KR20210070469A - Hole Transfer Compound and Organic Light-Emitting Diodes Using The same - Google Patents

Abstract

The present invention relates to a hole transport compound represented by a chemical formula 1, and an organic light emitting device including the same. The hole transport compound according to the present invention is based on high hole transport properties and reduces ionization potential to improve hole transport ability, has high compatibility with other layers of general OLED devices and has high hole mobility and long lifespan.

Description

Hole Transfer Compound and Organic Light-Emitting Diodes Using The Same

The present invention relates to a hole transport compound and an organic light emitting device including the same, and more particularly, to improve hole transport ability by reducing ionization potential and based on high hole transport characteristics, and high compatibility with other layers of general OLED devices It relates to a hole transport compound and an organic light emitting device including the same, which has a high hole mobility, a long lifetime based on a high glass transition temperature, and a low driving voltage.

An electroluminescent device (EL device) is a self-luminous display device, and has a wide viewing angle, excellent contrast, and a fast response time.

The EL device is classified into an inorganic EL device and an organic EL device according to a material for forming an emitting layer. Here, the organic EL device has advantages in that it has superior luminance, driving voltage and response speed characteristics and can be multicolored compared to the inorganic EL device.

A typical organic EL device has a structure in which an anode is formed on a substrate, and a hole transport layer, a light emitting layer, an electron transport layer, and a cathode are sequentially formed on the anode. Here, the hole transport layer, the light emitting layer, and the electron transport layer are organic thin films made of an organic compound.

The driving principle of the organic EL device having the above-described structure is as follows. When a voltage is applied between the anode and the cathode, holes injected from the anode are moved to the emission layer via the hole transport layer. Meanwhile, electrons are injected from the cathode into the emission layer via the electron transport layer, and carriers recombine in the emission layer region to generate excitons. This exciton changes from an excited state to a ground state, whereby molecules of the light emitting layer emit light, thereby forming an image. The light emitting material is divided into a fluorescent material using excitons in a singlet state and a phosphorescent material using a triplet state according to their light emission mechanism.

Until now, many studies have been conducted on amine derivatives having a carbazole skeleton as a hole transport material used in such an organic light emitting device, but there have been many difficulties in practical application due to a higher driving voltage, low efficiency, and short lifespan.

Accordingly, efforts have been made to develop an organic light emitting diode having low voltage driving, high luminance, and long lifespan using a material having excellent properties.

Republic of Korea Patent Publication No. 10-1631507

In order to solve the above problems, the present invention is based on high hole transport characteristics and improves hole transport ability by reducing ionization potential, has high compatibility with other layers of general OLED devices, high hole mobility, high glass An object of the present invention is to provide a hole transport compound and an organic light emitting device including the same, which exhibit characteristics having a long lifespan and a low driving voltage based on a transition temperature.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula (1).

[Formula 1]

In Formula 1,

R1, R2, and R3 are each independently phenyl, naphthyl, triphenylamine, a phenyl-phenylcarbazole derivative, or a fluorene derivative.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula (2).

[Formula 2]

R4 is triphenylamine or a phenyl-phenylcarbazole derivative.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula (2).

[Formula 3]

R5 is triphenylamine or a phenyl-phenylcarbazole derivative.

In order to solve the above problems, the present invention provides a hole transport compound represented by the following formula.

In order to solve the above problems, the present invention provides an organic light emitting device including a hole transport layer between a pair of electrodes, wherein the hole transport layer includes a hole transport compound according to Chemical Formula 1, Chemical Formula 2, or Chemical Formula 3 It provides an organic light emitting device, characterized in that.

The hole transport compound according to the present invention is based on high hole transport properties and improves hole transport ability by reducing ionization potential, has high compatibility with other layers of general OLED devices, and has high hole mobility and long lifespan. to perform

1 is a cross-sectional view showing the structure of an organic light emitting device according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail.

A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings as follows. Prior to the detailed description of the present invention, the terms or words used in the present specification and claims described below should not be construed as being limited to conventional or dictionary meanings. Therefore, the configuration shown in the embodiments and drawings described in the present specification is only the most preferred embodiment of the present invention and does not represent all the technical spirit of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

Materials or compounds used in the hole transport layer play a role as one of the light emitting materials in the OLED device.

Specifically, the hole transport layer functions to more smoothly move the holes transferred from the anode through the hole injection layer to the light emitting layer, and at the same time serves to bind the electrons transferred from the cathode to the light emitting layer.

