KR101695063B1 - Organic light emitting device and method for preparing the same - Google Patents

Abstract

The present invention relates to an organic light emitting device comprising an anode, a cathode, and at least one organic layer disposed between the anode and the cathode, wherein at least one of the organic layers includes a host material and an n-type dopant, Wherein the n-type dopant is at least one compound selected from the group consisting of an alkali metal, an alkaline earth metal, and a rare earth metal, at least one of which is a chemical bond between atoms having a difference in electronegativity between atoms constituting the compound, And at least one organic compound selected from the group consisting of an organic compound and an organic compound.

Description

TECHNICAL FIELD [0001] The present invention relates to an organic light emitting diode (OLED) and a method of manufacturing the same,

The present application claims the benefit of Korean Patent Application No. 10-2013-0116488, filed on September 30, 2013, to the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference.

The present invention relates to an organic light emitting device and a method of manufacturing the same.

The organic light emission phenomenon is one example in which current is converted into visible light by an internal process of a specific organic molecule. The principle of organic luminescence phenomenon is as follows. When an organic layer is positioned between an anode and a cathode, when a voltage is applied between the two electrodes, electrons and holes are injected into the organic layer from the cathode and the anode, respectively. Electrons and holes injected into the organic material layer recombine to form an exciton, and the exciton falls back to the ground state to emit light. An organic light emitting device using such a principle may be generally composed of an organic material layer including a cathode, an anode, and an organic material layer disposed therebetween, for example, a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer.

As a material used in an organic light emitting device, a pure organic material or a complex in which an organic material and a metal form a complex is mostly used. Depending on the application, a hole injecting material, a hole transporting material, a light emitting material, an electron transporting material, . As the hole injecting material and the hole transporting material, an organic material having a p-type property, that is, an organic material that is easily oxidized and electrochemically stable at the time of oxidation is mainly used. On the other hand, as an electron injecting material or an electron transporting material, an organic material having an n-type property, that is, an organic material that is easily reduced and electrochemically stable when being reduced is mainly used. As the light emitting layer material, a material having both a p-type property and an n-type property, that is, a material having both a stable form in oxidation and in a reduced state is preferable, and a material having a high luminous efficiency for converting an exciton into light desirable.

In addition to the above, it is preferable that the material used in the organic light emitting device further has the following properties.

First, the material used in the organic light emitting device is preferably excellent in thermal stability. This is because joule heating occurs due to the movement of charges in the organic light emitting device. At present, NPB, which is mainly used as a hole transporting layer material, has a glass transition temperature of 100 DEG C or less, which makes it difficult to use in an organic light emitting device requiring a high current.

Secondly, in order to obtain a highly efficient organic light emitting device capable of driving at a low voltage, holes or electrons injected into the organic light emitting element should be smoothly transferred to the light emitting layer, and injected holes and electrons should not escape from the light emitting layer. For this purpose, the material used in the organic light emitting device should have an appropriate band gap and a HOMO or LUMO energy level. At present, in the case of PEDOT: PSS used as a hole transport material in an organic light emitting device manufactured by a solution coating method, since the LUMO energy level is lower than the LUMO energy level of an organic material used as a light emitting layer material, There is a difficulty in.

In addition, materials used in organic light emitting devices should have excellent chemical stability, charge mobility, and interface characteristics with electrodes or adjacent layers. That is, the material used in the organic light emitting device should have little deformation of the material due to moisture or oxygen. In addition, by having appropriate hole or electron mobility, it is necessary to maximize the formation of excitons by balancing the density of holes and electrons in the light emitting layer of the organic light emitting device. And, for the stability of the device, the interface with the electrode including the metal or the metal oxide should be good.

Accordingly, there is a need in the art to develop organic materials having the above-mentioned requirements.

Korean Patent Publication No. 10-2011-0027635

Accordingly, the present inventors have found that a compound capable of satisfying the conditions required for a material usable in an organic light emitting device, for example, an appropriate energy level, electrochemical stability, and thermal stability, And a method for increasing the lifetime of the organic light emitting device.

In one embodiment of the present application,

An organic light emitting device comprising a cathode, a cathode, and at least one organic layer disposed between the anode and the cathode,

At least one of the organic material layers includes a host material and an n-type dopant,

Wherein at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound is 0.5 or more in the compound constituting the host material,

The n-type dopant includes at least one selected from the group consisting of an alkali metal, an alkaline earth metal, and a rare earth metal.

Further, another embodiment of the present application,

Sequentially forming an anode, an organic layer and a cathode on a substrate,

Wherein at least one layer of the organic material layer includes a host material and an n-type dopant,

Wherein at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound is 0.5 or more in the compound constituting the host material,

The n-type dopant includes at least one selected from the group consisting of an alkali metal, an alkaline earth metal, and a rare earth metal.

