KR20150064863A - Organic Light Emitting Device and Display Apparatus Comprising The Same - Google Patents

Abstract

The present invention discloses an organic light emitting device and a display device comprising the same, which has improved charge injection efficiency and can operate at relatively lower voltage. The organic light emitting device includes a first electrode, a second electrode, and organic medium between the first and the second electrode and the organic medium includes material with charge mobility characteristics within molecules.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device and a display device including the organic light emitting device, and more particularly, to a display device having an improved charge injection efficiency and a relatively lower voltage by including a material having intramolecular charge transfer characteristics And a display device including the organic light emitting element.

The organic light emitting device includes an anode electrode, a cathode electrode, and an organic medium therebetween, and light is emitted while electrons and holes are coupled in the organic medium.

Various structures of the organic medium, for example, HTL / ETL, HTL / EML / ETL, HIL / HTL / EML / ETL / EIL structures have been proposed for improving the performance of the organic light emitting device. Herein, HIL is a hole injection layer, HTL is a hole transfer layer, EML is an emissive layer, ETL is an electron transfer layer, and EIL is an electron injection layer (Electron Injection Layer).

As the material of the hole injection layer, DNTPD, CuPc, or HAT-CN having the following structural formulas are generally used.

When a hole injection layer is formed using such a material, hole injection is difficult due to a difference in HOMO (Highest Occupied Molecular Orbital) energy level between the hole injection layer and the hole transport layer, .

Meanwhile, in order to further improve the performance of the organic light emitting device, a stacked organic light emitting device manufactured by stacking a plurality of unit devices has been proposed. Such a laminated organic light emitting device generally includes an intermediate connector disposed between the unit elements to supply positive and negative charges to each unit element, respectively.

It has been proposed to use an In-Zn-O (IZO) film, an In-Sn-O (ITO) film, a V ₂ O ₅ film or the like as the intermediate connection portion. However, when the IZO film and the ITO film are used as the intermediate connection portions, the lateral conductivity is high and the pixel crosstalk problem arises. Moreover, IZO films and ITO films require a sputtering process, which can cause damage to the underlying organic layer (s). The use of a V ₂ O ₅ film can limit the pixel crosstalk, but V ₂ O ₅ has a problem that it has a very strong toxicity and is difficult to heat evaporate.

As another constitution for the intermediate connection, a doped organic p-n junction effective in terms of ease of manufacture has been proposed. Specifically, the intermediate connection portion formed using the doped organic p-n junction includes a p-type charge generation layer for generating holes and an n-type charge generation layer for generating electrons. The p-type charge generation layer is formed of a hole transport material doped with an electron acceptor (i.e., p-dopant), and the n-type charge generation layer is formed of a metal doped electron Transporting material.

When an electric field is applied between two electrodes of the organic light emitting device, electrons move from the HOMO of the host material having the hole transporting property of the p-type charge generating layer to the LUMO (Lowest Occupied Molecular Orbital) of the p-dopant, The p-dopant molecule becomes an anion to pass the electrons to the neighboring n-type charge generation layer, and the neutral host molecule becomes the cation to pass holes to the neighboring thin film (mainly the hole transport layer).

In order for the p-type charge generating layer to perform its role well, the energy level difference between the HOMO of the host material and the LUMO of the p-dopant material should be small. That is, since the hole transporting material conventionally used as the host material of the p-type charge generation layer has a HOMO of -5.0 eV or less, it is preferable that the p-dopant material also has a LUMO level of about -5.0 eV. However, it is not easy to realize an organic compound having a low LUMO level of about -5.0 eV, so there is a molecular structural limitation in selecting a material usable as a p-dopant.

Due to these limitations, it has been proposed to form a p-type charge generation layer using a material for the hollow injection layer, for example, HAT-CN. However, as described above, since the HOMO level of the material for the hole injection layer and the HOMO level of the material for the hole transport layer (in contact with the p-type charge generation layer) are significant, hole injection into the hole transport layer There is a problem that the driving voltage of the organic light emitting element rises.

Accordingly, the present invention is directed to an organic light emitting device and a display device including the organic light emitting device, which can prevent problems due to limitations and disadvantages of the related art.

One aspect of the present invention is to provide an organic light emitting device having an improved charge injection efficiency and being driven at a relatively lower voltage by including a substance having an intramolecular charge transfer property.

