WO2022255178A1 - 電荷発生構造及び有機el素子 - Google Patents
電荷発生構造及び有機el素子 Download PDFInfo
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- WO2022255178A1 WO2022255178A1 PCT/JP2022/021333 JP2022021333W WO2022255178A1 WO 2022255178 A1 WO2022255178 A1 WO 2022255178A1 JP 2022021333 W JP2022021333 W JP 2022021333W WO 2022255178 A1 WO2022255178 A1 WO 2022255178A1
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- transfer material
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- charge transport
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- 239000000463 material Substances 0.000 claims abstract description 146
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- 229910052761 rare earth metal Inorganic materials 0.000 claims description 8
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- PWYVVBKROXXHEB-UHFFFAOYSA-M trimethyl-[3-(1-methyl-2,3,4,5-tetraphenylsilol-1-yl)propyl]azanium;iodide Chemical compound [I-].C[N+](C)(C)CCC[Si]1(C)C(C=2C=CC=CC=2)=C(C=2C=CC=CC=2)C(C=2C=CC=CC=2)=C1C1=CC=CC=C1 PWYVVBKROXXHEB-UHFFFAOYSA-M 0.000 claims description 4
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- 230000008021 deposition Effects 0.000 description 4
- GNTDGMZSJNCJKK-UHFFFAOYSA-N divanadium pentaoxide Chemical compound O=[V](=O)O[V](=O)=O GNTDGMZSJNCJKK-UHFFFAOYSA-N 0.000 description 4
- 239000002019 doping agent Substances 0.000 description 4
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- 238000004770 highest occupied molecular orbital Methods 0.000 description 3
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- 239000010703 silicon Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- LWTIGYSPAXKMDG-UHFFFAOYSA-N 2,3-dihydro-1h-imidazole Chemical class C1NC=CN1 LWTIGYSPAXKMDG-UHFFFAOYSA-N 0.000 description 2
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- 150000004706 metal oxides Chemical class 0.000 description 2
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- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910006404 SnO 2 Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 1
- 229910001413 alkali metal ion Inorganic materials 0.000 description 1
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- 125000002091 cationic group Chemical group 0.000 description 1
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- 238000002955 isolation Methods 0.000 description 1
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- VSZWPYCFIRKVQL-UHFFFAOYSA-N selanylidenegallium;selenium Chemical compound [Se].[Se]=[Ga].[Se]=[Ga] VSZWPYCFIRKVQL-UHFFFAOYSA-N 0.000 description 1
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- 238000004528 spin coating Methods 0.000 description 1
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- 238000002230 thermal chemical vapour deposition Methods 0.000 description 1
- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
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- 238000007738 vacuum evaporation Methods 0.000 description 1
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- 239000011364 vaporized material Substances 0.000 description 1
- YVTHLONGBIQYBO-UHFFFAOYSA-N zinc indium(3+) oxygen(2-) Chemical compound [O--].[Zn++].[In+3] YVTHLONGBIQYBO-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/14—Carrier transporting layers
- H10K50/16—Electron transporting layers
- H10K50/166—Electron transporting layers comprising a multilayered structure
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B33/00—Electroluminescent light sources
- H05B33/12—Light sources with substantially two-dimensional radiating surfaces
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/19—Tandem OLEDs
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
- H10K85/30—Coordination compounds
-
- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
- H10K50/00—Organic light-emitting devices
- H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
- H10K50/14—Carrier transporting layers
- H10K50/16—Electron transporting layers
Definitions
- the present invention relates to charge generation structures.
- the present invention also relates to an organic electroluminescent element (hereinafter also referred to as an organic EL element) including the charge generation structure, which is provided with a plurality of light emitting units.
- an organic electroluminescent element hereinafter also referred to as an organic EL element
- An organic EL element is a semiconductor element that converts electrical energy into light energy, and in recent years, research has been actively conducted, and practical use is progressing.
- the driving voltage of the organic EL element has been significantly lowered and the luminous efficiency has been enhanced by improving the organic material constituting the element.
- Patent Document 1 proposes a method of increasing the brightness of the element by stacking a plurality of light emitting units of the organic EL element and connecting them in series.
- Patent Document 2 describes a laminated organic EL element in which electrically insulating connection units containing metal oxides such as vanadium pentoxide (V 2 O 5 ) are arranged between a plurality of light emitting units.
- Patent Document 3 proposes using a connection unit using molybdenum trioxide instead of vanadium pentoxide.
- connection unit In an organic EL device in which a connection unit is arranged between such light emitting units, when an electric field is applied, the connection unit causes holes that can be injected into the hole transport layer arranged on the cathode side and holes that can be injected into the hole transport layer arranged on the anode side. It simultaneously creates electrons that can be injected into the electron transport layer. Therefore, the plurality of light emitting units behave as if they are connected in series via the connection unit.
- MPE Multi-Photon Emission
- Patent Document 2 discloses the use of a radical anion-containing layer composed of Alq:Liq/Al as a layer on the anode side of a connection unit.
- a radical anion-containing layer composed of Alq:Liq/Al
- Li ions in Liq are reduced by a thermally reducible metal such as Al, which acts as a radical anion generating means. Therefore, it is understood that an electron-transporting organic substance such as Alq exists in a radical anion state and generates electrons that can be injected into the electron-transporting layer.
- connection unit includes a charge generation structure that generates electrons and/or holes as movable charges.
- JP-A-11-329748 Japanese Patent Application Laid-Open No. 2003-272860 JP-A-2006-24791
- a charge generating structure included in a conventional connection unit includes, for example, a layer in which an electron transporting material is used as a host material and an electron donating material is doped into the host material, but the physical properties of the structure vary greatly depending on the composition ratio of the doping material. . Therefore, the charge generating structure is likely to cause the above-mentioned instability of the connection unit. In order to prevent this, when forming a layer doped with an electron-donating material, precise control is required so that the composition ratio does not collapse. has a problem of losing
- the inventors of the present invention have found that the charge generation structure having the following configuration is highly efficient, highly stable, and highly reliable in terms of charge generation, and completed the present invention. came to.
