KR20170134073A - Hole transporting material and organic light emitting diodes using the same - Google Patents

Abstract

The present invention relates to a novel hole transfer material for organic light-emitting devices, and an organic light-emitting device using the same. More specifically, the present invention relates to a novel hole transfer material for organic light-emitting devices. By producing the hole transfer material via a Suzuki coupling reaction or a Buchwald-Hartwig coupling reaction using a carbazole derivative and a naphthalene derivative, the hole transfer material exhibits outstanding properties in terms of thermal stability, color purity, and luminous efficiency, thereby being applicable to organic light-emitting devices requiring high temperature and long lifespan. The present invention further relates to an organic light-emitting device using the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a hole transporting material for an organic light emitting device, and an organic light emitting device using the hole transporting material and organic light emitting diodes using the same.

The present invention relates to a novel hole transporting material for organic light emitting devices and an organic light emitting device using the same. More particularly, the present invention relates to a hole transporting material for organic light emitting devices, and more particularly to a hole transporting material for a hole transporting material, ) Coupling reaction, and an organic light emitting device using the same.

In the information society based on the development of IT technology, fast and accurate information transmission and acquisition are important, which leads to the demand and development of a display device capable of realizing effective information utilization.

As the IT industry develops, the desire to collect information anytime and anywhere increases, as seen in smartphones that have been experiencing explosive increase in demand in recent years. As a result, the display becomes easier and more responsive and portable Became essential. What is emerging for this is OLED (Organic Light-Emitting Diode).

Recently, materials research for OLED for solution process in the process of manufacturing organic light-emitting diode (OLED) has attracted attention as a next generation display technology when not only a polymer material but also a low molecular material capable of solution process is used.

Most organic materials in a pixel are easily dissolved in an organic solvent. A lot of researches have been actively made on a method of printing pixels by solubilizing organic matters using these characteristics. Most of the printing process, as seen in newspapers or large prints, has a relatively high precision in a large area, and a high level of control is possible so that various colors can be mixed.

The solution process facilitates large-scale surface preparation at a lower cost than the vacuum deposition. The major difference between the vacuum deposition and the solution process in fabricating the OLED device is how to implement a multi-layered structure.

In order to accomplish this, a low-molecular organic material is essential because organic materials using a low-molecular material are more advantageous than a polymer. Injection and migration of electrons and holes in organic materials are important factors for determining the efficiency and lifetime of an OLED. The role of the hole transport layer material is very important.

 Therefore, the development of organic materials for transporting low molecular weight holes capable of solution processing is a key point of improving the performance of OLED devices.

The HOMO level of the hole transport layer should be higher than the HOMO level of the light emitting layer to easily transport the holes and to excite the electrons to the emission region, It is possible to increase the hole mobility and prevent the efficiency reduction. In addition, a high purity, high thermal stability having a high glass transition temperature (Tg) of 100 DEG C or more is required. In general, an aromatic amine compound containing an electron donating group and capable of stabilizing a cation radical generated when holes are injected Mainly used.

In addition, it is very important to use a material having a triplet exciton's triplet energy of 2.4 eV or more in the hole transport layer. If the triplet energy of the hole transport layer is lower than that of the light emitting layer, the triplet exciton has a triplet energy, The efficiency of the device is reduced due to the diffusion of electrons.

It is generally known that carbazole derivatives among organic compounds have excellent hole mobility and triplet state. Therefore, if a carbazole derivative is used as an organic material that can be used for a hole transport layer, hole transport characteristics and triplet characteristics can be improved.

Korean Patent No. 10-0289059

In the present invention, the present invention has been completed by examining the reactivity of a carbazole derivative having a high hole mobility and a high triplet state as an organic material usable for a hole transport layer.

Accordingly, it is an object of the present invention to provide a novel hole transport material for an organic light emitting device which is excellent in thermal stability, color purity and optical efficiency, and which is suitable for an organic light emitting device requiring a high temperature and a long lifetime, and an organic light emitting device using the same. The purpose.

