JP2015099636A - Organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flexible organic electroluminescent element which is excellent in color rendering properties and durability (storage stability) to folding.SOLUTION: Disclosed is an organic electroluminescent having a light-emitting member unit constituted of a pair of electrodes which are arranged in at least positions opposite to each other on a flexible resin base material, and an organic functional layer group including a light-emitting layer held by the electrodes. On the light extraction side, a polysilazane-containing layer is provided which includes quantum dots.

Description

  The present invention relates to an organic electroluminescence device, and more particularly, to an organic electroluminescence device having excellent color rendering properties and excellent storage stability after being bent.

  Currently, as a thin light-emitting material, an organic electroluminescence element utilizing electroluminescence of an organic material (hereinafter referred to as “EL”), a so-called organic electroluminescence element (hereinafter also referred to as “organic EL element”). .) Is a thin-film type solid-state device capable of emitting light at a low voltage of about several volts to several tens of volts, and has many excellent features such as high brightness, high luminous efficiency, thinness, and light weight. For this reason, it attracts attention as a surface light emitter such as backlights of various displays, display boards such as signboards and emergency lights, and illumination light sources. In particular, a flexible organic electroluminescence element using a resin base material having a thin and light gas barrier film has attracted attention.

  Various attempts have been made to improve the light emission characteristics of organic EL elements. Recently, as one method for obtaining excellent light emission characteristics, “quantum dots” are arranged on the light extraction side of the organic EL elements. Methods have been studied, and the effect of improving the color rendering properties by supplementing the luminescent color by light emission that is photoexcited in a down-conversion manner is known.

  Quantum dots are of interest for commercial applications because of their size-tunable electronic properties. Quantum dots can be used in a wide variety of fields, for example, biolabeling, solar power generation, catalysis, biological imaging, light emitting diodes (LEDs), general spatial lighting, and electroluminescent displays. Expected.

  For example, in an optical device using quantum dots, the amount of light incident on a liquid crystal display device (LCD) is increased by irradiating the quantum dots with LED light to emit light, thereby increasing the brightness of the LCD. Has been proposed (see, for example, Patent Document 1).

However, this quantum dot is known to deteriorate when it comes into contact with oxygen, and various means for preventing the quantum dot from coming into contact with oxygen are employed. As such means, for example, a method of sealing quantum dots with a barrier film or a sealing material can be mentioned, but although oxygen blocking performance can be secured, it is necessary to perform sealing work under an N ₂ atmosphere, etc. The manufacturing equipment becomes expensive and sophisticated, and has a problem that it is inferior in versatility.

  On the other hand, a method for preventing the quantum dots from coming into contact with oxygen by coating the surface of the quantum dots with silica or glass has been proposed (see, for example, Patent Documents 2 and 3).

  However, the method of covering the quantum dots with silica or glass can obtain oxygen blocking performance, but the dispersibility in the resin is reduced due to the formation of silica aggregates of the quantum dots and the increase in the secondary particle diameter. Thus, the transparency and durability are insufficient, such as a decrease in transparency, a decrease in oxygen shielding performance due to the influence of the external environment, and a decrease in luminance.

  On the other hand, in an organic light emitting diode light therapy illumination system, a method is disclosed in which quantum dots are used as inorganic light emitters in the light emitting regions of a plurality of flexible organic EL elements (see, for example, Patent Document 4). .

  Furthermore, in a flexible organic EL device, the presence of quantum dots in the light emitting layer or its adjacent layer together with a phosphorescent light emitting dopant enables high luminous efficiency and long life, excellent color rendering, and chromaticity even at low driving voltage. Has disclosed a method for obtaining a stable white light-emitting organic EL device (see, for example, Patent Document 5).

  However, when the quantum dots are applied to a light emitting material using the quantum dots as described above, in particular, an organic EL element having a flexible resin base material, it is a flexible organic EL element. It is clear that the quantum dots placed in the layer are damaged due to stress such as tensile stress and compressive stress applied to the layer, resulting in deterioration of color rendering properties and storage stability of the organic EL element. Therefore, the response is required.

JP 2011-202148 A International Publication No. 2007/034877 Special table 2013-505347 gazette Special table 2012-514498 gazette JP2012-169460A

  This invention is made | formed in view of the said problem, The solution subject is providing the flexible organic electroluminescent element which is excellent in the color rendering property and durability (storage stability) with respect to bending.

  As a result of intensive studies in view of the above problems, the present inventor has found that an organic material including a pair of electrodes disposed at least at opposing positions on a flexible resin substrate and a light emitting layer sandwiched between the electrodes. Durability against color rendering and bending (storage stability) with an organic electroluminescence device characterized by having a light emitting member unit composed of functional layer groups and a polysilazane-containing layer containing quantum dots on the light extraction side The present inventors have found that a flexible organic electroluminescence device having excellent properties can be provided, and have reached the present invention.

  That is, the said subject of this invention is solved by the following means.

1. Organic electroluminescence having a light emitting member unit composed of a pair of electrodes disposed at least on opposing positions on a flexible resin substrate and an organic functional layer group including a light emitting layer sandwiched between the electrodes. An element,
An organic electroluminescence device comprising a polysilazane-containing layer containing quantum dots on the light extraction side.

  2. 2. The organic electroluminescent element according to claim 1, wherein the polysilazane-containing layer including the quantum dots is located in a neutral region of stress when the organic electroluminescent element receives a bending moment.

  3. 3. The organic electroluminescence element according to item 1 or 2, wherein the polysilazane-containing layer containing quantum dots is a layer containing a modified polysilazane modified product.

  4). 4. The organic electroluminescence device according to item 3, wherein the modification treatment for the polysilazane-containing layer is a modification method using vacuum ultraviolet irradiation.

  5. The polysilazane-containing layer including the quantum dots is disposed between the flexible resin base material and the light emitting member unit, according to any one of the first to fourth items, The organic electroluminescent element of description.

  6). It has a polysilazane-containing layer containing the quantum dots on the flexible resin substrate, and further, a gas barrier layer and the light emitting member unit are laminated in this order on the polysilazane-containing layer. The organic electroluminescent element according to any one of items 1 to 5 above.

7). The quantum dot is composed of at least Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, CdO, or a mixture thereof. Item 9. The organic electroluminescence device according to any one of Items 1 to 6.

  8). 8. The organic electroluminescence device according to any one of items 1 to 7, wherein the quantum dot has a core / shell structure or a gradient structure formed of at least two kinds of compounds.

  9. Any one of the first to eighth aspects, wherein the electrode disposed on the light extraction side of at least one of the pair of opposed electrodes is an electrode mainly composed of silver. The organic electroluminescent element according to claim 1.

  By the above means of the present invention, it is possible to provide a flexible organic electroluminescence device having excellent color rendering properties and durability against bending (storage stability).

  The expression mechanism / action mechanism that has achieved the above-described object effect of the present invention is not clear, but is presumed as follows.

  That is, barrier technology and stress distribution technology are required for the problem that quantum dots are easily destroyed by oxygen and external stress stress. The prior art has not found any technology that can satisfy these problems. The present inventors have found that by introducing a polysilazane-containing layer containing quantum dots, both barrier properties and stress dispersion can be achieved, and the present invention has been achieved. In particular, it has been found that the barrier property and the stress distribution are remarkably improved because the quantum dots are dispersed in the polysilazane layer, which is an inorganic polymer, because the affinity between the chemical bonding state and the elastic modulus is good.

Schematic sectional view showing an example of a typical configuration of the organic EL element of the present invention Schematic diagram for explaining the neutral region according to the present invention

  The organic electroluminescent element of the present invention is composed of a pair of electrodes disposed at least on opposing positions on a flexible resin substrate, and an organic functional layer group including a light emitting layer sandwiched between the electrodes. And a polysilazane-containing layer containing quantum dots on the light extraction side. This feature is a technical feature common to the inventions according to claims 1 to 9.

  As an embodiment of the present invention, the polysilazane-containing layer containing the quantum dots according to the present invention is neutralized in stress when the organic electroluminescence device is subjected to a bending moment, from the viewpoint that the effects intended by the present invention can be further expressed. A configuration located in the region is a desirable mode. This is because the tensile stress received on the surface side of the organic electroluminescence element and the compressive stress received on the back side are balanced when subjected to deformation due to external pressure such as bending, so that no stress is generated at all or very little stress is applied. By disposing a polysilazane-containing layer containing quantum dots in a neutral region (also referred to as the center of gravity region of elastic modulus) that does not occur, the quantum dots are not subject to particle breakage due to excessive stress (stress), An organic electroluminescence element having excellent durability can be obtained.

  In addition, the polysilazane-containing layer containing the quantum dots according to the present invention is a layer containing a modified polysilazane-modified body to form a high-quality quantum dot-containing layer excellent in stress resistance. It is desirable from the viewpoint of

  Further, it is desirable that the modification treatment for the polysilazane-containing layer is a modification method using vacuum ultraviolet irradiation because a polysilazane modified layer having high quality and high homogeneity can be stably obtained. .

  In addition, the polysilazane-containing layer including the quantum dots may be arranged between the flexible resin base material and the light emitting member unit, and the polysilazane-containing layer may be disposed in a neutral region. This is desirable in that an organic electroluminescence device excellent in light extraction efficiency and bending resistance can be obtained.

  Moreover, it has the polysilazane content layer containing the quantum dot which concerns on this invention on a flexible resin base material, and also the gas barrier layer and the said light emitting member unit are laminated | stacked in this order on the said polysilazane content layer. A configuration is preferable. When the polysilazane-containing layer contains particulate quantum dots, the surface of the layer may reflect the shape of the quantum dots, resulting in a weak uneven shape. On the polysilazane-containing layer having such an uneven surface, If the light emitting member unit is directly formed, the planarity of the organic functional layer or the like may be affected. Therefore, by forming a barrier layer on the polysilazane-containing layer in advance, the unevenness of the polysilazane-containing layer is smoothed (also called leveling). This is also desirable from the viewpoint of ensuring the flatness of the light emitting member unit provided thereon.

In addition, the quantum dot is composed of at least Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, CdO, or a mixture thereof. It is desirable from the viewpoint that the effect of can be exhibited more.

  In addition, it is desirable that the quantum dots have a core / shell structure or a gradient structure formed of at least two kinds of compounds from the viewpoint of further improving resistance to stress.

  In addition, at least one of a pair of electrodes facing each other, the electrode disposed on the light extraction side being composed of an electrode containing silver as a main component, the surface resistance is low and the light transmission property This is a desirable mode from the viewpoint that a high transparent electrode can be formed and higher light extraction efficiency can be realized.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Basic structure of organic EL element >>
The organic EL element of the present invention is composed of a pair of electrodes arranged at least on opposing positions on a flexible resin substrate, and an organic functional layer group including a light emitting layer sandwiched between the electrodes. It has a light emitting member unit and has a polysilazane-containing layer containing quantum dots on the light extraction side.

  FIG. 1 is a schematic cross-sectional view showing an example of a typical configuration of the organic EL element of the present invention.

  In the organic EL device of the present invention, the polysilazane-containing layer containing quantum dots is preferably disposed in the neutral region in the entire thickness direction constituting the organic electroluminescence device, and more preferably, the polysilazane containing quantum dots. The content layer is a configuration arranged between the flexible resin base material and the light emitting member unit, and a particularly preferable configuration has a polysilazane content layer containing quantum dots on the flexible resin base material. Further, the gas barrier layer and the light emitting member unit are laminated in this order on the polysilazane-containing layer.

  FIG. 1A shows a typical example of a particularly preferable configuration in the organic EL device of the present invention.

  In FIG. 1A, an organic EL element 1 has a polysilazane-containing layer 4 including quantum dots QD according to the present invention formed on a flexible resin substrate 2. By allowing the quantum dots QD to be dispersed in the polysilazane-containing layer 4, the quantum dots QD exhibit excellent high light emission efficiency and color rendering, and the polysilazane, which is a binder constituting the polysilazane-containing layer 4, causes the quantum dots QD. By being protected, the influence of oxygen on the quantum dots QD can be prevented. The polysilazane-containing layer according to the present invention is composed of polysilazane or a polysilazane modified body, and at least a part of the polysilazane constituting the polysilazane-containing layer is preferably modified by heat or vacuum ultraviolet rays.

  Further, a gas barrier layer 5 is formed on the polysilazane-containing layer according to the present invention. By setting it as such a structure, the fine uneven structure of the polysilazane content layer 4 surface resulting from quantum dot QD is smoothed by the gas barrier layer 5 formed on it. Such a smoothing effect is particularly remarkable when the first electrode 6 described below is formed of a silver thin film electrode or the like as a transparent electrode.

  On the smooth gas barrier layer 5 described above, a light emitting member unit U which is a main component of the organic EL element is formed. The light emitting member unit U mainly has a light transmitting first electrode 6 (transparent electrode) disposed on the flexible resin substrate 2 side (light extraction side) as one opposing electrode, a light emitting layer. And a second electrode 8 (also referred to as a counter electrode) disposed on the sealing member 9 side as the other opposing electrode. A sealing member 9 is provided on the outermost surface for the purpose of preventing these components from being affected by moisture and oxygen from the external environment.

  The configuration as shown in FIG. 1A is a preferable embodiment in that it is easy to dispose the polysilazane-containing layer 4 in the neutral region.

  Further, a back coat layer 3, for example, an antistatic layer or the like can be provided on the back side of the flexible resin substrate 2.

  FIG. 1B is a schematic cross-sectional view showing another example of the organic EL element of the present invention.

  The organic EL element 1 shown in FIG. 1B has a configuration in which the arrangement of the polysilazane-containing layer 4 and the gas barrier layer 5 is reversed with respect to the configuration shown in FIG. The gas barrier layer 5, the polysilazane-containing layer 4, and the first electrode 6 (transparent electrode) are laminated in this order.

  By providing the gas barrier layer 5 between the flexible resin substrate 2 and the polysilazane-containing layer 4 as shown in FIG. The influence of oxygen or the like on the quantum dots QD constituting the polysilazane-containing layer 4 can be further suppressed, which is further improved from the viewpoint of durability.

  However, in the configuration shown in FIG. 1B, the first electrode 6 is formed directly on the polysilazane-containing layer 4 containing the quantum dots QD having fine irregularities. In the case of an electrode, there is no problem in practical use, but the uniformity and smoothness of the first electrode are slightly lowered compared to the configuration shown in FIG.

  FIG. 1C is a schematic cross-sectional view showing another example of the organic EL element of the present invention.

  The organic EL element 1 shown in FIG. 1C has a configuration in which a polysilazane-containing layer 4 is arranged on the outermost surface on the light extraction side with respect to the configuration shown in FIG. This is one of the configurations of the organic EL element.

  However, since the polysilazane-containing layer 4 containing the quantum dots QD is located on the outermost layer, it is greatly deviated from the neutral region of stress and is subjected to the maximum tensile stress or compressive stress. Increases and is positioned on the outermost surface layer, it becomes susceptible to moisture and oxygen. Moreover, since it is located away from the light emitting layer constituting the light emitting member unit, from the viewpoint of high light emission efficiency and color rendering properties, the structure described in (a) and (b) of FIG. 1 is practically used. Although it is possible, it is a characteristic that the degree of expression of the objective effect of the present invention is slightly lowered.

