Heterocyclic compound containing boron and nitrogen, organic electroluminescent device and display device

Abstract

The invention provides a heterocyclic compound containing boron and nitrogen, an organic electroluminescent device and a display device, and relates to the technical field of organic photoelectric display. By designing the structure of the heterocyclic compound containing boron and nitrogen, the obtained heterocyclic compound containing boron and nitrogen has excellent performance, and the organic electroluminescent device prepared by using the heterocyclic compound containing boron and nitrogen as a luminescent layer material has relatively low driving voltage and relatively high current efficiency.

Description

Technical Field

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

[0002] An organic light emitting element (organic light emitting diode; OLED) is a display component that utilizes the self-luminous phenomenon. It has a large viewing angle. Compared with liquid crystal display components, OLED components are thinner, lighter, have a faster response speed, and can achieve flexible display. Therefore, it is highly anticipated as an application for full-color display components or lighting devices.

[0003] Generally, the organic light emitting phenomenon refers to the phenomenon of converting electrical energy into light energy using organic substances. An organic light emitting element utilizing the organic light emitting phenomenon usually has a structure including an anode, a cathode, and an organic layer sandwiched between the anode and the cathode.

[0004] Among them, in order to improve the efficiency and stability of the organic light emitting element, the organic layer is mostly composed of a multi-layer structure formed by different substances respectively. For example, it can be composed of a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, etc. If a voltage is applied between the two electrodes in the structure of such an organic light emitting element, holes in the anode will be injected into the organic layer, and electrons in the cathode will also be injected into the organic layer. When the injected holes and electrons meet, excitons are formed. When the excitons release energy and transition to the ground state, photons will be emitted, thereby generating light. Such an organic light emitting element is widely recognized as having characteristics such as self-luminescence, high brightness, high efficiency, low driving voltage, wide viewing angle, high contrast, and high-speed responsiveness.

[0005] Currently, the research on organic electroluminescent materials has been widely carried out in the academic and industrial fields. Among them, the light emitting layer material is an important part of the organic electroluminescent device, and its transport performance and light emitting efficiency restrict the industrialization of the light emitting device. Therefore, designing and finding a compound that can be used as an OLED light emitting layer material to overcome the deficiencies that occur in the actual application process is the focus and future research and development trend in the research work of OLED materials. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a boron-nitrogen-containing heterocyclic compound and its application. Through the design of the structure of the boron-nitrogen-containing heterocyclic compound, the obtained boron-nitrogen-containing heterocyclic compound has excellent properties and is suitable for use as a light emitting layer material in organic electroluminescent devices.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a boron-nitrogen-containing heterocyclic compound having a structure represented by Formula I or Formula II:

[0009]

[0010] In Formula I and Formula II, R 1 , R 2 , R 3 , R 4 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C 1 -C 12 alkyl, substituted or unsubstituted C 6 -C 30 aryl, or substituted or unsubstituted C 3 -C 30 heteroaryl, and R 1 , R 2 , R 3 , R 4 are the same or different; and at least one of R 1 , R 2 , R 3 , R 4 has a structure represented by Formula A:

[0011]

[0012] The * in Formula A represents the connection site;

[0013] In Formula I and Formula II, X is selected from oxygen or sulfur;

[0014] The substituents of the substitution are selected from deuterium, F, cyano, C 1 -C 12 alkyl, C 6 -C 30 aryl or C 3 -C 30 heteroaryl;

[0015] The hydrogen atoms in Formula I and Formula II can each independently be substituted by deuterium, F, cyano, C 1 -C 12 alkyl, C 6 -C 30 aryl or C 3 -C 30 heteroaryl.

[0016] Preferably, the C 1 -C 12 alkyl is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, pivalyl, n-hexyl or cyclohexyl.

[0017] More preferably, the C 1 ~C 12 alkyl group is selected from methyl, ethyl, isopropyl or tert-butyl.

[0018] In the present invention, aryl refers to the general name of a monovalent group remaining after removing a hydrogen atom from the aromatic nucleus carbon of an aromatic hydrocarbon molecule; the aryl includes monocyclic aryl or polycyclic aryl.

