JPWO2015147073A1 - ORGANIC ELECTROLUMINESCENT ELEMENT AND LIGHTING DEVICE - Google Patents

Abstract

Provided are an organic EL element and an illuminating device in which the chromaticity of a light emission color is reduced over time and variations in chromaticity are reduced. The light-transmitting first electrode layer 20, the second electrode layer 50 serving as a counter electrode, and a plurality of organic compound layers including the light-emitting layer 33, have an emission spectrum peak in a wavelength region of 580 nm or less. A plurality of light emitting units 30A, 30B stacked in tandem, and a base 10 that supports the first electrode layer 20, the second electrode layer 50, and the plurality of light emitting units 30A, 30B, and the light emitting units 30A, 30B. A light emitting surface 110a from which light emitted from the light emitting unit 30A is taken out and adjacent to the first electrode layer 20 or between the light emitting layer 33 of the light emitting unit 30A and the light emitting surface 110a. , 30B, an organic EL element 1 containing a quantum dot material 80 that converts the wavelength of light emitted from the light emitting element 30B, and an illumination device including the organic EL element 1 as a light source.

Description

  The present invention relates to an organic electroluminescence element and a lighting device.

  Organic light-emitting elements (hereinafter also referred to as “organic EL elements”) using organic electroluminescence (EL) are thin film-type complete devices capable of emitting light at a low voltage of several volts to several tens of volts. It is a solid element and has many excellent features such as high brightness, high luminous efficiency, thinness, and light weight. Therefore, in recent years, it has been attracting attention as a backlight for various displays, a display board such as a signboard or an emergency light, and a surface light emitter such as an illumination light source.

  One type of light-emitting device that uses such an organic EL element is a white illumination device in which a light source color is whitened. Usually, a white lighting device includes a plurality of light emitting units that emit organic light having an organic EL element, and a green light emitting unit and a red light emitting unit or a yellow light emitting unit are combined with a blue light emitting unit to produce a white light source color. The color temperature of the light source color is generally required to achieve 5000K or higher. Therefore, in the white lighting device, it is necessary to realize an appropriate light emission ratio between the green light emitting unit, the red light emitting unit or the yellow light emitting unit, and the blue light emitting unit so that light emission at a high color temperature can be realized. .

  However, a blue light emitting material used for an organic EL element that develops blue color has characteristics that are easily deteriorated as compared with a light emitting material that develops other colors. Therefore, when the light emission ratio of the blue light emitting unit is increased, the driving life of the white light emitting device greatly depends on the light emitting life of the organic EL element that develops blue color, and the high color temperature is maintained for a long time. There is a problem that it is difficult to make it. On the other hand, if the white light emission ratio is reduced by reducing the light emission ratio of the green light emission unit, the red light emission unit, or the yellow light emission unit, the light emission by the light emission unit with the reduced ratio becomes unstable, and the light emission luminance varies between lots of manufactured products. In addition, the variation in chromaticity increases, so it is difficult to use in practice. In addition, since the light emission life is greatly different between the organic EL element that develops blue color and the organic EL element that develops other colors, the color of the light source color when driving the white lighting device. There is also a problem that the degree of variation occurs with time.

  Therefore, a technique has been proposed in which quantum dots made of an inorganic compound having excellent stability are used in combination as a light emitting material in an organic EL element. For example, Patent Literature 1 discloses that in a device (205) that emits light in an output spectrum, at least one host element that emits light in a first spectrum, and a second that is different from the first spectrum. An active electroluminescence (EL) layer (216) composed of dopant elements that emit light in the spectrum, and a transparent layer (208) that at least partially transmits light emitted from the active EL layer (216). And a luminescent material (230) that converts the spectrum of light emitted from the active EL layer (216) and passed through the transparent layer (208), the luminescent material (230) being the output Device emitting light in the output spectrum, characterized by generating a spectrum Disclosed, wherein the luminescent material (230), it is described that a quantum dot structure.

  Patent Document 2 discloses an organic electroluminescent device having a pair of electrodes and at least two organic functional layers including a light emitting layer on a substrate, the light emitting layer comprising a host compound and a phosphorescent light emitting dopant. An organic electroluminescent device is disclosed in which the light emitting layer or its adjacent layer contains quantum dots.

JP 2006-190682 A International Publication No. 2013/157494

  According to the technique disclosed in Patent Document 1, a device that emits light in the output spectrum includes quantum dots as a luminescent material, thereby converting the spectrum of light emitted from the active EL layer. It is possible to obtain a white spectral light output. Moreover, according to the technique disclosed in Patent Document 2, an organic electroluminescence device having high emission efficiency and a long life can be provided by selecting a host compound, a phosphorescent light emitting dopant, and quantum dots of the light emitting layer.

  However, in the techniques disclosed in Patent Document 1 and Patent Document 2, the influence due to the drive life of the organic EL element that develops blue color still appears greatly. For this reason, the chromaticity of the luminescent color is likely to change over time, and it is not easy to maintain the luminescent color of the lighting device at a high color temperature for a long period of time. In addition, as disclosed in Patent Document 2, in the case of an apparatus configuration including a single light emitting unit, a precise concentration is required to realize a light emission color of a predetermined chromaticity by a host compound and a phosphorescent light emitting dopant. Control is required. In addition, when the concentrations of the host compound and the phosphorescent light emitting dopant cause in-plane variations with respect to the light emitting surface, it is easy to express the effect on the chromaticity of the emitted color. Productivity to achieve is not always good. For this reason, there is a need for a technique for suppressing the chromaticity variation of the emission color over time and the chromaticity variation, which can be applied to a white illumination device including an organic EL element.

  Accordingly, an object of the present invention is to provide an organic EL element and a lighting device in which the chromaticity of the emitted color is reduced over time and the chromaticity variation is reduced.

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

(1) A light transmitting first electrode layer, a second electrode layer serving as a counter electrode of the first electrode layer, and a plurality of organic compound layers including a light emitting layer, and emitting light in a wavelength region of 580 nm or less. A plurality of light emitting units having a spectral peak and stacked in tandem between the first electrode layer and the second electrode layer; the first electrode layer; the second electrode layer; And an organic electroluminescence device comprising a substrate that supports the unit, wherein the organic electroluminescence device has a light emitting surface from which light emitted from the plurality of light emitting units is extracted, and is adjacent to the first electrode layer. A quantum dot material that converts the wavelength of light emitted from the light emitting unit between the light emitting layer of the light emitting unit or the light emitting layer of the light emitting unit and the light emitting surface is contained. The organic electroluminescence element according to.
(2) The organic light-emitting element according to (1), wherein the plurality of light-emitting units have an emission spectrum peak in a wavelength region of a wavelength of 430 nm to 495 nm.
(3) The organic electroluminescent element according to (1) or (2), wherein the quantum dot material has a peak of an emission spectrum in a wavelength region of a wavelength of 480 nm or more.
(4) The organic electroluminescent element according to any one of (1) to (3), wherein the quantum dot material has an emission spectrum peak in a wavelength region of a wavelength of 480 nm to 700 nm.
(5) The organic electroluminescence device according to any one of (1) to (4), wherein a color temperature of light extracted from the light emitting surface is 5000 K or more.
(6) The quantum dot material is at least one substance selected from the group consisting of Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, and CdO. The organic electroluminescent element according to any one of (1) to (5), wherein
(7) An illumination device comprising the organic electroluminescence element according to any one of (1) to (6) as a light source.

  According to the present invention, it is possible to provide an organic EL element and a lighting device in which a change in chromaticity of a light emission color with time and a variation in chromaticity are reduced. For example, even if a light emitting layer is formed using vapor deposition, although it has a large area, it has a feature that there is little in-plane variation in the chromaticity of the emitted color, and variation in chromaticity between lots of manufactured products. It is possible to provide a long-life organic EL element that can maintain a high color temperature of 5000 K or more over a long period of time, and a white lighting device including the same.

It is sectional drawing which shows typically an example of the organic EL element which concerns on this embodiment. It is sectional drawing which shows typically an example of the organic EL element which concerns on this embodiment.

  Hereinafter, an organic EL element and a lighting device according to an embodiment of the present invention will be described in detail.

  FIG. 1 is a cross-sectional view schematically showing an example of the layer configuration of the organic EL element according to this embodiment.

[Organic EL device]
As shown in FIG. 1, the organic EL element 1 according to the present embodiment mainly includes a base material 10, an anode layer (first electrode layer) 20, a plurality of light emitting units 30A and 30B, and a cathode layer (first electrode). 2 electrode layers) 50. The plurality of light emitting units 30 </ b> A and 30 </ b> B include an anode layer (first electrode layer) 20 formed on the substrate 10 and a cathode layer that is a counter electrode that forms a pair of electrodes with the anode layer (first electrode layer) 20. An intermediate connector layer 40 is formed between the plurality of light emitting units 30A and 30B so as to be sandwiched between the light emitting units 30A and 30B. Thus, the organic EL element 1 according to the present embodiment has a stack type element structure in which a plurality of light emitting units 30A and 30B are stacked in a tandem shape.

