JP2009252792A - Organic luminescence element - Google Patents

Abstract

A highly efficient and long-life organic light-emitting device is provided more simply.
At least a pair of electrodes including an anode and a cathode and an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes, and the hole injection layer is a mixture of at least one layer. The layer 8 includes a mixed layer of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.
[Selection] Figure 2

Description

  The present invention relates to an organic light emitting device, and is particularly used for a display.

  Since the electroluminescent element is a self-luminous type, it has high visibility, excellent display performance, can respond at high speed, and can be thinned. Therefore, the electroluminescent element is attracting attention as a display element such as a flat panel display.

  Among them, an organic light emitting device (organic EL device) using an organic compound as a light emitter can be driven at a lower voltage than an inorganic EL device, and can easily be increased in area, and by selecting an appropriate light emitting material. In addition, it has characteristics such that a desired emission color can be easily obtained. For this reason, organic light-emitting elements are being actively developed as next-generation displays.

  There are two types of EL elements using organic light emitters: a type in which a low molecular weight compound is formed by a dry process such as a vacuum evaporation method, and a type in which an element is formed by a so-called wet process such as a spin coating method, a casting method, or an ink jet method. is there.

The organic EL element produced by the wet process (hereinafter, coating type organic EL element) is compared with the organic light emitting element produced by the dry process.
(I) Low cost (ii) Easy large area (iii) Advantages such as excellent controllability of a small amount of doping can be mentioned.

  FIG. 11 shows a general configuration of the coating type organic EL element. A hole injection layer 102 is provided on an anode 101 formed on a substrate 100, an organic light emitting layer 103 is formed on the hole injection layer 102, and an electron injection layer 104 and a cathode 105 are formed thereon.

  Generally, PEDOT: PSS (mixture of polythiophene and polystyrene sulfonic acid) shown in FIG. 12 is used for the hole injection layer and is formed by spin coating or the like. Since PEDOT: PSS is soluble in water and insoluble in nonpolar solvents, the PEDOT: PSS film does not elute even when an organic light emitting layer dissolved in a nonpolar solvent is formed by a coating process. Therefore, it is considered a suitable hole injection material for the coating type organic EL.

  The organic light emitting layer 103 is formed by spin coating or the like using polyphenylene vinylene, polyfluorene, polyvinyl carbazole, or a derivative thereof on the PEDOT: PSS. Then, an electron injection layer such as lithium fluoride and a metal electrode as a cathode are formed on the light emitting layer by vacuum deposition to complete the device.

  As described above, the coating type organic EL has an excellent feature that it can be produced by a simple process, and is expected to be applied to various uses. However, these two points are problems to be improved, in that a sufficiently large light emission intensity cannot be obtained and a lifetime is not sufficient.

  Various speculations have been made about the cause of the decrease in the emission intensity, and the deterioration of PEDOT: PSS is considered as one of the main causes. This is because S atoms and H atoms derived from the sulfone group and ionic components such as Na contained as impurities diffuse into the light emitting layer by energization, causing an undesirable effect. Moreover, it is thought that one of the causes is that the conductivity of PEDOT: PSS deteriorates due to electrons flowing into PEDOT: PSS.

  In view of the above problems, an attempt has been made to provide an organosilicon compound as an electron blocking layer between PEDOT: PSS and the anode (Patent Document 1). In Patent Document 1, an organic silicon compound having a Si—O bond is formed on PEDOT: PSS by spin coating, and a light emitting layer of fluorene derivative, calcium, and silver are sequentially formed thereon, thereby improving efficiency and lengthening. Realizes longevity. The improvement in efficiency is considered to be because the recombination probability of electrons and holes is increased by blocking the electrons that flow from the light emitting layer to PEDOT: PSS. On the other hand, the improvement of the lifetime is considered to be due to the fact that the organosilicon compound blocked ion diffusion from PEDOT: PSS.

JP-A-2005-302443

  However, in the method disclosed in Patent Document 1, since an insulating siloxane compound is interposed in the PEDOT: PSS layer and the organic light emitting layer, there is a concern about an increase in driving voltage, and a decrease in power efficiency. It is conceivable that the lifetime will be shortened due to an increase in driving voltage.

