Iridium complex and preparation method thereof, and organic light-emitting device

Abstract

The invention discloses an iridium complex and a preparation method thereof, and an organic light-emitting device, and belongs to the field of display technology. The chemical structural formula of the iridium complex is as follows: #imgabs0# Ring A is a substituted or unsubstituted aromatic ring or heteroaromatic ring with 6-30 carbon atoms; R1-R7 are hydrogen, deuterium, fluorine, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl; R 11 ~R 13 The iridium complex has excellent red light saturation, luminous efficiency and thermal stability.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to an iridium complex and a preparation method thereof, and an organic light-emitting device. Background Art

[0002] Organic Light Emitting Diodes (OLED) is a semiconductor light-emitting device based on organic light-emitting materials. OLED devices include a light-emitting layer based on light-emitting materials. The type of light emitted can be adjusted by changing the light-emitting materials. Phosphorescent materials can effectively utilize triplet excitons. Compared with fluorescent materials, their internal quantum efficiency can theoretically be increased from 25% to 100%.

[0003] Currently common phosphorescent materials include red phosphorescent materials, green phosphorescent materials and blue phosphorescent materials. Among them, iridium complexes are widely used organic electroluminescent phosphorescent materials due to their good phosphorescent emission, high phosphorescent emission efficiency, wide emission spectrum and strong stability.

[0004] However, due to the larger conjugated groups and enhanced intermolecular interactions of red iridium complexes, the luminescence efficiency and luminescence effect need to be improved due to factors such as their smaller energy gap and host material matching. On the other hand, red iridium complexes also face the problem of color purity. With the rapid development of the organic electroluminescent device industry and more potential applications, such as fingerprint recognition, probes, life detection, and beauty, the emission wavelength is greater than 630, and the deep red light is less, so there is still a need to develop efficient and deep red phosphorescent materials. Summary of the invention

[0005] In view of this, the embodiments of the present invention provide an iridium complex and a preparation method thereof, and an organic light-emitting device, which can solve the above technical problems.

[0006] Specifically, the following technical solutions are included:

[0007] In one aspect, an iridium complex is provided, the chemical structural formula of the iridium complex is as follows:

[0008]

[0009] Wherein, Ring A is a substituted or unsubstituted aromatic ring or heteroaromatic ring having 6 to 30 carbon atoms;

[0010] R1-R7 are each independently hydrogen, deuterium, fluorine, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl;

[0011] R11 ~R 13 Each is independently hydrogen, deuterium, fluorine, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl;

[0012] At least one of R1 to R7 is an oxygen-containing heterocycle, and the oxygen-containing heterocycle includes at least four carbon atoms.

[0013] In some possible implementations, the oxygen-containing heterocycle is a substituted or unsubstituted C4-C20 saturated oxygen-containing heterocycle.

[0014] In some possible implementations, the saturated oxygen-containing heterocycle is a substituted or unsubstituted tetrahydrofuranyl or tetrahydropyranyl.

[0015] In some possible implementations, the oxygen-containing heterocycle is a substituted or unsubstituted C4-C20 unsaturated oxygen-containing heterocycle.

[0016] In some possible implementations, the unsaturated oxygen-containing heterocycle contains at least one carbon-carbon double bond.

[0017] In some possible implementations, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted pyranyl, a substituted or unsubstituted dihydropyranyl, a substituted or unsubstituted furanyl, or a substituted or unsubstituted dihydrofuranyl.

[0018] In some possible implementations, R1 to R6 are all hydrogen; (R7) n At least one of them is the oxygen-containing heterocycle, wherein n≥1.

[0019] In some possible implementations, one of R1 to R6 is a first non-hydrogen group, and the others are hydrogen;

[0020] The first non-hydrogen group and (R7) n At least one of them is the oxygen-containing heterocycle, wherein n≥0.

[0021] In some possible implementations, two of R1 to R6 are second non-hydrogen groups, and the rest are hydrogen, the two second non-hydrogen groups are located on different rings, and at least one of the two second non-hydrogen groups is from R3 to R5;

[0022] two of the second non-hydrogen groups and (R7) n At least one of them is the oxygen-containing heterocycle, wherein n≥0.

[0023] In some possible implementations, two of R1 to R6 are third non-hydrogen groups, and the rest are hydrogen, and the two third non-hydrogen groups are located on the same ring;

[0024] two of the third non-hydrogen groups and (R7) n At least one of them is the oxygen-containing heterocycle, wherein n≥0.

[0025] In some possible implementations, at least three of R1 to R6 are fourth non-hydrogen groups, and the rest are hydrogen;

[0026] at least three of the fourth non-hydrogen groups and (R7) n At least one of them is the oxygen-containing heterocycle, wherein n≥0.

[0027] In some possible implementations, at least one of R3 to R5 and R7 is the oxygen-containing heterocycle.

[0028] On the other hand, a method for preparing an iridium complex is provided, wherein the iridium complex is any one of the above items;

[0029] The preparation method of the iridium complex comprises:

[0030] providing a first ligand compound and a second ligand compound;

[0031] The first ligand compound, the second ligand compound and potassium carbonate or sodium carbonate are stirred and reacted in a solvent to obtain the iridium complex;

[0032] Wherein, the chemical structural formula of the first ligand compound is as follows:

[0033]

[0034] The chemical structural formula of the second ligand compound is as follows:

[0035]

[0036] In another aspect, an organic light-emitting device is provided. The organic light-emitting device comprises a light-emitting layer. A raw material for preparing the light-emitting layer comprises any one of the above-mentioned iridium complexes.