  The base material 10 supports and fixes the anode layer 20, the plurality of light emitting units 30 </ b> A and 30 </ b> B, the intermediate connector layer 40, and the cathode layer 50. In the organic EL element 1 according to this embodiment, as shown in FIG. 1, the base material 10 is a laminated layer including an anode layer 20, a plurality of light emitting units 30 </ b> A and 30 </ b> B, an intermediate connector layer 40, and a cathode layer 50. The structure includes a hard coat layer 11 and a barrier layer 13 together with a layer of the support 12 that supports the structure. Thus, the base material 10 can be comprised by the multiple layer which consists of the support body 12 and the other functional layer formed on the support body 12. FIG. The anode layer 20, the plurality of light emitting units 30A and 30B, the intermediate connector layer 40, and the cathode layer 50 supported by the base material 10 are covered with an adhesive layer 60 made of an adhesive. And the sealing member 70 is bonded by the side facing the base material 10 through this adhesion layer 60.

  Each of the plurality of light emitting units 30A and 30B has a layer configuration including a plurality of organic compound layers, and includes at least a light emitting layer containing an organic light emitting material that emits light such as fluorescence or phosphorescence. The light emitting units 30A and 30B include, for example, a hole injection layer 31, a hole transport layer 32, a light emitting layer 33, an electron transport layer 34, an electron injection layer 35, and the like as shown in FIG. In each light emitting unit 30A, 30B, when a predetermined voltage is applied between the anode 20 and the cathode 50, holes are injected into each light emitting layer 33 from the anode layer 20 side, and from the cathode layer 50 side. Are injected with electrons. In the organic layer 33, the injected holes and electrons are recombined to form an excited state, and light is emitted when the excited state transitions to the ground state.

  The organic EL element 1 has on its outermost surface a light emitting surface from which light emitted from the plurality of light emitting units 30A and 30B is taken out. The light extraction method can be either bottom emission or top emission. Therefore, for example, as shown in FIG. 1, the light emitting surface 110a is provided on one main surface (lowermost surface) of the organic EL element 1 with the light-transmitting anode layer 20 interposed therebetween. Alternatively, when the cathode layer 50 is an electrode layer having optical transparency, the cathode layer 50 is provided on the other main surface (uppermost surface) of the organic EL element 1 with the cathode layer 50 interposed therebetween. In this way, the light emitted from each of the light emitting units 30A and 30B stacked in a tandem shape is extracted from the light emitting surface 110a through the light-transmitting electrode layer and used as a light source or the like of the lighting device.

  The organic EL element 1 according to the present embodiment is configured such that light emitted from each of the plurality of light emitting units 30A and 30B is in a wavelength region on the shorter wavelength side than the green wavelength region. Further, in the organic EL element 1, between the light emitting layer 33 of the light emitting unit 30A adjacent to the first electrode layer 20 and the light emitting surface 110a, a quantum dot material that converts the wavelength of light emitted from the plurality of light emitting units 30A and 30B. 80 is included. In the organic EL element 1, the light emission in the wavelength region on the short wavelength side emitted from the plurality of light emitting units 30A and 30B is thus down-converted to the long wavelength side by the quantum dot material 80, thereby emitting light. The variation of the chromaticity of the color over time and the variation in chromaticity are reduced, and white light with high luminance and high color temperature is generated.

[Light emitting unit]
The light emitting units 30A and 30B are not limited to the two stacked configurations shown in FIG. 1, and may be any number of two or more. Specifically, it is preferably 2 or more and 10 or less, and more preferably 2 or more and 3 or less. That is, for example, the following configuration is preferable as the stacked configuration of the organic EL element 1.
(1) Anode layer / first light emitting unit / intermediate connector layer / second light emitting unit / cathode layer (2) anode layer / first light emitting unit / first intermediate connector layer / second light emitting unit / second intermediate connector layer / Third light emitting unit / cathode layer By providing two or more light emitting units in this manner, light can be emitted with a desired luminance even at a low current density, and the emission life of blue light emission can be prolonged. On the other hand, if the number of light emitting units is 10 or less, preferably 3 or less, it is possible to avoid deterioration of the production efficiency of the organic EL element.

  The plurality of light emitting units 30A and 30B each have a peak of an emission spectrum in a wavelength region of 580 nm or less so as to emit light in a wavelength region shorter than the green wavelength region. By causing the plurality of light emitting units 30A and 30B to emit light in such a spectrum, the light emission luminance of light emission on the short wavelength side by the blue light emitting material which is easily deteriorated can be maintained for a long time. In addition, by converting the wavelength of high-luminance light emission with the quantum dot material 80, it becomes possible to stably extract light having a high color temperature. In the present specification, the phrase “a light emitting unit has an emission spectrum peak in the wavelength region” means that all the peaks of the emission spectrum of the light emitting layer 33 included in a certain light emitting unit are within a predetermined wavelength region. To do. The same applies to a set of a plurality of types of quantum dot materials 80.

  The plurality of light emitting units 30A and 30B preferably have an emission spectrum peak in a wavelength region of 430 nm to 580 nm in which the emission color exhibits blue to green, and have a wavelength of 430 nm to 495 nm in which the emission color exhibits purple to blue. It is more preferable to have an emission spectrum peak in the wavelength region. When the plurality of light emitting units 30A and 30B emit light having an emission spectrum peak in such a wavelength region, it is possible to avoid the deterioration of the blue light emitting material due to the light in the ultraviolet region, and the quantum dot material. It is possible to easily adjust the light emission intensity and chromaticity of the complementary color by 80.

  The light emission luminance, light emission spectrum, and chromaticity of light emitted by each light emitting unit 30A, 30B mainly include a plurality of organic compound layers including a light emitting layer 33 (a hole injection layer 31, a hole transport layer 32, a light emitting layer 33, an electron transport). The layer 34, the electron injection layer 35, etc.) can be adjusted based on the layer configuration and layer composition. These layer configurations and layer compositions will be described later.

[Quantum dot materials]
The quantum dot material 80 is a particulate material having a predetermined particle diameter that is made of a semiconductor crystal and exhibits a quantum dot effect. The energy level E of a quantum dot is generally represented by the following formula (I) where the Planck constant is “h”, the effective mass of electrons is “m”, and the radius of the fine particles is “R”.
E∝h ² / mR ² (I)
As shown in the formula (I), the band gap of the quantum dot increases in proportion to “R ⁻² ”, and the quantum dot effect is obtained. Thus, the band gap value of a quantum dot can be controlled by controlling and defining the particle diameter of the quantum dot. That is, by controlling and defining the particle size of the quantum dot particles, it is possible to provide diversity that is not found in ordinary molecules. For this reason, it is possible to condense electrons and holes in the quantum dots and recombine them by exciting them with light or applying a voltage to the organic EL elements including the quantum dots. It can be converted and emitted. In the organic EL element 1, a particulate material that exhibits such a quantum dot effect is used as the quantum dot material 80.

  In the organic EL element 1 according to the present embodiment, the quantum dot material 80 is applied so as to wavelength-convert light emitted from the plurality of light emitting units 30A and 30B to the long wavelength side. That is, a quantum dot material 80 having an absorption spectrum in the wavelength region of light emission from each light emitting unit 30A, 30B is used to excite the quantum dot material 80, and the quantum dot material 80 emits light in the wavelength region on the short wavelength side. Is emitted with the emission spectrum converted to the longer wavelength side, and the visible light intensity on the longer wavelength side is increased. Thus, white light or high color temperature light is extracted from the light emitting surface 110a by mixing the emission color of the emission from each of the light emitting units 30A and 30B and the emission color of the emission from the quantum dot material 80. Yes.

  The quantum dot material 80 preferably has an emission spectrum peak in a wavelength region of 480 nm or more so that light is emitted in a wavelength region longer than the green wavelength region, and emits light in a green to red wavelength region. As described above, it is more preferable to have an emission spectrum peak in a wavelength region of 480 nm to 700 nm. When the quantum dot material 80 that emits light in such a spectrum is used, the chromaticity of light extracted from the light emitting surface 110a can be appropriately adjusted based on the adjustment of the addition amount of the quantum dot material 80.

  The quantum dot material 80 can be contained in the light emitting layer 33 of the light emitting unit 30A adjacent to the anode layer 20 or other layers provided between the light emitting layer 33 of the light emitting unit 30A and the light emitting surface 110a. The layer containing the quantum dot material 80 may be either a single layer or a plurality of layers, and may be either an external layer or an internal layer of the light emitting unit.

  As a layer outside the light emitting unit containing the quantum dot material 80, for example, as shown in FIG. 1, a functional layer (such as a barrier layer 13 constituting the substrate 10) provided in the organic EL element can be cited. It may be the hard coat layer 11 constituting the substrate 10, the support 12 constituting the substrate 10, or the like. Moreover, the quantum dot material 80 can be contained in the film affixed on the outermost surface of the organic EL element 1, and it is not prevented from containing in the light-scattering resin layer which has light-scattering property. If the quantum dot material 80 is contained in a layer outside the light emitting unit as described above, it is possible to avoid the charge injected from each electrode layer from being taken away by the quantum dot material 80. Further, by adjusting the addition amount and particle diameter of only the quantum dot material 80, it becomes possible to obtain desired light emission luminance and chromaticity while maintaining the composition prescription of the organic compound layer.

