JP4742623B2 - Method for manufacturing light emitting device - Google Patents

Description

The present invention relates to the production how the light-emitting element.

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 light emitting color elements, high luminance and high efficiency elements have been developed, and there are various practical applications such as use of the light emitting element as a pixel 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 manufacturing how the light-emitting element which can be easily produced a light-emitting device having excellent luminous efficiency and durability (life).

Such an object is achieved by the present invention described below.
The method for producing a light emitting device of the present invention includes a step of forming an electron transport layer on one surface side of the cathode,
Forming a light emitting layer in contact with the electron transport layer;
A step of forming an anode on the side opposite to the electron transport layer of the light emitting layer,
The step of forming the electron transport layer includes a first step of depositing a tubular or granular inorganic semiconductor material to form an aggregate of the inorganic semiconductor materials in a layered manner,
Against the aggregate, by performing a process of contacting the solvent capable of dissolving the inorganic semiconductor material, and a second step of bonding by the contact interface between the inorganic semiconductor material melt of the inorganic semiconductor material Have
In the second step, a treatment for unevenly distributing a part of the melt on the cathode side of the aggregate is performed .
Thereby, the light emitting element which is excellent in luminous efficiency and durability (lifetime) can be obtained easily.

In the method for manufacturing a light emitting device of the present invention, the treatment for unevenly distributing a part of the lysate to the cathode side of the aggregate is a treatment by any of movement, centrifugation, and pressurization due to the weight of the lysate. it is preferable that.
In the method for manufacturing a light emitting device of the present invention, the solvent is preferably an acid or an alkali solution.
Thereby, the light emitting element excellent in the mechanical strength of an electron carrying layer can be obtained easily by melt | dissolving an inorganic semiconductor material and producing | generating a melt.

In the method for manufacturing a light-emitting element according to the present invention, the melt is preferably a salt of the inorganic semiconductor material .
In the method for manufacturing a light-emitting element according to the present invention, it is preferable that after the second step, a third step of performing a process of changing the dissolved matter into an oxide is provided.
As a result, the dissolved matter becomes chemically more stable, so that a light-emitting element that is superior in mechanical strength of the electron transport layer can be easily obtained.

In the method for manufacturing a light emitting element of the present invention, the treatment is preferably performed by heating in an oxidizing atmosphere .
Thereby, a melt can be made into an oxide easily and cheaply .

In the method for manufacturing a light emitting device of the present invention, it is preferable that at least a portion on the anode side of the electron transport layer is porous.
Thereby, the formation area of the light emitting layer can be increased, that is, the adhesion amount (adsorption amount) of the light emitting material to the electron transport layer can be increased. Further, the hole transport layer can also be formed so as to enter the holes of the electron transport layer.
For this reason, the contact area between the light emitting layer and the electron transport layer and hole transport layer can be increased. As a result, a recombination site between holes and electrons spreads, and a light-emitting element with high emission efficiency can be obtained.
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, a light-emitting element having excellent durability (lifetime) can be obtained.

The light emitting device of the present invention preferably includes a hole transport layer and a barrier layer having a function of preventing or suppressing the hole transport layer from contacting the cathode via the electron transport layer.
Thereby, in a light emitting element, it can prevent that a short circuit arises with time and a light emission efficiency falls, ie, the improvement of durability (life) can be aimed at.
In the light emitting device of the present invention, the barrier layer is preferably formed so that the porosity thereof is smaller than the porosity of the electron transport layer.
Thereby, 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, 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, it is preferable to have a hole transport layer between the light emitting layer and the cathode.
Thereby, luminous efficiency can be improved more.

In the light emitting device of the present invention, it is preferable that at least a region on the light emitting layer side (hereinafter referred to as “first region”) of the hole transport layer is mainly composed of an electrolyte composition.
Thereby, luminous efficiency can be further improved.
In the light emitting device of the present invention, the electrolyte composition is preferably in a liquid or gel form.
Thereby, the contact area of a positive 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, the electrolyte composition is preferably an I / I ₃ system as an electrolyte.
In this electrolyte, an oxidation-reduction reaction is efficiently performed, and the first region containing such an electrolyte is particularly excellent in hole transport ability.
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, it is preferable that the second region is in contact with a region configured using the electrolyte composition as a main material.
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 device of the present invention, the polymer material preferably 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.