The organic light emitting device according to the present application includes a cathode, a cathode, and one or more organic layers disposed between the anode and the cathode, and by changing a dipole moment of the compound contained in the organic layer, Life characteristics can be greatly improved and the stability of the organic light emitting device can be improved.

1 is an example of an organic light emitting device structure in which an anode 102, a light emitting layer 105, and a cathode 107 are sequentially stacked on a substrate 101.
2 is an example of an organic light emitting device structure in which an anode 102, a hole injection / hole transporting and light emitting layer 105, an electron transporting layer 106, and a cathode 107 are sequentially laminated on a substrate 101.
3 is an example of an organic light emitting device structure in which a substrate 101, an anode 102, a hole injecting layer 103, a hole transporting and emitting layer 105, an electron transporting layer 106, and a cathode 107 are sequentially stacked .
4 is an example of an organic light emitting device structure in which a substrate 101, an anode 102, a hole injecting layer 103, a hole transporting layer 104, an electron transporting and emitting layer 105, and a cathode 107 are sequentially stacked .
5 is a graph showing lifetime characteristics of the organic luminescent device of Example 1 and Comparative Example 1 according to one embodiment of the present application.
6 is a graph showing voltage characteristics of the organic light emitting device of Example 1 and Comparative Example 1 according to one embodiment of the present application.

The present application will be described in more detail below.

According to an embodiment of the present invention, an organic light emitting device includes a cathode, a cathode, and at least one organic layer disposed between the anode and the cathode, wherein at least one of the organic layers includes a host material and an n-type dopant And at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound of at least 0.5 in the compound constituting the host material, wherein the n-type dopant is at least one selected from the group consisting of an alkali metal, Rare earth metals, and rare earth metals.

In the present application, a compound containing a chemical bond between atoms having an electronegativity difference of more than 0.5 between atoms is -O-Li, -N-Li, -C = O, -CO-, -CF, - NF, -Si = O, -Si-O-, -Si-F, -Si-Cl, -Si-Br, -P = O, -PO-, -PF, -P- , And the like, but is not limited thereto.

In the present application, the electronegativity may be a Pauling scale electronegativity as a reference. The above-mentioned electronegatron is a variable that interprets the phenomenon of making the bond more stable by making the chemical bond between the atoms be polarized. When the atoms are bonded to each other, electrons having a higher electronegativity are pulled more than electrons and relatively negative charges are drawn. This causes a dipole moment to be generated, and an electric field in which the dipole moment is divergent, Type dopants existing in such a state that they can be influenced by the diffusion of the n-type dopants can be prevented from diffusing, thereby contributing to the stability of the device.

In the present application, the n-type dopant includes at least one selected from the group consisting of an alkali metal, an alkaline earth metal, and a rare earth metal. More specifically, the n-type dopant may include at least one selected from the group consisting of Mg, Ca, Li, Na, K, and Cs, but is not limited thereto.

In the present application, the compound constituting the host material includes at least one bond between atoms having an electronegativity difference of not less than 0.5. Electrons with higher electronegativity attract more electrons than relative atoms and have a relatively negative charge, which results in the dipole moment of the two atoms. The n-type dopants around the host existing in a state in which the electric field can be influenced by the electric field in which the dipole moment is diverging can be influenced by an electric field, similarly to the ion state. Similarly, -Type dopants, thereby contributing to the stability of the device and contributing to an improvement in the lifetime of the device.

In the present application, the organic material layer may include a light emitting layer, and an organic material layer including the host material and the n-type dopant may be disposed between the cathode and the light emitting layer.

In particular, an electron transporting layer may be included between the cathode and the light emitting layer, and the electron transporting layer may include the host material and the n-type dopant.

According to the present invention, an electron transport layer for transporting electrons from a cathode to an emission layer of an organic light emitting device is doped with an n-type dopant in order to enhance charge efficiency and conductivity of the electrode and increase the energy efficiency of the organic light emitting device . Examples of the n-type dopant include, but are not limited to, alkali metals, alkaline earth metals, and rare earth metals.

Particularly, the alkali metal tends to diffuse in the electron transporting layer, and when the alkali metal gradually reaches the light emitting layer, the alkali metal acts as a metal ion quenching, As shown in FIG. In order to solve this problem, in the present application, a compound capable of preventing the diffusion of an alkali metal in the ion state into the light emitting layer is applied as a host material, thereby contributing to realization of a stable organic light emitting device.

In the present application, the host material may include a compound represented by the following formula (1).

