KR20180020577A - Novel compound and organic electroluminescent device comprising the same - Google Patents

Abstract

The present invention provides a compound represented by chemical formula 1, and an organic light-emitting device comprising the same. In the chemical formula 1: Ars are each independently hydrogen, a substituted or unsubstituted aryl group having 6-30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 6-30 carbon atoms, wherein at least one of the two Ars is a phenyl group or a pyridine group; Xs are each independently CR^1 or N, wherein R^1 is hydrogen, halogen, an amino group, a nitrile group, a nitro group, a substituted or unsubstituted alkyl group having 1-30 carbon atoms, a substituted or unsubstituted aryl group having 6-30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 2-30 carbon atoms; and A and B are each independently a substituted or unsubstituted aryl group having 6-30 carbon atoms or a substituted or unsubstituted heteroaryl group having 2-30 carbon atoms.

Description

TECHNICAL FIELD [0001] The present invention relates to a novel compound and an organic light emitting device comprising the compound.

The present invention relates to a novel compound and an organic light emitting device comprising the same.

In recent years, an organic light emitting device capable of being driven by a low voltage in a self-luminous mode has a better viewing angle and contrast ratio than a liquid crystal display (LCD), which is a mainstream of a flat panel display device, It has been attracting attention as a next generation display device because it is advantageous in terms of power consumption and has a wide color reproduction range.

Materials used as an organic material layer in an organic light emitting diode can be largely classified into a light emitting layer material, a hole injecting layer material, a hole transporting layer material, an electron transporting layer material, and an electron injection layer material according to functions. The light emitting material may be classified into a polymer and a single molecule according to molecular weight, and may be classified into a fluorescent material derived from singlet excited state of electrons according to a light emitting mechanism, a phosphorescent material derived from a triplet excited state of electrons, Emitting materials derived from the movement of electrons to the singlet excitation state, and the light-emitting material is classified into blue, green, and red light-emitting materials and yellow and orange light-emitting materials necessary for realizing better color according to the luminescent color . Further, in order to increase the color purity and to increase the luminous efficiency through energy transfer, a host / dopant system can be used as a luminescent material. The principle is that when the energy band gap is smaller than that of the host and a small amount of dopant is mixed into the light emitting layer, the excitons generated by the host are transferred to the dopant to emit light. Using this principle, light of a desired wavelength can be obtained depending on the type of the dopant and the host.

Various compounds have been known as materials used in such organic light emitting devices. However, organic light emitting devices using known materials have been difficult to put to practical use due to high driving voltage, low efficiency, and short lifetime. Accordingly, efforts have been made to develop an organic light emitting device having low voltage driving, high luminance, and long life using a material having excellent characteristics.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a novel compound having excellent thermal properties and thin film stability and long life span during device fabrication.

It is also an object of the present invention to provide a light emitting layer material capable of designing not only blue, green and red but also a dark blue material.

It is another object of the present invention to provide a novel compound capable of stabilizing cations formed in the device and achieving low voltage and high efficiency.

As means for achieving the above object,

The present invention provides a compound represented by the following general formula (1).

≪ Formula 1 >

(In the formula 1,

Ar is independently hydrogen, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, or a substituted or unsubstituted C ₆ -C ₃₀ heteroaryl group, at least one of which is a phenyl group or a pyridine group,

X is independently CR ¹ or N, wherein R ¹ is a hydrogen, a halogen, an amino group, a nitrile group, a nitro group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₆ -C _A substituted or unsubstituted C ₂ -C ₃₀ aryl group or a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group,

A, B each independently represent a substituted or non-C ₆ ~ C ₃₀ aryl group, or an optionally substituted unsubstituted C ₂ to C ₃₀ heteroaryl group)

At least one or more of A and B in the above formula (1) may be represented by the following formula (2), and specifically may be represented by the formula (3).

(2)

(3)

The formula (1) may be represented by the following formula (4).

≪ Formula 4 >

In addition, an embodiment of the present invention provides an organic light emitting device including the above compound between an anode and a cathode, specifically, it may be included in a light emitting layer.

