JP2013222507A - Light emitting element, display device and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a light emitting element having excellent light emitting characteristics and life characteristics and emitting blue light; a display device including the light emitting element and excellent in reliability; and an electronic apparatus.SOLUTION: A light emitting element 1B includes: a cathode 8; an anode 3B comprising a metal oxide as a main material; a blue light emitting functional layer 5B disposed between the anode 3B and the cathode 8 and having a function of blue light emission; and a carrier selection layer 46 in which a hole transport layer 43, a first hole injection layer 44, and a first electron injection layer 61 are laminated in order from a side of the blue light emitting functional layer 5B between the blue light emitting functional layer 5B and the anode 3B. The carrier selection layer 46 is disposed so as to be brought into contact with the anode 3B on a side of the first electron injection layer 61.

Description

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

In the manufacture of organic electroluminescence elements (so-called organic EL elements), a red light emitting layer and a green light emitting layer included in an organic EL element that emits light of each color are formed by a coating method, and a blue light emitting layer is formed by a vacuum deposition method (vapor deposition method). A formed display device has been proposed (see, for example, Patent Document 1).
This is because an organic EL device manufactured using a coating method such as an inkjet method is an organic EL device that emits red and green light, and has a practical light emission life (luminance life) and light emission efficiency (current efficiency or external quantum). However, organic EL elements that emit blue light often do not reach a practical light emission lifetime or luminous efficiency, and organic EL elements that emit blue light that are produced using a vacuum deposition method are: It is a technique that focuses on the fact that its light emission lifetime is several times longer than that produced using a coating method and often reaches a practical level. In other words, even when a light emitting organic EL device manufactured using a liquid phase process such as an ink jet method does not reach a practical light emission lifetime or light emission efficiency, a vapor phase process such as a vacuum evaporation method is used. The organic EL element having the same luminescent color produced in this way may have a light emission life and light emission efficiency of a practical level.

  In such a display device, a red organic EL element (red pixel) and a green organic EL element (green pixel) are respectively formed on a red light emitting layer and a green light emitting layer of the blue light emitting layer using a vacuum deposition method. In other words, the blue light emitting layer is formed on the entire surface including the red light emitting layer and the green light emitting layer by a vacuum deposition method. Therefore, the manufacturing method of the display device having such a configuration does not need to selectively deposit (deposit) a blue light emitting layer only on the blue organic EL element (blue pixel) using a high-definition mask. It is most suitable for manufacture of a display device provided with.

  Here, when such a manufacturing method of a display device is used, the blue organic EL element (blue pixel) has a hole transport layer and a hole injection layer located on the anode side of the blue light emitting layer applied by a coating method (liquid phase). The hole transport layer is in contact with the blue light emitting layer. In this case, there is a problem that the light emission characteristics and life characteristics of the blue organic EL element are deteriorated as compared with the case where the hole transport layer is formed by using a vapor deposition method (vapor phase process).

JP 2007-73532 A

  An object of the present invention is to provide a light-emitting element that emits blue light having excellent light emission characteristics and lifetime characteristics, and a display device and an electronic apparatus that are provided with the light-emitting element and have excellent reliability.

Such an object is achieved by the present invention described below.
The light emitting device of the present invention comprises a cathode,
An anode composed mainly of a metal oxide,
A blue light emitting functional layer having a function of emitting blue light provided between the anode and the cathode;
Between the blue light emitting functional layer and the anode, from the blue light emitting layer functional layer side, there is a carrier selection layer in which a hole transport layer, a hole injection layer, and an electron injection layer are laminated in this order. ,
The carrier selection layer is provided on the electron injection layer side so as to be in contact with the anode.
Accordingly, it is possible to improve the light emission efficiency of the light emitting element that emits blue light, and to extend the lifetime.

In the light emitting device of the present invention, the electron injection layer is preferably composed of a metal-based material as a main material.
As a result, the electron injection layer can be formed using a vapor phase process. In addition, when the electron injection layer is composed of a metal material as the main material, the diffusion of the metal material to the hole transport layer side can be suppressed or prevented more accurately.

In the light emitting device of the present invention, the metal oxide is preferably ITO.
Thereby, when the electron injection layer is composed of a metal-based material as a main material, the diffusion of the metal-based material toward the hole transport layer can be suppressed or prevented more accurately.
In the light emitting device of the present invention, it is preferable that the blue light emitting functional layer and the carrier selection layer are formed using a gas phase process.
A light-emitting element including a blue light-emitting functional layer and a carrier selection layer formed through a gas phase process has sufficient light emission lifetime characteristics at a practical level.

In the light emitting device of the present invention, it is preferable that the carrier selection layer exhibits a function of hindering electrons from escaping from the cathode side to the anode side.
Thereby, blue light can be emitted by the blue light emitting functional layer.
The display device of the present invention includes the light emitting element of the present invention.
Thereby, a highly reliable display device can be obtained.

A display device of the present invention includes the light emitting element of the present invention and a long wavelength light emitting element that emits light having a longer wavelength than blue,
The long-wavelength light emitting device has the cathode, the blue light emitting functional layer, the carrier selection layer, and the anode,
Furthermore, it has a long wavelength light emission functional layer having a function of emitting light having a wavelength longer than that of blue provided between the carrier selection layer and the anode.
Accordingly, a highly reliable display device including a light emitting element that emits blue light and a long wavelength light emitting element that emits light having a longer wavelength than blue light can be obtained.

In the display device of the present invention, in the long wavelength light emitting element, by applying a voltage between the anode and the cathode, light emission of the blue light emitting functional layer is significantly suppressed, and the long wavelength light emitting function is achieved. It is preferred that the layer emits light selectively or predominantly.
Thereby, since the purity of the emission color of the long wavelength light emitting functional layer is improved, the light emission efficiency can be improved and the life of the long wavelength light emitting element can be extended.

In the display device of the present invention, the long wavelength light emitting functional layer is preferably a red light emitting functional layer having a function of emitting red light.
Thus, the display device of the present invention is suitably applied to a display device including a long wavelength light emitting element having a red light emitting functional layer having a function of emitting red light.
In the display device of the present invention, the long wavelength light emitting functional layer is preferably a green light emitting functional layer having a function of emitting green light.
Thus, the display device of the present invention is suitably applied to a display device including a long wavelength light emitting element having a green light emitting functional layer having a function of emitting green light.

In the display device according to the aspect of the invention, in the long wavelength light emitting element, the carrier selection layer preferably exhibits a function of allowing electrons to escape from the cathode side to the anode side.
Accordingly, light having a longer wavelength than blue can be emitted by the long wavelength light emitting functional layer.
An electronic apparatus according to the present invention includes the display device according to the present invention.
Thereby, an electronic device with high reliability can be obtained.

It is a longitudinal cross-sectional view which shows embodiment of the display apparatus to which the display apparatus of this invention is applied. 1 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which an electronic apparatus of the present invention is applied. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) to which the electronic device of this invention is applied. It is a perspective view which shows the structure of the digital still camera to which the electronic device of this invention is applied. 1 is a longitudinal sectional view schematically showing a display device of Example 1. FIG. 6 is a longitudinal sectional view schematically showing a display device of Comparative Example 1. FIG. It is the longitudinal cross-sectional view which showed the display apparatus of the comparative example 2 typically. 10 is a longitudinal sectional view schematically showing a display device of Comparative Example 3. FIG. It is the longitudinal cross-sectional view which showed the display apparatus of the comparative example 4R typically. It is the longitudinal cross-sectional view which showed the display apparatus of the comparative example 4G typically. It is the longitudinal cross-sectional view which showed the display apparatus of the comparative example 4B typically.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a light-emitting element, a display device, and an electronic device according to the invention will be described with reference to the accompanying drawings. Note that the light emission efficiency in this embodiment, this example, and this comparative example refers to current efficiency or external quantum efficiency.
(Display device)
First, prior to describing the light emitting element of the present invention, the display device of the present invention will be described.