[0019] Preferably, the C 6 ~C 30 aryl group is selected from phenyl, biphenyl, terphenyl, naphthyl, anthryl, indenyl, perylenyl, phenanthryl, pyrenyl, fluoranthenyl, fluorenyl, spirobifluorenyl or benzophenanthryl.

[0020] More preferably, the C 6 ~C 30 aryl group is selected from phenyl, biphenyl and naphthyl.

[0021] In the present invention, heteroaryl refers to the general name of a group obtained by replacing one or more aromatic nucleus carbons in aryl with heteroatoms; the heteroaryl includes monocyclic heteroaryl or polycyclic heteroaryl.

[0022] Preferably, the heteroatom of the C 3 ~C 30 heteroaryl group is selected from oxygen, sulfur, nitrogen or silicon.

[0023] Preferably, the C 3 ~C 30 heteroaryl group is selected from pyridyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, diarylamino, benzofurano[3,2-b]carbazolyl, benzofurano[3,2-b]thiophenyl or triazinyl.

[0024] More preferably, the C 3 ~C 30 heteroaryl group is selected from pyridyl, dibenzofuranyl, dibenzothiophenyl or carbazolyl. Preferably, the boron-nitrogen-containing heterocyclic compound is selected from any one of Compounds 1 to 32:

[0025]

[0026]

[0027] Some specific structural forms of the boron-nitrogen-containing heterocyclic compound are listed in the present invention, but the boron-nitrogen-containing heterocyclic compound described in the present invention is not limited to these listed chemical structures. Any structure based on the structures shown in Formula I or Formula II, where R 1 、R 2 、R 3 、R 4 、X meet the above-defined conditions should be included.

[0028] In a second aspect, the present invention provides an organic electroluminescent device, which includes a boron-nitrogen-containing heterocyclic compound as described in the first aspect.

[0029] 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;

[0030] The organic layer includes a boron-nitrogen-containing heterocyclic compound as described in the first aspect.

[0031] Preferably, the organic layer includes a light-emitting layer;

[0032] The light-emitting layer includes a boron-nitrogen-containing heterocyclic compound as described in the first aspect.

[0033] Furthermore, the light-emitting layer is prepared by a vapor deposition method.

[0034] Preferably, the light-emitting layer includes a host material and a doping material;

[0035] The doping material includes a boron-nitrogen-containing heterocyclic compound as described in the first aspect.

[0036] In a third aspect, the present invention provides a display device, which includes the organic electroluminescent device as described in the second aspect.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] By designing the structure of the boron-nitrogen-containing heterocyclic compound, the obtained boron-nitrogen-containing heterocyclic compound has good light-emitting properties and can be used to prepare an organic electroluminescent device. As a light-emitting layer material in the organic electroluminescent device, especially the doping material of the light-emitting layer can effectively reduce the driving voltage of the organic electroluminescent device and improve the current efficiency of the organic electroluminescent device. Specific Embodiments

[0039] To facilitate the understanding of the present invention, preparation examples and embodiments are listed as follows. Those skilled in the art should understand that the preparation examples and embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0040] Synthesis Example 1

[0041] This embodiment provides a synthesis method of Compound 1, and the synthesis method is as follows:

[0042]

[0043] (1) Synthesis of Intermediate 1-1

[0044] Under nitrogen protection, add 200 mL of dried toluene, 0.1 mol of silicon halide-1, 0.1 mol of diphenylamine, and 0.001 mol of Pd(dba) into a 500 mL three-necked flask. 2 (bis(dibenzylideneacetone palladium), 4g of a 10% tri-tert-butylphosphine toluene solution (containing 0.002mol tri-tert-butylphosphine) and 0.3mol sodium tert-butoxide, heated to reflux for 12h, cooled to room temperature, added water to separate, then the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, and crystallized with ethanol to obtain intermediate 1-1;

[0045] The mass spectrometry of intermediate 1-1 revealed a mass-to-charge ratio (m / z) of 555.2.