Another aspect of the present invention is to provide a display device including an organic light emitting device having an improved charge injection efficiency and being driven at a relatively lower voltage by including a substance having an intramolecular charge transfer property.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

According to an aspect of the present invention, there is provided a plasma display panel comprising: a first electrode; A second electrode; And an organic medium between the first and second electrodes, wherein the organic medium comprises a compound represented by the following Formula 1:

≪ Formula 1 >

Wherein R ₁ and R ₂ are selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted hetero And n is an integer of 1 to 5, and Ar is a substituted or unsubstituted C ₅ -C ₃₀ alkyl group, Or a fused heterocycle or a fused heterocycle having 5 to 30 nuclear atoms and R ₃ is hydrogen, deuterium, halogen, cyano, trifluoro, Selected from the group consisting of a methyl group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, and the following functional groups:

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According to another aspect of the present invention, there is provided a liquid crystal display comprising: a TFT substrate including a thin film transistor; An organic light emitting diode formed on the TFT substrate; And an encapsulation structure formed on the substrate and the organic light emitting device to cover the organic light emitting device, wherein the organic light emitting device comprises: a first electrode; A second electrode; And an organic medium between the first and second electrodes, wherein the organic medium comprises a compound represented by the following Formula 1:

≪ Formula 1 >

Wherein R ₁ and R ₂ are selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted hetero And n is an integer of 1 to 5, and Ar is a substituted or unsubstituted C ₅ -C ₃₀ alkyl group, Or a fused heterocycle or a fused heterocycle having 5 to 30 nuclear atoms and R ₃ is hydrogen, deuterium, halogen, cyano, trifluoro, Selected from the group consisting of a methyl group, a nitro group, a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, and the following functional groups:

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The foregoing general description of the present invention is intended to be illustrative of or explaining the present invention, but does not limit the scope of the present invention.

According to the present invention, the organic medium, particularly the hole injection layer and / or the p-type charge generation layer, contains a substance having an intramolecular charge transfer property, and thus has an improved charge injection efficiency and is driven with a relatively lower voltage And a display device including the organic light emitting element can be realized.

As a result, the power consumption of the display device employing the organic light emitting element of the present invention can be lowered.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 schematically shows a cross-section of a display device according to an embodiment of the present invention,
2 schematically shows a cross-section of a TFT substrate according to an embodiment of the present invention,
3 schematically shows a cross-section of a TFT substrate according to another embodiment of the present invention,
Figure 4 shows the UV / visible light absorption spectra of ICT-1 compounds,
5 is a schematic cross-sectional view of an organic light emitting diode according to an embodiment of the present invention,
6 is a schematic cross-sectional view of an organic light emitting device according to another embodiment of the present invention,
7 is a schematic cross-sectional view of a first organic light emitting unit according to an embodiment of the present invention,
8 is a schematic cross-sectional view of an Nth organic light emitting unit according to an embodiment of the present invention,
9 schematically shows a cross section of an organic light emitting unit according to an embodiment of the present invention disposed between two organic light emitting units,
10 schematically shows a cross-section of an intermediate connection according to an embodiment of the present invention.

Hereinafter, embodiments of an organic light emitting diode and a display device including the organic light emitting diode according to the present invention will be described in detail with reference to the accompanying drawings.

In describing an embodiment of the present invention, when a structure is described as being "on" (or placed on) another structure, such a substrate is not limited to the case where these structures are in contact with each other, It should be construed to include the case where the third structure is interposed. However, if the term "directly on" is used, these structures should be construed as limited to being in contact with each other.

The term " intramolecular charge transfer property "as used herein means a property capable of separating positive charge and negative charge within a molecule.

1 schematically shows a cross section of a display device according to an embodiment of the present invention.

The display device of the present invention includes a TFT substrate 100 including a thin film transistor, an organic light emitting device 200 on the TFT substrate 100, and the TFT substrate 100 to cover the organic light emitting device 200, And an encapsulation structure 300 formed on the organic light emitting device 200.

2 schematically shows a cross section of a TFT substrate 100 according to an embodiment of the present invention.

2, a TFT substrate 100 according to an embodiment of the present invention includes a substrate 110, and a thin film transistor T on the substrate 110.

The substrate 110 may be a glass substrate or a flexible substrate. The flexible substrate may include a polyimide film, a buffer layer on which the thin film transistor is formed on one side of the polyimide film, and a rear plate on the other side of the polyimide film.

