JP2013131573A - Ink for deposition, deposition method, manufacturing method of light-emitting element, light-emitting element, light-emitting device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink for deposition capable of being easily wet and spread without using an additive agent such as a surfactant even on a layer formed by using an aqueous solvent or a dispersion medium when using a nonaqueous solvent or a dispersion medium, and to provide a deposition method, a manufacturing method of a light-emitting element, a light-emitting element manufactured by using the manufacturing method, and a light-emitting device and electronic apparatus, equipped with the light-emitting element.SOLUTION: The ink for deposition contains a deposition material and a liquid medium which either dissolves or disperses the deposition material, wherein the liquid medium has surface tension of 35dyn/cmor less and contains an ether compound represented by formula (I) below.

Description

  The present invention relates to a film forming ink, a film forming method, a method for manufacturing a light emitting element, a light emitting element, a light emitting device, and an electronic apparatus.

  An organic electroluminescence element (organic EL element) is a light emitting element having a structure in which at least one light emitting organic layer (light emitting layer) is interposed between an anode and a cathode. In such a light emitting device, by applying an electric field between the cathode and the anode, electrons are injected into the light emitting layer from the cathode side and holes are injected from the anode side, and electrons and holes are injected into the light emitting layer. Recombination generates excitons, and when the excitons return to the ground state, the energy is emitted as light.

In general, in an organic EL element, a hole injection layer is provided on an anode, and a hole transport layer or a light emitting layer is provided on the hole injection layer.
As a method for forming these layers (film forming method), a method using a film forming ink in which a film forming material is dissolved or dispersed is known (for example, see Patent Document 1).
Since such a film forming method can be patterned without using a photolithography method, there is an advantage that the manufacturing process becomes simple and the amount of raw materials used is small.

In general, in such a film formation method, when forming a hole injection layer, an aqueous solvent (dispersibility mixed with water) or a dispersion medium is used, whereas when forming a hole transport layer or a light emitting layer, A non-aqueous solvent (a property that does not mix with water) or a dispersion medium is used.
Therefore, when forming the hole transport layer or the light emitting layer, the constituent material of the hole transport layer or the light emitting layer or its precursor is placed on the hole injection layer formed using an aqueous solvent or dispersion medium. A film-forming ink dissolved or dispersed in a non-aqueous solvent or dispersion medium is applied.

However, a conventional ink for film formation using a non-aqueous solvent or dispersion medium has a large contact angle (that is, low wettability) with respect to a hole injection layer formed using an aqueous solvent or dispersion medium, and is sufficiently There was a problem that it was not possible to spread it.
In Patent Document 1, a surfactant is added to the solvent or dispersion medium in order to avoid such a problem. However, since the surfactant remaining in the obtained film deteriorates the characteristics of the light-emitting element, it is practically used. It was not right.

JP 2008-77958 A

  The object of the present invention is to use a non-aqueous solvent or dispersion medium without using an additive such as a surfactant on the layer formed using the aqueous solvent or dispersion medium. Film-forming ink, film-forming method, and light-emitting element manufacturing method capable of being easily spread by wetting, and light-emitting element manufactured by such a light-emitting element manufacturing method, and a light-emitting device and an electronic device including the light-emitting element To provide equipment.

Such an object is achieved by the present invention described below.
The film-forming ink of the present invention comprises a film-forming material,
A liquid medium for dissolving or dispersing the film-forming material,
The liquid medium has a surface tension of 35 dyn / cm ² or less and contains an ether compound represented by the following formula (I).

［上記式（Ｉ）において、Ｒ_１およびＲ_２は、それぞれ、炭素数１以上４以下の直鎖アルキル基、分岐アルキル基または環状アルキル基である。Ｒ_３は、炭素数１以上３以下のアルキレン基である。また、ｎは、０以上４以下の整数である。また、ｎが２以上である場合、Ｒ_３は互いに同じであっても異なっていてもよい。］

[In the above formula (I), R ₁ and R ₂ are each a linear alkyl group, branched alkyl group or cyclic alkyl group having 1 to 4 carbon atoms. R ₃ is an alkylene group having 1 to 3 carbon atoms. N is an integer of 0 or more and 4 or less. When n is 2 or more, R ₃ may be the same as or different from each other. ]

According to the film-forming ink configured as described above, when a non-aqueous solvent or dispersion medium is used, it can be easily applied to a layer (film) formed using the aqueous solvent or dispersion medium. Can spread and wet.
In addition, since the film-forming ink of the present invention does not require the use of an additive such as a surfactant, the film characteristics can be prevented from deteriorating due to the additive remaining in the obtained film.

  In particular, the ether compound used in the film-forming ink of the present invention has an optimized number of ether oxygen atoms and carbon number and does not contain hetero atoms other than ether oxygen atoms (that is, polar groups other than ether groups). (For example, it does not contain esters, acetates, ketones, hydroxyl groups, carboxyl groups, sulfo groups), so that it can be used as a non-aqueous solvent or dispersion medium, and even if it remains in the resulting film, Adverse effects on the physical characteristics can be reduced. Further, such a compound has a low aggressiveness to the film forming material, and in this respect as well, it is possible to prevent the deterioration of characteristics of the obtained film.

In the film-forming ink of the present invention, in the formula (I), n is preferably 2 or more and 4 or less.
As a result, both the wettability of the film-forming ink on the layer (film) formed using an aqueous solvent or dispersion medium and the desolvation property or dedispersion medium property of the film-forming ink are excellent. It can be. Further, it is possible to prevent the boiling point of the liquid medium (ether compound) from becoming too low, and as a result, it is possible to prevent clogging of a nozzle of a droplet discharge head used in a droplet discharge method, for example.

In the film-forming ink of the present invention, in the formula (I), R ₃ preferably has 2 or 3 carbon atoms.
Accordingly, when the film forming material is soluble in a non-aqueous solvent, the film forming material is surely dissolved in the liquid medium and the liquid medium is not intended (for example, a droplet discharge method) It is possible to prevent or suppress the dissolution of the member constituting the droplet discharge head used in the above.

In the film-forming ink of the present invention, the content of the ether compound in the liquid medium is preferably 0.1% to 100% by weight.
Thereby, the wettability of the film-forming ink on the layer (film) formed using an aqueous solvent or dispersion medium can be improved.
In the film-forming ink of the present invention, the liquid medium preferably contains an aromatic hydrocarbon compound in addition to the ether compound.
As a result, when the film-forming material is soluble in a non-aqueous solvent, the film-forming material is surely dissolved in the liquid medium, and at the time of producing the film-forming ink, an ether-based compound and an aromatic compound are used. Depending on the mixing ratio with the group hydrocarbon compound, a liquid medium having a desired surface tension can be easily prepared.

In the film-forming ink of the present invention, the film-forming material is preferably soluble in a non-aqueous solvent.
Such a film forming material can be dissolved in a liquid medium.
In the film-forming ink of the present invention, the film-forming material is preferably a material constituting a hole transport layer or a light-emitting layer of an organic electroluminescence element or a precursor thereof.
In general, in an organic EL element, a hole injection layer is provided on an anode, and a hole transport layer or a light emitting layer is provided on the hole injection layer. Then, when forming the hole transport layer or the light emitting layer, the constituent material or precursor of the hole transport layer or the light emitting layer is placed on the hole injection layer formed using an aqueous solvent or dispersion medium. A film-forming ink dissolved or dispersed in a non-aqueous solvent or dispersion medium is applied.
Therefore, when the film-forming ink of the present invention is used for forming the hole transport layer or the light emitting layer, the effect of the present invention becomes remarkable.

The film-forming ink of the present invention is preferably used to form a film composed of the film-forming material as a main material by applying it to a substrate and removing the liquid medium.
As a result, a film intended for film formation or a precursor film thereof can be formed.
The film-forming ink of the present invention is preferably used for film formation by a droplet discharge method.
Thereby, the film-forming ink can be applied to a desired position and region even in a fine region. In addition, the droplet discharge method has an advantage that the film forming process is simpler than the vapor phase film forming method, and the amount of raw material (film forming material) used is small.

The film forming method of the present invention comprises a step of applying the film forming ink of the present invention on a substrate,
And removing the liquid medium from the film-forming ink to form a film.
According to such a film forming method, when a non-aqueous solvent or dispersion medium is used, an additive such as a surfactant is also applied to the layer formed using the aqueous solvent or dispersion medium. Without being used, it can be easily wetted and spread. As a result, a film having excellent film quality can be formed easily and in a short time.

The method for producing a light emitting device of the present invention comprises a step of applying the film forming ink of the present invention on a substrate,
And removing the liquid medium from the film-forming ink to form a hole transport layer or a light-emitting layer.
According to such a method for producing a light-emitting element, for example, when forming a hole transport layer or a light-emitting layer with a film-forming ink using a non-aqueous solvent or dispersion medium, an aqueous solvent or dispersion medium is used. The film-forming ink can be easily wetted and spread on the hole injection layer formed in this manner without using an additive such as a surfactant. As a result, a hole transport layer or a light emitting layer having excellent film quality can be formed easily and in a short time. In particular, since the surfactant does not remain in the light emitting element, the characteristics of the light emitting element can be improved.

The light emitting device of the present invention is manufactured using the method for manufacturing a light emitting device of the present invention.
Accordingly, it is possible to provide a light emitting element that is inexpensive and has excellent light emitting characteristics.
The light emitting device of the present invention includes the light emitting element of the present invention.
Accordingly, a light emitting device that is inexpensive and has excellent light emitting characteristics can be provided.
An electronic apparatus according to the present invention includes the light emitting device according to the present invention.
Thereby, an electronic device having excellent reliability can be provided.