In the manufacturing method of the light emitting element of this invention, it is preferable that the said inorganic semiconductor material is a thing which has a metal oxide as a main component.
Metal oxides are preferred because they are particularly excellent in electron transport ability.
In the manufacturing method of the light emitting element of this invention, it is preferable that the said inorganic semiconductor material is a thing which has a titanium oxide as a main component.
Titanium oxide is particularly stable chemically, can be easily obtained in a tube shape, and has particularly excellent electron transport ability.

Hereinafter, preferred embodiments of a method for manufacturing a light-emitting element, a light-emitting element, a light-emitting device, and an electronic apparatus according to the present 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 an electron transport layer 4, a light-emitting layer (light-emitting part) L, and a hole transport layer 5 between a cathode 3, an anode 6, and 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.

The substrate 2 serves as a support for the light emitting element 1. Since the light emitting element 1 of the present embodiment has a configuration for extracting light from the side opposite to the substrate 2 (top emission type), the substrate 2 and the cathode 3 are not particularly required to be transparent.
Examples of the substrate 2 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate, and quartz glass and soda glass. Transparent substrate composed of glass material, substrate composed of ceramic material such as alumina, metal substrate such as stainless steel with oxide film (insulating film) formed on it, composed of opaque resin material An opaque substrate such as a patterned substrate can be used.

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.
When the light emitting element 1 is configured to extract light from the substrate 2 side (bottom emission type), the substrate 2 and the cathode 3 are each substantially transparent (colorless transparent, colored transparent, translucent).

The cathode 3 is an electrode that injects electrons into an electron transport layer 4 described later. As a constituent material of the cathode 3, a material having a small work function is preferably used.
Examples of the constituent material of the cathode 3 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. These can be used alone or in combination of two or more thereof (for example, a multi-layer laminate).

In particular, when an alloy is used as the constituent material of the cathode 3, it is preferable to use an alloy containing a stable metal element such as Ag, Al, or Cu, specifically an alloy such as MgAg, AlLi, or CuLi. By using such an alloy as the constituent material of the cathode 3, the electron injection efficiency and stability of the cathode 3 can be improved.
Although the average thickness of such a cathode 3 is not specifically limited, It is preferable that it is about 100-10000 nm, and it is more preferable that it is about 200-500 nm.

The surface resistance of the cathode 3 is preferably as low as possible. Specifically, it is preferably 50Ω / □ or less, and more preferably 20Ω / □ or less. The lower limit value of the surface resistance is not particularly limited, but is usually preferably about 0.1Ω / □.
On the other hand, the anode 6 is an electrode for injecting holes into the hole transport layer 5 described later. As a constituent material of the anode 6, it is preferable to use a material having a large work function and excellent conductivity.

Examples of the constituent material of the anode 6 include ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , oxides such as Al-containing ZnO, Au, Pt, and Ag. Cu, alloys containing these, and the like can be used, and one or more of these can be used in combination.
The average thickness of the anode 6 is not particularly limited, but is preferably about 10 to 200 nm, and more preferably about 50 to 150 nm.

Further, the surface resistance of the anode 6 is preferably as low as possible. Specifically, it is preferably 100Ω / □ or less, and 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. In addition, the cathode 3 has a function of preventing a hole transport layer 5 described later from contacting the cathode 3, that is, a function similar to the barrier layer 8 described later.

The electron transport layer 4 may be dense, but is preferably porous as shown in FIGS.
Thereby, the formation area of the light emitting layer L mentioned later can be increased, ie, the adhesion amount (adsorption amount) of the light emitting material to the electron transport layer 4 can be increased. Further, the hole transport layer 5 described later can also be formed so as to enter the holes of the electron transport layer 4.
For this reason, the contact area between the light emitting layer L, the electron transport layer 4 and the hole transport layer 5 can be increased. As a result, the recombination sites of holes and electrons are expanded, and 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 composed of an inorganic semiconductor material as a main material. Since the inorganic semiconductor material is chemically stable, the durability of the light-emitting element 1 can be further improved by configuring the electron transport layer 4 with the inorganic semiconductor material as a main material.
As shown in FIG. 3, such an electron transport layer 4 includes a tube-shaped inorganic semiconductor material 41 (hereinafter simply referred to as “tube 41”) and / or a granular inorganic semiconductor material 42 (hereinafter simply referred to as “particle”). 42 ”)) as a main material. A light emitting material as will be described later is bonded (adsorbed) to the outer peripheral surface and inner peripheral surface of the tube 41 and the surface of the particles 42.

