An organic light-emitting material and an organic electroluminescent device

Abstract

The application provides an organic light-emitting material and an organic electroluminescent device, and has a compound, wherein R1 to R3 are each independently selected from hydrogen, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group, and Ar1-Ar2 are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl. The technical scheme of the application can be used as an electron transport material, and the OLED device matched with the electron transport material has good performance.

Description

Technical Field

[0001] This invention relates to the field of organic electroluminescent devices, and more specifically, to an organic light-emitting material and an organic electroluminescent device having the same. Background Technology

[0002] Organic light-emitting displays (OLEDs) have a series of advantages, such as self-illumination, low-voltage DC drive, all-solidification, wide viewing angle, light weight, and simple composition and process. Compared with liquid crystal displays (LCDs), OLEDs do not require a backlight, have a wide viewing angle, low power consumption, and their response speed can be up to 1,000 times that of LCDs. However, their manufacturing cost is lower than that of LCDs with the same resolution. Therefore, organic light-emitting devices have broad application prospects.

[0003] With the continuous advancement of OLED technology in the fields of lighting and display, people are paying more attention to the research on high-efficiency organic materials that affect the performance of OLED devices. An efficient and long-life organic electroluminescent device is usually the result of the optimized combination of device structure and various organic materials.

[0004] The most common OLED device structures typically include the following types of organic materials: hole injection materials, hole transport materials, electron transport materials, and various luminescent materials (dyes or doped guest materials) and corresponding host materials. Currently known electron transport materials do not perform ideally, and the industry urgently needs to develop new electron transport materials.

[0005] Therefore, the present invention provides an organic light-emitting material with advantages such as low voltage and high efficiency, and an organic electroluminescent device having the same. Summary of the Invention

[0006] In view of the problems in the prior art, the purpose of this invention is to provide an organic light-emitting material and an organic electroluminescent device having the same, which not only has a lower voltage, but also has higher efficiency and lifespan.

[0007] According to one aspect of the present invention, an organic light-emitting material is provided having the structure shown in Formula I:

[0008]

[0009] R1 to R3 are each independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, and Ar1 to Ar2 are each independently selected from substituted or unsubstituted aryl or substituted or unsubstituted heteroaryl.

[0010] Preferably, R1 to R3 are each independently selected from hydrogen, substituted or unsubstituted C1-C. 10Alkyl, substituted or unsubstituted C2-C 10 alkenyl, substituted or unsubstituted C6-C 30 aryl or substituted or unsubstituted C3-C 30 Mixed aromatic compounds.

[0011] Preferably, R1 to R3 are each independently selected from hydrogen, substituted or unsubstituted C1-C. 10 Alkyl or substituted or unsubstituted C6-C 30 Aryl.

[0012] Preferably, R1 and R2 are the same.

[0013] Preferably, each of Ar1-Ar2 is independently selected from substituted or unsubstituted C6-C. 60 aryl or substituted or unsubstituted C3-C 60 Mixed aromatic compounds.

[0014] Preferably, at least one of Ar1-Ar2 is a phenyl group.

[0015] Preferably, each of Ar1-Ar2 is independently selected from substituted or unsubstituted C6-C. 60 aryl or substituted or unsubstituted O-containing C3-C 60 Mixed aromatic compounds.

[0016] Preferably, the structure of Formula I is as follows:

[0017]

[0018]

[0019] According to another aspect of the present invention, an organic electroluminescent device is also provided, wherein the organic electroluminescent device is doped with the above-described organic light-emitting material.

[0020] Preferably, the organic light-emitting material is contained in the electron transport layer or light-emitting layer of the organic electroluminescent device.