[0037] The beneficial effects of the technical solution provided by the embodiment of the present invention include at least:

[0038] The iridium complex provided by the embodiment of the present invention makes at least one of R1 to R7 an oxygen-containing heterocycle, and the oxygen-containing heterocycle includes at least four carbon atoms. Based on the oxygen-containing heterocycle, it is used in the iridium complex to adjust the luminescent color and increase the luminescent wavelength, which not only makes the iridium complex material have better red light saturation, color purity and luminescent efficiency, but also can improve the thermal stability of the iridium complex material. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0040] Figure 1 A schematic structural diagram of an exemplary organic light-emitting device provided in an embodiment of the present invention;

[0041] Figure 2 This is the hydrogen nuclear magnetic resonance spectrum of the iridium complex RD5.

[0042] The reference numerals represent:

[0043] 1- anode, 2- hole injection layer, 3- hole transport layer, 4- electron blocking layer, 5- light emitting layer, 6- electron transport layer, 7- electron injection layer, 8- cathode. DETAILED DESCRIPTION

[0044] In order to make the technical solutions and advantages of the present application more clear, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0045] Organic Light Emitting Diodes (OLED) is a semiconductor light-emitting device based on organic light-emitting materials. OLED devices include at least a hole transport layer, a light-emitting layer, and an electron transport layer. Holes generated by the anode pass through the hole transport layer to the light-emitting layer, and electrons generated by the cathode pass through the electron transport layer to the light-emitting layer. Holes and electrons form excitons in the light-emitting layer to emit light. The type of light emitted can be adjusted by changing the light-emitting material.

[0046] Generally, 25% of the excitons are in the singlet excited state, and the remaining 75% are in the triplet excited state. The radiative transition pathways corresponding to these two types of excitons are singlet fluorescence and triplet phosphorescence, respectively. Phosphorescent materials can effectively utilize triplet excitons. Compared with fluorescent materials, theoretically, the internal quantum efficiency of phosphorescent materials can be increased from 25% to 100%. Therefore, high-efficiency phosphorescent organic electroluminescent devices have been focused on so that they can be used in devices such as flat panels and portable display devices.

[0047] Common phosphorescent materials currently include red phosphorescent materials, green phosphorescent materials and blue phosphorescent materials, among which iridium complexes are a widely used organic electroluminescent phosphorescent material. The atomic number of iridium is relatively large, which makes the iridium complex produce strong spin-orbit coupling, which is conducive to phosphorescent emission; the d orbital energy level splitting in the iridium metal ion is large, which can avoid the metal-ligand charge transfer (MLCT) state interaction with the ligand, which is conducive to improving the phosphorescent emission efficiency; the trivalent ion of iridium can form a very stable neutral molecule with the ligand, making it conducive to the preparation of light-emitting devices by vacuum evaporation or solution processing. The color of the emission light of the iridium complex can cover the entire visible spectrum, and it has good stability, which meets the requirements of electroluminescent materials. It can be seen that based on the advantages of good phosphorescent emission, high phosphorescent emission efficiency, wide emission spectrum and strong stability of iridium complexes, it has become the research focus of organic electroluminescent phosphorescent materials.

[0048] However, due to the larger conjugated groups and enhanced intermolecular interactions of red iridium complexes, the luminescence efficiency and luminescence effect need to be improved due to factors such as the smaller energy gap and the matching of the main materials. On the other hand, red iridium complexes also face the problem of color purity. With the rapid development of the organic electroluminescent device industry and more potential applications, such as fingerprint recognition, probes, life detection, and beauty, the emission wavelength is greater than 630nm, and the deep red light is less, so there is still a need to develop efficient and deep red phosphorescent materials.

[0049] The embodiment of the present invention provides an iridium complex, and the chemical structural formula of the iridium complex is as follows:

[0050]

[0051] Wherein, Ring A is a substituted or unsubstituted aromatic ring or heteroaromatic ring having 6 to 30 carbon atoms;

[0052] R1 to R7 are each independently hydrogen, deuterium, fluorine, cyano, substituted or unsubstituted C1 to C20 alkyl, substituted or unsubstituted C3 to C20 cycloalkyl, substituted or unsubstituted C6 to C30 aryl, or substituted or unsubstituted C3 to C30 heteroaryl. Any two of R1 to R7 may be the same or different.

[0053] R 11 ~R 13 Each is independently hydrogen, deuterium, fluorine, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl. 11 ~R 13 Any two of them can be the same or different.

[0054] The above-mentioned substituted or unsubstituted C1~C20 alkyl group refers to the alkyl group having 1-20 carbon atoms. When the C1~C20 alkyl group includes a substituent, the substituent may be an alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic, aryl or heteroaryl group, and the substituents may be unsubstituted or substituted with one or more of the following groups: at least one of deuterium, halogen, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl and phosphino.

[0055] The above-mentioned substituted or unsubstituted C3~C20 cycloalkyl group refers to a cycloalkyl group having 1-20 carbon atoms. When the C3~C20 cycloalkyl group includes a substituent, the substituent may be an alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic, aryl or heteroaryl group, and the substituents may be unsubstituted or substituted with one or more of the following groups: at least one of deuterium, halogen, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl and phosphino.