- one aspect of the present invention has a plurality of charge transport layers and a charge transfer material layer, and the charge transfer material layer is sandwiched between two charge transport layers so that both surfaces are in contact with each other.
- the charge generation structure wherein the charge transport layer contains a charge transport material, the charge transfer material layer contains only a charge transfer material, and has an average thickness of 0.05 nm or more and 2.0 nm or less. be.
- This aspect is a charge generating structure comprising a charge transfer material layer sandwiched between two charge transport layers so that both sides thereof are in contact with each other, the charge transport layer comprising a charge transport material, and the charge It relates to a charge generation structure in which the transfer material layer contains only the charge transfer material and has an average film thickness of 0.05 nm or more and 2.0 nm or less.
- the charge transfer material is uniformly present in the film plane, and charge transfer can be effectively performed in the film thickness direction, resulting in a charge generating structure with excellent characteristics and high reliability.
- This aspect is a charge generating structure having a multilayer structure of a charge transport layer/a charge transfer material layer containing only a charge transfer material/a charge transport layer.
- One of the characteristics is that a "charge transfer material layer containing only a charge transfer material" is used. According to this aspect, it can be formed by a process of vapor-depositing only the charge transfer material without co-deposition for doping.
- a charge generating structure can be formed. That is, using a gas flow deposition apparatus that performs such gas flow deposition, part of the film formation process is not gas flow deposition but deposition based on the arrival of the material vapor in a vacuum atmosphere due to the mean free path. It is one of the features of the present invention that it is possible to Also, the charge generation structure of this aspect is preferably manufactured by using this vapor deposition method.
- the average layer thickness of the charge transfer material layer is as thin as 0.05 nm or more and 2.0 nm or less. Since the transportability of the transport layer is less likely to be hindered, a charge generation structure with higher performance can be constructed.
- each layer can be managed only by the film thickness. Therefore, it can be formed by a highly productive manufacturing method that can unify control items and reduce material loss that occurs during co-evaporation.
- a device including the charge generation structure of this aspect such as an organic EL device, has high performance, high reliability, and low cost.
- the present aspect has a structure containing a dopant, which is thought to exhibit no give-and-receive property unless it is co-deposited and doped, as a dopant monolayer having a specific structure. It can be said that this aspect is the result of discovering that such a structure enables effective charge generation.
- the charge generation structure of this aspect can be formed by single-layer film formation of each material, eliminating the rate matching process required during co-evaporation.
- the charge generation structure of this aspect has improved productivity compared with the conventional one, and can be produced at a low cost corresponding to the materials consumed in the rate matching process.
- the charge generating structure of this aspect can be formed using, for example, a gas carrier film forming apparatus.
- a preferred embodiment has at least two charge transfer material layers, and among the plurality of charge transport layers, an intermediate charge transport layer sandwiched between the two charge transfer material layers so that both surfaces thereof are in contact with each other. and the intermediate charge transport layer contains only the charge transport material and has an average thickness of 0.25 nm or more and 4 nm or less.
- This aspect includes, as an intermediate charge transport layer, a charge transport layer sandwiched between the two charge transfer material layers so that both surfaces are in contact with each other. This is related to the fact that the film thickness is 0.25 nm or more and 4 nm or less.
- the structure includes at least two charge transfer material layers and a thin intermediate charge transport layer sandwiched between the charge transfer material layers. That is, this aspect has a structure in which the charge transfer material is periodically dispersed. Therefore, the charge transfer action of the charge transfer material layer is effectively exerted, resulting in a charge generation structure with superior characteristics, high reliability and high performance.
- a preferred aspect includes 2 or more and 7 or less layers of the intermediate charge transport layer.
- the charge transfer action of the charge transfer material layer is more effectively exhibited, resulting in a charge generating structure with even higher performance.
- the charge transport material is preferably an electron transport material.
- the electron transport material is preferably one or more selected from the group consisting of quinolinolato-based metal complexes, anthracene-based compounds, oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, and silole-based compounds.
- the charge transfer material is preferably an electron donating material.
- the electron donating material is one or more selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, compounds of these metals, phthalocyanine complexes having these metals as central metals, and dihydroimidazole compounds. is preferred.
- the charge-transporting material is an electron-transporting material
- the electron-transporting material is selected from quinolinolato-based metal complexes, anthracene-based compounds, oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, and silole-based compounds.
- the charge transfer material is an electron donating material, and the electron donating material is an alkali metal, an alkaline earth metal, a rare earth metal, a compound of these metals, or a compound of these metals. It is one or more selected from the group consisting of a phthalocyanine complex having a metal as a central metal and a dihydroimidazole compound.
- the charge transfer action of the charge transfer material layer is exhibited more effectively.
- the charge generating structure of this aspect can A repeating structure of transport material layer/electron-donating metal layer/electron-transporting material layer/.../electron-donating metal layer/electron-transporting material layer is preferable.
- Such a charge generation structure is preferably provided on the anode side of a connection unit, which will be described later, in an organic EL element, for example.
- the charge transfer material is ytterbium (Yb).
- the charge transfer action of the charge transfer material layer is exhibited more effectively.
- One aspect of the present invention is an organic EL device including the charge generation structure described above.
- a preferred aspect has a translucent anode layer, a light-emitting functional layer, and a reflective cathode layer in this order, and the light-emitting functional layers are arranged in order from the translucent anode layer side to the reflective cathode layer side.
- the charge transfer material is uniformly present in the film plane, and the charge transfer can be effectively performed in the film thickness direction. It becomes a charge generation structure.
- FIG. 1 is a cross-sectional view illustrating a charge generation structure according to an embodiment of the invention
- FIG. 2 is a cross-sectional view illustrating the configuration of the organic EL element of FIG. 1 in further detail;
- the charge generation structure 7 of the embodiment of the present invention includes a charge transfer material layer 4 sandwiched between two charge transport layers 4-1 and 4-1 so that both surfaces are in contact with each other. contains -2.
- the charge transfer material layer 4-2 contains only the charge transfer material described later.
- the charge transfer material layer 4-2 has an average film thickness of 0.05 nm or more and 2.0 nm or less.
