TW201827400A - Hole Transfer Compound and Organic Light-Emitting Diodes Using the Same - Google Patents

Abstract

The present invention relates to hole transfer compounds having the structure of (formula 1) and organic light-emitting diodes using the same.

Description

Hole transporting compound and organic light emitting element containing the same

The present invention relates to a hole-transporting compound and an organic light-emitting device containing the hole-transporting compound. Further, based on a high hole-transport characteristic, the allylamino group is introduced into a carbazole having a relatively low free potential characteristic. The ring core is used to reduce the formation of crystals, reduce the free potential, and improve the hole transporting ability, so that it has hole-transporting compounds with the characteristics of increasing service life and organic light-emitting elements containing the hole-transporting compounds.

An electroluminescent device (EL element) is a self-luminous display element. In addition to a wide viewing angle and high contrast, it has the advantage of fast response time.

EL elements are divided into inorganic EL elements and organic EL elements according to the constituent materials of the emitting layer. Compared with inorganic EL elements, organic EL elements have better brightness, driving voltage, and response speed than inorganic elements, and they have the advantage of being colorful.

A general organic EL element has a structure in which an anode is disposed above a substrate, and a hole transporting layer, a light emitting layer, an electron transporting layer, and a cathode are arranged above the anode in this order. Here, the hole transport layer, the light emitting layer, and the electron transport layer are organic thin films formed of an organic compound.

The driving principle of the organic EL element having the aforementioned structure is as follows. When a voltage is applied between the anode and the cathode, the hole injected from the anode moves to the light emitting layer through the hole transport layer. On the other hand, electrons are injected from the cathode through the electron-transporting layer into the light-emitting layer, and carriers are recombined in the light-emitting layer region to generate excitons. The exciton changes from an excited state to a ground state, and the molecules of the light emitting layer emit light to generate a picture. According to the mechanical rotation, the luminescent material is divided into a fluorescent material using a singlet exciton and a phosphorescent material in a triplet state.

Until now, there have been many studies on amino derivatives with allylamino skeletons used in such organic light-emitting devices as hole transport materials, but because they require a higher driving voltage, and have low efficiency and short service life. Therefore, there are many difficulties in practical application.

Therefore, researchers are devoted to the development of substances with excellent characteristics to realize organic light-emitting devices with low voltage driving, high luminance, and long service life.

Prior Art Document: Patent Document 1: Republic of Korea Registered Patent Gazette No. 10-1631507.

The problem to be solved by the present invention: The problem to be solved by the present invention is to provide an allylamino group to a carbazole ring core having a relatively low free potential characteristic based on a high hole transport characteristic to reduce crystal formation, A hole transporting compound and an organic light-emitting element containing the same can be used to reduce the free potential and improve the hole transporting ability, so that the hole transporting compound has the characteristics of increasing the service life.

Means for Solving the Problem: In order to solve the above-mentioned problem, the present invention provides a hole-transporting compound represented by the following <Chemical Formula 1>.

＜ Chemical Formula 1 ＞

In the above chemical formula, the R1 and R2 are independent of each other, and may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, a substituted or unsubstituted C1-C14 alkyl group Oxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C1 allylalkyl, substituted or unsubstituted C6-C14 allyl Oxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allyl carboxyl, or C1-C14 An alkylthio group, and the above heterocyclic ring contains one or more heterocyclic atoms selected from nitrogen (N), oxygen (O), and sulfur (S).

In order to solve the above problems, the present invention provides a hole transporting compound represented by the following <Chemical Formula 4>.

＜ Chemical Formula 4 ＞

In the above chemical formula, the above-mentioned R1 and R2 are each independently, which may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, or a substituted or unsubstituted C1-C14 Alkoxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C14 allylalkyl, substituted or unsubstituted C6-C14 ene Propoxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allylcarboxyl, or C1-C14 The alkylthio group has a heterocyclic ring containing one or more heterocyclic atoms selected from N, O, and S.

In order to solve the above-mentioned problem, the present invention provides an organic light-emitting element including a hole transport layer between a pair of electrodes, and provides a hole transport compound having the hole transport layer according to the above <Chemical Formula 1> or <Chemical Formula 4> in the hole transport layer as Special organic light emitting element.

Effect of the Invention: The hole-transporting compound according to the present invention, based on a high hole-moving characteristic, introduces an allylamino group into a carbazole ring core having a relatively low free potential characteristic to reduce crystal formation and lower the free potential. Improve the hole transmission capacity to make it have the effect of increasing the service life.

Embodiments of the present invention are described in detail below.

The drawings are attached to explain the best embodiment of the present invention in detail as described below. Before explaining the present invention in detail, it must be explained that the terms or terms used in the following description of this specification and the scope of patent applications are not limited to their usual meanings or dictionary interpretations. Therefore, the embodiment described in this specification and the structure shown in the drawings are only the best embodiment of the present invention, and cannot cover all the technical ideas of the present invention. Please understand that there are many equivalents at the time of patent application. Material and derivative examples.

The material or compound used in the hole transport layer is used as a light-emitting material in an organic light-emitting diode (OLED) element.

Specifically, the hole transporting layer refers to a layer that can move the holes conducted at the anode through the hole injection layer to the light emitting layer more smoothly, and at the same time can stop the electrons transmitted from the cathode in the light emitting layer.

On the other hand, the material of the hole transport layer has a great influence on the performance of the OLED element. When designing, it is necessary to consider which material is used and how to synthesize it, because these factors have a very large impact on the overall performance of the OLED element.