[0046] (2) Synthesis of intermediate 1-2

[0047] Under nitrogen protection, 200 mL of DMF, 0.1 mol of intermediate 1-1, 0.15 mol of phenol, 0.01 mol of cuprous iodide, 0.05 mol of tetramethylethylenediamine and 0.25 mol of cesium carbonate were added to a 500 mL three-necked flask, heated to 130 ° C for reaction for 24 h, cooled to room temperature, and separated by adding water. The organic layer was then washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, dissolved with toluene, and subjected to column chromatography. The resulting chromatographic solution was concentrated to dryness and then recrystallized with toluene to obtain intermediate 1-2.

[0048] The obtained intermediate 1-2 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 629.2.

[0049] (3) Synthesis of Compound 1

[0050] Under nitrogen protection, the reaction bottle containing 0.01mol intermediate 1-2 and 100ml toluene was cooled to 0°C, and then a pentane solution of tert-butyl lithium (containing 0.3mol tert-butyl lithium) with a concentration of 1.7M was added dropwise to the reaction system. After the addition was completed, the temperature was raised to 70°C and stirred for 3h. Then the system was cooled to -40°C, 0.012mol boron tribromide was added dropwise, and after the addition was completed, the temperature was raised to 25°C and stirred for 4h. After the reaction was completed, saturated Na2S2O3 aqueous solution and saturated NaHCO3 aqueous solution were added dropwise to the reaction system. After separation, the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a mixed solvent of n-heptane and dichloromethane (the volume ratio of n-heptane to dichloromethane was 2:1) to obtain compound 1.

[0051] The obtained compound 1 was subjected to mass spectrometry detection, and the mass-to-charge ratio (m / z) was measured to be 603.2.

[0052] Synthesis Example 2

[0053] This example provides a method for synthesizing Compound 2, and the synthesis method is as follows:

[0054]

[0055] Referring to the synthesis method of Synthesis Example 1, replacing diphenylamine in Synthesis Example 1 with an equimolar amount of carbazole, and keeping other conditions unchanged, Compound 2 can be obtained.

[0056] The obtained Compound 2 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 601.2.

[0057] Synthesis Example 3

[0058] This example provides a method for synthesizing Compound 3, and the synthesis method is as follows:

[0059]

[0060] Referring to the synthesis method of Synthesis Example 1, replacing phenol in Synthesis Example 1 with thiophenol, and keeping other conditions unchanged, Compound 3 can be obtained.

[0061] Compound 3 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z): 619.2.

[0062] Synthesis Example 4

[0063] This synthesis example provides a method for synthesizing Compound 5, and the synthesis method is as follows:

[0064]

[0065] (1) Synthesis of Intermediate 5-1

[0066] Under nitrogen protection, 500 mL of dried DMF, 0.1 mol of fluorochloride-1, 0.11 mol of 3-triphenylsilylphenol, 0.01 mol of cuprous iodide, 0.05 mol of tetramethylethylenediamine, and 0.25 mol of cesium carbonate were added to a 500 mL three-necked flask, heated to 130 °C and reacted for 24 h, then cooled to room temperature, water was added for liquid separation, and then the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, dissolved in toluene and subjected to column chromatography. After the obtained chromatography solution was concentrated to dryness, it was recrystallized with toluene to obtain Intermediate 5-1;

[0067] The obtained Intermediate 5-1 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 629.2.

[0068] (2) Synthesis of Compound 5

[0069] Under nitrogen protection, the reaction flask containing 0.01 mol of intermediate 5-1 and 100 ml of toluene was cooled to 0 °C, and then a pentane solution of tert-butyllithium with a concentration of 1.7 M (containing 0.3 mol of tert-butyllithium) was added dropwise to the reaction system. After the addition was complete, the temperature was raised to 70 °C and stirred for 3 h. Then the system was cooled to -40 °C, and 0.012 mol of boron tribromide was added dropwise. After the addition was complete, the temperature was raised to 25 °C and stirred for 4 h. After the reaction was completed, saturated Na 2 S 2 O 3 aqueous solution and saturated NaHCO 3 aqueous solution were added. After liquid separation, the organic layer was washed with water until neutral, dried with magnesium sulfate, filtered to remove magnesium sulfate, concentrated to dryness, separated by silica gel column chromatography, and eluted with a mixed solvent of n-heptane and dichloromethane (the volume ratio of n-heptane to dichloromethane was 2:1) to obtain compound 5.

