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

Abstract

The invention belongs to the field of organic photoelectric materials, and discloses an organic iridium metal compound, a preparation method and an organic electroluminescent device containing the organic iridium metal compound. According to the organic iridium metal compound provided by the invention, functional groups such as benzene, biphenyl and the like are introduced to a dibenzofuran ring main body, and an electron withdrawing group such as cyano or methyl and the like is added to a benzene ring, so that the molecular configuration is changed, a conjugated system is enlarged, and the electrochemical characteristics of the 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 invention belongs to the field of organic photoelectric materials, and in particular relates to an organic iridium metal compound, a preparation method and an organic electroluminescent device containing the same. Background Art

[0002] As a new generation of display technology, organic electroluminescent materials (OLEDs) have the advantages of ultra-thinness, self-luminescence, wide viewing angle, fast response, high luminous efficiency, good temperature adaptability, simple production process, low driving voltage and low energy consumption. They have been widely used in industries such as flat panel displays, flexible displays, solid-state lighting and automotive displays.

[0003] Since the first report of high-efficiency organic light-emitting diodes, the industry has been committed to studying how to improve device efficiency and stability. Phosphorescent materials have strong spin-orbit coupling, and excitons are formed by the recombination of electrons and holes injected from each electrode. Singlet excitons emit fluorescence, and triplet excitons emit phosphorescence. Emitting singlet excitons have a 25% formation probability, while phosphorescent triplet excitons have a 75% formation probability. Therefore, compared with singlet excitons, triplet excitons provide greater luminescence efficiency. Among such luminescent materials, organic phosphorescent materials have greater luminescence efficiency than fluorescent materials, and theoretically can achieve 100% luminescence efficiency.

[0004] Because the luminous efficiency of phosphorescent materials is significantly higher than that of fluorescent materials, many scientific research institutions are increasing their research and development efforts on phosphorescent materials, trying to accelerate industrial development through phosphorescent materials. However, in the prior art, some phosphorescent materials used in organic light-emitting devices have low efficiency and short life. Therefore, how to provide an organic electroluminescent material with long life, high efficiency and low driving voltage is a problem that technicians in this field need to solve urgently. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention discloses an organic iridium metal compound, a preparation method and an organic electroluminescent device containing the same. After the organic iridium metal compound provided by the present invention is used in an organic electroluminescent device, the starting voltage of the device is reduced and the luminous efficiency and life of the device are improved.

[0006] In order to achieve the above object, the first object of the present invention is to provide an organic iridium metal compound. The following technical scheme is adopted:

[0007] An organic iridium metal compound having a structure shown in general formula I:

[0008]

[0009] Among them, R1 to R 19The same or different from each other, are independently selected from -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, silicon, germanium, substituted or unsubstituted C2-C 10 Alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 20 Aryl, substituted or unsubstituted 4- to 8-membered heterocyclic group.

[0010] Furthermore, the hydrogen atoms in the above groups may be substituted by deuterium or not.

[0011] It should be noted that the above term "substituted or unsubstituted C2-C 10 alkyl", "substituted or unsubstituted C3-C8 cycloalkyl", "substituted or unsubstituted C6-C 20 The number of carbon atoms in the alkyl, cycloalkyl, aryl and heteroaryl groups in the "aryl group" and "substituted or unsubstituted 4- to 8-membered heterocyclic group" refers to the number of carbon atoms constituting the unsubstituted aryl group or the total number of heteroatoms and carbon atoms constituting the heteroaryl group, without taking into account the number of carbon atoms in the substituent.

[0012] Furthermore, the ligand La is selected from one of the following structures LA-1 to LA-96:

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[0017] In the present invention, the organic iridium metal compound is selected from any one of the following structures:

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[0080] Only some specific structural forms are listed above, but this series of organic iridium metal compounds is not limited to the above molecular structures. Other specific molecular structures can be obtained by simple changes of some simple groups and their substituted groups and substitution positions, which will not be described one by one here.

[0081] The 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 preparation method known to those skilled in the art.

[0082] Reference to common knowledge is as follows:

[0083] "Transition Metal Organic Chemistry" (Original Sixth Edition), Robert H. Crabtree, Publisher: Shanghai East China University of Science and Technology Press, Publication Date: 2017-09-00, ISBN: 978-7-5628-5111-0, page 388.

[0084] "Organic Chemistry and Optoelectronic Materials Experimental Tutorial", Chen Runfeng, Publisher: Southeast University Press, Publication Date: 2019-11-00, ISBN: 9787564184230, Page 174.