On the other hand, the electroporation transport layer materials greatly affect the performance of the OLED device, and the overall performance of the OLED device may change significantly depending on how the material is designed and synthesized.

A basic requirement of the hole transport layer is high hole mobility. In order to exhibit these characteristics, it must have a work function located between the hole injection layer and the light emitting layer, and it requires a low LUMO value to confine electrons to the light emitting layer, and has an amorphous characteristic in which crystallinity does not appear when a thin film is formed. desirable.

In addition, the hole transport layer has a high glass transition temperature in order to physically have high thermal stability, and the film must have light transmittance in the visible region so that visible light can pass therethrough in the visible region.

On the other hand, not only the physical properties of the hole transport layer, but also the hole injection layer, the light emitting layer, and the electrode layer have high compatibility, so that the overall efficiency and lifespan of the OLED device must be maintained at a certain level or more.

In order to satisfy the above requirements, the hole transport compound of the present invention was derived.

Specifically, the hole transport compound according to the present invention has a structurally stable monophenyl diamine central structure, but has a basic structure in which a fluorene group having thermal and conformational stability is bonded.

Such a fluorene group imparts molecular stericity to the entire hole transport compound, and the hole hydrogen compound of the present invention has aromatic characteristics.

On the other hand, the hole transport compound according to the present invention has a structure robust to the above structure, and contains at least one of a phenyl-phenylcarbazole derivative and a triphenylamine derivative having excellent charge carrier mobility and low ionization potential. It can also have a high glass transition temperature. Such phenyl-phenylcarbazole derivatives and triphenyl amine derivatives make the structure in which the fluorene group is bonded to the monophenyl diamine central structure more robust, so that a high glass transition temperature can be obtained, and the hole mobility can be significantly improved. have.

Specifically, the hole transport compound according to the present invention has a structure represented by the following Chemical Formulas 1, 2, and 3:

[Formula 1]

In Formula 1,

R1, R2, and R3 are each independently phenyl, naphthyl, triphenyl amine, a phenyl-phenylcarbazole derivative, or a fluorene derivative, and at least one of R1, R2, and R3 is triphenyl amine, phenyl-phenyl carbazole derivatives.

[Formula 2]

R4 is triphenylamine or a phenyl-phenylcarbazole derivative.

[Formula 3]

R5 is triphenylamine or a phenyl-phenylcarbazole derivative.

The compound according to the present invention having the structure of the above formula has a favorable HOMO energy level for hole transport, and can block electron movement by having a high LUMO energy level.

Accordingly, the compound having the structure according to the above formulas has better overall hole transport properties than TAPC, N[B, and BPBPA, which are generally used as a hole transport layer, has high energy efficiency, and is a general OLED device with an appropriate glass transition temperature. It is excellent in overall stability by having compatibility and long lifespan.

In addition, the hole transport compound according to the embodiments of the present invention is a compound used in the hole transport layer, and the hole transport layer more smoothly moves the holes transferred from the anode through the hole injection layer to the light emitting layer, and electrons transferred from the cathode It is a layer that performs a role even having a function of constraining the light emitting layer.

A basic requirement of the hole transport layer (HTL) is to have high hole mobility, and therefore, effective hole injection from the anode into the light emitting layer (EML) should be performed.

Materials well-known for these materials are aromatic amine-based materials with an amine structure. They must form a film that does not crystallize during the deposition process of the material, have high thermal stability, and have excellent contact properties/flatness with the anode. And when the thin film is formed in the visible light region, it should have a transparent property.

The present invention can have a clear difference in electron distribution in HOMO and LUMO states by bonding at least one phenyl-phenylcarbazole or triphenyl amine to the parent nucleus structure of monophenyl diamine to which a fluorene derivative is bonded. . Specifically, in the case of having the same structure as the present invention, it can have a HOMO value of 5.2 eV and a LUMO value of 2.5 eV.

The compounds according to the above embodiments of the present invention may be represented by the following chemical formula.

In such a structure, by having at least one fluorene group and at least one phenyl-phenylcarbazole or triphenylamine around the parent nucleus, it has a structure capable of maximizing the longest effective conjugation (LONGEST EFFECTIVE CONJUGATION).

When any one of the four branches around the parent nucleus including monophenyl becomes phenyl carbazole or triphenylamine, and has a DAD molecular structure in the form of a star, it may have an advantage in terms of the longest effective conjugation. .

organic light emitting device

Hereinafter, the structure and manufacturing method of an organic light emitting device employing the phosphorescent host compound according to the present invention will be described.