[0070] The obtained compound 5 was subjected to mass spectrometry detection, and the measured mass-to-charge ratio (m / z) was 603.2.

[0071] Referring to the synthesis method of the above compounds and combining common organic synthesis means, compounds 4, 7, 8, 18, 20, and 25 were prepared and subjected to mass spectrometry detection. The test results are shown in Table 1 below.

[0072] Table 1

[0073]

[0074]

[0075] Other compounds for which the specific synthesis steps are not listed can be prepared by combining the common general knowledge in the art with the above examples.

[0076] The specific structures of some compounds used in the following device examples and device comparative examples are shown below:

[0077]

[0078] In the following device examples, the boron-nitrogen-containing heterocyclic compound provided by the present invention was selected as the luminescent layer doping material in the organic electroluminescent device, and in the device comparative examples, the above BD-1 and BD-2 were selected as the luminescent layer doping materials in the organic electroluminescent device.

[0079] Device Example 1

[0080] This device example provides an organic electroluminescent device using compound 1 provided by the synthesis example 1 of the present invention as the luminescent layer doping material; and in this example, the luminescent layer was prepared by evaporation.

[0081] The structure of the organic electroluminescent device is as follows:

[0082] ITO / HT (40 nm) / BH: Compound 13% / TPBI (30 nm) / LiF (0.5 nm) / Al (150 nm).

[0083] The preparation method of the above organic electroluminescent device is as follows:

[0084] 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 injection layer;

[0085] The above glass substrate is placed in a vacuum chamber, evacuated to 1×10 -5 ~9×10Pa, and HT is vacuum-evaporated on the anode as the hole transport layer at a deposition rate of 0.1 nm / s, and the deposited film thickness is 40 nm;

[0086] The light-emitting layer is vacuum-evaporated on the hole transport layer at a deposition rate of 0.1 nm / s, and the deposited film thickness is 30 nm. The host material of the light-emitting layer is BH, and the doping material is Compound 1 provided by the present invention. 3% refers to the doping ratio of the doping material, that is, the volume ratio of the host material to the doping material in the light-emitting layer is 97:3.

[0087] The glass substrate on which the light-emitting layer has been deposited in the previous step is transferred to the vacuum chamber, and TPBI is vacuum-evaporated on the light-emitting layer as the electron transport layer of the device at a deposition rate of 0.1 nm / s, and the deposited film thickness is 30 nm;

[0088] 0.5 nm of LiF and 150 nm of Al are vacuum-evaporated on the electron transport layer as the electron injection layer and the cathode.

[0089] The brightness, driving voltage, and current efficiency of the prepared organic electroluminescent device were measured.

[0090] Device Examples 2 to 12

[0091] Device Examples 2 to 12 respectively provide an organic electroluminescent device, which is only different from Device Example 1 in that the doping material of the light-emitting layer is different (see Table 2 for details), and other conditions are the same as those in Device Example 1.

[0092] Device Comparative Examples 1 to 2

[0093] Device Comparative Examples 1-2 respectively provide an organic electroluminescent device, which is different from Device Example 1 only in that the doping material of the light-emitting layer is different (see Table 2 for details), and other conditions are the same as those of Device Example 1.

[0094] Performance Test

[0095] Test the driving voltage, current efficiency and lifetime LT90 of the above-provided OLED devices; 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 driving voltage, current efficiency, and LT90 data are all relative values at a brightness of 1000 cd / m 2 (based on the test data of BD-1). The performance test results of the organic electroluminescent device are shown in Table 2 below.

