JP4742620B2 - LIGHT EMITTING ELEMENT, LIGHT EMITTING DEVICE, AND ELECTRONIC DEVICE - Google Patents

Description

  The present invention relates to a light emitting element, a light emitting device, and an electronic apparatus.

An organic electroluminescent element (light emitting element) having a structure in which at least one light emitting organic layer (organic electroluminescent layer) is sandwiched between a cathode and an anode can significantly reduce the applied voltage compared to an inorganic EL element. In addition, various light emitting elements can be manufactured (see, for example, Non-Patent Documents 1 to 3 and Patent Documents 1 to 3).
At present, in order to obtain a higher performance organic EL element, various device structures including material development and improvement have been proposed, and active research is being conducted.

In addition, for this organic EL element, various luminescent color elements, high luminance and high efficiency elements have already been developed, and there are various practical applications such as use as a pixel of a display device and use as a light source. It is being considered.
Various researches have been conducted with the aim of further improving luminous efficiency and durability (lifetime) for practical application.

Appl.Phys.Lett.51 (12), 21 September 1987, p.913 Appl.Phys.Lett.71 (1), 7 July 1997, p.34 Nature 357,477 1992 JP-A-10-153967 Japanese Patent Laid-Open No. 10-12377 Japanese Patent Laid-Open No. 11-40358

  An object of the present invention is to provide a light-emitting element in which light emission from a light-emitting layer can be visually recognized from the cathode side, and excellent in luminous efficiency and durability (lifetime), and a highly reliable light-emitting device and electronic apparatus including the light-emitting element. It is to provide.

Such an object is achieved by the present invention described below.
The light-emitting device of the present invention includes a cathode mainly composed of a transparent conductive oxide, an anode, and an electron transport layer, a light-emitting layer, and a hole transport layer from the cathode side between the cathode and the anode. Further, a light-emitting element in which a barrier layer is provided between the electron transport layer and the cathode, and the light-emitting layer emits light by energizing the cathode and the anode,
The electron transport layer is porous and mainly composed of an inorganic semiconductor material,
The barrier layer is provided in contact with the electron transport layer, and the porosity thereof is smaller than the porosity of the electron transport layer, and is made of a material having the same composition as the material constituting the electron transport layer. ,
The light emission is configured to be viewed from the cathode side.
Thereby, the light emitting element which can visually recognize the light emission of the light emitting layer from the cathode side and is excellent in light emission efficiency and durability (lifetime) can be obtained.
In addition, more trap levels are formed in the electron transport layer, and electrons are more efficiently transported through the trap levels.
In addition, it is possible to increase the formation region of the light emitting layer, that is, increase the amount (adsorption amount) of the light emitting material to the electron transport layer.
Moreover, it can prevent or suppress more reliably that a positive hole transport layer contacts a cathode. Further, the barrier layer having such a configuration has an advantage that it can be formed relatively easily.

In the light-emitting device of the present invention, the barrier layer, and Turkey the hole transport layer to have a preventing or inhibiting function to contact with the cathode via the electron transport layer.
By providing a bus rear layer, in the light-emitting element over time short circuit occurs, the emission efficiency is prevented from lowering, i.e., it is possible to improve the durability (life).

In the light emitting device of the present invention, when the porosity of the barrier layer is A [%] and the porosity of the electron transport layer is B [%], B / A is 1.1 or more. preferable.
Thereby, the barrier layer can more reliably prevent or suppress contact between the hole transport layer and the cathode.
In the light emitting device of the present invention, the barrier layer preferably has a porosity of 20% or less.
Thereby, the effect of preventing or suppressing contact between the hole transport layer and the cathode can be further improved.

In the light emitting device of the present invention, the thickness ratio between the barrier layer and the electron transport layer is preferably 1:99 to 60:40.
Thereby, the barrier layer can more reliably prevent or suppress contact between the hole transport layer and the cathode.
In the light emitting device of the present invention, the barrier layer preferably has an average thickness of 1 μm or less.
Thereby, the effect of preventing or suppressing contact between the hole transport layer and the cathode can be further improved.

In the light emitting device of the present invention, the barrier layer preferably has an electrical conductivity equivalent to that of the electron transport layer.
As a result, electrons are smoothly transferred between the barrier layer and the electron transport layer.
In the light emitting device of the present invention, the barrier layer is preferably formed by a MOD method.
According to the MOD method, the reaction of the precursor of the constituent material of the barrier layer (for example, hydrolysis, polycondensation, etc.) is prevented in the barrier layer forming material, so that the barrier layer can be more easily and reliably (reproduced). Can be formed). Further, the obtained barrier layer can be dense (with a porosity within the above range).

In the light emitting device of the present invention, it is preferable that a resistance value in a thickness direction of the entire barrier layer and the electron transport layer is 100 Ω / cm ² or more.
Thereby, the leak (short circuit) between a positive hole transport layer and an electrode can be prevented or suppressed more reliably, and the further improvement of durability (life) of a light emitting element can be aimed at.
In the light emitting device of the present invention, the barrier layer is preferably located between the cathode and the electron transport layer.
Thereby, the barrier layer can more reliably prevent or suppress contact between the hole transport layer and the cathode.

In the light emitting device of the present invention, the interface between the barrier layer and the electron transport layer is preferably unclear.
As a result, the transfer of electrons between the barrier layer and the electron transport layer is performed more reliably (efficiently).
In the light emitting device of the present invention, it is preferable that the barrier layer and the electron transport layer are integrally formed.
As a result, the transfer of electrons between the barrier layer and the electron transport layer is performed more reliably (efficiently).
In the light emitting device of the present invention, it is preferable that a part of the electron transport layer functions as the barrier layer.
As a result, the transfer of electrons between the barrier layer and the electron transport layer is performed more reliably (efficiently).

In the light emitting device of the present invention, the electron transport layer preferably has a porosity of 20 to 75%.
As a result, while preventing the mechanical strength of the electron transport layer from decreasing, more light-emitting materials can be attached to the electron transport layer, and in the case of providing a hole transport layer, hole transport is possible. The layer can penetrate deeper into the electron transport layer.

In the light emitting device of the present invention, the electron transport layer preferably has an average thickness of 1 to 50 μm.
Thereby, it is possible to reduce the thickness of the light emitting element while preventing the mechanical strength (film strength) of the electron transport layer from decreasing.
In the light emitting device of the present invention, the inorganic semiconductor material is preferably a metal oxide as a main component.
Metal oxides are preferable because of their relatively high transparency and excellent electron transport ability.

In the light emitting device of the present invention, it is preferable that the inorganic semiconductor material is composed mainly of titanium oxide.
Titanium oxide is particularly preferable because of its high transparency and excellent electron transport ability.
In the light emitting device of the present invention, the inorganic semiconductor material is preferably in an amorphous state.
By using an amorphous inorganic semiconductor material, trap levels are more reliably formed in the electron transport layer, and the electron transport efficiency in the electron transport layer is further improved.