[Chemical Formula 1]

In Formula 1,

X ₁ is N or CR 3, X ₂ is N or CR ₄ , X ₃ is N or CR ₅ , X ₄ is N or CR ₆ , Y ₁ is N or CR 7, Y ₂ is N or CR 8, Y ₃ is N or CR9, Y ₄ is N or CR10, and, X ₁ to X ₄ and Y ₁ to Y ₄ are N at the same time is, R3 to R10 are each independently not - (L) p- (Y) q to or Wherein at least one of R3 to R10 is represented by the following general formula (1A), wherein p is an integer of 0 to 10, q is an integer of 1 to 10, and two or more adjacent groups of R3 to R10 are A cyclic or polycyclic ring can be formed,

≪ EMI ID =

L is oxygen; sulfur; Substituted or unsubstituted nitrogen; Substituted or unsubstituted phosphorus; A substituted or unsubstituted arylene group; A substituted or unsubstituted alkenylene group; A substituted or unsubstituted fluorenylene group; A substituted or unsubstituted carbazolylene group; Or a substituted or unsubstituted heteroarylene group containing at least one of N, O and S atoms,

Y is hydrogen; heavy hydrogen; A halogen group; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkylthio group; A substituted or unsubstituted arylthio group; A substituted or unsubstituted alkylsulfoxy group; A substituted or unsubstituted arylsulfoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted alkylamine group; A substituted or unsubstituted aralkylamine group; A substituted or unsubstituted arylamine group; A substituted or unsubstituted heteroarylamine group; A substituted or unsubstituted aryl group; A substituted or unsubstituted fluorenyl group; A substituted or unsubstituted carbazole group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms;

R 1 and R 2 may be connected to form a substituted or unsubstituted aliphatic, aromatic or heteroaromatic monocyclic or polycyclic ring, and when R 1 and R 2 do not form a ring, R 1 and R 2 may be the same Independently of one another, hydrogen, a substituted or unsubstituted C ₃ -C ₄₀ cycloalkyl group; An aryl group, a substituted or unsubstituted C ₆ ~C _60; A substituted or unsubstituted C ₂ ~C ₄₀ alkenyl group; A substituted or unsubstituted heterocyclic group of C ₂ ~C _60,

The aromatic or heteroaromatic monocyclic and polycyclic rings formed by connecting R 1, R 2, and R 1 and R 2 are each independently substituted with - (L) p - (Y) q,

When two or more L and Y are present, they are each independently the same or different,

A is each independently O, S or Se,

Ar ₁ and Ar ₂ are each independently a substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms;

Ar ₃ is independently a substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group containing at least one of N, O and S atoms.

In the above formula (1), when R1 and R2 are connected to form one ring, they may be represented by the following formula (2).

(2)

In Formula 2,

X ₁ to X ₄ , and Y ₁ to Y ₄ are as defined in Formula 1,

(N) In n ₁ , N represents a nitrogen atom, which indicates that the nitrogen atom can substitute for the carbon atom in the benzene ring,

(N) n ₁ , n ₁ is an integer of 0 to 6,

R < ₁₁ > is the same as defined for R < 3 > to R <

k ₁ is an integer of 0 to 4;

In the above formula (1), when R1 and R2 are connected to form a ring of two or more polycyclic rings, the ring may be represented by the following formula (3) or (4).

(3)

[Chemical Formula 4]

In the above formulas (3) and (4)

X ₁ to X ₄ , and Y ₁ to Y ₄ are as defined in Formula 1,

(N) In n ₁ and (N) n ₂ , N represents a nitrogen atom, which indicates that the nitrogen atom can replace the carbon atom in the benzene ring,

(N) from n ₁ n1 is an integer from 0 to 2,

(N) in n ₂ n2 is an integer from 0 to 2,

R ₁₁ and R ₁₂ are each independently the same as defined for R 3 to R 10 in the above formula (1)

k ₁ is an integer of 0 to 4, and k ₂ is an integer of 0 to 4;

In the above formula (1), when R 1 and R 2 do not form a ring, R ₁ and R ₂ are each a substituted or unsubstituted phenyl group substituted with R ₁₁ and R ₁₂ , or a substituted or unsubstituted nitrogen (N) Aromatic ring group. For example, the formula (1) may be represented by the following formula (5).

[Chemical Formula 5]

In Formula 5,

X ₁ to X ₄ , and Y ₁ to Y ₄ are as defined in Formula 1,

(N) In n ₁ and (N) n ₂ , N represents a nitrogen atom, which indicates that the nitrogen atom can replace the carbon atom in the benzene ring,

(N) from n ₁ n1 is an integer from 0 to 2,

(N) in n ₂ n2 is an integer from 0 to 2,

R ₁₁ and R ₁₂ are each independently the same as defined for R 3 to R 10 defined in the above formula (1)

k ₁ is an integer of 0 to 4, and k ₂ is an integer of 0 to 4;

In the present application, the formula (1) may be represented by the following formula (6), but is not limited thereto.