The thin film transistor T includes a semiconductor layer 120, a gate electrode 140, and source / drain electrodes 170 and 160.

A gate insulating layer 130 is interposed between the semiconductor layer 120 and the gate electrode 140. An interlayer insulating layer 150 is disposed between the gate electrode 140 and the source / drain electrodes 170 and 160.

An overcoat layer 180 is disposed on the interlayer insulating layer 150 and the source / drain electrodes 170 and 160 to protect the TFT and flatten the step due to the TFT.

The first electrode 210 of the organic light emitting diode 200 is electrically connected to the drain electrode 160 of the thin film transistor T through a hole formed in the overcoat layer 180.

The TFT substrate 100 illustrated in FIG. 2 includes a top-gate type thin film transistor T in which a gate electrode 140 is disposed on the semiconductor layer 120. However, But may also include a bottom-gate type thin film transistor in which the gate electrode is located below the semiconductor layer.

3, a TFT substrate 100 'according to another embodiment of the present invention includes a substrate 111 formed of a glass or plastic material, a gate electrode 112 on the substrate 111, A gate insulating film 113 on the substrate 111 and the gate electrode 112, a semiconductor layer 114 formed to overlap the gate electrode 112 with the gate insulating film 113 therebetween, the gate insulating film 113 Source and drain electrodes 116 and 115 formed on the semiconductor layer 114 and an inorganic insulating layer 117 and an organic insulating layer 118 sequentially formed on a substrate 111 on which a thin film transistor T is formed, . The first electrode 210 of the organic light emitting diode 200 is electrically connected to the drain electrode 115 of the thin film transistor T through a hole formed in the inorganic insulating film 117 and the organic insulating film 118. [ do.

1, a display device according to an exemplary embodiment of the present invention includes a TFT substrate 100 and an encapsulation structure (not shown) formed on the organic light emitting device 200 such that the organic light emitting device 200 is covered 300). The encapsulation structure 300 prevents moisture or oxygen from penetrating into the organic medium of the organic light emitting device 200, and thus it is preferable that the encapsulation structure 300 completely covers the entire organic light emitting device 200.

The encapsulation structure 300 may be formed by forming a protective layer on the organic light emitting device 200 and then forming a sealing film including an inorganic film and an organic film on the organic light emitting device 200 using an adhesive or double- (Encapsulation Film Type) formed by adhering the inorganic thin film and the organic thin film on the TFT film 100 having the organic light emitting device 200 or by alternately laminating the inorganic thin film and the organic thin film on the TFT film 100 on which the organic light emitting device 200 is formed (Thin Film Encapsulation), but the present invention is not limited to such encapsulation structure types.

The display device according to an embodiment of the present invention further includes a circular polarizer 400 on the encapsulation structure 300 and a front module 500 on the circular polarizer 400 as illustrated in FIG. .

The circular polarizer 400 prevents external light reflected by the organic light emitting device 200 from being deteriorated in visibility caused by emission of the external light from the display device, .

The circular polarizer 400 may include a λ / 4 retardation film 410 on the encapsulation structure 300 and a linear polarizer film 420 on the λ / 4 retardation film 410. The external light passes through the linear polarization film 420 and becomes linearly polarized light. The linearly polarized light passes through the? / 4 retardation film 410 and is reflected by the organic light emitting device 200 and is reflected by the? / 4 retardation film 410 The light is converted into linearly polarized light perpendicular to the transmission axis of the linear polarizing film 420, and is then absorbed by the linear polarizing film 420.

The front module 500 may include a touch film 510 and a cover window 520 and may be attached to the circular polarizer plate 510 through a pressure sensitive adhesive (PSA), an optically clear adhesive (OCA) (Not shown).

Hereinafter, the organic light emitting diode 200 on the TFT substrate 100 will be described in more detail with reference to FIGS. 4 to 10. FIG.

The organic light emitting diode 200 according to an exemplary embodiment of the present invention includes a first electrode 210, a second electrode 220, and an organic medium 230 between the first and second electrodes 210 and 220. [ . The organic light emitting device 200 is formed by sequentially laminating the first electrode 210, the organic medium 230, and the second electrode 220 on the TFT substrate 100.

According to the present invention, the organic medium 230 includes a compound having an intramolecular charge transfer property represented by the following formula (1).