The high degree of hole mobility is a basic requirement for the hole transport layer. To display this feature, a work function is required between the hole injection layer and the light-emitting layer. In order to stop the electrons in the light-emitting layer, it must have a low lowest unoccupied molecular orbital (LUMO) 値, When forming a thin film, it is preferred that it has an amorphous nature without crystallinity.

In addition, physically, a high glass transition temperature is required for high thermal stability, and for visible light to pass through in the visible light region, the film must be transparent.

In order to satisfy the above-mentioned requirements, the present invention provides a hole-transporting compound.

Specifically, the hole-transporting compound according to the present invention introduces an allylamino group into the core of a carbazole ring to reduce crystal formation, reduce free potential, and improve hole-transporting ability.

In addition, since the hole-transporting compound of the present invention is applicable to a triphenylamine derivative, it is possible to ensure that the device has a long service life.

On the other hand, according to the present invention, the hole-transporting compound having the above structure, the current method for synthesizing a carbazole-containing hole-transporting compound is to directly combine benzidine with bromobenzene or 4-bromo-1,1'-biphenyl. And then reacting with a carbazole derivative. However, such a synthesis method is either that the synthesis reaction is not smooth or that the yield is extremely low despite the synthesis reaction.

On the other hand, in order to solve such problems, the present invention introduces a halogen group or an amino group into a carbazole derivative first, and then reacts it with aniline or bisphenyl-4-amine to obtain 4,4'-dibromobiphenyl. By performing a coupling reaction, the target derivative of the hole-transporting compound according to the present invention can be obtained, which has a relatively stable yield and high purity.

Specifically, the hole transporting compound according to the present invention has a structure of the following <Chemical Formula 1>.

＜ Chemical Formula 1 ＞

In the above chemical formula, the above-mentioned R1 and R2 are each independently, which may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, or a substituted or unsubstituted C1-C14 Alkoxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C14 allylalkyl, substituted or unsubstituted C6-C14 ene Propoxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allylcarboxyl, or C1- The C14 alkylthio group is a heterocyclic ring containing one or more heterocyclic atoms selected from N, O, and S.

In addition, the hole-transporting compound according to the present invention has a structure of the following <Chemical Formula 4>.

＜ Chemical Formula 4 ＞

In the above chemical formula, the above-mentioned R1 and R2 are each independently, which may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, or a substituted or unsubstituted C1-C14 Alkoxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C14 allylalkyl, substituted or unsubstituted C6-C14 ene Propoxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allylcarboxyl, or C1-C14 The alkylthio group is a heterocyclic ring containing one or more heterocyclic atoms selected from N, O, and S.

The above <Chemical Formula 1> and <Chemical Formula 4> are hole-transporting compounds, which are used to introduce the allylamino group into the core of the carbazole ring to reduce the formation of crystals and reduce the free potential to improve the hole-transporting ability. The reason for the triphenylamine derivative is to ensure that the component has a long service life.

A preferred embodiment according to the present invention can be represented by the following <Chemical Formula 2>, <Chemical Formula 3>, and <Chemical Formula 5>.

＜ Chemical Formula 2 ＞

＜ Chemical Formula 3 ＞

＜ Chemical Formula 5 ＞

Compounds having the above-mentioned structures of <Chemical Formula 2>, <Chemical Formula 3>, and <Chemical Formula 5> have high energy levels of the highest filled sub-orbital (HOMO) energy levels, which are favorable for hole transport, and high The LUMO energy level can block the movement of electrons. Therefore, the overall hole transport characteristics of the compounds with the above-mentioned structures of <Chemical Formula 2>, <Chemical Formula 3>, and <Chemical Formula 5> are better than those of compounds such as TAPC, NPB, BPBPA, etc., which are generally used in the hole transport layer, because of their high energy Because of its conversion efficiency and glass transition temperature, its stability and service life are better than the above-mentioned compounds generally used in hole transport layers.

In addition, the organic light emitting element according to an embodiment of the present invention includes a hole transport layer between a pair of electrodes, and the hole transport layer includes any one of the above-mentioned <Chemical Formula 1> to <Chemical Formula 5>. Compound.

Organic light-emitting element : The structure and manufacturing method of an organic light-emitting element using a phosphorescent host compound according to the present invention will be described below.

According to the organic light emitting element of the present invention, a structure of a common light emitting element can be adopted. The structure can be changed if necessary. Basically, an organic light-emitting element has a structure including an organic film (light-emitting layer) between a first electrode (anode electrode) and a second electrode (cathode electrode), and also has a hole injection layer, a hole transport layer, and a hole. Suppression layer, electron injection layer, or electron transport layer. To explain the structure of the light-emitting element of the present invention, please refer to FIG. 1.

As shown in FIG. 1, according to the organic light emitting element of the present invention, a structure including an emission layer (EML) 50 between the anode electrode 20 and the cathode electrode 80 is provided between the anode electrode 20 and the light emitting layer 50. Contains a hole injection layer (HIL) 30 and a hole transporting layer (HTL) 40, or an electron transport layer (Electron Transport) between the light emitting layer 50 and the cathode electrode 80 Layer (ETL) 60 and an Electron Injection Layer (EIL) 70.

On the other hand, as shown in FIG. 1, an organic light emitting device according to a specific embodiment of the present invention can be manufactured according to the following method, but this is only a detailed example and is not limited to this method.

First, an anode electrode material is coated on a substrate 10 to form an anode electrode 20. Here, as the material of the substrate 10, a substrate generally used in the art may be used, but a glass substrate or a transparent plastic substrate having transparency, surface smoothness, easy handling, and excellent water resistance is preferred. In addition, as the anode electrode material formed on the substrate, indium tin oxide (ITO), tin oxide (SnO ₂ ), zinc oxide (ZnO), and the like, which are transparent and excellent in conductivity, can be used, but are not limited thereto.

