CN110615816A - Phosphorescent material, preparation method thereof and organic electroluminescent device containing phosphorescent material - Google Patents

Abstract

The invention relates to a phosphorescent material and an organic electroluminescent device containing the same, and relates to the field of organic luminescent materials. The structural formula of the phosphorescent material is shown in chemical formula 1:

Description

A kind of phosphorescent material and its preparation method and organic electroluminescence comprising the material device

technical field

The invention relates to the field of organic luminescent materials, in particular to a phosphorescent material, a preparation method thereof and an organic electroluminescent device containing the material.

Background technique

An OLED display is a display made of organic light-emitting diodes. Due to its self-illumination, no need for backlight, high contrast, thin thickness, wide viewing angle, fast response, flexible panels, wide operating temperature range, simple structure and manufacturing process, etc., it is considered to be the next generation. Emerging application technologies of flat panel displays.

Since the discovery of phosphorescence, it has been pursued by everyone, because the luminous efficiency of phosphorescent materials is significantly higher than that of fluorescent materials, and it has greater advantages compared with traditional fluorescent materials as light-emitting devices, because it can simultaneously capture the light excited by the electric field. Singlet excitons and triplet excitons, so their internal quantum efficiency can break the theoretical limit of 25% based on fluorescent material devices, making 100% internal quantum efficiency possible. Therefore, many scientific research institutions are increasing the research and development of phosphorescent materials, trying to accelerate the development of industrialization through phosphorescent materials. However, due to the relatively high synthesis price of phosphorescent materials, the synthesis process requirements are relatively high, and the synthesis process is easy to pollute the environment, the purification requirements are relatively high, the life is short, and the efficiency is low.

Therefore, the above problems urgently need to be improved, and the use of phosphorescent materials needs to be solved and advanced.

Contents of the invention

In view of the above deficiencies in the prior art, the present invention provides a phosphorescent material, a preparation method thereof, and an organic electroluminescence device containing the material. The phosphorescent material provided by the invention adjusts the wavelength of the compound by selecting specific heterocyclic ligands for binding, and the obtained organometallic compound improves the luminous efficiency of the device and has a long service life after being used in an organic electroluminescent device.

In order to solve the problems of the technologies described above, the technical solution of the present invention is specifically as follows:

The present invention provides a phosphorescent material whose structural formula is shown in Chemical Formula 1:

Wherein, R ₁ to R ₃ each independently represent hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heterocyclic group, substituted Or unsubstituted C1-C60 alkylamino, or substituted or unsubstituted C6-C60 arylamino;

R ₄ to R ₇ each independently represent: hydrogen, isotopes of hydrogen, halogen, cyano, carboxyl, nitro, hydroxyl, sulfonic acid, phosphoric acid, boryl, substituted or unsubstituted silicon, substituted or unsubstituted Substituted C1-C20 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C1- C60 alkoxy, substituted or unsubstituted C1-C60 alkylamino, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C6-C60 aryloxy, or substituted or unsubstituted C6-C60 Arylthio; or linking with adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic ring, specifically a C3-C30 aliphatic or aromatic ring;

L is a link, or selected from substituted or unsubstituted C1-C60 alkyl, C3-C60 cycloalkyl, substituted or unsubstituted C6-C60 aryl, or C6-C60 heterocyclic group; or with Adjacent substituents are connected to form a substituted or unsubstituted monocyclic or polycyclic ring, specifically a C3-C30 aliphatic or aromatic ring;

Ar is a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C3-C60 heterocyclic group, a substituted or unsubstituted C1-C60 alkylamino group, or a substituted Or unsubstituted C6-C60 arylamino; preferably substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heterocyclic group, or substituted or unsubstituted C6-C60 arylamino;

R ₄ to R ₇ are at any position of the ring; the number of R ₄ and R ₅ is 0 to 4; the number of R ₆ and R ₇ is 0 to 3;

n is an integer of 0-3.

