An iridium metal complex and an organic optoelectric element using the same

Abstract

The present application belongs to the field of organic optoelectronics, and particularly relates to an iridium metal complex and an organic optoelectronic element containing the same, especially an organic electroluminescent diode, wherein the structure of the iridium metal complex is shown as formula (I): X in the iridium metal complex formula (I) is selected from NR 12 or O, and at least one is NR 12 ; other detailed information and the organic optoelectronic element can be understood by referring to the specific description provided herein. The iridium metal complex of the present application is applied to a light-emitting layer of an organic electroluminescent diode, so that the current efficiency of the light-emitting element is improved, the driving voltage is reduced, the service life is obviously prolonged, and the iridium metal complex has a good commercial prospect.

Description

Technical Field

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

[0002] Organic light-emitting diodes (OLEDs), as a new type of display technology, have unique advantages such as self-illumination, wide viewing angle, low energy consumption, high efficiency, thinness, rich colors, fast response speed, wide applicable temperature range, low driving voltage, the ability to make flexible, bendable and transparent display panels, and environmental friendliness. They can be used in flat panel displays and next-generation lighting, and can also be used as backlights for LCDs.

[0003] OLED light emission is divided into two types: fluorescence emission and phosphorescence emission. According to theoretical predictions, the ratio of singlet excited states to triplet excited states caused by the recombination of charges is 1:3. In 1998, Professors Baldo and Forrest et al. discovered that triplet phosphorescence can be utilized at room temperature, raising the upper limit of the internal quantum efficiency to 100%. Triplet phosphors are often complexes composed of heavy metal atoms. Utilizing the heavy atom effect, the strong spin-orbit coupling causes the energy levels of singlet and triplet excited states to mix, allowing the previously forbidden triplet energy to be released as phosphorescence, thus significantly improving the quantum efficiency.

[0004] Currently, almost all OLED components use a host-guest luminescent system, where a guest luminescent material is doped into the host material. Generally, the energy level of the organic host material is higher than that of the guest material, meaning energy is transferred from the host to the guest, exciting the guest material to emit light. Commonly used phosphorescent organic host materials, such as CBP (4,4′-bis(9-carbazolyl)-biphenyl), possess high efficiency and a high triplet energy level. When used as an organic material, triplet energy can be effectively transferred from the luminescent organic material to the guest phosphorescent material. Iridium metal compounds are commonly used organic guest materials, and their application in commercial OLED materials has become mainstream. However, some technical challenges remain, such as the requirement for high efficiency, longer lifespan, and lower operating voltage in OLEDs.

[0005] This invention discovers that expanding the conjugation of iridium metal compound ligands and introducing specific cyclic structures and substituents can improve the luminescence efficiency of iridium metal compounds. Under the premise of ensuring the thermal stability of iridium metal compounds, their application in organic optoelectronic components, especially in organic electroluminescent devices, can improve current efficiency, reduce the operating voltage of components, and extend lifespan. Summary of the Invention

[0006] The purpose of this invention is to provide an iridium metal complex and an optoelectronic device comprising the same, particularly an organic light-emitting diode.

[0007] The present invention provides an iridium metal complex structure as shown in formula (I):

[0008]

[0009] Where X is selected from NR 12 Or O, and at least one is NR. 12 Y is C, CY is a C5-C60 carbocyclic group or a C1-C60 heterocyclic group, and R, R1 to R 12 Independently selected from hydrogen, deuterium, CN, halogen, C1-C60 alkyl, C1-C60 alkoxy, containing C1-C60 alkylsilyl, containing C1-C60 alkoxysilyl, substituted or unsubstituted C2-C60 alkenyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C1-C60 heteroaryl, substituted or unsubstituted aryl ether, substituted or unsubstituted heteroaryl ether, substituted or unsubstituted arylamine, substituted or unsubstituted heteroarylamine, etc. The group can be any one of the following: substituted or unsubstituted arylsilyl group, substituted or unsubstituted heteroarylsilyl group, substituted or unsubstituted aryloxysilyl group, substituted or unsubstituted arylacyl group, substituted or unsubstituted heteroarylacyl group, or substituted or unsubstituted phosphine group; the heterocyclic group refers to the group containing at least one heteroatom from B, N, O, S, P (=O), Si, P; n is an integer from 0 to 10, and when n is 2 or greater, the two or more Rs are the same or different from each other; all groups can be partially or fully deuterated.