- the average film thickness of the charge transfer material layer 4-2 is, for example, about 0.2 nm, which is a typical atomic diameter of electron-donating metals, which will be described later. In this way, while the charge transfer property of the charge transfer material layer 4-2 is maximized, the transport property of the charge transport layer 4-1 sandwiching the charge transfer material layer 4-2 is inhibited. Not likely. From the viewpoint of the above concept, the average thickness of the charge transfer material layer 4-2 is preferably 1 nm or less, more preferably 0.5 nm or less. Within this range, a higher performance charge generating structure is constructed.
- the charge generation structure 7 includes a charge transport layer 4-1 sandwiched between two charge transfer material layers 4-2 and 4-2 so that both surfaces are in contact with each other. It is preferably included as a transport layer.
- the intermediate charge transport layer 4-1 sandwiched between the charge transfer material layers 4-2, 4-2 preferably contains only the charge transport material. As will be described later, the intermediate charge transport layer 4-1 preferably has an average thickness of 0.25 nm or more and 4 nm or less.
- the charge generation structure 7 preferably includes two or more intermediate charge transport layers 4-1 and seven or less layers.
- the number of layers of the charge transfer material layer 4-2 is preferably one less than the number of layers of the intermediate charge transport layer 4-1, and more preferably 1 to 6 layers. .
- the charge transport layer 4-1 and the charge transfer material layer 4-2 are formed by vacuum deposition.
- the crucible temperature of the vacuum deposition apparatus used in the vacuum deposition method is preferably maintained stably so that the material is always vaporized at a constant rate.
- the vacuum deposition apparatus used for the vacuum deposition method preferably controls the supply of the vaporized material from the crucible in a stable vaporized state to the film forming surface only by opening and closing the film forming shutter.
- connection unit 4 is preferably arranged so as to be in direct contact with the light emitting unit 3-1.
- the connection unit 4 can also include two charge generating structures 7, as shown in FIG.
- the connection unit 4 preferably has a separation layer 8 between the charge generating structures 7 for the purpose of improving the reliability of the charge generating structures 7 .
- the connection unit 4 preferably has a blocking layer 9 between the charge generating structure 7 and the light emitting unit 3-2.
- the separation layer 8 and the blocking layer 9 can be layers similar to the charge transport layer 4-1, and among them, a layer similar to the intermediate charge transport layer 4-1 sandwiched between the charge transfer material layers 4-2 and 4-2. It is preferable to Separation layer 8 and blocking layer 9 are also preferably bipolar transport layers.
- Organic materials used for the separation layer 8 and blocking layer 9 are not particularly limited, and any known materials can be used.
- the organic material used for the separation layer 8 and the blocking layer 9 is, from the viewpoint of exhibiting a high charge generation function, for example, in the organic EL device 10 shown in FIG. preferable.
- the HOMO (highest occupied molecular orbital) level of the organic material is preferably shallower than the HOMO level of the organic material used for the hole injection layer in the light emitting unit 3-2. This is to block holes in the hole injection layer from moving to the isolation layer 8 .
- the blocking layer 9 preferably has an average film thickness of 1 nm or more and 5 nm or less.
- the film thicknesses of the separation layer 8 and blocking layer 9 are preferably 5 nm or more and 40 nm or less.
- the charge transport layer 4-1 is a layer in which electrons and/or holes can move in the thickness direction by applying a voltage in the thickness direction of the layer, and the charge that mainly moves is the electron.
- the layer that is an electron transport layer, the layer that is holes is called a hole transport layer, and the layer that is both is called a bipolar transport layer, respectively.
- Such charge-transporting layer 4-1 is a layer mainly composed of a charge-transporting material, and may be a layer containing a material other than the charge-transporting material. It can also be a layer consisting of only a single charge transport material.
- charge transfer material only or “charge transport material only” means a plurality of compounds or only a single metal having the same type of charge transfer property or charge transport property, preferably a single compound or single metal only.
- charge transport layer 4-1 There are no particular restrictions on the charge transport layer 4-1, and any known material can be used.
- the intermediate charge transport layer 4-1 sandwiched between the charge transfer material layers 4-2, 4-2 preferably has an average thickness of 0.1 nm or more, more preferably 0.25 nm or more.
- the intermediate charge transport layer 4-1 preferably has an average thickness of 5 nm or less, more preferably 4 nm or less. The thinner the intermediate charge transport layer 4-1, the more likely it is to lose reliability. This is due to the charge transfer material diffusing beyond the charge generating structure 7 .
- the intermediate charge transport layers 4-1 may all have the same film thickness or different film thicknesses. It is preferable that the film thickness is larger than that of the intermediate charge transport layer 4-1 on the side of the long-wavelength phosphorescent light-emitting unit 3-2.
- the intermediate charge transport layer 4-1 preferably contains an electron transport material.
- the intermediate charge transport layer 4-1 is preferably composed of an electron transport material only, more preferably composed of a single electron transport material only.
- the electron transport material is preferably one selected from the group consisting of quinolinolato-based metal complexes, anthracene-based compounds, oxadiazole-based compounds, triazole-based compounds, phenanthroline-based compounds, and silole-based compounds.
- the charge transfer material layer 4-2 preferably contains only the charge transfer material, and more preferably consists of only a single charge transfer material.
- the charge transfer material layer 4-2 preferably contains only an electron donating material, and more preferably consists of only an electron donating material.
- the electron donating material is one selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, compounds of these metals, phthalocyanine complexes having these metals as central metals, and dihydroimidazole compounds. is preferred, and ytterbium (Yb) is more preferred.
- the material forming the charge transfer material layer 4-2 is preferably an electron donating material.
- the electron donating material preferably contains an electron donating metal such as an alkali metal, alkaline earth metal, rare earth metal or compound of these metals.
- Alkali metals such as lithium (Li), alkaline earth metals such as magnesium (Mg) and calcium (Ca), and rare earth metals such as ytterbium (Yb) and cerium (Ce) are preferably used. Alloys of these metals with aluminum (Al), silver (Ag), indium (In), or the like are also preferably used.
- a metal having a large atomic radius is preferable, and ytterbium (Yb) is particularly preferable, in order to prevent the intralayer diffusion of the electron-donating material.
