WO2006080315A1

WO2006080315A1 - Organic electroluminescent device, method for manufacturing same, and organic electroluminescent display panel

Info

Publication number: WO2006080315A1
Application number: PCT/JP2006/301064
Authority: WO
Inventors: Koji Ishizuya
Original assignee: Sharp Kabushiki Kaisha
Priority date: 2005-01-26
Filing date: 2006-01-24
Publication date: 2006-08-03

Abstract

Disclosed is an organic electroluminescent device comprising an anode (11), a cathode (14), an organic layer (12) arranged between the anode (11) and the cathode (14) and including at least a light-emitting layer (21), and an electron injection layer (13) arranged between the cathode (14) and the organic layer (12) and including at least an oxide layer (23) and a halide layer (22). The anode (11), organic layer (12), halide layer (22), oxide layer (23) and cathode (14) are arranged in layers in this order. With this structure, the organic EL device is improved in the electron injection efficiency and can be driven at low voltage.

Description

Specification

ORGANIC ELECTRIC ELECTROLUMINESCENCE ELEMENT AND ITS MANUFACTURING METHOD, ORGANIC ELECTROMINESSENCE DISPLAY PANEL

Technical field

[0001] The present invention relates to an organic electoluminescence element.

Background art

Organic electroluminescence devices (hereinafter referred to as “organic EL devices”), which is a type of electroluminescent device, are self-luminous, all-solid-state devices, so they have high visibility and are also CRTs and plasma displays. Compared with liquid crystal displays, the thickness of the device can be reduced, and the drive power is also low!

FIG. 10 is a cross-sectional view showing a schematic configuration of a conventional organic EL element.

As shown in FIG. 10, an organic EL element is laminated on a substrate in this order on an anode, a hole transport layer, a light emitting layer, an electron injection layer, and a cathode force S. The hole transport layer and the light emitting layer correspond to an organic layer.

[0005] The anode has a function of injecting holes into the organic layer. The hole transport layer has a function of improving the transport efficiency of holes injected from the anode to the light emitting layer. The cathode has a function of transporting electrons to the electron injection layer. The electron injection layer has a function of improving the injection efficiency of electrons transported by the cathode into the light emitting layer. In an organic EL element, excitons (excitons) are generated by recombining holes injected from the cathode and electrons injected from the cathode in the light emitting layer, and the excitons are deactivated. It is designed to emit light using the emission of light.

In the organic EL element, the electron injection layer is preferably made of a material having a low work function from the viewpoint of realizing high injection efficiency of electrons from the cathode to the light emitting layer. Examples of the material having a low work function include alkali metals and alkaline earth metals such as calcium (Ca), barium (Ba), and lithium (Li).

[0007] However, when the alkali metal or alkaline earth metal is used as the electron injection layer, the alkali metal or alkaline earth metal is very unstable to oxygen or moisture. It is not a chemically stable material because it reacts with oxygen and water to produce oxides and hydroxides. Therefore, these electron injection layers that also have alkali metal or alkaline earth metal power are suitable from the viewpoint of the efficiency of electron injection into the organic layer, but they react with oxygen and moisture, resulting in electron injection. There is a problem of reduced efficiency

. In addition, when oxides or hydroxides are generated, there is a problem that peeling occurs at the interface between the electron injection layer and the cathode and the Z or organic layer, resulting in a decrease in light emission luminance of the organic EL element.

[0008] Therefore, for example, Patent Document 1 proposes to insert an alkali metal or alkaline earth metal oxide as an electron injection layer between the organic layer and the cathode in order to solve the above problem. It has been. These alkali metal and alkaline earth metal oxides have a low work function. Therefore, by using an alkali metal or alkaline earth metal oxide as the electron injection layer, high electron injection efficiency into the organic layer can be expected, and since it is an oxide, it reacts with oxygen. It does not occur, the adhesion to other layers is stabilized, and electrons are efficiently injected into the light-emitting layer.

[0009] Further, for example, in Patent Document 2, an oxide insulating layer and a fluorine compound insulating layer are laminated in this order on an organic light emitting layer, and a cathode is formed on the fluorine compound insulating layer. The proposed configuration is disclosed.

[Patent Document 1]

US Patent No. 6563262 (Registered; May 13, 2003)

[Patent Document 2]

JP 2001-93671 (Opened; April 6, 2001)

However, the conventional configuration described above has a problem in that the electron injection efficiency is poor and the driving voltage of the organic EL element is high.

[0010] Specifically, the organic EL device using an alkali metal or alkaline earth metal oxide disclosed in Patent Document 1 as an electron injection layer is an element using an alkali metal or alkaline earth metal as an electron injection layer. In contrast, the driving voltage of an organic EL device in which the electron injection layer is made of an oxide of an alkali metal or an alkaline earth metal is lower than that of the metal injection layer. Same as drive voltage of organic EL device composed of alkaline earth metal Degree. Therefore, at present, the driving voltage of organic EL elements is high and the power consumption is large, and further reduction in driving voltage is required.

Similarly, in the case of the organic EL element disclosed in Patent Document 2, the driving voltage of the organic EL element is high, the power consumption is large, and further reduction of the driving voltage is required.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an organic EL element that can improve electron injection efficiency and can be driven at a low voltage.

Disclosure of the invention

[0013] The inventors of the present application have conducted intensive research on the electron injection layer in order to improve the electron injection efficiency, and as a result, the structure of the electron injection layer is specified to include at least the organic light emitting layer. It has been found that electrons can be efficiently injected into the organic layer, that is, the efficiency of injection of electrons into the organic layer can be improved, and the present invention has been completed.

[0014] That is, in order to solve the above problems, the organic EL device according to the present invention includes an anode, an anode, and an organic layer including at least an organic light emitting layer provided between the anode and the cathode; An anode, an organic layer, a halide layer, an oxide layer, and a cathode provided between the cathode and the organic layer, the electron injection layer including at least an oxide layer and a halide layer. Are stacked in this order.

[0015] Since the organic EL element having the above-described structure has the above-described electron injection layer, the efficiency of electron injection into the organic layer is significantly improved as compared with the conventional case, and as a result, the drive voltage is reduced. Therefore, an organic EL element with low power consumption can be obtained. In addition, since the electron injection layer is formed to include an acid compound and a halogen compound that are very stable with respect to oxygen, even when the organic EL device is placed in an oxygen atmosphere. The electron injection layer does not oxidize. In other words, with the above structure, the electron injection efficiency of the electron injection layer into the light emitting layer does not decrease even in an oxygen atmosphere, and the electron injection layer can be peeled off at the interface with other layers. No organic EL element can be obtained. Therefore, by adopting the above-described configuration, it is possible to realize an organic EL element with low power consumption and less element deterioration even for a long time as compared with the conventional case.

In the organic EL device according to the present invention, the oxide layer is in contact with at least a part of the cathode, and Z or a halide layer is in contact with at least a part of the organic layer. The configuration is more preferable.

[0017] Further, the organic EL device according to the present invention preferably has a configuration in which the halide layer and the oxide layer are in contact with each other.

[0018] Further, in the organic EL device according to the present invention, the material constituting the oxide layer is more preferably an alkali metal or alkaline earth metal oxide. Thereby, the current density and the light emission luminance can be further improved as compared with the conventional case.

