A compound, an organic electroluminescence device, and a display device

Abstract

The application provides a compound, an organic electroluminescent device and a display device, and relates to the technical field of organic optoelectronics.The compound provided by the application can increase the electron transport capacity of a device, reduce an electron injection and transport potential barrier, and can be used for preparing an organic electroluminescent device, in particular, as an electron transport layer material in the organic electroluminescent device, so that the driving voltage of the organic electroluminescent device can be effectively reduced, the current efficiency can be improved, and the service life can be prolonged.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic technology, specifically relating to a compound, an organic electroluminescent device, and a display device. Background Technology

[0002] Organic light-emitting diode (OLED) materials have significant research value and promising application prospects in fields such as information display materials and organic optoelectronic materials. With the development of multimedia information technology, the performance requirements for flat panel display devices are becoming increasingly stringent. Currently, the main display technologies include plasma display devices, field emission display devices, and organic light-emitting diode (OLED) devices. Among them, OLEDs possess a series of advantages such as self-illumination, low-voltage DC drive, all-solid-state operation, wide viewing angle, and rich colors. Compared with liquid crystal displays (LCDs), OLEDs do not require a backlight, have a wider viewing angle, lower power consumption, and a response speed 1000 times faster than LCDs. Therefore, OLEDs have a broader application prospect.

[0003] As OLED products gradually enter the market, people have increasingly higher requirements for their performance. The selection of materials for the hole layer, emissive layer, and other organic functional layers has a significant impact on the current efficiency, driving voltage, and lifetime of the device. Currently, the exploration of functional layer materials with higher performance is still ongoing. Therefore, in order to meet people's higher requirements for OLED devices, there is an urgent need in this field to develop more types and higher performance OLED materials. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a compound, an organic electroluminescent device, and a display device. The compound can be used as an electron transport material in OLED devices, and the resulting organic electroluminescent device exhibits lower driving voltage, higher current efficiency, and longer lifespan.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] In a first aspect, the present invention provides a compound having a structure as shown in Formula I:

[0007]

[0008] In Formula I, R1 and R2 are each independently selected from any one of substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl groups; the substituents are selected from any one of D, F, cyano, C1-C6 alkyl, phenyl, and carbazole.

[0009] Ar1 is selected from any one of single bonds and C6~C30 arylene groups.

[0010] The compounds provided by this invention, through specific structural design, can increase the electron transport capability of devices, reduce the electron injection transport barrier, and reduce the driving voltage, thereby improving the luminous efficiency of devices and exhibiting good luminous performance. They can be used to prepare organic electroluminescent devices, especially as electron transport layer materials in organic electroluminescent devices, which can effectively reduce the driving voltage of organic electroluminescent devices and improve the current efficiency of organic electroluminescent devices.

[0011] Preferably, the C6-C30 aryl group is selected from any one of phenyl, biphenyl, naphthyl, fluorenyl, phenanthryl, anthracene, fluoranyl, and triphenylene.

[0012] Preferably, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiazolyl, and carbazoleyl.

[0013] Preferably, the C6-C30 arylene group is selected from any one of phenylene, naphthylene, and biphenylene.

[0014] Preferably, the C1-C6 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, and hexyl.

[0015] Preferably, R1 and R2 are each independently selected from phenyl, biphenyl, naphthyl, 9,9-dimethylfluorenyl, phenanthrene, fluoranyl, triphenylene, and other phenyl groups. , Any one of dibenzofuranyl, dibenzothiazolyl, carbazole, N-phenylcarbazole, or carbazole-substituted phenyl.

[0016] Preferably, Ar1 is selected from any one of single bond, phenylene, naphthylene, and biphenylene.

[0017] Preferably, the compound is selected from any one of the following compounds:

[0018]

[0019] .

[0020] Preferably, the compound is selected from any one of compounds 1 to 12:

[0021] .

[0022] In a second aspect, the present invention provides an organic electroluminescent device, the organic electroluminescent device comprising the compounds described in the first aspect.