The organic light emitting device according to the present invention may adopt a structure of a conventional light emitting device, and the structure may be changed as necessary. Basically, an organic light emitting device has a structure including an organic film (light emitting layer) between a first electrode (anode electrode) and a second electrode (cathode electrode), and includes a hole injection layer, a hole transport layer, a hole suppression layer, an electron injection layer, or An electron transport layer may be further included. Reference is made to FIG. 1 to describe the structure of the light emitting device of the present invention.

Referring to FIG. 1 , the organic light emitting device according to the present invention has a structure including a light emitting layer 50 between the anode electrode 20 and the cathode electrode 80 , and between the anode electrode 20 and the light emitting layer 50 . The hole injection layer 30 and the hole transport layer 40 are included, and the electron transport layer 50 and the electron injection layer 70 are included between the emission layer 50 and the cathode electrode 80 .

On the other hand, the organic light emitting diode of FIG. 1 according to an embodiment of the present invention is manufactured through the following process, which is only a description of one example and is not limited thereto.

First, the anode electrode 20 is formed by coating an anode electrode material on the substrate 10 . Here, as the substrate 10, a substrate generally used in this field may be used, and in particular, a glass substrate or a transparent plastic substrate excellent in transparency, surface smoothness, handling and waterproofing properties is preferable. In addition, transparent and excellent conductivity indium tin oxide (ITO), tin oxide (SnO2), zinc oxide (ZnO), etc. may be used as the material for the anode electrode formed on the substrate, but is not limited thereto.

A hole injection layer (HIL) 30 is selectively formed on the anode electrode 20 . In this case, the hole injection layer is formed through a conventional method such as vacuum deposition or spin coating. The material for the hole injection layer is not particularly limited, but CuPc (copper phthalocyanine) or IDE 406 (Idemitsu Kosan) may be used.

Then, the hole transport layer (HTL) 40 is formed on the hole injection layer 30 through a conventional method such as vacuum deposition or spin coating. As the material for the hole transport layer, in general, N, N'-diphenyl-N, N'-bis(1-naphthyl)-1,1'-biphenyl-4,4'-diamine (NPB) N, N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD), N,N'-di(naphthalen-1-yl) -N,N'-diphenylbenzidine, N,N'-di(naphthalen-1-yl)-N,N'-diphenyl-benzidine: α-NPD), etc. may be used, but in the embodiment of the present invention, and a hole transport compound according to the above-described formulas.

Next, an emission layer (EML) 50 is formed on the hole transport layer 40 . The light emitting layer forming material may include at least one selected from among phosphorescent host compounds as a light emitting host material, and may have a single layer or a multilayer structure of two or more layers. In this case, the compound of Formula 1 may be included alone or mixed with other compounds known in the art, for example, a blue light emitting dopant (iridium compound such as FIrppy or FIrpic). The phosphorescent host compound in the emission layer may be included in the range of 1 to 95% by weight based on the total weight of the materials constituting the emission layer.

The phosphorescent host compound may be formed by a vacuum deposition method, or may be deposited through a wet process such as spin coating, or laser thermal transfer (LITI) may be used.

Optionally, a hole blocking layer (HBL) that prevents excitons formed in the light emitting material from moving to the electron transport layer or prevents holes from moving to the electron transport layer 60 may be formed on the upper portion of the light emitting layer 50, The material for the hole blocking layer is not particularly limited, and a phenanthroline-based compound (eg, BCP) may be used. It can be formed through a vacuum deposition method or a spin coating method.

In addition, an electron transport layer (ETL) 60 may be formed on the emission layer 50 , and a vacuum deposition method or a spin coating method may be used. The material for the electron transport layer is not particularly limited, but TBPI or an aluminum complex (eg, Alq3 (tris(8-quinolinolato)-aluminum)) can be used.

An electron injection layer (EIL) 70 may be formed on the electron transport layer 60 by using a method such as vacuum deposition or spin coating, and the material for the electron injection layer 70 is not particularly limited, but LiF, A material such as NaCl or CsF may be used.

Then, the cathode electrode 80 is formed on the electron injection layer 70 through vacuum deposition, thereby completing the light emitting device. Here, the cathode metal includes lithium (Li), magnesium (Mg), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg). -Ag), etc. are used.