It is a figure which shows typically the longitudinal cross-section of the light emitting element of this invention. It is a perspective view which shows schematic structure of a droplet discharge apparatus. FIG. 3 is a schematic diagram illustrating a schematic configuration of a droplet discharge head provided in the droplet discharge device of FIG. 2. It is a longitudinal cross-sectional view which shows embodiment of a display apparatus provided with the light-emitting device of this invention. 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.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a film forming ink, a film forming method, a light emitting element manufacturing method, a light emitting element, a light emitting device, and an electronic apparatus according to the present invention will be described based on preferred embodiments shown in the accompanying drawings.
(Light emitting element)
FIG. 1 is a diagram schematically showing a longitudinal section of a light emitting device of the present invention. In the following description, for convenience of explanation, the upper side in FIG. 1 will be described as “upper” and the lower side as “lower”.

A light-emitting element (electroluminescence element) 1 shown in FIG. 1 emits white light by emitting R (red), G (green), and B (blue).
Such a light emitting device 1 includes a positive hole injection layer 4, a positive hole transport layer 5, a red light emitting layer (first light emitting layer) 6, a first intermediate layer 7A and a blue color between an anode 3 and a cathode 12. The light emitting layer (second light emitting layer) 8, the second intermediate layer 7B, the green light emitting layer (third light emitting layer) 9, the electron transport layer 10, the electron injection layer 11, and the cathode 12 are laminated in this order. Is.

In other words, the light-emitting element 1 includes the hole injection layer 4, the hole transport layer 5, the red light-emitting layer 6, the first intermediate layer 7A, the blue light-emitting layer 8, the second intermediate layer 7B, and the green light-emitting layer 9. A stacked body 15 in which the electron transport layer 10 and the electron injection layer 11 are stacked in this order is interposed between two electrodes (between the anode 3 and the cathode 12).
The entire light emitting element 1 is provided on the substrate 2 and is sealed with a sealing member 13.

  In such a light emitting element 1, electrons are supplied (injected) from the cathode 12 side to the light emitting layers of the red light emitting layer 6, the blue light emitting layer 8, and the green light emitting layer 9, and the anode 3 side. Holes are supplied (injected). In each light emitting layer, holes and electrons recombine, and excitons (excitons) are generated by the energy released during the recombination, and energy (fluorescence or phosphorescence) is generated when the excitons return to the ground state. Therefore, the red light emitting layer 6, the blue light emitting layer 8, and the green light emitting layer 9 emit light in red, blue, and green, respectively. Thereby, the light emitting element 1 emits white light.

The substrate 2 supports the anode 3. Since the light-emitting element 1 of the present embodiment is configured to extract light from the substrate 2 side (bottom emission type), the substrate 2 and the anode 3 are substantially transparent (colorless transparent, colored transparent, or translucent), respectively. Has been.
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.
In the case where the light emitting element 1 is configured to extract light from the side opposite to the substrate 2 (top emission type), the substrate 2 can be either a transparent substrate or an opaque substrate.
Examples of the opaque substrate include a substrate made of a ceramic material such as alumina, an oxide film (insulating film) formed on the surface of a metal substrate such as stainless steel, and a substrate made of a resin material. It is done.

Hereinafter, each part which comprises the light emitting element 1 is demonstrated sequentially.
(anode)
The anode 3 is an electrode that injects holes into the hole transport layer 5 through a hole injection layer 4 described later. As a constituent material of the anode 3, it is preferable to use a material having a large work function and excellent conductivity.

Examples of the constituent material of the anode 3 include oxides such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and 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 3 is not particularly limited, but is preferably about 10 to 200 nm, and more preferably about 50 to 150 nm.

(cathode)
On the other hand, the cathode 12 is an electrode that injects electrons into the electron transport layer 10 via an electron injection layer 11 described later. As a constituent material of the cathode 12, it is preferable to use a material having a small work function.
Examples of the constituent material of the cathode 12 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 12, 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 12, the electron injection efficiency and stability of the cathode 12 can be improved.
Although the average thickness of such a cathode 12 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.
In addition, since the light emitting element 1 of this embodiment is a bottom emission type, the cathode 12 is not particularly required to have light transmittance.

(Hole injection layer)
The hole injection layer 4 has a function of improving the hole injection efficiency from the anode 3.
The hole injection layer 4 is formed using a water-based solvent or a dispersion medium film-forming ink, as will be described in detail later.
The constituent material (hole injection material) of the hole injection layer 4 is not particularly limited. For example, poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS), PEDOT / PSS / Nafion (registered trademark), polythiophene and derivatives thereof, polyaniline and derivatives thereof, polypyrrole and derivatives thereof, N, N, N ′, N′-tetraphenyl-p-diaminobenzene and derivatives thereof, and the like. One kind or a combination of two or more kinds can be used.
The average thickness of the hole injection layer 4 is not particularly limited, but is preferably about 5 to 150 nm, and more preferably about 10 to 100 nm.

(Hole transport layer)
The hole transport layer 5 has a function of transporting holes injected from the anode 3 through the hole injection layer 4 to the red light emitting layer 6.
The hole transport layer 5 is formed by using the film forming ink and the film forming method of the present invention, as will be described in detail later.
As the constituent material of the hole transport layer 5, 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 poly (2,7- (9,9-di-n-octylfluorene)-(1,4-phenylene-((4-sec-butylphenyl)). Such as those having an arylamine skeleton such as a polyarylamine such as imino) -1,4-phenylene (TFB), those having a fluorene skeleton such as a fluorene-bithiophene copolymer, and a fluorene-arylamine copolymer Having both an arylamine skeleton and a fluorene skeleton, poly (N-vinylcarbazole), polyvinylpyrene, polyvinylanthracene, polythiophene, polyalkylthiophene, polyhexylthiophene, poly (p-phenylenevinylene), polytinylenevinylene, Pyrene formaldehyde resin, ethylcarbazole form Aldehyde resins or derivatives thereof.
Such a p-type polymer material can also be used as a mixture with other compounds. 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′-bis (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 phenyl-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 such as sila Compounds, pyrrole compounds such as 1,4-dithioketo-3,6-diphenyl-pyrrolo- (3,4-c) pyrrolopyrrole, fluorene compounds such as fluorene, porphyrins, metal tetraphenylporphyrins and the like Porphyrin compounds, quinacridone compounds such as quinacridone, phthalocyanines, copper phthalocyanines, metal or metal-free phthalocyanine compounds such as tetra (t-butyl) copper phthalocyanine, iron phthalocyanines, copper naphthalocyanines, vanadyl naphthalocyanines, monochlorogallium Metallic or metal-free naphthalocyanine compounds such as naphthalocyanine, N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine, N, N, N ′, N′-tetraphenyl Benzidine like benzidine Compounds, and the like.
The average thickness of the hole transport layer 5 is not particularly limited, but is preferably about 10 to 150 nm, and more preferably about 10 to 100 nm.
The hole transport layer 5 can be omitted.

(Red light emitting layer)
The red light emitting layer (first light emitting layer) 6 includes a red light emitting material that emits red light (first color).
The red light-emitting layer 6 will be described later when the hole transport layer 5 described above is omitted or when the hole transport layer 5 is formed using a water-based solvent or a dispersion medium film-forming ink. The film forming ink and the film forming method of the present invention are used.

Such a red light emitting material is not particularly limited, and various red fluorescent materials and red phosphorescent materials can be used singly or in combination.
The red fluorescent material is not particularly limited as long as it emits red fluorescence. For example, perylene derivatives, europium complexes, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, porphyrin derivatives, Nile red, 2- (1, 1-dimethylethyl) -6- (2- (2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H-benzo (ij) quinolidin-9-yl) ethenyl)- 4H-pyran-4H-ylidene) propanedinitrile (DCJTB), 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), poly [2-methoxy-5 -(2-ethylhexyloxy) -1,4- (1-cyanovinylenephenylene)], poly [{9,9-dihexyl-2,7-bi (1-cyanovinylene) fluorenylene} ortho-co- {2,5-bis (N, N′-diphenylamino) -1,4-phenylene}], poly [{2-methoxy-5- (2-ethylhexyloxy) ) -1,4- (1-cyanovinylenephenylene)}-co- {2,5-bis (N, N′-diphenylamino) -1,4-phenylene}] and the like.

The red phosphorescent material is not particularly limited as long as it emits red phosphorescence, and examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. Among the ligands of these metal complexes, And those having at least one of phenylpyridine skeleton, bipyridyl skeleton, porphyrin skeleton and the like. More specifically, tris (1-phenylisoquinoline) iridium, bis [2- (2′-benzo [4,5-α] thienyl) pyridinate-N, C ³ ′] iridium (acetylacetonate) (btp2Ir ( acac)), 2,3,7,8,12,13,17,18-octaethyl-12H, 23H-porphyrin-platinum (II), bis [2- (2′-benzo [4,5-α] thienyl ) Pyridinate-N, C ³ '] iridium, bis (2-phenylpyridine) iridium (acetylacetonate).

Further, the red light emitting layer 6 may include a host material to which the red light emitting material is added as a guest material in addition to the above-described red light emitting material.
The host material recombines holes and electrons to generate excitons, and the exciton energy is transferred to the red light-emitting material (Forster transfer or Dexter transfer) to excite the red light-emitting material. Have In the case of using such a host material, for example, a red light-emitting material that is a guest material can be used as a dopant by doping the host material.

Such a host material is not particularly limited as long as it exhibits the functions described above with respect to the red light emitting material to be used. When the red light emitting material includes a red fluorescent material, for example, a naphthacene derivative, naphthalene, etc. Derivatives, acene derivatives such as anthracene derivatives (acene-based materials), distyrylarylene derivatives, perylene derivatives, distyrylbenzene derivatives, distyrylamine derivatives, quinolinolato-based metals such as tris (8-quinolinolato) aluminum complexes (Alq ₃ ) Complexes, triarylamine derivatives such as tetraphenylamine tetramers, oxadiazole derivatives, silole derivatives, dicarbazole derivatives, oligothiophene derivatives, benzopyran derivatives, triazole derivatives, benzoxazole derivatives, benzothiazole derivatives, Norin derivatives, 4,4'-bis (2,2'-diphenylvinyl) biphenyl (DPVBi) and the like, may be used singly or in combination of two or more of them.