The compound according to the present invention has an acridine structure, prevents the decrease of optical energy (singlet and triplet energy) due to the effect of steric hindrance, improves the rigidity of the molecule and improves the thermal property, Do. The acridine structure stabilizes the cations formed in the device to realize low voltage and high efficiency. The acridine structure prevents the increase of the conjugation length and maintains high triplet energy, so that not only blue, green, It is possible to apply it to excellent.

1 is a schematic cross-sectional view of a configuration of an organic light emitting diode according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The compound according to the present invention is represented by the following general formula (1).

≪ Formula 1 >

Wherein Ar is independently hydrogen, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, or a substituted or unsubstituted C ₆ -C ₃₀ heteroaryl group, at least one of which is a phenyl group or a pyridine group,

X is each independently selected from CR1 or N, wherein R1 is a hydrogen, a halogen, an amino group, a nitrile group, a nitro group, or a substituted or unsubstituted C ₁ ~ C ₃₀ alkyl group, a substituted or unsubstituted C ₆ ~ C ₃₀ of An aryl group or a substituted or unsubstituted C ₂ to C ₃₀ heteroaryl group,

A, B are each a substituted or unsubstituted C ₆ ~ C ₃₀ aryl group or independently a substituted or unsubstituted C ₂ ~ C ₃₀ heteroaryl group.

Specific examples of the substituent in the above substitution include a halogen, an amino group, a nitrile group, a nitro group, a C ₁ to C ₂₀ alkyl group, and a C ₁ to C ₂₀ alkoxy group.

When Ar is pyridine or X is N, acridine increases the amount of excitons formed by the combination of electrons and holes by increasing the amount of electrons and holes in the luminescent layer, Thereby increasing the efficiency.

More specifically, at least one or more of A and B may be represented by the following formula (2).

(2)

Wherein each X is independently C, CR ¹ R ² , N, or NR ¹ and at least one is N, wherein R ¹ and R ² are independently hydrogen, a halogen, an amino group, a nitrile group, A substituted or unsubstituted C ₁ to C ₃₀ alkyl group, a substituted or unsubstituted C ₆ to C ₃₀ aryl group or a substituted or unsubstituted C ₂ to C ₃₀ heteroaryl group,

Cy is any one of a five-membered ring and a six-membered ring.

More specifically, the formula (2) may be any one of the compounds represented by the following formula (3).

(3)

Specifically, when A or B has a carbazole structure, it is preferable that B does not have the same structure as A. That is, when both A and B were carbazole, the driving voltage was high and the device characteristics were not good. The device characteristics refer to, for example, current efficiency, power efficiency, quantum efficiency, and the like.

In one embodiment, Formula 1 may be a compound represented by Formula 4 below.

≪ Formula 4 >

In Formula 4, Ar, X, and A are the same as defined in Formula 1 above.

The compound according to one embodiment of the present invention can realize a low voltage and high efficiency by stabilizing a cation formed in the device by a cyclic compound structure and has an acridine structure and an A structure (more specifically, a structure of the formula 3) Is bonded to the meta position of the biphenyl to provide an effect of steric hindrance, and optical characteristics are improved, so that the device characteristics are excellent. As a result, the introduction of an acridine structure prevents the decrease of optical energy (singlet and triplet energy) and maintains a high triplet energy, so that it can be applied to blue light, green light, red light, .

The following compounds are specific examples of the compounds according to the present invention. The following examples are only illustrative of the present invention, and the present invention is not limited thereto.

Hereinafter, an organic light emitting device according to the present invention will be described.

The present invention provides an organic electroluminescent device comprising the compound represented by the above formula (1). Specifically, the compound represented by Formula 1 is included in an organic light emitting device as a light emitting layer material.

The organic light emitting device includes a hole injection layer (HIL) 11, a hole transport layer (HTL) 12, an emission layer (EML) 13, and an electron transport layer (ETL) 14 between an anode 10 and a cathode ), And an electron injection layer (EIL, 15). Alternatively, a hole blocking layer (HBL) (not shown) may be formed between the light emitting layer (EML) 13 and the electron transporting layer (ETL) 14 and between the hole transporting layer (HTL) Layer (EBL, not shown) may be further included.