  As a layer inside the light emitting unit containing the quantum dot material 80, for example, as shown in FIG. 2, the light emitting layer 33 of the light emitting unit 30A, the hole transport layer 32 adjacent to the light emitting layer 33 of the light emitting unit 30A, etc. Is mentioned. Further, the hole injection layer 31 of the light emitting unit 30A, a hole blocking layer (not shown), or the like may be used. When the quantum dot material 80 is contained in the inner layer of the light emitting unit in this way, the quantum dot material 80 can be mixed with the coating liquid during the coating formation of the organic compound layer, and the number of man-hours can be reduced and the quantum dots can be reduced. It becomes easy to apply the dot material 80.

  In addition, when the cathode layer 50 is an electrode layer having light transmittance, the quantum dot material 80 includes the light emitting layer 33 of the light emitting unit 30B adjacent to the cathode layer 50 or the light emitting layer 33 of the light emitting unit 30B. It can be contained in another layer provided between the light emitting surface provided on the other main surface (uppermost surface) of the organic EL element 1. Specifically, the adhesive layer 60 and other functional layers provided in the organic EL element, for example, a barrier layer constituting the sealing member 70, and the like can be given.

  Note that the quantum dot material 80 is formed by, for example, spin coating, casting, ink jet, printing, slot die, spray coating, dip coating when forming the organic compound layer or the substrate 10 of these light emitting units. By adopting a known wet film forming method such as a method, a blade method, and a slit coating method, and mixing with the coating solution, the light emitting unit can be contained in an outer layer or an inner layer. In addition, a monomolecular film of the quantum dot material 80 can be produced and transferred to these layers and their interfaces.

  The particle diameter of the quantum dot material 80 is set to an appropriate value according to a desired emission spectrum, but is preferably 1 nm to 20 nm, more preferably 1 nm to 10 nm. Specifically, the particle diameter of the quantum dot material 80 is about 3.0 nm to 20 nm when the emission color is red, and about 1.5 nm to 10 nm when the emission color is green. . In addition, the range of such a particle diameter should just be what the average particle diameter of the quantum dot material 80 is contained in these ranges.

  The average particle diameter of the quantum dot material 80 can be measured using a known measurement method. For example, particles of the quantum dot material 80 are observed with a transmission electron microscope (TEM), and a number average particle size is obtained from the particle size distribution, or a particle size measuring device using a dynamic light scattering method, such as “ZETASIZER”. There are a method of measuring using “Nano Series Nano-ZS” (manufactured by Malvern), a method of deriving a particle size distribution from a spectrum obtained by a small-angle X-ray scattering method using a particle size distribution simulation calculation of quantum dots, and the like. Can be mentioned.

  The addition amount of the quantum dot material 80 is preferably 0.01 part by mass to 50 parts by mass, and 0.05 part by mass to 25 parts by mass with respect to 100 parts by mass of all constituent substances of the layer to be added. Is more preferable, and 0.1 to 20 parts by mass is particularly preferable. If the addition amount of the quantum dot material 80 is 0.01 parts by mass or more, the light emission of the dopant material of the light emitting layer 33 is set to an appropriate wavelength, and the absorption energy of the quantum dot material 80 is adjusted to significantly increase the quantum dot effect. It can be obtained and it is easy to stabilize the brightness and chromaticity of the extracted light. Moreover, if the addition amount of the quantum dot material 80 is 50 parts by mass or less, the inter-particle distance of the dispersed quantum dot material 80 can be sufficiently ensured, so that the quantum dot effect by the added quantum dot material 80 is ensured. Can be demonstrated.

Examples of substances constituting the quantum dot material 80 include simple elements of Group 14 elements of the periodic table such as carbon, silicon, germanium, and tin, simple elements of Group 15 elements of the periodic table such as phosphorus (black phosphorus), selenium, and tellurium. A periodic group 16 element such as silicon carbide (SiC), a compound comprising a plurality of periodic table 14 elements such as silicon carbide (SiC), tin oxide (IV) (SnO ₂ ), tin sulfide (II, IV) (Sn ( II), Sn (IV) S ₃ ), tin sulfide (IV) (SnS ₂ ), tin sulfide (II) (SnS), tin selenide (II) (SnSe), tin telluride (II) (SnTe), Compounds of periodic table group 14 elements and periodic table group 16 elements such as lead (II) sulfide (PbS), lead selenide (II) (PbSe), lead telluride (II) (PbTe), boron nitride ( BN), boron phosphide (BP), boron arsenide (B s), aluminum nitride (AlN), aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), antimonide Compound of periodic table group 13 element and periodic table group 15 element such as gallium (GaSb), indium nitride (InN), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb) (or the like) III-V compound semiconductor), aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), gallium oxide (Ga ₂ O ₃ ), gallium sulfide (Ga ₂ S ₃ ), gallium selenide (Ga ₂ Se _3), telluride gallium _(Ga 2 _Te 3), oxide Lee Indium _{(In 2 O} 3), indium sulfide _{(In 2 S} 3), indium selenide _(In 2 _Se 3), periodic table Group 13 element and Periodic Table Group 16 such as a telluride, indium _(In 2 Te ₃₎ A compound with an element, thallium chloride (I) (TlCl), thallium bromide (I) (TlBr), thallium iodide (I) (TlI), etc. Compound, zinc oxide (ZnO), zinc sulfide (ZnS), zinc selenide (ZnSe), zinc telluride (ZnTe), cadmium oxide (CdO), cadmium sulfide (CdS), cadmium selenide (CdSe), cadmium telluride (CdTe), mercury oxide (HgO), mercury sulfide (HgS), mercury selenide (HgSe), mercury telluride (HgTe), etc. Compound of Group 6 element (or II-VI compound semiconductor), arsenic oxide _{(III) (As 2 O} 3), arsenic sulfide _{(III) (As 2 S} 3), selenium arsenic (III) _(As 2 Se ₃ ), arsenic telluride (III) (As ₂ Te ₃ ), antimony (III) oxide (Sb ₂ O ₃ ), antimony (III) sulfide (Sb ₂ S ₃ ), antimony selenide (III) (Sb ₂ Se ₃ ), antimony telluride (III) (Sb ₂ Te ₃ ), bismuth (III) oxide (Bi ₂ O ₃ ), bismuth sulfide (III) (Bi ₂ S ₃ ), bismuth selenide (III) (Bi ₂ Se _3), bismuth telluride _{(III) (Bi 2 Te 3} ) compounds of the periodic table group 15 element and periodic table group 16 element such as copper oxide (I) _(Cu 2 O), copper selenide (I Compound with _(Cu 2 Se) periodic table group 11 element and Periodic Table Group 16 element such as, copper chloride (I) (CuCl), copper bromide (I) (CuBr), copper iodide (I) ( Compounds of Group 11 elements of the periodic table such as CuI), silver chloride (AgCl), silver bromide (AgBr), and Group 17 elements of the periodic table such as nickel oxide (II) (NiO) And compounds of Group 16 elements of the periodic table, compounds of Group 9 elements of the periodic table such as cobalt (II) oxide (CoO), cobalt sulfide (II) (CoS), and Group 16 elements of the periodic table, Compounds of Group 8 elements of the periodic table such as iron (Fe ₃ O ₄ ) and iron sulfide (II) (FeS) and Group 16 elements of the periodic table, Group 7 of the periodic table such as manganese oxide (II) (MnO) Compound of element and group 16 element of periodic table, molybdenum sulfide (IV) (MoS ₂ ), oxidation Compounds of Group 6 elements of the periodic table such as tungsten (IV) (WO ₂ ) and Group 16 elements of the periodic table, vanadium (II) oxide (VO), vanadium oxide (IV) (VO ₂ ), tantalum oxide (V ) (Ta ₂ O ₅ ) and other periodic table group 5 elements and periodic table group 16 elements, titanium oxide (TiO ₂ , Ti ₂ O ₅ , Ti ₂ O ₃ , Ti ₅ O _9, etc.) Compound of periodic table group 4 element and periodic table group 16 element, compound of periodic table group 2 element such as magnesium sulfide (MgS), magnesium selenide (MgSe), etc., periodic table group 16 element, cadmium oxide (II) chromium (III) (CdCr ₂ O ₄ ), cadmium selenide (II) chromium (III) (CdCr ₂ Se ₄ ), copper sulfide (II) chromium (III) (CuCr ₂ S ₄ ), mercury selenide (I ) Chromium _{(III) (HgCr 2 Se 4} ) chalcogen spinels such as, barium titanate (BaTiO ₃₎ can be mentioned.

Among the substances constituting the quantum dot material 80, among these, SnS ₂ , SnS, SnSe, SnTe, PbS, PbSe, PbTe and other compounds of periodic table group 14 elements and periodic table group 16 elements, GaN, III-V group compound semiconductors such as GaP, GaAs, GaSb, InN, InP, InAs, InSb, Ga ₂ O ₃ , Ga ₂ S ₃ , Ga ₂ Se ₃ , Ga ₂ Te ₃ , In ₂ O ₃ , In ₂ S ₃ , In ₂ Se ₃ , In ₂ Te ₃ periodic table group 13 element and periodic table group 16 element compound, ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgO, HgS, HgSe, II-VI group compound semiconductor such as _{HgTe, As 2 O 3, As} 2 S 3, As 2 Se 3, As 2 Te 3, Sb 2 O 3 Sb ₂ S _3, and _{Sb 2 Se 3, Sb 2 Te} 3, Bi 2 O 3, Bi 2 S 3, Bi 2 Se 3, Bi 2 Te 3 Periodic Table Group 15 element and Periodic Table Group 16 element such as A compound of the periodic table group 2 element and the periodic table group 16 element such as MgS, MgSe, etc. is preferable, and Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, CdO, Ga ₂ O ₃ , Ga ₂ S ₃ , and In ₂ O ₃ are more preferable. Since these substances do not contain negative elements, they are suitable in terms of avoiding environmental pollution and toxicity to living organisms. Further, since a pure spectrum can be stably obtained in the visible light region, it is also suitable for adjusting chromaticity. Among these, ZnO or ZnS is a preferable material from the viewpoints of luminous efficiency, high refractive index, and safety.