≪ Formula 1 >

Wherein R ₁ and R ₂ are each independently selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, They may be combined to form a ring or not,

n is an integer of 1 to 5,

Ar is a substituted or unsubstituted C ₅ -C ₃₀ ring or condensed ring or a heterocyclic or condensed heterocyclic ring having 5 to 30 ring atoms,

R ₃ is selected from the group consisting of hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle Group, and the following functional groups.

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In one embodiment of the invention, substitution of the R ₁ and R ₂ are C ₁ -C ₄₀ substituted or unsubstituted alkyl group, C ₃ -C ₄₀ substituted or unsubstituted cycloalkyl group, C ₆ -C ₄₀ of Or an unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group having 5 to 30 nucleus atoms, and may be bonded to each other to form a ring or not.

According to an embodiment of the present invention, R ₃ is selected from the group consisting of hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, substituted or unsubstituted C ₁ -C ₄₀ alkyl, substituted C ₃ -C ₄₀ Or an unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group having _{6 to 40} carbon atoms, a substituted or unsubstituted heterocyclic group having 5 to 30 nuclear atoms, and the following functional groups.

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According to one embodiment of the present invention, Ar has a substituted or unsubstituted arylamine group as a substituent. Specifically, the compound may be a compound represented by any one of the following formulas.

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More specifically, the compound may be any one of the following ICT-1, ICT-2, ICT-3, ICT-4, and ICT-5.

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≪ Production method of ICT-1 >

5.0 g (= 8.5 mmol) of 4,4'-bis- (1-naphthyl-N-phenylamino) -biphenyl (NPD) and 1.3 g of tetracyanoethane (TCNE) were added to a 250 mL round bottom flask under nitrogen atmosphere = 10.2 mmol) was added with 120 mL of DMF and refluxed for 12 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure, and the residue was subjected to column chromatography (eluent: dichloromethane 100%) to give a compound of ICT-1. The reaction formula is as follows.

Fig. 4 shows the UV / visible light absorption spectrum of the ICT-1 compound thus obtained. As can be seen from Fig. 4, absorption (B) corresponding to the charge transfer transition occurred in addition to the absorption (A) corresponding to the transition of π-> π *. From these facts, it can be seen that the ICT- And the like.

<Production method of ICT-2>

5.0 g (= 6.3 mmol) of tris (N-3-methylphenyl-N-phenylamino) triphenylamine (m-MTDATA) and 1.0 g of tetracyanoethane (TCNE) were added to a 250 mL round bottom flask under nitrogen atmosphere ) Was added with 150 mL of DMF and refluxed for 16 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure, and the residue was subjected to column chromatography (eluent: dichloromethane 100%) to give a compound of ICT-2. The reaction formula is as follows.

<Production method of ICT-3>

5.0 g (= 8.6 mmol) of 1,3,5-tris (diphenylamino) benzene and 1.3 g (= 10.3 mmol) of tetracyanoethane (TCNE) were placed in a 250 mL round bottom flask under a nitrogen atmosphere, Lt; / RTI &gt; After cooling to room temperature, the mixture was concentrated under reduced pressure, and the residue was subjected to column chromatography (eluent: dichloromethane 100%) to obtain a compound of ICT-3. The reaction formula is as follows.

<Production method of ICT-4>

(N, N-diphenylamino) -9,9-spirobifluorene [2,2 ', 7,7'-Tetrakis (triphenylphosphine)] was added to a 250 mL round bottom flask under a nitrogen atmosphere. (N, N-diphenylamino) -9,9-spirobifluorene] and 1.2 g (= 9.2 mmol) of tetracyanoethane (TCNE) were added to 150 ml of DMF and refluxed for 16 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure, and the residue was subjected to column chromatography (eluent: dichloromethane / methanol 20: 1 v / v%) to give ICT-4. The reaction formula is as follows.

<Production method of ICT-5>

5.0 g (= 8.8 mmol) of di- [(N, N-diphenyl-amino) -phenyl] cyclohexane and 1.3 g (= 10.5 mmol) of tetracyanoethane (TCNE) were added to a 250 mL round bottom flask in a DMF And the mixture was refluxed for 12 hours. After cooling to room temperature, the mixture was concentrated under reduced pressure, and the residue was subjected to column chromatography (eluent: dichloromethane / n-hexane 3: 1 v / v%) to give ICT-5. The reaction formula is as follows.

Hereinafter, an organic light emitting diode 200 according to an embodiment of the present invention will be described in detail with reference to FIG.

