KR20200142492A - Light emitting device comprising the same - Google Patents

Abstract

The present invention provides an organic light emitting device with a low driving voltage, high luminous efficiency, and excellent lifespan. The organic light emitting device comprises: a positive electrode; a negative electrode; a light emitting layer between the positive electrode and the negative electrode; and an electron injection layer between the positive electrode and the light emitting layer.

Description

Organic light emitting device {Light emitting device comprising the same}

The present invention relates to an organic light-emitting device having a low driving voltage, high luminous efficiency, and excellent lifespan.

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

The 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 material layer is often made of a multi-layered structure composed of different materials in order to increase the efficiency and stability of the organic light emitting device.For example, it may be formed of 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 such an organic light-emitting device, when a voltage is applied between the two electrodes, holes are injected from the anode and electrons from the cathode are injected into the organic material layer, and excitons are formed when the injected holes and electrons meet. It glows when it falls back to the ground.

Development of new materials for organic materials used in organic light emitting devices as described above is continuously required.

Korean Patent Publication No. 10-2000-0051826

The present invention relates to an organic light-emitting device having a low driving voltage, high luminous efficiency, and excellent lifespan.

In order to solve the above problems, the present invention provides the following organic light emitting device.

anode,

cathode,

A light emitting layer between the anode and the cathode, and

Including an electron injection layer between the cathode and the light emitting layer,

The electron injection layer comprises a compound represented by the following Formula 1 or Formula 2,

Organic light emitting element:

[Formula 1]

In Formula 1,

*(1) and *(2) are each connected to any one of the following (1)* and (2)*,

Each Y is independently O or S,

Each R ₁ is independently -XM,

Each R ₂ is independently hydrogen or -XM,

Each X is independently O or S,

M is each independently an alkali metal or an alkaline earth metal,

[Formula 2]

In Chemical Formula 2,

Z is O, or S,

A is substituted or unsubstituted naphthalene, phenanthrene, fluoranthene, or terphenyl,

Ar ₁ and Ar ₂ are each independently substituted or unsubstituted C _1-20 alkyl; Or substituted or unsubstituted C _6-60 aryl; Or C _2-60 heteroaryl including any one or more heteroatoms selected from the group consisting of substituted or unsubstituted N, O and S; Or Ar ₁ and Ar ₂ may be combined to form a ring,

R ₃ is -XM,

X is O or S,

M is an alkali metal or alkaline earth metal.

The compound represented by Formula 1 or 2 described above may be used as a material for an electron injection layer of an organic light-emitting device, and may improve efficiency, low driving voltage, and/or lifetime characteristics in the organic light-emitting device.

1 shows an example of an organic light-emitting device comprising a substrate 1, an anode 2, a light-emitting layer 3, an electron injection layer 4, and a cathode 5.
FIG. 2 is composed of a substrate (1), an anode (2), a hole injection layer (6), a hole transport layer (7), a light emitting layer (3), an electron transport layer (8), an electron injection layer (4) and a cathode (5). An example of an organic light emitting device is shown.

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

는 다른 치환기에 연결되는 결합을 의미한다. In this specification,

Means a bond connected to another substituent.

In the present specification, the term "substituted or unsubstituted" refers to deuterium; Halogen group; Nitrile group; Nitro group; Hydroxy group; Carbonyl group; Ester group; Imide group; Amino group; Phosphine oxide group; Alkoxy group; Aryloxy group; Alkyl thioxy group; Arylthioxy group; Alkyl sulfoxy group; Arylsulfoxy group; Silyl group; Boron group; Alkyl group; Cycloalkyl group; Alkenyl group; Aryl group; Aralkyl group; Aralkenyl group; Alkylaryl group; Alkylamine group; Aralkylamine group; Heteroarylamine group; Arylamine group; Arylphosphine group; Or it means a substituted or unsubstituted substituted or unsubstituted with one or more substituents selected from the group consisting of a heterocyclic group containing one or more of N, O and S atoms, or linked with two or more substituents among the above-exemplified substituents. . For example, "a substituent to which two or more substituents are connected" may be a biphenyl group. That is, the biphenyl group may be an aryl group or may be interpreted as a substituent to which two phenyl groups are connected.