First, an anode electrode material having a high work function is deposited on the substrate to form an anode. At this time, the substrate can be a substrate used in conventional organic light emitting devices, and it is particularly preferable to use a glass substrate or a transparent plastic substrate having excellent mechanical strength, thermal stability, transparency, surface smoothness, ease of handling, and waterproofness. As the material for the anode electrode, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2), zinc oxide (ZnO) and the like which are transparent and excellent in conductivity can be used. The anode electrode material can be deposited by a conventional anode formation method, and specifically, it can be deposited by a deposition method or a sputtering method.

Next, a hole injection layer material may be formed on the anode electrode by a method such as a vacuum deposition method, a spin coating method, a casting method, or an LB (Langmuir-Blodgett) method, but it is easy to obtain a uniform film quality, It is preferable to form it by a vacuum evaporation method. When the hole injection layer is formed by the vacuum deposition method, the deposition conditions vary depending on the compound used as the material of the hole injection layer, the structure and thermal properties of the desired hole injection layer, and the like. In general, the deposition temperature is 50-500 [ A vacuum degree of 10 ^-5 to 10 ^-3 torr, a deposition rate of 0.01 to 100 Å / sec, and a layer thickness range of 10 Å to 5 탆.

The hole injection layer material is not particularly limited and may be a phthalocyanine compound such as copper phthalocyanine disclosed in U.S. Patent No. 4,356,429 or a star burst type amine derivative TCTA (4,4 ', 4 "-tri (N-carbazolyl) (4,4 ', 4 "-tris (3-methylphenylamino) triphenylamine), m-MTDAPB ), HI-406 (N1, N1'- (biphenyl-4,4'-diyl) bis (N1- (naphthalen- 1 -yl) -N4, N4-diphenylbenzene- It can be used as a hole injection layer material.

Next, a hole transporting layer material may be formed on the hole injecting layer by a method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, etc. However, since a uniform film quality can be easily obtained, It is preferably formed by a vapor deposition method. When the hole transporting layer is formed by the vacuum deposition method, the deposition conditions vary depending on the compound used, but it is generally preferable to select the conditions within the substantially same range as the formation of the hole injection layer. The hole transport layer material may be selected from among conventionally known materials used in the hole transport layer. Specifically, carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, N, N'-bis (3- (Methylphenyl) -N, N'-diphenyl- [1,1-biphenyl] -4,4'-diamine (TPD), N.N'-di (naphthalen- And general amine derivatives having an aromatic condensed ring such as phenylbenzidine (? -NPD).

Thereafter, the light emitting layer material may be formed on the hole transporting layer by a method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, etc. However, from the viewpoint of obtaining a uniform film quality and difficulty in producing pin holes, As shown in Fig. When the light emitting layer is formed by the vacuum vapor deposition method, the deposition conditions vary depending on the compound used, but it is generally preferable to select the conditions within the same range as the formation of the hole injection layer. The light emitting layer material may be a novel compound according to an embodiment of the present invention, or a known host may be used together. In addition, dopants can be used together. The dopant is not limited, but a phosphorescent or fluorescent dopant can be used together to form a light emitting layer. For example, BD142 (N6, N12-bis (3,4-dimethylphenyl) (2-phenylpyridine) iridium) as a phosphorescent dopant, Ir (ppy) 3 (tris (2-phenylpyridine) iridium) as a phosphorescent dopant, and a blue phosphorescent dopant such as F2Irpic (Iridium (III) bis [4,6-difluorophenyl) -pyridinate-N, C2 '] picolinate) and UDC's red phosphorescent dopant RD61 may be co-vacuum deposited (doped). The doping concentration of the dopant is not particularly limited, but is preferably doped with 0.01 to 15 parts by weight of the dopant relative to 100 parts by weight of the host. If the content of the dopant is less than 0.01 part by weight, the amount of the dopant is not sufficient and color development is not properly performed. If the amount is more than 15 parts by weight, the efficiency is drastically reduced due to the concentration quenching phenomenon.