[Light extraction side]
One feature of the organic EL device of the present invention is that a polysilazane-containing layer 4 containing quantum dots QD is disposed on the light extraction side.

  The quantum dot according to the present invention has a function of supplementing the emission color of the light-emitting layer by light emission that receives phosphorescence or fluorescence emitted from the light-emitting layer and is photoexcited in a down-conversion manner. The polysilazane-containing layer 4 containing is arranged on the surface side that emits light emitted by the light emitting member unit to the outside, that is, on the light extraction side.

  The light extraction side referred to in the present invention will be described with reference to FIG.

  In the configuration shown in FIG. 1A, the emitted light L is emitted below the paper surface.

  An organic EL element has a pair of opposed electrodes, but at least one of the electrodes is provided with a light-transmitting electrode, and the surface on which the light-transmitting electrode is disposed is light extraction. On the side. In FIG. 1A, the first electrode 6 is a light-transmitting electrode, preferably a transparent electrode composed of a silver thin film.

  In the case where both of the opposing electrodes are made of light-transmitting electrodes, both side surfaces sandwiching the light emitting layer are the light extraction side, and in the present invention, at least one light extraction side has a polysilazane-containing layer. 4, and more preferably, the polysilazane-containing layer 4 is disposed on both sides.

[Neutral area]
In this invention, it is a preferable aspect that the polysilazane content layer containing a quantum dot is located in the neutral area | region of the stress when an organic electroluminescent element receives a bending moment.

  By placing the polysilazane-containing layer containing quantum dots in the neutral region of the stress defined in the present invention, even when the organic EL element is subjected to an external pressure that causes bending, the polysilazane-containing layer is not stressed or very little This is a configuration that only occurs.

  That is, in the present invention, when a bending stress is applied to the organic EL element, the tensile stress TS generated on the bent surface side and the compressive stress CS generated on the back surface side are not generated or are extremely low even if generated. The region indicating the value is referred to as a neutral region (hereinafter also referred to as a neutral plane or a neutral portion). The center point of this neutral region is called a neutral point or neutral axis.

  In the present invention, the stress neutral region of the organic EL element when subjected to a bending moment extends from the lowermost backcoat layer 3 to the sealing member located on the outermost surface in the configuration shown in FIG. It can obtain | require based on each longitudinal elastic constant of the constituent material included.

  The stress central region will be further described with reference to FIG.

  In the organic EL element 1 shown in FIG. 2, the structure described in FIG. 1A is shown as an example.

  An organic EL element 1 shown in FIG. 2A has a polysilazane-containing layer 4 containing quantum dots according to the present invention, a gas barrier layer 5 on a flexible resin substrate 2 having a back coat layer 3 on the back surface. The first electrode 6, the organic functional layer unit 7, the second electrode 8, and the sealing member 9 are stacked. In such a configuration, the first electrode is a light transmissive electrode, and the side on which the flexible resin substrate 2 is provided is the light extraction side.

  When a bending force F is applied to both ends on the surface side of the organic EL element 1 having such a configuration, a tensile force T (Tensile force) acts in the horizontal direction on the surface side having the sealing member 9 and the like. 2 (b) and (c), a tensile stress TS (Tensile stress) is generated in the depth direction from the surface of the organic EL element 1, and the tensile stress TS is a sealing portion that is a surface portion. It gradually attenuates from the region of the member 9 toward the center, and becomes zero or extremely small stress at a certain point (neutral surface).

  On the other hand, on the reverse side of the organic EL element 1 (the side having the back coat layer 3), conversely, a compressive force C (compressive force) acts in the horizontal direction, and is exemplified in FIGS. 2B and 2C. As described above, a compressive stress CS (Compressive stress) is generated in the depth direction from the back surface of the organic EL element 1, and the compressive stress CS gradually increases from the back coat layer 3 region, which is the back surface portion, toward the center portion. Damping and zero or very little stress at some point (neutral plane).

  As described above, a region where each stress received when bent is zero or extremely small is a neutral region. In the present invention, when the total film thickness of the organic EL element 1 is D, the point at which each stress received when bent is zero or extremely small from the neutral plane (or also referred to as the neutral point). A film thickness range of ± 10% of the thickness D is defined as a neutral region.

  In the present invention, as a specific measurement procedure of the neutral point or the neutral region, a method for measuring a neutral plane described in Japanese Patent Application Laid-Open No. 2005-251671, or a neutral method described in Japanese Patent Application Laid-Open No. 2006-58764. It can be measured according to the method for determining the surface.

  In the present invention, disposing the polysilazane-containing layer 4 containing the quantum dots according to the present invention in the neutral region measured by the above method, etc., is excellent in durability without the quantum dots receiving excessive stress. An organic EL element can be obtained.

  As a method of disposing the polysilazane-containing layer 4 in the neutral region defined in the present invention, the longitudinal elastic constant of each layer is controlled based on the constituent material of each layer of the organic EL element 1, and the elastic modulus is emphasized at a predetermined position. The method for forming the neutral region, or the layer thickness and the layer arrangement of each constituent layer are appropriately controlled, and the polysilazane-containing layer 4 is arranged in the neutral region.

  In the configuration of the organic EL element of the present invention, in many cases, the thickness of the polysilazane-containing layer is thicker than the thickness of the neutral region. In such a configuration, the entire region of the neutral region is used. Even if the polysilazane-containing layer 4 is arranged so as to overlap, the polysilazane-containing layer is present in an area of 50% or more, preferably 80% or more of the neutral area. May be.

<Polysilazane-containing layer>
The polysilazane-containing layer according to the present invention is arranged on the light extraction side and contains at least quantum dots and polysilazane.

[Quantum dots]
First, details of the quantum dots applied to the present invention will be described.

  The quantum dot according to the present invention is a fine particle having a particle diameter of several nanometers to several tens of nanometers, which is composed of a crystal of a semiconductor material and has a quantum confinement effect, and can obtain the quantum dot effect shown below.

  Specifically, the particle diameter of the quantum dots (fine particles) according to the present invention is preferably in the range of 1 to 20 nm, and more preferably in the range of 1 to 10 nm.

  The energy level E of such a quantum dot is generally expressed by the following formula (I) when the Planck constant is “h”, the effective mass of the electron is “m”, and the radius of the fine particle is “R”. Is done.

Formula (I): E∝h ² / mR ²
As shown by the formula (I), the band gap of the quantum dot increases in proportion to “R ⁻² ”, and a so-called 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 diameter of the fine particles, it is possible to provide diversity not found in ordinary atoms. For this reason, electrical energy can be converted into light of the desired wavelength by exciting electrons with light or applying voltage to organic EL elements that contain quantum dots to confine electrons and holes in the quantum dots and recombine them. Can be emitted. In the present invention, such a light-emitting quantum dot material is defined as a quantum dot.

  As described above, the average particle diameter of the quantum dots is about several nm to several tens of nm. However, when the organic EL element is used as a white light emitting material, the average particle diameter is set to an average particle diameter corresponding to a target emission color. For example, when it is desired to obtain red light emission, the average particle diameter of the quantum dots is preferably set within a range of 3.0 to 20 nm. When green light emission is desired to be obtained, the average particle diameter of the quantum dots is set. It is preferable to set within the range of 1.5 to 10 nm, and when obtaining blue light emission, it is preferable to set the average particle diameter of the quantum dots within the range of 1.0 to 3.0 nm.

  As a method for measuring the average particle diameter, a known method can be used. For example, the quantum dot particles are observed with a transmission electron microscope (TEM), and the number average particle size of the particle size distribution is obtained therefrom, or a particle size measuring device using a dynamic light scattering method, for example, manufactured by Malvern, “It can be measured using ZETASIZER Nano Series Nano-ZS. In addition, 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 a quantum dot, etc. However, in the present invention, a measurement method using a particle size measuring apparatus by a dynamic light scattering method (“ZETASIZER Nano Series Nano-ZS” manufactured by Malvern) is preferable.

  The addition amount of the quantum dots is preferably in the range of 0.01 to 50% by mass, and in the range of 0.05 to 25% by mass, when the total constituent substances of the polysilazane-containing layer are 100% by mass. More preferably, it is most preferably in the range of 0.1 to 20% by mass. If the addition amount is 0.01% by mass or more, white light emission with sufficient luminance efficiency and good color rendering can be obtained, and if it is 50% by mass or less, an appropriate distance between quantum dot particles can be maintained. The size effect can be exhibited sufficiently.

<Components of quantum dots>
Examples of the constituent material of the quantum dot include a simple substance of a group 14 element of the periodic table such as carbon, silicon, germanium, and tin, a simple substance of a group 15 element of the periodic table such as phosphorus (black phosphorus), and a periodicity of selenium, tellurium, and the like. Table 16 group element simple substance, compound consisting of a plurality of periodic table group 14 elements such as silicon carbide (SiC), tin (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), lead sulfide (II) ) (PbS), lead selenide (II) (PbSe), lead telluride (II) (PbTe) periodic table group 14 element and periodic table group 16 element compound, boron nitride (BN), phosphorus Boron bromide (BP), Boron arsenide (BAs), Aluminum nitride (AlN , Aluminum phosphide (AlP), aluminum arsenide (AlAs), aluminum antimonide (AlSb), gallium nitride (GaN), gallium phosphide (GaP), gallium arsenide (GaAs), gallium antimonide (GaSb), nitride Compounds of Group 13 elements of the periodic table and Group 15 elements of the periodic table (or III-V compounds) such as indium (InN), indium phosphide (InP), indium arsenide (InAs), indium antimonide (InSb) Semiconductor), aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), gallium sulfide (Ga ₂ S ₃ ), gallium selenide (Ga ₂ Se ₃ ), gallium telluride (Ga ₂ Te ₃ ) , indium oxide _{(In 2 O} 3), indium sulfide _{(In 2 S} 3), selenide Indium _(In 2 _Se 3), telluride, indium _(In 2 Te ₃₎ Periodic Table compounds of a Group 13 element and Periodic Table Group 16 element such as, thallium chloride (I) (TlCl), thallium bromide (I ) (TlBr), thallium iodide (I) (TlI) and other group 13 elements of the periodic table and group 17 elements of the periodic table, 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 sulfide (HgS), mercury selenide (HgSe), telluride mercury (HgTe) periodic table group 12 element and the periodic table compound of group 16 element such as (or II-VI compound semiconductor), arsenic sulfide _{(III) (as 2 S} 3), Se Nkahiso _{(III) (As 2 Se 3} ), tellurium arsenic _{(III) (As 2 Te 3} ), antimony sulfide _{(III) (Sb 2 S 3} ), selenium antimony _{(III) (Sb 2 Se 3} ) Antimony telluride (III) (Sb ₂ Te ₃ ), bismuth sulfide (III) (Bi ₂ S ₃ ), bismuth selenide (III) (Bi ₂ Se ₃ ), bismuth telluride (III) (Bi ₂ Te ₃ ) ) Etc. Periodic Table Group 15 elements and Periodic Table Group 16 elements, Periodic Table Group 11 elements such as copper (I) (Cu ₂ O), copper selenide (Cu ₂ Se), etc. And compounds of Group 16 elements of the periodic table, copper chloride (I) (CuCl), copper bromide (I) (CuBr), copper iodide (I) (CuI), silver chloride (AgCl), silver bromide ( AgBr) and other compounds of Group 11 elements of the periodic table and Group 17 elements of the periodic table; Group 9 elements of the periodic table such as Kell (II) (NiO), Group 9 elements of the periodic table, Group 9 of the periodic table such as cobalt oxide (II) (CoO), cobalt sulfide (II) (CoS) A compound of an element and a group 16 element of the periodic table, a compound of a group 8 element of the periodic table and a group 16 element of the periodic table, such as triiron tetroxide (Fe ₃ O ₄ ), iron (II) sulfide (FeS), Periodic table such as manganese oxide (II) (MnO), periodic table group 7 elements and periodic table group 16 elements, molybdenum sulfide (IV) (MoS ₂ ), tungsten oxide (IV) (WO ₂ ), etc. Periodic table such as compounds of Group 6 elements and Group 16 elements, vanadium oxide (II) (VO), vanadium oxide (IV) (VO ₂ ), tantalum oxide (V) (Ta ₂ O ₅ ), etc. 5 group element and the periodic table compounds of group 16 elements, titanium oxide _(TiO 2, _Ti 2 O _{, Ti 2 O 3, Ti 5} O 9 , etc.) compounds of the periodic table Group 4 element and Periodic Table Group 16 element such as, Group 2, such as magnesium sulfide (MgS), magnesium selenide (MgSe) Compound of element and group 16 element of periodic table, cadmium oxide (II) chromium (III) (CdCr ₂ O ₄ ), cadmium selenide (II) chromium (III) (CdCr ₂ Se ₄ ), copper (II) sulfide Examples thereof include chalcogen spinels such as chromium (III) (CuCr ₂ S ₄ ), mercury (II) selenide (III) (HgCr ₂ Se ₄ ), barium titanate (BaTiO ₃ ), etc., but SnS ₂ , SnS, Compound of periodic table group 14 element and periodic table group 16 element such as SnSe, SnTe, PbS, PbSe, PbTe, GaN, GaP, GaAs, GaSb, InN, InP, InA III-V group compound semiconductors such as s and 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 Compounds of group 13 elements of the periodic table such as ₃ and group 16 elements of the periodic table, II-VI group compounds such as ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgO, HgS, HgSe, HgTe Semiconductor, As ₂ O ₃ , As ₂ S ₃ , As ₂ Se ₃ , As ₂ Te ₃ , Sb ₂ O ₃ , Sb ₂ S ₃ , 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 compound, MgS, MgSe periodic table group 2 element and periodic table group 16 element Compounds are preferred, among Also, Si, Ge, GaN, GaP, InN, InP, Ga ₂ O ₃ , Ga ₂ S ₃ , In ₂ O ₃ , In ₂ S ₃ , ZnO, ZnS, CdO, and CdS are more preferable. Since these substances do not contain highly toxic negative elements, they are excellent in environmental pollution resistance and safety to living organisms, and because a pure spectrum can be stably obtained in the visible light region, organic EL This is advantageous for forming the device. Of these materials, CdSe, ZnSe, and CdS are preferable in terms of light emission stability. From the viewpoints of luminous efficiency, high refractive index, and safety, ZnO and ZnS quantum dots are preferable. Moreover, said material may be used by 1 type and may be used in combination of 2 or more type.

  Note that the above-described quantum dots can be doped with a small amount of various elements as impurities as necessary. By adding such a doping substance, the emission characteristics can be greatly improved.

  The band gap of the quantum dots according to the present invention is preferably smaller than the band gap of the host compound contained in the light emitting layer by 0.1 eV or more.

  Moreover, it is most preferable that the band gap of at least one kind of quantum dot is 0.1 eV or more larger than the band gap of the blue phosphorescent compound contained in the light emitting layer. Specifically, it is preferably in the range of 1.8 to 3.2 eV, more preferably in the range of 2.2 to 3 eV, and most preferably in the range of 2.6 to 3.0 eV.

  In the case of the quantum dot which is an inorganic substance, the band gap as used in the present invention refers to the energy difference between the valence band and the conduction band as the band gap in the quantum dot, and the band gap as used in the phosphorescent light-emitting dopant and host compound which are organic substances. (EV) refers to the energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO).