Optionally, a hole injection layer 30 may be formed above the anode electrode 20. At this time, the hole injection layer 30 may be formed by a common vacuum evaporation method or a uniform coating method by centrifugal force. The substance for the hole injection layer is not particularly limited, and copper (II) phthalocyanine (CuPc) or IDE 406 (made by Idemitsu Kosan) can be selected.

Secondly, the hole transport layer 40 above the hole injection layer 30 is formed by a common method such as vacuum evaporation or uniform coating by centrifugal force. For the materials used in the hole transporting layer 40, N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-diphenyl-4,4'-di Amine (NPB), N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4'-diamine (TPD), N, N'-bis (naphthalene-1-yl) -N, N'-diphenyl-benzidine, N, N'-bis (naphthalene-1-yl) -N, N'-diphenyl-biphenyl Aniline: α-NPD) and the like, in a specific embodiment of the present invention, any one of the hole transporting compounds shown in the above <Chemical Formula 1> to <Chemical Formula 5> is contained.

Next, a light emitting layer 50 is formed over the hole transport layer 40. The light-emitting layer forming material can be selected from a compound containing a phosphorescent host and contains one or more main light-emitting materials, and can have a single-layer structure or a multi-layer structure with two or more layers. In this case, a compound containing <Chemical Formula 1> alone or another compound well known in the industry is used, for example, a blue light emitting dopant (iridium compound such as FIrppy or FIrpic) may be mixed and contained. The content of the phosphorescent host compound in the light-emitting layer is in a range of 1 to 95% by weight based on the total weight of the materials constituting the light-emitting layer.

The phosphorescent host compound can be formed by a vacuum evaporation method, or made by wet processing such as uniform coating by centrifugal force and then evaporated, and can also be made by laser induced thermal imaging (LITI). .

The exciton formed by the light-emitting substance above the light-emitting layer 50 may stay in the electron-transporting layer 60, or a hole blocking layer (HBL) may be added to prevent holes from transmitting to the electrons. The direction of the layer 60 is shifted, and the substance used in the hole suppression layer is not particularly limited, and a phenanthroline-based compound (for example, BCP) can be used. It can be made by a vacuum evaporation method or a centrifugal force uniform coating method.

In addition, the light-emitting layer 50 may have an electron transporting layer 60 thereon, which can be made by a vacuum evaporation method or a centrifugal uniform coating method. The material for the electron transport layer is not particularly limited, and TBPI and an aluminum composite colorant (for example, Alq3 (tris (8-hydroxyquinoline-aluminum)) can be used.

An electron injection layer 70 is provided above the electron transport layer 60, and can be made by vacuum evaporation or uniform coating by centrifugal force. The material used for the electron injection layer 70 is not particularly limited, and materials such as LIF, NACL, and CSF can be used.

Secondly, there is a cathode electrode 80 above the electron injection layer 70, which can be made by a vacuum evaporation method. At this point, the light-emitting element has been manufactured. Here, the cathode metal may be selected from lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver. (Mg-Ag), etc.

In addition, the organic light-emitting element according to the present invention has a layered structure as shown in FIG. 1. If necessary, one or two intermediate layers can be added, for example, a hole suppression layer can be added. In addition, the thickness of each layer of the light-emitting element can be in a range generally used in this field, and a suitable one can be selected according to its needs.

Hereinafter, specific examples of the present invention are listed and described in detail, but the present invention is not limited by the following examples.

Synthesis of Example Compound transmission hole according to the present invention Synthesis Example 1 9H - ethyl - carbazole Synthesis of

To 30 mL of tetrahydrofuran was added 10 g (0.05 mol) of 9H-carbazole. At 0 ° C, 2.88 g (0.12 mol) of sodium hydride was added, followed by stirring for 30 minutes. 7.85 g (0.072 mol) of bromoethane was added to the reaction solution, and the mixture was stirred at reflux for 3 hours. After confirming the completion of the reaction, return to normal temperature, add 100 ml of dichloromethane to the reaction solution, wash with 20% brine and extract. The organic layer was treated with anhydrous magnesium sulfate, and the filtrate obtained after filtration was distilled under reduced pressure, and then crystallized with n-hexane to obtain 10.8 g (92.3%) of the target compound 9H-ethyl-carbazole. Synthesis Example 29-- phenyl - 9H - carbazole Synthesis of

20 g (0.1 mol) of 9H-carbazole was added to 50 ml of tetrahydrofuran, and 5.76 g (0.24 mol) of sodium hydride was added at 0 ° C, followed by stirring for 30 minutes. 22.6 g (0.14 mol) of bromobenzene was added to the reaction solution, and 21.5 g (88.6%) of the target compound 9-phenyl-9H-carbazole was prepared according to the method of Synthesis Example 1. Synthesis Example 3 3 - bromo --9-- -ethyl - 9H - carbazole Synthesis of

After dissolving 12 g (0.061 mol) of ethylcarbazole in 300 ml of N, N-dimethylformamide, slowly add 10.9 g (0.061 mol) of N-bromosuccinimide, and under normal temperature in a nitrogen environment Stir for 12 hours. After confirming the completion of the reaction, 300 ml of water was added and the mixture was extracted three times with 800 ml of dichloromethane. The organic layer was collected and washed with 200 ml of water, and then treated with anhydrous magnesium sulfate. After filtration, the organic layer was decompressed. After concentration, the obtained solid was recrystallized from 200 ml of isopropylamine to obtain 14.3 g (84.1%) of the target compound 3-bromo-9-ethyl-9H-carbazole as light brown crystals. Synthesis Example 4 3 - bromo --9-- phenyl - 9H - carbazole Synthesis of