In the light emitting device of the present invention, the hole transport layer preferably has a region containing a positively charged substance on at least the light emitting layer side.
By having such a region containing a positively charged substance (hereinafter referred to as “first region”), electrons are unevenly distributed near the surface of the electron transport layer due to the electrical action of the substance. To come. For this reason, in the electron transport layer, electrons easily move near the surface. That is, a transport path through which electrons are transported efficiently is formed. As a result, the electron transport efficiency in the electron transport layer is further improved, and the light emission efficiency of the light emitting element can be further improved.

In the light emitting device of the present invention, the region is preferably in a liquid or gel form.
Thereby, the contact area of a 1st area | region (hole transport layer) and a light emitting layer can be increased more. As a result, the light emission efficiency of the light emitting element can be further improved.
In the light emitting device of the present invention, it is preferable that the positively charged substance is mainly composed of amine ions.
The first region is preferably composed of an electrolyte composition as a main material, and an amine ion is used as a positively charged substance, that is, I ₂ and a quaternary ammonium compound iodine salt are used as an electrolyte. By using this combination, an electrolyte composition containing such an electrolyte can have high stability and conductivity, and can be made non-volatile.

In the light emitting device of the present invention, the hole transport layer preferably has a second region mainly composed of a polymer material on the anode side.
Thereby, it can prevent that a 1st area | region contacts a positive electrode directly, and can inject | pour a hole into a 1st area | region efficiently. By providing the second region, the light emission efficiency of the light emitting element can be further improved.

In the light emitting device of the present invention, it is preferable that the second region is in contact with the anode.
Thereby, it is possible to reliably prevent the light emitting element from being enlarged (in particular, thicker) and the efficiency of hole injection into the first region from being lowered.
In the light emitting element of the present invention, the second region is preferably in contact with the region (first region).
Thereby, it is possible to reliably prevent the light emitting element from being enlarged (in particular, thicker) and the efficiency of hole injection into the first region from being lowered.

The light emitting device according to claim 14, wherein the polymer material contains a polythiophene compound.
Thereby, the injection efficiency of holes into the first region can be further improved. As a result, the hole transport efficiency in the whole hole transport layer is further improved.
In the light emitting device of the present invention, the hole transport layer preferably has an average thickness of 0.1 to 100 μm.
Thereby, sufficient light emission efficiency can be obtained while preventing the light emitting element from becoming large (in particular, thick).

The light emitting device of the present invention preferably has a characteristic that the resistance value becomes 100 Ω / cm ² or more when a voltage of 0.5 V is applied so that the cathode is positive and the anode is negative.
Such characteristics indicate that a short circuit (leakage) between the cathode and the anode is suitably prevented or suppressed in the light-emitting element, and the light-emitting element having such characteristics has particularly high luminous efficiency. It will be expensive.
The light-emitting device of the present invention includes the light-emitting element of the present invention.
Thereby, a highly reliable light-emitting device can be obtained.
An electronic apparatus according to the present invention includes the light emitting device according to the present invention.
As a result, a highly reliable electronic device can be obtained.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the light-emitting element, the light-emitting device, and the electronic apparatus of the invention will be described with reference to the accompanying drawings.
1 is a diagram schematically showing a longitudinal section of an embodiment of a light emitting device of the present invention, FIG. 2 is an enlarged view showing the vicinity of each interface (each layer) in the light emitting device shown in FIG. 1, and FIG. FIG. 2 is an enlarged view showing the vicinity of an interface of an electron transport layer, a light emitting layer, and a hole transport layer in the light emitting device shown in FIG. In the following description, for convenience of explanation, the upper side in FIGS.

A light-emitting element (electroluminescence element) 1 shown in FIG. 1 includes a cathode 3, an anode 6, and an electron transport layer 4, a light-emitting layer L, and a hole transport layer 5 interposed between the cathode 3 and the anode 6. Further, a barrier layer 8 is provided between the electron transport layer 4 and the cathode 3. The entire light emitting element 1 is provided on the substrate 2 and is sealed with a sealing member 7.
In this light-emitting element 1, by passing current through the cathode 3 and the anode 6, electrons transported through the electron transport layer 4 and holes transported through the hole transport layer 5 in the light-emitting layer L Are recombined, and excitons (excitons) are generated by the energy released during the recombination, and energy (fluorescence or phosphorescence) is released when the excitons return to the ground state. That is, the light emitting element 1 (light emitting layer L) emits light.

In the present invention, the cathode 3 is composed of a transparent conductive oxide as a main material, and the electron transport layer 4 is composed of an inorganic semiconductor material as a main material.
Thereby, electrons can be efficiently injected (supplied) from the cathode 3 to the electron transport layer 4, and the light emitting device 1 having high light emission efficiency can be obtained, and light emission of the light emitting layer L is seen from the cathode 3 side ( Visual recognition).
Further, since the inorganic semiconductor material is chemically stable, the light-emitting element 1 having excellent durability (lifetime) can be obtained by configuring the electron transport layer 4 with the inorganic semiconductor material as a main material.

Hereinafter, the configuration of each unit will be sequentially described.
The substrate 2 serves as a support for the light emitting element 1. Since the light-emitting element 1 of the present invention is configured to extract light from the cathode 3 side (bottom emission type), the substrate 2 is substantially transparent (colorless transparent, colored transparent, or translucent).
Examples of the constituent material of the substrate 2 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate, quartz glass, and soda glass. Such glass materials can be used, and one or more of these can be used in combination.
Although the average thickness of such a board | substrate 2 is not specifically limited, It is preferable that it is about 0.1-30 mm, and it is more preferable that it is about 0.1-10 mm.

The cathode 3 is an electrode for injecting electrons into the electron transport layer 4 and is mainly composed of a transparent conductive oxide.
Examples of the transparent conductive oxide include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), FTO (Fluorine-containing ITO), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO. 1 type or 2 types or more of these can be used in combination.

On the other hand, the anode 6 is an electrode that injects holes into the hole transport layer 5.
The constituent material of the anode 6 includes, for example, Au, Pt, Ag, Cu or an alloy containing these in addition to the above-described transparent conductive oxide, and one or more of these are combined. Can be used.
Although the average thickness of such a cathode 3 and the anode 6 is not specifically limited, It is preferable that it is about 10-200 nm, respectively, and it is more preferable that it is about 50-150 nm.
Further, the surface resistance of the cathode 3 and the anode 6 is preferably as low as possible. Specifically, it is preferably 100Ω / □ or less, more preferably 50Ω / □ or less. The lower limit value of the surface resistance is not particularly limited, but is usually preferably about 0.1Ω / □.

The electron transport layer 4 has a function of transporting electrons injected from the cathode 3 to the light emitting layer L.
The electron transport layer 4 may be dense, but is preferably porous as shown in FIGS.
As a result, more trap levels are formed in the electron transport layer 4, and electrons are more efficiently transported through the trap levels.

Further, it is possible to increase the formation region of the light emitting layer L described later, that is, to increase the amount (adsorption amount) of the light emitting material to the electron transport layer 4. Further, the hole transport layer 5 described later can also be formed so as to enter the holes of the electron transport layer 4. As a result, the contact area between the light emitting layer L, the electron transport layer 4 and the hole transport layer 5 can be increased, and the recombination sites of holes and electrons are expanded.
For this reason, the light emission efficiency of the light emitting element 1 is improved.