The tube 41 has a high electron mobility in the longitudinal direction. Therefore, when the electron transport layer 4 contains the tube 41, the electron transport capability of the entire electron transport layer 4 can be further improved.
Further, since the tube 41 has a large specific surface area, it is possible to increase the bonding amount of the light emitting material to the surface of the tube 41, and to sufficiently provide a contact area between the light emitting material and the hole transport layer 5 described later. Can be secured. As a result, the light emission efficiency of the light emitting element 1 can be further improved.

Here, the tube 41 contained in the electron transport layer 4 preferably has an outer diameter of about 3 to 70 nm, and more preferably about 5 to 50 nm. When the outer diameter of the tube 41 is within the above range, the mechanical strength of the tube 41 is increased, and stable electron transport can be performed.
Moreover, it is preferable that the length of the tube 41 is about 5-300 nm, and it is more preferable that it is about 10-200 nm. When the length of the tube 41 is shorter than the lower limit value, the electron transport ability may be lowered. Moreover, when the length of the tube 41 is longer than the said upper limit, the gap | interval between tubes 41 tends to become large, and there exists a possibility that the coupling | bonding amount of the tube 41 and a luminescent material may fall.

The specific surface area of the tube 41 is preferably in the range of about 50~2000m ² / g, and more preferably about 100~1500m ² / g. When the specific surface area of the tube 41 is within the above range, the amount of coupling between the tube 41 and the light emitting material becomes larger.
The tube 41 has a substantially cylindrical shape whose outer diameter is substantially constant, a substantially conical shape (horn shape) whose outer diameter gradually increases or decreases toward one end, and is in the middle of the longitudinal direction. It may be a Y-shaped branch that branches off at the top, or a concentric overlap of these.

Further, since the electron transport layer 4 contains the particles 42, the gaps between the tubes 41 can be filled, and charge (electron) hopping (jumping) between the tubes 41 can be promoted. For this reason, the electron transport capability as the whole electron transport layer 4 can further be improved.
The average particle diameter of the particles 42 is preferably about 10 to 150 nm, and more preferably about 20 to 100 nm. When the average particle diameter of the particles 42 is within the above range, the gap between the tubes 41 can be more effectively filled, and the electron transport ability of the entire electron transport layer 4 can be further improved.

In the electron transport layer 4, the ratio of the tube 41 and the particles 42 is preferably about 95: 5 to 60:40, more preferably about 90:10 to 70:30, by weight. Thereby, the said effect in the electron carrying layer 4 can be made more remarkable.
The tube 41 and the particles 42 and the contact interfaces between the tubes 41 and the particles 42 (hereinafter simply referred to as “contact interfaces”) are, for example, the inorganic semiconductor material constituting the tubes 41 and the particles 42. The melted material, the oxide of the melted material, and the inorganic semiconductor material are once melted or softened, and then joined by solidified solidified material or the like.
By this bonding, the strength at the contact interface is improved, and the mechanical strength of the electron transport layer 4 as a whole can be improved. In addition, there is an advantage that electrons move easily at the contact interface.

Examples of the inorganic semiconductor material constituting the tube 41 and the particles 42 include titanium oxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), zinc oxide (ZnO), aluminum oxide (Al ₂ O ₃ ), and 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, metal oxides such as InTaO _4, ZnS, metal sulfides such as CdS, metal selenide such as CdSe, TiC, metal or semiconductor carbide such as SiC, BN, B Semiconductor nitrides and the like, such as N, may be used singly or in combination of two or more of them.

Among these, as the inorganic semiconductor material, a material containing a metal oxide as a main component is preferable. Metal oxides are preferred because they are particularly excellent in electron transport ability.
Further, among the metal oxides, as the inorganic semiconductor material, a material mainly composed of titanium oxide (TiO ₂ ) is more preferable. Titanium oxide is particularly stable chemically, can be easily obtained in a tube shape, and has particularly excellent electron transport ability.

Hereinafter, the manufacturing method of the tube 41 which uses titanium oxide as a main material is demonstrated as a representative.
First, titanium oxide is synthesized.
For the synthesis of titanium oxide, for example, a sol-gel method, a gas phase method, a liquid phase method, or the like can be used.
For example, in the sol-gel method, first, a solution in which a titanium alkoxide such as titanium isopropoxide that is a precursor of titanium oxide is mixed with a solvent is prepared, and an acid is added to this solution.

As the solvent, a solvent which does not contain at least water, for example, alcohol (for example, methanol, ethanol, propanol, butanol, etc.) is preferably used.
Moreover, as an acid, nitric acid, hydrochloric acid, an acetic acid etc. can be used, for example.
Subsequently, by adding water to this solution, while hydrolyzing a precursor, a solvent and water are removed and a gelled material is obtained. And the titanium oxide is obtained by baking this gelled material at high temperature.