Hereinafter, a case where the display device of the present invention is applied to a display device will be described as an example.
FIG. 1 is a longitudinal sectional view showing an embodiment of a display device to which the display device of the present invention is applied.
The display device 100 shown in FIG. 1 drives the substrate 21, a plurality of light emitting elements 1R, 1G, and 1B provided corresponding to the sub-pixels 100R, 100G, and 100B, and the light emitting elements 1R, 1G, and 1B, respectively. And a plurality of driving transistors 24.

In the present embodiment, the display device 100 includes a bottom emission structure display that transmits the light R, G, and B from the substrate 21 side when the light emitting elements 1R, 1G, and 1B emit light R, G, and B, respectively. It is a panel.
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 a semiconductor material such as silicon, a gate insulating layer 242 formed on the semiconductor layer 241, a gate electrode 243 formed on the gate insulating layer 242, and a source electrode 244. And a drain electrode 245.
On the planarizing layer 22, light emitting elements (organic EL elements) 1 R, 1 G, and 1 B are provided corresponding to the driving transistors 24.

The light emitting elements 1R, 1G, and 1B are arranged in order of the first layer, the second layer, and the third layer from the cathode 8 side between the anodes 3R, 3G, and 3B and the cathode 8, respectively. Prepare.
The first layer is a layer having a function of emitting the first color. Hereinafter, a layer having a function of emitting a certain color is referred to as a light emitting functional layer. In the present embodiment, the first color is blue, and the first layer is the blue light emitting functional layer 5B.

  The second layer is a carrier selection layer 46. The carrier selection layer is a layer having a function of selecting a carrier flow by the function of the third layer. Hereinafter, a layer having a function of selecting a carrier flow by the function of the third layer is referred to. This is referred to as a carrier selection layer. In this embodiment, the carrier selection layer 46 includes a first electron injection layer (electron injection layer) 61, a first hole injection layer (hole injection layer) 44, and a hole transport layer 43, which are anodes (3R, 3G). 3B) It is comprised by the laminated body laminated | stacked in this order from the side.

In the light emitting elements 1R and 1G, the third layer is a layer having a function of emitting the second color, and is a red light emitting functional layer 5R and a green light emitting functional layer 5G, respectively. That is, the second color in the present embodiment is red and green in the light emitting elements 1R and 1G, respectively.
In the light emitting element 1B, the third layer is the anode 3B.
The light emitting element 1R includes an anode 3R, a second hole injection layer 41R, an intermediate layer 42R, a red light emitting functional layer 5R as a third layer, and a carrier as a second layer on the planarizing layer 22. The selection layer 46, the blue light emitting functional layer 5B as the first layer, the electron transport layer 62, the second electron injection layer 63, and the cathode 8 are laminated in this order.

Further, the light emitting element 1G includes an anode 3G, a second hole injection layer 41G, an intermediate layer 42G, a green light emitting functional layer 5G as a third layer, and a second layer on the planarizing layer 22. The carrier selection layer 46, the blue light emitting functional layer 5B as the first layer, the electron transport layer 62, the second electron injection layer 63, and the cathode 8 are laminated in this order.
Furthermore, the light emitting element 1B includes an anode 3B as a third layer, a carrier selection layer 46 as a second layer, a blue light emitting functional layer 5B as a first layer, and an electron on the planarizing layer 22. The transport layer 62, the second electron injection layer 63, and the cathode 8 are stacked in this order.

A partition wall 31 is provided between adjacent ones of the light emitting elements 1R, 1G, and 1B having such a configuration, whereby the light emitting elements 1R, 1G, and 1B are individually provided.
In this embodiment, in each light emitting element 1R, 1G, 1B, each anode 3R, 3G, 3B, each second hole injection layer 41R, 41G, each intermediate layer 42R, 42G, and each light emitting functional layer 5R, 5G, The first electron injection layer 61, the first hole injection layer 44, the hole transport layer 43, the blue light emitting functional layer 5B, the electron transport layer 62, and the second electron injection layer are provided separately by being partitioned by the partition walls 31. 63 and the cathode 8 are provided integrally. With this configuration, the anodes 3R, 3G, and 3B of the light emitting elements 1R, 1G, and 1B constitute pixel electrodes (individual electrodes), and the cathodes 8 of the light emitting elements 1R, 1G, and 1B are A common electrode is formed. The anodes 3R, 3G, and 3B of the light emitting elements 1R, 1G, and 1B are electrically connected to the drain electrodes 245 of the driving transistors 24 by conductive portions (wirings) 27.

As described above, in the display device 100 including the light emitting elements 1R, 1G, and 1B, the light emission luminance of each of the light emitting elements 1R, 1G, and 1B is controlled by using the driving transistor 24, that is, each of the light emitting elements 1R, 1G. By controlling the voltage applied to 1B, the display device 100 can perform full color display.
The light-emitting elements of the present invention are applied to the light-emitting elements 1R, 1G, and 1B having such a configuration. Details of the light-emitting elements 1R, 1G, and 1B will be described later.

Further, in the present embodiment, 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.
The sealing substrate 20 is provided on the epoxy layer 35 so as to cover it. Thereby, since the airtightness of the light emitting elements 1R, 1G, and 1B is secured and the intrusion of oxygen and moisture can be prevented, the reliability of the light emitting elements 1R, 1G, and 1B can be improved.
The display device 100 as described above can display a single color by simultaneously emitting light from each of the light emitting elements 1R, 1G, and 1B, and can also display full color by emitting light by combining the light emitting elements 1R, 1G, and 1B. It becomes.
In the display device 100 having such a configuration, the light emitting element of the present invention and the display device of the present invention are applied. Hereinafter, the light emitting elements 1R, 1G, and 1B included in the display apparatus 100 will be sequentially described.

(Light emitting element 1R)
The light emitting element (long wavelength light emitting element) 1R includes a second hole injection layer 41R, an intermediate layer 42R, a red light emitting functional layer 5R, a carrier selecting layer 46, a blue light emitting functional layer 5B, and an electron transporting layer 62. In addition, a laminate in which the second electron injection layer 63 is laminated in this order from the anode 3R side is interposed between the anode 3R and the cathode 8.

  In the light emitting element (red light emitting element) 1R, the carrier selection layer 46 is a stacked body in which a first electron injection layer 61, a first hole injection layer 44, and a hole transport layer 43 are stacked in this order from the anode 3R side. And is provided on the first electron injection layer 61 side so as to be in contact with the red light emitting functional layer 5R. In the light emitting element 1R, the anode 3R and the cathode 8 constitute an individual electrode and a common electrode, respectively, the anode 3R functions as an electrode for injecting holes into the second hole injection layer 41R, and the cathode 8 is the first electrode. It functions as an electrode for injecting electrons into the electron transport layer 62 through the two-electron injection layer 63.

