JPWO2012115034A1 - Organic electroluminescence element, lighting device and display device - Google Patents

Abstract

Provided is an organic electroluminescence device having a high external extraction quantum efficiency, a low driving voltage, a small voltage increase with time, and a long emission lifetime. The organic electroluminescence device of the present invention is an organic electroluminescence device having at least an anode, a light emitting layer containing at least one phosphorescent dopant, and at least one electron transport layer, and the electron transport layer is at least 1 Two electron transport materials, and the film thickness of the electron transport layer is in the range of 50 to 200 nm. In the electron transport layer, crystal grains of the electron transport material exist, and X-ray diffraction by the crystal grains It is characterized in that a line is observed.

Description

  The present invention relates to an organic electroluminescence element, and further relates to an illumination device and a display device including the organic electroluminescence element.

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter abbreviated as ELD). As a component of ELD, an inorganic electroluminescence element (hereinafter also referred to as an inorganic EL element) and an organic electroluminescence element (hereinafter also referred to as an organic EL element) can be given.

  Inorganic EL elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, the organic EL element has a configuration in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode. Excitons are generated by injecting electrons and holes into the light emitting layer and recombining them. It is an element that emits light by using the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Further, since it is a self-luminous type, it has a wide viewing angle, high visibility, and since it is a thin-film type complete solid-state device, it has attracted attention from the viewpoints of space saving and portability.

  Another major feature of the organic EL element is that it is a surface light source, unlike main light sources that have been used in the past, such as light-emitting diodes and cold cathode tubes. Applications that can effectively utilize this characteristic include illumination light sources and various display backlights. In particular, it is also suitable to be used as a backlight of a liquid crystal full color display whose demand has been increasing in recent years.

  As a problem for using the organic EL element as a backlight of such a display or a light source for illumination, improvement in luminous efficiency and reduction in driving voltage are required.

  A typical organic EL device has a plurality of organic layers such as a light-emitting layer and an electron transport layer between a light-transmitting electrode (usually an anode) and a light-reflective second electrode (usually a cathode) on a substrate. Are laminated. In such an organic EL element, electrons and holes are injected into the light emitting layer by applying a driving voltage, light emission is generated by recombination thereof, and light is extracted through the transparent electrode and the transparent substrate.

  Only a part of the light generated in the light emitting layer is extracted outside due to the influence of the optical characteristics (for example, refractive index) of the anode and the organic layer, the reflectance of the cathode and the kind of the cathode material, and the like. Loss when light is extracted includes loss due to the waveguide mode in which light totally reflected at the interface is generated due to the refractive index difference between the substrate and the conductive layer or between the conductive layer and the organic layer, and the light is confined in the organic layer. Due to the difference in refractive index between the substrate and air, light that is totally reflected at the interface is generated, and the optical loss that occurs when the totally reflected light is multiple-reflected inside the device. There are losses caused by energy transfer to surface plasmons.

  Of the above-mentioned losses, the loss due to the waveguide has been tried to be improved by installing an optically processed sheet called a light extraction sheet at the interface between the substrate and air.

  On the other hand, methods for reducing the loss due to surface plasmons include the method of preventing the generation of surface plasmons by non-metalizing the electrodes, or by increasing the distance between the metal electrode and the light emitting surface and causing the surface plasmons to be generated. Attempts have been made to reduce the electric field. However, demetalization of the former electrode has a problem of deterioration of electron injection property, and the latter has a problem of increase in driving voltage due to an increase in the distance from the light emitting surface to the metal electrode.

  For example, Patent Document 1 improves the light extraction efficiency by adjusting the optical distance between the light emitting surface and the light reflecting surface in the light emitting layer by the film thickness of the light emitting layer and the electron transport layer or the electron injection layer. A configuration is proposed. However, there is no specific description about the driving voltage, and doping to the electron injection layer has been proposed as a method for reducing the driving voltage, but the performance of the organic EL element is still insufficient.

  Patent Document 2 describes an example of an electron injection layer in which a phenanthroline derivative is doped with a tungsten derivative in order to improve the conductivity of the electron transport layer by adding a dopant to the electron injection layer. There is no description of the voltage rise in the area, and there is still a need for improvement.

JP 2008-130485 A International Publication No. 07/054345 Pamphlet

  In view of the above problems, one of the problems of the present invention is to reduce the optical loss taken out to the outside in the organic EL element. It is possible to reduce the light loss due to the surface plasmon described above by increasing the distance between the light emitting layer and the metal electrode by providing an electron transport layer having a thickness in the range of 50 to 200 nm between the light emitting layer and the cathode. It has become possible. However, if the thickness of the electron transport layer is set within this range, the driving voltage increases due to the increase in the thickness, resulting in a problem that the power efficiency of the organic EL element is lowered.

  One of the problems of the organic EL element is a voltage increase with time when a current is applied. In the case of an amorphous film, the fluidity of the molecules in the layer is relatively easily caused by the heat generated when a current is applied, and the orientation and arrangement of the molecules change over time. It is done.

  On the other hand, in the organic EL device, it is important to laminate the adjacent layer interface so that the interface between the adjacent layers is flat and no material mixing occurs. This is because the carrier injection balance is lost, new carrier trap sites are generated by mixing the materials, and when one of the adjacent layers is a light emitting layer, the light emission and excitons are quenched by the mixed material, resulting in a decrease in light emission efficiency. This is to prevent inviting.

  In order to reduce the voltage, in a typical organic EL element, a layer may be further provided between the electron transport layer and the cathode. The material constituting such a layer passes through the electron transport layer to the light emitting layer. It is known that when diffused, the light emission efficiency of the organic EL element as well as the light emission efficiency is seriously damaged.

  As a means for observing the orientation and arrangement of molecules, for example, there is an X-ray diffraction method. In the case of the X-ray diffraction method, for example, even if not all the molecules arranged in the thin film are aligned, a region of a certain size (referred to as a microcrystalline region or a crystal grain) in which the molecules are aligned and aligned. X-ray diffraction lines are observed when present. By the X-ray diffraction method, it can be determined whether the material is amorphous or has crystal grains. The inventors of the present invention formed an electron transport layer in which no X-ray diffraction lines are observed by the X-ray diffraction method, and examined the performance of the light-emitting element. As a result, light loss due to surface plasmons was reduced and light emission efficiency was improved. The drive voltage could not be lowered sufficiently.

  Therefore, the present inventors have intensively studied and found that the presence of crystal grains in which X-ray diffraction lines are observed in the electron transport layer allows carriers to be transported very efficiently, resulting in a decrease in driving voltage. It turned out to be possible.

  Further, when the present inventors studied, a crystal grain by an electron transport material exists as an electron transport layer, and a layer in which an X-ray diffraction line by the crystal grain is observed is used, and the film thickness is in the range of 50 to 200 nm. By doing so, it has become possible to simultaneously solve the improvement of the light emission efficiency by reducing the light loss when taking out the organic EL element to the outside and the suppression of the drive voltage increase due to the increase of the film thickness.

  Further, it has been found that in the organic EL element having a film in which crystal grains of the electron transport material of the present invention exist between the light emitting layer and the cathode, the voltage increase with time as described above can be suppressed.

  This is because the molecules are oriented and arranged in the crystal grain region, so the molecules do not move easily, and since the crystal grains in the layer have a certain size, the fluidity of the molecules in the region other than the crystal grains is suppressed. Expected to be.

  In addition, the presence of crystal grains in the electron transport layer and the low fluidity of molecules in the layer leads to suppression of disturbance at the interface between the electron transport layer and the layer adjacent to the electron transport layer, and the voltage over time. It was estimated that the increase was suppressed. The presence of these crystal grains particularly affects the formation of the electron transport layer or its adjacent layer by a wet process, and the presence of crystal grains in a film that includes solvent molecules and has a large degree of freedom of movement between molecules. Presence is expected to contribute to controlling liquidity.

  In the present invention, when an electron transport layer having a large thickness of 50 to 200 nm is provided between the light emitting layer and the cathode, for example, when a layer is further provided between the cathode and the electron transport layer, this layer is Diffusion of the constituent material into the light emitting layer can be suppressed, resulting in an improvement in the light emission lifetime.

  The above object of the present invention can be achieved by the following means.

1. An organic electroluminescence device having at least an anode, a light emitting layer containing at least one phosphorescent dopant, and at least one electron transport layer,
The electron transport layer contains at least one electron transport material;
The thickness of the electron transport layer is in the range of 50 to 200 nm;
An organic electroluminescence device, wherein crystal grains of the electron transport material are present in the electron transport layer, and X-ray diffraction lines due to the crystal grains are observed.

  2. 2. The organic electroluminescence device according to 1 above, wherein the electron transport layer is made of a single material.

  3. 3. The organic electroluminescence device according to 1 or 2 above, wherein the electron transport material is represented by the following general formula (1).

（式中、Ａｒ_１は置換基を有していても良い芳香族縮合環を表し、Ａｒ_２及びＡｒ_３は置換基を有していても良い芳香環を表し、Ａ_１、Ａｒ_２、Ａｒ_３、ｎ０１、ｎ０２及びｎ０３は、下記式（１）を満足する。ｎ０１は１以上の整数を表し、ｎ０２及びｎ０３は０〜３の整数を表し、ｎ０１＋ｎ０２＋ｎ０３≧２である。ｎ０１、ｎ０２及びｎ０３が２以上の場合、Ａｒ_１、Ａｒ_２及びＡｒ_３は同じでも異なっていても良い。）
式（１）
｛（Ａｒ_１で表される芳香族縮合環を構成する環の数）×ｎ０１｝＋｛（Ａｒ_２で表される芳香族縮合環を構成する環の数）×ｎ０２｝＋｛（Ａｒ_３で表される芳香族縮合環を構成する環の数）×ｎ０３｝≧４
４．一般式（１）の化合物が一般式（ｂ）で表される化合物であることを特徴とする前記１〜３のいずれか１項に記載の有機エレクトロルミネッセンス素子。

(In the formula, Ar ₁ represents an aromatic condensed ring which may have a substituent, Ar ₂ and Ar ₃ represent an aromatic ring which may have a substituent, and A ₁ , Ar ₂ , Ar ₃ , n01, n02 and n03 satisfy the following formula (1): n01 represents an integer of 1 or more, n02 and n03 represent an integer of 0 to 3, and n01 + n02 + n03 ≧ 2. When Ar is 2 or more, Ar ₁ , Ar ₂ and Ar ₃ may be the same or different.)
Formula (1)
{(Number of rings constituting the aromatic condensed ring represented by Ar ₁ ) × n01} + {(Number of rings constituting the aromatic condensed ring represented by Ar ₂ ) × n02} + {(Ar ₃ The number of rings constituting the aromatic condensed ring represented by: xn03} ≧ 4
4). 4. The organic electroluminescence device as described in any one of 1 to 3 above, wherein the compound of the general formula (1) is a compound represented by the general formula (b).