In order to achieve the above object, the present invention provides a carbazole derivative for a hole transport material of an organic electroluminescent device, which is represented by any one of Chemical Formulas 1 to 4:

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

.

.

The present invention also provides a process for producing a hole transporting material for an organic light emitting device, which is represented by any one of the above-mentioned formulas (1) to (4), wherein a carbazole derivative and a naphthalene derivative are subjected to a Suzuki coupling reaction or a Buchwald- Hartwig coupling reaction A process for producing a carbazole derivative is provided.

Also, the present invention provides an organic light emitting device comprising a hole transporting material represented by any one of Chemical Formulas 1 to 4 in a hole transporting layer.

According to the present invention, there can be provided a novel hole transporting material for organic light emitting devices which exhibits excellent properties in terms of thermal stability, color purity and optical efficiency. Such hole transporting materials are used in organic light emitting devices requiring high temperature and long lifetime The current efficiency, power efficiency and lifetime characteristics can be improved as compared with the conventional organic electroluminescent devices.

1 is a graph showing a ¹ H NMR spectrum of a hole transport material (compound of Formula 4) prepared according to an embodiment of the present invention.
2 is a graph showing the IR spectrum of a hole transport material (compound of Formula 4) for an organic light emitting device manufactured according to an embodiment of the present invention.
FIG. 3 is a graph showing the result of UV-vis spectrum measurement of a hole transporting material for an organic light emitting device manufactured according to an embodiment of the present invention.
FIG. 4 is a graph showing the results of PL spectra of a hole transporting material for an organic light emitting device manufactured according to an embodiment of the present invention at room temperature and low temperature (77K).
FIG. 5 is a graph showing a result of cyclic voltammetry measurement for a hole transporting material for an organic light emitting device manufactured according to an embodiment of the present invention. FIG.
6 is a view illustrating the structure of an organic light emitting device manufactured using a hole transporting material for an organic light emitting device according to an embodiment of the present invention.
7 is a graph showing the JVL and L-efficiency measurement results of an organic light emitting device manufactured using a hole transporting material for an organic light emitting device manufactured according to an embodiment of the present invention.
8 is a graph showing the results of EL spectrum measurement of an organic light emitting device manufactured using a hole transporting material for an organic light emitting device according to an embodiment of the present invention.
7a of the present invention refers to a compound represented by the general formula (1) of the present invention, 7b represents a compound represented by the general formula (2) of the present invention, and 7c represents a compound represented by the general formula (3) of the present invention.

Hereinafter, the present invention will be described in detail.

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Repeated descriptions of the same technical constitution and operation as those of the conventional art will be omitted.

The present invention provides a carbazole derivative for a hole transport material of an organic electroluminescent device represented by any one of Chemical Formulas 1 to 4 below.

[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

The organic light-emitting material for organic light emitting devices represented by any one of Chemical Formulas 1 to 4 may be prepared by synthesizing a carbazole derivative and a novel hole transporting material having a naphthalene derivative introduced thereinto, thereby obtaining thermal stability, color purity, Can be improved.

Specifically, the carbazole derivative for a hole transport material of the organic electroluminescent device of the present invention is a 9-hexyl-N, N'-di (naphthalene-1-yl) -N, N'- 3,6-diamine (9-Hexyl- N, N ' -di (naphthalen-1-yl) - N, N' -diphenyl-9 H -carbazole-3,6-diamine), 9- hexyl of formula (II) -N, N'- di (naphthalene-3-yl) -N, N'- diphenyl -9H- carbazole-3,6-diamine (9-Hexyl- N, N ' -di (naphthalen-3-yl ) - N, N '-diphenyl- 9 H -carbazole-3,6-diamine), of the formula 3 N, N'- di (naphthalene-1-yl) -N, N'-9- triphenyl -9H- 9-triphenyl-9H-carbazole-3,6-diamine), 9-hexyl-3,6-diamine of formula (4) N, N'- di (naphthalene-1-yl) -N, N'- di (naphthalene-3-yl) -9H- carbazole-3,6-diamine (9-Hexyl- N, N ' -di ( naphthalen-1-yl) -N, N' -di (napthalen-3-yl) -9H - carbazole-3,6-diamine).

