JP2012124359A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white phosphorescent organic EL element having excellent performance stability for variation in dopant concentration in an organic electroluminescent element which ensures low voltage drive by improving injection into a phosphorescent layer, and exhibits white light emission by containing a plurality of phosphorescent dopants having different emission wavelength, and to provide a luminaire.SOLUTION: In an organic EL element having a pair of electrodes and a luminous layer arranged between the electrodes, the luminous layer contains at least one kind of phosphorescent dopant having the λmax of emission in the range of 300-480 nm. The dopant has a partial structure of metal complex, the luminous layer contains at least a host compound and the phosphorescent dopant. Concentration of the phosphorescent dopant in the luminous layer is not constant in the thickness direction, and the thickness of the luminous layer is 70 nm or more.

Description

  The present invention relates to an organic EL device in which a concentration gradient is applied to a light emitting layer to make the light emitting layer thick.

  The organic EL device of the present invention has a very high performance uniformity for a large area panel. In particular, an element having very good color stability in a white element can be easily obtained.

  As a light-emitting electronic display device, there is an electroluminescence display (hereinafter abbreviated as ELD). As a constituent element 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, an organic electroluminescence device has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and excitons (exciton) are injected by injecting electrons and holes into the light emitting layer and recombining them. ), Which emits light by using light emission (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several V to several tens of V, and further self-emission. Since it is a type, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoints of space saving, portability, and the like.

  Another major feature of the organic electroluminescence element is that it is a surface light source, unlike main light sources that have been put to practical use, 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.

Furthermore, in recent years, a phosphorescent type with high quantum efficiency has been desired as an organic EL element for illumination use from the viewpoint of low power consumption due to an increase in environmental awareness. However at present, blue for a phosphorescent there is a problem of equal is very T ₁ is greater high-voltage, short life.

  On the other hand, when an organic electroluminescence element is used as such a light source for illumination or a backlight of a display, it is used as a light source that exhibits white or a so-called light bulb color (hereinafter collectively referred to as white). In order to obtain white light emission with an organic electroluminescence element, a method of adjusting a plurality of light emitting dopants having different emission wavelengths in one element and obtaining white color by mixing, a multicolor light emitting pixel, for example, blue, green, red There are a method in which three colors are applied simultaneously and light is emitted and mixed to obtain white, and a method in which white is obtained by using a color conversion dye (for example, a combination of a blue light emitting material and a color conversion fluorescent dye).

  However, judging from various requirements for light sources for illumination and backlights, such as low cost, high productivity, and simple driving methods, a plurality of light emitting dopants having different emission wavelengths are adjusted in one element, and color mixing is performed. A method of obtaining a white color is effective for these applications, and research and development have been actively promoted in recent years.

  The method for obtaining white light by the above-described method will be described in more detail. A method for obtaining white by mixing two-color light emitting dopants having complementary colors in the device, for example, a blue light emitting dopant and a yellow light emitting dopant, and blue -A method of obtaining a white color by mixing three colors of light emitting dopants of green and red and mixing them.

  For example, a method for obtaining a white organic electroluminescent element by doping high-efficiency phosphors of blue, green, and red as a light emitting material is disclosed (for example, see Patent Documents 1 and 2). .

  In addition, in an organic electroluminescence device that emits white light, the layers having different emission colors are not separated from each other, but two or more colors of luminescent dopants are allowed to coexist in one layer, and relative to the luminescent dopant having high emission energy. There is a method of emitting multiple colors by energy transfer to a light emitting dopant with low efficiency. This method is one of the effective methods for obtaining a white light-emitting organic EL device because the number of organic layers can be reduced and the amount of light-emitting dopant used can be reduced. For example, Patent Document 3 discloses an organic electroluminescent device in which a red light emitting layer and a blue light emitting layer are sequentially provided from an anode, and the red light emitting layer contains at least one green light emitting dopant. ing.

  By the way, in recent years, a phosphorescent dopant capable of obtaining a higher-luminance organic electroluminescence device has been actively developed for fluorescent materials (see, for example, Patent Document 4 and Non-Patent Documents 1 and 2). The light emission from the conventional fluorescent material is light emission from the excited singlet, and the generation ratio of the singlet exciton and the triplet exciton is 1: 3. Therefore, the generation probability of the luminescent excited species is 25%. On the other hand, in the case of a phosphorescent dopant using light emission from an excited triplet, the upper limit of the internal quantum efficiency is 100% due to the exciton generation ratio and the internal conversion from a singlet exciton to a triplet exciton. Therefore, in principle, the luminous efficiency is up to four times that in the case of the fluorescent luminescent dopant.

  However, by using a phosphorescent dopant, two or more colors of luminescent dopants can coexist in one layer, and a multicolor light is emitted by energy transfer from a luminescent dopant having a high luminescence energy to a dopant having a relatively low efficiency. When trying to obtain an organic electroluminescence device, it is relatively easy to ensure driving conditions of chromaticity and stability to the environment as compared with the case of obtaining a white color by laminating a plurality of layers having different emission colors. It has been found that the stability of chromaticity with respect to driving conditions, device driving aging or storage aging is not necessarily at a sufficient level. In particular, in the light source application for illumination, the demand for the stability of the emission color is severe, and how to ensure the stability of chromaticity is an important issue in order to put the organic electroluminescence element into practical use for the illumination light source. ing.

  For example, Patent Document 5 discloses a technique for facilitating charge transfer by changing the concentration of the light emitting material in the light emitting layer, thereby reducing voltage and increasing light emission efficiency. Patent Document 6 also discloses a similar technique. However, a configuration example of a white element using a phosphorescent material that emits blue light is not disclosed, and there is no description regarding chromaticity stability. In Patent Document 7, there is a description of the concentration gradient of the blue phosphorescent dopant, but there is no description about the white element and the chromaticity stability in the white element, and there is no description about the relationship with the HOMO level of the phosphorescent material. .

JP-A-6-207170 JP 2004-235168 A International Publication No. 2004/077786 Pamphlet US Pat. No. 6,097,147 Japanese Patent No. 3778623 Japanese Patent No. 4181895 Special table 2010-515255

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000)

  The present invention has been made in view of the above-mentioned problems. One of the objects is to improve the injection into the phosphorescent light emitting layer and realize low voltage driving, and the other is a plurality of phosphorescent light having different emission wavelengths. An organic electroluminescence device that has a light emitting dopant and emits white light, and provides a white phosphorescent organic electroluminescence device excellent in performance stability against a change in dopant concentration, and an illumination device using the same.

  The above object of the present invention is achieved by the following configurations.

1. In an organic electroluminescence device having a pair of electrodes consisting of at least an anode and a cathode and a light emitting layer disposed between the electrodes,
The light emitting layer contains (A) at least one phosphorescent dopant having a light emission λmax of 300 to 480 nm,
(B) The dopant has at least one partial structure selected from the following general formulas (A) to (D),
(C) The light emitting layer contains at least a host compound and the phosphorescent light emitting dopant, and the concentration of the phosphorescent light emitting dopant in the light emitting layer is not constant in the film thickness direction,
(D) The organic electroluminescent element characterized by the film thickness of this light emitting layer being 70 nm or more.

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]

[Wherein, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb, Rc, Rb1, and Rc1 each represents a hydrogen atom or a substituent, and A1 represents an aromatic ring or an aromatic heterocyclic ring. Represents the residues necessary to form and M represents Ir or Pt. ]

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]
2. 2. The organic electroluminescence device according to 1 above, wherein the concentration of the phosphorescent dopant in the light emitting layer is high at the anode side interface.

  3. 3. The organic electroluminescence according to 1 or 2 above, wherein an average concentration of the phosphorescent dopant is 5 to 30% by mass in a portion excluding a 20 nm portion in thickness from the anode side interface of the light emitting layer. element.

  4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein the phosphorescent dopant has a highest electron occupation level shallower than 5.3 eV.

  5). 5. The organic electroluminescence device according to any one of 1 to 4, wherein the highest electron occupation level of the host compound of the light emitting layer is 0.2 eV or more deeper than the phosphorescent light emitting dopant.

  6). 6. The organic electro of any one of 1 to 5 above, wherein the emission color is 0.1 or less in y value deviation from the black body radiation at each color temperature defined in the CIE 1931 color system. Luminescence element.

  7). 7. The organic electroluminescence device according to any one of 1 to 6, wherein at least one of the electrodes is a transparent electrode containing silver nanoparticles or silver nanowires.

  8). 8. The organic electroluminescence device according to any one of 1 to 7, wherein at least one of the electrodes is a transparent electrode containing carbon nanotubes having an outer diameter of less than 3.5 nm.

  INDUSTRIAL APPLICABILITY According to the present invention, a white phosphorescent organic electroluminescent device that improves injection into a phosphorescent light emitting layer, can realize low voltage driving, and exhibits excellent performance stability against a change in dopant concentration in an organic electroluminescent device that emits white light. And a lighting device using the same.

It is the schematic which shows an example of the illuminating device incorporating the organic EL element of this invention. It is sectional drawing which shows an example of the illuminating device incorporating the organic EL element of this invention.

  Hereinafter, the details of each component of the white phosphorescent organic electroluminescence device of the present invention (hereinafter also referred to as the organic EL device of the present invention) will be sequentially described.

<< White chromaticity of organic electroluminescence element >>
The preferred chromaticity as a white element in the present invention is a correlated color temperature of 2500 K to 7000 K, and in the CIE 1931 color system, the y value deviation is 0.1 or less from the black body radiation at each color temperature.

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

<< Layer structure of organic EL element >>
Next, although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.

(I) Anode / light emitting layer unit / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer unit / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer unit / hole blocking Layer / electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emission Layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode In the organic EL device of the present invention, the light emitting layer unit has at least one light emitting layer having a configuration satisfying the requirements defined in the present invention. Any number of layers may be used as long as it is present, but it is preferably composed of only one light emitting layer having a requirement satisfying the provisions of the present invention.

<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 structure of the light emitting layer according to the present invention is not particularly limited as long as it satisfies the requirements defined in the present invention.

  The total thickness of the light emitting layer is characterized by being thicker than before. The light emitting layer of the present invention increases the injection characteristics by the highest electron occupation level design of a light emitting dopant described later and a bold dopant concentration gradient structure, and ensures low voltage driving by designing the carrier mobility well, It is possible to realize a thicker light emitting layer design than before, and is characterized by both high performance and high stability. The thickness of the light emitting layer of the present invention is at least 70 nm or more, preferably 80 nm or more, more preferably 100 nm or more and less than 500 nm.

  As a method for forming the light emitting layer, a light emitting dopant or a host compound described later can be used, for example, a vacuum deposition method, a spin coating method, a casting method, an LB method (Langmuir-Blodget method), an ink jet method, a spray method, a printing method, The film can be formed by a known thin film forming method such as a slot type coater method.

  In the present invention, the light emitting layer contains at least one phosphorescent dopant having an emission λmax of 300 nm to 480 nm, and the dopant is at least one portion selected from the general formulas (A) to (D). And the light-emitting layer contains at least a host compound and the phosphorescent light-emitting dopant, and the concentration of the phosphorescent light-emitting dopant in the light-emitting layer is not constant. It is contained at a high concentration on the anode side of the layer, and is contained with a concentration distribution so as to become a low concentration toward the center or the cathode side.

  In the organic EL device of the present invention, the light emitting layer may have two or more layers, but preferably comprises only one light emitting layer described above.

  In the white element of the present invention, the light emitting layer has a plurality of phosphorescent light emitting dopants, but at least a phosphorescent light emitting dopant (phosphorescent light emitting dopant A) having a light emission λmax in a wavelength region of 300 nm to 480 nm and a light emission λmax are present. It has a phosphorescent dopant (phosphorescent dopant B) in a wavelength region of 580 nm or more.

  The light emitting layer containing the phosphorescent dopants A and B preferably further includes at least one kind of phosphorescent dopant C having a maximum emission intensity in a wavelength region of 500 nm or more and less than 580 nm in order to improve color rendering. In the light emitting layer, the phosphorescent dopant A and the phosphorescent dopants B to C have a molar concentration ratio in which the phosphorescent dopant A is 10 times or more of the phosphorescent dopant B or C in order to obtain suitable white light emission. preferable.

  Next, the concentration distribution of the phosphorescent dopant A having the emission λmax of 300 nm to 480 nm in the light emitting layer will be described.

  In the present invention, the phosphorescent dopant A is preferably contained at a high concentration on the anode side of the light emitting layer, and has a concentration distribution so that the concentration decreases from the center toward the cathode side. The average content of the phosphorescent light emitting dopant A in the portion from the anode side end of the light emitting layer to the central portion of the light emitting layer may be larger than the average content from the cathode side end to the central portion of the light emitting layer. It is a preferable aspect that the end portion has the highest concentration and monotonously decreases from the anode side end portion to the cathode side end portion. Monotonically decreasing means that there is no region where the concentration of the light-emitting dopant A increases from the anode side toward the cathode, and it may be reduced constantly, the reduction coefficient may vary, It may be constant or both are good modes.

  In the present invention, the region that affects carrier injection is considered to be a region within 20 nm from the anode and cathode interface of the light emitting layer, but more strictly, it is important to increase and control the concentration of each 10 nm region.

  The content of the phosphorescent dopant A at the anode side end in the light emitting layer is preferably 35% by mass or more and less than 100% by mass. More preferably, it is 40 mass% or more and less than 90 mass%, Most preferably, it is 50 mass% or more and less than 80 mass%. If it is less than 35% by mass, the power efficiency is lowered, and the chromaticity stability during driving tends to be poor. When the content is 100% by mass, the film quality is slightly poor and the adhesiveness and device storage time tend to be slightly inferior.

  On the other hand, the phosphorescent dopant concentration of the light emitting layer excluding the 20 nm portion from the end is preferably 5 to 30% by mass, more preferably 10 to 25% by mass. By bringing the emission center in this region, very good performance can be obtained.

  With the light emitting layer having the structure of the present invention, a white phosphorescent organic electroluminescence device having excellent power efficiency and excellent stability in chromaticity versus driving voltage, versus driving time and device storage can be obtained. The mechanism of action that brings about the effects of the present invention is not necessarily elucidated and is not speculative. However, phosphorescent layers, particularly phosphorescent layers that emit blue light, have a large energy gap, and electrons or holes. It is expected that there will be a large barrier to the injection of such charges into the light emitting layer. The structure of the present invention is expected to improve the injection of this charge into the light-emitting layer, but the effect of the present invention is not obtained in any combination with any material, and the phosphorescence of the present invention is not particularly effective. It has been found that a remarkable effect can be obtained in combination with the light emitting dopant A and further with the host compound.

  For example, Japanese Patent No. 3778623 discloses a technique for facilitating charge transfer by changing the concentration of the light emitting material in the light emitting layer to lower the voltage and increase the light emission efficiency. However, a configuration example of a white element using a phosphorescent material that emits blue light is not disclosed, and in particular, the effect of the present invention relating to chromaticity stability cannot be predicted. Furthermore, the remarkable effect in the combination with the phosphorescent material of the present invention cannot be foreseen. In JP 2010-515255 A, there is a description of the concentration gradient of the blue phosphorescent dopant, but there is no description of the white element and the chromaticity stability in the white element, and the HOMO level of the phosphorescent material in the present invention is It is not possible to foresee a great effect on the relationship.

