KR101631507B1 - Hole transporting material and organic light emitting diodes using the same - Google Patents

Abstract

The present invention relates to a novel hole transport material for organic electroluminescent devices and an organic electroluminescent device using the same. More particularly, the present invention relates to a hole transport material for a 4- (9H-carbazol-9-yl) triphenylamine derivative and a hole transporting moiety To a hole transporting material for an organic electroluminescence device synthesized by a Suzuki coupling reaction and an organic electroluminescence device using the same.
The hole transporting material for an organic electroluminescence device of the present invention is suitable for application to an organic electroluminescence device having a high glass transition temperature, excellent thermal and morphological stability, excellent hole transporting property, and high temperature and long lifetime Do.

Description

TECHNICAL FIELD The present invention relates to a hole transporting material for organic electroluminescent devices and an organic electroluminescent device using the same,

The present invention relates to a novel hole transport material for organic electroluminescent devices and an organic electroluminescent device using the same. More particularly, the present invention relates to a hole transport material for a 4- (9H-carbazol-9-yl) triphenylamine derivative and a hole transporting moiety To a hole transporting material for organic electroluminescent devices synthesized by a Suzuki coupling reaction and an organic electroluminescent device using the same.

Organic light-emitting diodes (OLEDs) have been growing in popularity over the past few years due to their low cost, full color and flat panel display characteristics. Accordingly, various methods have been developed to improve the efficiency and performance of the organic electroluminescent device.

The main cause of the decrease in the performance of the organic electroluminescent device is the morphological change of the amorphous organic layer, especially the transport layer. This change is caused by Joule heating during operation of the organic electroluminescent device. Therefore, the need for an amorphous material having a high resistance to heat and a high glass transition temperature (Tg) is increasingly urgent. Therefore, in order to produce an organic electroluminescent device having thermal stability, it is necessary to develop various methods for synthesizing a hole transporting material (HTMs) having a high glass transition temperature.

On the other hand, it is known that triphenylamine and carbazole having a strong electron cycle have an excellent water-base property and act as an important part of a major transportation material. The weak thermal stability of triphenylamine has a lower electron cycle than the diphenylamine moiety, but thermal stability can be greatly improved when a stable and stable carbazole moiety is bonded to such triphenylamine. Therefore, bonding of triphenylamine and carbazole can improve the thermal stability and the transportation characteristics of the majors.

Korean Patent No. 10-1002733

In order to solve the problems of the prior art as described above, the present invention provides a hole transport material for an organic electroluminescent device having a high glass transition temperature, excellent thermal and morphological stability, and excellent hole transporting property, and an organic electroluminescent device And to provide the above-mentioned objects.

Another object of the present invention is to provide a hole transporting material for an organic electroluminescence device which is suitable for application to an organic electroluminescence device requiring a high temperature and a long lifetime, and an organic electroluminescence device using the same.

It is another object of the present invention to provide a hole transport material for an organic electroluminescent device and an organic electroluminescent device using the same, which can improve current efficiency, power efficiency and lifetime characteristics as compared with conventional organic electroluminescent devices.

In order to achieve the above object, the present invention provides a hole transport material for an organic electroluminescence device,

상기 화학식 1의 식에서, [Chemical Formula 1]

In the formula (1)

,

또는

이다.R is

,

or

to be.

delete

delete

The present invention also provides a method for producing a hole for an organic electroluminescence device represented by Formula 1, which comprises subjecting a 4- (9H-carbazol-9-yl) triphenylamine derivative and a bromoaryl derivative to a Suzuki coupling reaction A method for producing a transport material is provided.

The 4- (9H-carbazol-9-yl) triphenylamine derivative is obtained by reacting 9- (4- (diphenylamino) phenyl) -9H- carbazol- (diphenylamino) phenyl) may be used -9 H -carbazol-2-yl- 2-boronic acid).

The bromoaryl derivative can be obtained by reacting N, N-bis ([1,1'-biphenyl] -4-yl) -biphenyl] -4-yl) [1,1'-biphenyl] -4-amine, bis-biphenyl-4-yl- (4'-bromobiphenyl- 4-yl- (4'-bromobiphenyl-4-yl) -amine, 1,3-bis (N-carbazolyl) benzene, (9H-carbazol-9-yl) phenyl) -9H-carbazole), D < Dibenzothiophene, 2-bromodibenzothiophene and the like can be used.

The present invention also provides an organic electroluminescent device including the hole transporting material represented by Formula 1 in a hole transporting layer.

According to the present invention, it is possible to provide a hole transporting material for an organic electroluminescence device having a high glass transition temperature, excellent thermal and morphological stability, and excellent hole transporting properties. Such a hole transporting material has a high temperature and long lifetime It is possible to improve current efficiency, power efficiency and lifetime characteristics as compared with conventional organic electroluminescent devices.