Further, since the light emitting sites are widened, the light emitting material (number of molecules) contributing to light emission is increased, and the rate (degree) at which each light emitting material is altered or deteriorated can be reduced. That is, the durability (life) of the light emitting element 1 can be improved.
The electron transport layer 4 preferably has as high a porosity as possible within a range in which the mechanical strength (film strength) does not decrease remarkably, and specifically, it is preferably about 20 to 75%. More preferably, it is about 60%. Thereby, while preventing the mechanical strength of the electron transport layer 4 from being lowered, more light emitting material can be attached to the electron transport layer 4, and the hole transport layer 5 can be attached to the electron transport layer 4. It is possible to penetrate deeper into the interior.
The electron transport layer 4 is mainly composed of an n-type inorganic semiconductor material.

Examples of the inorganic semiconductor material include titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), zinc oxide (ZnO), aluminum oxide (Al ₂ O ₃ ), tin oxide (SnO ₂ ), ScVO ₄ , YVO ₄ , _{LaVO 4, NdVO 4, EuVO 4} , GdVO 4, ScNbO 4, ScTaO 4, YNbO 4, YTaO 4, ScPO 4, ScAsO 4, ScSbO 4, ScBiO 4, YPO 4, YSbO 4, BVO 4, AlVO 4, GaVO 4 , InVO ₄ , TlVO ₄ , InNbO ₄ , InTaO ₄ , metal oxides such as ZnS and CdS, metal selenides such as CdSe, metals or semiconductor carbides such as TiC and SiC, BN, semiconductor nitrides and the like, such as B 4 _N, these It can be used in combination of at least Chino one or.

Among these, as the inorganic semiconductor material, a metal oxide, particularly, a material mainly composed of titanium oxide is preferable. Metal oxides (particularly titanium oxide) are preferable because of their high transparency and excellent electron transport ability.
The inorganic semiconductor material may be in a single crystal state or a polycrystalline state, but is preferably in an amorphous state. By using an amorphous inorganic semiconductor material, trap levels are more reliably formed in the electron transport layer 4, and the electron transport efficiency in the electron transport layer 4 is further improved.

Although the average thickness of such an electron carrying layer 4 is not specifically limited, It is preferable that it is about 1-50 micrometers, and it is more preferable that it is about 5-30 micrometers. Thereby, it is possible to reduce the thickness of the light emitting element 1 while preventing the mechanical strength (film strength) of the electron transport layer 4 from being lowered. In addition, it is possible to prevent or suppress the absorption of light by the electron transport layer 4 and to efficiently extract light from the light emitting layer L to the cathode 3 side.
In the electron transport layer 4, as shown in FIG. 3, a light emitting layer (light emitting portion) L is formed along the outer surface and the inner surface of the hole.
As a constituent material (light emitting material) of the light emitting layer L, various polymer light emitting materials and various low molecular light emitting materials can be used alone or in combination of two or more kinds.

  Examples of the polymer light-emitting material include polyacetylene compounds such as trans-type polyacetylene, cis-type polyacetylene, poly (di-phenylacetylene) (PDPA), poly (alkyl, phenylacetylene) (PAPA), and poly (para-para-). Fenvinylene) (PPV), poly (2,5-dialkoxy-para-phenylenevinylene) (RO-PPV), cyano-substituted-poly (para-phenvinylene) (CN-PPV), poly (2-dimethyloctyl) Polyparaphenylene vinylene compounds such as silyl-para-phenylene vinylene (DMOS-PPV), poly (2-methoxy, 5- (2′-ethylhexoxy) -para-phenylene vinylene) (MEH-PPV), poly ( 3-alkylthiophene) (PAT), poly (oxypropylene) Polythiophene compounds such as riol (POPT), poly (9,9-dialkylfluorene) (PDAF), poly (dioctylfluorene-alt-benzothiadiazole) (F8BT), α, ω-bis [N, N′-di (Methylphenyl) aminophenyl] -poly [9,9-bis (2-ethylhexyl) fluorene-2,7-zyl] (PF2 / 6am4), poly (9,9-dioctyl-2,7-divinylenefluore Polyfluorene compounds such as nyl-ortho-co (anthracene-9,10-diyl), poly (para-phenylene) (PPP), poly (1,5-dialkoxy-para-phenylene) (RO-PPP) A polyparaphenylene compound such as poly (N-vinylcarbazole) (PVK), Li (methylphenyl silane) (PMPS), poly (naphthyl phenylsilane) (PnPs), polysilane-based compounds such as poly (biphenylyl phenyl silane) (pBPS), and the like.

On the other hand, as a low-molecular light-emitting material, for example, iridium complex in which 2,2′-bipyridine-4,4′-dicarboxylic acid is tricoordinated, factory (2-phenylpyridine) iridium (Ir (ppy) ₃ ) , 8-hydroxyquinoline aluminum (Alq ₃ ), tris (4-methyl-8 quinolinolate) aluminum (III) (Almq ₃ ), 8-hydroxyquinoline zinc (Znq ₂ ), (1,10-phenanthroline) -tris- ( 4,4,4-trifluoro-1- (2-thienyl) -butane-1,3-dionate) europium (III) (Eu (TTA) ₃ (phen)), 2,3,7,8,12, Various metal complexes such as 13,17,18-octaethyl-21H, 23H-porphine platinum (II), distyrylbenzene (DSB), di Benzene compounds such as minodistyrylbenzene (DADSB), naphthalene compounds such as naphthalene and nile red, phenanthrene compounds such as phenanthrene, chrysene, chrysene compounds such as 6-nitrochrysene, perylene, N, Perylene compounds such as N'-bis (2,5-di-t-butylphenyl) -3,4,9,10-perylene-di-carboximide (BPPC), coronene compounds such as coronene, anthracene , Anthracene compounds such as bisstyrylanthracene, pyrene compounds such as pyrene, and 4- (di-cyanomethylene) -2-methyl-6- (para-dimethylaminostyryl) -4H-pyran (DCM) Pyran compounds, acridine compounds such as acridine, stilbene Such stilbene compounds, thiophene compounds such as 2,5-dibenzoxazole thiophene, benzoxazole compounds such as benzoxazole, benzimidazole compounds such as benzimidazole, 2,2 ′-(para-phenylenedivinylene ) -Benzothiazole compounds such as bisbenzothiazole, bistyryl (1,4-diphenyl-1,3-butadiene), butadiene compounds such as tetraphenylbutadiene, naphthalimide compounds such as naphthalimide, Coumarin compounds, perinone compounds such as perinone, oxadiazole compounds such as oxadiazole, aldazine compounds, 1,2,3,4,5-pentaphenyl-1,3-cyclopentadiene ( Like PPCP) Clopentadiene compounds, quinacridone compounds such as quinacridone and quinacridone red, pyridine compounds such as pyrrolopyridine and thiadiazolopyridine, 2,2 ′, 7,7′-tetraphenyl-9,9′-spirobi Examples include spiro compounds such as fluorene, metal or metal-free phthalocyanine compounds such as phthalocyanine (H ₂ Pc) and copper phthalocyanine, and fluorene compounds such as fluorene.