In the above technical scheme, L is preferably a link or a phenyl group.

In the above technical scheme, when L is connected with adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic ring, its carbon atom can be replaced with at least one heteroatom selected from nitrogen, oxygen, and sulfur.

In the above technical scheme, when R ₄ ~ R ₇ are respectively connected with adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic ring, their carbon atoms can be replaced with at least one selected from nitrogen, oxygen, sulfur heteroatoms.

In the above technical solution, most preferably, the phosphorescent material is selected from any one of the following structures:

The present invention also provides a method for preparing a phosphorescent material, comprising the following steps:

Step 1, the preparation of intermediate I

Dissolve compound 1 and compound 2 in a mixed solvent of toluene, ethanol and water, add Pd(PPh ₃ ) ₄ , K ₂ CO ₃ , and prepare intermediate I after the reaction;

Step 2, the preparation of intermediate II

Dissolving compound 3 and compound 4 in a mixed solvent of toluene, ethanol and water, adding Pd(PPh ₃ ) ₄ , K ₂ CO ₃ , and preparing intermediate II after the reaction;

Step 3, the preparation of intermediate IV

Mix intermediate II and IrCl ₃ ·3H ₂ O, heat, and prepare intermediate III after the reaction; then dissolve intermediate III in dichloromethane, and then add silver trifluoromethanesulfonate in isopropyl Alcoholic solution, intermediate IV is prepared after the reaction;

The preparation of the compound shown in step 4, chemical formula 1

Add absolute ethanol to intermediate IV and intermediate intermediate I, and prepare the compound shown in chemical formula 1 after the reaction is completed;

In the formula: the substituents and numbers of R ₁ -R ₇ , the limitations of L, Ar, and n are the same as those in Chemical Formula 1, and will not be repeated here.

In the above preparation method, the synthesis of intermediates I and II, the preferred solvent is a mixed solvent of toluene, ethanol and water, the molar ratio is between 1:2-3:2-3 and the reaction temperature does not exceed 100 ° C, the reaction time Not more than 24 hours. IrCl ₃ ·3H ₂ O and intermediate II were mixed in a solvent at a molar ratio of 1:2-4, and the mixture was heated at reflux before the diiridium dimer was isolated. During the preparation of the compound represented by Chemical Formula 1, the preferred solvent is alcohol or alcohol/water mixed solvent, such as ethanol and ethanol/water mixture. The molar ratio of primary and secondary ligands in the final product is determined from the approximate molar ratio (based on composition) of the reactants.

The present invention also provides an organic electroluminescent device prepared from the phosphorescent material represented by Chemical Formula 1 of the present invention.

The organic electroluminescent device includes: a first electrode, a second electrode and an organic layer placed between the two electrodes, wherein the organic layer contains the phosphorescent material shown in Chemical Formula 1 of the present invention.

The organic electroluminescent device includes a light-emitting layer, and the light-emitting layer contains the phosphorescent material represented by Chemical Formula 1 of the present invention.

The light-emitting layer of the organic electroluminescent device includes a host material and a dopant material, and the dopant material contains the phosphorescent material shown in Chemical Formula 1 of the present invention.

The beneficial effects of the present invention are:

The phosphorescent material provided by the invention adjusts the wavelength of the compound by selecting specific heterocyclic ligands for binding, and the obtained organometallic compound improves the luminous efficiency of the device and has a long service life after being used in an organic electroluminescent device.

The preparation method of the phosphorescent material provided by the invention has easy-to-obtain raw materials, simple synthesis process and high product yield.

The phosphorescent material of the present invention can be applied to OLED light-emitting devices, and compared with the comparative example, the voltage, efficiency and lifetime are all improved compared with known OLED materials.

Detailed ways

The following are implementation examples of the present invention. The following examples are provided to help the understanding of the present invention, and do not limit the scope of the present invention. In addition, the preparation methods of compounds that are not specifically listed in the examples of the present invention are methods commonly used in related industries, and the methods described in the examples can also be referred to when preparing other compounds.