FIG. 1 is a graph showing NMR spectra of a hole transporting material represented by Formula 1a prepared according to an embodiment of the present invention. FIG.
FIG. 2 is a graph showing NMR spectra of a hole transporting material represented by Formula 1b according to an embodiment of the present invention. FIG.
FIG. 3 is a graph showing the NMR spectrum of a hole transport material represented by the formula 1c according to an embodiment of the present invention. FIG.
FIG. 4 is a graph showing the IR spectrum of a hole transport material represented by Formula 1a prepared according to an embodiment of the present invention. FIG.
FIG. 5 is a graph showing the IR spectrum of the hole transporting material of Formula 1b according to an embodiment of the present invention. FIG.
FIG. 6 is a graph showing the IR spectra of the hole transporting material of Formula 1c according to an embodiment of the present invention. FIG.
FIG. 7 is a graph showing a UV-vis absorption spectrum of a hole transporting material represented by Formula 1a prepared according to an embodiment of the present invention. FIG.
8 is a graph showing the UV-vis absorption spectrum of the hole transporting material of Formula 1b prepared according to an embodiment of the present invention.
9 is a graph showing the results of UV-vis absorption spectra of the hole transporting material represented by Formula 1c prepared according to an embodiment 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 hole transport material for an organic electroluminescence device represented by the following general formula (1).

상기 화학식 1의 식에서, [Chemical Formula 1]

In the formula (1)

,

또는

이다.R is

,

or

to be.

delete

delete

The novel hole transporting material for organic electroluminescent devices represented by the above formula (1) has a structure in which a structurally strong and bulky electron transport moiety is bonded to a 4- (9H-carbazol-9-yl) triphenylamine derivative Thereby improving the thermal stability, morphological stability and hole transporting properties. That is, the novel hole transporting material for organic electroluminescent devices represented by Formula 1 of the present invention has a structure in which a bromoaryl derivative is bonded to a carbazole ring of 4- (9H-carbazol-9-yl) triphenylamine derivative .

Specifically, the method for preparing a hole transporting material for an organic electroluminescence device represented by the general formula (1) of the present invention can be illustrated by the following reaction formula (1). The production method of the present invention is not limited to the following Reaction Scheme 1, and it is a matter of course that various organic synthesis methods can be used for the production.

[Reaction Scheme 1]

In the above Reaction Scheme 1, R is as defined in Formula 1 above.

The process for producing a hole transporting material for an organic electroluminescence device represented by the general formula (1) of the present invention can be carried out by reacting 4- (9H-carbazol-9-yl) triphenylamine derivative (4- -yl) triphenylamine derivatives) and bromoaryl derivatives with Suzuki coupling reaction.

Examples of the 4- (9H-carbazol-9-yl) triphenylamine derivatives include 9- (4- (diphenylamino) phenyl) -9H-carbazol- - (diphenylamino) phenyl) may be used -9 H -carbazol-2-yl- 2-boronic acid).

Examples of the bromoaryl derivative include N, N-bis ([1,1'-biphenyl] -4-yl) (4'-biphenyl-4-yl) [1,1'-biphenyl] -4-amine, bis- 4-yl) -amine, 1,3-bis (N-carbazolyl) benzene, 9- (3-benzopyran- (9H-carbazol-9-yl) phenyl) -9H-carbazole), 9-bromo-5- Dibenzothiophene, 2-bromodibenzothiophene and the like can be used.

The 4- (9H-carbazol-9-yl) triphenylamine derivative and the bromoaryl derivative can be subjected to a Suzuki coupling reaction to obtain the compound represented by the formula (1) of the present invention.

It is needless to say that the Suzuki coupling reaction can be carried out according to a conventional method in the art. Specifically, the 4- (9H-carbazol-9-yl) triphenylamine derivative and the bromoaryl derivative are dissolved in an organic solvent, and Pd (PPh ₃ ) ₂ Cl ₃ , K ₂ CO ₃ and Water is added and reacted in an Ar atmosphere at 50 to 70 ° C for 10 to 14 hours, preferably at 60 ° C for 12 hours. Next, the reaction product is extracted with dichloromethane, and the organic layer is separated, dried with MgSO ₄ , filtered and concentrated to obtain a hole transport material for an organic electroluminescence device represented by Formula 1 of the present invention.

The organic solvent used in the Suzuki coupling reaction may be chloroform, toluene, tetrahydrofuran, dioxalic acid, and the like, but is not limited thereto.

The hole transporting material for an organic electroluminescence device represented by Formula 1 of the present invention is a compound represented by the following Formula 1a, 1b or 1c.