  The present invention has been made in view of the above problems, and an object thereof is to provide a highly efficient and long-life organic light-emitting device more easily.

  Moreover, the objective of this invention is providing the display apparatus or display using the said organic EL element.

  The organic light-emitting device of the present invention comprises at least a pair of electrodes consisting of an anode and a cathode, and an organic light-emitting layer and a hole injection layer sandwiched between the pair of electrodes, and the hole injection layer is at least one mixed layer The mixed layer is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.

  Moreover, in this invention, as described in Claim 2, the film thickness of the said mixed layer is the range of 20-80 nm, It is characterized by the above-mentioned.

  In the present invention, as described in claim 3, the hole injection layer includes at least one layer made of only a hole injection material.

  Moreover, this invention relates to the display characterized by having the said organic light emitting element as described in Claims 1-5, and the drive circuit of this element in multiple numbers.

  The present invention also relates to a panel module comprising an interface between the display according to claim 5 and an external device.

  The present invention also relates to a portable device comprising the display according to claim 6.

  In the present invention, at least a pair of electrodes including an anode and a cathode, and an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes are included, and the hole injection layer includes at least one mixed layer. And the mixed layer is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound. The mixed layer is formed by coating and forming a solution in which at least the water-soluble conductive polymer and the siloxane compound are dissolved or dispersed.

  According to a first aspect of the present invention, the organic light emitting device of the present invention comprises at least a pair of electrodes composed of an anode and a cathode, an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes, and the hole The injection layer includes at least one mixed layer. The mixed layer is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.

  In many coating type organic EL elements, when a transparent electrode such as ITO is formed on a substrate and used as an anode, a hole injection layer is formed between the transparent electrode and the organic light emitting layer. Usually, a nonpolar solvent such as toluene or xylene is used to form the organic light emitting layer. Therefore, the material used for the hole injection layer must be selected from materials that do not dissolve in nonpolar solvents. Therefore, most of the hole injection materials used for the coating type organic EL element are water-soluble conductive polymers represented by the above-mentioned PEDOT: PSS.

  However, since the water-soluble conductive polymer is dispersed or dissolved in an aqueous solvent, impurity ions such as alkali metals and alkaline earth metals are easily contained. Further, in the case of having a functional group having an acidic component such as a sulfone group, proto and sulfur ions may be contained in the membrane. For this reason, there is a concern that these ionic components may diffuse into the organic light emitting layer and adversely affect the device lifetime.

  It is also conceivable that PEDOT: PSS deteriorates due to electrons flowing into PEDOT: PSS, resulting in an increase in driving voltage and a reduction in light emission efficiency.

  In the present invention, a mixture of a water-soluble conductive polymer and a siloxane compound or a cross-linked product of the water-soluble conductive polymer and the siloxane compound is used for the hole injection layer.

  Since most siloxane compounds dissolve in polar solvents such as water and bipolar solvents such as alcohol, siloxane compounds can be mixed with the water-soluble conductive polymer. Siloxane compounds are chemically and thermally stable materials. Therefore, by mixing the siloxane compound with the water-soluble conductive polymer, diffusion of ions can be prevented, the chemical stability of the hole injection layer can be increased, and the electron blocking property is enhanced. It becomes possible to improve the lifetime of the. In Patent Document 3, a siloxane compound is interposed between the hole injection layer and the organic light emitting layer to increase the efficiency and life of the device. However, since the insulating siloxane compound is present in such a configuration, there is a concern that the voltage of the device is increased, and there is a concern that the power efficiency is lowered and the device life is shortened.

  In the present invention, since the siloxane compound is mixed with the water-soluble conductive polymer, the stability of the hole injection layer can be increased with little increase in driving voltage, and the life can be extended.