[0021] The present invention discloses an organic light-emitting material and an organic electroluminescent device having the same. The symmetrical organic light-emitting material contains N heterocyclic compounds and triarylamine structures, which can form a stable heterocyclic organic aromatic system, has a reversible electrochemical reduction reaction, suitable HOMO and LUMO energy levels, and rich photoelectric properties. It enables the device to have high electron mobility, low voltage and other characteristics, and can be used as an electron transport material in electroluminescent devices. Detailed Implementation

[0022] Exemplary implementations will now be described more fully with reference to embodiments. However, these exemplary implementations can be implemented in many forms and should not be construed as limited to the implementations set forth herein. Rather, these implementations are provided so that the invention will be thorough and complete, and will fully convey the concept of the exemplary implementations to those skilled in the art.

[0023] In an embodiment of the present invention, an organic light-emitting material and an organic electroluminescent device having the same are provided, comprising a compound having the structure shown in Formula I:

[0024]

[0025] R1 to R3 are each independently selected from hydrogen, substituted or unsubstituted C1-C. 10 Alkyl, substituted or unsubstituted C2-C 10 alkenyl, substituted or unsubstituted C6-C 30 aryl or substituted or unsubstituted C3-C 30 heteroaryl groups. Ar1-Ar2 are each independently selected from substituted or unsubstituted C6-C. 60 aryl or substituted or unsubstituted C3-C 60 Mixed aromatic compounds.

[0026] This invention discloses an organic light-emitting material and an organic electroluminescent device having the same. The material employs a symmetrical organic light-emitting structure consisting of an N-heterocyclic compound and a triarylamine, which can form a stable heterocyclic organic aromatic system, resulting in good stability and higher efficiency. It can be used as an electron transport material, and OLED devices equipped with it exhibit excellent lifespan.

[0027] In embodiments of the present invention, the compound with the structure shown in Formula I is preferred:

[0028]

[0029]

[0030] The method for synthesizing compounds with the structure shown in Formula I is as follows. Those skilled in the art should understand that the above preparation method is merely an exemplary example, and therefore, no specific limitation is made to the preparation method. Only the following representative synthetic route is provided as an example. Compounds for which no preparation method is provided are also commercially available and will not be described in detail. Those skilled in the art can synthesize these compounds themselves using the general formula compound synthesis method provided by this invention and existing technology without any difficulty.

[0031]

[0032] A mixture of starting material A (10.0 mmol), starting material B (5.0 mmol), potassium carbonate (10.0 mmol), and tetraphenylphosphine palladium (0.25 mmol) was dissolved in 60 mL of toluene and stirred at 90 °C for 3 hours under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature and extracted twice with dichloromethane and water. The organic phase was evaporated to dryness with anhydrous magnesium sulfate and then subjected to column chromatography to obtain the target structure.

[0033] The present invention is described in detail below with specific embodiments:

[0034] Compound 1

[0035] The synthetic method for preparing compound 1 is as follows:

[0036]

[0037] Under nitrogen atmosphere, add 70 mL of dry toluene and 35 mL of water to a 200 mL two-necked flask containing a mixture of raw material 1 (5.0 mmol), raw material 2 (5.0 mmol), potassium carbonate (10.0 mmol), and tetraphenylphosphine palladium (0.25 mmol).

[0038] The mixture was refluxed at 100–120 °C for 12–24 hours. After cooling to room temperature, the mixture was extracted with DCM / water. The combined organic layers were dried over magnesium sulfate, filtered, and rotary evaporated. The residue was purified by silica gel column chromatography and then recrystallized from toluene to give a solid compound, which was purified by silica gel column chromatography to give compound 1 of the reaction, in 80% yield.

[0039] Compounds 1-4 can be prepared in a similar manner, as shown in Table 1 below.

[0040] Table 1: Compound Synthesis Table

[0041]

[0042]

[0043] Compounds 1-4 above all have high mobility and suitable energy levels, and can be used as electron transport materials; the compounds of the present invention also have high thermal stability, ensuring the thermal stability of the material during the vapor deposition process.

[0044] Controlled Trial

[0045] Examples 1-4

[0046] Organic light-emitting elements 1-4 were prepared sequentially using compounds 1-4 prepared according to the present invention.

[0047] The organic light-emitting elements 1-4, from bottom to top, include an anode substrate, a hole injection layer (HIL), a hole transport layer (HTL), an emissive layer (EML), an electron transport layer (ETL), an electron injection layer, and a cathode.