After dissolving 14.8 g (0.061 mol) of 9-phenyl-9H-carbazole in 500 ml of N, N-dimethylformamide, and slowly adding 10.9 g (0.061 mol) of N-bromosuccinimine, Stir at room temperature under a nitrogen atmosphere for 12 hours. After confirming the completion of the reaction, 300 ml of water was added and extracted three times with 800 ml of dichloromethane. The collected organic layer was washed with 200 ml of water and treated with anhydrous magnesium sulfate. After filtration, the organic layer was decompressed. After concentration, the obtained solid was separated by silica gel chromatography, and a mixed solution of dichloromethane to n-hexane of 1: 5 was used as a dissolution separation solution (washing solution) to obtain the target compound 3-bromo-9-9 as pale yellow crystals. 12.7 g (64.7%) of phenyl-9H-carbazole. Synthesis Example 59-- ethyl - 3 - (4,4,5,5 - tetramethyl-1,3,2-dioxaborolan-2-yl) -9H- carbazole Synthesis of

14.2 g (0.052 mol) of 3-bromo-9-ethyl-9H-carbazole, 15.7 g (0.062 mol) of bis (pinacol) diborane, 10.1 g (0.103 mol) of potassium acetate, and tertiary triphenyl After 3.4 g (0.003 mol) of phosphonium palladium (0) was dissolved in 300 ml of 1,4-dioxane, the mixture was heated and stirred at 110 ° C. for 18 hours. After confirming the completion of the reaction, the reaction solution was filtered through silica gel, extracted with 1 L of ethyl acetate, and then washed twice with saturated saline and once with water. The organic layer was treated with anhydrous magnesium sulfate, and after filtration, the organic layer was concentrated under reduced pressure. The obtained residue was separated by a silica gel layer analysis method, and a mixed solution of dichloromethane to n-hexane of 1:10 was used as a dissolution separation solution. The target compound 9-ethyl-3- (4,4,5,5-tetramethyl-1,3,2-dioxolane-2-yl) -9H-carbazole was obtained as off-white crystals. 10.4 g (62.2%). Synthesis Example 69-- phenyl - 3 - (4,4,5,5 - tetramethyl-1,3,2-dioxaborolan-2-yl) -9H- carbazole Synthesis of

16.8 g (0.052 mol) of 3-bromo-9-phenyl-9H-carbazole, 15.7 g (0.062 mol) of bis (pinacol) diborane, 10.1 g (0.103 mol) of potassium acetate, and quaternary tribenzene After dissolving 3.4 g (0.003 mol) of phosphonium palladium (0) in 400 ml of 1,4-dioxane, it was processed according to the method described in Synthesis Example 5, separated by silica gel chromatography, and compared with n-hexane by dichloromethane. A mixed solution of 1: 5 was used as a dissolution separation liquid (washing liquid) to obtain the target compound 9-phenyl-3- (4,4,5,5-tetramethyl-1,3,2-di Oxaborolan-2-yl) -9H-carbazole 11.1 g (57.8%). Example 7 Synthesis of 3 - (4 - bromophenyl) --9-- -ethyl - 9H - carbazole Synthesis of

10.3 g (0.032 mol) of 9-ethyl-3- (4,4,5,5-tetramethyl-1,3,2-dioxorane-2-yl) -9H-carbazole , 9.05 g (0.032 mol) of 1-bromo-4-iodobenzene, 1.87 g (0.002 mol) of quaternary triphenylphosphine palladium (0), dissolved in 200 ml of tetrahydrofuran, and stirred for 30 minutes. After adding 200 ml of a 2N-potassium carbonate aqueous solution to the reaction solution, the mixture was vigorously stirred at 70 ° C. for 18 hours. After confirming the completion of the reaction, the residue obtained by distilling the reaction solution under reduced pressure was added to 500 ml of dichloromethane, washed several times with water, and the organic layer was treated with anhydrous magnesium sulfate. After filtration, the organic layer was concentrated under reduced pressure. Separated by silica gel chromatography, and a mixed solution of dichloromethane to n-hexane of 1:10 was used as a dissolution separation solution (washing solution) to obtain the target compound 3-(4-bromophenyl) -9 as a gray-brown crystal. -Ethyl-9H-carbazole 6.2 g (55.3%). Synthesis Example 8 3 - (4 - bromophenyl) --9-- phenyl - 9H - carbazole Synthesis of

11.8 g (0.032 mol) of 9-phenyl-3- (4,4,5,5-tetramethyl-1,3,2-dioxolane-2-yl) -9H-carbazole 9.05 g (0.032 mol) of 1-bromo-4-iodobenzene, 1.87 g (0.002 mol) of quaternary triphenylphosphine palladium (0), dissolved in 200 ml of tetrahydrofuran, and the residue obtained in accordance with the method of Synthesis Example 7 was silicon gel. Separation by chromatographic analysis, and using a mixed solution of ethyl acetate to n-hexane of 1: 5 as a dissolution separation liquid (washing liquid) to obtain the target compound 3- (4-bromophenyl) -9-benzene as white crystals. Base-9H-carbazole 8.4 g (65.8%). Synthesis Example 9 4 - (9 - ethyl - 9H - carbazole - 3 - yl) - N - phenyl aniline Synthesis of

