JP4853010B2 - Organic electroluminescence device and organic electroluminescence display - Google Patents

Description

  The present invention relates to an organic electroluminescence element and an organic electroluminescence display.

  As a light-emitting electronic display device, there is an electroluminescence display (ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements (inorganic EL elements) and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  An organic electroluminescence element has a structure in which a light emitting layer containing a compound that emits light is sandwiched between a cathode and an anode, and injects electrons and holes into the light emitting layer to recombine excitons. This is an element that emits light by utilizing the emission of light (fluorescence / phosphorescence) when this exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, 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 and portability.

  In order to further improve these advantages, there is a method comprising an electron blocking layer, a hole blocking layer, and a carrier transport layer containing a carrier donor or acceptor as means for increasing the exciton generation efficiency and lowering the driving voltage. It has been proposed (see Patent Document 1). However, these are only monochromatic examples, whitening is not described, and the use of phosphorescence with higher luminous efficiency is not suggested, and the level of driving voltage is still insufficient. Met.

  Further, a non-light emitting layer having base HOMO than the light emitting layer is provided on the anode side of the light emitting layer, and a non light emitting layer having a noble LUMO than the light emitting layer is provided on the cathode side of the light emitting layer, thereby Has been proposed (see Patent Document 2). However, this does not necessarily increase the exciton generation efficiency, and the movement of carriers between both poles has been proposed. The amount is only increased, and conversely, the luminous efficiency is often lowered.

Therefore, development of an organic EL element that emits light efficiently and with high luminance with lower power consumption is desired for organic EL elements for practical use in the future.
JP 2000-196140 A JP 2005-510025 A

  Accordingly, an object of the present invention is to obtain a white light-emitting organic EL element that emits light efficiently and with high luminance with low power consumption.

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

1. A supporting substrate has at least an anode, a cathode, and a plurality of light emitting layers that emit phosphorescence between the anode and the cathode, the plurality of light emitting layers have at least three phosphorescent dopants, and the resulting light is white. In an organic electroluminescence device, at least one light emitting layer is formed from the anode side, a hole transport layer containing an electron acceptor, an electron blocking layer containing an electron acceptor, a light emitting layer, and a hole blocking layer containing an electron donor. An organic electrolayer which is laminated in the order of an electron transport layer containing an electron donor and which constitutes each layer is composed of a material satisfying the following formulas (1-1) to (2-3). Luminescence element.
(1-1) Ea ^{A / HTL} > Ea ^HTL
(1-2) Ea ^{A / EBL} > Ea ^EBL
(1-3) Ea ^EM > Ea ^EBL
(2-1) Ip ^{D / ETL} <Ip ^ETL
(2-2) Ip ^{D / HBL} <Ip ^HBL
(2-3) Ip ^EM <Ip ^HBL
However, each term in the above formula represents the electron affinity and Ip represents the ionization potential in the material forming each layer. In addition, the values of the respective terms all represent absolute values, HTL is a material for forming a hole transport layer, ETL is a material for forming an electron transport layer, A / HTL is an electron acceptor in the hole transport layer, A / EBL is an electron acceptor in the electron blocking layer, D / HBL is an electron donor in the hole blocking layer, D / ETL is an electron donor in the electron transport layer, HBL is a material forming the hole blocking layer, EBL is an electron The material for forming the blocking layer, EM, indicates the respective values in the host compound in the light emitting layer.

  2. 2. The organic electroluminescence device according to 1 above, wherein materials other than at least the acceptor of the hole transport layer containing the electron acceptor and the electron blocking layer containing the electron acceptor are different.

  3. 3. The organic electroluminescence device according to 1 or 2 above, wherein materials other than at least the donor of the electron transport layer containing the electron donor and the hole blocking layer containing the electron donor are different.

  4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein at least one light emitting layer is adjacent to the electron blocking layer and the hole blocking layer.

  5. The electron transport layer containing the electron acceptor and the electron blocking layer are adjacent to each other, or the electron transport layer containing the electron donor and the hole blocking layer are adjacent to each other. The organic electroluminescent element of any one of Claims.

  6). 6. The organic electroluminescent device according to any one of 1 to 5, wherein at least 80% by mass or more of all materials contained in each layer constituting the device has a glass transition temperature (Tg) of 100 ° C. or higher. An organic electroluminescence element characterized by the above.

  7). The organic light-emitting device according to any one of 1 to 6, wherein the plurality of light-emitting layers include light-emitting layers of three colors of red, green, and blue.

8 . Different light-emitting layers in closest proximity respectively to the anode and the cathode, the thickness including the light emitting layer, the 7 SL placement of the organic electroluminescent device characterized in that it is a 5 to 30 nm.

9 . 9. An organic electroluminescence display using the organic electroluminescence element according to 7 or 8, wherein light emitted from the organic electroluminescence element is white light, and the white light is passed through a blue filter, a green filter, and a red filter. Te, blue light, green light, organic electroluminescence display you characterized in that to obtain a red light.

  The first object of the present invention is to provide an organic electroluminescence device capable of extracting white light with low power, high luminance and excellent color balance, and to provide an organic electroluminescence display using the device. The second object of the present invention is to provide a white backlight that realizes a display excellent in color reproducibility in combination with a color filter.

  Hereinafter, details of each component according to the present invention will be sequentially described.

《Organic electroluminescence device》
The organic electroluminescence element of the present invention will be described.

  The organic electroluminescence device of the present invention includes a plurality of light emitting layers, a hole transport layer, and an electron blocking layer including at least an anode, a cathode, and at least one light emitting layer emitting phosphorescence between the anode and the cathode on a substrate. , A hole blocking layer, and a layer including an electron transport layer.

  In the organic electroluminescence device according to the present invention, preferably, each light emitting layer is selected so that the plurality of light emitting layers constitute white, and more preferably, the plurality of light emitting layers are red, green, and blue, respectively. The light emitting layer of these three colors, which emits white light. Usually, the emission color is classified as blue light emission having a light emission maximum wavelength in the range of 430 nm to 480 nm, green light emission in the range of 510 nm to 550 nm, and red light emission in the range of 600 nm to 640 nm.

《Light emission, front luminance, chromaticity of organic electroluminescence device》
The emission color of the organic electroluminescence device of the present invention and the compound related to the device is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (Edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with the total CS-1000 (manufactured by Konica Minolta Sensing) is applied to the CIE chromaticity coordinates. The white color in the organic electroluminescence device of the present invention means that the chromaticity of the CIE1931 color system is x = 0.33 ± 0.07, y = 0.33 when the 2 ° C. viewing angle front luminance is measured by the above method. It is characterized by being in the range of ± 0.07.

<< Light extraction and / or condensing sheet >>
In particular, for organic electroluminescence devices for backlights, it is usually desirable that the light is radiated in all directions and the brightness does not change even if the viewing angle changes. It is desirable to reduce the luminance at a large viewing angle (an angle observed from an oblique direction). Therefore, it is preferable that a diffusion plate, a prism sheet and the like for controlling the radiation angle are combined on the organic electroluminescence element.

  Usually, in an organic electroluminescence device that emits light from a substrate (glass substrate, resin substrate, etc.), part of the light emitted from the light emitting layer causes total reflection at the interface between the substrate and air, and the light is emitted. The problem of loss occurs. In order to solve this problem, the prism surface or lens sheet is processed on the surface of the substrate, or the prism sheet or lens sheet is attached to the surface of the substrate, thereby suppressing total reflection and improving the light extraction efficiency. .

  Although the preferable form of a light extraction and / or condensing sheet | seat is demonstrated below, if it is in the range which does not impair the objective effect in this invention, light extraction efficiency can be improved using these.

(1) Configuration in which a diffusing plate and a prism sheet are placed on a glass substrate For example, in an organic electroluminescence device comprising a glass substrate / transparent conductive film / organic light emitting layer / electrode / sealing layer, it is opposite to the light emitting layer of the glass substrate The first diffusion plate is placed in contact with the substrate surface on the side. A first lens sheet (for example, 3M BEF II) is arranged so as to be in contact with the diffusion plate so that the lens surface faces the opposite side of the glass substrate, and the second lens sheet is formed with a stripe of the first lens. It is arranged so as to be orthogonal to the stripe of the lens and the lens surface thereof facing away from the glass substrate. Next, a second diffusion plate is disposed so as to be in contact with the second lens sheet. As the shape of the first and second lens sheets, a Δ-shaped stripe having an apex angle of 90 degrees and a pitch of 50 μm is formed of acrylic resin on a PET base material. A shape with a rounded apex angle (3M RBEF), a shape with a randomly changed pitch (3M BEF III), or other similar shapes may be used. As the first diffusion plate, a film in which beads for diffusing light are mixed is formed on a PET substrate of about 100 μm, and the transmittance is about 85% and the haze value is about 75%. As the second diffusion plate, a film in which beads for diffusing light are mixed is formed on a PET substrate of about 100 μm, and the transmittance is about 90% and the haze value is about 30%. The diffusion plate arranged in contact with the glass substrate may be bonded to the glass substrate via an optical adhesive. Further, a layer for diffusing light may be directly applied to the surface of the glass substrate, or a fine structure for diffusing light may be provided on the surface of the glass substrate. The glass substrate has been described above, but the substrate may be a resin substrate.

