Organic metal iridium complex and organic electroluminescent device containing same

Abstract

The invention belongs to the technical field of organic light-emitting diodes, and discloses an organic metal iridium complex and an organic light-emitting device containing the organic metal iridium complex. The structure of the organic metal iridium complex is shown as a formula I: # imgabs0. In the organic metal iridium complex provided by the invention, phenyl is added at a fixed position on aza-dibenzofuran to serve as a ligand, and a naphthalene ring on the ligand is substituted with tertiary butyl, so that the structural combination of a main ligand and an auxiliary ligand is adjusted; and the luminous efficiency and the service life of the organic electroluminescent device can be further improved.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescent diodes, and in particular relates to an organic metal iridium complex and an organic electroluminescent device containing the same. Background Art

[0002] Organic light emitting diodes (OLED) are a type of device with a sandwich-like structure, including positive and negative electrode film layers and organic functional material layers sandwiched between the electrode film layers. When voltage is applied to the electrodes of the OLED device, positive charges are injected from the positive electrode and negative charges are injected from the negative electrode. Under the action of the electric field, the positive and negative charges migrate in the organic layer and meet to combine and emit light. Due to the advantages of high brightness, fast response, wide viewing angle, simple process, and flexibility, OLED devices have attracted much attention in the fields of new display technology and new lighting technology. At present, this technology has been widely used in display panels of new lighting fixtures, smart phones, tablet computers and other products, and will further expand to the application fields of large-size display products such as televisions. It is a new display technology with fast development and high technical requirements.

[0003] As OLED continues to advance in the two major fields of lighting and display, people are paying more attention to the research of its core materials, because an OLED device with good efficiency and long life is usually the result of an optimized combination of device structure and various organic materials. In order to prepare OLED light-emitting devices with lower driving voltage, better luminous efficiency and longer device life, and to continuously improve the performance of OLED devices, it is necessary not only to innovate the structure and manufacturing process of OLED devices, but also to continuously study and innovate the optoelectronic functional materials in OLED devices to prepare functional materials with higher performance. Based on this, the OLED material community has been committed to developing new organic electroluminescent materials to achieve low device starting voltage, high luminous efficiency and better service life. Summary of the invention

[0004] In view of this, the present invention discloses an organic metal iridium complex and an organic electroluminescent device containing the same in order to address the deficiencies of the prior art. In the organic metal iridium complex disclosed by the present invention, a phenyl group is added as a ligand at a fixed position on the azadibenzofuran, and a tert-butyl group is substituted on the naphthalene ring on the ligand, and the structural combination of the main ligand and the auxiliary ligand is adjusted, so that the luminous efficiency and life of the organic electroluminescent device can be further improved.

[0005] In order to achieve the above object, the first object of the present invention is to provide an organic metal iridium complex, using the following technical solution:

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

[0007]

[0008] in,

[0009] R 1 , R 2 , R 3 , R 4 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;

[0011] R Z Selected from hydrogen, -CN, -D or -CD 3 .

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

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

[0014]

[0015] Indicates the position where a substituent is attached.

[0016] Furthermore, the above groups may be partially or fully substituted by deuterium.

[0017] In the above technical scheme, "substitution" means that the hydrogen atom bonded to the carbon atom of the compound is changed into another substituent, and the position of substitution is not limited, as long as the position is the position where the hydrogen atom is substituted (that is, the position where the substituent can be substituted), and when there are two or more substituents, the two or more substituents may be the same or different from each other.

[0018] Furthermore, the above-mentioned "substituted" means substituted 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 group, or substituted by two or more substituents connected to each other among the substituents shown above, or having no substituent.

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

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031] The second object of the present invention is to provide an organic electroluminescent device, which comprises an organic layer; the organic layer contains the organic metal iridium complex as described above.

[0032] Specifically, the organic electroluminescent device comprises 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, and the light-emitting layer contains the organic metal iridium complex; and the organic metal iridium complex is used as a red light doping material.