  The band gap (eV) of a quantum dot can be measured using a Tauc plot.

  A Tauc plot, which is one of the optical scientific measurement methods of the band gap (eV), will be described.

The measurement principle of the band gap (E ₀ ) using the Tauc plot is shown below.

In the region of relatively large absorption near the optical absorption edge on the long wavelength side of the semiconductor material, between the light absorption coefficient α and the light energy hν (where h is the Planck constant and ν is the frequency), and the bandcap energy E ₀ Is considered to hold the following equation (A).

Formula (A): αhν = B (hν−E ₀ ) ²
Therefore, an absorption spectrum is measured, and hν is plotted (so-called Tauc plot) with respect to (αhν) raised to the 0.5th power, and the value of hν at α = 0 obtained by extrapolating the straight section is sought. The band gap energy E ₀ of the quantum dot is obtained.

  Further, the band gap (eV) in the phosphorescent light-emitting dopant that is an organic substance and the host compound can be determined according to the following method.

  The energy level of HOMO was measured with a photoelectron spectrometer AC-2 (manufactured by Riken Keiki Co., Ltd.), and the energy level of LUMO was calculated from the end of absorption wavelength (λth (nm)) using the following equation: A band energy gap (HOMO-LUMO energy gap) was determined. The numerical values are displayed as absolute values (ev).

(LUMO energy level) = (HOMO energy level) + 1240 / λth
The energy difference between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) measured by the above method is obtained, and this is used as the band gap (eV) in the phosphorescent dopant and host compound which are organic substances. .

  As another method for estimating the energy levels of these organic and inorganic functional materials, energy levels required by scanning tunneling spectroscopy, ultraviolet photoelectron spectroscopy, X-ray photoelectron spectroscopy, Auger electron spectroscopy are used. And a method for optically estimating the band gap.

  In addition, these quantum dots not only emit light due to direct recombination of holes and electrons in the quantum dots, but also the excitation generated in the organic electron block hole transport layer, light emitting layer, or hole block electron transport layer. The energy of the child may be absorbed by the quantum dot to obtain light emission from the core of the quantum dot. Since these quantum dots are lightly doped, other phosphorescent compounds can also absorb the exciton energy to obtain light emission.

<Core / shell structure>
The surface of the quantum dot is preferably coated with an inert inorganic coating layer or a coating composed of an organic ligand. That is, the surface of the quantum dot has a core / shell structure having a core region made of a quantum dot material and a shell region made of an inert inorganic coating layer or an organic ligand. Is preferred.

  This core / shell structure is preferably formed of at least two kinds of compounds, and a gradient structure (gradient structure) may be formed of two or more kinds of compounds. This effectively prevents aggregation of the quantum dots in the coating liquid, improves the dispersibility of the quantum dots, improves the luminance efficiency, and prevents color shifts that occur when driven continuously. Can be suppressed. Further, the light emission characteristics can be stably obtained due to the presence of the coating layer.

  Moreover, when the surface of the quantum dot is covered with a coating (shell part), a surface modifier as described later can be reliably supported in the vicinity of the surface of the quantum dot.

  Although the thickness of a film (shell part) is not specifically limited, It is preferable to exist in the range of 0.1-10 nm, and it is more preferable to exist in the range of 0.1-5 nm.

  In general, the emission color can be controlled by the average particle diameter of the quantum dots, and if the thickness of the coating is within the above range, the thickness of the coating can be determined from the thickness corresponding to several atoms. The thickness is less than one, the quantum dots can be filled with high density, and a sufficient amount of light emission can be obtained. In addition, the presence of the coating can suppress non-luminous electron energy transfer due to defects existing on the particle surfaces of the core particles and electron traps on the dangling bonds, thereby suppressing a decrease in quantum efficiency.

<Functional surface modifier>
When the organic functional layer containing quantum dots is formed by a wet coating method, it is preferable that a surface modifier is attached in the vicinity of the surface of the quantum dots in the coating solution used for the organic functional layer. Thereby, especially the dispersion stability of the quantum dot in a coating liquid can be made excellent. In addition, when a quantum dot is manufactured, by attaching a surface modifier to the surface of the quantum dot, the shape of the formed quantum dot becomes highly spherical, and the particle size distribution of the quantum dot can be kept narrow. Therefore, it can be made particularly excellent.

  Functional surface modifiers applicable in the present invention may be those directly attached to the surface of the quantum dots, or those attached via a shell (the surface modifier is directly attached to the shell. In other words, it may not be in contact with the core of the quantum dot.

  Examples of the surface modifier include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; tripropylphosphine, tributylphosphine, trihexylphosphine, trioctylphosphine, and the like. Trialkylphosphines; polyoxyethylene alkylphenyl ethers such as polyoxyethylene n-octylphenyl ether and polyoxyethylene n-nonylphenyl ether; tri (n-hexyl) amine, tri (n-octyl) amine, tri ( Tertiary amines such as n-decyl) amine; tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide Organic phosphorus compounds such as tridecylphosphine oxide; polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate; organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine and quinolines; hexylamine and octyl Aminoalkanes such as amine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, octadecylamine; dialkyl sulfides such as dibutyl sulfide; dialkyl sulfoxides such as dimethyl sulfoxide and dibutyl sulfoxide; sulfur-containing aromatic compounds such as thiophene Organic sulfur compounds such as: higher fatty acids such as palmitic acid, stearic acid and oleic acid; alcohols; sorbitan fatty acid esters; fatty acid-modified polyesters Ters; tertiary amine-modified polyurethanes; polyethyleneimines and the like. When the quantum dots are prepared by the method described later, the surface modifier may be a fine particle of quantum dots in a high-temperature liquid phase. It is preferable that the substance is coordinated to be stabilized, specifically, trialkylphosphines, organic phosphorus compounds, aminoalkanes, tertiary amines, organic nitrogen compounds, dialkyl sulfides, dialkyl sulfoxides. , Organic sulfur compounds, higher fatty acids and alcohols are preferred. By using such a surface modifier, the dispersibility of the quantum dots in the coating solution can be made particularly excellent. Moreover, the shape of the quantum dot formed at the time of manufacture of a quantum dot can be made into a higher sphericity, and the particle size distribution of a quantum dot can be made sharper.

  In the present invention, as described above, the quantum dot size (average particle diameter) is preferably in the range of 1 to 20 nm. In the present invention, the size of the quantum dots means the total area composed of a core region composed of a quantum dot material, a shell region composed of an inert inorganic coating layer or an organic ligand, and a surface modifier. Represents size. If the surface modifier or shell is not included, the size does not include it.

<Manufacturing method of quantum dots>
Examples of the method for producing quantum dots include the following conventional methods for producing quantum dots and the like, but are not limited thereto, and any known method can be used.

  For example, as a process under high vacuum, a molecular beam epitaxy method, a CVD method or the like; As a liquid phase production method, an aqueous raw material is an alkane such as n-heptane, n-octane, isooctane, or benzene, toluene. Inverted micelles, which exist as reverse micelles in non-polar organic solvents such as aromatic hydrocarbons such as xylene, and crystal growth in this reverse micelle phase, inject a thermally decomposable raw material into a high-temperature liquid-phase organic medium Examples thereof include a hot soap method for crystal growth and a solution reaction method involving crystal growth at a relatively low temperature using an acid-base reaction as a driving force, as in the hot soap method. Any method can be used from these production methods, and among these, the liquid phase production method is preferred.

  In the liquid phase production method, the organic surface modifier present on the surface when the quantum dots are synthesized is referred to as an initial surface modifier. For example, examples of the initial surface modifier in the hot soap method include trialkylphosphines, trialkylphosphine oxides, alkylamines, dialkyl sulfoxides, alkanephosphonic acid and the like. These initial surface modifiers are preferably exchanged for the above-described functional surface modifiers by an exchange reaction.

  Specifically, for example, the initial surface modifier such as trioctyl phosphine oxide obtained by the hot soap method described above is obtained by performing the functional surface modification described above by an exchange reaction performed in a liquid phase containing the functional surface modifier. It is possible to replace it with an agent.

  Below, an example of the manufacturing method of a quantum dot is shown.

<1> Production example 1 of quantum dots
First, CdO powder (1.6 mmol, 0.206 g; Aldrich, + 99.99%) and oleic acid (6.4 mmol, 1.8 g; Aldrich, 95%) were mixed with 40 mL of trioctylamine (TOA, Aldrich, 95). %). The mixed solution was heat-treated at 150 ° C. while stirring at high speed, and the temperature was increased to 300 ° C. while N ₂ was allowed to flow. Then, at 300 ° C., 0.2 ml of 2.0 mol / L Se (Alfa Aesar) added to trioctylphosphine (TOP, Strem, 97%) is injected into the Cd-containing mixture at high speed.

  After 90 seconds, 1.2 mmol of n-octanethiol added to TOA (210 μl in 6 ml) is injected at a rate of 1 ml / min using a syringe pump and allowed to react for 40 minutes.

Next, 0.92 g of zinc acetate and 2.8 g of oleic acid are dissolved in 20 ml of TOA at 200 ° C. in an N ₂ atmosphere to prepare a 0.25 mol / L Zn precursor solution.

  A 16 ml aliquot of Zn-oleic acid solution (heated at 100 ° C.) is then injected into the Cd-containing reaction medium at a rate of 2 ml / min. Then, 6.4 mmol n-octanethiol in TOA (1.12 ml in 6 ml) is infused at a rate of 1 ml / min using a syringe pump.

  The entire reaction is performed over 2 hours. After the reaction is complete, the product is cooled to about 50-60 ° C. and the organic sludge is removed by centrifugation (5600 rpm). Add ethanol (Fisher, HPLC grade) until there is no opaque mass. Next, the precipitate obtained by centrifugation is dissolved in toluene (Sigma-Aldrich, Anhydrous 99.8%), whereby a CdSe / CdS / ZnS core / shell quantum dot colloidal solution can be obtained.

<2> Production example 2 of quantum dots
When a quantum dot having a core / shell structure of CdSe / ZnS is to be obtained, (CH ₃ ) ₂ Cd (dimethyl cadmium), TOPSe (trioctylphosphine selenium) is used as an organic solvent using TOPO (trioxyphosphine oxide) as a surfactant. A precursor material corresponding to the core (CdSe) is injected to generate a crystal, and is maintained at a high temperature for a certain period of time so that the crystal grows at a certain size, and then corresponds to the shell (ZnS). CdSe / ZnS quantum dots capped with TOPO can be obtained by injecting the precursor material so that a shell is formed on the surface of the core already formed.

<3> Production example 3 of quantum dots
Under an argon stream, 7.5 g of tri-n-octylphosphine oxide (TOPO) (manufactured by Kanto Chemical Co., Ltd.), 2.9 g of stearic acid (manufactured by Kanto Chemical Co., Ltd.), and 620 mg of n-tetradecylphosphonic acid (manufactured by AVOCADO) Then, 250 mg of cadmium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) is added and heated to 370 ° C. After naturally cooling this to 270 ° C., a solution of 200 mg of selenium (STREM CHEMICAL) dissolved in 2.5 ml of tributylphosphine (manufactured by Kanto Chemical Co.) was added in advance, dried under reduced pressure, and CdSe coated with TOPO. Get fine particles.

  Next, 15 g of TOPO was added to the obtained CdSe fine particles and heated, and subsequently, a solution of 1.1 g of zinc diethyldithiocarbamate (manufactured by Tokyo Chemical Industry) dissolved in 10 ml of trioctylphosphine (manufactured by Sigma Aldrich) at 270 ° C. In addition, nanoparticles having CdSe nanocrystals with TOPO fixed on the surface and using ZnS as a shell (hereinafter also referred to as TOPO fixed quantum dots) were obtained. Note that the quantum dots in this state are soluble in an organic solvent such as toluene and tetrahydrofuran (abbreviation: THF).

  Thereafter, the prepared TOPO fixed quantum dots were dissolved in THF, heated to 85 ° C., and N-[(S) -3-mercapto-2-methylpropionyl] -L-proline (Sigma) dissolved in ethanol there. 100 mg of Aldrich) is added dropwise and refluxed for about 12 hours. After refluxing for 12 hours, an aqueous NaOH solution was added, and the mixture was heated at 90 ° C. for 2 hours to evaporate THF. By purifying and concentrating the obtained unpurified quantum dots using ultrafiltration (Millipore, "Microcon") and Sephadex column (Amersham Biosciences, "MicroSpin G-25 Columns"). A hydrophilic quantum dot in which N-[(S) -3-mercapto-2-methylpropionyl] -L-proline is immobilized on the surface of the quantum dot can be produced.

[Polysilazane]
The polysilazane-containing layer containing quantum dots according to the present invention contains at least one polysilazane compound of polysilazane and a modified polysilazane. The modified polysilazane is a compound that is generated by subjecting polysilazane to a modification treatment and includes at least one selected from silicon oxide, silicon nitride, and silicon oxynitride.

  Here, the polysilazane may be dispersed together with the quantum dots in the polysilazane-containing layer forming coating solution, or the quantum dots are previously coated with polysilazane, and the quantum dots are dispersed in the polysilazane-containing layer forming coating solution. May be. In the present invention, the term “cover” refers to covering the surface of the quantum dot, but may not cover the entire surface of the quantum dot, but may cover a part thereof. May be.

  In the polysilazane-containing layer, by containing at least one compound among the polysilazane and the polysilazane modified product, durability that can suppress the quantum dots from coming into contact with oxygen or the like over a long period of time can be imparted. Furthermore, it can be set as a highly transparent layer.

  In the polysilazane-containing layer according to the present invention, the polysilazane-containing layer is not formed in the state where all of the ceramic precursor inorganic polymer that is the polysilazane is formed as it is, and the drying process in the layer forming stage The polysilazane is modified to silica or the like by a heat treatment such as forcibly or a modification treatment such as a forced annealing treatment, ultraviolet irradiation treatment, or vacuum ultraviolet irradiation treatment described later. At this time, it is not necessary to modify all of the polysilazane, and at least a part of the polysilazane may be modified.

(1) Constituent material of polysilazane “Polysilazane” according to the present invention is a polymer having a silicon-nitrogen bond, SiO _{2 made of} Si—N, Si—H, NH, etc., Si ₃ N ₄ and both Ceramic precursor inorganic polymer such as intermediate solid solution SiOxNy.

  The polysilazane is preferably a compound that is converted to silica by being ceramicized at a relatively low temperature so as to be applied so as not to impair the properties of the flexible resin substrate. For example, the following is described in JP-A-8-112879. A compound having a main skeleton composed of units represented by formula (I) is preferred.

In the general formula (I), R ₁ , R ₂ and R ₃ each independently represents a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, an alkylamino group, an alkoxy group, or the like. Represent.

In the present invention, from the viewpoint of the denseness of the resulting polysilazane-containing layer, perhydropolysilazane (abbreviation: PHPS) in which all of R ₁ , R ₂ and R ₃ are hydrogen atoms is particularly preferable.

  In addition, the organopolysilazane in which a part of the hydrogen atom part bonded to Si is substituted with an alkyl group or the like has an alkyl group such as a methyl group, so that the base is the flexible resin base material 2 Has improved adhesion to the polysilazane-containing layer 4 and can impart toughness to the hard and brittle ceramic film of polysilazane, suppressing the occurrence of cracks even when the film thickness (average film thickness) is increased. There are advantages to being Accordingly, perhydropolysilazane and organopolysilazane may be appropriately selected according to the application, and may be used in combination.