Among these, as a constituent material of the light emitting layer L, a material having a metal complex as a main component is preferable. A light-emitting material containing a metal complex as a main component is preferable because it is relatively easy to attach to an inorganic semiconductor material in a large amount and has excellent light-emitting characteristics.
The amount of the light emitting material attached to the electron transport layer 4 is not particularly limited, but is preferably about 1 × 10 ⁻⁹ to 1 × 10 ⁻⁶ mol per 1 cm ² of the electron transport layer 4. It is more preferable that the amount be about ^10-8 to ^1x10-7 mol. By attaching such an amount of the light emitting material to the electron transport layer 4, the light emission efficiency of the light emitting element 1 can be further improved.

Note that the light emitting material may not form a layer and may adhere (adsorb) to the outer surface of the electron transport layer 4 and the inner surface of the holes in the form of scattered dots. In the case of such a configuration, the whole of the electron transport layer 4 and the light emitting material can be called a light emitting layer.
Between the light emitting layer L and the anode 6, a hole transport layer 5 is provided in contact with the light emitting layer L.

The hole transport layer 5 has a function of transporting holes injected from the anode 6 to the light emitting layer L.
The hole transport layer 5 of the present embodiment is composed of a first region 51 on the light emitting layer L (electron transport layer 4) side and a second region 52 on the anode 6 side.
The first region 51 preferably contains a positively charged substance. Thus, electrons are unevenly distributed near the surface of the electron transport layer 4 due to the electrical action of the substance. For this reason, in the electron transport layer 4, electrons are likely to move near the surface. That is, a transport path through which electrons are transported efficiently is formed. As a result, the electron transport efficiency in the electron transport layer 4 is further improved, and the light emission efficiency of the light-emitting element 1 can be further improved.

The first region 51 may be solid, but is preferably liquid or gel. Accordingly, the first region 51 can be filled deeper into the electron transport layer 4, and the contact area between the first region 51 (hole transport layer 5) and the light emitting layer L can be further increased. be able to. As a result, the light emission efficiency of the light emitting element 1 can be further improved.
Such first region 51 is preferably composed of an electrolyte composition as a main material. Since the electrolyte composition is excellent in hole transport capability, the light emission efficiency of the light-emitting element 1 can be improved by constituting a part of the hole transport layer 5 using the electrolyte composition as a main material.

The electrolyte used in this electrolyte composition is not particularly limited, but for example, halogen systems such as I / I ₃ system, Br / Br ₃ system, Cl / Cl ₃ system, F / F ₃ system, quinone / hydroquinone system Etc., and these can be used alone or as a mixed system.
Among these, I / I ₃ system is preferable as the electrolyte. This electrolyte is one in which an oxidation-reduction reaction is efficiently performed, and the first region 51 containing such an electrolyte is particularly excellent in hole transport ability.

Specific examples of the I / I ₃ system electrolyte include, for example, I ₂ and metal iodides such as LiI, NaI, KI, CsI, and CaI ₂ , tetraalkylammonium iodide, pyridinium iodide, and imidazolium iodide. A combination with a quaternary ammonium compound iodine salt such as id may be mentioned.
In this case, metal ions such as Li ⁺ , Na ⁺ , K ⁺ , Sc ³⁺ , and Ca ²⁺ and amine ions such as tetraalkylammonium ions, pyridinium ions, and imidozolium ions are positively charged as described above. It will function as a substance.
Among these, it is preferable to use an amine ion as a positively charged substance, that is, to use a combination of I ₂ and a quaternary ammonium compound iodine salt as an electrolyte. An electrolyte composition containing such an electrolyte is preferable because it has high stability and conductivity and is non-volatile.

  Examples of the solvent used in the electrolyte composition include various waters, nitriles such as acetonitrile, propionitrile, and benzonitrile, carbonates such as ethylene carbonate and propylene carbonate, polyethylene glycol, polypropylene glycol, and glycerin. Polyhydric alcohols, propylene carbonate and the like, and these can be used alone or as a mixed solvent. By using these solvents, an electrolyte composition having excellent ion conductivity can be obtained.

The concentration of the entire electrolyte in the electrolyte composition is not particularly limited, but is preferably about 0.1 to 25 wt%, and more preferably about 0.5 to 15 wt%.
In addition, basic compounds such as t-butylpyridine, 2-picoline, and 2,6-lutidine may be added to the electrolyte composition so that they function as the positively charged substances described above. .

Furthermore, in the electrolyte composition, I: a method of adding a polymer, II: a method of adding an oil gelling agent, III: a method of adding a polymer precursor and polymerizing it, and IV: adding a polymer In addition, the electrolyte composition can be gelled by a method for causing a crosslinking reaction or the like.
In the case of I, examples of the polymer include thermoplastic resins such as polyethylene oxide (PEO), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), and polymethyl methacrylate (PMMA). Species or a combination of two or more can be used.
Among these, a polymer having at least one of polyacrylonitrile and polyvinylidene fluoride as a main component is particularly preferable.

In the case of II, a compound having an amide structure is preferably used as the oil gelling agent.
In the case of III, examples of the polymer precursor include precursors of various curable resins such as a thermosetting resin, a photocurable resin, and an anaerobic curable resin.
In the case of IV, it is preferable to use a polymer containing a reactive group and a crosslinking agent that undergoes a crosslinking reaction with the reactive group.

Examples of the reactive group include an amino group, a pyridine ring, an imidazole ring, a thiazole ring, an oxazole ring, a triazole ring, a morpholine ring, a piperidine ring, and a piperazine ring.
Examples of the crosslinking agent include halogenated alkyls, halogenated aralkyls, sulfonic acid esters, acid anhydrides, acid chlorides, isocyanate compounds, α, β-unsaturated sulfonyl compounds, α, β-unsaturated carbonyl compounds. , Α, β-unsaturated nitrile compounds and the like.

The second region 52 is a solid layer (or film) and has a function of preventing the first region 51 from directly contacting the anode 6. By providing the second region 52, the interface resistance between the hole transport layer 5 and the anode 6 can be reduced, and holes can be efficiently injected into the first region 51. As a result, the light emission efficiency of the light emitting element 1 can be further improved.
As the constituent material of the second region 52, various p-type polymer materials and various p-type low molecular materials can be used alone or in combination.

Examples of the p-type polymer material (organic polymer) include polyarylamines, fluorene-arylamine copolymers, fluorene-bithiophene copolymers, poly (N-vinylcarbazole), polyvinylpyrene, polyvinylanthracene, polythiophene, Examples thereof include polyalkylthiophene, polyhexylthiophene, poly (p-phenylene vinylene), polytinylene vinylene, pyrene formaldehyde resin, ethylcarbazole formaldehyde resin, and derivatives thereof.
Moreover, the said compound can also be used as a mixture with another compound. As an example, the polythiophene-containing mixture includes poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS).