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

[0035] By adding a phenyl group as a ligand at a fixed position on the azadibenzofuran in the organometallic iridium complex disclosed by the present invention, replacing the tert-butyl group on the naphthalene ring on the ligand, and adjusting the structural combination of the main ligand and the auxiliary ligand, the luminous efficiency and life of the organic electroluminescent device can be further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0037] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the organometallic iridium complex L-4. DETAILED DESCRIPTION

[0038] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the related drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

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

[0040] The specific embodiments described below are only part of the embodiments of the present application, rather than all the embodiments.

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

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

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

[0044]

[0045] The first step: Under a nitrogen protection system, weigh the raw material A-4 (CAS: 1354021-0902, 485 mmol), the 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, and add tetrakis(triphenylphosphine)palladium (9.7 mmol) to the system under a nitrogen environment. Reflux for 24 hours. After the reaction stops, the system is cooled to room temperature, and the liquid is separated by standing with ethyl acetate, and passed through a silica gel funnel and recrystallized 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 to the reaction system in sequence, the temperature was controlled at 0°C, tert-butyl nitrite (867 mmol) was slowly added dropwise to the system, and the reaction was continued for 48 hours. After the reaction was stopped, the system was cooled to room temperature, and the liquid was separated by standing with ethyl acetate, and the liquid was dried by spin drying. The liquid was passed through a silica gel funnel, and column chromatography was performed. Petroleum ether and dichloromethane were used as the developing agent, and the intermediate D-4 (33.4 g, yield 52.3%) was obtained by spin drying.

[0049] HPLC purity: ≥99%.

[0050]

[0051] Step 3: Under nitrogen conditions, weigh D-4 (149 mmol), E-4 (149 mmol, CAS: 2217657-10-6), potassium acetate (372 mmol), 1.4 dioxane (561 mL), add them into a three-necked flask in sequence, replace nitrogen twice, add bis(dibenzylideneacetone)palladium (1.49 mmol), 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (11.9 mmol) under nitrogen conditions, react at 100°C for 24 hours, cool to room temperature after the reaction is completed, spin dry the system, column chromatography, developing agents petroleum ether and ethyl acetate, spin dry to obtain intermediate F-4 (34.9 g, yield 63.5%).

[0052] HPLC purity: ≥99%.

[0053]

[0054] Step 4: Under nitrogen conditions, 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) and add them to the reaction system, replace the nitrogen twice, add tetrakistriphenylphosphine palladium (1.84 mmol) under nitrogen conditions, react at 100 ° C for 24 hours, cool to room temperature after the reaction is completed, separate with ethyl acetate, spin dry, column chromatography, developing agents petroleum ether and ethyl acetate, spin dry to obtain intermediate H-4 (28.3 g, yield 72.8%).

[0055] HPLC purity: ≥99%.

[0056]

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

[0058]

[0059] Step 6: Weigh the bridging ligand I-4 (8.3 mmol), potassium carbonate (166 mmol), and ethylene glycol ether (432 mL) and add them to the reaction system in sequence, replace the nitrogen twice, add 3,7-diethyl-3,7-dimethylnonane-4,6-dione (49.8 mmol) under nitrogen conditions, raise the temperature to 120°C and react for 36 hours. After the reaction is completed, filter, pass through a silica gel funnel, and spin dry to obtain the organometallic iridium complex L-4 (9.3 g, yield 43.6%).

[0060] Mass spectrum: Test 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 H NMR spectrum of L-4 is shown in Figure 1 .

[0066] Embodiment 2-10

[0067] The following compounds were synthesized by referring to the preparation method of Example 1 and tested by using a Waters XEVO TQD mass spectrometer, which has low precision. The ESI source was used for testing, and the mass spectrum 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 value L-8 <![CDATA[C7 9 H 79 IrN 2 O 4 ]]> 1312.61 L-9 <![CDATA[C 79 H 79 IrN 2 O 4 ]]> 1312.66 L-12 <![CDATA[C 79 H 79 IrN 2 O 4 ]]> 1312.75 L-19 <![CDATA[C 76 H 74 IrN 2 O 4 ]]> 1271.54 L-20 <![CDATA[C 78 H 78 IrN 2 O 4 ]]> 1299.61 L-29 <![CDATA[C 70 H 62 IrN 2 O 4 ]]> 1187.51 L-63 <![CDATA[C 76 H 74 IrN 2 O 4 ]]> 1271.56 L-69 <![CDATA[C 75 H 72 IrN 2 O 4 ]]> 1257.60 L-130 <![CDATA[C 75 H 72 IrN 2 O 4 ]]> 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 above-mentioned embodiments, so they are not listed one by one here.