[0056] The above-mentioned substituted or unsubstituted C6~C30 aryl group refers to that the number of carbon atoms contained in the aryl group is 6-30. When the C6~C30 aryl group includes a substituent, the substituent may be an alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic, aryl or heteroaryl group, and these substituents may be unsubstituted or substituted with one or more of the following groups: at least one of deuterium, halogen, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl and phosphino.

[0057] The above-mentioned substituted or unsubstituted C3~C30 heteroaryl group refers to a heteroaryl group having 3-30 carbon atoms. When the C3~C30 heteroaryl group includes a substituent, the substituent may be an alkyl, cycloalkyl, alkenyl, alkynyl, aralkyl, heterocyclic, aryl or heteroaryl group, and the substituents may be unsubstituted or substituted with one or more of the following groups: deuterium, halogen, alkyl, cycloalkyl, aralkyl, alkoxy, aryloxy, amino, cyclic amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acid, ether, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl and phosphino.

[0058] For (R7)n , n R7 are all connected to ring A. When R7 is hydrogen, R7 can be considered to be subordinate to ring A. When R7 is a non-hydrogen group, R7 can be considered to be a substituent on ring A. Wherein n is a positive integer, and the maximum value of n is less than or equal to the number of substitutable positions on ring A. When n≥2, R7 can be the same or different. In some examples, n is a positive integer of 0-10, for example, 0, 1, 2, 3, 4, 5, 6, etc.

[0059] In particular, the iridium complex provided by the embodiment of the present invention makes at least one of R1 to R7 an oxygen-containing heterocycle, and the oxygen-containing heterocycle includes at least four carbon atoms. Based on the oxygen-containing heterocycle, it is used in the iridium complex to adjust the luminescent color and increase the luminescent wavelength, which not only makes the iridium complex material have better red light saturation, color purity and luminescent efficiency, but also can improve the thermal stability of the iridium complex material.

[0060] In some examples, the iridium complex includes only one oxygen-containing heterocycle; in other examples, the iridium complex includes two or more oxygen-containing heterocycles, and the multiple oxygen-containing heterocycles may be the same, different from each other, or partially different.

[0061] The oxygen-containing heterocycle involved in the embodiment of the present invention includes a saturated oxygen-containing heterocycle and an unsaturated oxygen-containing heterocycle, wherein the saturated oxygen-containing heterocycle may be substituted or unsubstituted, and the unsaturated oxygen-containing heterocycle may be substituted or unsubstituted. Exemplarily, the oxygen-containing heterocycle involved in the embodiment of the present invention is a substituted or unsubstituted saturated oxygen-containing heterocycle.

[0062] In some implementations, the oxygen-containing heterocycle is a substituted or unsubstituted C4-C20 saturated oxygen-containing heterocycle, further, a substituted or unsubstituted C4-C12 saturated oxygen-containing heterocycle, further, a substituted or unsubstituted saturated C4-C9 oxygen-containing heterocycle, and still further, a substituted or unsubstituted saturated C4-C5 oxygen-containing heterocycle.

[0063] For example, the oxygen-containing heterocycle is a substituted or unsubstituted saturated C4 oxygen-containing heterocycle, or a substituted or unsubstituted saturated C5 oxygen-containing heterocycle.

[0064] Illustratively, the saturated oxygen-containing heterocycle is substituted or unsubstituted tetrahydrofuranyl or tetrahydropyranyl.

[0065] In some embodiments, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C4-C20 oxygen-containing heterocycle containing at least one carbon-carbon double bond, further, a substituted or unsubstituted C4-C16 oxygen-containing heterocycle containing at least one carbon-carbon double bond, further, a substituted or unsubstituted C4-C13 oxygen-containing heterocycle containing at least one carbon-carbon double bond, further, a substituted or unsubstituted C4-C9 oxygen-containing heterocycle containing at least one carbon-carbon double bond, further, a substituted or unsubstituted C4-C5 oxygen-containing heterocycle containing at least one carbon-carbon double bond, and further, a substituted or unsubstituted C4 oxygen-containing heterocycle containing one or two carbon-carbon double bonds.

[0066] In some examples, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C5 oxygen-containing heterocycle containing at least one carbon-carbon double bond.

[0067] In some examples, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C9 oxygen-containing heterocycle containing at least one carbon-carbon double bond.

[0068] In some examples, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C12 oxygen-containing heterocycle containing at least one carbon-carbon double bond.

[0069] In some examples, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C13 oxygen-containing heterocycle containing at least one carbon-carbon double bond.

[0070] In some examples, the unsaturated oxygen-containing heterocycle is a substituted or unsubstituted C15 oxygen-containing heterocycle containing at least one carbon-carbon double bond.

[0071] For the number of carbon-carbon double bonds contained in the unsaturated oxygen-containing heterocycle, see the following examples:

[0072] In some examples, the unsaturated oxygen-containing heterocycle contains at least one carbon-carbon double bond, for example, one carbon-carbon double bond.

[0073] In some examples, the unsaturated oxygen-containing heterocycle contains at least two carbon-carbon double bonds, for example, two carbon-carbon double bonds.