The present invention also relates to a method for producing a hole transporting material for a organic electroluminescent element hole transporting material represented by any one of Chemical Formulas 1 to 4 wherein a carbazole derivative and a naphthalene derivative are subjected to a Suzuki coupling reaction or a Buchwald-Hartwig coupling reaction, A method for preparing a sol derivative is provided.

The carbazole derivative includes 9-hexyl-3,6-diiodo-9H-carbazole represented by the following general formula (5), 3,6-dibromo-9H-carbazole represented by the following general formula (6), phenylcarbazole derivative , A diphenylcarbazole derivative, a naphthylcarbazole derivative, and the like. In particular, 9-hexyl-3,6-diiodo-9H-carbazole represented by the following general formula (5) -Dibromo-9H-carbazole is preferably used.

[Chemical Formula 5]

[Chemical Formula 6]

The naphthalene derivatives include N-phenylnaphthalene-1-amine represented by the following general formula (7), N-phenylnaphthalene-2-amine represented by the following general formula (8) Phenyl naphthalene-1-amine represented by the following general formula (7), a compound represented by the following general formula (8): ???????? Phenyl naphthalene-2-amine represented by the following formula (9) or 4- (N- (naphthalene-1-yl) -N Do.

(7)

[Chemical Formula 8]

[Chemical Formula 9]

The carbazole derivative and the naphthalene derivative may be subjected to a Suzuki coupling or a Bukwald-Hartwig coupling reaction under a palladium catalyst to prepare the hole transporting material for an organic light emitting device of the present invention.

It is a matter of course that the Suzuki coupling or the Bugwald-Hartweck coupling reaction can be carried out according to a conventional method practiced in the art. Specifically, after the carbazole derivative, the naphthalene derivative and the catalyst are mixed, an organic solvent and a catalyst are added under a nitrogen atmosphere, and the reaction is carried out at 90 to 120 ° C for 20 to 40 hours, preferably at 100 ° C for 24 to 36 hours . Next, the reaction product was extracted with NaCl saturated solution and MC, and then the organic layer was separated, dried with MgSO ₄ , filtered and concentrated to obtain the hole transporting material for organic light emitting devices represented by any one of Chemical Formulas 1 to 4 of the present invention .

The catalyst may be a catalyst such as Pd, Cu, Sn or the like used in a Suzuki coupling or a Buwald-Hartweek coupling reaction. In particular, Pd (Ph ₃ P) ₄ , Pd (OAc) ₂ < / RTI > palladium catalysts may be used Examples of the organic solvent include, but are not limited to, toluene, water, chloroform, tetrahydrofuran, dioxalic acid, and the like.

Also, the present invention provides an organic light emitting device comprising the hole transporting material represented by any one of formulas (1) to (4) of the present invention as described above as a hole transporting layer. The hole transporting material represented by any one of Chemical Formulas 1 to 4 may be used in a hole transporting layer of an organic light emitting device to improve current efficiency, power efficiency, and lifetime characteristics.

The organic electroluminescent device includes a first electrode, a second electrode, and at least one organic material layer interposed between the first electrode and the second electrode. The organic material layer includes the electron transport material represented by the general formulas (1) to (4) And an electron transport layer including the electron transport layer.

The organic material layer may include a hole injection layer, a hole transport layer, a light emitting layer, and an electron injection layer.

Specifically, the organic electroluminescent device is formed by coating an anode material as a first electrode on an upper portion of a lower substrate.

The substrate is preferably a glass substrate, an organic substrate, or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness.

The anode material used as the first electrode is a metal film that is a reflective film in the case of a top emission structure, and a transparent and highly conductive indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide ₂ ), zinc oxide (ZnO) or the like is used. Thereafter, an insulating film (PDL) defining a pixel region is formed.

After forming an insulating film, a hole injecting layer and / or a hole transporting layer are stacked over the entire substrate with an organic film.