Example 1: Compound PD10

Synthesis of intermediate 10-3

Accurately weigh 20 grams (67.8 mmol) of triphenylchlorosilane and add it to the reaction flask, 300 mL of toluene, 150 mL of ethanol, 150 mL of deionized water, nitrogen protection, and stir for 30 minutes, then add the raw material 2-phenylpyridine (4 - boric acid) 16.2 g (81.4 mmol), catalyst Pd (PPh ₃ ) ₄ 0.6 g (0.678 mol), potassium carbonate 18.57 g (134.6 mmol), heated to 90°C for 24 hours.

Post-treatment process: TLC monitoring until the reaction is complete. The temperature was lowered, the liquid was separated at rest, and the water layer was separated to keep the toluene layer. Add another 150 mL of water to wash the toluene layer once, separate the layers, dry the toluene layer, spin dry the toluene to obtain a dark solid. After passing through a silica gel column, first use dichloromethane: petroleum ether = 1:4 about 500mL to wash out the impurity spots, then use ethyl acetate: petroleum ether = 3:1 about 1000mL to wash out all the product spots, and spin dry to obtain a white solid. 18 g of the product was obtained with a yield of 65%.

Synthesis of Intermediate 10-6

Add 20 g (85.4 mmol) of the raw material 4-bromophenyl-2-pyridine and 12.5 g (10.25 mmol) of phenylboronic acid into the reaction flask, 200 mL of toluene, 100 mL of ethanol, 100 mL of deionized water, nitrogen protection, and then add the catalyst Pd ( PPh ₃ ) ₄ 0.1 g (0.854 mol), potassium carbonate 23.51 g (0.1708 mmol), heated to 90°C for 24 hours.

TLC monitoring until the reaction is complete. The temperature was lowered, the liquid was separated at rest, and the water layer was separated to keep the toluene layer. Add another 200 mL of water to wash the toluene layer once, separate the layers, dry the toluene layer, spin dry the toluene to obtain a dark solid. After passing through a silica gel column, first use dichloromethane: petroleum ether = 1:4 about 800mL to wash out the impurity spots, then use ethyl acetate: petroleum ether = 2:1 about 1500mL to wash out all the product spots, and spin dry to obtain a white solid. 15 g of the product was obtained with a yield of 70%.

Synthesis of Intermediate 10-7

Add 13.6 g (32.88 mmol) of intermediate 10-3 and 3.4 g (13.15 mmol) of iridium trichloride into a three-necked flask, then add 200 mL of ethylene glycol diethyl ether and 100 mL of water, protect with nitrogen, heat up to 140°C and stir to react 24 hours.

After 1 hour of reaction, a solid precipitated out, and the reaction was continued for 18 hours. The reaction was monitored by TLC, and the temperature was lowered until the reaction of the raw materials was completed. Suction filtration directly to obtain a yellow solid, which was first washed with 100 mL of ethanol, then with 100 mL of petroleum ether, and dried. 12.11 g of the product was obtained, yield: 70%, MW: 2104.47.

Synthesis of intermediate 10-8

Add 12.11 g (5.75 mol) of intermediate 10-7 into a three-necked flask, then add about 200 mL of dichloromethane, and stir at room temperature until it is completely dissolved. Then 4.6 g (17.25 mmol) of silver trifluoromethanesulfonate was dissolved in 20 mL of isopropanol. The prepared isopropanol solution was added dropwise into a three-necked flask, and reacted at room temperature for 24 hours.

TLC monitoring showed that the reaction of the raw materials was basically completed, and a dark solution was obtained by suction filtration, and 7.40 g of a dark oil was obtained by spin drying, with a yield of 100%. MW:1286.33

Synthesis of Compound PD10

Add 7.4 g (5.75 mol) of intermediate 10-8 into a three-necked flask, then add 150 mL of absolute ethanol and 9.6 g (11.5 mmol) of intermediate 10-6, and stir the reaction at 90°C for 24 hours, and a large amount of solids precipitate out.