（式中、Ｘ_２０はＯ又はＳを表し、Ｘ_２１〜Ｘ_２８はＣ（Ｒ_２０）又はＮを表し、Ｒ_２０は水素原子又は置換基を表す。Ｒ_２０のうち少なくとも１つは下記一般式（ｂ１）で表される。）

（式中Ｌ_２０は芳香族炭化水素環又は芳香族複素環から導出される２価の連結基を表す。ｎ２３は０又は１〜３の整数を表し、ｎ２３が２以上の場合複数のＬ_２０は同じでも異なっていてもよい。＊は一般式（ｂ）の母核との連結部位を表す。Ａｒ_２０は下記一般式（ｂ２）で表される基を表す。）

（式中、Ｘ_２９はＮ（Ｒ_２１）、Ｏ又はＳを表し、Ｅ_２１〜Ｅ_２８はＣ（Ｒ_２２）又はＮを表し、Ｒ_２１及びＲ_２２は水素原子、置換基又はＬ_２０との連結部位を表す。＊はＬ_２０との連結部位を表す。）
５．前記電子輸送層がウェットプロセスで形成されることを特徴とする前記１〜４のいずれか１項に記載の有機エレクトロルミネッセンス素子。

(In the formula, X ₂₀ represents O or S, X _{21 to} X ₂₈ represent C (R ₂₀ ) or N, R ₂₀ represents a hydrogen atom or a substituent. At least one of R ₂₀ is represented by the following general formula: (Represented by the formula (b1))

(In the formula, L ₂₀ represents a divalent linking group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. N23 represents 0 or an integer of 1 to 3, and when n23 is 2 or more, a plurality of L ₂₀ May be the same or different. * Represents a site of connection with the mother nucleus of the general formula (b), Ar ₂₀ represents a group represented by the following general formula (b2).

(In the formula, X ₂₉ represents N (R ₂₁ ), O or S, E _{21 to} E ₂₈ represent C (R ₂₂ ) or N, and R ₂₁ and R ₂₂ represent a hydrogen atom, a substituent, or L ₂₀ . of represents a linking site. * represents a linking site with L _20.)
5. 5. The organic electroluminescence device according to any one of 1 to 4, wherein the electron transport layer is formed by a wet process.

  6). 6. The organic electroluminescence device according to any one of 1 to 5, wherein the phosphorescent dopant is represented by the following general formula (a).

（式中、Ｒ_１は置換基を表す。ＺはＣ−Ｂ_０と共に５〜７員環を形成するのに必要な非金属原子群を表す。ｎ１は０〜５の整数を表す。Ｂ_０は炭素原子又は窒素原子を表し、Ｂ_１〜Ｂ_５は、Ｃ（Ｒ_１１）、Ｎ、Ｎ（Ｒ_１１）、Ｓ、Ｃ（Ｒ_１１）＝Ｃ（Ｒ_１２）、Ｃ（Ｒ_１１）＝Ｎ、又はＮ＝Ｎを表し、Ｂ_１〜Ｂ_５が共に形成する環は少なくとも一つ窒素原子を有し、単環の芳香族含窒素複素環を表す。Ｒ_１１及びＲ_１２は水素原子又は置換基を表す。Ｍ_１は元素周期表における８〜１０族の金属を表す。Ｘ_１及びＸ_２は炭素原子、窒素原子又は酸素原子を表し、Ｌ_１はＸ_１及びＸ_２と共に２座の配位子を形成する原子群を表す。ｍ１は１〜３の整数を表し、ｍ２は０〜２の整数を表すが、ｍ１＋ｍ２は２又は３である。）
７．前記有機エレクトロルミネッセンス素子が少なくとも２層のウェットプロセスで形成された層を有することを特徴とする前記１〜６のいずれか１項に記載の有機エレクトロルミネッセンス素子。

(In the formula, R ₁ represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring together with C—B _0. N ₁ represents an integer of 0 to 5. B ₀ Represents a carbon atom or a nitrogen atom, and B _{1 to} B ₅ are C (R ₁₁ ), N, N (R ₁₁ ), S, C (R ₁₁ ) = C (R ₁₂ ), C (R ₁₁ ) = N or N = N, and the ring formed by B _{1 to} B ₅ together has at least one nitrogen atom and represents a monocyclic aromatic nitrogen-containing heterocyclic ring, wherein R ₁₁ and R ₁₂ are a hydrogen atom or M ₁ represents a group 8-10 metal in the periodic table, X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ together with X ₁ and X ₂ is a bidentate. And m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 is 2 or 3.
7). 7. The organic electroluminescence element according to any one of 1 to 6, wherein the organic electroluminescence element has a layer formed by at least two wet processes.

  8). 8. The organic electroluminescence device according to any one of 1 to 7 above, which emits white light.

  9. 8. An illuminating device comprising the organic electroluminescent element according to any one of 1 to 7 above.

  10. A display device comprising the organic electroluminescence element according to any one of 1 to 7 above.

  According to the present invention, it is possible to provide an organic electroluminescence device having a high external extraction quantum efficiency, a low driving voltage, a small voltage increase with time, and a long emission lifetime.

It is a figure which shows the X-ray-diffraction line of an electron carrying layer. It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. FIG. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device.

  Hereinafter, the present invention will be described in detail.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in the present invention, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided with a single layer or a plurality of layers.

  The total film thickness of the electron transport layer is in the range of 50 to 200 nm, and X-ray diffraction lines due to crystal grains of the electron transport material are observed.

  An electron transport material (including a hole blocking material and an electron injection material) used for the electron transport layer has a function of transmitting electrons injected from the cathode to the light emitting layer.

  For the purpose of allowing crystal grains to exist in the electron transport layer, the electron transport material is preferably a compound having an aromatic condensed ring, more preferably a compound having two or more aromatic condensed rings. This is because π-π interaction between aromatic rings causes the molecules to be oriented and aligned, making it easier to form crystal grains. Furthermore, aromatic condensed rings interact more than aromatic single rings (such as benzene and pyridine rings). This is because it is large. More preferably, it is an aromatic condensed ring composed of three or more rings. Furthermore, by having two or more aromatic condensed rings in the molecule, the region that interacts between the molecules increases, and it becomes easier to align and align.

  In addition, an organic compound other than the organometallic complex that easily takes a spherical shape in the whole molecule is preferable because of easy arrangement of molecules.

  Preferable examples of conventionally known materials used for the electron transport layer (hereinafter referred to as electron transport materials) include compounds represented by the following general formula (1).

（式中、Ａｒ_１は置換基を有していても良い芳香族縮合環を表し、Ａｒ_２及びＡｒ_３は置換基を有していても良い芳香環を表し、Ａ_１、Ａｒ_２又はＡｒ_３が芳香族縮合環を表す場合、下記式（１）を満足する。ｎ０１は１以上の整数を表し、ｎ０２及びｎ０３は０〜３の整数を表し、ｎ０１＋ｎ０２＋ｎ０３≧２である。ｎ０１、ｎ０２及びｎ０３が２以上の場合、Ａｒ_１、Ａｒ_２及びＡｒ_３は同じでも異なっていても良い。）
式（１）
｛（Ａｒ_１で表される芳香族縮合環を構成する環の数）×ｎ０１｝＋｛（Ａｒ_２で表される芳香族縮合環を構成する環の数）×ｎ０２｝＋｛（Ａｒ_３で表される芳香族縮合環を構成する環の数）×ｎ０３｝≧４
式（１）は、分子内の芳香族縮合環が３つ以下の環で構成されている場合、分子同士がより配向・配列しやすい程度の分子間相互作用を得るために、分子内に２つ以上の芳香族縮合環が存在することを意味する。

(In the formula, Ar ₁ represents an aromatic condensed ring which may have a substituent, Ar ₂ and Ar ₃ represent an aromatic ring which may have a substituent, and A ₁ , Ar ₂ or Ar _{When 3} represents an aromatic condensed ring, the following formula (1) is satisfied: n01 represents an integer of 1 or more, n02 and n03 represent integers of 0 to 3, and n01 + n02 + n03 ≧ 2. When n03 is 2 or more, Ar ₁ , Ar ₂ and Ar ₃ may be the same or different.)
Formula (1)
{(Number of rings constituting the aromatic condensed ring represented by Ar ₁ ) × n01} + {(Number of rings constituting the aromatic condensed ring represented by Ar ₂ ) × n02} + {(Ar ₃ The number of rings constituting the aromatic condensed ring represented by: xn03} ≧ 4
Formula (1) shows that when the aromatic condensed ring in the molecule is composed of 3 or less rings, in order to obtain an intermolecular interaction that allows the molecules to be more easily oriented and aligned, It means that one or more aromatic fused rings are present.

Examples of the substituent that Ar _{1 to} Ar ₃ may have include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, and a dodecyl group). Group, tridecyl group, tetradecyl group, pentadecyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl group (eg ethynyl group, propargyl group etc.), non-aromatic hydrocarbon ring group (eg cyclo Alkyl groups (eg, cyclopentyl group, cyclohexyl group, etc.), cycloalkoxy groups (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), cycloalkylthio groups (eg, cyclopentylthio group, cyclohexylthio group, etc.), tetrahydronaphthalene ring, 9 , 10-Dihydroanthracene ring, biphenyle A monovalent group derived from a ring, etc.), a non-aromatic heterocyclic group (for example, epoxy ring, aziridine ring, thiirane ring, oxetane ring, azetidine ring, thietane ring, tetrahydrofuran ring, dioxolane ring, pyrrolidine ring, pyrazolidine ring , Imidazolidine ring, oxazolidine ring, tetrahydrothiophene ring, sulfolane ring, thiazolidine ring, ε-caprolactone ring, ε-caprolactam ring, piperidine ring, hexahydropyridazine ring, hexahydropyrimidine ring, piperazine ring, morpholine ring, tetrahydropyran ring 1,3-dioxane ring, 1,4-dioxane ring, trioxane ring, tetrahydrothiopyran ring, thiomorpholine ring, thiomorpholine-1,1-dioxide ring, pyranose ring, diazabicyclo [2,2,2] -octane Ring, phenoxazine , Monovalent group derived from phenothiazine ring, oxanthrene ring, thioxanthene ring, phenoxathiin ring, etc.), aromatic hydrocarbon group (for example, benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene) Ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene Ring, perylene ring, pentaphen ring, picene ring, pyrene ring, pyranthrene ring, monovalent group derived from anthraanthrene ring, etc.), aromatic heterocyclic group (for example, silole ring, furan ring, thiophene ring, oxazole) Ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazi Ring, triazine ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzthiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, thienothiophene ring, Consists of carbazole ring, azacarbazole ring (represents any one or more of carbon atoms constituting carbazole ring replaced by nitrogen atom), dibenzosilole ring, dibenzofuran ring, dibenzothiophene ring, benzothiophene ring or dibenzofuran ring Rings in which any one or more carbon atoms are replaced by nitrogen atoms, benzodifuran rings, benzodithiophene rings, acridine rings, benzoquinoline rings, phenazine rings, phenanthridine rings, phenanthroline rings, cyclazine rings, quinines Dorin ring, tepenidine ring, quinindrine ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, naphthofuran ring, naphthothiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, A monovalent group derived from an anthradifuran ring, an anthrathiophene ring, an anthradithiophene ring, a thianthrene ring, a phenoxathiin ring, a dibenzocarbazole ring, an indolocarbazole ring, a dithienobenzene ring, etc.), an alkoxy group (for example, , Methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group) , Ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), arylthio group (for example, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (for example, methyloxycarbonyl group, ethyloxycarbonyl group, Butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, Dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group Group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2- Ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group) , Phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group) Group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group) , Methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylamino Carbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylurea) Group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group) 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2 -Ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenylsulfonyl group, naphthyl group) Rusulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthyl) Amino group, 2-pyridylamino group, etc.), halogen atom (for example, fluorine atom, chlorine atom, bromine atom, fluorinated hydrocarbon group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group) Etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group and the like.

