KR20210073439A - Organic light emitting device - Google Patents

Abstract

The present invention provides an organic light emitting element having improved driving voltage, efficiency, and lifetime. The organic light emitting element includes a positive electrode, a first hole accelerating layer including a first host and a first dopant, a first hole transport layer, a second hole accelerating layer including a second host and a second dopant, a second hole transport layer, a light emitting layer, an electron transport layer, and a negative electrode.

Description

Organic light emitting device

The present invention relates to an organic light emitting device having improved driving voltage, efficiency, and lifetime.

In general, the organic light emitting phenomenon refers to a phenomenon in which electric energy is converted into light energy using an organic material. The organic light emitting device using the organic light emitting phenomenon has a wide viewing angle, excellent contrast, fast response time, and excellent luminance, driving voltage, and response speed characteristics, and thus many studies are being conducted.

An organic light emitting device generally has a structure including an anode and a cathode and an organic material layer between the anode and the cathode. The organic layer is often formed of a multi-layered structure composed of different materials in order to increase the efficiency and stability of the organic light-emitting device, and may include, for example, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and the like. In the structure of the organic light emitting device, when a voltage is applied between the two electrodes, holes are injected into the organic material layer from the anode and electrons from the cathode are injected into the organic material layer. When the injected holes and electrons meet, excitons are formed, and the excitons When it falls back to the ground state, it lights up.

In the organic light emitting device as described above, the development of an organic light emitting device having improved driving voltage, efficiency, and lifespan is continuously required.

Korean Patent Publication No. 10-2000-0051826

The present invention relates to an organic light emitting device having improved driving voltage, efficiency, and lifetime.

The present invention provides the following organic light emitting device:

anode,

a first hole accelerating layer comprising a first host and a first dopant;

a first hole transport layer;

a second hole accelerating layer comprising a second host and a second dopant;

a second hole transport layer;

light emitting layer,

an electron transport layer, and

In the organic light emitting device comprising a cathode,

The first dopant and the second dopant are the same material as each other,

The second host is a compound represented by the following formula (1),

The second hole transport layer comprises the second host,

Organic light emitting device:

[Formula 1]

In Formula 1,

each R is independently substituted or unsubstituted C _1-60 alkyl, or substituted or unsubstituted C _6-60 aryl,

L ₁ and L ₂ are each independently a single bond; Or a substituted or unsubstituted C _6-60 arylene,

Ar ₁ is a substituted or unsubstituted C _6-60 aryl,

Ar ₂ is substituted or unsubstituted C _6-60 aryl; or substituted or unsubstituted adamantyl.

The organic light emitting device described above has excellent driving voltage, efficiency, and lifetime.

1 shows a substrate 1, an anode 2, a first hole accelerating layer 3, a first hole transport layer 4, a second hole accelerating layer 5, a second hole transport layer 6, a light emitting layer ( 7), an example of an organic light emitting device including an electron transport layer 8, and a cathode 9 is shown.

Hereinafter, it will be described in more detail to help the understanding of the present invention.

또는

는 다른 치환기에 연결되는 결합을 의미한다. In this specification,

or

means a bond connected to another substituent.

As used herein, the term "substituted or unsubstituted" refers to deuterium; halogen group; nitrile group; nitro group; hydroxyl group; carbonyl group; ester group; imid; amino group; phosphine oxide group; alkoxy group; aryloxy group; alkyl thiooxy group; arylthioxy group; an alkyl sulfoxy group; arylsulfoxy group; silyl group; boron group; an alkyl group; cycloalkyl group; alkenyl group; aryl group; aralkyl group; aralkenyl group; an alkylaryl group; an alkylamine group; an aralkylamine group; heteroarylamine group; arylamine group; an arylphosphine group; or N, O, and S atom means that it is substituted or unsubstituted with one or more substituents selected from the group consisting of a heterocyclic group containing one or more atoms, or substituted or unsubstituted with two or more substituents connected among the above-exemplified substituents . For example, "a substituent in which two or more substituents are connected" may be a biphenyl group. That is, the biphenyl group may be an aryl group, and may be interpreted as a substituent in which two phenyl groups are connected.

In the present specification, the number of carbon atoms in the carbonyl group is not particularly limited, but preferably 1 to 40 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, in the ester group, the oxygen of the ester group may be substituted with a linear, branched or cyclic alkyl group having 1 to 25 carbon atoms or an aryl group having 6 to 25 carbon atoms. Specifically, it may be a compound of the following structural formula, but is not limited thereto.

