A compound containing a triazine and a dibenzo five-membered ring structure and its application

Abstract

The present invention discloses a compound containing a triazine and a dibenzo five-membered ring structure. The structure of the compound is shown as general formula (1): In general formula (1), R₁ and R₂ each independently represent phenyl, deuterated phenyl, hydrogen or deuterium; X represents an oxygen or sulfur atom; A represents a structure shown as general formula (2). In general formula (2), Z₀, Z₁, Z₂, Z₃, Z₄, Z₅, Z₆ each occurrence independently represents C-H or C-D. The compound of the present invention is used in an organic electroluminescent device, has the characteristics of low voltage, low turn-on voltage and high efficiency, and can be used as a host substitute material for longer device life and longer high-temperature life.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and more particularly to a compound containing a triazine and a dibenzo five-membered ring structure and its applications. Background Art

[0002] There may be a hole transport region between the anode and the light-emitting layer of an organic electroluminescent device, and there may be an electron transport region between the light-emitting layer and the cathode. Holes from the anode can migrate to the light-emitting layer through the hole transport region, and electrons from the cathode can migrate to the light-emitting layer through the electron transport region. The holes and electrons recombine in the light-emitting layer to generate excitons. According to the spin-coupling effect of heavy metal atoms, an organometallic compound material can directly emit energy from the triplet state to the ground state, and theoretically, a 100% internal quantum yield can be achieved.

[0003] However, for phosphorescent OLEDs that emit light from the triplet state, there is still a need for improvement in terms of device voltage, current efficiency, and lifetime. The performance of the host material in the light-emitting layer usually affects the above key performance of the organic electroluminescent device to a large extent. According to the prior art, the compounds used as host materials usually contain triazine groups. However, when existing triazine derivatives are used as host materials, there is a need for improvement in device voltage, current efficiency, especially in the turn-on voltage and device lifetime. The present invention provides a host alternative material with low voltage, high efficiency, long lifetime, especially low turn-on voltage and long high-temperature lifetime.

[0004] For phosphorescent OLEDs, there is usually an imbalance between holes and electrons in the light-emitting layer, and the device efficiency roll-off is serious at high current densities. The present invention also provides a combination of two host materials, which can effectively solve the above deficiencies. Summary of the Invention

[0005] In view of the above problems existing in the prior art, the applicant of the present invention provides a compound containing a triazine and a dibenzo five-membered ring structure and its applications. The compound of the present invention is used in an organic electroluminescent device, and has the characteristics of low voltage, low turn-on voltage, and high efficiency, and can be used as a host alternative material with longer device lifetime and longer high-temperature lifetime.

[0006] The technical solution of the present invention is as follows:

[0007] A compound containing a triazine and a dibenzo five-membered ring structure, the structure of the compound is shown in general formula (1):

[0008]

[0009] In general formula (1), R1 and R2 each independently represent a phenyl group, a deuterated phenyl group, hydrogen or deuterium;

[0010] X represents an oxygen or sulfur atom;

[0011] A is represented by the structure shown in General Formula (2):

[0012]

[0013] A is connected to Z3, Z4, Z5 or Z6 by a single bond;

[0014] Each occurrence of Z0, Z1, Z2, Z3, Z4, Z5, Z6 is independently represented as C-H or C-D.

[0015] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (3-1) to (3-4):

[0016]

[0017] The meanings of A, X, R1, R2, Z1, Z2, Z3, Z4, Z5, Z6 are as defined above.

[0018] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (4-1) to (4-4):

[0019]

[0020] The meanings of A, X, Z1, Z2, Z3, Z4, Z5, Z6 are as defined above.

[0021] In a preferred embodiment, at least one aromatic ring in the structure of the compound represented by General Formulas (4-1) to (4-2) is an aromatic ring substituted with deuterium, and the aromatic ring is a benzene ring, a carbazole ring or dibenzofuran.

[0022] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (5-1) to (5-2):

[0023]

[0024] The meanings of A, X, R1, R2, Z1, Z2, Z3, Z4, Z5, Z6 are as defined above.