Here, when the precursor is hydrolyzed, the solution is preferably heated. Thereby, the crystallinity of the obtained titanium oxide can be improved, the growth of particles can be promoted, and the electron mobility of the obtained tube 41 can be improved.
The vapor phase method is a method of obtaining titanium oxide by baking hydrous titanium oxide at a high temperature.

First, an ore containing titanium such as ilmenite ore is reacted with a strong acid such as nitric acid or sulfuric acid to obtain a solution containing a salt such as titanium nitrate or titanium sulfate.
Next, the salt in the solution is hydrolyzed to precipitate insoluble hydrous titanium oxide, and the solvent in the solution is removed to obtain hydrous titanium oxide. And titanium oxide is obtained by baking this hydrous titanium oxide at high temperature.
The firing temperature in this firing is usually preferably about 800 to 900 ° C.
The liquid phase method is a method of obtaining titanium oxide by heating titanium tetrachloride together with oxygen and hydrogen. As a result, titanium tetrachloride changes to titanium alone and is oxidized to titanium oxide.

Next, the tube 41 is obtained from the obtained titanium oxide.
First, titanium oxide is added to an alkaline solution and an alkali treatment is performed.
Examples of the alkaline solution include aqueous solutions of hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, aqueous solutions of hydroxides of alkaline earth metals such as magnesium hydroxide and calcium hydroxide, and aqueous ammonia solutions.
In the alkali treatment, it is preferable to involve heating, and the heating conditions are usually a heating temperature of about 60 to 150 ° C. and a heating time of about 10 to 20 hours.

Next, hydrochloric acid and pure water are added to the alkaline solution to which titanium oxide is added, and neutralization is performed so that the hydrogen ion concentration (pH) of the solution is about 6.5 to 7.5.
Next, the tube 41 can be obtained by removing the solvent in the solution and kneading the precipitate for about 1 to 10 hours.
The kneading method is not particularly limited, and examples thereof include kneading using a mortar.

In this embodiment, the manufacturing method of the tube 41 mainly composed of titanium oxide has been described as a representative. However, the tube 41 mainly composed of another inorganic semiconductor material is also manufactured using a manufacturing method similar to that of titanium oxide. can do.
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 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.
In the light emitting layer L, electrons transported through the electron transport layer 4 recombine with holes transported through the hole transport layer 5 described later, and exciton is generated by the energy released upon the recombination. (Exciton) is generated, and energy (fluorescence or phosphorescence) is released when the exciton returns to the ground state. That is, the light emitting layer L emits light.
As the constituent material (light emitting material) of such a 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 such a 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. More preferably, it is about 1 × 10 ⁻⁹ to 1 × 10 ⁻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.
The hole transport layer 5 is provided in contact with such a 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 is configured using 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 composition may be in a solid state, but is preferably in a liquid or gel form. Thereby, the electrolyte composition can be filled deeper into the electron transport layer 4, and the contact area between the hole transport layer 5 and the light emitting layer L can be further increased. As a result, the light emission efficiency of the light emitting element 1 can be further improved.
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.
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%.
Moreover, it is preferable to add a basic compound such as t-butylpyridine, 2-picoline, or 2,6-lutidine to the electrolyte composition.
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.
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 about 0.1 to 1 μm. Thereby, the effect can be further improved.
As the constituent material of the barrier layer 8 is not particularly limited, for example, other various inorganic semiconductor materials mentioned in the electron transport layer 4, various organic semiconductor materials, various inorganic insulating materials such as SiO _2, various organic insulating A body material or the like can be used, but among these, it is preferable that the material has an electrical conductivity equivalent to that of the electron transport layer 4, and in particular, a material having the same composition as the inorganic semiconductor material constituting the electron transport layer 4 Is more preferable. 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 may be 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 oxide 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.
Hereinafter, each process will be described sequentially.
[3-1] First, a dispersion containing the tube 41 and the particles 42 is prepared.
Examples of the dispersion medium used for preparing the dispersion include water, methanol, ethanol, n- or i-propanol, monohydric alcohols such as n-, s- or t-butanol, ethylene glycol, and trimethylene glycol. Glycols (polyhydric alcohols), ketones such as acetone, methyl ethyl ketone, diethyl ketone, acetylacetone and isophorone, esters such as methyl acetate, ethyl acetate and butyl acetate, ether alcohols such as methoxyethanol and ethoxyethanol , Ethers such as dioxane and tetrahydrofuran, acid amides, aromatic hydrocarbons and the like, and one or more of them can be used in combination.