In the present specification, the number of carbon atoms of the imide group is not particularly limited, but it is preferably from 1 to 25 carbon atoms. Specifically, it may be a compound having the following structure, but is not limited thereto.

In the present specification, the silyl group specifically includes a trimethylsilyl group, a triethylsilyl group, a t-butyldimethylsilyl group, a vinyldimethylsilyl group, a propyldimethylsilyl group, a triphenylsilyl group, a diphenylsilyl group, a phenylsilyl group, and the like. However, the present invention is not limited thereto.

In the present specification, the boron group specifically includes, but is not limited to, a trimethylboron group, a triethylboron group, a t-butyldimethylboron group, a triphenylboron group, a phenylboron group, and the like.

In the present specification, examples of the halogen group include fluorine, chlorine, bromine or iodine.

In the present specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to an exemplary embodiment, the number of carbon atoms in the alkyl group is 1 to 20. According to another exemplary embodiment, the alkyl group has 1 to 10 carbon atoms. According to another exemplary embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n -pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl , n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2 -Dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl and the like, but are not limited thereto.

In the present specification, the alkenyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to an exemplary embodiment, the carbon number of the alkenyl group is 2 to 20. According to another exemplary embodiment, the carbon number of the alkenyl group is 2 to 10. According to another exemplary embodiment, the alkenyl group has 2 to 6 carbon atoms. Specific examples include vinyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 3-methyl-1- Butenyl, 1,3-butadienyl, allyl, 1-phenylvinyl-1-yl, 2-phenylvinyl-1-yl, 2,2-diphenylvinyl-1-yl, 2-phenyl-2-( Naphthyl-1-yl)vinyl-1-yl, 2,2-bis(diphenyl-1-yl)vinyl-1-yl, stilbenyl group, styrenyl group, and the like, but are not limited thereto.

In the present specification, the cycloalkyl group is not particularly limited, but preferably has 3 to 60 carbon atoms, and according to an exemplary embodiment, the cycloalkyl group has 3 to 30 carbon atoms. According to another exemplary embodiment, the carbon number of the cycloalkyl group is 3 to 20. According to another exemplary embodiment, the cycloalkyl group has 3 to 6 carbon atoms. Specifically, cyclopropyl, cyclobutyl, cyclopentyl, 3-methylcyclopentyl, 2,3-dimethylcyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3, 4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, and the like, but is not limited thereto.

In the present specification, the aryl group is not particularly limited, but preferably has 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to an exemplary embodiment, the carbon number of the aryl group is 6 to 30. According to an exemplary embodiment, the carbon number of the aryl group is 6 to 20. The aryl group may be a monocyclic aryl group such as a phenyl group, a biphenyl group, or a terphenyl group, but is not limited thereto. The polycyclic aryl group may be a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, and the like, but is not limited thereto.

등이 될 수 있다. 다만, 이에 한정되는 것은 아니다.In the present specification, the fluorenyl group may be substituted, and two substituents may be bonded to each other to form a spiro structure. When the fluorenyl group is substituted,

etc. can be However, the present invention is not limited thereto.

In the present specification, the heterocyclic group is a heterocyclic group including at least one of O, N, Si and S as a heterogeneous element, and the number of carbon atoms is not particularly limited, but it is preferably from 2 to 60 carbon atoms. Examples of the heterocyclic group include a thiophene group, a furan group, a pyrrole group, an imidazole group, a thiazole group, an oxazole group, an oxadiazole group, a triazole group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazine group, a triazole group, Acridyl group, pyridazine group, pyrazinyl group, quinolinyl group, quinazoline group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, isoquinoline group , indole group, carbazole group, benzooxazole group, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, thiazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzothiazolyl group, a phenothiazinyl group, and a dibenzofuranyl group, but are not limited thereto.

In the present specification, the aryl group in the aralkyl group, the aralkenyl group, the alkylaryl group, and the arylamine group is the same as the example of the aryl group described above. In the present specification, the alkyl group among the aralkyl group, the alkylaryl group, and the alkylamine group is the same as the example of the above-described alkyl group. In the present specification, as for heteroaryl among heteroarylamines, the description of the above-described heterocyclic group may be applied. In the present specification, the alkenyl group among the aralkenyl groups is the same as the above-described examples of the alkenyl group. In the present specification, the description of the above-described aryl group may be applied except that arylene is a divalent group. In the present specification, the description of the above-described heterocyclic group may be applied, except that heteroarylene is a divalent group. In the present specification, the hydrocarbon ring is not a monovalent group, and the description of the above-described aryl group or cycloalkyl group may be applied except that it is formed by combining two substituents. In the present specification, the heterocyclic group is not a monovalent group, and the description of the above-described heterocyclic group may be applied, except that it is formed by combining two substituents.