Add 6.2 g (0.018 mol) of 3- (4-bromophenyl) -9-ethyl-9H-carbazole, 1.8 g (0.019 mol) of aniline, 1.8 g (0.019 mol) of sodium-tert-butanol to 150 ml of tetrahydrofuran , Stir for 30 minutes at room temperature. A solution of 0.51 g (0.001 mol) of bis (benzylacetone) palladium (0) in 1.79 g (0.009 mol) of tri-tert-butylphosphine (50% xylene) was added to the reaction solution, and the solution was refluxed. Stir for 18 hours. After confirming the completion of the reaction, the reaction solution was filtered with silica, 1 L of ethyl acetate was added, and the mixture was extracted twice with saturated saline, and then washed once with water. The organic layer was treated with anhydrous magnesium sulfate, and after filtration, the residue obtained by concentrating the organic layer under reduced pressure was separated by a silica gel layer analysis method, and a mixed solution of dichloromethane to n-hexane of 1: 2 was used as the elution separation solution (Washing liquid), to give the target compound 4- (9-ethyl-9H-carbazole-3-yl) -N-phenylaniline 2.7 g (41.4%) as white crystals. Aniline Synthesis Example 10 N - phenyl --4-- (group 9 - phenyl - 9H - carbazole - - 3)

Add 10 grams (0.025 mol) of 3- (4-bromophenyl) -9-phenyl-9H-carbazole, 2.58 grams (0.028 mol) of aniline, 2.91 grams (0.03 mol) of sodium-tert-butanol, and add 100 toluene ml, heated at 60 ° C. A solution of 3.2 g (0.015 mol) of tri-tert-butylphosphine and 0.72 g of bis (benzylacetone) palladium (0) after being dissolved was added to the reaction solution in one breath, and stirred under reflux for 24 hours. After confirming the completion of the reaction, cool to normal temperature, filter the reaction with silica, add 200 ml of ethyl acetate, wash several times with water, and treat the organic layer with anhydrous magnesium sulfate. After filtration, the organic layer was concentrated under reduced pressure. The obtained residue was dissolved in a small amount of ethyl acetate, 300 ml of excess n-heptane was added, and the mixture was vigorously stirred at 0 ° C for 1 hour to form crystals. The target compound, N-phenyl-4, was obtained as white crystals after filtration. 9 grams of 9-phenyl-9H-carbazol-3-yl) aniline (40.6%). Synthesis Example 11 N - (4 - (9 - phenyl - 9H - carbazole - 3 - yl) phenyl) - [1,1 '- biphenyl] --4-- of amine

10 g (0.025 mol) of 3- (4-bromophenyl) -9-phenyl-9H-carbazole, 5.1 g (0.030 mol) of bisphenyl-4-amine, 3.62 g (0.038) of sodium-tert-butanol mol) was added to 150 ml of toluene, and stirred at room temperature for 30 minutes. A solution obtained by dissolving 3.05 g (0.013 mol) of tri-tert-butylphosphine (50% xylene) in bis (benzylacetone) palladium (0) (0.72 g (0.0013 mol)) was added to the reaction solution and stirred under reflux for 22 hour. After confirming the completion of the reaction, cool to normal temperature, filter the reaction with silica, add 300 ml of dichloromethane, wash with water several times, and treat the organic layer with anhydrous magnesium sulfate. After filtration, depressurize the organic layer. A small amount of tetrahydrofuran was added to the residue obtained after concentration, and 500 ml of n-hexane was added, followed by vigorous stirring for 2 hours to form crystals. After filtration, the objective compound N- (4- (9-phenyl-9H-carbazole) -3-yl) phenyl)-[1,1'-biphenyl] -4-amine 6 g (49.1%). Synthesis Example 12 N4, N4' -bis (4- (9- ethyl -9H- carbazol- 3 -yl ) phenyl ) -N4, N4' -diphenyl- [1,1'- biphenyl ]- Synthesis of 4,4'- diamine

Add 2.7 g (0.007 mol) of 4- (9-ethyl-9H-carbazol-3-yl) -N-phenylaniline, 1.1 g (0.004 mol) of 4,4'-dibromobiphenyl, and sodium-tert After dissolving 0.78 g (0.008 mol) of butanol in 80 ml of tetrahydrofuran, stir at room temperature for 30 minutes. After the reaction solution was heated to 40 ° C, a solution obtained by dissolving 0.08 g (0.0004 mol) of palladium (II) acetate with 0.75 g (0.004 mol) of tri-tert-butylphosphine (50% xylene) was added under reflux. Stir for 30 hours. After the reaction solution was cooled to normal temperature, the reaction solution was filtered with silica, 1 L of ethyl acetate was added, extraction was performed twice with saturated saline, and the solution was washed once with water. The organic layer was treated with anhydrous magnesium sulfate. After filtration, the residue obtained by concentrating the organic layer under reduced pressure was separated by a silica gel layer analysis method, and a mixed solution of dichloromethane to ethyl acetate to n-hexane was 1: 4: 2. As a dissolution separation solution (washing solution), the target compound N4, N4'-bis (4- (9-ethyl-9H-carbazol-3-yl) phenyl) -N4, N4'- Diphenyl- [1,1'-biphenyl] -4,4'-diamine 0.9 g (13%). Figure 5 shows the NMR data of the hole-transporting compound synthesized by this method. Synthesis Example 13 N4, N4' -diphenyl- N4, N4' -bis (4- (9- phenyl -9H- carbazol- 3 -yl ) phenyl )-[1,1'- biphenyl ]- Synthesis of 4,4'- diamine