[0023] Preferably, the organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode; the material of the organic layer includes the aforementioned compound.

[0024] Preferably, the organic layer includes an electron transport layer; the material of the electron transport layer includes the aforementioned compound.

[0025] Preferably, the organic layer further includes a light-emitting layer, which comprises a host material and a dopant material.

[0026] In this invention, no special restrictions are placed on the main material and doping material of the light-emitting layer; any known main material and doping material of the light-emitting layer in the art can be used.

[0027] In this invention, the main material of the light-emitting layer can be a single compound or a mixture formed by two or more compounds.

[0028] In this invention, the volume percentage of the main material in the light-emitting layer is 60% to 99.9% (for example, it can be 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99.9%), preferably 70% to 99.5%, and more preferably 88% to 98%.

[0029] Preferably, the organic layer further includes at least one of a hole transport layer, a hole injection layer, an electron blocking layer, an electron injection layer, and a hole blocking layer. In this invention, no special limitations are placed on the materials used for the hole transport layer, hole injection layer, electron blocking layer, electron injection layer, and hole blocking layer; any materials known in the art capable of hole injection, hole transport, electron blocking, electron injection, and hole blocking can be used.

[0030] Thirdly, the present invention provides a display device comprising the organic electroluminescent device as described in the second aspect.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The compounds provided by this invention, through specific structural design, can increase the electron transport capability of devices, reduce the electron injection transport barrier, and reduce the driving voltage, thereby improving the luminous efficiency of devices and exhibiting good luminous performance. They can be used to prepare organic electroluminescent devices, especially as electron transport layer materials in organic electroluminescent devices, which can effectively reduce the driving voltage of organic electroluminescent devices and improve the current efficiency of organic electroluminescent devices. Detailed Implementation

[0033] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0034] Synthesis Example 1

[0035] This embodiment provides a method for synthesizing compound 1, and the synthetic route of compound 1 is as follows:

[0036]

[0037] Synthesis of Intermediate I

[0038] Under nitrogen protection, 40.0 mmol of starter A, 44.0 mmol of starter B, 500 ml of toluene, and 200 ml of water were added to a reaction flask. Then, 60.0 mmol of potassium carbonate and 0.8 mmol of tetraphenylphosphine palladium were added. The mixture was heated to reflux and stirred for 12 h. After the reaction was complete, 400 ml of water was added to the reaction solution, and the mixture was stirred for 30 min. The mixture was separated, and the organic phase was washed twice with 300 ml of water. The organic phase was concentrated to 100 ml, and 200 ml of ethanol was added. The mixture was stirred for 30 min, filtered, and the filter cake was recrystallized from the filter cake using a mixed solvent of toluene and ethanol to obtain intermediate I.

[0039] Intermediate I was analyzed by mass spectrometry, and the m / z was 399.07.

[0040] Synthesis of Intermediate II

[0041] Under an inert atmosphere, 30 mmol of intermediate I, 150 mmol of potassium carbonate, and 200 mL of dimethylacetamide were added to a reaction flask and stirred for 30 min. Then, 1.50 mmol of palladium acetate and 3.00 mmol of 1,3-bis(2,6-diisopropylphenyl)chloroimidazolam were added, and the mixture was stirred at 145 °C for 24 h. After the reaction was completed, the mixture was cooled, and 150 mL of dimethylacetamide was distilled off by vacuum distillation. The mixture was then extracted with 300 mL of toluene and 300 mL of water. The aqueous phase was extracted twice with 250 mL of toluene. The organic phases were combined and washed twice with 300 mL of water and twice with 150 mL of saturated NaCl solution. The mixture was dried with Na2SO4, filtered, and the filtrate was concentrated by rotary evaporation to obtain the crude product. 200 mL of n-heptane was added to the crude product, and the mixture was stirred at room temperature for 30 min. The mixture was then filtered, and the filter cake was washed with n-heptane and dried in a vacuum drying oven to obtain intermediate II.

[0042] Intermediate II was detected by mass spectrometry, and the m / z was 363.09.