(2) When forming a microlens array on the surface of a substrate In an organic electroluminescence device comprising a glass substrate / transparent conductive film / organic light emitting layer / electrode / sealing layer, the surface of the glass substrate provided with the organic light emitting layer; Attach a microlens array sheet to the opposite surface via an optical adhesive. Each microlens array sheet has a shape in which microlenses each having a square apex of 50 μm (pyramid shape) and an apex angle of 90 degrees are aligned at a pitch of 50 μm. The sheet is manufactured by injecting UV curable resin between a metal mold that is the mother mold of the microlens array and a glass plate placed between 0.5 mm spacers, and UV exposure from the glass substrate. By doing so, the resin is cured to obtain a microlens array sheet. Here, as the shape of each microlens, a conical shape, a triangular pyramid shape, a convex lens shape, or the like is applicable. Although described as a structure in which the microlens array sheet is attached to the glass substrate, the microlens array sheet may be attached to the resin substrate. Moreover, the structure of providing a transparent electrode / organic light emitting layer / electrode / sealing layer on the surface opposite to the surface provided with the microlens array of the microlens array sheet may be used.

(3) Structure for adhering the microlens array sheet downward on the surface of the substrate In an organic electroluminescence device comprising a glass substrate / transparent conductive film / organic light emitting layer / electrode / sealing layer, an organic light emitting layer of the glass substrate is provided. The microlens array sheet is attached to the surface opposite to the surface on which the concave and convex surfaces of the microlens face the glass substrate side via an optical adhesive. The microlens array sheet has a shape in which microlenses having a structure in which the apexes of a rectangular shape each having a side of 50 μm are flat are arranged at a pitch of 50 μm. The flat top portion is adhered to the surface of the glass substrate. Here, as the shape of each microlens, a conical shape, a triangular pyramid shape, a convex lens shape, or the like is applicable. Although described as a structure in which the microlens array sheet is attached to the glass substrate, the microlens array sheet may be attached to the resin substrate.

  In order to further increase the light extraction efficiency, it is preferable to insert a low refractive index layer between the transparent electrode and the transparent substrate. 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 longer than the wavelength in the light medium, preferably twice or more. 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. Examples of the low refractive index layer of the present invention will be described below, but the present invention is not limited to these as long as the object effects are not impaired.

(1) Dispersion of hollow silica A method for producing a glass substrate in which a hollow silica is dispersed by a sol-gel method to form a low refractive index layer will be described. A low refractive index layer can be formed on a glass substrate by the following procedure. Metal alkoxide (tetraethyl silicate Si (OC ₂ H ₅ ) ₄ [abbreviated TEOS]) as a raw material compound, ethanol as a solvent, acetic acid as a catalyst, and water necessary for hydrolysis are added to a preparation liquid having a low refractive index. A material (catalyst chemical industry, silica particles (refractive index: 1.35)) added to isopropyl alcohol is mixed, and kept at several tens of degrees C to cause hydrolysis and polycondensation reaction to produce a liquid sol. . When the prepared sol is applied on a glass substrate by spin coating and reacted, it is solidified as a gel. This is further dried in an atmosphere of 150 ° C. to obtain a dry gel, and the conditions of the solution preparation and spin coating are set so that the film thickness at that time becomes 0.5 μm. As a result, a low refractive index layer having a thickness of 0.5 μm and a refractive index of 1.37 is formed. Here, spin coating is described as the solution coating method, but any method that can obtain a uniform film thickness may be used, such as dip coating. Although an example of a glass substrate is shown as the substrate, since the process temperature is 150 ° C. or less, it can be applied directly on the resin substrate. Further effects can be expected by selecting a lower refractive index as a raw material compound or a low refractive index material, and setting the refractive index of the resulting low refractive index layer to 1.37 or less. The film thickness is preferably 0.5 μm or more, more preferably 1 μm or more.

  Production of hollow silica is described in, for example, Japanese Patent Application Laid-Open Nos. 2001-167637, 2001-233611, and 2002-79616.

(2) In the case of silica airgel The transparent low refractive index layer is formed of silica airgel obtained by supercritical drying of a wet gel formed by a sol-gel reaction of silicon alkoxide. Silica airgel is a light-transmitting porous body having a uniform ultrafine structure. Liquid A was prepared by mixing tetramethoxysilane oligomer and methanol, and liquid B was prepared by mixing water, aqueous ammonia and methanol. An alkoxysilane solution obtained by mixing the A liquid and the B liquid is applied onto the substrate 2. After the alkoxysilane is gelled, it is immersed in a curing solution of water, aqueous ammonia, and methanol and cured at room temperature for one day. Next, the cured gel-like compound is immersed in an isopropanol solution of hexamethyldisilazane, hydrophobized, and then subjected to supercritical drying to form a silica airgel.

(3) In the case of porous silica As a low refractive index material, a film of a low relative dielectric constant material containing hexamethyldisiloxane or hexamethyldisilazane having water repellency is applied on a substrate to form a film. In addition to a water-repellent material such as hexamethyldisiloxane or hexamethyldisilazane, alcohol or butyl acetate may be added as an additive to the solution of the low relative dielectric constant material used here. . Then, a low refractive index film made of a porous silica material is formed by evaporating the solvent, water, acid, alkali catalyst, surfactant, or the like in the solution of the low relative dielectric constant material by firing treatment or the like. This is washed to obtain a low refractive index film.

After forming the low refractive index film on the substrate in this way, an intermediate layer is formed on the low refractive index film directly or with a transparent insulating film made of a SiO ₂ film by, for example, RF sputtering, and then the intermediate layer is formed. An ITO film is formed on the layer by DC sputtering to form a substrate with a transparent electrode.

  Further, in order to further increase the light extraction efficiency, for example, as described in Japanese Patent Application Laid-Open No. 11-283951, Japanese Patent Application No. 2005-48686, etc., diffraction occurs in the interface or any medium that causes total reflection. It is preferable to use a method of introducing a lattice together. For example, a diffraction grating is formed on a glass substrate.

  This method is generated from the light emitting layer by utilizing 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. Of the light, light that cannot go out due to total reflection between layers, etc., is diffracted by introducing a diffraction grating in any layer or medium (in the transparent substrate or transparent electrode) It tries to take out light. 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. As described above, 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 in the medium of the light to be amplified. The arrangement of the diffraction gratings is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

  For example, in order to form a diffraction grating on a glass substrate, a positive resist is applied to the surface after cleaning the glass substrate. Next, two parallel lights having a wavelength λ that are coherent with each other are irradiated on the resist so as to face each other at an angle of θ degrees from the vertical direction of the substrate. At this time, interference fringes having a pitch d are formed in the resist. Here, d = λ / (2 cos θ). When an argon laser having a wavelength of 488 nm is used and a 300 nm pitch is formed as a photonic crystal, if both light beams are exposed at an angle of 35.6 degrees from a direction perpendicular to the substrate, a first interference fringe having a pitch of 300 nm is formed. Is done. Next, the substrate is rotated 90 degrees in the plane of the substrate to form a second interference fringe so as to be orthogonal to the first interference fringe. If the light beam to be exposed is maintained as it is, second interference fringes are formed at a pitch of 300 nm. Two interference fringes are superimposed on the resist and exposed to form a grid-like exposure pattern. By appropriately setting the exposure power and the development conditions, the development is performed so that the resist is removed only at the portion where the two interference fringes overlap and is strongly exposed. On the glass substrate, a pattern in which the resist is removed in a substantially circular shape is formed in the overlapping portion of the lattices each having a vertical and horizontal pitch of 300 nm. The diameter of the circle is, for example, 220 nm. Next, dry etching is performed to form a hole having a depth of 200 nm in the portion where the range is removed. Thereafter, the resist is removed and the glass substrate is washed. As described above, a glass substrate in which holes having a depth of 200 nm and a diameter of 220 nm are arranged on the apexes of a square lattice having a pitch of 300 nm in length and width is formed on the surface. Next, an ITO film having a thickness of about 300 nm as measured from the bottom of the hole is formed by bias sputtering, and the surface unevenness can be flattened to 50 nm or less by appropriately controlling the bias sputtering conditions. By polishing the surface of the glass substrate with ITO prepared as described above, a glass substrate with ITO for organic EL is formed. In addition to patterning by applying a photoresist to a glass substrate and etching the glass substrate, a glass mold is formed by a similar method, and a UV-curable resist is transferred onto the glass substrate by a nanoimprinting method. An etching method is also possible. In addition, the pattern formed on the glass substrate is transferred to a mold by a technique such as nickel electroforming, and the mold is transferred to a resin by a nanoimprint technique. Is possible.

  In the organic EL element using the light extraction and / or light collecting sheet as described above, the front luminance amplification factor is increased. The light extracted in this way has a chromaticity of CIE 1931 color system of x = 0.33 ± 0.07, y = 0.33 when the 2 ° C. viewing angle front luminance is measured by the above method. The so-called white light in the range of ± 0.07 is adjusted.

  Usually, the emission color is classified into blue light from 420 nm to less than 500 nm, blue light from 500 nm to less than 550 nm, and red light from 600 nm to less than 650 nm. Therefore, although it varies depending on the material (substantially dopant) that emits light, in the present invention, the front luminance peak value of the organic electroluminescence element when there is no light extraction and / or light collecting sheet is compared with the case where the sheet is present. Qualitatively, blue is the smallest ratio.