  Moreover, in this invention, as shown in Claim 2, the film thickness of the said mixed layer is 20-80 nm, It is characterized by the above-mentioned. If the mixed layer is too thin, the optical characteristics cannot be fully utilized. Further, since the film quality deteriorates, the leakage current of the element increases, which may lead to a reduction in efficiency and life. On the other hand, if the mixed layer is made too thick, the above problem can be solved, but the power emission efficiency is reduced due to an increase in driving voltage. For the above reasons, in the present invention, the thickness of the mixed layer is preferably 20 to 80 nm so that both the above problems do not occur remarkably.

  According to the present invention, as shown in claim 3, the hole injection layer includes at least one layer made of only a hole injection material. Since the mixed layer contains a siloxane compound which is an insulator, the resistance of the film is increased and the driving voltage of the element is increased. Further, when the mixed layer is formed directly on the anode, there is a risk that the hole injectability is deteriorated by the presence of the siloxane compound. Therefore, in the present invention, by providing the hole injection layer with a layer made of only the hole injection material, the resistance of the hole injection layer can be lowered and the hole injection property can be improved.

  According to a fourth aspect of the present invention, there is provided a display comprising a plurality of the organic light emitting elements and a drive circuit for the elements.

  Furthermore, according to the present invention, as shown in claim 5, a panel module comprising an interface between the display and an external device.

  Furthermore, the present invention is a portable device in which the display is mounted as shown in claim 6.

  Further, according to a seventh aspect of the present invention, there is provided a method for forming the mixed layer of the organic light-emitting device according to the present invention, wherein the hole injection layer is formed by using a solution in which a water-soluble conductive polymer and a siloxane compound are mixed at least. It is characterized by coating film formation. In the present invention, unlike in Patent Document 3, a mixed layer is separately formed. Therefore, since the number of coating processes can be reduced, the lifetime and efficiency of the organic light emitting device can be easily increased.

  The organic EL device of the present invention comprises at least a pair of electrodes composed of an anode and a cathode, and an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes, and the hole injection layer is at least one mixed layer. Is included. The mixed layer is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.

  Since most siloxane compounds dissolve in polar solvents such as water and bipolar solvents such as alcohol, siloxane compounds can be mixed with the water-soluble conductive polymer. Siloxane compounds are chemically and thermally stable materials. With the above structure, ion diffusion can be prevented and the stability of the hole injection layer can be increased, so that the lifetime of the element can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited thereby.

  FIG. 1 shows an example of an embodiment of the present invention. The organic EL element shown in FIG. 1 includes a substrate 1, an anode 2, a hole injection layer 3, an organic light emitting layer 4, an electron injection layer 5, and a cathode 6.

  The substrate 1 is not particularly limited, such as glass, ceramic, compound, metal, plastic, etc. However, in the case of a bottom emission type element configuration, a transparent substrate such as glass is used. On the other hand, in the case of a top emission type element, a metal substrate is used to prevent light leakage to the lower part of the substrate, or a cathode material such as Ag is formed on a glass substrate or the like to form a mirror structure. Further, it is also possible to control the colored light by adding a color filter film, a fluorescent color conversion filter film, a dielectric reflection film, or the like to the substrate. It is also possible to form a thin film transistor on a substrate and connect it to produce an element.

  The anode 2 preferably has a work function as large as possible, for example, gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, tungsten, chromium or the like, or an alloy thereof, tin oxide, zinc oxide Metal oxides such as indium oxide, indium tin oxide, and zinc indium oxide, and halides such as CuI can be used. In addition, conductive polymers such as polyaniline, polypyrrole, polythiophene, and polyphenylene sulfide can also be used. These electrode materials can be used alone or in combination. Further, the anode may have a single layer structure or a multilayer structure.

  The hole injection layer 3 may include at least one layer (mixed layer) in which at least a water-soluble conductive polymer and a siloxane compound are mixed.

  Examples of the water-soluble conductive polymer include a conductive polymer having a sulfonic acid group, and examples thereof include PEDOT: PSS and polyaniline sulfonic acid.