[0019] Further, in the organic EL device according to the present invention, the material constituting the halide layer is more preferably an alkali metal or alkaline earth metal halide. Thereby, the current density and the light emission luminance can be further improved as compared with the conventional case.

[0020] Further, in the organic EL device according to the present invention, it is more preferable that the material constituting the halide layer is a fluoride. Thereby, the current density and the light emission luminance can be further improved as compared with the conventional case.

In addition, the organic EL device according to the present invention preferably has a configuration in which the thickness of the electron injection layer is in the range of 0.1 to 20 nm.

[0022] In the organic EL device according to the present invention, the material constituting the cathode is preferably a transparent conductive oxide.

[0023] When the cathode is made of a transparent conductive oxide, light from the light emitting layer can be extracted also from the cathode side.

[0024] In addition, when the anode and the cathode are made of a transparent conductive material, light can also be extracted from both side forces of the cathode and the cathode.

[0025] In order to solve the above problems, a method for producing an organic EL element according to the present invention includes an anode, a cathode, and an organic layer including at least an organic light emitting layer provided between the anode and the cathode; A method for producing an organic electoluminescence device comprising an electron injection layer provided between the cathode and the organic layer, the halide forming a halide layer on at least a part of the surface of the organic layer A layer forming step and an oxide layer forming step of forming an oxide layer on at least a part of the halide layer.

[0026] With the above configuration, it is possible to manufacture an organic EL element in which an organic layer, a halide layer, an oxide layer, and a cathode are stacked in this order. In other words, according to the above manufacturing method, Compared with, organic EL elements can be manufactured with low power consumption and little element degradation even for a long time.

[0027] In order to solve the above-described problems, an organic electoluminescence display panel according to the present invention includes the organic EL element.

[0028] By adopting the above configuration, since the organic EL element with low power consumption and less element deterioration even for a long time is used as compared with the conventional case, the display quality is deteriorated for a long time with low power consumption. There can be provided no organic-electto-luminescence display panel.

[0029] Still other objects, features, and advantages of the present invention will be sufficiently enhanced by the following description. The benefits of the present invention will become apparent from the following description with reference to the accompanying drawings.

Brief Description of Drawings

[0030] FIG. 1 is a cross-sectional view illustrating an example of an electron injection layer in an organic EL element that is useful in the present embodiment.

FIG. 2 is a cross-sectional view illustrating another example of an electron injection layer.

FIG. 3 is a cross-sectional view illustrating still another example of the electron injection layer.

FIG. 4 is a cross-sectional view illustrating still another example of the electron injection layer.

FIG. 5 is a cross-sectional view showing another example of an organic EL element.

FIG. 6 (a) is a cross-sectional view showing a schematic configuration of the passive matrix drive type organic EL display panel.

FIG. 6 (b) is a view of the organic EL display panel viewed from the substrate side.

FIG. 7 is a cross-sectional view showing a schematic configuration of an active matrix driving type organic EL display panel.

[Fig. 8] A graph showing the measured current density of the current flowing in the organic EL element with respect to the driving voltage of the organic EL element.

FIG. 9 is a graph showing the measured luminance of the organic EL device with respect to the driving voltage of the organic EL device.

Explanation of symbols 1 Organic EL device

10 Board

11 Anode

12 Organic layer

13 Electron injection layer

14 Cathode

20 Hole transport layer

21 Light-emitting layer

22 Halide layer

23 Oxide layer

30 OLED display panel

BEST MODE FOR CARRYING OUT THE INVENTION

[0032] An embodiment of the present invention will be described as follows.

[0033] The organic EL device according to the present embodiment is provided between an anode, a cathode, an organic layer including at least an organic light emitting layer provided between the anode and the cathode, and between the cathode and the organic layer. And an electron injection layer comprising at least an oxide layer and a halide layer provided between the cathode and the organic layer. The oxide layer is in contact with at least a part of the cathode, and the Z or halogen oxide layer is in contact with at least a part of the organic layer. This will be described below.

[0034] (Organic layer)

The organic layer includes at least an organic light emitting layer (hereinafter simply referred to as a light emitting layer). The organic layer may be a single-layer structure including only a light-emitting layer, or a stacked structure including a plurality of layers including a light-emitting layer and a layer having other functions. Specifically, for example, as the configuration of the organic layer, the following configurations can be cited. The present invention is not limited to these.

(1) Light emitting layer

(2) Hole transport layer Z light emitting layer

(3) Light emitting layer Z electron transport layer (4) Hole transport layer Z light emitting layer Z electron transport layer

(5) Hole injection layer Z hole transport layer Z light emitting layer Z electron transport layer

(Light emitting layer)

The light emitting layer may be formed by, for example, a resistance heating vapor deposition method or an electron beam vapor deposition method using a vacuum vapor deposition apparatus, or a spin coating method, a doctor blade method, a discharge coating method, a spray using a light emitting layer forming coating solution. It is possible to form a film by a wet process such as a coating method, an inkjet method, a relief printing method, an intaglio printing method, a screen printing method, or a micro gravure coating method.

[0035] Examples of the material constituting the light emitting layer include light emitting materials. Specific examples of the light-emitting material include aromatic dimethylidene compounds such as 4,4'-bis (2,2'-diphenyl) -biphenyl (DPVBi), 5-methyl-2, and the like. -[2- [4- (5-Methyl-2-benzoxazolyl) phenol] bulu] oxazole compounds such as benzoxazole, 3- (4-biphenyl) -4-phenyl-5 --Butylphenol-Triazole derivatives such as 1,2,4-triazole (TAZ), styrylbenzene compounds such as 1,4-bis (2-methylstyryl) benzene, thiopyrazine dioxide derivatives, Fluorescent organic materials such as benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, diphenoquinone derivatives, and fluorenone derivatives, azomethine zinc complexes, and fluorescent organic materials such as (8-hydroxyquinolinato) aluminum complexes (Alq)

Three

Low molecular light emitting materials such as metal compounds, or, for example, poly (2-decyloxy-1,4-phenylene) (DO-PP), poly [2,5-bis- [2- (N, N, N-triethylammo) ethoxy]-1, 4-phenol-alt-1,4-phenolene dibromide (PPP-NEt3 +), poly [2- (2'-ethylhexyloxy)- 5-methoxy-1,4-phenylenevinylene] (MEH-PPV), poly [5-methoxy- (2-propanoxysulfo) -1,4-phenylenevinylene] (MPS-PPV), poly [2,5-bis- (hexyloxy) -1,4-phenylene- (1-cyanobilene)] (CN-PPV), poly (9,9-dioctylfluorene) (PDAF), Examples thereof include polymer light emitting materials such as polyspiro (PS).

[0036] Further, the light emitting layer can be formed of one kind of light emitting material among the above light emitting materials, or can be formed by combining a plurality of light emitting materials among the above light emitting materials. . In addition to the above light-emitting materials, the light-emitting layer may include, for example, a light-emission assisting agent, a charge transport material, an additive such as a donor receptor, a light-emitting dopant, a leveling agent, a charge injection material, It is also possible to contain knotting oil and the like. Examples of the binding fat include, but are not limited to, for example, polycarbonate, polyester, and the like.

