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

Abstract

The present invention relates to a compound containing a triazine and a dibenzo five-membered ring structure and its application, belonging to the field of semiconductor technology. The structure of the compound provided by the present invention is shown in the general formula (1): After the compound of the present invention is applied to the light-emitting layer or the electron transport layer of an OLED device, it can effectively reduce the voltage of the device, improve the current efficiency and service life of the device.

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 an electron transport region may exist 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 the 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 are usually problems of hole and electron imbalance in the light-emitting layer and serious efficiency roll-off of the device at high current density. 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 present invention provides a compound containing a triazine and a dibenzo five-membered ring structure and its applications. The present invention provides a host alternative material with low voltage and low turn-on voltage, high efficiency, especially longer 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 as general formula (1):

[0008]

[0009] In general formula (1), X represents an oxygen or sulfur atom; Y each occurrence independently represents C-H or C-D;

[0010] A1 represents a structure shown in any one of general formulas (2-1) to (2-3):

[0011]

[0012] In General Formulas (2-1) to (2-3), X0 represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D. In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (3-1) to (3-3):

[0013]

[0014] The meanings of X, X0, and Y are as defined above.

[0015] In a preferred embodiment, the structure of the compound is represented by any one of General Formulas (4-1) to (4-8):

[0016]

[0017] The meanings of X, X0, and Y are as defined above.

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

[0019]

[0020] In General Formulas (1-1) to (1-4), X represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D; A1 represents a structure represented by any one of General Formulas (2-1) to (2-3):

[0021]

[0022] In General Formulas (2-1) to (2-3), X0 represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D. In a preferred embodiment, A1 represents a structure represented by any one of General Formulas (a-1) to (a-11):

[0023]

[0024]

[0025] In General Formulas (a-1) to (a-11), X0 represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D. In a preferred embodiment, the specific structure of the compound containing a triazine and a dibenzo five-membered ring structure is any one of the following compounds:

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039] An organic electroluminescent device, comprising a cathode, an anode and a functional layer, the functional layer being located between the cathode and the anode, and at least one functional layer containing the compound having a triazine and a dibenzo five-membered ring structure.

[0040] Preferably, the functional layer includes a light-emitting layer, and the light-emitting layer contains the compound having a triazine and a dibenzo five-membered ring structure.

[0041] More preferably, the light-emitting host material of the light-emitting layer is formed by mixing the compound having a triazine and a dibenzo five-membered ring structure with any one or more of compounds GH-1 to GH-170, and the specific structures of the compounds GH-1 to GH-170 are:

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048]

[0049]

[0050] More 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 pentacyclic ring structure.

[0051] An illumination or display element, characterized in that the illumination or display element includes the organic electroluminescent device described above.

[0052] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0053] 1) The bridging mode between the carbazole group and the dibenzo pentacyclic ring in the compound provided by the present invention makes it have a longer normal temperature life and high temperature life compared with the compounds in the prior art, and at the same time has a higher luminous efficiency, which helps to improve the overall performance of the device.

[0054] 2) 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 under high current density and improve the device life. Brief Description of the Drawings

[0055] Figure 1 It is a schematic structural diagram of the materials listed in the present invention applied to an OLED device;

[0056] 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. Detailed Embodiments

[0057] The raw materials involved in the synthesis examples of the present invention can be purchased from the market.

[0058] The principles and features of the present invention will be described below in conjunction with the drawings and embodiments. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention.

[0059] 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 expressed in 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 larger the absolute value of the energy level, the lower the energy of the energy level.

[0060] Any numerical range recited herein is intended to include all sub-ranges having the same numerical precision that fall within the recited range. For example, "1.0 to 10.0" is intended to include all sub-ranges between the recited minimum value of 1.0 and the recited 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 limitation recited herein is intended to include all smaller numerical limitations incorporated herein, and any minimum numerical limitation recited herein is intended to include all larger numerical limitations incorporated herein. Accordingly, the applicant reserves the right to amend this specification, including the claims, to expressly describe any sub-ranges that fall within the ranges expressly described herein.

[0061] In the drawings, for the sake of 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 can be directly on the other layer or substrate, or an intermediate layer may be present. Additionally, it will be understood that when a layer is referred to as being "between" two layers, the layer can be the only layer between the two layers, or one or more intermediate layers may be present. The same reference numerals throughout the specification denote the same elements.