  On the other hand, the siloxane compound may be any material as long as it has a Si—O bond, such as dimethylpolysiloxane, diphenylpolysiloxane, fluoropolysiloxane, styrylpolysiloxane, aminopolysiloxane, mercaptopolysiloxane, epoxypolysiloxane, etc. Various organic functional groups can be used by appropriately changing them, and a single composition polysiloxane may be used, or a plurality of polysiloxanes may be mixed and used. Further, the structure of the siloxane compound is not particularly limited, such as a structure in which an organic functional group is introduced into a side chain or a structure in which an organic functional group is introduced into a terminal. Further, the siloxane compound of the present invention can be used by curing with various external energies such as heat curing and ultraviolet curing. In the present invention, it is insolubilized in an organic solvent by curing, so that an organic light emitting layer can be laminated on the electron block layer by a coating process.

  In the present invention, the silane compound may be produced by dehydrating and condensing the silane compound. In this case, the silane compound used in the present invention is not particularly limited. For example, tetraethoxylane, tetramethoxysilane, methyltrichlorosilane, methyltribromosilane, methyltriisopropoxysilane, ethyltrichlorosilane, ethyl Illustrate tribromosilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltridiphenyldimethoxysilane, etc. Can do. In addition, other examples include partial hydrolysates of silane compounds and mixtures thereof.

  Further, if the mixed layer is made too thin, the leakage current of the element increases due to deterioration of the film quality, which may lead to a reduction in efficiency and life. On the other hand, if the mixed layer is made too thick, the above problem is solved, but the luminous efficiency is reduced due to an increase in driving voltage. For the above reasons, in the present invention, the thickness of the mixed layer is preferably 20 nm to 80 nm so that both the above problems do not occur remarkably. The content of the siloxane compound is preferably 10 to 70% by weight with respect to the mass of the entire film. This range is a range in which the stability of the siloxane compound is effectively used and the driving voltage is not significantly increased.

  Further, the hole injection layer of the present invention may be formed by applying the mixed layer 8 on the layer 7 formed only of the hole injection material as shown in FIG. good. With such a configuration, it is possible to reduce the resistance of the hole injection layer and improve the hole injection property. The hole injection material shown here may be any material that conducts holes. For example, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazoles, oxadiazoles, triazoles, imidazoles in addition to the water-soluble conductive polymers described above. Examples thereof include imidazolone, pyrazoline, tetrahydroimidazole, polyarylalkane, butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, and derivatives thereof, polyvinylcarbazole, polysilane, and the like.

  The organic light emitting layer 4 may be any organic compound that performs organic electroluminescence. For example, if it is a low molecular weight system, anthracene, naphthalene, pyrene, tetracene, coronene, perylene, phthaloperylene, naphthaloperylene, diphenylbutadiene, tetraphenylbutadiene , Coumarin, oxadiazole, bisbenzoxazoline, bisstyryl, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, pyran, quinacridone, rubrene and their derivatives, and iridium-phenylpyridine complex Illustrative phosphorescent metal complexes are exemplified. Moreover, if it is a high molecular type, a polyvinyl carbazole, polyphenylene vinylene, polyfluorene, and those derivatives can be illustrated.

  Further, the light emitting layer may be a host-guest system, and the combination may be a combination of low molecules, a combination of a polymer and a low molecule, or a combination of polymers. There may be.

  The light emitting layer is formed using a vacuum deposition method or a coating method such as a spin coating / ink jet method.

The electron injection layer 5 may be anything as long as it has electron conductivity. For example, as exemplified by LiF, Cs ₂ CO ₃ , CaO, etc., fluorides, carbonate compounds, and oxides of alkali metals and alkaline earth metals. And the like. In addition to the above materials, organic compounds having electron conductivity may be used. For example, quinoline derivatives such as aluminum quinoline complex (Alq), oxadiazole derivatives, triazole derivatives, phenanthroline derivatives, perylene derivatives, pyridine derivatives, Examples include pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, and nitro-substituted fluorene derivatives.

  The cathode material 6 preferably has a small work function. For example, lithium, sodium, potassium, calcium, magnesium, aluminum, indium, ruthenium, titanium, manganese, yttrium, silver, lead, tin, chromium, etc. -It can be used as a plurality of alloys such as indium, sodium-potassium, magnesium-silver, aluminum-lithium, aluminum-magnesium, magnesium-indium. A metal oxide such as indium tin oxide can also be used. These electrode materials can be used alone or in combination. Further, the cathode may have a single layer structure or a multilayer structure.