Hereinafter, each part which comprises the light emitting element 1R is demonstrated sequentially.
[Anode 3R]
The anode 3R is an electrode that injects holes into the second hole injection layer 41R.
The constituent material of the anode 3R is not particularly limited, but a material having a large work function and excellent conductivity is preferably used.

As a constituent material of the anode 3R, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₂ O ₃ , SnO ₂ , fluorine-added SnO ₂ , Sb-added SnO ₂ , ZnO, Al-added ZnO, and Ga-added are used. Examples thereof include metal oxides such as ZnO, Au, Pt, Ag, Cu, and alloys containing these, and one or more of these can be used in combination.

The average thickness of the anode 3R is not particularly limited, but is preferably about 10 nm to 200 nm, and more preferably about 30 nm to 150 nm.
Note that when the display device 100 is a bottom emission structure display panel, the anode 3R is required to have light transmittance, and therefore, among the above-described constituent materials, a metal oxide having light transmittance is preferably used.

[Second hole injection layer 41R]
The second hole injection layer 41R has a function of facilitating hole injection from the anode 3R.
The constituent material (hole injection material) of the second hole injection layer 41R is not particularly limited, but can be formed by using a liquid phase process in the step of forming the second hole injection layer 41R described later. In addition, an ion conductive hole injection material in which an electron accepting dopant is added to a conductive polymer material (or a conductive oligomer material) is preferably used.

  Examples of such ion conductive hole injection materials include polythiophonic hole injection materials such as poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonic acid) (PEDOT / PSS), polyaniline, and the like. -Polyaniline-based hole injection material such as poly (styrenesulfonic acid) (PANI / PSS), oligoaniline derivatives represented by the following general formula (1), and electron-accepting dopants represented by the following general formula (4) And an oligoaniline-based hole injection material formed by forming a salt.

［式中、Ｒ^１、Ｒ^２およびＲ^３は、それぞれ独立して未置換もしくは置換の一価炭化水素基またはオルガノオキシ基を示し、ＡおよびＢは、それぞれ独立して下記一般式（２）または下記一般式（３）で表される二価の基であり、Ｒ^４〜Ｒ^１１、はそれぞれ独立して水素原子、水酸基、未置換もしくは置換の一価炭化水素基またはオルガノオキシ基、アシル基、またはスルホン酸基であり、ｍおよびｎは、それぞれ独立して１以上の正数で、ｍ＋ｎ≦２０を満足する。］

[Wherein R ¹ , R ² and R ³ each independently represents an unsubstituted or substituted monovalent hydrocarbon group or an organooxy group, and A and B each independently represent the following general formula (2) Or a divalent group represented by the following general formula (3), wherein R ^{4 to} R ¹¹ are each independently a hydrogen atom, a hydroxyl group, an unsubstituted or substituted monovalent hydrocarbon group, an organooxy group, or an acyl. Each of m and n is independently a positive number of 1 or more and satisfies m + n ≦ 20. ]

［式中、Ｄは、ベンゼン環、ナフタレン環、アトラセン環、フェナントレン環または複素環を表し、Ｒ^１２、Ｒ^１３は、それぞれ独立してカルボキシル基またはヒドロキシル基を表す。］

[Wherein, D represents a benzene ring, a naphthalene ring, an atracene ring, a phenanthrene ring or a heterocyclic ring, and R ¹² and R ¹³ each independently represent a carboxyl group or a hydroxyl group. ]

The average thickness of the second hole injection layer is not particularly limited, but is preferably about 5 nm or more and 150 nm or less, and more preferably about 10 nm or more and 100 nm or less.
The second hole injection layer 41R can be omitted depending on the combination of the types of constituent materials and film thicknesses of the anode 3R, the intermediate layer 42R, and the red light emitting functional layer 5R constituting the light emitting element 1R. .

[Intermediate layer 42R]
The intermediate layer 42R has a function of transporting holes injected from the second hole injection layer 41R to the red light emitting functional layer 5R. The intermediate layer 42R may have a function of blocking electrons that are about to pass from the red light emitting functional layer 5R to the intermediate layer 42R.
The constituent material of the intermediate layer 42R is not particularly limited. For example, the trilayer represented by the following general formula (5) can be formed using a liquid phase process in the formation step of the intermediate layer 42R described later. An amine compound such as a phenylamine polymer is preferably used.

The average thickness of the intermediate layer 42R is not particularly limited, but is preferably about 5 nm to 100 nm, more preferably about 10 nm to 50 nm.
The intermediate layer 42R includes the anode 3R, the second hole injection layer 41R, the red light emission functional layer 5R, the first electron injection layer 61, the hole transport layer 43, and the blue light emission functional layer 5B that constitute the light emitting element 1R. Depending on the combination of the types of constituent materials of the electron transport layer 62, the second electron injection layer 63, and the cathode 8, the thickness thereof, and the like, they can be omitted.

[Red light emitting functional layer 5R]
The red light emitting functional layer (long wavelength light emitting functional layer) 5R includes a red light emitting material that emits red light.
In the light emitting element 1R, the red light emitting functional layer 5R constitutes a third layer provided between the anode 3R and the carrier selection layer (second layer) 46, and the red light emitting functional layer 5R is the light emitting element. It has a function of emitting the second color (red) in 1R. That is, it has a function of emitting light having a longer wavelength than blue.

  The constituent material of the red light emitting functional layer 5R is not particularly limited. However, in the step of forming the red light emitting functional layer 5R, which will be described later, the red light emitting functional layer 5R can be formed into a solution or dispersion so that it can be formed using a liquid phase process. desirable. Therefore, as the constituent material of the red light emitting functional layer 5R, a polymer red light emitting material and a low molecular red light emitting material that can be dissolved or dispersed in a solvent or a dispersion medium are preferably used. 6) and a polymeric red light-emitting material represented by the following general formula (7).

In addition, the light emitting element 1R including the red light emitting functional layer 5R formed through such a liquid phase process sufficiently has a light emission lifetime characteristic of a practical level.
The average thickness of the red light emitting functional layer 5R is not particularly limited, but is preferably about 10 nm or more and 150 nm or less, and more preferably about 20 nm or more and 100 nm or less.

[Carrier selection layer 46]
A carrier selection layer (second layer) 46 is configured by a stacked body in which the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 are stacked in this order from the anode 3R side. .
In the light emitting element 1R, the carrier selection layer 46 performs a carrier injection operation of smoothly injecting electrons flowing from the blue light emission functional layer 5B to the carrier selection layer 46 into the red light emission functional layer 5R. That is, it exhibits the function of allowing electrons to escape from the cathode 8 side to the anode 3R side. For this reason, in the light emitting element 1R, the light emission of the blue light emitting functional layer 5B is greatly suppressed, and the red light emitting functional layer 5R selectively or predominantly emits light.

[First Electron Injection Layer 61]
The first electron injection layer 61 is one of the layers constituting the carrier selection layer 46 and is in contact with the red light emitting functional layer 5R.
Examples of the constituent material of the first electron injection layer 61 include alkali metals, alkaline earth metals, rare earth metals, alkali metal salts (oxides, fluorides, chlorides, etc.), alkaline earth metal salts (oxides, Fluorides, chlorides, etc.), rare earth metal salts (oxides, fluorides, chlorides, etc.), electron injection materials (metal materials) such as metal complexes, etc., one or two of these A combination of the above can be used.