[0062] In the present invention, when describing electrodes, organic electroluminescent devices, and other structures, terms indicating orientation such as "upper", "lower", "top", and "bottom" only represent the orientation in a specific state, and do not mean that the relevant structures can only exist in the stated orientation; on the contrary, if the structure can be transformed in position, for example, inverted, the orientation of the structure will be changed accordingly. Specifically, in the present invention, the "bottom" and "lower" sides of the electrode refer to the side of the electrode that is close to the substrate during the preparation process, and the opposite side away from the substrate is the "top" and "upper" sides.

[0063] Synthesis of Intermediate

[0064]

[0065] Synthesis of Intermediate C-1: Add 5 mmol of Intermediate A-1, 5 mmol of Intermediate B-1, 50 mL of toluene, 16 mL of ethanol, 15 mmol of aqueous potassium carbonate solution, and 0.2 mmol of Pd(PPh3)4 to a three-necked flask. Protect with nitrogen and react at reflux temperature for 8 h. After the reaction is completed, cool to room temperature, quench the reaction with water, extract three times with ethyl acetate, combine the organic phases, then dry with anhydrous sodium sulfate, filter and concentrate to obtain the crude product. Purify by recrystallization (ethyl acetate / petroleum ether) to obtain Intermediate C-1.

[0066] Synthesis of Intermediate E-1: Add 3 mmol of Intermediate C-1, 4 mmol of Intermediate D-1, 9 mmol of KOAc, 0.3 mmol of S-phos, and 0.6 mmol of Pd2(dba)3 to 80 mL of dioxane in a three-necked flask. Under nitrogen protection, reflux the reaction for 8 h. Cool the reaction system to room temperature, dilute the reaction solution with ethyl acetate, wash it with saturated brine, dry it over anhydrous sodium sulfate, distill it under reduced pressure, and purify it by silica gel column chromatography using petroleum ether / ethyl acetate (9:1) as the eluent to obtain Intermediate E-1.

[0067]

[0068] Synthesis of Intermediate C-2: Add Intermediate A-4 (20 mmol), Intermediate B-3 (20 mmol), Pd2(dba)3 (0.5 mmol), S-Phos (1.0 mmol), K2CO3 (200 mmol), and toluene (100 mL) to the flask in sequence. Then replace the nitrogen and protect it, and stir overnight at 110 °C. After the reaction is completed, cool it to room temperature, add ethyl acetate to dilute the reaction solution, quench it with water, extract the aqueous phase with ethyl acetate three times, combine the organic phases, wash them with saturated brine, dry them over anhydrous sodium sulfate, concentrate the organic phase, and purify it by silica gel column chromatography to obtain Intermediate C-2.

[0069] Synthesis of Intermediate E-4: Add 3 mmol of Intermediate C-2, 6 mmol of Intermediate D-1, 9 mmol of KOAc, 0.4 mmol of S-phos, and 0.2 mmol of Pd2(dba)3 to 100 mL of dioxane in a three-necked flask. Under nitrogen protection, reflux the reaction for 8 h. Cool the reaction system to room temperature, dilute the reaction solution with ethyl acetate, wash it with saturated brine, dry it over anhydrous sodium sulfate, distill it under reduced pressure, and purify it by silica gel column chromatography using petroleum ether / ethyl acetate (9:1) as the eluent to obtain Intermediate E-4.

[0070] Synthesize the following target compounds with reference to the preparation processes of Intermediate E-1 or E-4; the reaction conditions are the same, except that Intermediate A and Intermediate B listed in Table 1 below are used;

[0071] Table 2

[0072]

[0073]

[0074] Example 1: Synthesis of Compound 6:

[0075]

[0076] Add intermediate F-1 (1.0 mmol) into a flask, and successively add intermediate E-1 (1.1 mmol), saturated aqueous solution of K2CO3 (3.0 mmol), toluene (25 mL), 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, and purify the obtained residue by silica gel column chromatography to obtain compound 6;

[0077] Synthesize the following target compounds with reference to the preparation process of Example 1; the reaction conditions are the same, except that the intermediate F and intermediate E listed in Table 1 below are used;

[0078] Table 2

[0079]

[0080]

[0081]

[0082]

[0083] The compounds of the present invention can be used in light-emitting devices and can be used as light-emitting layer materials. The physical, chemical and optoelectronic properties of the compounds prepared in the above examples of the present invention were tested respectively, and the test results are shown in Table 2:

[0084] Table 2

[0085]

[0086]

[0087] Note: The triplet energy level T1 was tested by a Horiba Fluorolog-3 series fluorescence spectrometer, and the material test sample was a toluene solution of 2*10 -5 mol / L; the glass transition temperature Tg was determined by differential scanning calorimetry (DSC, Netzsch DSC204F1 differential scanning calorimeter), with a heating rate of 10 °C / min; the highest occupied molecular orbital HOMO energy level was tested by an ionization energy test system (IPS-3), and the test was carried out in an atmospheric environment; Eg was tested by a double-beam ultraviolet-visible spectrophotometer (model: TU-1901), and LUMO = HOMO + Eg. The electron mobility test was carried out by fabricating a single-charge device with the material of the present invention and measuring it by the SCLC method.