[0048] The constituent materials of each layer of organic light-emitting elements 1-6 are as follows:

[0049] Anode substrate: ITO (Indium Tin Oxide);

[0050] Hole injection layer: hexanitrile hexaazabenzophenanthrene (HAT-CN), with a thickness of 10 nm;

[0051] Hole transport layer: NPB as shown below, with a thickness of 70nm;

[0052] Emitting layer: host material GH, guest material Ir(ppy)3, host-guest material mass ratio is 95:5; thickness is 30nm;

[0053] Electron transport layer: The materials are compounds 1-4 from the embodiments of the present invention, and the thickness is 40 nm;

[0054] Electron injection layer: The material is LiF, and the thickness is 1 nm;

[0055] Cathode: Aluminum, 100 nm thick.

[0056] Comparative Example 1

[0057] Organic light-emitting element 5 was prepared. The difference between organic light-emitting element 5 and organic light-emitting element 1-4 prepared by compounds 1-4 is that the electron transport layer material in organic light-emitting element 5 uses the following formula TPBI instead of compound 1-4, and the rest is the same.

[0058] The relevant molecular formula structures are shown below:

[0059]

[0060] The specific steps are as follows: Clean the ITO anode layer on the transparent substrate by ultrasonic cleaning with deionized water, acetone, and ethanol for 15 minutes each, followed by treatment in a plasma cleaner for 2 minutes. Vacuum evaporation is used to deposit the following layer structure: a hole injection layer of 10 nm thick HAT-CN material; a hole transport layer of 70 nm thick NPB material; a light-emitting layer, using GH as the host material and Ir(ppy)3 as the dopant material at a mass ratio of 95:5, with a thickness of 30 nm; on the light-emitting layer, deposit compound 1-4 or TPBI electron transport material with a thickness of 40 nm; on the electron transport layer, deposit an electron injection layer of LiF with a thickness of 1 nm, which is for electron injection; on the electron injection layer, vacuum evaporate a cathode Al (100 nm).

[0061] Performance testing

[0062] The organic light-emitting elements 1-4 prepared in Examples 1-4 of the present invention and the organic light-emitting element 5 prepared in Comparative Example 1 were subjected to the following performance tests:

[0063] OLEDs are characterized in a standard manner. For this purpose, the electroluminescence spectrum, power efficiency (measured in cd / A), and voltage (in V) are determined based on the current-voltage-luminance characteristic (JUL characteristic). For selected tests, lifetime is measured. The lifetime is defined as the time after which the luminance has decreased from a specific initial luminance to a specific percentage. The number T95 indicates that the specified lifetime is the time when the luminance has decreased to 95% of the initial luminance, i.e., from 1000 cd / m² to 950 cd / m². Different initial luminances are selected based on the emitted color. The lifetime value can be converted to a value for other initial luminances using conversion formulas known to those skilled in the art.

[0064] The performance test results are shown in Table 2:

[0065] Table 2: Test Results

[0066]

[0067] As can be seen from the performance data in Table 2, when the compound provided by the present invention is used as an electron transport material for organic electroluminescent devices, the device has high device efficiency, low operating voltage, and long service life.

[0068] In summary, the organic light-emitting material and the organic electroluminescent device having the present invention not only have a lower voltage but also a higher efficiency.

[0069] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An organic light-emitting material, characterized in that, It has the structure shown in Equation I: Formula I Wherein, R1 is methyl or hydrogen, R2 is methyl, hydrogen or phenyl, R3 is methyl, Ar1 is phenyl, and Ar2 is phenyl.

2. An organic light-emitting material, characterized in that: It has the following structure: , , , or .

3. An organic electroluminescent device, characterized in that: The organic electroluminescent device is doped with the organic light-emitting material according to claim 1 or 2.

4. The organic electroluminescent device according to claim 3, characterized in that: The organic light-emitting material is contained in the electron transport layer of the organic electroluminescent device.

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