<Dopant distribution measurement method description>
There are several methods for measuring the distribution of the dopant in the depth direction, but dynamic secondary ion mass spectrometry is preferred when there are specific elements. D-SIMS can analyze the amount of elements in the film with high sensitivity and can follow the concentration change of elements in the depth direction. As for secondary ion mass spectrometry, for example, Japanese Society for Surface Science “Secondary ion mass spectrometry (Surface Science and Technology Selection)” (Maruzen) can be referred to.

In dynamic secondary ion mass spectrometry, a sample surface is irradiated with an ion beam called primary ions under a high vacuum of about 10 ⁻⁸ Pa to perform sputtering. This is a method of analyzing elements present on the surface by mass spectrometry of secondary ions in the constituent particles released thereby. Although the surface is sputtered and scraped off, it is possible to analyze the change in element concentration from the surface to a depth of μm or more, although it is a destructive analysis.

As the primary ions, for example, metal ion species such as Cs ⁺ and O ₂ ⁺ are preferable, but which ion species is preferably used depends on the element to be measured.

When it is desired to measure the compound itself, the time-of-flight secondary ion mass spectrometry (ToF-SIMS) method is preferred. In this case, it is possible to know the distribution of the dopant compound in the depth direction by measuring the distribution of fragment ions obtained from the compound with respect to the oblique cross-sectional portion that is scraped off and the organic layer is cut off. Examples of the oblique cutting method include a method using an ultramicrotome used for preparing a sample for an electron microscope, and a method using a precision oblique cutting device such as a die-plautes Cycus NN type. Regarding the ToF-SIMS method, for example, the Japan Surface Science Society “Secondary Ion Mass Spectrometry (Surface Science and Technology Selection)” (Maruzen) can be referred to. In the ToF-SIMS method, sputtering is performed by irradiating a sample surface with an ion beam called primary ions under a high vacuum of about 10 ⁻⁸ Pa. It is a method of analyzing compounds present on the surface by mass spectrometry of secondary ions emitted by very gentle sputtering by making the primary ion beam very low current and pulsed. . By measuring while scanning the primary ions, the distribution of secondary ions emitted by sputtering can be measured. As the primary ions, for example, Ga ⁺ , In ⁺ , Bi ⁺ , Au ⁺ metal ion species and their cluster ions are preferable, and which ion species is preferably used depends on the element to be measured.

  For example, when forming by vapor deposition, the concentration gradient of the luminescent dopant is formed by changing the vapor deposition ratio with other co-deposition components, but after formation, the depth is obtained by sputtering in the depth direction by the above method. The distribution of directions can be measured.

[Host compound]
Next, a host compound and a light emitting dopant (also referred to as a light emitting host compound and a light emitting dopant compound) included in the light emitting layer will be described.

  The host compound contained in the light emitting layer of the organic EL device of the present invention is preferably a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1, more preferably phosphorescence quantum yield. A compound with a rate of less than 0.01. Moreover, in the compound contained in a light emitting layer, it is preferable that the mass ratio in the layer is 20 mass% or more.

  As a host compound, a host compound may be used independently or may be used in combination of multiple types.

  The light-emitting host compound used in the present invention is not particularly limited in terms of structure, but typically, a carbazole derivative, a triarylamine derivative, an aromatic borane derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, Those having a basic skeleton such as an oligoarylene compound, or a carboline derivative or a diazacarbazole derivative (herein, a diazacarbazole derivative means that at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is nitrogen Represents an atom substituted with an atom.) And the like.

  As the light emitting host compound used in the light emitting layer according to the present invention, the compound represented by the general formula (a) is preferable.

  In the formula, X represents NR ′, O, S, CR′R ″ or SiR′R ″. R ′ and R ″ each represent a hydrogen atom or a substituent. Ar represents an aromatic ring. N represents an integer of 0 to 8.

  In X in the general formula (a), the substituents represented by R ′ and R ″ are alkyl groups (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group). Group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl group, allyl group, 1-propenyl group, 2 -Butenyl group, 1,3-butadienyl group, 2-pentenyl group, isopropenyl group, etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon group (aromatic carbocyclic group, aryl group, etc.) For example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, an Ryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc., aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group) Group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom) ), A phthalazinyl group, etc.), a heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), an alkoxy group (eg, methoxy group, ethoxy group, propyloxy group, pentyloxy group, Hexyloxy group, oct Ruoxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy 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.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (Eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, etc.) Xycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, Dodecylaminosulfonyl 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 (For example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethyl group) Carbonylamino group, propylcarbonylamino 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, A cyclohexylaminocarbonyl group, an octylaminocarbonyl group, a 2-ethylhexylaminocarbonyl group, a dodecylaminocarbonyl group, a phenylaminocarbonyl group, a naphthylaminocarbonyl group, a 2-pyridylaminocarbonyl group, etc.), a ureido group (for example, a methylureido group, Ethylureido group, pentylureido 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, Dilsulfinyl group etc.), alkylsulfonyl group (eg methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group etc.), arylsulfonyl group or heteroarylsulfonyl group (eg , Phenylsulfonyl group, naphthylsulfonyl 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, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, Tafluoroethyl 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 Groups and the like.

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  In the general formula (a), X is preferably NR ′ or O, and R ′ is particularly preferably an aromatic hydrocarbon group or an aromatic heterocyclic group.

  In the general formula (a), examples of the aromatic ring represented by Ar include an aromatic hydrocarbon ring and an aromatic heterocyclic ring. Further, the aromatic ring may be a single ring or a condensed ring, and may be unsubstituted or may have a substituent as described later.

  In the general formula (a), examples of the aromatic hydrocarbon ring represented by Ar include a 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, Examples include a pyranthrene ring and anthraanthrene ring. These rings may further have a substituent.

  In the general formula (a), examples of the aromatic heterocycle represented by Ar include a furan ring, a dibenzofuran ring, a thiophene ring, an oxazole ring, a pyrrole ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring. , Benzimidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indazole ring, indazole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, cinnoline ring, quinoline Ring, isoquinoline ring, phthalazine ring, naphthyridine ring, carbazole ring, carboline ring, diazacarbazole ring (showing a ring in which one of the carbon atoms of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom), etc. Can be mentioned. These rings may further have a substituent.

  Among these, in the general formula (a), the aromatic ring represented by Ar is preferably a carbazole ring, a carboline ring, a dibenzofuran ring, or a benzene ring, and particularly preferably used is a carbazole ring, A carboline ring or a benzene ring. Among these, a benzene ring having a substituent is preferable, and a benzene ring having a carbazolyl group is particularly preferable.

  In the general formula (a), the aromatic ring represented by Ar is preferably a condensed ring having three or more rings, as shown below, and is an aromatic hydrocarbon in which three or more rings are condensed. Specific examples of the condensed ring include naphthacene ring, anthracene ring, tetracene ring, pentacene ring, hexacene ring, phenanthrene ring, pyrene ring, benzopyrene ring, benzoazulene ring, chrysene ring, benzochrysene ring, acenaphthene ring, acenaphthylene ring, Triphenylene ring, coronene ring, benzocoronene ring, hexabenzocoronene ring, fluorene ring, benzofluorene ring, fluoranthene ring, perylene ring, naphthoperylene ring, pentabenzoperylene ring, benzoperylene ring, pentaphen ring, picene ring, pyranthrene ring, coronene ring , Naphthocoronene ring, Ovalene ring, Anse Antoren ring and the like. In addition, these rings may further have a substituent.

  Specific examples of the aromatic heterocycle condensed with three or more rings include an acridine ring, a benzoquinoline ring, a carbazole ring, a carboline ring, a phenazine ring, a phenanthridine ring, a phenanthroline ring, a carboline ring, a cyclazine ring, Kindin ring, tepenidine ring, quinindrin ring, triphenodithiazine ring, triphenodioxazine ring, phenanthrazine ring, anthrazine ring, perimidine ring, diazacarbazole ring (any one of the carbon atoms constituting the carboline ring is a nitrogen atom Phenanthroline ring, dibenzofuran ring, dibenzothiophene ring, naphthofuran ring, naphthothiophene ring, benzodifuran ring, benzodithiophene ring, naphthodifuran ring, naphthodithiophene ring, anthrafuran ring, anthradifuran ring, A Tiger thiophene ring, anthradithiophene ring, thianthrene ring, phenoxathiin ring, such as thio fan Tren ring (naphthaldehyde thiophene ring), and the like. In addition, these rings may further have a substituent.

  Here, in the general formula (a), the substituents that the aromatic ring represented by Ar may have are the same as the substituents represented by R ′ and R ″.

  In the general formula (a), n represents an integer of 0 to 8, preferably 0 to 2, and particularly preferably 1 or 2 when X is O or S.

  Specific examples of the light-emitting host compound represented by the general formula (a) are shown below, but are not limited thereto.

  The host compound 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 (evaporation polymerizable light emitting host). .

  As the host compound, a compound having a hole transporting ability and an electron transporting ability, which prevents emission of longer wavelengths and has a high Tg (glass transition temperature) is preferable.

  As specific examples of conventionally known host compounds, compounds described in the following documents are suitable. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  In the present invention, in the case of having a plurality of light emitting layers, the host compound may be different for each light emitting layer, but the same compound is preferable because excellent driving life characteristics are obtained.

  In addition, the host compound preferably has a lowest excited triplet energy (T1) larger than 2.7 eV because higher luminous efficiency can be obtained. The lowest excited triplet energy as used in the present invention refers to the peak energy of an emission band corresponding to the transition between the lowest vibrational bands of a phosphorescence emission spectrum observed at a liquid nitrogen temperature after dissolving a host compound in a solvent.

  In the present invention, a compound having a glass transition point of 90 ° C. or higher is preferable, and a compound having a glass transition temperature of 130 ° C. or higher is preferable because excellent driving life characteristics can be obtained.

  Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  In the organic EL device of the present invention, since the host material is responsible for carrier transport, a material having carrier transport capability is preferable. Carrier mobility is used as a physical property representing carrier transport ability, but the carrier mobility of an organic material generally depends on the electric field strength. Since a material having a high electric field strength dependency easily breaks the balance of hole and electron injection / transport, it is preferable to use a material having a low electric field strength dependency of mobility for the intermediate layer material and the host material.

  The highest electron occupation level of the host compound in the light emitting layer of the present invention is preferably 0.2 eV or more deeper than the phosphorescent dopant described later, more preferably 0.4 eV or more deeper. This potential difference makes it possible to achieve both injection and light emission efficiently.

[Luminescent dopant]
Next, the light emitting dopant according to the present invention will be described.

  As the light-emitting dopant according to the present invention, a phosphorescent dopant (hereinafter also referred to as a phosphorescent emitter, a phosphorescent compound, or a phosphorescent compound) is used.

  The present invention contains at least one phosphorescent dopant having an emission λmax of 300 to 480 nm, and the dopant has at least one partial structure selected from the following general formulas (A) to (D).

(Partial structures represented by general formulas (A) to (D))
In the present invention, the phosphorescent dopant A has at least one partial structure selected from the general formulas (A) to (D).

  In the general formula (A), Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represents a hydrogen atom or a substituent, and A1 represents an aromatic ring or an aromatic heterocyclic ring. Represents the residues necessary to form and M represents Ir or Pt.

In the general formula (B), Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb, Rc, Rb ₁ and Rc ₁ each represent a hydrogen atom or a substituent, and A1 represents It represents a residue necessary for forming an aromatic ring or an aromatic heterocyclic ring, and M represents Ir or Pt.

  In the general formula (C), Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represents a hydrogen atom or a substituent, and A1 represents an aromatic ring or an aromatic group. It represents a residue necessary for forming a heterocyclic ring, and M represents Ir or Pt.

  In the general formula (D), Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represents a hydrogen atom or a substituent, and A1 represents an aromatic ring or an aromatic group. It represents a residue necessary for forming a heterocyclic ring, and M represents Ir or Pt.

  In the general formulas (A) to (D), Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, and the aliphatic group represented by Ra includes an alkyl group (for example, a methyl group, an ethyl group, Group, propyl group, butyl group, pentyl group, isopentyl group, 2-ethyl-hexyl group, octyl group, undecyl group, dodecyl group, tetradecyl group), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group), and the like. As the aromatic group, for example, phenyl group, tolyl group, azulenyl group, anthranyl group, phenanthryl group, pyrenyl group, chrysenyl group, naphthacenyl group, o-terphenyl group, m-terphenyl group, p-terphenyl group, Examples include acenaphthenyl group, coronenyl group, fluorenyl group, perylenyl group, etc. It may have. As the heterocyclic group, for example, pyrrolyl group, indolyl group, furyl group, thienyl group, imidazolyl group, pyrazolyl group, indolizinyl group, quinolinyl group, carbazolyl group, indolinyl group, thiazolyl group, pyridyl group, pyridazinyl group, thiadiazinyl group, An oxadiazolyl group, a benzoquinolinyl group, a thiadiazolyl group, a pyrrolothiazolyl group, a pyrrolopyridazinyl group, a tetrazolyl group, an oxazolyl group, a chromanyl group, and the like can be mentioned, and these groups each may have a substituent.

In the general formulas (A) to (D), examples of the substituent represented by Rb, Rc, Rb ₁ and Rc ₁ 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). Group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group etc.), cycloalkyl group (eg cyclopentyl group, cyclohexyl group etc.), alkenyl group (eg vinyl group, allyl group etc.), alkynyl Group (eg, ethynyl group, propargyl group, etc.), aryl group (eg, phenyl group, naphthyl group, etc.), aromatic heterocyclic group (eg, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group) , Triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, phthala Nyl group, etc.), heterocyclic group (eg pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group etc.), alkoxyl group (eg methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group) Group, dodecyloxy group, etc.), cycloalkoxyl group (eg, cyclopentyloxy group, cyclohexyloxy 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.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alcohol Sicarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.) ), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl 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 (eg, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group) Group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenyl Carbonylamino 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, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group) Octylureido group, dodecylureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, Tylsulfinyl 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 (phenylsulfonyl group, naphthylsulfonyl 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, Phthalylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluoro) Phenyl group, etc.), cyano group, nitro group, hydroxyl group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents.

  In the general formulas (A) to (D), A1 represents a residue necessary for forming an aromatic ring or an aromatic heterocyclic ring, and the aromatic ring includes a benzene ring, a biphenyl ring, a naphthalene ring, and an 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, anthraanthrene ring, etc., and the aromatic heterocycle includes furan ring, thiophene ring, pyridine ring, pyridazine ring , Pyrimidine ring, pyrazine ring, 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, carboline ring, diazacarbazole ring (carbonization constituting carboline ring) A ring in which one of the carbon atoms of the hydrogen ring is further substituted with a nitrogen atom).