When the red light emitting material (guest material) and the host material as described above are used, the content (dope amount) of the red light emitting material in the red light emitting layer 6 is preferably 0.01 to 10 wt%. More preferably, it is 1-5 wt%. Luminous efficiency can be optimized by setting the content of the red light emitting material within such a range.
The average thickness of the red light emitting layer 6 is not particularly limited, but is preferably about 10 to 150 nm, and more preferably about 10 to 100 nm.

(First intermediate layer)
The first intermediate layer 7A is provided between and in contact with the red light emitting layer 6 and the blue light emitting layer 8 described later. The first intermediate layer 7 </ b> A is substantially free of a light emitting material, and includes a red light emitting layer (first light emitting layer) 6 and a blue light emitting layer (second light emitting layer) 8. It has a function of adjusting the movement of carriers (holes and electrons) between them. With this function, the red light emitting layer 6 and the blue light emitting layer 8 can each emit light efficiently.

The constituent material of the first intermediate layer 7A is not particularly limited as long as it can exhibit the carrier adjustment function as described above, but an acene-based material, an amine-based material, or the like is preferably used. It is done.
The acene-based material is not particularly limited as long as it has an acene skeleton and exhibits the effects described above. For example, a naphthalene derivative, anthracene derivative, tetracene (naphthacene) derivative, pentacene derivative, hexacene Derivatives, heptacene derivatives and the like can be mentioned, and one or more of these can be used in combination.

The amine material used for the first intermediate layer 7A is not particularly limited as long as it has an amine skeleton and exhibits the effects described above. Of the transport materials, a material having an amine skeleton can be used, but a benzidine-based amine derivative is preferably used.
The average thickness of the first intermediate layer 7A is not particularly limited, but is preferably 1 to 100 nm, more preferably 3 to 50 nm, and further preferably 5 to 30 nm. Accordingly, the first intermediate layer 7A can reliably adjust the movement of holes and electrons between the red light emitting layer 6 and the blue light emitting layer 8 while suppressing the driving voltage.
The first intermediate layer 7A can be omitted.

(Blue light emitting layer)
The blue light emitting layer (second light emitting layer) 8 includes a blue light emitting material that emits blue light (second color).
Examples of such blue light-emitting materials include various blue fluorescent materials and blue phosphorescent materials, and one or more of these materials can be used in combination.

  The blue fluorescent material is not particularly limited as long as it emits blue fluorescence. For example, distyrylamine derivatives such as distyryldiamine compounds, fluoranthene derivatives, pyrene derivatives, perylene and perylene derivatives, anthracene derivatives, benzo Oxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthrene derivatives, distyrylbenzene derivatives, tetraphenylbutadiene, 4,4′-bis (9-ethyl-3-carbazovinylene) -1,1′-biphenyl (BCzVBi) ), Poly [(9.9-dioctylfluorene-2,7-diyl) -co- (2,5-dimethoxybenzene-1,4-diyl)], poly [(9,9-dihexyloxyfluorene-2, 7-diyl) -ortho-co- (2-me Xyl-5- {2-ethoxyhexyloxy} phenylene-1,4-diyl)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (ethylnylbenzene)] and the like. .

The blue phosphorescent material is not particularly limited as long as it emits blue phosphorescence. Examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. Specifically, bis [4 , 6-difluorophenyl pyridinium sulfonate -N, ^{C 2} '] - picolinate - iridium, tris [2- (2,4-difluorophenyl) pyridinate -N, ^{C 2']} iridium, bis [2- (3,5 - trifluoromethyl) pyridinate -N, ^{C 2} '] - picolinate - iridium, bis (4,6-difluorophenyl pyridinium sulfonate -N, ^{C 2')} iridium (acetylacetonate) and the like.
In addition to the blue light emitting material described above, the blue light emitting layer 8 may contain a host material to which the blue light emitting material is added as a guest material.
As such a host material, the same host material as described in the red light emitting layer (first light emitting layer) 6 described above can be used.

(Second intermediate layer)
The second intermediate layer 7B is provided between the blue light emitting layer 8 described above and a green light emitting layer 9 described later so as to be in contact therewith. The second intermediate layer 7 </ b> B is configured substantially without containing a light emitting material, and includes a blue light emitting layer (second light emitting layer) 8 and a green light emitting layer (third light emitting layer) 9. It has a function of adjusting the movement of carriers (holes and electrons) between them. By this function, the exciton energy transfer between the blue light emitting layer 8 and the green light emitting layer 9 can be prevented, so that the energy transfer from the blue light emitting layer 8 to the green light emitting layer 9 is suppressed, and The light emitting layer 8 and the green light emitting layer 9 can each emit light efficiently.

  As a constituent material of the second intermediate layer 7B, the second intermediate layer 7B is the same as or the same type as at least one of the host material of the blue light emitting layer 8 and the host material of the green light emitting layer 9. The material is the same as that of the host material, but is not particularly limited as long as it is configured so as to be substantially free of a light emitting material and can exhibit the carrier adjusting function as described above. Alternatively, a material containing an acene material is preferably used as the same material.

As the acene-based material, the same materials as those described for the first intermediate layer 7A described above can be used.
The thickness of the second intermediate layer 7B is not particularly limited, but is preferably about 2 nm or more and 10 nm or less, and more preferably about 3 nm or more and 7 nm or less. By setting the thickness of the second intermediate layer 7B within such a range, diffusion of excitons (holes and electrons) can be suppressed or prevented, and exciton movement can be adjusted with certainty.
The second intermediate layer 7B can be omitted.

(Green light emitting layer)
The green light emitting layer (third light emitting layer) 9 includes a green light emitting material that emits green light (third color).
Such a green light-emitting material is not particularly limited, and examples thereof include various green fluorescent materials and green phosphorescent materials, and one or more of them can be used in combination.

  The green fluorescent material is not particularly limited as long as it emits green fluorescence. For example, coumarin derivatives, quinacridone and derivatives thereof, 9,10-bis [(9-ethyl-3-carbazole) -vinylenyl] -anthracene , Poly (9,9-dihexyl-2,7-vinylenefluorenylene), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-diphenylene-vinylene-2-methoxy -5- {2-ethylhexyloxy} benzene)], poly [(9,9-dioctyl-2,7-divinylenefluorenylene) -ortho-co- (2-methoxy-5- (2-ethoxylhexyloxy) ) -1,4-phenylene)] and the like.

The green phosphorescent material is not particularly limited as long as it emits green phosphorescence, and examples thereof include metal complexes such as iridium, ruthenium, platinum, osmium, rhenium, and palladium. 2-phenylpyridine) iridium (Ir (ppy) 3), bis (2-phenyl-pyridinium sulfonate -N, ^{C 2} ') iridium (acetylacetonate), fac - tris [5-fluoro-2- (5-tri Fluoromethyl-2-pyridine) phenyl-C, N] iridium and the like.
Further, the green light emitting layer 9 may include a host material to which the green light emitting material is added as a guest material in addition to the above-described green light emitting material.
As such a host material, the same host material as described in the red light emitting layer (first light emitting layer) 6 described above can be used.

(Electron transport layer)
The electron transport layer 10 has a function of transporting electrons injected from the cathode 12 through the electron injection layer 11 to the green light emitting layer 9.
As a constituent material (electron transport material) of the electron transport layer 10, for example, a quinoline derivative such as an organometallic complex having an 8-quinolinol or its derivative such as tris (8-quinolinolato) aluminum (Alq ₃ ) as a ligand. Oxadiazole derivatives, perylene derivatives, pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorene derivatives, and the like, and one or more of these can be used in combination.
Although the average thickness of the electron carrying layer 10 is not specifically limited, It is preferable that it is about 0.5-100 nm, and it is more preferable that it is about 1-50 nm.
The electron transport layer 10 can be omitted.

(Electron injection layer)
The electron injection layer 11 has a function of improving the efficiency of electron injection from the cathode 12.
Examples of the constituent material (electron injection material) of the electron injection layer 11 include various inorganic insulating materials and various inorganic semiconductor materials.
Examples of such inorganic insulating materials include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. Of these, one or two or more of these can be used in combination. By forming the electron injection layer using these as main materials, the electron injection property can be further improved. In particular, alkali metal compounds (alkali metal chalcogenides, alkali metal halides, and the like) have a very small work function, and the light-emitting element 1 can have high luminance by forming the electron injection layer 11 using the work function. Become.

Examples of the alkali metal chalcogenide include Li ₂ O, LiO, Na ₂ S, Na ₂ Se, and NaO.
Examples of the alkaline earth metal chalcogenide include CaO, BaO, SrO, BeO, BaS, MgO, and CaSe.
Examples of the alkali metal halide include CsF, LiF, NaF, KF, LiCl, KCl, and NaCl.
Examples of the alkaline earth metal halide include CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ , and BeF ₂ .

In addition, as the inorganic semiconductor material, for example, an oxide including at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn , Nitrides, oxynitrides, and the like, and one or more of these can be used in combination.
The average thickness of the electron injection layer 11 is not particularly limited, but is preferably about 0.1 to 1000 nm, more preferably about 0.2 to 100 nm, and about 0.2 to 50 nm. Further preferred.
The electron injection layer 11 can be omitted.

(Sealing member)
The sealing member 13 is provided so as to cover the cathode 12, and has a function of hermetically sealing the anode 3, the stacked body 15, and the cathode 12, and blocking oxygen and moisture. By providing the sealing member 13, effects such as improvement in reliability of the light emitting element 1, prevention of deterioration / deterioration (improvement in durability), and the like can be obtained.

Examples of the constituent material of the sealing member 13 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 13, in order to prevent a short circuit, an insulating film is provided between the sealing member 13 and the cathode 12 as needed. Is preferred.
Further, the sealing member 13 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.

(Manufacturing method of light emitting element)
Next, the case where the ink for film formation and the film formation method of the present invention are applied to the manufacture of the light-emitting element 1 described above will be described as an example.
The above light emitting element 1 can be manufactured as follows, for example.
[1] First, the substrate 2 is prepared, and the anode 3 is formed on the substrate 2.
The anode 3 is, for example, a chemical vapor deposition method (CVD) such as plasma CVD or thermal CVD, a dry plating method such as vacuum deposition, a wet plating method such as electrolytic plating, a thermal spraying method, a sol-gel method, a MOD method, or a metal foil. It can be formed by using, for example, bonding.

