An organic metal iridium complex and an organic electroluminescent device comprising the same

Abstract

The application belongs to the technical field of organic electroluminescence diode, and discloses an organic metal iridium complex and an organic electroluminescence device containing the same. The structure of the organic metal iridium complex is shown in formula I: the organic metal iridium complex provided by the application increases the fixed position of nitrogen hetero-benzodifuran as a ligand, and substitutes a tertiary butyl on a naphthalene ring on the ligand, so that the structure combination of the main ligand and the auxiliary ligand is adjusted, and the luminous efficiency and the life of the organic electroluminescence device are further improved.

Description

Technical Field

[0001] This invention belongs to the field of organic light-emitting diode technology, specifically relating to an organometallic iridium complex and an organic light-emitting device containing the same. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are a type of device with a sandwich-like structure, consisting of positive and negative electrode layers and an organic functional material layer sandwiched between them. When a voltage is applied to the electrodes of an OLED device, positive charges are injected from the positive electrode and negative charges from the negative electrode. Under the influence of an electric field, the positive and negative charges migrate, meet, and recombine within the organic layer to emit light. Due to their advantages such as high brightness, fast response, wide viewing angle, simple manufacturing process, and flexibility, OLED devices have attracted significant attention in the fields of new display technology and new lighting technology. Currently, this technology is widely used in display panels for new lighting fixtures, smartphones, and tablets, and its application is expected to expand further into large-size display products such as televisions. It is a rapidly developing and technologically demanding new display technology.

[0003] As OLED technology continues to advance in both lighting and display fields, research into its core materials is receiving increasing attention. This is because a high-efficiency, long-lifespan OLED device is typically the result of optimized device structure and the combination of various organic materials. To fabricate OLED devices with lower driving voltages, better luminous efficiency, and longer lifespans, and to continuously improve OLED device performance, innovation in OLED device structure and manufacturing processes is necessary, along with ongoing research and innovation in the optoelectronic functional materials used in OLED devices to develop higher-performance functional materials. Based on this, the OLED materials community has been dedicated to developing new organic electroluminescent materials to achieve devices with low start-up voltages, high luminous efficiency, and superior lifespans. Summary of the Invention

[0004] In view of this, and to address the shortcomings of the prior art, this invention discloses an organometallic iridium complex and an organic electroluminescent device comprising the same. The organometallic iridium complex disclosed in this invention adds a phenyl group as a ligand to a fixed position on the azidobenzofuran, and substitutes a tert-butyl group on the naphthalene ring of the ligand. By adjusting the structural combination of the main ligand and the auxiliary ligand, the luminous efficiency and lifetime of the organic electroluminescent device can be further improved.

[0005] To achieve the above objectives, the first objective of this invention is to provide an organometallic iridium complex, employing the following technical solution:

[0006] An organometallic iridium complex having the structure of formula I:

[0007]

[0008] in,

[0009] R1, R2, R3, and R4 are each independently selected from hydrogen, deuterium, methyl, ethyl, propyl, and tert-butyl.

[0010] R x and R y Each is independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C30 alkyl groups;

[0011] R Z Selected from hydrogen, -CN, -D or -CD3.

[0012] Optionally, R x and R y Each is independently selected from hydrogen, deuterium, substituted or unsubstituted C1-C12 alkyl groups.

[0013] Furthermore, R x and R y Each is independently selected from hydrogen, deuterium, and any of the following structures:

[0014]

[0015] Indicates the location of the substituent connection.

[0016] Furthermore, the above-mentioned groups can be partially or completely replaced by deuterium.

[0017] In the above technical solution, "substitution" means that the hydrogen atom bonded to the carbon atom of the compound becomes another substituent, and there is no restriction on the position of substitution, as long as the position is where the hydrogen atom is substituted (i.e., the position where the substituent can be substituted), and when there are two or more substituents, the two or more substituents can be the same as or different from each other.

[0018] Furthermore, the term "substitution" as used above means substitution by one, two, or more substituents selected from the following: deuterium, cyano, deuterated methyl, C1-C6 alkyl, C3-C10 cycloalkyl, alkoxy, C6-C18 aryl, C3-C24 heterocyclic, or substitution by two or more substituents linked together from the substituents shown above, or no substituents.

[0019] Furthermore, Formula I has any one of the following structures:

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] A second objective of the present invention is to provide an organic electroluminescent device comprising an organic layer; wherein the organic layer contains an organometallic iridium complex as described above.

[0032] Specifically, the organic electroluminescent device includes an anode, a cathode, and an organic layer disposed between the anode and the cathode.

[0033] Furthermore, the organic layer includes a light-emitting layer, which contains the organometallic iridium complex; and the organometallic iridium complex serves as a red light doping material.