  Perhydropolysilazane is presumed to have a linear structure and a ring structure centered on 6- and 8-membered rings. Its molecular weight is about 600 to 2000 (polystyrene conversion) in terms of number average molecular weight (Mn), and there is a liquid or solid substance, and its state varies depending on the molecular weight. These are marketed in a solution state dissolved in an organic solvent, and the commercially available product can be used as it is as a polysilazane-containing coating solution.

  As another example of the polysilazane compound that is ceramicized at a low temperature, a silicon alkoxide-added polysilazane obtained by reacting a silicon alkoxide with a polysilazane having a main skeleton composed of a unit represented by the general formula (I) (for example, a special No. 5-238827), a glycidol-added polysilazane obtained by reacting glycidol (for example, see JP-A-6-122852), an alcohol-added polysilazane obtained by reacting an alcohol (for example, JP-A-6-6). -240208), a metal carboxylate-added polysilazane obtained by reacting a metal carboxylate (see, for example, JP-A-6-299118), and a metal-containing acetylacetonate complex. Acetylacetonate complex-added polysilaza (E.g., JP-A-6-306329 JP reference.), Fine metal particles of the metal particles added polysilazane obtained by adding (e.g., JP-A-7-196986 JP reference.), And the like.

  As an organic solvent for preparing a coating liquid for forming a polysilazane-containing layer containing quantum dots and polysilazane, it is preferable to avoid the use of an alcohol-based organic solvent or a water-containing organic solvent that easily reacts with polysilazane. Therefore, specifically, hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons, halogenated hydrocarbon solvents, and ethers such as aliphatic ethers and alicyclic ethers can be used. . Specifically, there are hydrocarbons such as pentane, hexane, cyclohexane, toluene, xylene, solvesso and turben, halogen hydrocarbons such as methylene chloride and trichloroethane, ethers such as dibutyl ether, dioxane and tetrahydrofuran. These organic solvents may be selected according to characteristics such as the solubility of polysilazane and the evaporation rate of the organic solvent, and a plurality of organic solvents may be mixed.

  The polysilazane concentration in the coating liquid for forming a polysilazane-containing layer containing quantum dots and polysilazane varies depending on the film thickness of the target polysilazane-containing layer and the pot life of the coating liquid, but is in the range of 0.2 to 35% by mass. It is preferable that

  An amine or metal catalyst can be added to the polysilazane-containing coating solution for forming a polysilazane-containing layer in order to promote the modification to the silicon oxide compound. Specific examples include Aquamica NAX120-20, NN110, NN310, NN320, NL110A, NL120A, NL150A, NP110, NP140, and SP140 manufactured by AZ Electronic Materials.

[Formation of polysilazane-containing layer]
The polysilazane-containing layer containing quantum dots is preferably formed by a wet process using the polysilazane-containing layer forming coating solution. For example, spin coating method, casting method, die coating method, blade coating method, roll coating method, ink jet method, printing method, spray coating method, curtain coating method, LB method (Langmuir Brodgett method), etc. be able to.

  In the present invention, the thickness of the polysilazane-containing layer 4 containing quantum dots can be appropriately set according to the purpose. For example, the thickness after drying is preferably in the range of 1 nm to 100 μm, more preferably in the range of 10 nm to 10 μm, and most preferably in the range of 10 nm to 1 μm.

  In the polysilazane-containing layer formed by the coating liquid for forming a polysilazane-containing layer containing quantum dots and polysilazane used in the present invention, it is preferable that moisture is removed before or during the modification treatment. Therefore, you may divide into the 1st drying process aiming at the removal of the organic solvent in a polysilazane content layer, and the 2nd drying process aiming at the removal of the water in a polysilazane content layer following that.

  In the first drying step, mainly the organic solvent is removed, and therefore, the drying conditions can be appropriately determined by a method such as heat treatment, and the conditions may be such that moisture is removed at this time. The heat treatment temperature is preferably a high temperature from the viewpoint of rapid processing, but it is preferable to appropriately determine the temperature and treatment time in consideration of thermal damage to the flexible resin substrate 2. For example, when a polyethylene terephthalate substrate having a glass transition temperature (Tg) of 70 ° C. is used as the flexible resin substrate 2, the heat treatment temperature is preferably set to 150 ° C. or less. The treatment time is preferably set to a short time so that the solvent is removed and thermal damage to the substrate 2 is reduced. If the heat treatment temperature is 150 ° C. or less, the treatment time can be set within 30 minutes.

  The second drying step is a step for removing moisture from the polysilazane-containing layer 4, and a method for removing moisture is preferably maintained in a low humidity environment and dehumidified. Since humidity in a low-humidity environment varies depending on temperature, a preferable form is shown for the relationship between temperature and humidity by defining the dew point temperature. A preferable dew point temperature is 4 ° C. or less (temperature 25 ° C./humidity 25%), a more preferable dew point temperature is −8 ° C. (temperature 25 ° C./humidity 10%) or less, and a more preferable dew point temperature is −31 ° C. (temperature 25 ° C./temperature). Humidity 1%) or less. Moreover, you may dry under reduced pressure in order to make it easy to remove a water | moisture content. The pressure in vacuum drying can be selected within the range of normal pressure to 0.1 MPa.

  As a preferable condition of the second drying step with respect to the condition of the first drying step, for example, when the solvent is removed in the range of a temperature of 60 to 150 ° C. and a processing time of 1 to 30 minutes as the first drying step, the second drying step The dew point is 4 ° C. or less, and the treatment time is 5 minutes to 120 minutes.

  The polysilazane-containing layer according to the present invention is preferably subjected to a modification treatment while maintaining its state even after moisture is removed by the second drying step.

[Modification treatment of polysilazane-containing layer]
In this invention, it is a preferable aspect that the polysilazane content layer containing a quantum dot is a layer containing the polysilazane modified body in which the modification process was performed.

  The modification treatment is performed on the polysilazane constituting the polysilazane-containing layer, whereby a part or all of the polysilazane contained in the polysilazane-containing layer is modified into a polysilazane modified body.

  When polysilazane is dispersed together with quantum dots in the polysilazane-containing layer forming coating solution, the modification treatment is performed on the coating film formed by the polysilazane-containing layer forming coating solution.

  Specifically, a known method based on the conversion reaction of polysilazane can be selected for the modification treatment. The modification to the silicon oxide film or the silicon oxynitride film by the substitution reaction of silazane requires a heat treatment at 450 ° C. or higher, and is difficult to apply in the flexible resin substrate applied to the present invention. In order to apply to a flexible resin substrate, it is preferable to use a method such as plasma treatment, ozone treatment, ultraviolet irradiation treatment, or vacuum ultraviolet irradiation treatment capable of allowing the conversion reaction to proceed at a low temperature.

  In addition, when performing a modification process with respect to the coating layer containing polysilazane, it is preferable that the water | moisture content is removed as mentioned above before the said modification process.

  As the modification treatment of the present invention, ultraviolet irradiation, vacuum ultraviolet irradiation, and plasma irradiation are desirable, and vacuum ultraviolet irradiation is particularly preferable in terms of the modification effect of polysilazane.

  Hereinafter, an ultraviolet irradiation process and a vacuum ultraviolet irradiation process will be described as typical modification methods.

<Ultraviolet irradiation treatment>
One method of the modification treatment is ultraviolet irradiation treatment.

  Ozone and active oxygen atoms generated by ultraviolet rays (synonymous with ultraviolet light) have high oxidation ability, and can form silicon oxide or silicon oxynitride having high density and insulation properties at low temperatures. .

By this ultraviolet irradiation, the flexible resin base material is heated, and O ₂ and H ₂ O contributing to ceramicization (silica conversion) and polysilazane itself are excited and activated. The conversion to ceramics is promoted, and the resulting ceramic film becomes denser. The ultraviolet irradiation may be performed at the time of preparing the polysilazane-containing layer forming coating solution, or may be performed after the polysilazane-containing layer is formed with the polysilazane-containing layer forming coating solution.

  In the present invention, any commonly used ultraviolet ray generator can be used.

  In the present invention, “ultraviolet rays” generally refers to electromagnetic waves having a wavelength of 10 to 400 nm, but the vacuum ultraviolet ray (within a wavelength range of 10 to 200 nm) treatment described later and the wavelength range to be applied are classified. For this reason, in the case of ultraviolet irradiation treatment, ultraviolet rays having a wavelength within the range of 210 to 350 nm are preferably used.

  As the irradiation condition of the ultraviolet rays, the irradiation intensity and the irradiation time are set in a range in which the flexible resin substrate carrying the irradiated polysilazane-containing layer is not damaged.

When a flexible resin base material is used, for example, a 2 kW (80 W / cm × 25 cm) lamp is used, and the strength of the flexible resin base material surface is 20 to 300 mW / cm ² , preferably 50 to 200 mW / cm ^2. The distance between the flexible resin substrate and the ultraviolet irradiation lamp can be set so that the irradiation time is in the range of 0.1 second to 10 minutes.

  In general, when the temperature of the flexible resin during ultraviolet irradiation treatment is 150 ° C. or higher, the flexible resin base material is deformed or the strength is reduced. In addition, there is no general upper limit to the temperature of the flexible resin base material at the time of ultraviolet irradiation, and those skilled in the art can appropriately set the temperature depending on the type of the flexible resin base material to be applied. Moreover, there is no restriction | limiting in particular in ultraviolet irradiation atmosphere, What is necessary is just to implement in air.

  Examples of such ultraviolet light generation light sources include metal halide lamps, high-pressure mercury lamps, low-pressure mercury lamps, xenon arc lamps, carbon arc lamps, and excimer lamps (single wavelengths of 222 nm and 308 nm, for example, manufactured by USHIO INC.) ), A UV light laser and the like, and are not particularly limited. In addition, when irradiating the coating layer with the generated ultraviolet rays, it is desirable to apply the ultraviolet rays from the generation source to the coating layer after reflecting the ultraviolet rays from the generation source with a reflector in order to achieve uniform irradiation and improve efficiency. .

  The ultraviolet irradiation can be adapted to both batch processing and continuous processing, and can be appropriately selected depending on the shape of the flexible resin substrate. In addition, when the flexible resin base material having a polysilazane-containing layer on the surface is in the form of a long film, it is continuously irradiated with ultraviolet rays in the drying zone equipped with the ultraviolet ray source as described above while being conveyed. By doing so, it can be converted into ceramics. The time required for ultraviolet irradiation is generally 0.1 seconds to 10 minutes, preferably 0.5 seconds to 3 minutes, although it depends on the substrate to be applied and the composition and concentration of the coating solution.

<Vacuum UV irradiation treatment; Excimer irradiation treatment>
In the present invention, a more preferable method for the modification treatment is a treatment method by irradiation with vacuum ultraviolet rays.

  In the treatment method by vacuum ultraviolet irradiation, light energy of 100 to 200 nm, preferably light energy having a wavelength of 100 to 180 nm, which is larger than the interatomic bonding force in the polysilazane compound, is used, and the bonding of atoms is based only on photons called photon processes. This is a method of forming a silicon oxide film or the like in a relatively low temperature environment by causing an oxidation reaction with active oxygen or ozone to proceed while cutting directly by action.

  As a vacuum ultraviolet light source required for this, a rare gas excimer lamp is preferably used.

Here, since noble gas atoms such as Xe, Kr, Ar, Ne and the like are chemically bonded to form a molecule, it is called an inert gas. However, rare gas atoms (excited atoms) that have gained energy by discharge or the like can be combined with other atoms to form molecules. When the rare gas is xenon,
e + Xe → e + Xe ^*
Xe ^* + Xe + Xe → Xe ^{2 *} + Xe
Thus, when the excited excimer molecule Xe ^{2 *} transitions to the ground state, it emits excimer light having a wavelength of 172 nm. A feature of the excimer lamp is that the radiation is concentrated at one wavelength, and only the necessary light is hardly emitted, so that the efficiency is extremely high.

  Further, since no extra light is emitted, the temperature of the object can be kept low. Furthermore, since no time is required from start to restart, instant lighting and flashing are possible.

  In order to obtain excimer light emission, a method using dielectric gas barrier discharge is known. Dielectric gas barrier discharge is generated in a gas space by arranging a gas space between both electrodes via a dielectric (transparent quartz in the case of an excimer lamp) and applying a high frequency high voltage of several tens of kHz to the electrode. It is a very thin discharge called micro discharge similar to lightning. When the micro discharge streamer reaches the tube wall (dielectric), the electric charge accumulates on the surface of the dielectric, and the micro discharge disappears. Thus, the dielectric gas barrier discharge is a discharge in which micro discharge spreads over the entire tube wall and is repeatedly generated and extinguished. For this reason, flickering of light that can be seen with the naked eye occurs. Moreover, since a very high temperature streamer reaches a pipe wall directly locally, there is a possibility that deterioration of the pipe wall may be accelerated.

  As a method for efficiently obtaining excimer light emission, electrodeless electric field discharge can be used in addition to dielectric gas barrier discharge. Electrodeless electric field discharge by capacitive coupling, also called RF discharge. The lamp and electrodes and their arrangement may be basically the same as for dielectric gas barrier discharge, but the high frequency applied between the two electrodes is lit at several MHz. Since the electrodeless field discharge can provide a spatially and temporally uniform discharge, a long-life lamp without flickering can be obtained.

  In the case of dielectric gas barrier discharge, micro discharge occurs only between the electrodes, so in order to discharge in the entire discharge space, the outer electrode covers the entire outer surface and light is used to extract the light to the outside. Must be transparent. For this reason, an electrode in which a fine metal wire is formed in a net shape is used. Since this electrode uses as thin a line as possible so as not to block light, it is easily damaged by ozone generated by vacuum ultraviolet light in an oxygen atmosphere.

  In order to prevent this, it is necessary to create an atmosphere of an inert gas such as nitrogen around the lamp, that is, the inside of the irradiation apparatus, and provide a synthetic quartz window to extract the irradiation light. Synthetic quartz windows are not only expensive consumables, but also cause light loss.

  Since the double cylindrical lamp has an outer diameter of about 25 mm, the difference in distance to the irradiation surface cannot be ignored between the position directly below the lamp axis and the side surface of the lamp, resulting in a large difference in illuminance. Therefore, even if the lamps are closely arranged, a uniform illuminance distribution cannot be obtained. If the irradiation device is provided with a synthetic quartz window, the distance in the oxygen atmosphere can be made uniform, and a uniform illuminance distribution can be obtained.

  When electrodeless field discharge is used, it is not necessary to make the external electrodes mesh. The glow discharge spreads over the entire discharge space simply by providing an external electrode on a part of the outer surface of the lamp. As the external electrode, an electrode that also serves as a light reflector made of an aluminum block is usually used on the back of the lamp. However, since the outer diameter of the lamp is as large as in the case of the dielectric gas barrier discharge, synthetic quartz is required to obtain a uniform illuminance distribution.

  The biggest feature of the capillary excimer lamp is its simple structure. The quartz tube is closed at both ends, and only gas for excimer light emission is sealed inside. Therefore, a very inexpensive light source can be provided.

