Organic metal iridium complex, preparation method and organic electroluminescent device containing organic metal iridium complex

Abstract

The invention belongs to the technical field of organic electroluminescence, and discloses an organic metal iridium complex, a preparation method and an organic electroluminescence device containing the organic metal iridium complex. The structure of the organic metal iridium complex is as shown in formula I. According to the organic metal iridium complex provided by the invention, a nitrogen-containing heterocyclic functional group is introduced to a pyridine ring, and meanwhile, some electron withdrawing groups such as cyano or methyl and the like are added, so that the molecular configuration is changed, a conjugated system is enlarged, and the electrochemical characteristics of a compound are adjusted; after the obtained organic compound is applied to the organic electroluminescent device, the starting voltage of the device is reduced, the luminous efficiency of the device is improved, and the service life of the device is prolonged.

Description

Technical Field

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

[0002] Organic light emitting diodes (OLEDs) are a type of device with a sandwich-like structure, consisting of positive and negative electrode film layers and an organic functional material layer sandwiched between the electrode film layers. When voltage is applied to the electrodes of an OLED device, positive charges are injected from the positive electrode and negative charges from the negative electrode. Under the 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 OLED devices such as high brightness, fast response, wide viewing angle, simple process, and flexibility, they have attracted much attention in the fields of new display technologies and new lighting technologies. Currently, this technology has been widely used in display panels for new lighting fixtures, smart phones, tablet computers, and other products. It will also be further expanded to large-size display products such as televisions. It is a new display technology that is developing rapidly and has high technical requirements. The research on high-efficiency phosphorescent organic electroluminescent devices has provided an important driving force for the development of the flat panel and portable display industries.

[0003] However, organic electroluminescent devices (OLEDs) based on phosphorescent materials suffer from high driving voltages, low luminous efficiency, and short lifespans, severely limiting their application. Therefore, developing high-performance phosphorescent materials that combine high efficiency, long lifespan, and low voltage in OLEDs is a pressing technical challenge facing researchers in this field. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides an organometallic iridium complex, a preparation method, and an organic electroluminescent device containing the same. The organometallic iridium complex provided by the present invention, when used in an organic electroluminescent device, reduces the device's startup voltage and improves the device's luminous efficiency and lifespan.

[0005] In order to achieve the above objectives, the first object of the present invention is to provide an organometallic iridium complex. The following technical solution is adopted:

[0006] An organometallic iridium complex having a structure shown in general formula I:

[0007]

[0008] in,

[0009] X is O, S, Se, NR′, Si R′R ″ 、Ge R′R ″, CR′R ″ Any one of R′, R ″ Selected from -F, -CN, -CD3, methyl, ethyl, tert-butyl, isopropyl;

[0010] Ring H is a 3-6 membered heterocyclic ring containing N, wherein N is a substituted attachment site, S1 represents a substituent attached to any carbon of Ring H, and S1 is independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trimethylsilyl, trimethylgermanium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C20 aryl, and substituted or unsubstituted 4-8 membered heterocyclyl;

[0011] R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 and S2 are each independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trimethylsilyl, trimethylgermanium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-8 membered heterocyclic group; wherein R 14 With R 13 、R 13 With R 12 、R 12 With R 11 A ring structure can be formed between them.

[0012] Furthermore, R 14 With R 13 、R 13 With R 12 、R 12 With R 11 The ring structures formed therebetween are preferably the following:

[0013]

[0014]

[0015] Among them, R D represents zero substitution, monosubstitution, or polysubstitution (at least two up to the maximum allowed substitution) on its associated ring; and each R D independently hydrogen or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, cyano, aryl, heteroaryl, trimethylsilyl, trimethylgermanium;

[0016] Y is O, S, Se, NR′, Si R′R ″ 、Ge R′R″ , CR′R ″ Any one of R′, R ″ Selected from -F, -CN, -CD3, methyl, ethyl, tert-butyl, isopropyl.