[0037] (Hole transport layer)

The hole transport layer can be formed, for example, by the same method as the method for forming the light emitting layer. Further, as a material constituting the hole transport layer (hole transport material), specifically, for example, porphyrin compounds, Ν, Ν, -bis- (3-methylphenol)-, Ν, -bis -(Phenol)-Benzidine (TPD), Ν, Ν, -Di (Naphthalene-1-yl)-Aromatic tertiary amines such as Ν, Ν, -Diphenyl-Benzidine (NPD) , Hydrazone compounds, quinacridone compounds, low molecular weight materials such as stillamin compounds, polyarine, 3,4-polyethylenedioxythiophene Ζpolystyrene sulfonate (PEDOT / PSS), poly (triphenylamine) Derivatives), polymer materials such as polybulucarbazole (PVCz), polymer materials precursors such as poly (P-furene-vinylene) precursors, poly (P-naphthalene vinylene) precursors, etc. It is not limited.

[0038] Further, the hole transport layer is formed of one kind of hole transport material among the hole transport materials, or formed by combining a plurality of hole transport materials among the hole transport materials. It is possible to do. In addition to the above hole transport material, the hole transport layer may contain, for example, an additive such as a donor receptor, a leveling agent, a binding resin, and the like. For example, polycarbonate and polyester are not limited to the binding fats and oils.

[0039] (Electron transport layer)

The electron transport layer can be formed, for example, by the same method as the method for forming the light emitting layer. Specific examples of materials constituting the electron transport layer (electron transport material) include, for example, low molecular weight materials such as oxadiazole derivatives, triazole derivatives, benzoquinone derivatives, naphthoquinone derivatives, and fluorenone derivatives, poly [oxaziazole], and the like. There are no particular restrictions on the high molecular weight material.

[0040] Further, the electron transport layer may be formed of one electron transport material of the electron transport materials, or may be formed by combining a plurality of electron transport materials of the electron transport materials. Is possible. In addition to the electron transport material, the electron transport layer may be, for example, a donor or It is possible to contain additives such as acceptors, leveling agents, binding fats and the like. Examples of the binding fat include, but are not limited to, for example, polycarbonate, polyester and the like.

[0041] (Hole injection layer)

The hole injection layer can be formed by, for example, a method similar to the method for forming the light emitting layer. In addition, specific examples of materials constituting the hole injection layer (hole injection material) include, for example, copper phthalocyanine (CuPc), star bust type amine (eg, m-MTDATA), and the like. Is not to be done.

[0042] Further, the hole injection layer is formed of one kind of hole injection material among the hole injection materials, or formed by combining a plurality of hole injection materials among the hole injection materials. It is possible to do. In addition to the above hole injection material, the hole injection layer can contain, for example, additives such as donors and acceptors, leveling agents, binder resins and the like. Examples of the binding fat include, but are not limited to, for example, polycarbonate, polyester and the like.

[0043] (Substrate)

The organic EL covered in this embodiment can be manufactured on a substrate. Examples of the substrate include inorganic materials such as glass and quartz, plastics such as polyethylene terephthalate, substrates that have insulating materials such as ceramics such as alumina, metal substrates such as aluminum and iron, SiO and organic A substrate coated with an insulating material such as an insulating material, or

2

In addition, the force that can be used is that the surface of a metal substrate such as aluminum or iron that has been subjected to an insulation treatment by a method such as anodization is not limited thereto.

[0044] (Anode)

The material constituting the anode is preferably composed of a material having a high work function so that holes can be easily injected into the organic layer. Specific examples of materials having a large work function and suitable for hole injection include indium stannate (ITO) (work function φ = 5. OeV), indium zinc oxide (IZO) ( = 5. OeV) and other transparent conductive oxides, gold (Au) (= 5. leV), platinum (Pt) (φ = 5.65 eV), Nikkenore (Ni) (φ = 5. 15 eV), etc. Metal materials. And, as a method of forming the anode (film formation method), for example, Examples include resistance heating evaporation, electron beam evaporation, ion plating, laser exposure, sputtering, and CVD. In addition, a material in which these conductive materials are dispersed in a resin material can be used. Examples of the resin material that can be used include, but are not limited to, acrylic resin, epoxy resin, and the like.

[0045] The material constituting the cathode is not particularly limited as long as it is a conductive material capable of transporting electrons to the electron injection layer. Specific examples of the conductive material include aluminum (A1), Metal materials such as silver (Ag), nickel (Ni), palladium (Pd), platinum (Pt), indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) And transparent conductive oxides such as Examples of the cathode forming method (film forming method) include a resistance heating evaporation method, an electron beam evaporation method, an ion plating method, a laser abrasion method, a sputtering method, and a CVD method. In addition, a mixture of the above conductive materials can be used for the cathode. In addition, a material in which these conductive materials are dispersed in a resin material can be used. Examples of the resin material that can be used include acrylic resin, epoxy resin, and the like, but are not limited thereto.

In addition, for example, in the case where the anode is formed on the substrate and the anode or the substrate does not have translucency, the cathode has translucency in order to extract light from the organic EL element. It is necessary to In addition, for example, when the cathode is formed on the substrate and the cathode or the substrate has a light-transmitting property, the anode has a light-transmitting property in order to extract light from the organic EL element. There is a need. When a transparent conductive material (for example, a transparent conductive oxide) is used as the material constituting the cathode and anode, the force on both sides (negative electrode side and anode side) of the organic EL element is also light. Can be taken out.

[0047] (Electron injection layer)

The electron injecting layer in the organic EL device which is effective in the present embodiment is configured to include at least an oxide layer and a no-logous layer. The halide layer is disposed closer to the organic layer than the oxide layer, and the oxide layer is disposed closer to the cathode than the halide layer. In other words, the organic EL element has an anode, an organic layer, a halide layer, an oxide layer, and a cathode laminated in this order. In addition, the above "product in this order “Layered” simply indicates a relative stacking order, and for example, other layers may be formed between the layers. In particular, the electron injection layer only needs to include at least an oxide layer and a halide layer, for example, between an oxide layer and a halide layer, and between a halide layer and an organic layer. And at least one between the oxide layer and the cathode

Other layers may be formed. The specific configuration of the electron injection layer will be described later.

[0048] (Oxide layer)

The oxide layer can be formed of one kind of oxide or a mixture of acids. Further, as a material constituting the oxide layer, a peroxide deviating from the stoichiometric composition ratio of the oxide or an oxide having oxygen vacancies can be used. Suitable materials for forming the oxide layer include, for example, aluminum oxide (Al 2 O 3) and lanthanum oxide (La 2 O 3).

2 3 2 3

, Cerium oxide (CeO, CeO), yttrium oxide (YΟ), zirconium oxide (ZrO)

2 2 3 2 3 2 etc.

[0049] Furthermore, the oxide layer more preferably contains an alkali metal or alkaline earth metal oxide. Since alkali metals and alkaline earth metal oxides have a low work function, the use of the alkali metal or alkaline earth metal oxide as the oxide layer improves the efficiency of electron injection into the organic layer. Can be made. Among the above alkali metal or alkaline earth metal oxides, lithium oxide (Li 0), acid potassium (K 2 O 2)

twenty two

), Rubidium oxide (Rb 2 O), cesium oxide (Cs 2 O) (= 0.75 eV), calcium oxide

twenty two

(CaO) (φ = 1.76 eV), strontium oxide (SrO) (φ = 1.27 eV), and barium oxide (BaO) (φ = 0.99 eV) are preferable as the material constituting the oxide layer.