The hole injection layer material may be selectively deposited on the anode by vacuum thermal deposition or spin coating to form a hole injection layer (HIL). The hole injection layer material is not particularly limited, and copper phthalocyanine (CuPc) or starburst type amines such as TCTA, m-MTDATA, and IDE406 (Idemitsu Materials) can be used.

A hole transport layer (HTL) is formed on the hole injection layer by vacuum thermal deposition or spin coating on the hole transport layer material, that is, the hole transport material represented by any of formulas 1 to 4 of the present invention. At this time, it is more preferable that the hole transporting layer is formed to have a thickness of about 50 to 1,500 angstroms in terms of hole transporting characteristics and driving voltage characteristics.

Then, a red light emitting material, a green light emitting material, and a blue light emitting material are patterned in the R and G regions of the pixel region to form a light emitting layer (EML) as a pixel region. The light emitting layer forming method is not particularly limited, but a vacuum deposition method, an ink jet printing method, a laser transfer method, and a photolithography method may be used.

An electron injection layer (EIL) may be selectively deposited on the electron transport layer. The electron injection layer material is not particularly limited, and materials such as LiF, NaCl, CsF, Li ₂ O, BaO, and Liq can be used.

Subsequently, a metal for a cathode, which is a second electrode, is deposited on the electron injection layer by vacuum thermal deposition, and the cathode, which is the second electrode, is coated over the entire surface of the substrate and sealed to complete the organic electroluminescent device. The cathode metal may be Li, Mg, Al, Al-Li, Ca, Mg-In, Mg-Ag, ) May be used.

Hereinafter, the present invention will be described in more detail with reference to examples. These embodiments are for purposes of illustration only and are not intended to limit the scope of protection of the present invention.

Example 1 Preparation of 9-hexyl-N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-9H-carbazole-3,6-

1-1. Preparation of 9-hexyl-3,6-diiodo-9H-carbazole

[Reaction Scheme 1]

After refluxing was carried out in 250 mL of a dried two-necked flask, ₃ g ( ₁ eq) of 9 H -carbazole, 2.7 g (0.7 eq) of KIO ₃ , 3.88 g (1.3 eq) of KI and a magnetic bar were put in a vacuum state, and nitrogen was filled using a nitrogen balloon. As a solvent, 50 mL of AcOH was dissolved by using a syringe, and the mixture was heated to 80 캜 with stirring in an oil bath. After 4 hours, the reaction mixture was cooled at room temperature, washed with AcOH, filtered and separated with a small amount of H ₂ O and MeOH, and then dried to obtain 5.36 g of an ivory solid product, 3,6-diiodo-9H-carbazole Yield: 72%).

20 g (1 eq) of the prepared 3,6-diiodo-9H-carbazole, 6.44 g (1.2 eq) of t-BuOK and a magnetic bar were added to 250 mL of the dried single-necked flask, And filled with nitrogen. As a solvent, 100 mL of DMF was added to the solution using a syringe, and the mixture was stirred for 2 to 3 minutes. Then, 8.04 mL (1.2 eq) of C ₆ H ₁₃ Br was added slowly using a syringe. The reaction mixture was allowed to stand at room temperature for one night. After completion of the reaction, the mixture was extracted with EA and H ₂ O. At this time, DMF was removed by extraction with H ₂ O more than 5 times to remove DMF. The remaining water was then completely removed using MgSO ₄ , filtered and separated, and then evaporated to dryness. Subsequently, purification was carried out by chromatography using n-hexane as an eluent to obtain 21.46 g of 9-hexyl-3,6-diiodo-9H-carbazole as an ivory solid product (yield: 90%).