[0071] Device Example 1: Preparation of organic electroluminescent device

[0072] The organic electroluminescent device is prepared by using the organic metal iridium complex formula L-4, and the specific process is as follows:

[0073] The coating thickness is The ITO glass substrate was washed twice in distilled water, ultrasonically washed for 30 minutes, and repeatedly washed twice with distilled water, ultrasonically washed for 10 minutes. After the distilled water washing, it was ultrasonically washed in isopropanol, acetone, and methanol solvents in sequence (once each, and each washing for 10 minutes) and then dried and transferred to a plasma cleaning machine. The above substrate was washed for 5 minutes and sent to a vapor deposition machine; ITO was used as the anode, and CuPc was first vapor-deposited on it. Then NPB was deposited A mixture of a main material 4,4'-N,N'-biphenyl dicarbazole ("CBP") and a compound of formula L-4 (wherein the weight ratio of 4,4'-N,N'-biphenyl dicarbazole ("CBP") to the compound L-4 is 95:5), an electron transport layer "Alq 3 ” Electron injection layer LiF Cathode Al The organic electroluminescent device L-4 was prepared.

[0074] The compounds used in the present invention are copper (II) phthalocyanine (CuPc), NPB, Alq 3 The structural formula of CBP is as follows:

[0075]

[0076] According to the above preparation scheme, formula L-4 is replaced with the organometallic iridium complexes in Table 2 in sequence to prepare the corresponding organic electroluminescent device.

[0077] Device comparison ratio:

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

[0079]

[0080] The luminescent characteristics of the organic electroluminescent devices obtained from the above device embodiments and device comparison examples were tested 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] It can be seen from Table 2 that at a current density of 10 mA / cm 2 By comparison, it can be seen that the absence of fluorine in the structure reduces the steric hindrance, making the product more soluble and thus significantly reducing the driving voltage of the device of the present invention. In the organic metal iridium complex disclosed in the present invention, a phenyl group is added as a ligand at a fixed position on the azadibenzofuran, and a tert-butyl group is replaced on the naphthalene ring on the ligand. By adjusting the structural combination of the main ligand and the auxiliary ligand, the current efficiency and life of the organic electroluminescent device can be further improved.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to 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, substituted or unsubstituted C1-C30 alkyl; R Z is selected from hydrogen, -CN, -D or -CD3.

2. The organometallic iridium complex according to claim 1, characterized in that R x and R y Each is independently selected from hydrogen, deuterium, and substituted or unsubstituted C1-C12 alkyl.

3. The organometallic iridium complex according to claim 2, characterized in that R x and R y Each is independently selected from hydrogen, deuterium, and any one of the following structures: Indicates the position where a substituent is attached.

4. The organometallic iridium complex according to claim 3, characterized in that R x and R y The groups may be partially or fully substituted by deuterium.

5. The organometallic iridium complex according to claim 1, characterized in that "Substituted" means substituted by one, two or more substituents selected from the group consisting of deuterium, cyano, deuterated methyl, C1-C6 alkyl, C3-C10 cycloalkyl, alkoxy, C6-C18 aryl, C3-C24 heterocyclyl, or substituted by two or more of the substituents shown above connected to each other, or having no substituent.

6. The organometallic iridium complex according to claim 1, characterized in that The structure of the organometallic iridium complex is selected from any one of the following compounds:

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an organic layer; the organic layer comprises the organic metal iridium complex according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic layer includes a light-emitting layer, and the light-emitting layer contains the organic metal iridium complex.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic metal iridium complex is used as a red light doping material.

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