- the organic EL element 10 has a structure in which the light-emitting functional layer 6 is sandwiched between the anode layer 2 and the cathode layer 5, and generally the structure is formed on the substrate 1. .
- the organic EL element 10 includes a translucent anode layer 2 , a light-emitting functional layer 6 and a reflective cathode layer 5 in this order on a translucent substrate 1 .
- the light-emitting functional layer 6 is composed of a light-emitting unit 3-1, a connection unit 4, and a light-emitting unit 3-2 in order from the translucent anode layer 2 side toward the reflective cathode layer 5 side.
- the organic EL element 10 may have a configuration having three or more light-emitting units 3. good.
- a connection unit 4 is provided between each of two adjacent light emitting units 3,3. That is, in the organic EL device 10 having three or more light emitting units 3, it is preferable that the connection unit 4 is sandwiched between the adjacent light emitting units 3,3. At least one connection unit 4 among these connection units 4 may be provided with the charge generation structure 7 .
- the substrate 1 is not particularly limited, and known substrates can be used. For example, it is appropriately selected and used from translucent substrates such as glass, silicon substrates, flexible film substrates, and the like. In the case of the bottom emission type organic EL device 10 that extracts light from the substrate 1 side, a translucent substrate is generally used. Such a translucent substrate preferably has a transmittance of 80% or more, more preferably 95% or more, in the visible light region from the viewpoint of reducing the loss of light emitted to the outside with respect to emitted light. More preferred.
- the translucent anode layer 2 is not particularly limited, and known materials can be used. Examples of materials constituting the translucent anode layer 2 include indium-tin oxide (ITO), indium-zinc oxide (IZO), tin oxide (SnO 2 ), and zinc oxide (ZnO). ITO or IZO, which have high transparency, can be preferably used as the material for the translucent anode layer 2 from the viewpoint of the efficiency of extracting light generated from the light-emitting layer and the ease of patterning. It may be doped with one or more dopants such as aluminum, gallium, silicon, boron, niobium, and the like.
- ITO indium-tin oxide
- IZO indium-zinc oxide
- SnO 2 tin oxide
- ZnO zinc oxide
- ITO or IZO which have high transparency, can be preferably used as the material for the translucent anode layer 2 from the viewpoint of the efficiency of extracting light generated from the light-emitting layer and the ease of patterning. It
- the translucent anode layer 2 preferably has a transmittance of 70% or more, more preferably 80% or more, and particularly preferably 90% or more in the visible light region.
- the translucent anode layer 2 can be formed by, for example, a sputtering method, a thermal CVD method, or the like.
- the light-emitting functional layer 6 has a laminated structure in which a plurality of layers are laminated.
- the light-emitting functional layer 6 includes a short-wavelength fluorescent light-emitting unit 3-1, a connection unit 4, and a long-wavelength phosphorescent light-emitting unit 3-2.
- the method for forming each layer is not particularly limited, and some organic layers can be formed by a method such as spin coating, in addition to the vacuum deposition method.
- the organic material used for the light-emitting layer is not particularly limited, and any known material can be used.
- the light-emitting unit 3 includes at least one light-emitting layer substantially made of an organic compound, and may further include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer.
- a hole transport layer and the like are provided on the anode layer 2 side of the light emitting layer, and an electron transport layer and the like are provided on the cathode layer 5 side of the light emitting layer.
- the light-emitting unit 3-2 arranged on the cathode layer 5 side with respect to the connection unit 4 has at least one phosphorescent light-emitting material having a peak top at 500 to 600 nm and a peak top at 600 to 700 nm. It is preferred to have at least one emissive layer containing at least one phosphorescent emissive material.
- connection unit 4 injects electrons into the short-wavelength fluorescence emission unit 3-1 side and injects holes into the long-wavelength phosphorescence emission unit 3-2 side.
- the connection unit 4 includes a charge generating structure 7 and is sandwiched between two light emitting units 3-1, 3-2.
- the charge generating structure 7 is alternately composed of a charge transport layer 4-1, a charge transfer material layer 4-2, and a charge transport layer 4-1 in this order from the translucent anode layer 2 side. It is a laminated structure. That is, the charge generating structure 7 starts from the charge transport layer 4-1 in the film thickness direction, and the charge transfer material layer 4-2 and the charge transport layer 4-1 are alternately laminated to form the charge transport layer 4-1. It is a multi-layered structure ending with
- Cathode layer 5 As a material constituting the cathode layer 5, it is preferable to use a metal having a small work function, an alloy thereof, a metal oxide, or the like. Alkaline metals such as lithium (Li) and alkaline earth metals such as magnesium (Mg) and calcium (Ca) are examples of metals having a small work function. As a material for forming the cathode layer 5, a single metal such as a rare earth metal, or an alloy of these metals with aluminum (Al), indium (In), silver (Ag), or the like can be used.
- an organometallic complex compound containing at least one selected from the group consisting of alkaline earth metal ions and alkali metal ions can be used.
- a metal capable of reducing metal ions in the complex compound to a metal in vacuum such as aluminum (Al), zirconium (Zr), titanium (Ti), silicon (Si), or the like, or It is preferred to use metal-containing alloys.
- connection unit 4 has the blocking layer 9 between the charge generation structure 7 and the light emitting unit 3-2, but the present invention is not limited to this.
- the blocking layer 9 may not be provided between the charge generation structure 7 and the light emitting unit 3-2.
- connection unit 4 has the separation layer 8 between the charge generation structures 7, but the present invention is not limited to this. There may be no separation layer 8 between charge generating structures 7 .
- connection unit 4 includes two charge generation structures 7 in the above embodiment, the present invention is not limited to this.
- the connection unit 4 may include one charge generating structure 7, or may include three or more.
- the charge generation structure 7 includes two to seven layers of the intermediate charge transport layer 4-1, but the present invention is not limited to this.
- the charge generating structure 7 may include eight or more layers.
- each constituent member can be freely replaced or added between the embodiments.
- an organic EL device having a connection unit including the charge generation structure was produced and subjected to current-voltage measurement. Specifically, a bottom emission type organic EL device having a light emitting region of 80 mm ⁇ 80 mm was fabricated on a glass substrate having an ITO film (thickness: 120 nm) formed thereon as a patterned translucent anode layer.