[2] Next, the hole injection layer 4 is formed on the anode 3.
The hole injection layer 4 is formed by supplying a hole injection layer forming material (ink) obtained by dissolving a hole injection material in a solvent or dispersing in a dispersion medium onto the anode 3 and then drying (desolving or removing the solvent). Formed by a dispersion medium).
As a method for supplying the material for forming the hole injection layer, for example, various coating methods such as a spin coating method, a roll coating method, and an ink jet printing method (droplet discharge method) can be used. By using such a coating method, the hole injection layer 4 can be formed relatively easily.

Examples of the solvent or dispersion medium used for the preparation of the hole injection layer forming material include various inorganic solvents, various organic solvents, or mixed solvents containing these.
In addition, a high boiling point solvent may be added to such a solvent or dispersion medium in order to improve the stability of droplet discharge. Specific examples of such high-boiling solvents include aromatic hydrocarbons, isopropyl alcohol (IPA), normal butanol, γ-butyrolactone, N-methylpyrrolidone (NMP), dimethylformamide (DMF), hexamethylphossolamide ( HMPA), dimethyl sulfoxide (DMSO), 1,3-dimethyl-2-imidazolidinone (DMI) and its derivatives, glycol ethers such as carbitol acetate and butyl carbitol acetate.

The drying can be performed, for example, by standing in an atmospheric pressure or a reduced pressure atmosphere, heat treatment, or blowing an inert gas.
Prior to this step, the upper surface of the anode 3 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart lyophilicity to the upper surface of the anode 3, remove (clean) organic substances adhering to the upper surface of the anode 3, adjust the work function near the upper surface of the anode 3, and the like. .
Here, the oxygen plasma treatment conditions include, for example, a plasma power of about 100 to 800 W, an oxygen gas flow rate of about 50 to 100 mL / min, a conveyance speed of the member to be treated (anode 3) of about 0.5 to 10 mm / sec, It is preferable that the temperature of the support for supporting the treatment member is about 70 to 90 ° C.

[3] Next, the hole transport layer 5 is formed on the hole injection layer 4.
This hole transport layer 5 is formed by using a hole transport layer forming material (film-forming ink of the present invention) obtained by dissolving the above-described hole transport material in a solvent or dispersing in a dispersion medium on the hole injection layer 4. And then dried (desolvent or dedispersion medium).
In particular, as a method for supplying the hole injection layer forming material (film-forming ink), for example, an inkjet printing method (droplet discharge method) using a droplet discharge device as described later is used.

(Droplet discharge device)
Here, a droplet discharge device used for forming the hole transport layer 5 will be described.
FIG. 2 is a perspective view showing a schematic configuration of a droplet discharge device (inkjet device), and FIG. 3 is a diagram for explaining a schematic configuration of a droplet discharge head (inkjet head) provided in the droplet discharge device of FIG. FIG.

As shown in FIG. 2, the droplet discharge device 200 includes a droplet discharge head (inkjet head; hereinafter simply referred to as a head) 110, a base 130, a table 140, an ink reservoir (not shown), Table positioning means 170, head positioning means 180, and control device 190 are provided.
The base 130 is a table that supports each component of the droplet discharge device 200 such as the table 140, the table positioning unit 170, and the head positioning unit 180.

The table 140 is installed on the base 130 via the table positioning means 170. In addition, the table 140 is used for placing the base material S (in this embodiment, a laminate including the substrate 20, the anode 3, and the hole injection layer 4).
A rubber heater (not shown) is disposed on the back surface of the table 140. The base material S placed on the table 140 is heated to a predetermined temperature by a rubber heater on the entire upper surface thereof.

The table positioning unit 170 includes a first moving unit 171 and a motor 172. The table positioning means 170 determines the position of the table 140 in the base 130, and thereby determines the position of the base material S in the base 130.
The first moving means 171 has two rails provided substantially parallel to the Y direction and a support base that moves on the rails. The support base of the first moving means 171 supports the table 140 via the motor 172. Then, as the support base moves on the rail, the table 140 on which the base material S is placed is moved and positioned in the Y direction.

The motor 172 supports the table 140 and swings and positions the table 140 in the θz direction.
The head positioning unit 180 includes a second moving unit 181, a linear motor 182, and motors 183, 184 and 185. The head positioning unit 180 determines the position of the head 110.

  The second moving means 181 is provided with two support pillars standing from the base 130, a support base provided between the support pillars, the rail support having two rails, and the rails. And a support member (not shown) for supporting the head 110. Then, as the support member moves along the rail, the head 110 is moved and positioned in the X direction.

The linear motor 182 is provided in the vicinity of the support member, and can move and position the head 110 in the Z direction.
Motors 183, 184, and 185 swing and position the head 110 in the α, β, and γ directions, respectively.
By the table positioning unit 170 and the head positioning unit 180 as described above, the droplet discharge device 200 accurately determines the relative position and posture between the ink discharge surface 115P of the head 110 and the substrate S on the table 140. Can be controlled.

  As shown in FIG. 3, the head 110 discharges the film-forming ink 300 from the nozzles (protruding portions) 118 by an ink jet method (droplet discharge method). In the present embodiment, the head 110 uses a piezo method in which ink is ejected using a piezo element 113 as a piezoelectric element. The piezo method has an advantage that the composition of the material is not affected because no heat is applied to the film-forming ink 300.

The head 110 has a head body 111, a diaphragm 112, and a piezo element 113.
The head main body 111 has a main body 114 and a nozzle plate 115 on the lower end surface thereof. Then, the main body 114 is sandwiched between the plate-like nozzle plate 115 and the vibration plate 112, whereby a reservoir 116 as a space and a plurality of ink chambers 117 branched from the reservoir 116 are formed.

The reservoir 116 is supplied with film-forming ink 300 from an ink storage section (not shown). The reservoir 116 forms a flow path for supplying the film forming ink 300 to each ink chamber 117.
The nozzle plate 115 is attached to the lower end surface of the main body 114 and constitutes an ink ejection surface 115P. In the nozzle plate 115, a plurality of nozzles 118 that discharge the film-forming ink 300 are opened corresponding to the ink chambers 117. An ink flow path is formed from each ink chamber 117 toward the corresponding nozzle (ejection unit) 118.

The diaphragm 112 is attached to the upper end surface of the head body 111 and constitutes the wall surface of each ink chamber 117. The diaphragm 112 can vibrate according to the vibration of the piezo element 113.
The piezo element 113 is provided corresponding to each ink chamber 117 on the opposite side of the vibration plate 112 from the head body 111. The piezoelectric element 113 is obtained by sandwiching a piezoelectric material such as quartz with a pair of electrodes (not shown). The pair of electrodes is connected to the drive circuit 191.

When an electric signal is input from the drive circuit 191 to the piezo element 113, the piezo element 113 is expanded or contracted. When the piezoelectric element 113 contracts and deforms, the pressure in the ink chamber 117 decreases, and the film-forming ink 300 flows from the reservoir 116 into the ink chamber 117. Further, when the piezo element 113 is expanded and deformed, the pressure in the ink chamber 117 is increased and the film-forming ink 300 is ejected from the nozzle 118. Note that the amount of deformation of the piezo element 113 can be controlled by changing the applied voltage. Further, the deformation speed of the piezo element 113 can be controlled by changing the frequency of the applied voltage. That is, by controlling the voltage applied to the piezo element 113, the ejection conditions of the film-forming ink 300 can be controlled.
The control device 190 controls each part of the droplet discharge device 200. For example, by adjusting the waveform of the applied voltage generated by the drive circuit 191 to control the ejection conditions of the film-forming ink 300, or by controlling the head positioning unit 180 and the table positioning unit 170, The ejection position of the film-forming ink 300 is controlled.

(Ink for film formation)
The film-forming ink 300 of the present invention includes a film-forming material and a liquid medium in which the film-forming material is dissolved or dispersed.
The film-forming ink 300 is applied to the base material S (hole injection layer 4 in the present embodiment), and the liquid medium is removed to thereby form a film (main book) composed of the film-forming material as a main material. In the embodiment, it is used to form the hole transport layer 5). Thereby, the film | membrane (hole transport layer 5 in this embodiment) or its precursor film | membrane used as the objective of film-forming can be formed.

  In particular, the film-forming ink 300 is used for film formation using the droplet discharge device 200 as described above, that is, film formation by the droplet discharge method. Thereby, the film-forming ink 300 can be applied to a desired position and region even in a fine region. In addition, the droplet discharge method has an advantage that the film forming process is simpler than the vapor phase film forming method, and the amount of raw material (film forming material) used is small.

Hereinafter, each component of the film-forming ink 300 of the present invention will be described in detail.
(Deposition material)
The film-forming material contained in the film-forming ink 300 of the present invention is a constituent material or a precursor of a film intended for film formation (in this embodiment, the hole transport layer 5).
In the film-forming ink 300, the film-forming material may be dissolved or dispersed in a liquid medium described later, but the film-forming material is a liquid medium. In the case of being dispersed in the film, the average particle diameter of the film forming material is preferably 20 to 200 nm, and more preferably 5 to 90 nm. Thereby, the dispersion stability of the film forming material in the film forming ink 300 can be made excellent.

The film forming material is preferably soluble in a non-aqueous solvent. Such a film forming material can be dissolved in a liquid medium. Therefore, even when a polymer material is used as a film forming material, a homogeneous film can be formed.
In the present embodiment, the film forming material used in this step is a material constituting the hole transport layer of the organic electroluminescence element or a precursor thereof.

  In the light emitting element 1 described above, the hole injection layer 4 is provided on the anode 3, and the hole transport layer 5 is provided on the hole injection layer 4. When the hole transport layer 5 is formed, the constituent material of the hole transport layer 5 or the precursor thereof is non-aqueous based on the hole injection layer 4 formed using an aqueous solvent or dispersion medium. The film-forming ink 300 dissolved or dispersed in a solvent or dispersion medium is applied.