[0017] Furthermore, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 and S1 and S2 are each independently selected from hydrogen, deuterium, tritium, fluorine, cyano, -CH3, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, phenyl, -CD3, and any one of the groups represented by the following structural formula:

[0018]

[0019] Among them, * represents the replacement position.

[0020] Furthermore, ligand A is selected from any one of LA-1 to LA-100 represented by the following structural formula:

[0021]

[0022]

[0023]

[0024]

[0025] In the present invention, the organometallic iridium complex is selected from any one of the following structures:

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

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[0044]

[0045]

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[0048]

[0049]

[0050]

[0051]

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[0053]

[0054]

[0055]

[0056]

[0057]

[0058]

[0059] Only some specific structural forms are listed above, but this series of organometallic iridium complexes are not limited to the above molecular structures. Other specific molecular structures can be obtained by simple transformation of some simple groups and their substituted groups and substitution positions, which will not be listed here one by one.

[0060] A second object of the present invention is to provide a method for preparing the above-mentioned organometallic iridium complex. The organometallic iridium complex of the present invention can be prepared by a synthetic method known to those skilled in the art. Alternatively, the following reaction scheme is preferably used for preparation. The specific synthetic route is as follows:

[0061]

[0062] The specific operations are as follows:

[0063] Step 1: Under an inert gas atmosphere, react intermediate A (1.0-1.1 eq), raw material B (1 eq), tetrakistriphenylphosphine palladium (1%-3% eq), potassium carbonate (2-5 eq), tetrahydrofuran, and water at 80-95° C. for 18-30 h; separate the liquids, and spin dry the mixture for column chromatography to obtain intermediate LB.

[0064] Step 2: Under an inert gas atmosphere, the raw material LA and iridium trichloride trihydrate are mixed and reacted at 100-120°C for 40-55 hours to form intermediate L-A1. Specifically, the raw material LA, iridium trichloride trihydrate, an alcohol ether solvent (e.g., ethylene glycol ethyl ether), and water are added under nitrogen, reacted at 100-120°C for 40-55 hours, filtered, rinsed with ethanol and petroleum ether, and dried to obtain intermediate L-A1.

[0065] Step 3: Under an inert gas atmosphere, the intermediate L-A1 and silver trifluoromethanesulfonate are mixed and reacted at 20-35°C for 40-55 hours to form intermediate L-A2. Specifically, intermediate L-A1, silver trifluoromethanesulfonate, an alcohol solvent (e.g., isopropyl alcohol), and a chloroalkane (e.g., dichloromethane) are added under nitrogen, reacted at 20-35°C for 40-55 hours, then passed through a silica gel funnel and rinsed with dichloromethane until no product is present. The combined organic phases are then spin-dried to obtain intermediate L-A2.

[0066] Step 4: Under an inert gas atmosphere, the intermediate L-A2 and LB are mixed and reacted at 80-100°C for 40-55 hours. Specifically, under nitrogen conditions, the intermediate L-A2, LB, and an alcohol solvent (e.g., ethanol) are added and reacted at 80-100°C for 40-55 hours, followed by filtration and column chromatography to obtain product L.

[0067] The third object of the present invention is to provide the use of the above-mentioned organometallic iridium complex in an organic electroluminescent device.

[0068] The present invention provides an organic electroluminescent device comprising the above-mentioned organometallic iridium complex.

[0069] The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein the organic layer contains the organometallic iridium complex of the present invention; the organometallic iridium complex is in a single form or mixed with other substances and exists in the organic layer.

[0070] The organic layer includes at least a hole injection layer, a hole transport layer, a layer having both hole injection and hole transport skills, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer and a layer having both electron transport and electron injection skills, or a combination of at least two of the above.

[0071] The organic electroluminescent device comprises at least one functional layer, namely the organic metal iridium complex of the present invention.