  Since the double cylindrical lamp is processed by closing both ends of the inner and outer tubes, it is more likely to be damaged by use and transportation than a thin tube lamp. Further, the outer diameter of the tube of the thin tube lamp is about 6 to 12 mm, and if it is too thick, a high voltage is required for starting.

  As the form of discharge, either dielectric gas barrier discharge or electrodeless field discharge can be used. The electrode may have a flat surface in contact with the lamp, but if the shape is matched to the curved surface of the lamp, the lamp can be firmly fixed and the discharge is more stable when the electrode is in close contact with the lamp. Also, if the curved surface is made into a mirror surface with aluminum, it also becomes a light reflector.

  The Xe excimer lamp is excellent in luminous efficiency because it emits ultraviolet light having a short wavelength of 172 nm at a single wavelength. Since this light has a large oxygen absorption coefficient, it can generate radical oxygen atom species and ozone at a high concentration with a very small amount of oxygen. In addition, it is known that the energy of light having a short wavelength of 172 nm for dissociating the bonds of organic substances has high ability. Due to the high energy of the active oxygen, ozone and ultraviolet radiation, the coating film containing polysilazane can be modified in a short time. Therefore, compared to low-pressure mercury lamps with wavelengths of 185 nm and 254 nm and plasma cleaning, it is possible to shorten the process time associated with high throughput, reduce the equipment area, and irradiate organic materials and plastic substrates that are easily damaged by heat. .

  Since the excimer lamp has high light generation efficiency, it can be lit with low power. In addition, light having a long wavelength that causes a temperature increase due to light is not emitted, and energy is irradiated at a single wavelength in the ultraviolet region, so that an increase in the surface temperature of the irradiation object is suppressed. For this reason, it is suitable for a flexible resin base material that is considered to be easily affected by heat.

<< Configuration of organic EL element >>
As the structure of the organic EL element, as shown in the typical structure in FIG. 1A, the details are described above on the flexible resin base material 2 having the back coat layer 3 on the back surface. It is the structure which laminated | stacked the polysilazane content layer 4, the gas barrier layer 5, the 1st electrode 6, the organic functional layer unit 7, the 2nd electrode 8, and the sealing member 9 which contain the quantum dot demonstrated by (1).

  Hereinafter, the detail of each component of the organic EL element except a polysilazane content layer is demonstrated.

[Flexible resin substrate]
The base material applied to the organic EL element of the present invention is a flexible resin substrate that can be bent (hereinafter also simply referred to as a resin base material or a base material). The flexible resin base material 2 is not particularly limited as long as it is a resin material that can hold each of the constituent layers described above.

  Examples of the flexible resin substrate applicable to the present invention include polyesters such as polyethylene terephthalate (abbreviation: PET), polyethylene naphthalate (abbreviation: PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate ( Abbreviations: TAC), cellulose acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, Shinji Tactic polystyrene, polycarbonate (abbreviation: PC), norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfur (Abbreviation: PES), polyphenylene sulfide, polysulfones, polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic and polyarylates, Arton (trade name, manufactured by JSR) and Appel ( And cycloolefin-based resins such as trade name Mitsui Chemicals).

  Among these flexible resin base materials, films such as polyethylene terephthalate (abbreviation: PET), polybutylene terephthalate, polyethylene naphthalate (abbreviation: PEN), polycarbonate (abbreviation: PC) and the like in terms of cost and availability. Is preferably used as a flexible resin substrate.

  The thickness of the flexible resin substrate is preferably in the range of 5 to 500 μm, more preferably in the range of 25 to 250 μm.

  Further, the flexible resin base material needs to be transparent. The flexible resin base material 2 is transparent, and each layer including the first electrode formed on the flexible resin base material 2 is also a layer having a high light transmittance, so that flexibility is achieved. Light can be extracted from the resin base material side. This flexible resin base material can also be suitably used as a sealing member (transparent substrate) for organic EL elements. The flexible resin substrate may be an unstretched film or a stretched film.

  The flexible resin base material applicable to the present invention can be manufactured by a conventionally known general film forming method. For example, an unstretched resin base material that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the resin base material is transported by a known method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, and tubular simultaneous biaxial stretching (vertical axis). A stretched resin substrate can be produced by stretching in the direction perpendicular to the direction of the resin substrate or the direction of transport of the resin substrate (horizontal axis). Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of the resin base material, it is preferably in the range of 2 to 10 times in the vertical axis direction and the horizontal axis direction.

  Moreover, this resin substrate may be subjected to a hydrophilic treatment such as a corona treatment on the surface of the substrate before forming a polysilazane layer or the like.

[Back coat layer]
In the organic EL element of the present invention, as shown in FIG. 1, a back coat layer, for example, on the surface of the flexible resin substrate 2 opposite to the surface on which the polysilazane-containing layer and the light emitting member unit U are formed. An antistatic layer or the like can be provided.

(Antistatic layer)
The antistatic layer has, for example, a function of preventing the film surface from being charged when the flexible resin base material is fed out from the laminated roll-shaped laminate.

  As a technique for imparting antistatic ability to the antistatic layer, there is a method of imparting conductivity to the antistatic layer and reducing the electric resistance value of the antistatic layer.

  For example, as an antistatic technique, a method of dispersing and containing a conductive filler as a conductive material in an antistatic layer, a method of using a conductive polymer, a method of dispersing or coating a metal compound on a surface, an organic sulfonic acid And an internal addition method using an anionic compound such as organic phosphoric acid, a method using a surface active type low molecular weight antistatic agent such as polyoxyethylene alkylamine, polyoxyethylene alkenylamine, and glycerin fatty acid ester, carbon There is a method of dispersing conductive fine particles such as black. In particular, it is preferable to use a method in which conductive fillers, which are conductive substances, are dispersed and contained.

  The antistatic layer preferably has an antistatic property by containing a conductive filler. As the conductive filler contained in the antistatic layer, there are conductive inorganic fine particles, among which metal fine particles, conductive inorganic oxide fine particles and the like can be used. In particular, conductive inorganic oxide fine particles can be preferably used. Examples of the metal fine particles include fine particles of gold, silver, palladium, ruthenium, rhodium, osmium, iridium, tin, antimony, indium and the like. Examples of the inorganic oxide fine particles include fine particles such as indium antimony pentoxide, tin oxide, zinc oxide, ITO (indium / tin oxide), ATO (antimony / tin oxide), and phosphorus-doped oxide. Among these, inorganic double oxide fine particles such as phosphorus-doped oxide are preferable because of their high conductivity and weather resistance.

  When dispersing the conductive filler in the antistatic layer, the primary particle diameter of the conductive filler is preferably 1 to 100 nm, particularly 1 to 50 nm in order not to lower the transparency of the antistatic layer. Is preferred. In order to ensure conductivity, the particles must be close to each other to some extent, so that the particle diameter is preferably 1 nm or more. If the particle diameter exceeds 100 nm, light is reflected and the light transmittance is lowered, which is not preferable.

  As the conductive inorganic oxide fine particles, commercially available fine particles can be used. Specifically, Cellax series (manufactured by Nissan Chemical Industries, Ltd.), P-30, P-32, P-35, P- 45, P-120, P-130 (all manufactured by JGC Catalysts & Chemicals Co., Ltd.), T-1, S-1, S-2000, SP-2 (all manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.) and the like can be used. .

  In the antistatic layer, an organic binder or an inorganic binder can be used as a binder for holding the conductive filler.

  As the organic binder, a resin can be used, and examples thereof include acrylic resins, cycloolefin resins, and polycarbonate resins. Furthermore, as an organic binder, a hard coat can be used as a binder, and an ultraviolet curable polyfunctional acrylic resin, urethane acrylate, epoxy acrylate, oxetane resin, polyfunctional oxetane resin, and the like can be used. Examples of the inorganic binder include inorganic oxide binders (may be inorganic oxide binders using a sol-gel method) and tetrafunctional inorganic binders.

  Preferable examples of the inorganic oxide binder include silicon dioxide, titanium oxide, aluminum oxide, strontium oxide and the like. Particularly preferred is silicon dioxide. Preferred examples of the tetrafunctional inorganic binder include polysilazane (for example, trade name: Aquamica (manufactured by AZ Electronics Co., Ltd.)), siloxane compounds (for example, Colcoat P (manufactured by Colcoat Co., Ltd.)), alkyl silicates and metal alcoholates. Mixing FJ803 (manufactured by GRANDEX), alumina sol (manufactured by Kawaken Fine Chemical Co., Ltd.), and the like can be used. Further, as a tetrafunctional inorganic binder, a sol-gel solution containing tetraethoxysilane as a main raw material and added with a catalyst may be used.

  This antistatic layer can be formed by a conventionally known coating method such as a gravure coating method, a reverse coating method, or a die coating method.

  In addition, it is preferable that the film thickness of an antistatic layer is 100 nm or more and 1 micrometer or less. If the film thickness of the antistatic layer is 100 nm or more, the planarity can be maintained without the conductive filler being lifted from the antistatic layer. Moreover, if the film thickness of the antistatic layer is 1 μm or less, the light transmittance is not deteriorated.

[Gas barrier layer]
In the organic EL device of the present invention, a polysilazane-containing layer containing the quantum dots is provided on a flexible resin substrate, and further, a gas barrier layer and the light emitting member unit are provided in this order on the polysilazane-containing layer. It is a preferable aspect that it is the structure laminated | stacked.

  More specifically, as illustrated in FIG. 1A, it is preferable to form the gas barrier layer 5 between the first electrodes 6 without directly forming the first electrode 6 on the polysilane-containing layer 4 including quantum dots. . As described above, since the polysilazane-containing layer 4 contains particulate quantum dots, the particle pattern is reflected on the surface and has an uneven structure. If the first electrode 6 is formed in such a concavo-convex surface shape, the flatness of the first electrode 6 may be impaired due to the influence of the concavo-convex pattern. In particular, a silver thin-film electrode that is required to have higher-order planarity as the first electrode has a stronger requirement.

  In view of the above problems, in the present invention, before forming the first electrode 6 on the polysilazane-containing layer 4 having a somewhat uneven structure, the gas barrier layer 5 is provided to level the uneven parts. Forming the first electrode after smoothing is preferable in that the first electrode having high planarity can be formed.

  The gas barrier layer forming method according to the present invention includes, as a first method, forming a thin film using a coating solution of polysilazane alone, excluding quantum dots, in the polysilazane-containing layer forming method, and modifying the formed thin film. It is a method of forming a gas barrier layer composed of silicon oxide, silicon nitride or silicon oxynitride by quality treatment, for example, irradiation with vacuum ultraviolet rays. The second method is a method for forming a gas barrier layer by vapor deposition. From the viewpoint of expressing the leveling effect by the gas barrier layer as described above, the first method which is a wet coating method is preferable.

  Here, since the first method is the same as the above-described method for forming the polysilazane-containing layer, it will be omitted, and only the details of the method for forming the gas barrier layer by the vapor deposition method will be described.

(Formation of gas barrier layer by vapor deposition)
When the gas barrier layer 5 is formed on the flexible resin substrate 2 or the polysilazane-containing layer 4 containing quantum dots by the vapor deposition method, applicable vapor deposition methods include physical vapor deposition and chemical vapor deposition. Law.

  The physical vapor deposition method deposits a target substance, for example, a thin film such as a carbon film, on the surface of the flexible resin substrate 2 or the polysilazane-containing layer 4 containing quantum dots in the gas phase by a physical method. These methods include vapor deposition (resistance heating method, electron beam vapor deposition, molecular beam epitaxy) method, ion plating method, sputtering method and the like.

  On the other hand, the chemical vapor deposition method (Chemical Vapor Deposition) is a mixture of a source gas containing components of a target thin film in a gas phase on a polysilazane-containing layer and supplied to the excited discharge gas. In this method, a thin gas barrier layer 5 is deposited on the polysilazane-containing layer by a chemical reaction on the surface of the substrate or in the gas phase. In particular, there is a method of generating plasma etc. for the purpose of activating the chemical reaction. Known CVD methods such as thermal CVD method, catalytic chemical vapor deposition method, photo CVD method, plasma CVD method, atmospheric pressure plasma CVD method, etc. Etc.

  In the present invention, a plasma CVD method or an atmospheric pressure plasma CVD method is preferable as a method for forming the gas barrier layer 5 as a vapor deposition layer on the polysilazane-containing layer 4 containing quantum dots from the viewpoint of film formation speed and processing area.

  The atmospheric pressure or the pressure in the vicinity thereof in the present invention is within a pressure range of 20a to 110 kPa, and is preferably 93 to 104 kPa in order to obtain the good effects described in the present invention. The excited gas as used in the present invention means that at least part of the molecules in the gas move from the existing state to a higher energy state by obtaining energy, and the excited gas molecules, radicalized gas This includes molecules and gas containing ionized gas molecules.

  In the present invention, in the atmospheric pressure plasma CVD method, a method of forming the gas barrier layer 5 containing a metal oxide by an evaporation method is performed in a discharge space where a high-frequency electric field is generated under atmospheric pressure or a pressure in the vicinity thereof. An inorganic film is formed on the polysilazane-containing layer 4 by mixing a source gas containing a metal element with the excited discharge gas to form a secondary excitation gas and exposing the polysilazane-containing layer 4 to the secondary excitation gas. This is a plasma CVD method for forming (ceramic film). That is, the pressure between the counter electrodes (discharge space) is set to atmospheric pressure or a pressure near it, a discharge gas is introduced between the counter electrodes, a high frequency voltage is applied between the counter electrodes, and the discharge gas is changed to a plasma state, and then the plasma state The discharge gas and the raw material gas mixed together are supplied outside the discharge space, and the polysilazane-containing layer is exposed to this mixed gas (secondary excitation gas), and a vapor deposition layer (gas barrier layer) is formed on the polysilazane-containing layer. Form.

  The gas barrier layer 5 containing a metal oxide formed by the plasma CVD method in the present invention may be a composite compound such as a metal oxide, a metal nitride, and a metal carbide.

  The gas barrier layer 5 obtained by the plasma CVD method or the atmospheric pressure plasma CVD method is selected by selecting an organic or inorganic metal compound as a raw material and selecting conditions such as a decomposition gas, a decomposition temperature, and input power. Accordingly, a ceramic film of a metal oxide or a mixture of a metal oxide and a metal carbide, a metal nitride, a metal sulfide, or the like can be appropriately formed. For example, if a silicon compound is used as a raw material compound and oxygen is used as a decomposition gas, a silicon oxide ceramic film is formed. Further, if a zinc compound is used as a raw material compound and carbon disulfide is used as a decomposition gas, a zinc sulfide ceramic film is formed. This is because highly active charged particles and active radicals exist in the plasma space at a high density, so that multistage chemical reactions are accelerated at high speed in the plasma space, and the elements present in the plasma space are thermodynamic. This is because it is converted into an extremely stable compound in a very short time.

  The source gas in the film forming gas used for forming the gas barrier layer 5 according to the present invention can be appropriately selected and used according to the material of the gas barrier layer 5 to be formed. The gas barrier layer preferably contains a reaction product of an organosilicon compound. As such a source gas, for example, an organosilicon compound containing silicon is preferably used.

  Examples of such organosilicon compounds include hexamethyldisiloxane, 1,1,3,3-tetramethyldisiloxane, vinyltrimethylsilane, methyltrimethylsilane, hexamethyldisilane, methylsilane, dimethylsilane, trimethylsilane, diethyl Examples include silane, propylsilane, phenylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, and octamethylcyclotetrasiloxane.