More preferably, Ar ₃ is an aromatic condensed ring and n03 is 1 to 3. The aromatic condensed ring represented by Ar ₁ is preferably a condensed ring in which three or more rings are condensed. Furthermore, the aromatic condensed ring represented by Ar ₃ is also preferably a condensed ring in which three or more rings are condensed. Moreover, it is preferable that n01 + n02 + n03 ≧ 3.

  Among the compounds of the general formula (1), a more preferable compound is a compound of the following general formula (b).

（式中、Ｘ_２０はＯ又はＳを表し、Ｘ_２１〜Ｘ_２８はＣ（Ｒ_２０）又はＮを表し、Ｒ_２０は水素原子又は置換基を表す。Ｒ_２０のうち少なくとも１つは下記一般式（ｂ１）で表される。）
Ｒ_２０で表される置換基としては、前述のＡｒ_１〜Ａｒ_３が有していてもよい置換基等が挙げられる。

(In the formula, X ₂₀ represents O or S, X _{21 to} X ₂₈ represent C (R ₂₀ ) or N, R ₂₀ represents a hydrogen atom or a substituent. At least one of R ₂₀ is represented by the following general formula: (Represented by the formula (b1))
Examples of the substituent represented by R ₂₀ include the substituents that Ar _{1 to} Ar ₃ may have.

（式中Ｌ_２０は芳香族炭化水素環又は芳香族複素環から導出される２価の連結基を表す。ｎ２３は０又は１〜３の整数を表し、ｎ２３が２以上の場合複数のＬ_２０は同じでも異なっていてもよい。＊は一般式（ｂ）の母核との連結部位を表す。Ａｒ_２０は下記一般式（ｂ２）で表される基を表す。）

（式中、Ｘ_２９はＮ（Ｒ_２１）、Ｏ又はＳを表し、Ｅ_２１〜Ｅ_２８はＣ（Ｒ_２２）又はＮを表し、Ｒ_２１及びＲ_２２は水素原子、置換基又はＬ_２０との連結部位を表す。＊はＬ_２０との連結部位を表す。）
Ｒ_２１及びＲ_２２で表される置換基としては、前述のＡｒ_１〜Ａｒ_３が有していてもよい置換基等が挙げられる。

(In the formula, L ₂₀ represents a divalent linking group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. N23 represents 0 or an integer of 1 to 3, and when n23 is 2 or more, a plurality of L ₂₀ May be the same or different. * Represents a site of connection with the mother nucleus of the general formula (b), Ar ₂₀ represents a group represented by the following general formula (b2).

(In the formula, X ₂₉ represents N (R ₂₁ ), O or S, E _{21 to} E ₂₈ represent C (R ₂₂ ) or N, and R ₂₁ and R ₂₂ represent a hydrogen atom, a substituent, or L ₂₀ . of represents a linking site. * represents a linking site with L _20.)
Examples of the substituent represented by R ₂₁ and R ₂₂ include the substituents that Ar _{1 to} Ar ₃ may have.

  Even more preferably, the compound represented by the general formula (b) is a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom in the molecule, or at least one nitrogen as one of the rings constituting the condensed ring. It has a condensed ring having a 6-membered aromatic heterocyclic ring containing an atom.

  The general formula (b) is preferably a compound further represented by the following general formula (b3), and the general formula (b3) is further represented by the general formula (b3-1) or (b3-2). It is preferable that

（式中、Ｘ_２０〜Ｘ_２８は一般式（ｂ）のＸ_２０〜Ｘ_２８と同義であり、Ｘ_２９及びＥ_２１〜Ｅ_２８は一般式（ｂ２）のＸ_２９及びＥ_２１〜Ｅ_２８と同義であり、Ｌ_２０及びｎ２３は一般式（ｂ１）のＬ_２０及びｎ２３と同義である。）

（一般式（ｂ３−１）及び（ｂ３−２）において、Ｘ_２０〜Ｘ_２８は一般式（ｂ）のＸ_２０〜Ｘ_２８と同義であり、Ｘ_２９及びＥ_２１〜Ｅ_２８は一般式（ｂ２）のＸ_２９及びＥ_２１〜Ｅ_２８と同義であり、Ｌ_２０及びｎ２３は一般式（ｂ１）のＬ_２０及びｎ２３と同義である。）

_(Wherein, X 20 _{to X 28} have the same meanings as _X 20 _{to X 28} in formula _{(b), X 29} and _E 21 _{to E 28} and _{X 29} and _E 21 _{to E 28} in the general formula (b2) are _{synonymous, L 20} and n23 have the same meanings as _{L 20} and n23 of the general formula (b1).)

(In the general formula (b3-1) and _{(b3-2), X} 20 ~X ₂₈ has the same meaning as _X 20 _{to X 28} in formula _{(b), X 29} and _E 21 _{to E 28} have the general formula ( b2) have the same meanings as _{X 29} and _E 21 _{to E 28 of, L 20} and n23 have the same meanings as _{L 20} and n23 of the general formula (b1).)

（式中、Ｘ_２０〜Ｘ_２８は一般式（ｂ）のＸ_２０〜Ｘ_２８と同義であり、Ｅ_２１〜Ｅ_２８は一般式（ｂ２）のＥ_２１〜Ｅ_２８と同義であり、Ｌ_２０及びｎ２３は一般式（ｂ１）のＬ_２０及びｎ２３と同義である。）

（一般式（ｂ４−１）及び（ｂ４−２）において、Ｘ_２０〜Ｘ_２８は一般式（ｂ）のＸ_２０〜Ｘ_２８と同義であり、Ｅ_２１〜Ｅ_２８は一般式（ｂ２）のＥ_２１〜Ｅ_２８と同義であり、Ｌ_２０及びｎ２３は一般式（ｂ１）のＬ_２０及びｎ２３と同義である。）
以下に一般式（ｂ）で表される化合物の具体例を示す。なお、下記一般式（ｂ）の化合物は発光層のホスト化合物としても用いることができる。Moreover, it is preferable that general formula (b) is a compound further represented by the following general formula (b4), and general formula (b4) is further represented by general formula (b4-1) or (b4-2). It is preferable that it is a compound.

_(Wherein, X 20 _{to X 28} have the same meanings as _X 20 _{to X 28} in formula _{(b), E} 21 ~E ₂₈ has the same meaning as _E 21 _{to E 28} in the general formula _{(b2), L 20} and n23 have the same meanings as _{L 20} and n23 of the general formula (b1).)

(In the general formula (b4-1) and _{(b4-2), X} 20 ~X ₂₈ has the same meaning as _X 20 _{to X 28} in formula _{(b), E} 21 ~E ₂₈ the general formula (b2) E ₂₁ to E ₂₈ in the above _{formula, L 20} and n23 have the same meanings as _{L 20} and n23 of the general formula (b1).)
Specific examples of the compound represented by the general formula (b) are shown below. In addition, the compound of the following general formula (b) can be used also as a host compound of a light emitting layer.

  The compound represented by the general formula (b) according to the present invention is disclosed in International Publication No. 07/111176 pamphlet, Chem. Mater. It can be synthesized by referring to known methods described in 2008, 20, 5951, Experimental Chemistry Course 5th Edition (Edited by Chemical Society of Japan).

  Below, the synthesis example of the typical compound of the specific example of the said compound is shown.

酢酸２２ｍｌ、無水酢酸２２ｍｌの溶液に化合物（３）６．３ｇ、ヨウ素４．７ｇを加えた。更に化合物（８）３ｇを５分で添加し、硫酸を２〜３滴加え２０分攪拌した。反応液を５％亜硫酸ナトリウム水溶液３００ｍｌにあけ、炭酸ナトリウム１ｇを加えた後、減圧濾過で粗結晶を得た。クロロホルムで再結晶し、化合物（９）４．７ｇ（収率６２．２％）を得た。<< Synthesis of Compound 85 >>

To a solution of 22 ml of acetic acid and 22 ml of acetic anhydride, 6.3 g of compound (3) and 4.7 g of iodine were added. Further, 3 g of compound (8) was added in 5 minutes, and 2 to 3 drops of sulfuric acid was added and stirred for 20 minutes. The reaction solution was poured into 300 ml of 5% aqueous sodium sulfite solution, 1 g of sodium carbonate was added, and then crude crystals were obtained by filtration under reduced pressure. Recrystallization from chloroform gave 4.7 g (yield 62.2%) of compound (9).

  4.7 g of compound (9), 3.2 g of compound (10), 2.3 g of potassium carbonate, 2.1 g of Cu powder and 60 ml of dryDMAc were mixed and stirred for 20 hours under a nitrogen stream. (Internal temperature 135 to 137 ° C.) Insoluble matter was filtered under reduced pressure. 15 ml of well water was added to the filtrate, and the precipitated solid was filtered under reduced pressure. The resulting crude product was purified by column chromatography (silica gel, developing solution: ethyl acetate / toluene) to obtain compound (11). Yield 3.4 g (50% yield).

After mixing 3.4 g of compound (11), 2.3 g of compound (12), 1.0 g of finely divided potassium carbonate, and 50 ml of DMSO, the system was replaced with a nitrogen stream for 20 minutes. Subsequently, 0.45 g of PdCl2dppf was added, followed by heating and stirring for 2 hours. (Internal temperature 75-80 ° C.) Cooled to room temperature, 4 ml of well water was added. The precipitated solid was stirred at room temperature and filtered under reduced pressure. The obtained crude product was purified by column chromatography (silica gel, developing solution: ethyl acetate / toluene), and further recrystallized from a THF / MeOH system to obtain 2.7 g of Compound 85. (Yield 66.0%)
The structure was confirmed by ¹ H-NMR spectrum and mass spectrometry spectrum.

  The Tg of the electron transport material is preferably 100 ° C. or higher in order not to grow large crystal grains by heating. The size of the crystal particles of the electron transport material in the electron transport layer is preferably 1 nm or less in terms of the number average particle diameter observed with an electron microscope from the viewpoint of the light emission lifetime.

  In Patent Document 2, the electron transport material uses a matrix and an n-type dopant. However, in the present invention, since the emission lifetime can be improved, the electron transport layer is preferably formed of a single material.