On the other hand, examples of p-type low molecular weight materials include 1,1-bis (4-di-para-triaminophenyl) cyclohexane and 1,1′-bis (4-di-para-tolylaminophenyl). Arylcycloalkane compounds such as -4-phenyl-cyclohexane, 4,4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetraphenyl-1,1′-biphenyl-4 , 4′-diamine, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-biphenyl-4,4′-diamine (TPD1), N, N′-diphenyl- N, N′-bis (4-methoxyphenyl) -1,1′-biphenyl-4,4′-diamine (TPD2), N, N, N ′, N′-tetrakis (4-methoxyphenyl) -1, 1′-biphenyl-4,4′-diamine (TPD3), , N′-di (1-naphthyl) -N, N′-diphenyl-1,1′-biphenyl-4,4′-diamine (α-NPD), arylamine compounds such as TPTE, N, N, N ′, N′-tetraphenyl-para-phenylenediamine, N, N, N ′, N′-tetra (para-tolyl) -para-phenylenediamine, N, N, N ′, N′-tetra (meta-) Phenylenediamine compounds such as (tolyl) -meta-phenylenediamine (PDA), carbazole compounds such as carbazole, N-isopropylcarbazole, N-phenylcarbazole, stilbene, and 4-di-para-tolylaminostilbene stilbene compounds, oxazole-based compounds such as _{O x} Z, triphenylmethane, triphenylmethane compounds such as m-MTDATA, 1- Pyrazoline compounds such as enyl-3- (para-dimethylaminophenyl) pyrazoline, benzine (cyclohexadiene) compounds, triazole compounds such as triazole, imidazole compounds such as imidazole, 1,3,4-oxa Diazole, oxadiazole compounds such as 2,5-di (4-dimethylaminophenyl) -1,3,4, -oxadiazole, anthracene, anthracene such as 9- (4-diethylaminostyryl) anthracene Compound, fluorenone, 2,4,7, -trinitro-9-fluorenone, 2,7-bis (2-hydroxy-3- (2-chlorophenylcarbamoyl) -1-naphthylazo) fluorenone such as fluorenone, polyaniline Aniline compounds like silane Compounds, pyrrole compounds such as 1,4-dithioketo-3,6-diphenyl-pyrrolo- (3,4-c) pyrrolopyrrole, fluorene compounds such as fluorene, porphyrins, porphyrins such as metal tetraphenylporphyrin Compounds, quinacridone compounds such as quinacridone, phthalocyanine, copper phthalocyanine, tetra (t-butyl) copper phthalocyanine, metal or metal-free phthalocyanine compounds such as iron phthalocyanine, copper naphthalocyanine, vanadyl naphthalocyanine, monochlorogallium Metallic or metal-free naphthalocyanine compounds such as phthalocyanine, N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine, N, N, N ′, N′-tetraphenylbenzidine Benzidine like Compounds, and the like.

Among these, as a constituent material of the second region 52, a material mainly composed of a polymer material is preferable. By configuring the second region 52 using a polymer material as a main material, the function of preventing the contact of the first region 51 with the anode 6 and the efficiency of injection of holes into the first region 51 are improved. It can be made more excellent by the function to do.
In particular, as a constituent material of the second region 52, a material containing a polythiophene compound, in particular, the aforementioned PEDOT / PSS is suitable. Thereby, the injection efficiency of holes into the first region 51 can be further improved.

If the second region 52 is provided between the first region 51 and the anode 6, the above-described effect is sufficiently exhibited, but the second region 52 is in contact with at least one of the first region 51 and the anode 6. It is preferable that it is in contact with both. Thereby, it is possible to reliably prevent the light emitting element 1 from being enlarged (in particular, thicker) and the efficiency of hole injection into the first region 51 from being lowered.
The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 0.1 to 100 μm, and more preferably about 1 to 30 μm. Thereby, sufficient light emission efficiency can be obtained while preventing the light-emitting element 1 from becoming large (in particular, thick).

In addition, any one of the 1st area | region 51 and the 2nd area | region 52 can be abbreviate | omitted as needed.
When the first region 51 is omitted, that is, when the entire hole transport layer 5 is solid, in addition to the p-type organic semiconductor material as described above, for example, a metal iodide compound such as CuI or AgI In addition, a p-type inorganic semiconductor material such as a metal halide compound such as a metal bromide compound such as AgBr, or a metal thiocyanate (metallodanide compound) such as CuSCN can be used.

When the hole transport layer 5 is mainly composed of an organic polymer (polymeric organic semiconductor material), a cationic group such as an amino group, pyridyl group, imidazolyl group or the like is introduced into a part of the polymer. The thing itself can function as a positively charged substance.
Further, the hole transport layer 5 itself can be omitted as necessary. In this case, a barrier layer 8 described later can also be omitted.

The sealing member 7 is provided so as to cover the cathode 3, the electron transport layer 4 on which the light emitting layer L is formed, the hole transport layer 5, and the anode 6. The sealing member 7 is hermetically sealed to block oxygen and moisture. It has the function to do. By providing the sealing member 7, effects such as improvement in reliability of the light emitting element 1 and prevention of deterioration / deterioration (improvement in durability) can be obtained.
Examples of the constituent material of the sealing member 7 include Al, Au, Cr, Nb, Ta, Ti, alloys containing these, silicon oxide, various resin materials, and the like. In addition, when using the material which has electroconductivity as a constituent material of the sealing member 7, in order to prevent a short circuit, the electron transport layer 4 in which the sealing member 7, the cathode 3, the light emitting layer L were formed, and a hole An insulating film is preferably provided between the transport layer 5 and the anode 6 as necessary.

Further, the sealing member 7 may be formed in a flat plate shape so as to face the substrate 2 and be sealed with a sealing material such as a thermosetting resin.
In such a light emitting device 1, the hole transport layer 5 (first region 51) is prevented from contacting the cathode 3 via the electron transport layer 4 between the electron transport layer 4 and the cathode 3. A barrier layer (underlayer) 8 having a function of suppressing is provided.

By providing the barrier layer 8, it is possible to prevent the light emitting element 1 from being short-circuited over time and reducing the light emission efficiency, that is, to improve durability (lifetime).
The barrier layer (short-circuit prevention means) 8 can be configured arbitrarily if it can prevent the hole transport layer 5 from coming into contact with the cathode 3. However, as shown in FIG. It is preferably formed so as to be smaller than the porosity of the electron transport layer 4. By setting it as such a structure, it can prevent or suppress more reliably that the positive hole transport layer 5 contacts the cathode 3. FIG. Further, the barrier layer 8 having such a configuration can be formed relatively easily.

When the porosity of the barrier layer 8 is A [%] and the porosity of the electron transport layer 4 is B [%], B / A is preferably 1.1 or more, and preferably 5 or more. More preferably, it is 10 or more. Thereby, the barrier layer 8 can more reliably prevent or suppress contact between the hole transport layer 5 and the cathode 3.
Specifically, the porosity A of the barrier layer 8 is preferably 20% or less, more preferably 5% or less, and even more preferably 2% or less. That is, the barrier layer 8 is preferably a dense layer. Thereby, the effect can be further improved.