[Chemical Formula 6]

In Formula 6,

Ar ₁ to Ar ₃ , and A are the same as defined in Formula 1,

m ₁ is an integer of 0 to 4, and m ₂ is an integer of 0 to 4, except that m ₁ and m ₂ are 0 at the same time.

In Formula 1, Ar ₃ is a substituted or unsubstituted arylene group selected from the group consisting of a phenylene group, a biphenylene group, a naphthalene group, a binaphthalene group, an anthracene group, a fluorene group, a chrysene group and a phenanthrene group However, the present invention is not limited thereto.

In Formula 1, Ar ₃ may be an arylene group selected from the group consisting of the following structural formulas, but is not limited thereto.

Further, in the present application, the host material may include a compound represented by the following general formula (7).

(7)

In Formula 7,

At least one of R 1 to R 9 is represented by the following general formula (8), and the others are hydrogen; heavy hydrogen; A halogen group; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkylthio group; A substituted or unsubstituted arylthio group; A substituted or unsubstituted alkylsulfoxy group; A substituted or unsubstituted arylsulfoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted alkylamine group; A substituted or unsubstituted aralkylamine group; A substituted or unsubstituted arylamine group; A substituted or unsubstituted heteroarylamine group; A substituted or unsubstituted aryl group; A substituted or unsubstituted fluorenyl group; A substituted or unsubstituted carbazole group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms;

[Chemical Formula 8]

In Formula 8,

L is a direct bond; A substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group containing at least one of N, O and S atoms,

Ar 1 and Ar 2 are each independently a substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms,

A is O, S or Se.

Further, in the present application, the host material may include a compound represented by the following general formula (9).

[Chemical Formula 9]

In Formula 9,

R1 is a naphthyl group or a biphenyl group,

At least one of R2 to R10 is represented by the following general formula (10), and the others are hydrogen; heavy hydrogen; A halogen group; A nitrile group; A nitro group; A hydroxy group; A substituted or unsubstituted cycloalkyl group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted aryloxy group; A substituted or unsubstituted alkylthio group; A substituted or unsubstituted arylthio group; A substituted or unsubstituted alkylsulfoxy group; A substituted or unsubstituted arylsulfoxy group; A substituted or unsubstituted alkenyl group; A substituted or unsubstituted silyl group; A substituted or unsubstituted boron group; A substituted or unsubstituted alkylamine group; A substituted or unsubstituted aralkylamine group; A substituted or unsubstituted arylamine group; A substituted or unsubstituted heteroarylamine group; A substituted or unsubstituted aryl group; A substituted or unsubstituted fluorenyl group; A substituted or unsubstituted carbazole group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms;

[Chemical formula 10]

In Formula 10,

L is a direct bond; A substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group containing at least one of N, O and S atoms,

Ar 1 and Ar 2 are each independently a substituted or unsubstituted aryl group; Or a substituted or unsubstituted heterocyclic group containing at least one of N, O and S atoms,

A is O, S or Se.

In the compounds according to the present application, the substituents of the above formulas (1) to (10) will be described in more detail as follows.

The alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 12. Specific examples include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, t-butyl, pentyl, hexyl and heptyl.

The alkenyl group may be straight-chain or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 12. Specific examples thereof include, but are not limited to, an alkenyl group having an aryl group such as a stilbenyl group or a styrenyl group.

The alkynyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 12. Specific examples thereof include, but are not limited to, an ethynyl group and a propynyl group.

The cycloalkyl group preferably has 3 to 12 carbon atoms and does not give steric hindrance. Specific examples thereof include, but are not limited to, a cyclopentyl group, a cyclohexyl group, and the like.

The cycloalkenyl group preferably has 3 to 12 carbon atoms, and more specifically, a cyclic compound having ethenylene in a pentagonal or hexagonal ring, but is not limited thereto.

The alkoxy group preferably has 1 to 12 carbon atoms, more specifically, methoxy, ethoxy, isopropyloxy, and the like, but is not limited thereto.

The aryloxy group preferably has 6 to 20 carbon atoms, and more specifically, phenyloxy, cyclohexyloxy, naphthyloxy, diphenyloxy, and the like, but is not limited thereto.

The alkylamine group preferably has 1 to 30 carbon atoms, and more specifically, it may be a methylamine group, a dimethylamine group, an ethylamine group, or a diethylamine group, but is not limited thereto.

The arylamine group preferably has 5 to 30 carbon atoms. More specifically, examples thereof include a phenylamine group, a naphthylamine group, a biphenylamine group, an anthracenylamine group, a 3-methylphenylamine group, a 4-methylnaphthylamine group, Methyl-anthracenylamine group, diphenylamine group, phenylnaphthylamine group, ditolylamine group, phenyltolylamine group, triphenylamine group and the like. But are not limited thereto.