  One of these substances constituting the quantum dot material 80 may be used alone, or two or more thereof may be used in combination. That is, one kind of quantum dot material 80 particles may be contained within the above-mentioned emission spectrum or particle diameter range, and two or more kinds of quantum dot material 80 particles may be contained. In addition to these substances, the quantum dot material 80 may be doped with a small amount of various elements as impurities as necessary. By doping a small amount of various elements, the light emission characteristics of the quantum dot material 80 can be greatly improved.

  The quantum dot material 80 may be a particle having a core / shell type structure. That is, the quantum dot material 80 can be comprised by the core part which has a quantum dot effect, and the shell part which consists of an inert inorganic substance or an organic ligand. Moreover, a core part and a shell part may be comprised with a different substance, and a gradient structure (gradient structure) may be formed between a core part and a shell part. When such a core / shell type quantum dot material 80 is used, aggregation of the quantum dot material 80 can be suppressed and dispersibility can be improved. And it becomes easy to adjust light emission luminance and chromaticity, and stable light emission characteristics can be obtained. The thickness of the shell part is preferably 0.1 nm to 10 nm, more preferably 0.1 nm to 5 nm.

  The quantum dot material 80 may be further surface-modified particles. The surface-modified particles can be obtained by attaching a surface modifier to the surface of such a single particle of the quantum dot material 80 or the surface of the shell portion of the core / shell type quantum dot material 80. When the surface-modified quantum dot material 80 is used, the compatibility of the surface-modified quantum dot material 80 can be improved and can be favorably dispersed in the coating liquid that forms the layer of the organic EL element 1. Alternatively, when the quantum dot material 80 is manufactured, the quantum dot material 80 having a desired particle diameter can be easily grown.

  Examples of the surface modifier include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, tripropylphosphine, tributylphosphine, trihexylphosphine, and trioctylphosphine. Trioxyphosphines, polyoxyethylene n-octylphenyl ether, polyoxyethylene alkylphenyl ethers such as polyoxyethylene n-nonylphenyl ether, tri (n-hexyl) amine, tri (n-octyl) amine , Tertiary amines such as tri (n-decyl) amine, tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine Organic phosphorus compounds such as xoxide, tridecylphosphine oxide, polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate, and organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine and quinoline , Hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine and other amino alkanes, dibutyl sulfide and other dialkyl sulfides, dimethyl sulfoxide and dibutyl sulfoxide and other dialkyl sulfoxides, Organic sulfur compounds such as sulfur-containing aromatic compounds such as thiophene, higher fatty acids such as palmitic acid, stearic acid and oleic acid, alcohols and sorbitan fatty acid esters Ethers and, and fatty acid-modified polyesters, or a tertiary amine modified polyurethanes and polyethylene imines, and the like. Among these, as the surface modifier, a substance that coordinates to and stabilizes the quantum dot fine particles in the high-temperature liquid phase is preferable from the viewpoint of production. Specifically, trialkylphosphines, organophosphorus compounds, amino acids are preferable. Alkanes, tertiary amines, organic nitrogen compounds, dialkyl sulfides, dialkyl sulfoxides, organic sulfur compounds, higher fatty acids and alcohols are preferred.

  The quantum dot material 80 can be manufactured by a known method. Specifically, for example, molecular beam epitaxy, CVD, liquid phase synthesis, or the like can be used. As the liquid phase synthesis method, for example, reverse micelles of raw material aqueous solutions are used in nonpolar organic solvents such as alkanes such as n-heptane, n-octane and isooctane, or aromatic hydrocarbons such as benzene, toluene and xylene. The reverse micelle method in which the crystals are formed and grown in the reverse micelle phase, the hot soap method in which a thermally decomposable raw material is injected into a high-temperature liquid-phase organic medium to grow the crystals, and the solution reaction in which the crystals are grown by acid-base reaction at low temperatures Law.

[Base material]
As the base material 10, the substrate (support 12) supporting the element structure of the organic EL element alone, or other functional layers (barrier layer, hard coat layer, light scattering resin layer, etc.) together with the substrate (support 12) ) Can be used.

  There are no particular limitations on the type of the support 12 such as glass or plastic, and it may be transparent or opaque. In the case where light is extracted from the support side, the support is preferably transparent. Examples of the transparent support preferably used include glass, quartz, and a transparent resin film. A particularly preferable support is a resin film capable of giving flexibility to the organic EL element. Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyester such as modified polyester, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate (TAC), cellulose acetate butyrate, cellulose acetate pro Cellulose esters such as pionate (CAP), cellulose acetate phthalate, cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, polystyrene, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, Polyether ketone, polyimide, polyether sulfone (PES), polyphenol Ren sulfide, polysulfone, polyethersulfone, polyvinyl chloride, polyvinylidene chloride, polyetherimide, polyetherketoneimide, polyetheretherketone, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, arton Cycloolefin resins such as (trade name, manufactured by JSR) or Apel (trade name, manufactured by Mitsui Chemicals) can be used.

  The surface of the support 12 may be subjected to a surface treatment such as imparting easy adhesion to ensure wettability and adhesion of the coating solution. Examples of the surface treatment include surface activation treatment such as corona discharge treatment, flame treatment, ultraviolet treatment, high frequency treatment, glow discharge treatment, active plasma treatment, and laser treatment. Also, an easy-adhesion layer may be formed by applying polyester, polyamide, polyurethane, vinyl copolymer, butadiene copolymer, acrylic copolymer, vinylidene copolymer, epoxy copolymer, etc. Good.

The substrate 10 may be one in which a barrier layer or a hard coat layer is formed of an inorganic material, an organic material, or a hybrid thereof. Specifically, the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by a method according to JIS K 7129-1992 is 1 × 10 ⁻³ g / (m ² · 24 h) or less barrier layer or oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ⁻³ ml / m ² · 24 h · atm or less, water vapor permeability (25 ± 0 A barrier layer having a temperature of 0.5 ° C. and a relative humidity (90 ± 2)% RH) of 1 × 10 ⁻³ g / (m ² · 24 h) or less is preferable.

  The material for forming the barrier layer may be any material that has a function of suppressing intrusion of moisture, oxygen, or the like that degrades the element. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used. Furthermore, in order to improve the fragility of the barrier layer, the barrier layer preferably has a laminated structure. The laminated structure can be formed, for example, by alternately laminating inorganic layers and organic layers a plurality of times. Examples of the material for forming the hard coat layer include silicone resins, epoxy resins, vinyl ester resins, acrylic resins, allyl ester resins, and the like, and materials obtained by combining these resin materials and inorganic materials. It is preferable to use a resin material that is ultraviolet-cured, heat-cured, or electron-beam cured for compounding.

  These functional layers include titanium oxide, zinc oxide, aluminum oxide (alumina), zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, magnesium oxide, barium oxide, indium oxide for adjusting light scattering properties and refractive index. Metal oxide particles such as tin oxide and lead oxide, and inorganic compounds such as silicon dioxide, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate It is good also as a layer containing particle | grains and polymer particles, such as a silicone resin, a fluororesin, an acrylic resin, a styrene resin, a melamine resin.

  The barrier layer can be formed by, for example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, atmospheric pressure plasma polymerization, plasma CVD. Method, laser CVD method, thermal CVD method, coating method and the like. Examples of the method for forming the hard coat layer include a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, and an ink jet method.

[Anode layer]
Examples of the anode layer (anode) include an electrode having any of a metal, an alloy, an electrically conductive compound, and a mixture thereof having a high work function (4 eV or more). 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) that can form a transparent conductive film can be used.

  The anode layer may be formed as a thin film using a method such as vapor deposition or sputtering, and then a pattern having a desired shape may be formed by a photolithography method, or pattern accuracy is not required. May be formed by a method such as vapor deposition or sputtering through a mask having a desired shape (about 100 μm or more). Moreover, when using the substance which can be apply | coated like an organic electroconductivity compound, wet application methods, such as a printing system and a coating system, can also be used.

  The film thickness of the anode layer can be set appropriately according to the electrode substance used as a material, but is about 10 to 1000 nm, preferably 10 to 200 nm. When light emission is extracted from the anode side, it is desirable that the transmittance be greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less.

[Cathode layer]
Examples of the cathode layer (cathode) include electrodes having any of a metal, an alloy, an electrically conductive compound, and a mixture thereof having a small work function (4 eV or less). Such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture. , Indium, lithium / aluminum mixtures, rare earth metals and the like.