  Since the blue color is generally rate-determined in the lifetime in continuous driving or the like, when such a light extraction and / or condensing sheet is used, a longer lifetime can be achieved in the organic electroluminescence element. Also, the driving voltage is limited by blue, which has the largest energy gap between HOMO and LUMO. Therefore, the organic EL element with improved light extraction has a design that requires less blue front luminance. Can be lowered.

  In other words, since the blue light emitting layer can be made thin and the driving voltage can be lowered, a longer life can be achieved compared to the case where there is no light extraction and / or light collecting sheet, and this combination provides a total of white light. Can be.

  Here, the amplification factor of the front luminance by the light extraction and / or condensing sheet is determined by using a spectral radiance meter (for example, CS-1000 (manufactured by Konica Minolta Sensing)) or the like, and the emission luminance from the front (viewing at 2 ° C. The visible wavelength range is required so that the optical axis of the spectral radiance meter coincides with the normal from the light-emitting surface, with or without light extraction and / or condensing sheet. Measure and integrate the values and take the ratio.

  Next, the configuration of the organic electroluminescence (EL) element of the present invention will be described.

"Layer structure"
The organic electroluminescence (EL) device according to the present invention has at least an anode, a cathode, and a plurality of light emitting layers that emit phosphorescence between the anode and the cathode on a support substrate, and the obtained light is white, At least one light emitting layer has a structure in which a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and a cathode are laminated in this order from the anode side.

  The plurality of light-emitting layers that are constituent layers of the organic electroluminescence device according to the present invention include at least two light emission spectra having emission maximum wavelengths in the range of blue 430 nm to 480 nm, green 510 nm to 550 nm, and blue 600 nm to 640 nm, respectively. It comprises a plurality of layers, preferably three or more, and more preferably comprises three light emitting layers of blue, green and red having an emission spectrum in the above range.

  Although the preferable specific example of the layer structure in this invention which has the above structure is shown below, this invention is not limited to these.

(I) Anode / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode (ii) Anode / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / Electron transport layer / cathode buffer layer / cathode (iii) anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode (iv) anode / anode buffer layer / Hole transport layer / electron blocking layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode Here, the light emitting layer unit has a maximum emission wavelength of 430 nm to 480 nm, 510 nm to 550 nm, respectively. One having at least two light emitting layers in the range of 600 nm to 640 nm is referred to as a light emitting layer unit. Moreover, it is preferable that this unit has a nonluminous intermediate | middle layer between each light emitting layer. For example, typical examples of the light emitting layer unit are illustrated below. The light emitting layer unit is preferably sandwiched between the electron blocking layer and the hole blocking layer, but is not limited thereto as long as the claims of the present invention are satisfied.

(Iv-i) Anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer-1 / intermediate layer / light emitting layer-2 / hole blocking layer / electron transport layer / cathode buffer layer / cathode (iv- ii) Anode / anode buffer layer / hole transport layer / electron blocking layer / light emitting layer-1 / hole blocking layer / light emitting layer-2 / electron transport layer / cathode buffer layer / cathode (iv-iii) Anode / anode buffer Layer / hole transport layer / light emitting layer-1 / electron blocking layer / light emitting layer-2 / hole blocking layer / electron transport layer / cathode buffer layer / cathode (iv-iv) anode / anode buffer layer / hole transport layer / Electron blocking layer / light emitting layer-1 / intermediate layer / light emitting layer-2 / intermediate layer / light emitting layer-3 / hole blocking layer / electron transport layer / cathode buffer layer / cathode (iv-v) anode / anode buffer layer / Hole transport layer / electron blocking layer / light emitting layer-1 / hole blocking layer / light emitting layer-2 / intermediate layer / light emitting layer-3 / electron transport Layer / cathode buffer layer / cathode (iv-vi) anode / anode buffer layer / hole transport layer / light emitting layer-1 / intermediate layer / light emitting layer-2 / electron blocking layer / light emitting layer-3 / hole blocking layer / Electron transport layer / cathode buffer layer / cathode The organic electroluminescence device according to the present invention is a white light-emitting device, and has at least an anode, a cathode, and a plurality of light-emitting layers that emit phosphorescence between the anode and the cathode on a support substrate. And having at least one light emitting layer from the anode side, a hole transport layer containing an electron acceptor, an electron blocking layer containing an electron acceptor, a light emitting layer, a hole blocking layer containing an electron donor, an electron donor The material which is laminated | stacked in order of the electron carrying layer to contain, and comprises each layer is comprised from the material which satisfy | fills following formula (1-1)-(2-3).
(1-1) Ea ^{A / HTL} > Ea ^HTL
(1-2) Ea ^{A / EBL} > Ea ^EBL
(1-3) Ea ^EM > Ea ^EBL
(2-1) Ip ^{D / ETL} <Ip ^ETL
(2-2) Ip ^{D / HBL} <Ip ^HBL
(2-3) Ip ^EM <Ip ^HBL
Each term in the above formula represents the electron affinity and Ip represents the ionization potential in the material forming each layer. In addition, the values of the respective terms all represent absolute values, HTL is a material for forming a hole transport layer, ETL is a material for forming an electron transport layer, A / HTL is an electron acceptor in the hole transport layer, A / EBL is an electron acceptor in the electron blocking layer, D / HBL is an electron donor in the hole blocking layer, D / ETL is an electron donor in the electron transporting property, HBL is a material for forming the hole blocking layer, EBL is an electron The material for forming the blocking layer, EM, indicates the respective values in the host compound in the light emitting layer.

  When the hole transport layer and the electron blocking layer contain an electron acceptor, and the hole blocking layer and the electron transport layer contain an electron donor, the probability of recombination of holes and electrons in the light emitting layer is improved, and light emission occurs. Efficiency is improved.

  However, in such a configuration, in order to improve the recombination probability and improve the light emission efficiency, the material for forming the hole transport layer, the material for forming the electron blocking layer, the host material in the light emitting layer, the hole transport The electron affinity Ea of the electron acceptor in the layer and the electron acceptor in the electron blocking layer, the host material in the light emitting layer, the material forming the hole blocking layer, the material forming the electron transport layer, the positive The values of the ionization potentials Ip of the electron donor in the hole blocking layer and the electron donor in the electron transport layer (each represented by an absolute value) must satisfy the above formulas (1-1) to (2-3). There is.

That is, the electron affinity Ea ^{A / HTL} of the electron acceptor in the hole transport layer is larger than the electron affinity Ea ^{HTL of the} material forming the hole transport layer, and the electron affinity of the electron acceptor in the electron blocking layer. Ea ^{A / EBL} needs to be larger than the electron affinity Ea ^{HBL of the} material forming the electron blocking layer, and the ionization potential Ip ^{D / ETL} of the electron donor in the electron transport layer is the material forming the electron transport layer it is necessary that the smaller than the ionization potential Ip ^ETL, also the ionization potential Ip D ^{/ HBL} Electron donors hole blocking layer is smaller than the ionization potential Ip ^HBL materials for forming the hole blocking layer is required. As a result, the electron transport layer, the electron blocking layer, the electron transport layer, and the hole blocking layer are not damaged. And by including in the hole blocking layer and the electron blocking layer, the amount of generated carriers is increased, and as a result, the light emission efficiency is improved.

In addition, the material for forming the host compound and the electron blocking layer in the light emitting layer is Ea ^EM > Ea ^EBL . Similarly, the material for forming the light emitting layer host compound and the hole blocking layer is Ip ^EM <Ip ^HBL . is there.

  The materials other than the electron acceptor in the hole transport layer and the electron blocking layer, that is, the material forming the hole transport layer and the material forming the electron blocking layer are different as the hole transport material and the electron blocking material. Preferably it is.

  Similarly, in the electron transport layer and the hole blocking layer, it is preferable that the material for forming the electron transport layer other than the electron donor and the material for forming the hole blocking layer are selected from different materials so as to be optimized.

  In addition, the same electron acceptor in the hole transport layer or electron blocking layer may be used, or different ones may be used as long as they satisfy the above formulas.

  Similarly, the same electron donor may be used in the electron transport layer and the hole blocking layer, or different electron donors may be used as long as each satisfies the above formula.

Here, the material for forming the electron blocking layer has a relationship of Ea ^EM > Ea ^EBL with the light emitting layer, blocks the movement of electrons from the light emitting layer and confines it in the light emitting layer, thereby improving the light emission efficiency. Similarly, the material that forms the hole blocking layer has a relationship of Ip ^EM <Ip ^HBL with the light emitting layer, and similarly suppresses the movement of holes from the light emitting layer. This contributes to improvement in luminous efficiency.

  The at least one light emitting layer in the above relational expression is adjacent to the electron blocking layer and the hole blocking layer, thereby increasing the amount of carriers generated and the efficiency of electron-hole recombination in the light emitting layer. Can be increased, which is preferable.

  The hole transport layer containing the electron acceptor and the electron blocking layer are preferably adjacent to each other, or the electron transport layer containing the electron donor and the hole blocking layer are preferably adjacent to each other. Carrier mobility is improved.

  Next, the electron affinity and ionization potential of each material constituting these organic EL materials will be described.

  The ionization potential and electron affinity are determined based on the vacuum level.

  The ionization potential is defined as the energy required to release an electron at the HOMO (highest occupied molecular orbital) level of a compound to the vacuum level, and the electron affinity is the LUMO (lowest value) of the electron at the vacuum level. It is defined as the energy that falls to the (empty molecular orbital) level and stabilizes.