Therefore, when the film-forming ink 300 of the present invention is used for forming the hole transport layer 5, the effect of the present invention becomes remarkable.
In the light emitting element 1, the hole transport layer 5 can be omitted as described above. Therefore, in that case, a light emitting layer (red light emitting layer 6) is provided on the hole injection layer 4. In this case, when the red light emitting layer 6 is formed, a constituent material of the red light emitting layer 6 or a precursor thereof is dissolved or dispersed in a non-aqueous solvent or dispersion medium on the hole injection layer 4. The film ink is applied. Therefore, even if the film-forming ink of the present invention is used to form such a red light emitting layer 6, the effect of the present invention becomes remarkable.

  The content rate of the film forming material in the film forming ink 300 is determined according to the use of the film forming ink 300 and is not particularly limited, but is preferably 0.01 to 20 wt%, for example. More preferably, it is 0.05-15 wt%. When the content of the film forming material is within the above range, the discharge property (discharge stability) from the film forming droplet discharge head (inkjet head) can be made particularly excellent.

(Liquid medium)
The liquid medium contained in the film-forming ink 300 of the present invention is one that dissolves or disperses the film-forming material described above, that is, a solvent or a dispersion medium. Most of the liquid medium is removed in the film forming process described later.
In particular, such a liquid medium has an ether compound having a surface tension of 35 dyn / cm ² or less and represented by the following formula (I).

［上記式（Ｉ）において、Ｒ_１およびＲ_２は、それぞれ、炭素数１以上４以下の直鎖アルキル基、分岐アルキル基または環状アルキル基である。Ｒ_３は、炭素数１以上３以下のアルキレン基である。また、ｎは、０以上４以下の整数である。また、ｎが２以上である場合、Ｒ_３は互いに同じであっても異なっていてもよい。］

[In the above formula (I), R ₁ and R ₂ are each a linear alkyl group, branched alkyl group or cyclic alkyl group having 1 to 4 carbon atoms. R ₃ is an alkylene group having 1 to 3 carbon atoms. N is an integer of 0 or more and 4 or less. When n is 2 or more, R ₃ may be the same as or different from each other. ]

According to the film-forming ink 300 configured as described above, when a non-aqueous solvent or dispersion medium is used, a layer formed using an aqueous solvent or dispersion medium (in this embodiment, a hole injection layer). 4) It can be easily wetted and spread.
In addition, since the film-forming ink of the present invention does not require the use of an additive such as a surfactant, the film characteristics can be prevented from deteriorating due to the additive remaining in the obtained film.

  In particular, the ether compound used in the film-forming ink 300 is optimized in the number of ether oxygen atoms and the number of carbon atoms, and does not contain hetero atoms other than ether oxygen atoms (that is, polar groups other than ether groups ( For example, it does not contain esters, acetates, ketones, hydroxyl groups, carboxyl groups, sulfo groups), so that it can be used as a non-aqueous solvent or dispersion medium and the resulting film (hole transport layer 5 in this embodiment) Even if it remains in, the adverse effect on the electrical characteristics of the film can be reduced. Furthermore, such a compound has a low aggressiveness with respect to the film forming material (in this embodiment, a hole transporting material), and in this respect as well, deterioration of characteristics of the obtained film can be prevented.

On the other hand, if the surface tension of the liquid medium contained in the film-forming ink 300 is larger than 35 dyn / cm ² , the film-forming ink 300 is uniformly spread over the hole injection layer 4. I can not let you.
Further, in order to improve the wettability of the film-forming ink 300 on the hole injection layer 4, the surface tension of the liquid medium contained in the film-forming ink 300 is 30 dyn / cm ² or less. Is preferred.

  In addition, in the above formula (I), if n is 0 or 1, the boiling point of the liquid medium (ether compound) becomes too low, and as a result, for example, droplet discharge used in the droplet discharge method The nozzle of the head is clogged. On the other hand, in the above formula (I), if n is 5 or more, the viscosity of the liquid medium (ether compound) becomes too high, and as a result, it is formed using an aqueous solvent or dispersion medium. The ink for film formation on the layer (film) cannot be uniformly applied and spread, or the boiling point of the liquid medium (ether compound) becomes too high. Or the dedispersion medium property may fall.

  From such a viewpoint, in the formula (I), n is preferably 2 or more and 4 or less. That is, the ether compound represented by the formula (I) preferably has 3 or more and 5 or less ether bonds. Thereby, both the wettability of the film-forming ink 300 on the layer (film) formed using an aqueous solvent or dispersion medium and the desolvation property or the de-dispersion medium property of the film-forming ink 300 are excellent. Can be. Further, it is possible to prevent the boiling point of the liquid medium (ether compound) from becoming too low, and as a result, it is possible to prevent clogging of a nozzle of a droplet discharge head used in a droplet discharge method, for example.

In the formula (I), when n is 2 or more and 4 or less, R ₃ preferably has 2 or 3 carbon atoms. Accordingly, when the film forming material is soluble in a non-aqueous solvent, the film forming material is surely dissolved in the liquid medium and the liquid medium is not intended (for example, a droplet discharge method) It is possible to prevent or suppress the dissolution of the member constituting the droplet discharge head used in the above.

On the other hand, in the formula (I), if the number of carbon atoms in R ₃ is too small, the solubility of the nonpolar material in the liquid medium is too high and the liquid medium dissolves an unintended one. There is a case. On the other hand, in the formula (I), if R ₃ has too many carbon atoms, the wettability of the film-forming ink 300 on the layer (film) formed using an aqueous solvent or dispersion medium, and film formation It is difficult to achieve both the solvent removal property or the dedispersion medium property of the ink 300 for use.

  The content of the ether compound in the liquid medium is preferably 0.1% to 100 wt%, more preferably 10% to 100 wt%, and more preferably 20% to 100 wt%. More preferably. Thereby, the wettability of the film-forming ink 300 on the layer (film) formed using an aqueous solvent or dispersion medium can be improved.

  The liquid medium may contain a compound other than the compound represented by the above formula (I). Examples of compounds that can be contained in the liquid medium include naphthalene derivatives such as naphthalene and dimethylnaphthalene, benzene (Benzene, boiling point 80.1 ° C, melting point 5.5 ° C), toluene (Toluene, boiling point 110.6 ° C, melting point -93 ° C), o -Xylene (o-Xylene (p-, m-), boiling point 144 ° C, melting point -25 ° C), trimethylbenzene (Trimethylbenzene, boiling point 165 ° C, melting point -45 ° C), tetralin (tetrahydronaphthalene: Tetralin, boiling point 208 ° C) Melting point-35.8 ° C), cyclohexylbenzene (cyclohexylbenzene, boiling point 237.5 ° C, melting point 5 ° C), 1,4-dichlorobenzene (1,4-dchlorobenzene, boiling point 174 ° C, melting point 53.5 ° C), 1,2,3-trichlorobenzene (1,2,3-Trichlorobenzene, boiling point 221 ° C, melting point 52.6 ° C), tetrahydrofuran (Tetrahydrofuran, boiling point 66 ° C, melting point -108.5 ° C), diethyl ether (diethyl ether, boiling point 35 ° C, melting point -116 ° C), diisopropyl ether (Diisopropyl ether, boiling point 69 ° C, melting point -85.6 ° C), ethylene glycol (ethylene glycol, boiling point 197.3 ° C, melting point -12.9 ° C), ethylene glycol diethyl ether (Ethylene glycol diethyl ether, boiling point 190 ° C, melting point -44.3 ° C), Dioxane (Dioxane, boiling point 101.1 ° C, melting point 11.8 ° C), Anisole (methoxybenzene: Anisole, boiling point 154 ° C, melting point -37 ° C), Dichloromethane (dichloromethane, boiling point 40 ° C, melting point -96.7 ° C), Trichloromethane, boiling point 61.2 ℃, melting point -64 ℃), carbon tetrachloride (tetrachloromethane, boiling point 76.7 ℃, melting point -28.6 ℃), pentane (pentane, boiling point 36 ℃, melting point -131 ℃), hexane (Hexane, boiling point 69 ℃, melting point) -95 ° C), cyclohexane (cyclohexane, boiling point 81 ° C, melting point 7 ° C), acetone (Acetone, boiling point 56.5 ° C, melting point -94 ° C), 1-methyl-2-pyrrolidinone (NMP: 1-Methyl-2-pyrrolidinone, Boiling point 204 ° C, -24 ° C), methylethylketone (boiling point 79.6 ° C, melting point -86 ° C), alpha-tetralone (both 257 ° C, melting point 7 ° C), cyclohexanone (Cyclohexanone, boiling point 157 ° C, melting point -45 ° C) , Ethyl acetate (boiling point 77.1 ℃, melting point -83.6 ℃), butyl acetate (butyl acetate, boiling point 126 ℃, melting point -74 ℃), methanol (methanol, boiling point 67 ℃, melting point -97 ℃), ethanol (ethanol , Boiling point 78.4 ° C, melting point -114.3 ° C), isopropyl alcohol (isopropyl alcohol, boiling point 82.4 ° C, melting point -89.5 ° C), 1-propanol (1-Propanol, boiling point 97.15 ° C, melting point -126.5 ° C), acetonitrile (acetonitrile, boiling point) 82 ° C, melting point -45 ° C), N, N-dimethylformamide (DMF: N, N-dimethylformamide, boiling point 153 ° C, melting point -61 ° C), N, N-dimethylacetamide (DMAc: N, N-dimethylacetamide, boiling point) 165 ° C, melting point -20 ° C), 1, -Dimethyl-2-imidazolidinone (1,3-dimethyl-2-imidazolidinone, boiling point 220 ° C., melting point 8 ° C.), dimethyl sulfoxide (boiling point 189 ° C., melting point 18.5 ° C.), 4-tert-butylanisole ( 4-tert-Butylanisole, boiling point 222 ° C, melting point 18 ° C, Trans-Anethole (Trans-Anethole, boiling point 235 ° C, melting point 20 ° C), 1,2-dimethoxybenzene (1,2-Dimethoxybenzene, boiling point 206.7 ° C, melting point) 22.5 ° C), 2-Methoxybiphenyl (boiling point 274 ° C, melting point 28 ° C), phenyl ether (Phenyl Ether, boiling point 258.3 ° C, melting point 28 ° C), 2-ethoxynaphthalene (2-Ethoxynaphthalene, boiling point 282 ° C), Melting point 35 ° C), benzyl phenyl ether (Benzyl Phenyl Ether, boiling point 288 ° C, melting point 39 ° C), 2,6-dimethoxytoluene (2,6-Dimethoxytoluene, boiling point 222 ° C, melting point 39 ° C), 2-propoxynaphthalene (2 -Propoxynaphthalene, boiling point 305 ℃, melting point 40 ° C), 1,2,3-trimethoxybenzene (1,2,3-Trimethoxybenzene, boiling point 235 ° C, melting point 45 ° C), 1,4-dichlorobenzene (1,4-dichlorobenzene, boiling point 174 ° C, melting point 53.5) ° C) and the like, and one or more of these can be used in combination.