  The cathode layer can be formed as a thin film using these electrode materials by a method such as vapor deposition or sputtering. Note that when light emission is extracted from the cathode, the cathode is a light-transmitting layer. A light-transmitting cathode can be formed into a transparent or translucent cathode by forming a cathode with a film thickness of 1 to 20 nm and then covering a conductive transparent material known as an anode electrode material on the cathode. it can.

  The film thickness of the cathode can be appropriately determined according to the electrode substance used as a material, but is about 5 to 10 μm, preferably 50 to 200 nm. The sheet resistance of the cathode is preferably several hundred Ω / □ or less.

[Light emitting unit]
Hereinafter, the layer configuration and each component of each light emitting unit will be described. The specific layer configuration of the light emitting unit may be, for example, the following stacked configuration in order from the layer on the anode side.
(1) (Anode side) Light emitting layer / electron transport layer (cathode side)
(2) (Anode side) Hole transport layer / light emitting layer / electron transport layer (cathode side)
(3) (Anode side) Hole transport layer / light emitting layer / hole blocking layer / electron transport layer (cathode side)
(4) (Anode side) Hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer (cathode side)
(5) (Anode side) Hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer (cathode side)
(6) (Anode side) Hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer (cathode side)

(Light emitting layer)
The light emitting layer is a layer containing an organic light emitting material that emits light by combining electrons and holes injected from the electrode, and the light emitting portion is adjacent to the light emitting layer even in the light emitting layer. It may be an interface with. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. The light emitting layer includes a host material and a dopant material. Each light emitting layer may contain a plurality of host materials and dopant materials. 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.

  As the host material, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable, and a compound of less than 0.01 is more preferable. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer. The host material may be a conventionally known low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). A compound that has a hole transporting ability and an electron transporting ability, prevents an increase in emission wavelength, and has a high Tg (glass transition temperature) is preferable.

  Specific examples of the host material include, for example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, and 2002. No. -334786, No. 2002-8860, No. 2002-334787, No. 2002-15871, No. 2002-334788, No. 2002-43056, No. 2002-334789, No. 2002. No. 75645, No. 2002-338579, No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227 issue No. 2002-231453, No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-260861, No. 2002-280183. , 2002-299060, 2002-302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  As the dopant material, a phosphorescent dopant material or a fluorescent dopant material can be used. The phosphorescent dopant material and the fluorescent dopant material may be included in the same light emitting layer. A phosphorescent dopant material is a compound in which light emission from an excited triplet is observed. Specifically, it is a compound that emits phosphorescence at room temperature (25 ° C.), and a phosphorescence quantum yield of 0.01 at 25 ° C. It is defined as the above compound. The phosphorescent quantum yield of the phosphorescent dopant material is preferably 0.1 or more. The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant material to be used may be any material that achieves the phosphorescence quantum yield in any solvent.

  There are two types of light emission principles of the phosphorescent dopant material. One is the recombination of carriers on the host material to which carriers are transported to generate an excited state of the host material, and this energy is transferred to the phosphorescent dopant material. Energy transfer type to obtain light emission from the phosphorescent dopant material, and the other is a carrier trap in which the phosphorescent dopant material becomes a carrier trap, and carrier recombination occurs on the phosphorescent dopant material, and light emission from the phosphorescent dopant material is obtained. In any case, the condition is that the excited state energy of the phosphorescent dopant material is lower than the excited state energy of the host material.

  The phosphorescent dopant material can be appropriately selected from known materials used for the light emitting layer of the organic EL element. The phosphorescent dopant material 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, a platinum compound (platinum complex compound), or a rare earth complex. Of these, iridium compounds are most preferred.

  Specific examples of the compound used as the phosphorescent dopant material include the compounds described in JP2011-222385A, but the present invention is not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, etc.

  The fluorescent dopant material can be appropriately selected from known materials used for the light emitting layer of the organic EL element. Specifically, for example, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. System dyes, polythiophene dyes, rare earth complex phosphors, and the like. The fluorescent dopant material may be a compound that exhibits delayed fluorescence.

  The thickness of the light emitting layer is about 2 nm to 5 μm, preferably 5 nm to 200 nm, more preferably 10 nm to 150 nm. When the thickness of the light emitting layer is about 5 nm or more, it is easy to ensure the uniformity of the formed light emitting layer. Further, when the thickness of the light emitting layer is about 200 nm or less, it is not necessary to apply an excessively high voltage for driving, and the chromaticity of light emission is easily stabilized.

  The dopant material preferably has an emission spectrum peak in a wavelength region of 580 nm or less, more preferably has an emission spectrum peak in a wavelength region of 430 nm or more and 580 nm or less where the emission color is blue to green. It is more preferable that the emission spectrum has a peak in a wavelength region of 430 nm to 495 nm in which the color is purple to blue. By including a dopant material having an emission spectrum peak in such a wavelength region in the light emitting layer of each light emitting unit, each light emitting unit can emit light with chromaticity corresponding to the wavelength region. The dopant material may be contained at a uniform concentration with respect to the thickness direction of the light emitting layer, but may be contained so as to have a concentration distribution.

(Hole injection layer)
The hole injection layer is a layer provided between the electrode and the organic compound layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its forefront of industrialization (November 30, 1998, NTS Corporation) Issue) ”, Chapter 2, Chapter 2,“ Electrode Materials ”(pages 123-166). The hole injection layer can be interposed, for example, between the anode and the light emitting layer or between the anode and the hole transport layer.

  The details of the hole injection layer are described in, for example, JP-A-9-45479, JP-A-9-260062, and JP-A-8-288069. Are triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives. , An aniline copolymer, a polyarylalkane derivative or a conductive polymer, preferably a polythiophene derivative, a polyaniline derivative, or a polypyrrole derivative, more preferably a polythiophene. It is a conductor. The thickness of the hole injection layer is not particularly limited, but is about 0.1 nm to 5 μm, preferably 0.1 nm to 100 nm, more preferably 1 nm to 100 nm, and particularly preferably 10 nm to 60 nm.

(Electron injection layer)
The electron injection layer is a layer provided between the electrode and the organic compound layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (issued by NTS, November 30, 1998) ) ", Chapter 2, Chapter 2," Electrode Materials "(pp. 123-166). The electron injection layer can be interposed, for example, between the cathode and the light emitting layer, or between the cathode and the electron transport layer.

  Details of the electron injection layer are described in, for example, JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specifically, strontium, aluminum and the like are representative. A metal buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, an oxide buffer layer typified by aluminum oxide, and the like.

  The thickness of the electron injection layer is not particularly limited, but is about 0.1 nm to 5 μm, preferably 0.1 to 100 nm, more preferably 0.5 to 10 nm, and particularly preferably 0.5 to 4 nm. is there.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transporting material applicable to the hole transporting layer is a material having either hole injection or transport or electron barrier properties, and the same compound as that used for the hole injecting layer is used. In addition, porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds, especially aromatic tertiary amine compounds can be used.

  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 ' Di (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, as well as those described in US Pat. No. 5,061,569 Having four condensed aromatic rings in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 08688 are linked in a starburst type ( MTDATA) etc. 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. Inorganic compounds such as type-SiC can also be used as a hole injecting material and a hole transporting material, and also disclosed in JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Appl.Phys., 95, 5773 (2004), Japanese Patent Application Laid-Open No. 11-251067, J. Huang et.al. Physics Letters, 80 (2002), p. 139), and a hole transport material that has a so-called p-type semiconductor property, as described in JP-T-2003-519432.

  The thickness of the hole transport layer is not particularly limited, but is about 5 nm to 5 μm, preferably 5 to 200 nm.

(Electron transport layer)
The electron transport layer is made of an electron transport material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer.

The electron transport material applicable to the electron transport layer may have a function of transmitting electrons injected from the cathode to the light emitting layer. For example, a fluorene derivative, a carbazole derivative, an azacarbazole derivative, an oxadiazole derivative , Thiadiazole derivatives, trizole derivatives, silole derivatives, pyridine derivatives, pyrimidine derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, 8-quinolinol derivatives, etc. Conventionally known electron transport material compounds such as In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), 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), etc., 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. In addition, inorganic compounds such as n-type-Si and n-type-SiC can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having a terminal substituted with an alkyl group or a sulfonic acid group can be used as the electron transport material. Alternatively, an electron transport layer with high n property doped with impurities as a guest material can be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  The thickness of the electron transport layer is not particularly limited, but is about 5 nm to 5 μm, preferably 5 to 200 nm.

(Blocking layer: hole blocking layer, electron blocking layer)
Examples of the blocking layer include, for example, JP-A Nos. 11-204258 and 11-204359, and “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998)”. There are hole blocking layers described on pages.

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

  Examples of the hole blocking material applicable to the hole blocking layer include, for example, carbazole derivatives, carboline derivatives, diazacarbazole derivatives (herein, diazacarbazole derivatives constitute carboline rings) listed as host compounds. And any one of the carbon atoms is replaced by a nitrogen atom).

  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 blocks electrons while transporting holes. Thus, the probability of recombination of electrons and holes can be improved.

  As an electron blocking material applicable to the electron blocking layer, for example, the same species as the hole transporting material can be used.