  Among these organosilicon compounds, hexamethyldisiloxane and 1,1,3,3-tetramethyldisiloxane are preferable from the viewpoint of characteristics such as gas barrier properties of the obtained gas barrier layer 5 and handling in film formation. . Moreover, these organosilicon compounds can be used individually by 1 type or in combination of 2 or more types.

  The raw material for such an inorganic film (ceramic film) may be in a gas, liquid, or solid state at normal temperature and pressure. In the case of gas, it can be introduced into the discharge space as it is, but in the case of liquid or solid, it is used after being vaporized by means such as heating, bubbling, decompression or ultrasonic irradiation. Moreover, you may dilute and use by a solvent and can use organic solvents, such as methanol, ethanol, n-hexane, and these mixed solvents. Since these diluted solvents are decomposed into molecular and atomic forms during the plasma discharge treatment, the influence on the film formation can be almost ignored.

  In addition, as a decomposition gas for decomposing a raw material gas containing a metal element to obtain an inorganic compound, hydrogen gas, methane gas, acetylene gas, carbon monoxide gas, carbon dioxide gas, nitrogen gas, ammonia gas, nitrous oxide gas , Nitrogen oxide gas, nitrogen dioxide gas, oxygen gas, water vapor, fluorine gas, hydrogen fluoride, trifluoroalcohol, trifluorotoluene, hydrogen sulfide, sulfur dioxide, carbon disulfide, chlorine gas and the like.

  By appropriately selecting a source gas containing a metal element and a decomposition gas, a ceramic film of a metal oxide or a mixture of a metal oxide and a metal carbide, a metal nitride, a metal halide, a metal sulfide, etc. can be obtained. it can.

  When the gas barrier layer 5 is formed by the vapor deposition method, a discharge gas that tends to be in a plasma state is mixed with the reactive gas of the raw material gas and the decomposition gas, and the mixed gas is sent to the plasma discharge processing apparatus. As such a discharge gas, nitrogen gas and / or 18th group atom of the periodic table, specifically, helium, neon, argon, krypton, xenon, radon, etc. are used. Among these, nitrogen, helium, and argon are preferably used, and nitrogen is particularly preferable because of low cost.

  The gas barrier layer 5 which is a vapor deposition film is formed by supplying a mixed gas obtained by mixing the discharge gas and the reactive gas to the plasma discharge processing apparatus. Although the ratio of the discharge gas and the reactive gas varies depending on the properties of the film to be obtained, it is preferable to supply the reactive gas with the ratio of the discharge gas being 50% or more of the entire mixed gas.

  As described above, various inorganic films (ceramic films) can be formed by using the source gas (reactive gas) as described above together with the discharge gas. In the present invention, the gas barrier layer 5 formed by the vapor deposition method may be composed of a plurality of layers in which these conditions are changed, and the ratio of the discharge gas to the reactive gas and the discharge conditions are continuously set. It may be composed of a changed film that is non-uniform in the film thickness direction.

  Examples of the plasma discharge treatment apparatus that can be applied to the present invention include apparatuses described in Japanese Patent Application Laid-Open Nos. 2004-68143, 2003-49272, and WO 02/48428. .

[Light emitting member unit]
Next, the light emitting member unit U constituting the organic EL element of the present invention will be described.

(First electrode)
In the organic EL element 1 illustrated in FIG. 1, the first electrode 6 is a substantial anode. The organic EL element 1 is a bottom emission type element that passes through the first electrode 6 and extracts light from the flexible resin substrate 2 side. For this reason, the 1st electrode 6 needs to be formed with a translucent conductive layer.

  Here, “translucency” means that the light transmittance at a light wavelength of 550 nm is 50% or more.

As a group of materials that can be used for the first electrode 6, all metal materials that can be used for forming an electrode of an organic EL element can be generally used. Specifically, aluminum, silver, magnesium, lithium, magnesium / same mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO (indium tin oxide ( Indium Tin Oxide (ITO)), ZnO, TiO ₂ , SnO _{2 and} other oxide semiconductors.

  In the organic EL device of the present invention, the first electrode 6 is a layer composed mainly of silver, for example, and is composed of silver or an alloy composed mainly of silver. Preferably there is. As a method for forming the first electrode 6, a method using a wet process such as a coating method, an inkjet method, a coating method, a dipping method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like. And a method using the dry process. Of these, the vapor deposition method is preferably applied.

  As an example, the alloy mainly composed of silver (Ag) constituting the first electrode 6 is silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), silver indium (AgIn). ) And the like.

  The first electrode 6 as described above may have a structure in which silver or an alloy layer mainly composed of silver is divided into a plurality of layers as necessary.

  Further, the first electrode 6 preferably has a thickness in the range of 4 to 12 nm. A thickness of 12 nm or less is preferable because the absorption component and reflection component of the layer are kept low and the light transmittance is maintained. Further, when the thickness is 4 nm or more, the conductivity of the layer is also ensured.

  The first electrode 6 as described above may be covered with a protective film at the top, or may be laminated with another conductive layer. In this case, it is preferable that the protective film and the conductive layer have light transmittance so that the light transmittance of the organic EL element 1 is not impaired.

(Second electrode)
The second electrode 8 is an electrode layer that functions as a cathode for supplying electrons to the organic functional layer unit 7, and a metal, an alloy, an organic or inorganic conductive compound, and a mixture thereof are used. Specifically, gold, aluminum, silver, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO ₂ and oxide semiconductors such as SnO ₂ .

  The second electrode 8 can be formed of these conductive materials by a method such as vapor deposition or sputtering. The sheet resistance as the second electrode 8 is several hundred Ω / sq. The following is preferable, and the thickness is usually selected in the range of 5 nm to 5 μm, preferably 5 to 200 nm.

  In the case where the organic EL element 1 is a double-sided light emitting type in which the emitted light L is also extracted from the second electrode 8 side, the second electrode 6 is configured by selecting a conductive material having good light transmittance. .

(Organic functional layer unit)
The organic functional layer unit 7 can be exemplified by a configuration in which, for example, a hole injection layer / a hole transport layer / a light emitting layer / an electron transport layer / an electron injection layer are stacked in this order on the first electrode 6 that is an anode. Of these, at least, it is necessary to have a light emitting layer composed of an organic material. The hole injection layer and the hole transport layer may be provided as a hole transport / injection layer having a hole transport property and a hole injection property. The electron transport layer and the electron injection layer may be provided as a single layer having electron transport properties and electron injection properties. Of these organic functional layer units 7, for example, the electron injection layer may be made of an inorganic material.

  Further, in addition to these layers, a hole blocking layer, an electron blocking layer, and the like may be stacked on the organic functional layer 7 as necessary. Furthermore, the light emitting layer has each color light emitting layer for generating emitted light in each wavelength region, and a plurality of light emitting layers of each color are laminated through a non-light emitting intermediate layer to form a light emitting layer unit. It may be. The intermediate layer may function as a hole blocking layer and an electron blocking layer.

[Light emitting layer]
The light emitting layer constituting the organic functional layer unit of the organic EL device of the present invention preferably has a structure containing a phosphorescent light emitting compound or a fluorescent light emitting compound as a light emitting material.

  This light emitting layer is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer and holes injected from the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer.

  As such a light emitting layer, there is no restriction | limiting in particular in the structure, if the light emitting material contained satisfy | fills the light emission requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. In this case, it is preferable to have a non-light emitting intermediate layer between the light emitting layers.

  The total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 30 nm because a lower driving voltage can be obtained. In addition, the sum total of the thickness of a light emitting layer is the thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  In the present invention, the thickness of the light emitting layer is preferably adjusted in the range of 1 to 50 nm, more preferably in the range of 1 to 20 nm.

  For the light emitting layer as described above, a light emitting material and a host compound to be described later may be used by publicly known methods such as a vacuum deposition method, a spin coating method, a casting method, an LB method (Langmuir-Blodget, Langmuir Broadgett method), and an ink jet method. Can be formed.

  In the light emitting layer, a plurality of light emitting materials may be mixed, and a phosphorescent light emitting material and a fluorescent light emitting material (also referred to as a fluorescent dopant or a fluorescent compound) may be mixed and used in the same light emitting layer. The structure of the light-emitting layer preferably includes a host compound (also referred to as a light-emitting host) and a light-emitting material (also referred to as a light-emitting dopant compound), and emits light from the light-emitting material.

<Host compound>
As the host compound contained in the light emitting layer, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. Further, the phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As the host compound, a known host compound may be used alone, or a plurality of types of host compounds may be used. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the efficiency of the organic electroluminescent device can be improved. In addition, by using a plurality of kinds of light emitting materials described later, it is possible to mix different light emission, thereby obtaining an arbitrary light emission color.

  The host compound used in the light emitting layer may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). )

  The known host compound is preferably a high Tg (glass transition point) compound that has a hole transporting ability or an electron transporting ability and prevents emission of longer wavelengths. The glass transition point (Tg) here is a value obtained by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

  Examples of host compounds applicable to the present invention include, for example, JP-A Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002 No. -75645, No. 2002-338579, No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002. 363 No. 27, No. 2002-231453, No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-260861, No. 2002-280183. No. 2002, No. 2002-299060, No. 2002-302516, No. 2002-305083, No. 2002-305084, No. 2002-308837, US Patent Publication No. 2003/0175553, US Patent Publication No. 2006/0280965, United States Patent Publication No. 2005/0112407, United States Patent Publication No. 2009/0017330, United States Patent Publication No. 2009/0030202, United States Patent Publication No. 2005/23891 Specification, International Publication No. 2001/039234, International Publication No. 2009/021126, International Publication No. 2008/056746, International Publication No. 2004/093207, International Publication No. 2005/089025, International Publication No. 2007/063796. No., International Publication No. 2007/063754, International Publication No. 2004/107822, International Publication No. 2005/030900, International Publication No. 2006/114966, International Publication No. 2009/086028, International Publication No. 2009/003898, Examples thereof include compounds described in International Publication No. 2012/023947, JP 2008-074939 A, JP 2007-254297 A, EP 2034538, and the like.

<Light emitting material>
Examples of the light-emitting material that can be used in the present invention include phosphorescent compounds (also referred to as phosphorescent compounds or phosphorescent materials) and fluorescent compounds (also referred to as fluorescent compounds or fluorescent materials). It is done.

<Phosphorescent compound>
A phosphorescent compound 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.). Although defined as being a compound of 01 or more, a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in the solution can be measured using various solvents, but when using a phosphorescent compound in the present invention, the phosphorescence quantum yield is 0.01 or more in any solvent. Should be achieved.

  There are two methods as the principle of light emission of the phosphorescent compound. One method is that the carrier recombination occurs on the host compound to which the carrier is transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent compound to transfer the energy from the phosphorescent compound. It is an energy transfer type that obtains luminescence. Another method is a carrier trap type in which a phosphorescent compound serves as a carrier trap, carrier recombination occurs on the phosphorescent compound, and light emission from the phosphorescent compound is obtained. In either case, the condition is that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of a general organic EL device, but preferably contains a group 8-10 metal in the periodic table of elements. More preferred are iridium compounds, more preferred are iridium compounds, osmium compounds, platinum compounds (platinum complex compounds) or rare earth complexes, and most preferred are iridium compounds.

  In the present invention, at least one light emitting layer may contain two or more phosphorescent compounds, and the concentration ratio of the phosphorescent compound in the light emitting layer varies in the thickness direction of the light emitting layer. It may be an embodiment.

  Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

  Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Publication No. 2006006835469, US Patent Publication No. 20060202194, United States Examples include compounds described in Japanese Patent Publication No. 20070087321, US Patent Publication No. 20050246673, and the like.

  Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Publication No. 2002/0034656, US Pat. No. 7,332,232, U.S. Patent Publication No. 20090108737, U.S. Publication No. 20090039776, U.S. Patent No. 6921915, U.S. Patent No. 6,687,266, U.S. Patent Publication No. 20070190359, U.S. Patent Publication No. 2006060008670, U.S. Patent Publication No. 20090165846, United States Patent Publication No. 20080015355, United States Patent No. 7250226, United States Patent No. 7396598, United States Patent Publication No. 20060263635, United States Patent Publication No. 20030138657, U.S. Patent Publication No. 20030152802, may be mentioned compounds described in U.S. Patent No. 7,090,928 Pat like.

  Also, Angew. Chem. lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, United States Patent Publication No. 2006/0251923, United States Patent Publication No. 20050260441, United States Patent No. 7393599, United States Patent No. 7534505, US Pat. No. 7,445,855, US Patent Publication No. 20070190359, US Patent Publication No. 2008097033, US Pat. No. 7,338,722, US Patent Publication No. 20022013 984 Pat, U.S. Pat. No. 7,279,704, U.S. Patent Publication No. 2006098120, compounds described in U.S. Patent Publication No. 2006103874 Pat like can be mentioned.

  Furthermore, International Publication No. 2005/076380, International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339. No., International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, JP2012-069737, JP2009-114086, JP2003-81988, JP2002-302671, JP2002-363552, and the like.

  In the present invention, a preferred phosphorescent dopant includes an organometallic complex having Ir as a central metal. More preferably, a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, or a metal-sulfur bond is preferable.

  The phosphorescent compound described above (also referred to as a phosphorescent metal complex) is described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and methods described as references in these documents are applied. Can be synthesized.

<Fluorescent compound>
Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. And dyes, polythiophene dyes, and rare earth complex phosphors.

[Injection layer: hole injection layer, electron injection layer]
In the present invention, the charge injection layer is a layer provided between the electrode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998) The details are described in Chapter 2, “Electrode Material” (pages 123 to 166) of the second edition of “NTS Co., Ltd.”, and there are a hole injection layer and an electron injection layer.

  In general, the charge injection layer is present between the anode and the light emitting layer or the hole transport layer in the case of a hole injection layer, and between the cathode and the light emitting layer or the electron transport layer in the case of an electron injection layer. However, the present invention is characterized in that the charge injection layer is disposed adjacent to the transparent electrode.

  The hole injection layer according to the present invention is a layer disposed adjacent to the anode, which is a transparent electrode, in order to lower the drive voltage and improve the light emission luminance. The details are described in Volume 2, Chapter 2, “Electrode Materials” (pp. 123-166) of “Month 30th, issued by NTS Corporation”.

  The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of the material used for the hole injection layer include: , Porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives, Inrocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, polyvinylcarbazole, aromatic amines introduced into the main chain or side chain Material or oligomer, polysilane, a conductive polymer or oligomer (e.g., PEDOT (polyethylene dioxythiophene): PSS (polystyrene sulfonic acid), aniline copolymers, polyaniline, polythiophene, etc.) and the like can be mentioned.

  Examples of the triarylamine derivative include benzidine type represented by α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), and MTDATA (4,4 ′, 4 ″). Examples include a starburst type represented by -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine) and a compound having fluorene or anthracene in the triarylamine-linked core.

  In addition, hexaazatriphenylene derivatives such as those described in JP-A-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.

  The electron injection layer is a layer provided between the cathode and the light emitting layer for lowering the driving voltage and improving the light emission luminance. When the cathode is composed of the transparent electrode according to the present invention, Chapter 2 “Electrode materials” (pages 123-166) of the second edition of “Organic EL elements and their forefront of industrialization” (published on November 30, 1998 by NTT) ) Is described in detail.