When the phosphorescent dopant is used together with the phosphorescent dopant, it is preferable to further laminate the hole blocking layer material (HBL) by a vacuum evaporation method or a spin coating method in order to prevent the triplet exciton or hole from diffusing into the electron transporting layer . As the hole blocking layer material that can be used at this time, conventionally known materials may be used alone or in combination. Examples of known materials include oxadiazole derivatives and triazole derivatives, phenanthroline derivatives, and hole blocking layer materials described in Japanese Patent Laid-Open Publication No. 11-329734 (A1). Representative examples include Balq (bis Phenanthrolines based compounds (e.g., UDC company BCP (Bassocouroin)), and the like can be used.

An electron transport layer is formed on the light emitting layer formed as described above. The electron transport layer is formed by a vacuum deposition method, a spin coating method, a casting method, or the like, and is preferably formed by a vacuum deposition method. The electron transport layer material may be selected from commonly known materials and used arbitrarily. For example, a quinoline derivative, especially tris (8-quinolinolato) aluminum (Alq3), or ET4 (6,6 '- (3,4-demimethy1-1,1-dimethyl- , 5-diyl) di-2,2'-bipyridine) can be used.

An electron injection layer may be stacked on the electron transport layer as a material having a function of facilitating the injection of electrons from the cathode. The electron injection layer material may be LiF, NaCl, CsF, Li2O, BaO, or the like.

The electron injection layer is formed by a conventional vacuum deposition method, a spin coating method, a casting method, or the like, and is preferably formed by a vacuum deposition method.

Finally, a metal for forming a cathode is formed on the electron injection layer by a vacuum evaporation method, a sputtering method, or the like, and used as a cathode. As the metal for cathode formation, a metal, an alloy, an electrically conductive compound having a low work function, and a mixture thereof can be used. Specific examples thereof include Li, Mg, Al, Al-Li, Ca, Mg-In, Mg-Ag, . Also, a transmissive cathode using ITO or IZO may be used to obtain a front light emitting element.

The organic light emitting device of the present invention can have an organic light emitting device having various structures as well as an anode, a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, an electron injecting layer and a cathode structure, Layer or an intermediate layer of two layers may be further formed.

As described above, the thickness of each organic material layer formed according to the present invention can be controlled according to the required degree, and is preferably 10 to 1,000 nm, more preferably 20 to 150 nm.

In addition, since the organic material layer containing the compound represented by the formula (1) can control the thickness of the organic material layer in the molecular unit, the present invention has advantages of uniform surface and excellent shape stability.

Hereinafter, the present invention will be described in more detail with reference to synthesis examples of compounds according to one embodiment of the present invention and production examples of organic light emitting devices. The following examples illustrate the invention and are not intended to limit the scope of the invention.

The reactants used in the synthesis examples of the compound according to one embodiment of the present invention are as follows.

The reactants (1)

Reactants (2)

The reactants (3)

Reactants (4)

The reactants (5)

Reactants (6)

Reactants (7)

< Manufacturing example 1> Compound 10  of  synthesis

10 g of reactant (1), 12 g of reactant (2) and 0.9 g of tetrakis (triphenylphosphine) palladium (0) were dissolved in 50 ml of dioxane and 11.2 g of sodium carbonate was added to a 250 ml flask under argon or nitrogen atmosphere Dissolved in 20 ml of water was added thereto, and the mixture was heated and stirred for 24 hours.

After the reaction, the reaction mixture was cooled to room temperature and the precipitated crystals were separated by filtration. This was recrystallized from toluene to synthesize 6.5 g (40%) of Compound 10 .

(1H, m), 7.69 (1H, d), 7.89 (6H, s), 6.90 (1H, s), 8.00 (1H, s), 8.15 (2H, d)

LC-MS Purity &lt; / RTI &gt; 99.91%, Rt = 2.67 min; MS Calcd. 602.76; MS Found: 602 [M].

< Manufacturing example 2> Compound 60 Synthesis of

Compound 60 was synthesized by using reactant (3) in place of reactant (2) in the same manner as in Production Example 1.

MS Calcd .: 603.27; MS Found: 603.4 [M].

< Manufacturing example 3> Compound One Synthesis of

Compound 1 was synthesized by using reactant (4) instead of reactant (1) and reactant (5) instead of reactant (2) in the same manner as in Production Example 1.

MS Calcd. 602.76; MS Found: 602 [M].