  The film thicknesses of the hole blocking layer and the electron transport layer are preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

  In addition, the above organic compound layer is made of the above-described materials, for example, vacuum deposition method, spin coating method, casting method, ink jet method, printing method, slot die method, spray coating method, Langmuir-Blodgett method (LB method), The thin film can be formed by a known method such as a dip coating method, a blade method, and a slit coating method.

[Intermediate connector layer]
The intermediate connector layer 40 is formed so as to be sandwiched between the light emitting units 32A and 32B. When the number of light emitting units is N (N is an integer of 2 or more), N−1 pieces are provided. The intermediate connector layer 40 is in a state in which a metal material is hardly formed on a part of the fine region thereof, a so-called pinhole is formed, a net is formed in the in-plane direction, or an island shape is formed on the main surface. It may be formed so as to be distributed in spots.

  Moreover, the intermediate | middle connector layer 40 may be coat | covered with the organic compound layer which comprises light emitting unit 32A, 32B which adjoins. That is, the side of the intermediate connector layer 40 or the vicinity of the outer edge is covered with the organic compound layer, while the organic compound layer of one light-emitting unit is in close contact with the organic compound layer of the other light-emitting unit. It can be laminated in a state where it is buried in the compound layer. Thus, by covering the side surface of the intermediate connector layer 40 with the organic compound layer, it is possible to prevent a leakage current from occurring between the intermediate connector layer 40 and each electrode layer, and to stabilize light emission. become able to.

Examples of materials applicable to the intermediate connector layer 40 include calcium, magnesium, lithium, sodium, potassium, cesium, rubidium, barium, strontium, silver, aluminum, zinc, niobium, zirconium, tin, tantalum, vanadium, molybdenum, Metals such as rhenium, tungsten, mercury, gallium, indium, cadmium, boron, hafnium, lanthanum, and titanium, alloys thereof, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO Can be mentioned.

  The intermediate connector layer 40 is light transmissive, and the visible light transmittance is preferably 60% or more, more preferably 80% or more. The transmittance may be measured according to a method defined in JIS R3106.

  The film thickness of the intermediate connector layer 40 is preferably 0.6 nm to 5 nm, more preferably 0.8 nm to 3 nm, and still more preferably 0.8 nm to 2 nm. When the film thickness of the intermediate connector layer 40 is 0.6 nm or more, it becomes easy to ensure the performance stability of the organic EL element 1, and in particular, it is possible to reduce fluctuations in the initial performance immediately after the organic EL element 1 is manufactured. It becomes. On the other hand, if the film thickness of the intermediate connector layer 40 is 5 nm or less, absorption of light transmitted through the intermediate connector layer 40 is suppressed, so that the light emission efficiency of the organic EL element 1 can be increased. Further, it is possible to reduce storage stability and drive stability deterioration. The film thickness of the intermediate connector layer 40 means an average film thickness obtained by dividing the film forming mass per unit area of the intermediate connector layer 40 by the material density. Therefore, the film thickness of the intermediate connector layer 40 does not need to be uniform.

  In each of the light emitting units 32A and 32B arranged so as to sandwich the intermediate connector layer 40, the layer adjacent to the intermediate connector layer 40 has a function of easily transferring charges to and from the intermediate connector layer 40. Preferably it is. Specifically, the layer adjacent to the intermediate connector layer 40 includes, for example, a charge transporting organic material having a high charge transporting property and an inorganic material or an organometallic complex capable of oxidizing or reducing the charge transporting organic material, Alternatively, it is preferably formed as a mixed layer doped with this charge transporting organic material and an inorganic material or an organometallic complex capable of forming a charge transfer complex.

  The intermediate connector layer 40 can be formed by a known method such as resistance heating evaporation, electron beam evaporation, ion plating, or ion beam sputtering.

[Sealing member]
Specific examples of the sealing member 70 include a glass plate, a polymer plate, a polymer film, a metal plate, and a metal 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. As the polymer plate and polymer film, ethylene tetrafluoroethyl copolymer (ETFE), high density polyethylene (HDPE), expanded polypropylene (OPP), polystyrene (PS), polymethyl methacrylate (PMMA), expanded nylon (ONy), Examples thereof include thermoplastic resin films such as polyethylene terephthalate (PET), polycarbonate (PC), polyimide, and polyethersulfone (PES). The thermoplastic resin film may be a multilayer film formed by co-extrusion of plural types, a multilayer film bonded by changing the stretching angle, or the like. Examples of the metal plate and metal film 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. It is done.

  The sealing member 70 may have a barrier layer formed on the surface. Examples of the barrier layer include a metal vapor deposition film and a metal foil. Examples of the metal deposition film include thin film handbooks p879 to p901 (Japan Society for the Promotion of Science), vacuum technology handbooks p502 to p509, p612 and p810 (Nikkan Kogyo Shimbun), vacuum handbook revised editions p132 to p134 (ULVAC Japan Vacuum Technology K.K. Those described in K). As metal foil, metal foil, such as aluminum, copper, nickel, and alloy foil, such as stainless steel and an aluminum alloy, can be used, for example. The barrier layer may have a protective layer formed on the surface. As a protective layer, the thermoplastic resin film whose melt flow rate of JISK7210 regulation is 5-20 g / 10min is preferable, and the thermoplastic resin film of 6-15 g / 10min or less is more preferable.

  As an adhesive for laminating the sealing member 70, a photocurable or thermosetting adhesive having a reactive vinyl group such as an acrylic acid oligomer or a methacrylic acid oligomer, 2-cyanoacrylate, or the like Moisture-curing adhesives, epoxy-based thermosetting or chemical-curing (two-component) adhesives, hot-melt polyamide-based, polyester-based, polyolefin-based adhesives, and cationic-curing type adhesives An ultraviolet curable epoxy resin adhesive is mentioned. The adhesive may be added with a filler. Examples of the filler include soda glass, alkali-free glass, silica, metal oxides such as titanium dioxide, antimony oxide, titania, alumina, zirconia, and tungsten oxide. The adhesive is preferably one that can be adhesively cured from room temperature to 80 ° C., and can be applied by a coating method such as roll coating, spin coating, screen printing, spray coating, or the like.

[Light extraction]
The light emitting surface 110a can be provided with means for improving the efficiency of extracting light generated in the light emitting layer 33. Means for improving the light extraction efficiency include, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435). A method of improving efficiency by giving light condensing properties to a material (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), a substrate, A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the light emitters (Japanese Patent Laid-Open No. 62-172691), and a lower refractive index than the base material between the base material and the light emitter. A method of introducing a flat layer having a structure (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer, and a light emitting layer (including between the substrate and the outside world) 11-283951) and the like.

  Further, the light emitting surface 110a can be provided with a light collecting means. For example, by processing to provide a microlens array structure or combining with a so-called condensing sheet, the light is condensed in a specific direction, for example, in the front direction with respect to the light emitting surface of the element. Can be increased. As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 μm to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable. As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used. As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used. Moreover, in order to control the light emission angle from an element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

[Usage]
The above organic EL element can be used as a display device, a display, and various light emission sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Although it is not limited to this, it can be effectively used for a backlight of a liquid crystal display device combined with a color filter and a light source for illumination. In particular, the lighting device is suitable as a kind of lamp such as home lighting, interior lighting, and exposure light source.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples of the present invention, but the present invention is not limited thereto.

  As an embodiment of the present invention, an organic EL device comprising two light emitting units between an anode layer (first electrode layer) and a cathode layer (second electrode layer), and a substrate containing a quantum dot material The chromaticity variation over time and the chromaticity variation were evaluated.

[Preparation of quantum dot material]
First, quantum dot material A and quantum dot material B were synthesized by the following procedure.

<< Quantum dot material A >>
Indium myristate 0.1 mmol, stearic acid 0.1 mmol, trimethylsilylphosphine 0.1 mmol, dodecanethiol 0.1 mmol, and undecylenic acid zinc 0.1 mmol were put into a three-necked flask together with octadecene 8 mL and refluxed under a nitrogen atmosphere. However, by heating at 300 ° C. for 1 hour, core / shell type quantum dot particles “InP / ZnS” (quantum dot material A) having a core part of InP and a shell part of ZnS were obtained.

  Subsequently, the quantum dot material A was observed for morphology using a transmission electron microscope. As a result, a core / shell structure in which the core portion InP was covered with the shell portion ZnS was confirmed. Moreover, it was confirmed that the particle diameter of the core part of quantum dot material A is 2.1 nm-3.8 nm, and the particle diameter distribution of a core part is 6%-40% on a number basis. In addition, "JEM-2100" (made by JEOL Ltd.) was used as a transmission electron microscope.

  Further, the quantum dot material A was subjected to emission spectrum analysis and absorption spectrum analysis. As a result, it was confirmed that the absorption spectrum appeared in a wide range, the peak of the emission spectrum was included in the range of 430 nm to 720 nm, and the half width of the emission spectrum was 35 nm to 90 nm. Moreover, it was confirmed that the luminous efficiency reaches 70.9%. In addition, a fluorescence spectrophotometer “FluoroMax-4” (manufactured by JOBIN YVON) is used for emission spectrum analysis, and a spectrophotometer “U-4100” (manufactured by Hitachi High-Technologies Corporation) is used for absorption spectrum analysis. Each was used by dispersing quantum dot material A in dehydrated toluene.