In addition, the organic light emitting device according to the present invention has a stacked structure as shown in FIG. 1 , and it is also possible to further form one or two intermediate layers, for example, a hole blocking layer, if necessary. In addition, the thickness of each layer of the light emitting device may be determined as needed within a range generally used in this field.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

Synthesis example of the hole transport compound according to the present invention

Synthesis Example 1

N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -Synthesis of diphenylbenzene-1,4-diamine

19.37 g (0.093 mol) of 9,9-dimethyl-9H-fluoren-2-amine and 11.12 g (0.116 mol) of sodium tert-butoxide were added to 250 mL of toluene, stirred for 30 minutes to completely dissolve, and then stirred at 50° C. for 1 hour. do. To the reaction solution, a solution of 0.18 g (0.31 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, the filtrate was distilled under reduced pressure, and the resulting residue was subjected to silica gel chromatography using a 1:4 mixed solution of methylene chloride and n-hexane as the eluent to obtain the target compound N ¹ -(9,9-dimethyl -9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine 12.0 g (34.3%) was obtained

Synthesis Example 2

Synthesis of N-phenylnaphthalen-1-amine

Naphthalen-1-amine and 50 g (0.35 mol) and sodium tert-butoxide 50.3 g (0.52 mol) were added to 800 mL of toluene and stirred for 30 minutes to dissolve, then 65.8 g of bromobenzene was added dropwise and stirred at 50° C. for 1 hour. To the reaction solution, a solution of 0.8 g (1.4 mmol) of bis(dibenzylideneacetone) piladium (0) in 12.1 mL (50 mmol) of tri-tert-butylphosphine was added, and then reacted at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, the filtrate was distilled under reduced pressure, and the resulting residue was subjected to silica gel chromatography using a 1:3 mixed solution of methylene chloride and n-hexane as the eluent to obtain the target compound N-phenylnaphthalen-1-amine 35.0 g (45.7%) was obtained

Synthesis Example 3

N ^One -(4-bromophenyl)-N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -Synthesis of diphenylbenzene-1,4-diamine

N ¹ -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine 9.60 g (0.021 mol) and sodium tert-butoxide 1.53 g ( 0.016 mol) was added to 300 mL of toluene, stirred for 30 minutes to dissolve, and 3.00 g (0.011 mol) of 1-bromo-4-iodobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.02 g (0.035 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21Ml (5mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, the filtrate was distilled under reduced pressure, and the resulting residue was subjected to silica gel chromatography using a 1:5 mixed solution of methylene chloride and n-hexane as the eluent to obtain the target compound N ¹ -(4-bromophenyl). )-N ¹ -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine 4.5 g (43.3%) was obtained.

Synthesis Example 4

Synthesis of 9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine

31.53 g (0.151 mol) of 9,9-dimethyl-9H-fluoren-2-amine and 18.10 g (0.188 mol) of sodium tert-butoxide were added to 1 L of toluene, stirred for 30 minutes to dissolve, and then 3-(4-bromo Phenyl)-9-phenyl-9H-carbazole 50 g (0.126 mol) was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.29 g (0.0.5 mmol) of bis(dibenzylideneacetone) philadium (0) dissolved in 3.63 mL (15 mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, and the filtrate was distilled under reduced pressure. To the obtained residue, 800 mL of n-hexane was slowly added, stirred for 6 hours, and the resulting crystals were filtered and the target compound 9,9-dimethyl-N-(4). -(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine 50g (75.6%) was obtained

Synthesis Example 5

Synthesis of N-(4-bromophenyl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine

9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine 50.0 g (0.095 mol) and sodium tert-butoxide 13.69 g (0.142 mol) was added to 1.2 L of toluene and stirred for 30 minutes to dissolve, then 34.91 g (0.123 mol) of 1-bromo-4-iodobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.22 g (0.38 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 12 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, the filtrate was distilled under reduced pressure, and the resulting residue was subjected to silica gel chromatography using a mixed solution of methylene chloride and n-hexane 1:6 as an eluent to obtain the target compound N-(4-bromophenyl). 12 g (18.5%) of -9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine was obtained.

Synthesis Example 6

Synthesis of N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine

50.0 g (0.239 mol) of 9,9-dimethyl-9H-fluoren-2-amine and 34.44 g (0.358 mol) of sodium tert-butoxide were added to 1 L of toluene, stirred for 30 minutes to completely dissolve, and then stirred at 50° C. for 1 hour. do. A solution of 0.55 g (0.96 mmol) of bis(dibenzylideneacetone) philadium (0) in 0.35 mL (1.0 mmol) of tri-tert-butylphosphine was added to the reaction solution, and then reacted at 100° C. for 16 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, the filtrate was distilled under reduced pressure, and 800 mL of n-hexane was slowly added to the obtained residue, stirred vigorously for 4 hours, and the resulting crystals were filtered and the target compound N-([1,1 62.1 g (72.0%) of '-biphenyl] -4-yl) -9,9-dimethyl-9H-fluoren-2-amine was obtained.