  Moreover, it is preferable to use an aromatic hydrocarbon compound as a compound other than the compound represented by the above formula (I). That is, the liquid medium preferably contains an aromatic hydrocarbon compound in addition to the ether compound. Thus, when the film forming material is soluble in a non-aqueous solvent, the film forming material is surely dissolved in the liquid medium, and when the film forming ink 300 is manufactured, the ether compound and Depending on the mixing ratio with the aromatic hydrocarbon compound, a liquid medium having a desired surface tension can be easily prepared.

The viscosity (hereinafter also simply referred to as “viscosity”) of the liquid medium at normal temperature (20 ° C.) is preferably 4 cP or less, and more preferably 2 cP or less. Thereby, the wettability of the film-forming ink 300 on the layer (in this embodiment, the hole injection layer 4) formed using an aqueous solvent or dispersion medium can be effectively enhanced.
The boiling point of the liquid medium at normal pressure is preferably 80 ° C. or higher and 350 ° C. or lower, more preferably 160 ° C. or higher and 300 ° C. or lower, and further preferably 200 ° C. or higher and 280 ° C. or lower. . Thereby, the volatility of the liquid medium of the film-forming ink 300 can be suppressed, and the film-forming ink 300 can be stably discharged using the droplet discharge method. In addition, it is possible to make the film-forming ink excellent in desolvation property or dedispersion medium property.

The content of such a liquid medium in the film-forming ink 300 is preferably 80 to 99.99 wt%, and more preferably 85 to 99.95 wt%.
The film forming ink as described above is used for film formation using an ink jet method (droplet discharge method) as described later. According to the inkjet method, fine patterning can be performed relatively easily and reliably.

Such a film-forming ink forms a liquid in an ink application process [3-1] described later.
The viscosity of such a film-forming ink is not particularly limited, but is preferably about 1 cP or more and 5 cP or less. By adjusting the viscosity of the film-forming ink within such a range, the effect of reducing the viscosity of the liquid medium as described above becomes remarkable.
The hole transport layer 5 is formed using the droplet discharge device 200 and the film-forming ink 300 as described above.

(Film formation method)
Specifically, the formation method (film formation method) of the hole transport layer 5 includes [3-1] a step of applying a film formation ink onto the substrate S (specifically, the hole injection layer 4). And [3-2] removing the liquid medium from the film-forming ink to form the hole transport layer 5.
Thus, when a non-aqueous solvent or dispersion medium is used, the layer formed using the aqueous solvent or dispersion medium can be easily wetted without using an additive such as a surfactant. Can be expanded. As a result, a film having excellent film quality can be formed easily and in a short time.

[3-1]
Specifically, a desired amount of film-forming ink 300 is applied onto the hole injection layer 4 by using the droplet discharge device 200 described above.
The temperature and pressure of the atmosphere in this step [3-1] are respectively determined according to the composition of the film-forming ink 300, and if the film-forming ink 300 can be applied onto the substrate S, Although not particularly limited, it is preferably normal temperature and pressure. Thereby, the deposition ink 300 can be easily applied.

[3-2]
Then, a film-forming ink formed on the substrate S (in this embodiment, a laminate comprising the substrate 20, the anode 3 and the hole injection layer 4 and specifically on the hole injection layer 4). By removing the liquid medium from 300, a film containing the film forming material as a main component (that is, the hole transport layer 5 or its precursor film) is obtained.
The temperature and pressure of the atmosphere in this step [3-2] are determined according to the composition of the film-forming ink 300, and the liquid medium is removed from the film-forming ink 300 on the substrate S. Although it is not particularly limited as long as it is possible, the removal of the liquid medium is preferably performed under heating and reduced pressure. Thereby, the liquid medium can be efficiently removed from the film-forming ink 300.

This heating is not particularly limited, but can be performed with a hot plate or infrared rays. Further, this heating may be performed by a rubber heater provided on the table 140 of the droplet discharge device 200 described above.
Although this heating temperature is not specifically limited, It is preferable that it is about 60-100 degreeC.
Moreover, although heating time is not specifically limited, It is about 1 minute or more and 60 minutes or less.

As described above, when the pressure is reduced, the pressure is not particularly limited, but is preferably about 10 ⁻⁷ Pa to 10 Pa.
The film formed by removing the liquid medium in this way is composed of the constituent material of the hole transport layer 5 to be formed or a precursor thereof.
When the precursor of the constituent material of the hole transport layer 5 is used as the film forming material, the film obtained by removing the liquid medium is subjected to a predetermined treatment as necessary. For example, heat treatment (baking treatment) is performed in an inert gas atmosphere.
Although this heating temperature is not specifically limited, It is preferable that it is about 100-200 degreeC.
The heating time is not particularly limited, but is about 10 minutes to 2 hours.
As described above, the hole transport layer 5 is formed.

[4] Next, the red light emitting layer 6 is formed on the hole transport layer 5.
The red light emitting layer 6 can be formed by a vapor phase process using, for example, a CVD method, a dry plating method such as vacuum deposition or sputtering, or the like.
In addition, the red light emitting layer 6 is dried (desolvent or dehydrated) after supplying a material for forming a red light emitting layer obtained by, for example, dissolving a constituent material in a solvent or dispersing in a dispersion medium onto the hole transport layer 5. It can also be formed by using a dispersion medium.
In addition, this red light emitting layer 6 was mentioned above, when the hole transport layer 5 mentioned above was abbreviate | omitted, or when the hole transport layer 5 was formed using the film-forming ink of an aqueous solvent or a dispersion medium. It is formed using the film-forming ink and film-forming method of the present invention in the same manner as the formation of the hole transport layer 5.

[5] Next, the first intermediate layer 7 </ b> A is formed on the red light emitting layer 6.
The first intermediate layer 7A can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like.
In addition, the first intermediate layer 7A is supplied with a first intermediate layer forming material obtained by, for example, dissolving a constituent material in a solvent or dispersed in a dispersion medium on the red light-emitting layer 6 and then dried (desorbed). (Solvent or dedispersing medium).

[6] Next, the blue light emitting layer 8 is formed on the first intermediate layer 7A.
The blue light emitting layer 8 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering.
[7] Next, the second intermediate layer 7 </ b> B is formed on the blue light emitting layer 8.
The second intermediate layer 7B is formed using the same method as the method for forming the first intermediate layer 7A described in the step [5].

[8] Next, the green light emitting layer 9 is formed on the second intermediate layer 7B.
The green light emitting layer 9 can be formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or the like.
[9] Next, the electron transport layer 10 is formed on the green light emitting layer 9.
The electron transport layer 10 can be formed by a vapor phase process using, for example, a CVD method, a dry plating method such as vacuum deposition, sputtering, or the like.
Further, the electron transport layer 10 is dried (desolvent or dedispersed) after supplying an electron transport layer forming material obtained by, for example, dissolving an electron transport material in a solvent or dispersing in a dispersion medium onto the green light emitting layer 9. It can also be formed by the medium.

[10] Next, the electron injection layer 11 is formed on the electron transport layer 10.
When an inorganic material is used as the constituent material of the electron injection layer 11, the electron injection layer 11 is formed by, for example, a vapor phase process using a CVD method, a dry plating method such as vacuum deposition or sputtering, or coating and baking of inorganic fine particle ink. Etc. can be used.
[11] Next, the cathode 12 is formed on the electron injection layer 11.
The cathode 12 can be formed using, for example, a vacuum evaporation method, a sputtering method, bonding of metal foil, application and baking of metal fine particle ink, and the like.
The light emitting element 1 is obtained through the steps as described above.

Finally, a sealing member 13 is formed so as to cover the obtained light emitting element 1.
According to the manufacturing method of the light emitting element 1 as described above, since the steps [3-1] and [3-2] as described above are included, the film-forming ink using a non-aqueous solvent or dispersion medium is used. In the case of forming the hole transport layer 5, such film formation can be performed on the hole injection layer 4 formed using an aqueous solvent or dispersion medium without using an additive such as a surfactant. The ink 300 can be easily wetted and spread. As a result, the hole transport layer 5 having excellent film quality can be formed easily and in a short time. In particular, since the surfactant does not remain in the light emitting element 1, the characteristics of the light emitting element 1 can be improved. Moreover, the light emitting element 1 can be manufactured at low cost.

The light emitting element 1 as described above can be used as, for example, a light source. Moreover, a display apparatus (display apparatus) can be comprised by arrange | positioning the several light emitting element 1 in matrix form.
The driving method of the display device is not particularly limited, and may be either an active matrix method or a passive matrix method.

(Display device)
Next, an example of a display device including the light emitting device of the present invention will be described.
FIG. 4 is a longitudinal sectional view showing an embodiment of a display device including the light emitting device of the present invention.
The display device 100 shown in FIG. 4 includes a substrate 21, a plurality of light emitting elements 1R, 1G, and 1B and color filters 19R, 19G, and 10B provided corresponding to the sub-pixels 100R, 100G, and 100B, and each light emitting element 1R. And a plurality of driving transistors 24 for driving 1G and 1B, respectively. Here, the display device 100 is a display panel having a top emission structure.