The aryl group may be monocyclic or polycyclic, and the number of carbon atoms is not particularly limited, but is preferably 6 to 40. Examples of the monocyclic aryl group include a phenyl group, a biphenyl group, a terphenyl group and a stilbene group. Examples of the polycyclic aryl group include a naphthyl group, an anthracenyl group, a phenanthrene group, a pyrenyl group, a perylenyl group, A decyl group, and the like, but the present invention is not limited thereto.

The heteroaryl group is a ring group containing a hetero atom such as O, N, S or P, and the number of carbon atoms is not particularly limited, but is preferably 3 to 30 carbon atoms. Examples of the heterocyclic group include carbazole group, thiophene group, furan group, pyrrolyl group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, pyrazazinyl group, quinolinyl group, isoquinoline group , Acridyl groups, and the like, but are not limited thereto.

Examples of the halogen group include, but are not limited to, fluorine, chlorine, bromine, and iodine.

Specific examples of the arylene group include, but are not limited to, a phenylene group, a biphenylene group, a naphthalenylene group, a binaphthalene group, an anthracenylene group, a fluorenylene group, a klychenylene group and a phenanthrenylene group .

Examples of the heterocycloalkyl group include a ring group containing a hetero atom such as N, S or O. [

The term "substituted or unsubstituted" in the present specification means a group selected from the group consisting of deuterium, halogen, alkyl, alkenyl, alkoxy, silyl, arylalkenyl, aryl, Substituted or unsubstituted fluorenyl group and a nitrile group, or has no substituent group.

The substituents of the general formulas (1) to (10) may further be substituted with additional substituents. Examples of the substituents include halogen, alkyl, alkenyl, alkoxy, silyl, arylalkenyl, aryl, heteroaryl, An arylamine group, a fluorenyl group substituted or unsubstituted with an aryl group, a nitrile group, and the like, but are not limited thereto.

Specific examples of the compound represented by the formula (1) include, but are not limited to, the following compounds.

Preferable specific examples of the compound represented by the formula (7) include, but are not limited to, the following compounds.

Preferable specific examples of the compound represented by the formula (9) include, but are not limited to, the following compounds.

Hereinafter, a method for producing the compounds represented by the above Formulas 1 to 10 will be described.

The compounds represented by the above formulas (1) to (10) can be prepared by a general method known in the art such as a condensation reaction and a Suzuki coupling reaction.

The compounds represented by the formulas (1) to (10) may have properties suitable for use as an organic material layer used in an organic light emitting device by introducing various substituents into the core structure represented by the above formula. The compounds represented by Chemical Formulas 1 to 10 may be used in any layer of an organic light emitting device, but may have the following characteristics.

Compounds having a substituted or unsubstituted arylamine group are suitable as a light emitting layer, a hole injecting and hole transporting layer material, and a compound having a heterocyclic group containing N is suitable as an electron injecting layer, an electron transporting layer and a hole blocking layer material.

The conjugation length of the compound and the energy band gap are closely related. Specifically, the longer the conjugation length of the compound, the smaller the energy bandgap. As described above, since the cores of the compounds represented by the general formulas (1) to (10) include a limited conjugation, the energy band gap has a large property from a small property.

Further, by introducing various substituents into the core structure having the above structure, it is possible to synthesize a compound having the intrinsic characteristics of the substituent introduced. For example, the hole injecting layer material and the hole transporting layer materials used in manufacturing the organic light emitting device have energy levels enough to transfer holes along the HOMO, and energy levels enough to block electrons passing through the LUMO from the light emitting layer ≪ / RTI > Particularly, the core structure of the present compound exhibits stable characteristics in terms of electrons, which can contribute to improvement of lifetime of the device. The derivatives prepared by introducing the substituents to be used for the light emitting layer and the electron transporting layer material can be manufactured to have appropriate energy band gaps for various arylamine type dopants, aryl type dopants, metal containing dopants and the like.

Further, by introducing various substituent groups into the core structure, it is possible to finely control the energy band gap, and the characteristics at the interface between the organic materials can be improved and the use of the materials can be diversified.

On the other hand, the compounds represented by Chemical Formulas 1 to 10 have a high glass transition temperature (Tg) and thus are excellent in thermal stability. This increase in thermal stability is an important factor in providing drive stability to the device.

In the present application, the organic material layer may have a multi-layer structure including a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, but is not limited thereto and may have a single layer structure. The organic material layer may be formed using a variety of polymeric materials by a method such as a solvent process such as spin coating, dip coating, doctor blading, screen printing, inkjet printing, Layer.