<< Quantum dot material B >>
A solution containing about 70 mg of quantum dot material A was dried under vacuum and then dispersed in toluene. Next, 5 mL of the obtained dispersion was heated to 40 ° C., and 0.5 mL of perhydropolysilazane (“AQUAMICA NN120-10”, non-catalytic type, manufactured by AZ Electronic Materials Co., Ltd.) was added while keeping the temperature and stirring. The mixture was added, and the reaction was continued with stirring at about 40 ° C. for 1 hour. And after drying the obtained particle | grains by vacuuming, the quantum dot material B which has the coating | coated with which some polysilazane was silica-modified was obtained by performing excimer laser irradiation.

[Preparation of substrate]
Next, a substrate (optical film) containing a quantum dot material was prepared by the following procedure.

≪Optical film 1≫
The quantum dot material A was sieved into a quantum dot material A (red component) that emits red light and a quantum dot material A (green component) that emits green light. Then, after 0.75 mg of red component and 4.12 mg of green component are dispersed in toluene, a PMMA resin solution containing polymethyl methacrylate (PMMA) particles having a particle size of 0.8 μm to 10 μm is added. Then, a quantum dot material A coating solution in which the red component was 1% by mass and the green component was 1% by mass was prepared.

  The obtained quantum dot material A coating solution is applied to one side of a 125 μm thick polyester film “KDL86WA” (manufactured by Teijin DuPont Films Ltd.) with easy adhesion on both sides so that the film thickness after drying becomes 100 μm. And it was made to dry at 60 degreeC for 3 minute (s), and while containing a red component and a green component, the light-scattering resin layer which has light-scattering property was formed.

  Subsequently, perhydropolysilazane (“AQUAMICA NP110”, manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in toluene so as to be 10% by mass to prepare a barrier layer coating solution. Then, the obtained barrier layer coating solution was applied to the other surface of the polyester film using a wireless bar so that the film thickness after drying was 300 nm, and was 1 in an atmosphere of 85 ° C. and humidity 55% RH. After being held and dried for 25 minutes, it is dehumidified by holding for 10 minutes in an atmosphere of 25 ° C. and humidity 10% RH (dew point temperature −8 ° C.) to form a barrier layer, which has a light scattering property. Thus, an optical film 1 having a light scattering resin layer and a barrier layer having a single layer structure was obtained.

≪Optical film 2≫
The quantum dot material B was sieved into a quantum dot material B (red component) that emits red light and a quantum dot material B (green component) that emits green light. Then, after 0.75 mg of the red component was dispersed in toluene, a UV curable resin solution was added to prepare a quantum dot material B coating solution (red component coating solution) in which the red component was 1% by mass. Similarly, after dispersing 4.12 mg of the green component in toluene, a UV curable resin solution is added, and the quantum dot material B coating solution (green component coating solution) in which the green component becomes 1% by mass is obtained. Prepared. As the UV curable resin solution, a UV curable resin “Unidic V-4025” (manufactured by DIC Corporation) and a photopolymerization initiator “Irgacure 184” (manufactured by BASF Japan) are mixed in a solid mass ratio (resin : Initiator) was used to prepare a solution prepared to be 95: 5.

The obtained red component coating solution was applied on one side of a 125 μm thick polyester film “KDL86WA” (manufactured by Teijin DuPont Films Ltd.) with easy adhesion processing on both sides so that the film thickness after drying would be 50 μm, After drying at 60 ° C. for 3 minutes, the red component coating solution was cured to form a hard coat layer containing the red component. The curing reaction was performed using a high-pressure mercury lamp and an irradiation amount of 0.5 J / cm ² in an air atmosphere. And the green component coating liquid was apply | coated and hardened on the upper surface of the formed hard coat layer containing the red component so that it might become the same conditions, and the hard coat layer containing a green component was formed.

  Subsequently, in the same manner as in the optical film 1, a barrier layer coating solution is applied to the other surface of the polyester film, dried and dehumidified to form a barrier layer, and a red / green two-layer hard coat layer and a barrier layer are formed. The optical film 2 which has this was obtained.

≪Optical film 3≫
The quantum dot material A was sieved into a quantum dot material A (red component) that emits red light and a quantum dot material A (green component) that emits green light. Then, a solution in which 0.75 mg of red component and 4.12 mg of green component are dissolved in toluene so that perhydropolysilazane (“Aquamica NP110”, manufactured by AZ Electronic Materials Co., Ltd.) is 10 mass%. The quantum dot material A coating liquid in which the red component was 1% by mass and the green component was 1% by mass was prepared.

A UV curable resin solution similar to that of the optical film 2 is coated on one side with a 125 μm thick polyester film “KDL86WA” (manufactured by Teijin DuPont Films) so that the film thickness after drying is 50 μm. After coating and drying at 60 ° C. for 3 minutes, the UV curable resin solution was cured to form a hard coat layer. The curing reaction was performed using a high-pressure mercury lamp and an irradiation amount of 0.5 J / cm ² in an air atmosphere.

  Subsequently, the quantum dot material A coating solution was applied to the other surface of the polyester film using a wireless bar so that the film thickness after drying was 300 nm, and the coating solution was 1 in an atmosphere of 85 ° C. and humidity 55% RH. After holding and drying for 25 minutes, dehumidifying by holding for 10 minutes in an atmosphere of 25 ° C. and humidity 10% RH (dew point temperature −8 ° C.) to form a barrier layer containing a red component and a green component, An optical film 3 having a hard coat layer and a red / green single layer barrier layer was obtained.

[Production of Organic EL Element 101]
Next, the organic EL element 101 was produced according to the following procedure.

  First, indium tin oxide (ITO) was deposited on the barrier layer of the prepared optical film 1 by patterning so as to have a film thickness of 110 nm to form an anode layer. Next, the optical film 1 on which the anode layer was formed was immersed in isopropyl alcohol, subjected to ultrasonic cleaning, dried with dry nitrogen gas, and then cleaned with UV and ozone for 5 minutes.

Subsequently, the cleaned optical film 1 is fixed to a substrate holder of a vacuum deposition apparatus, and each of the molybdenum or tungsten resistance heating deposition crucibles is filled with an appropriate amount of the material of the organic compound layer of the light emitting unit. did. And after depressurizing the vapor deposition chamber of the vacuum vapor deposition apparatus to a vacuum degree of 1 × 10 ⁻⁴ Pa, HAT-CN represented by the following formula was vapor-deposited to a film thickness of 20 nm to form a hole injection layer. .

  Next, Compound 1 represented by the following formula (glass transition point (Tg) = 140 ° C.) was deposited to a film thickness of 50 nm to form a hole transport layer.

  Subsequently, the compound 2 (Tg = 189 ° C.) represented by the following formula and the compound 3 were vapor-deposited so that the compound 2 was 95% by volume, the compound 3 was 5% by volume, and the film thickness was 30 nm. A light emitting layer that turns blue was formed.

  Next, the compound represented by the following formula (ET-100) and LiF were vapor-deposited so that ET-100 was 86% by volume, LiF was 14% by volume, and the film thickness was 20 nm to form an electron transport layer. It was set as the 1st light emission unit.

  Subsequently, ET-100 and LiF were vapor-deposited on the upper surface of the formed first light emitting unit so that ET-100 was 98% by volume, LiF was 2% by volume, and the film thickness was 10 nm. An intermediate connector layer was formed by vapor deposition to a thickness of 10 nm.

  Then, a second light emitting unit was formed on the upper surface of the formed intermediate connector layer in the same manner as the first light emitting unit. That is, a hole injection layer and a hole transport layer are sequentially formed, and the compound 2 and the compound 3 are vapor-deposited so that the compound 2 is 95% by volume, the compound 3 is 5% by volume, and the film thickness is 30 nm. A light emitting layer having a blue color was formed, and an electron transport layer was formed to obtain a second light emitting unit.

  Then, Al was vapor-deposited so that it might become a film thickness of 150 nm on the upper surface of the formed 2nd light emission unit, and the cathode layer was formed. Next, a glass sealing member in which an epoxy-based photocurable adhesive “Luxtrac LC0629B” (manufactured by Toagosei Co., Ltd.) is applied in advance to the edge is formed so as to cover the non-light emitting surface on the formed cathode layer side. After making it closely_contact | adhere with a material, sealing was performed by irradiating UV and the organic EL element 101 was obtained. Sealing was performed 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 obtained organic EL element 101 had an emission spectrum peak at a wavelength of 480 nm.

[Production of Organic EL Element 102]
The organic EL element 102 was produced in the same procedure as the organic EL element 101 except that the content of the quantum dot material in the optical film 1 was changed to 0.8% by mass.

[Production of Organic EL Element 103]
The organic EL element 103 was produced in the same procedure as the organic EL element 101 except that the content of the quantum dot material in the optical film 1 was changed to 0.5% by mass.

[Production of Organic EL Element 104]
An organic EL element 104 was produced in the same procedure as the organic EL element 101 except that the optical film 2 was used instead of the optical film 1.

[Production of Organic EL Element 105]
An organic EL element 105 was produced in the same procedure as the organic EL element 104 except that the content of the quantum dot material in the optical film 2 was changed to 0.8% by mass.