Among these, it is preferable to use water, alcohols, glycols or the like as the dispersion medium. By using these liquids, the tube 41 and the particles 42 can be satisfactorily dispersed in the dispersion liquid, and the dispersion liquid can be easily and reliably supplied onto the barrier layer 8.
The content of the tube 41 and the particles 42 in the dispersion is preferably about 5 to 90 wt%, and more preferably about 10 to 30 wt%. If the contents of the tube 41 and the particles 42 are too small, it may take more time and effort than necessary to form the electron transport layer 4 having the desired thickness. On the other hand, if the content of the tube 41 and the particle 42 is too large, the dispersibility of the tube 41 and the particle 42 in the dispersion liquid is lowered, and it may be difficult to prepare the dispersion liquid and supply it onto the barrier layer 8. is there.
In addition, a dispersant that improves the dispersibility of the tube 41 and the particles 42 in the dispersion medium is added to the dispersion as necessary.

  Although it does not specifically limit as a dispersing agent, For example, volatile dispersing agents, such as nonionic organic type dispersing agents, such as polyvinyl alcohol, carboxymethylcellulose, and polyethylene glycol, Tristearic acid metal salt (for example, aluminum salt etc.) , Metal distearate (eg, aluminum salt, barium salt, etc.), stearic acid metal salt (eg, calcium salt, lead salt, zinc salt, etc.), linolenic acid metal salt (eg, cobalt salt, manganese salt, lead salt, Zinc salts, etc.), octanoic acid metal salts (eg, aluminum salts, calcium salts, cobalt salts, etc.), oleic acid metal salts (eg, calcium salts, cobalt salts, etc.), palmitic acid metal salts (eg, zinc salts, etc.), Naphthenic acid metal salts (for example, calcium salts, cobalt salts, manganese salts, lead salts, zinc salts, etc.), resins Metal salts (for example, calcium salts, cobalt salts, manganese lead salts, zinc salts), polyacrylic acid metal salts (for example, sodium salts), polymethacrylic acid metal salts (for example, sodium salts), polymaleic acid metal salts Anionic organic dispersants such as (for example, sodium salts), acrylic acid-maleic acid copolymer metal salts (for example, sodium salts), polystyrenesulfonic acid metal salts (for example, sodium salts), 4 Nonionic dispersants such as cationic organic dispersants such as quaternary ammonium salts and inorganic dispersants such as tricalcium phosphate can be used. Moreover, these dispersing agents can also be used 1 type or in combination of 2 or more types.

Among these, a volatile dispersant is particularly preferable as the dispersant. This is because the volatile dispersant does not remain after the formation of the electron transport layer 4 (after completion), and therefore, there is little possibility of adversely affecting the characteristics of the electron transport layer 4.
When the dispersion contains a dispersant, the content of the dispersant in the dispersion is not particularly limited, but is preferably 1.0 wt% or less, and about 0.01 to 0.5 wt%. More preferred.

In preparing the dispersion, it is preferable to uniformly disperse the tube 41 and the particles 42 in the dispersion. Thereby, in the obtained electron carrying layer 4, the tube 41 and the particle | grains 42 can be distributed (existing) more uniformly. As a result, variations in characteristics such as electron mobility in each part of the electron transport layer 4 can be more reliably suppressed.
Examples of a method for uniformly dispersing the tube 41 and the particles 42 include a method of sufficiently stirring the dispersion and a method of applying ultrasonic waves to the dispersion.

[3-2] Next, as shown in FIG. 4 (a), the prepared dispersion is supplied onto the barrier layer 8 to form the liquid coating 43, and then at least the dispersion medium in the liquid coating 43. By removing a part, the aggregate 44 of the tube 41 and the particles 42 is formed in layers as shown in FIG. 4B (first step).
The method for supplying the dispersion is not particularly limited. For example, dip coating, spin coating, slit coating, cap coating, dispenser, spray coating, roll coating, screen printing, ink jet printing, etc. It is preferable to use these various coating methods. According to the coating method, the liquid coating 43 can be easily and reliably formed on the barrier layer 8.
Examples of the method for removing the dispersion medium include methods such as heating, leaving in an atmospheric pressure or reduced pressure atmosphere, and injecting an inert gas (for example, nitrogen gas), and one of these methods. Alternatively, two or more kinds can be used in combination. Among these, the method by heating is particularly preferable. Thereby, a dispersion medium can be removed easily and uniformly.