[0085] Alternatively, the following reaction process is preferred for preparation, and the specific synthetic route is as follows:

[0086] In the formula, R1 to R 19 As defined in the above chemical formula I

[0087] Step 1: Add raw material LA, iridium trichloride trihydrate, ethylene glycol ethyl ether and water under nitrogen, react at 120°C for 48 hours, filter, rinse with ethanol and petroleum ether, and dry to obtain intermediate L-A1;

[0088] Step 2: Add intermediate L-A1, silver trifluoromethanesulfonate, isopropanol and dichloromethane under nitrogen, react at 25°C for 48 hours, pass through a silica gel funnel, rinse with dichloromethane until there is no product, combine the organic phases and spin dry to obtain intermediate L-A2;

[0089] Step 3: Add intermediate L-A2, LB and ethanol under nitrogen conditions, react at 90°C for 48 hours, filter and obtain product L by column chromatography.

[0090] The third object of the present invention is to provide use of the above-mentioned organic iridium metal compound in an organic electroluminescent device.

[0091] The present invention provides an organic electroluminescent device, comprising the organic iridium metal compound as described above.

[0092] The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode, wherein the organic layer comprises the organic iridium metal compound of the present invention; the organic iridium metal compound is in a single form or mixed with other substances and exists in the organic layer.

[0093] The organic layer at least includes 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 them.

[0094] The organic electroluminescent device comprises at least one functional layer, namely the organic iridium metal compound of the present invention.

[0095] The organic electroluminescent device comprises a light-emitting layer, and the light-emitting layer contains the organic iridium metal compound of the present invention.

[0096] The light-emitting layer of the organic electroluminescent device includes a main material and a doping material, wherein the doping material is the organic iridium metal compound described in the present invention, and the mixing mass ratio of the main material to the doping 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.

[0097] 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.

[0098] Compared with the prior art, the present invention has the following beneficial effects:

[0099] The invention provides an organic iridium metal compound, which introduces some functional groups such as benzene and biphenyl on the main body of a dibenzofuran ring, and adds some electron-withdrawing groups such as cyano or methyl on the benzene ring to change the molecular configuration, increase the conjugated system, and adjust the electrochemical properties of the compound, so that the obtained organic compound can reduce the starting voltage of an organic electroluminescent device after being used in the device, and improve the luminous efficiency and life of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0100] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0101] Figure 1 It is the hydrogen nuclear magnetic resonance spectrum of compound L-336. DETAILED DESCRIPTION

[0102] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention and the related drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0103] The invention specifically discloses an organic iridium metal compound and an organic electroluminescent device containing the organic iridium metal compound.

[0104] The features and performance of the present invention will be further described in detail below with reference to the embodiments.

[0105] Example 1 Preparation of organometallic compound L-336

[0106] The specific operation and process route are as follows:

[0107]

[0108] The first step C-001 synthesis:

[0109] Under nitrogen conditions, A-001 (CAS: 1369793-66-7, 276 mmol), B-001 (CAS: 252670-79-4, 276 mmol), tetrakis(triphenylphosphine)palladium (27 mmol), potassium carbonate (828 mmol), tetrahydrofuran (1 L), water (500 mL) were weighed, incubated at 90°C for 24 h, separated, and spin-dried by column chromatography to obtain intermediate C-001 (88 g, yield 81.2%, HPLC: 99.2%).

[0110]

[0111] Step 2 D-001 synthesis:

[0112] Under nitrogen conditions, weigh C-001 (127 mmol) and dissolve it in 500 mL of dichloromethane. The temperature was cooled to 0°C under nitrogen protection, and boron tribromide (140 mmol) was slowly added dropwise. After the addition was completed, the temperature was gradually raised to 25°C and stirred for 24 h. The TLC spot plate showed that C-001 completely disappeared. The reaction solution was poured into 1200 mL of water, the layers were separated, the aqueous phase was extracted twice, and the organic phases were combined for column chromatography to obtain the product (41.7 g, yield 87%, HPLC>99%).

[0113]

[0114] Step 3 E-001 synthesis:

[0115] Under nitrogen, weigh D-001 (106 mmol), tetrabutylammonium bromide (21 mmol), lithium hydroxide (952 mmol), sodium dithionite (21 mmol) and add to 400 mL of N-methylpyrrolidone, then heat to 120°C and stir for 24 h. TLC detects the disappearance of D-001, pour the reaction solution into 1200 mL of water, stir for 0.5 h, and filter to obtain a solid. The solid is dissolved by column chromatography to obtain the product (22 g, yield 70%, HPLC>99.5%).