According to an embodiment of the present invention, there is provided a method of fabricating an organic light emitting device, comprising sequentially forming a cathode, an organic layer, and a cathode on a substrate, wherein at least one of the organic layers includes a host material and an n-type dopant And at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound in the compound constituting the host material is at least 0.5, and the n -Type dopant includes at least one selected from the group consisting of an alkali metal, an alkaline earth metal, and a rare earth metal.

In the present application, the content of the n-type dopant in the host material may be from 0.1 to 1% by weight, and may be from 1 to 10% by weight, but is not limited thereto.

The organic light emitting device of the present application can be produced by a conventional method and material for producing an organic light emitting device, except that one or more organic compound layers are formed using the above-described compounds.

The organic material layer of the organic light emitting device of the present application may have a single layer structure, but may have a multilayer structure in which two or more organic material layers are stacked. For example, the organic electronic device of the present application may have a structure including a hole injecting layer, a hole transporting layer, a light emitting layer, an electron transporting layer, and an electron injecting layer as an organic material layer. However, the structure of the organic light emitting device is not limited thereto, and may include a smaller number of organic layers.

Therefore, in the organic light emitting device of the present application, the organic material layer may include at least one of a hole injection layer, a hole transport layer, and a layer simultaneously injecting holes and transporting holes, and at least one of the layers ≪ / RTI >

Further, the organic material layer may include a light emitting layer, and the light emitting layer may include a compound according to the present application.

In addition, the organic material layer may include at least one of an electron transporting layer, an electron injecting layer, and a layer that simultaneously performs electron transport and electron injection, and one or more of the layers may include a compound according to the present application.

In such an organic layer having a multi-layer structure, the compound according to the present application can be included in a light emitting layer, a layer that simultaneously transports holes and holes, a layer that simultaneously transports holes and light, or a layer that simultaneously transports electrons and light .

For example, the structure of the organic light emitting device of the present application may have a structure as shown in Figs. 1 to 4, but is not limited thereto.

FIG. 1 illustrates a structure of an organic light emitting device in which an anode 102, a light emitting layer 105, and a cathode 107 are sequentially stacked on a substrate 101. In such a structure, the compound according to the present application may be included in the light emitting layer 105.

2 illustrates a structure of an organic light emitting device in which an anode 102, a hole injection / hole transporting and light emitting layer 105, an electron transporting layer 106, and a cathode 107 are sequentially stacked on a substrate 101. In such a structure, the compound according to the present application may be included in the hole injecting / hole transporting and light emitting layer 105.

3 shows a structure of an organic light emitting device in which a substrate 101, an anode 102, a hole injecting layer 103, a hole transporting and emitting layer 105, an electron transporting layer 106, and a cathode 107 are sequentially stacked. . In such a structure, the compound according to the present application may be included in the hole injecting / hole transporting and light emitting layer 105.

4 shows a structure of an organic light emitting device in which a substrate 101, an anode 102, a hole injecting layer 103, a hole transporting layer 104, an electron transporting and emitting layer 105, and a cathode 107 are sequentially laminated. . In such a structure, the compound according to the present application may be contained in the electron transporting and light emitting layer 105.

For example, the organic light emitting device according to the present invention may be formed by using a physical vapor deposition (PVD) method such as sputtering or e-beam evaporation to form a metal or conductive metal oxide or an alloy thereof To form an anode, an organic material layer including a hole injection layer, a hole transporting layer, a light emitting layer, and an electron transporting layer is formed on the anode, and a material which can be used as a cathode is deposited thereon. In addition to such a method, an organic light emitting device may be formed by sequentially depositing a cathode material, an organic material layer, and a cathode material on a substrate.

The organic material layer may have a multi-layer structure including a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, but is not limited thereto and may have a single layer structure. The organic material layer may be formed using a variety of polymeric materials by a method such as a solvent process such as spin coating, dip coating, doctor blading, screen printing, inkjet printing, Layer.

As the anode material, a material having a large work function is preferably used so that hole injection can be smoothly conducted into the organic material layer. Specific examples of the cathode material that can be used in the present application include metals such as vanadium, chromium, copper, zinc, and gold, or alloys thereof; Metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); ZnO: Al or SnO _2: a combination of a metal and an oxide such as Sb; Conductive polymers such as poly (3-methyl compounds), poly [3,4- (ethylene-1,2-dioxy) compounds] (PEDT), polypyrrole and polyaniline.

The negative electrode material is preferably a material having a small work function to facilitate electron injection into the organic material layer. Specific examples of the negative electrode material include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead or alloys thereof; Layer structure materials such as LiF / Al or LiO ₂ / Al, but are not limited thereto.