[0074] Illustratively, the unsaturated oxygen-containing heterocycle comprises substituted or unsubstituted pyranyl, substituted or unsubstituted dihydropyranyl, substituted or unsubstituted furanyl, substituted or unsubstituted dihydrofuranyl.

[0075] The term "substituted" in the oxygen-containing heterocycle may refer to substitution with a C1-C3 saturated alkyl group, substitution with a halogen group, or substitution with a C3-C30 saturated or unsaturated phenyl group, cycloalkyl group or heterocyclic group.

[0076] In particular, the iridium complex provided by the embodiment of the present invention contains an oxygen-containing heterocycle with a double bond, which can further optimize the red light saturation, luminous efficiency and thermal stability of the iridium complex, and can also enhance the film-forming property of the iridium complex, and because the conjugated structure in the iridium complex is increased, the red light saturation and luminous efficiency of the iridium complex are further optimized. When the number of unsaturated oxygen-containing heterocycles increases, the red light saturation is further improved and the luminous wavelength is further red-shifted.

[0077] The inventors have found that by adjusting the substitution position of the oxygen-containing heterocycle in the iridium complex, that is, the specific substitution position of the oxygen-containing heterocycle is which of the positions R1 to R7 is located, it is of great significance to increase the luminous wavelength of the iridium complex, make it show a purer light color and better color saturation, and improve the luminous efficiency.

[0078] The following are some exemplary descriptions of some implementation methods that can achieve the above-mentioned effects of optimizing the iridium complex, wherein the "non-hydrogen substituent" referred to below refers to deuterium, fluorine, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, or substituted or unsubstituted C3-C30 heteroaryl.

[0079] (1) In some examples, R1 to R6 are all hydrogen, (R7) n At least one of them is an oxygen-containing heterocycle, wherein n≥1.

[0080] For example, when the number of oxygen-containing heterocyclic rings is greater than or equal to 1 and less than or equal to n-1, (R7) n In the above, except for those containing oxygen-containing heterocycles, the remaining R7 may be hydrogen, a non-hydrogen substituent, or a combination of hydrogen and non-hydrogen substituents.

[0081] (2) In some examples, one of R1 to R6 is a first non-hydrogen group, and the others are hydrogen, and the first non-hydrogen group and (R7) n At least one of them is an oxygen-containing heterocycle, wherein n≥0.

[0082] For example, when the number of the oxygen-containing heterocyclic ring is one, the oxygen-containing heterocyclic ring may be from R1 to R6, or the oxygen-containing heterocyclic ring may be from (R7) n .

[0083] When the number of the oxygen-containing heterocyclic rings is multiple (ie, two or more), one of the oxygen-containing heterocyclic rings may be derived from R1 to R6, and the remaining oxygen-containing heterocyclic rings may be derived from (R7). n , or, all oxygen-containing heterocycles are derived from (R7) n .

[0084] For the first non-hydrogen group mentioned above, when it is not an oxygen-containing heterocycle, the first non-hydrogen group is a non-hydrogen substituent.

[0085] For the above (R7) n , when it does not include an oxygen-containing heterocycle, these R7 may be hydrogen, non-hydrogen substituents, or a combination of hydrogen and non-hydrogen substituents. When it includes an oxygen-containing heterocycle, except for those R7 that are oxygen-containing heterocycles, the remaining R7 may be hydrogen, non-hydrogen substituents, or a combination of hydrogen and non-hydrogen substituents.

[0086] (3) In some examples, for R1 to R6, two of R1 to R6 are second non-hydrogen groups, and the rest are hydrogen, the two second non-hydrogen groups are located on different rings, and at least one of the two second non-hydrogen groups is from R3 to R5. The two second non-hydrogen groups and (R7) n At least one of them is an oxygen-containing heterocycle, wherein n≥0.

[0087] For example, one of the second non-hydrogen groups is from R3-R5, and the other second non-hydrogen group is from R1-R2 or R6, or both second non-hydrogen groups are from R3-R5.

[0088] For the second non-hydrogen group, if the current second non-hydrogen group is not an oxygen-containing heterocycle, the current second non-hydrogen group is a non-hydrogen substituent.

[0089] For the above (R7) n When it does not include an oxygen-containing heterocycle, these R7 can be hydrogen, a non-hydrogen substituent, or a combination of hydrogen and non-hydrogen substituents. When (R7) n When an oxygen-containing heterocycle is included, the remaining R7 except for those R7 that are oxygen-containing heterocycles may be hydrogen, may be a non-hydrogen substituent, or may be a combination of hydrogen and non-hydrogen substituents.

[0090] (4) In some examples, for R1 to R6, two of R1 to R6 are third non-hydrogen groups, and the rest are hydrogen, and the two third non-hydrogen groups are located on the same ring. The two third non-hydrogen groups and (R7) n At least one of them is an oxygen-containing heterocycle, wherein n≥0.

[0091] For example, the two third non-hydrogen groups are from R1 to R2, or the two third non-hydrogen groups are from R3 to R6.

[0092] For the third non-hydrogen group, if the third non-hydrogen group is not an oxygen-containing heterocycle, the third non-hydrogen group is a non-hydrogen substituent.

[0093] For the above (R7) nWhen it does not include an oxygen-containing heterocycle, these R7 can be hydrogen, a non-hydrogen substituent, or a combination of hydrogen and non-hydrogen substituents. When (R7) n When an oxygen-containing heterocycle is included, the remaining R7 except for those R7 that are oxygen-containing heterocycles may be hydrogen, may be a non-hydrogen substituent, or may be a combination of hydrogen and non-hydrogen substituents.