[0050] (halide layer)

More preferably, the halide layer also comprises at least one halide strength selected from the group consisting of fluoride, chloride, bromide, and iodide strength. The halogenated layer can be formed of a mixture of one kind of halogenated material and a nonogenous material. As a suitable material constituting the halogenated material layer, for example. Aluminum fluoride (A1F), iron fluoride (FeF), scandium fluoride (ScF), lanthanum fluoride (LaF),

3 3 3 3 Salt-aluminum (A1C1), salt-lanthanum (LaCl), and the like. [0051] The halide layer is more preferably made of an alkali metal or alkaline earth metal halide. By using the alkali metal or alkaline earth metal halide insulating layer as the halide layer, the electron injection barrier height between the organic layer and the cathode can be lowered. Examples of alkali metal or alkaline earth metal halides include lithium fluoride (LiF), sodium fluoride (NaF), potassium fluoride (KF), rubidium fluoride (RbF), and cesium fluoride (CsF). ), Magnesium fluoride (MgF), calcium fluoride (CaF), strontium fluoride (SrF), barium fluoride (

2 2 2

Fluorides such as BaF), lithium chloride (LiCl), potassium chloride (KC1), rubidium chloride (Rb

2

C1), cesium chloride (CsCl), calcium chloride (CaCl), strontium chloride (SrCl),

2 2 Chlorides such as barium chloride (BaCl), potassium bromide (KBr), odorous rubidium (RbBr), odor

2

Cesium fluoride (CsBr), Calcium bromide (CaBr), Strontium bromide (SrBr), Bali bromide

2 2 Bum (BaBr) and other bromides, potassium iodide (KI), rubidium iodide (Rbl), cesium iodide

2

(Csl), calcium iodide (Cal), strontium iodide (Sri), barium iodide (Bal

2 2 2

) And the like.

[0052] The halide layer is particularly preferably made of a fluoride. By using the fluoride as the halide layer, the height of the electron injection barrier between the organic layer and the cathode can be further reduced. Of the above fluorides, LiF, RbF, CsF, CaF, SrF, and BaF are particularly preferable.

2 2 2

[0053] (Configuration of electron injection layer)

FIG. 1 is a cross-sectional view illustrating an example of the electron injection layer 13 in the organic EL element 1 according to the present embodiment. Here, a configuration example of the electron injection layer 13 will be described with reference to FIG. In the following description, the force for explaining the case where the electron injection layer 13 also has two layer forces of the halide layer 22 and the oxide layer 23 is not particularly limited.

[0054] When the electron injection layer 13 is composed of a stack of an oxide layer 23 and a halide layer 22, the oxide layer 23 is in contact with the cathode 14, and the halide is In contact with the organic layer 12. Specifically, when the halide layer 22 and the oxide layer 23 have a sufficient thickness, the halide layer 22 and the oxide layer 23 are formed as shown in FIG. And a structure in which both layers are laminated. In this case, the halide layer 22 is oxidized with the organic layer 12. The oxide layer 23 is in contact only with the cathode 14 and the halide layer 22.

Further, in the organic EL element 1 according to the present embodiment, the electron injection layer 13 may be distributed in an island shape with respect to the organic layer 12. More specifically, the halide layer 22 is in contact with only part of the organic layer 12, and Z or the oxide layer 23 is in contact with only part of the cathode 14. Also good. This will be described below.

FIG. 2 is a cross-sectional view illustrating another example of the electron injection layer 13.

In the electron injection layer 13, as shown in FIG. 2, the oxide layer 23 faces the cathode 14 and the halide faces the organic layer 12 in a part of the electron injection layer 13. That is, as shown in FIG. 2, the halide layer 22 is formed so as to be in contact with a portion of the light emitting layer 21 constituting the organic layer 12 and the oxide layer 23. The oxide layer 23 is formed so as to be in contact with the halide layer 22, the light emitting layer 21 (organic layer 12), and the cathode 14.

That is, the halide layer 22 constituting the electron injection layer 13 may be laminated not on the entire surface of the organic layer 12 (here, the light emitting layer 21) but on only a part thereof. In other words, the halogenated material layer 22 may be laminated on the organic layer 12 so as to be distributed in a plurality of island shapes. More specifically, the halide layer 22 is in contact with the organic layer 12 in a plurality of regions.

Here, the “island distribution” will be described. The island distribution indicates that the halide layer 22 is distributed so as to form a plurality of islands with respect to the surface of the organic layer 12.

FIG. 3 is a cross-sectional view illustrating still another example of the electron injection layer 13.

As shown in FIG. 3, the electron injection layer 13 has a halide layer 22 laminated on the entire surface of the organic layer 12, and the oxide layer 23 is formed on the surface of the halide layer 22. They are stacked so that they are distributed in islands. That is, the oxide layer 23 is in contact with only a part of the cathode 14 and the halide layer 22, and the halide layer 22 is in contact with the organic layer 12 (here, the light emitting layer 21) and the oxide layer 23. It is in contact with the material layer 23 and the cathode 14. More specifically, the oxide layer 23 is in contact with the neurogenic layer 22 in a plurality of regions.

FIG. 4 is a cross-sectional view for explaining still another example of the electron injection layer 13. As shown in FIG. 4, the electron injection layer 13 has a halide layer 22 laminated on only a part of the surface of the organic layer 12, and the organic layer 12 and the oxide layer 23. In contact with the cathode 14. The oxide layer 23 is in contact with the cathode 14, the halide layer 22, and the organic layer 12. That is, in this case, the oxide layer 23 and the halide layer 22 are laminated so as to be distributed in a plurality of islands only on a part of the surface of the organic layer 12. Therefore, in this organic EL element 1, there is a portion where the cathode 14 and the organic layer 12 are in contact with each other. Further, in the organic EL element 1, the region where the oxide layer 23 is in contact only with the cathode 14 and the organic layer 12 and the region where the halide transport 22 is in contact only with the cathode 14 and the organic layer 12 Exists.

That is, the electron injection layer 13 according to FIGS. 2 to 4 has an electron concentration portion (protruding portion) for concentrating electrons injected from the cathode in one place. Specifically, it is more preferable to laminate the halide layer 22 and the Z or oxide layer 23 so as to protrude in the cathode direction. Further, for example, the halide layer 22 or the oxide layer 23 is laminated on the entire surface of the organic layer 12 or the halide layer 22, and a plurality of layers are formed on the surface of each halide layer 22 or oxide layer 23. May have a protruding portion (electron concentration portion).