[3-3] Next, as shown in FIG. 4C, the contact interface is joined by applying a predetermined treatment to the aggregate 44 (second step).
Here, the predetermined treatment includes a method of dissolving a part of the tube 41 and the particles 42 and a method of melting or softening the vicinity of the contact interface between the tube 41 and the particles 42.
Each of these cases will be described below.

[3-3A] When Dissolving Tube 41 and Particle 42 First, a solvent capable of dissolving the tube 41 and the particle 42 (inorganic semiconductor material) is brought into contact with the aggregate 44. As a result, the surfaces of the tube 41 and the particles 42 are dissolved, and a dissolved product is generated.
Although it does not specifically limit as a solvent, It is preferable to use an acid or an alkali solution. By using such a solution, the inorganic semiconductor material constituting the tube 41 and the particles 42 can be easily changed to ions or the like and dissolved (eluted) in the solvent.

Specifically, as the acid solution, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, boric acid, borohydrofluoric acid, acetic acid, Examples include a solution containing one or a combination of two or more organic acids such as citric acid, oxalic acid, trifluoroacetic acid, and p-toluenesulfonic acid.
As the alkaline solution, one or more of inorganic alkalis such as sodium hydroxide, potassium hydroxide, calcium hydroxide and ammonia and organic alkalis such as pyridine, triethylamine and tributylamine are combined. A solution containing a thing is mentioned.

The acid or alkali content in the solvent is slightly different depending on the type of acid or alkali used, but is preferably about 1 to 8 mol / L, more preferably about 3 to 6 mol / L. By setting the acid or alkali content in the above range, the surfaces of the tube 41 and the particles 42 can be reliably dissolved.
Moreover, as a solvent used when preparing a solvent, the thing similar to the dispersion medium used when preparing the dispersion liquid demonstrated by the said process [3-1] can be used.

Among these, it is preferable to use water, alcohols, glycols or the like as the solvent. By using these liquids, the acid or alkali can be dissolved well in the solvent, and the supply to the aggregate 44 can be performed easily and reliably.
The method for bringing the solvent into contact with the aggregate 44 is not particularly limited. For example, the solvent is supplied using the various coating methods described in the above-mentioned step [3-2], and is allowed to penetrate into the aggregate 44 by capillary action. The method can be used.

In addition, when the tube 41 and the particles 42 are melted as the predetermined treatment, it is preferable that a part of the melt is unevenly distributed on the cathode side of the aggregate 44.
Thereby, a melt | dissolution obstruct | occludes the gap | interval in the aggregate | assembly 44, and a new layer is formed. Since this new layer has a lower porosity than the electron transport layer 4, it can function as a barrier layer that prevents the hole transport layer 5 from contacting the cathode 3.

Therefore, the barrier layer 8 described above can be omitted.
Here, examples of the method for causing the lysate to be unevenly distributed on the cathode 3 side include methods such as movement by its own weight, centrifugation, and pressurization.
Further, after the contact interface is joined with the melt, a treatment for changing the melt into an oxide may be performed (third step). Examples of the dissolved material include salts generated by dissolving an inorganic semiconductor material.

Such a dissolved substance becomes chemically more stable by changing to an oxide, and the characteristics of the electron transport layer 4 can be improved.
The method for changing the melt into an oxide is not particularly limited. For example, a method such as heat treatment, light irradiation, laser irradiation, or electromagnetic wave irradiation can be used. Among these, it is preferable to use heat treatment. . By heating, the dissolved product can be converted into an oxide easily and inexpensively.
For example, when the dissolved material is an inorganic salt, after the inorganic salt is decomposed by heating, oxygen atoms in the atmosphere are combined with the inorganic material to generate an inorganic oxide.
Moreover, it is preferable to perform said method to change a melted substance into an oxide under an oxidizing atmosphere. Thereby, a melt can be changed to an oxide more certainly.

The heating temperature is preferably about 50 to 500 ° C, and more preferably about 150 to 350 ° C. If the heating temperature is too low, there is a possibility that the change of the dissolved material to the oxide does not proceed sufficiently. On the other hand, even if the temperature of the heat treatment exceeds the upper limit, no further effect can be expected.
The heating time is preferably about 1 to 50 minutes, and more preferably about 5 to 30 minutes. With the heating time within the above range, the change of the dissolved material to the oxide can be sufficiently advanced.