By configuring the first electron injection layer 61 using such an electron injection material as a main material, electrons are injected from the blue light emitting functional layer 5B to the red light emitting functional layer 5R via the carrier selection layer 46. Efficiency can be further improved.
Examples of the alkali metal include Li, Na, K, Rb, and Cs. Examples of the alkaline earth metal include Mg, Ca, Sr, and Ba. Furthermore, examples of the rare earth metal include Nd, Sm, Y, Tb, and Eu.

Examples of the alkali metal salt include LiF, Li ₂ CO ₃ , LiCl, NaF, Na ₂ CO ₃ , NaCl, CsF, Cs ₂ CO ₃ , and CsCl. Examples of the alkaline earth metal salt include CaF ₂ , CaCO ₃ , SrF ₂ , SrCO ₃ , BaF ₂ , and BaCO ₃ . Furthermore, examples of the rare earth metal salt include SmF ₃ and ErF ₃ .

Examples of the metal complex include organometallic complexes having 8-quinolinol or a derivative thereof such as 8-quinolinolatolithium (Liq) or tris (8-quinolinolato) aluminum (Alq ₃ ) as a ligand.
Moreover, the formation process of the first electron injection layer 61 may use a vapor phase process such as a vacuum evaporation method (evaporation method) or a sputtering method, or a liquid phase process such as an ink jet method or a slit coat method. May be.

Furthermore, the first electron injection layer 61 may be formed in a form in which two or more types of electron injection layers are stacked. Thereby, the carrier injection operation in the light emitting element 1R of the carrier selection layer 46 is accurately performed.
The average thickness of the first electron injection layer 61 is not particularly limited, but is preferably about 0.01 nm or more and 10 nm or less, and more preferably about 0.1 nm or more and 5 nm or less. By setting the average thickness of the first electron injection layer 61 within this range, the carrier injection operation in the light emitting element 1R of the carrier selection layer 46 is accurately performed.

[First hole injection layer 44]
The first hole injection layer 44 is one of the layers constituting the carrier selection layer 46 and is located between the first electron injection layer 61 and the hole transport layer 43 and is in contact with both of them. is there.
The constituent material of the first hole injection layer 44 is not particularly limited, but can be formed by using a vapor phase process such as a vacuum evaporation method in the step of forming the hole transport layer 43 described later. For example, copper phthalocyanine, 4,4 ′, 4 ″ -tris (N, N-phenyl-3-methylphenylamino) triphenylamine (m-MTDATA), and a compound represented by the following formula (8) Examples include amine compounds such as benzidine derivatives, HAT-CN represented by the following formula (9), and the like, and one or more of them can be used in combination.

  The average thickness of the first hole injection layer 44 is not particularly limited, but is preferably about 0.01 nm or more and 10 nm or less, and more preferably about 0.1 nm or more and 5 nm or less. By setting the average thickness of the first hole injection layer 44 within such a range, the carrier injection operation in the light emitting element 1R of the carrier selection layer 46 is accurately performed.

[Hole transport layer 43]
The hole transport layer 43 is one of the layers constituting the carrier selection layer 46, and is a layer in contact with the blue light emitting functional layer 5B.
The constituent material of the hole transport layer 43 is not particularly limited, but may be formed by using a vapor phase process such as a vacuum deposition method in the formation step of the hole transport layer 43 described later, for example, N, N′-diphenyl-N, N′-di (m-tolyl) -benzidine (TPD), bis [N- (1-naphthyl) -N-phenyl] benzidine represented by the following formula (10) (α- NPD) and amine compounds such as benzidine derivatives such as the compound represented by the following formula (11) can be used, and one or more of them can be used in combination.

  The average thickness of the hole transport layer 43 is not particularly limited, but is preferably about 1 nm or more and 50 nm or less, and more preferably about 5 nm or more and 30 nm or less. By setting the average thickness of the hole transport layer 43 within such a range, the carrier injection operation in the light emitting element 1R of the carrier selection layer 46 is accurately performed.

[Blue light emitting functional layer 5B]
The blue light emitting functional layer 5B includes a blue light emitting material that emits blue light.
In the present embodiment, this blue light emitting functional layer 5B constitutes a first layer provided between the anode (3R, 3G, 3B) and the cathode 8, and this blue light emitting functional layer 5B is the first color. (Blue) emits light.
The constituent material of the blue light emitting functional layer 5B is not particularly limited, but a material that can be formed by using a vapor phase process is suitably used in the step of forming the blue light emitting functional layer 5B, which will be described later. And a blue light emitting material of a styryl derivative represented by (12).

  In addition, as a constituent material of the blue light emitting functional layer 5B, a material in which a host material is doped with a blue light emitting material as a guest material is used. The host material has a function of recombining holes and electrons to generate excitons and transferring the energy of the excitons to the blue light-emitting material (Felster transfer or Dexter transfer). Due to the function of the host material, the blue light-emitting material that is the guest material is efficiently excited and emits light.

  Here, examples of the host material include anthracene derivatives represented by the following formula (13), the following formula (14), and the following formula (15), and one or more of these are used in combination. You can also. Moreover, as a blue luminescent material as a guest material, the styryl derivative represented by following formula (16), following formula (17), and following formula (18) is mentioned, for example, Of these, 1 type or 2 types or more Can also be used in combination.

Note that the light-emitting element 1B including the blue light-emitting functional layer 5B formed through such a gas phase process has sufficient light emission lifetime characteristics at a practical level.
Further, when such a guest material and host material are used, the content (dope amount) of the guest material in the blue light emitting functional layer 5B is about 0.1% or more and 20% or less by weight with respect to the host material. It is preferable that it is about 0.5% or more and 10% or less. Luminous efficiency can be optimized by setting the content of the guest material in such a range.
The average thickness of the blue light emitting functional layer 5B is not particularly limited, but is preferably about 5 nm or more and 100 nm or less, and more preferably about 10 nm or more and 50 nm or less.

[Electron transport layer 62]
The electron transport layer 62 has a function of transporting electrons injected from the cathode 8 through the second electron injection layer 63 to the electron transport layer 62 to the blue light emitting functional layer 5B. In addition, the electron transport layer 62 may have a function of blocking holes that try to pass from the blue light emitting functional layer 5 </ b> B to the electron transport layer 62.

Although it does not specifically limit as a constituent material (electron transport material) of the electron carrying layer 62, In the formation process of the electron carrying layer 62 mentioned later, in order to form using a gaseous-phase process, for example, tris (8- Quinoline derivatives such as organometallic complexes having 8-quinolinol or its derivatives as ligands, such as quinolinolato) aluminum (Alq ₃ ) and 8-quinolinolatolithium (Liq), 2- (4-tert-butylphenyl)- Oxides such as 5- (4-biphenyl) -1,3,4-oxadiazole (tBu-PBD), 2,5-bis (1-naphthyl) -1,3,4-oxadiazole (BND) Triazoles such as diazole derivatives, 3- (4-biphenyl) -4-phenyl-5- (4-tert-butylphenyl) -1,2,4-triazole (TAZ) Preferred examples of such compounds include pyrrole derivatives, silole derivatives such as compounds represented by the following formula (19), pyridine derivatives, pyrimidine derivatives, quinoxaline derivatives, and nitrogen-containing heterocyclic derivatives such as compounds represented by the following formula (20). Of these, one or two or more of these can be used in combination.