[0065] The thickness of the electron injection layer 13 is preferably in the range of 0.1 to 20 nm. Since the electron injection layer 13 must efficiently inject electrons into the organic layer 12, when the thickness of the electron injection layer 13 is less than 0.1 nm, the effect as the electron injection layer 13 is small, and the organic layer In some cases, sufficient electron injection into 12 is not performed. In particular, when the electron injection layer 13 is contained in the halogenated oxide layer 22 or the oxide oxide layer 23 distributed in an island shape, the thickness of the electron injection layer 13 is less than 0.1 nm. However, if it is too thin, electron injection may not be performed sufficiently. Further, the oxides and halogens constituting the electron injection layer 13 are basically insulators. Therefore, if the electron injection layer 13 is thicker than 20 nm, it becomes difficult for electrons to move through the electron injection layer 13, and as a result, current may not flow through the organic EL element 1. The layer thicknesses of the oxide layer 23 and the halide layer 22 are each preferably in the range of 0.1 to LOnm.

[0066] As described above, the organic EL element 1 according to the present embodiment includes at least the anode 11, the cathode 14, and the light emitting layer 21 provided between the anode 11 and the cathode 14. Layer 12 and an oxide layer 23 and a halogen oxide layer 22 provided between the cathode 14 and the organic layer 12 are reduced. The electron injection layer 13 is included, and the anode 11, the organic layer 12, the halide layer 22, the oxide layer 23, and the cathode 14 are laminated in this order.

[0067] By configuring the electron injection layer 13 as described above, the efficiency of electron injection into the organic layer 12 is remarkably improved, and as a result, the driving voltage is lowered. Is possible. Further, since the electron injection layer 13 is formed to contain an oxide and a halide that are very stable with respect to oxygen, the organic EL element 1 is, for example, placed in an oxygen atmosphere. Even if it exists, the electron injection layer 13 does not oxidize. For this reason, the electron injection efficiency of the electron injection layer 13 into the light emitting layer 21 does not decrease, and the electron injection layer 13 does not peel off at the interface with other layers. In addition, since very stable oxides and halides are used as the material constituting the electron injection layer 13, it is possible to suppress the deterioration of the organic EL element 1 even when used for a long period of time. Can do. Therefore, the organic EL element 1 in the present embodiment can realize the organic EL element 1 with little element deterioration even when used for a long time with low power consumption.

[0068] Next, a method for manufacturing the organic EL element 1 according to the present embodiment will be described. The manufacturing method of the organic EL element 1 includes a step of forming a halide layer 22 on at least a part of the surface of the organic layer 12, and a step of forming the halide layer 22 at least in part of the halide layer 22. And the oxide layer 23 forming step of forming the oxide layer 23.

Specifically, the anode 11 is formed on the substrate 10, and the organic layer 12 including at least the light emitting layer 21 is formed on the anode 11. Then, the halide layer 22 is formed on at least a part (or part or all) of the surface of the organic layer 12. Next, an oxide layer 23 is formed on at least a part of the surface of the halide layer 22 (which may be a part or all of it! /,). Finally, the organic EL element 1 can be manufactured by forming the cathode 14 on the oxide layer 23 so as to be in contact with at least the oxide layer 23.

[0070] In order to form the halide layer 22 on at least a part of the surface of the organic layer 12, for example, an electron beam evaporation method, an ion plating method, a laser exposure method, a sputtering method, a CVD method, etc. Or the like.

In addition, in order to form the oxide layer 23 on the halogen oxide layer 22, for example, an electronic vinyl Vapor deposition method, ion plating method, laser exposure method, sputtering method,

Use a method such as CVD.

[0072] Further, in the method of manufacturing the organic EL element 1, for example, the halide layer 22 is formed only on a part of the surface of the organic layer 12, and the oxide layer 23 is combined with the halide layer 22. It may be formed in contact with the above organic layer 12! /.

[0073] In the method of manufacturing the organic EL element 1, for example, the oxide layer 23 is formed only on a part of the surface of the halide layer 22, and the oxide layer 23, the halide layer 22, The cathode 14 may be formed so as to be in contact with each other. In this case, the halide layer 22 may be formed on the organic layer 12 (entire surface of the laminated surface) which may be formed only on a part of the organic layer 12.

Further, in the method for manufacturing the organic EL element 1, for example, the halide layer 22 is formed on a part of the organic layer 12, and the oxide layer 23 is formed so as to cover the halide layer 22. The cathode 14 may be formed so as to be in contact with the organic layer 12 and the oxide layer 23. In this case, the cathode 14 and the organic layer 12 may be in contact with each other.

[0075] Here, the organic EL element 1 using a transparent conductive material for the cathode 14 will be described.

FIG. 5 is a cross-sectional view showing another example of the organic EL element 1. As shown in FIG. 5, the organic EL element 1 that is useful in the present embodiment may have a configuration in which the cathode 14 also has a transparent conductive acidity. By using a transparent conductive oxide as the cathode 14 of the organic EL element 1, it is possible to take out the light emitted from both the cathode 14 side and the anode 11 side of the organic EL element 1, and the organic EL element 1 It becomes possible to greatly expand the use range of. That is, with the above configuration, it is possible to extract double-sided light of the organic EL element 1 as compared with the conventional configuration in which a transparent conductive oxide is used for the anode 11 and a metal is used for the cathode 14.

Incidentally, in order to obtain a transparent conductive oxide having good transparency and conductivity, it is necessary to form a film in an oxygen atmosphere. In the conventional organic EL, since the electron injection layer 13 is composed of alkali metal or alkaline earth metal, the electron injection layer 13 reacts with oxygen when forming a transparent conductive oxide, and the organic injection layer 13 Although there is a problem of peeling at the interface with the layer 12, the electron injection layer 13 of the organic EL element 1 in the present embodiment is Since the structure includes the halide layer 23 and the halide layer 22, the electron injection layer 13 does not react with oxygen and is stable even in an oxygen atmosphere. Therefore, even if a transparent conductive oxide film is formed on the electron injection layer 13, the electron injection layer 13 is stable without deterioration, so that the electron injection from the electron injection layer 13 to the organic layer 12 efficiently. Can be performed.

[0078] Further, since both the oxide and the halide constituting the electron injection layer 13 have good translucency, the electron injection layer 13 is configured as described above. It is possible to extract the emitted light from both sides of cathode 14 and anode 11 without degradation of organic EL element 1.

Specific examples of the transparent conductive oxide include indium tin oxide (ITO) and zinc oxide (ZnO) of indium zinc oxide (IZO). When these transparent conductive oxides are used as the cathode 14, for example, the cathode 14 is formed by a film forming method such as an electron beam evaporation method, an ion plating method, a laser exposure method, a sputtering method, or a CVD method. be able to. Further, as the transparent conductive oxide, a mixture of the above transparent conductive oxide materials can be used. In addition, a material in which these transparent conductive oxides are dispersed in a resin material can be used. Examples of the resin material that can be used include, but are not limited to, acrylic resin, epoxy resin, and the like.

In the organic EL element 1, it is also possible to use a reflective material that reflects light on the anode 11. By adopting the above-described configuration, it is possible to take out light that has also been emitted with power only on the cathode 14 side. As the reflective material, for example, gold (Au), platinum (Pt), nickel (Ni) and the like have a high work function and high light reflectance, and metal materials are preferred.

[0081] Further, as the anode 11, a hole is easily injected into the organic layer 12 having a large work function on a metal having a high light reflectance such as aluminum (A1) or silver (Ag). It is also possible to use a laminate of ITO and IZO, which are transparent conductive oxides. The configuration of the anode 11 described above is advantageous in that the efficiency of injecting holes into the organic layer 12 is improved and a high light reflectance can be obtained.