Hereinafter, the present invention will be described in detail for each configuration.

positive and negative

The anode and cathode used in the present invention mean electrodes used in an organic light emitting device.

As the anode material, a material having a large work function is generally preferred so that holes can be smoothly injected into the organic material layer. Specific examples of the anode material include metals such as vanadium, chromium, copper, zinc, gold, or alloys thereof; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO _{2 :Sb;} conductive polymers such as poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene](PEDOT), polypyrrole, and polyaniline, but are not limited thereto.

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

first hole accelerating layer

The organic light emitting diode according to the present invention includes a first hole accelerating layer including a first host and a first dopant on the anode. Preferably, the first hole accelerating layer is adjacent to the anode.

For a high-efficiency organic light emitting diode, it is necessary to use a material in which electrons move quickly. However, in this case, a high driving voltage is required, and accordingly, the light emitting zone is biased toward the hole transport layer in the light emitting layer, so that the driving voltage is high and the lifespan is short. Ideally, the light emitting zone should be evenly distributed throughout the light emitting layer, but it is not easy to balance holes and electrons. Accordingly, in the present invention, the first hole accelerating layer and the second hole accelerating layer to be described later are provided to accelerate the injection of holes from the anode to the light emitting layer or facilitate movement, thereby adjusting the balance of holes and electrons in the light emitting layer, and driving voltage It can lower the energy consumption, increase the efficiency, and also improve the lifespan. In addition, as will be described later for the above, by using a compound in which the first dopant included in the first hole accelerating layer and the second dopant included in the second hole accelerating layer are identical to each other, holes in the light emitting layer and The electron balance can be adjusted.

The first host is not particularly limited as long as it is a host material used in a hole injection layer of a conventional organic light emitting device. For example, the first host is the following compound.

In addition, the first host is a compound different from the second host of the second hole accelerating layer to be described later. In addition, the first host and the first dopant are different compounds.

The first dopant is not particularly limited as long as it is a dopant material used in a hole injection layer of a conventional organic light emitting device. For example, the first dopant is the following compound.

Preferably, in the first hole accelerating layer, a weight ratio of the first host to the first dopant is 90:10 to 99:1. In addition, the first hole accelerating layer is composed of the first host and the first dopant, in other words, a material other than the first host and the first dopant is substantially not included in the first hole accelerating layer. does not

first hole transport layer

The organic light emitting diode according to the present invention may include a first hole transport layer on the first hole accelerating layer. Preferably, the first hole transport layer is adjacent to the first hole accelerating layer.

The hole transport layer is a layer that receives holes from the first hole accelerating layer and transports holes to a second hole accelerating layer to be described later, and a material having high hole mobility is suitable.

Specific examples of the material constituting the hole transport layer include, but are not limited to, an arylamine-based organic material, a conductive polymer, and a block copolymer having a conjugated portion and a non-conjugated portion together.

Preferably, the hole transport layer is made of the same material as the first host of the first hole acceleration layer. In other words, a material other than the first host is not substantially included in the hole transport layer. As described above, since the hole transport layer is made of the same material as the first host of the first hole accelerating layer, the transport of holes becomes easier, and it is easy to adjust the balance of holes and electrons in the light emitting layer.

second hole accelerating layer

The organic light emitting device according to the present invention includes a second hole accelerating layer including a second host and a second dopant on the hole transport layer. Preferably, the second hole accelerating layer is adjacent to the hole transport layer.

Similar to the first hole accelerating layer, the second hole accelerating layer receives holes from the hole transport layer and accelerates hole injection or facilitates movement to the emission layer, thereby controlling the balance of holes and electrons in the emission layer.

Preferably, a difference between the band gap of the first host and the second host is 0.3 eV or less.

Preferably, as the second host, a compound represented by Formula 1 is used.

In the above formula (1), preferably, all R are methyl, or all are phenyl.

Preferably, _{each L 1} is independently a single bond or phenylene.

Preferably, _{each L 2} is independently a single bond, phenylene, biphenyldiyl, or terphenyldiyl.

Preferably, Ar ₁ is phenyl, biphenylyl, terphenylyl, naphthyl, phenanthrenyl, dimethylfluorenyl, or diphenylfluorenyl.