The average thickness of the electron transport layer 62 is not particularly limited, but is preferably about 1 nm or more and 100 nm or less, and more preferably about 5 nm or more and 50 nm or less. Thereby, the electrons injected from the second electron injection layer 63 can be suitably transported to the blue light emitting functional layer 5B.
The electron transport layer 62 includes the red light emitting functional layer 5R, the first electron injecting layer 61, the hole transporting layer 43, the blue light emitting functional layer 5B, the second electron injecting layer 63, and the cathode 8 constituting the light emitting element 1R. It may be omitted depending on the combination of the type of the constituent material and its film thickness.

[Second Electron Injection Layer 63]
The second electron injection layer 63 has a function of improving the efficiency of electron injection from the cathode 8 to the electron transport layer 62.
The constituent material (electron injection material) of the second electron injection layer 63 is not particularly limited. For example, the same materials as those described as the constituent material of the first electron injection layer 61 described above can be used.

The constituent materials (electron injecting materials) of the second electron injecting layer 63 and the first electron injecting layer 61 can obtain optimum injection efficiency in accordance with the combination of constituent materials of the two layers that hold them. Since the material is selected, the constituent material of the second electron injection layer 63 and the constituent material of the first electron injection layer 61 may be the same or different.
The average thickness of the second electron injection layer 63 is not particularly limited, but is preferably about 0.01 nm or more and 100 nm or less, and more preferably about 0.1 nm or more and 10 nm or less.
The second electron injection layer 63 can be omitted depending on the combination of the types of constituent materials of the electron transport layer 62 and the cathode 8 and the film thickness thereof.

[Cathode 8]
The cathode 8 is an electrode that injects electrons into the electron transport layer 62 via the second electron injection layer 63.
As a constituent material of the cathode 8, a material having a small work function is preferably used. As a constituent material of the cathode 8, for example, Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc can be formed by using a vapor phase process in the step of forming the cathode 8 described later. , Y, Yb, Ag, Cu, Al, Cs, Rb, Au, or an alloy containing these is used, and one or more of these are used in combination (for example, a multi-layer laminate). be able to.

  In particular, in the case of the bottom emission structure display device 100 as in the present embodiment, the cathode 8 is not required to transmit light, and examples of the constituent material of the cathode 8 include Al, Ag, AlAg, and AlNd. Such metals or alloys are preferably used. By using such a metal or alloy as a constituent material of the cathode 8, the electron injection efficiency and stability of the cathode 8 can be improved.

  The average thickness of the cathode 8 is not particularly limited, but is preferably about 50 nm or more and 1000 nm or less, and more preferably about 100 nm or more and 500 nm or less.

  When the display device 100 is a display device having a top emission structure, it is preferable to use a metal or an alloy such as MgAg, MgAl, MgAu, AlAg as a constituent material of the cathode 8. By using such a metal or alloy as a constituent material of the cathode 8, it is possible to improve the electron injection efficiency and stability of the cathode 8 while maintaining the light transmittance of the cathode 8.

The average thickness of the cathode 8 is not particularly limited, but is preferably about 1 nm or more and 50 nm or less, and more preferably about 5 nm or more and 20 nm or less.
In addition, the anode 3R, the second hole injection layer 41R, the intermediate layer 42R, the red light emitting functional layer 5R, the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 of the light emitting element 1R having such a configuration. Between the blue light emitting functional layer 5B, the electron transport layer 62, the second electron injection layer 63, and the cathode 8, an arbitrary layer may be provided.

(Light emitting element 1G)
The light emitting element (long wavelength light emitting element) 1G includes a second hole injection layer 41G, an intermediate layer 42G, a green light emitting functional layer 5G, a carrier selection layer 46, a blue light emitting functional layer 5B, and an electron transporting layer 62. In addition, a stacked body in which the second electron injection layer 63 is stacked in this order from the anode 3G side is interposed between the anode 3G and the cathode 8.

In the light emitting element (green light emitting element) 1G, the carrier selection layer 46 is a stacked body in which a first electron injection layer 61, a first hole injection layer 44, and a hole transport layer 43 are stacked in this order from the anode 3G side. And is provided on the first electron injection layer 61 side so as to be in contact with the green light emitting functional layer 5B. In the light emitting device 1G, the anode 3G and the cathode 8 constitute an individual electrode and a common electrode, respectively, the anode 3G functions as an electrode for injecting holes into the second hole injection layer 41G, and the cathode 8 is the first electrode. It functions as an electrode for injecting electrons into the electron transport layer 62 through the two-electron injection layer 63.
Hereinafter, the light-emitting element 1G will be described, but the description will focus on differences from the above-described light-emitting element 1R, and description of similar matters will be omitted.
The light emitting element 1G has the same configuration as the light emitting element 1R described above except that the green light emitting functional layer 5G is provided instead of the red light emitting functional layer 5R.

[Green light emitting functional layer 5G]
The green light emitting functional layer (long wavelength light emitting functional layer) 5G includes a green light emitting material that emits green light.
In the light emitting element 1G, the green light emitting functional layer 5G constitutes a third layer provided between the anode 3G and the carrier selection layer (second layer) 46, and the green light emitting functional layer 5G is a light emitting element. It has a function of emitting the second color (green) in 1G. That is, it has a function of emitting light having a longer wavelength than blue.

  The constituent material of the green light emitting functional layer 5G is not particularly limited. However, in the formation process of the green light emitting functional layer 5G, which will be described later, the green light emitting functional layer 5G can be formed into a solution or dispersion so that it can be formed using a liquid phase process. desirable. Therefore, as a constituent material of the green light emitting functional layer 5G, a high molecular weight green light emitting material and a low molecular weight green light emitting material that can be dissolved or dispersed in a solvent or a dispersion medium are preferably used. 21) and the polymeric green light-emitting material represented by the following general formula (22).

In addition, the light emitting element 1G including the green light emitting functional layer 5G formed through such a liquid phase process has sufficient light emission life characteristics at a practical level.
The average thickness of the green light emitting functional layer 5G is not particularly limited, but is preferably about 10 nm or more and 150 nm or less, and more preferably about 20 nm or more and 100 nm or less.
In addition, the anode 3G, the second hole injection layer 41G, the intermediate layer 42G, the green light emitting functional layer 5G, the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 of the light emitting element 1G having such a configuration. Between the blue light emitting functional layer 5B, the electron transport layer 62, the second electron injection layer 63, and the cathode 8, an arbitrary layer may be provided.

(Light emitting element 1B)
The light emitting element (blue light emitting element) 1B has a laminate in which a carrier selection layer 46, a blue light emitting functional layer 5B, an electron transport layer 62, and a second electron injection layer 63 are laminated in this order from the anode 3B side. In this case, it is inserted between the anode 3B and the cathode 8.
In the light emitting element 1B, the carrier selection layer 46 is configured by a stacked body in which the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 are stacked in this order from the anode 3B side. On the one-electron injection layer 61 side, it is provided in contact with the anode 3B. In the light emitting element 1B, the anode 3B and the cathode 8 constitute an individual electrode and a common electrode, respectively, the anode 3B functions as an electrode for injecting holes into the carrier selection layer 46, and the cathode 8 is used for second electron injection. It functions as an electrode for injecting electrons into the electron transport layer 62 through the layer 63.