  The structures of the general formulas (A) to (D) are partial structures, and a ligand corresponding to the valence of the central metal is necessary for the structure itself to be a light-emitting dopant of a completed structure. Specifically, halogen (for example, fluorine atom, chlorine atom, bromine atom or iodine atom), aryl group (for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, biphenyl group, naphthyl group) , Anthryl group, phenanthryl group, etc.), alkyl group (for example, methyl group, ethyl group, isopropyl group, hydroxyethyl group, methoxymethyl group, trifluoromethyl group, t-butyl group, etc.), alkyloxy group, aryloxy group , Alkylthio group, arylthio group, aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group, quinazolinyl group, carbazolyl group , Carbolinyl group, phthalazinyl group, etc.), one Formula (A) ~ partial structure such as metal except for the (D) can be mentioned.

  In the general formulas (A) to (D), M represents Ir or Pt, and Ir is particularly preferable. Moreover, the tris body which becomes a complete structure with three partial structures of general formula (A)-(D) is preferable.

  Hereinafter, although the compound which has the partial structure of the said general formula (A)-(D) of the light emission dopant which concerns on this invention is illustrated, it is not limited to these.

In the formulas D-100 to D-143, M represents Ir or Pt, and Y ² and Y ³ represent hydrogen, methyl, ethyl, n-propyl, isopropyl or t-butyl. Y ³ preferably means methyl, ethyl, n-propyl, isopropyl or t-butyl. Also included are isomer compounds of the formulas D-100 to D-143.

  Furthermore, in the present invention, the ionization potential energy of the luminescent dopant is preferably smaller than 5.3 eV in order to improve the efficiency and the chromaticity stability. That is, it is preferable that the highest electron occupation level of the phosphorescent dopant A is shallower than 5.3 eV.

  The highest electron occupation level (HOMO) level (also referred to as ionization potential) of the phosphorescent dopant A can be determined by using, for example, ultraviolet photoelectron spectroscopy (UPS). That is, the HOMO level can be measured by measuring the UPS of a thin film obtained by forming a single film of these compounds on a glass substrate.

  For example, a value measured by ESCA 5600 UPS (ultraviolet photoemission spectroscopy) manufactured by ULVAC-PHI Co., Ltd. can be used.

  In the white element of the present invention, a phosphorescent light emitter having a wavelength of light emission λmax other than 300 nm to 480 nm can be used together, and a white light emitting layer can be formed by combining these phosphorescent light emitters.

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

  The phosphorescent quantum yield can be measured by, for example, 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 emitter according to the present invention achieves the above phosphorescence quantum yield (0.01 or more) in any solvent. It only has to be done.

  There are two types of phosphorescent light emitting principles. One type is the recombination of carriers on the host compound to which carriers are transported, and an excited state of the host compound is generated. In another type, the phosphorescent emitter becomes a carrier trap, and carrier recombination occurs on the phosphorescent emitter, resulting in emission from the phosphorescent emitter. Although it is a carrier trap type in which light emission can be obtained, in any case, the energy of the excited state of the phosphorescent emitter is required to be lower than the energy of the excited state of the host compound.

  The phosphorescent luminescent material can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  The phosphorescent emitter according to the present invention is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex compound). ), Rare earth complexes, and most preferred are iridium compounds.

  Among the phosphorescent dopants according to the present invention, the phosphorescent dopant A has been described above. Specific examples of the compounds used as the phosphorescent dopant B and the phosphorescent dopant C are shown below. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

《Middle layer》
In the organic EL device of the present invention, when a plurality of light emitting layers are provided, a non-light emitting intermediate layer (also referred to as an undoped region) may be provided between the light emitting layers.

  The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 to 50 nm, and more preferably in the range of 3 to 10 nm, which suppresses interaction such as energy transfer between adjacent light emitting layers and is organic. This is preferable because a large load is not applied to the current-voltage characteristics of the EL element.

  The material used for the non-light emitting intermediate layer may be the same as or different from the host compound of the light emitting layer, but may be the same as the host material of at least one of the adjacent light emitting layers. preferable.

  The non-light emitting intermediate layer may contain a compound (for example, a host compound) common to the non-light emitting layers, and each of the common host materials (here, the common host material is used) means phosphorescence. (In which the physicochemical characteristics such as luminescence energy and glass transition point are the same, or the host compound has the same molecular structure, etc.) Thus, even if the voltage (current) is changed, the hole and electron injection balance can be easily maintained. Furthermore, by using a host material having the same physical characteristics or the same molecular structure as the host compound contained in each light-emitting layer in the undoped light-emitting layer, device fabrication, which is a major problem in conventional organic EL device fabrication, is achieved. The complexity can also be eliminated.

  Further, in order to optimally adjust the injection balance of holes and electrons, it is also preferable that the non-light emitting intermediate layer functions as a blocking layer described later, that is, a hole blocking layer and an electron blocking layer. .

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer can be provided as necessary, and may exist 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.

  An injection layer is a layer provided between an electrode and an organic layer in order to lower drive voltage and improve light emission luminance. For example, “Organic EL element and its forefront of industrialization (November 30, 1998, NTS Corporation) Issue) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123-166), which is described in detail, and has a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer). .

  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 Phthalocyanine buffer layer typified by (1), oxide buffer layer typified by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene, and the like. Moreover, it is also preferable to use the material described in Japanese translations of PCT publication No. 2003-519432 gazette.

  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 lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. .

  The buffer layer (injection layer) is preferably a very thin film, and although it depends on the material used, the film thickness is preferably in the range of 0.1 nm to 5 μm.

<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. 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 mentioned later can be used as a hole-blocking layer as needed.

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

  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 positive hole transport layer mentioned later can be used as an electron blocking layer as needed.

  The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

《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 one 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 further 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 two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 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-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004), JP-A-11-251067, J. MoI. Huang et. al. It is also possible to use a hole transport material that has a so-called p-type semiconducting property as described in the literature (Applied Physics Letters 80 (2002), p. 139), JP 2003-519432 A. it can. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

  For the hole transport layer, the hole transport material may be selected from, for example, vacuum deposition method, spin coating method, casting method, LB method (Langmuir-Blodget method), ink jet method, spray method, printing method, slot type coater method, etc. The film can be formed by a known thin film forming method. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

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

  Conventionally, when a single electron transport layer and a plurality of layers are used, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transmitting the generated electrons to the light-emitting layer, any material selected from conventionally known compounds can be selected and used. For example, nitro-substituted fluorene derivatives, diphenylquinone Derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material. 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, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metals of these metal complexes are In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.
For the electron transport layer, the above-mentioned electron transport material may be a known material such as a vacuum deposition method, a spin coat method, a cast method, an LB method (Langmuir-Blodget method), an ink jet method, a spray method, a printing method, or a slot type coater method. The film can be formed by a thin film forming method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

  In addition, an electron transport material that has n-type semiconductor properties doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport material having such n-type semiconductor properties because an element with lower power consumption can be produced.

《Support substrate》
The support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) applied to the organic EL element of the present invention is not particularly limited in the type of glass, plastic, etc., and may be transparent. It 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) and 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 polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned. An inorganic or organic film or a hybrid film of both may be formed on the surface of the resin film, and the water vapor permeability measured by a method according to JIS K 7129-1992 is 0.01 g / (m ² · 24 h · atm) or less, and the oxygen permeability measured by a method according to JIS K 7126-1992 is preferably 10 ⁻³ g / (m ² · 24 h) or less. The water vapor permeability is preferably a high barrier film of 10 ⁻³ g / (m ² · 24 h) or less, and both the water vapor permeability and the oxygen permeability are 10 ⁻⁵ g / (m ² · 24h) or less is more preferable.

  As a material for forming the barrier film, any material may be used as long as it 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 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 layers made of organic materials. 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, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the 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, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is also preferable.

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

<Sealing>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support substrate with an adhesive.

  The sealing member may be disposed so as to cover the display area of the organic EL element, and may be concave or flat. Moreover, 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 organic EL element can be thinned. Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ g / (m ² · 24 h) or less and a water vapor permeability of 10 ⁻³ g / (m ² · 24 h) or less. Moreover, it is more preferable that both the water vapor permeability and the oxygen permeability are 10 ⁻⁵ 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 a reactive vinyl group of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylate. be able to. Moreover, the 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 it like screen printing.

  In addition, it is also preferable to coat the electrode and the organic layer on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and form an inorganic or organic layer in contact with the support substrate to form a sealing film. it can. 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 the element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. it can. Furthermore, 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 is injected in the gas phase and the liquid phase. Is preferred. A vacuum can also be used. 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 (for example, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (for example, barium perchlorate) , Magnesium perchlorate, etc.), 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 outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when 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, etc. used for the sealing can be used. Is preferably used.

"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 an electrode substance include conductive transparent materials such as metals such as Au, 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. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method. ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. 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 in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

  In the present invention, as at least one electrode, for example, a metal (silver) nanoparticle or a stripe-shaped, mesh-shaped, or random mesh-shaped light-impermeable conductive portion and a transparent window containing silver nanowires. A transparent electrode having a structure in which a conductive polymer layer containing a π-conjugated conductive polymer and a polyanion, and preferably containing a hydrophilic polymer binder, is laminated on the auxiliary electrode composed of a part can be used. Since it can be formed by coating, there is a manufacturing advantage.

  Each of the auxiliary electrode and the conductive polymer layer has a thickness in the range of 0.2 to 2.0 μm.

  For forming a conductive portion having a stripe shape, mesh shape, or random network shape, a conductive layer (metal layer: as a metal material, for example, gold, silver, copper, iron, nickel, etc.) by vapor deposition, sputtering, plating, or the like. Chrome, etc.) and etching using a known photolithography method, and ink containing metal fine particles (nanoparticles) such as screen printing, gravure printing, and ink jet printing. For example, a printing method can be used. For example, ink using silver nanoparticles is used.

  A method of printing an ink containing metal fine particles in a desired shape by various printing methods is preferable because it is simple, has few foreign matters, and does not require special chemical treatment.

  As the metal fine particle-containing ink, known inks can be used. Examples of the metal fine particles include metal fine particles containing any one of silver, gold, copper, palladium, platinum, aluminum, nickel, and the like, or fine particles of an alloy containing this metal.

  These metal fine particles are coated with a film (coating material) such as an organic substance on the surface in order to improve dispersibility.

  The particle diameter of the conductive fine particles is preferably nanoparticles of 0.1 μm or less, and preferably 1 nm or more and 1 μm or less. If it exceeds 1 μm, the irregularities of the metal fine line pattern are large, which is disadvantageous for leakage. When the thickness is 0.1 μm or less, fusion between particles proceeds even at low temperature firing, and high conductivity is obtained.

  In order to use metal fine particles of 0.1 μm or less, it is preferable to use the fine metal particles in a state of being coated with an organic protective colloid. As this organic protective colloid, one having a decomposition temperature or boiling point in the range of 70 to 250 ° C. is used for low-temperature firing.

  As the organic protective colloid, it is preferable to use hydrocarbons having 3 to 18 carbon atoms.

  The organic protective colloid satisfying the above conditions is not particularly limited, but includes octylamine (boiling point 178 to 179 ° C.), 6-methyl-2-heptylamine (boiling point 154 to 156 ° C.), dibutylamine ( Boiling point 160-162 ° C), hexylamine (boiling point 130-132 ° C), dipropylamine (boiling point 105 ° C), diisopropylamine (boiling point 83-84 ° C), butylamine (boiling point 76-78 ° C), stearic acid (boiling point 232) 19.95 hPa), palmitic acid (boiling point 271.4 ° C .; 133 hPa), myristic acid (boiling point 250 ° C .; 133 hPa), lauric acid (boiling point 131 ° C .; 1.3 hPa), octanoic acid (boiling point 238 ° C.), hexane Acid (boiling point 206 ° C), butyric acid (boiling point 162-165 ° C), octadecadienoic acid (229-230) ) And the like can be exemplified.

  Further, the coating amount of the metal nanoparticles with the organic protective colloid is not particularly limited, but is preferably set in the range of 1 to 40 parts by mass with respect to 100 parts by mass of the metal nanoparticles.

  Also for the dispersion medium, in order to perform low-temperature firing, it is preferable to use hydrocarbons having 3 to 18 carbon atoms having a decomposition temperature or boiling point in the range of 70 to 250 ° C. Although not particularly limited, Boiling point 167 ° C; 20 hPa), lauryl alcohol (boiling point 258-265 ° C), undecanol (boiling point 129-131 ° C; 16 hPa), decanol (boiling point 220-235 ° C), nonanol (boiling point 214-216 ° C), octanol (boiling point 188) -198 degreeC) etc. can be illustrated and these can be used individually by 1 type, and can also use 2 or more types together.

  Among these, it is particularly preferable to use decanol as a dispersion medium. By using decanol as a dispersion medium, a silver paste suitable for drawing by screen printing or the like can be obtained.

  A silver paste can be prepared by blending and mixing the metal nanoparticles covered with the organic protective colloid, the silver filler, and the dispersion medium. Organic protective colloid covering metal nanoparticles also plays a role as a binder, so it is not necessary to add a binder, and a silver paste can be prepared with only three components: metal nanoparticles, silver filler, and dispersion medium. It is.

  The silver paste thus prepared can be applied to the surface of a substrate or the like by a conventionally known method such as screen printing, ink jet printing, dipping, applicator application, spin coat application.

(Random network structure)
As a random network structure, for example, a method for spontaneously forming a disordered network structure of conductive fine particles by applying and drying a liquid containing metal fine particles as described in JP-T-2005-530005 Can be used.

  As another method, for example, a method of forming a random network structure of metal nanowires by applying and drying a coating solution containing metal nanowires as described in JP-T-2009-505358 can be used.

  The metal nanowire refers to a fibrous structure having a metal element as a main component. In particular, the metal nanowire in the present invention means a large number of fibrous structures having a minor axis from the atomic scale to the nm size.

  As the metal nanowire, in order to form a long conductive path with one metal nanowire, the average length is preferably 3 μm or more, more preferably 3 to 500 μm, and particularly preferably 3 to 300 μm. In addition, the relative standard deviation of the length is preferably 40% or less. Moreover, although there is no restriction | limiting in particular in an average breadth, it is preferable that it is small from a transparency viewpoint, and the larger one is preferable from a conductive viewpoint. The average minor axis of the metal nanowire is preferably 10 to 300 nm, and more preferably 30 to 200 nm. In addition, the relative standard deviation of the minor axis is preferably 20% or less.

  As the metal used for the metal nanowire, copper, iron, cobalt, gold, silver or the like can be used, but silver is preferable from the viewpoint of conductivity. In addition, although a single metal may be used, in order to achieve both conductivity and stability (sulfurization, oxidation resistance, and migration resistance of metal nanowires), the main metal and one or more other metals May be included in any proportion.