  In the present invention, first, the band gap is obtained by measuring the absorption spectrum of the deposited film when the sample compound is deposited on glass to a thickness of 100 nm and converting the wavelength Ynm of the absorption edge into XeV. At this time, the following conversion formula is used.

Y = 107 / (8065.541 × X)
Further, the ionization potential can be directly measured by photoelectron spectroscopy or can be obtained by correcting the electrochemically measured oxidation potential with respect to the reference electrode. In the latter case, for example, when a saturated sweet potato electrode (SCE) is used as a reference electrode, ionization potential = oxidation potential (vs. SCE) +4.3 eV (“Molecular Semiconductors”, Springer-Verlag, 1985). Year, page 98).

  In the present invention, the ionization potential Ip of the sample compound was directly measured by photoelectron spectroscopy. Specifically, it was a value measured by a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  The electron affinity is determined from the measurement of the band gap according to the following formula, which is a definition formula of the band gap.

(Band gap) = (ionization potential)-(electron affinity)
In the present invention, in each layer constituting the organic electroluminescence element, at least 80% by mass or more of the total material constituting each layer may be a material having a glass transition temperature (Tg) of 100 ° C. or more. Preferably, by using a material having a high Tg as the organic electroluminescence element material, an organic compound layer (also referred to as an organic layer) of the organic EL element, a uniform film property can be obtained over the entire layer, and the lifetime of the element is increased. Can be improved.

<Light emitting layer>
In the light emitting layer according to the present invention, electrons injected through the electrode, the electron transport layer and the hole blocking layer, and holes injected from the electrode, the hole transport layer and the electron blocking layer are recombined. The light emitting portion may be in the light emitting layer or at the interface between the light emitting layer and the adjacent layer. The light emitting layer according to the present invention has at least three light emitting layers: a light emitting layer A having a light emission maximum wavelength in the range of 430 nm to 480 nm, a light emitting layer B in the range of 510 nm to 550 nm, and a light emitting layer C in the range of 600 nm to 640 nm. It is preferable to have layers A, B, and C, but a two-color configuration is also acceptable. For example, even if a two-color light-emitting layer having a light-emitting region in the light-emitting range of the light-emitting layer A, the light-emitting layer B, and the light-emitting layer C is selected, white color is obtained although the color reproducibility is inferior to the three-color configuration. .

  In addition, when the number of light emitting layers is more than four, there may be a plurality of layers having the same emission spectrum or emission maximum wavelength. In the present invention, a layer having an emission maximum wavelength in the range of 430 nm to 480 nm is hereinafter referred to as a blue light emitting layer, a layer in the range of 510 nm to 550 nm is referred to as a green light emitting layer, and a layer in the range of 600 nm to 640 nm is hereinafter referred to as a red light emitting layer. Although there is no restriction | limiting in particular as a lamination order of a light emitting layer, It is preferable that the light emitting layer with the lowest recombination probability is pinched | interposed with the electron blocking layer and hole blocking layer of this invention. This example is often a blue light emitting layer. Moreover, it is preferable to have a non-light emitting intermediate | middle layer between each light emitting layer. The total thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of a high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust to the range of 2 nm to 30 nm, and more preferably in the range of 5 nm to 25 nm. For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed and formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can. The thickness of each light emitting layer may be arbitrary as long as it is in the above-described range. Although there is no restriction | limiting in particular about the film thickness relationship of each blue, green, and red light emitting layer, In order to obtain white light, the film thickness of the light emitting layer with a low recombination probability becomes the thickest. Moreover, in the range which maintains the said maximum wavelength, you may mix a several luminescent compound in each light emitting layer. For example, a blue light emitting layer may be used by mixing a blue light emitting compound having a maximum wavelength of 430 nm to 480 nm and a green light emitting compound having a maximum wavelength of 510 nm to 550 nm.

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

(Host compound)
The host compound contained in the light emitting layer of the organic EL device according to the present invention is defined as a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer. As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of phosphorescent compounds etc. which are used as the light emission dopant mentioned later, and thereby, arbitrary luminescent colors can be obtained. It is possible to adjust the kind of phosphorescent compound and the amount of doping, and it can be applied to illumination and backlight.

  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 (triarylborane derivative), a nitrogen-containing heterocyclic compound, Those having a basic skeleton such as a thiophene derivative, a furan derivative, an oligoarylene compound, or a carboline derivative or a diazacarbazole derivative (here, a diazacarbazole derivative is at least a hydrocarbon ring constituting a carboline ring of a carboline derivative) Represents one in which one carbon atom is substituted with a nitrogen atom.) And the like.

  As the host compound according to the present invention, a compound represented by the following general formula (1) is preferably used. Moreover, the said compound is preferably used also for the adjacent layer (for example, hole-blocking layer etc.) of a light emitting layer.

In the formula, Z ₁ represents an aromatic heterocyclic ring which may have a substituent, Z ₁ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may each have a substituent, and Z ₂ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent. In the general formula (1), examples of the aromatic heterocycle represented by Z ₁ and Z ₂ include a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, Diazole 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, carboline ring And a ring in which the carbon atom of the hydrocarbon ring is further substituted with a nitrogen atom. Furthermore, the aromatic heterocyclic ring may have a substituent represented by R ₁₀₁ described later. In the general formula (1), examples of the aromatic hydrocarbon ring represented by Z ₂ include benzene ring, biphenyl ring, naphthalene ring, azulene ring, anthracene ring, phenanthrene ring, pyrene ring, chrysene ring, naphthacene ring, triphenylene. Ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene Ring, pyranthrene ring, anthraanthrene ring and the like. Furthermore, the aromatic hydrocarbon ring may have a substituent represented by R ₁₀₁ described later. In the general formula (1), examples of the substituent represented by R ₁₀₁ include an alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group). 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.) Etc.), aryl groups (eg phenyl group, naphthyl group etc.), aromatic heterocyclic groups (eg furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group) , Thiazolyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg Pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cyclo An alkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), an aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), an alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, Octylthio group, dosylthio group, etc.), cycloalkylthio group (for example, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (for example, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (for example, methylothio group, etc.) Sicarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, Aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2 -Pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexyl group) Rucarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group) Octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonyl) Amino group, 2-ethylhexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcal Bonylamino 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, dodecyl group) Ureido group, phenylureido group naphthylureido group, 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfide group) Nyl 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, 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 Etc.), halogen atoms (eg fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon groups (eg fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group etc.), cyano group Nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.). 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. Preferred substituents are an alkyl group, a cycloalkyl group, a fluorinated hydrocarbon group, an aryl group, and an aromatic heterocyclic group. As the divalent linking group, in addition to hydrocarbon groups such as alkylene, alkenylene, alkynylene, and arylene, those containing a hetero atom may be used, and a thiophene-2,5-diyl group, pyrazine-2, It may be a divalent linking group derived from a compound having an aromatic heterocyclic ring (also called a heteroaromatic compound) such as a 3-diyl group, or may be a chalcogen atom such as oxygen or sulfur. . Further, it may be a group such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group that connects and connects heteroatoms. A mere bond is a bond that directly bonds the connecting substituents together. In the present invention, Z _{1 in the} general formula (1) is preferably a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased. In the present invention, it is preferable that the Z ₂ in the general formula (1) is a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased. Furthermore, it is preferable that Z ₁ and Z _{2 in} the general formula (1) are both 6-membered rings because the luminous efficiency can be further increased. Furthermore, it is preferable because the lifetime can be further increased. Hereinafter, specific examples of the compound represented by the general formula (1) according to the present invention and the carbazole derivative will be shown.

  Specific examples of the carboline derivative and diazacarbazole derivative represented by the general formula (1) further include compound examples described in paragraphs (0136) to (0170) of Japanese Patent Application No. 2004-305349.

The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (deposition polymerization property). (Light emitting host). As the known host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable. Specific examples of known host compounds include compounds described in the following documents. 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, at least three light emitting layers A, a light emitting layer A having a light emission maximum wavelength in the range of 430 nm to 480 nm, a light emitting layer B in the range of 510 nm to 550 nm, and a light emitting layer C in the range of 600 nm to 640 nm, B and C, but 50% by mass or more of the host compounds of at least two layers of the three layers each have a phosphorescence emission energy of 2.9 eV or more and a Tg (glass transition point) of 90 ° C. or more. These compounds are preferred, and more preferred are compounds at 100 ° C. or higher. Among these, from the viewpoint of improving the storage stability of organic EL elements (also referred to as durability improvement) and reducing the uneven distribution of the compound at the light emitting layer interface, the molecular structures of the compounds are preferably the same. Here, the reason why it is preferable that the host compounds have the same physicochemical characteristics or the same molecular structure will be described in detail in the non-light emitting intermediate layer described later.

(Tg (glass transition point))
The organic compound of each layer constituting the organic electroluminescent element of the present invention is characterized by containing a material having a Tg of 100 ° C. or higher at least 80% by mass or more of the total material of each layer.
Here, the glass transition point (Tg) is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry). By using a host compound having the same physical characteristics as described above, and more preferably by using a host compound having the same molecular structure, the entire organic compound layer (also referred to as an organic layer) of the organic EL element is used. Homogeneous film properties can be obtained, and furthermore, adjusting the phosphorescence emission energy of the host compound to be 2.9 eV or more can effectively suppress the energy transfer from the dopant and obtain high luminance. I can do it.