[0094] (5) In some examples, for R1 to R6, at least three of R1 to R6 are fourth non-hydrogen groups, and the rest are hydrogen, and at least three fourth non-hydrogen groups and (R7) n At least one of them is an oxygen-containing heterocycle, wherein n≥0, and further, n≥1.

[0095] For the fourth non-hydrogen group, if the current fourth non-hydrogen group is not an oxygen-containing heterocycle, the current fourth non-hydrogen group is a non-hydrogen substituent.

[0096] For the above (R7) n When it does not include an oxygen-containing heterocycle, these R7 can be hydrogen, a non-hydrogen substituent, or a combination of hydrogen and non-hydrogen substituents. When (R7) n When oxygen-containing heterocycles are included, except for those R 7n The remaining R7 may be hydrogen, a non-hydrogen substituent, or a combination of hydrogen and non-hydrogen substituents.

[0097] The iridium complex provided by the embodiment of the present invention makes at least one of R3 to R5 and R7 be the oxygen-containing heterocycle, that is, the substitution position of the oxygen-containing heterocycle is at least one of R3 to R5 and R7. This arrangement further increases the luminous wavelength of the iridium complex, red-shifts more, displays a deeper red, and improves the color effect.

[0098] For example, the iridium complex provided by the embodiment of the present invention includes but is not limited to the following. In the chemical structure of the following iridium complex, the solid line connected to Ir is the solid line with an arrow mentioned above, and the dotted line connected to Ir is the solid line without an arrow mentioned above:

[0099]

[0100]

[0101]

[0102]

[0103]

[0104] The iridium complex provided by the present invention designs an oxygen-containing heterocycle at a specific substitution position, and makes the oxygen-containing heterocycle a pyran structure or a furan structure. The oxygen-containing heterocycle at the substitution position defined by the present invention can adjust the luminescence color, improve the thermal stability of the iridium complex, and enhance the luminescence efficiency of the iridium complex.

[0105] In addition, the iridium complex having the above oxygen-containing heterocycle has a large steric hindrance, which can reduce the interaction between luminescent molecules and reduce the probability of luminescence quenching. Taking the above factors into consideration, when the iridium complex provided by the embodiment of the present invention is used in an organic light-emitting device, the luminous efficiency of the organic light-emitting device can be significantly improved, and the color saturation and luminescence purity of the organic light-emitting device can be significantly improved.

[0106] On the other hand, an embodiment of the present invention further provides a method for preparing an iridium complex, the method for preparing the iridium complex comprising:

[0107] A first ligand compound and a second ligand compound are provided.

[0108] The first ligand compound, the second ligand compound and potassium carbonate or sodium carbonate are stirred and reacted in a solvent to obtain an iridium complex.

[0109] Wherein, the chemical structural formula of the first ligand compound is as follows:

[0110]

[0111] The chemical structure of the second ligand compound is shown below:

[0112]

[0113] Exemplarily, the first ligand compound, the second ligand compound and potassium carbonate are added to a reactor, then dissolved with a solvent, and stirred at room temperature to react to obtain an iridium complex. For example, the solvent includes but is not limited to ethylene glycol ethyl ether.

[0114] In addition, for the preparation of the first ligand compound, please refer to the preparation process of intermediate 5 shown in Example 1 below. According to the specific type of oxygen-containing heterocycle, the type of oxygen-containing heterocycle donor compound (such as tetrahydropyrone) can be adaptively adjusted, and according to the specific position of the oxygen-containing heterocycle, the position of the halogen atom can be adaptively adjusted.

[0115] In another aspect, an embodiment of the present invention further provides an organic light-emitting device, which includes a light-emitting layer, and a raw material for preparing the light-emitting layer includes the above-mentioned iridium complex.

[0116] The organic light-emitting device provided in the embodiment of the present invention can emit red light. Based on the use of the above-mentioned iridium complex including oxygen-containing heterocycles, the luminous efficiency of the organic light-emitting device is significantly improved, and the color saturation and luminous purity of the organic light-emitting device are significantly improved.

[0117] The iridium complex can be used as an emitting dopant in the light-emitting layer, and synergizes with the main light-emitting material in the light-emitting layer to achieve light emission. In some examples, the mass ratio of the main light-emitting material to the iridium complex is 15 to 25:1, for example, 17:1, 18:1, 19:1, 20:1, 21:1, etc.

[0118] Exemplarily, the main light-emitting material includes at least one of the following groups: triphenylene, carbazole, dibenzothiophene, dibenzofuran, dibenzoselenophene, azatriphenylene, azacarbazole, aza-dibenzothiophene, aza-dibenzofuran, aza-dibenzoselenophene.

[0119] For example, some suitable host luminescent materials include but are not limited to the following compounds:

[0120]

[0121]

[0122] The organic light-emitting device provided in the embodiment of the present invention includes an anode, a cathode and an organic layer, wherein the organic layer at least includes a light-emitting layer, and the organic layer may further include at least one of a hole injection layer, a hole transport layer, a hole blocking layer, an electron injection layer, and an electron transport layer.