  There is no restriction | limiting in particular in the manufacturing method of metal nanowire, For example, well-known means, such as a liquid phase method and a gaseous-phase method, can be used. Moreover, there is no restriction | limiting in particular in a specific manufacturing method, A well-known manufacturing method can be used. For example, as a method for producing silver nanowires, Adv. Mater. 2002, 14, p. 833-837, Chem. Mater. 2002, 14, p. 4736 to 4745, a method for producing gold nanowires is disclosed in JP-A-2006-233252, a method for producing copper nanowires is disclosed in JP-A-2002-266007, and a method for producing cobalt nanowires is disclosed in JP-A-2004-149871. Etc. can be referred to. In particular, the above-described method for producing silver nanowires can be preferably applied because silver nanowires can be easily produced in an aqueous solution, and the conductivity of silver is maximum in metals.

Conductive polymer-containing layer << conductive polymer >>
The conductive polymer is a conductive polymer comprising a π-conjugated conductive polymer and a polyanion. Such a conductive polymer can be easily produced by subjecting a precursor monomer that forms a π-conjugated conductive polymer described later to chemical oxidative polymerization in the presence of an appropriate oxidizing agent, an oxidation catalyst, and a polyanion described later.

《Π-conjugated conductive polymer》
The π-conjugated conductive polymer used in the present invention is not particularly limited, and includes polythiophenes (including basic polythiophenes, the same applies hereinafter), polypyrroles, polyindoles, polycarbazoles, polyanilines, polyacetylenes, polyfurans. , Polyparaphenylene vinylenes, polyazulenes, polyparaphenylenes, polyparaphenylene sulfides, polyisothianaphthenes, polythiazyl chain conductive polymers can be used. Of these, polythiophenes and polyanilines are preferable from the viewpoint of conductivity, transparency, stability, and the like. Most preferred is polyethylene dioxythiophene.

[Π-conjugated conductive polymer precursor monomer]
The precursor monomer has a π-conjugated system in the molecule, and a π-conjugated system is formed in the main chain even when polymerized by the action of an appropriate oxidizing agent. Examples thereof include pyrroles and derivatives thereof, thiophenes and derivatives thereof, anilines and derivatives thereof, and the like.

  Specific examples of the precursor monomer include pyrrole, 3-methylpyrrole, 3-ethylpyrrole, 3-n-propylpyrrole, 3-butylpyrrole, 3-octylpyrrole, 3-decylpyrrole, 3-carboxylpyrrole, 3- Hydroxypyrrole, 3-methoxypyrrole, 3-hexyloxypyrrole, thiophene, 3-methylthiophene, 3-ethylthiophene, 3-butylthiophene, 3-hexylthiophene, 3-octylthiophene, 3-dodecylthiophene, 3-bromothiophene 3-chlorothiophene, 3-iodothiophene, 3-cyanothiophene, 3-phenylthiophene, 3,4-dimethylthiophene, 3,4-dibutylthiophene, 3-hydroxythiophene, 3-methoxythiophene, 3-ethoxythiophene, 3- Toxithiophene, 3-hexyloxythiophene, 3-heptyloxythiophene, 3-octyloxythiophene, 3-decyloxythiophene, 3-dodecyloxythiophene, 3-octadecyloxythiophene, 3,4-dihydroxythiophene, 3,4- Dimethoxythiophene, 3,4-diethoxythiophene, 3,4-dipropoxythiophene, 3,4-dibutoxythiophene, 3,4-dihexyloxythiophene, 3,4-diheptyloxythiophene, 3,4-dioctyloxy Thiophene, 3,4-didecyloxythiophene, 3,4-didodecyloxythiophene, 3,4-ethylenedioxythiophene, 3,4-propylenedioxythiophene, 3,4-butenedioxythiophene, 3-methyl -4-methoxy Offene, 3-methyl-4-ethoxythiophene, 3-carboxythiophene, 3-methyl-4-carboxythiophene, 3-methyl-4-carboxyethylthiophene, 3-methyl-4-carboxybutylthiophene, aniline, 2-methyl Aniline, 3-isobutyl aniline, 2-aniline sulfonic acid, 3-aniline sulfonic acid, etc. are mentioned.

《Polyanion》
The polyanion is a substituted or unsubstituted polyalkylene, a substituted or unsubstituted polyalkenylene, a substituted or unsubstituted polyimide, a substituted or unsubstituted polyamide, a substituted or unsubstituted polyester, and a copolymer thereof. It consists of a structural unit having a group and a structural unit having no anionic group.

  This polyanion is a solubilized polymer that solubilizes the π-conjugated conductive polymer in a solvent. The anion group of the polyanion functions as a dopant for the π-conjugated conductive polymer, and improves the conductivity and heat resistance of the π-conjugated conductive polymer.

  The anion group of the polyanion may be a functional group capable of undergoing chemical oxidation doping to the π-conjugated conductive polymer. Among them, from the viewpoint of ease of production and stability, a monosubstituted sulfate group, A monosubstituted phosphate group, a phosphate group, a carboxy group, a sulfo group and the like are preferable. Furthermore, from the viewpoint of the doping effect of the functional group on the π-conjugated conductive polymer, a sulfo group, a monosubstituted sulfate group, and a carboxy group are more preferable.

  Specific examples of polyanions include polyvinyl sulfonic acid, polystyrene sulfonic acid, polyallyl sulfonic acid, polyacrylic acid ethyl sulfonic acid, polyacrylic acid butyl sulfonic acid, poly-2-acrylamido-2-methylpropane sulfonic acid, polyisoprene sulfone. Examples include acid, polyvinyl carboxylic acid, polystyrene carboxylic acid, polyallyl carboxylic acid, polyacryl carboxylic acid, polymethacryl carboxylic acid, poly-2-acrylamido-2-methylpropane carboxylic acid, polyisoprene carboxylic acid, polyacrylic acid and the like. . These homopolymers may be sufficient and 2 or more types of copolymers may be sufficient.

  Moreover, the polyanion which has F in a compound may be sufficient. Specifically, Nafion (made by Dupont) containing a perfluorosulfonic acid group, Flemion (made by Asahi Glass Co., Ltd.) made of perfluoro vinyl ether containing a carboxylic acid group, and the like can be mentioned.

  Among these, when a compound having a sulfonic acid is formed by applying and drying a conductive polymer-containing layer, when subjected to a heat treatment at a temperature of 100 ° C. or more and 200 ° C. or less for 5 minutes or more, It is more preferable because the cleaning resistance and solvent resistance of the coating film are remarkably improved.

  Furthermore, among these, polystyrene sulfonic acid, polyisoprene sulfonic acid, polyacrylic acid ethylsulfonic acid, and polyacrylic acid butylsulfonic acid are preferable. These polyanions have high compatibility with the binder resin, and can further increase the conductivity of the obtained conductive polymer.

  The degree of polymerization of the polyanion is preferably in the range of 10 to 100,000 monomer units, and more preferably in the range of 50 to 10,000 from the viewpoint of solvent solubility and conductivity.

  Examples of methods for producing polyanions include a method of directly introducing an anionic group into a polymer having no anionic group using an acid, a method of sulfonating a polymer having no anionic group with a sulfonating agent, and anionic group-containing polymerization. And a method of production by polymerization of a functional monomer.

  Examples of the method for producing an anionic group-containing polymerizable monomer by polymerization include a method for producing an anionic group-containing polymerizable monomer in a solvent by oxidative polymerization or radical polymerization in the presence of an oxidizing agent and / or a polymerization catalyst. Specifically, a predetermined amount of the anionic group-containing polymerizable monomer is dissolved in a solvent, kept at a constant temperature, and a solution in which a predetermined amount of an oxidizing agent and / or a polymerization catalyst is dissolved in the solvent is added to the predetermined amount. React with time. The polymer obtained by the reaction is adjusted to a certain concentration by the solvent. In this production method, an anionic group-containing polymerizable monomer may be copolymerized with a polymerizable monomer having no anionic group.

  The oxidizing agent, oxidation catalyst, and solvent used in the polymerization of the anionic group-containing polymerizable monomer are the same as those used in the polymerization of the precursor monomer that forms the π-conjugated conductive polymer.

  When the obtained polymer is a polyanionic salt, it is preferably transformed into a polyanionic acid. Examples of the method for converting to an anionic acid include an ion exchange method using an ion exchange resin, a dialysis method, an ultrafiltration method, and the like. Among these, the ultrafiltration method is preferable from the viewpoint of easy work.

  A commercially available material can be preferably used for such a conductive polymer. For example, a conductive polymer (abbreviated as PEDOT-PSS) composed of poly (3,4-ethylenedioxythiophene) and polystyrenesulfonic acid is described in H.C. C. It is commercially available from Starck as the CLEVIOS series, from Aldrich as PEDOT-PASS 483095, 560598, and from Nagase Chemtex as the Denatron series. Polyaniline is also commercially available from Nissan Chemical as the ORMECON series. In the present invention, such an agent can also be preferably used.

  A water-soluble organic compound may be contained as the second dopant. There is no restriction | limiting in particular in the water-soluble organic compound which can be used by this invention, It can select suitably from well-known things, For example, an oxygen containing compound is mentioned suitably.

  The oxygen-containing compound is not particularly limited as long as it contains oxygen, and examples thereof include a hydroxy group-containing compound, a carbonyl group-containing compound, an ether group-containing compound, and a sulfoxide group-containing compound. Examples of the hydroxy group-containing compound include ethylene glycol, diethylene glycol, propylene glycol, trimethylene glycol, 1,4-butanediol, and glycerin. Among these, ethylene glycol and diethylene glycol are preferable. Examples of the carbonyl group-containing compound include isophorone, propylene carbonate, cyclohexanone, and γ-butyrolactone. Examples of the ether group-containing compound include diethylene glycol monoethyl ether. Examples of the sulfoxide group-containing compound include dimethyl sulfoxide. These may be used alone or in combination of two or more, but at least one selected from dimethyl sulfoxide, ethylene glycol, and diethylene glycol is preferably used.

《Hydrophilic polymer binder》
In the present invention, by using a hydrophilic polymer binder in combination with the conductive polymer-containing layer, it becomes possible to increase the film thickness without reducing the transmittance, and by embedding foreign matter or the like attached to the surface. It becomes possible to suppress a short circuit between them, which is a preferred embodiment. The hydrophilic polymer binder used in the present invention is not particularly limited as long as it is a polymer that can be dissolved or dispersed in an aqueous solvent (described later). For example, polyester resin, acrylic resin, polyurethane resin, acrylic urethane type Examples thereof include a resin, a polycarbonate resin, a cellulose resin, a polyvinyl acetal resin, and a polyvinyl alcohol resin. Specific examples of the compound include Vylonal MD1200, MD1400, MD1480 (manufactured by Toyobo Co., Ltd.) as polyester resins.

  As the hydrophilic polymer binder according to the present invention, a compound having a group that reacts with a crosslinking agent described later is more preferable because a stronger film is formed. As such a hydrophilic polymer binder, a group that reacts with the crosslinking agent varies depending on the crosslinking agent, and examples thereof include a hydroxy group, a carboxyl group, and an amino group. Among these, it is most preferable to have a hydroxy group in the side chain.

  Specific compounds of the hydrophilic polymer binder according to the present invention include polyvinyl alcohol PVA-203, PVA-224, PVA-420 (manufactured by Kureha), hydroxypropylmethylcellulose 60SH-06, 60SH-50, 60SH. -4000, 90SH-100 (above, Shin-Etsu Chemical Co., Ltd.), methylcellulose SM-100 (Shin-Etsu Chemical Co., Ltd.), cellulose acetate L-20, L-40, L-70 (above, Daicel Chemical Industries, Ltd.) Carboxymethylcellulose CMC-1160 (manufactured by Daicel Chemical Industries), hydroxyethyl cellulose SP-200, SP-600 (manufactured by Daicel Chemical Industries, Ltd.), alkyl acrylate copolymer Jurimer AT-210, AT-510 (and above, Manufactured by Toagosei Co., Ltd.), polyhydroxyethyla Relate, mention may be made of polyhydroxyethyl methacrylate.

  In particular, when the hydrophilic polymer binder contains a certain amount of the polymer (A), it is possible to improve the conductivity of the conductive polymer-containing layer by using this compound without using the second dopant. In addition, compatibility with the conductive polymer is good, and high transparency and smoothness can be achieved. Furthermore, when the polyanion has a sulfo group, if the polymer (A) is used, the sulfo group effectively acts as a dehydration catalyst, and a dense cross-linked layer can be formed without using an additional agent such as a cross-linking agent. This is a more preferred embodiment because it can be formed.

  The main copolymerization component of the polymer (A) is a monomer represented by the following (a1) to (a3), and 50 mol% or more of the copolymerization component is any of the following (a1) to (a3), or A copolymer having a total of 50 mol% or more of the following components (a1) to (a3). More preferably, the sum of the components (a1) to (a3) below is 80 mol% or more, and may be a homopolymer formed from any one of the following monomers (a1) to (a3), It is also a preferred embodiment.

In the formula, X _{1 to} X _{3 each} represents a hydrogen atom or a methyl group, and R _{1 to} R ₃ each represents an alkylene group having 5 or less carbon atoms. p, m, and n represent the composition ratio (mol%), and 50 ≦ p + m + n ≦ 100.

  In the polymer (A), other monomer components may be copolymerized as long as they are soluble in an aqueous solvent, but a monomer component having high hydrophilicity is more preferable. The polymer (A) preferably has a content of 1000 or less in the number average molecular weight of 0 to 5%.

  In the number average molecular weight of the polymer (A), the content of 1000 or less is 0 to 5% or less, such as reprecipitation method, preparative GPC, synthesis of monodisperse polymer by living polymerization, etc. Methods that remove components or suppress the formation of low molecular weight components can be used. In the reprecipitation method, the polymer is dissolved in a solvent in which the polymer can be dissolved and dropped into a solvent having a lower solubility than the solvent in which the polymer is dissolved, thereby precipitating the polymer and removing low molecular weight components such as monomers, catalysts, and oligomers. It is a method to do. In addition, preparative GPC is, for example, recycle preparative GPCLC-9100 (manufactured by Japan Analytical Industrial Co., Ltd.), polystyrene gel column, and can be divided by molecular weight by passing the solution in which the polymer is dissolved through the column. It is a method that can be cut. In the living polymerization, the generation of the starting species does not change with time, and there are few side reactions such as termination reaction, and a polymer having a uniform molecular weight can be obtained. Since the molecular weight can be adjusted by the addition amount of the monomer, for example, if a polymer having a molecular weight of 20,000 is synthesized, the formation of a low molecular weight body can be suppressed. The reprecipitation method and living polymerization are preferable from the viewpoint of production suitability.

The number average molecular weight and the weight average molecular weight of the hydrophilic polymer binder of the present invention can be measured by generally known gel permeation chromatography (GPC). The molecular weight distribution can be expressed by a ratio of (weight average molecular weight / number average molecular weight). The solvent to be used is not particularly limited as long as the hydrophilic polymer binder dissolves, and THF, DMF, and CH ₂ Cl ₂ are preferable, THF and DMF are more preferable, and DMF is more preferable. The measurement temperature is not particularly limited, but 40 ° C. is preferable.