1-2. N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-9H-carbazole-3,6-diamine

[Reaction Scheme 2]

9-hexyl-N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-9H-carbazole-3,6-diamine was prepared according to Reaction Scheme 2 above. First, a reflux device was installed in 250 mL of a dried two-necked flask, and then 2 g (2.5 eq) of 9-hexyl-3,6-diiodo-9H-carbazole and 2.18 g (0.1 eq) of Pd (OAc) ₂ and a magnetic bar were filled in a nitrogen atmosphere using a nitrogen balloon. As a solvent, 100 mL of dry-toluene was added to dissolve using a syringe, and the mixture was stirred while heating at 100 캜 using an oil bath. 0.56 mL (0.3 eq) of t-Bu ₃ P was slowly added to the reaction solution using a syringe, and 6 mL of 2M NaOt-Bu was added slowly using a syringe. After 24 hours, the reaction mixture was cooled at room temperature, extracted with NaCl saturated solution and MC, and the organic layer was separated. The remaining water was completely removed using magnesium sulfate (MgSO ₄ ), filtered, separated and evaporated to dryness . Subsequently, the product was separated and purified by chromatography using n-hexane: MC (10: 1) as eluent to obtain 9-hexyl-N, N'-di (naphthalen- N'- diphenyl -9H- carbazol-3,6-diamine (9-Hexyl- N, N ' -di (naphthalen-1-yl) - N, N' -diphenyl-9 H -carbazole-3,6 -diamine, 2g (yield: 73%) of the formula (1).

_{^{1 H NMR (500MHz, CDCl 3}} ) δ8.11-8.09 (d, J = 8.5Hz, 3H), 7.90-7.89 (d, J = 8Hz, 3H), 7.75-7.73 (d, J = 8Hz, 3H) , 7.48-7.45 (t, J = 8Hz , 5H), 7.41-7.30 (m, 7H), 7.17-7.14 (t, 4H), 6.87-6.86 (d, J = 7.5Hz, 5H), 4.1 (m, 2H), 1.88 (t, J = 7.5 Hz, 2H), 1.50-1.25 (m, 9H);

_{^{13 C NMR (125MHz, CDCl 3}} ) δ140.4, 139.3, 135.3, 129.0, 128.4, 128.1, 126.6, 126.5, 126.4, 126.3, 126.2, 126.1, 125.8, 124.7, 120.7, 119.5, 109.5, 108.5, 33.6, 31.7 , 27.1, 22.6, 14.1, 10.9; GC-MS: 686.35.

Example 2. Preparation of 9-hexyl-N, N'-di (naphthalene-3-yl) -N, N'-diphenyl-9H-carbazole-

[Reaction Scheme 3]

9-hexyl-N, N'-di (naphthalene-3-yl) -N, N'-diphenyl-9H-carbazole-3,6-diamine was prepared according to Reaction Scheme 3 above. First, a reflux apparatus was installed in 250 mL of a dried two-necked flask, and then 2.2 g (2.5 eq) of 9-hexyl-3,6-diiodo-9H-carbazole and 2.2 g (2.5 eq), Pd (OAc) _{2 and} 0.1 g (0.1 eq) of Pd (OAc) ₂ and a magnetic bar were charged and nitrogen was charged using a nitrogen balloon. As a solvent, 100 mL of dry-toluene was added to dissolve using a syringe, and the mixture was stirred while heating at 100 캜 using an oil bath. 0.56 mL (0.3 eq) of t-Bu ₃ P was slowly added to the reaction solution using a syringe, and 6 mL of 2M NaOt-Bu was added slowly using a syringe. After 24 hours, the reaction mixture was cooled at room temperature, extracted with NaCl saturated solution and MC, and the organic layer was separated. The remaining water was completely removed using magnesium sulfate (MgSO ₄ ), filtered, separated and evaporated to dryness . Subsequently, the product was separated and purified by chromatography using n-hexane: MC (8: 1) as eluent to obtain 9-hexyl-N, N'-di (naphthalene- N'- diphenyl -9H- carbazol-3,6-diamine (9-Hexyl- N, N ' -di (naphthalen-3-yl) - N, N' -diphenyl-9 H -carbazole-3,6 -diamine (Formula 2) 1.8 g (yield: 66%) was obtained.