3.17 g (0.01 mol) of 4,4'-dibromo-1,1'-biphenyl and 2 g (0.02 mol) of sodium tert-butoxide were added to 300 ml of toluene and heated to 60 ° C. To the reaction solution was added 0.2 g (0.0002 mol) of tri (dibenzylideneacetone) dipalladium (0) dissolved in 2 g (0.008 mol) of tri-tert-butylphosphine (50% xylene), and the solution was refluxed. Stir for 24 hours. After confirming the completion of the reaction, after cooling to normal temperature, filtering with silica dioxide, adding 500 ml of ethyl acetate, washing with water several times, treating the organic layer with anhydrous magnesium sulfate, filtering, and concentrating the organic layer under reduced pressure After the residue was dissolved in a small amount of tetrahydrofuran, 500 ml of n-heptane was added, and the mixture was stirred vigorously at 0 ° C for 2 hours to obtain a brown solid. After filtration, the residue was separated by silica gel chromatography and separated by dichloromethane to ethyl acetate to hexane. A 1: 1 mixed solution of alkane was used as the elution separation liquid (washing liquid) to obtain the target compound N4, N4'-diphenyl-N4, N4'-bis (4- (9-phenyl- 9H-carbazol-3-yl) phenyl)-[1,1'-biphenyl] -4,4'-diamine 1.5 g (7.7%). Figure 6 shows the NMR data of the hole-transporting compound synthesized by this method. Synthesis Example 14 N4, N4' -bis ((1,1'- biphenyl ) -4 -yl ) -N4, N4' -bis (4- (9- phenyl -9H- carbazol- 3 -yl ) Synthesis of phenyl )-[1,1' -biphenyl ] -4,4'- diamine

1.3 g (0.004 mol) of 4,4'-dibromobiphenyl, 4.3 g (0.009 mol) of N- (4- (9-phenyl-9H-carbazol-3-yl) phenyl)-[1, 1'-biphenyl] -4-amine, 1 g (0.0104 mol) of sodium-tert-butanol were added to 50 ml of toluene, and stirred at normal temperature for 30 minutes. After the reaction solution was heated to 40 ° C, tris-di-tert-butylphosphine (50% xylene) was added to dissolve tris (dibenzylideneacetone) dipalladium (0), 0.19 g (0.0002 mol) in 0.5 g (0.002 mol). The resulting solution was stirred under reflux for 30 hours. After confirming the completion of the reaction, the mixture was cooled to normal temperature, filtered with silica, 300 ml of dichloromethane was added, and washed several times with water. The organic layer was treated with anhydrous magnesium sulfate. After filtration, the organic layer was concentrated under reduced pressure , Separated by silica gel chromatography, and a mixed solution of dichloromethane to ethyl acetate to n-hexane of 1: 1: 2 was used as a dissolution separation liquid (washing liquid) to obtain the target compound N4, N4 'as white crystals. -Bis ((1,1'-biphenyl) -4-yl) -N4, N4'-bis (4- (9-phenyl-9H-carbazol-3-yl) phenyl)-[1, 1'-biphenyl] -4,4'-diamine 2.2 g (47.3%). Figure 7 shows the NMR data of the hole-transporting compound synthesized by this method.

The compounds according to the specific embodiments of the present invention, for example, hole-transporting compounds having the above-mentioned structures of <Chemical Formula 1> to <Chemical Formula 5>, those who have such synthesis techniques can easily synthesize them by referring to Synthesis Examples 1-14 above.

According to Synthesis Examples 12 to 14 Synthesis of the hole transport compound itself results of evaluation for the compound produced according to the above-described Synthesis Example 1-3 of the representative physical properties, results in the following <Table 1> FIG.

＜ 表 1 ＞ Table 1 UVmax: absorption wavelength of substance measured by spectrometer and cyclic voltammetry PLmax: emission wavelength of substance measured by spectrometer and cyclic voltammetry HOMO, LUMO, band gap: determined by spectrometer and cyclic voltammetry T1 measurement by cyclic voltammetry: triplet energy in the form of a thin film (confirmed by photoluminescence measurement at 77K) TID: degradation temperature of a substance (confirmed by TGA) Tg: glass transition temperature

As shown in the above <Table 1>, the hole-transporting compound according to the present invention has a high glass transition temperature and a HOMO energy level that is advantageous in hole-transmission, and also has a high LUMO energy level. In addition, it can be confirmed that the TID corresponds to 500 ° C or higher, and has a very thin characteristic at nearly 600 ° C.

In addition, the above substances prepared according to the above Synthesis Examples 1 to 14 have the advantage of higher yield.

According to applicable Synthesis Examples 12 to 14 Synthesis of electrically results hole transport compound of the organic light emitting device Comparative Example 1 An ITO substrate was washed and painted on the light emitting area size of 3 mm × 3 mm of the pattern (patterning). After placing the substrate in the vacuum chamber, adjust the base pressure to 1 × 10 ^-6 torr, dissolve the hole injection material in PEDOT: PSS (conductive coating), apply the centrifugal force evenly on the anode ITO, and on the hole transmission layer A film having a thickness of 30 nm was formed with a chemical formula of 4,4'-cyclohexylenebis [N, N-bis (4-methylphenyl) aniline] (TAPC). After that, the light-emitting layer above the hole-transport layer is 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) was doped with FIrpic as a light-emitting dopant at a doping concentration of 12% to form a 30 nm thickness film, and then a PCB was vacuum-evaporated thereon to form a film Hole blocking layer with a thickness of 10 nm. Next, Alq3 was vacuum-evaporated on the electron transport layer to form a 30 nm-thick film, LiF of the electron injection layer was formed to a 1.0 nm-thick film, and Al at the cathode was formed to a 100 nm-thick film to obtain an organic light-emitting film. The light-emitting characteristics of the device were evaluated by measuring the relative changes in current, voltage, and luminance in real time. The results are shown in the following <Table 2>.