[0010] Preferably, the iridium metal complex formula (I) of the present invention is selected from one of the following representative structural formulas, but is not limited thereto:

[0011]

[0012] Among them, Y1, CY, O or N, R, R1 to R 13 n is the same as above.

[0013] Preferably, the iridium metal complex structure (I) of the present invention... Choose one of the following representative structures, but do not limit yourself to this one:

[0014]

[0015] In formulas A(1) to A(6), Y is C, X1 is O, S, N(R14), C(R14)(R15), Si(R14)(R15); X2 to X4 are CR14 or N; R14 to R18 are the same as R and R1 to R in claim 1. 12The same applies, where * represents the binding site with Ir in formula (I), and ** represents the binding site with the adjacent C in formula (I).

[0016] Preferably, in the iridium metal complex of the present invention, in formula (I) At least one of R2, R3, R4, R5, and R6 is F, and the rest are the same as those described in claims 1 to 3, but are not limited thereto.

[0017] Preferably, in the iridium metal complex of the present invention, R1 to R18 are independently selected from hydrogen, deuterium, CN, halogen, or one of the following representative structural formulas, but are not limited thereto:

[0018]

[0019] Preferably, the iridium metal complex of the present invention is selected from one of the following representative structural formulas, but is not limited thereto:

[0020]

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[0040]

[0041]

[0042] This invention relates to an iridium metal complex comprising the compound of formula (I) and one or more formulations formed with a solvent. The solvent used is not particularly limited and may be any solvent well known to those skilled in the art, such as unsaturated hydrocarbon solvents like toluene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, dicyclohexane, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, etc.; halogenated saturated hydrocarbon solvents like carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, etc.; halogenated unsaturated hydrocarbon solvents like chlorobenzene, dichlorobenzene, trichlorobenzene, etc.; ether solvents like tetrahydrofuran, tetrahydropyran, etc.; and ester solvents like alkyl benzoates.

[0043] The present invention also relates to an organic optoelectronic device, comprising: a first electrode;

[0044] The second electrode faces the first electrode.

[0045] An organic functional layer is sandwiched between the first electrode and the second electrode;

[0046] The organic functional layer contains the aforementioned iridium metal complex.

[0047] The present invention also relates to an organic electroluminescent device, comprising a cathode layer, an anode layer and an organic layer, wherein the organic layer comprises at least one of a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, an electron injection layer and an electron transport layer, wherein the light-emitting layer of the device contains the aforementioned iridium metal complex.

[0048] The organic electroluminescent device of the present invention contains the iridium metal complex and the corresponding host material in the light-emitting layer, wherein the mass percentage of the iridium metal complex is 0.1%-50%.

[0049] The organic electroluminescent device described in this invention is any one of organic photovoltaic devices, organic light-emitting devices (OLEDs), organic solar cells (OSCs), electronic paper (e-paper), organic photosensitive materials (OPCs), organic thin-film transistors (OTFTs), organic memory elements, lighting, and display devices.

[0050] In this invention, organic optoelectronic devices can be fabricated by depositing metals or conductive oxides and their alloys onto a substrate using methods such as sputtering, electron beam evaporation, and vacuum deposition to form the anode. A hole injection layer, hole transport layer, light-emitting layer, hole blocking layer, and electron transport layer are then sequentially deposited onto the surface of the anode, followed by the deposition of the cathode. Alternatively, organic electroluminescent devices can be fabricated by depositing the cathode, organic layer, and anode onto a substrate in that order. The organic layer can also include a multilayer structure comprising a hole injection layer, a hole transport layer, a light-emitting layer, a hole blocking layer, and an electron transport layer. In this invention, the organic layer is prepared using polymer materials via solvent engineering (spin-coating, tape-casting, doctor-blading, screen-printing, inkjet printing, or thermal imaging, etc.) instead of evaporation methods, which can reduce the number of device layers.