As the hole injecting material, it is preferable that the highest occupied molecular orbital (HOMO) of the hole injecting material is between the work function of the anode material and the HOMO of the surrounding organic layer. Specific examples of the hole injecting material include metal porphyrine, oligothiophene, arylamine-based organic materials, hexanitrile hexaazatriphenylene-based organic materials, quinacridone-based organic materials, perylene , An anthraquinone, and a conductive polymer of polyaniline and a poly-compound, but the present invention is not limited thereto.

As the hole transporting material, a material capable of transporting holes from the anode or the hole injecting layer to the light emitting layer and having high mobility to holes is suitable. Specific examples include arylamine-based organic materials, conductive polymers, and block copolymers having a conjugated portion and a non-conjugated portion together, but are not limited thereto.

The light emitting material is preferably a material capable of emitting light in the visible light region by transporting and receiving holes and electrons from the hole transporting layer and the electron transporting layer, respectively, and having good quantum efficiency for fluorescence or phosphorescence. Specific examples include 8-hydroxy-quinoline aluminum complex (Alq ₃ ); Carbazole-based compounds; Dimerized styryl compounds; BAlq; 10-hydroxybenzoquinoline-metal compounds; Compounds of the benzoxazole, benzothiazole and benzimidazole series; Polymers of poly (p-phenylenevinylene) (PPV) series; Spiro compounds; Polyfluorene, rubrene, and the like, but are not limited thereto.

As the electron transporting material, a material capable of transferring electrons from the cathode well into the light emitting layer, which is suitable for electrons, is suitable. Specific examples include an Al complex of 8-hydroxyquinoline; Complexes containing Alq ₃ ; Organic radical compounds; Hydroxyflavone-metal complexes, and the like, but are not limited thereto.

The organic light emitting device according to the present invention may be a front emission type, a back emission type, or a both-sided emission type, depending on the material used.

The compound according to the present application may act on a principle similar to that applied to organic light emitting devices in organic electronic devices including organic solar cells, organophotoreceptors, organic transistors and the like.

Hereinafter, preferred embodiments are presented to facilitate understanding of the present application. However, the following embodiments are intended to illustrate the present application, and the scope of the present application is not limited thereby.

<Examples>

&Lt; Example 1 >

A glass substrate (corning 7059 glass) coated with ITO (indium tin oxide) at a thickness of 1,000 Å was immersed in distilled water containing a dispersant and washed with ultrasonic waves. The detergent used was a product of Fischer Co., and distilled water was secondarily filtered using a filter manufactured by Millipore Co. The ITO was washed for 30 minutes and then washed twice with distilled water and ultrasonically cleaned for 10 minutes. After the distilled water was washed, ultrasonic washing was performed in the order of solvent of isopropyl alcohol, acetone, and methanol, and dried.

Hexanitrile hexaazatriphenylene was thermally vacuum deposited on the ITO transparent electrode to a thickness of 500 Å to form a hole injection layer. NPB (400 Å), which is a hole transporting material, was vacuum deposited thereon, and a host H1 and a dopant D1 compound were vacuum deposited as a light emitting layer to a thickness of 300 Å. Subsequently, the E1 compound was vacuum deposited on the electron transport layer to a thickness of 200 Å, and the host compound 1-1 and the dopant Li were thermally vacuum deposited to form an electron injection layer of 150 Å. Aluminum was deposited to a thickness of 2,000 Å on the electron injection layer to form a cathode, thereby preparing an organic light emitting device.

In the above procedure, the deposition rate of the organic material was maintained at 1 Å / sec, the lithium was maintained at about 0.01 Å / s, and the aluminum maintained at 3 to 7 Å / sec.

&Lt; Comparative Example 1 &

The procedure of Example 1 was repeated, except that the following E2 compound was used as a host for the electron injecting layer in Example 1.

[Hexanitrile hexaazatriphenylene]

[NPB]

[H1]

[D1]

[E1]

[E2]

[Formula 1-1]

In the compound of formula (1-1), the difference in electronegativity of Pauling scale between P and O having the greatest electronegativity difference was 1.25. On the other hand, the Pauling scale electronegativity difference between C and N with the largest electronegativity difference in the compound of formula (E2) is ~ 0.5, which is only 1/3 of electronegativity between P and O This can be a good comparison group.

[Table 1]

As shown in Fig. 5, the life span (38h) of Example 1 using Formula 1-1, which is a substance containing -P = O at T90, is about 1.4 times as long as the life span 27h of Comparative Example 1 using E2 , Which can be deduced from the fact that the electric field formed by the dipole moment of P = O suppresses the diffusion of lithium ions.

In addition, as shown in FIG. 6, the voltage increase in the first embodiment is smaller than that of the first comparative example. It can be deduced that the material of the formula 1-1 suppresses diffusion of lithium ions, .