5, an organic light emitting diode 200 according to an exemplary embodiment of the present invention includes a first electrode 210, a second electrode 220, and first and second electrodes 210 and 220 Wherein the organic medium 230 includes a hole injection layer 231 on the first electrode 210, a hole transport layer 232 on the hole injection layer 231, And a light emitting layer 233 on the hole transport layer 232.

The first electrode 210 is electrically connected to the thin film transistor T (more specifically, the drain electrode 160 or 115) of the TFT substrate 100. The first electrode 210 may have a high work function such as ITO (Indium Tin Oxide), IZO (Indium Tin Oxide), ITZO (Indium Tin Zinc Oxide), ICO May be formed of a conductive material.

The second electrode 220 may be formed of aluminum (Al), magnesium (Mg), calcium (Ca), silver (Ag), or an alloy thereof having a low work function as a cathode electrode.

The hole injection layer 231 improves film formation characteristics of the subsequent hole transport layer 232 and facilitates hole injection into the hole transport layer 232 to reduce the driving voltage of the OLED 200 .

The hole injection layer 231 according to an embodiment of the present invention includes a compound having an intramolecular charge transfer property represented by Formula 1. [

Alternatively, the hole injecting layer 231 may include the hole transporting material of the hole transporting layer 232 and the compound of the above formula (1). In this case, the content of the compound in the hole injection layer 231 may be 0.5 to 50% by weight.

When the compound contained in the hole injection layer 231 is the ICT-1, ICT-2, ICT-3, ICT-4 or ICT-5, the content of the compound in the hole injection layer 231 is 5 to 20% by weight.

According to one embodiment of the present invention, the HOMO energy level difference between the hole injection layer 231 and the hole transport layer 232 is reduced, so that hole injection into the hole transport layer 232 can be facilitated, As a result, the driving voltage of the organic light emitting diode 200 is lowered.

The hole transport layer 232 may be formed using one or more hole transport compounds such as aromatic tertiary amines. For example, the hole transport compound can be selected from the group consisting of 1,4-bis [2- [4- [N, N-di (p- tolyl) amino] phenyl] vinyl] benzene (BDTAPVB), 4,4'- - (1-naphthyl) -N- (2-naphthyl) amino] biphenyl (TNB) , 4,4 ', 4 "-tris [(3-methylphenyl) phenylamino] triphenylamine (MTDATA), 4,4'-bis [N- ), But the present invention is not limited thereto.

The light emitting layer 233 is a region where electrons and holes are recombined, and light is emitted as a result of recombination of electrons and holes. The light emitting layer 233 may be formed of a single material, but is typically formed by doping a host compound with an amount of about 0.01 to 10 wt% of a guest compound. Generally, the color of the light emitted from the light emitting layer 233 depends on the guest compound (i.e., dopant).

The host material may be formed of an electron transporting material, a hole transporting material, or a material capable of electron-hole recombination. For example, the host material may be a metal chelated oxinoid compound such as tris (8-hydroxyquinolinato) aluminum (Alq3), an anthracene derivative such as 9,10-di- (2-naphthyl) anthracene, Benzazole derivatives such as 2,2 ', 2 "- (1,3,5-phenylene) tris [1-phenyl-1H-benzimidazole], distyrylarylene derivatives, carbazole derivatives, However, the present invention is not limited thereto.

Examples of the dopant include an anthracene derivative, a tetracene derivative, a xanthene derivative, a perylene derivative, a rubrene derivative, a coumarin derivative, a rhodamine derivative, a quinacridone derivative, A phosphorescent dopant such as a dicyanomethylenepyran compound, a thiopyran compound, a polymethine compound, a pyrylium compound, or a phosphorescent dopant such as a transition metal complex can be used.

The organic light emitting device 200 according to an embodiment of the present invention further includes an electron transport layer 234 on the light emitting layer 233 and an electron injection layer 235 on the electron transport layer 234. [ However, when the host material of the light emitting layer 233 is a metal chelated oxinoid compound having excellent electron transporting ability such as tris (8-hydroxyquinolinato) aluminum (Alq3), the electron transport layer 234 and the electron The injection layer 235 may be omitted.

The electron transporting layer 234 may be formed of an electron transporting material alone or an electron transporting material doped with an n-dopant.

The electron transporting material may be a metal chelated oxinoid compound, butadiene derivative, benzazole, triazine, or the like having excellent electron transporting ability such as tris (8-hydroxyquinolinato) aluminum (Alq3) But is not limited thereto.

