Oxygen-containing heterocyclic compound, organic electroluminescent device and display device

Abstract

The invention provides an oxygen-containing heterocyclic compound, an organic electroluminescent device and a display device, and relates to the technical field of organic electroluminescent materials. Through structural design, the obtained oxygen-containing heterocyclic compound can be used as a main body material of a light-emitting layer of the organic light-emitting device, so that the organic light-emitting device has relatively low driving voltage, relatively high current efficiency and relatively long service life.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic optoelectronics, and particularly relates to an oxygen-containing heterocyclic compound, an organic electroluminescent device and a display device. Background Art

[0002] Organic electroluminescent devices (OLEDs) have become one of the most promising new display technologies due to their advantages such as self-luminescence, low driving voltage, high contrast ratio, wide viewing angle, etc. Through the unremitting efforts of scientific researchers and enterprise R & D, organic electroluminescent technology has initially entered the industrialization stage.

[0003] After decades of development, the OLED device structure has gradually evolved from the initial single-layer and double-layer structures to the current multi-layer structures, mainly including an anode, a hole injection layer, a hole transport layer, an electron blocking / exciton blocking layer, an organic light-emitting layer, a hole blocking / exciton blocking layer, an electron transport layer, an electron injection layer, and a metal cathode.

[0004] Currently, organic electroluminescence (OLED) has become the mainstream display technology. Correspondingly, various new OLED materials have been developed. Therefore, there is an urgent need in this field to develop more types of organic thin film layer materials with higher performance to meet the higher requirements for organic electroluminescent devices. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an oxygen-containing heterocyclic compound, an organic electroluminescent device and a display device. The oxygen-containing heterocyclic compound obtained by the structural design of the present invention can be used as the host material of the light-emitting layer, enabling the organic electroluminescent device to have a lower driving voltage, a higher current efficiency and a longer lifespan.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an oxygen-containing heterocyclic compound having a structure represented by formula BH-A:

[0008]

[0009] In formula BH-A, Ar is selected from any one of C6-C40 aryl groups (for example, C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, C40 aryl groups), C12-C20 heteroaryl groups (for example, C12, C14, C16, C18, C20 heteroaryl groups);

[0010] Each hydrogen atom in formula BH-A can be independently replaced by any one of -D, -F, cyano, C1-C5 alkyl (such as methyl, ethyl, propyl), C1-C5 alkoxy (such as methoxy, ethoxy, propoxy), C6-C20 aryl (such as C6, C8, C10, C12, C16, C20 aryl), and C12-C20 heteroaryl (such as C12, C14, C16, C18, C20 heteroaryl).

[0011] In the present invention, "D" represents a deuterium atom, and the same applies hereinafter.

[0012] Preferably, all hydrogen atoms in the Ar are replaced by -D.

[0013] Preferably, Ar is selected from any one of phenyl, biphenyl, terphenyl, fluorenyl, naphthyl, triphenylene, fluoranthenyl, dibenzofuranyl, dibenzothiophenyl, naphthodibenzofuranyl, naphthodibenzothiophenyl.

[0014] Preferably, the structure of the oxygen-containing heterocyclic compound is selected from any one of formulas BH-A-1 to BH-A-6:

[0015]

[0016] In formulas BH-A-1 to BH-A-6, Ar is selected from any one of C6-C40 aryl (such as C6, C8, C10, C12, C16, C20, C24, C28, C30, C32, C36, C40 aryl) and C12-C20 heteroaryl (such as C12, C14, C16, C18, C20 heteroaryl). Each hydrogen atom in formulas BH-A-1 to BH-A-6 can be independently replaced by any one of -D, -F, cyano, C1-C5 alkyl (such as methyl, ethyl, propyl), C1-C5 alkoxy (such as methoxy, ethoxy, propoxy), C6-C20 aryl (such as C6, C8, C10, C12, C16, C20 aryl), and C12-C20 heteroaryl (such as C12, C14, C16, C18, C20 heteroaryl).