  The molecular weight of the polymer (A) according to the present invention is preferably in the range of 3,000 to 2,000,000, more preferably 4,000 to 500,000, still more preferably 5,000 to 100,000. The molecular weight distribution of the polymer (A) is preferably 1.01 to 1.30, more preferably 1.01 to 1.25.

  In the distribution obtained by GPC, the content having a number average molecular weight of 1000 or less was converted by multiplying the area having a number average molecular weight of 1000 or less and dividing by the area of the entire distribution.

  The living radical polymerization solvent is inactive under the reaction conditions and is not particularly limited as long as it can dissolve the monomer and the polymer to be formed, but a mixed solvent of an alcohol solvent and water is preferable. The living radical polymerization temperature varies depending on the initiator used, but is generally -10 to 250 ° C, preferably 0 to 200 ° C, more preferably 10 to 100 ° C.

[Formation of conductive polymer-containing layer]
The conductive polymer-containing layer is, for example, applied and dried with a coating liquid containing at least a conductive polymer containing a π-conjugated conductive polymer component and a polyanion component, a hydrophilic polymer binder, and a solvent. Can be formed.

  As the solvent, an aqueous solvent can be preferably used. Here, the aqueous solvent represents a solvent in which 50% by mass or more is water. Of course, pure water containing no other solvent may be used. The component other than water in the aqueous solvent is not particularly limited as long as it is a solvent compatible with water, but an alcoholic solvent can be preferably used, and isopropyl alcohol having a boiling point relatively close to water can be used. This is advantageous for the smoothness of the film to be formed.

  As coating methods, roll coating method, bar coating method, dip coating method, spin coating method, casting method, die coating method, blade coating method, bar coating method, gravure coating method, curtain coating method, spray coating method, doctor coating method A letterpress (letter) printing method, a stencil (screen) printing method, a lithographic (offset) printing method, an intaglio (gravure) printing method, a spray printing method, an ink jet printing method, and the like can be used.

  The dry film thickness of the conductive polymer-containing layer is preferably 30 to 2000 nm. The conductive layer according to the present invention preferably has a conductivity of 100 nm or more because the decrease in conductivity is large in the region of less than 100 nm, and more preferably 200 nm or more from the viewpoint of further improving the leakage prevention effect. Further, it is more preferably 1000 nm or less from the viewpoint of maintaining high transmittance.

  After the application, a drying treatment is appropriately performed in order to volatilize the solvent. Although there is no restriction | limiting in particular as conditions of a drying process, It is preferable to dry-process at the temperature of the range which does not damage a board | substrate and a conductive polymer content layer. For example, the drying process can be performed at 80 to 150 ° C. for 10 seconds to 10 minutes.

  Further, when the polyanion has a sulfo group and contains the polymer (A) as a hydrophilic polymer binder, it is preferable to perform an additional heat treatment for the purpose of accelerating the crosslinking of the layer by the dehydration reaction of the hydroxyl group. Although there is no restriction | limiting in the conditions of heat processing, It is preferable to dry-process at the temperature of the range which does not damage a board | substrate or a conductive polymer content layer. For example, the drying process can be performed at 80 to 150 ° C. for 2 minutes to 120 minutes. Moreover, you may perform the process for about 10 to 200 hours for a long time at the comparatively low temperature of about 40 to 100 degreeC.

  As another electrode, a transparent and conductive carbon nanotube-containing coating containing carbon nanotubes described in Japanese Patent No. 3665969 can be used as one transparent electrode.

  In this electrode coating, a first dispersion containing at least carbon nanotubes and a solvent is applied to the surface of the substrate, the solvent of the first dispersion is removed, and the carbon nanotubes are made into a three-dimensional network structure. This is a carbon nanotube coating in which a second dispersion containing at least a resin and a solvent is applied thereon and the second dispersion is infiltrated into the three-dimensional network structure of carbon nanotubes.

  Carbon nanotubes are well known and have conventional meanings, but carbon nanotubes include linear and curved multi-walled carbon nanotubes (MWNT), linear and curved double-walled carbon nanotubes (DWNT), and linear and curved single-walled carbon nanotubes ( SWNT), as well as various compositions in the form of these carbon nanotubes, as well as common by-products involved in carbon nanotube production as described in US Pat. Nos. 6,333,016 and WO 01/92381 .

  In preferred embodiments, the carbon nanotubes have an outer diameter of less than 3.5 nm. In another preferred embodiment, the carbon nanotubes of the present invention have an outer diameter of less than 3.0 nm. In another preferred embodiment, the carbon nanotubes of the present invention have an outer diameter of about 0.5 to about 2.5 nm. In another preferred embodiment, the carbon nanotube has an outer diameter of about 0.5 to about 1.5 nm. In another preferred embodiment, the carbon nanotube has an outer diameter of about 0.5 to about 1.0 nm. The aspect ratio can be between 10 and 2000.

  In a preferred embodiment, the carbon nanotube comprises a single-walled SWNT-containing material. SWNTs can be produced by a number of methods, such as laser ablation of carbon targets, hydrocarbon decomposition, and arcing between two graphite electrodes. For example, US Pat. No. 5,424,054 granted to Bethune et al. Describes a method for producing single-walled carbon nanotubes by contacting carbon vapor with a cobalt catalyst. Carbon vapor is generated by electric arc heating of solid carbon, which can be amorphous carbon, graphite, activated carbon, decolorizing coal, or mixtures thereof. Examples of another heating method of carbon include laser heating, electron beam heating, and high frequency induction heating. In addition, for example, a method for producing single-walled carbon nanotubes by simultaneously vaporizing a graphite rod and a transition metal with a high-temperature laser is known. In addition, for example, a method for producing single-walled carbon nanotubes by vaporizing a graphite rod containing a small amount of transition metal with a laser in an oven at about 1200 ° C. is known. It is reported to generate at a rate. US Pat. No. 6,221,330, the entire contents of which are incorporated herein, discloses a method for producing single-walled carbon nanotubes using a gaseous carbon feedstock and an unsupported catalyst.

  SWNTs are very flexible and naturally aggregate to form a carbon nanotube rope. By forming the SWNT rope in the coating or film, the electrical conductivity becomes very high with a very small content, so that excellent transparency is obtained and low haze (cloudiness value) is obtained.

  These electrode coatings provide excellent conductivity and transparency with a low carbon nanotube content. In a preferred embodiment, the carbon nanotubes in the coating are present from about 0.001 to about 1% by weight. More preferably, carbon nanotubes are present in the film in an amount of about 0.01 to about 0.1%, so that excellent transparency is obtained and low haze is achieved.

The surface resistance of this coating is acceptable if it is less than 10 ¹⁰ Ω / □, preferably less than 10 ⁴ Ω / □, and the transparent low visibility coating is usually less than 10 ³ Ω / □, preferably 10 Less than ² Ω / □. Therefore, preferably the surface resistance of the coating is in the range of about 10 ^-2 to 100 Ω / □. Also, the volume resistance of the coating of the present invention is in the range of about 10 ⁻² Ω · cm to about 10 ¹⁰ Ω · cm. The volume resistance is defined by ASTM D4496-87 and ASTM D257-99.

  This electrode coating exhibits excellent transparency and low haze. For example, the total light transmittance is at least about 60%, and the haze value of visible light is about 2.0% or less. In a preferred embodiment, the haze value of the film of the present invention is 0.5% or less.

  In a preferred embodiment, the total light transmittance of the coating is about 85% or more, more preferably 90% or more, more preferably 95% or more. In another preferred embodiment, the haze value is less than 1%, preferably less than 0.5%.

Total light transmission means the percentage of energy transmitted through a film of the electromagnetic spectrum with a wavelength of less than 1 × 10 ⁻² cm and thus necessarily includes the wavelength of visible light.

  The thickness of the coating of the present invention ranges from a moderate thickness to a very thin thickness.

  For example, the film of the present invention can be between about 0.5 nm and about 100 μm thick.

  The coating of the present invention comprises a resin polymer material. The polymeric material can be selected from a wide range of natural or synthetic polymeric resins. The individual polymers can be selected depending on strength, structure, and design needs in the desired application. In a preferred embodiment, the polymeric material comprises a material selected from the group consisting of thermoplastic resins, thermosetting polymers, elastomers, conductive polymers, ceramic hybrid polymers, and combinations thereof. In another preferred embodiment, the polymeric material is polyethylene, polypropylene, polyvinyl chloride, styrene resin, polyurethane, polyimide, polycarbonate, polyethylene terephthalate, cellulose, gelatin, chitin, polypeptide, polysaccharide, polynucleotide, and mixtures thereof. A material selected from the group consisting of: In another preferred embodiment, the polymeric material comprises a material selected from the group consisting of a ceramic composite polymer, a phosphine oxide, and a chalcogenide.

  The coating can be easily formed and applied to the substrate as a dispersion of carbon nanotubes alone in a solvent such as acetone, water, ether, and alcohol. The solvent can be removed by an ordinary method such as air drying, heating, or reduced pressure to form a desired carbon nanotube film. The coating can be applied by other known methods such as spray painting, dip coating, spin coating, knife coating, kiss coating, gravure coating, screen printing, ink jet printing, pad printing, other types of printing, or roll coating Can do.

  A coating of the present invention comprising carbon nanotubes mixed with an appropriate amount of polymer can be readily synthesized. Can be implemented using conventional mixing and processing methods, including but not limited to conventional extrusion, multi-die extrusion, pressure lamination, etc., used to introduce carbon nanotubes into polymers Other possible methods are also mentioned.

  Carbon nanotubes may be distributed substantially uniformly throughout the polymer material, but the amount increases or decreases (eg, concentration from the outer surface to the center of the material or from one side to the other). ) May exist in a state where there is a gradient. Alternatively, the carbon nanotubes may be dispersed as an outer skin layer or an inner layer, in which case an inner laminated structure is formed.

  In a preferred form, the multilayer structure has alternating layers of carbon nanotube-containing layers and carbon nanotube-free layers.

  The dispersion of the present invention includes a plasticizer, a softening agent, a filler, a reinforcing agent, a processing aid, a stabilizer, an antioxidant, a dispersing agent, a binder, a crosslinking agent, a colorant, a UV absorber, or a charge adjusting agent. These materials can optionally be further included.

  These dispersions can further include other conductive organic materials, inorganic materials, or combinations of these materials. Examples of the conductive organic material include buckyball, carbon black, fullerene, carbon nanotubes having an outer diameter of more than about 3.5 nm, and particles including combinations and mixtures thereof. Conductive materials include indium tin oxide, antimony tin oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, and combinations and mixtures thereof. Preferred dispersions can also include fluids, gelatin, ionic compounds, semiconductors, solids, surfactants, and combinations and mixtures thereof.

"cathode"
As the cathode, a material having a 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. The sheet resistance as a 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 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.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described.

  First, a desired electrode material, for example, a thin film made of a material for an anode is formed on a suitable support substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm, thereby producing an anode. To do. Next, an organic compound thin film of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, is formed thereon.

  As a method for thinning the organic compound thin film, as described above, the vapor deposition method, the wet process (spin coating method, casting method, ink jet method, printing method, LB method (Langmuir-Blodgett method), spray method, printing method, However, vacuum deposition, spin coating, ink-jet, printing, and slot-type coater methods are particularly preferred from the standpoint that a homogeneous film is easily obtained and pinholes are not easily formed. preferable. Further, different film forming methods may be applied for each layer. When employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C., a vacuum degree of 10 −6 Pa to 10 −2 Pa, a vapor deposition rate of 0.01 nm / It is desirable to select appropriately within the range of from 2 to 50 nm / second, the substrate temperature from -50 to 300 ° C., and the film thickness from 0.1 to 5 μm, preferably from 5 to 200 nm. After forming these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element 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 necessary to consider that the work is performed in a dry inert gas atmosphere.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode 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 of about 2 V to 40 V with the anode as + and the cathode as-. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  An organic electroluminescence element emits light inside a layer having a higher refractive index than air (refractive index of about 1.6 to 2.1), and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said that there is no. 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 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 side surface of the device.

  As a technique 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 transparent substrate and the air interface (for example, US Pat. No. 4,774,435), A method for improving efficiency by providing light condensing property (for example, JP-A-63-314795), a method for forming a reflective surface on a side surface of an element (for example, JP-A-1-220394), a substrate, etc. A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the substrate and the light emitter (for example, Japanese Patent Application Laid-Open No. 62-172691), lower refraction than the substrate between the substrate and the light emitter A method of introducing a flat layer having a refractive index (for example, Japanese Patent Application Laid-Open No. 2001-202827), and a method of forming a diffraction grating between any one of the substrate, the transparent electrode layer and the light emitting layer (including between the substrate and the outside world) ( JP-A-11 No. 283,751 Publication), and the like.

  In the present invention, these methods can be used in combination with the organic electroluminescence device of the present invention, but 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, A method of forming a diffraction grating between any layers of the transparent 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 low refractive index medium 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 about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Furthermore, it is preferable that it is 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 that causes total reflection or in any medium has a feature that the effect of improving the light extraction efficiency is high. 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 or second-order diffraction. The light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating into any layer or medium (in the transparent substrate or transparent electrode). , Trying to extract light 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. 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.

  The position where the diffraction grating is introduced may be in any 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 about 1/2 to 3 times the wavelength of light in the medium. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

  The organic electroluminescence device of the present invention is processed to provide a structure on the microlens array, for example, on the light extraction side of the support substrate (substrate), or combined with a so-called condensing sheet, for example, in a specific direction, By condensing in the front direction with respect to the element light emitting surface, 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 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, a substrate may be formed with a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm, or the apex angle is rounded and the pitch is changed randomly. Other shapes may also be used.

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

<Display device>
A display device to which the organic EL element of the present invention is applied will be described.

  The organic EL element of the present invention is used for a multicolor or white display device. In the case of a multicolor or white 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, slot coater, or the like. When patterning is performed only on the light-emitting layer, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  Further, the cathode, the electron transport layer, the hole blocking layer, and the light emitting layer unit (having at least three layers of the above light emitting layers A, B, and C, and a non-light emitting intermediate layer between the light emitting layers) It is also possible to produce the hole transport layer and the anode in this order. When a DC voltage is applied to the multicolor or white display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. 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.

《Lighting device》
A lighting device to which the organic EL element of the present invention is applied will be described.

  The organic EL device of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a display device that directly recognizes a still image or a moving image. (Display) may be used. 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.

  In the white organic electroluminescent element used for this invention, you may pattern by a metal mask, the inkjet printing method, etc. at the time of film forming as needed. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned. The light emitting dopant used in the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is adapted so as to conform to the wavelength range corresponding to the CF (color filter) characteristics. Any one of known light-emitting dopants may be selected and combined, or combined with the light extraction and / or light collecting sheet according to the present invention to be whitened.

  Thus, the white organic EL element of the present invention is described in claim 7 by combining the CF (color filter) and arranging the element and the driving transistor circuit in accordance with the CF (color filter) pattern. In this way, white light extracted from the organic electroluminescence device is used as a backlight, and blue light, green light, and red light are obtained through a blue filter, a green filter, and a red filter. An organic electroluminescence display is preferable and preferable.