The thickness ratio between the barrier layer 8 and the electron transport layer 4 is not particularly limited, but is preferably about 1:99 to 60:40, and more preferably about 10:90 to 40:60. preferable. In other words, the ratio of the thickness occupied by the barrier layer 8 in the whole of the barrier layer 8 and the electron transport layer 4 is preferably about 1 to 60%, and more preferably about 10 to 40%. Thereby, the barrier layer 8 can more reliably prevent or suppress contact between the hole transport layer 5 and the cathode 3.
Specifically, the average thickness of the barrier layer 8 is preferably 3 μm or less, and more preferably 0.1 to 1 μm. Thereby, the effect can be further improved. Further, it is possible to prevent or suppress the light absorption by the barrier layer 8 and to prevent the light emission luminance of the light emitting element 1 from being lowered.

The constituent material of the barrier layer 8 is not particularly limited. For example, in addition to the various semiconductor materials mentioned in the electron transport layer 4, various inorganic insulator materials such as SiO ₂ and various organic insulator materials are used. However, among these, it is preferable to have the same electrical conductivity as the electron transport layer 4, and it is more preferable to use a material having the same composition as the material constituting the electron transport layer 4. Thereby, the transfer of electrons between the barrier layer 8 and the electron transport layer 4 is performed smoothly.

The resistance values in the thickness direction of the barrier layer 8 and the electron transport layer 4 are not particularly limited, but the resistance values in the thickness direction of the barrier layer 8 and the electron transport layer 4 as a whole, that is, the barrier layer 8 The resistance value in the thickness direction of the stack of the electron transport layer 4 and the electron transport layer 4 is preferably 100 Ω / cm ² or more, and more preferably 1 kΩ / cm ² or more. Thereby, the leak (short circuit) between the positive hole transport layer 5 and the cathode 3 can be prevented or suppressed more reliably, and the durability (life) of the light emitting element 1 can be further improved.

In addition, the interface between the barrier layer 8 and the electron transport layer 4 may not be clear or clear, but is not clear (unclear), that is, the barrier layer 8 and the electron transport layer 4 Are preferably partially overlapping each other.
Furthermore, it is preferable that the barrier layer 8 and the electron transport layer 4 are integrated as shown in FIG. 2, that is, the barrier layer 8 and the electron transport layer 4 are integrally formed. Thereby, the transfer of electrons between the barrier layer 8 and the electron transport layer 4 can be performed more reliably (efficiently).

Further, if the barrier layer 8 is provided between the cathode 3 and the electron transport layer 4, the above effect is sufficiently exhibited, but is in contact with at least one of the cathode 3 and the electron transport layer 4. It is preferable that it is in contact with both. Thereby, it is possible to prevent the light emitting element 1 from being enlarged (in particular, thicker) and the efficiency of electron injection into the light emitting layer L from being lowered.
The installation position of the barrier layer 8 is not limited to that shown in the figure, and may be provided, for example, between the electron transport layer 4 and the light emitting layer L.

It is also possible to provide a dense portion and a rough portion in the thickness direction of the electron transport layer 4 so that the dense portion functions as the barrier layer 8.
In this case, an arbitrary number of dense portions can be provided at arbitrary positions in the thickness direction of the electron transport layer 4. Specifically, the electron transport layer 4 has a configuration in which one dense portion is provided on the cathode 3 side, a configuration in which one dense portion is provided on the light emitting layer L side, and a portion in which a rough portion is sandwiched between dense portions. It can also be set as the structure which has a part which has the part which has a dense part with a rough part, etc.

Such a light-emitting element 1 has such a characteristic that when a voltage of 0.5 V is applied so that the cathode 3 is positive and the anode 6 is negative, the resistance value is 100 Ω / cm ² or more. Preferably, it has a characteristic of 1 kΩ / cm ² or more. Such characteristics indicate that in the light-emitting element 1, a short circuit (leakage) between the cathode 3 and the anode 6 is preferably prevented or suppressed, and the light-emitting element 1 having such characteristics is The luminous efficiency is particularly high.
Such a light emitting element 1 can be manufactured as follows, for example.

[1] First, the substrate 2 is prepared, and the cathode 3 is formed on the substrate 2.
The cathode 3 is formed by, for example, chemical vapor deposition (CVD) such as plasma CVD, thermal CVD or laser CVD, dry plating such as vacuum deposition, sputtering or ion plating, vapor deposition such as thermal spraying, electrolysis It can be formed using a wet plating method such as plating, immersion plating, electroless plating, a liquid phase film forming method such as a sol-gel method or a MOD method, or a metal foil bonding.

[2] Next, the barrier layer 8 is formed on the cathode 3.
The barrier layer 8 is formed by, for example, a sol-gel method, a vapor deposition (vacuum vapor deposition) method, a sputtering method (high frequency sputtering, DC sputtering), a spray pyrolysis method, a jet mold (plasma spraying) method, a CVD method, or the like. Among these, the sol-gel method is preferable.

  This sol-gel method is very easy to operate. In addition, by using a sol-gel method, a barrier layer forming material for forming the barrier layer 8 is, for example, a dipping method, dripping, doctor blade method, spin coating method, brush coating, spray coating method, roll coating. The barrier layer 8 having a desired film thickness can be formed relatively easily without requiring a large-scale apparatus.

In particular, it is preferable to use a metal organic deposition (or decomposition) method (hereinafter abbreviated as “MOD method”), which is a kind of sol-gel method, for forming the barrier layer 8.
According to this MOD method, the reaction of the precursor of the constituent material of the barrier layer 8 (for example, hydrolysis, polycondensation, etc.) is prevented in the barrier layer forming material. (With good reproducibility). Further, the obtained barrier layer 8 can be dense (with a porosity within the above range).
When the barrier layer 8 is composed of titanium dioxide as a main material, as a precursor thereof, for example, an organic titanium compound such as titanium tetraisopropoxide (TPT), titanium tetramethoxide, titanium tetraethoxide, titanium tetrabutoxide, or the like is used. Can be used.

[3] Next, the electron transport layer 4 is formed on the barrier layer 8.
The electron transport layer 4 is formed, for example, by supplying an electron transport layer forming material containing particles of the inorganic semiconductor material as described above onto the barrier layer 8 and baking it after the dedispersion medium. be able to.
The particles of the inorganic semiconductor material can be produced, for example, by using a method such as a sol / gel method, a gas phase method, or a liquid phase method, and it is particularly preferable to use the sol / gel method. According to the sol-gel method, an amorphous inorganic semiconductor material can be obtained relatively easily.

In the case of using the sol-gel method, the dispersion liquid when the particles of the inorganic semiconductor material are produced may be used as it is as the material for forming the electron transport layer.
The material for forming an electron transport layer may be prepared by dispersing the previously produced particles in a dispersion medium. In this case, a sol liquid used in the step [2] or the sol-gel method in the production of particles can also be used as the dispersion liquid.
As a method for supplying the electron transport layer forming material, various coating methods as described above can be used.

[4] Next, the light emitting layer L is formed so as to be in contact with the electron transport layer 4.
The light emitting layer L can be formed, for example, by bringing a liquid containing a light emitting material into contact with the electron transport layer 4 and then removing the solvent (or dedispersing medium).
As a result, the light emitting material is adsorbed, bonded or the like on the outer surface of the electron transport layer 4 and the inner surface of the pores, and the light emitting layer L is formed along these surfaces.