_{^{1 H NMR (500MHz, CDCl 3}} ) δ7.82 (s, 2H), 7.75-7.73 (d, J = 8.5Hz, 2H), 7.70-7.68 (d, J = 9Hz, 2H), 7.56-7.54 (d , J = 8Hz, 2H), 7.30-7.40 (m, 16H), 7.26-7.23 (t, J = 8 Hz, 4H), 7.16-7.14 (d, J = 7.5Hz, 2H), 4.2 (t, J = 7.5 Hz, 2H), 1.9 (m, 2H), 1.50-1.25 (m, 9H);

_{^{13 C NMR (125MHz, CDCl 3}} ) δ139.5, 134.5, 129.5, 129.3, 129.1, 128.6, 128.2, 127.5, 127.1, 126.8, 126.2, 125.9, 124.9, 124.0, 123.6, 123.5, 123.4, 122.9, 122.2, 121.8 , 120.0, 109.8, 33.6, 31.6, 27.1, 22.6, 14.1, 10.9; GC-MS: 686.28.

Example 3 Preparation of N, N'-di (naphthalen-1-yl) -N, N'-9-triphenyl-9H-carbazole-

[Reaction Scheme 4]

N, N'-di (naphthalen-1-yl) -N, N'-9-triphenyl-9H-carbazole-3,6-diamine was prepared according to Reaction Scheme 4 above. First, a reflux condenser was installed in 250 mL of a dried two-necked flask, and then 2 g (1 eq, purchased from Sigma-Aldrich Korea) of 3,6-dibromo-9H-carbazole and 2.18 g ), 0.1 g (0.1 eq) of Pd (OAc) ₂ and a magnetic bar were charged and nitrogen was charged using a nitrogen balloon. As a solvent, 100 mL of dry-toluene was added to dissolve using a syringe, and the mixture was stirred while heating at 100 캜 using an oil bath. 0.56 mL (0.3 eq) of t-Bu ₃ P was slowly added to the reaction solution using a syringe, and 6 mL (3 eq) of 2M NaOt-Bu was added slowly using a syringe. After 36 hours, the reaction mixture was cooled at room temperature, and extracted with NaCl saturated solution and MC. The organic layer was separated and the remaining water was completely removed using magnesium sulfate (MgSO ₄ ), filtered, separated and evaporated to dryness . Subsequently, the product was separated and purified by chromatography using n-hexane: MC (10: 1) as eluent to obtain N, N'-di (naphthalen-1-yl) -N, -Naphthalene-1-yl) -N, N'-9-triphenyl-9H-carbazole-3,6-diamine, ) (Yield: 73%).

_{^{1 H NMR (500MHz, CDCl 3}} ) δ8.08-8.06 (d, J = 8.5Hz, 2H), 7.89-7.88 (d, J = 8Hz, 2H), 7.8 (s, 2H), 7.74-7.73 (d , J = 8Hz, 2H), 7.60-7.55 (q, J 1 = 7.5Hz, J 2 = 15.5Hz, 4H), 7.47-7.44 (m, 5H), 7.37-7.34 (q, J 1 = 7.5Hz, J ₂ = 14 Hz , 4H), 7.31-7.25 (m, 4H), 7.16-7.13 (t, J = 8 Hz, 4H), 6.89-6.84 (q, J ₁ = 8 Hz, J ₂ = 17 Hz, 6H);

_{^{13 C NMR (125MHz, CDCl 3}} ) δ183.6, 179.2, 171.3, 168.4, 160.1, 159.7, 141.5, 135.3, 129.0, 128.4, 128.2, 127.5, 127.2, 126.8, 126.0, 125.0, 124.6, 120.5, 119.7, 110.7 ; GC-MS: 668.23.