TLC monitoring showed that the basic reaction of raw materials was completed. After suction filtration, the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 5.6 g of the product, with a yield of 76%, and the measured HPLC was 99%. MW: 1280.17.

Example 2: Compound PD25

Intermediate 25-8 was synthesized according to the method of Example 1.

Add 12.87g (10.0mmol) of intermediate 25-8 into a three-necked flask, then add 150mL of absolute ethanol and 5.22g (20.0mmol) of intermediate 25-6, and stir the reaction at 90°C for 24 hours, and a large amount of solids precipitate out. TLC monitoring showed that the basic reaction of raw materials was completed. After suction filtration, the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 9.2 g of the product, with a yield of 72%, and the measured HPLC was 99%. MW: 1277.52.

Example 3: Compound PD34

Add 12.87g (10.0mmol) of intermediate 34-8 into a three-necked flask, then add 150mL of absolute ethanol and 6.18g (20mmol) of intermediate 34-6, and stir the reaction at 90°C for 24 hours, and a large amount of solids precipitate out.

TLC monitoring showed that the basic reaction of raw materials was completed. After suction filtration, the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 10.34 g of product PD34, with a yield of 78%, and a HPLC value of 99%. MW: 1325.41.

Example 4: Compound PD47

Add 12.87g (10.0mmol) of intermediate 47-8 to a three-necked flask, then add 150mL of absolute ethanol and 9.96g (20mmol) of intermediate 47-6, stir and react at 90°C for 24 hours, and a large amount of solids precipitate out. TLC monitoring showed that the basic reaction of raw materials was completed. After suction filtration, the crude product of the target product was obtained, washed with about 50 mL of petroleum ether, and dried to obtain 10.35 g of the product PD47, with a yield of 72%, and a HPLC value of 99%. MW: 1438.40.

Example 5: Compound PD59

Add 13.9g (10.0mmol) of intermediate 59-8 into a three-necked flask, then add 150mL of absolute ethanol and 6.42g (20mmol) of intermediate 59-6, stir and react at 90°C for 24 hours, a large amount of solids precipitate out. TLC monitoring showed that the basic reaction of the raw materials was completed. After suction filtration, the crude product of the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 11.21 g of product PD59, with a yield of 78%, and a HPLC value of 99%. MW: 1437.49.

Example 6: Compound PD69

Add 12.87 g (10.0 mmol) of intermediate 69-8 into a three-necked flask, then add 150 mL of absolute ethanol and 6.94 g (20.0 mol) of intermediate 69-6, and stir the reaction at 90°C for 24 hours, and a large amount of solids precipitate out. TLC monitoring showed that the basic reaction of the raw materials was completed. After suction filtration, the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 9.95 g of the product, with a yield of 73%, and the measured HPLC value was 99%. MW: 1363.12.

Example 7 Compound PD7

Synthesis of Compound PD7

Add 7.4g (5.75mol) of intermediate 10-8 into a three-necked flask, then add 150mL of absolute ethanol and 4.8g (11.5mmol) of intermediate 10-3, and stir the reaction at 90°C for 24 hours, and a large amount of solids precipitate out.

TLC monitoring showed that the basic reaction of raw materials was completed. After suction filtration, the target product was obtained, rinsed with about 50 mL of petroleum ether, and dried to obtain 5.6 g of the product, with a yield of 80%, and the measured HPLC was 99.1%. MW: 1432.

The present invention also provides an organic electroluminescent device made of the phosphorescent material shown in Chemical Formula 1 of the present invention.

In order to further describe the present invention, more specific examples are listed below.