Preferably, Ar ₂ is substituted or unsubstituted spirobifluorenyl; substituted or unsubstituted dimethylfluorenyl; substituted or unsubstituted diphenylfluorenyl; substituted or unsubstituted triphenylenyl; or substituted or unsubstituted adamantyl. More preferably, Ar ₂ is any one selected from the group consisting of:

Representative examples of the compound represented by Formula 1 are as follows:

Meanwhile, as described above, the second dopant uses the same material as the first dopant of the first hole accelerating layer. In addition, the second host and the second dopant are different compounds.

Preferably, in the second hole accelerating layer, a weight ratio of the second host to the second dopant is 90:10 to 99:1. In addition, the second hole accelerating layer is composed of the second host and the second dopant, in other words, a material other than the second host and the second dopant is substantially not included in the second hole accelerating layer. does not

second hole transport layer

The organic light emitting device according to the present invention includes the second hole accelerating layer and the second hole transport layer. Preferably, the second hole transport layer is adjacent to the second hole accelerating layer. In addition, the second hole transport layer includes the same material as the second host.

As described above, since the second hole transport layer is made of the same material as the second host of the second hole accelerating layer, the transport of holes becomes easier, and it is easy to control the balance of holes and electrons in the light emitting layer. Preferably, the second hole transport layer is composed of the second host, in other words, a material other than the second host is substantially not included in the second hole transport layer.

light emitting layer

The organic light emitting device according to the present invention includes a light emitting layer between the second hole transport layer and the electron transport layer.

The light emitting layer refers to a layer capable of emitting light in the visible ray region by combining holes and electrons transferred from the anode and the cathode. In general, the light emitting layer includes a host material and a dopant material. In addition, as described above, the balance of holes and electrons in the light emitting layer is adjusted by the first hole accelerating layer and the second hole accelerating layer according to the present invention, so that the driving voltage is lowered, and the luminous efficiency and lifespan can be improved. .

The host material may be a condensed aromatic ring derivative or a heterocyclic compound containing compound. Specifically, condensed aromatic ring derivatives include anthracene derivatives, pyrene derivatives, naphthalene derivatives, pentacene derivatives, phenanthrene compounds, fluoranthene compounds, and the like, and heterocyclic-containing compounds include carbazole derivatives, dibenzofuran derivatives, ladder-type compounds. Furan compounds, pyrimidine derivatives, and the like, but are not limited thereto.

The dopant material is not particularly limited as long as it is a material used in an organic light emitting device. Examples include an aromatic amine derivative, a strylamine compound, a boron complex, a fluoranthene compound, and a metal complex. Specifically, the aromatic amine derivative is a condensed aromatic ring derivative having a substituted or unsubstituted arylamino group, and includes pyrene, anthracene, chrysene, and periflanthene having an arylamino group, and the styrylamine compound is a substituted or unsubstituted derivative. It is a compound in which at least one arylvinyl group is substituted in the arylamine, and one or two or more substituents selected from the group consisting of an aryl group, a silyl group, an alkyl group, a cycloalkyl group and an arylamino group are substituted or unsubstituted. Specifically, there are styrylamine, styryldiamine, styryltriamine, styryltetraamine, and the like, but is not limited thereto. In addition, the metal complex includes an iridium complex, a platinum complex, and the like, but is not limited thereto.

Meanwhile, if necessary, the organic light emitting device according to the present invention may include an electron suppressing layer adjacent to the anode direction of the light emitting layer. The electron suppression layer is a layer that inhibits the transfer of electrons from the light emitting layer to the anode, and is not particularly limited as long as it is a material for the electron suppression layer used in an organic light emitting device.

electron transport layer

The organic light emitting device according to the present invention may include an electron transport layer between the light emitting layer and the cathode.

The electron transport layer is a layer that receives electrons from the electron injection layer formed on the cathode or the cathode and transports electrons to the light emitting layer. As an electron transport material, as an electron transport material, electrons are well injected from the cathode and transferred to the light emitting layer. Materials with high mobility are suitable.

Specific examples of the electron transport material 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 electron transport layer may be used with any desired cathode material as used in accordance with the prior art. In particular, examples of suitable cathode materials are conventional materials having a low work function and followed by a layer of aluminum or silver. Specifically cesium, barium, calcium, ytterbium and samarium, followed in each case by an aluminum layer or a silver layer.

electron injection layer

The organic light emitting diode according to the present invention may further include an electron injection layer between the electron transport layer and the cathode, if necessary.

The electron injection layer is a layer that injects electrons from the electrode, has the ability to transport electrons, has an electron injection effect from the cathode, an excellent electron injection effect on the light emitting layer or the light emitting material, and hole injection of excitons generated in the light emitting layer. It is preferable to use a compound which prevents movement to a layer and is excellent in the ability to form a thin film.