Synthesis Example 7

N ^One ,N ^One '-(1,4-phenylene)bis(N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ Synthesis of -diphenylbenzene-1,4-diamine)

N ¹ -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine 9.60 g (0.021 mol) and sodium tert-butoxide 1.53 g ( 0.016 mol) was added to 400 mL of toluene and stirred for 30 minutes to dissolve, then 3.00 g (0.011 mol) of 1-bromo-4-iodobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.02 g (0.034 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 12 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:5 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ ,N ¹ '-(1,4-phenylene). ) bis(N ¹ -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine) 4.5 g (43.3%) was obtained.

Synthesis Example 8

N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ^One ,N ⁴ ,N ⁴ -Synthesis of triphenylbenzene-1,4-diamine

N ¹ -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N4-diphenylbenzene-1,4-diamine 15.8 g (0.035 mol) and sodium tert-butoxide 4.04 g (0.042) mol) was added to 500 mL of toluene, stirred for 30 minutes to dissolve, and then 6.6 g (0.042 mol) of bromobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.04 g (0.07 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, and then reacted at 100° C. for 18 hours. After confirming the completion of the reaction, the resultant residue was cooled to room temperature, filtered through silica, and subjected to silica gel chromatography using a 1:5 mixed solution of methylene chloride and n-hexane as the eluent to obtain the target compound N ¹ -(9,9-dimethyl-9H-fluorene). -2-yl)-N ¹ ,N ⁴ ,N ⁴ -triphenylbenzene-1,4-diamine 10.3 g (55.8%) was obtained.

Synthesis Example 9

Synthesis of 9,9-dimethyl-N-phenyl-N-(4-(9-phenyl-9H-carbizol-3-yl)phenyl)-9H-fluoren-2-amine

18.4 g (0.035 mol) of 9,9-dimethyl-N-(4-(9-phenyl-9H-carbizol-3-yl)phenyl)-9H-fluoren-2-amine and 4.04 g of sodium tert-butoxide (0.042 mol) was added to 500 mL of toluene and stirred for 30 minutes to dissolve, then 6.6 g (0.042 mol) of bromobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.04 g (0.07 mmol) of bis(dibenzylideneacetone) philadium (0) dissolved in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, it was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound 9,9-dimethyl-N-phenyl-N-(4). 11.05 g (52.4%) of -(9-phenyl-9H-carbizol-3-yl)phenyl)-9H-fluoren-2-amine was obtained.

Synthesis Example 10

N ^One ,N ⁴ -bis(9,9-dimethyl-9H-fluoren-2-yl)-N ^One ,N ⁴ Synthesis of -bis(4-(9-phenyl-9H-carbazol-3-yl)phenyl)benzene-1,4-diamine

18.62 g (0.035 mol) of 9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine and 2.55 g of sodium tert-butoxide (0.027 mol) was added to 390 mL of toluene and stirred for 30 minutes to dissolve, then 5.00 g (0.018 mol) of 1-bromo-4-iodobenzene was added, followed by stirring at 50° C. for 1 hour. To the reaction solution, a solution of 0.04 g (0.07 mmol) of bis(dibenzylideneacetone) philadium (0) in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added, and then reacted at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, filtered through silica, and the obtained residue was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ ,N ⁴ -bis(9,9-dimethyl- 9H-fluoren-2-yl)-N ¹ ,N ⁴ -bis(4-(9-phenyl-9H-carbazol-3-yl)phenyl)benzene-1,4-diamine 9.0 g (45.1%) got

Synthesis Example 11

9,9-dimethyl-N-(4-(2-phenyl-1H-indol-1-yl)phenyl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H -Synthesis of fluoren-2-amine

2-phenyl-1H-indole 1.28 g (0.007 mol) and sodium tert-butoxide 0.95 g (0.01 mol) were added to 250 mL of toluene, stirred for 30 minutes to dissolve, and then N- (4-bromophenyl) -9,9- Dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine 4.50 g (0.007 mol) was added, followed by stirring at 50° C. for 1 hour. Tris (dibenzylideneacetone) dipalladium (0) 0.02 g (0.022 mmol) dissolved in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added to the reaction solution, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, it was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a mixed solution of methylene chloride and n-hexane 1:9 as an eluent, and the target compound 9,9-dimethyl-N-(4-(2-) 2.2 g (41.9%) of phenyl-1H-indol-1-yl)phenyl)-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine got