[0051] The materials used in the organic electroluminescent devices according to the present invention can be classified as top-emitting, bottom-emitting, or double-sided emitting. The compounds of the organic electroluminescent devices according to embodiments of the present invention can be applied to electroluminescent devices such as organic solar cells, OLEDs for lighting, flexible OLEDs, organic photosensitive materials, and organic thin-film transistors, based on principles similar to those of organic light-emitting devices.

[0052] The beneficial effects of this invention are:

[0053] The iridium metal compounds involved in this invention all have excellent thermal stability and good electron receiving ability, which can improve the energy transfer between the host and the guest. Specifically, organic electroluminescent devices made using the iridium metal compounds of this invention as functional layers, especially as light-emitting layers, have improved current efficiency, reduced start-up voltage, and significantly improved device lifetime. This indicates that after most electrons and holes recombine, the energy is effectively transferred to the iridium metal compounds for light emission. Attached Figure Description

[0054] Figure 1 This is a structural layer diagram of the organic light-emitting diode device of the present invention.

[0055] In this diagram, 110 represents the substrate, 120 represents the anode, 130 represents the hole injection layer, 140 represents the hole transport layer, 150 represents the light-emitting layer, 160 represents the hole blocking layer, 170 represents the electron transport layer, 180 represents the electron injection layer, and 190 represents the cathode. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0057] In a preferred embodiment of the present invention, the OLED device of the present invention includes a hole transport layer. The hole transport material can preferably be selected from known or unknown materials, and is particularly preferably selected from the following structures, but this does not mean that the present invention is limited to the following structures:

[0058]

[0059] In a preferred embodiment of the present invention, the hole transport layer in the OLED device of the present invention comprises one or more p-type dopants. The preferred p-type dopants of the present invention have the following structures, but this does not mean that the present invention is limited to these structures:

[0060]

[0061] In a preferred embodiment of the present invention, the electron transport layer may be selected from at least one of compounds ET-1 to ET-13, but this does not mean that the present invention is limited to the following structures:

[0062]

[0063] This invention also provides a formulation comprising the aforementioned composition and a solvent. The solvent used is not particularly limited and can be any solvent well-known to those skilled in the art, such as unsaturated hydrocarbon solvents like toluene, xylene, mesitylene, tetrahydronaphthalene, decahydronaphthalene, dicyclohexane, n-butylbenzene, sec-butylbenzene, tert-butylbenzene, etc.; halogenated saturated hydrocarbon solvents like carbon tetrachloride, chloroform, dichloromethane, dichloroethane, chlorobutane, bromobutane, chloropentane, bromopentane, chlorohexane, bromohexane, chlorocyclohexane, bromocyclohexane, etc.; halogenated unsaturated hydrocarbon solvents like chlorobenzene, dichlorobenzene, trichlorobenzene, etc.; ether solvents like tetrahydrofuran, tetrahydropyran, etc.; and ester solvents like alkyl benzoates. The formulation is directly used to prepare optoelectronic devices.

[0064] In the following text, based on existing literature and the inventor's relevant technical reserves, the general synthetic steps for the guest compounds involved in formula (I) are as follows:

[0065]

[0066] General steps,

[0067] (1) Under argon protection, a mixed solution of ligand 1 (0.10 mol), IrCl3·3H2O (0.045 mol), 2-ethoxyethanol (300 mL), and water (100 mL) was heated under reflux for 16–20 hours until the supernatant was collected. The content of ligand 1 was detected by high performance liquid chromatography as <5%. Heating was stopped, the temperature was lowered to room temperature, and the mixture was filtered through a Buchner funnel. The filter cake was washed with a mixture of water and 2-ethoxyethanol and dried to obtain a yellow powder of bridged dimer 2 or 3, with a yield of 81–89%.

[0068] (2) Under argon protection, a tetrahydrofuran solution of the dichloro cross-linked dimer complex (2.2 mmol) was added dropwise to the ligand. A lithium salt solution (2.4 mmol) was formed with butyllithium at -78°C. The solution was then slowly heated to room temperature and refluxed for 6 hours. Heating was stopped, the mixture was cooled to room temperature, and an appropriate amount of distilled water was added. The solid was filtered off. The solid was dissolved in dichloromethane and passed through a short silica gel column. The solvent was removed under reduced pressure, and the concentrated solid was washed successively with methanol and petroleum ether to obtain the final target product.