Specific examples of the material that can be used as the electron injection layer include fluorenone, anthraquinodimethane, diphenoquinone, thiopyran dioxide, oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, preole nylidene methane, anthrone, and the like, derivatives thereof, metal complex compounds, nitrogen-containing 5-membered ring derivatives, and the like, but are not limited thereto.

Examples of the metal complex compound include 8-hydroxyquinolinato lithium, bis(8-hydroxyquinolinato)zinc, bis(8-hydroxyquinolinato)copper, bis(8-hydroxyquinolinato)manganese, Tris(8-hydroxyquinolinato)aluminum, tris(2-methyl-8-hydroxyquinolinato)aluminum, tris(8-hydroxyquinolinato)gallium, bis(10-hydroxybenzo[h] Quinolinato) beryllium, bis (10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-quinolinato) chlorogallium, bis (2-methyl-8-quinolinato) ( o-crezolato)gallium, bis(2-methyl-8-quinolinato)(1-naphtolato)aluminum, bis(2-methyl-8-quinolinato)(2-naphtolato)gallium, etc. However, the present invention is not limited thereto.

organic light emitting device

The structure of the organic light emitting device according to the present invention is illustrated in FIG. 1 . 1 shows a substrate 1, an anode 2, a first hole accelerating layer 3, a first hole transport layer 4, a second hole accelerating layer 5, a second hole transport layer 6, a light emitting layer ( 7), an example of an organic light emitting device including an electron transport layer 8, and a cathode 9 is shown.

The organic light emitting device according to the present invention may be manufactured by sequentially stacking the above-described components. At this time, by using a PVD (physical vapor deposition) method such as sputtering or e-beam evaporation, a metal or conductive metal oxide or an alloy thereof is deposited on a substrate to form an anode. And, after forming each of the above-mentioned layers thereon, it can be prepared by depositing a material that can be used as a cathode thereon. In addition to the above method, an organic light emitting device may be manufactured by sequentially depositing the anode material on the substrate from the cathode material in the reverse order of the above configuration (WO 2003/012890). In addition, the light emitting layer may be formed by a solution coating method as well as a vacuum deposition method for the host and dopant. Here, the solution application method refers to spin coating, dip coating, doctor blading, inkjet printing, screen printing, spray method, roll coating, and the like, but is not limited thereto.

On the other hand, the organic light emitting device according to the present invention may be a top emission type, a back emission type, or a double-sided emission type depending on the material used.

Hereinafter, preferred examples are presented to help the understanding of the present invention. However, the following examples are only provided for easier understanding of the present invention, and the content of the present invention is not limited thereto.

[Production Example]

Preparation Example 1: Preparation of compound HTL-A

Compound A (7.2 g, 18.21 mmol) and compound a1 (6.72 g, 18.58 mmol) were completely dissolved in toluene (150 mL) in a 500 mL round bottom flask in a nitrogen atmosphere, and NaOtBu (2.45 g, 25.50 mmol) was added thereto. , bis (tri-tert-butylphosphine) palladium (0) (0.09 g, 0.18 mmol) was added thereto, followed by heating and stirring for 3 hours. After lowering the temperature to room temperature and removing the base by filtration, toluene was concentrated under reduced pressure and recrystallized from ethyl acetate (250 mL) to prepare compound HTL-A (10.25 g, yield: 83.3%).

MS: [M+H] ⁺ = 676

Preparation Example 2: Preparation of compound HTL-B

Compound B (10.2 g, 25.67 mmol) and compound a1 (9.47 g, 26.19 mmol) were completely dissolved in toluene (170 mL) in a 500 mL round-bottom flask in a nitrogen atmosphere, and NaOtBu (3.45 g, 35.94 mmol) was added thereto. , bis (tri-tert-butylphosphine) palladium (0) (0.13 g, 0.26 mmol) was added, followed by heating and stirring for 3 hours. After lowering the temperature to room temperature and removing the base by filtration, toluene was concentrated under reduced pressure and recrystallized from ethyl acetate (200 mL) to prepare compound HTL-B (15.5 g, yield: 89.1%).

MS: [M+H] ⁺ = 678

Preparation Example 3: Preparation of compound HTL-C

Compound C (8.5 g, 27.7 mmol) and compound a2 (15.9 g, 28.2 mmol) were completely dissolved in tetrahydrofuran (280 mL) in a 500 ml round bottom flask in a nitrogen atmosphere, and then 2 M aqueous potassium carbonate solution (140 mL) was added. After addition, tetrakis-(triphenylphosphine)palladium (0.96 g, 0.83 mmol) was added, followed by heating and stirring for 4 hours. The temperature was lowered to room temperature, the water layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from ethyl acetate (180 mL) to prepare compound HTL-C (15.43 g, 84%).