(Luminescent dopant)
The light emitting dopant according to the present invention will be described. As the light-emitting dopant according to the present invention, a fluorescent compound or a phosphorescent emitter (also referred to as a phosphorescent compound or a phosphorescent compound) can be used. From the viewpoint of obtaining an organic EL element with higher luminous efficiency. Is a light-emitting dopant (sometimes simply referred to as a light-emitting material) used in the light-emitting layer or light-emitting unit of the organic EL device of the present invention, and at the same time contains at least one phosphorescent light-emitting material. Containing.

(Phosphorescent emitter (also called phosphorescent dopant))
The phosphorescent emitter (phosphorescent dopant) according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.). Although the yield is defined to be a compound of 0.01 or more at 25 ° C., the preferred phosphorescence quantum yield is 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence emitter according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. Just do it. There are two types of light emission of phosphorescent emitters in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent emitter. Energy transfer type to obtain light emission from the phosphorescent emitter, and another is a carrier in which the phosphorescent emitter becomes a carrier trap and recombination of carriers occurs on the phosphorescent emitter to obtain light emission from the phosphorescent emitter. Although it is a trap type, in any case, it is a condition that the excited state energy of the phosphorescent emitter is lower than the excited state energy 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. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  Specific examples of the compound used as the phosphorescent material include compounds described in paragraphs (0106) to (0109) of JP-A No. 2004-311410. The present invention is not limited to these.

(Fluorescent light emitter (also called fluorescent dopant))
Representative examples of fluorescent emitters (fluorescent dopants) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors. In addition, conventionally known dopants can also be used in the present invention. For example, WO 00/70655 pamphlet, JP 2002-280178 A, JP 2001-181616 A, JP 2002-280179 A, JP 2001-181617 A, JP 2002-280180 A, JP 2001-247859 A, JP 2002-299060 A, JP 2001-313178 A, JP 2002-302671 A, JP JP 2001-345183 A, JP 2002-324679 A, WO 02/15645 Pamphlet, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-2002 A. -83684 publication, special table 2002 JP 40572, JP 2002-117978, JP 2002-338588, JP 2002-170684, JP 2002-352960, WO 01/93642, JP 2002-50483. JP, JP-A No. 2002-1000047, JP-A No. 2002-173684, JP-A No. 2002-359082, JP-A No. 2002-175854, JP-A No. 2002-363552, JP-A No. 2002-184582 JP, 2003-7469, JP 2002-525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP JP 2002-234894, JP 002-235076, JP 2002-241751, JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-10047
No. 4, JP-A No. 2002-203679, JP-A No. 2002-343572, JP-A No. 2002-203678, and the like.

<Non-light emitting intermediate layer>
The non-light emitting intermediate layer according to the present invention will be described. The non-light-emitting intermediate layer according to the present invention means each light emission of the light-emitting layer unit having at least three light-emitting layers having emission maximum wavelengths in the range of 430 nm to 480 nm, 510 nm to 550 nm, and 600 nm to 640 nm, respectively. Between the layers.

  The film thickness of the non-light emitting intermediate layer is preferably in the range of 1 nm to 15 nm, and more preferably in the range of 3 nm to 10 nm to suppress interaction such as energy transfer between adjacent light emitting layers, and This is preferable from the viewpoint of not applying a large load to the current-voltage characteristics of the 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 the case where the physicochemical characteristics such as luminescence energy and glass transition point are the same or the molecular structure of the host compound is the same, etc.), the injection barrier between the light emitting layer and the non-light emitting layer is contained. Thus, even if the voltage (current) is changed, the hole and electron injection balance can be easily maintained. It has also been found that the effect of improving the color shift when a voltage (current) is applied can be obtained. Furthermore, the host compound contained in each light emitting layer in the undoped light emitting layer is a major problem in the conventional organic EL device production by using a host material having the same physical characteristics or the same molecular structure. The complexity of device fabrication can also be eliminated.

Furthermore, by using a material in which the lowest excited triplet energy level T _{1 of} the common host material is higher than the lowest excited triplet energy level T _{2 of} the phosphorescent emitter, Since triplet excitons are effectively confined in the light emitting layer, a highly efficient device can be obtained. In addition, in the organic EL element of three colors of blue, green, and red, when a phosphorescent emitter is used for each light emitting material, the excited triplet energy of the blue phosphorescent emitter is the largest, A host material having an excited triplet energy larger than that of the phosphorescent emitter may be included as a common host material in the light emitting layer and the non-light emitting intermediate layer. 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. On the other hand, 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, that is, a hole blocking layer and an electron blocking layer. It is done.

  In the white light-emitting organic EL device of the present invention, the film thickness including the respective light-emitting layers and the non-light-emitting intermediate layer between the different light-emitting layers closest to the anode and the cathode is preferably 5 to 30 nm. . If it is larger than this, the drive voltage required for light emission will increase. On the other hand, if the thickness is 5 nm or less, the light emission efficiency is lowered and defects are likely to occur.

  Hereinafter, the carrier donor doped in the carrier transport layer and the carrier blocking layer of the present invention will be described. In the organic EL device according to the present invention, the hole transport layer and the electron blocking layer, or the electron transport layer and the hole blocking layer are doped with an electron acceptor and an electron donor, respectively. Can be raised. As a result, the conductivity is improved and the light emission efficiency is improved.

Electron acceptors doped in the hole transport layer and the electron blocking layer include Au, Pt, W, Ir, POCl ₃ , AsF ₆ , Cl, Br, I and other inorganic materials, TCNQ (7, 7, 8 , 8, -tetracyanoquinodimethane), F4-TCNQ (tetrafluorotetracyanoquinodimethane), TCNE (tetracyanoethylene), HCNB (hexacyanobutadiene), DDQ (dicyclodicyanobenzoquinone) and the like. Examples thereof include compounds, compounds having a nitro group such as TNF (trinitrofluorenone) and DNF (dinitrofluorenone), and organic materials such as fluoranyl, chloranil and bromanyl. Among these, compounds having a cyano group such as TCNQ, F4-TCNQ, TCNE, HCNB, DDQ, etc. are more preferable.

  In addition, it is preferable that the addition ratio of the acceptor with respect to the hole transport material in the hole transport layer or the electron blocking layer or the material forming the same is 1 to 20% by mass.

  In addition, as an electron donor doped in the electron transport layer and the hole blocking layer, alkali metals or alkaline earth metals and salts thereof, rare earth elements, inorganic materials such as Al, Ag, Cu, In, anilines, Phenylenediamines, benzidines (N, N, N ′, N′-tetraphenylbenzidine, N, N′-bis- (3-methylphenyl) -N, N′-bis- (phenyl) -benzidine, N, N'-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine, etc.), triphenylamines (triphenylamine, 4,4 ', 4 "-tris (N, N-diphenyl-amino) -Triphenylamine, 4,4 ', 4 "-tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine, 4,4', 4" -tris (N- (1-naphth ) -N-phenyl-amino) -triphenylamine, etc.), triphenyldiamines (N, N'-di- (4-methyl-phenyl) -N, N'-diphenyl-1,4-phenylenediamine) Compounds having an aromatic tertiary amine as a skeleton, condensed polycyclic compounds such as pyrene, perylene, anthracene, tetracene and pentacene (however, the condensed polycyclic compound may have a substituent), TTF (tetrathiafur Organic compounds such as valene), etc. Among these, compounds having an aromatic tertiary amine as a skeleton and condensed polycyclic compounds are more preferable, and the addition ratio of the donor to the electron transport material is 1 to 20% by mass. Preferably there is.

  Hereinafter, the carrier transport layer and the carrier blocking layer of the present invention will be described. In addition, the carrier of this invention points out an electron or a hole. In general, the hole transport layer is made of a material having the ability to transport holes, and includes a hole injection layer and an electron blocking layer in a broad sense. Similarly, the electron transport layer is made of a material having the ability to transport electrons, and includes an electron injection layer and a hole blocking layer in a broad sense. In the present invention, the characteristic values described in claim 1 are further satisfied while having the capability of each of the above layers. That is, the electron blocking layer has a higher LUMO energy level than the hole transport layer, and the hole blocking layer has a lower HOMO energy level than the electron transport layer. For this reason, it becomes one of the causes of a decrease in the drive voltage, which is different from the object of the present invention, but is useful for reducing the leakage.

《Hole transport layer》
The hole transport layer can be provided as a single layer or a plurality of layers. The hole transport material for forming the hole transport layer 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 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) etc. Further, 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. An inorganic compound such as SiC can also be used as a hole injecting material and a hole transporting material. It is also possible to use a so-called p-type hole transport material as described in p.139). Since the obtained, it is preferable to use these materials. The hole transport layer may be formed into a thin film from the hole transport material together with the electron acceptor by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Can be formed. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, about 1 nm-1 micrometer, 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. Impurities may be doped, and examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. 95, 5773 (2004), and the like. Moreover, general formula (1)-(7) in Japanese Patent Application No. 2004-215727 is also preferably used.