  Moreover, it is desirable that at least one of the anode and the cathode is transparent or translucent.

  In the present invention, in addition to the above structure, at least one of an electron transport layer and a hole transport layer can be provided. The electron transport layer may be anything as long as it transports electrons. For example, an electron transport material as exemplified in the electron injection layer can be used. The hole transport layer may be any material that transports holes, such as phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, oxazole, oxadiazole, triazole, imidazole, imidazolone, pyrazoline, tetrahydroimidazole, polyarylalkanes. , Butadiene, benzidine type triphenylamine, styrylamine type triphenylamine, diamine type triphenylamine, etc. and their derivatives, polyvinyl carbazole, polysilane, conductive polymer, and other polymer materials. It is not something.

  In addition to the above-described configuration, the present invention may have a configuration in which the electron blocking layer 9 is formed between the organic light emitting layer 4 and the hole injection layer 3 as shown in FIG. With such a configuration, electrons leaking into the hole injection layer can be blocked by the layer, and the recombination probability of electrons and holes can be increased, so that the efficiency of the device can be increased. The electron block material may be any insulating or hole transporting material. Examples thereof include insulating materials such as the above-described siloxane compounds and hole transporting materials such as polyvinyl carbazole.

  In the present invention, a protective layer or a sealing layer can be provided on the prepared element for the purpose of preventing contact with oxygen or moisture. Examples of the protective layer include diamond thin films, inorganic material films such as metal oxides and metal nitrides, polymer films such as fluorine resin, polyparaxylene, polyethylene, silicone resin, and polystyrene resin, or photocurable resins. Further, it is possible to cover glass, a gas-impermeable film, a metal, etc., and to package the element itself with an appropriate sealing resin.

  FIG. 4 is a schematic cross-sectional view showing the arrangement of the organic EL elements on the substrate, the circuits arranged outside thereof, and the data lines.

  The circuit includes a TFT and a storage capacitor.

  The organic light emitting device has an anode, a cathode, and an organic compound layer disposed therebetween.

  In addition to these, the organic EL element may have, for example, an auxiliary electrode. In this figure, only one organic EL element is shown. However, when a display is constructed, a plurality of organic EL elements are two-dimensionally arranged as shown in FIG.

  The organic compound according to this embodiment is included in this organic compound layer, and the organic compound layer can be formed by various methods. For example, a spin coating method, an ink jet method, a nozzle printing method, a transfer method, or the like can be used.

  FIG. 6 shows details of the configuration of the circuit shown in FIG. The circuit shown in FIG. 6 has a typical circuit configuration called a current programming method. The circuit of the present invention is not limited to this.

  The circuit includes a drive transistor T1, a switching transistor T2, a storage capacitor Ch, and an organic EL element. Since the circuit configuration is well known, detailed description of the operation is omitted.

  This organic EL element can be used as an exposure light source of a display, an illuminating device, or an electrophotographic image forming apparatus using one light emitting point.

  The case where the said organic EL element is utilized for a display is demonstrated.

  FIG. 5 schematically shows a state in which a plurality of organic EL elements and circuits shown in FIGS. 4 and 6 are arranged as a pixel in a two-dimensional manner on the same plane, that is, arranged in a matrix.

  This pixel is connected to a gate driver and a source driver through a wiring, and enters a light emitting state or a non-light emitting state when a driving pulse is supplied.

  A region where a plurality of such organic EL elements are arranged in the same plane as pixels in the in-plane direction is a display region of the display. That is, the organic EL element according to the present embodiment can be used for a display area of a display.

  The display may take any form as long as it is a display device for a television (see the right in FIG. 7), a PC, or a device having an image display portion. For example, a portable display device may be used. Or the display which concerns on this embodiment can be used for the display part of electronic imaging devices, such as a digital camera, and a mobile telephone (refer FIG. 7 left).