- a short-wavelength fluorescence emission unit was formed on the ITO translucent anode layer. Specifically, first, on the ITO translucent anode layer, as a hole injection layer, an organic material having hole-transporting properties and an electron-accepting material were formed to a thickness of 14 nm by vacuum evaporation.
- an organic material having hole transport performance was formed with a film thickness of 195 nm by vacuum deposition.
- an organic material having electron-transporting properties and a fluorescent organic material having a peak top at 450 to 500 nm were formed with a film thickness of 20 nm by vacuum deposition.
- an organic material having electron transport performance was formed with a film thickness of 30 nm by a vacuum deposition method.
- a connecting unit was formed on the short-wavelength fluorescence emitting unit.
- a connection unit composed of a charge generation structure and a blocking layer was formed in this order on the electron transport layer.
- an electron transporting material A having a thickness of 4.5 nm as a charge transporting layer
- an electron donating material having a thickness of 0.1 nm as a charge transfer material layer
- a charge transporting layer As the charge generating structure, an electron transporting material A having a thickness of 4.5 nm as a charge transporting layer, an electron donating material having a thickness of 0.1 nm as a charge transfer material layer, and a charge transporting layer.
- An electron transporting material B was formed to a thickness of 0.5 nm as a film by a vacuum deposition method.
- an electron-transporting material was formed as a blocking layer with a thickness of 3 nm by vacuum deposition.
- a long-wavelength phosphorescent unit was formed on the connecting unit. Specifically, an organic material having a hole-transporting property and an electron-accepting material were formed to a thickness of 12 nm as a hole injection layer on the connection unit by vacuum deposition.
- an organic material having hole transport performance was formed with a film thickness of 30 nm by a vacuum deposition method.
- an organic material having electron-transporting properties As a light-emitting layer, an organic material having electron-transporting properties, a phosphorescent organic material having a peak top at 500 to 600 nm, and a phosphorescent light-emitting material having a peak top at 600 to 700 nm are formed in a film thickness of 10 nm by vacuum deposition. formed.
- an organic material having electron transport performance was formed with a film thickness of 7.5 nm by vacuum deposition.
- an organic material having an electron transport performance different from that described above was formed with a film thickness of 63 nm by vacuum deposition.
- Li was formed with a film thickness of 0.4 nm by a vacuum deposition method.
- Ag was formed as a cathode with a film thickness of 120 nm on the long-wavelength phosphorescent light-emitting unit by a vacuum deposition method.
- a sealing film was formed by the CVD method on the region covering the entire surface of the element.
- the luminance retention rate was 81 when a current with a current density of 5.7 mA/cm 2 was continuously applied for 500 hours under conditions of a temperature of 85 ° C. and a humidity of 85%. A good value of 0.6% was shown.