As a method of bringing the liquid containing the luminescent material into contact with the electron transport layer 4, for example, a method of immersing the laminate of the substrate 2, the cathode 3, the barrier layer 8, and the electron transport layer 4 in the liquid containing the luminescent material (immersion) Method), a method of applying a liquid containing a light emitting material to the electron transport layer 4 (coating method), a method of supplying a liquid containing a light emitting material to the electron transport layer 4 in a shower form, and the like.
Examples of the solvent (or dispersion medium) for preparing the liquid containing the light emitting material include various water, methanol, ethanol, isopropyl alcohol, acetonitrile, ethyl acetate, ether, methylene chloride, NMP (N-methyl-2-pyrrolidone), and the like. These can be used, and one or more of these can be used in combination.

Examples of the solvent removal method include a method in which the solvent is left under atmospheric pressure or reduced pressure, and a method in which a gas such as air or nitrogen gas is blown.
In addition, you may heat-process with respect to the said laminated body at the temperature of about 60-100 degreeC for about 0.5 to 2 hours as needed. Thereby, the luminescent material can be more firmly adsorbed (bonded) to the electron transport layer 4.

[5] On the other hand, the anode 6 is formed on the inner upper surface of the sealing member 7.
The anode 6 can be formed using, for example, a vacuum deposition method, a sputtering method, a metal foil bonding, or the like.
[6] Next, the second region 52 is formed on the lower surface of the anode 6.
The second region 52 can be formed in the same manner as the light emitting layer L.

[7] Next, the sealing member 7 is covered so as to cover the electron transport layer 4 on which the cathode 3 and the light emitting layer L are formed, and is bonded to the substrate 2.
[8] Next, from the injection port (not shown) provided in the sealing member 7, the electrolyte composition is transferred between the electron transport layer 4 in which the light emitting layer L is formed and the second region 52. Inject into the space.
Next, the inlet is sealed with a sealing material such as an adhesive.
The light emitting element 1 of the present invention is manufactured through the above steps.

Such a light emitting element 1 can be used as, for example, a light source. Further, a display device (the light emitting device of the present invention) can be configured by arranging a plurality of light emitting elements 1 in a matrix.
The driving method of the display device is not particularly limited, and may be either an active matrix method or a passive matrix method.

Next, an example of a display device to which the light emitting device of the present invention is applied will be described.
FIG. 4 is a longitudinal sectional view showing an embodiment of a display device to which the light emitting device of the present invention is applied.
The display device 10 shown in FIG. 4 includes a base body 20 and a plurality of light emitting elements 1 provided on the base body 20.

The base body 20 includes a substrate 21 and a circuit unit 22 formed on the substrate 21.
The circuit unit 22 includes a protective layer 23 made of, for example, a silicon oxide layer formed on the substrate 21, a driving TFT (switching element) 24 formed on the protective layer 23, a first interlayer insulating layer 25, And a second interlayer insulating layer 26.
The driving TFT 24 includes a semiconductor layer 241 made of silicon, a gate insulating layer 242 formed on the semiconductor layer 241, a gate electrode 243 formed on the gate insulating layer 242, a source electrode 244, and a drain electrode 245. have.
On such a circuit portion 22, the light emitting element 1 is provided corresponding to each driving TFT 24. Adjacent light emitting elements 1 are partitioned by a first partition wall portion 31 and a second partition wall portion 32.

In the present embodiment, the cathode 3 of each light emitting element 1 constitutes a pixel electrode and is electrically connected to the drain electrode 245 of each driving TFT 24 by the wiring 27. The anode 6 of each light emitting element 1 is a common electrode.
Then, a sealing member (not shown) is bonded to the base 20 so as to cover each light emitting element 1, and each light emitting element 1 is sealed.
The display device 10 may be monochromatic display, and color display is also possible by selecting a light emitting material used for each light emitting element 1.
Such a display device 10 (the light emitting device of the present invention) can be incorporated into various electronic devices.

FIG. 5 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.
In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.
In the personal computer 1100, the display unit included in the display unit 1106 is configured by the display device 10 described above.

FIG. 6 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the present invention is applied.
In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206, and a display unit.
In the mobile phone 1200, the display unit is configured by the display device 10 described above.

FIG. 7 is a perspective view showing the configuration of a digital still camera to which the electronic apparatus of the present invention is applied. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

A display unit is provided on the back of a case (body) 1302 in the digital still camera 1300, and is configured to display based on an imaging signal from the CCD, and functions as a finder that displays an object as an electronic image.
In the digital still camera 1300, the display unit is configured by the display device 10 described above.

A circuit board 1308 is installed inside the case. The circuit board 1308 is provided with a memory that can store (store) an imaging signal.
A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side of the case 1302 (on the back side in the illustrated configuration).
When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory of the circuit board 1308.

  In the digital still camera 1300, a video signal output terminal 1312 and an input / output terminal 1314 for data communication are provided on the side surface of the case 1302. As shown in the figure, a television monitor 1430 is connected to the video signal output terminal 1312 and a personal computer 1440 is connected to the data communication input / output terminal 1314 as necessary. Further, the imaging signal stored in the memory of the circuit board 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.

In addition to the personal computer (mobile personal computer) of FIG. 5, the mobile phone of FIG. 6, and the digital still camera of FIG. 7, the electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, Monitor direct-view video tape recorder, laptop personal computer, car navigation system, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and automatic ticket vending machines for financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiographs, ultrasound diagnostic devices, internal Endoscope display device), fish finder, various measuring instruments, Vessels such (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.
As mentioned above, although the light emitting element of this invention, the light-emitting device, and the electronic device were demonstrated based on embodiment of illustration, this invention is not limited to these.

Next, specific examples of the present invention will be described.
1. Production of light emitting device (Example 1)
[1] First, two transparent glass substrates having an average thickness of 0.5 mm were prepared.
[2] Next, ITO was deposited on one glass substrate by a sputtering method to form a cathode having an average thickness of 100 nm.
The surface resistance of the cathode was about 40Ω / □.

[3] Next, titanium oxide (TiO ₂ ) was deposited on the cathode by a vacuum vapor deposition method to form a barrier layer having an average thickness of 0.5 μm.
The barrier layer had a porosity of 2%.
[4] Next, an electron transport layer having an average thickness of 10 μm was formed on the barrier layer.
First, TiO ₂ particles (average particle size: 10 nm) synthesized by a sol-gel method were prepared.

Note that TiO ₂ was confirmed to be in an amorphous state in these particles by analysis by X-ray diffraction.
Next, an aqueous ethanol solution containing the TiO ₂ (inorganic semiconductor material) particles and polyethylene glycol was prepared.
Then, this ethanol aqueous solution was applied onto the barrier layer by a spin coating method (2000 rpm) and then dried.

Next, the aggregate of TiO ₂ particles was baked at 450 ° C. for 30 minutes. Thereby, an electron transport layer was obtained.
The electron transport layer had a porosity of 55%.
Further, when the resistance value in the thickness direction of the laminate of the barrier layer and the electron transport layer was measured, it was 1 kΩ / cm ² or more.