[0088] As can be seen from the data in the above table, the organic compound of the present invention has a high glass transition temperature (Tg), which can improve the phase stability and high-temperature stability of the material film; the organic compound of the present invention has appropriate HOMO and LUMO energy levels, which can reduce the injection barrier of carriers, lower the device voltage and improve the device efficiency. The organic compound of the present invention has a relatively high T1 energy level, and when used as a host material, it can ensure the energy transfer efficiency between the host and the guest and suppress energy loss.

[0089] The organic compound of the present invention is characterized by high electron mobility, which is beneficial to reducing the device voltage and improving the current efficiency.

[0090] The application effect of the synthesized OLED material of the present invention in the device is described in detail below through Device Examples 1-38 and Device Comparative Examples 1-8. Compared with Device Comparative Examples 1-8, the manufacturing processes of the devices in Device Examples 1-38 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.

[0091] Device Example 20

[0092] As Figure 1As 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, sequentially 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 is completed, the light-emitting layer 6 of the OLED light-emitting device is fabricated. Its structure includes compound 6 and GH-2 used in the OLED light-emitting layer 6 as the host materials, and GD-1 as the guest material. The mass ratio of compound 6, 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 vacuum-evaporated with a mass ratio of ET-1 and Liq of 1:1 and 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. 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 70 nm. The organic electroluminescent device 20 is obtained.

[0093] The molecular structural formulas of the related materials are as follows:

[0094]

[0095]

[0096] 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, 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 Table 4.

[0097] Table 3

[0098]

[0099]

[0100] Table 4

[0101]

[0102] 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 Research Co., Ltd. of Japan; the device lifetime LT95 refers to the time when the device brightness decays to 95% of the initial brightness at a current density of 20 mA / cm 2 ; the high-temperature device lifetime LT95 refers to the time when the device brightness decays to 95% of the initial brightness 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 brightness is 1 nit.

[0103] It can be seen from the device data results in Table 4 that compared with the device comparative example, the organic light-emitting device of the present invention has been improved in terms of device voltage, device efficiency, and device lifetime compared with the OLED device of known materials. In particular, the turn-on voltage and high-temperature lifetime of the device have been significantly improved.

[0104] 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 1-38 and Comparative Examples 1-8 of the device

[0105] The results are shown in Table 5:

[0106]

[0107] It can be seen from the data in Table 5 that 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 densities.

[0108] 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 replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in 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 shown in general formula (1): In general formula (1), X represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D; The said A1 represents any one of general formulas (a-1) to (a-11): In general formulas (a-1) to (a-11), X0 represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D, and the Y at the connecting site represents a C atom.

2. The compound containing a triazine and a dibenzo five-membered ring structure according to claim 1, characterized in that, The structure of the said compound is shown as any one of general formulas (1-1) to (1-4): In general formulas (1-1) to (1-4), X represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D; The said A1 represents any one of general formulas (a-1) to (a-11): In general formulas (a-1) to (a-11), X0 represents an oxygen or sulfur atom; each occurrence of Y independently represents C-H or C-D, and the Y at the connecting site represents a C atom.

3. A compound containing a triazine and a dibenzo five-membered ring structure, characterized in that, The specific structure of the said compound is any one of the following compounds:

4. 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 contains the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 3.

5. The organic electroluminescent device according to claim 4, wherein the functional layer includes a light-emitting layer, characterized in that, The said light-emitting layer contains the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 3.

6. The organic electroluminescent device according to claim 5, characterized in that, The said light-emitting layer comprises a host material and a doping material, and the host material contains the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 3.

7. The organic electroluminescent device according to claim 6, characterized in that, The light-emitting host material of the said light-emitting layer is formed by mixing the compound containing a triazine and a dibenzo five-membered ring structure according to any one of claims 1 to 3 with any one or more of compounds GH-1 to GH-170, and the specific structures of the compounds GH-1 to GH-170 are:

8. An illumination or display element, characterized in that, The said lighting or display element includes the organic electroluminescent device according to any one of claims 4 to 7.

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