[0123] For example, if Figure 1 As shown, the organic light-emitting device provided by the embodiment of the present invention includes an anode 1, a hole injection layer 2, a hole transport layer 3, an electron blocking layer 4, a light-emitting layer 5, an electron transport layer 6, an electron injection layer 7 and a cathode 8 stacked in sequence from bottom to top, wherein the anode 1 is formed on a substrate, and the substrate can be, for example, a glass substrate, a ceramic substrate, etc.

[0124] The anode 1, the hole injection layer 2, the hole transport layer 3, the electron blocking layer 4, the electron transport layer 6, the electron injection layer 7 and the cathode 8 are each made of materials commonly used in the art, and are described exemplarily below:

[0125] As for the anode 1 , the anode 1 includes but is not limited to the following: indium tin oxide (ITO) conductive glass, Au, transparent conductive polymer (such as polyaniline, etc.), etc.

[0126] As for the hole injection layer 2, it includes but is not limited to: MoO3, F4TCNQ, HAT(CN)6 and the like.

[0127] The hole transport layer 3 includes, but is not limited to, N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB for short) and 4,4'-cyclohexylbis[N,N-di(4-methylphenyl)aniline] (TAPC for short).

[0128] The electron blocking layer 4 includes, but is not limited to, aromatic polyamine compounds, such as 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA for short).

[0129] The electron transport layer 6 includes, but is not limited to, 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI for short), 1,3,5-tris[(3-pyridyl)-3-phenyl]benzene (TmPyPB for short), and the like.

[0130] The electron injection layer 7 includes, but is not limited to, LiF, 8-hydroxyquinolinolato-lithium (8-Hydroxyquinolinolato-lithium, LiQ) and the like.

[0131] As for the cathode 8, the cathode 8 includes but is not limited to the following: a single-layer metal cathode (such as Ag, Al, Li, Mg, Ca, In, etc.), an alloy cathode (such as a Mg-Ag alloy cathode, a Li-Al alloy electrode, etc.), a layered cathode, etc.

[0132] The chemical structural formulas of some of the compounds mentioned above are as follows:

[0133]

[0134] The hole injection layer 2, hole transport layer 3, electron blocking layer 4, light-emitting layer 5, electron transport layer 6 and electron injection layer 7 can be formed by coating methods commonly used in the art, for example, including but not limited to: vacuum evaporation, molecular beam evaporation, solvent-dissolved dip coating, spin coating, rod coating or inkjet printing, etc.

[0135] The anode 1 and the cathode 8 may also be formed by a coating method commonly used in the art, for example including but not limited to: evaporation method or sputtering method.

[0136] Illustratively, the organic light-emitting device provided by the embodiments of the present invention can be used in any of the following electronic devices for display or light emission: computers, tablet computers, televisions, phones, virtual reality or augmented reality displays, etc.

[0137] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. In the embodiment, if no specific technology or conditions are indicated, the technology or conditions described in the document in this area or the product specification are carried out. If the manufacturer is not indicated for reagents used or instruments, they are all conventional products that can be obtained commercially.

[0138] Example 1

[0139] This embodiment 1 provides an iridium complex, the chemical structural formula of which is shown in the above-mentioned RD5. The preparation formula of the iridium complex RD5 is as follows:

[0140]

[0141]

[0142] Combined with the preparation formula of the above iridium complex RD5, the preparation steps of the iridium complex RD5 are as follows:

[0143] Step 1: Synthesis of intermediate 1

[0144] Add 31.56g of magnesium chips and 1 iodine (used as an initiator) to a four-necked bottle, and replace the air in the bottle with nitrogen. Dissolve 306.32g of p-dibromobenzene in 1L of tetrahydrofuran to form a p-dibromobenzene solution, add the p-dibromobenzene solution to a constant pressure dropping funnel, and drop 50mL of p-dibromobenzene solution into the four-necked bottle under stirring at room temperature. During the reaction, it was observed that the color of the reaction system solution turned brownish yellow, and stirring was continued until the color of iodine faded. When the reaction system solution became colorless, the four-necked bottle was placed in an ice-water bath and stirred, and then the p-dibromobenzene solution was slowly added to the four-necked bottle, and the temperature of the reaction system was controlled not to exceed 15°C. After the p-dibromobenzene solution was added, the reaction system continued to stir in an ice-water bath for 1h.

[0145] Then, 130 g of tetrahydropyrone was dissolved in 0.5 L of tetrahydrofuran to form a tetrahydropyrone solution, which was added to a constant pressure dropping funnel and dripped into a four-necked flask, and the reaction was continued for 1 h. The ice-water bath was removed, and the remaining tetrahydropyrone solution was quickly dripped, and the temperature of the reaction system was controlled to be 30° C.-50° C. After the tetrahydropyrone solution was dripped, the reaction was kept in a water bath at 40° C. for 1 h.

[0146] After the reaction, water was added to the product system, and the mixture was extracted with ethyl acetate. The organic phase was collected and the crude product was subjected to column chromatography (eluent: petroleum ether:ethyl acetate = 5:1 (mass ratio)) to obtain 203.2 g of product intermediate 1 with a yield of 60.86%.

[0147] Step 2: Synthesis of Intermediate 2

[0148] 203.2 g of intermediate 1 was dissolved in 2 L of toluene, and then 4.51 g of an aqueous solution of p-toluenesulfonic acid was added, heated to 100° C.-140° C. (e.g., 120° C.) and stirred for 2 hours, and the heating was stopped. After the product system was cooled to room temperature, water was added thereto, and the liquid was separated. The organic phase was washed with water three times, and the toluene was evaporated to dryness. The product was separated by column chromatography to obtain the product intermediate 2, and the yield was 176.3 g, and the yield was 93.14%.