[0082] (Organic Elect Mouth Luminescence Display Panel)

Here, a plurality of organic EL elements 1 are provided, and an organic electrification lamp capable of displaying information is provided. The nsence display panel (hereinafter referred to as the organic EL display panel 30) will be described.

FIG. 6 (a) is a cross-sectional view showing a schematic configuration of the organic EL display panel 30 of the above-described passive matrix drive system, and FIG. Surface. With reference to FIG. 6 (a) and FIG. 6 (b), the configuration of the organic EL display panel 30 of the passive matrix drive system will be described. The organic EL display panel 30 of the above passive matrix driving system has a hole transport layer 20, a light emitting layer 21, a halide layer 22, an oxide layer 23, a cathode 14 on a plurality of rows of anodes 11 arranged in a strip shape. Has a laminated structure in which these layers are laminated in this order. The passive matrix driving type organic EL display panel 30 is provided such that the plurality of rows of cathodes 14 arranged in a strip shape are orthogonal to the anode 11, and the intersection of the cathode 11 and the cathode 14 is a light emitting portion. Thus, information can be displayed by a plurality of light emitting units.

FIG. 7 is a cross-sectional view showing a schematic configuration of an active matrix driving type organic EL display panel 30. In the organic EL display panel 30 of the active matrix driving method, as shown in FIG. 7, the organic EL element 1 is formed on the active matrix substrate 31 (substrate 10). The active matrix substrate 31 includes a substrate 34, a plurality of TFTs formed for each pixel on the substrate 34, and a flat film 32 covering these TFTs. Each TFT is provided so as to cover the gate electrode 38, the island-shaped semiconductor layer 40 formed on the gate electrode 38 via the gate insulating film 33, and both ends of the island-shaped semiconductor layer 40. TFT electrodes 36 (source and drain electrodes) (bottom gate structure). Each TFT is connected to the source wiring 39 and the gate wiring 37. The flat film 32 is provided with a through hole 35 reaching the drain electrode of each TFT. On the flat film 32, the organic EL element 1 is formed. The anode 11 of the organic EL element 1 is composed of a transparent conductive film, and is formed for each pixel by patterning the transparent conductive film deposited on the flat film 32 and inside the through hole 35. Yes. Each anode 11 is connected to the corresponding drain electrode of TFT through a through hole 35. These anodes 11 are mutually insulated by insulating films 41 formed so as to cover the respective edge portions of the respective anodes 11 and the through holes 35. A hole transport layer 20, a light emitting layer 21, a halide layer 22, an oxide layer 23, and a cathode 14 are formed (laminated) in this order on the anode 11 and the insulating film. As a result, the organic EL element 1 which is similar to the present embodiment is formed. The organic EL element 1 is not limited to the above configuration, and any organic EL element 1 may be used as long as it is the organic EL element 1 according to the present invention.

The configuration of the organic EL display panel 30 of the active matrix driving system that is useful for the present embodiment is not limited to the above. For example, the TFT may have a top gate structure. In addition, the active matrix driving type organic EL display panel 30 may adopt a voltage driving method that requires two TFTs for each pixel, or a current that requires four TFTs for each pixel. Adopt a drive system.

Note that the organic EL element 1 according to the present embodiment includes an anode 11, a cathode 14, and an organic layer 12 including at least a light-emitting layer 21 provided between the anode 11 and the anode 14; An organic electroluminescent device comprising an electron injection layer 13 provided between a cathode 14 and an organic layer 12, wherein the electron injection layer 13 comprises an oxide layer 23 and a halide layer 22. It may have a layered structure including at least the halide layer 22 facing the organic layer 12, and the oxide layer 23 facing the cathode 14! /.

In addition, in the organic EL device 1 according to the present embodiment, the organic layer 12 is in contact with the halide layer 22 and the oxide layer 23, and the cathode 14 is the halide layer 22. The structure which is not touching may be sufficient.

[0088] Further, the organic EL element 1 according to the present embodiment may have a configuration in which the organic layer 12 and the cathode 14 are in contact with each other. Further, in the organic EL device 1 according to the present embodiment, the cathode 14 is in contact with the halide layer 22 and the oxide layer 23, and the organic layer 12 is coupled with the oxide layer 23. The structure which is not in contact may be sufficient. In addition, the manufacturing method of the organic EL element 1 according to the present embodiment has a configuration in which the oxide layer 23 is further formed in contact with the organic layer 12 in the oxide layer 23 forming step. There may be. In addition, the method of manufacturing the organic EL device 1 according to the present embodiment may be configured such that the cathode 14 is further formed in contact with the halide layer 22 in the cathode 14 forming step. Further, the method of manufacturing the organic EL element 1 according to the present embodiment may be configured such that the cathode 14 is further formed in contact with the organic layer 12 in the cathode 14 forming step.

[0089] Further, the organic EL element 1 which is useful in the present embodiment includes the halogenated material layer 22 and / or More preferably, the oxide layer 22 is not flattened. The organic EL element 1 according to the present embodiment is more preferably formed so that the halide layer 22 has a plurality of protrusions from the organic layer 12. Further, the organic EL element 1 according to the present embodiment is more preferably formed such that the oxide layer 22 has a plurality of protrusions from the halogen layer 22.

[Example]

EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these Examples and a comparative example. In the following examples, as shown in FIG. 1, the anode 11, the hole transport layer 20, the light emitting layer 21, the halide layer 22, the oxide layer 23, and the cathode 14 are arranged in this order on the substrate 10. An organic structure in which the halide layer 22 is in contact only with the light-emitting layer 21 and the oxide layer 23 and the oxide layer 23 is in contact only with the cathode 14 and the halide layer 22 EL element 1 is used. In the comparative example, the electron injection layer 13 having a different configuration is used.

[Example 1]

Here, a method for manufacturing the organic EL element will be described. First, indium stannate (hereinafter referred to as ITO), which is a transparent conductive film, was formed on a 25 mm square substrate with a thickness of 150 nm in a mixed atmosphere of oxygen and argon using a sputtering apparatus. . Next, using the photolithography technique, the ITO was patterned in a stripe shape having a width of 2 mm and a length of 25 mm, and this was used as an anode.

Next, a PEDOT-PSS solution was applied on the anode by a spin coating method and dried at 200 ° C. for 10 minutes to form a hole transport layer. The thickness of the hole transport layer was set to about 70 nm by controlling the concentration of the solution and the number of rotations during spin coating. Next, a solution of a polyfluorene derivative was similarly applied onto the hole transport layer by spin coating, and dried at 150 ° C. for 10 minutes to form a light emitting layer. The film thickness of the light emitting layer was set to about 70 nm by controlling the concentration of the solution and the number of rotations during spin coating.