Synthesis Example 12

N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenyl-N ^One Synthesis of -(4-(2-phenyl-1H-indol-1-yl)phenyl)benzene-1,4-diamine

0.70 g (0.004 mol) of 2-phenyl-1H-indole and 0.52 g (0.005 mol) of sodium tert-butoxide were added to 250 mL of toluene, stirred for 30 minutes to dissolve, and then N ¹ -(4-bromophenyl)-N ¹ - (9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine 2.20 g (0.004 mol) was added, followed by stirring at 50° C. for 1 hour. A solution of tris(dibenzylideneacetone)dipalladium(0) 0.01g (0.011mmol) dissolved in 1.21mL (5mmol) tri-tert-butylphosphine was added to the reaction solution, and then reacted at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ -(9,9-dimethyl-9H-fluorene). -2-yl)-N ⁴ ,N ⁴ -diphenyl-N ¹ -(4-(2-phenyl-1H-indol-1-yl)phenyl)benzene-1,4-diamine 1.0g (38,3% ) was obtained

Synthesis Example 13

N ^One -([1,1'-biphenyl]-4-yl)-N ^One ,N ⁴ -bis(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ Synthesis of -(4-(9-phenyl-9H-carbazol-3-yl)phenyl)benzene-1,4-diamine

N-([1,1'-biphenyl]-4-yl)-9,9-dimethyl-9H-fluoren-2-amine 2.55 g (0.007 mol) and sodium tert-butoxide 0.846 g (0.009 mol) was added to 300 mL of toluene and dissolved by stirring for 30 minutes, then N-(4-bromophenyl)-9,9-dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H -Fluoren-2-amine 4.00 g (0.006 mol) was added, followed by stirring at 50° C. for 1 hour. Tris (dibenzylideneacetone) dipalladium (0) 0.02 g (0.022 mmol) dissolved in 1.21 mL (5 mmol) of tri-tert-butylphosphine was added to the reaction solution, followed by reaction at 100° C. for 18 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ -([1,1'-biphenyl]- 4-yl)-N ¹ ,N ⁴ -bis(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ -(4-(9-phenyl-9H-carbazol-3-yl)phenyl ) benzene-1,4-diamine 1.8 g (32.0%) was obtained

Synthesis Example 14

N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ^One -(4-(diphenylamino)phenyl)-N ⁴ -(naphthalen-1-yl)-N ⁴ -Synthesis of phenylbenzene-1,4-diamine

1.52 g (0.0069 mol) of N-phenylnaphthalen-1-amine and 0.83 g (0.0086 mol) of sodium tert-butoxide were added to 100 mL of toluene, stirred for 30 minutes to dissolve, and then N ¹ -(4-bromophenyl)-N ¹ 3.5 g (0.0058 mol) of -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ ,N ⁴ -diphenylbenzene-1,4-diamine was added, followed by stirring at 50° C. for 1 hour. Tris (dibenzylideneacetone) dipalladium (0) 0.02 g (0.022 mmol) dissolved in 0.61 mL (2.5 mmol) of tri-tert-butylphosphine was added to the reaction solution, followed by reaction at 100° C. for 16 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ -(9,9-dimethyl-9H-fluorene). -2-yl)-N ¹ -(4-(diphenylamino)phenyl)-N ⁴ -(naphthalen-1-yl)-N ⁴ -phenylbenzene-1,4-diamine 2,0 g (46.5%) got

Synthesis Example 15

N ^One -(9,9-dimethyl-9H-fluoren-2-yl)-N ⁴ -(naphthalen-1-yl)-N ⁴ -phenyl-N ^One Synthesis of -(4-(9-phenyl-9H-carbazol-3-yl)phenyl)benzene-1,4-diamine

3.02 g (0.014 mol) of N-phenylnaphthalen-1-amine and 1.99 g (0.021 mol) of sodium tert-butoxide were added to 150 mL of toluene, stirred for 30 minutes to dissolve, and then N- (4-bromophenyl) -9,9 -Dimethyl-N-(4-(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluoren-2-amine was added with 9.40g (0.014mol), followed by stirring at 50°C for 1 hour. . A solution of tris(dibenzylideneacetone)dipalladium(0) 0.03g (0.033mmol) in 1.21mL (5mmol) tri-tert-butylphosphine was added to the reaction solution, and then reacted at 100° C. for 16 hours. After confirming the completion of the reaction, the reaction was cooled to room temperature, and the residue obtained after silica filtration was subjected to silica gel chromatography using a 1:7 mixed solution of methylene chloride and n-hexane as an eluent to obtain the target compound N ¹ -(9,9-dimethyl-9H-fluorene). -2-yl)-N ⁴ -(naphthalen-1-yl)-N ⁴ -phenyl-N ¹ -(4-(9-phenyl-9H-carbazol-3-yl)phenyl)benzene-1,4- 3.5 g (30.9%) of diamine was obtained.