The n-dopant doped in the electron transporting material may be an alkali metal, an alkali metal compound, an alkaline earth metal, an alkaline earth metal compound or the like, but the present invention is not limited thereto. The alkali metal compound and the alkaline earth metal compound include an organometallic complex, a metal-organic salt, an inorganic salt, an oxide, and a halide. For example, the n-dopant may be lithium quinolate (Liq).

The electron injection layer 235 facilitates injection of electrons into the electron transport layer 234 and increases electrical conductivity to lower the driving voltage of the organic light emitting device 200. The electron injection layer 235 may be formed by doping the above-mentioned electron transporting material with a strong reducing agent or a metal having a low work function, or may be formed of a metal having a low work function or a salt thereof (for example, LiF) .

Hereinafter, the organic light emitting diode 200 according to another embodiment of the present invention will be described in detail with reference to FIGS. 6 to 10. FIG.

6, an organic light emitting diode 200 according to another embodiment of the present invention includes a first electrode 210, a second electrode 220, and first and second electrodes 210 and 220 And an organic medium 250 between the organic medium 250 and the organic medium 250.

The first and second electrodes 210 and 220 may be formed as described above with reference to the embodiment of FIG.

The organic medium 250 may include a first organic light emitting unit 230.1 on the first electrode 210, an intermediate connector 240.1 on the first organic light emitting unit 230.1, , And the intermediate connection portion 240.1 includes a compound having an intramolecular electron transfer characteristic represented by Formula 1. [

More specifically, the organic medium 250 includes N organic light emitting units 230.1, 230.2, ..., 230 (N-1), 230.N, and (N-1) intermediate connection portions 240.1, 240.2, ..., 240. (N-1), respectively, Where N is an integer greater than or equal to 2.

7, the first organic light emitting unit 230.1 formed directly on the first electrode 210 includes a hole injection layer 231a formed directly on the first electrode 210, A hole transporting layer 232a on the injection layer 231a, a light emitting layer 233a on the hole transporting layer 232a and an electron transporting layer 234a on the light emitting layer 233a.

The Nth organic light emitting unit 230.N contacting the second electrode 220 is formed just above the (N-1) th intermediate connection 240. (N-1), as illustrated in FIG. The light emitting layer 233b on the hole transporting layer 232b, the electron transporting layer 234b on the light emitting layer 233b and the electron injecting layer 235b on the electron transporting layer 234b .

Each of the organic light emitting units 230.2, ..., 230 (N-1) disposed between the first organic light emitting unit 230.1 and the Nth organic light emitting unit 230.N includes The hole transporting layer 232c, the electron transporting layer 234c, and the light emitting layer 233c therebetween.

The hole injecting layer 231a, the hole transporting layers 232a, 232b and 232c, the light emitting layers 233a, 233b and 233c of the organic light emitting units 230.1, 230.2, ), The electron transporting layers 234a, 234b, and 234c, and the electron injecting layer 235b may be formed as described above with reference to the embodiment of FIG. 5, respectively.

Alternatively, the hole injection layer 231a may be formed of a material of a common hole injection layer such as DNTPD, CuPc, HAT-CN, or the like.

Each of the intermediate connections 240.1, 240.2, ..., and 240 (N-1) of the present invention includes an n-type charge generation layer 241 and the n- Type charge generation layer 242 on the p-type charge generation layer 241.

When an electric field is applied between the first and second electrodes 210 and 220 of the organic light emitting diode 200, for example, the n-type charge generation layer 241 of the first intermediate connection portion 240.1 generates electrons The p-type charge generation layer 242 transmits the electrons to the electron transport layer 234a of the first organic light emitting unit 230.1 in contact therewith. The p-type charge generation layer 242 generates holes, And transfers the holes to the hole transport layer 232b or 232c of the unit 230.2.

The n-type charge generating layer 241 may be formed of a metal-doped electron transporting material having a low work function value. Specifically, the n-type charge generation layer 241 is formed of an organic compound (for example, 4,7-diphenyl-1,10-phenanthroline (Bphen)) containing a heterocyclic ring containing a nitrogen atom And may be formed by doping with an alkali metal or an alkaline earth metal. Wherein the organic compound has from 20 to 60 carbon atoms and the alkali metal is selected from Li, Na, K, Rb, Cs, Fr and Yb and the alkaline earth metal is selected from the group consisting of Be, Mg, Ca, Sr, Ra. &Lt; / RTI &gt; The doping concentration of the alkali metal or alkaline earth metal may be 0.5 to 10% based on the volume of the organic compound.