- translucent substrate 2 translucent anode layer 3 light-emitting unit 3-1 short-wavelength fluorescent light-emitting unit 3-2 long-wavelength phosphorescent light-emitting unit 4 connection unit 4-1 intermediate charge transport layer 4-2 charge transfer material layer 5 cathode layer 6 light-emitting functional layer 7 charge generation structure 8 separation layer 9 blocking layer 10 organic EL element
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Abstract
Description
有機EL素子は、構成する有機材料等の改良により、素子の駆動電圧が格段に下げられると共に、発光効率が高められている。
しかしながら、電流密度を高めると、発生する熱量が増大するので、有機EL素子を構成する有機材料そのものの劣化が促進されてしまう問題がある。そのため、駆動電流を大きくすることなく、発光輝度を上げるための方策が必要である。
特許文献3では、五酸化バナジウムに代えて、三酸化モリブデンを用いた接続ユニットを用いることが提案されている。
このような積層手法は、Multi-Photon Emission(MPE)と称される。
特許文献2によると、Alのような熱還元性金属によってLiq中のLiイオンが還元され、これがラジカルアニオン発生手段として作用する。そのために、Alqのような電子輸送性有機物がラジカルアニオン状態で存在し、電子輸送層に注入され得る電子を生じさせる、と解される。
有機EL素子は、接続ユニットの機能が低下すると、駆動電圧の増大を招き、電力効率低下に繋がってしまう。
従来の接続ユニットに含まれる電荷発生構造は、例えば、電子輸送材料をホスト材料として、これに電子供与性材料がドーピングされた層を含むが、ドーピング材料の組成比によって、その物性が大きく変化する。そのため、電荷発生構造は、接続ユニットの上述の不安定性の原因となり易い。
これを防止するには、電子供与性材料がドーピングされた層を形成する際に、組成比が崩れないよう精密なコントロールが必要となり、成膜レートが安定するまで時間を要し、その分材料をロスしてしまう課題を有する。
本様相は、2層の電荷輸送層に、その両面が接するように挟持された電荷授受材料層を含む電荷発生構造であって、該電荷輸送層が、電荷輸送材料を含み、かつ、該電荷授受材料層が、電荷授受材料のみを含み、平均膜厚が0.05nm以上、2.0nm以下である、電荷発生構造に関連するものである。
そして、本様相は、電荷輸送層/電荷授受材料のみを含む電荷授受材料層/電荷輸送層の多層構造の電荷発生構造であり、上述のホスト材料にドーパントがドーピングされた層の代替として、「電荷授受材料のみを含む電荷授受材料層」が用いられていることが、その特徴の一つである。
本様相によれば、ドーピングのための共蒸着をすることなく、電荷授受材料のみを蒸着するプロセスで形成可能である。そのため、ドーパントが、共蒸着困難な材料であったり、材料蒸気を含む蒸気含有ガスの流れであるガスフローにより製膜室に材料を輸送するガスフロー蒸着が困難な材料であったりしても、電荷発生構造を形成可能である。
すなわち、このようなガスフロー蒸着を行うガスフロー蒸着装置を用い、その製膜過程の一部を、ガスフロー蒸着でなく、材料蒸気の真空雰囲気での平均自由行程起因の到達に基づく蒸着とすることが可能であることが本発明の特徴の一つである。また、本様相の電荷発生構造は、この蒸着方法を用いて製造することが好ましい製造方法となる。
換言すれば、本様相の電荷発生構造とすることで、ガスフロー製膜(別名:ガスキャリア製膜)用の製膜装置を用いることで、全体として高い材料利用効率や生産性を維持しつつ、非常に薄い電荷授受材料層を、平均自由行程の範囲で蒸着とすることが可能であり、電荷の授受性及び輸送性に優れ、高信頼性、高生産性、及び高性能の電荷発生構造となる。
そのため、管理項目の単一化及び、共蒸着時に発生する材料ロスを削減可能な、生産性の高い製造方法によっても形成できる。
その結果、本様相の電荷発生構造を含む素子、例えば、有機EL素子は、高性能、高信頼性、かつ、安価となる。
すなわち、本様相は、通常は共蒸着してドーピングしないと授受性が発揮されないと考えられるドーパントを、特定の構造のドーパント単層として含む構造となっている。本様相は、このような構造とすることにより、効果的に電荷発生可能であることを見出したものであるとも言える。
言い換えれば、本様相の電荷発生構造は、各材料の単層製膜によって形成可能であり、共蒸着時に必要なレートあわせ工程がなくなる。その結果、本様相の電荷発生構造は、従来に比べて生産性が向上し、レート合わせ工程で消費されていた材料の分だけ低コストで生産する事が可能となる。さらには、本様相の電荷発生構造は、例えばガスキャリア製膜装置を用いて形成できる。
本様相は、2層の前記電荷授受材料層に、その両面が接するように挟持された電荷輸送層を、中間電荷輸送層として含み、前記中間電荷輸送層は、電荷輸送材料のみを含み、平均膜厚が0.25nm以上、4nm以下であることに関連する。
そのため、電荷授受材料層の電荷授受作用が効果的に奏され、より優れた特性をもち、かつ、より高信頼性及び高性能の電荷発生構造となる。
電子輸送材料は、キノリノラト系金属錯体、アントラセン系化合物、オキサジアゾール系化合物、トリアゾール系化合物、フェナントロリン系化合物、及びシロール系化合物からなる群から選ばれる1種以上であることが好ましい。
前記電荷授受材料は、電子供与性材料であることが好ましい。
前記電子供与性材料は、アルカリ金属、アルカリ土類金属、希土類金属、これらの金属の化合物、これらの金属を中心金属とするフタロシアニン錯体、及びジヒドロイミダゾール化合物からなる群から選ばれる1種以上であることが好ましい。
このような電荷発生構造は、例えば、有機EL素子において、後述する接続ユニットの陽極側に設けられることが好ましい。
本発明の実施形態の電荷発生構造7は、図2,図3のように、2層の電荷輸送層4-1,4-1に、その両面が接するように挟持された電荷授受材料層4-2を含んでいる。
電荷授受材料層4-2は、後述する電荷授受材料のみを含んでいる。
電荷授受材料層4-2は、その平均膜厚が0.05nm以上、2.0nm以下である。
電荷授受材料層4-2の平均膜厚は、上記した考えの観点から、1nm以下であることが好ましく、0.5nm以下であることがより好ましい。
この範囲であれば、より高性能の電荷発生構造が構成される。
電荷授受材料層4-2,4-2に挟まれる中間電荷輸送層4-1は、電荷輸送材料のみを含むことが好ましい。
中間電荷輸送層4-1は、後述するように、その平均膜厚が0.25nm以上、4nm以下であることが好ましい。