Compounds according to the above-described embodiments of the present invention may be synthesized by those skilled in the art with reference to Synthesis Examples 1 to 13.

Experimental results of the hole transporting compounds (Compounds 1 to 7) themselves synthesized according to Synthesis Examples 7 to 13

Representative physical properties of compounds 1 to 7 (Synthesis Examples 7 to 13) prepared in the above synthesis example were evaluated, and the results are shown in Table 1 below.

Properties UVmax PLmax HOMO LUMO band gap T1 TID Tg unit (nm) (nm) (eV) (eV (eV) (eV) (℃) (℃) Compound 1 (Synthesis Example 7) 308,357 432 5.1 2.19 2.91 2.51 511 132 Compound 2 (Synthesis Example 8) 333 414 5.32 2.24 3.08 2.57 342 151 Compound 3 (Synthesis Example 9) 274,335 395 5.3 2.22 3.08 2.49 443 112 Compound 4 (Synthesis Example 10) 279,359 421 5.11 2.1 3.01 2.5 537 175 Compound 5 (Synthesis Example 11) 277,305,342 396 5.45 2.41 3.04 2.49 465 139 Compound 6 (Synthesis Example 12) 332 414 5.32 2.26 3.06 2.56 357 145 Compound 7 (Synthesis Example 13) 277,292,359 423 5.16 2.09 3.07 2.5 509 156

UVmax: Absorption wavelength of material measured from spectrometer and cyclic voltammetry

PLmax: Light emission wavelength of the material measured from spectrometer and cyclic voltammetry

HOMO, LUMO, bandgap: measured from spectrometer and cyclic voltammetry

T1: Triplet energy in film form (confirmed by phosphorescence measurement at 77K)

TID: degradation temperature of the substance (verified through TGA)

Tg: glass transition temperature

As shown in Table 1, the hole transport compounds according to the embodiments of the present invention generally have a high glass transition temperature, have an advantageous HOMO energy level in hole transport, and have a high LUMO energy level. can confirm.

In addition, the materials have the advantage that they can be prepared in high yield by the above-described synthesis examples.

Experimental results of organic light emitting devices to which the hole transport compounds (Compounds 1 to 7) synthesized according to Synthesis Examples 7 to 13 were applied

comparative example

The ITO substrate was patterned so that the light emitting area had a size of 3 mm × 3 mm and then cleaned. After the substrate was mounted in a vacuum chamber, the base pressure was set to 1×10-6 torr, and a BPBPA: 3% p-dopant (10 nm)/BPBPA (35 nm) film was formed as a hole transport layer on the anode ITO, p-dopant. used Novaled's NDP-9. On the hole transport layer, an EBL layer (10 nm), DBTTP1 as a light emitting layer, and Ir(ppy) 3 as a dopant were deposited to a thickness of 30 nm with a doping concentration of 10% of the dopant. ZADN as an electron transport layer was vacuum-deposited thereon to form a film to a thickness of 35 nm, and an electron injection layer, LiF, was formed to a thickness of 1.5 nm. was evaluated and the relative changes of current, voltage, and luminance were measured in real time to evaluate the lifetime of the device, and the results are shown in Table 2 below.

The p-dopant may be TCNQ, MoO3, NDP-2, Ndp-9, or the like.

Example

The ITO substrate was patterned so that the light emitting area had a size of 3 mm × 3 mm and then cleaned. After mounting the substrate in a vacuum chamber, the base pressure was made to 1×10-6 torr, and then as a hole transport layer on the anode ITO material according to compounds 1 to 7: 3% p-dopant (10 nm) / according to compounds 1 to 7 A film was formed in the form of a material (35 nm), and NDP-9 of novaled was used as the p-dopant. On the hole transport layer, an EBL layer (10 nm), DBTTP1 as a light emitting layer, and Ir(ppy) 3 as a dopant were deposited to a thickness of 30 nm with a doping concentration of 10% of the dopant. ZADN as an electron transport layer was vacuum-deposited thereon to form a film to a thickness of 35 nm, and an electron injection layer, LiF, was formed to a thickness of 1.5 nm. was evaluated and the relative changes of current, voltage, and luminance were measured in real time to evaluate the lifetime of the device, and the results are shown in Table 2 below.