Hereinafter, the light-emitting element 1B will be described, but the description will focus on differences from the light-emitting element 1R described above, and description of similar matters will be omitted.
The light emitting device 1B is the same as the light emitting device except that the second hole injection layer 41R, the intermediate layer 42R, and the red light emitting functional layer 5R are omitted, and the anode 3B and the carrier selection layer 46 are in contact with each other. The configuration is the same as 1R. However, due to the configuration in which the anode 3B and the carrier selection layer 46 are in contact with each other, the function of the carrier selection layer 46 in the light emitting element 1B is greatly different from the function of the carrier selection layer 46 in the light emitting elements 1R and 1G. . Further, the function required for the anode 3B is also different.

[Anode 3B]
The anode 3B is an electrode that injects holes into the carrier selection layer 46 (first electron injection layer 61).
In addition, in the anode 3B, in the light emitting element 1B, the carrier selection layer 46 reliably performs a carrier (electron) blocking operation that prevents (inhibits) carrier (electrons) from escaping from the blue light emitting functional layer 5B side to the anode 3B side. It has a function of adsorbing an electron injection material (metal material) constituting the first electron injection layer 61 so as to exhibit.
Among the materials described as the constituent material of the anode 3R of the light emitting element 1R, a metal oxide is used as the constituent material of the anode 3B so that the adsorptive ability can be exhibited accurately. In particular, ITO is preferably used. That is, metal oxide (especially ITO) adsorbs the electron injection material accurately due to its excellent affinity for the electron injection material.

[Carrier selection layer 46]
A carrier selection layer (second layer) 46 is constituted by a stacked body in which the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 are stacked in this order from the anode 3B side. . As materials constituting the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43, the first electron injection layer 61 and the first hole injection layer 44 of the light emitting element 1R described above, respectively. Further, the same material as the hole transport layer 43 can be used.

  In the light emitting element 1B, the carrier selection layer 46 performs a carrier block operation of blocking electrons flowing from the blue light emitting functional layer 5B to the carrier selecting layer 46 and retaining these electrons (carriers) in the blue light emitting functional layer 5B. For this reason, in the light emitting element 1B, the blue light emitting functional layer 5B emits light efficiently. In order to perform this carrier block operation accurately, it is desirable to use a layer having a carrier block function for the hole transport layer 43 of the light emitting element 1B. For example, by using the amine compound mentioned as the constituent material of the hole transport layer 43 of the light emitting element 1R, the hole transport layer 43 has an electron blocking function.

Note that the anode 3B, the second hole injection layer 41B, the first electron injection layer 61, the first hole injection layer 44, the hole transport layer 43, the blue light emitting functional layer 5B, and the electron transport layer of the light emitting element 1B having such a configuration. 62, an arbitrary layer may be provided between each of the second electron injection layer 63 and the cathode 8.
Here, for example, in a light emitting device having a structure in which a hole transport layer formed using a liquid phase process (coating method) is interposed between the blue light emitting functional layer 5B and the anode 3B, It has been found that the light emission characteristics and the life characteristics are deteriorated as compared with the case where is formed using a vapor phase process (evaporation method or the like).

On the other hand, like the light emitting element 1B, the laminate, that is, the hole transport layer 43, the second hole injection layer 44, and the first electron injection layer 61 are disposed between the blue light emitting layer 5B and the anode 3B. With the configuration in which the hole is interposed, the hole transport layer 43 can be formed using a vapor phase process.
Furthermore, by adopting a configuration in which the first electron injection layer 61 and the anode 3B are in contact, carriers (electrons) that prevent (inhibit) carriers (electrons) from escaping from the blue light emitting functional layer 5B side to the anode 3B side. ) The block operation can be surely exerted on the carrier selection layer 46.

  This is because, when a layer made of an organic material such as a hole transport layer is interposed between the anode 3B and the first electron injection layer 61, the constituent material contained in the first electron injection layer 61 is The carrier (electron) blocking operation tends to decrease due to diffusion toward the hole transport layer 43 side. On the other hand, in the present invention, since the first electron injection layer 61 and the anode 3B are in contact with each other, the anode 3B adsorbs the electron injection material (metal material) constituting the first electron injection layer 61. It is assumed that due to this, the diffusion of the constituent material to the hole transport layer 43 side is accurately suppressed or prevented.

  As a result, holes are smoothly supplied (injected) from the anode 3 side to the blue light emitting functional layer 5B, and electrons are supplied (injected) smoothly from the cathode 8 side. In the blue light emitting functional layer 5B, holes and electrons are recombined, and excitons (excitons) are generated by the energy released during the recombination, and energy (fluorescence or phosphorous) is generated when the excitons return to the ground state. Light), the blue light emitting layer 5B emits blue light.

Therefore, in the light emitting element 1B, since both holes and electrons can be smoothly supplied to the blue light emitting layer 5B, the blue light emitting efficiency of the light emitting element 1B is improved and the life of the light emitting element 1B is extended. It becomes possible to plan.
Hereinafter, the function and effect of the light emitting elements 1R, 1G, and 1B will be described focusing on the function of the carrier selection layer 46.

In the present embodiment, the carrier selection layer (second layer) 46 includes a first electron injection layer 61, a first hole injection layer 44, and a hole transport layer 43 in this order from the anode 3R, 3G, 3B side. It is comprised by the laminated body laminated | stacked.
The carrier selection layer 46 having such a configuration causes the amount of electrons injected from the blue light emitting functional layer 5B to the carrier selection layer 46 to be a layer (third layer) in contact with the anode 3R, 3G, 3B side of the carrier selection layer 46. Accordingly, the layer is selectively controlled. That is, the carrier selection layer (second layer) 46 is a layer having a function of selecting a carrier flow by the function of the third layer.

  Specifically, when the layers directly in contact with the anode 3R, 3G side of the carrier selection layer 46 are the red light emitting functional layer 5R and the green light emitting functional layer 5G, respectively, as in the light emitting elements 1R and 1G, that is, carrier selection When the light emitting functional layer having the function of emitting the second color is in contact with the anode side interface of the layer, the carrier selection layer 46 causes electrons flowing from the blue light emitting functional layer 5B to the carrier selection layer 46 to be emitted into the red light emitting functional layer 5R. Then, the green light emitting functional layer 5G is smoothly injected (carrier injection operation). For this reason, in the blue light emitting functional layer 5B of the light emitting element 1R, recombination of holes and electrons is accurately suppressed or prevented. Therefore, the blue light emitting functional layer 5B of the light emitting element 1R does not emit blue light or emits blue light. Even if it does, the light emission is suppressed exactly. In contrast, electrons are supplied (injected) from the cathode 8 side via the blue light emitting functional layer 5B to the red light emitting functional layer 5R, and holes are supplied (injected) from the anode 3R side. Then, in the red light emitting functional layer 5R, holes and electrons recombine, and excitons (excitons) are generated by this recombination, and energy is emitted as fluorescence or phosphorescence when the excitons return to the ground state. Therefore, the red light emitting functional layer 5R emits red light. As a result, the light emitting element 1R emits red light. Similarly, also in the light emitting element 1G, light emission of the blue light emitting functional layer 5B is greatly suppressed, and the green light emitting functional layer 5G selectively or predominantly emits light. As a result, the light emitting element 1G emits green light.