* In the present specification, the number of carbon atoms of the carbonyl group is not particularly limited, but it is 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, the ester group may be substituted with an oxygen of the ester group with a straight chain, 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 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 is specifically trimethylsilyl group, triethylsilyl group, t-butyldimethylsilyl group, vinyldimethylsilyl group, propyldimethylsilyl group, triphenylsilyl group, diphenylsilyl group, phenylsilyl group, etc. However, it is not limited thereto.

In the present specification, the boron group specifically includes a trimethyl boron group, a triethyl boron group, a t-butyldimethyl boron group, a triphenyl boron group, and a phenyl boron group, but is not limited thereto.

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

In the present specification, the alkyl group may be a linear or branched chain, and the number of carbon atoms is not particularly limited, but is preferably 1 to 40. According to an exemplary embodiment, the alkyl group has 1 to 20 carbon atoms. 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, cycloheptylmethyl, 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 a linear or branched chain, and the number of carbon atoms is not particularly limited, but is preferably 2 to 40. According to an exemplary embodiment, the alkenyl group has 2 to 20 carbon atoms. According to another exemplary embodiment, the alkenyl group has 2 to 10 carbon atoms. 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 is preferably 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 cycloalkyl group has 3 to 20 carbon atoms. 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 are not limited thereto.

In the present specification, the aryl group is not particularly limited, but is preferably 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to an exemplary embodiment, the aryl group has 6 to 30 carbon atoms. According to an exemplary embodiment, the aryl group has 6 to 20 carbon atoms. The aryl group may be a phenyl group, a biphenyl group, or a terphenyl group, but the monocyclic aryl group 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. However, it 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 carbons is not particularly limited, but it is preferably 2 to 60 carbon atoms. Examples of the heterocyclic group include thiophene group, furan group, pyrrole group, imidazole group, thiazole group, oxazole group, oxadiazole group, triazole group, pyridyl group, bipyridyl group, pyrimidyl group, triazine 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, benzoxazole group, benzoimidazole group, benzothiazole group, benzocarbazole group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, isoxazolyl group, thiiadia There may be a zolyl group, a phenothiazinyl group, and a dibenzofuranyl group, but are not limited thereto.

In the present specification, the aryl group among the aralkyl group, aralkenyl group, alkylaryl group, and 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 aforementioned alkyl group. In the present specification, for heteroaryl among heteroarylamines, the description of the aforementioned heterocyclic group may be applied. In the present specification, the alkenyl group of the aralkenyl group is the same as the example of the alkenyl group described above. In the present specification, the description of the aryl group described above may be applied except that the arylene is a divalent group. In the present specification, the description of the aforementioned heterocyclic group may be applied except that the heteroarylene is a divalent group. In the present specification, the hydrocarbon ring is not a monovalent group, and the description of the aryl group or the cycloalkyl group described above may be applied except that the hydrocarbon ring is formed by bonding of two substituents. In the present specification, the heterocycle is not a monovalent group, and the description of the aforementioned heterocyclic group may be applied, except that two substituents are bonded to each other.

Anode and cathode

As the anode material, a material having a large work function is preferable so that holes can be smoothly injected into the organic material layer. Specific examples of the cathode material 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); A combination of a metal and an oxide such as ZnO:Al or SNO ₂ :Sb; Poly(3-methylthiophene), poly[3,4-(ethylene-1,2-dioxy)thiophene] (PEDOT), conductive polymers such as polypyrrole and polyaniline, and the like, but are not limited thereto.

It is preferable that the cathode material is 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; There are multi-layered materials such as LiF/Al or LiO ₂ /Al, but are not limited thereto.