Comparative Example 2 The ITO substrate was patterned with a light emitting area size of 3 mm × 3 mm, and washed. After the substrate was installed in a vacuum chamber, the base pressure was adjusted to 1 × 10 ^-6 torr, and the hole-injected material was dissolved in PEDOT: PSS (conductive paint), and was evenly coated on the anode ITO by centrifugal force. In Comparative Example 2 Use a compound of the formula N, N'-bis (1-naphthyl) -N, N'-diphenyl- (1,1'-biphenyl) -4,4'diamine (NPB) A film with a thickness of 30 nm was formed on the hole transport layer. After that, the light-emitting layer above the hole-transport layer is 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) and FIrpic as a light-emitting dopant were doped at a doping concentration of 12% to form a 30 nm-thick film, and then treated in accordance with the method of Comparative 1 to evaluate the light-emitting characteristics. The lifetime of the device was evaluated by measuring the relative changes in current, voltage, and brightness in real time. The results are shown in the following <Table 2>.

Comparative Example 3 The ITO substrate was patterned with a light emitting area size of 3 mm × 3 mm and washed. After the substrate was placed in a vacuum chamber, the base pressure was adjusted to 1 × 10 ^-6 torr, and the hole-injected substance was dissolved in PEDOT: PSS (conductive paint), and was evenly coated on the anode ITO by centrifugal force. In Comparative Example 3 The chemical formula is N, N, N ', N''-tetrakis[1,1'biphenyl]-4-yl]-(1,1'-biphenyl)-4,4'diamine (BPBPA) The compound was used to form a 30 nm thick film on the hole transport layer. After that, the light-emitting layer above the hole-transport layer is 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) and FIrpic as a light-emitting dopant were doped at a doping concentration of 12% to form a 30-nm-thick film, and then processed in accordance with the method of Comparative Example 1 to evaluate the light-emitting characteristics. The life of the device was evaluated by measuring the relative changes in current, voltage, and brightness in real time. The results are shown in the following <Table 2>.

Specific embodiment 1 The ITO substrate is painted with a pattern with a light emitting area size of 3 mm × 3 mm and washed. After placing the substrate in a vacuum chamber, adjust the base pressure to 1 × 10 ^-6 torr, dissolve the hole injection material in PEDOT: PSS (conductive coating), apply the centrifugal force evenly on the anode ITO, and deposit on the hole transmission layer. N4, N4'-bis (4- (9-ethyl-9H-carbazol-3-yl) phenyl) -N4, N4'-diphenyl- [1,1 ' -Biphenyl] -4,4'-diamine to form a film with a thickness of 30 nm. After that, the light-emitting layer above the hole transporting layer was 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) and FIrpic as a light-emitting dopant were doped at a doping concentration of 12% to form a 30-nm-thick film, and then processed in accordance with the method of Comparative Example 1 to evaluate the light-emitting characteristics. The life of the device was evaluated by measuring the relative changes in current, voltage, and brightness in real time. The results are shown in the following <Table 2>.

Specific embodiment 2 The ITO substrate is painted with a pattern with a light emitting area size of 3 mm × 3 mm, and then washed. After placing the substrate in a vacuum chamber, adjust the base pressure to 1 × 10 ^-6 torr, dissolve the hole injection material in PEDOT: PSS (conductive coating), apply the centrifugal force evenly on the anode ITO, and deposit on the hole transmission layer. Using N4, N4'-diphenyl-N4, N4'-bis (4- (9-phenyl-9H-carbazol-3-yl) phenyl)-[1,1 'produced in Synthesis Example 13 above -Biphenyl] -4,4'-diamine to form a film with a thickness of 30 nm. After that, the light-emitting layer above the hole transporting layer was 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) and FIrpic as a light-emitting dopant were doped at a doping concentration of 12% to form a 30-nm-thick film, and then processed in accordance with the method of Comparative Example 1 to evaluate the light-emitting characteristics. The life of the device was evaluated by measuring the relative changes in current, voltage, and brightness in real time. The results are shown in the following <Table 2>.

Specific embodiment 3 The ITO substrate is painted with a pattern with a light emitting area size of 3 mm × 3 mm, and then washed. After placing the substrate in a vacuum chamber, adjust the base pressure to 1 × 10 ^-6 torr, dissolve the hole injection material in PEDOT: PSS (conductive coating), apply the centrifugal force evenly on the anode ITO, and deposit on the hole transmission layer. Using N4, N4'-bis ((1,1'-biphenyl] -4-yl) -N4, N4'-bis (4- (9-phenyl-9H-carbazole) produced in Synthesis Example 14 above -3-yl) phenyl)-[1,1'-biphenyl] -4,4'-diamine to form a film with a thickness of 30 nm. After that, the light-emitting layer above the hole transporting layer was 9,9-bis (9-ethyl-9H-carbazol-3-yl) -2,7-dimethyl-9H-thioxan-10, 10-dioxide (BPM-B102) and FIrpic as a light-emitting dopant were doped at a doping concentration of 12% to form a 30-nm-thick film, and then processed in accordance with the method of Comparative Example 1 to evaluate the light-emitting characteristics. The life of the device was evaluated by measuring the relative changes in current, voltage, and brightness in real time. The results are shown in the following <Table 2>.