  On the other hand, when the layer in contact with the anode 3B side of the carrier selection layer 46 is the anode 3B as in the light emitting element 1B, that is, when the anode is in contact with the anode side interface of the carrier selection layer, the carrier selection layer 46 has a blue light emitting function. The electrons (carriers) flowing from the layer 5B to the carrier selection layer 46 are blocked, and these electrons are retained in the blue light emitting functional layer 5B (carrier blocking operation). For this reason, in the blue light emitting functional layer 5B, the holes supplied (injected) from the anode 3B side and the electrons supplied (injected) from the cathode 8 side easily recombine. This recombination generates excitons (excitons), and when the excitons return to the ground state, energy is emitted as fluorescence or phosphorescence. Therefore, the blue light emitting functional layer 5B emits light efficiently. As a result, the light emitting element 1B emits blue light with high efficiency.

Thus, the carrier selection layer 46 performs a carrier injection operation or a carrier block operation depending on the type of the third layer in contact with the carrier selection layer (second layer) 46.
The reason why the behavior of the carrier selection layer 46 in the light-emitting element 1R and the light-emitting element 1G with respect to electrons and the behavior of the carrier selection layer 46 in the light-emitting element 1B are different from each other will be described using an example in which the anode 3B is mainly made of ITO. Do.

  First, when the layers in contact with the anode (3R, 3G) side of the carrier selection layer 46, such as the light emitting elements 1R and 1G, are the red light emitting functional layer 5R and the green light emitting functional layer 5G, respectively, the light emitting elements 1R and 1G The electron injection materials constituting the first electron injection layer 61 in the carrier selection layer 46 are respectively the first hole injection layer 44 and the hole transport layer 43 (in particular, the hole transport layer) of the light emitting elements 1R and 1G. 43), and the electron blocking function of the light-emitting elements 1R and 1G, particularly the hole transport layer 43, is greatly reduced. As a result, in the light emitting elements 1R and 1G, electrons are smoothly injected from the blue light emitting functional layer 5B into the hole transport layer 43. Further, due to the function of the first electron injection layer 61 existing between the red light emitting functional layer 5R and the green light emitting functional layer 5G and the hole transporting layer 43, the red light emitting functional layer 5R and the green light emitting functional layer 5R are green. Electrons are smoothly injected into the light emitting functional layer 5G. From the above, when the layers in contact with the anode (3R, 3G) side of the carrier selection layer 46 are the red light emission functional layer 5R and the green light emission functional layer 5G, respectively, like the light emitting elements 1R and 1G, the carrier selection layer 46 is Electrons flowing from the blue light emitting functional layer 5B to the carrier selecting layer 46 are smoothly injected into the red light emitting functional layer 5R and the green light emitting functional layer 5G, respectively (carrier injection operation). That is, the carrier selection layer 46 performs an operation of smoothly flowing electrons (carriers) from the blue light emitting functional layer 5B to the red light emitting functional layer 5R and the green light emitting functional layer 5G.

  On the other hand, when the layer in contact with the anode 3B side of the carrier selection layer 46 is the anode 3B and the anode 3B is made of ITO as in the light emitting element 1B, the second layer in the carrier selection layer 46 of the light emitting element 1B is formed. The electron injection material (alkali metal or alkaline earth metal) constituting the one-electron injection layer 61 is adsorbed on the interface of the anode 3B. Therefore, the electron injection material constituting the first electron injection layer 61 of the light emitting element 1B does not diffuse into the first hole injection layer 44 and the hole transport layer 43 of the light emitting element 1B. The electron blocking function provided in the hole transport layer 43 does not deteriorate. As a result, in the light emitting element 1B, electrons flowing from the blue light emitting functional layer 5B to the hole transporting layer 43 are blocked by the hole transporting layer 43 and the first hole injecting layer 44, and are contained in the blue light emitting functional layer 5B. stay. As described above, when the layer in contact with the anode 3B side of the carrier selection layer 46 is the anode 3B, the carrier selection layer 46 blocks electrons flowing from the blue light emission functional layer 5B to the carrier selection layer 46, and these electrons are emitted by the blue light emission function. Fasten to layer 5B (carrier block operation). That is, the carrier selection layer 46 performs an operation of suppressing the flow of electrons (carriers) flowing from the blue light emitting functional layer 5B. As a result, the blue light emitting functional layer 5B emits blue light. The electron injecting material is adsorbed on the interface of the anode 3B because the electron injecting material (alkali metal, alkaline earth metal) and ITO are both inorganic materials, and the first holes made of organic materials. Compared to the injection layer 44, it is assumed that the electron injection material and ITO have a higher affinity. In addition, since the anode 3B made of ITO usually has a rough surface roughness Ra of about 0.1 nm to 5 nm, it is anchored at the interface between the anode 3B and the first electron injection layer 61. It is presumed that the effect is produced, and as a result, the adhesion strength of the first electron injection layer 61 to the anode 3B is improved.

  According to the study of the present inventor, the light emitting element 1R is excluded from the carrier selecting layer 46, and the blue light emitting functional layer 5B and the red light emitting functional layer 5R are in contact with each other to be stacked (excluding the carrier selecting layer). In the red light emitting element), when a voltage is applied between the anode 3R included in the red light emitting element excluding the carrier selection layer and the cathode 8, electrons injected from the cathode 8 side into the blue light emitting functional layer 5B are converted into a red light emitting function. It cannot be smoothly injected (supplied) into the layer 5R, and due to this, holes and electrons recombine in the blue light emitting functional layer 5B, so that the blue light emitting functional layer 5B emits blue light, It has been found that the red color purity of the red light emitting element excluding the carrier selection layer is deteriorated. In addition, in the red light emitting element excluding the carrier selection layer, the electrons injected from the cathode 8 side into the blue light emitting functional layer 5B cannot be smoothly injected (supplied) into the red light emitting functional layer 5R. It has been found that the carrier balance between electrons and holes in the light emitting functional layer 5R is lost and the light emission efficiency is lowered. Furthermore, in the red light emitting element excluding the carrier selection layer, red electrons cannot be smoothly injected (supplied) from the cathode 8 side into the blue light emitting functional layer 5B. It has been found that the energy barrier against carriers at the cathode side interface of the light emitting functional layer 5R increases and the drive voltage rises.

  As described above, the red light emitting element excluding the carrier selection layer has problems that the red color purity is deteriorated, the light emission efficiency is lowered, and the drive voltage is raised. However, when the carrier selection layer 46 is interposed between the blue light emitting functional layer 5B and the red light emitting functional layer 5R as in the light emitting element 1R, the light is injected into the blue light emitting functional layer 5B from the cathode 8 side. Since these electrons can be smoothly injected (supplied) into the red light emitting functional layer 5R without staying in the blue light emitting functional layer 5B, all these problems are solved.

  Similarly, in the case of the green light emitting element (the green light emitting element excluding the carrier selection layer) having a structure in which the blue light emitting functional layer 5B and the green light emitting functional layer 5G are laminated in contact with each other by removing the carrier selecting layer 46 from the light emitting element 1G, Electrons injected from the cathode 8 side into the blue light-emitting functional layer 5B cannot be smoothly injected (supplied) into the green light-emitting functional layer 5G. The problem of a decrease and an increase in drive voltage arises. However, when the carrier selection layer 46 is interposed between the blue light emitting functional layer 5B and the green light emitting functional layer 5G as in the light emitting element 1G, the light is injected into the blue light emitting functional layer 5B from the cathode 8 side. Since these electrons can be smoothly injected (supplied) into the green light emitting functional layer 5G without staying in the blue light emitting functional layer 5B, all these problems are solved.