(Method for forming electron transport layer)
The electron transport layer is made of an electron transport material such as a vacuum deposition method, a wet method (also referred to as a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, or a spraying method. The film can be formed by coating method, curtain coating method, LB method (Langmuir Brodgett method, etc.)), etc. The wet method is preferred because the observed electron transport layer can be obtained efficiently.

  When the electron transport layer is formed by a wet method, the coating liquid is prepared by dissolving an electron transport material in a solvent. Whether or not X-ray diffraction lines are observed is greatly influenced by the combination of the electron transport material and the solvent, and by using a coating solution of the appropriate combination, an electron transport layer in which X-ray diffraction lines are observed is formed. be able to.

  Examples of the solvent of the coating solution for forming an electron transport layer in which X-ray diffraction lines are observed by coating include lower alcohols, fluorine alcohols, saturated hydrocarbon solvents, aromatic solvents, halogen solvents, and the like. . Specific examples include methanol, ethanol, propanol, tetrafluoropropanol, hexane, cyclohexane, toluene, dichloroethane and the like. More preferred are lower alcohols, fluorinated alcohols, and saturated hydrocarbon solvents.

  In order to observe X-ray diffraction lines in the electron transport layer formed as described above, a method of heating in a state where the solvent is removed after application of the electron transport layer is also used.

  When the electron transport layer is provided by a vacuum vapor deposition method, it is preferable to heat during or after vapor deposition in order to observe X-ray diffraction lines.

  The heating temperature varies depending on the electron transport material, but is preferably 40 ° C. or higher and 250 ° C. or lower if the substrate is glass, and preferably 40 ° C. or higher and Tg or lower of the substrate if the substrate is a resin. The heating time is preferably 10 minutes or more and 2 hours or less. If it is 10 minutes or more, the effect of extending the lifetime of the organic EL element is great, and if it is 2 hours or less, it can be efficiently produced.

  The thickness of the electron transport layer is in the range of 50 nm to 200 nm. If it is 50 nm or more, light extraction loss due to surface plasmons can be reduced, and if it is 200 nm or less, the voltage can be lowered. More preferably, it exists in the range of 50-100 nm.

  In the present invention, the electron transport layer is preferably a single material. For example, in Patent Document 2, a mixed layer of a matrix and an n-type dopant is used as an electron transport layer, and a material having a small energy difference between LUMO of the matrix and HOMO of the n-type dopant is used. However, generally used n-type dopants such as n-type dopants and lithium metal compounds described in the above-mentioned patent documents have a high oxidizing power, and therefore tend to oxidize metal electrodes. Since this causes light emission unevenness and the like, it is preferable to improve it.

  In addition, the doped layer is uniform immediately after film formation, but phase separation is likely to occur due to aging or storage at high temperature, and the carrier transport balance is lost, leading to a decrease in luminous efficiency and a decrease in lifetime.

  On the other hand, the formation of a single material is preferable because it does not cause phase separation and can achieve high mobility without using a dopant having strong oxidizing power that causes electrode oxidation.

  Further, an electron transport layer having a high n property doped with impurities can also be used.

  Hereinafter, conventionally known compounds (electron transport materials) other than the compound represented by the general formula (b) used for forming the electron transport layer of the white organic EL device of the present invention, and the general formula (1). Specific examples of the compounds are given below, but the present invention is not limited thereto.

(X-ray diffraction line)
The phrase “X-ray diffraction lines of crystal grains are observed in the electron transport layer” means that, for example, the same peak as the X-ray diffraction lines of the crystal powder is also observed in the X-ray diffraction lines of the electron transport layer. Further, when the crystal grains (regions in which the orientation and arrangement of molecules are aligned) are large, the particles are observed with an electron microscope.

  For the X-ray diffraction measurement of the electron transport layer, for example, a thin film structure evaluation apparatus ATX-G manufactured by Rigaku Corporation can be used. The measurement conditions are shown below.

  X-rays are generated with a target of copper and an output of 15 kW. Measurement is performed using a slit collimation optical system. The parallel X-rays are incident at a low angle near the total reflection critical angle, and the penetration depth of the X-rays is made equal to the film thickness.

In the X-ray diffraction measurement of the present invention, the incident angle (angle formed with the sample surface) is 0.23 °, the X-ray irradiation area is limited by the size of the slit, and the maximum irradiation area is 25 mm ^2. Adjust to.

  The incident angle is fixed, the detector is scanned at 2θ = 5 ° to 45 °, and the X-ray intensity is measured.

  FIG. 1 shows the relationship between the X-ray diffraction line of the powder and the X-ray diffraction line of the thin film (electron transport layer). X-ray diffraction lines 21, 22 and 23 shown in FIG. 1 are X-ray diffraction lines of an electron transport layer formed of the same electron transport material, 21 is an X-ray diffraction line of a thin film having no crystal grains, Reference numerals 22 and 23 denote X-ray diffraction lines of thin films with different manufacturing methods. The X-ray diffraction line 24 is an X-ray diffraction line of the same electron transport material powder. The X-ray diffraction line 23 has a peak at the same position as the X-ray diffraction line 24 of the crystal powder, but the X-ray diffraction line 22 has a different peak position. Since the position of the peak varies depending on the molecular arrangement in the crystal grains, if the molecular arrangement of the crystal grains in the powder is different from that of the crystal grains in the thin film, the peak may appear at such different positions. However, in this case as well, crystal grains are present in the thin film.

  In the electron transport layer according to the present invention, the fact that no crystal grains are contained in the X-ray diffraction measurement means that no X-ray diffraction peak is observed. Specifically, in the X-ray diffraction measurement, no diffraction peak is observed. No diffraction peak is observed when the crystallinity of the target compound in the electron transport layer is 1% or less. In that case, in this application, it defines that the electron transport layer does not contain the microcrystal grain measured by X-ray-diffraction measurement.

  The crystallinity refers to the ratio of the integrated intensity of the crystalline diffraction peak to the total X-ray scattering intensity (integrated intensity). X-ray diffraction measurement is performed at least 3 points, preferably 5 points or more, crystallinity is calculated, and crystallinity is determined based on the average.

  In the present invention, the crystallinity is preferably in the range of 1 to 15%, and if the crystallinity is in this range, the effect of the present invention appears well, and the driving voltage of the light emitting element may be kept low. Deterioration can be prevented and the storage stability of the organic EL element is good.

  The size of the crystal grains present in the layer is preferably 5 nm or less, and more preferably 1 nm or less. By making the crystal grains smaller, it prevents the formation of carrier traps due to the concentration of current in the crystal part, and prevents the generation of dark spots and device breakdown due to electric field concentration when used for a long time, thus extending the life. be able to. The size of the crystal grains can be observed with a conventionally well-known electron microscope or the like. Further, the crystal grains are preferably present uniformly in the layer.

  X-ray diffraction measurement and observation with an electron microscope are performed when the electron transport layer is formed. When heat treatment is performed after the step of the electron transport layer, the sample formed up to the electron transport layer is similarly heat treated, and then measurement and observation are performed.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (vi) anode / hole transport layer / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (vii) anode / anode buffer Layer / hole transport layer / light emitting layer / electron transport layer / cathode buffer layer / cathode The light emitting layer may form a unit to form a light emitting layer unit.

  Further, a non-light emitting intermediate layer may be provided between the light emitting layers, and the intermediate layer may include a charge generation layer. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 5 nm to 100 nm.

  For the production of the light emitting layer, a light emitting dopant or host compound described later is used, for example, a vacuum deposition method, a wet method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, An ink-jet method, a printing method, a spray coating method, a curtain coating method, an LB method (a Langmuir-Blodgett method and the like can be used)) and the like can be formed. When using the compound of this invention for a light emitting layer, producing by a wet process is preferable.

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant, phosphorescent dopant group) or fluorescent dopant) compound and a light emitting host compound. Is preferred.

(Luminescent dopant compound)
A light-emitting dopant compound (also referred to as a light-emitting dopant) will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used.

(Phosphorescent dopant (also called phosphorescent dopant))
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant compound according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of the phosphorescent dopant in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the luminescent host compound, and this energy is used as the phosphorescent dopant. The energy transfer type in which light emission from the phosphorescent dopant is obtained by moving to the other, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound occurs. In any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

  Moreover, you may use together the compound etc. which are described in the following patent gazettes in the light emitting layer which concerns on this invention.

  For example, International Publication No. 00/70655 pamphlet, JP 2002-280178 A, JP 2001-181616 A, JP 2002-280179 A, JP 2001-181617 A, JP 2002-280180 A. JP, 2001-247859, JP, 2002-299060, JP, 2001-313178, JP, 2002-302671, JP, 2001-345183, JP, 2002-324679, International, Publication No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-117978, JP 2002-338588, JP 2002-170684, JP 2002-352960, WO 01/93642, JP 2002-50483, JP 2002-1000047, JP JP 2002-173684 A, JP 2002-359082 A, JP 2002-17584 A, JP 2002-363552 A, JP 2002-184582 A, JP 2003-7469 A, Special Table 2002. No. 525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-233506 Gazette, JP2002-24175 JP, JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, 2002-343572. JP-A-2002-203678.

(Fluorescent dopant (also called fluorescent compound))
Fluorescent dopants include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes , Polythiophene dyes, rare earth complex phosphors, and the like, and compounds having a high fluorescence quantum yield such as laser dyes.

  In addition, the light-emitting dopant according to the present invention may be used in combination of a plurality of types of compounds, or may be a combination of phosphorescent dopants having different structures, or a combination of a phosphorescent dopant and a fluorescent dopant.

  As a dopant compound, the compound represented by the following general formula (a) is preferable.

一般式（ａ）において、Ｒ_１は置換基を表す。ＺはＣ−Ｂ_０と共に５〜７員環を形成するのに必要な非金属原子群を表す。ｎ１は０〜５の整数を表す。Ｂ_０は炭素原子又は窒素原子を表し、Ｂ_１〜Ｂ_５はＣ（Ｒ_１１）、Ｎ、Ｎ（Ｒ_１１）、Ｓ、Ｃ（Ｒ_１１）＝Ｃ（Ｒ_１２）、Ｃ（Ｒ_１１）＝Ｎ、又はＮ＝Ｎを表し、Ｂ_１〜Ｂ_５が共に形成する環は少なくとも一つ窒素原子を有し、単環の芳香族含窒素複素環を表す。Ｒ_１１及びＲ_１２は水素原子又は置換基を表す。Ｍ_１は元素周期表における８〜１０族の金属を表す。Ｘ_１及びＸ_２は炭素原子、窒素原子又は酸素原子を表し、Ｌ_１はＸ_１及びＸ_２と共に２座の配位子を形成する原子群を表す。ｍ１は１〜３の整数を表し、ｍ２は０〜２の整数を表すが、ｍ１＋ｍ２は２又は３である。Ｒ_１、Ｒ_１１及びＲ_１２で表される置換基としては、前記一般式（１）のＡｒ_１〜Ａｒ_３が有していてもよい置換基と同義の置換基が挙げられる。ｍ１が２以上の場合、ＺがＣ−Ｂ_０と共に形成する５〜７員環及びＢ_１〜Ｂ_５が共に形成する芳香族含窒素複素環は同じでも異なっていてもよい。

In the general formula (a), R ₁ represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring with C—B ₀ . n1 represents the integer of 0-5. B ₀ represents a carbon atom or a nitrogen atom, and B _{1 to} B ₅ are C (R ₁₁ ), N, N (R ₁₁ ), S, C (R ₁₁ ) = C (R ₁₂ ), C (R ₁₁ ) = N or N = N, and the ring formed by B _{1 to} B ₅ together has at least one nitrogen atom, and represents a monocyclic aromatic nitrogen-containing heterocyclic ring. R ₁₁ and R ₁₂ represent a hydrogen atom or a substituent. M ₁ represents a group 8-10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom, or an oxygen atom, and L ₁ represents an atomic group that forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 is 2 or 3. Examples of the substituent represented by R ₁ , R _11, and R ₁₂ include a substituent having the same meaning as the substituent that Ar _{1 to} Ar ₃ of the general formula (1) may have. When m1 is 2 or more, the 5- to 7-membered ring formed by Z together with C—B ₀ and the aromatic nitrogen-containing heterocycle formed by B _{1 to} B ₅ may be the same or different.