[0034] Compared with the prior art, the present invention provides an organometallic iridium complex and an organic electroluminescent device comprising the same, which has the following superior effects:

[0035] The organometallic iridium complex disclosed in this invention adds a phenyl group as a ligand to a fixed position on the aziridine furan, and replaces the tert-butyl group on the naphthalene ring of the ligand. By adjusting the structural combination of the main ligand and the auxiliary ligand, the luminous efficiency and lifetime of organic electroluminescent devices can be further improved. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0037] Figure 1The 1H NMR spectrum of the organometallic iridium complex L-4. Detailed Implementation

[0038] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments and related drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] This invention specifically discloses an organometallic iridium complex and an organic electroluminescent device containing the same.

[0040] The specific embodiments described below are only some embodiments of this application, and not all embodiments.

[0041] The features and performance of the present invention will be further described in detail below with reference to specific embodiments.

[0042] Example 1: Preparation of organometallic iridium complex L-4

[0043] The specific operation and process route are as follows:

[0044]

[0045] Step 1: Under nitrogen protection, weigh raw material A-4 (CAS: 1354021-0902, 485 mmol), raw material B-4 (CAS: 762287-59-2, 509 mmol), anhydrous potassium carbonate (485 mmol), dimethoxyethane (1000 mL), and water (500 mL). Replace the nitrogen twice. Under nitrogen, add tetrakis(triphenylphosphine)palladium (9.7 mmol) to the system and reflux for 24 hours. After the reaction stops, cool the system to room temperature, separate the liquids with ethyl acetate, and recrystallize through a silica gel funnel to obtain intermediate C-4 (73.4 g, yield 60.2%).

[0046] HPLC purity: ≥99%.

[0047]

[0048] Step 2: Under nitrogen protection, tetrahydrofuran (400 mL), glacial acetic acid (1100 mL), and intermediate C-4 (289 mmol) were added sequentially to the reaction system. The temperature was controlled at 0 °C, and tert-butyl nitrite (867 mmol) was slowly added dropwise to the system. The reaction was carried out for 48 hours. After the reaction was stopped, the system was cooled to room temperature, separated by standing with ethyl acetate, evaporated to dryness, passed through a silica gel funnel, and subjected to column chromatography. The developing solvent was petroleum ether and dichloromethane. Evaporation was carried out to dryness to obtain intermediate D-4 (33.4 g, yield 52.3%).

[0049] HPLC purity: ≥99%.

[0050]

[0051] Step 3: Weigh D-4 (149 mmol), E-4 (149 mmol, CAS: 2217657-10-6), potassium acetate (372 mmol), and 1,4-dioxane (561 mL) under nitrogen conditions, and add them sequentially to a three-necked flask. Replace the nitrogen twice. Under nitrogen conditions, add bis(di-benzylacetone)palladium (1.49 mmol) and 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (11.9 mmol). React at 100 °C for 24 h. After the reaction is complete, cool to room temperature, evaporate the system to dryness, and perform column chromatography. Use petroleum ether and ethyl acetate as developing solvents. Evaporate to dryness to obtain intermediate F-4 (34.9 g, yield 63.5%).

[0052] HPLC purity: ≥99%.

[0053]

[0054] Step 4: Weigh F-4 (92 mmol), G-4 (101.2 mmol, CAS: 98-80-6), potassium carbonate (184 mmol), toluene (340 mL), ethanol (170 mL), and water (170 mL) under nitrogen conditions and add them to the reaction system. Replace the nitrogen atmosphere twice. Add tetrakis(triphenylphosphine)palladium (1.84 mmol) under nitrogen conditions and react at 100 °C for 24 h. After the reaction is complete, cool to room temperature, separate the ethyl acetate, evaporate to dryness, and perform column chromatography. Develop with petroleum ether and ethyl acetate, and evaporate to dryness to obtain intermediate H-4 (28.3 g, yield 72.8%).

[0055] HPLC purity: ≥99%.

[0056]

[0057] Step 5: First, weigh intermediate H-4 (65 mmol) and iridium trichloride trihydrate (26 mmol) and add them to the reaction system. Then add ethylene glycol ethyl ether (224 mL) and water (74 mL), replace the nitrogen gas twice, raise the temperature to 120 °C, and react for 48 h. After the reaction is completed, lower the temperature to 30 °C and filter. Wash the filter cake with ethanol and petroleum ether and dry it to obtain bridging ligand I-4 (36.1 g, yield 51.1%).

[0058]

[0059] Step 6: Weigh out bridging ligand I-4 (8.3 mmol), potassium carbonate (166 mmol), and ethylene glycol ethyl ether (432 mL) and add them sequentially to the reaction system. Replace the nitrogen atmosphere twice. Under nitrogen atmosphere, add 3,7-diethyl-3,7-dimethylnonane-4,6-dione (49.8 mmol). Heat to 120 °C and react for 36 h. After the reaction is complete, filter, pass through a silica gel funnel, and evaporate to dryness to obtain organometallic iridium complex L-4 (9.3 g, yield 43.6%).

[0060] Mass spectrometry: Measured value 1284.55

[0061] HPLC purity: ≥99%

[0062] Elemental analysis:

[0063] Calculated values: C 71.99%, H 5.88%, N 2.18%, O 4.98%.

[0064] Measured values: C 71.86%, H 5.84%, N 2.17%, O 4.95%.