[0069] The preparation method of the iridium metal compound, i.e., the guest compound, and the luminescent properties of the device are explained in detail below with reference to the embodiments. Ligand 1 is obtained through custom synthesis. However, these are merely illustrative examples of embodiments of the present invention, and therefore the scope of the present invention is not limited thereto.

[0070] Example 1: Synthesis of Compound 1

[0071]

[0072] Following a common synthetic route, the yield was 65%. Mass spectrometry m / z: theoretical value 869.30; measured value M+H: 870.3.

[0073] Example 2: Synthesis of Compound 2

[0074]

[0075] Following the general synthetic route, the yield was 67%. Mass spectrometry m / z: theoretical value 882.33; measured value M+H: 883.3.

[0076] Example 3: Synthesis of Compound 3

[0077]

[0078] Following the general synthetic route, the yield was 76%. Mass spectrometry m / z: theoretical value 931.31; measured value M+H: 932.3.

[0079] Example 4: Synthesis of Compound 4

[0080]

[0081] Following the general synthetic route, the yield was 72%. Mass spectrometry m / z: theoretical value 1006.36; measured value M+H: 1007.3.

[0082] Example 5: Synthesis of Compound 5

[0083]

[0084] Following the general synthetic route, the yield was 78%. Mass spectrometry m / z: theoretical value 967.29; measured value M+H: 968.3.

[0085] Example 6: Synthesis of Compound 6

[0086]

[0087] Following a common synthetic route, the yield was 80%. Mass spectrometry m / z: theoretical value 967.29; measured value M+H: 968.3.

[0088] Example 7: Synthesis of Compound 7

[0089]

[0090] Following the general synthetic route, the yield was 71%. Mass spectrometry m / z: theoretical value 967.29; measured value M+H: 968.3.

[0091] Example 8: Synthesis of Compound 8

[0092]

[0093] Following the general synthetic route, the yield was 74%. Mass spectrometry m / z: theoretical value 967.29; measured value M+H: 968.3.

[0094] Example 9: Synthesis of Compound 9

[0095]

[0096] Following the general synthetic route, the yield was 63%. Mass spectrometry m / z: theoretical value 967.29; measured value M+H: 968.3.

[0097] Example 10: Synthesis of Compound 10

[0098]

[0099] Following the general synthetic route, the yield was 83%. Mass spectrometry m / z: theoretical value 1042.34; measured value M+H: 1043.3.

[0100] Example 11: Synthesis of Compound 11

[0101]

[0102] Following the general synthetic route, the yield was 81%. Mass spectrometry m / z: theoretical value 1042.34; measured value M+H: 1043.3.

[0103] Example 12: Synthesis of Compound 12

[0104]

[0105] Following the general synthetic route, the yield was 84%. Mass spectrometry m / z: theoretical value 1054.42; measured value M+H: 1055.4.

[0106] Example 13: Synthesis of Compound 13

[0107]

[0108] Following the general synthetic route, the yield was 82%. Mass spectrometry m / z: theoretical value 1055.42; measured value M+H: 1056.4.

[0109] Example 14: Synthesis of Compound 14

[0110]

[0111] Following a common synthetic route, the yield was 80%. Mass spectrometry m / z: theoretical value 1166.54; measured value M+H: 1167.5.

[0112] Example 15: Synthesis of Compound 15

[0113]

[0114] Following the general synthetic route, the yield was 78%. Mass spectrometry m / z: theoretical value 986.41; measured value M+H: 987.4.

[0115] Example 16: Synthesis of Compound 16

[0116]

[0117] Following the general synthetic route, the yield was 76%. Mass spectrometry m / z: theoretical value 1038.45; measured value M+H: 1039.4.

[0118] Example 17: Synthesis of Compound 17

[0119]

[0120] Following the general synthetic route, the yield was 72%. Mass spectrometry m / z: theoretical value 918.31; measured value M+H: 919.3.

[0121] Example 18: Synthesis of Compound 18

[0122]

[0123] Following a common synthetic route, the yield was 75%. Mass spectrometry m / z: theoretical value 1030.43; measured value M+H: 1031.4.