In addition, a hole injection layer may be additionally included on the anode. The hole injection layer is made of a hole injection material, and the hole injection material has the ability to transport holes, and thus has a hole injection effect at the anode, an excellent hole injection effect for the light emitting layer or the light emitting material. A compound that prevents migration to the electron injection layer or the electron injection material and has excellent thin film formation ability is preferable.

It is preferable that the HOMO (highest occupied molecular orbital) of the hole injection material is between the work function of the positive electrode material and the HOMO of the surrounding organic material layer. Specific examples of the hole injection material include metal porphyrin, oligothiophene, arylamine-based organic material, hexanitrile hexaazatriphenylene-based organic material, quinacridone-based organic material, perylene There are a series of organic substances, anthraquinone, and polyaniline and a polythiophene series of conductive polymers, but are not limited thereto.

Hole transport layer

The hole transport layer used in the present invention is a layer that receives holes from the anode or the hole injection layer formed on the anode and transports holes to the emission layer, and can be transferred to the emission layer by transporting holes from the anode or the hole injection layer as a hole transport material. A material with high mobility for holes is suitable.

Specific examples include an arylamine-based organic material, a conductive polymer, and a block copolymer including a conjugated portion and a non-conjugated portion, but are not limited thereto.

Emitting layer

The light-emitting material included in the light-emitting layer is a material capable of emitting light in the visible light region by transporting and combining holes and electrons from the hole transport layer and the electron transport layer, and a material having good quantum efficiency for fluorescence or phosphorescence is preferable. Specific examples of 8-hydroxy-quinoline aluminum complex (Alq ₃ ); Carbazole-based compounds; Dimerized styryl compounds; BAlq; 10-hydroxybenzo quinoline-metal compound; Benzoxazole, benzthiazole, and benzimidazole-based compounds; Poly(p-phenylenevinylene) (PPV)-based polymer; Spiro compounds; Polyfluorene, rubrene, and the like, but are not limited thereto.

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

Dopant materials include aromatic amine derivatives, strylamine compounds, boron complexes, fluoranthene compounds, and metal complexes. 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 substituted or unsubstituted As a compound in which at least one arylvinyl group is substituted on the arylamine, one or two or more substituents selected from the group consisting of an aryl group, silyl group, alkyl group, cycloalkyl group, and arylamino group are substituted or unsubstituted. Specifically, there are styrylamine, styryldiamine, styryltriamine, styryltetraamine, and the like, but are not limited thereto. In addition, the metal complex includes an iridium complex, a platinum complex, and the like, but is not limited thereto.

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 electron injection layer. The electron transport layer is a layer that receives electrons from the electron injection layer and transports electrons to the emission layer. As an electron transport material, a material capable of injecting electrons from the cathode and transferring them to the emission layer, and a material having high mobility for electrons is suitable. Do. Specific examples include 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 can be used with any desired cathode material as used according to the prior art. In particular, examples of suitable cathode materials are conventional materials that have a low work function and are followed by an aluminum layer or a silver layer. Specifically, they are cesium, barium, calcium, ytterbium, and samarium, and in each case an aluminum layer or a silver layer follows.

Electron injection layer

The electron injection layer is a layer that injects electrons from an electrode, has the ability to transport electrons, has an electron injection effect from the cathode, an excellent electron injection effect for a light emitting layer or a light emitting material, and a compound having excellent thin film formation ability desirable. In addition, the electron injection layer may also serve as the aforementioned electron transport layer.

In particular, in the present invention, the compound represented by Formula 1 or Formula 2 is used as a material for the electron injection layer.

Preferably, M is Li.

Preferably, Formula 2 is any one selected from the group consisting of:

In the above, Z, Ar ₁ , Ar ₂ and R ₃ are as defined above.