また、電荷発生構造7は、電荷授受材料層4-2の層数が中間電荷輸送層4-1の層数よりも1層少ないことが好ましく、1層以上、6層以下含むことがより好ましい。
真空蒸着法に用いる真空蒸着装置の坩堝温度は、常に材料が一定速度にて気化するように安定的に維持することが好ましい。
真空蒸着法に用いる真空蒸着装置は、安定した気化状態の坩堝からの気化材料の製膜面への供給を、製膜シャッターの開閉のみで制御することが好ましい。
また、接続ユニット4は、図3のように、電荷発生構造7を2個含むことができる。
この場合、接続ユニット4は、電荷発生構造7の信頼性を改善させる目的で、電荷発生構造7と電荷発生構造7の間に、分離層8を有することが好ましい。また、接続ユニット4は、電荷発生構造7と発光ユニット3-2の間に、阻止層9を有することが好ましい。
分離層8及び阻止層9は、バイポーラ輸送層とすることも好ましい。
分離層8及び阻止層9に用いられる有機材料は、特に制限がなく、公知の任意の材料を使用できる。
分離層8及び阻止層9に用いられる有機材料は、高い電荷発生機能を発揮せしめる観点から、例えば図1に示すような有機EL素子10においては、駆動電圧を大きくしないために、電子輸送材料が好ましい。
阻止層9は、その平均膜厚が1nm以上、5nm以下であることが好ましい。
電荷輸送層4-1は、層の厚み方向への電圧の印加により、電子、及び/又は、ホールが当該厚み方向に移動可能な層であり、主に移動する電荷が、電子である層を電子輸送層、ホールである層をホール輸送層、両方である層をバイポーラ輸送層、と各々呼称する。
上述の「電荷授受材料のみ」又は「電荷輸送材料のみ」とは、同種類の電荷授受性又は電荷輸送性を有する複数の化合物又は単一金属のみ、を意味するが、好ましくは、単一化合物又は単一金属のみ、を意味する。
中間電荷輸送層4-1は、その平均膜厚が5nm以下であることが好ましく、4nm以下であることがより好ましい。
中間電荷輸送層4-1は、薄くするほど信頼性を損ないやすく、厚くするほど、例えば有機EL素子10の駆動電圧が上がり発光効率が下がりやすい等、性能が低下する傾向がある。これは、電荷授受材料が電荷発生構造7を越えて拡散することに起因する。
中間電荷輸送層4-1は、いずれも同じ膜厚であってもよいし、異なる膜厚であってもよいが、短波長蛍光発光ユニット3-1側の中間電荷輸送層4-1は、長波長燐光発光ユニット3-2側の中間電荷輸送層4-1に比べて膜厚が大きいことが好ましい。
中間電荷輸送層4-1は、電子輸送材料を含むことが好ましい。
中間電荷輸送層4-1は、電子輸送材料のみから構成されることが好ましく、単一の電子輸送材料のみから構成されることがより好ましい。
当該電子輸送材料としては、キノリノラト系金属錯体、アントラセン系化合物、オキサジアゾール系化合物、トリアゾール系化合物、フェナントロリン系化合物、及びシロール系化合物からなる群から選ばれる1種であることが好ましい。
電荷授受材料層4-2は、電荷授受材料のみを含むことが好ましく、単一の電荷授受材料のみから構成されることがより好ましい。
電荷授受材料層4-2は、電子供与性材料のみを含むことが好ましく、電子供与性材料のみから構成されることがより好ましい。
当該電子供与性材料としては、アルカリ金属、アルカリ土類金属、希土類金属、これらの金属の化合物、これらの金属を中心金属とするフタロシアニン錯体、及びジヒドロイミダゾール化合物からなる群から選ばれる1種であることが好ましく、イッテルビウム(Yb)であることがより好ましい。
前記電子供与性材料がカチオン状態になる際に電子を放出し、放出された電子は隣接する電荷輸送層4-1に移動する。
電子供与性材料は、アルカリ金属,アルカリ土類金属,希土類金属あるいはこれらの金属の化合物のように、電子供与性の金属を含有することが好ましい。
アルカリ金属としてはリチウム(Li)等、アルカリ土類金属としてはマグネシウム(Mg),カルシウム(Ca)等、希土類金属としては、イッテルビウム(Yb),セリウム(Ce)等が好適に用いられる。
また、これらの金属とアルミニウム(Al)、銀(Ag)、インジウム(In)等との合金も好適に用いられる。
中でも電子供与性材料の層内拡散を防止するために、原子半径が大きい金属が好ましく、イッテルビウム(Yb)が特に好ましい。
有機EL素子10は、図1,図3のように、陽極層2と陰極層5との間に発光機能層6が挟持された構造を有し、一般に当該構造が基板1上に形成される。
有機EL素子10は、透光性基板1上に順に、透光性陽極層2と、発光機能層6と、反射性陰極層5とを備えている。
発光機能層6は、透光性陽極層2側から反射性陰極層5側に向かって順に、発光ユニット3-1、接続ユニット4、及び発光ユニット3-2で構成されている。
3以上の発光ユニット3を有する構成においては、隣接する2つの発光ユニット3,3間のそれぞれに、接続ユニット4が設けられていることが好ましい。
すなわち、3以上の発光ユニット3を有する有機EL素子10は、各隣接する発光ユニット3,3で接続ユニット4を挟んでいることが好ましい。
これらの接続ユニット4のうち、少なくとも一つの接続ユニット4が電荷発生構造7を備えていればよい。
基板1は、特に制限はなく、公知の基板が使用可能であり、例えば、ガラスのような透光性基板、シリコン基板、フレキシブルなフィルム基板などから適宜選択され用いられる。
基板1側から光を取り出すボトムエミッション型の有機EL素子10の場合、一般に透光性基板が用いられる。
そのような透光性基板は、発光した光に対する、外部に放射する光のロスを減少する観点から、可視光域における透過率が80%以上であることが好ましく、95%以上であることがさらに好ましい。
透光性陽極層2は、特に制限はなく、公知のものが使用できる。
透光性陽極層2を構成する材料は、例えば、インジウム・スズ酸化物(ITO)、インジウム・亜鉛酸化物(IZO)、酸化スズ(SnO2)、酸化亜鉛(ZnO)などが挙げられる。
透光性陽極層2を構成する材料は、発光層から発生した光の取り出し効率やパターニングの容易性の観点から、透明性が高いITOあるいはIZOを好ましく使用することができ、必要に応じて、例えばアルミニウム、ガリウム、ケイ素、ホウ素、ニオブなどの1種以上のドーパントがドーピングされていてもよい。
透光性陽極層2は、透明性の観点から、可視光域における透過率が70%以上であることが好ましく、80%以上であることがさらに好ましく、90%以上であることが特に好ましい。
透光性陽極層2は、例えば、スパッタ法や熱CVD法等により形成することができる。
発光機能層6は、複数の層を積層した積層構造を有する。
発光機能層6は、短波長蛍光発光ユニット3-1、接続ユニット4、及び長波長燐光発光ユニット3-2を含んでいる。
各層の成膜方法については、特に制限はなく、一部の有機層は真空蒸着法の他に、例えばスピンコート法などの方法によって形成することができる。
また、これらの層である後述する、ホール注入層、ホール輸送層、発光層、電子輸送層、電子注入層などに用いられる物質についても特に制限がなく、公知の任意の物質を適宜用いることができる。
さらに、発光層に用いられる有機材料についても、特に制限はなく、公知の任意の物質を使用できる。
有機EL素子10は、接続ユニット4に対して陰極層5側に配された発光ユニット3-2が500~600nmにピークトップを有する少なくとも1つの燐光発光材料、及び600~700nmにピークトップを有する少なくとも1つの燐光発光材料を含んだ少なくとも1つの発光層を有することが好ましい。