Moreover, by performing both the said process [3-2] and this process by selecting heat processing, ie, performing both removal of the dispersion medium from the liquid film 43, and oxidation of a dissolved material by heating, These steps can be performed continuously. As a result, there is an advantage that labor and cost can be reduced.
In addition, in the aggregate | assembly which joined the contact interface obtained before this 3rd process, when the target characteristic is acquired, you may make it abbreviate | omit the 3rd process.

[3-3B] When melting or softening the tube 41 and the particle 42 The inorganic semiconductor material constituting the surface of the tube 41 and the particle 42 is melted or softened, and after the inorganic semiconductor material is once melted or softened, the solidified solidified product The contact interface is joined by, for example.
Since the melt or softened material reinforces the bonding at the contact interface in the aggregate 44, the mechanical strength of the entire electron transport layer 4 can be improved.

  As a method for melting or softening this inorganic semiconductor material, for example, heat treatment, hydrothermal treatment, laser irradiation, electromagnetic wave irradiation, electron beam irradiation, ion beam irradiation, arc, plasma, etc. can be used, among these, It is preferably performed by at least one of heat treatment, hydrothermal treatment, laser irradiation, and electromagnetic wave irradiation. According to these treatments, the inorganic semiconductor material can be melted or softened easily and inexpensively.

When performing the heat treatment, the heating temperature is appropriately set according to the melting point of the inorganic semiconductor material and is not particularly limited, but is preferably about 500 to 1000 ° C, more preferably about 600 to 900 ° C. .
The heating time is appropriately set according to the heating temperature, and is not particularly limited, but is preferably about 30 seconds to 30 minutes, and more preferably about 1 minute to 20 minutes.
The heating atmosphere is appropriately set according to the composition of the inorganic semiconductor material, but is preferably an inert atmosphere such as argon.

Hydrothermal treatment is a method of treating the aggregate 44 with high-pressure steam (saturated steam). By using the hydrothermal treatment, the aggregate 44 can be processed at a relatively low temperature (for example, about 100 to 200 ° C.) at which water is evaporated.
The pressure in the hydrothermal treatment is preferably about 0.1 to 10 MPa, and more preferably about 0.2 to 5 MPa.
The heating time is not particularly limited, but is preferably about 5 to 60 minutes, and more preferably about 10 to 50 minutes.

Laser irradiation is a method of irradiating the assembly 44 with laser light and processing it.
Examples of the laser include a ruby laser, a semiconductor laser, a YAG laser, a femtosecond laser, a glass laser, a YVO4 laser, a Ne—He laser, an Ar laser, and a CO ₂ laser. Among these, a YAG laser or a femtosecond laser is preferably used because continuous oscillation can be easily performed at room temperature and controllability in a low irradiation energy region is good.

The laser irradiation conditions vary slightly depending on the composition of the inorganic semiconductor material. For example, in the case of a YAG laser, the energy intensity is about 0.5 to 5 W, and in the case of a femtosecond laser, about 0.05 to 1 W. Is preferred.
The laser beam diameter is preferably about 1 to 100 μm, and more preferably about 2 to 20 μm.

The electromagnetic wave irradiation is a method of irradiating the aggregate 44 with an electromagnetic wave and processing it.
About such irradiation conditions of electromagnetic waves, although slightly different depending on the composition of the inorganic semiconductor material, for example, the frequency of the electromagnetic waves is preferably about 1 to 100 GHz, and more preferably about 2 to 30 GHz. Moreover, the output of electromagnetic waves is preferably about 5 to 50 kW, and the irradiation time is preferably about 3 to 60 minutes.
As described above, the electron transport layer 4 having a porous portion at least on the anode side is obtained.
In addition, the porosity (degree of porosity) of the electron transport layer 4 can be adjusted by selecting each joining method at the time of joining as described above and setting various conditions in the joining method.

[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. 5 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. 5 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. 6 is a perspective view showing the 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. 7 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. 8 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.

The electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, in addition to the personal computer (mobile personal computer) in FIG. 6, the mobile phone in FIG. 7, and the digital still camera in FIG. 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, AlLi was deposited on one glass substrate by a vacuum vapor deposition method to form a cathode having an average thickness of 300 nm.
The surface resistance of the cathode was about 5Ω / □.

[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.
[4-1] First, titanium oxide synthesized by a sol-gel method was kneaded in a mortar to obtain tubular titanium oxide (outer diameter: 5 nm, length: 30 nm, specific surface area: 500 m ² / g).
Next, titanium oxide particles (average particle size: 10 nm) were prepared.
Next, an aqueous ethanol solution containing these tubular and granular titanium oxide and polyethylene glycol was prepared.