[0017] Preferably, the C6-C40 aryl is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthofluorenyl, pyrenyl, perylenyl, spirofluorene, triphenylene, fluoranthenyl, hydrobenzanthryl, indeno[1,2-b]fluorene, benzo[ghi]fluorene, dibenzo[ghi]fluorene, naphtho[2,3-b]fluorene, benzo[naphtho[2,3-b]fluorene].

[0018] Preferably, the C12-C20 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, benzodibenzofuranyl, benzodibenzothiophenyl, dinaphthofuranyl, and dinaphthothiophenyl.

[0019] Preferably, the C6-C20 aryl group is selected from any one of phenyl, biphenyl, and naphthyl.

[0020] Preferably, each hydrogen atom in the formula BH-A can be independently substituted with any one of -D, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, phenyl, naphthyl, dibenzothiophenyl, and dibenzofuranyl.

[0021] Preferably, the oxygen-containing heterocyclic compound is selected from any one of the following compounds:

[0022]

[0023]

[0024]

[0025] Preferably, the oxygen-containing heterocyclic compound is selected from any one of the following Compounds 1-15:

[0026]

[0027] It should be noted that there is no special limitation on the preparation method of the oxygen-containing heterocyclic compound in the present invention, and the commonly used preparation methods in the art are applicable.

[0028] In a second aspect, the present invention provides an organic electroluminescent device, which includes an anode, a cathode, and an organic thin film layer disposed between the anode and the cathode;

[0029] The material of the organic thin film layer includes the oxygen-containing heterocyclic compound described above.

[0030] Preferably, the organic thin film layer includes a light-emitting layer, and the material of the light-emitting layer includes the oxygen-containing heterocyclic compound described above.

[0031] Preferably, the material of the light-emitting layer includes a host material and a doping material, and the host material includes the oxygen-containing heterocyclic compound described above.

[0032] The present invention does not impose special restrictions on the doping material of the light-emitting layer, and the commonly used doping materials for the light-emitting layer in the art are applicable.

[0033] In a third aspect, the present invention provides a display device, which includes the organic electroluminescent device described above.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] In the present invention, an oxygen-containing heterocyclic compound with a specific structure is obtained through structural design. Using this oxygen-containing heterocyclic compound as a material for an organic electroluminescent device, especially as the host material of the light-emitting layer, the prepared organic electroluminescent device has a lower driving voltage, a higher current efficiency, and a longer lifespan. Detailed implementation manners

[0036] To facilitate the understanding of the present invention, the following examples are listed. Those skilled in the art should understand that the examples are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0037] Preparation Example 1

[0038] This preparation example provides an intermediate M-4 and its synthesis method, and the synthesis method is as follows:

[0039]

[0040] 1) Synthesis of intermediate M-1

[0041] Under nitrogen protection, 120 mL of toluene, 60 mL of ethanol, and 60 mL of water are sequentially added to a 500 mL three-necked flask. Then, 1-bromodibenzofuran-2-ol (40.0 mmol), 9-anthraceneboronic acid (48.0 mmol), sodium bicarbonate (120.0 mmol), and tetrakis(triphenylphosphine)palladium (0.4 mmol) are added. The temperature is slowly raised to reflux and reacted for 8 h. After cooling to room temperature, 5% dilute hydrochloric acid is added to adjust the pH value to 6. Liquid separation is performed, and the aqueous phase is extracted once with toluene. The organic phases are combined. After the organic phase is washed with water, it is dried with magnesium sulfate. After filtering off the magnesium sulfate, the solvent is removed under reduced pressure, and crystallization is carried out with a mixed solvent of toluene and ethanol to obtain intermediate M-1 (10.0 g).

[0042] The intermediate M-1 is subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) is: 360.12.

