 of 97:3. Then HT-1 is evaporated as a hole transport layer 4 with a thickness of 130nm. Then EB-1 is evaporated as an electron blocking layer 5 with a thickness of 40nm. After the above-mentioned electron blocking layer material is evaporated, the light-emitting layer 6 of the OLED light-emitting device is prepared, and its structure includes the compound 2 used in the OLED light-emitting layer 6 as the main material, GD-1 as the guest material, the mass ratio of compound 2 and GD-1 is 94:6, and the thickness of the light-emitting layer is 40nm. After the above-mentioned light-emitting layer 6, ET-1 and Liq are vacuum evaporated, the mass ratio of ET-1 and Liq is 1:1, the film thickness is 35nm, and this layer is the electron transport layer 7. On the electron transport layer 7, a LiF layer with a film thickness of 1nm is prepared by a vacuum evaporation device, and this layer is the electron injection layer 8. On the electron injection layer 8, a Mg:Ag electrode layer with a film thickness of 15nm is prepared by a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9. This layer is the cathode layer 9. On the cathode layer 9, CP-1 is vacuum evaporated as the CPL layer 10 with a thickness of 70nm. An organic electroluminescent device 1 is obtained.

Device Example 11

As shown in Figure 1, the transparent substrate layer 1 is a transparent PI film, and the anode layer 2 (ITO (15nm) / Ag (150nm) / ITO (15nm)) is washed, that is, the cleaning agent washing (SemiClean M-L20), pure water washing, drying, and then ultraviolet-ozone washing are performed in sequence to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, HT-1 and P-1 are evaporated on the anode layer 2 using a vacuum evaporation device as a hole injection layer 3, with a film thickness of 10nm, and a mass ratio of HT-1 to P-1 of 97:3. Then HT-1 is evaporated as a hole transport layer 4 with a thickness of 130nm. Subsequently, EB-1 is evaporated as an electron blocking layer 5 with a thickness of 40nm. After the above-mentioned electron blocking layer material is evaporated, the light-emitting layer 6 of the OLED light-emitting device is prepared, and its structure includes the compound 2 and GH-2 used in the OLED light-emitting layer 6 as the main materials, GD-1 as the guest material, the mass ratio of compound 2, GH-2, and GD-1 is 47:47:6, and the thickness of the light-emitting layer is 40nm. After the above-mentioned light-emitting layer 6, ET-1 and Liq are vacuum evaporated, the mass ratio of ET-1 and Liq is 1:1, the film thickness is 35nm, and this layer is the electron transport layer 7. On the electron transport layer 7, a LiF layer with a film thickness of 1nm is prepared by a vacuum evaporation device, and this layer is the electron injection layer 8. On the electron injection layer 8, a Mg:Ag electrode layer with a film thickness of 15nm is prepared by a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9. This layer is the cathode layer 9. On the cathode layer 9, CP-1 is vacuum evaporated as the CPL layer 10 with a thickness of 70nm. An organic electroluminescent device 1 is obtained.

The molecular structure formula of the relevant materials is shown below:

After the OLED light-emitting device is completed as described above, the anode and cathode are connected with a known driving circuit, and the voltage, current efficiency, luminescence spectrum and device life of the device are measured. The device examples and comparative examples prepared by the same method are shown in Table 3; the test results of the voltage, current efficiency and LT95 life of the obtained device at 20mA/ ^cm2 are shown in Tables 4-1 and 4-2.

Table 3

Table 4-1

Table 4-2

Note: Voltage, current efficiency and color coordinates are tested at a current density of 10mA/ ^cm2 using an IVL (current-voltage-luminance) test system (Suzhou Fushida Scientific Instrument Co., Ltd.); the life test system is the EAS-62C OLED device life tester from Japan System Technology Co., Ltd.; the device life LT95 refers to the time taken for the device brightness to decay to 95% of the initial brightness when the current density is 20mA/ ^cm2 ; the high-temperature device life LT95 refers to the time taken for the device brightness to decay to 95% of the initial brightness when the current density is 20mA/ ^cm2 and the temperature is 85℃; the start-up voltage refers to the driving voltage of the device when the device brightness is 1nit.

It can be seen from the device data results in Tables 4-1 and 4-2 that, compared with the device comparison examples, the organic light-emitting device of the present invention is improved in terms of device voltage, device efficiency and device life relative to OLED devices of known materials, especially the device's turn-on voltage and high-temperature life are significantly improved.