[4-2] Next, this aqueous ethanol solution was applied onto the barrier layer by a spin coat method (2000 rpm) to form a liquid film.
Next, this liquid coating was heat-treated at 150 ° C. for 30 minutes to remove the solvent and dispersion medium in the liquid coating. Thereby, aggregates of tubular and granular titanium oxide were obtained. The ratio of tube-shaped titanium oxide to granular titanium oxide was 80:20 by weight.

[4-3] Next, a 3 mol / L hydrogen chloride aqueous solution was applied onto the aggregate by a spin coating method (2000 rpm).
Next, the aggregate coated with the aqueous hydrogen chloride solution was subjected to heat treatment at 250 ° C. for 20 minutes to obtain an electron transport layer.
The electron transport layer had a porosity of 50%.

[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.
In addition, it was made for the adhesion amount per 1 cm < ² > of the electron carrying layer of an iridium complex to be 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, in the step [4-3], a 6 mol / L hydrogen fluoride aqueous solution was used instead of the hydrogen chloride aqueous solution.
The electron transport layer had a porosity of 40%.
(Example 3)
A light emitting device was manufactured in the same manner as in Example 1 except that, in the step [4-3], a 3 mol / L sodium hydroxide aqueous solution was used instead of the hydrogen chloride aqueous solution.
The electron transport layer had a porosity of 35%.

Example 4
A light emitting device was manufactured in the same manner as in Example 1 except that the contact interface was joined by hydrothermal treatment in the step [4-3].
Hydrothermal treatment was performed by exposing the aggregate to high-pressure steam at 150 ° C. for 40 minutes.
The electron transport layer had a porosity of 55%.

(Example 5)
A light emitting device was manufactured in the same manner as in Example 1 except that the contact interface was bonded by microwave irradiation in the step [4-3].
Microwave irradiation was performed by irradiating the aggregate with microwaves having a frequency of 28 GHz and an output of 20 kW for 30 minutes.
The electron transport layer had a porosity of 60%.

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, high luminous efficiency and excellent durability were confirmed.

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 figure (longitudinal sectional view) for demonstrating the manufacturing method of the light emitting element shown in FIG. 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 41 ... Tube 42 ... Particles 43 ... Liquid coating 44 ... Aggregate L ... Light emitting layer 5 ... Hole transport layer 51 …… First region 52 …… Second 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 portion 32 …… Second partition portion 1100 …… Personal computer 1102 …… Keyboard 1104 …… Main body portion 1106 …… Display unit 1200 …… Mobile phone 1202 …… Operation buttons 1204 …… Earpiece 1206 …… Transmission mouth 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 (9)

Forming an electron transport layer on one side of the cathode; and
Forming a light emitting layer in contact with the electron transport layer;
A step of forming an anode on the side opposite to the electron transport layer of the light emitting layer,
The step of forming the electron transport layer includes a first step of depositing a tubular or granular inorganic semiconductor material to form an aggregate of the inorganic semiconductor materials in a layered manner,
Against the aggregate, by performing a process of contacting the solvent capable of dissolving the inorganic semiconductor material, and a second step of bonding by the contact interface between the inorganic semiconductor material melt of the inorganic semiconductor material Have
In the second step, a method of manufacturing a light emitting element, wherein a treatment for unevenly distributing a part of the melt on the cathode side of the aggregate is performed . 2. The light emitting device according to claim 1, wherein the process of unevenly distributing a part of the lysate on the cathode side of the aggregate is a process by any of movement, centrifugation, and pressurization due to the weight of the lysate. Manufacturing method. The solvent, the method of manufacturing the light emitting device according to claim 1 or 2 which is an acid or alkaline solution.   The method for manufacturing a light-emitting element according to claim 1, wherein the dissolved matter is a salt of the inorganic semiconductor material. After the second step, the method of manufacturing the light emitting device according to any one of claims 1 to 4 having a third step of performing processing for changing the lysate oxide. The light emitting device manufacturing method according to claim 5, wherein the treatment is performed by heating in an oxidizing atmosphere . The electron transport layer, the manufacturing method of the light emitting device according to any one of portion of at least the anode side claims 1 to porous 6. The inorganic semiconductor material, manufacturing method of a light-emitting device according to any one of claims 1 to 7 as a main component a metal oxide. The inorganic semiconductor material, manufacturing method of a light-emitting device according to any one of claims 1 to 8 as a main component titanium oxide.

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