[0043] 2) Synthesis of intermediate M-2

[0044] Under nitrogen protection, 300 mL of DCM is added to a 500 mL three-necked flask. Then, intermediate M-1 (25 mmol) and pyridine (50 mmol) are added. The temperature is cooled to 0 °C, and trifluoromethanesulfonic anhydride (30 mmol) is slowly added dropwise. After the addition is complete, the reaction is carried out at 0 °C for 1 h. Water is added for liquid separation, and the aqueous phase is extracted once with DCM. The organic phases are combined. After the organic phase is washed with water, it is dried with magnesium sulfate. After filtering off the magnesium sulfate, the solvent is removed under reduced pressure, and crystallization is carried out with a mixed solvent of toluene and ethanol to obtain intermediate M-2 (9.9 g).

[0045] The intermediate M-2 was detected by mass spectrometry, and the mass-to-charge ratio (m / z) was: 492.06.

[0046] Synthesis of intermediate M-3

[0047] Under nitrogen protection, 300 mL of DMF was added to a 500 mL three-necked flask, and then intermediate M-2 (20 mmol), LiCl (60 mmol), DBU (30 mmol), and Pd(PPh3)2Cl2 (0.2 mmol) were added. The temperature was slowly raised to 140 °C and reacted for 10 h. Water and ethyl acetate were added, and liquid separation was performed. The aqueous phase was extracted once with ethyl acetate. The organic phases were combined, washed with water, dried over magnesium sulfate, filtered to remove magnesium sulfate, and then the solvent was removed under reduced pressure. Crystallization was performed using a mixed solvent of toluene and ethanol to obtain intermediate M-3 (3.6 g).

[0048] The intermediate M-3 was detected by mass spectrometry, and the mass-to-charge ratio (m / z) was: 342.10.

[0049] Synthesis of intermediate M-4

[0050] Under nitrogen protection, 70 mL of DMF was added to a 250 mL three-necked flask, and then intermediate M-3 (10 mmol) and NBS (11 mmol) were added. The reaction was carried out at room temperature for 5 h. An aqueous solution of 5 wt% sodium bisulfite was slowly added to precipitate a solid, and the mixture was stirred for 1 h. Filtration was performed by suction, and the filter cake was washed with water until neutral. After drying, column chromatography separation was carried out, and elution was performed with petroleum ether:ethyl acetate = 20:1 (volume ratio) to obtain intermediate M-4 (1.1 g).

[0051] The intermediate M-4 was detected by mass spectrometry, and the two peaks with the largest mass-to-charge ratio (m / z) were: 420.01 & 422.01.

[0052] Preparation Examples 2 to 4

[0053] Preparation Examples 2 to 4 respectively provided an intermediate M-5 to M-7. The synthesis method was referred to that of intermediate M-4, except that 1-bromodibenzofuran-2-ol in Preparation Example 1 was replaced with an equimolar amount of the corresponding other dibenzofuran compounds (see Table 1 for details), and other conditions were the same as those of the synthesis method of intermediate M-4. The intermediate M-5 to M-7 were detected by mass spectrometry, and the test data are shown in Table 1 below.

[0054] Table 1 Dibenzofuran compounds in Preparation Examples 2 to 4 and structures of the prepared intermediates

[0055]

[0056]

[0057] Among them, the NMR data of intermediate M-6 are as follows: 1H-NMR (Bruker, Switzerland, Avance II 400 MHz nuclear magnetic resonance spectrometer, CDCl3), δ 8.91 (s, 1H), δ 8.52 (m, 1H), 8.27 (s, 1H), δ 8.17 (m, 1H), δ 8.06 (m, 1H), δ 7.99 (m, 1H), δ 7.69 - 7.63 (m, 2H), δ 7.60 - 7.53 (m, 2H), 7.46 (m, 1H), 7.39 (m, 1H), 7.30 (m, 1H).