[0124] Manufacturing of OLED devices:

[0125] An organic light-emitting element (OLED) is fabricated by depositing p-doped materials P-1 to P-5 onto the surface or anode of an ITO / Ag / ITO glass with a light-emitting area of ​​2 mm × 2 mm, or by co-evaporating the p-doped materials with the compounds described in the table at a concentration of 1% to 50%. This forms a 5-100 nm hole injection layer (HIL) and a 5-200 nm hole transport layer (HTL). Subsequently, a 10-100 nm light-emitting layer (EML) (which may contain the compounds described) is formed on the hole transport layer. Finally, an electron transport layer (ETL) of 20-200 nm and a cathode of 50-200 nm are formed sequentially using the compounds described. If necessary, an electron blocking layer (EBL) is added between the HTL and EML layers, and an electron injection layer (EIL) is added between the ETL and the cathode. The OLEDs described are tested using standard methods and are listed in Table 1.

[0126] To better illustrate the actual gain effect of the present invention, OLED devices were fabricated using the following commonly used iridium metal complexes RD-1 to RD-3 as comparisons.

[0127]

[0128] In a specific embodiment, the OLED device structure is as follows: on a glass containing ITO / Ag / ITO, HIL is HT-1:P-3 (95:5v / v%) with a thickness of 10 nm; HTL is HT-1 with a thickness of 90 nm; EBL is HT-8 with a thickness of 10 nm; EML is H-1:iridium metal compound (97:3v / v%) with a thickness of 35 nm; ETL is ET-13:LiQ (50:50v / v%) with a thickness of 35 nm; and then a cathode of 1 nm Yb and 14 nm Ag are deposited by vapor deposition. The current efficiency, voltage, and lifetime characteristics based on the above embodiment and comparative examples are shown in Table 1 below.

[0129] Based on the above embodiments and comparative examples, the efficiency, driving voltage, lifespan, and other characteristics are shown in Table 1 below.

[0130] Table 1

[0131]

[0132] As shown in Table 1, by incorporating a benzene ring into the ligand structure and changing the auxiliary ligand, devices 1 and 2, compared to comparative device 1, exhibit efficiencies more than 30% higher than comparative device 3, with significant improvements in both efficiency and lifetime. Compared to comparative device 2, the metal complexes obtained using the auxiliary ligand in this invention, devices 3 to 16, using the iridium metal compound provided by this invention as the guest material, can significantly improve the current efficiency of OLED devices and reduce the driving voltage, while also showing a corresponding increase in lifetime. Most notably, device 8, which differs from comparative device 2 only in the auxiliary ligand, achieves a current efficiency of 110% of that of comparative device 2, a 0.2-volt decrease in operating voltage, and a 46% increase in lifetime. Particularly outstanding, device 11 shows an 18% increase in efficiency and a 93% increase in lifetime compared to comparative device 2. This demonstrates that the iridium metal complexes provided by this invention have significant advantages and commercial application value.

[0133] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. An iridium metal complex selected from one of the following representative structural formulas: 。 2. A formulation, characterized in that, It comprises the iridium metal complex of claim 1 and at least one solvent.

3. An organic optoelectronic device, characterized in that, include: First electrode; The second electrode faces the first electrode. An organic functional layer is sandwiched between the first electrode and the second electrode; The organic functional layer comprises the iridium metal complex as described in claim 1.

4. An organic optoelectronic device, comprising a cathode layer, an anode layer, and an organic layer, wherein the organic layer comprises at least one of a hole injection layer, a hole transport layer, a light-emitting layer or an active layer, an electron injection layer, and an electron transport layer, characterized in that: The device contains the iridium metal complex as described in claim 1 in any layer.

5. The organic optoelectronic device according to claim 3, characterized in that, Organic optoelectronic devices include organic photovoltaic devices, organic light-emitting devices, organic solar cells, electronic paper, organic photosensitive materials, organic thin-film transistors and organic memory devices, lighting and display devices.

6. The organic optoelectronic element according to claim 4 is an organic electroluminescent device, characterized in that, The light-emitting layer contains the iridium metal complex as described in claim 1 and the corresponding host material, wherein the iridium metal complex has a mass percentage of 1% to 50%, and the host material is not limited.

7. A display or lighting device, characterized in that, The display or lighting device described herein contains the organic optoelectronic device as described in claim 3.

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