MS: [M+H] ⁺ = 664

Preparation Example 4: Preparation of compound HTL-D

Compound D (7.6 g, 26.1 mmol) and compound a2 (15.0 g, 26.6 mmol) were completely dissolved in tetrahydrofuran (260 mL) in a 500 ml round-bottom flask in a nitrogen atmosphere, and then 2 M aqueous potassium carbonate solution (130 mL) was added. After addition, tetrakis-(triphenylphosphine)palladium (0.90 g, 0.78 mmol) was added, followed by heating and stirring for 4 hours. The temperature was lowered to room temperature, the water layer was removed, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and recrystallized from ethyl acetate (160 mL) to prepare compound HTL-D (12.73 g, 75.3%).

MS: [M+H] ⁺ = 648

[Example]

Example 1-1

A glass substrate coated with indium tin oxide (ITO) to a thickness of 1300 Å was placed in distilled water in which detergent was dissolved and washed with ultrasonic waves. At this time, a product manufactured by Fischer Co. was used as the detergent, and distilled water that was secondarily filtered with a filter manufactured by Millipore Co. was used as the distilled water. After washing ITO for 30 minutes, ultrasonic cleaning was performed for 10 minutes by repeating twice with distilled water. After washing with distilled water, ultrasonic washing was performed with a solvent of isopropyl alcohol, acetone, and methanol, dried, and then transported to a plasma cleaner. In addition, after cleaning the substrate for 5 minutes using oxygen plasma, the substrate was transported to a vacuum evaporator.

On the ITO transparent electrode prepared as described above, the following HTL1 compound and the following P-Dopant compound were vacuum-deposited in a weight ratio of 98:2 to form a first hole acceleration layer having a thickness of 100 Å.

On the first hole accelerating layer, the HTL1 compound was vacuum deposited to form a hole transport layer having a thickness of 1150 Å. On the hole transport layer, the HTL-A compound and the P-Dopant compound prepared above were vacuum-deposited at a weight ratio of 99:1 to form a second hole accelerating layer having a thickness of 100 Å. On the second hole accelerating layer, the HTL-A compound prepared above was vacuum-deposited to form a second hole transport layer having a thickness of 200 Å. On the second hole transport layer, the following EBL compound was vacuum-deposited to form an electron blocking layer having a thickness of 150 Å. On the electron suppression layer, the following P-Host compound, the following N-Host compound, and the following GD compound were vacuum-deposited at a weight ratio of 47:47:6 to form an emission layer having a thickness of 350 Å. On the light emitting layer, the following HBL compound was vacuum deposited to form a hole blocking layer having a thickness of 50 Å. On the hole blocking layer, the following ETL compound and the following LiQ compound were vacuum-deposited in a weight ratio of 1:1 to form an electron transport layer having a thickness of 300 Å. On the electron transport layer, the following LiQ compound was vacuum deposited to form an electron injection layer with a thickness of 15 Å. An organic light emitting device was manufactured by depositing aluminum having a thickness of 1,000 Å on the electron injection layer to form a cathode.

In the above process, the deposition rate of the organic material was maintained at 0.4 ~ 0.7 Å/sec, the deposition rate of aluminum was maintained at 2 Å/sec, and the vacuum degree during deposition was maintained at 2×10 ^-7 ~ 5×10 ^-6 torr Thus, an organic light emitting device was manufactured.

On the other hand, the band gaps of the HTL-A compound and the HTL-A compound used were 3.07 eV and 3.30 eV, respectively.

Examples 1-2 to 1-8 and Comparative Examples 1-1 to 1-7

Prepared in the same manner as in Example 1-1, except that the first hole accelerating layer, the second hole accelerating layer, the second hole transport layer and / or the electron suppression layer was changed to the configuration and thickness of Table 1 below, A light emitting device was manufactured.