< Manufacturing example 4> Compound 59 Synthesis of

Compound 59 was synthesized by using reactant (6) instead of reactant (1) and reactant (5) instead of reactant (2) in the same manner as in Production Example 1.

MS Calcd .: 603.27; MS Found: 603.4 [M].

< Manufacturing example 5> Compound 14 Synthesis of

Compound 14 was synthesized by using reactant (4) instead of reactant (1) in the same manner as in Production Example 1.

MS Calcd .: 678.87; MS Found: 678 [M].

< Manufacturing example 6> Compound 7 Synthesis of

Compound 7 was synthesized by using reactant (6) instead of reactant (1) in the same manner as in Production Example 1.

MS Calcd .: 680.31; MS Found: 679 [M].

< Manufacturing example 7> Compound 58 Synthesis of

Compound 58 was synthesized by using reactant (4) instead of reactant (1) and reactant (3) instead of reactant (2) in the same manner as in Production Example 1.

MS Calcd .: 680.31; MS Found: 679 [M].

< Manufacturing example 8> Compound  Synthesis of 26

Compound 26 was synthesized by using reactant (7) instead of reactant (1) in the same manner as in Production Example 1.

MS Calcd .: 644.32; MS Found: 644 [M].

Manufacture of organic light emitting device

An organic light emitting device was prepared according to the structure shown in FIG. The organic light emitting device includes an anode 10, a hole injecting layer 11, a hole transporting layer 12, an electron blocking layer (not shown), a light emitting layer 13, a hole blocking layer (not shown), and an electron transporting layer 14 / electron injecting layer 15 / cathode 16 in that order.

(Example) or CBP (Comparative Example) was used as the hole injection layer 11 and NPB as the hole transport layer 12 and 13 (Comparative Example) as the light emitting layer 13, Ir (ppy) 3, BCP as the hole blocking layer, ET01 and Liq as the electron transport layer (14), and Liq as the electron injection layer (15).

Example  One

A glass substrate coated with thin indium tin oxide (ITO) was washed with distilled water ultrasonic waves. After the distilled water was washed, the substrate was ultrasonically cleaned with a solvent such as isopropyl alcohol, acetone, or methanol, and the substrate was dried and transferred to a plasma cleaner. Then, the substrate was cleaned using oxygen plasma for 5 minutes, , 4,4 ', 4 "-tris (N, N- (2-naphthyl) -phenylamino) triphenylamine (2-TNATA) was added to the cell in the vacuum evaporation apparatus and the degree of vacuum in the chamber reached 10-7 torr , 2-TNATA was evaporated by applying current to the cell to deposit a 60 nm thick hole injection layer 11 on the ITO substrate.

Next, N, N'-bis (α-naphthyl) -N, N'-diphenyl-4,4'-diamine (NPB) was added to another cell in the vacuum evaporation apparatus and NPB was evaporated by applying current to the cell A hole transport layer 12 having a thickness of 20 nm was deposited on the hole injection layer.

(2-phenylpyridine) iridium (Ir (ppy) 3) was added to one cell in the vacuum vapor deposition apparatus as a host material and the compound prepared in Preparation Example 1 in the other cell, Evaporated at a different rate and doped to 5 to 15 mol% to deposit a 35 nm thick light emitting layer 13 on the hole transport layer.

Then, 2,9-dimethyl-4,7-diphenyl- and 1,10-phenathroline (BCP) were deposited to a thickness of 5 nm as a hole blocking layer (not shown) 1 &lt; / RTI &gt;

Liq was deposited to a thickness of 1.5 nm as the electron injection layer 15, an Al cathode 16 was deposited to a thickness of 100 nm, and then sealed in a glove box to prepare an organic light emitting device.

Example  2 to Example  8

An organic light emitting device was fabricated in the same manner as in Example 1, except that the compound prepared in Preparative Examples 2 to 8 was used instead of the compound prepared in Preparative Example 1, respectively.

Comparative Example  One

A device was fabricated in the same manner as in Example 1 except that CBP was used in place of the light emitting layer compound of Production Example 1.

Comparative Example  2

A device was fabricated in the same manner as in Example 1 except that mPCBP was used in place of the light emitting layer compound of Production Example 1.