[0072] The organic electroluminescent device comprises a light-emitting layer, and the light-emitting layer contains the organic metal iridium complex of the present invention.

[0073] The light-emitting layer of the organic electroluminescent device includes a host material and a dopant material, wherein the dopant material is the organic metal iridium complex described in the present invention, and the mixing mass ratio of the host material to the dopant material is 90:10 to 99.5:0.5, for example, 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2 or 99:1, etc.

[0074] The device of the present invention can be used in organic light-emitting devices, organic solar cells, electronic paper, organic photoreceptors or organic thin film transistors.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] 1) The present invention provides an organometallic iridium complex. By adding a nitrogen-containing heterocycle to the pyridine ring, the rigid structure suppresses molecular aggregation, while the charge-deficient nitrogen atoms can enhance the host-guest energy transfer efficiency, thereby improving the overall performance of the device.

[0077] 2) When the organometallic iridium complex of the present invention is applied to an organic electroluminescent device, its driving voltage is significantly reduced, and its lifespan and luminous efficiency are also correspondingly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0079] Figure 1 is the H NMR spectrum of compound L-8. DETAILED DESCRIPTION

[0080] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments of the present invention and the related drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0081] The present invention specifically discloses an organic metal iridium complex and an organic electroluminescent device containing the same.

[0082] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0083] Example 1

[0084] The present invention provides a method for preparing an organometallic iridium complex:

[0085]

[0086] Step 1: Under nitrogen, weigh intermediate A-8 (CAS No.: 912824-85-2 1.1 eq), raw material B-8 (CAS No.: 230618-42-5 1 eq), tetrakistriphenylphosphine palladium (3% eq), potassium carbonate (3 eq), tetrahydrofuran (20 eq), and water (10 eq) and react at 90°C for 24 h; separate the liquids, spin dry, and column chromatography to obtain intermediate C-8.

[0087]

[0088] Step 2: Under nitrogen conditions, weigh the raw material LA-8 (CAS No.: 1008-89-5 2.5eq), iridium trichloride (1eq), ethylene glycol ethyl ether (12eq), and water (4eq), react at 120°C for 48h, filter and rinse, and dry to obtain the intermediate L-A1-8.

[0089] Step 3: Under nitrogen conditions, weigh the raw material L-A1-8 (1 eq), silver trifluoromethanesulfonate (2 eq), dichloromethane (21 eq), and isopropanol (7 eq), react at 25°C for 48 h, pass through a silica gel funnel, and spin dry to obtain the intermediate L-A2-8.

[0090]

[0091] Step 4: Under nitrogen, weigh the raw materials L-A2-8 (1 eq), LB-8 (same as C-8, 2.5 eq), and ethanol (20 eq), react at 90°C for 48 h, and filter and column chromatography to obtain the final product L-8 (8.27 g, 65% yield).

[0092] HPLC purity: >99.3%. Mass spectrum: test value 814.35. Specifically, the NMR spectrum of the product L-8 can be found at Figure 1 .

[0093] The synthesis methods of other organometallic iridium complexes are the same as those in the above examples and are not described in detail here. The molecular formulas and mass spectra of the synthesized organometallic iridium complexes are shown in Table 1 below.