[0058] Synthesis Example 1

[0059] This synthesis example provides a compound 1, and its synthesis method is as follows:

[0060]

[0061] Under the protection of nitrogen, 90 mL of toluene, 45 mL of ethanol and 45 mL of water were successively added into a 500 mL three-necked flask, and then intermediate M-4 (20.0 mmol), phenylboronic acid (24.0 mmol), potassium carbonate (30.0 mmol) and tetrakis(triphenylphosphine)palladium (0.2 mmol) were added. The temperature was slowly raised to reflux for 8 h, cooled to room temperature, water was added for liquid separation, the aqueous phase was extracted with toluene once, the organic phases were combined, after washing with water, the organic phase was dried with magnesium sulfate, magnesium sulfate was removed by filtration, the solvent was removed under reduced pressure, and the compound 1 (6.2 g) was obtained by crystallization with a mixed solvent of chlorobenzene and ethanol.

[0062] The mass spectrometry detection of compound 1 was carried out, and the mass-to-charge ratio (m / z) was: 418.14.

[0063] Synthesis Examples 2 - 15

[0064] Synthesis Examples 2 - 15 respectively provide compounds 2 - 15. Their synthesis methods refer to the synthesis method of compound 1. The difference is only that phenylboronic acid is replaced by an equimolar amount of other boric acid compounds (see Table 2 for details), and intermediate M-4 is replaced by an equimolar amount of other intermediates (M-5 - M-7) (see Table 2 for details). Other conditions are the same as those in the synthesis method of compound 1. The mass spectrometry detection of the synthesized compounds was carried out, and the test data are shown in Table 2.

[0065] Table 2 Intermediate structures, boric acid compounds and structures of the synthesized compounds in Synthesis Examples 2 - 15

[0066]

[0067]

[0068]

[0069]

[0070]

[0071] For compounds with unspecified specific synthesis methods, the synthesis can be carried out by referring to the above examples and combining the common general knowledge in the art.

[0072] The specific structures of some substances used in the following application examples and application comparative examples are as follows:

[0073]

[0074] Application Example 1

[0075] This application example provides an organic electroluminescent device, using Compound 1 provided in Synthesis Example 1 of the present invention as the host material of the light-emitting layer;

[0076] The structure of the organic electroluminescent device is: ITO / HT(40nm) / Host material of the light-emitting layer: BD-23%(30nm) / TPBI(30nm) / LiF(0.5nm) / Al(150nm); where HT is the hole transport layer, TPBI is the electron transport layer, LiF is the electron injection layer, and Al is the cathode.

[0077] The preparation method of the above organic electroluminescent device is as follows:

[0078] The glass substrate coated with the ITO transparent conductive layer (as the anode) is ultrasonically treated in a cleaning agent, then rinsed in deionized water, ultrasonically degreased in a mixed solvent of acetone and ethanol, baked in a clean environment until completely dehydrated, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam on the surface to improve the surface properties and enhance the bonding ability with the hole layer.

[0079] The materials are placed in a vacuum chamber, evacuated to 1×10 -5 ~1×10 -6 Pa, and then vacuum-evaporated onto the cleaned ITO substrate in sequence. Among them, the host material of the light-emitting layer: BD-23%(30nm) means that in the device, the host material of the light-emitting layer and BD-2 are co-evaporated in a volume ratio of 97:3 to form the light-emitting layer, and the thickness of the light-emitting layer is 30nm.

[0080] Application Examples 2-10

[0081] Application Examples 2-10 respectively provide an organic electroluminescent device, which is only different from Application Example 1 in that the host material of the light-emitting layer is different (see Table 3 for details), and other conditions are the same as those in Application Example 1.

[0082] Application Comparative Examples 1-3

[0083] Application Comparative Examples 1 to 3 each provide an organic electroluminescent device, which is only different from Application Example 1 in that the host material of the light-emitting layer is different (see Table 3 for details), and other conditions are the same as those in Application Example 1.

[0084] Performance Test

[0085] Test the driving voltage, current efficiency, and lifetime LT90 of the OLED devices provided above; among them, LT90 refers to the time required for the current density to remain unchanged while maintaining the initial brightness of 1000 nit and the brightness to drop to 90% of the original brightness. The test items include the brightness, driving voltage, and current efficiency of the organic electroluminescent device. The data of the driving voltage, current efficiency, and LT90 are all relative values at a brightness of 1000 cd / m 2 (based on Application Comparative Example 1).