Preferably, Ar ₁ and Ar ₂ are each independently methyl, ethyl, phenyl, tolyl, biphenylyl, naphthyl, pyridinyl, quinolinyl, or isoquinolinyl. More preferably, Ar ₁ and Ar ₂ are phenyl.

Preferably, the compound represented by Formula 1 or Formula 2 is any one selected from the group consisting of:

In addition, the present invention provides a method for preparing a compound represented by Chemical Formula 1 as shown in Scheme 1 below, and can be applied to the rest of the compounds.

[Scheme 1]

In Reaction Scheme 1, the rest except for R'are as previously defined, and R'is -OH, or -SH.

In addition, the present invention provides a method of preparing a compound represented by Chemical Formula 2 as shown in Scheme 2 below.

[Scheme 2]

In Reaction Scheme 2, the rest except for R'are as defined above, and R'is -OH or -SH.

Reaction Schemes 1 and 2 are reactions of reacting each starting material with an organolithium agent. The organolithium compound that can be used in the reaction may be appropriately selected according to the compound to be prepared, and n-butyl lithium may be used as an example. The manufacturing method may be more specific in the manufacturing examples to be described later.

In addition, the electron injection layer may simultaneously serve as an electron transport layer and an electron injection layer. In this case, the material of the electron transport layer may be mixed with the material of the electron injection layer, and the weight ratio of each material may be used in the range of 1:10 to 10:1.

Organic light emitting element

The structure of the organic light emitting device according to the present invention is illustrated in FIG. 1. 1 shows an example of an organic light-emitting device comprising a substrate 1, an anode 2, a light-emitting layer 3, an electron injection layer 4, and a cathode 5. In such a structure, the compound represented by Formula 1 or 2 may be included in the electron injection layer.

FIG. 2 is composed of a substrate (1), an anode (2), a hole injection layer (6), a hole transport layer (7), a light emitting layer (3), an electron transport layer (8), an electron injection layer (4) and a cathode (5). An example of an organic light emitting device is shown. In such a structure, the compound represented by Formula 1 or 2 may be included in the electron injection layer.

The organic light emitting device according to the present invention can be manufactured by sequentially stacking the above-described configurations. At this time, using a PVD (physical vapor deposition) method such as sputtering or e-beam evaporation, the anode is formed by depositing a metal or a conductive metal oxide or an alloy thereof on the substrate. And, after forming each of the above-described layers thereon, it can be prepared by depositing a material that can be used as a cathode thereon. In addition to this method, an organic light-emitting device may be manufactured by sequentially depositing a cathode material, an organic material layer, and an anode material on a substrate. In addition, the light emitting layer may be formed by a solution coating method as well as a vacuum deposition method of a host and a dopant. Here, the solution coating 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.

In addition to such a method, an organic light-emitting device may be manufactured by sequentially depositing an organic material layer and an anode material from a cathode material on a substrate (WO 2003/012890). However, the manufacturing method is not limited thereto.

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

Fabrication of the organic light emitting device according to the present invention will be described in detail in the following examples. However, the following examples are for illustrating the present invention, and the scope of the present invention is not limited thereto.

[Example]

Example 1: Preparation of compound 1

Under a nitrogen stream, 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (8 g, 57.1 mmol) was added to 0.7 M anhydrous THF solvent and then cooled to -78°C. . When the temperature was reached, a solution of n-butyl lithium (2.5 M in hexane) was added over 30 minutes and then slowly raised to room temperature and stirred for 3 hours and 30 minutes. After completion of the reaction, the solvent was distilled to solidify and then purified with ethanol to prepare compound 1 (5.4 g, yield 62%).

MS: [M+H] ⁺ = 153

Example 2: Preparation of compound 2

What used 2,3,5,6-tetrahydroxycyclohexa-2,5-diene-1,4-dione instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione Except, compound 2 was prepared by the same method as the method of preparing compound 1.