  The details of the electron injection layer are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. Metals represented by strontium and aluminum, alkali metal compounds represented by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkali metal halide layers represented by magnesium fluoride, calcium fluoride, etc. Examples thereof include an alkaline earth metal compound layer typified by magnesium, a metal oxide typified by molybdenum oxide and aluminum oxide, and a metal complex typified by lithium 8-hydroxyquinolate (abbreviation: Liq).

  The electron injection layer is desirably a very thin film, and although depending on the constituent material, the layer thickness is preferably in the range of 1 nm to 10 μm.

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

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

  Although the above-mentioned thing can be used as a positive hole transport material, It is preferable to use a porphyrin compound, an aromatic tertiary amine compound, and a styryl amine compound, especially an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl, N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (abbreviation: 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 -Tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, '-Di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) c Audriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N- Examples include diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4′-N, N-diphenylaminostilbenzene, N-phenylcarbazole and the like.

  Further, those having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino ] Biphenyl (abbreviation: NPD), 4,4 ′, 4 ″ -tris [N- (3-methyl) in which triphenylamine units described in JP-A-4-308688 are linked in a three star burst type Phenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

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

  For the hole transport layer, known methods such as vacuum deposition, spin coating, casting, printing including ink jet, and LB (Langmuir Brodget, Langmuir Broadgett) are used as the hole transport material. Thus, it can be formed by thinning. Although there is no restriction | limiting in particular about the layer thickness of a positive hole transport layer, Usually, about 5 nm-5 micrometers, Preferably it is the range of 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Moreover, p property can also be made high by doping the material of a positive hole transport layer with an impurity. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175 and J.P. Appl. Phys. 95, 5773 (2004), and the like.

  Thus, it is preferable to increase the p property of the hole transport layer because an element with lower power consumption can be manufactured.

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

  In the electron transport layer having a single-layer structure and the electron transport layer having a multilayer structure, an electron transport material (also serving as a hole blocking material) constituting a layer portion adjacent to the light emitting layer is used as an electron transporting material. What is necessary is just to have the function to transmit. As such a material, any one of conventionally known compounds can be selected and used. Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as a material for the electron transport layer it can. Furthermore, a polymer material in which these materials are introduced into a polymer chain, or a polymer material having these materials as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (abbreviation: 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 (abbreviation: Znq), etc. and the central metal of these metal complexes A metal complex replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as a material for the electron transport layer.

  In addition, metal-free or metal phthalocyanine or those having terminal ends substituted with alkyl groups or sulfonic acid groups can be preferably used as the material for the electron transport layer. In addition, distyrylpyrazine derivatives exemplified as the material of the light emitting layer can also be used as the material of the electron transport layer. Like the hole injection layer and the hole transport layer, n-type-Si, n-type-SiC, etc. These inorganic semiconductors can also be used as a material for the electron transport layer.

  The electron transport layer can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, and an LB method. Although there is no restriction | limiting in particular about the layer thickness of an electron carrying layer, Usually, about 5 nm-5 micrometers, Preferably it exists in the range of 5-200 nm. The electron transport layer may have a single structure composed of one or more of the above materials.

  In addition, the electron transport layer can be doped with impurities to increase the n property. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175 and J.P. Appl. Phys. 95, 5773 (2004), and the like. Furthermore, it is preferable to contain potassium, a potassium compound, etc. in an electron carrying layer. As the potassium compound, for example, potassium fluoride can be used. Thus, by increasing the n property of the electron transport layer, an organic EL element with lower power consumption can be obtained.

[Blocking layer: hole blocking layer, electron blocking layer]
The blocking layer includes a hole blocking layer and an electron blocking layer, and is a layer provided as necessary in addition to the constituent layers of the organic functional layer unit 7 described above. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). Hole blocking (hole block) layer and the like.

  The hole blocking layer has a function of an electron transport layer in a broad sense. The hole blocking layer is made of a hole blocking material that has a function of transporting electrons but has a very small ability to transport holes, and recombines electrons and holes by blocking holes while transporting electrons. Probability can be improved. Moreover, the structure of an electron carrying layer can be used as a hole-blocking layer as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. The electron blocking layer is made of a material that has the ability to transport holes and has a very small ability to transport electrons. By blocking holes while transporting holes, the probability of recombination of electrons and holes is improved. Can be made. Moreover, the structure of a positive hole transport layer can be used as an electron blocking layer as needed. The layer thickness of the hole blocking layer applied to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

[Sealing member]
The sealing member 9 covers the organic EL element, and the plate-like (film-like) sealing member 9 is fixed to the second electrode 8 side by the sealing resin layer. The sealing member 9 is provided in a state of covering at least the organic functional layer unit 7 and is provided in a state of exposing the organic EL element and the terminal portion (not shown) of the second electrode 8. Moreover, an electrode may be provided on the sealing member 9 so that the terminal portion of the organic EL element and the second electrode 8 is electrically connected to the electrode.

  Specific examples of the plate-like (film-like) sealing member 9 include a flexible glass substrate and a polymer substrate. These substrate materials may be used in the form of a thin film. Examples of the glass substrate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer substrate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

  Especially, since the organic EL element can be thinned, a polymer substrate in the form of a thin film can be preferably used as the sealing member 9.

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

  Further, the above substrate material may be processed into a concave plate shape and used as the sealing member 9. In this case, the above-described substrate member is subjected to processing such as sand blasting or chemical etching to form a concave shape.

  Further, the present invention is not limited to this, and a flexible metal material may be used. Examples of the metal material include 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. By using such a metal material as a sealing member 9 in the form of a thin film, the entire light-emitting panel provided with the organic EL element 1 can be thinned.

[Sealing resin layer]
Specifically, the sealing resin layer (also referred to as an adhesive layer) for fixing the sealing member to the second electrode 8 side is a light having a reactive vinyl group such as an acrylic acid oligomer or a methacrylic acid oligomer. Examples include curable and thermosetting adhesives and moisture curable adhesives such as 2-cyanoacrylate. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

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

[Other component layers]
In the organic EL device of the present invention, in addition to the above-described constituent layers, if necessary, nitrogen atoms or sulfur atoms are provided below the anchor coat layer, the smooth layer, the bleed-out prevention layer, and the silver electrode layer. An underlayer containing the same may be provided.

<< Application field of organic EL elements >>
Since the organic electroluminescent element of the present invention is a surface light emitter as described above, it can be used as various light sources. For example, lighting devices such as home lighting and interior lighting, backlights for clocks and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, Examples include a light source of an optical sensor. Moreover, it is not limited to these light emission light sources, It can use also as another light source.

  In particular, 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 addition, the organic electroluminescence element of each embodiment may be used as a kind of lamp for illumination or an exposure light source, a projection device that projects an image, and a still image or a moving image is directly visually recognized. It may be used as a type of display device (display). In this case, with the recent increase in the size of lighting devices and displays, the light emitting surface may be enlarged by so-called tiling, in which light emitting panels provided with organic electroluminescence elements are joined together in a plane.

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. A color or full-color display device can be manufactured by using two or more kinds of organic electroluminescence elements having different emission colors.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

《Preparation of quantum dots》
[Preparation of quantum dots A]
Under an argon stream, 7.5 g of tri-n-octylphosphine oxide (TOPO) (manufactured by Kanto Chemical Co.), 2.9 g of stearic acid (manufactured by Kanto Chemical Co., Ltd.), 620 mg of n-tetradecylphosphonic acid (manufactured by AVOCADO) Then, 250 mg of cadmium oxide (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the mixture was heated and mixed at 370 ° C. After naturally cooling this to 270 ° C., a solution in which 200 mg of selenium (manufactured by STREMCHEMICAL) was dissolved in 2.5 ml of tributylphosphine (manufactured by Kanto Chemical Co., Inc.) was added in advance, dried under reduced pressure, and CdSe coated with TOPO. Fine particles were obtained.

  Next, 15 g of TOPO was added to the obtained CdSe fine particles and heated, and subsequently, a solution of 1.1 g of zinc diethyldithiocarbamate (manufactured by Tokyo Chemical Industry Co., Ltd.) dissolved in 10 ml of trioctylphosphine (manufactured by Sigma Aldrich) at 270 ° C. was added. Quantum dots A (average particle size: 12 nm) having CdSe nanocrystals (average particle size of 2 nm) as the core and ZnS as the shell with TOPO fixed on the surface were prepared. In addition, the average particle diameter of the quantum dot A was measured using the particle size measuring apparatus (The product made by Malvern, "ZETASIZER Nano Series Nano-ZS") by the dynamic light scattering method.

[Preparation of quantum dots B]
In the preparation of the quantum dot A, a quantum dot B having a CdCe nanocrystal (average particle diameter of 2 nm) as a core and ZnS as a shell is used except that cerium is used instead of selenium during core particle formation. (Average particle diameter: 12 nm) was prepared.

[Preparation of quantum dots C]
In the preparation of the quantum dots A, quantum dots C (average particle diameter: 6 nm) having a CdSe nanocrystal (average particle diameter of 2 nm) as a core and ZnS as a shell are the same except that the formation conditions at the time of shelling are changed. ) Was prepared.

[Preparation of quantum dots D: surface coating with TEOS]
In the preparation of the quantum dots A, quantum dots D (average particle diameter: 2 nm) were prepared only as a core part which is a CdSe nanocrystal (average particle diameter: 2 nm).

[Preparation of quantum dots E]
40 ml of the above quantum dot A solution (containing 11 g of quantum dots) was dried under vacuum. Thereafter, 60 ml of tetraethyl orthosilicate (tetraethoxysilane, TEOS) was added to disperse the quantum dots A and incubated overnight under N ₂ atmosphere. The dispersion was then poured into a 1 L inverse microemulsion (cyclohexane / CO-520, 1800 ml / 135 g) in a 5 L flask with stirring at 600 rpm. After the mixture was stirred for 15 minutes, 010 ml of 4% NH ₄ OH was added to initiate the reaction. The next day, the reaction was stopped by centrifugation and the solid phase was collected. The obtained particles were washed twice with 2 L of cyclohexane and then dried under vacuum to prepare quantum dots E having a particle surface coated with TEOS and an average particle diameter of 15 nm.

<< Production of organic EL element >>
[Production of Organic EL Element 1]
According to the following method, the organic EL element 1 having the configuration shown in (a) of Table 1 was produced. In addition, the number in () respond | corresponds to the code number of each component described in (a) of Table 1.

(1) Preparation of flexible resin base material (2) As a flexible resin base material (2), a 125 μm thick polyester film (manufactured by Teijin DuPont Films Ltd., polyethylene terephthalate, KDL86WA) that is easily bonded on both sides Hereinafter, abbreviated as PET film 1).

The surface of the PET film 1 was subjected to corona treatment using a corona discharge device AGI-080 (manufactured by Kasuga Denki Co.). During the corona treatment, the gap between the discharge electrode of the corona discharge device and the surface of the film was set to 1 mm, and the treatment output was 600 mW / cm ² , and a corona discharge was performed for 10 seconds.

(2) Formation of antistatic layer (3) Next, the following antistatic layer forming coating solution was used on the back side of PET film 1 (the side opposite to the side on which the polysilazane-containing layer described later is formed). Then, an antistatic layer (3) was formed as a backcoat layer.

(Preparation of coating solution for forming antistatic layer)
14 parts of colcoat P (manufactured by Colcoat Co.), which is a siloxane-based material as an inorganic binder, 85 parts of phosphorus-doped tin oxide Cellux CX-S501M (manufactured by Nissan Chemical Industries, Ltd.) as an inorganic double oxide, and BYK3550 (Big Chemie) as a leveling agent Japan Co., Ltd.) was mixed with stirring to prepare a coating solution for forming an antistatic layer.

(Application of antistatic layer)
By applying the prepared coating solution for forming an antistatic layer on the back side of the PET film using a wet coater so that the film thickness after drying is 300 nm, and then drying at 80 ° C. for 10 seconds. Then, an antistatic layer (3) was formed.

(3) Formation of polysilazane-containing layer (4) (Preparation of coating liquid 1 for forming a polysilazane-containing layer)
Disperse 5.00 mg of the above quantum dot A in a toluene solvent, and further add perhydropolysilazane (Aquamica NN120-10, non-catalytic type, manufactured by AZ Electronic Materials Co., Ltd., abbreviation: PHPS). A coating liquid 1 for forming a polysilazane-containing layer in which the A content was 1.0% by mass was prepared.

(Application of polysilazane-containing layer)
The prepared polysilazane-containing layer-forming coating solution 1 is applied to the surface side of the flexible resin substrate PET film 1 using a wet bar coater under the condition that the dry film thickness is 5 μm. The polysilazane-containing layer (4) was formed by drying at 1 ° C. for 1 minute.

(Modification treatment of polysilazane-containing layer (4))
Next, the formed polysilazane-containing layer (4) was subjected to a modification treatment according to a vacuum ultraviolet irradiation method using the following excimer apparatus.

<Excimer irradiation system>
Apparatus: M.com Co., Ltd. excimer irradiation apparatus MODEL: MECL-M-1-200
Irradiation wavelength: 172 nm Lamp enclosed gas: Xe
<Reforming treatment conditions>
The flexible resin base material on which the polysilazane-containing layer fixed on the operation stage was formed was subjected to a modification treatment under the following conditions.

Excimer lamp light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 1mm
Stage heating temperature: 70 ° C
Oxygen concentration in the irradiation device: 0.01%
Excimer lamp irradiation time: 5 seconds.

(4) Formation of gas barrier layer (5) Next, a 10% by mass dibutyl ether solution of perhydropolysilazane (supra: Aquamica NN120-10, AZ Electronic Materials Co., Ltd., PHPS) and amine catalyst N, Using a wet bar coater, a coating solution for forming a gas barrier layer, in which a 10% by mass dibutyl ether solution of N, N ′, N′-tetramethyl-1,6-diaminohexane was mixed at a ratio of 99: 1, It was applied on the polysilazane-containing layer (4) formed above under the condition that the (average) film thickness after drying was 250 nm, and dried for 1 minute with dry air at a temperature of 50 ° C. and a dew point of −5 ° C. Then, it was treated with dry air at a temperature of 95 ° C. and a dew point of −5 ° C. for 2 minutes to form a polysilazane precursor layer.

<Modification treatment of polysilazane precursor layer>
The surface of the formed polysilazane precursor layer is subjected to a modification treatment (excimer light irradiation treatment) by applying a vacuum ultraviolet irradiation method using an excimer apparatus similar to that used in the formation of the polysilazane-containing layer, and a gas barrier layer ( 5) was formed.

(5) Formation of first electrode (6) On the gas barrier layer formed above, a first electrode composed of a base layer (not shown in FIG. 1) and a silver thin film electrode was formed according to the following method.

  The flexible resin base material on which the gas barrier layer (5) is formed is fixed to a base material holder of a commercially available vacuum deposition apparatus, and the following compound N is put in a resistance heating boat made of tungsten and heated with these base material holders. The boat was attached to the first vacuum chamber of the vacuum deposition apparatus. Moreover, silver (Ag) was put into the resistance heating boat made from tungsten, and it attached in the 2nd vacuum chamber of a vacuum evaporation system.