Example 4. Synthesis of 9-hexyl-N, N'-di (naphthalen-1-yl) -N, N'- Produce

[Reaction Scheme 5]

N, N'-di (naphthalene-3-yl) -9H-carbazole-3,6-diamine was prepared according to the above reaction scheme 5 . First, a reflux apparatus was installed in 250 mL of a dried two-necked flask, and then 1 g (1 eq) of 9-hexyl-3,6-diiodo-9H-carbazole and 4- (N- (naphthalen- (3 eq), Pd (Ph ₂ P) _{4, and} 0.46 g (0.2 eq) of N- (naphthalen-3-yl) amino) phenylboronic acid and a magnetic bar were placed in a vacuum state. Lt; / RTI > As a solvent, 50 mL of dry-toluene was added by using a syringe to dissolve, and the mixture was stirred while being heated to 100 캜 using an oil bath. To the reaction was slowly added 25 mL of K ₂ CO ₃ using a syringe. After 24 hours, the reaction mixture was cooled at room temperature, extracted with NaCl saturated solution and MC, and the organic layer was separated. The remaining water was completely removed using magnesium sulfate (MgSO ₄ ), filtered, separated and evaporated to dryness . Subsequently, the product was separated and purified by chromatography using n-hexane: MC (8: 1) as an eluent to obtain 9-hexyl-N, N'-di (naphthalen- '- di (naphthalene-3-yl) -9H- carbazole-3,6-diamine (9-Hexyl- N, N' -di (naphthalen-1-yl) - N, N '-di (napthalen-3 -yl) -9H - carbazole-3,6-diamine (Formula 4) 0.85 g (yield: 46%) was obtained.

¹ H NMR spectra of 9-hexyl-N, N'-di (naphthalen-1-yl) -N, N'-di (naphthalen- The results are shown in FIG. 1, and the IR spectrum results are shown in FIG.

Experimental Example 1. Analysis of thermal and optical physical properties

UV spectroscopy, PL spectroscopies, cyclic voltammetry (VC) and HOMO-LUMO energy levels were measured using the compounds represented by formulas 1 to 4 prepared in Examples 1 to 4, Are shown in Table 1 and Figs. 3 to 5 below.

division T _g / T _d
(° C) UV? _Max
(nm) PL λ _max
(nm) HOMO
(eV) LUMO
(eV) T ₁
(eV) E _g
(eV) Formula 1 90/400 279,351 470 -5.16 -2.22 2.40 2.94 (2) 86/380 388,316 435 -5.47 -2.19 2.42 2.95 (3) 120/200 304,353 454 -5.06 -2.05 2.35 3.01 Formula 4 126/504 - - -5.04 -1.99 2.36 3.05

As shown in Table 1, the T _d (° C) value of the carbon derivative for the hole transporting material represented by the general formulas (1) to (4) prepared in Examples 1 to 4 was 200 ° C or more, It was acid-derivative of 4 is very high as more than 380 ℃, was T _g (℃) values also appeared to 90, 86, 120, 126 ℃ respectively, the HOMO, LUMO value was suitable for use as a hole transport layer.

3 to 5 show UV-vis, photoluminescence (PL) spectra and cyclic voltammetry (CV) measurements for the photophysical properties of the compounds represented by formulas 1 to 3 prepared in Examples 1 to 3 The results are shown.

UV-vis spectral results As shown in Fig. 3, the compounds represented by formulas (1) to (3) showed maximum absorption peaks at 279/351, 277/316 and 304/353 nm. In particular, the first peak of the compound represented by the formula (3) showed an absorption peak of the long wavelength unlike the compound of the formula (1) or (2) due to the phenyl group bonded to the N position of the carbazole. Thus, the absorption peaks of Formulas 1 to 3 were completely transparent in the visible light region. On the other hand, the UV absorption spectrum of the compound represented by Chemical Formulas 1 to 3 was 2.94. 295, and 3.01 eV, respectively, corresponding to the energy band gaps at 422, 420, and 412 nm, respectively.

(PL) spectrum at room temperature and low temperature (77K) As shown in FIG. 4, the PL spectra of the compounds represented by formulas (1) to (3) were observed at 470, 435 and 454 nm, respectively. The triplet energies were calculated from the PL spectral emission. As a result, the triplet energy values of the compounds represented by Formulas 1 to 3 were 2.40, 2.42, and 2.35 eV, respectively, and values similar to MPB (2.40 eV) Respectively.