<< Industrial field to which the organic EL element of the present invention is applied >>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. Examples of 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, and light sources for optical sensors. Although it is not limited to this, it can be effectively used for backlights of various display devices combined with color filters, light diffusion plates, light extraction films, etc., and as a light source for illumination.

  Taking advantage of the characteristics of the organic EL device of the present invention, it can be applied to various lighting fixtures and light emitting displays as shown below.

[For product display and display]
For product display and display, there are store product display, freezer / refrigerated showcase, light up of exhibits in museums, art galleries, exhibition halls, vending machines, play tables, traffic advertisements, etc.

  Store merchandise displays include decorative displays, showcases, POPs and signs for the store itself. Among stores, high-end brand shops, precious metals, fashion, high-end restaurants, and other stores that place emphasis on the brand image have a great influence on the store image that lighting gives, so lighting has been selected with strong attention This is a field. By using organic EL, the space for the light source and equipment can be omitted in the field of indirect lighting, which has created an atmosphere by devising the structure of the building so that the light source can not be seen directly, and no complicated structure is required The space between the light source and the diffusion plate can be omitted because the shape of the light source cannot be seen through when creating diffused light in interiors or signs, and so on. Also, as a tool for changing the image of the store, it takes advantage of the feature that it is a light source that does not take up space such as display shelves, floors, fixtures, etc., and it has design freedom, easy workability, and easy There is an advantage that it can be adopted.

  Frozen and refrigerated showcases are placed in supermarkets and convenience stores to make fresh foods such as vegetables, fruits, fresh fish, meat, etc. full of beauty and freshness, making them easier to see, vivid, and easier to take. Lighting equipment is another important component. By using an organic EL light source, low temperature emission has little effect on the cooling function, and since it is thin, the light source space can be greatly reduced, so the storage space can be expanded, and it is easy to select food with a smart design. It can be made easier. In addition, it can appeal to consumers with colored light that makes it easy to understand the goodness of food, contributing to sales.

  In order to light up exhibits in museums, art galleries, exhibition halls, etc., it is necessary to select a light source that is suitable for the conditions of use from the viewpoint of visual recognition and sunburn. Has been developed. Since the organic EL light source does not contain ultraviolet rays and the calorific value is low, there is no adverse effect on the exhibit, it is uniform glare with the surface light source, and it is possible to faithfully appreciate the display as it is with high color rendering. it can. In addition, since a large light source device is not required, it is possible to focus only on the exhibits without the need for extra equipment protruding in the field of view. Also, in large-scale exhibition halls such as shows, large-sized electric decorations that attract attention can be assembled relatively easily due to their lightweight and thin features.

  Vending machines use light sources for push buttons, product samples, and posters on the front of the vending machine. It is a field where the advantage of organic EL that does not take up a thin light source space can be utilized because the space for the additional function to be taken in and the storage space are combined with the size of the entire device, especially on the outlet Needs are high in poster space. In recent years, there are many devices that have game characteristics such as hit / miss along with sales, and it is possible to make further use of the benefits by installing a light source (video display) with a pixel control function on the front poster. Can do.

  There are pachinko and pachislots at the playground. At these playgrounds, it is most important for users to experience and enjoy amusement (games, gambling, etc.). Although there is a merit of thinness that can reduce the thickness of one device by thinning the light source, like the vending machine, it can make further use of the merit by installing a light source (video display) with a pixel control function. Can do.

  Traffic advertisements include posters and signboards in public spaces, internal posters and screens such as trains and buses, and advertisements on the body. In particular, posters and billboards are box-type fluorescent lamps using a backlight, and the box itself can be made thinner and lighter by changing to organic EL.

  In addition, by thinning the box for hanging signboards, dust and dirt can be prevented from being accumulated, and bird damage caused by birds can be prevented.

[Built-in lighting for interior, furniture and building materials]
In terms of architecture, a combination of floors, walls, ceilings, etc. and lighting is called “architectural lighting”. Typical examples of “architectural lighting” include cornice lighting, troffer lighting, cove lighting, light ceiling, and louver ceiling, depending on the method. These require lighting sources to be built into the ceiling, walls and floors, extinguish their presence and signs as lighting, and the building materials themselves to emit light.

  Light sources using organic EL elements are the most suitable light sources for “architecture lighting” due to their thinness, lightness, color adjustment, and design variability, and can be applied to interiors, furniture, and fixtures. It is. Conventionally, such architectural lighting, which has been used only in stores and museums, can be extended to ordinary houses by developing organic EL light sources, and new demand can be found.

  In commercial facilities, organic EL light sources are used in semi-underground stores, arcade ceilings, etc., and by changing the brightness and color temperature of illumination, it is possible to construct an optimal commercial space that is not affected by the weather or day and night.

  Examples of interior / furniture / furniture include desks and chairs, storage of cupboards / shoeboxes / lockers, vanities, altars, bed lights, footlights, handrails, doors, shoji screens, shojis, etc. It is not limited to that.

  On the other hand, it is possible to switch between transparent and opaque by using a transparent electrode for the organic EL light source and turning it off / emitting light. As a result, it can be used as any window, door, curtain, blind, and partition.

[Automotive lighting, luminous display]
For automobiles, organic EL elements can be used for external lighting fixtures and light-emitting display bodies, in-vehicle lighting fixtures and light-emitting display bodies, and the like. The former is a front (sub-classification) headlamp, auxiliary light, vehicle width light, fog lamp, direction indicator light, etc., and the rear is a rear combination lamp as stop lamp, vehicle width light, back light, direction indicator light, and There are license plate lights. In particular, by forming a single rear combination lamp using an organic EL element and attaching it to the rear part, it is possible to reduce the space for the rear lamp and widen the trunk room. In addition, when the visibility is poor due to rain or fog, the visibility of the vehicle can be increased by widening the area of the vehicle width lights and stop lamps. On the other hand, the visibility from the side surface can be enhanced by causing the wheel to emit light with the organic EL element. Furthermore, the entire body can be made of organic EL elements to emit light, and new ideas can be incorporated into the body color and design.

  Examples of the latter in-vehicle lighting fixtures and light-emitting displays include indoor lights, map lights, boarding lights at the bottom of doors, meter displays, car navigation displays, warning lights, and the like. In particular, taking advantage of the transparency of the organic EL element, a sunroof can be used during the daytime and light can be emitted during the nighttime to provide a room light with a gentle surface light source. For taxis, etc., a lighting system consisting of organic EL elements is pasted on the back of the front seat, creating a handy lighting system that is easy for customers to use without hindering driver driving and sacrificing indoor space. Can be built.

〔Public transport〕
The characteristics of the organic EL of the present invention can be utilized in lighting and display bodies in vehicles in public transportation such as trains, subways, buses, airplanes, and ships.

  Many lighting fixtures are installed in aircraft, but the benefits of organic EL lighting are fully demonstrated, especially for cabin indirect lighting among cabin lighting, cargo cabin lighting, cockpit lighting, etc. that are mounted inside the aircraft. Is done.

  Fluorescent lamps and light bulbs are used for room lighting, but these use indirect lighting reflected on the ceiling and sides, giving the guest room a calm atmosphere and breaking glass in the event of a trouble. Has been devised so that does not fall into the audience seats.

  If an organic EL light source is used, it is easy to make indirect illumination because of its thinness, and even if it is directly illuminated, there is no risk of cracking and scattering of fragments, and it is possible to create a calm atmosphere with diffuse light.

  Moreover, even if it considers from the aspect that power consumption and weight reduction of an airframe are important for an aircraft, a light-weight organic EL light source with low power consumption is preferable. These benefits not only illuminate the customer, but are also demonstrated in the lighting inside the baggage storage, and can contribute to the reduction of leftovers.

  Display and lighting to guide customers can also be used at facilities such as stations, bus stops, and airports attached to public transportation. In addition, at night or at an outdoor bus stop, a person waiting for the bus can be detected to brighten the lighting, thereby contributing to crime prevention.

[Light source for OA equipment]
Examples of light sources for office automation equipment include facsimiles, copying machines, scanners, printers, and multi-function machines equipped with reading sensors.

  The reading sensor is divided into a contact type sensor (CIS) combined with an equal magnification optical system and a reduction type sensor (CCD linear) combined with a reduction optical system.

  The definition of CIS differs depending on the manufacturer. When the sensor, rod lens array, and LED base are modularized, the module is called CIS, or the modularized module is called CISM (contact image sensor module). The existing sensor chip may be called CIS. For these light sources, LEDs, xenon, CCFL lamps, LDs and the like are used.

  There is a demand for further miniaturization and low-voltage driving as an OA device, and the feature that the organic EL has no thickness and can be driven with a low calorific value and low voltage can meet these demands. .

[Industrial inspection system]
In the past, manufacturing companies used a lot of man-hours and manpower for the visual inspection process, but this is automated by using a photographed image to determine the shortage. The image of the object captured by the CCD camera is converted into a digital signal, and various arithmetic processes are performed to extract features such as the area, length, number, and position of the object. The one that outputs the result of the determination is that a light source is required to capture the image. Such an inspection system is also used for package, shape size inspection, micro component inspection, and the like.

  Illumination light sources used for image sensors include fluorescent lamps, LEDs, and halogens. Among them, a uniform light is required as a backlight to illuminate transparent containers and lead frames from the background.

  Further, the detection of the stain on the sheet requires a light source depending on the article to be inspected, such as light that illuminates the front surface in the width direction of the sheet with linearly uniform light.

  By adopting an organic EL light source in this field, for example, in the bottling process, it is possible to illuminate all 360 degrees around the bottle and illuminate and shoot at once, enabling inspection in a short time Become. Moreover, the space taken by the light source itself in the inspection equipment can be greatly reduced. Further, since the surface light source is used, it is possible to avoid a detection error due to difficulty in determining a captured image due to light reflection.

[Light source for agricultural products]
The plant factory is “an annual plant production system using high technology such as environmental control and automation”. A technology that automatically produces crops by controlling the plant cultivation environment with a computer, without being affected by the weather, and without the need for manpower. Considering the world's population growth and environmental issues in the future, the introduction of high technology to agriculture will require the so-called agricultural industrialization that leads to stable food production. Recently, LED and LD have been increasingly used as light sources for plant cultivation. Light sources such as high-pressure sodium lamps that have been widely used in the past have a poor spectral balance between red light and blue light, and a large amount of heat radiation increases the air conditioning load and requires a sufficient distance from the plant. There is a drawback that the facility becomes larger.

  Since the organic EL light source has no light source thickness, many shelves can be installed, and since the calorific value is small, it is highly efficient and can increase the amount of cultivation by being close to the plant.

  Also, taking advantage of space-saving in ordinary households, you can create a kitchen garden in a small indoor space such as a kitchen, changing the concept of a kitchen garden that was possible only in outdoor spaces such as gardens, verandas, and rooftops. It allows people to enjoy widely.

[Evacuation lighting]
Disaster prevention lighting equipment stipulated in the Fire Service Law and Building Standard Law is an emergency light that guarantees quick evacuation by ensuring the brightness of the evacuation route and the guide light that shows the exit and route for blame in case of building fire There is.

  Signals, guide lights, emergency lights, etc. used for FA / consumer use are premised on being easy to see, but the enlargement for that is unbalanced with the building depending on the installation location, and it is pointed out by architects and designers There were many things. As countermeasures, measures are taken to make the display a practicable graph that can be seen at a glance and to increase the attractive effect with a light source. Conventionally, a fluorescent lamp is often used as a light source of a guide lamp, but recently, a guide lamp using an LED has also come out.

  By using an organic EL light source for these guide lights, there is no reduction in brightness due to brightness spots and angular characteristics, visibility can be improved, and low power consumption and thinness make it easy to install without special work. Compared to conventional fluorescent lamp types, there is no need for replacement, and maintenance can be facilitated. In addition, since there is little heat generation, there is little color burn on the light emitting surface. Therefore, it can be installed in many places such as floors of evacuation routes, stairs handrails, fire doors, etc. to improve safety. In addition, there is no problem of mercury, which is currently regarded as a problem with fluorescent lamps, it is difficult to break, and it has excellent safety. Furthermore, it can be said that it is a light source that can enhance the attractive effect without impairing the beauty of the space-saving thin design.

[Lighting for shooting]
Halogen, tungsten, strobe light, fluorescent light, etc. are used as light sources used in photo studios, studios, and lighting photo boxes. Applying these light sources directly to the subject to add a strong shadow, or diffuse light to create soft light with little shadow, a combination of two types of light from various angles. Is made. In order to diffuse light, there are methods such as sandwiching a diffuser between a light source and a subject, or using reflected light applied to another surface (reflective plate or the like).

  The organic EL light source is diffused light, and light corresponding to the latter can be emitted without using a diffuser. In that case, the space between the light source and the diffuser required by the existing light source becomes unnecessary, and the light that has been adjusted with a fine angle by adjusting the direction of the light with a reflex plate etc. is flexible There is an advantage that it can be implemented by bending the type of organic EL itself.

  A color rendering property may be required for a light source used for photographing. If the difference in the color appearance when viewed with sunlight is large, the color rendering is poor, and if the difference is small, the color rendering is evaluated as good. Fluorescent lamps used in general households are not preferable for photographing because of their wavelength characteristics, and the portions that are exposed to light tend to be green. The color of skin, makeup, hair, kimono, jewelry, etc. is often required to be reflected in its own color, and color rendering is one of the important factors for light. An organic EL light source is excellent in color rendering, and is preferable for photographing that requires color fidelity as described above. This feature is also used in places where it is desired to faithfully evaluate colors such as printing and dyeing.

  By placing a surface light source, such as an organic EL light source, on the ceiling of the studio, children and pets can freely play indoors when shooting children and pets, etc., and free and natural expressions can be moved without the hassle of moving light sources Can shoot with natural colors.

〔Home appliances〕
Household appliances are often equipped with light sources for ease of viewing details, ease of work, and design. For example, sewing machines, microwave ovens, dishwashers / dryers, refrigerators, AV equipment, etc. have traditionally been equipped with light sources, but newer models have a light source because they are left behind in the horizontal model. It came to be able to. In many cases, incandescent bulbs and LEDs are attached to existing ones. In the future, we will install lighting at the tip of the vacuum cleaner to check the cleaning status of shadow parts such as furniture, install a light source of specific wavelength light on the shaver, and check the shaving status, etc. Development is possible.

  Such home appliances are required to be light and small as a whole and have a large storage space, and the light source part is required to be able to illuminate the whole without taking up as much space as possible. The thin surface light source of organic EL can fully meet the demand.

[Amusement facilities]
By arranging lighting using organic EL under the ice of the skating rink, it is possible to produce an effect different from the spotlight from above. Organic EL is particularly advantageous because of its low emission temperature. It is also possible to detect the position of the skater and emit light according to the movement of the skater. Combination effects with spotlights and light emission linked to the rhythm of music are also effective for show-ups.