  FIG. 8 shows a configuration in which the display shown in FIG. 5 is made into a panel module. The panel module means a configuration in which components necessary for connection to an external device such as an interface driver and a connection terminal are integrated in a casing in addition to the configuration shown in FIG.

  Examples of the present invention will be described below.

<Example 1>
The organic light emitting device shown in FIG. 1 was produced. At the time of production, the following materials were used as constituent members.
Substrate 1: Glass substrate Anode 2: ITO
Hole injection layer 3: PEDOT: PSS (Startron Baytron-P VP A
L4083)
Siloxane polymer (manufactured by Honeywell, ACCUGLASS 111)
Organic light emitting layer 4: oligofluorene compound (host) shown in FIG.
Ir (C8piq) ₃ (guest) shown in FIG.
Electron injection layer 5: Cs ₂ CO ₃
Cathode 6: Al

  The manufacturing process of the element is shown below. First, an ITO film serving as an anode is formed on a glass substrate by sputtering so as to have a film thickness of about 100 nm. Next, a hole injection layer was formed by spin coating. The solution used for forming the hole injection layer was a mixed solution of the PEDOT: PSS solution and a solution obtained by diluting the siloxane polymer solution to 1/3 with isopropyl alcohol. What was prepared so that the mixing ratio of PEDOT: PSS and a siloxane polymer solution might be set to 7: 3 by volume ratio was used. The film thickness was 50 nm.

The organic light emitting layer 5 was formed by spin-coating at 1000 rpm a solution in which the oligofluorene compound shown in FIG. 9 and Ir (C8piq) ₃ shown in FIG. 10 were dissolved in a toluene solvent. Ir (C8piq) ₃ has a doping concentration of 1.0 wt% with respect to the total weight of the organic light emitting layer. The film thickness at this time is about 100 nm. Next, Cs ₂ CO ₃ which is the electron injection layer 6 is formed by resistance heating vapor deposition so as to have a film thickness of 2.4 nm. Next, Al which is the cathode 7 is formed to a thickness of 80 nm by resistance heating vapor deposition. Finally, a protective glass plate is placed in a nitrogen atmosphere and sealed with an acrylic resin adhesive. When a direct current voltage of 5.6 V is applied to the device manufactured by the above method with the ITO electrode as the positive electrode and the Al electrode as the negative electrode, a current flows through the device at a current density of about 100 mA / cm ² , and about 2760 cd / m ^2. A red light emission was observed at a luminance of. The chromaticity is NTSC (X, Y) = (0.67, 0.32).

<Example 2>
In the element configuration of Example 1, the hole injection layer has a film thickness of 10 nm.

<Example 3>
In the element configuration of Example 1, the element structure is such that the thickness of the hole injection layer is 100 nm.

<Example 4>
In the element configuration of Example 1, a PEDOT: PSS layer having a thickness of 10 nm is provided between the ITO electrode and the hole injection layer, and the thickness of the mixed layer is set to 20 nm.

<Example 5>
In the device configuration of Example 1, the device configuration was such that the mixing ratio of PEDOT: PSS and siloxane polymer was 5: 5 (volume ratio).

<Comparative Example 1>
This is an example in which only PEDOT: PSS is used for the hole injection layer in the element configuration of Example 1.

<Comparative example 2>
In the element configuration of Example 1, PEDOT: PSS is used for the hole injection layer, and further, a layer of only a siloxane polymer (manufactured by Honeywell, ACCUGLASS 111) is formed on the hole injection layer, and this is used as an electron block layer.

  In Example 1, compared with the comparative example 1, the improvement of efficiency and a lifetime was able to be confirmed by mixing a siloxane compound with PEDOT: PSS. This seems to be because the diffusion rate of ions into the light emitting layer could be slowed, the electron blocking property was improved, and the chemical stability of the hole injection layer was improved.

  Moreover, in Example 1, the fall of the drive voltage was able to be confirmed compared with the comparative example 2. In Comparative Example 2, it is considered that the electrical resistance value of the element was increased because of the presence of a layer containing only the siloxane polymer.