Comparative Example  3

The device was fabricated in the same manner as in Example 1 except that mdPCBP was used in place of the light emitting layer compound of Production Example 1.

Comparative Example  4

The device was fabricated in the same manner as in Example 1 except that pAr was used in place of the light emitting layer compound of Production Example 1.

Evaluation of performance of organic light emitting device

A voltage was applied to the Keithley 2400 source measurement unit to inject electrons and holes and the luminance was measured using a Konica Minolta spectroscope (CS-2000). The performance of the organic light emitting devices of the examples and the comparative examples was evaluated by measuring the current efficiency and lifetime with respect to the applied voltage under an atmospheric pressure condition of 3,000 cd / m ² , and the results are shown in Table 1.

Classification Host Op. V Cd / A LT90 Example 1 Production Example 1 4.3 57 355 Example 2 Production Example 2 4.1 51 338 Example 3 Production Example 3 4.4 55 331 Example 4 Production Example 4 4.0 51 351 Example 5 Production Example 5 4.4 52 311 Example 6 Production Example 6 4.0 55 313 Example 7 Production Example 7 4.1 55 310 Example 8 Production Example 8 4.0 55 330 Comparative Example 1 CBP 5.5 48 150 Comparative Example 2 mPCBP 5.5 43 60 Comparative Example 3 mdPCBP 5.6 41 31 Comparative Example 4 pAr 4.3 51 56

As shown in Table 1, it can be seen that the materials of Examples of the present invention have remarkably excellent luminescence properties and lifetime in comparison with Comparative Examples. In particular, the device exhibited better current characteristics than the device of Comparative Example 3, exhibiting a driving characteristic lower than 1 V, and improved lifetime, thereby realizing a low voltage, high efficiency and long life material.

10: anode
11: Hole injection layer (HIL)
12: hole transport layer (HTL)
13: Light emitting layer (EML)
14: electron transport layer (ETL)
15: electron injection layer (EIL)
16: cathode

Claims (8)

A compound represented by the following formula (1).

&Lt; Formula 1 >

(In the formula 1,
Ar is independently hydrogen, a substituted or unsubstituted C ₆ -C ₃₀ aryl group, or a substituted or unsubstituted C ₆ -C ₃₀ heteroaryl group, at least one of which is a phenyl group or a pyridine group,
X is independently CR ¹ or N, wherein R ¹ is a hydrogen, a halogen, an amino group, a nitrile group, a nitro group, a substituted or unsubstituted C ₁ -C ₃₀ alkyl group, a substituted or unsubstituted C ₆ -C _A substituted or unsubstituted C ₂ -C ₃₀ aryl group or a substituted or unsubstituted C ₂ -C ₃₀ heteroaryl group,
A, B each independently represent a substituted or non-C ₆ ~ C ₃₀ aryl group, or an optionally substituted unsubstituted C ₂ to C ₃₀ heteroaryl group)
The method according to claim 1,
Wherein at least one of A and B in the formula (1) is represented by the following formula (2).

(2)

(In the formula (2)
X is independently at each occurrence C, CR ¹ R ² , N, or NR ¹ and at least one is N, wherein R ¹ and R ² are independently hydrogen, halogen, an amino group, a nitrile group, A substituted or unsubstituted C ₁ to C ₃₀ alkyl group, a substituted or unsubstituted C ₆ to C ₃₀ aryl group or a substituted or unsubstituted C ₂ to C ₃₀ heteroaryl group,
Cy is any one of five-membered rings and six-membered rings)
3. The method of claim 2,
(2) is one of the compounds represented by the following formula (3).

(3)

3. The method of claim 2,
When A or B has a structure of carbazole, B has a structure different from A;
The method according to claim 1,
Wherein the compound represented by Formula 1 is represented by Formula 4 below.

&Lt; Formula 4 >

(Wherein Ar, X, and A are the same as defined in Formula 1)
The method according to claim 1,
Wherein the compound of formula (1) is one of the compounds represented by the formula:

An organic light emitting device comprising a compound of any one of claims 1 to 6 between an anode and a cathode.
8. The method of claim 7,
Wherein the compound is included in at least one of the light emitting layers.

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