《Electron blocking layer》
In a broad sense, the material that forms this in the electron blocking layer when functioning as an electron blocking region is a material that has a hole transport function and has a very small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes in the light emitting layer can be improved. The material of the electron blocking layer of the present invention has a higher LUMO level than the host material of the hole transport layer and the adjacent light emitting layer. Therefore, the materials of these layers are different. This energy gap preferably has an electron affinity different by 0.2 eV or more from the viewpoint of improving the luminance of the organic electroluminescence device of the present invention. The electron affinity is defined by the energy released when electrons are injected from the vacuum level to the LUMO level of the compound. The electron affinity can be measured by a known method such as photoelectron spectroscopy. The electron blocking layer may be doped with impurities. The same material as that of the above-described hole transport layer is applied as the impurity used. In the present invention, the electron acceptor is also doped in the electron blocking layer. The thickness of the electron blocking layer is about 1 nm to 20 nm, preferably 3 nm to 10 nm. These widths are set in order to increase exciton generation efficiency and minimize the increase in drive voltage.

《Electron transport layer》
The electron transport layer can be provided as a single layer or a plurality of layers. Conventionally, in the case of a single electron transport layer and a plurality of layers, 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 transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide 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. The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 1 nm-1 micrometer, Preferably it is 5 nm-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials. Further, an electron transport layer having high n property doped with impurities may 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. Moreover, general formula (8)-(10) in Japanese Patent Application No. 2004-215727 is also preferably used.

(Hole blocking layer)
The hole blocking layer is an electron transport layer in a broad sense, and is made of a material that has a function of transporting electrons and has a very small ability to transport holes, and emits light by blocking holes while transporting electrons. The probability of recombination of electrons and holes in the layer can be improved. Therefore, the applied material is selected from the electron transport materials described above. The material of the electron blocking layer of the present invention has a lower HOMO level than the host material of the electron transport layer and the adjacent light emitting layer. Therefore, the materials of these layers are different. This energy gap preferably has a different ionization potential of 0.2 eV or more from the viewpoint of improving the luminance of the organic electroluminescence device of the present invention. The ionization potential is defined by the energy required to emit electrons at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level. In addition to the above-described photoelectron spectroscopy method, for example, the following method It can ask for.

  Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), molecular orbital calculation software manufactured by Gaussian, USA, as a keyword, B3LYP / The ionization potential can be obtained as a value obtained by rounding off the second decimal place of a value (eV unit converted value) calculated by performing structure optimization using 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

  Further, the hole blocking layer may be doped with impurities. The same material as that of the above-described electron transport layer is applied as the impurity used. The film thickness of the hole blocking layer is about 1 nm to 20 nm, preferably 3 nm to 10 nm. These widths are set in order to increase exciton generation efficiency and minimize the increase in drive voltage. Use of at least one of styryl compounds, triazole derivatives, phenanthroline derivatives, oxadiazole derivatives, and boron derivatives as the hole blocking material is also effective in obtaining the effects of the present invention. Examples of other compounds include exemplified compounds described in JP-A Nos. 2003-31367, 2003-31368, and Japanese Patent No. 2721441.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be. An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene. The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by 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 the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
As described above, 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 concerning this invention as needed. The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  Further, in the present invention, a plurality of light emitting layers having different emission colors are provided. In such a case, it is preferable that the light emitting layer whose emission maximum wavelength is the shortest is the closest to the anode among all the light emitting layers. However, in such a case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.2 eV or more larger than the host compound of the shortest wave 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.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. 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, or when the pattern accuracy is not required (about 100 μm or more) ), 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.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al2O3) mixture. , 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, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. 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.

《Support base》
The support substrate (hereinafter also referred to as a substrate, a substrate, a substrate, a support, etc.) according to the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent or opaque. It may be. In the case where light is extracted from the support base side, the support base is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support base 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 in accordance with JIS K 7129-1992 is 0.01 g / m ^2. It is preferably a barrier film of day · atm or less, and further, the oxygen permeability measured by a method according to JIS K 7126-1992 is 10 ⁻³ g / m ² / day or less, water vapor permeability Is preferably a high barrier film of 10 ⁻³ g / m ² / day or less, and the water vapor permeability and oxygen permeability are both 10 ⁻⁵ g / m ² / day or less, Further preferred. As a material for forming a barrier film formed on the surface of the resin film in order to obtain a high barrier film, any material may be used as long as it has a function of suppressing intrusion of an element such as moisture or oxygen that causes deterioration of the element. Silicon, 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.

<Method for forming barrier film>
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 weighting. A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma discharge treatment method described in JP-A-2004-68143 is particularly preferable. Examples of the opaque support base include metal plates / films such as aluminum and stainless steel, opaque resin substrates, ceramic substrates, and the like.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100. In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor.

  Here, an example of a layer structure of a transparent barrier film used for the support base according to the present invention will be described with reference to FIG. 1, and an example of an atmospheric pressure plasma discharge treatment apparatus preferably used for forming the barrier layer will be described with reference to FIG. Will be described. FIG. 1 is a schematic diagram illustrating an example of a layer configuration of a barrier film (also referred to as a gas barrier film) and a density profile thereof. The barrier film 201 (which may be transparent or opaque) has a configuration in which layers having different densities are stacked on the base material 202. In the present invention, a medium density layer 204 is provided between the low density layer 203 and the high density layer 205, and the medium density layer 204 is also provided on the high density layer 205, and these low density layer and medium density layer are provided. FIG. 1 shows an example in which a unit composed of a high-density layer and a medium-density layer is one unit, and two units are stacked. At this time, the density distribution in each density layer is uniform, and the density change between adjacent layers is stepped. In FIG. 1, the medium density layer 204 is shown as one layer, but a configuration of two or more layers may be adopted as necessary. In addition, as a layer structure of the barrier film (gas barrier film) according to the present invention, at least one layer among the three layers having different densities (a high density layer, a medium density layer, and a low density layer) may be provided. Preferably, it has two or three layers with different densities.

Here, an atmospheric pressure plasma discharge processing apparatus as shown in FIG. 2 is used as an example for forming the high density layer, the medium density layer, and the low density layer. Examples of the set values of the density of the high-density layer, medium-density layer, and low-density layer, materials used for forming each layer (for example, silicon oxide, silicon oxynitride, alumina oxide, etc.) and formation conditions are shown in the examples. This will be specifically described in FIG. FIG. 2 is a schematic view showing an example of an atmospheric pressure plasma discharge treatment apparatus for treating a substrate. The atmospheric pressure plasma discharge processing apparatus is an apparatus having at least a plasma discharge processing apparatus 230, an electric field applying means 240 having two power supplies, a gas supply means 250, and an electrode temperature adjusting means 260. FIG. 2 shows an interval (discharge space) 232 between the roll rotating electrode (first electrode) 235 and the square tube type fixed electrode group (second electrode) 236 (each electrode is also a square tube type fixed electrode 236). Thus, the substrate F is subjected to plasma discharge treatment to form a thin film. In FIG. 2, a pair of rectangular tube type fixed electrode group (second electrode) 236 and roll rotating electrode (first electrode) 235 form one electric field. Is formed. FIG. 2 shows a configuration example in which a total of five units having such a configuration are provided. In each unit, the type of raw material to be supplied, the output voltage, and the like are controlled arbitrarily and independently. A mold barrier film (also referred to as a transparent gas barrier layer) can be formed continuously. In the discharge space (between the counter electrodes) 232 between the roll rotating electrode (first electrode) 235 and the square tube type fixed electrode group (second electrode) 236, the roll rotating electrode (first electrode) 235 has a first power source. The first high-frequency electric field having the frequency ω1, the electric field intensity V1, and the current I1 from 241 and the frequency ω2, the electric field intensity V2 from the corresponding second power source 242 to the rectangular tube fixed electrode group (second electrode) 236, respectively. A second high-frequency electric field of current I2 is applied. A first filter 243 is installed between the roll rotation electrode (first electrode) 235 and the first power source 241. The first filter 243 easily passes a current from the first power source 241 to the first electrode. In addition, the current from the second power source 242 is grounded so that the current from the second power source 242 to the first power source is difficult to pass. In addition, a second filter 244 is installed between the square tube type fixed electrode group (second electrode) 236 and the second power source 242, and the second filter 244 is connected to the second electrode from the second power source 242. It is designed so that the current from the first power source 241 is grounded and the current from the first power source 241 to the second power source is difficult to pass. The roll rotating electrode 235 may be the second electrode, and the square tube fixed electrode group 236 may be the first electrode. In any case, the first power source is connected to the first electrode, and the second power source is connected to the second electrode. The first power source preferably applies a higher high-frequency electric field strength (V1> V2) than the second power source. Further, the frequency has the ability to satisfy ω1 <ω2. The current is preferably I1 <I2. Current I1 of the first high-frequency electric field is preferably ^{0.3mA / cm 2 ~20mA / cm 2} , more preferably at ^{1.0mA / cm 2 ~20mA / cm 2} . Furthermore, current I2 of the second high-frequency electric field is preferably ^{10mA / cm 2 ~100mA / cm 2} , more preferably ^{20mA / cm 2 ~100mA / cm 2} . The gas G generated by the gas generator 251 of the gas supply means 250 is introduced into the plasma discharge processing container 231 from the air supply port while controlling the flow rate. The base material F is unwound from the original winding (not shown) and is transported, or transported from the previous process, and air or the like accompanying the base material is blocked by the nip roll 265 via the guide roll 264. Then, while being wound while being in contact with the roll rotating electrode 235, it is transferred between the square tube fixed electrode group 236, the roll rotating electrode (first electrode) 235 and the square tube fixed electrode group (second electrode) 236, An electric field is applied from both sides to generate discharge plasma between the counter electrodes (discharge space) 232. The base material F forms a thin film with a gas in a plasma state while being wound while being in contact with the roll rotating electrode 235. The substrate F passes through the nip roll 266 and the guide roll 267, and is taken up by a winder (not shown) or transferred to the next process. Discharged treated exhaust gas G ′ is discharged from the exhaust port 253. In order to heat or cool the roll rotating electrode (first electrode) 235 and the rectangular tube type fixed electrode group (second electrode) 236 during the thin film formation, a medium whose temperature is adjusted by the electrode temperature adjusting means 260 is used as a liquid feed pump. P is sent to both electrodes via the pipe 261, and the temperature is adjusted from the inside of the electrode. Reference numerals 268 and 269 denote partition plates that partition the plasma discharge processing vessel 231 and the outside.