Example 8

Use the phosphorescent material of formula PD10 to prepare organic electroluminescence device, it is more specific:

The coating thickness is The ITO glass substrate is cleaned twice in distilled water, ultrasonically washed for 30 minutes, washed twice with distilled water, ultrasonically washed for 10 minutes, after the distilled water is cleaned, isopropanol, acetone, methanol and other solvents are ultrasonically washed in sequence and then dried. Transfer to the plasma cleaning machine, wash the above-mentioned substrate for 5 minutes, and send it to the vapor deposition machine. First, N1-(2-naphthyl)-N4, N4-bis(4-(2-naphthyl(phenyl)amino)phenyl)-N1-phenylbenzene-1,4- Diamine ("2-TNATA") 60nm, followed by evaporated NPB 60nm, host substance 4,4'-N,N'-biphenyldicarbazole ("CBP") and dopant substance compound PD10 95:5 by weight Compared with mixed evaporation 30nm, evaporation hole blocking layer ("BAlq") 10nm thickness, evaporation electron transport layer "Alq3" 40nm thickness, evaporation electron injection layer LiF0.2nm, evaporation cathode Al 150nm form prepared Electromechanical Luminescent Devices. The performance and luminous characteristics of the obtained device were tested by using a KEITHLEY 2400 source measure unit and a CS-2000 spectroradiance luminance meter to evaluate the driving voltage, luminous brightness and luminous efficiency.

Example 9

An organic electroluminescence device was prepared according to the method of Example 8, except that the dopant compound of the light-emitting layer was replaced by compound PD10 with compound PD25.

Example 10

An organic electroluminescence device was prepared according to the method of Example 8, except that the dopant compound of the light-emitting layer was replaced by compound PD34 from compound PD10.

Example 11

An organic electroluminescent device was prepared according to the method of Example 8, except that the dopant compound of the light-emitting layer was replaced by compound PD47 from compound PD10.

Example 12

An organic electroluminescent device was prepared according to the method of Example 8, except that the dopant compound of the light-emitting layer was replaced by compound PD10 with compound PD59.

Example 13

An organic electroluminescence device was prepared according to the method of Example 8, except that the dopant compound of the light emitting layer was replaced by compound PD69 from compound PD10.

Example 14

An organic electroluminescent device was prepared according to the method of Example 8, except that the dopant compound of the light-emitting layer was replaced by compound PD10 with compound PD7.

Comparative example 1

An organic electroluminescent device was prepared according to the same method as in Example 8, except that the dopant compound was replaced by the compound PD10 with the following compound:

Table 1 Embodiment 8～Example 14 and comparative example 1 in organic electroluminescent device detection result

compound Driving voltage (v) efficiency lifespan (h) color Ir(ppy)₃ 1.0 1.0 1.0 green PD10 0.57 3.9 5.2 green PD24 0.55 3.9 4.7 green PD34 0.56 3.8 5.5 green PD47 0.53 3.7 5.0 green PD59 0.56 3.8 4.9 green PD69 0.55 3.8 5.1 green PD7 0.54 3.8 4.8 green

The device test performance is based on the device comparative example 1, and the performance indicators of the comparative example 1 are set to 1.0. It can be seen from the results in Table 1 that the phosphorescent material of the present invention can be applied to OLED light-emitting devices, and compared with the comparative example, the voltage, efficiency and lifetime are all improved compared with known OLED materials.

Apparently, the above-mentioned embodiments are only examples for clear description, rather than limiting the implementation. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (10)