[0025] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (5-3) to (5-4):

[0026]

[0027] The meanings of A, X, R1, R2, Z1, Z2, Z3, Z4, Z5, Z6 are as defined above.

[0028] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (6-1) to (6-6):

[0029]

[0030]

[0031] In General Formulas (6-1) to (6-6), R1 and R2 each independently represent phenyl, deuterated phenyl, hydrogen, or deuterium; X represents an oxygen or sulfur atom; A represents the structure shown in General Formula (2):

[0032]

[0033] A is connected to Z3, Z4, Z5, or Z6 by a single bond; each occurrence of Z0, Z1, Z2, Z3, Z4, Z5, Z6 independently represents C-H or C-D.

[0034] In a preferred embodiment, the specific structure of the compound is any one of the following structures:

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] An organic electroluminescent device includes a cathode, an anode, and a functional layer, the functional layer is located between the cathode and the anode, and at least one of the functional layers in the organic electroluminescent device contains the compound containing a triazine and a dibenzo five-membered ring structure.

[0042] Preferably, the functional layer includes a light-emitting layer, and the light-emitting layer contains the compound containing a triazine and a dibenzo five-membered ring structure.

[0043] More preferably, the light-emitting host material of the light-emitting layer is composed of the compound containing a triazine and a dibenzo five-membered ring structure and any one or more of Compounds GH-1 to GH-170, and the specific structures of Compounds GH-1 to GH-170 are:

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] Preferably, the functional layer includes a hole blocking layer and / or an electron transport layer, and the hole blocking layer and / or the electron transport layer contains the compound containing a triazine and a dibenzo five-membered ring structure.

[0054] An illumination or display element, and the illumination or display element includes the organic electroluminescent device.

[0055] The beneficial technical effects of the present invention are as follows:

[0056] The bridging mode between the carbazole group and the dibenzo five-membered ring in the compound provided by the present invention makes it have a higher carrier mobility compared with the compounds in the prior art, which helps to improve the overall performance of the device.

[0057] The compound provided by the present invention further introduces deuterium atoms in the side chain, and applying it to the light-emitting layer helps to improve the efficiency roll-off problem of the device under high current density and improve the device life. Brief Description of the Drawings

[0058] Figure 1 It is a schematic structural diagram of the materials listed in the present invention applied to an OLED device;

[0059] 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;

[0060] Figure 2 It is the 1H NMR spectrum of Compound 56. Detailed Embodiments

[0061] The present invention will be specifically described below in conjunction with the drawings and embodiments.

[0062] In the present invention, unless otherwise specified, HOMO means the highest occupied molecular orbital, and LUMO means the lowest unoccupied molecular orbital. In addition, in the present invention, the HOMO and LUMO energy levels are represented by absolute values, and the comparison between energy levels is also a comparison of the magnitudes of their absolute values. Those skilled in the art know that the greater the absolute value of the energy level, the lower the energy of that energy level.

[0063] Any numerical range listed herein is intended to include all sub-ranges having the same numerical precision within the listed range. For example, "1.0 to 10.0" means including all sub-ranges between the listed minimum value of 1.0 and the listed maximum value of 10.0 (and including 1.0 and 10.0), that is, all sub-ranges having 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 incorporated herein, and any minimum numerical limit listed herein is intended to include all larger numerical limits incorporated herein. Therefore, the applicant reserves the right to modify this specification, including the claims, to clearly describe any sub-range that falls within the range clearly described herein.

[0064] In the drawings, for clarity, the dimensions of layers and regions may be exaggerated. 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 an intermediate layer. In addition, it will also 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 intermediate layers. The same reference numerals throughout the text denote the same elements.

[0065] In the present invention, when describing electrodes, organic light-emitting devices, and other structures, the terms indicating orientation such as "upper", "lower", "top", and "bottom" only represent the orientation in a certain specific state, and do not mean that the relevant structure can only exist in the described orientation; on the contrary, if the structure can be transformed in position, for example, inverted, the orientation of the structure is changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of the electrode refer 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" and "upper" sides.