MS: [M+H] ⁺ = 197

Example 3: Preparation of compound 3

Method for preparing compound 1, except that (3-hydroxynaphthalen-2-yl) diphenylphosphine oxide was used instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione Compound 3 was prepared in the same manner as described above.

MS: [M+H] ⁺ = 351

Example 4: Preparation of compound 4

Instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (4'-hydroxy-[1,1':3',1''-terphenyl]-5'-yl ) Except for the use of diphenylphosphine oxide, compound 4 was prepared in the same manner as in the preparation method of compound 1.

MS: [M+H] ⁺ = 453

Example 5: Preparation of compound 5

Compounds except that 2-hydroxy-10,10a-dihydrophenanthrene-3(9H)-thione was used instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione Compound 5 was prepared in the same manner as in Preparation Method 1.

MS: [M+H] ⁺ = 235

Example 6: Preparation of compound 6

Except for using 3-hydroxyanthracene-2(4aH)-thione instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione, in the same manner as in the preparation of compound 1 Compound 6 was prepared.

MS: [M+H] ⁺ = 233

Example 7: Preparation of compound 7

Except for using 2-hydroxynaphthalene-1(8aH)-one instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione, in the same manner as in the preparation of compound 1 Compound 7 was prepared.

MS: [M+H] ⁺ = 167

Example 8: Preparation of compound 8

Except that (1-hydroxyfluoranthen-2-yl) diphenylphosphine oxide was used instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione, Compound 8 was prepared in the same manner as in the preparation method.

MS: [M+H] ⁺ = 425

Example 9: Preparation of compound 9

In place of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione (10-hydroxyphenanthrene-9-yl) (methyl) (pyridin-2-yl) phosphine oxide Except, compound 9 was prepared by the same method as the method of preparing compound 1.

MS: [M+H]+ = 340

Example 10: Preparation of compound 10

Except for using 5-(3-mercaptonaphthalen-2-yl)benzo[b]phosphindol 5-oxide instead of 2,5-dihydroxycyclohexa-2,5-diene-1,4-dione , Compound 10 was prepared in the same manner as in the preparation method of compound 1.

MS: [M+H] ⁺ = 365

[Experimental Example]

Experimental Example 1

A glass substrate (corning 7059 glass) coated with a thin film of ITO (indium tin oxide) having a thickness of 1000 Å was placed in distilled water in which a dispersant was dissolved and washed with ultrasonic waves. The detergent was manufactured by Fischer Co., and the distilled water was Millipore Co. Distilled water filtered secondarily with the product's filter was used. After washing the ITO for 30 minutes, ultrasonic washing was performed for 10 minutes by repeating twice with distilled water. After washing with distilled water, ultrasonic washing was performed in the order of isopropyl alcohol, acetone, and methanol, followed by drying.

The HAT-CN compound was thermally vacuum deposited to a thickness of 500Å on the prepared ITO transparent electrode to form a hole injection layer. On the hole injection layer, the following HT1 compound was vacuum-deposited to a thickness of 400 Å to form a hole transport layer. On the hole transport layer, the following BH1 compound and the following BD1 compound were vacuum-deposited to a thickness of 300Å at a weight ratio of 95:5 to form a light emitting layer. On the light emitting layer, the following Compound ET-A and Compound 1 prepared in Example were vacuum-deposited at a weight ratio of 1:1 to form an electron injection layer with a thickness of 350Å. An organic light-emitting device was manufactured by sequentially depositing lithium fluoride (LiF) with a thickness of 12 Å and aluminum with a thickness of 2,000 Å on the electron injection layer to form a cathode.

In the above process, the deposition rate of organic material was maintained at 0.4 ~ 0.7 Å/sec, the deposition rate of lithium fluoride at the negative electrode was 0.3 Å/sec, and the deposition rate of aluminum was 2 Å/sec, and the vacuum degree during deposition was 2×10. ^-7 ~ 5 × 10 ^-6 torr was maintained.