[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

The present invention also provides an organic electroluminescent device including the hole transporting material represented by Formula 1 of the present invention as described above as a hole transporting layer. The hole transport material represented by Formula 1 may be used in a hole transport layer of an organic electroluminescent 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 transporting material represented by Formula 1 of the present invention Lt; / RTI > 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 may be a glass, an organic substrate, or a transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness, which is used in a conventional organic electroluminescent device.

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 to form a hole transport layer (HTL). 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.

The reagents and solvents used in the following examples were purchased from Aldrich and TCI Chemicals, Inc., and used without purification.

¹ H and ¹³ C NMR spectra were measured using JEON JNM-ECP FT-NMR spectra operating at 500 MHz and 125 MHz, and infrared spectra were measured using Shimadzu Prestige-21 FT-IR spectra. Samples were measured by KBr pellet method and scanned in the range of 4000-400 cm ^-1 . The UV-vis absorption spectrum was measured using a Scinco S-3100 spectrophotometer, and the photoluminescence (PL) spectra were measured using a CARY Eclipse Varian fluorescence spectrophotometer. The HOMO value was calculated from the oxidation potential and the LUMO value was calculated based on the lowest energy absorption edge of the HOMO value and the UV-vis absorption spectrum. Thermogravimetric analysis (TGA) was also measured using a TG 209F1 (NET-ZSCH) thermal analysis system at a temperature rise rate of 20 ° C min ^-1 .

Example 1. Biphenyl-4-yl- {4 '- [9- (4-diphenylaminophenyl) -9H-carbazol- (Formula 1a) Preparation

To a solution of 9- (4- (diphenylamino) phenyl) -9H-carbazol-2-yl-2-boronic acid (9- (4- (diphenylamino) phenyl) -9H (4'-bromobiphenyl-4-yl) -carbazol-2-yl-2-boronic acid, Compound 1 1.27g (0.28mmol), bromoaryl derivative ) amine (bis-biphenyl-4-yl- (4'-bromobiphenyl-4-yl) -amine) 1.03g (0.1mmol), Pd (OAc) 2 0.02g (0.093mmol) and K ₂ CO 1.03g ( 0.75 mmol) were stirred in an Ar atmosphere at 60 占 폚 for 12 hours. After completion of the reaction, the mixture was extracted with dichloromethane. The organic layer was then separated, dried over magnesium sulfate, filtered and concentrated. The residue was purified by silica gel column chromatography using n-hexane: dichloromethane as an eluent to obtain bis-biphenyl-4-yl- {4 '- [9- (4-diphenylaminophenyl) 9H- carbazol-2-yl] -biphenyl-4-yl} amine (Bis-biphenyl-4-yl- {4 '- [9- (4-diphenylaminophenyl) -9H-carbazol-2-yl] biphenyl-4 -yl} amine, compound (1a) (yield 75%).

FT-IR (KBr pellet): υ _max 3031, 2923, 1625, 1509, 1235, 1015, 1075 cm ^-1 , ¹ H NMR (500 MHz, CDCl ₃ ):? 7.01-8.30 (m, 47H); _{^{13 C NMR (125MHz, CDCl 3}} ): δ147.6, 147.0, 146.9, 141.8, 140.7, 139.4, 139.0, 135.8, 135.2, 131.2, 129.6, 127.1, 126.8, 124.5, 123.6, 122.6, 120.7, 120.4, 120.0, 119.5, 110.0, 108.3; GC-MS: 882.15 for C ₆₆ H ₄₆ N ₃ [M + H ^& lt ^{; +} & gt ^; ].

Example 2. Phenyl) -carbazol-9-yl] -phenyl} -diphenylamine < / RTI > (Formula 1b) Preparation

9- (3-bromo-5- (4-fluorophenyl) -9H-carbamoyl) -9H-carbazole was obtained as a bromoaryl derivative in Example 1, (9-carbazol-9-yl) phenyl) -9H-carbazole was used in place of 4- {2- [ 9-yl-phenyl) -carbazol-9-yl] -phenyl} -diphenylamine ( {4- [2- -phenyl} -diphenylamine, formula 1b) (yield 60%).

FT-IR (KBr pellet): υ _max 3031, 2923, 1625, 1509, 1235, 1015, 1075 cm ^-1 ; ¹ H NMR (500 MHz, CDCl ₃ ):? 7.10-8.35 (m, 40H); _{^{13 C NMR (125MHz, CDCl 3}} ): δ147.5, 146.0, 142.0, 141.8, 140.7, 139.8, 137.5, 124.1, 123.8, 123.7, 123.6, 123.5, 123.2, 122.9, 122.5, 120.7, 120.6, 120.3, 120.2, 120.1, 119.5, 110.2, 110.0, 109.1, 108.7; GC-MS: 817.13 for C ₆₀ H ₄₁ N ₄ [M + H ^& lt ^{; +} & gt ^; ].