[0066] Example 1: Synthesis of Compound 2:

[0067]

[0068] Add intermediate A-1 (1.0 mmol) to a flask, and then successively add intermediate B-1 (1.1 mmol), saturated K2CO3 solution (3.0 mmol), THF (25 mL), and Pd(PPh3)4 (0.1 mmol); reflux for two days under nitrogen protection. After the reaction is completed, cool to room temperature, extract with dichloromethane (150 mL × 3), then add anhydrous sodium sulfate for drying, filter and concentrate the organic phase. The obtained residue is purified by silica gel column chromatography to obtain compound 2; LC-MS: theoretical value: 716.26; measured value ([M+H]+): 717.42.

[0069] The synthesis of intermediate A-1 is as follows:

[0070]

[0071] Add raw material a-1 (10.0 mmol), raw material b-1 (25.0 mmol), Pd(PPh3)4 (1.0 mmol), aqueous solution of saturated K2CO3 (50.0 mmol), THF (60 mL) to a flask successively, reflux overnight under nitrogen protection. After the reaction is completed, add saturated brine, extract with dichloromethane, dry the organic phase with anhydrous sodium sulfate, and concentrate the obtained residue is purified by silica gel column chromatography to obtain intermediate c-1; LC-MS: theoretical value: 443.10; measured value ([M+H]+): 444.15.

[0072] Add intermediate c-1 (6.0 mmol), Pd(dba)2 (0.3 mmol), S-Phos (0.6 mmol), AcONa (15.0 mmol), toluene (100 mL) to a flask successively, and finally add bis(pinacolato)diboron (10 mmol), reflux overnight under nitrogen protection. After the reaction is completed and cooled to room temperature, dilute the reaction solution with ethyl acetate, then wash with saturated brine, dry the organic phase with anhydrous sodium sulfate, and concentrate the obtained crude product is obtained by trituration (EA / PE = 8:1) to obtain intermediate - A1; LC-MS: theoretical value: 525.22; measured value ([M+H]+): 526.37.

[0073] The synthesis of intermediate A-5 is as follows:

[0074]

[0075] To the flask, add raw material - 1 (10.0 mmol), raw material - 2 (25.0 mmol), Pd(PPh3)4 (1.0 mmol), aqueous solution of saturated K2CO3 (50.0 mmol), THF (60 mL) in sequence. Reflux overnight under nitrogen protection. After the reaction is completed, add saturated brine, extract with dichloromethane, dry the organic phase with anhydrous sodium sulfate, and purify the concentrated residue by silica gel column chromatography to obtain intermediate - 1; LC - MS: theoretical value: 443.16; measured value ([M + H]+): 444.32.

[0076] To the flask, add intermediate - 1 (6.0 mmol), Pd(dba)2 (0.3 mmol), S - Phos (0.6 mmol), AcONa (15.0 mmol), toluene (100 mL) in sequence. Finally, add raw material 3 (10 mmol). Reflux overnight under nitrogen protection. After the reaction is completed and cooled to room temperature, dilute the reaction solution with ethyl acetate, then wash with saturated brine, dry the organic phase with anhydrous sodium sulfate, and obtain intermediate - A5 by trituration (EA / PE = 8:1) of the concentrated crude product; LC - MS: theoretical value: 521.27; measured value ([M + H]+): 522.35.

[0077] The preparation methods of intermediate A - 2, intermediate A - 3, intermediate A - 4, and intermediate A - 6 are the same as those of intermediate A - 1 or intermediate A - 5 above, or can also be prepared by conventional synthesis methods referring to the methods described in the prior art.

[0078] Refer to the preparation process of Example 1 to synthesize the following target compounds; the reaction conditions are the same, except that intermediate B and intermediate A listed in Table 1 below are used.

[0079] Table 1

[0080]

[0081]

[0082]

[0083] The NMR data of compound 56 are as follows: 11H NMR (400 MHz, Chloroform-d) δ 8.93 (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).

[0084] The application effects of the synthesized OLED materials of the present invention in devices are described in detail below through Device Examples 1 - 21 and Device Comparative Examples 1 - 8. Compared with Device Comparative Examples 1 - 8, the manufacturing processes of the devices in Device Examples 1 - 21 of the present invention are exactly the same, and the same substrate materials and electrode materials are used, and the film thicknesses of the electrode materials are also kept consistent. The difference is that the light-emitting layer in the device is replaced.