[5] Next, a luminescent material-containing liquid containing iridium complex (luminescent material) in which 2,2′-bipyridine-4,4′-dicarboxylic acid is tricoordinated and cholic acid is used for the substrate after firing ( (40 ° C.) for 8 hours, and then sequentially washed with ethanol and acetonitrile.
The amount of iridium complex deposited per 1 cm ² of the electron transport layer was set to 1 × 10 ⁻⁸ mol.

[6] Moreover, ITO was deposited on the other glass substrate by a sputtering method to form an anode having an average thickness of 100 nm.
The surface resistance of the ITO electrode was about 40Ω / □.
[7] Next, an aqueous dispersion containing PEDOT / PSS (hole transport material) was applied onto the anode by a spin coating method (2000 rpm) and then dried.
As a result, a second region of the hole transport layer having an average thickness of 20 μm was formed.

[8] Next, two glass substrates were opposed to each other, and the periphery thereof was sealed with an epoxy resin. In addition, it sealed so that the injection hole which inject | pours electrolyte composition may remain at this time.
In addition, the average thickness of the space to be formed was set to 40 μm.
[9] First, I ₂ and LiI as an electrolyte were dissolved in ethylene glycol to prepare a liquid electrolyte composition. The electrolyte concentration was 10 wt%.
Next, after the electrolyte composition was injected from the injection port, the injection port was sealed with an epoxy resin adhesive.
Thus, the first region of the hole transport layer was formed to complete the light emitting element.

(Example 2)
A light emitting device was manufactured in the same manner as in Example 1 except that the step [9] was changed as follows.
First, in the same manner as in Example 1, a liquid electrolyte composition was prepared.
Next, this electrolyte composition and molten polyethylene oxide were mixed at a weight ratio of 5: 1 to obtain a mixture.
Next, this mixture was injected from the injection port and then allowed to stand at room temperature to gel the electrolyte composition.

(Example 3)
A light emitting device was manufactured in the same manner as in Example 1 except that the step [9] was changed as follows.
First, in the same manner as in Example 1, a liquid electrolyte composition was prepared.
Next, the electrolyte composition and the polyimide resin precursor were mixed at a weight ratio of 5: 1 to obtain a mixture.
As the polyimide resin precursor, pyromellitic anhydride and paraphenylenediamine were used at a molar ratio of 1: 1.
Next, the mixture was injected from the injection port, and then heated to 120 ° C. to gel the electrolyte composition.

Example 4
A light emitting device was manufactured in the same manner as in Example 1 except that I ₂ and imidazolium iodide were used as the electrolyte.
In the light emitting device manufactured in each example, the resistance value was measured by applying a voltage of 0.5 V with the cathode being positive and the anode being negative. / Cm ² or more.

2. Evaluation Each light emitting device manufactured in each example was evaluated for light emission efficiency and durability (life).
The luminous efficiency was evaluated by applying a voltage from 0 V to 6 V with a DC power source, measuring the current value, and measuring the luminance with a luminance meter. Further, durability (life) was evaluated by performing constant current driving with an initial luminance of 400 cd / m ² .
As a result, in each of the light emitting devices of each example, light emission could be confirmed from the cathode side.
Moreover, in the light emitting element of each Example, high luminous efficiency and excellent durability were confirmed, and in particular, the light emitting element of Example 4 was more prominent.

It is a figure which shows typically the longitudinal cross-section of embodiment of the light emitting element of this invention. It is a figure which expands and shows the interface vicinity of each part (each layer) in the light emitting element shown in FIG. It is a figure which expands further and shows the interface vicinity of the electron carrying layer in the light emitting element shown in FIG. 1, a light emitting layer, and a hole transport layer further. It is a longitudinal cross-sectional view which shows embodiment of the display apparatus to which the light-emitting device of this invention is applied. 1 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which an electronic apparatus of the present invention is applied. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) to which the electronic device of this invention is applied. It is a perspective view which shows the structure of the digital still camera to which the electronic device of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light emitting element 2 ... Substrate 3 ... Cathode 4 ... Electron transport layer L ... Light emitting layer 5 ... Hole transport layer 51 ... 1st area | region 52 ... 2nd area | region 6 ... Anode 7 ... Sealing member 8 ... Barrier layer 10 ... Display device 20 ... Substrate 21 ... Substrate 22 ... Circuit part 23 ... Protection layer 24 ... Driving TFT 241 ... Semiconductor layer 242 ... Gate insulating layer 243 …… Gate electrode 244 …… Source electrode 245 …… Drain electrode 25 …… First interlayer insulating layer 26 …… Second interlayer insulating layer 27 …… Wiring 31 …… First partition wall portion 32 …… Second partition wall portion 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation buttons 1204 ... Earpiece 1206 ... Mouthpiece 1300 Digital still camera 1302 Case (body) 1304 Light receiving unit 1306 Shutter button 1308 Circuit board 1312 Video signal output terminal 1314 Input / output terminal for data communication 1430 Television monitor 1440 Personal computer

Claims (15)

A cathode mainly composed of a transparent conductive oxide, an anode, an electron transport layer, a light emitting layer, and a hole transport layer are interposed from the cathode side between the cathode and the anode, and further, an electron transport layer A light emitting element in which the light emitting layer emits light by energizing the cathode and the anode by providing a barrier layer between the cathode and the anode,
The electron transport layer is porous and mainly composed of an inorganic semiconductor material,
The barrier layer is provided in contact with the electron transport layer, and the porosity thereof is smaller than the porosity of the electron transport layer, and is made of a material having the same composition as the material constituting the electron transport layer. ,
A light emitting element configured to view the light emission from the cathode side. The barrier layer, the light emitting device according to 請 Motomeko 1 that have a preventing or inhibiting function the hole transport layer from contacting with the cathode via the electron transport layer. The light emitting device according to claim 2 , wherein the hole transport layer has a region containing a positively charged substance on at least the light emitting layer side. The light emitting device according to claim 3 , wherein the region is in a liquid or gel form. The light-emitting element according to claim 3 , wherein the positively charged substance is mainly composed of amine-based ions. The light emitting device according to claim 2, wherein the hole transport layer has a second region mainly composed of a polymer material on the anode side. The light emitting device according to claim 6 , wherein the polymer material contains a polythiophene compound. The light emitting device according to claim 2 , wherein the hole transport layer has an average thickness of 0.1 to 100 μm. The light emitting device according to claim 1, wherein the electron transport layer has a porosity of 20 to 75%. The light emitting device according to claim 1, wherein the electron transport layer has an average thickness of 1 to 50 μm. The light-emitting element according to claim 1, wherein the inorganic semiconductor material contains a metal oxide as a main component. The light emitting device according to claim 1, wherein the inorganic semiconductor material is mainly composed of titanium oxide. The light emitting device according to claim 1, wherein the inorganic semiconductor material is in an amorphous state. A light-emitting device comprising the light-emitting element according to claim 1 . An electronic apparatus comprising the light emitting device according to claim 14 .

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