In the general formula (a), the aromatic hydrocarbon ring formed by Z together with B ₀ -C includes a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, and a naphthacene ring. , Triphenylene ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring , Pyrene ring, pyranthrene ring, anthraanthrene ring and the like.

  These rings may further have a substituent, and the substituents may form a ring.

In the general formula (a), the aromatic heterocycle formed by Z together with B ₀ -C includes a furan ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, Benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, azacarbazole A ring etc. are mentioned.

  Here, the azacarbazole ring refers to one in which one or more carbon atoms constituting the carbazole ring are replaced with a nitrogen atom.

These rings may further have a substituent. Examples of the substituent include a substituent having the same meaning as the substituent that Ar _{1 to} Ar ₃ of the general formula (1) may have.

In the general formula (a), the rings formed by B _{1 to} B ₅ together include a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazine ring, an oxazole ring, an oxadiazole ring, an oxatriazole ring, an isoxazole ring, and a tetrazole ring. , Thiadiazole ring, thiatriazole ring, isothiazole ring, pyrrole ring, imidazole ring, pyrazole ring, triazole ring and the like. A ring containing two or more nitrogen atoms is preferable, and an imidazole ring is more preferable.

These rings may further have a substituent, and the substituents may form a ring. Furthermore, R ₁ and R ₁₁ or R ₁₂ may combine to form a ring.

In the general formula (a), specific examples of the bidentate ligand represented by X ₁ -L ₁ -X ₂ include phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, acetylacetone, Examples include picolinic acid.

  In the general formula (a), m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 represents 2 or 3. Among these, a case where m2 is 0 is preferable.

In the general formula (a), M ₁ is a transition metal element of group 8 to group 10 (also simply referred to as a transition metal) in the periodic table, and is preferably iridium.

  The compound represented by the general formula (a) is more preferably a compound represented by the following general formula (a2).

一般式（ａ２）において、Ｒ_１、Ｚ、Ｂ_０〜Ｂ_５、Ｍ_１、Ｘ_１、Ｘ_２、Ｌ_１、ｎ１、ｍ１及びｍ２は、前記一般式（ａ）のＲ_１、Ｚ、Ｂ_０〜Ｂ_５、Ｍ_１、Ｘ_１、Ｘ_２、Ｌ_１、ｎ１、ｍ１及びｍ２と同義である。Ｒ１３は置換基を表す。Ｒ_１３で表される置換基としては、前記一般式（１）のＡｒ_１〜Ａｒ_３が有していてもよい置換基と同義の置換基が挙げられる。

In the general formula (a2), R ₁ , Z, B _{0 to} B ₅ , M ₁ , X ₁ , X ₂ , L ₁ , n 1, m 1 and m 2 are R ₁ , Z, B in the general formula (a). ₀ .about.B _5, an _{M 1, X 1, X 2} , L 1, n1, synonymous with m1 and m @ 2. R13 represents a substituent. Examples of the substituent represented by R ₁₃ include a substituent having the same meaning as the substituent that Ar _{1 to} Ar ₃ of the general formula (1) may have.

  Specific examples of phosphorescent dopant compounds that can be preferably used in the present invention are given below. Of course, the present invention is not limited to these.

(Luminescent host compound (also referred to as luminescent host))
In the present invention, the host compound has a mass ratio of 20% or more among the compounds contained in the light emitting layer, and a phosphorescence quantum yield of phosphorescence emission is 0 at room temperature (25 ° C.). Defined as less than 1 compound. The phosphorescence quantum yield is preferably less than 0.01.

  There is no restriction | limiting in particular as a light emission host which can be used for this invention, The compound conventionally used with an organic EL element can be used. Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As the luminescent host that can be used in the present invention, the compound represented by the general formula (b) is preferable, and the compound represented by the general formula (b) is a 6-membered member containing at least one nitrogen atom in the molecule. More preferably, the aromatic heterocycle or a condensed ring having a 6-membered aromatic heterocycle containing at least one nitrogen atom as one of the rings constituting the condensed ring is not included.

  More preferably, the light emitting host is a compound represented by the general formula (b3) or (b4), and the general formula (b3-1), (b3-2), (b4-1) or (b4-2). It is further more preferable that it is a compound represented by these.

  As the known light-emitting host that can be used in the present invention, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from becoming longer, and has a high Tg (glass transition temperature) is preferable. More preferably, Tg is 100 ° C. or higher.

  By using a plurality of types of light-emitting hosts, the movement of charges can be adjusted, and the organic EL element can be made highly efficient.

  Moreover, it becomes possible to mix different light emission by using multiple types of well-known compounds used as the said phosphorescence dopant, and, thereby, arbitrary luminescent colors can be obtained.

  In addition, the light emitting host used in the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (polymerizable light emitting host). Of course, one or a plurality of such compounds may be used.

  Specific examples of the known light-emitting host include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Specific examples of conventionally known compounds and compounds represented by the general formula (b) used as the light-emitting host of the light-emitting layer of the organic EL device of the present invention (compounds 1 to 95 listed as specific examples of the electron transport material) The present invention is not limited to these examples.

《Hole transport layer》
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material as described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can.

  Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, it exists in the range of 5 nm-5 micrometers, Preferably it exists in the range of 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

  Hereinafter, although the specific example of the compound preferably used for formation of the positive hole transport layer of the organic EL element of this invention is given, this invention is not limited to these.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the electron carrying layer of this invention can be used as a hole-blocking layer as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  In the hole blocking layer, the compound represented by the general formula (b), the carbazole derivative, and the azacarbazole derivative (herein, the azacarbazole derivative is the carbon atom constituting the carbazole ring). One or more of which are replaced by nitrogen atoms).

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

  The ionization potential is defined by the energy required to emit electrons at the HOMO (highest occupied orbital) level of the compound to the vacuum level, and can be determined by, for example, the following method.

  (1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA As a value (eV unit converted value) calculated by performing structure optimization using B3LYP / 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  (2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the above-mentioned hole transport layer can be used as an electron blocking layer as needed. The film thicknesses of the hole blocking layer and the electron blocking layer according to the present invention are preferably in the range of 3 nm to 100 nm, and more preferably in the range of 3 nm to 30 nm.

<< Injection layer: electron injection layer (cathode buffer layer), hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166), and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by, alkali metal compound buffer layer typified by lithium fluoride, sodium fluoride and potassium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, and aluminum oxide And an oxide buffer layer. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

  In addition, the materials used for the anode buffer layer and the cathode buffer layer can be used in combination with other materials. For example, the materials can be mixed in the hole transport layer or the electron transport layer.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO.

Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. The anode may be formed by depositing a thin film of these electrode materials by vapor deposition or sputtering, and a pattern having a desired shape may be formed by photolithography, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected within the range of 10 nm to 1000 nm, preferably within the range of 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like.

Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. Further, the sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably in the range of 50 nm to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  In addition, a transparent or semi-transparent cathode is produced by producing a conductive transparent material mentioned in the description of the anode on the cathode after producing the metal with a film thickness in the range of 1 nm to 20 nm. By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC), cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

An inorganic film, an organic film, or a hybrid film of both may be formed on the surface of the resin film, and the water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

  Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Method for Manufacturing Organic EL Element >>
As an example of a method for producing an organic EL device, a device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection layer) / cathode Will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate so as to have a film thickness of 1 μm or less, preferably in the range of 10 nm to 200 nm, thereby producing an anode.

  Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, or a cathode buffer layer, which is an element material, is formed thereon.

  In the phosphorescent organic EL device of the present invention, it is preferable that at least the cathode and the electron transport layer adjacent to the cathode are applied and formed by a wet method.

  Wet methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but precise thin films can be formed. In view of high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, or a spray coating method is preferable. Different film forming methods may be applied for each layer.

  Examples of the liquid medium for dissolving or dispersing the organic EL material other than the electron transport material contained in the electron transport layer according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, dichlorobenzene, and the like. Halogenated hydrocarbons, aromatic hydrocarbons such as toluene, xylene, mesitylene and cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin and dodecane, and organic solvents such as DMF and DMSO can be used.

  Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After the formation of these layers, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a desired organic EL device can be obtained by providing a cathode. .

  Further, the order can be reversed, and the cathode, cathode buffer layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed in this order.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage in the range of 2 V to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  The organic EL device of the present invention is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is preferable to perform the work in a dry inert gas atmosphere.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, transparency and electrical insulation are not particularly limited.

  Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.

  Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

  In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can.

  Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

  In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (with a refractive index in the range of 1.7 to 2.1), and light of about 15% to 20% of the light generated in the light emitting layer. It is generally said that it can only be taken out. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally in the range of 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Of these, light that cannot go out due to total reflection between layers, etc. is diffracted by introducing a diffraction grating into any layer or medium (inside a transparent substrate or transparent electrode). I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any one of the layers or in the medium (in the transparent substrate or the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably in the range of about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL element of the present invention can be processed on a light extraction side of a substrate, for example, by providing a microlens array-like structure, or combined with a so-called condensing sheet, for example in a specific direction, for example, with respect to the element light emitting surface. By condensing in the front direction, the luminance in a specific direction can be increased.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably within a range of 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.

  As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

  In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the device may be patterned. Can do.

  The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (Konica Minolta Sensing Co., Ltd.) is applied to the CIE chromaticity coordinates.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device of the present invention will be described. The display device of the present invention comprises the organic EL element of the present invention.

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.

  Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  When a DC voltage is applied to the obtained multicolor display device, light emission can be observed by applying a voltage in the range of 2V to 40V with the anode as + and the cathode as-polarity. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. The present invention is not limited to these examples.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 2 is a schematic view showing an example of a display device composed of organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of a plurality of pixels based on image information from the outside. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 3 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the drawing, the light L emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning line 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data.

  Full-color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 4 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 4, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels, and light emission of the organic EL element 10 of each of the plurality of pixels 3. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good. The potential of the capacitor 13 may be maintained until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 5 is a schematic diagram of a passive matrix display device. In FIG. 5, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal.