[0094] Table 1

[0095] Compound Molecular formula Mass spectrometry test value L-59 <![CDATA[C 45 H 37 D6IrN4O]]> 842.41 L-110 <![CDATA[C 45 H 31 D6IrN4O]]> 848.43 L-182 <![CDATA[C 48 H 31 D 12 IrN4O]]> 896.49 L-209 <![CDATA[C 49 H 49 IrN4OSi2]]> 958.44 L-260 <![CDATA[C 53 H 53 IrN4O]]> 954.49 L-332 <![CDATA[C 56 H 59 IrN4O]]> 996.55 L-368 <![CDATA[C 59 H 37 IrN4OD 12 ]]> 1034.59 L-410 <![CDATA[C 51 H 49 IrN4O]]> 926.48 L-411 <![CDATA[C 52 H 48 IrN5O]]> 951.48 L-413 <![CDATA[C 54 H 52 IrN5O]]> 979.47 L-414 <![CDATA[C 54 H 52 IrN5O]]> 979.46 L-461 <![CDATA[C 55 H 47 D1IrN4O]]> 992.57 L-534 <h2 style=";text-align:left;direction:ltr"><![CDATA[C <h2 style=";text-align:left;direction:ltr"> 69 <h2 style=";text-align:left;direction:ltr"> H<h2 style=";text-align:left;direction:ltr"> 43 <h2 style=";text-align:left;direction:ltr"> D<h2 style=";text-align:left;direction:ltr"> 18 <h2 style=";text-align:left;direction:ltr"> IrN4OSi]]><h2 style=";text-align:left;direction:ltr"> 1200.69 L-585 <![CDATA[C 51 H 37 D1IrN4O]]> 914.38 L-657 <![CDATA[C 59 H 53 IrN4O]]> 1026.50

[0096] Device Example 1

[0097] Device Example 1 provides an organic electroluminescent device. The light-emitting layer of the organic electroluminescent device is prepared by the product L-8 of Example 1 above. Specifically, the preparation method of the organic electroluminescent device is as follows:

[0098] The coating thickness is The ITO glass substrate was cleaned twice in distilled water and ultrasonically washed for 30 minutes. After the distilled water cleaning, it was ultrasonically cleaned in sequence with isopropyl alcohol, acetone, methanol and other solvents, and then dried. It was transferred to a plasma cleaning machine, washed for 5 minutes, and sent to a vapor deposition machine.

[0099] First, the thickness of the ITO (anode) is evaporated 4,4',4 ” -tris[2-naphthylphenylamino]triphenylamine ("2-TNATA") as the hole injection layer, and then evaporated on the hole injection layer to a thickness of The hole transport layer of N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) is used as the hole transport layer, and then the thickness of the hole transport layer is evaporated to The light-emitting layer is composed of a main material 4,4'-N,N'-biphenyldicarbazole ("CBP") and a dopant material (compound formula L-8 provided in Example 1) with a weight ratio of 90:10, and then a film with a thickness of 100 nm is deposited on the light-emitting layer. ALq3 is used as the electron transport layer, and then the thickness of the ALq3 layer is evaporated on the electron transport layer. The electron injection layer material Liq is finally evaporated on the electron injection layer with a thickness of By adding Al as cathode material, an organic electroluminescent device can be obtained.

[0100] Device Examples 2-16:

[0101] The organic electroluminescent devices provided in device examples 2-16 were prepared according to the preparation method provided in device example 1, with the only difference being that L-8 was changed to L-59, L-110, L-182, L-209, L-260, L-332, L-368, L-410, L-411, L-413, L-414, L-461, L-534, L-585, and L-657.

[0102] The driving voltage, luminous efficiency, and lifespan of the organic electroluminescent devices obtained from the above-mentioned device examples 1-16 and device comparative examples 1-8 were characterized at a brightness of 8000 (nits). The test results are shown in Table 2 below. (The test results are normalized to those of Comparative Example 1):

[0103]

[0104] Table 2 Test results

[0105]

[0106]

[0107] As shown in Table 2, by comparison with the comparative example, it can be seen that under the same single ligand situation, due to the addition of a nitrogen-containing heterocycle to the pyridine ring, molecular aggregation is suppressed through a rigid structure, the thermal decomposition temperature of the material is increased, and the device life is extended. The electron-withdrawing properties of the nitrogen-containing heterocycle can regulate intramolecular charge transfer (ICT) and reduce the exciton recombination energy loss. In addition, the charge-deficient nitrogen atom can enhance the host-guest energy transfer efficiency and improve the overall performance of the device.