[0065] The proton NMR spectrum of L-4 is shown below. Figure 1 .

[0066] Example 2-10

[0067] The following compounds were synthesized according to the preparation method in Example 1. The mass spectrometer was tested using a Waters XEVO TQD, which has low precision, and an ESI source was used for testing. The mass spectrometry test values ​​are shown in Table 1 below.

[0068] Table 1 Mass spectrometry test values ​​of Examples 2-10

[0069] compound Molecular formula Mass spectrometry test values L-8 <![CDATA[C79H 79 IrN2O4]]> 1312.61 L-9 <![CDATA[C 79 H 79 IrN2O4]]> 1312.66 L-12 <![CDATA[C 79 H 79 IrN2O4]]> 1312.75 L-19 <![CDATA[C 76 H 74 IrN2O4]]> 1271.54 L-20 <![CDATA[C 78 H 78 IrN2O4]]> 1299.61 L-29 <![CDATA[C 70 H 62 IrN2O4]]> 1187.51 L-63 <![CDATA[C 76 H 74 IrN2O4]]> 1271.56 L-69 <![CDATA[C 75 H 72 IrN2O4]]> 1257.60 L-130 <![CDATA[C 75 H 72 IrN2O4]]> 1257.56

[0070] In addition, it should be noted that other compounds of the present invention can be obtained by referring to the preparation methods of the examples listed above, so they will not be listed one by one here.

[0071] Device Example 1: Fabrication of Organic Electroluminescent Devices

[0072] Organic electroluminescent devices were fabricated using an organometallic iridium complex of type L-4. The specific process is as follows:

[0073] The coating thickness is The ITO glass substrate was rinsed twice in distilled water, ultrasonically washed for 30 minutes, rinsed twice more in distilled water, and ultrasonically washed for 10 minutes. After the distilled water rinsing, it was ultrasonically washed in sequence with isopropanol, acetone, and methanol (once each time, for 10 minutes each time), dried, and transferred to a plasma cleaner. The substrate was then washed for 5 minutes and sent to a vapor deposition machine. Using ITO as the anode, CuPc was first vapor deposited on it. Next, NPB was deposited sequentially. A mixture of the host substance 4,4'-N,N'-biphenyldicarbazole (“CBP”) and compound L-4 (in a weight ratio of 95:5), and an electron transport layer “Alq3”. Electron-injected LiF cathode Al The organic electroluminescent device L-4 was prepared.

[0074] The structural formulas of the compounds copper(II) phthalocyanine (CuPc), NPB, Alq3, and CBP used in this invention are as follows:

[0075]

[0076] According to the above preparation scheme, replace formula L-4 with the organometallic iridium complexes in Table 2 in turn to prepare the corresponding organic electroluminescent devices.

[0077] Device Comparison:

[0078] The device comparative examples were prepared according to the method provided in Device Example 1 above, except that the L-4 doped in the light-emitting layer of Device Example 1 was replaced with organometallic compound 1, organometallic compound 2, organometallic compound 3, organometallic compound 4, and organometallic compound 5 to prepare devices E, F, G, H, and I respectively. The structural formulas of organometallic compounds 1-5 are as follows:

[0079]

[0080] The luminescence characteristics of the organic electroluminescent devices obtained from the above-described device embodiments and comparative examples were tested. Measurements were performed using a KEITHLEY 2400 source measurement unit and a CS-2000 spectroradiometer to evaluate the driving voltage, current efficiency, and phosphorescence lifetime. The specific test results are shown in Table 2 below.

[0081] Table 2

[0082]

[0083]

[0084] As can be seen from Table 2, at a current density of 10 mA / cm² 2 By comparison, it can be seen that the absence of fluorine in the structure reduces the steric hindrance, making the product easier to dissolve, thereby significantly reducing the driving voltage of the device of the present invention. In the organometallic iridium complex disclosed in the present invention, a phenyl group is added as a ligand at a fixed position on the aziridine furan, and a tert-butyl group is substituted on the naphthalene ring on the ligand. By adjusting the structural combination of the main ligand and the auxiliary ligand, the current efficiency and lifetime of the organic electroluminescent device can be further improved.

[0085] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organometallic iridium complex, characterized in that, The general structural formula of the organometallic iridium complex is shown in Formula I: ； in, R1, R2, R3, and R4 are each independently selected from hydrogen, deuterium, methyl, ethyl, propyl, and tert-butyl. R x and R y Each is independently selected from hydrogen, deuterium, and any of the following structures: ； " "Indicates the location of the substituent connection; R Z Selected from hydrogen, -CN, -D or -CD3.

2. An organometallic iridium complex, characterized in that, The structure of the organometallic iridium complex is selected from any one of the following compounds: ； ； 。 3. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes an organic layer; the organic layer contains an organometallic iridium complex as described in any one of claims 1-2.

4. The organic electroluminescent device according to claim 3, characterized in that, The organic layer includes a light-emitting layer, and the light-emitting layer contains the organometallic iridium complex.

5. The organic electroluminescent device according to claim 4, characterized in that, The organometallic iridium complex serves as a red light doping material.

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