[0085] Device Example 1

[0086] As Figure 1 shown, the transparent substrate layer 1 is a transparent PI film. The anode layer 2 (ITO (15 nm) / Ag (150 nm) / ITO (15 nm)) is washed, that is, washed with a cleaning agent (SemiClean M-L20), washed with pure water, dried, and then washed with ultraviolet-ozone to remove organic residues on the surface of the anode layer. On the anode layer 2 after the above washing, using a vacuum evaporation device, HT-1 and P-1 are evaporated as the hole injection layer 3 with a film thickness of 10 nm, and the mass ratio of HT-1 and P-1 is 97:3. Then HT-1 is evaporated as the hole transport layer 4 with a thickness of 130 nm. Subsequently, EB-1 is evaporated as the electron blocking layer 5 with a thickness of 40 nm. After the evaporation of the above electron blocking layer material, the light-emitting layer 6 of the OLED light-emitting device is fabricated. Its structure includes compound 2 used as the host material and GD-1 used as the guest material in the OLED light-emitting layer 6, and the mass ratio of compound 2 and GD-1 is 94:6, and the film thickness of the light-emitting layer is 40 nm. After the above light-emitting layer 6, ET-1 and Liq are continuously evaporated in vacuum, and the mass ratio of ET-1 and Liq is 1:1 with a film thickness of 35 nm. This layer is the electron transport layer 7. On the electron transport layer 7, a LiF layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device. This layer is the electron injection layer 8. On the electron injection layer 8, a Mg:Ag electrode layer with a film thickness of 15 nm is fabricated through 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 evaporated in vacuum as the CPL layer 10 with a thickness of 70 nm. The organic electroluminescent device 1 is obtained.

[0087] Device Example 11

[0088] As shown Figure 1 in the figure, the transparent substrate layer 1 is a transparent PI film. The anode layer 2 (ITO (15 nm) / Ag (150 nm) / ITO (15 nm)) is washed, that is, washed with a cleaning agent (SemiClean M-L20), washed with pure water, dried, and then washed with ultraviolet-ozone 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 as the hole injection layer 3 by using a vacuum evaporation device, with a film thickness of 10 nm, and the mass ratio of HT-1 and P-1 is 97:3. Then HT-1 is evaporated as the hole transport layer 4, with a thickness of 130 nm. Subsequently, EB-1 is evaporated as the electron blocking layer 5, with a thickness of 40 nm. After the evaporation of the above electron blocking layer material is completed, the light-emitting layer 6 of the OLED light-emitting device is fabricated. Its structure includes Compound 2 and GH-2 as the host materials and GD-1 as the guest material used in the OLED light-emitting layer 6. The mass ratio of Compound 2, GH-2, and GD-1 is 47:47:6, and the film thickness of the light-emitting layer is 40 nm. After the above light-emitting layer 6, ET-1 and Liq are continuously evaporated in a vacuum, and the mass ratio of ET-1 and Liq is 1:1, with a film thickness of 35 nm. This layer is the electron transport layer 7. On the electron transport layer 7, a LiF layer with a film thickness of 1 nm is fabricated by using a vacuum evaporation device. This layer is the electron injection layer 8. On the electron injection layer 8, a Mg:Ag electrode layer with a film thickness of 15 nm is fabricated by using a vacuum evaporation device. 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 evaporated as the CPL layer 10, with a thickness of 70 nm. The organic electroluminescent device 1 is obtained.

[0089] The molecular structural formulas of the related materials are as follows:

[0090]

[0091] After the OLED light-emitting device is completed as described above, the anode and cathode are connected by a known driving circuit, and the voltage, current efficiency, emission spectrum, and device lifetime 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 lifetime at 20 mA / cm 2 are shown in Tables 4-1 and 4-2.