A plurality of driving transistors 24 are provided on the substrate 21, and a planarizing layer 22 made of an insulating material is formed so as to cover these driving transistors 24.
Each driving transistor 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. H.245.
On the planarization layer, light emitting elements 1R, 1G, and 1B are provided corresponding to the driving transistors 24, respectively.

  In the light emitting element 1 </ b> R, a reflective film 32, a corrosion prevention film 33, an anode 3, a laminate (organic EL light emitting unit) 15, a cathode 12, and a cathode cover 34 are laminated in this order on a planarization layer 22. In the present embodiment, the anode 3 of each light emitting element 1R, 1G, 1B constitutes a pixel electrode and is electrically connected to the drain electrode 245 of each driving transistor 24 by a conductive portion (wiring) 27. Moreover, the cathode 12 of each light emitting element 1R, 1G, 1B is a common electrode.

The configurations of the light emitting elements 1G and 1B are the same as the configuration of the light emitting element 1R. In FIG. 4, the same reference numerals are given to the same configurations as those in FIG. 1. Further, the configuration (characteristics) of the reflective film 32 may be different among the light emitting elements 1R, 1G, and 1B depending on the wavelength of light.
A partition wall 31 is provided between the adjacent light emitting elements 1R, 1G, and 1B. An epoxy layer 35 made of an epoxy resin is formed on the light emitting elements 1R, 1G, and 1B so as to cover them.

Since the light emitting device 101 includes the light emitting elements 1R, 1G, and 1B having the same configuration as the light emitting element 1 described above, the light emitting device 101 is inexpensive and has excellent light emission characteristics.
The color filters 19R, 19G, and 19B are provided on the epoxy layer 35 described above corresponding to the light emitting elements 1R, 1G, and 1B.
The color filter 19R converts the white light W from the light emitting element 1R into red. The color filter 19G converts the white light W from the light emitting element 1G into green. The color filter 19B converts the white light W from the light emitting element 1B into blue. By using such color filters 19R, 19G, and 19B in combination with the light emitting elements 1R, 1G, and 1B, a full color image can be displayed.

A light shielding layer 36 is formed between the adjacent color filters 19R, 19G, and 19B. Thereby, it is possible to prevent the unintended subpixels 100R, 100G, and 100B from emitting light.
A substrate 20 is provided on the color filters 19R, 19G, 19B and the light shielding layer 36 so as to cover them.

The display device 100 as described above may be a single color display, and color display is also possible by selecting a light emitting material used for each light emitting element 1R, 1G, 1B.
Such a display device 100 (display device) 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 100 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 cellular phone 1200, the display unit is configured by the display device 100 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 100 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.
According to the electronic devices as described above, each of the display devices 100 (light emitting devices 101) as described above has excellent reliability.

  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, 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 described above, the film forming ink, the film forming method, the light emitting element manufacturing method, the light emitting element, the light emitting device, and the electronic apparatus according to the present invention have been described based on the illustrated embodiments, but the present invention is not limited thereto. Not.
For example, in the above-described embodiment, the light emitting element has three light emitting layers. However, the light emitting layer may be one layer, two layers, or four or more layers. For example, in the embodiment described above, one or two light emitting layers of the light emitting element may be omitted, or one or more other light emitting layers may be added. Further, the emission color of the light emitting layer is not limited to R, G, and B in the above-described embodiment.

In addition, the light emitting material used for the light emitting layer provided in contact with the hole injection layer or the hole transport layer is not limited to the red light emitting material, for example, a blue light emitting material, a green light emitting material, a yellow light emitting material, and the like. Also good.
In the above-described embodiment, the example in which the light-emitting device is incorporated in the display device has been described. However, the light-emitting device of the present invention is not limited to this, for example, electrochromic light control glass, electronic paper, lighting device, electronic It can also be used as a light source for an exposure apparatus of a photographic printer.

  Further, in the above-described embodiment, the case where the film-forming ink and the film-forming method of the present invention are applied to the manufacture of an organic EL element has been described as an example. It is not limited to. However, when the film-forming ink and the film-forming method of the present invention are applied to a film formed using a non-aqueous solvent or dispersion medium on a layer formed using an aqueous solvent or dispersion medium, Since the effect becomes remarkable, it is preferable.

Next, specific examples of the present invention will be described.
1. Preparation of liquid medium Sample No. 1-No. 27 liquid media (solvents) were prepared.
[Sample No. 1]
With respect to dimethylnaphthalene (bp: 268, surface tension 37 dyn / cm ² ), the compound represented by the formula (I) (n = 1, carbon number of R ₁ = 1, carbon number of R ₂ = 1, R ₃ A mixed solvent prepared by adding ethylene glycol dimethyl ether (bp: 85 ° C., surface tension 23 dyn / cm ² ) having carbon number = 2) so that the surface tension is 35 dyn / cm 2.

[Sample No. 2]
Diethylene glycol dimethyl ether (bp: 162 ° C., surface tension 28 dyn) which is a compound represented by the formula (I) (n = 2, carbon number of R ₁ = 1, carbon number of R ₂ = 1, carbon number of R ₃ = 2) / Cm ² ) single solvent [Sample No. 3]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 2 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 4]
Diethylene glycol ethyl methyl ether (bp: 176 ° C., surface) which is a compound represented by the formula (I) (n = 2, carbon number of R ₁ = 2, carbon number of R ₂ = 1, carbon number of R ₃ = 2) Single solvent with a tension of 27 dyn / cm ² [Sample No. 5]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding the liquid medium No. 4 and having a surface tension of 35 dyn / cm 2

[Sample No. 6]
Diethylene glycol isopropyl methyl ether (bp: 179 ° C., surface) which is a compound represented by the formula (I) (n = 2, carbon number of R ₁ = 3, carbon number of R ₂ = 1, carbon number of R ₃ = 2) Single solvent with a tension of 24 dyn / cm ² [Sample No. 7]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 6 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 8]
Diethylene glycol diethyl ether (bp: 188 ° C., surface tension) which is a compound represented by the formula (I) (n = 2, R ₁ carbon number = 2, R ₂ carbon number = 2, R ₃ carbon number = 2) 30 dyn / cm ² ) single solvent [Sample No. 9]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 8 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 10]
Diethylene glycol butyl methyl ether (bp: 212 ° C., surface) which is a compound represented by the formula (I) (n = 2, carbon number of R ₁ = 4, carbon number of R ₂ = 1, carbon number of R ₃ = 2) Single solvent with a tension of 24 dyn / cm ² [Sample No. 11]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 10 liquid media and having a surface tension of 35 dyn / cm 2

[Sample No. 12]
Diethylene glycol dibutyl ether (bp: 256 ° C., surface tension) which is the compound represented by the formula (I) (n = 2, carbon number of R ₁ = 4, carbon number of R ₂ = 4, carbon number of R ₃ = 2) 25 dyn / cm ² ) single solvent [Sample No. 13]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 12 liquid media and having a surface tension of 35 dyn / cm 2

[Sample No. 14]
Dipropylene glycol dimethyl ether (bp: 171 ° C., surface) which is a compound represented by the formula (I) (n = 2, carbon number of R ₁ = 1, carbon number of R ₂ = 1, carbon number of R ₃ = 3) Single solvent with a tension of 26 dyn / cm ² [Sample No. 15]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 14 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 16]
Triethylene glycol dimethyl ether (bp: 216 ° C., surface) which is a compound represented by the formula (I) (n = 3, carbon number of R ₁ = 1, carbon number of R ₂ = 1, carbon number of R ₃ = 2) Single solvent with a tension of 31 dyn / cm ² [Sample No. 17]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 16 liquid media and having a surface tension of 35 dyn / cm 2

[Sample No. 18]
Triethylene glycol ethyl methyl ether (bp: 225 ° C.) which is a compound represented by the formula (I) (n = 3, carbon number of R ₁ = 2, carbon number of R ₂ = 1, carbon number of R ₃ = 2) , Surface tension 29 dyn / cm ² ) single solvent [Sample No. 19]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 18 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 20]
Triethylene glycol butyl methyl ether (bp: 261 ° C.) which is a compound represented by the formula (I) (n = 3, R ₁ carbon number = 4, R ₂ carbon number = 1, R ₃ carbon number = 2) , A single solvent with a surface tension of 28 dyn / cm ² [Sample No. 21]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 20 liquid media and having a surface tension of 35 dyn / cm 2

[Sample No. 22]
Tripropylene glycol dimethyl ether (bp: 215 ° C., surface) which is a compound represented by the formula (I) (n = 3, carbon number of R ₁ = 1, carbon number of R ₂ = 1, carbon number of R ₃ = 3) Single solvent with a tension of 26 dyn / cm ² [Sample No. 23]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 22 liquid media and having a surface tension of 35 dyn / cm 2

[Sample No. 24]
Tetraethylene glycol dimethyl ether (bp: 275 ° C., surface) which is a compound represented by the formula (I) (n = 4, R ₁ carbon number = 1, R ₂ carbon number = 1, R ₃ carbon number = 2) Single solvent with a tension of 33 dyn / cm ² [Sample No. 25]
For dimethylnaphthalene, sample no. A mixed solvent prepared by adding 24 liquid medium and having a surface tension of 35 dyn / cm 2

[Sample No. 26]
Single solvent of dimethylnaphthalene [Sample No. 27]
For dimethylnaphthalene, sample no. 24 mixed medium prepared by adding a liquid medium and having a surface tension of 36 dyn / cm ² Table 1 shows a summary of the liquid media.

2. Production of light emitting device (Example 1)
<1> First, a transparent glass substrate having an average thickness of 0.5 mm was prepared. Next, an ITO electrode (anode) having an average thickness of 100 nm was formed on the substrate by sputtering.
And after immersing a board | substrate in order of acetone and 2-propanol and ultrasonically cleaning, the oxygen plasma process was performed.