The p-type charge generation layer 242 includes a compound having an intramolecular charge transfer property represented by the above-mentioned formula (1).

Alternatively, the p-type charge generation layer 242 may include the hole transporting material of the hole transporting layers 232a, 232b, and 232c and the compound of the above Formula 1. [ In this case, the content of the compound in the p-type charge generation layer 242 may be 0.5 to 50% by weight.

When the compound contained in the p-type charge generation layer 242 is the ICT-1, ICT-2, ICT-3, ICT-4 or ICT-5, the p-type charge generation layer 242, The content of the above compound may be 5 to 20% by weight.

According to an embodiment of the present invention, the p-type charge generation layer 242 includes a compound having an intramolecular charge transfer characteristic represented by the above-described Formula 1, Efficiency and can be driven with a relatively lower voltage.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

<Mono-type blue organic light emitting device>

Example  One

Washing the patterned ITO glass one after mounting in a vacuum chamber, and under the base pressure of 5-7 × 10 ^-8 torr hole injection layer (NPD: ICT-1, ICT -1 content: 10 wt%, thickness: 50Å), A hole transport layer (NPD, thickness: 800 Å), a blue light emitting layer (thickness: 200 Å), an electron transport layer (thickness: 120 Å), an electron injection layer (LiF, thickness: 5 Å) Glass to form a mono-type blue organic light-emitting device.

Example  2

A blue organic light emitting device of a mono type was completed in the same manner as in Example 1, except that the hole injection layer was formed to have a thickness of 100 ANGSTROM.

Comparative Example  One

A mono-type blue organic light emitting device was completed in the same manner as in Example 1, except that the hole injection layer was formed to have a thickness of 100 ANGSTROM by HAT-CN.

The driving voltage (V), the luminance (cd / m ² ) and the luminance (cd / m ² ) were measured with respect to the current density of 10 mA / cm ^{2 for} the mono-type blue organic light emitting devices manufactured in Examples 1, , And the external luminous efficiency (%), respectively. The results are shown in Table 1 below.

The driving voltage (V) Brightness (cd / m ² ) External luminous efficiency (%) Example 1 3.9 330 3.9 Example 2 3.8 347 4.1 Comparative Example 1 4.1 340 4.1

As can be seen from the above Table 1, the organic light emitting devices manufactured by Examples 1 and 2 showed lower driving voltage characteristics than the organic light emitting devices manufactured by Comparative Example 1, respectively. In particular, the organic light emitting device manufactured in Example 2 was superior to the organic light emitting device manufactured in Comparative Example 1 in terms of luminance characteristics.

< Laminated type  Blue organic light emitting element>

Example  3

Washing the patterned ITO glass one after mounting in a vacuum chamber and, 5 ~ 7 × 10 ^-8 torr under a base pressure of a hole injection layer (HAT-CN, thickness: 50Å), a hole transport layer (NPD, thickness: 600Å), blue Type charge generation layer (BPen: Li, Li content: 2 wt%, thickness: 150 ANGSTROM), p-type charge generation layer (NPD: ICT-1 , A hole transport layer (NPD, thickness: 390 Å), a blue light emitting layer (thickness: 300 Å), an electron transport layer (thickness: 380 Å), an electron injection layer (LiF, thickness: 5 Å) ) And a cathode electrode (Al, thickness: 1000 ANGSTROM) were successively formed on the ITO glass, thereby completing a layered blue organic light emitting device.

Example  4

Emitting layer was formed in the same manner as in Example 3 except that the p-type charge generation layer was formed to have a thickness of 100 ANGSTROM.

Comparative Example  2

The stacked blue organic light emitting device was completed in the same manner as in Example 3 except that the p-type charge generation layer was formed to have a thickness of 100 ANGSTROM as HAT-CN.

(Cd / m &lt; ² &gt;), a luminance (cd / m &lt; ² &gt;) and a luminance (cd / m &lt; ² &gt;) were measured with respect to the current density of 10 mA / cm &lt; ² &gt; with respect to the laminated blue organic light emitting devices manufactured in Examples 3, And external luminous efficiency (%) were measured. The results are shown in Table 2 below.