  In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element.

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However, It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display).

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, it is possible to produce a full-color display device by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.

  According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode to be in close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and as shown in FIG. 6 and FIG. Can be formed.

  FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  7 shows a cross-sectional view of the lighting device. In FIG. 7, reference numeral 104 denotes an electron transport layer, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  Hereinafter, the present invention will be described in detail by way of examples. When the symbols of the compounds used in the examples coincide with the symbols of the specific examples of the compounds described in `` Mode for carrying out the invention '', This specific example is meant.

Example 1
<< Production of organic EL element >>
[Production of Organic EL Element 101 (Comparative Example)]
After patterning a 120 nm-thick ITO (indium tin oxide) substrate on a 30 mm × 30 mm × 0.7 mm glass substrate as an anode, the substrate provided with this ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Then, it was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron PAl 4083) to 70% with pure water on this substrate is spun at 3000 rpm for 30 seconds. Then, the film was dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole injection layer.

This substrate was transferred to a glove box under a nitrogen atmosphere in accordance with JIS B9920 with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or lower, and an oxygen concentration of 0.8 ppm. A coating solution for a hole transport layer was prepared as follows in a glove box, and applied with a spin coater under conditions of 1500 rpm and 30 seconds. This substrate was heated at 150 ° C. for 10 seconds, and irradiated with 30 mW / cm ² of ultraviolet light for 20 seconds using a high pressure mercury lamp (OHD-110M-ST, manufactured by Oak Manufacturing Co., Ltd.). Furthermore, it heated at 120 degreeC for 30 minute (s), and provided the positive hole transport layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for hole transport layer)
Toluene 100g
HT-30 0.45g
HT-31 0.05g
Subsequently, the light emitting layer coating liquid was prepared as follows, and it apply | coated on the conditions which raise from 500 rpm to 5000 rpm in 30 seconds with a spin coater. Furthermore, it heated at 150 degreeC for 30 minutes, and provided the light emitting layer. The film thickness was 40 nm when it applied and measured on the board | substrate prepared separately on the same conditions.

(Light emitting layer coating solution)
Toluene 100g
H-25 1g
D-26 0.11g
Next, an electron transport layer coating solution was prepared as described below, and applied with a spin coater under conditions of 700 rpm and 30 seconds.

Separately, an electron transport layer was provided on the prepared substrate in the same manner as described above. The crystallinity is calculated by X-ray diffraction measurement at five points near the center of the substrate, and the average of the five points is 0.5%. The X-ray diffraction peak due to crystal grains in the electron transport layer Was not detected. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).
The film thickness was 55 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for electron transport layer)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-9 0.9g
Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. Note that cesium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.

  First, a resistance heating boat containing cesium fluoride was energized and heated, and an electron injection layer made of cesium fluoride was provided with a thickness of 3 nm on the substrate. Subsequently, a resistance heating boat containing aluminum was energized and heated, and a cathode having a thickness of 100 nm made of aluminum was provided within a range of a deposition rate of 1 to 2 nm / second to produce an organic EL element 101.

  When evaluating the obtained organic EL element 101, the cleanliness measured in accordance with JIS B9920 in a nitrogen atmosphere without exposing the substrate provided up to the cathode to the atmosphere is class 100, and the dew point temperature is −80 ° C. or lower. Move to a glove box with an oxygen concentration of 0.8 ppm, cover the non-light emitting surface of the organic EL element 101 with a glass cover, and seal the glass cover and the glass substrate side on which the organic EL element is made to contact An epoxy-based photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) is applied as an agent, and this is superimposed on the cathode side to be in close contact with the transparent support substrate and cured by irradiating UV light from the glass substrate side. Then, the lighting device as shown in FIGS. 6 and 7 was formed and evaluated.

  As a water replenisher, a high-purity barium oxide powder made by Aldrich was attached in advance to a glass sealing can with a fluorine-based semipermeable membrane (Microtex S-NTF8031Q, manufactured by Nitto Denko) with an adhesive. Used.

[Production of Organic EL Element 102 (Comparative Example)]
In the production of the organic EL element 101, an organic EL element 102 was produced in the same manner except that an electron transport layer was provided by the following procedure.

  An electron transport layer coating solution was prepared as follows, and applied with a spin coater under the conditions of 1000 rpm and 30 seconds. Furthermore, it heated at 110 degreeC for 30 minutes, and provided the electron carrying layer.

  A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. The crystallinity was calculated by X-ray diffraction measurement at five points near the center of the substrate, and the average of the five points was 12%. An X-ray diffraction peak due to crystal grains was detected in the electron transport layer. It was. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  The film thickness was 45 nm when it applied and measured on the conditions prepared with the board | substrate prepared separately.

(Coating liquid for electron transport layer)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-9 0.9g
[Production of Organic EL Elements 103 to 108 (Invention)]
In the production of the organic EL element 102, the electron transport layer material is changed to the material shown in Table 1, and the film thickness is changed to the film thickness shown in Table 1 by changing the concentration of the electron transport layer coating solution and the rotation speed of the spin coater. Organic EL elements 103 to 108 were produced in the same manner as the organic EL element 102 except for the change. Compound 85 is a compound selected from the specific examples of the compound represented by formula (b).

  Table 1 shows the results of determining the presence or absence of crystal grains in the electron transport layer by X-ray diffraction measurement in the same manner as in the production of the organic EL element 102. Subsequently, evaluation was performed according to the following measurement method.

<< Formation of lighting device including organic EL elements 102-108 >>
When the obtained organic EL elements 102 to 108 were evaluated, they were sealed in the same manner as the organic EL element 101, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

<< Evaluation of Organic EL Elements 101-108 >>
(External quantum efficiency)
The organic EL element is allowed to emit light at room temperature (within a range of about 23 ° C. to 25 ° C.) and a constant current of ^2.5 mA / cm ² , and light emission luminance (L) [cd / m ² ] immediately after the start of light emission is measured. Thus, the external extraction quantum efficiency (η) was calculated.

  Here, CS-1000 (manufactured by Konica Minolta Sensing) was used for measurement of light emission luminance. The external extraction quantum efficiency is expressed as a relative value where the organic EL element 101 is 100.

(Drive voltage)
Each voltage was measured when the organic EL element was driven at room temperature (within a range of about 23 ° C. to 25 ° C.) and a constant current of ^2.5 mA / cm ^2. The results are shown in Table 1 below.

(Luminescent life)
The organic EL device continuously emitted light at room temperature under a constant current condition of ^2.5 mA / cm ² , and the time (τ1 / 2) required to obtain half the initial luminance was measured. The light emission lifetime is expressed as a relative value of τ1 / 2 of each organic EL element, where τ1 / 2 of the organic EL element 101 is 100.

表１より、本発明の有機ＥＬ素子は、駆動電圧が低く、発光寿命が改善されていることが分かる。特に本発明の中でも、一般式（ｂ）の化合物８５を用いた素子１０６は取り出し効率が高く、発光寿命が長いことが分かる。

From Table 1, it can be seen that the organic EL device of the present invention has a low driving voltage and an improved light emission lifetime. In particular, among the present invention, it can be seen that the element 106 using the compound 85 of the general formula (b) has high extraction efficiency and a long emission lifetime.

Example 2
<< Production of Organic EL Element 201 >>
[Production of Organic EL Element 201]
After patterning a 120 nm-thick ITO (indium tin oxide) substrate on a 30 mm × 30 mm × 0.7 mm glass substrate as an anode, the substrate provided with this ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Then, it was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron PAl 4083) to 70% with pure water on this substrate is spun at 3000 rpm for 30 seconds. Then, the film was dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole injection layer.

  This substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of HT-2 is put in a molybdenum resistance heating boat, and 200 mg of Host-16 as a host compound is put in another resistance heating boat made of molybdenum. 100 mg of D-48 was added as a dopant compound to a resistance heating boat made of molybdenum, and the compound 86 (selected from the specific example of the compound represented by the general formula (b) was selected as a host of the electron transport layer in another resistance heating boat made of molybdenum. 200 mg of the compound) was added, and 200 mg of cesium carbonate as an electron transport layer dopant was added to another molybdenum resistance heating boat and attached to a vacuum deposition apparatus.

Next, the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, and then the heating boat containing HT-2 was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. A transport layer was provided.

  Further, the heating boat containing Host-16 and D-48 was energized and heated, and co-evaporated on the hole transport layer at a deposition rate of 0.1 nm / sec and 0.006 nm / sec, respectively, to emit light of 20 nm. A layer was provided.

  Further, the heating boat containing the compound 86 and cesium carbonate was heated by energization, and deposited on the light emitting layer at a deposition rate of 0.15 nm / sec and 0.001 nm / sec, respectively, to form an electron transport layer having a thickness of 80 nm. Provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Separately, an electron transport layer was provided on the prepared substrate in the same manner as described above. The crystallinity is calculated by X-ray diffraction measurement at three points near the center of the substrate, and the average of the three points is 0.7%. The X-ray diffraction peak due to crystal grains in the electron transport layer Was not detected. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  Subsequently, lithium fluoride 0.5 nm was vapor-deposited as a cathode buffer layer, and aluminum 110 nm was vapor-deposited to form a cathode, whereby an organic EL element 201 was produced.

[Production of Organic EL Element 202]
In the organic EL element 201, an organic EL element 202 was formed in the same manner as the organic EL element 201 except that the electron transport layer was prepared as follows.

  After forming the light emitting layer, the heating boat containing ET-12 and the electron transport dopant 1 shown below is energized and heated, and the deposition rate is 0.1 nm / sec and 0.006 nm / sec on the light emitting layer, respectively. And an electron transport layer having a thickness of 60 nm was provided.

  A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. The crystallinity was calculated by measuring X-ray diffraction at three points near the center of the substrate, and the average of the three points was 0.3%. In the electron transport layer, X-ray diffraction peaks due to crystal grains Was not detected. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

次いで、有機ＥＬ素子２０１と同様に陰極バッファー層、陰極を形成し、有機ＥＬ素子２０２を形成した。

Next, a cathode buffer layer and a cathode were formed in the same manner as the organic EL element 201, and an organic EL element 202 was formed.

[Production of Organic EL Element 203]
After forming to the cathode similarly to the organic EL element 201, it heat-processed at 120 degreeC for 15 minutes, and the organic EL element 203 was obtained.

  In the same manner as described above, a separately prepared substrate was provided up to the electron transport layer, and heat-treated at 120 ° C. for 15 minutes. The crystallinity is calculated by measuring X-ray diffraction at three points near the center of the substrate, and the average of the three points is 5%. An X-ray diffraction peak due to crystal grains is detected in the electron transport layer. It was. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

[Production of Organic EL Element 204]
After forming to a cathode similarly to the organic EL element 202, it heat-processed at 120 degreeC for 15 minutes, and the organic EL element 204 was obtained.