<2> Next, a hole injection layer having an average thickness of 50 nm was formed on the ITO electrode.
This hole injection layer is formed by applying a film-forming ink for forming a hole injection layer onto the ITO electrode by a droplet discharge method, and after vacuum drying, heat treatment (baking treatment) in a nitrogen atmosphere at 150 ° C. for 30 minutes. ) To form.
The film forming ink for forming the hole injection layer uses PEDOT / PSS (1/20) as a film forming material, and 3,4-polyethylene which is a polystyrene sulfonic acid and a polythiophene derivative as a liquid medium (dispersion medium). A mixed dispersion medium composed of dioxythiophene and water was used.

<3> Next, a hole transport layer having an average thickness of 50 nm was formed on the hole injection layer.
This hole transport layer is formed by forming a hole transport layer forming film ink (film forming ink of the present invention) by a droplet discharge method using a droplet discharge device as shown in FIG. The film was formed by applying heat treatment (baking treatment) at 180 ° C. for 1 hour under a nitrogen atmosphere. The obtained layer (hole transport layer) became unnecessary for the organic medium.
The film forming ink for forming the hole transport layer uses TFB (0.9 wt%) as a film forming material, and the sample No. 1 as a liquid medium (solvent). 1 liquid medium (mixed solvent) was used.
When such a film-forming ink was applied on the hole injection layer, it could be spread uniformly.

<4> Next, a red light emitting layer (first light emitting layer) having an average thickness of 60 nm was formed on the hole transport layer.
This red light-emitting layer is formed by applying a film-forming ink for forming a red light-emitting layer on the hole transport layer by a droplet discharge method, followed by heat treatment (baking treatment) at 130 ° C. for 30 minutes after vacuum drying. Formed.
As the film forming ink for forming the red light emitting layer, diindenoperylene (1.5 wt%) which is a red light emitting material was used as a film forming material, and dimethylnaphthalene was used as a liquid medium (solvent).

<5> Next, a Ca layer having an average thickness of 10 nm and an Al layer having an average thickness of 200 nm are sequentially stacked on the red light-emitting layer using a vacuum deposition method (degree of vacuum 1.33 × 10 ⁻⁴ Pa). Thus, a cathode composed of these laminates was formed.
The light emitting device was manufactured through the above steps.

(Examples 2 to 25, Comparative Examples 1 and 2)
In forming the hole transport layer, as a liquid medium (solvent), the above sample No. Sample No. 1 shown in Table 2 instead of the liquid medium (mixed solvent) of No. 1 A light emitting device was produced in the same manner as in Example 1 except that the liquid medium was used.

(Example 26)
A light emitting device was manufactured in the same manner as in Example 1 except that the formation of the hole transport layer was omitted and the method for forming the red light emitting layer was different.
In this embodiment, the red light emitting layer is formed by forming a hole for the red light emitting layer forming ink (film forming ink of the present invention) by a droplet discharging method using a droplet discharging apparatus as shown in FIG. It was formed on the injection layer by vacuum treatment, followed by heat treatment (baking treatment) at 130 ° C. for 30 minutes in a nitrogen atmosphere.

The film-forming ink for forming the red light-emitting layer uses diindenoperylene (1.5 wt%), which is a red light-emitting material, as a film-forming material. 1 liquid medium (mixed solvent) was used.
When such a film-forming ink was applied on the hole injection layer, it could be spread uniformly.

(Examples 27 to 50, Comparative Examples 3 and 4)
In forming the red light emitting layer, the sample No. 1 was used as a liquid medium (solvent). 1 instead of the liquid medium (mixed solvent) of Sample No. 1 shown in Table 3. A light emitting device was manufactured in the same manner as in Example 27 except that the liquid medium was used.

3. Evaluation <Evaluation of wettability>
In the production of the light emitting device of each example and each comparative example, good results were obtained for the wettability with respect to the lower layer (on the hole injection layer) of the film forming ink used for forming the hole transport layer or the red light emitting layer. ”, Those that were not good were evaluated as“ x ”.

<Evaluation of light emission state>
For each of the light emitting devices of each example and each comparative example, a current density of 30 mA / cm ² was passed between the anode and the cathode by a direct current power source, and the light emitting state of the light emitting device was observed. Evaluated.
○: Uniform and uniform light emission was obtained.
X: The part which does not light-emit was comparatively large, and became light emission with unevenness.

<Evaluation of luminous efficiency>
A light-emitting device of Examples and Comparative Examples, was passed a constant current of 30 mA / cm ² to the light-emitting device using a DC power source. At that time, luminance was measured using a luminance meter, and luminous efficiency (luminance / current density) was evaluated. The luminous efficiency was evaluated by standardizing Examples 1 to 25 and Comparative Examples 1 and 2 on the basis of Comparative Example 1, and comparing Examples 26 to 50 and Comparative Examples 3 and 4 with Comparative Example 3. Was evaluated based on the standard.

The evaluation results are shown in Tables 2 and 3.
As is clear from Tables 2 and 3, in each example, the wettability of the film-forming ink on the hole injection layer is good, and the time required for applying the film-forming ink can be shortened. It was. Moreover, the light emitting element of each Example obtained uniform and favorable light emission.
On the other hand, in each comparative example, the wettability of the film-forming ink on the hole injection layer was poor, and the time required for applying the film-forming ink was long. In addition, the light emitting elements of the respective comparative examples had nonuniform light emission.

In each of the embodiments described above, regarding the constituent material of the hole injection layer, instead of PEDOT, a polypyrrole derivative, a polyaniline derivative, SPAN (sulfate ion-modified polyaniline), and a triphenylamine derivative are used in the same manner. When the light emitting elements were manufactured, the wettability of the film-forming ink on the hole injection layer was good.
In each of the embodiments described above, regarding the constituent material of the hole injection layer, a light emitting device was similarly manufactured using Nafion (registered trademark) instead of PSS. The wettability of the film-forming ink was good.
In each of the examples described above, regarding the constituent material of the hole injection layer, PSS was omitted and a light emitting element was manufactured in the same manner. The wettability was good.

  DESCRIPTION OF SYMBOLS 1 ... Light emitting element 1B ... Light emitting element 1G ... Light emitting element 1R ... Light emitting element 2 ... Substrate 3 ... Anode 4 ... Hole injection layer 5 ... Hole transport layer 6 ... Red light emitting layer 7A ... 1st intermediate layer 7B 2nd intermediate layer 8 Blue light emitting layer 9 Green light emitting layer 10 Electron transport layer 11 Electron injection layer 12 Cathode 13 Sealing member 15 Laminated body 19B Color filter 19G Color filter 19R Color filter 20 Substrate 21 Substrate 22 Planarization layer 24 Driving transistor 27 Conductive portion 31 Bulkhead 32 Reflective film 33 ... Corrosion prevention film 34 ... Cathode cover 35 ... Epoxy layer 36 ... Shading layer 100 ... Display device 100R, 100G, 100B ... Subpixel 101 ... Light emitting device 110 ... Head 111 ... Head body 112 ... Diaphragm 113 ... Piezo element 114 ... Body 115 ... Nozzle plate 115P ... Ink discharge surface 116 ... Reservoir 117 ... Ink chamber 118 ... Nozzle 130 ... Base 140 ... Table 170 ... Table positioning means 171 ... First moving means 172 ... Motor 180 ... Head positioning means 181 ... Second moving means 182 ... Linear motor 183 ... Motor 184 ... Motor 185 ... Motor 190 ... Control device 191 ... Drive circuit 200 ... Droplet discharge device 241 ... Semiconductor layer 242 ... Gate insulating layer 243 ... Gate electrode 244 ... Source electrode 245 ... Drain electrode 300 ... Ink for film formation 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main unit 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation buttons 1204 ... Earpiece 1206 ... Mouthpiece 1300 ... Digital still camera 1302 ... Case 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Circuit board 1312 ... Video signal output terminal 1314 ... Input / output terminal 1430 ... Television monitor 1440 ... Personal computer

Claims (14)

A film-forming material;
A liquid medium for dissolving or dispersing the film-forming material,
The film-forming ink, wherein the liquid medium includes an ether compound having a surface tension of 35 dyn / cm ² or less and represented by the following formula (I).

[In the above formula (I), R ₁ and R ₂ are each a linear alkyl group, branched alkyl group or cyclic alkyl group having 1 to 4 carbon atoms. R ₃ is an alkylene group having 1 to 3 carbon atoms. N is an integer of 0 or more and 4 or less. When n is 2 or more, R ₃ may be the same as or different from each other. ]   2. The film-forming ink according to claim 1, wherein n is 2 or more and 4 or less in the formula (I). The ink for film formation according to claim 2, wherein in the formula (I), R ₃ has 2 or 3 carbon atoms.   4. The film-forming ink according to claim 1, wherein the content of the ether compound in the liquid medium is 0.1% to 100 wt%.   The film-forming ink according to claim 1, wherein the liquid medium contains an aromatic hydrocarbon compound in addition to the ether compound.   The film-forming ink according to any one of claims 1 to 5, wherein the film-forming material is soluble in a non-aqueous solvent.   The film-forming ink according to claim 6, wherein the film-forming material is a material constituting a hole transport layer or a light-emitting layer of an organic electroluminescence element or a precursor thereof.   8. The film-forming ink according to claim 1, wherein the ink is used for forming a film composed of the film-forming material as a main material by being applied to a substrate and removing the liquid medium.   The film-forming ink according to claim 1, which is used for film formation by a droplet discharge method. Applying the film-forming ink according to claim 1 onto a substrate;
And removing the liquid medium from the film-forming ink to form a film. Applying the film-forming ink according to claim 1 onto a substrate;
And removing the liquid medium from the film-forming ink to form a hole transport layer or a light-emitting layer.   A light emitting device manufactured using the method for manufacturing a light emitting device according to claim 11.   A light-emitting device comprising the light-emitting element according to claim 12.   An electronic apparatus comprising the light emitting device according to claim 13.

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