[0116]

[0117] Step 4 G-001 synthesis:

[0118] Under nitrogen conditions, take E-001 (168 mmol), 2-pyridineboronic acid (CAS: 197958-29-5, 185 mmol), tetrakis(triphenylphosphine)palladium (8.4 mmol), potassium carbonate (804 mmol), tetrahydrofuran (1 L) and water (500 mL), react at 90 ° C for 24 hours, TLC detection E-001 disappears, separate the liquids, spin dry column chromatography to obtain G-001 (43 g, yield 87%, HPLC: 99.2%).

[0119]

[0120] Step 5: H-001 synthesis:

[0121] G-001 (169 mmol), chloroform 1 L, acetic acid 300 mL were weighed under nitrogen and stirred for 5 minutes. NBS (254 mmol) was added at 25°C and stirred for 24 hours. G-001 disappeared after TLC detection. Saturated brine (500 mL) was added, the liquids were separated, the organic phases were combined, and H-001 (25.3 g, yield 40%, HPLC>99.2%) was obtained by column chromatography.

[0122]

[0123] Step 6: J-001 synthesis:

[0124] Under nitrogen, weigh H-001 (53 mmol), phenylboronic acid (CAS: 98-80-6, 64 mmol), tetrakis(triphenylphosphine)palladium (1 mmol), potassium carbonate (160 mmol), toluene (300 mL), ethanol (150 mL), and water (150 mL), react at 120°C for 10 h, detect the disappearance of H-001 by TLC, add 200 mL of water, separate the liquids, combine the organic phases, and spin dry the product by column chromatography (15.8 g, yield 80%, HPLC: 99.5%)

[0125]

[0126] Step 7: M-001 synthesis:

[0127] Under nitrogen, weigh K-001 (322 mmol), iridium trichloride trihydrate (CAS: 13569-57-8, 107 mmol), 320 mL of ethylene glycol ethyl ether, and 40 mL of water. React at 120° C. for 48 h, and filter to obtain the product (53 g, yield 92%).

[0128]

[0129] Step 8: Synthesis of N-001:

[0130] Under nitrogen, weigh M-001 (47 mmol), silver trifluoromethanesulfonate (117 mmol), 220 ml of isopropanol, and 1 L of dichloromethane. React at 25°C for 48 h and pass through a silica gel funnel to obtain the product (70 g, yield 98%).

[0131]

[0132] Step 9: L-336 synthesis:

[0133] Under nitrogen, N-001 (39 mmol), J-001 (156 mmol), and anhydrous ethanol (300 mL) were weighed, reacted at 90°C for 48 h, filtered, and the product was obtained by solid column chromatography (17 g, yield 50%, HPLC: 99.3%).

[0134] Mass spectrum: 871.55

[0135] NMR: (400MHz, Chloroform-d) δ8.87(dd,1H),8.64(dd,2H),8.10(ddd,3H),8.04(d,1H),7.88(d 1H),7.84-7.76(m,3H),7.74-7.65(m,3H),7.60(d,1H),7.51-7.48(m,3H),7.47(d,1H),7.46(d,2H),7.45( t,2H),7.43(d,1H),7.36(t,1H),7.36-7.34(m,1H),7.33(t,1H),7.25(ddd,2H),7.19(td,2H),7.10(s,1H).

[0136] The NMR spectrum of compound L-336 is as follows Figure 1 shown.

[0137] The synthesis methods of other organometallic iridium complexes L-31, L-85, L-93, L-124, L-135, L-193, L-302, L-303, L-311, L-312, L-320, L-321, L-322, L-400, L-401, L-433, L-434, L-459, L-460, L673, L901, and L-973 are the same as those in the above embodiments and are not described in detail here. The molecular formula and mass spectrum of the synthesized organometallic iridium complexes are shown in Table 1 below.