Next, after depressurizing the first vacuum chamber of the vacuum deposition apparatus to 4 × 10 ⁻⁴ Pa, the heating boat containing the compound N was heated by energization, and the deposition rate was 0.1 nm / second to 0.2 nm / second. The underlayer of the first electrode was provided with a thickness of 10 nm.

Next, the flexible resin base material formed up to the base layer is transferred to the second vacuum tank while being vacuumed, and after the pressure of the second vacuum tank is reduced to 4 × 10 ⁻⁴ Pa, the heating boat containing silver is energized. And heated. Thus, a first electrode made of silver having a thickness of 8 nm was formed at a deposition rate of 0.1 nm / second to 0.2 nm / second.

(6) Formation of organic functional layer unit (7) to second electrode (8) Subsequently, using a commercially available vacuum deposition apparatus, the pressure is reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa and then formed to the first electrode (6). While moving the flexible resin substrate, the compound HT-1 was deposited at a deposition rate of 0.1 nm / second to provide a 20 nm hole transport layer (HTL).

  Next, compound A-3 (blue light emitting dopant), compound A-1 (green light emitting dopant), compound A-2 (red light emitting dopant) and compound H-1 (host compound), compound A-3 having a film thickness In contrast, the vapor deposition rate was changed depending on the location so that it was linearly 35% by mass to 5% by mass, and the compound A-1 and the compound A-2 each had a concentration of 0.2% by mass without depending on the film thickness. Thus, at a deposition rate of 0.0002 nm / sec, the compound H-1 was co-deposited so that the total thickness would be 70 nm by changing the deposition rate depending on the location so that 64.6% to 94.6% by mass. A light emitting layer was formed.

  Thereafter, Compound ET-1 was deposited to a thickness of 30 nm to form an electron transport layer, and potassium fluoride (KF) was further formed to a thickness of 2 nm. Furthermore, aluminum 110nm was vapor-deposited and the 2nd electrode (8) was formed.

  In addition, the said compound HT-1, compound A-1 to 3, compound H-1, and compound ET-1 are the compounds shown below.

(7) Solid sealing Next, a 100 μm thick aluminum foil is used as the sealing member (9), and a thermosetting liquid adhesive (epoxy resin) is used as a sealing resin layer on one surface of the aluminum foil. The sealing member (9) bonded with a thickness of 30 μm was used to superimpose the sample formed up to the second electrode (8). At this time, the adhesive forming surface of the sealing member (9) and the organic EL element (1) are organic so that the ends of the lead electrodes of the first electrode (6) and the second electrode (8) are exposed. The surface of the functional layer unit (7) was continuously superposed.

  Next, the laminated body is placed in a decompression device, and the sample and the sealing member formed between the flexible resin base material and the second electrode overlapped at 90 ° C. under a decompression condition of 0.1 MPa. Pressed and held for 5 minutes. Subsequently, the laminate was returned to the atmospheric pressure environment and further heated at 90 ° C. for 30 minutes to cure the adhesive.

  The sealing step is performed under atmospheric pressure and in a nitrogen atmosphere with a moisture content of 1 ppm or less, in accordance with JIS B 9920, with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or less, and an oxygen concentration of 0.8 ppm or less. At atmospheric pressure. In addition, the description regarding formation of the extraction wiring etc. from the 1st electrode (6) and the 2nd electrode (8) is abbreviate | omitted.

  Thus, a white light emitting organic EL element 1 was produced.

[Production of Organic EL Element 2]
In the production of the organic EL element 1, the arrangement of the polysilazane-containing layer and the gas barrier layer was changed, and the organic EL element 2 was produced in the same manner except that the configuration shown in FIG.

[Production of Organic EL Element 3]
In the production of the organic EL element 1, the organic EL element 3 was similarly formed except that the arrangement position of the polysilazane-containing layer was changed to the back side of the flexible resin substrate as shown in FIG. Was made.

[Production of organic EL elements 4 to 6]
In the production of the organic EL element 1, organic EL elements 4 to 6 were produced in the same manner except that the quantum dots applied to the polysilazane-containing layer were changed from quantum dots A to quantum dots B to D, respectively.

[Production of Organic EL Element 7]
In the formation of the polysilazane-containing layer of the organic EL element 1, an organic EL element was used except that vacuum ultraviolet treatment was not performed, and only drying was performed at 80 ° C. for 1 minute in the same drying step as the production of the organic EL element 1. The organic EL element 7 was produced in the same manner as in 1.

[Production of Organic EL Element 8]
In the formation of the polysilazane-containing layer of the organic EL element 1, as a modification treatment method, in the same manner as the production of the organic EL element 1 except that a heat treatment was performed at 120 ° C. for 1 minute instead of the vacuum ultraviolet treatment. An organic EL element 8 was produced.

[Production of Organic EL Element 9]
In the production of the organic EL element 1, the organic EL element 9 was formed in the same manner except that the gas barrier layer was formed by the following plasma CVD method instead of the formation method using perhydropolysilazane and vacuum ultraviolet rays. Produced.

(Plasma CVD method)
A gas barrier layer made of SiO ₂ and having a thickness of 250 nm was formed on the surface of the polysilazane-containing layer using the plasma CVD apparatus described in JP-A-2007-307784, according to the following film forming conditions.

<Film formation conditions>
Feed rate of source gas (hexamethyldisiloxane, HMDSO): 50 sccm (Standard Cubic Centimeter per Minute)
Supply amount of oxygen gas (O ₂ ): 500 sccm
Degree of vacuum in the vacuum chamber: 3Pa
Applied power from the power source for plasma generation: 0.5 kW
Frequency of power source for plasma generation: 13.56 MHz
Conveying speed of flexible resin substrate: 0.5 m / min
[Production of Organic EL Element 10]
In the production of the organic EL element 1, a biaxially stretched polyethylene naphthalate film (abbreviation: PEN, thickness: 125 μm, manufactured by Teijin DuPont Films) was used in place of the PET film 1 as the flexible resin base material. Except for the above, an organic EL element 10 was produced in the same manner.

[Production of Organic EL Element 11]
In the production of the organic EL element 1, the organic EL element 11 was produced in the same manner except that the first electrode was changed to the ITO electrode described below and the underlayer was removed.

(Formation of the first electrode from ITO)
On the gas barrier layer of the organic EL element 1, an ITO (indium-tin composite oxide) film having a thickness of 120 nm is formed by sputtering, patterned by photolithography, and a first electrode layer (anode). Formed.

[Production of Organic EL Element 12]
In the production of the organic EL element 1, an organic EL element 12 was produced in the same manner except that the polysilazane-containing layer was changed by the method described below.

(Formation of polysilazane-containing layer)
<Preparation of coating solution for forming polysilazane-containing layer>
A coating solution for forming a polysilazane-containing layer was prepared by dispersing 5.00 mg of the quantum dots A in a toluene solvent, adding a PMMA resin solution, and setting the content of the quantum dots A to the PMMA resin to 1.0 mass%.

(Application of polysilazane-containing layer)
The prepared polysilazane-containing layer forming coating solution is applied to the surface side of the flexible resin substrate PET film 1 using a wet bar coater so as to have a dry film thickness of 80 μm. It was dried for a minute to form a polysilazane-containing layer.

(Modification treatment of polysilazane-containing layer)
Next, the polysilazane-containing layer thus formed was subjected to a modification treatment by irradiating it with vacuum ultraviolet rays using the same excimer apparatus used for the production of the organic EL element 1.

[Production of Organic EL Element 13]
In the production of the organic EL element 12, in place of the PMMA resin solution used for forming the polysilazane-containing layer, Irgacure 184 (BASF) was used as a photopolymerization initiator in a UV curable resin Unidic V-4025 manufactured by DIC Corporation. Organic EL element 13 was produced in the same manner except that a UV curable resin solution prepared by adjusting the solid content ratio (mass%) to be resin / initiator: 95/5 was used.

[Production of Organic EL Element 14]
In the production of the organic EL element 12, the organic EL element 14 was produced in the same manner except that the quantum dot E in which the particle surface was coated with TEOS was used instead of the quantum dot A used for forming the polysilazane-containing layer. .

[Production of Organic EL Element 15]
In the production of the organic EL element 1, an organic EL element 15 was produced in the same manner except that the polysilazane-containing layer was removed.

  Table 1 shows details of each organic EL element fabricated as described above.

  In addition, the detail of the component described with the abbreviation in Table 1 is as follows.

PET: Polyethylene terephthalate PEN: Polyethylene naphthalate TEOS: Tetraethoxysilane PHPS: Perhydropolysilazane PMMA: Polymethyl methacrylate HMDSO: Hexamethyldisiloxane Further, regarding the neutral region, JP-A-2005-251671 and JP-A-2006 After obtaining the neutral plane according to the method for obtaining the neutral plane described in Japanese Patent No. 58764, the layer thickness D of the organic EL element is obtained, and a region of D ± 10% from the neutral plane is obtained as the neutral region. It was.

<< Evaluation of organic EL elements >>
[Evaluation of color rendering properties]
Each organic EL element was applied at room temperature (25 ° C.) under the condition that the emission luminance was 1000 cd / m ^2, and the spectral distribution characteristics were measured using a spectral radiance meter CS-2000 (manufactured by Konica Minolta). The color rendering index Ra was determined according to the color rendering property evaluation method of the light source specified in JIS-Z-8726 (1990), and the color rendering property was evaluated according to the following criteria.

5: Color rendering index Ra is 90 or more 4: Color rendering index Ra is 80 or more and less than 90 3: Color rendering index Ra is 70 or more and less than 80 2: Color rendering index Ra is 60 or more and less than 70 1: Color rendering index Ra is less than 60 [Durability Evaluation]
(Preparation of bent sample)
Each organic EL element is wound around a plastic roller having a diameter of 10 mm under an environment of 25 ° C. and 20% RH, with the surface side of the organic EL element (the surface having the siloxane-containing layer) outside, and then the back side is It wound so that it might become an outer side, and this front and back surface winding operation was repeated 100 times, and the bent sample was produced.

(Forced deterioration processing)
Next, the untreated sample and the sample subjected to the bending treatment by the above method were subjected to a forced degradation treatment for 500 hours in an environment of 85 ° C. and 85% RH.

(Evaluation of color rendering)
The color rendering properties after the forced deterioration treatment were evaluated by the above method and the evaluation rank for the sample that was subjected to the forced deterioration treatment and was not subjected to the bending treatment and the sample that was subjected to the bending treatment.
The results obtained as described above are shown in Table 2.

  As is clear from the results shown in Table 2, the organic EL device in which the polysilazane-containing layer containing the quantum dots defined in the present invention was arranged on the light extraction side was subjected to color rendering and bending treatment relative to the comparative example. It turns out that the effect excellent in later durability (color rendering property) is exhibited.

  Specifically, when the organic EL element 1 and the organic EL element 15 of the present invention are compared, by providing a polysilazane-containing layer containing quantum dots on the light extraction side, color rendering properties and durability after being subjected to bending treatment (color rendering properties) ) Is dramatically improved.

  Further, when the organic EL element 1 of the present invention is compared with the organic EL elements 12 to 14 which are comparative examples, the layer containing quantum dots is composed of polysilazane or a modified polysilazane, thereby rendering the color rendering property and bending treatment. It can be seen that the durability (color rendering property) after the treatment is improved.

  Next, each effect between the organic EL elements of the present invention will be described.

  As the position of the polysilazane-containing layer in the organic EL device of the present invention, the organic EL device 1 having the configuration shown in FIG. 1A, the organic EL device 2 having the configuration shown in FIG. Comparing each effect of the organic EL element 3 having the configuration shown in (c), the organic EL element 1 and the organic EL element 2 having the polysilazane-containing layer in the neutral region where the tensile stress and the compressive stress are minimum values are as follows. It can be seen that the organic EL element 3 provided with a polysilazane-containing layer outside the neutral region in the outermost layer is more excellent in color rendering and durability (color rendering) after being bent.

  Further, a micro loam is used for the organic EL element 1 having a gas barrier layer as a buffer layer between the polysilazane-containing layer and the first electrode, and the organic EL element 2 in which the polysilazane-containing layer and the first electrode are in direct contact. As a result of cutting out each section and comparing the smoothness of the first electrode with a scanning electron microscope for the section, the organic EL element 1 having a gas barrier layer as a buffer layer in the middle is more suitable for the first electrode. It was confirmed that the smoothness was excellent.

  Further, as a method for modifying the formed polysilazane-containing layer, the organic EL element 7 which has been partially modified only by the drying process at the time of forming the polysilazane-containing layer is further modified by heat treatment after the coating film is formed. It can be seen that the durability (color rendering property) after the color rendering property and the bending treatment are improved in the order of the organic EL device 8 subjected to the above, and further the organic EL device 1 subjected to the vacuum ultraviolet irradiation treatment with excimer light. .

  Furthermore, the gas barrier layer is vacuum-treated using polysilazane for the organic EL element 9 formed by plasma CVD using HMDSO or the organic EL element 11 formed of an ITO electrode as the first electrode. It can be seen that the organic EL element formed by ultraviolet irradiation and using the silver thin film electrode as the first electrode exhibits a more excellent effect.

1 Organic electroluminescence device (organic EL device)
2 Flexible resin base material 3 Back coat layer (antistatic layer)
4 Polysilazane-containing layer 5 Gas barrier layer 6 First electrode 7 Organic functional layer unit 8 Second electrode 9 Sealing member C Compressive force CS: Compressive stress D Total film thickness F Bending force L Light emission (light extraction side)
QD Quantum dot T Tensile force TS Tensile stress U Light emitting member unit

Claims (9)

Organic electroluminescence having a light emitting member unit composed of a pair of electrodes disposed at least on opposing positions on a flexible resin substrate and an organic functional layer group including a light emitting layer sandwiched between the electrodes. An element,
An organic electroluminescence device comprising a polysilazane-containing layer containing quantum dots on the light extraction side.   The organic electroluminescence device according to claim 1, wherein the polysilazane-containing layer including the quantum dots is located in a neutral region of stress when the organic electroluminescence device receives a bending moment.   The organic electroluminescence device according to claim 1 or 2, wherein the polysilazane-containing layer containing the quantum dots is a layer containing a modified polysilazane modified body.   The organic electroluminescence device according to claim 3, wherein the modification treatment for the polysilazane-containing layer is a modification method using vacuum ultraviolet irradiation.   5. The polysilazane-containing layer containing the quantum dots is disposed between the flexible resin base material and the light emitting member unit. 6. The organic electroluminescent element of description.   It has a polysilazane-containing layer containing the quantum dots on the flexible resin substrate, and further, a gas barrier layer and the light emitting member unit are laminated in this order on the polysilazane-containing layer. The organic electroluminescent element according to any one of claims 1 to 5. The quantum dot is composed of at least Si, Ge, GaN, GaP, CdS, CdSe, CdTe, InP, InN, ZnS, In ₂ S ₃ , ZnO, CdO, or a mixture thereof. The organic electroluminescent element according to any one of claims 1 to 6.   8. The organic electroluminescence device according to claim 1, wherein the quantum dot has a core / shell structure or a gradient structure formed of at least two kinds of compounds. 9.   9. The electrode according to claim 1, wherein at least one of the pair of electrodes facing each other and the electrode disposed on the light extraction side is an electrode mainly composed of silver. The organic electroluminescent element according to claim 1.

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