[0086] The performance test results of the organic electroluminescent device are shown in Table 3.

[0087] Table 3 Host materials of the light-emitting layer and device performance test results of Application Examples 1-10 and Application Comparative Examples 1-3

[0088]

[0089]

[0090] It can be seen from the content of Table 3 that the oxygen-containing heterocyclic compound provided by the present invention can be used as the host material of the light-emitting layer of an organic electroluminescent device, enabling the organic electroluminescent device to have a lower driving voltage, a higher current efficiency, and a longer lifetime.

[0091] The present invention uses the above embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. An oxygen-containing heterocyclic compound, characterized in that The oxygen-containing heterocyclic compound has a structure as shown in formula BH-A: In formula BH-A, Ar is selected from any one of C6-C40 aryl and C12-C20 heteroaryl; The hydrogen atoms in formula BH-A may be independently substituted by any one of -D, -F, -cyano, C1-C5 alkyl, C1-C5 alkoxy, C6-C20 aryl, and C12-C20 heteroaryl.

2. The oxygen-containing heterocyclic compound according to claim 1, characterized in that All hydrogen atoms in Ar are replaced by -D.

3. The oxygen-containing heterocyclic compound according to claim 1, characterized in that The Ar is selected from any one of phenyl, biphenyl, terphenyl, fluorenyl, naphthyl, triphenylene, fluoranthenyl, dibenzofuranyl, dibenzothienyl, naphthodibenzofuranyl and naphthodibenzothienyl.

4. The oxygen-containing heterocyclic compound according to claim 1, characterized in that The structure of the oxygen-containing heterocyclic compound is selected from any one of formulas BH-A-1 to BH-A-6: In formulas BH-A-1 to BH-A-6, Ar is selected from any one of C6 to C40 aromatic groups and C12 to C20 heteroaromatic groups, and the hydrogen atoms in formulas BH-A-1 to BH-A-6 can each independently be substituted by any one of -D, -F, -cyano, C1 to C5 alkyl, C1 to C5 alkoxy, C6 to C20 aromatic groups, and C12 to C20 heteroaromatic groups.

5. The oxygen-containing heterocyclic compound according to claim 1, characterized in that The C6-C40 aryl group is selected from any one of phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, phenanthryl, fluorenyl, benzofluorenyl, dibenzofluorenyl, naphthfluoroenyl, pyrenyl, peryl, spirofluorenyl, triphenylene, fluoranthenyl, hydrogenated benzanthryl, indenofluorenyl, benzoindenofluorenyl, dibenzoindenofluorenyl, naphthfluoroenyl, and benzonaphthfluoroenyl; The C12-C20 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiophenyl, benzodibenzofuranyl, benzodibenzothiophenyl, dinaphthofuranyl and dinaphthothiophenyl; The C6-C20 aryl group is selected from any one of phenyl, biphenyl and naphthyl.

6. The oxygen-containing heterocyclic compound according to claim 1, characterized in that The hydrogen atoms in the formula BH-A may be independently substituted by any one of -D, methyl, ethyl, propyl, butyl, pentyl, hexyl, methoxy, ethoxy, propoxy, phenyl, naphthyl, dibenzothienyl, and dibenzofuranyl.

7. The oxygen-containing heterocyclic compound according to claim 1, characterized in that The oxygen-containing heterocyclic compound is selected from any one of the following compounds:

8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode; The material of the organic thin film layer includes the oxygen-containing heterocyclic compound according to any one of claims 1 to 6.

9. The organic electroluminescent device according to claim 8, characterized in that: The organic thin film layer includes a light-emitting layer, and the material of the light-emitting layer includes the oxygen-containing heterocyclic compound; Preferably, the material of the light-emitting layer includes a host material and a doping material, and the host material includes the oxygen-containing heterocyclic compound.

10. A display device, characterized in that: The display device comprises the organic electroluminescent device according to claim 8 or 9.

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