first hole accelerating layer (Å) Second hole accelerating layer (Å) Second hole transport layer (Å) Electron suppression layer (Å) Example 1-1 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (1wt%) (100) HTL-A (200) EBL (150) Example 1-2 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (2wt%) (100) HTL-A (200) EBL (150) Examples 1-3 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (3wt%) (100) HTL-A (200) EBL (150) Examples 1-4 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (4wt%) (100) HTL-A (200) EBL (150) Examples 1-5 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (1wt%) (100) HTL-A (350) - Examples 1-6 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (2wt%) (100) HTL-A (350) - Examples 1-7 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (3wt%) (100) HTL-A (350) - Examples 1-8 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (4wt%) (100) HTL-A (350) - Comparative Example 1-1 HTL1 (100) HTL-A (300) - EBL (150) Comparative Example 1-2 HTL1 & P-Dopant (2 wt%) (100) HTL-A (300) - EBL (150) Comparative Example 1-3 HTL1 & P-Dopant (2 wt%) (100) HTL-A (450) - - Comparative Example 1-4 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (1wt%) (100) - - Comparative Example 1-5 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (2wt%) (100) - - Comparative Example 1-6 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (3wt%) (100) - - Comparative Example 1-7 HTL1 & P-Dopant (2 wt%) (100) HTL-A & P-Dopant (4wt%) (100) - -

Driving voltage (V), luminance (cd/A), luminous efficiency (lm/w), external quantum efficiency (external quantum efficiency) at a current density of ^{10 mA/cm 2} for the organic light emitting devices prepared in Examples and Comparative Examples , QE), and the results of measuring color coordinates are shown in Table 2 below. The external quantum efficiency was calculated as (number of emitted photons)/(number of injected charge carriers).

V cd/A lm/w QE CIE-x CIE-y Example 1-1 3.77 64.07 53.39 18.83 0.362 0.609 Example 1-2 3.62 63.43 55.07 18.65 0.363 0.608 Examples 1-3 3.54 63.16 56.00 18.57 0.363 0.609 Examples 1-4 3.50 63.14 56.60 18.55 0.363 0.609 Examples 1-5 3.73 65.33 54.94 19.12 0.354 0.616 Examples 1-6 3.60 64.70 56.50 18.94 0.354 0.616 Examples 1-7 3.52 64.26 57.35 18.81 0.354 0.616 Examples 1-8 3.48 64.18 57.95 18.79 0.353 0.617 Comparative Example 1-1 4.52 58.24 40.46 16.83 0.346 0.623 Comparative Example 1-2 4.07 64.91 50.00 19.06 0.362 0.609 Comparative Example 1-3 4.08 69.33 53.33 20.33 0.361 0.611 Comparative Example 1-4 3.64 59.06 51.00 17.31 0.360 0.611 Comparative Example 1-5 3.50 55.00 49.39 16.13 0.360 0.611 Comparative Example 1-6 3.44 52.60 47.99 15.43 0.360 0.611 Comparative Example 1-7 3.42 50.74 46.66 14.88 0.360 0.611

As shown in Table 2, it was confirmed that the performance of the organic light emitting device according to the present invention was significantly improved. Specifically, in Comparative Examples 1-1 to 1-3, the first hole accelerating layer and the second hole accelerating layer do not include the same dopant, so that the performance of the organic light emitting device is lower than that of the organic light emitting device according to the present invention. fell, and in Comparative Examples 1-4 to 1-7, the second hole transport layer adjacent to the second hole accelerating layer and made of the same material as the second host of the second hole accelerating layer did not exist, so the performance of the organic light emitting device It was confirmed that this was inferior to the organic light emitting device according to the present invention.

Examples 2-1 to 4-2 and Comparative Examples 2-1 to 4-1

Prepared in the same manner as in Example 1-1, except that the first hole accelerating layer, the second hole accelerating layer, the second hole transport layer and / or the electron suppression layer was changed to the configuration and thickness of Table 3 below, A light emitting device was manufactured.

first hole accelerating layer (Å) Second hole accelerating layer (Å) Second hole transport layer (Å) Electron suppression layer (Å) Example 2-1 HTL1 & P-Dopant (2wt%) (100) HTL-B & P-Dopant (2wt%) (100) HTL-B (200) EBL (150) Example 2-2 HTL1 & P-Dopant (2wt%) (100) HTL-B & P-Dopant (2wt%) (100) HTL-B (350) - Comparative Example 2-1 HTL1 (100) HTL-B (300) - EBL (150) Comparative Example 2-2 HTL1 & P-Dopant (2wt%) (100) HTL-B (300) - EBL (150) Example 3-1 HTL1 & P-Dopant (2wt%) (100) HTL-C & P-Dopant (2wt%) (100) HTL-C (200) EBL (150) Example 3-2 HTL1 & P-Dopant (2wt%) (100) HTL-C & P-Dopant (2wt%) (100) HTL-C (350) - Comparative Example 3-1 HTL1 (100) HTL-C (300) - EBL (150) Comparative Example 3-2 HTL1 & P-Dopant (2wt%) (100) HTL-C (300) - EBL (150) Example 4-1 HTL1 & P-Dopant (2wt%) (100) HTL-D & P-Dopant (2wt%) (100) HTL-D (200) EBL (150) Example 4-2 HTL1 & P-Dopant (2wt%) (100) HTL-D & P-Dopant (2wt%) (100) HTL-D (350) - Comparative Example 4-1 HTL1 (100) HTL-D (300) - EBL (150)