The cyclic voltammetry (CV) was also measured to investigate the electrochemical behavior of the compounds of formulas (1-3). As a result of the cyclic voltammetry measurement, the HOMO values of the compounds represented by Chemical Formulas 1 to 3 were -5.16, -5.14, and -5.06 eV, respectively, as shown in FIG. 5, which was higher than the general hole transporting material NPM (-5.40 eV) . From these results, it was found that the hole transporting material for organic light emitting devices of the present invention having a high HOMO value would be advantageous for improving the hole injection property. The LUMO values of -2.22, -2.19, and -2.05 eV, respectively, were found to be effective in blocking electron escape from EML.

Meanwhile, although not shown in FIGS. 3 to 5, the compound represented by Formula 4 prepared in Example 4 of the present invention has a PL value of 433 nm, a UV-vis value of 333 nm, a HOMO value of 5.04 eV, a LUMO value the 2.36eV, T ₁ values showed the physical properties of 2.36eV, T _g values showed the thermal properties 125.62 ℃, T _d value is 504.05 ℃.

Experimental Example 2. Evaluation of device characteristics

In order to evaluate the hole-aqueous properties of the compounds of Formulas 1 to 3 prepared in Examples 1 to 3, ITO (150 nm) / HATCN (10 nm) / HTL (30 nm) / Bebq2 : Ir (mphmq) 2 (tmd) [5%] (20 nm) / Bphen (40 nm) / LiF (2 nm) / Al (100 nm). The J-V-L and L-efficiency characteristics of the organic light emitting device prepared above are shown in Table 2 and FIG. The EL spectrum of the organic light emitting device is shown in Fig.

As shown in FIG. 7, the compounds of the formulas (1) to (3) prepared in Examples 1 to 3 showed current density, brightness, voltage efficiency and current efficiency similar to those of NPB which is a general hole transporting material. And 2 showed device performance more similar to NPB. 8 shows the results of EL spectroscopy, and it was confirmed that the compounds of the formulas (1) to (3) exhibited a typical luminescent color of the luminescent material.

From these results, the compounds of the formulas (1) to (4) according to the present invention show optimum performance, which means that they are promising as a hole transport material.

Although the present invention has been described in terms of the preferred embodiments mentioned above, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. It is also to be understood that the appended claims are intended to cover such modifications and changes as fall within the scope of the invention.

Claims (8)

A carbazole derivative for a hole transport material of an organic electroluminescent device represented by any one of the following formulas (1) to (4):
[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

. A carbazole derivative for a hole transport material of an organic electroluminescent element represented by any one of the following Chemical Formulas 1 to 4 wherein a carbazole derivative and a naphthalene derivative are subjected to a Suzuki coupling reaction and a Buchwald-Hartwig coupling reaction Manufacturing method:
[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

. 3. The method of claim 2,
The carbazole derivative may be 9-hexyl-3,6-diiodo-9H-carbazole, 3,6-dibromo-9H-carbazole (3 , 6-dibromo-9H-carbazole), a phenylcarbazole derivative, a diphenylcarbazole derivative, and a naphthylcarbazole derivative. The method for producing a carbazole derivative for a hole transport material of an organic light emitting device, 3. The method of claim 2,
The naphthalene derivative may be a 4- (N- (naphthalen-1-yl) -N- (naphthalen-3-yl) amino) 3-yl) amino) phenylboronic acid, N-phenylnaphthalen-1-amine, N-phenylnaphthalen-2-amine, And phenyl naphthalene. The method for producing a carbazole derivative for a hole transport material according to any one of claims 1 to 7, 3. The method of claim 2,
Wherein the Suzuki coupling reaction is carried out at 90 to 120 ° C for 20 to 40 hours in the presence of a catalyst. 3. The method of claim 2,
Wherein the Bukwald-Hartwig coupling reaction is carried out at 90 to 120 ° C for 20 to 40 hours under a catalyst. The method according to claim 5 or 6,
Wherein the catalyst is at least one selected from the group consisting of Pd, Cu, and Sn. An organic light emitting device comprising a hole transporting material represented by any one of the following formulas (1) to (4) in a hole transporting layer:
[Chemical Formula 1]

(2)

(3)

[Chemical Formula 4]

.

Images