[0043] Synthesis of Intermediate III

[0044] 25 mmol of intermediate II was added to 100 mL of ethanol and hydrogenated for 36 h at 3 kPa hydrogen pressure using 1 g of palladium / carbon catalyst. The mixture was then filtered twice using a Buchner funnel, and the filtrate was concentrated by rotary evaporation. The resulting solid was recrystallized from toluene to obtain intermediate III.

[0045] Intermediate III was detected by mass spectrometry, and the m / z was 333.12.

[0046] Synthesis of intermediate IV

[0047] Add 10.0 mmol of intermediate III, 20.0 mmol of neopentanoic acid, 2.2 mmol of Cu(OAc)2, 0.43 mmol of dichloro(pentamethylcyclopentadienyl)iridium(III) dimer and 100 ml of NMP (N-methylpyrrolidone) to a flask. Under nitrogen protection, stir the mixture at 120 °C for 50 min. After the reaction is complete, cool the mixture, remove NMP by distillation, and further purify the residue by column chromatography to obtain intermediate IV.

[0048] Intermediate IV was detected by mass spectrometry, and the m / z was 331.10.

[0049] Synthesis of Compound 1

[0050] Under nitrogen protection, 10.0 mmol of intermediate IV, 12.0 mmol of starting material C, 0.2 mmol of tris(dibenzylacetone)dipalladium, 0.4 mmol of 2-dicyclohexylphosphine-2',4',6'-triisopropylbiphenyl, 15 mmol of sodium tert-butoxide, and 300 ml of xylene were added to the reaction flask. The mixture was heated to reflux and stirred for 12 h. After cooling to room temperature, 400 ml of ethanol was added to the reaction solution, and the mixture was stirred for 30 min. The mixture was then filtered, and the filter cake was washed twice with 300 ml of water. The filter cake was then filtered again and recrystallized from the filter cake using a mixed solvent of toluene and ethanol to obtain compound 1.

[0051] Compound 1 was analyzed by mass spectrometry, and the m / z was 562.18.

[0052] Following the synthetic method described above, the compounds shown in Table 1 were prepared. The only difference from compound 1 was that starting material C was replaced with other triazine compounds (see Table 1), while all other conditions remained unchanged:

[0053] Table 1

[0054]

[0055]

[0056]

[0057]

[0058] For other compounds whose specific synthesis methods are not listed, they can be synthesized by referring to the above examples and combining them with common knowledge in the field.

[0059] The specific structures of some of the materials used in the following device embodiments and device comparison examples are as follows:

[0060]

[0061] The device embodiments use compounds from this application as electron transport materials in organic electroluminescent devices, while the device comparative examples use E1 to E3 as electron transport materials in organic electroluminescent devices.

[0062] Device Example 1

[0063] The structure of the organic electroluminescent device is: ITO / HT (40nm) / BH-1:BD-1 3% (30nm) / Compound 1 (30nm) / LiF (0.5nm) / Al (150nm).

[0064] The fabrication method of the above-mentioned organic electroluminescent device is as follows:

[0065] The glass substrate coated with an ITO transparent conductive layer (as the anode) was ultrasonically treated in a cleaning agent, then rinsed in deionized water, then ultrasonically degreased in a mixed solvent of acetone and ethanol, then baked in a clean environment until completely dehydrated, cleaned with ultraviolet light and ozone, and bombarded with a low-energy cation beam to improve the surface properties and enhance the binding ability with the hole transport layer.

[0066] The glass substrate was placed in a vacuum chamber and evacuated to a vacuum level of 1×10⁻⁶. -5 ~9×10 -3 Pa, HT is vacuum-deposited on the anode as a hole transport layer at a deposition rate of 0.1 nm / s and a film thickness of 40 nm;

[0067] A light-emitting layer was vacuum-deposited on top of the hole transport layer at a deposition rate of 0.1 nm / s and a film thickness of 30 nm. The main material of the light-emitting layer was BH-1, and the doping material was BD-1. The 3% refers to the doping ratio of the doping material, that is, the volume ratio of the main material of the light-emitting layer to the doping material is 97:3.