[0093] Next, a lithium fluoride (LiF) film, which is a fluoride, is formed on the light emitting layer by a resistance heating vapor deposition method in a stripe shape having a width of 2 mm and a length of 25 mm so as to be orthogonal to the stripe of the anode. (Thickness stacking step). Next, oxide barium oxide (BaO) film Is formed on the LiF film in a stripe shape with a width of 2mm and a length of 25mm with a film thickness of 3nm by the electron beam evaporation method (acid-oxide stacking process). The stacked film of BaO was used as the electron injection layer. In other words, in this embodiment, an alkali metal fluoride is used for the halide layer, and an alkaline earth metal oxide is used for the oxide layer. Finally, aluminum (A1) is used as the cathode, and using an electron beam evaporation system, the striped shape is 2 mm wide and 25 mm long so that it has the same shape as the electron injection layer on the BaO thin film, with a thickness of lOOnm. Formed. As a result, an organic EL device having a light emitting surface of 2 mm × 2 mm, which is covered in this example, was obtained.

[0094] Then, device characteristics of the obtained organic EL device were measured. Specifically, the current density of the current flowing in the organic EL element relative to the driving voltage of the organic EL element was measured. In addition, the emission luminance of the organic EL element with respect to the driving voltage of the organic EL element was measured. The results are shown in Figs. 8 and 9, respectively.

[Comparative Examples 1 to 4]

Further, a comparative organic EL element as a comparative example was prepared in the same manner as in Example 1 except for the configuration of the electron injection layer of the organic EL element.

[0096] Specifically, the comparison organic EL device of the configuration of anode Z organic layer ZBa (metal) Z cathode is compared. Example 1, comparison of the organic EL device of configuration of anode Z organic layer ZBaO (oxide) Z cathode is compared. Example 2, Anode Z organic layer ZLiF (halogenated) Z cathode composition comparison Organic EL device Comparative Example 3, Anode Z organic layer ZBaO (oxide) / LiF (halogenated) Z cathode composition comparative organic An EL device was fabricated as Comparative Example 4, respectively. Then, the device characteristics of the comparative organic EL devices of Comparative Examples 1 to 4 were examined. The results are shown in Figs.

[0097] Symbols in Figs. 8 and 9 are as follows.

參: Anode Z Organic layer ZLiF (Halogen) ZBaO (Oxide) Z cathode (Example 1) □: Anode Z Organic layer ZBa (Metal) Z cathode (Comparative example 1)

♦: Anode Z Organic layer ZBaO (Oxide) Z cathode (Comparative example 2)

▲: Anode Z Organic layer ZLiF (Halogenide) Z Cathode (Comparative Example 3)

Δ: Anode Z Organic layer ZBaO (oxide) / LiF (Halogen compound) Z cathode (Comparative example 4) From the result of FIG. 8 above, LiFZBaOZA which is the configuration of the electron injection layer in Example 1 The voltage and current density characteristics of the organic EL device with one structure are 10.8mA Zcm ² at a voltage of 4V, while the comparative organic EL device of BaZAl in which the electron injection layer is made of alkaline earth metal (Comparative Example 1 ) Is a low current density of 2.6 mAZcm ^{2 at a} voltage of 4 V, and the BaOZAl comparative organic EL device (Comparative Example 2) has an electron injection layer made of oxide.The current density is 1.8 mAZcm ^{2 at} a voltage of 4 V Since the injection layer is composed of a halide, the LiFZAl comparative organic EL device (Comparative Example 3) has a voltage of 4 V and a current density of 3 • OmAZcm ^2. It can be seen that the injection layer configuration allows a current to flow at a low voltage. This is because the structure of the electron injection layer in Example 1 can efficiently inject electrons into the organic layer. Also, the structure of the electron injection layer is the anode Z organic layer ZBaO (oxide) / LiF (halogenated material) Z cathode, and the structure of the electron injection layer is opposite to that of the electron injection layer in Example 1. In the comparative organic EL device (Comparative Example 4) stacked on the substrate, the current density is 0.5 mAZcm ² at a voltage of 4 V, which is much higher than the current density of the organic EL device having the electron injection layer configuration of Example 1. The current is flowing through. Therefore, the electron injection layer is not necessarily composed of an oxide and a halide. The anode Z organic layer Z halide Z oxide Z cathode t. With this configuration, it is possible to pass a current through the organic EL element at a low voltage.

FIG. 9 is a graph showing the relationship between the light emission luminance of each organic EL element and the driving voltage of each organic EL element. From the results of FIG. 9 above, the voltage-luminescence luminance characteristic of the organic EL device having the LiFZBaOZAl structure, which is the configuration of the electron injection layer in Example 1, shows a luminance of 614 cdZm ² at a voltage of 4 V, while the comparison of Comparative Example 1 The organic EL device has a low emission luminance of 59 cd / m ² at a voltage of 4 V. The comparative organic EL device of Comparative Example 2 has a light emission luminance of 31 cdZm ² at a voltage of 4 V, and the comparative organic EL device of Comparative Example 3 has Since the emission luminance is 143 cd / m ² at a voltage of 4 V, and the emission luminance is 3 cdZm ² at a voltage of 4 V in the comparative organic EL device of Comparative Example 4, the electron injection in Example 1 is performed. It can be seen that the layer structure can achieve high emission luminance at a low voltage. This is because, as described above with reference to FIG. 8, in the organic EL element having the structure of the electron injection layer in Example 1, electrons can be injected into the organic layer very efficiently. [Example 2]

The electron injection layer halide layer is lithium chloride (LiCl) deposited to a thickness of 6 nm by resistance heating vapor deposition, and the oxide layer is cesium oxide (CsO) 6 nm thick by electron beam vapor deposition.

2

An organic EL device was produced in the same manner as in Example 1 except that the film was formed to a thickness of 2 mm. That is, in this embodiment, an alkali metal salt is used for the halide layer and an alkali metal oxide is used for the oxide layer. Then, the element characteristics (element characteristics when a driving voltage of 4 V was applied) of the obtained organic EL element were measured. The results are shown in Table 1.

[Example 3]

The electron injection layer halide layer is 5n of resistance heating vapor deposition of barium fluoride (BaF).

2

An organic EL device was fabricated in the same manner as in Example 1 except that the film was formed to a thickness of m and the oxide layer was formed to a thickness of 5 nm by an electron beam evaporation method using calcium oxide (CaO). In other words, in this embodiment, an alkaline earth metal fluoride is used for the halide layer, and an alkaline earth metal oxide is used for the oxide layer. The device characteristics of the obtained organic EL device were measured. The results are shown in Table 1.

[0101] [Example 4]

The electron injection layer is made of scandium fluoride (ScF) for electron beam evaporation.

Three

An organic EL device was produced in the same manner as in Example 1 except that the film was formed to a thickness of 2 nm and the oxide layer was formed to a thickness of 5 nm by an electron beam evaporation method using barium oxide (BaO). That is, in this embodiment, fluoride is used for the halide layer, and an alkaline earth metal oxide is used for the oxide layer. And the element characteristic of the obtained organic EL element was measured. The results are shown in Table 1.

[Example 5]

The electron injection layer has a halide layer with a thickness of 2 nm formed by LiF using resistance heating vapor deposition, and the oxide layer is formed with an acid aluminum layer (Al 2 O 3) by electron beam evaporation to a thickness of 2 nm. Completion

twenty three

An organic EL device was produced in the same manner as in Example 1 except that the film was formed. That is, in this embodiment, an alkali metal fluoride is used for the halide layer and an oxide is used for the oxide layer. Then, the device characteristics of the obtained organic EL device were measured. The results are shown in Table 1.