  In the same manner as described above, a separately prepared substrate was provided up to the electron transport layer, and heat-treated at 120 ° C. for 15 minutes. The crystallinity is calculated by measuring X-ray diffraction at three points near the center of the substrate, and the average of the three points is 2%. An X-ray diffraction peak due to crystal grains is detected in the electron transport layer. It was. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

[Production of organic EL elements 205 to 212]
In the production of the organic EL element 204, the electron transport layer material and the host compound were changed to the materials shown in Table 2, and the film thickness was changed to the film thickness shown in Table 2 by changing the deposition time. In the same manner, organic EL elements 205 to 212 were produced. In each of the elements 207 to 210 and 212, a compound selected from specific examples of the compound example represented by the general formula (b) was used as a host of the light emitting layer. The confirmation of the crystal grains in the electron transport layer was performed in the same manner as the organic EL element 204. Table 2 shows the results of determination of the presence or absence of crystal grains in the electron transport layer.

[Evaluation of Organic EL Elements 201-212]
When the obtained organic EL elements 201 to 212 were evaluated, they were sealed in the same manner as the organic EL element 101 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

[Evaluation of storage stability]
After storing each organic EL element in a 70 ° C. environment for 200 hours and then driving at a constant current value of ^2.5 mA / cm ² , the power efficiency retention rate (70% when the power efficiency when untreated is 100%) Power efficiency ratio after storage at 200 ° C. for 200 hours), drive life retention ratio (life ratio after storage for 200 hours at 70 ° C. when the lifetime when not processed is 100%), and luminance unevenness, This was a measure of the storage stability of the organic EL device. The driving life was obtained by the same method as in Example 1.

In addition, the luminance unevenness is evaluated as ◯ when the luminance difference between the maximum luminance and the minimum luminance in the light emitting surface when driven at a constant current value of ^2.5 mA / cm ² is 15% or less with respect to the maximum luminance. When it was larger than%, it was set as x.

For luminance measurement, the front luminance of each organic EL element was measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing). When measuring the driving lifetime, the luminance fluctuation during continuous driving was measured with the front luminance of 2000 cd / m ² as the initial luminance, and the luminance half time was determined as the driving lifetime.

表２より、本発明の有機ＥＬ素子は電力効率変化率の低下幅が小さく、駆動寿命に優れていることが分かる。また本発明の中でも、電子輸送材料として一般式（ｂ）の化合物を用いた場合は、電力効率の低下が小さく、駆動寿命の低下が小さいことが分かる。

From Table 2, it can be seen that the organic EL element of the present invention has a small decrease in the power efficiency change rate and is excellent in driving life. In the present invention, when the compound of the general formula (b) is used as the electron transport material, it can be seen that the decrease in power efficiency is small and the decrease in driving life is small.

Example 3
<< Production of organic EL element >>
[Production of Organic EL Element 301]
After patterning a 120 nm-thick ITO (indium tin oxide) substrate on a 30 mm × 30 mm × 0.7 mm glass substrate as an anode, the substrate provided with this ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Then, it was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron PAl 4083) to 70% with pure water on this substrate is spun at 3000 rpm for 30 seconds. Then, the film was dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole injection layer.

  This substrate was transferred to a glove box under a nitrogen atmosphere in accordance with JIS B9920 with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or lower, and an oxygen concentration of 0.8 ppm. A hole transport layer coating solution was prepared as follows in a glove box, and applied with a spin coater under conditions of 2500 rpm and 30 seconds. Furthermore, it heated at 120 degreeC for 30 minute (s), and provided the positive hole transport layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for hole transport layer)
Dichlorobenzene 100g
ADS254BE (American Dye Source, Inc.) 0.5g
This substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while Compound Example 14 (a compound example represented by the general formula (b) is used as a host compound for another resistance heating boat made of molybdenum and another resistance heating boat made of molybdenum. 200 mg), 100 mg of D-9 as a dopant compound was placed in another molybdenum resistance heating boat, and attached to a vacuum deposition apparatus.

Then, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing Compound Example 14 and D-9 was energized and heated, and the deposition rates were 0.1 nm / sec and 0.006 nm / sec, respectively. A 20 nm light emitting layer was provided by co-evaporation on the hole transport layer.

  Next, this substrate was again transferred to a glove box in accordance with JIS B9920 under a nitrogen atmosphere, the measured cleanliness was class 100, the dew point temperature was −80 ° C. or less, and the oxygen concentration was 0.8 ppm. Then, an electron transport layer coating solution was prepared as follows, and applied with a spin coater at 700 rpm for 30 seconds.

  A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. X-ray diffraction measurement was performed at five points near the center of the substrate, the degree of crystallinity was calculated, and the average of the five points was 0.5%. The X-ray diffraction peak due to crystal grains in the electron transport layer Was not detected. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  The film thickness was 60 nm when it applied and measured on the conditions prepared on the board | substrate prepared separately.

(Coating liquid for electron transport layer)
1-butanol 100g
ET-13 1g
Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. Note that lithium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.

  First, a resistance heating boat containing lithium fluoride was energized and heated to provide 3 nm of an electron injection layer made of lithium fluoride on the substrate. Subsequently, a resistance heating boat containing aluminum was energized and heated, and a cathode having a thickness of 100 nm made of aluminum was provided within a range of a deposition rate of 1 to 2 nm / second to produce an organic EL element 301.

[Production of Organic EL Element 302]
An organic EL element 302 was produced in the same manner except that 2,2,3,3-tetrafluoro-1-propanol was used instead of 1-butanol in the production of the organic EL element 301. The confirmation of the crystal grains in the electron transport layer was performed by the same method as that for the organic EL element 301. Table 2 shows the results of determination of the presence or absence of crystal grains in the electron transport layer.

[Production of organic EL elements 303 to 308]
In the production of the organic EL element 302, the electron transport layer material is changed to the material shown in Table 3, and the film thickness is changed to the film thickness shown in Table 3 by changing the concentration of the electron transport layer coating solution and the rotation speed of the spin coater. Organic EL elements 303 to 308 were produced in the same manner as the organic EL element 302 except that the changes were made. The confirmation of the crystal grains in the electron transport layer was performed by the same method as that for the organic EL element 301. Table 2 shows the results of determination of the presence or absence of crystal grains in the electron transport layer.

<< Evaluation of Organic EL Elements 301-308 >>
When the obtained organic EL elements 301 to 308 were evaluated, they were sealed in the same manner as the organic EL element 101 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

(Power efficiency)
Using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.), the front luminance and luminance angle dependency of each organic EL element were measured, and the power efficiency at a front luminance of 1000 cd / m ² was obtained. The power efficiency was expressed as a relative value when the power efficiency of the organic EL element 301 was set to 100.

(Voltage increase rate)
When driving at a constant current of 6 mA / cm ² , the initial voltage and the voltage after 150 hours were measured. The relative value of the voltage after 150 hours with respect to the initial voltage 100 was defined as the voltage increase rate.

(Luminescent life)
The light emission lifetime was evaluated by the same method as in Example 1.

表３より、本発明の有機ＥＬ素子は電力効率が高く、発光寿命が長いことが分かる。本発明の中でも、一般式（ｂ）の化合物を用いた有機ＥＬ素子は発光寿命が特に長いことが分かる。

From Table 3, it can be seen that the organic EL device of the present invention has high power efficiency and a long emission lifetime. Among the present inventions, it can be seen that the organic EL device using the compound of the general formula (b) has a particularly long emission lifetime.

Example 4
<< Production of White Organic EL Element 401 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. Then, the film was formed by spin coating and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was spin-coated on the hole transport layer at 2500 rpm for 30 seconds, and a thin film was formed. Formed. It vacuum-dried at 60 degreeC for 1 hour, and formed the 2nd positive hole transport layer.

  Next, using a solution in which HOST-54 (100 mg), D-6 (0.5 mg), and D-48 (16 mg) are dissolved in 10 ml of butyl acetate, a film is formed by spin coating under conditions of 1000 rpm and 30 seconds. did. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer.

  Using a solution obtained by dissolving Compound 88 (40 mg) in 1 ml of 1-butanol hexafluoroisopropanol (HFIP), an electron transport layer was formed by spin coating under conditions of 500 rpm and 30 seconds.

  In the same manner as described above, an electron transport layer was provided on a separately prepared substrate, and X-ray diffraction measurement was performed. As a result, X-ray diffraction lines were observed, and crystal grains were confirmed. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  The film thickness was 60 nm when it applied and measured on the conditions prepared on the board | substrate prepared separately.

Subsequently, this substrate was fixed to a substrate holder of a vacuum vapor deposition apparatus, 200 mg of ET-7 was placed in a molybdenum resistance heating boat, and was attached to the vacuum vapor deposition apparatus. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, heating by energizing the heating boat containing ET-7, vapor deposition on the electron transport layer at a deposition rate of 0.1 nm / second, A second electron transport layer having a thickness of 20 nm was provided. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Subsequently, 0.5 nm of potassium fluoride and 110 nm of aluminum were deposited to form a cathode, and an organic EL element 401 was produced.

  About the obtained organic EL element 401, it sealed similarly to the organic EL element 101 of Example 1, and formed the illuminating device as shown in FIG. 6, FIG.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 5
<< Preparation of White Organic EL Element 501 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. Then, the film was formed by spin coating and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of commercially available ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of toluene was spin-coated on the hole transport layer at 2500 rpm for 30 seconds, and a thin film was formed. Formed. It vacuum-dried at 60 degreeC for 1 hour, and formed the 2nd positive hole transport layer.

  Next, using a solution in which HOST-55 (100 mg), D-26 (20 mg), D-1 (0.5 mg), and D-10 (0.1 g) were dissolved in 10 ml of butyl acetate, 1500 rpm, 30 seconds. The film was formed by spin coating under the conditions. It vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer.

  This substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of compound 89 is placed as an electron transport material in a resistance heating boat made of molybdenum, and 50 mg of cesium fluoride is placed in another resistance heating boat made of molybdenum. Attached to.

Next, the pressure in the vacuum chamber was reduced to 4 × 10 ⁻⁴ Pa, and the heating boat containing the compound 89 was heated by heating. The film was deposited on the light emitting layer at a deposition rate of 0.1 nm / sec. The first electron transport layer was provided by heating for 30 minutes. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  A substrate prepared separately was provided up to the first electron transport layer in the same manner as described above. When X-ray diffraction measurement was performed at five points near the center of the substrate, the degree of crystallinity was calculated, and the average of the five points was 7%. An X-ray diffraction peak due to crystal grains was detected in the electron transport layer. It was. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  Further, when the substrate temperature was returned to room temperature, the heating boat containing compound 89 and cesium fluoride was energized and heated, and the first electron transport layer was deposited at a deposition rate of 0.15 nm / sec and 0.001 nm / sec, respectively. The second electron transport layer having a thickness of 5 nm was provided by vapor deposition.

  Subsequently, cesium fluoride 0.5 nm was deposited as a cathode buffer layer, and aluminum 110 nm was further deposited to form a cathode, whereby an organic EL element 501 was produced.