  In Example 2, the light emission characteristics of the device became unstable by reducing the film thickness of the hole injection layer, and the efficiency and lifetime were inferior to those of the other examples.

  On the other hand, in Example 3, since the thickness of the hole injection layer was increased, the drive voltage was increased, and the element lifetime was also shorter than that in Example 1.

  In Example 4, it was confirmed that the drive voltage was lowered while the efficiency was maintained at substantially the same value by providing the layer of only PEDOT: PSS. This is presumably because the electric resistance value of the hole injection layer could be reduced by reducing the thickness of the mixed layer and providing a layer of only PEDOT: PSS.

  Moreover, in Example 5, the improvement in efficiency was confirmed by increasing the mixing amount of the siloxane polymer. This seems to be because the electron blocking property of the hole injection layer was improved because the amount of the siloxane polymer was increased. On the other hand, a slight increase in drive voltage was also confirmed. This is presumably because the electrical resistance value of the hole injection layer was increased due to an increase in the content of the siloxane polymer.

  According to the present invention, an organic light emitting device comprises at least a pair of electrodes composed of an anode and a cathode, an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes, and the hole injection layer is at least one layer. Contains a mixed layer of. The mixed layer is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.

  In addition, a display, a panel module, or a portable device including the organic light emitting element can be provided.

  Furthermore, in this invention, the manufacturing method which can manufacture a highly efficient and long-life organic EL element simply can be provided.

It is a figure which shows an example of the organic light emitting element in this invention. It is a figure which shows an example of the organic light emitting element in this invention. It is a figure which shows an example of the organic light emitting element in this invention. 1 is a schematic cross section showing an organic EL element according to an embodiment of the present invention and a circuit and wiring for driving the organic EL element. It is a schematic diagram which shows the state which has arrange | positioned an organic EL element and a circuit in 1-pixel matrix form, and comprised the display. It is a figure which shows the detail of a circuit. It is a figure which shows an example of the television and portable apparatus using the display of this invention. It is a schematic diagram which shows the structure which made the display module of this invention into the panel module. It is a structural diagram of the oligofluorene compound used as a host material of the organic light emitting layer of the Example of this invention. FIG. _{3 is} a structural diagram of Ir (C8piq) ₃ used as a guest material for an organic light emitting layer in an example of the present invention. It is a figure which shows an example of the conventional organic light emitting element. It is a structural diagram of PEDOT: PSS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Anode 3 Hole injection layer 4 Organic light emitting layer 5 Electron injection layer 6 Cathode 7 Layer formed only with hole injection material 8 Mixed layer 9 Electron block layer 100 Substrate 101 Anode 102 Hole injection layer 103 Organic light emitting layer 104 Electron injection layer 105 Cathode

Claims (7)

  At least a pair of electrodes composed of an anode and a cathode, and an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes. The hole injection layer includes at least one mixed layer, and the mixed layer Is a mixture of a water-soluble conductive polymer and a siloxane compound, or a cross-linked product of the water-soluble conductive polymer and the siloxane compound.   The organic light-emitting device according to claim 1, wherein the mixed layer has a thickness in a range of 20 nm to 80 nm.   3. The organic light emitting device according to claim 1, wherein the hole injection layer includes at least one layer made of only a hole injection material. 4.   A display comprising the organic light-emitting device according to claim 1 and a plurality of drive circuits for the device.   A panel module comprising an interface between the display according to claim 6 and an external device.   A portable apparatus, comprising the display according to claim 6.   At least a pair of electrodes composed of an anode and a cathode, and an organic light emitting layer and a hole injection layer sandwiched between the pair of electrodes. The hole injection layer includes at least one mixed layer, and the mixed layer Is a mixture of a water-soluble conductive polymer and a siloxane compound, or a crosslinked product of the water-soluble conductive polymer and the siloxane compound, wherein the mixed layer comprises: A method for producing an organic light-emitting element, wherein the organic light-emitting element is formed by coating a film in which at least the water-soluble conductive polymer and the siloxane compound are dissolved or dispersed.

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