[0149] Step 3: Synthesis of Intermediate 3

[0150] 30g of intermediate 2, 31.86g of biboric acid pinacol ester and 30.78g of potassium acetate were added to a flask, and 300mL of toluene was added for stirring. Then catalyst PdCl2 (dppf) was added to the flask, and heated to reflux for 12 hours after nitrogen replacement. After completion of the reaction, the product system was purified by column chromatography to obtain product intermediate 3, with an output of 25.4g and a yield of 70.16%.

[0151] Step 4: Synthesis of Intermediate 4

[0152] 14.85g of intermediate 3, 8.49g of 1-chloroisoquinoline, 15g of potassium carbonate, 50mg of palladium acetate (Pd(AcO)2), 0.2g of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl (X-PHOS), 75mL of water, 75mL of ethanol, and 150mL of toluene are added to a flask, heated to 100°C-140°C (e.g. 120°C) under nitrogen protection and refluxed for 18h, and then the heating is stopped. The organic phase is extracted and collected from the product system, and the organic phase is mixed with silica gel, and separated by column chromatography (eluent is dichloromethane) to obtain a light yellow product intermediate 4, with a yield of 12.8g and a yield of 85.84%. Among them, palladium acetate and X-PHOS are catalysts, and water, ethanol and toluene are combined to form a solvent.

[0153] Step 5: Synthesis of Intermediate 5

[0154] 1.95 g of intermediate 4, 1 g of iridium trichloride trihydrate, and 60 mL of ethylene glycol ether solvent were added to a single-mouth bottle, heated to 115°C under nitrogen protection, and stirred for 24 hours. Heating was stopped, and the product system was directly filtered. The filter cake was washed three times with ethanol, water, and tertiary methyl ether in sequence to obtain a dark red solid, which was intermediate 5.

[0155] Step 6: Synthesis of Iridium Complex RD5

[0156] The intermediate 5 (2.84 mmol), 3.3 g 3,7-diethyl-4,6-nonanedione, and 0.54 g potassium carbonate were added to a single-necked flask, dissolved with 55 mL of dichloromethane, stirred at room temperature for 24 hours, and then stopped stirring. The product system was separated by column chromatography (eluents were dichloromethane and n-hexane) to obtain 0.5 g of iridium complex RD5, with a yield of 19%.

[0157] The iridium complex RD5 was subjected to elemental testing, and the test parameters are as follows:

[0158] 1H-NMR(400MHz,Chloroform-d)δ8.98(m,2H),8.39(d,J=6.3Hz,2H),8.17(d,J= 8.4Hz,2H),7.89(m,2H),7.70(m,4H),7.38(t,J=6.8Hz,2H),6.98(m,2H),6.56( m,2H),5.83(s,2H),5.07(s,1H),4.14(m,3H),3.70(m,3H),2.16(s,3H),1.75(m ,2H),1.44-1.31(m,2H),1.31-0,88(m,9H),0.57(t,J=7.4Hz,6H),0.20(m,6H). The hydrogen nuclear magnetic spectrum of the iridium complex RD5 is as follows Figure 2 As shown, according to the above test parameters and Figure 2 It can be seen that the chemical structural formula of the iridium complex RD5 is consistent with its chemical structural formula.

[0159] The maximum emission wavelength of the iridium complex RD5 in toluene is 650 nm, which is deep red light and exhibits better color saturation.

[0160] The thermal stability of the iridium complex RD5 was tested, and the thermal decomposition temperature (0.5% weight loss) of the iridium complex RD5 was measured by thermogravimetric analysis (TGA). The results showed that the thermal decomposition temperature was 328.9°C, which indicates that the iridium complex RD5 has excellent thermal stability (i.e., longer service life).

[0161] For comparison, the thermal decomposition temperature (0.5% weight loss) of the iridium complex di(1-phenylisoquinoline)(acetylacetonate)iridium (referred to as Ir(pig)2acac) and the iridium complex Ir-1 was also tested in the same test method. See Table 1 below for details, wherein the chemical structure of the iridium complex Ir(pig)2acac is shown below:

[0162]

[0163] The chemical structure of compound Ir-1 is shown below:

[0164]

[0165] Table 1 Thermal stability parameters

[0166] Iridium complexes Thermal decomposition temperature / ℃ RD5 328.9 Ir(pig)2acac 285.1 Ir-1 310.6

[0167] It can be seen that the iridium complex RD5 prepared in Example 1 has a higher thermal decomposition temperature, which makes it exhibit excellent thermal stability.

[0168] Example 2

[0169] In this embodiment 2, based on the iridium complex RD5 prepared in embodiment 1, an organic electroluminescent device is prepared, which includes the following layers stacked in sequence: glass / anode / hole injection layer (MoO3, thickness 3nm) / hole transport layer (thickness 30nm) / electron blocking layer (TATC, thickness 10nm) / light-emitting layer (thickness 25nm) / electron transport layer (TPBI, thickness 40nm) / electron injection layer (LiF, thickness 1nm) / cathode (Al, thickness 100nm).