[0108] By comparing Examples 10 to 12 with Comparative Example 8, it can be seen that although the driving voltage and lifespan do not change much, the strong π-π interaction caused by the reduction of the conjugated structure of the benzene ring leads to over-dense molecular stacking, forming a compact crystal or amorphous structure in a local ordered region, which avoids the excitons from being more easily quenched by energy transfer or charge recombination at high concentrations, thereby improving the luminescence efficiency.

[0109] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily 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 is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organometallic iridium complex, characterized in that The structure of the organometallic iridium complex is shown in Formula I: in, X is any one of O, S, Se, NR′, Si R′R″, Ge R′R″, CR′R″, and R′, R″ are selected from -F, -CN, -CD3, methyl, ethyl, tert-butyl, isopropyl; Ring H is a 3-6 membered heterocyclic ring containing N, wherein N is a substituted attachment site, S1 represents a substituent attached to any carbon of Ring H, and S1 is independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trimethylsilyl, trimethylgermanium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C20 aryl, and substituted or unsubstituted 4-8 membered heterocyclyl; R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 and S2 are each independently selected from any one of hydrogen, deuterium, tritium, halogen, cyano, trimethylsilyl, trimethylgermanium, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C20 aryl, substituted or unsubstituted 4-8 membered heterocyclic group; wherein R 14 With R 13 、R 13 With R 12 、R 12 With R 11 A ring structure can be formed between them.

2. The organometallic iridium complex according to claim 1, characterized in that R 14 With R 13 、R 13 With R 12 、R 12 With R 11 The ring structure formed therebetween is selected from the following: Among them, R D represents zero, mono or poly substitution on the relevant ring; and each R D independently hydrogen or a substituent selected from the group consisting of deuterium, fluorine, alkyl, cycloalkyl, heteroalkyl, cyano, aryl, heteroaryl, trimethylsilyl, trimethylgermanium; Y is any one of O, S, Se, NR′, Si R′R″, Ge R′R″, CR′R″, and R′, R″ are selected from -F, -CN, -CD3, methyl, ethyl, tert-butyl, and isopropyl.

3. The organometallic iridium complex according to claim 1, characterized in that R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 、R 11 、R 12 、R 13 、R 14 and S1 and S2 are each independently selected from hydrogen, deuterium, tritium, fluorine, cyano, -CH3, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, phenyl, -CD3, and any one of the groups represented by the following structural formula: Among them, * represents the replacement position.

4. The organometallic iridium complex according to claim 1, characterized in that Ligand A is selected from any one of LA-1 to LA-100 shown in the following structural formula:

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

6. A method for preparing an organometallic iridium complex as claimed in claim 1, characterized in that: The method specifically comprises the following steps: Step 1: Under an inert gas atmosphere, react raw materials A and B at 80-95°C for 18-30 hours; column chromatography to obtain intermediate LB; Step 2: Under an inert gas atmosphere, the raw material LA and iridium trichloride trihydrate are mixed at 100-120° C. and reacted for 40-55 hours to form the intermediate L-A1; Step 3: Under an inert gas atmosphere, the intermediate L-A1 and silver trifluoromethanesulfonate are mixed at 20-35° C. and reacted for 40-55 hours to form the intermediate L-A2; Step 4: Under an inert gas atmosphere, the intermediate L-A2 and LB were mixed at 80-100° C. for 40-55 hours, filtered, and subjected to column chromatography to obtain product L; The specific synthetic route is as follows: Where, R1 to R 14 , X, ring H, S1, S2 are as defined in Chemical Formula I as claimed in claim 1.

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the organometallic iridium complex according to claim 1 .

8. The organic electroluminescent device according to claim 7, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode; the organic layer contains the organic metal iridium complex.

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

10. The organic electroluminescent device according to claim 9, characterized in that: The light-emitting layer of the organic electroluminescent device comprises a main material and a doping material; the doping material is the organic metal iridium complex, and the mixing mass ratio of the main material to the doping material is 90:10 to 99.5:0.5.

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