＜ 表 2 ＞ Table 2

As shown in <Table 2>, the hole-transporting compound according to the specific embodiment of the present invention has a HOMO energy level and can easily inject common substances such as TAPC, NPB, and BPBPA substances into the hole, and has high LUMO energy. It can block electrons, and it has excellent hole transmission characteristics. It is suitable for the hole transmission layer of organic light-emitting elements. Because it has high energy efficiency and high Tg, it has stability and long service life.

In FIG. 2, the wavelengths versus normalized EL intensities of the above Comparative Examples 1 to 3 and Specific Examples 1 to 3 are shown in a graph.

In FIG. 2, Reference Example 1 is referred to as Comparative Example 1, Reference Example 2 is referred to as Comparative Example 2, Reference Example 3 is referred to as Comparative Example 3, and Sample Example 1 is referred to as Specific In the first embodiment, a sample example 2 is referred to as a specific embodiment 2, and a sample example 3 is referred to as a specific embodiment 3.

As shown in FIG. 2, it is confirmed that the comparative examples 1 to 3 and the specific examples 1 to 3 have almost the relationship between the wavelength and the normalized EL intensity.

In FIG. 3, the results of the voltage vs. luminance of the above Comparative Examples 1 to 3 and Specific Examples 1 to 3 are shown in a graph.

In FIG. 3, Reference Example 1 is referred to as Comparative Example 1, Reference Example 2 is referred to as Comparative Example 2, Reference Example 3 is referred to as Comparative Example 3, and Sample Example 12 is referred to as Specific In the first embodiment, a sample example 13 is referred to as a specific embodiment 2, and a sample example 14 is referred to as a specific embodiment 3.

As shown in FIG. 3, the specific examples 1 to 3 have relatively higher voltage efficiency than the comparative examples 1 to 3.

In FIG. 4, the results of the above-mentioned Comparative Examples 1 to 3 and Specific Examples 1 to 3 according to time on the luminance are shown graphically.

In FIG. 4, Reference Example 1 is referred to as Comparative Example 1, Reference Example 2 is referred to as Comparative Example 2, Reference Example 3 is referred to as Comparative Example 3, and Sample Example 1 is referred to as Specific In the first embodiment, a sample example 2 is referred to as a specific embodiment 2, and a sample example 3 is referred to as a specific embodiment 3.

As shown in FIG. 4, the specific examples 1 to 3 have a relatively long life compared with the comparative examples 1 to 3.

The above-mentioned drawings and description disclose the preferred embodiment. The present invention is not limited to the specific embodiments described above. Those who have relevant knowledge in the technical field to which the present invention belongs can make various changes and modifications within the scope not departing from the spirit of the present invention. The technology for protecting the present invention should be formulated within the scope of the patent application. The real scope.

10‧‧‧ substrate

20‧‧‧Anode electrode

30‧‧‧ Hole injection layer

40‧‧‧ Hole Transmission Layer

50‧‧‧Light emitting layer

60‧‧‧ electron transmission layer

70‧‧‧ electron injection layer

80‧‧‧ cathode electrode

FIG. 1 is a cross-sectional view showing a structure of an organic light emitting device according to a specific embodiment of the present invention. FIG. 2 to FIG. 4 are graphs of experimental results according to the embodiment of the present invention. 5 to 7 are nuclear magnetic resonance (NMR) data according to an embodiment of the present invention.

Claims (6)

A hole-transporting compound having a structure as shown in <Chemical Formula 1>: <Chemical Formula 1> wherein R1 and R2 are each independently, which may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, or a substituted or unsubstituted C1-C14 Alkoxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C1 allylalkyl, substituted or unsubstituted C6-C14 ene Propoxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allylcarboxyl, or C1- C14 alkylthio; This heterocyclic ring contains one or more heterocyclic atoms selected from nitrogen (N), oxygen (O), and sulfur (S). The hole-transporting compound according to item 1 of the scope of application for a patent, wherein the compound has the characteristics shown in <Chemical Formula 2>: <Chemical Formula 2>. The hole-transporting compound according to item 1 of the scope of application for a patent, wherein the compound has the characteristics shown in <Chemical Formula 3>: <Chemical Formula 3>. A hole-transporting compound having a structure as shown in <Chemical Formula 4>: <Chemical Formula 4> wherein R1 and R2 are each independently, which may be a hydrogen atom, a cyano group, a hydroxyl group, a thiol group, a halogen atom, a substituted or unsubstituted C1-C14 alkyl group, or a substituted or unsubstituted C1-C14 Alkoxy, substituted or unsubstituted C2-C14 alkenyl, substituted or unsubstituted C6-C14 allyl, substituted or unsubstituted C7-C1 allylalkyl, substituted or unsubstituted C6-C14 ene Propoxy, substituted or unsubstituted C4-C14 heteroallyl, substituted or unsubstituted C5-C14 heteroallyl alkyl, substituted or unsubstituted C4-C14 heteroallyloxy, substituted or unsubstituted C5-C14 cycloalkyl, substituted or unsubstituted C4-C14 heterocycloalkyl, substituted or unsubstituted C2-C14 alkylcarbonyl, substituted or unsubstituted C7-C30 allylcarboxyl, or C1- C14 alkylthio; This heterocyclic ring contains one or more heterocyclic atoms selected from nitrogen (N), oxygen (O), and sulfur (S). The hole-transporting compound as described in item 4 of the scope of application for a patent, wherein the compound has the characteristics shown in <Chemical Formula 5>: <Chemical Formula 5>. An organic light-emitting element includes a pair of electrodes, and a hole-transporting layer is included between the pair of electrodes. The hole-transporting layer has the hole-transporting compound according to any one of claims 1 to 5 of the patent application scope.