<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 base 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 element can be thinned.

Furthermore, the polymer film preferably has an oxygen permeability of 10 ⁻³ g / m ² / day or less and a water vapor permeability of 10 ⁻⁵ g / m ² / day or less. Further, it is more preferable that both the water vapor permeability and the oxygen permeability are 10 ⁻⁵ g / m ² / day 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 (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). Metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, barium perchlorate, In particular, 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, but the polymer film is light and thin. Is preferably used.

<< 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 base 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. 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, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. From the point of being difficult to form, a vacuum deposition method, a spin coating method, an ink jet method, and a printing method are particularly preferable. Further, different film forming methods may be applied for each layer. When a vapor deposition method is employed 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. It is desirable to select appropriately within the range of 01 nm / second to 50 nm / second, substrate temperature −50 ° C. to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 nm 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.

<Application>
The organic electroluminescence element of the present invention can be used as a display device, a display, or various light 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 especially as a backlight of a liquid crystal display device combined with a color filter and a light source for illumination. In the organic electroluminescence element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. 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.

<Display device>
The display device of the present invention will be described. The display device 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 a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, 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 manufacturing order is reversed, and 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 2V to 40V with the anode as + and the cathode as-. 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. Light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. Although it is mentioned, it is not limited to these.

《Lighting device》
The lighting device of the present invention will be described. The organic EL element of the present invention may be used as a kind of lamp such as an illumination or exposure light source, or 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. When used as a display device for reproducing moving images, the driving method 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 material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, an arbitrary material is selected from the light emitting materials so as to be adapted to the wavelength range corresponding to the CF (color filter) characteristics. In combination, or in combination with the light extraction and / or condensing sheet, it may be whitened.

  As described above, the white organic EL element used in the present invention is combined with CF (color filter), and the element and the driving transistor circuit are arranged in accordance with the CF (color filter) pattern. As described, white light extracted from the organic electroluminescence device is used as a backlight, blue light (having a light emission maximum in the range of 430 nm to 480 nm), green light (through a blue filter, a green filter, and a red filter) A light emitting maximum in a wavelength range of 510 nm to 550 nm) and red light (having a light emission maximum in a wavelength range of 600 nm to 640 nm) can be obtained, and a long-life full-color organic electroluminescence display can be obtained with a low driving voltage. .

  In addition to these displays, various light-emitting light sources and lighting devices are also useful for home lighting, interior lighting, and as a kind of lamp such as an exposure light source for display devices such as backlights for liquid crystal display devices. It is done. Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

  The organic EL element materials used in the examples are shown below.

Example 1
<< Preparation of Organic Electroluminescence Element 101 >>
Transparent support with this ITO transparent electrode after patterning on a substrate (also referred to as a support substrate) in which ITO (Indium Tin Oxide) is deposited to a thickness of 120 nm on a glass substrate of 30 mm × 30 mm and a thickness of 0.5 mm as an anode The substrate (101 in FIG. 1) was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support base was fixed to a substrate holder of a commercially available vacuum deposition apparatus. F4-TCNQ, m-MTDATA, EB, HB, BCzVBi (fluorescent B), compound 1 (host compound), Ir-1 (phosphorescent G), Ir-9 (phosphorescent) are attached to each of the vapor deposition crucibles in the vacuum vapor deposition apparatus. R), BCP, and CsF (cesium fluoride) were filled in amounts optimal 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 4 × 10 ⁻⁴ Pa, the vapor deposition crucible containing F4-TCNQ and m-MTDATA is energized and heated, so that the total vapor deposition rate is such that F4-TCNQ is 2 mass%. Vapor deposition was performed on the ITO electrode side of the transparent support base at 0.1 nm / second, and a 40 nm hole transport layer containing an acceptor was provided. Further, the energization crucible loaded with each material is energized so that each layer is formed with the materials and mixing ratios shown in Table 1, and is co-deposited or vapor-deposited on the hole transport layer, followed by the electron blocking layer. The light emitting layer 1, the intermediate layer 1, the light emitting layer 2, the intermediate layer 2, the light emitting layer 3, the hole blocking layer, and the electron transporting layer were formed. Finally, aluminum 110 nm was vapor-deposited to form a cathode, and an organic EL device 101 was produced.

  Finally, in a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more), the organic electroluminescence element is covered with a glass case, and the organic electroluminescence element 101 is covered with a glass case. Was sealed without contact with the atmosphere. 3 and 4 are sectional views of the lighting device thus manufactured. In FIGS. 3 and 4, 15 is a cathode, 16 is an organic EL layer composed of the above layers, 17 is a transparent electrode, and 11 is a glass substrate. The glass case 12 is filled with nitrogen gas 18 and a water catching agent 19 is provided.

<< Preparation of organic electroluminescence elements 102-111 >>
Elements 102 to 111 were produced in the same manner as the element 101 except that each layer of the organic electroluminescent element 101 was changed to the mixing ratio and film thickness shown in Table 1. The element 105 has a structure in which an electron blocking layer is provided as an intermediate layer between the light emitting layer 1 and the light emitting layer 2 and a hole blocking layer is provided between the light emitting layer 2 and the light emitting layer 3.

  In Table 1, the numbers in () represent mass%.

  In the present invention, in order to obtain the electron affinity Ea and the ionization potential Ip of the material forming each layer used, first, the band gap is vapor deposited to 100 nm on each material, and the absorption spectrum of the vapor deposition film is obtained. Measurement was performed by converting the wavelength Ynm of the absorption edge into XeV. The following conversion formula is used.

Y = 107 / (8065.541 × X)
The ionization potential Ip is a value measured by photoelectron spectroscopy, specifically, a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd., and the electron affinity is determined from the measurement of the band gap. The ionization potential obtained according to the following formula, which is the definition formula of

(Band gap) = (ionization potential)-(electron affinity)
The obtained Ea and Ip of each material are shown below.

  Evaluation was made for each of the fabricated devices.

<Evaluation of element sealing treatment and front luminance>
The front luminance of each element produced as described above was evaluated. Here, all the elements have a chromaticity in the range of X = 0.33 ± 0.07 and Y = 0.33 ± 0.07 in the CIE1931 color system at a 2 ° C. viewing angle front luminance of 1000 cd / m ^2. Yes, it was confirmed to be white. The device was evaluated by measuring the driving voltage and life of the device when the device was made to emit light at a constant luminance (1000 cd / cm ² ). In addition, it continued driving with the initial electric current value which gives the light-emission brightness | luminance of 1000 cd / m < ² >, and time (hr) until a brightness | luminance is reduced to half was defined as the lifetime. The obtained results are shown in Table 3.

  The structure of the present invention, that is, the hole transport layer and the electron blocking layer contain an electron acceptor, and the hole blocking layer and the electron transport layer contain an electron donor, and the material forming each layer It can be seen that in the device in which Ea and Ip satisfy the relationship described in the claims, the driving voltage is lowered (that is, the light emission efficiency is improved) and the lifetime is also extended.

  This is presumably because the electron acceptor in the electron blocking layer or the like and the electron donor in the hole blocking layer or the like greatly contributes to the increase in the carrier supply amount.

Example 2
A sample 201 was produced in exactly the same manner as the sample 109 of Example 1 except as described below. Light was emitted under the same conditions as in Sample 109 of Example 1. However, in addition to having the structure of the present invention, an organic EL panel with higher brightness and flexibility was produced.

  That is, the glass substrate was changed to the following film substrate.

  As a substrate, on a polyethylene terephthalate film having a thickness of 100 μm (a film made by Teijin-Dyupon Co., Ltd., hereinafter abbreviated as PEN), with the atmospheric pressure plasma discharge treatment apparatus and discharge conditions shown below, the profile configuration shown in FIG. Unlike FIG. 1, another unit of low density layer, medium density layer, high density layer, and medium density layer was further provided, and a support base (gas barrier film) having a transparent barrier layer in which three layers were laminated was produced.

(Atmospheric pressure plasma discharge treatment equipment)
The configuration of the atmospheric pressure plasma discharge treatment apparatus 230 used for the production is shown in FIG. A roll electrode covered with a dielectric and a set of a plurality of rectangular tube electrodes were produced as follows.

  A roll rotating electrode 235 serving as a first electrode covers a titanium alloy T64 jacket roll metallic base material having cooling means by cooling water by coating a high density, high adhesion alumina sprayed film by an atmospheric pressure plasma method. The roll diameter was set to 1000 mmφ. On the other hand, the square electrode of the second electrode is a rectangular tube-shaped fixed electrode group 236 which is coated with 1 mm of the same dielectric material as the above on a hollow rectangular tube-shaped titanium alloy T64 under the same conditions, and is opposed thereto. It was.