[Production of Organic EL Element 106]
The organic EL element 106 was produced in the same procedure as the organic EL element 104 except that the content of the quantum dot material in the optical film 2 was changed to 0.5% by mass.

[Production of Organic EL Element 107]
An organic EL element 107 was produced in the same procedure as the organic EL element 101 except that the optical film 3 was used instead of the optical film 1.

[Production of Organic EL Element 108]
The organic EL element 108 was produced in the same procedure as the organic EL element 107 except that the content of the quantum dot material in the optical film 3 was changed to 0.8 mass%.

[Production of Organic EL Element 109]
An organic EL element 109 was produced in the same procedure as the organic EL element 107 except that the content of the quantum dot material in the optical film 3 was changed to 0.5% by mass.

[Production of Organic EL Element 110]
The organic EL element 110 was produced in the same procedure as the organic EL element 107 except that the content of the quantum dot material in the optical film 3 was changed to 0.3% by mass.

[Production of Organic EL Element 201]
Next, the organic EL element 201 was produced according to the following procedure.

First, a UV cured resin solution similar to that of the optical film 2 is dried on one side of a 125 μm-thick polyester film “KDL86WA” (manufactured by Teijin DuPont Films Ltd.) that is easily bonded on both sides to a thickness of 50 μm. After coating at 60 ° C. for 3 minutes, the UV curable resin solution was cured to form a hard coat layer. The curing reaction was performed using a high-pressure mercury lamp and an irradiation amount of 0.5 J / cm ² in an air atmosphere.

  Subsequently, perhydropolysilazane (“AQUAMICA NP110”, manufactured by AZ Electronic Materials Co., Ltd.) was dissolved in toluene so as to be 10% by mass to prepare a barrier layer coating solution. Then, the obtained barrier layer coating solution was applied to the other surface of the polyester film using a wireless bar so that the film thickness after drying was 300 nm, and was 1 in an atmosphere of 85 ° C. and humidity 55% RH. After holding and drying for a minute, the film was held for 10 minutes in an atmosphere of 25 ° C. and a humidity of 10% RH (dew point temperature −8 ° C.) for 10 minutes to form a barrier layer, whereby an optical film 4 was obtained.

  Next, on the barrier layer of the prepared optical film 4, a first light emitting unit whose emission color is blue is formed in the same procedure as the organic EL element 101, and further, on the upper surface of the formed first light emitting unit, An intermediate connector layer was formed, and a hole injection layer and a hole transport layer were sequentially formed on the upper surface of the formed intermediate connector layer.

  Subsequently, the compound 4 (Tg = 143 ° C.), the compound 5 and the compound 6 represented by the following formula are mixed into the compound 4 having 79% by volume, the compound 5 having 20% by volume, the compound 6 having 1% by volume, and a film thickness of 30 nm. Evaporation was performed to form a light emitting layer in which the emission color was a mixed color of green and red.

  Subsequently, the compound (ET-100) and LiF were vapor-deposited so that ET-100 might be 86 volume%, LiF might be 14 volume%, and the film thickness might be 50 nm, and an electron carrying layer was formed, and it was set as the 2nd light emission unit. .

  Then, a cathode layer is formed by vapor-depositing Al so as to have a film thickness of 150 nm on the upper surface of the formed second light emitting unit, sealing is performed in the same procedure as the organic EL element 101, and the organic EL element 201 is formed. Got.

[Production of Organic EL Element 202]
The organic EL element 202 was produced in the same procedure as the organic EL element 201 except that the film thickness of the electron transport layer in the second light emitting unit was changed to 20 nm.

[Production of Organic EL Element 203]
The organic EL element 203 was produced in the same procedure as the organic EL element 201 except that the film thickness of the electron transport layer in the second light emitting unit was changed to 10 nm.

[Performance evaluation of organic EL elements]
Next, performance evaluation was performed about the produced organic EL elements 101-110 and 201-203.

(Evaluation of color temperature)
Each organic EL element is allowed to emit light at a constant current density of ^2.5 mA / cm ² at room temperature (within a range of about 23 to 25 ° C.), and the light emission luminance at the start of light emission is measured. The temperature (K) was determined. For the measurement, a spectral radiance meter “CS-2000” (manufactured by Konica Minolta Sensing) was used. The results of color temperature measurement are shown in Table 1.

(Evaluation of luminous lifetime)
Each organic EL element is allowed to emit light at a constant current density of 5000 cd / m ² at room temperature, and the light emission luminance is measured. The time until the light emission luminance is reduced by 30% from the initial value is the emission lifetime. As measured. The results are shown in Table 1.

(Evaluation of chromaticity variation)
Along with the above-mentioned measurement of the light emission lifetime, the chromaticity of the light emission color of each organic EL element is measured at the start of light emission and when the light emission luminance is reduced by 30% from the initial value, and the chromaticity variation is calculated. did. The chromaticity variation was evaluated according to the following criteria on the CIE-XYZ color system chromaticity diagram based on the displacement of coordinates (ΔExy) with respect to the white point.
ΔExy: less than 0.005 ◎
ΔExy: 0.005 or more and less than 0.02 ○
ΔExy: 0.02 or more and less than 0.04 Δ
ΔExy: 0.04 or more ×

(Evaluation of chromaticity variation)
Ten organic EL elements were prepared in the same procedure, and the chromaticity of the emitted color was measured, and the chromaticity variation (variation between lots) between the produced organic EL elements was evaluated. did. Note that the chromaticity variation is the displacement (ΔExy) of the coordinates of the organic EL element showing the maximum displacement with respect to the coordinates of the average value of the produced organic EL elements of the same type on the CIE-XYZ color system chromaticity diagram. Based on the following criteria, the evaluation was made.
ΔExy: less than 0.005 ◎
ΔExy: 0.005 or more and less than 0.02 ○
ΔExy: 0.02 or more and less than 0.05 Δ
ΔExy: 0.05 or more ×

  The results of the above performance evaluation are shown in Table 1 together with the configuration of each organic EL element. In addition, the addition amount of the quantum dot material in Table 1 has shown the fraction (mass%) with respect to 100 mass parts of all the structural substances of a content layer. The light emission lifetime is a relative value when the organic EL element 201 is 100.

  As shown in Table 1, in the organic EL elements 101 to 110 according to the examples of the present invention, regardless of the layer of the quantum dot material 80, by adjusting the addition amount of the quantum dot material, It was confirmed that light emission at a high color temperature was achieved, and the color temperature of light extracted from the light emitting surface 110a could be 5000K or higher.

  In the organic EL elements 201 to 203 (organic EL elements 201 to 203 according to the comparative example) configured by combining light emitting units that emit light with different emission colors without using the quantum dot material 80, the electron transport layer is made thin and high color. If an attempt is made to achieve light emission at a temperature, the light emission lifetime decreases and it becomes difficult to stabilize the chromaticity, whereas in the organic EL elements 101 to 110 according to the examples, the light emission lifetime is prolonged and the light emission color is increased. It was confirmed that fluctuations in chromaticity over time and variations in chromaticity between organic EL elements were also reduced.

  Therefore, the present invention relates to an organic EL element in which the color temperature of the extracted light is 5000 K or more, and a lighting device including such an organic EL element as a light source. This is suitable for reducing variations in chromaticity.

1 Organic EL element 10 Base material 20 Anode layer (first electrode layer)
30A, 30B Light emitting unit 31 Hole injection layer 32 Hole transport layer 33 Light emitting layer 34 Electron transport layer 35 Electron injection layer 40 Intermediate connector layer 50 Cathode layer (second electrode layer)
60 Adhesive layer 70 Sealing member 80 Quantum dot material 110a Light emitting surface

Claims (7)

A first electrode layer having optical transparency;
A second electrode layer as a counter electrode of the first electrode layer;
A plurality of organic compound layers including a light emitting layer, having an emission spectrum peak in a wavelength region of 580 nm or less, and stacked in tandem between the first electrode layer and the second electrode layer Light emitting unit,
A base material that supports the first electrode layer, the second electrode layer, and the plurality of light emitting units;
An organic electroluminescence device comprising:
The organic electroluminescence element has a light emitting surface from which light emitted from the plurality of light emitting units is extracted,
A light emitting layer of the light emitting unit adjacent to the first electrode layer, or a quantum dot material that converts the wavelength of light emitted from the light emitting unit between the light emitting layer and the light emitting surface of the light emitting unit is contained. An organic electroluminescence device characterized by that.   2. The organic electroluminescence device according to claim 1, wherein the plurality of light emitting units have a peak of an emission spectrum in a wavelength region of a wavelength of 430 nm or more and 495 nm or less.   The organic electroluminescent element according to claim 1, wherein the quantum dot material has an emission spectrum peak in a wavelength region of 480 nm or more.   4. The organic electroluminescence element according to claim 1, wherein the quantum dot material has a peak of an emission spectrum in a wavelength region of a wavelength of 480 nm or more and 700 nm or less.   5. The organic electroluminescence element according to claim 1, wherein the color temperature of light extracted from the light emitting surface is 5000 K or more. The quantum dot material is composed of at least one substance selected from the group consisting of Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, and CdO. The organic electroluminescence element according to claim 1, wherein the organic electroluminescence element is characterized in that:   An illuminating device comprising the organic electroluminescent element according to any one of claims 1 to 6 as a light source.

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