Experimental Examples 2 to 10

It was prepared in the same manner as in Experimental Example 1, but an organic light-emitting device was manufactured using the compound shown in Table 1 instead of Compound 1.

Comparative Experimental Examples 1 to 3

It was prepared in the same manner as in Experimental Example 1, but an organic light-emitting device was manufactured using the compound shown in Table 1 instead of Compound 1. In Table 1 below, compounds LiQ, EIL A, and EIL B are as follows.

For the organic light-emitting device prepared in the above Experimental Examples and Comparative Experimental Examples, the driving voltage, luminous efficiency and color coordinates were measured at a current density of 10 mA/cm ² , and 90% of the initial luminance at a current density of 20 mA/cm ² The time to become (T90) was measured. The results are shown in Table 1 below.

compound Voltage
(V) efficiency
(cd/A) Color coordinates
(x, y) Life (T90)
(hr) Experimental Example 1 Compound 1 3.76 5.64 (0.134, 0.126) 122 Experimental Example 2 Compound 2 3.86 5.81 (0.134, 0.125) 124 Experimental Example 3 Compound 3 3.79 5.79 (0.134, 0.125) 132 Experimental Example 4 Compound 4 3.88 5.66 (0.134, 0.126) 119 Experimental Example 5 Compound 5 3.83 5.70 (0.134, 0.126) 120 Experimental Example 6 Compound 6 3.87 5.59 (0.134, 0.126) 125 Experimental Example 7 Compound 7 3.73 5.60 (0.134, 0.125) 128 Experimental Example 8 Compound 8 3.86 5.64 (0.134, 0.126) 123 Experimental Example 9 Compound 9 3.72 5.77 (0.134, 0.125) 121 Experimental Example 10 Compound 10 3.81 5.73 (0.134, 0.126) 130 Comparative Experimental Example 1 LiQ 4.65 4.47 (0.134, 0.127) 92 Comparative Experiment 2 EIL A 4.58 4.54 (0.134, 0.126) 87 Comparative Experiment 3 EIL B 4.61 4.33 (0.134, 0.127) 84

As shown in Table 1, as a result of using the compound according to the present invention instead of LiQ for the electron injection layer, it was confirmed that electron injection from the cathode to the electron injection layer was efficiently performed, resulting in a reduction in driving voltage and high efficiency characteristics.

1: substrate 2: anode
3: light emitting layer 4: electron injection layer
5: cathode 6: hole injection layer
7: hole transport layer 8: electron transport layer
9: electron injection layer

Claims (5)

anode,
cathode,
A light emitting layer between the anode and the cathode, and
Including an electron injection layer between the cathode and the light emitting layer,
The electron injection layer comprises a compound represented by the following formula (2),
Organic light emitting element:
[Formula 2]

In Chemical Formula 2,
Z is O, or S,
A is a substituted or unsubstituted naphthalene,
Ar ₁ and Ar ₂ are each independently substituted or unsubstituted C _1-20 alkyl; Or substituted or unsubstituted C _6-60 aryl; Or C _2-60 heteroaryl including any one or more heteroatoms selected from the group consisting of substituted or unsubstituted N, O and S; Or Ar ₁ and Ar ₂ may be combined to form a ring,
R ₃ is -XM,
X is O, or S,
M is an alkali metal or alkaline earth metal.
The method of claim 1,
M is Li,
Organic light emitting device.
The method of claim 1,
Formula 2 is any one selected from the group consisting of,
compound:

In the above, Z, Ar ₁ , Ar ₂ and R ₃ are as defined in claim 1.
The method of claim 1,
Ar ₁ and Ar ₂ are each independently methyl, ethyl, phenyl, tolyl, biphenylyl, naphthyl, pyridinyl, quinolinyl, or isoquinolinyl,
Organic light emitting device.
The method of claim 1,
The compound represented by Formula 2 is any one selected from the group consisting of,
Organic light emitting element:

.

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