  In the planetarium, instead of the conventional projection from the bottom, a system in which fine pixels of organic EL are arranged on the entire dome and the dome itself emits stars is possible, and a planetarium without a projector can be realized.

[Illumination lighting]
In general, the term “illumination” generally refers to illumination of trees, but in recent years there have been many cases of transition to decoration of objects such as houses, gates, and fences from the viewpoint of environmental protection. Yes. The mainstream of this is the use of a large number of point light sources, decorated in a line shape, and is expected to be even more widespread with the advent of LEDs.

  By using organic EL lighting in this field, what was previously expressed only by connecting point light sources, it is possible to use leaf-shaped lighting or wrap around trees for illumination of the same tree. Light up the whole tree, or conversely, connect it like a point light source as a standard surface module, and use it as a cocktail palette to shine in various colors to project characters and pictures as a whole, further enhancing the lighting effect by lighting It becomes possible.

[Lighting for belongings and clothes]
Reflective products that protect the safety of pedestrians by reflecting the light from the headlights attached to their belongings, shoes, and clothes for the purpose of making it easier to be recognized by cars and motorcycles during night walking and exercise. Sheet etc.) are sold and used.

  In the case of the glass bead type, fine glass beads are present on the surface, and the incoming light is retroreflected in the direction of the light source by the role of this lens. It seems to shine strongly when I return. The prism type also has the same function, but the lens structure is different. The glass bead type and the prism type feature that the glass bead type has a high reflection effect on light from an oblique direction, and the prism type reflects light from the front than the glass bead type, but from an oblique direction. The light may have a relatively low reflection effect. In addition, the material and the bonding method can be selected depending on the place to be attached. In any case, in order to make pedestrians aware of light, it is necessary to be exposed to light. It was necessary to devise such as pasting.

  By using an organic EL light source for these alternatives, the driver can be made to recognize the pedestrian before the headlight hits the area, and safety can be ensured. Further, from the point of being light and thin with respect to other light sources, the effect can be obtained while maintaining the merit of the seal. These can be used not only for humans but also for pet clothes. In addition, it is possible to generate electricity by walking to emit light from clothes, etc., with an organic EL with low power consumption. In particular, the present invention can be applied to clothes for identifying a person, and can be used for early protection of a deaf person, for example. By making the wet suit for diving emit light, there is a possibility of confirming the location of the diver and protecting himself from the trap. Of course, it can also be used for stage costumes and wedding dresses at shows.

[Communication light source]
Luminescent bodies using organic EL elements can be effectively used in “visible light tags” that send simple messages and information using visible light. That is, by emitting a signal due to blinking for an extremely short time, a large amount of information can be sent to the receiving side.

  Even if the illuminant emits a signal, since it is extremely short time, it is recognized as simple illumination in human vision. Lighting installed at each location, such as roads, stores, exhibition halls, hotels, and amusement parks, can send information signals specific to each location and provide necessary information to the receiver. In the case of organic EL, a single light emitter provides a plurality of different information by incorporating a plurality of light emitting dopants having different wavelengths into one light emitter and generating different signals for different wavelengths. You can also. Also in this case, the organic EL having a stable emission wavelength and color tone is superior.

  Unlike providing information by voice, radio waves, infrared light, etc., the “visible light tag” can be incorporated together as a lighting facility, so there is no need for complicated additional installation work.

[Medical light source]
The use of organic EL for endoscopes that currently use halogen lamps and illumination for abdominal surgery that operates with a wire inserted will contribute to miniaturization, weight reduction, and application expansion. In particular, it can be used for endoscope capsules (drinking endoscopes) that are attracting attention in recent years and are used for in-vivo examinations and treatments.

[Others]
Furthermore, since the light emitter incorporating the organic EL element of the present invention can easily select the color tone, does not flicker like a fluorescent lamp, and has a stable color tone with low power consumption, Japanese Patent Application Laid-Open No. 2001-269105 discloses. As a pest control apparatus as shown, as a mirror illumination as shown in JP-A-2001-286373, as a bathroom lighting system as shown in JP-A-2003-28895, as JP-A-2004-321074 As an artificial light source for plant growth shown in the official gazette, a photosensitizer as shown in Japanese Patent Application Laid-Open No. 2004-358063 was used as a light emitter of a water pollution measuring device as shown in Japanese Patent Application Laid-Open No. 2004-354232. As a treatment adherend, it is useful as a medical surgical light as disclosed in JP-A-2005-322602.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented. The structures of the compounds used below are shown together at the end of the examples.

  Note that the emission maximum wavelengths of BD-1 to BD-6 described below are all 480 nm or less, the emission maximum wavelength of GD-1 is in the range of 500 nm to less than 580 nm, and the emission maximum wavelength of RD-1 Was in the region of 580 nm or more.

Example 1
<< Production of organic EL element >>
[Production of Organic EL Element 1-1]
Transparent support with this ITO transparent electrode after patterning on a support substrate in which ITO (Indium Tin Oxide) is deposited to a thickness of 110 nm on a glass substrate of 30 mm × 30 mm and thickness 0.7 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, and then the transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus.

  Each of the deposition crucibles in the vacuum deposition apparatus was filled with the constituent material of each layer in an optimum amount for device fabrication. The evaporation crucible used was made of a resistance heating material made of molybdenum or tungsten.

Next, after reducing the pressure to 1 × 10 ⁻⁴ Pa, the current crucible for deposition containing m-MTDATA was energized and heated, deposited on a transparent support substrate at a deposition rate of 0.1 nm / second, A hole injection layer was provided. Next, α-NPD was deposited in the same manner to provide a 20 nm hole transport layer.

  Next, Compound BD-2 and Compound M-1 were co-evaporated at a deposition rate of 0.1 nm / second with 20% of Compound BD-2 to form a phosphorescent light-emitting layer having a thickness of 80 nm.

  Thereafter, Compound M-2 was deposited to a thickness of 30 nm to form an electron transport layer, and KF was further formed to a thickness of 2 nm. Furthermore, aluminum 110nm was vapor-deposited and the cathode was formed.

Subsequently, the non-light-emitting surface of the element was covered with a glass case, and an organic EL element having the configuration shown in FIGS. 1 and 2 was produced. (Comparison: uniform low concentration)
FIG. 1 is a schematic view of an organic EL element, and the organic EL element 101 is covered with a glass cover 102. The sealing operation with the glass cover was performed in a glove box (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more) in a nitrogen atmosphere without bringing the organic EL element 101 into contact with the atmosphere. FIG. 2 shows a cross-sectional view of the organic EL element. In FIG. 2, 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.

[Production of Organic EL Element 1-2]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Subsequently, it produced similarly except having made dope concentration of compound BD-2 into 22% (+ 10%).

[Production of Organic EL Element 1-3]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Subsequently, it produced similarly except having made dope concentration of compound BD-2 into 18% (-10%).

[Production of Organic EL Element 2-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

Subsequently, it produced similarly except having made the dope density | concentration of compound BD-2 60%. (Comparison: uniform high concentration)
[Production of Organic EL Element 2-2]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Subsequently, it produced similarly except having made the dope concentration of compound BD-2 into 66% (+ 10%).

[Production of Organic EL Element 2-3]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Subsequently, it produced similarly except having made the dope concentration of compound BD-2 54% (-10%).

[Production of Organic EL Element 3-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

Next, the compound BD-2 was deposited at a thickness of 20 nm while reducing the doping concentration of the compound BD-2 from 30% to 30% at a rate of -1.5% / nm, and then from 30% to 15%, -0.75% / nm. The film was formed in the same manner except that the light-emitting layer having a thickness of 40 nm was formed as a whole by depositing 20 nm while reducing the ratio. (Comparison: thin concentration gradient)
[Production of Organic EL Element 3-2]
It carried out similarly to the organic EL element 3-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of compound BD-2 starts from 66% (+ 10%) and is reduced to -30%, decreasing at a rate of -1.8% / nm to 20 nm, and thereafter from 30% to 15%, -0. It was produced in the same manner except that 20 nm was deposited while decreasing at a rate of 75% / nm.

[Production of Organic EL Element 3-3]
It carried out similarly to the organic EL element 3-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of Compound BD-2 was started from 54% (-10%) to 30% and decreased at a rate of -1.2% / nm to 20 nm, and thereafter from 30% to 15%, -0 It was produced in the same manner except that 20 nm was deposited while decreasing at a rate of .75% / nm.

[Production of Organic EL Element 4-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Next, the compound BD-2 was deposited at a thickness of 20 nm while reducing the doping concentration of the compound BD-2 from 30% to 30% at a rate of -1.5% / nm, and then from 30% to 15%, -0.25% / nm. The film was formed in the same manner except that the light emitting layer having a thickness of 80 nm was formed as a whole by vapor deposition of 60 nm while decreasing the ratio.

[Production of Organic EL Element 4-2]
It carried out similarly to the organic EL element 4-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of compound BD-2 starts from 66% (+ 10%) and is reduced to -30%, decreasing at a rate of -1.8% / nm to 20 nm, and thereafter from 30% to 15%, -0. It was fabricated in the same manner except that 60 nm was deposited while decreasing at a rate of 25% / nm.

[Production of Organic EL Element 4-3]
It carried out similarly to the organic EL element 4-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of Compound BD-2 was started from 54% (-10%) to 30% and decreased at a rate of -1.2% / nm to 20 nm, and thereafter from 30% to 15%, -0 It was produced in the same manner except that 60 nm was deposited while decreasing at a rate of 25% / nm.

[Production of Organic EL Element 5-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Next, the compound BD-2 was deposited at a thickness of 20 nm while reducing the doping concentration of the compound BD-2 from 30% to 30% at a rate of -1.5% / nm, and then from 30% to 15%, -0.15% / nm. This was prepared in the same manner except that the light emitting layer having a thickness of 120 nm was formed as a whole by depositing 100 nm while decreasing the ratio.

[Production of Organic EL Element 5-2]
It carried out similarly to the organic EL element 5-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of compound BD-2 starts from 66% (+ 10%) and is reduced to -30%, decreasing at a rate of -1.8% / nm to 20 nm, and thereafter from 30% to 15%, -0. Produced in the same manner except that 100 nm was deposited while decreasing at a rate of 15% / nm.

[Production of Organic EL Element 5-3]
It carried out similarly to the organic EL element 5-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of Compound BD-2 was started from 54% (-10%) to 30% and decreased at a rate of -1.2% / nm to 20 nm, and thereafter from 30% to 15%, -0 .Same production except that 100 nm was deposited while decreasing at a rate of 15% / nm.

[Production of Organic EL Element 6-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Next, the compound BD-2 was deposited at a thickness of 20 nm while starting the doping concentration of 40% starting from 40% and decreasing at a rate of -0.5% / nm from 30%, and then from 30% to 15%, -0.25% / nm. The film was formed in the same manner except that the light emitting layer having a thickness of 80 nm was formed as a whole by vapor deposition of 60 nm while reducing the ratio.

[Production of Organic EL Element 6-2]
It carried out similarly to the organic EL element 6-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of Compound BD-2 was started from 44% (+ 10%) and decreased to 30%, decreasing at a rate of −0.7% / nm, and then deposited to 20 nm, and thereafter from 30% to 15%, −0. Produced in the same manner except that 60 nm was deposited while decreasing at a rate of 25% / nm.

[Production of Organic EL Element 6-3]
It carried out similarly to the organic EL element 6-1, and provided to the positive hole transport layer.

  Subsequently, the doping concentration of Compound BD-2 was started from 36% (-10%) and decreased to 30%, decreasing at a rate of -0.3% / nm to 20 nm, and thereafter from 30% to 15%, -0 Prepared in the same manner except that 60 nm was deposited while decreasing at a rate of 25% / nm.

[Production of Organic EL Element 7-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Next, a 10% layer having a 100% doping concentration of Compound BD-2 was vapor-deposited to 10 nm, and then an 8% layer was vapor-deposited to 40 nm to form a light-emitting layer having a thickness of 50 nm as a whole.

[Production of Organic EL Element 7-2]
It carried out similarly to the organic EL element 7-1, and provided to the positive hole transport layer.

  Next, a 10% layer having a 100% doping concentration of Compound BD-2 was deposited, and then a 9% layer was deposited to 40 nm.

[Production of Organic EL Element 7-3]
It carried out similarly to the organic EL element 7-1, and provided to the positive hole transport layer.

  Next, a 10% layer having a 100% doping concentration of Compound BD-2 was vapor-deposited, and then a 7% layer was vapor-deposited to 40 nm.

[Production of Organic EL Element 8-1]
It carried out similarly to the organic EL element 1-1, and provided to the positive hole transport layer.

  Next, it was prepared in the same manner except that the deposition concentration of Compound BD-2 started from 100% and decreased to 8% at a rate of -2.3% / nm while depositing 40 nm.

[Production of Organic EL Element 8-2]
It carried out similarly to the organic EL element 8-1, and provided to the positive hole transport layer.

  Next, it was prepared in the same manner except that the deposition concentration of Compound BD-2 was started from 90% and decreased to 8% at a rate of -2.05% / nm while depositing 40 nm.

[Production of Organic EL Element 8-3]
It carried out similarly to the organic EL element 6-1, and provided to the positive hole transport layer.

  Next, it was prepared in the same manner except that the deposition concentration of compound BD-2 was started from 80% and decreased to 8% at a rate of -1.8% / nm while depositing 40 nm.

  The following evaluation was performed about the produced organic EL element.

<< Evaluation of organic EL elements >>
(Measurement of 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. In the table, the relative value when the power efficiency of the organic EL element 1 is 100 is shown.

[Measurement of drive life]
The luminance fluctuation during continuous driving was measured with the front luminance of 3000 cd / m ² as the initial luminance, and the luminance half time was determined as the driving life. In the table, the organic EL element 1 is displayed as a relative value when the driving life is 100.

[Measurement of chromaticity fluctuation range]
Chromaticity variation range was determined front luminance 300cd ^{/ m 2} ~1500cd ^/ m 2 in the CIE 1931, x, the maximum distance ΔE fluctuation of y-value in the following formula.

ΔE = (Δx ² + Δy ² ) ^1/2

  The “Δ efficiency” refers to the difference in efficiency between the three parties with different dope concentrations.

  As shown in Table 1, the organic EL device having the device configuration of the present invention has a wide concentration latitude of the blue phosphorescent compound (BD) in the light emitting layer, good production stability, and high practicality. In terms of power efficiency and lifetime, both have been improved.

Example 2
<< Production of organic EL element >>
[Production of Organic EL Elements 9-1, 9-2, 9-3]
The organic EL elements 9-1, 9-2, 9- are the same as the organic EL elements 4-1, 4-2, 4-3 except that the material used for the light emitting layer is changed to BD-3 instead of BD-2. 3 was produced.

[Production of Organic EL Elements 10-1, 10-2, 10-3]
The organic EL elements 10-1, 10-2, 10- are the same as the organic EL elements 4-1, 4-2, 4-3 except that the material used for the light emitting layer is BD-4 instead of BD-2. 3 was produced.