[0068] Compound 1 was vacuum-deposited as an electron transport layer on top of the luminescent layer at a deposition rate of 0.1 nm / s, resulting in a film thickness of 30 nm. 0.5 nm of LiF and 150 nm of Al were then vacuum-deposited on the electron transport layer as an electron injection layer and a cathode, respectively. The brightness, driving voltage, current efficiency, and lifetime of the fabricated organic electroluminescent device were measured.

[0069] Device Examples 2-12

[0070] Device Examples 2-12 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the electron transport material is different (see Table 2 below), while other conditions are the same as those in Device Example 1.

[0071] Device Comparison Examples 1-3

[0072] Comparative Examples 1 to 3 each provide an organic electroluminescent device, which differs from Device Example 1 only in that the electron transport material is different (see Table 2 below), while other conditions are the same as Device Example 1.

[0073] Performance testing

[0074] Test Method: The driving voltage, current efficiency, and lifetime LT90 of the OLED devices provided above were tested. LT90 refers to the time required for the brightness to decrease to 90% of its original brightness while maintaining an initial brightness of 1000 nits at a constant current density. Test items included the brightness, driving voltage, current efficiency, and lifetime LT90 of the organic light-emitting diode. The driving voltage, current efficiency, and LT90 data were all based on a brightness of 1000 cd / m². 2 The relative values ​​at different times (based on Comparative Example 1). The performance test results of the organic electroluminescent devices are shown in Table 2 below:

[0075] Table 2

[0076]

[0077] As shown in Table 2, the compounds obtained by this invention through molecular design can be used as electron transport materials for OLED light-emitting devices, enabling OLED light-emitting devices to have lower driving voltage, higher current efficiency, and longer lifespan.

[0078] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, 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 improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A compound, characterized in that, The compound has the structure shown in Formula I: In Formula I, R1 and R2 are each independently selected from any one of substituted or unsubstituted C6-C30 aryl and substituted or unsubstituted C6-C30 heteroaryl groups; the substituents are selected from any one of D, F, cyano, C1-C6 alkyl, phenyl, and carbazole. Ar1 is selected from any one of single bonds and C6~C30 arylene groups.

2. The compound according to claim 1, characterized in that, The C6-C30 aryl group is selected from any one of phenyl, biphenyl, naphthyl, fluorenyl, phenanthryl, anthracene, fluoranyl, and triphenylene. Preferably, the C6-C30 heteroaryl group is selected from any one of dibenzofuranyl, dibenzothiazolyl, and carbazoleyl; Preferably, the C6-C30 arylene group is selected from any one of phenylene, naphthylene, and biphenylene; Preferably, the C1-C6 alkyl group is selected from any one of methyl, ethyl, propyl, butyl, pentyl, and hexyl.

3. The compound according to claim 1, characterized in that, R1 and R2 are each independently selected from phenyl, biphenyl, naphthyl, 9,9-dimethylfluorenyl, phenanthrene, fluoranyl, triphenylene, and other compounds. , Any one of dibenzofuranyl, dibenzothiazolyl, carbazole, N-phenylcarbazole, or carbazole-substituted phenyl.

4. The compound according to claim 1, characterized in that, The Ar1 is selected from any one of single bonds, phenylene, naphthylene, and biphenylene.

5. The compound according to claim 1, characterized in that, The compound is selected from any one of the following compounds: 。 6. The compound according to claim 1, characterized in that, The compound is selected from any one of the following compounds 1 to 12: 。 7. An organic electroluminescent device, characterized in that, The organic electroluminescent device includes the compound as described in any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that, The organic electroluminescent device includes a first electrode, a second electrode, and an organic layer disposed between the first electrode and the second electrode; the material of the organic layer includes the aforementioned compound.

9. The organic electroluminescent device according to claim 8, characterized in that, The organic layer includes an electron transport layer; the material of the electron transport layer includes the aforementioned compound.

10. A display device, characterized in that, The display device includes an organic electroluminescent device as described in any one of claims 7 to 9.

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