1. A phosphorescent material, characterized in that its structural formula is as shown in Chemical Formula 1: Wherein, R ₁ to R ₃ each independently represent hydrogen, deuterium, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heterocyclic group, substituted Or unsubstituted C1-C60 alkylamino, or substituted or unsubstituted C6-C60 arylamino; R ₄ to R ₇ each independently represent: hydrogen, isotopes of hydrogen, halogen, cyano, carboxyl, nitro, hydroxyl, sulfonic acid, phosphoric acid, boryl, substituted or unsubstituted silicon, substituted or unsubstituted Substituted C1-C20 alkyl, substituted or unsubstituted C6-C60 aryl, substituted or unsubstituted C3-C60 heteroaryl, substituted or unsubstituted C3-C60 cycloalkyl, substituted or unsubstituted C1- C60 alkoxy, substituted or unsubstituted C1-C60 alkylamino, substituted or unsubstituted C6-C60 arylamino, substituted or unsubstituted C6-C60 aryloxy, or substituted or unsubstituted C6-C60 Arylthio; or linking with adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic ring, specifically a C3-C30 aliphatic or aromatic ring; L is a link, or selected from substituted or unsubstituted C1-C60 alkyl, C3-C60 cycloalkyl, substituted or unsubstituted C6-C60 aryl, or C6-C60 heterocyclic group; or with Adjacent substituents are connected to form a substituted or unsubstituted monocyclic or polycyclic ring, specifically a C3-C30 aliphatic or aromatic ring; Ar is a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C6-C60 aryl group, a substituted or unsubstituted C3-C60 heterocyclic group, a substituted or unsubstituted C1-C60 alkylamino group, or a substituted Or unsubstituted C6-C60 arylamino; R ₄ to R ₇ are in any position of the ring; the number of R ₄ and R ₅ is 0 to 4; the number of R ₆ and R ₇ is 0 to 3; n is an integer of 0-3. 2. The phosphorescent material according to claim 1, wherein L is a link or a phenyl group. 3. The phosphorescent material according to claim 1, wherein when L is connected with an adjacent substituent to form a substituted or unsubstituted monocyclic or polycyclic ring, its carbon atom is replaced with at least one selected from nitrogen , oxygen, and sulfur heteroatoms. 4. The phosphorescent material according to claim 1, characterized in that, when R ₄ to R ₇ are respectively connected with adjacent substituents to form a substituted or unsubstituted monocyclic or polycyclic ring, their carbon atoms are replaced by At least one heteroatom selected from nitrogen, oxygen, sulfur. 5. The phosphorescent material according to claim 1, characterized in that it is selected from any one of the following structures: 6. A method for preparing the phosphorescent material according to any one of claims 1-5, comprising the following steps: Step 1, the preparation of intermediate I Dissolve compound 1 and compound 2 in a mixed solvent of toluene, ethanol and water, add Pd(PPh ₃ ) ₄ , K ₂ CO ₃ , and prepare intermediate I after the reaction; Step 2, the preparation of intermediate II Dissolving compound 3 and compound 4 in a mixed solvent of toluene, ethanol and water, adding Pd(PPh ₃ ) ₄ , K ₂ CO ₃ , and preparing intermediate II after the reaction; Step 3, the preparation of intermediate IV Mix intermediate II and IrCl ₃ ·3H ₂ O, heat, and prepare intermediate III after the reaction; then dissolve intermediate III in dichloromethane, and then add silver trifluoromethanesulfonate in isopropyl Alcoholic solution, intermediate IV is prepared after the reaction; The preparation of the compound shown in step 4, chemical formula 1 Add absolute ethanol to intermediate IV and intermediate intermediate I, and prepare the compound shown in chemical formula 1 after the reaction is completed; 7. An organic electroluminescent device prepared from the phosphorescent material according to any one of claims 1-5. 8. The organic electroluminescence device according to claim 7, characterized in that, comprising: a first electrode, a second electrode and an organic layer placed between the two electrodes, wherein the organic layer contains The phosphorescent material according to any one of claims 1-5. 9. The organic electroluminescent device according to claim 8, characterized in that it comprises a light-emitting layer containing the phosphorescent material according to any one of claims 1-5. 10. The organic electroluminescent device according to claim 9, characterized in that, the light-emitting layer comprises a host material and a dopant material, and the dopant material contains the phosphorescent material according to any one of claims 1-5 .