其中μ_m表示为器件的最大电流效率，μ₅₀表示驱动电流为50mA/cm²时器件的电流效率。

值越大，说明器件的效率滚降越严重，反之，说明器件在高电流密度下快速衰降的问题得到了控制。本发明测定了器件实施例1、2、3、4、5、6、7、9、10、11、12、13、21，器件比较例1-8所得器件的效率衰减系数

结果如表5示：In order to compare the efficiency attenuation of different devices at high current density, the efficiency attenuation coefficient of each device is defined

Where _μm represents the maximum current efficiency of the device, and _μ50 represents the current efficiency of the device when the driving current is 50mA/ ^cm2 .

The larger the value, the more serious the efficiency roll-off of the device. Conversely, it means that the problem of rapid attenuation of the device at high current density has been controlled. The present invention measures the efficiency attenuation coefficient of the device obtained in device embodiments 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 21 and device comparison examples 1-8.

The results are shown in Table 5:

Table 5

Device Embodiment Efficiency reduction coefficient φ Device Embodiment Efficiency reduction coefficient φ Example 1 0.230 Comparative Example 4 0.306 Example 2 0.249 Example 9 0.251 Example 3 0.235 Example 10 0.256 Example 4 0.226 Embodiment 11 0.158 Example 5 0.242 Example 12 0.177 Example 6 0.250 Example 13 0.172 Example 7 0.253 Embodiment 21 0.161 Comparative Example 1 0.332 Comparative Example 6 0.218 Comparative Example 2 0.326 Comparative Example 7 0.203 Comparative Example 3 0.337 Comparative Example 8 0.244 Comparative Example 5 0.214

It can be seen from the data in Table 5 that the organic light-emitting device prepared using the compound of the present invention has a smaller efficiency attenuation coefficient than that of the comparative example, indicating that the organic electroluminescent device prepared using the compound of the present invention can effectively reduce the efficiency roll-off of the device at high current density.

In summary, the above are only 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 in the protection scope of the present invention.

Claims (10)

1. A compound containing triazine and dibenzo pentacyclic structure, characterized in that the structure of the compound is as shown in general formula (1):

In the general formula (1), R ₁ and R ₂ are independently phenyl, deuterated phenyl, hydrogen or deuterium; X represents an oxygen or sulfur atom; A is represented by the structure shown in general formula (2):

A and Z ₃ , Z ₄ , Z ₅ or Z ₆ are connected by a single bond; Each occurrence of Z ₀ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , and Z ₆ is independently represented by CH or CD. 2. The compound according to claim 1, characterized in that the structure of the compound is represented by any one of the general formulas (3-1) to (3-4):

A, X, R ₁ , R ₂ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , and Z ₆ have the same meanings as defined in claim 1. 3. The compound according to claim 2, characterized in that the structure of the compound is represented by any one of the general formulas (4-1) to (4-4):

A, X, Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , and Z ₆ have the same meanings as defined in claim 1. 4. The compound according to claim 3, characterized in that the compound structure of the general formula (4-1) to (4-2) contains at least one aromatic ring that is substituted with deuterium, and the aromatic ring is a benzene ring, a carbazole ring or a dibenzofuran. 5. The compound according to claim 1, characterized in that the structure of the compound is represented by any one of the general formulas (5-1) to (5-2):

A, X, R ₁ , R ₂ , Z ₁ , Z ₂ , Z ₃ , Z ₄ , Z ₅ , and Z ₆ have the same meanings as defined in claim 1. 6. The compound according to claim 1, characterized in that the specific structure of the compound is any one of the following structures:

7. An organic electroluminescent device comprising a cathode, an anode and a functional layer, wherein the functional layer is located between the cathode and the anode, characterized in that at least one functional layer in the organic electroluminescent device contains the compound containing triazine and dibenzopentacyclic structures according to any one of claims 1 to 6. 8 . The organic electroluminescent device according to claim 7 , wherein the functional layer comprises a light-emitting layer, wherein the light-emitting layer contains the compound containing triazine and dibenzopentacyclic structures according to any one of claims 1 to 6 . 9. The organic electroluminescent device according to claim 8, wherein the luminescent host material of the luminescent layer is a mixture of the compound containing triazine and dibenzo pentacyclic structure according to any one of claims 1 to 6 and any one or more of compounds GH-1 to GH-170, wherein the specific structures of the compounds GH-1 to GH-170 are:

10 . A lighting or display element, characterized in that the lighting or display element comprises the organic electroluminescent device according to any one of claims 7 to 9.

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