Twenty-four square tube electrodes 236 were arranged around the roll rotating electrode 235 with a counter electrode gap of 1 mm. The total discharge area of the rectangular tube type fixed electrode group 236 was 150 cm (length in the width direction) × 4 cm (length in the transport direction) × 24 (number of electrodes) = 14400 cm ² . In all cases, an appropriate filter was installed.

  During plasma discharge, the first electrode (roll rotating electrode) 235 and the second electrode (square tube type fixed electrode group) 236 are adjusted and maintained at 80 ° C., and the roll rotating electrode 235 is rotated by a drive to form a thin film. went. Among the 24 rectangular tube type fixed electrode groups 236, 4 from the upstream side are used for forming the following first layer (low density layer 1), and the following 6 are used for the following second layer (medium density layer 1). The following 8 pieces are used for forming the third layer (high density layer 1) and the remaining 6 pieces are used for forming the fourth layer (medium density layer 2). The conditions were set and 4 layers were stacked in one pass. This condition was further repeated twice to produce a transparent gas barrier film 1.

(First layer: low density layer 1)
Plasma discharge was performed under the following conditions to form a low density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.8% by volume
Thin film forming gas: hexamethyldisiloxane (hereinafter abbreviated as HMDSO)
(Vaporized by mixing with nitrogen gas in a Lintec vaporizer) 0.2% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed first layer (low density layer) was 1.90 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Second layer: Medium density layer 1)
Plasma discharge was performed under the following conditions to form a medium density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.9% by volume
Thin film forming gas: hexamethyldisiloxane (hereinafter abbreviated as HMDSO)
(Vaporized by mixing with nitrogen gas in a Lintec vaporizer) 0.1% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions: Only the power supply on the first electrode side was used>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
The density of the formed second layer (medium density layer) was 2.05 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Third layer: High-density layer 1)
Plasma discharge was performed under the following conditions to form a high-density layer 1 having a thickness of about 90 nm.

<Gas conditions>
Discharge gas: Nitrogen gas 94.9% by volume
Thin film forming gas: hexamethyldisiloxane (hereinafter abbreviated as HMDSO)
(Vaporized by mixing with nitrogen gas in a Lintec vaporizer) 0.1% by volume
Additive gas: Oxygen gas 5.0% by volume
<Power supply conditions>
1st electrode side Power supply type
Frequency 80kHz
Output density 10W / cm ²
Second electrode side Power supply type High frequency power supply manufactured by Pearl Industrial Co., Ltd.
Frequency 13.56MHz
Output density 10W / cm ²
The density of the formed third layer (high density layer) was 2.20 as a result of measurement by the X-ray reflectivity method using MXP21 manufactured by MacScience.

(Fourth layer: Medium density layer 2)
The medium density layer 2 was formed under the same conditions as the second layer (medium density layer 1).

(5th to 12th layers)
Under the same conditions as the formation of the first layer to the fourth layer (1 unit), this was further repeated twice to produce a gas barrier film.

  A low refractive layer using silica aerogel was provided on the gas barrier film as a substrate. This low refractive layer was produced as follows. That is, liquid A was prepared by mixing tetramethoxysilane oligomer and methanol, and liquid B was prepared by mixing water, ammonia water, and methanol. An alkoxysilane solution obtained by mixing the liquid A and the liquid B was applied onto the transparent gas barrier film. After the alkoxysilane was gelled, it was immersed in a curing solution of water, aqueous ammonia and methanol, and cured for one day at room temperature. Next, the cured gel-like compound was immersed in an isopropanol solution of hexamethyldisilazane and subjected to a hydrophobic treatment. Thereafter, supercritical drying was performed to form a silica airgel layer on the glass substrate. Silica airgel is a light-transmitting porous body having a uniform ultrafine structure. The refractive index of the layer is 1.3 or less, which is lower than the refractive index of glass of about 1.5 and the refractive index of ITO film of about 1.9. After the ITO (indium tin oxide) 120 nm film was formed and patterned on the low refractive layer thus produced, the substrate with the ITO transparent electrode and the silica airgel layer was ultrasonically cleaned with isopropyl alcohol, Drying was performed with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes. Next, in the same manner as the procedure described in Sample 109 of Example 1, co-evaporation or single vapor deposition was performed to form an element, and the gas barrier film was further formed on the cathode layer under a nitrogen atmosphere. The organic EL device is sealed by bonding the same gas barrier film substrate on which the device is formed with the transparent barrier layer facing the cathode, and bonding the surrounding area of the organic EL layer with an epoxy adhesive. did.

  Furthermore, a diffusion plate (Tsunden light diffusion film D124) is placed on the light extraction side of the support substrate, and a prism sheet (3M BEF II) is placed thereon so that the prism surface faces the opposite side of the support substrate. In addition, the prisms were set so that the same prism rows were orthogonal and the prism surface was directed to the opposite side of the support substrate. Note that a double-sided adhesive tape (model number CS9621) manufactured by Nitto Denko was used for bonding the sheets. The prism sheet is a 125 μm thick PET substrate in which Δ-shaped stripes with an apex angle of 90 degrees and a pitch of 50 μm are formed of acrylic resin, and the haze value of the diffusion plate is about 87%. It was. As a result, a white light-emitting organic EL element having a structure for improving light extraction formed and sealed on the flexible support substrate was obtained.

It is a schematic diagram which shows an example of the laminated constitution of a barrier film, and its density profile. It is the schematic which shows an example of the atmospheric pressure plasma discharge processing apparatus which processes a base material. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Glass substrate 12 Glass case 15 Cathode 16 Organic EL layer 17 Transparent electrode 18 Nitrogen gas 19 Water trapping agent 201 Barrier film 202 Base material 203 Low density layer 204 Medium density layer 205 High density layer 230 Plasma discharge treatment apparatus 231 Plasma discharge treatment vessel 231 235 Roll rotation electrode 236 Square tube type fixed electrode group 240 Electric field application means 250 Gas supply means 251 Gas generator 253 Exhaust port 260 Electrode temperature adjustment means F Base material P Liquid feed pump 261 Piping 266 Nip roll 267 Guide roll 268, 269 Partition plate

Claims (9)

A supporting substrate has at least an anode, a cathode, and a plurality of light emitting layers that emit phosphorescence between the anode and the cathode, the plurality of light emitting layers have at least three phosphorescent dopants, and the resulting light is white. In an organic electroluminescence device, at least one light emitting layer is formed from the anode side, a hole transport layer containing an electron acceptor, an electron blocking layer containing an electron acceptor, a light emitting layer, and a hole blocking layer containing an electron donor. An organic electrolayer which is laminated in the order of an electron transport layer containing an electron donor and which constitutes each layer is composed of a material satisfying the following formulas (1-1) to (2-3). Luminescence element.
(1-1) Ea ^{A / HTL} > Ea ^HTL
(1-2) Ea ^{A / EBL} > Ea ^EBL
(1-3) Ea ^EM > Ea ^EBL
(2-1) Ip ^{D / ETL} <Ip ^ETL
(2-2) Ip ^{D / HBL} <Ip ^HBL
(2-3) Ip ^EM <Ip ^HBL
However, each term in the above formula represents the electron affinity and Ip represents the ionization potential in the material forming each layer. In addition, the values of the respective terms all represent absolute values, HTL is a material for forming a hole transport layer, ETL is a material for forming an electron transport layer, A / HTL is an electron acceptor in the hole transport layer, A / EBL is an electron acceptor in the electron blocking layer, D / HBL is an electron donor in the hole blocking layer, D / ETL is an electron donor in the electron transport layer, HBL is a material forming the hole blocking layer, EBL is an electron The material for forming the blocking layer, EM, indicates the respective values in the host compound in the light emitting layer. The organic electroluminescence device according to claim 1, wherein materials other than at least the acceptor of the hole transport layer containing the electron acceptor and the electron blocking layer containing the electron acceptor are different. 3. The organic electroluminescence device according to claim 1, wherein materials other than at least the donor of the electron transport layer containing the electron donor and the hole blocking layer containing the electron donor are different. The organic electroluminescence device according to claim 1, wherein at least one light emitting layer is adjacent to the electron blocking layer and the hole blocking layer. The hole transport layer containing the electron acceptor and the electron blocking layer are adjacent to each other, or the electron transport layer containing the electron donor and the hole blocking layer are adjacent to each other. The organic electroluminescent element of any one of these. In the organic electroluminescent element according to any one of claims 1 to 5, each layer constituting the element has a glass transition temperature (Tg) of 100 ° C or higher of at least 80% by mass or more of all materials contained in each layer. An organic electroluminescent element characterized by being a material having The organic electroluminescent element according to claim 1, wherein the plurality of light emitting layers are formed of light emitting layers of three colors of red, green, and blue. Different light-emitting layers in closest proximity respectively to the anode and the cathode, the thickness including the light emitting layer, the organic electroluminescence device according to claim 7, wherein 5~30nm der Rukoto. It is an organic electroluminescent display using the organic electroluminescent element of Claim 7 or 8, Comprising: Light emission from the said organic electroluminescent element is white light, A blue filter, a green filter, and a red filter are used for this white light. through it, blue light, green light, organic electroluminescence display you characterized in that to obtain a red light.