[0170] The raw materials for preparing the light-emitting layer include a main light-emitting material and an iridium complex RD5 in a mass ratio of 95:5.

[0171] The preparation method of the organic electroluminescent device is as follows:

[0172] (1) A transparent conductive ITO glass substrate with an anode (China Southern Glass Group Co., Ltd.) was ultrasonically treated in a commercial cleaning agent, rinsed in deionized water, and then washed in ethanol, acetone and deionized water in sequence, baked in a clean environment to completely remove moisture, cleaned with ultraviolet photosynthetic ozone, and then treated with oxygen plasma for 30 seconds.

[0173] (2) The transparent conductive ITO glass substrate with the anode 120 after the above pretreatment is placed in a vacuum chamber, evacuated, and molybdenum oxide (3 nm) is evaporated on the surface of the ITO anode as a hole injection layer at a deposition rate of 0.1 nm / s.

[0174] (3) The compound N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) was evaporated on the surface of the hole injection layer to form a 30 nm thick hole transport layer at a deposition rate of 0.1 nm / s.

[0175] (4) 4,4',4"-tri(carbazole-9-yl)triphenylamine (TCTA) was evaporated on the surface of the hole transport layer to form an electron blocking layer with a thickness of 10 nm. The evaporation rate was 0.1 nm / s.

[0176] (5) A 25 nm thick light-emitting layer is evaporated on the surface of the hole blocking layer, wherein 95% by weight of 4,4-di(9-carbazole)biphenyl (CBP) is used as the main light-emitting material and 5% by weight of iridium complex RD5 is used as the doping guest material. The evaporation rate is 0.1 nm / s.

[0177] (6) A 40 nm thick 1,3,5-tri(1-phenyl-1H-benzimidazol-2-yl)benzene (TPBI) was evaporated on the surface of the light-emitting layer as an electron transport layer at a deposition rate of 0.1 nm / s.

[0178] (7) LiF with a thickness of 1 nm was evaporated on the surface of the electron transport layer as the electron injection layer, and aluminum with a thickness of 100 nm was used as the cathode.

[0179] Comparative Example 1

[0180] An organic electroluminescent device is provided, which is different from Example 2 only in that an iridium complex Ir(piq)2acac is used instead of the iridium complex RD5.

[0181] Comparative Example 2

[0182] An organic electroluminescent device is provided, which is different from Example 2 only in that the iridium complex Ir-1 is used instead of the iridium complex RD5.

[0183] For the organic electroluminescent devices provided in Example 2, Comparative Example 1 and Comparative Example 2, a PR-655 Photo Research spectral scanning colorimeter was used to measure the organic electroluminescent devices at 10 mA / cm 2 The working voltage, external quantum efficiency and emission wavelength under the test results are shown in Table 2:

[0184] Table 2

[0185]

[0186] As can be seen from Table 2, based on the use of the iridium complex RD5 provided in the embodiment of the present invention, in which a tetrahydropyran ring is introduced, the luminescent wavelength of the organic electroluminescent device provided in Example 2 can reach 644nm, which belongs to the deep red light region. Moreover, at the same current density, the operating voltage of Example 2 is lower, and the improvement rate of its external quantum efficiency exceeds 15% compared with Comparative Example 2.

[0187] The above description is only for the purpose of facilitating those skilled in the art to understand the technical solution of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An iridium complex, characterized in that The iridium complex is used to emit red light, and the emission wavelength is greater than 630nm. The chemical structural formula of the iridium complex is as follows: ； Wherein, Ring A is an aromatic ring or heteroaromatic ring having 6 to 30 carbon atoms; R 11 ~R 13 Each is independently hydrogen, deuterium, fluorine, C1~C20 alkyl, C3~C20 cycloalkyl, C6~C30 aryl, or C3~C30 heteroaryl; R1-R6 are all hydrogen, at least one of (R7)n is an oxygen-containing heterocycle, wherein n≥1, the oxygen-containing heterocycle comprises at least four carbon atoms, and those of (R7)n that are not oxygen-containing heterocycles are each independently hydrogen, deuterium, fluorine, cyano, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C30 aryl, or C3-C30 heteroaryl; The oxygen-containing heterocycle is a substituted or unsubstituted pyranyl, a substituted or unsubstituted dihydropyranyl, a substituted or unsubstituted furanyl, or a substituted or unsubstituted dihydrofuranyl, wherein the substituent in the oxygen-containing heterocycle is a C1-C3 saturated alkyl, a halogen, or a C3-C30 saturated or unsaturated phenyl, cycloalkyl or heterocyclic group.

2. A method for preparing an iridium complex, characterized in that: The iridium complex is as shown in claim 1; The preparation method of the iridium complex comprises: providing a first ligand compound and a second ligand compound; The first ligand compound, the second ligand compound and potassium carbonate or sodium carbonate are stirred and reacted in a solvent to obtain the iridium complex; Wherein, the chemical structural formula of the first ligand compound is as follows: The chemical structural formula of the second ligand compound is as follows: 。 3. An organic light-emitting device, characterized in that: The organic light-emitting device comprises a light-emitting layer, the raw materials for preparing the light-emitting layer comprise the iridium complex according to claim 1 and a main light-emitting material, and the iridium complex serves as an emission dopant in the light-emitting layer; The mass ratio of the main luminescent material to the iridium complex is 15-25:1.

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