Example 3. [4- (2-Dibenzothiophen-2-yl-carbazol-9-yl) -phenyl] -diphenylamine (Formula 1c) Preparation

9- (3-bromo-5- (4-fluorophenyl) -9H-carbamoyl) -9H-carbazole was obtained as a bromoaryl derivative in Example 1, (9H-carbazol-9-yl) phenyl) -9H-carbazole was used in place of [4- (2-dibenzothiophen- sol-9-yl) - phenyl] diphenylamine ([4- (2-Dibenzothiophen- 2-yl-carbazol-9-yl) -phenyl] -diphenylamine, formula 1c) (yield: 72%).

FT-IR (KBr pellet): υ max 3031, 2923, 1625.01, 1509, 1235, 1015, 1075, 1106, 1131㎝ -1, 1 H NMR (500MHz, CDCl 3): δ7.00-8.50 (m, 28H ); _{^{13 C NMR (125MHz, CDCl 3}} ): δ147.6, 147.4, 141.8, 140.1, 139.5, 139.0, 138.4, 136.2, 135.7, 131.2, 129.6, 128.1, 123.8, 123.6, 123.0, 122.4, 121.8, 120.4, 120.1, 119.9, 110.0, 108.7; GC-MS: 593.06 for C ₄₂ H ₂₉ N ₂ S [M + H ^& lt ^{; +} & gt ^; ].

NMR, IR, UV-vis, PL spectroscopies and HOMO-LUMO energy levels were measured using the compounds represented by formulas 1a to 1c prepared in Examples 1 to 3, To 9 and Table 1 below.

division Example 1 The compound of formula 1b The compound of formula 1c T _d (° C) 495 456 387 T _g (° C) 152 152 106 UV? _Max (nm) soln./film 352/350 335/338 312/316 PL? _Max (nm) soln./film 441/432 452/428 426/405 HOMO (eV) ^c 5.69 5.66 558 LUMO (eV) ^c 2.58 2.33 2.08 E _g (eV) 3.11 3.33 3.50

As shown in Table 1, the hole transporting materials of the formulas (1a), (1b) and (1c) prepared in Examples 1 to 3 show peaks at 7-8 ppm indicating many aryl groups in the ¹ H NMR spectrum 1 to 3), IR spectrum the one made according to the present invention when viewed geolro a peak appeared in the vicinity of a characteristic peak of the CC double bond 1,200㎝ ^-1 characteristic peak of 1,600㎝ ^-1 near the CN bond of an aryl group included in the multi- (Figs. 4 to 6). As shown in Figs. 7 to 9, the UV-vis absorption peak was observed at 350 to 310 nm. In addition, the HOMO value of the hole transporting material of Formula 1a, 1b or 1c prepared in Examples 1 to 3 was 5.69 to 5.58 and the LUMO value was 2.58 to 2.08. From the results, It was found that the hole transporting materials of the formulas (1a), (1b) and (1c) of Examples 1 to 3 are suitable for use as a hole transporting layer material of an organic electroluminescent device.

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 (6)

1. A hole transporting material for an organic electroluminescence device,
[Chemical Formula 1]

In the formula (1)
R is

,

or

to be. A process for producing a hole transporting material for an organic electroluminescence device represented by the following Chemical Formula 1, characterized in that a 4- (9H-carbazol-9-yl) triphenylamine derivative and a bromoaryl derivative are subjected to a Suzuki coupling reaction Way:
[Chemical Formula 1]

In the formula (1)
R is

,

or

to be. 3. The method of claim 2,
The 4- (9H-carbazol-9-yl) triphenylamine derivative is obtained by reacting 9- (4- (diphenylamino) phenyl) -9H- carbazol- (diphenylamino) phenyl) method of the hole transporting material for an organic electroluminescent device, characterized in that -9 H -carbazol-2-yl- 2-boronic acid). 3. The method of claim 2,
The bromoaryl derivative can be obtained by reacting N, N-bis ([1,1'-biphenyl] -4-yl) -biphenyl] -4-yl) [1,1'-biphenyl] -4-amine, bis-biphenyl-4-yl- (4'-bromobiphenyl- 4-yl- (4'-bromobiphenyl-4-yl) -amine, 1,3-bis (N-carbazolyl) benzene, (9H-carbazol-9-yl) phenyl) -9H-carbazole), D < Wherein the electron transporting material is one selected from the group consisting of dibenzothiophene and 2-bromodibenzothiophene. An organic electroluminescent device comprising a hole transporting material represented by the following formula (1) in a hole transporting layer:
[Chemical Formula 1]

In the formula (1)
R is

,

or

to be. 6. The method of claim 5,
Wherein the hole transporting material is a compound represented by the following formula (1a), (1b) or (1c):
[Formula 1a]

[Chemical Formula 1b]

[Chemical Formula 1c]

Images