[0092] Table 3

[0093]

[0094]

[0095] Table 4-1

[0096]

[0097]

[0098] Table 4-2

[0099]

[0100] Note: The voltage, current efficiency, and color coordinates were measured under the condition of a current density of 10 mA / cm 2 using an IVL (current-voltage-luminance) test system (Suzhou FushiDa Scientific Instruments Co., Ltd.); the lifetime test system is the EAS-62C type OLED device lifetime tester of System Technology Co., Ltd. of Japan; the device lifetime LT95 refers to the time taken for the device luminance to decay to 95% of the initial luminance at a current density of 20 mA / cm 2 ; the high-temperature device lifetime LT95 refers to the time taken for the device luminance to decay to 95% of the initial luminance at a current density of 20 mA / cm 2 and a temperature of 85 °C; the turn-on voltage refers to the driving voltage of the device when the device luminance is 1 nit.

[0101] From the device data results in Tables 4-1 and 4-2, it can be seen that compared with the device comparative examples, the organic light-emitting device of the present invention has improved in terms of device voltage, device efficiency, and device lifetime compared to the OLED devices of known materials, especially the turn-on voltage and high-temperature lifetime of the device have been significantly improved.

[0102] To compare the efficiency decay of different devices at high current densities, the efficiency decay coefficient of each device was defined where μ m represents the maximum current efficiency of the device, and μ 50 represents the current efficiency of the device when the driving current is 50 mA / cm 2 . The larger the [[value]], the more serious the efficiency roll-off of the device; on the contrary, it indicates that the problem of rapid decay of the device at high current densities has been controlled. The present invention measured the efficiency decay coefficients of the devices of Examples 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 21 and Comparative Examples 1-8 of the devices and the results are shown in Table 5:

[0103] Table 5

[0104] Device embodiment Efficiency decay coefficient φ Device embodiment Efficiency decay 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 Example 11 0.158 Example 5 0.242 Example 12 0.177 Example 6 0.250 Example 13 0.172 Example 7 0.253 Example 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

[0105] As can be seen from the data in Table 5, the organic light-emitting device prepared with the compound of the present invention has a smaller efficiency decay coefficient compared with the comparative example, indicating that the organic electroluminescent device prepared with the compound of the present invention can effectively reduce the efficiency roll-off of the device at high current density.

[0106] In summary, the above are only the 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 principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A compound containing a triazine and a dibenzo five-membered ring structure, characterized in that, The structure of the said compound is as shown in general formula (1): In general formula (1), R1 and R2 each independently represent phenyl, deuterated phenyl, hydrogen or deuterium; X represents an oxygen or sulfur atom; A represents the structure shown in general formula (2): A is connected to Z3, Z4, Z5 or Z6 by a single bond; Each occurrence of Z0, Z1, Z2, Z3, Z4, Z5, Z6 independently represents C-H or C-D.

2. The compound according to claim 1, wherein The structure of the said compound is represented by any one of general formulas (3-1) to (3-4): The meanings of A, X, R1, R2, Z1, Z2, Z3, Z4, Z5, Z6 are the same as those defined in claim 1.

3. The compound according to claim 2, wherein The structure of the said compound is represented by any one of general formulas (4-1) to (4-4): The meanings of A, X, Z1, Z2, Z3, Z4, Z5, Z6 are the same as those defined in claim 1.

4. The compound according to claim 3, wherein, In the compound structures of general formulas (4-1) to (4-2), at least one aromatic ring is an aromatic ring substituted by deuterium, and the aromatic ring is a benzene ring, a carbazole ring or dibenzofuran.

5. The compound according to claim 1, characterized in that, The structure of the said compound is represented by any one of general formulas (5-1) to (5-2): The meanings of A, X, R1, R2, Z1, Z2, Z3, Z4, Z5, Z6 are the same as those defined in claim 1.

6. The compound according to claim 1, wherein The specific structure of the said compound is any one of the following structures:

7. An organic electroluminescent device comprising a cathode, an anode, and a functional layer, the functional layer being located between the cathode and the anode, characterized in that, At least one functional layer in the said organic electroluminescent device contains the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, wherein the functional layer includes a light-emitting layer, characterized in that, The light-emitting layer contains the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 6.

9. According to the organic electroluminescent device of claim 8, the light-emitting host material of the light-emitting layer is composed of the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 6 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:

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

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