接続ユニット4は、電荷発生構造7を含むものであり、2つの発光ユニット3-1,3-2の間に挟まれている。
すなわち、電荷発生構造7は、膜厚方向に、電荷輸送層4-1から始まり、電荷授受材料層4-2と電荷輸送層4-1が交互に繰り返して積層され、電荷輸送層4-1で終わる多層構造である。
陰極層5を構成する材料としては、仕事関数が小さい金属、又はその合金や金属酸化物等が用いられることが好ましい。
仕事関数が小さい金属として、アルカリ金属ではリチウム(Li)等、アルカリ土類金属ではマグネシウム(Mg),カルシウム(Ca)等が例示される。
また陰極層5を構成する材料としては、希土類金属等からなる金属単体、あるいはこれらの金属とアルミニウム(Al),インジウム(In),銀(Ag)等の合金等が用いられ得る。
また、陰極層5に接する有機層としては、アルカリ土類金属イオン、アルカリ金属イオンからなる群から選択される少なくとも1種を含む有機金属錯体化合物を用いることもできる。
この場合、陰極層5として、当該錯体化合物中の金属イオンを真空中で金属に還元し得る金属、例えばアルミニウム(Al),ジルコニウム(Zr),チタン(Ti),ケイ素(Si)等もしくはこれらの金属を含有する合金を用いることが好ましい。
本発明の電荷発生構造の動作を確認するために、電荷発生構造を含む接続ユニットを有する有機EL素子を作製し、電流-電圧測定を行った。
具体的には、パターニングされた透光性陽極層としてのITO膜(膜厚120nm)が形成されたガラス基板上に、80mm×80mmの発光領域を有するボトムエミッション型の有機EL素子を作製した。
具体的には、まず、ITO透光性陽極層上に、ホール注入層として、ホール輸送性能を有する有機材料と、電子受容性材料を、真空蒸着法により14nmの膜厚で形成した。
具体的には、電子輸送層上に、順に、電荷発生構造、阻止層からなる接続ユニットを形成した。
具体的には、電荷発生構造として、順に、電荷輸送層として電子輸送材料Aを4.5nmの膜厚で、電荷授受材料層として電子供与性材料を0.1nmの膜厚で、電荷輸送層として電子輸送材料Bを0.5nmの膜厚で、それぞれ真空蒸着法により形成した。引き続き、阻止層として電子輸送材料を真空蒸着法により3nmの膜厚で形成した。
具体的には、接続ユニット上に、ホール注入層として、ホール輸送性能を有する有機材料と、電子受容性材料を、真空蒸着法により12nmの膜厚で形成した。
2 透光性陽極層
3 発光ユニット
3-1 短波長蛍光発光ユニット
3-2 長波長燐光発光ユニット
4 接続ユニット
4-1 中間電荷輸送層
4-2 電荷授受材料層
5 陰極層
6 発光機能層
7 電荷発生構造
8 分離層
9 阻止層
10 有機EL素子
Claims (7)
- 複数の電荷輸送層と、電荷授受材料層を有し、
前記電荷授受材料層は、2層の電荷輸送層に、その両面が接するように挟まれており、
前記電荷輸送層は、電荷輸送材料を含んでおり、
前記電荷授受材料層は、電荷授受材料のみを含み、かつ平均膜厚が0.05nm以上、2.0nm以下である、電荷発生構造。 - 少なくとも2層の電荷授受材料層を有し、
前記複数の電荷輸送層の中には、前記2層の電荷授受材料層に、その両面が接するように挟まれた中間電荷輸送層があり、
前記中間電荷輸送層は、電荷輸送材料のみを含み、平均膜厚が0.25nm以上、4nm以下である、請求項1に記載の電荷発生構造。 - 前記中間電荷輸送層を、2層以上、7層以下含む、請求項2に記載の電荷発生構造。
- 前記電荷輸送材料は、電子輸送材料であり、
前記電子輸送材料は、キノリノラト系金属錯体、アントラセン系化合物、オキサジアゾール系化合物、トリアゾール系化合物、フェナントロリン系化合物、及びシロール系化合物からなる群から選ばれる1種以上であり、
前記電荷授受材料は、電子供与性材料であり、
前記電子供与性材料は、アルカリ金属、アルカリ土類金属、希土類金属、これらの金属の化合物、これらの金属を中心金属とするフタロシアニン錯体、及びジヒドロイミダゾール化合物からなる群から選ばれる1種以上である、請求項1~3のいずれか1項に記載の電荷発生構造。 - 前記電荷授受材料は、イッテルビウムである、請求項1~4のいずれか1項に記載の電荷発生構造。
- 請求項1~5のいずれか1項に記載の電荷発生構造を含む、有機EL素子。
- 透光性陽極層、発光機能層、及び反射性陰極層をこの順に有し、
前記発光機能層は、前記透光性陽極層側から前記反射性陰極層側に向かう順に、短波長蛍光発光ユニット、接続ユニット、及び、長波長燐光発光ユニットを含み、
前記接続ユニットは、前記短波長蛍光発光ユニット側に電子を注入し、かつ、前記長波長燐光発光ユニット側にホールを注入するものであり、
前記接続ユニットは、前記電荷発生構造を含む、請求項6に記載の有機EL素子。
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JP2003272860A (ja) * | 2002-03-26 | 2003-09-26 | Junji Kido | 有機エレクトロルミネッセント素子 |
JP2017224808A (ja) * | 2016-05-30 | 2017-12-21 | ノヴァレッド ゲーエムベーハー | 有機半導体層を含む有機発光ダイオード |
JP2018055084A (ja) * | 2016-07-01 | 2018-04-05 | 株式会社半導体エネルギー研究所 | 表示装置 |
JP2018092887A (ja) * | 2016-05-20 | 2018-06-14 | 株式会社半導体エネルギー研究所 | 発光装置および電子機器 |
CN108701773A (zh) * | 2016-02-19 | 2018-10-23 | 诺瓦尔德股份有限公司 | 包含用于有机发光二极管(oled)的基质化合物混合物的电子传输层 |
JP2020155766A (ja) * | 2019-03-15 | 2020-09-24 | 株式会社Joled | 自発光素子及び自発光素子の製造方法、並びに自発光表示装置、電子機器 |
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JP2003272860A (ja) * | 2002-03-26 | 2003-09-26 | Junji Kido | 有機エレクトロルミネッセント素子 |
CN108701773A (zh) * | 2016-02-19 | 2018-10-23 | 诺瓦尔德股份有限公司 | 包含用于有机发光二极管(oled)的基质化合物混合物的电子传输层 |
JP2018092887A (ja) * | 2016-05-20 | 2018-06-14 | 株式会社半導体エネルギー研究所 | 発光装置および電子機器 |
JP2017224808A (ja) * | 2016-05-30 | 2017-12-21 | ノヴァレッド ゲーエムベーハー | 有機半導体層を含む有機発光ダイオード |
JP2018055084A (ja) * | 2016-07-01 | 2018-04-05 | 株式会社半導体エネルギー研究所 | 表示装置 |
JP2020155766A (ja) * | 2019-03-15 | 2020-09-24 | 株式会社Joled | 自発光素子及び自発光素子の製造方法、並びに自発光表示装置、電子機器 |
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