The driving voltage (V) Brightness (cd / m ² ) External luminous efficiency (%) Example 3 9.0 561 6.7 Example 4 8.8 614 7.3 Comparative Example 2 9.3 544 6.6

As can be seen from the above Table 1, the organic light emitting devices manufactured by Examples 3 and 4 have lower luminance and higher luminance characteristics as compared with the organic light emitting device manufactured by Comparative Example 1, Luminescence efficiency characteristics were shown.

100: TFT substrate 200: organic light emitting element
300: encapsulation structure 400: circular polarizer
500: front module

Claims (15)

A first electrode;
A second electrode; And
An organic medium between the first and second electrodes,
Wherein the organic medium comprises a compound represented by Formula 1 below:
&Lt; Formula 1 >

Wherein R ₁ and R ₂ are selected from the group consisting of a substituted or unsubstituted alkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted hetero A heterocyclic group, and may be bonded to each other to form a ring or not to form a ring,
n is an integer of 1 to 5,
Ar is a substituted or unsubstituted C ₅ -C ₃₀ ring or fused ring or a heterocycle or fused heterocycle of 5 to 30 nucleus atoms,
R ₃ is selected from the group consisting of hydrogen, deuterium, halogen, cyano, trifluoromethyl, nitro, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heterocycle Group, and the following functional groups:

,

,

,

. The method according to claim 1,
Wherein Ar has a substituted or unsubstituted arylamine group as a substituent. The method according to claim 1,
Wherein the compound is a compound represented by any one of the following formulas:

,

,

,

,

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,

,

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,

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,

,

,

,

,

,

,

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,

,

,

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,

,

,

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. The method according to claim 1,
The compound,

,

,

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, or

&Lt; / RTI &gt; The method according to claim 1,
The organic medium may include,
A hole injection layer on the first electrode;
A hole transport layer on the hole injection layer; And
And a light emitting layer on the hole transporting layer,
Wherein the hole injection layer comprises the compound. 6. The method of claim 5,
Wherein the hole injection layer comprises the hole transporting material of the hole transporting layer and the compound, and the content of the compound in the hole injection layer is 0.5 to 50 wt%. The method according to claim 6,
The compound

,

,

,

, or

ego,
Wherein the content of the compound in the hole injection layer is 5 to 20 wt%. The method according to claim 1,
The organic medium may include,
A first organic light emitting unit on the first electrode;
An intermediate connector on the first organic light emitting unit; And
And a second organic light emitting unit on the intermediate connection portion,
Wherein the intermediate connection portion comprises the compound. 9. The method of claim 8,
The intermediate connection portion
An n-type charge generation layer on the first organic light emitting unit; And
And a p-type charge generation layer on the n-type charge generation layer,
Wherein the p-type charge generation layer comprises the compound. 10. The method of claim 9,
Wherein the first organic light emitting unit comprises:
A hole injection layer on the first electrode;
A first hole transport layer on the hole injection layer;
A first light emitting layer on the first hole transporting layer; And
And a first electron transport layer on the first light emitting layer,
Wherein the second organic light emitting unit comprises:
A second hole transport layer on the p-type charge generation layer;
A second light emitting layer on the second hole transporting layer; And
And a second electron transport layer on the second light emitting layer,
Wherein the p-type charge generation layer comprises the hole transporting material and the compound of the first or second electron transporting layer, wherein the content of the compound in the p-type charge generating layer is 0.5 to 50 wt% Organic light emitting device. 11. The method of claim 10,
The compound

,

,

,

, or

ego,
Wherein the content of the compound in the p-type charge generation layer is 5 to 20 wt%. 10. The method of claim 9,
Wherein the n-type charge generation layer is formed by doping an alkali metal or an alkaline earth metal with an organic compound including a heterocycle containing a nitrogen atom. 13. The method of claim 12,
Wherein the organic compound has 20 to 60 carbon atoms. 13. The method of claim 12,
Wherein the alkali metal is selected from Li, Na, K, Rb, Cs, Fr, and Yb,
The alkaline earth metal is selected from Be, Mg, Ca, Sr, Ba, and Ra,
Wherein the doping concentration of the alkali metal or alkaline earth metal is 0.5 to 10% based on the volume of the organic compound. A TFT substrate including a thin film transistor;
An organic light emitting element according to any one of claims 1 to 14 formed on the substrate; And
And an encapsulation structure formed on the substrate and the organic light emitting device to cover the organic light emitting device.

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