[0138] Table 1

[0139]

[0140]

[0141] Device Example 1: Preparation of an organic electroluminescent device using an organometallic compound of formula L-336

[0142] The coating thickness is The ITO glass substrate was washed twice in distilled water and ultrasonically washed for 30 minutes. After the distilled water washing, it was ultrasonically washed in isopropyl alcohol, acetone, methanol and other solvents in sequence, dried, and transferred to the plasma cleaning machine. The above substrate was washed for 5 minutes and sent to the evaporation machine. First, the ITO (anode) was evaporated with a thickness of 4,4',4"-tri[2-naphthylphenylamino]triphenylamine ("2-TNATA") is used as a hole injection layer, and then a layer with a thickness of 1000 nm is deposited on the hole injection layer. N,N'-diphenyl-N,N'-(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) is used as the hole transport layer, followed by evaporation with a thickness of The main material 4,4'-N,N'-biphenyl dicarbazole ("CBP") and the dopant material compound formula L-33690:10 weight ratio of the light-emitting layer, and then evaporated on the light-emitting layer with a thickness of ALq3 is used as the electron transport layer, and then the thickness of the electron transport layer is evaporated on the electron transport layer. The electron injection layer material Liq is finally deposited on the electron injection layer with a thickness of By adding aluminum as the cathode material, an organic electroluminescent device can be obtained.

[0143] The performance luminescence characteristics of the obtained device were tested using a KEITHLEY 2400 source measurement unit and a CS-1000 spectroradiometer to evaluate the driving voltage, lifespan, and luminous efficiency.

[0144] Device Example 2-23:

[0145] Referring to the method of the above-mentioned device embodiment L-336, the only difference is that the doping material L-336 is replaced by L-31, L-85, L-93, L-124, L-135, L-193, L-302, L-303, L-311, L-312, L-320, L-321, L-322, L-400, L-401, L-433, L-434, L-459, L-460, L-673, and L-901.

[0146] Device Comparison Example 1:

[0147] An organic electroluminescent device was prepared in the same manner as in device example L-336. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0148]

[0149] Device Comparison Example 2:

[0150] An organic electroluminescent device was prepared in the same manner as in device example L-336. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0151]

[0152] Device comparison example 3:

[0153] An organic electroluminescent device was prepared in the same manner as in device example L-336. The structure of the green light-emitting doping compound in the luminescent layer was as follows:

[0154]

[0155] The driving voltage, luminous efficiency and life of the organic electroluminescent devices obtained from the above device embodiments and device comparative examples were characterized at a brightness of 1000 (nits). The test results are shown in Table 2 below.

[0156] Table 2

[0157]

[0158] From the comparison of the device data in Table 2, it can be seen that adding a benzene ring substituted with phenyl to dibenzofuran increases its conjugated system, and by changing its spatial structure, the driving voltage is significantly reduced, and the luminous efficiency and life are significantly improved. From other comparative examples, it can also be seen that adding an electron-withdrawing group to the benzofuran ring makes its structure more stable, thereby greatly improving the service life of the device.

[0159] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An organic iridium metal compound, characterized in that The structure of the organic iridium metal compound is shown in Formula I: Among them, R1 to R 19 The same or different from each other, are independently selected from -H, -D, -T, -F, -CN, -CH3, -CD3, -CT3, -CF3, -CH2F, -CHF2, silicon, germanium, substituted or unsubstituted C2-C 10 Alkyl, substituted or unsubstituted C3-C8 cycloalkyl, substituted or unsubstituted C6-C 20 Aryl, substituted or unsubstituted 4- to 8-membered heterocyclic group.

2. The organoiridium metal compound according to claim 1, characterized in that The hydrogen atoms in the groups may be substituted with deuterium or not.

3. The organoiridium metal compound according to claim 1, characterized in that The ligand La is selected from one of the following structures LA-1 to LA-96:

4. The organoiridium metal compound according to claim 1, characterized in that The organic iridium metal compound is selected from any one of the following structures:

5. A method for preparing an organic iridium metal compound as claimed in claim 1, characterized in that: The method specifically comprises the following steps: Step 1: Add raw material LA, iridium trichloride trihydrate, ethylene glycol ethyl ether and water under nitrogen, react at 120°C for 48 hours, filter, rinse with ethanol and petroleum ether, and dry to obtain intermediate L-A1; Step 2: Add intermediate L-A1, silver trifluoromethanesulfonate, isopropanol and dichloromethane under nitrogen, react at 25°C for 48 hours, pass through a silica gel funnel, rinse with dichloromethane until there is no product, combine the organic phases and spin dry to obtain intermediate L-A2; Step 3: Add intermediate L-A2, LB and ethanol under nitrogen, react at 90°C for 48 hours, filter and obtain product L by column chromatography; The specific synthetic route is as follows: In the formula, R1 to R 19 The definition given in chemical formula I as claimed in claim 1.

6. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the organic iridium metal compound as claimed in claim 1 .

7. The organic electroluminescent device according to claim 6, 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 iridium metal compound.

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

9. The organic electroluminescent device according to claim 8, 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 iridium metal compound, 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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