  About the obtained organic EL element 501, it sealed similarly to the organic EL element 101, and formed the illuminating device as shown in FIG. 6, FIG. When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 6
<< Preparation of White Organic EL Element 601 >>
After patterning a 120 nm-thick ITO (indium tin oxide) substrate on a 30 mm × 30 mm × 0.7 mm glass substrate as an anode, the substrate provided with this ITO transparent electrode was ultrasonically cleaned with isopropyl alcohol. Then, it was dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. A solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron PAl 4083) to 70% with pure water on this substrate is spun at 3000 rpm for 30 seconds. Then, the film was dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole injection layer.

This substrate was transferred to a glove box under a nitrogen atmosphere in accordance with JIS B9920 with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or lower, and an oxygen concentration of 0.8 ppm. A coating solution for a hole transport layer was prepared as follows in a glove box, and applied with a spin coater under the conditions of 2000 rpm and 30 seconds. This substrate was heated at 150 ° C. for 10 seconds, and irradiated with 30 mW / cm ² of ultraviolet light for 20 seconds using a high pressure mercury lamp (OHD-110M-ST, manufactured by Oak Manufacturing Co., Ltd.). Furthermore, it heated at 120 degreeC for 30 minute (s), and provided the positive hole transport layer. The film thickness was 15 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for hole transport layer)
Toluene 100g
HT-30 0.50g
Next, a light emitting layer coating solution was prepared as described below, and applied with a spin coater under conditions of 1500 rpm and 30 seconds. Furthermore, it heated at 150 degreeC for 30 minutes, and provided the 1st light emitting layer. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Light emitting layer coating solution)
Toluene 100g
Compound Example 18 5g
D-3 0.03g
D-10 0.008g
This substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of Compound Example 17 is placed as a host compound in a molybdenum resistance heating boat, and 100 mg of D-50 as a dopant compound is placed in another molybdenum resistance heating boat. In another resistance heating boat made of molybdenum, 200 mg of ET-14 as a first electron transporting material and 200 mg of compound 90 as a second electron transporting material were placed in a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing Compound Example 17 and D-50 was energized and heated, and the deposition rates were 0.1 nm / sec and 0.015 nm / sec, respectively. A 20 nm light emitting layer was provided by co-evaporation on the hole transport layer. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Next, with the substrate temperature heated to 60 ° C., the heating boat containing ET-14 and compound 90 was energized and heated, and the light emitting layer was deposited at a deposition rate of 0.07 nm / sec and 0.1 nm / sec, respectively. A first electron transport layer having a thickness of 70 nm was provided by evaporation.

  After returning the substrate temperature to room temperature, the heating boat containing ET-14 is energized and heated, and deposited on the first electron transport layer at a deposition rate of 0.1 nm / sec. The electron transport layer was provided.

  In the same manner as described above, a substrate prepared separately was provided up to the second electron transport layer. When X-ray diffraction measurement was performed at three points near the center of the substrate, the crystallinity was calculated, and the average of the three points was 18%. An X-ray diffraction peak due to crystal grains was detected in the electron transport layer. It was. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

  Then, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 601 was produced.

  About the obtained organic EL element 501, it sealed similarly to the organic EL element 101, and formed the illuminating device as shown in FIG. 6, FIG.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 7
[Production of Organic EL Element 701]
In the production of the organic EL element 601, a light emitting layer was produced in the same manner except that Compound Example Host-39 was used instead of Compound Example 17.

  Subsequently, the coating liquid 1 for electron carrying layers was prepared as follows, and it apply | coated on the conditions of 700 rpm and 30 seconds with the spin coater. The film thickness was 55 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

  A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. When the X-ray diffraction measurement was performed at three points near the center of the substrate, the crystallinity was calculated and the average of the three points was 0.1% or less, and the X-ray diffraction peak due to the crystal grains in the electron transport layer Was not detected. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

(Coating liquid 1 for electron transport layer)
2,2,3,3-tetrafluoro-1-propanol 100 g
Compound 91 (HPLC purity 97.8%) 0.9 g
Next, the substrate provided up to the electron transport layer was moved to a vapor deposition machine without being exposed to the atmosphere, and the pressure was reduced to 4 × 10 ⁻⁴ Pa. Note that potassium fluoride and aluminum were each placed in a tantalum resistance heating boat and attached to a vapor deposition machine.

  First, a resistance heating boat containing potassium fluoride was energized and heated to provide 1 nm of an electron injection layer made of potassium fluoride on the substrate. Subsequently, a resistance heating boat containing aluminum was energized and heated, and a cathode having a film thickness of 100 nm made of aluminum was provided within a deposition rate range of 1 to 2 nm / second, whereby an organic EL element 701 was produced.

[Production of Organic EL Element 702]
In the organic EL element 701, an organic EL element 702 was formed in the same manner as the organic EL element 701 except that the following electron transport layer coating liquid 2 was used instead of the electron transport layer coating liquid 1.

(Coating liquid 2 for electron transport layer)
2,2,3,3-tetrafluoro-1-propanol 100 g
Compound 91 (HPLC purity 99.8%) 0.9 g
A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. X-ray diffraction measurement was performed at three points near the center of the substrate, and the degree of crystallinity was calculated. The average of the three points was 5%, and an X-ray diffraction peak due to crystal grains was detected in the electron transport layer. It was done. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line).

[Evaluation of organic EL elements 701 and 702]
When the obtained organic EL elements 701 and 702 were evaluated, they were sealed in the same manner as the organic EL element 101 of Example 1, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

  Next, as in Example 1, external extraction quantum efficiency, drive voltage, and light emission lifetime were evaluated.

表４より、ＨＰＬＣ純度の高い材料を用いた素子では電子輸送層中に結晶粒が観察され、外部取り出し量子効率が高く、駆動電圧が低く、且つ、発光寿命も長いことが明らかである。

From Table 4, it is clear that in the device using a material having high HPLC purity, crystal grains are observed in the electron transport layer, the external extraction quantum efficiency is high, the driving voltage is low, and the light emission lifetime is long.

Example 8
[Production of White Organic EL Element 801]
In the production of the organic EL element 401, a light emitting layer was formed using the compound 104 instead of the HOST-54, D-10 instead of the D-6, and D-52 instead of the D-48. An organic EL device 801 was produced in the same manner except that the compound 103 was used to form an electron transport layer. The thickness of the electron transport layer was 60 nm.

  A substrate prepared separately was provided up to the electron transport layer in the same manner as described above. When X-ray diffraction measurement was performed on three points near the center of the substrate, X-ray diffraction lines were observed, and the presence of crystal grains was confirmed. The X-ray diffraction measurement was performed according to the method described in the above section (X-ray diffraction line). Moreover, particles were observed with an electron microscope, and the presence of crystal grains was confirmed. About the obtained organic EL element 801, it sealed similarly to the organic EL element 101 of Example 1, and formed the illuminating device as shown to FIG. 6, FIG.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

  Since the organic EL element of the present invention can be driven at a low voltage and has a long lifetime, it can be applied to low power consumption of an image display device, a lighting device, and the like.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part L Light 21 X-ray-diffraction line (without crystal grains)
22 X-ray diffraction lines (with crystal grains)
23 X-ray diffraction lines (with crystal grains)
24 X-ray diffraction lines (crystal powder)
DESCRIPTION OF SYMBOLS 101 Organic EL element 102 Glass cover 104 Electron transport layer 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (10)

An organic electroluminescence device having at least an anode, a light emitting layer containing at least one phosphorescent dopant, and at least one electron transport layer,
The electron transport layer contains at least one electron transport material;
The film thickness of the electron transport layer is in the range of 50 to 200 nm,
An organic electroluminescence device, wherein the electron transport layer includes crystal grains of the electron transport material, and X-ray diffraction lines due to the crystal grains are observed.   The organic electroluminescence device according to claim 1, wherein the electron transport layer is made of a single material. The organic electroluminescence device according to claim 1, wherein the electron transport material is represented by the following general formula (1).

(In the formula, Ar ₁ represents an aromatic condensed ring which may have a substituent, Ar ₂ and Ar ₃ represent an aromatic ring which may have a substituent, and A ₁ , Ar ₂ , Ar ₃ , n01, n02 and n03 satisfy the following formula (1): n01 represents an integer of 1 or more, n02 and n03 represent an integer of 0 to 3, and n01 + n02 + n03 ≧ 2. When Ar is 2 or more, Ar ₁ , Ar ₂ and Ar ₃ may be the same or different.)
Formula (1)
{(Number of rings constituting the aromatic condensed ring represented by Ar ₁ ) × n01} + {(Number of rings constituting the aromatic condensed ring represented by Ar ₂ ) × n02} + {(Ar ₃ The number of rings constituting the aromatic condensed ring represented by: xn03} ≧ 4 The compound of general formula (1) is a compound represented by general formula (b), The organic electroluminescent element of any one of Claims 1-3 characterized by the above-mentioned.

(In the formula, X ₂₀ represents O or S, X _{21 to} X ₂₈ represent C (R ₂₀ ) or N, R ₂₀ represents a hydrogen atom or a substituent. At least one of R ₂₀ is represented by the following general formula: (Represented by the formula (b1))

(In the formula, L ₂₀ represents a divalent linking group derived from an aromatic hydrocarbon ring or an aromatic heterocyclic ring. N23 represents 0 or an integer of 1 to 3, and when n23 is 2 or more, a plurality of L ₂₀ May be the same or different. * Represents a site of connection with the mother nucleus of the general formula (b), Ar ₂₀ represents a group represented by the following general formula (b2).

(In the formula, X ₂₉ represents N (R ₂₁ ), O or S, E _{21 to} E ₂₈ represent C (R ₂₂ ) or N, and R ₂₁ and R ₂₂ represent a hydrogen atom, a substituent, or L ₂₀ . of represents a linking site. * represents a linking site with L _20.)   The organic electroluminescence device according to claim 1, wherein the electron transport layer is formed by a wet process. The organic phosphorescent device according to claim 1, wherein the phosphorescent dopant is represented by the following general formula (a).

(In the formula, R ₁ represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring together with C—B _0. N ₁ represents an integer of 0 to 5. B ₀ Represents a carbon atom or a nitrogen atom, and B _{1 to} B ₅ are C (R ₁₁ ), N, N (R ₁₁ ), S, C (R ₁₁ ) = C (R ₁₂ ), C (R ₁₁ ) = N Or N = N, and the ring formed by B _{1 to} B ₅ together has at least one nitrogen atom and represents a monocyclic aromatic nitrogen-containing heterocyclic ring, and R ₁₁ and R ₁₂ are hydrogen atoms or substituted M ₁ represents a group 8 to 10 metal in the periodic table, X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents a bidentate arrangement with X ₁ and X _2. Represents an atomic group forming a ligand, m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 is 2 or 3.   The organic electroluminescence device according to claim 1, wherein the organic electroluminescence device has a layer formed by at least two wet processes.   The organic electroluminescent element according to any one of 1 to 7, which emits white light.   The illuminating device provided with the organic electroluminescent element of any one of Claims 1-7.   A display device comprising the organic electroluminescence element according to claim 1.

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