[0096] Table 2

[0097] Doping material <![CDATA[Required luminance / (cd / m 2 )]]> Driving voltage Current efficiency LT90 life Device Comparative Example 1 BD-1 1000 1 1 1 Device Comparative Example 2 BD-2 1000 1.12 1.05 0.96 Device Example 1 Compound 1 1000 0.82 1.21 1.57 Device Example 2 Compound 2 1000 0.79 1.26 1.44 Device Example 3 Compound 3 1000 0.76 1.29 1.46 Device Example 4 Compound 4 1000 0.75 1.27 1.59 Device Example 5 Compound 5 1000 0.73 1.28 1.51 Device Example 6 Compound 7 1000 0.77 1.26 1.56 Device Example 7 Compound 8 1000 0.77 1.28 1.49 Device Example 8 Compound 18 1000 0.81 1.33 1.51 Device Example 9 Compound 20 1000 0.75 1.28 1.61 Device Example 10 Compound 25 1000 0.76 1.32 1.55

[0098] As can be seen from the above, through structural design, the present invention obtains a compound suitable as a doping material for the light-emitting layer. The organic electroluminescent device prepared therefrom has a lower driving voltage, a higher current efficiency, and a longer service life.

[0099] 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. A boron-nitrogen-containing heterocyclic compound, characterized in that: The boron-nitrogen-containing heterocyclic compound has a structure as shown in Formula I or Formula II: In Formula I and Formula II, R1, R2, R3, and R4 are each independently selected from hydrogen, deuterium, substituted or unsubstituted C1 to C 12 Alkyl, substituted or unsubstituted C6~C 30 Aryl, substituted or unsubstituted C3~C 30 Heteroaryl, R1, R2, R3, R4 are the same or different; and at least one of R1, R2, R3, R4 is a structure represented by formula A: The * in formula A represents the attachment site; In formula I and formula II, X is selected from oxygen or sulfur; The substituted substituent is selected from deuterium, F, cyano, C1-C 12 Alkyl, C6~C 30 Aryl or C3~C 30 heteroaryl; The hydrogen atoms in formula I and formula II can be independently replaced by deuterium, F, cyano, C1-C 12 Alkyl, C6~C 30 Aryl or C3~C 30 Heteroaryl substitution.

2. The boron-nitrogen-containing heterocyclic compound according to claim 1, characterized in that C1~C 12 The alkyl group is selected from methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, tert-pentyl, n-hexyl or cyclohexyl.

3. The boron-nitrogen-containing heterocyclic compound according to claim 1, characterized in that C6~C 30 Aryl is selected from phenyl, biphenyl, terphenyl, naphthyl, anthracenyl, indenyl, fluorenyl, perylenyl, phenanthrenyl, pyrenyl, fluoranthenyl, spirobifluorenyl or triphenylenyl.

4. The boron-nitrogen-containing heterocyclic compound according to claim 1, characterized in that C3~C 30 The heteroatoms in the heteroaryl group are selected from oxygen, sulfur, nitrogen or silicon.

5. The boron-nitrogen-containing heterocyclic compound according to claim 1, characterized in that C3~C 30 The heteroaryl group is selected from benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, carbazolyl, diarylideneamine, benzofuranocarbazolyl, benzofuranothiophenyl or triazine.

6. The boron-nitrogen-containing heterocyclic compound according to claim 1, characterized in that The boron-nitrogen-containing heterocyclic compound is selected from any one of compounds 1 to 32:

7. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises the boron-nitrogen-containing heterocyclic compound according to any one of claims 1 to 6.

8. The organic electroluminescent device according to claim 7, characterized in that: The organic electroluminescent device comprises a first electrode, a second electrode and an organic layer arranged between the first electrode and the second electrode; the organic layer comprises a light-emitting layer; and the light-emitting layer comprises the heterocyclic compound containing boron and nitrogen.

9. The organic electroluminescent device according to claim 8, characterized in that: The light-emitting layer includes a main material and a doping material, and the doping material includes the boron-nitrogen-containing heterocyclic compound.

10. A display device, characterized in that: The display device comprises the organic electroluminescent device according to any one of claims 7 to 9.

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