As described above, the organic light emitting device according to the present application includes a cathode, a cathode, and at least one organic layer disposed between the anode and the cathode, and changes the dipole moment of the compound contained in the organic layer The lifetime characteristics of the organic light emitting device can be greatly improved and the stability of the organic light emitting device can be improved.

Claims (18)

An organic light emitting device comprising a cathode, a cathode, and at least one organic layer disposed between the anode and the cathode,
At least one of the organic material layers includes a host material and an n-type dopant,
Wherein the host material comprises a compound represented by the following Formula 1,
Wherein at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound is 0.5 or more in the compound constituting the host material,
Wherein the n-type dopant comprises at least one selected from the group consisting of Mg, Ca, Li, Na, K and Cs.
[Chemical Formula 1]

In Formula 1,
And X ₁ is CR3, and X ₂ is CR4, X ₃ is CR5, and X ₄ is CR6, and a Y ₁ is CR7, and Y ₂ is CR8, and Y ₃ is CR9, and Y ₄ is CR10, R3 to R10 are each independently hydrogen or represented by the following formula (1A), at least one of R3 to R10 is represented by the following formula (1A)
&Lt; EMI ID =

R1 and R2 are connected to each other to form or form an aromatic monocyclic ring,
A is O,
Ar ₁ and Ar ₂ are each independently an aryl group;
Ar ₃ is an arylene group substituted or unsubstituted with an alkyl group or an aryl group. The compound according to claim 1, wherein the chemical bond between the atoms having an electronegativity difference of not less than 0.5 is -O-Li, -N-Li, -C═O, -CO-, -CF 2 - NF, -Si = O, -Si-O-, -Si-F, -Si-Cl, -Si-Br, -P = O, -PO-, -PF, -P- Wherein the organic compound is at least one compound selected from the group consisting of organic compounds. delete The organic electroluminescent device according to claim 1, wherein the organic layer includes a light emitting layer,
And an organic material layer including the host material and an n-type dopant between the cathode and the light emitting layer. The organic electroluminescent device according to claim 1, wherein the organic layer includes a light emitting layer,
An electron transport layer between the cathode and the light emitting layer,
Wherein the electron transport layer comprises the host material and an n-type dopant. delete The organic electroluminescent device according to claim 1, wherein the compound represented by Formula 1 is represented by Formula 2:
(2)

In Formula 2,
X ₁ to X ₄ , and Y ₁ to Y ₄ are as defined in Formula 1,
(N) In n ₁ , N represents a nitrogen atom, which indicates that the nitrogen atom can substitute for the carbon atom in the benzene ring,
(N) n ₁ , n ₁ is 0,
R &lt; ₁₁ &gt; is hydrogen,
k ₁ is an integer of 0 to 4; delete delete The organic electroluminescent device according to claim 1, wherein the compound represented by Formula 1 is represented by Formula 6:
[Chemical Formula 6]

In Formula 6,
Ar ₁ to Ar ₃ , and A are the same as defined in Formula 1,
m ₁ is an integer of 0 to 4, and m ₂ is an integer of 0 to 4, except that m ₁ and m ₂ are 0 at the same time. The organic electroluminescent device according to claim 1, wherein the compound represented by Formula 1 is represented by any one of the following formulas:

delete delete delete delete Sequentially forming an anode, an organic layer and a cathode on a substrate,
Wherein at least one layer of the organic material layer includes a host material and an n-type dopant,
Wherein the host material comprises a compound represented by the following Formula 1,
Wherein at least one chemical bond between atoms having a difference in electronegativity between atoms constituting the compound is 0.5 or more in the compound constituting the host material,
Wherein the n-type dopant comprises at least one selected from the group consisting of Mg, Ca, Li, Na, K and Cs.
[Chemical Formula 1]

In Formula 1,
And X ₁ is CR3, and X ₂ is CR4, X ₃ is CR5, and X ₄ is CR6, and a Y ₁ is CR7, and Y ₂ is CR8, and Y ₃ is CR9, and Y ₄ is CR10, R3 to R10 are each independently hydrogen or represented by the following formula (1A), at least one of R3 to R10 is represented by the following formula (1A)
&Lt; EMI ID =

R1 and R2 are connected to each other to form or form an aromatic monocyclic ring,
A is O,
Ar ₁ and Ar ₂ are each independently an aryl group;
Ar ₃ is an arylene group substituted or unsubstituted with an alkyl group or an aryl group. [Claim 16] The method of claim 16, wherein the content of the n-type dopant in the host material is 0.1 to 1 wt% or 1 to 10 wt%. 17. The method of claim 16, wherein the organic material layer formed by co-evaporating the host material and the n-type dopant is an electron transport layer.

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