[Production of Organic EL Elements 11-1, 11-2, 11-3]
The organic EL elements 11-1, 11-2, 11- are the same as the organic EL elements 4-1, 4-2, 4-3 except that the material used for the light emitting layer is changed to BD-5 instead of BD-2. 3 was produced.

[Production of Organic EL Elements 12-1, 12-2, 12-3]
The organic EL elements 12-1, 12-2, 12- are the same as the organic EL elements 4-1, 4-2, 4-3 except that the material used for the light emitting layer is changed to BD-6 instead of BD-2. 3 was produced.

[Production of Organic EL Elements 13-1, 13-2, and 13-3]
The organic EL elements 13-1, 13-2, 13- are the same as the organic EL elements 4-1, 4-2, 4-3 except that the material used for the light emitting layer is BD-1 instead of BD-2. 3 was produced. (Comparison)
The result of having performed evaluation similar to Example 1 is shown.

  “ΔEfficiency” is the difference in efficiency between the three parties changing the doping concentration.

  As shown in Table 2, the blue phosphorescent compound having the molecular structure of the present invention has a wide concentration latitude of the blue phosphorescent compound (BD) in the light emitting layer, good production stability, and high practicality. In addition, both power efficiency and lifetime are improved.

Example 3
[Preparation of transparent conductor B-1]
SWCNT: P3 swcnt product supplied by Carbon Solutions was used on a 100 μm thick polyethylene terephthalate film support with a gas barrier layer on both sides, using a spin coater so that the target amount was 30 mg / m ^2. It was applied and dried to produce a transparent conductor B-1, which was patterned by plasma etching. Next, the following conductive polymer liquid P-1 was attached to a gravure coating machine K printing proofer (manufactured by Matsuo Sangyo Co., Ltd.) with a plate on which a square tile pattern with a printed pattern side length of 20 mm and a pattern interval of 10 mm was formed, and applied with CNT Gravure printing was performed by adjusting the number of printings so that the dry film thickness was 150 nm on the layer to form a square tile-shaped conductive polymer layer pattern, which was heated at 110 ° C. for 30 minutes.

[Preparation of transparent conductor B-2]
As metal fibers, Adv. Mater. , 2002, 14, 833 to 837, a silver nanowire having an average minor axis of 75 nm and an average length of 35 μm is produced using polyvinylpyrrolidone K30 (molecular weight: 50,000; manufactured by ISP). After silver nanowires are filtered and washed with an outer filtration membrane, the dispersion is redispersed in an aqueous solution in which 25% by mass of hydroxypropylmethylcellulose 60SH-50 (manufactured by Shin-Etsu Chemical Co., Ltd .; hydroxyl value 700 mg / g) is added to silver. A silver nanowire dispersion liquid (AG-1) was prepared. The silver nanowire dispersion was applied to a 100 μm thick polyethylene terephthalate film support having gas barrier layers on both sides so that the amount of silver nanowires was 50 mg / m ^2. Applied and dried. Subsequently, the silver nanowire coating layer was calendered to produce a transparent conductor B-2.

  A plate in which a square tile pattern having a printed pattern side length of 20 mm and a pattern interval of 10 mm is formed on a gravure coating machine K printing proofer (manufactured by Matsuo Sangyo Co., Ltd.) using a conductive polymer liquid P-1 prepared by the following method. Attach, gravure printing was performed by adjusting the number of times of printing so that the dry film thickness was 300 nm on the silver nanowire coating layer, and a square tile-shaped conductive polymer layer pattern was formed and heated at 110 ° C. for 30 minutes. Furthermore, the silver nanowire coating layer of the obtained film without the conductive polymer layer was immersed in a silver etching solution BF-1 prepared by the following method for 10 seconds, and further an ultrasonic cleaner US-10PS (SND). The product was removed by ultrasonic cleaning in water for 10 minutes, and then washed with water and dried to produce a transparent conductive film TCF-1.

<Preparation of silver etching solution BF-1>
Ethylenediaminetetraacetic acid ferric ammonium 60g
Ethylenediaminetetraacetic acid 2g
Sodium metabisulfite 15g
70g ammonium thiosulfate
Maleic acid 5g
Finished to 1 L with pure water, adjusted pH to 5.5 with sulfuric acid or ammonia water, and prepared silver etching solution BF-1.

(Preparation of conductive polymer liquid P-1)
(Synthesis of poly (2-hydroxyethyl acrylate))
2-Bromoisobutyryl bromide (7.3 g, 35 mmol), triethylamine (2.48 g, 35 mmol) and THF (20 ml) were added to a 50 ml three-necked flask, and the internal temperature was kept at 0 ° C. with an ice bath. In this solution, 30 ml of 33% THF solution of oligoethylene glycol (10 g, 23 mmol, ethylene glycol units 7-8, manufactured by Laporte Specialties) was added dropwise. After stirring for 30 minutes, the solution was brought to room temperature and further stirred for 4 hours. After THF was removed under reduced pressure by a rotary evaporator, the residue was dissolved in diethyl ether and transferred to a minute funnel. Water was added and the ether layer was washed three times, and then the ether layer was dried with MgSO ₄ . The ether was distilled off under reduced pressure using a rotary evaporator to obtain 8.2 g (yield 73%) of initiator 1.

  Initiator 1 (500 mg, 1.02 mmol), 2-hydroxyethyl acrylate (4.64 g, 40 mmol, manufactured by Tokyo Chemical Industry Co., Ltd.), 50 ml of 50:50 v / v% methanol / water mixed solvent was put into a Schlenk tube, and the pressure was reduced. The Schlenk tube was immersed in liquid nitrogen for 10 minutes. The Schlenk tube was taken out of liquid nitrogen and replaced with nitrogen after 5 minutes. After performing this operation three times, bipyridine (400 mg, 2.56 mmol) and CuBr (147 mg, 1.02 mmol) were added under nitrogen, and the mixture was stirred at 20 ° C. After 30 minutes, the reaction solution was dropped onto a 4 cm Kiriyama funnel with filter paper and silica, and the reaction solution was recovered under reduced pressure. The solvent was distilled off under reduced pressure using a rotary evaporator and then dried under reduced pressure at 50 ° C. for 3 hours. As a result, 2.60 g (yield 84%) of water-soluble binder resin 1 having a number average molecular weight of 13,100, a molecular weight distribution of 1.17, and a content of number average molecular weight <1000 of 0% was obtained.

  The structure and molecular weight were measured by 1H-NMR (400 MHz, manufactured by JEOL Ltd.) and GPC (Waters 2695, manufactured by Waters), respectively.

<GPC measurement conditions>
Apparatus: Wagers 2695 (Separations Module)
Detector: Waters 2414 (Refractive Index Detector)
Column: Shodex Asahipak GF-7M HQ
Eluent: Dimethylformamide (20 mM LiBr)
Flow rate: 1.0 ml / min
Temperature: 40 ° C
The obtained water-soluble binder resin 1 was dissolved in pure water to prepare a water-soluble binder resin 1 aqueous solution having a solid content of 50%.

  Next, a conductive polymer liquid P-1 was prepared as follows.

(Conductive polymer liquid P-1)
Water-soluble binder resin 1 aqueous solution (solid content 50% aqueous solution) 0.14 g
PEDOT-PSS CLEVIOS PH510 (solid content 1.89%) (manufactured by HC Starck) 1.59 g
<< Production of organic EL element >>
[Production of Organic EL Elements 14-1, 14-2, 14-3]
The support and transparent conductor used in Examples 1 and 2 were changed from glass + ITO to B-1 and then reduced in vacuum to 1 × 10 ⁻⁴ Pa, and then directly without vapor deposition of m-MTDATA. The organic EL element 14-1 was the same as the organic EL elements 3-1, 3-2 and 3-3 except that α-NPD was deposited at a deposition rate of 0.1 nm / second and a 70 nm hole transport layer was provided. 14-2 and 14-3. (Comparison)
[Production of Organic EL Elements 15-1, 15-2, 15-3]
The support and the transparent conductor were changed from glass + ITO to B-1, and then the pressure was reduced to a vacuum of 1 × 10 ⁻⁴ Pa. Organic EL elements 15-1, 15-2, and 15-3 are the same as organic EL elements 1-1, 1-2, and 1-3 except that α-NPD is deposited and a 70 nm hole transport layer is provided. Was made.

[Production of Organic EL Elements 16-1, 16-2, 16-3]
The support and the transparent conductor were changed from glass + ITO to B-1, and then the pressure was reduced to a vacuum of 1 × 10 ⁻⁴ Pa, and then directly without vapor deposition of m-MTDATA at a deposition rate of 0.1 nm / second. Organic EL elements 16-1, 16-2, 16-3 are the same as the organic EL elements 4-1, 4-2, 4-3 except that α-NPD is deposited and a 70 nm hole transport layer is provided. Was made.

[Production of Organic EL Elements 17-1, 17-2, 17-3]
The support and the transparent conductor were changed from glass + ITO to B-2, and then the pressure was reduced to a vacuum of 1 × 10 ⁻⁴ Pa, and then the deposition rate was 0.1 nm / second directly without depositing m-MTDATA. The organic EL elements 17-1, 17-2, 17-3 are the same as the organic EL elements 3-1, 3-2, and 3-3 except that α-NPD is deposited and a 70 nm hole transport layer is provided. Was made. (Comparison)
[Production of Organic EL Elements 18-1, 18-2, 18-3]
The support and the transparent conductor were changed from glass + ITO to B-2, and then the pressure was reduced to a vacuum of 1 × 10 ⁻⁴ Pa, and then the deposition rate was 0.1 nm / second directly without depositing m-MTDATA. Organic EL elements 18-1, 18-2, 18-3 are the same as the organic EL elements 1-1, 1-2, 1-3 except that α-NPD is deposited and a 70 nm hole transport layer is provided. Was made. (Comparison)
[Production of Organic EL Elements 19-1, 19-2, 19-3]
The support and the transparent conductor were changed from glass + ITO to B-2, and then the pressure was reduced to a vacuum of 1 × 10 ⁻⁴ Pa, and then the deposition rate was 0.1 nm / second directly without depositing m-MTDATA. Organic EL elements 19-1, 19-2, 19-3 were the same as the organic EL elements 4-1, 4-2, 4-3 except that α-NPD was deposited and a 70 nm hole transport layer was provided. Was made.

  In the above, “Δ efficiency” is the difference in efficiency between the three parties changing the doping concentration.

  As shown in Table 3, in the element configuration of the present invention, the performance is greatly improved over the known element configuration in combination with CNT and Ag nanowire (AgNW) which are expected as an ITO alternative transparent conductive film.

Example 4
Similarly to the organic EL element 16-1 of Example 3, the hole transport layer was provided on the base material and the transparent conductive film of B-2 of Example 3.

  Next, Compound BD-2, Compound RD-1, Compound GD-1 and Compound M-1 were combined with Compound BD-2 in the same manner as the organic EL device 3-1, and Compounds RD-1 and GD-1 had front chromaticity. Are co-evaporated at a deposition rate of 0.1 nm / second at optimum concentrations so that x becomes 0.45 ± 0.03 and y = 0.42 ± 0.03 (CIE1931), and phosphorescence with a thickness of 40 nm is obtained. An element 20-1 was produced in the same manner as in Example 17-1, except that the light emitting layer was formed.

  The organic EL elements 20-2 and 20-3 were produced by changing only the amount of BD from 20-1 to ± 10%.

  In the same manner as above, the compound RD-1 and GD of Example 3 19-1 also had a front chromaticity of x = 0.45 ± 0.03 and y = 0.42 ± 0.03 (CIE 1931). -1 was co-deposited at an optimum concentration at a deposition rate of 0.1 nm / second to form a phosphorescent light-emitting layer having a thickness of 80 nm, thereby producing an element 21-1. Only the amount of BD from this element 21-1 was changed to ± 10%, and elements 21-1 to 21-3 were produced.

  In the following, “Δefficiency” is the difference in efficiency between the three parties changing the doping concentration. In addition, “ΔE” is white, “elements 18-1 and 19-1 having a reference dope amount matched to white“ front chromaticity x = 0.45 ± 0.03, y = 0.42 ± 0.03 (CIE1931) ”. 3 shows the maximum light emission chromaticity difference between the three when a device in which only the amount on the anode side of BD is changed by ± 10% is produced and light is emitted at 1000 cd.

  As shown in Table 4, the white phosphorescent organic EL device having the device configuration of the present invention not only has power efficiency and a high relative lifetime, but also has a very high performance in view of variations in the amount of BD added, particularly color variation. It is good and can greatly improve performance from the viewpoint of practicality of an organic EL element used for white illumination.

  The structure of the compound used above is shown below.

DESCRIPTION OF SYMBOLS 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (8)

In an organic electroluminescence device having a pair of electrodes consisting of at least an anode and a cathode and a light emitting layer disposed between the electrodes,
The light emitting layer contains (A) at least one phosphorescent dopant having a light emission λmax of 300 to 480 nm,
(B) The dopant has at least one partial structure selected from the following general formulas (A) to (D),
(C) The light emitting layer contains at least a host compound and the phosphorescent light emitting dopant, and the concentration of the phosphorescent light emitting dopant in the light emitting layer is not constant in the film thickness direction,
(D) The organic electroluminescent element characterized by the film thickness of this light emitting layer being 70 nm or more.

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]

[Wherein, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb, Rc, Rb1, and Rc1 each represents a hydrogen atom or a substituent, and A1 represents an aromatic ring or an aromatic heterocyclic ring. Represents the residues necessary to form and M represents Ir or Pt. ]

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]

[In the formula, Ra represents a hydrogen atom, an aliphatic group, an aromatic group or a heterocyclic group, Rb and Rc each represent a hydrogen atom or a substituent, and A1 forms an aromatic ring or an aromatic heterocyclic ring. And M represents Ir or Pt. ]   2. The organic electroluminescence device according to claim 1, wherein a concentration of the phosphorescent dopant in the light emitting layer is high at an anode side interface.   3. The organic electro of claim 1, wherein an average concentration of the phosphorescent dopant in a portion excluding a 20 nm portion in thickness from the anode side interface of the light emitting layer is 5 to 30 mass%. Luminescence element.   The organic electroluminescence device according to any one of claims 1 to 3, wherein the phosphorescent dopant has a highest electron occupation level shallower than 5.3 eV.   5. The organic electroluminescence device according to claim 1, wherein the highest electron occupation level of the host compound of the light emitting layer is 0.2 eV or more deeper than the phosphorescent light emitting dopant.   The organic color according to any one of claims 1 to 5, wherein the emission color is 0.1 or less in y value deviation from the black body radiation at each color temperature defined in the CIE1931 color system. Electroluminescence element.   The organic electroluminescent element according to claim 1, wherein at least one of the electrodes is a transparent electrode containing silver nanoparticles or silver nanowires.   The organic electroluminescence device according to any one of claims 1 to 7, wherein at least one of the electrodes is a transparent electrode containing carbon nanotubes having an outer diameter of less than 3.5 nm.

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