Driving voltage (V), luminance (cd/A), luminous efficiency (lm/w), external quantum efficiency (external quantum efficiency) at a current density of ^{10 mA/cm 2} for the organic light emitting devices prepared in Examples and Comparative Examples , QE), and the results of measuring color coordinates are shown in Table 4 below. The external quantum efficiency was calculated as (number of emitted photons)/(number of injected charge carriers).

V cd/A lm/w QE CIE-x CIE-y Example 2-1 4.16 68.02 51.42 19.82 0.356 0.615 Example 2-2 4.05 67.09 52.07 19.58 0.358 0.613 Comparative Example 2-1 4.72 58.60 39.04 16.99 0.349 0.620 Comparative Example 2-2 4.17 55.43 44.25 16.02 0.351 0.620 Example 3-1 4.09 65.68 50.49 19.13 0.356 0.615 Example 3-2 3.99 64.68 50.91 18.86 0.357 0.614 Comparative Example 3-1 4.69 65.65 43.95 19.04 0.350 0.619 Comparative Example 3-2 4.13 58.65 47.34 16.97 0.353 0.619 Example 4-1 4.17 67.49 50.89 19.60 0.352 0.618 Example 4-2 4.07 67.62 52.22 19.66 0.353 0.618 Comparative Example 4-1 4.82 56.66 36.91 16.37 0.345 0.623

The results of Table 4 are similar to the results of Table 2 above, and it can be confirmed that the performance of the organic light emitting diode according to the present invention is remarkably improved.

1: Substrate 2: Anode
3: first hole accelerating layer 4: first hole transport layer
5: second hole accelerating layer 6: second hole transport layer
7: light emitting layer 8: electron transport layer
9: Cathode

Claims (13)

anode,
a first hole accelerating layer comprising a first host and a first dopant;
a first hole transport layer;
a second hole accelerating layer comprising a second host and a second dopant;
a second hole transport layer;
light emitting layer,
an electron transport layer, and
In the organic light emitting device comprising a cathode,
The first dopant and the second dopant are the same material as each other,
The second host is a compound represented by the following formula (1),
The second hole transport layer comprises the second host,
Organic light emitting device:
[Formula 1]

In Formula 1,
each R is independently substituted or unsubstituted C _1-60 alkyl, or substituted or unsubstituted C _6-60 aryl;
L ₁ and L ₂ are each independently a single bond; Or a substituted or unsubstituted C _6-60 arylene,
Ar ₁ is a substituted or unsubstituted C _6-60 aryl,
Ar ₂ is substituted or unsubstituted C _6-60 aryl; or substituted or unsubstituted adamantyl.
According to claim 1,
In the first hole accelerating layer, the weight ratio of the first host and the first dopant is 90:10 to 99:1,
organic light emitting device.
According to claim 1,
In the second hole accelerating layer, the weight ratio of the second host to the second dopant is 90:10 to 99:1,
organic light emitting device.
According to claim 1,
R is all methyl or all phenyl;
organic light emitting device.
According to claim 1,
L ₁ is each independently, a single bond, or phenylene,
organic light emitting device.
According to claim 1,
L ₂ are each independently a single bond, phenylene, biphenyldiyl, or terphenyldiyl,
organic light emitting device.
According to claim 1,
Ar ₁ is phenyl, biphenylyl, terphenylyl, naphthyl, phenanthrenyl, dimethylfluorenyl, or diphenylfluorenyl;
organic light emitting device.
According to claim 1,
Ar ₂ is substituted or unsubstituted spirobifluorenyl; substituted or unsubstituted dimethylfluorenyl; substituted or unsubstituted diphenylfluorenyl; substituted or unsubstituted triphenylenyl; Or substituted or unsubstituted adamantyl,
organic light emitting device.
According to claim 1,
Ar ₂ is any one selected from the group consisting of
Organic light emitting device:

.
According to claim 1,
The compound represented by Formula 1 is any one selected from the group consisting of
Organic light emitting device:

.
According to claim 1,
The first host is a compound of
Organic light emitting device:

.
According to claim 1,
The first dopant is a compound of
Organic light emitting device:

.
According to claim 1,
The difference between the band gap of the first host and the second host is 0.3 eV or less,
organic light emitting device.

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