The layer structure of such a device is summarized as follows.

Comparative Example : ITO / Reference : 3% p-dopant(10nm) / Reference (35nm) / EBL (10nm) / GH : GD (30nm) / ETL (35nm) / LiF (1.5nm) / Al (200nm)

Example 1: ITO / Compound 1: 3% p-dopant (10 nm) / Compound 1 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm) )

Example 2: ITO / Compound 2: 3% p-dopant (10 nm) / Compound 2 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Example 3: ITO / Compound 3: 3% p-dopant (10 nm) / Compound 3 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Example 4: ITO / Compound 4: 3% p-dopant (10 nm) / Compound 4 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Example 5: ITO / Compound 5: 3% p-dopant (10 nm) / Compound 5 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Example 6: ITO / Compound 6: 3% p-dopant (10 nm) / Compound 6 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Example 7: ITO / Compound 7: 3% p-dopant (10 nm) / Compound 7 (35 nm) / EBL (10 nm) / GH: GD (30 nm) / ETL (35 nm) / LiF (1.5 nm) / Al (200 nm )

Device Vturn 0n (V) V (V) η _ext (%) Current efficiency (cd/A) Power efficiency (lm/W) Life (h) CIE(x,y) 1000cd Max 1000cd Max 1000cd Max LT90 3000cd comparative example 2.6 4 11.2 14.2 39.5 50.3 30.7 33.6 12.8 (0.30, 0.62) Example 1 3.2 4.7 12.9 14.7 45.7 52.2 30.4 32 8.8 (0.31, 0.62) Example 2 2.5 4 13.9 16.2 49.4 57.6 38.7 39.9 23.1 (0.30, 0.63) Example 3 2.4 3.7 11.3 15.4 40.5 55.4 34.1 40.8 16.1 (0.31, 0.62) Example 4 3 4.5 12.6 16.3 44.6 57.7 31.3 32.9 14.1 (0.30, 0.63) Example 5 3.1 4.4 10.8 14.5 37.9 51.5 27.1 31.7 10.9 (0.30, 0.62) Example 6 3.3 4.9 12.7 14.5 45 51.5 29 29.8 19.8 (0.30, 0.62) Example 7 3 4.4 13.5 15.9 47.7 56.2 33.9 35.6 12.1 (0.30, 0.63)

As shown in Table 2, the hole transport compound according to an embodiment of the present invention has a HOMO energy level that facilitates hole injection than BPBPA materials, which are conventionally commercialized materials, and has a high LUMO energy level that can block electrons. It can be confirmed that the hole transport property is excellent, so that it has high energy efficiency when applied to the hole transport layer of the organic light emitting device. In particular, the device using the hole transport compound according to the embodiment of the present invention has a considerably low driving voltage. confirmed that there is.

As described above, the best embodiment has been disclosed in the drawings and the specification. The present invention is not limited to the above-described embodiments, and various changes and modifications may be made by those skilled in the art within the scope not departing from the spirit of the present invention, and the true technical protection of the present invention The scope should be defined by the spirit of the appended claims.

10: substrate
20: anode electrode
30: hole injection layer
40: hole transport layer
50: light emitting layer
60: electron transport layer
70: electron injection layer
80: cathode electrode

Claims (7)

A hole transport compound represented by Formula 1 below:
[Formula 1]

In Formula 1,
wherein R1, R2, and R3 are each independently phenyl, naphthyl, triphenylamine, a phenyl-phenylcarbazole derivative, or a fluorene derivative;
At least one of R1, R2, and R3 comprises triphenyl amine, a phenyl-phenylcarbazole derivative.
The method according to claim 1,
A hole transport compound represented by the following formula:

A hole transport compound represented by the following formula (2):
[Formula 2]

Wherein R4 is triphenylamine, or a phenyl-phenylcarbazole derivative, a hole transport compound.
4. The method according to claim 3,
A hole transport compound represented by the following formula:

A hole transport compound represented by the following formula (3):
[Formula 3]

Wherein R5 is triphenylamine, or a phenyl-phenylcarbazole derivative, a hole transport compound.
6. The method of claim 5,
A hole transport compound represented by the following formula:

In the organic light emitting device comprising a hole transport layer between a pair of electrodes,
The organic light-emitting device, characterized in that the hole transport layer comprises the hole transport compound according to any one of claims 1 to 6.

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