[0103] [Table 1] Current density Luminance Luminance Electron injection layer

(m A / cm) c d / m) Example 1 10. 8 614 Example 2 8. 5 480 Example 3 9. 1 493 Example 4 6. 4 312 Example 5 4.4 4 185

From the results in Table 1 above, the current density and light emission luminance are remarkably increased by using an alkali metal fluoride for the halogen layer and an alkaline earth metal oxide for the oxide layer as in Example 1. I understand that it ’s high. In addition, by comparing Example 1 to Example 4 and Example 5, by using an alkali metal or alkaline earth metal oxide for the oxide layer, the current density and emission luminance can be further increased. It can be seen that it can be raised. Further, according to Example 1, Example 3, and Example 4, the use of an alkali metal or alkaline earth metal fluoride for the halide layer can increase the current density and the emission luminance. I understand that.

[Example 6]

Next, an example in which an organic EL element is manufactured using a material having transparent conductivity for the cathode will be described.

[0105] First, indium stannate (ITO), which is a transparent conductive film, is formed on a 25 mm square substrate to a thickness of 150 nm in a mixed atmosphere of oxygen and argon using a sputtering device. Formed. Next, using photolithography technology, ITO is patterned into stripes 2mm wide and 25mm long! / This was the anode.

[0106] Then, PEDOT-PSS was applied onto the anode by spin coating, and dried at 200 ° C for 10 minutes to form a hole transport layer. The film thickness of the hole transport layer is the concentration of the solution, The thickness was about 70 nm by controlling the number of rotations during spin coating. Next, a solution of the polyfluorene derivative was similarly applied to the hole transport layer by spin coating, and dried at 150 ° C. for 10 minutes to form a light emitting layer. The film thickness of the light emitting layer was set to about 70 nm by controlling the concentration of the solution and the number of rotations during spin coating.

[0107] Next, a cesium fluoride (CsF) film, which is a fluoride, is formed on the light-emitting layer by an electron beam evaporation apparatus so that the stripe is 2 mm wide and 25 mm long so as to be perpendicular to the anode stripe. It was formed with a film thickness. Next, a strontium oxide (SrO) film, which is an oxide, is striped in a 2 mm width and 25 mm length so that it has the same shape as the CsF on the CsF film, which is a halide layer, using an electron beam evaporation system. The film was formed to a thickness of 3 nm, and a laminated film of CsF (a non-oxide layer) and Sr o (an oxide layer) was used as an electron injection layer. That is, in this embodiment, an alkali metal fluoride is used for the halide layer, and an alkaline earth metal oxide is used for the oxide layer. Finally, ITO as the cathode was formed on the SrO thin film in the same shape as the electron injection layer with a thickness of 150 nm in a mixed atmosphere of oxygen and argon using a sputtering apparatus. As a result, an organic EL device having a light emitting surface of 2 mm × 2 mm was obtained. When this organic EL device was driven and the brightness at that time was measured, it was possible to obtain light emission of 510 cd / m ^{2 on} the anode side and 470 cdZm ² on the cathode side at 4.5 V. An EL device was obtained.

[0108] The organic EL device according to the present invention is provided between an anode, a cathode, an organic layer including at least an organic light emitting layer provided between the anode and the cathode, and the cathode and the organic layer. And an electron injection layer, wherein the anode, the organic layer, the halide layer, the oxide layer, and the cathode force are stacked in this order. By making the electron injection layer have the above structure, electrons are smoothly injected into the organic layer, and as a result, the driving voltage can be reduced. Furthermore, the electron injection layer in the present invention is composed of an acid compound and a halogen compound that hardly react with oxygen, whereby the electron injection layer can be made very stable. That is, the organic EL device is very stable. In addition, the oxide layer of the electron injection layer is preferably made of an alkali metal or alkaline earth metal oxide. Alkali metal or alkali metal earth oxides have a low work function, so that the efficiency of electron injection into the organic layer can be increased. Also electronic The halide layer of the injection layer is preferably composed of an alkali metal or alkaline earth metal halide. Alkali metal or alkaline earth metal halides lower the electron injection barrier height between the cathode and the organic layer. The halogenated material layer is preferably composed of a foodstuff. Fluoride also reduces the electron injection barrier height between the cathode and the organic layer. Further, by setting the thickness of the electron injection layer to 0.1 to 20 nm, it becomes possible to efficiently inject electrons into the organic layer. Further, in the structure of the electron injection layer of the organic EL device in the present invention, even when a transparent conductive oxide film is formed, the electron injection layer is very chemically stable against water and oxygen. Therefore, the stability of an organic EL device having a cathode made of a transparent conductive oxide film can be made extremely excellent.

[0109] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. Such embodiments are also included in the technical scope of the present invention. Industrial applicability

[0110] An organic EL device according to the present invention is provided between an anode, a cathode, an organic layer including at least an organic light emitting layer provided between the anode and the cathode, and the cathode and the organic layer. In addition, an electron injection layer including at least an oxide layer and a halide layer is provided, and the anode, the organic layer, the halide layer, the oxide layer, and the cathode force are laminated in this order.

[0111] Therefore, it is possible to realize an organic EL element with low power consumption and less element degradation even for a long time as compared with the conventional one.

Therefore, the organic EL device according to the present invention can be suitably applied to, for example, a display panel for displaying information.

Claims

The scope of the claims

[1] an anode,

A cathode,

An organic layer including at least an organic light emitting layer provided between the anode and the cathode; and an electron injection layer including at least an oxide layer and a halide layer provided between the cathode and the organic layer. Prepared,

An organic electoluminescence device, wherein the anode, the organic layer, the halide layer, the oxide layer, and the cathode are laminated in this order.

[2] The oxide layer according to claim 1, wherein the oxide layer is in contact with at least a part of the cathode, and Z or the halide layer is in contact with at least a part of the organic layer. Organic-elect mouth luminescence element.

[3] The organic electoluminescence device according to [1], wherein the halide layer and the oxide layer are in contact with each other.

[4] The organic electoluminescence device according to [1], wherein the material constituting the oxide layer is an alkali metal or alkaline earth metal oxide.

[5] The organic electoluminescence device according to [1], wherein the material constituting the halide layer is an alkali metal or alkaline earth metal halide.

[6] The organic electoluminescence device according to [1], wherein the material constituting the halide layer is a fluoride.

7. The organic electroluminescent mouth luminescence device according to claim 1, wherein the electron injection layer has a thickness in the range of 0.1 to 20 nm.

[8] The organic electroluminescent device according to [1], wherein the material constituting the cathode is a transparent conductive oxide.

[9] An organic electro- device comprising an anode, a cathode, an organic layer including at least an organic light emitting layer provided between the anode and the cathode, and an electron injection layer provided between the cathode and the organic layer. A method of manufacturing a luminance element,

A halide layer forming a halide layer on at least a part of the surface of the organic layer Forming process;

And an oxide layer forming step of forming an oxide layer on at least a part of the halide layer. A method for producing an organic electoluminescence device, comprising:

An organic electroluminescence display panel, comprising the organic electoluminescence device according to claim 1.