  Further, the hole transport layer 43 and the blue light emitting functional layer 5B of the present embodiment can be formed using a vapor phase process. According to the study of the present inventors, in the light emitting device 1B, in the blue light emitting device having a configuration using a liquid phase process such as an ink jet method for forming at least one of the hole transport layer 43 and the blue light emitting functional layer 5B. As compared with the light emitting element 1B, it has been found that there is a problem that the light emission lifetime and the light emission efficiency are lowered.

  Contamination of at least one of the hole transport layer 43 and the blue light emitting functional layer 5B is considered to be one of the causes of this problem. That is, when the hole transport layer 43 and the blue light emitting functional layer 5B can be formed using a vapor phase process as in the light emitting element 1B, the cathode side interface of the hole transport layer 43 is set to an atmosphere other than vacuum. The next blue light emitting functional layer 5B can be continuously formed without exposing, but when a liquid phase process is used to form at least one of the hole transport layer 43 and the blue light emitting functional layer 5B. Since film formation by a liquid phase process is difficult to be performed in a vacuum atmosphere, film formation by a liquid phase process is performed in an atmosphere other than vacuum (for example, air or nitrogen), and at least the cathode of the hole transport layer 43 The 8-side interface is exposed to an atmosphere other than vacuum. Thus, when at least one of the hole transport layer 43 and the blue light emitting functional layer 5B is formed using a liquid phase process, the cathode 8 side interface of the hole transport layer 43 is likely to be contaminated. It is obvious. Further, when the hole transport layer 43 is formed by a liquid phase process, a solution in which a hole transport material is dissolved or dispersed in a solvent or a dispersion medium is used for film formation. A trace amount of solvent remains, which may contaminate the whole hole transport layer 43. Similarly, when the blue light emitting functional layer 5B is formed by a liquid phase process, a very small amount of solvent remains in the blue light emitting functional layer 5B, which may contaminate the entire blue light emitting functional layer 5B.

  On the other hand, when the hole transport layer 43 and the blue light-emitting functional layer 5B can be formed using a vapor phase process as in the light emitting device 1B, the hole transport layer 43 and Contamination of the hole transport layer 43 and the blue light-emitting functional layer 5B due to the formation of at least one of the blue light-emitting functional layers 5B can be avoided, and the hole transport layer 43 and the blue light-emitting functional layer 5B can be avoided by using a liquid phase process. All of the problems of the light emission lifetime and the reduction in light emission efficiency of the blue light emitting element due to the formation of at least one of the layers are solved.

  Further, in the light emitting device 1B of the present embodiment, unlike the light emitting devices 1R and 1G, the formation of the second hole injection layers 41R and 41G is omitted, and the carrier selection layer 46 and the blue light emitting function are formed on the anode 3B. The layer 5B, the electron transport layer 62, the second electron injection layer 63, and the cathode 8 are laminated in this order. Each layer formed on these anodes 3B can be formed by using a vapor phase process. Here, assuming that the second hole injection layer 41B is provided on the anode 3B, the second hole injection layer 41B is usually formed using a liquid phase process together with the second hole injection layers 41R and 41G. Then, it is exposed to the formation environment of the intermediate layers 42R and 42G and the light emitting functional layers 5R and 5G using the liquid phase process. As a result, there is a possibility that the entire second hole injection layer 41B may be contaminated, and as a result, the light emission lifetime and the light emission efficiency of the light emitting element 1B may be reduced. On the other hand, in the light emitting element 1B of the present embodiment, the formation of the second hole injection layer 41B is omitted, and all the layers formed on the anode 3B can be formed using a vapor phase process. Since contamination of each layer can be reliably prevented, all the problems of the light emission lifetime and the light emission efficiency of the blue light emitting element are solved.

  In the light emitting device 1B of the present embodiment, the average thickness of the first electron injection layer 61 is preferably set to about 0.01 nm to 10 nm, more preferably about 0.1 nm to 5 nm, It is formed with a thin film thickness. By setting such a film thickness, a tunnel effect in which holes (carriers) pass through the first electron injection layer 61 can be reliably obtained, and the efficiency of hole injection from the anode 3B to the first hole injection layer 44 is improved. Can be improved. Furthermore, in the light emitting device 1B of the present embodiment, the first hole injection layer 44 is provided between the hole transport layer 43 and the first electron injection layer 61, and thus passes through the first electron injection layer 61. The positive holes can be more reliably injected into the first hole injection layer 44.

  In the present embodiment, the anode 3B is preferably composed of ITO as a main material, and the first electron injection layer 61 is composed of an electron injection material of an alkali metal, an alkaline earth metal, or a compound thereof as a main material. Is preferred. In this case, in the light emitting element 1 </ b> B, when these electron injection materials included in the first electron injection layer 61 diffuse to the hole transport layer 43 side, holes due to the diffusion of the electron injection material to the hole transport layer 43. Deterioration of the electron blocking property of the transport layer 43 and concomitant reduction of the light emission efficiency in the blue light emitting functional layer 5B, and inhibition of light emission in the blue light emitting functional layer 5B due to diffusion of the electron injection material into the blue light emitting functional layer 5B The problem of reduced luminous efficiency occurs. However, in the present embodiment, in the light emitting element 1B, the first electron injection layer 61 and the anode 3B made of ITO as a main material are in contact with each other, so that the electron injection material is adsorbed on the interface of the anode 3B. Due to this, the diffusion of the electron injection material to the hole transport layer 43 side is accurately suppressed or prevented, and all the problems caused by the diffusion of the electron injection material to the hole transport layer 43 side are solved. The

(Method for Manufacturing Display Device 100)
The display device 100 as described above can be manufactured, for example, as follows.
[1] First, a substrate 21 is prepared, and a plurality of driving transistors 24 are formed so as to correspond to the subpixels 100R, 100G, and 100B to be formed, and then a planarization layer is formed so as to cover these driving transistors 24. 22 is formed (first step).

[1-A] First, the substrate 21 is prepared, and the driving transistor 24 is formed on the substrate 21.
[1-Aa] First, a semiconductor film composed mainly of amorphous silicon having an average thickness of about 30 nm to 70 nm is formed on the substrate 21 by, for example, a plasma CVD method.

[1-Ab] Next, the semiconductor film is crystallized by laser annealing, solid phase growth, or the like to change the amorphous silicon into polysilicon.
Here, in the laser annealing method, for example, a line beam with a beam length of 400 mm is used with an excimer laser, and the output intensity is set to about 200 mJ / cm ² , for example.
[1-Ac] Next, a semiconductor layer 241 is obtained by patterning the semiconductor film to form islands. For example, TEOS (tetraethoxysilane) or oxygen gas is used to cover these island-like semiconductor layers 241. As a source gas, a gate insulating layer 242 composed mainly of silicon oxide or silicon nitride having an average thickness of about 60 nm to 150 nm is formed by a plasma CVD method or the like.

[1-Ad] Next, a conductive film composed mainly of a metal such as aluminum, tantalum, molybdenum, titanium, or tungsten is formed on the gate insulating layer 242 by sputtering, for example, and then patterned. A gate electrode 243 is formed.
[1-Ae] Next, in this state, high-concentration phosphorus ions are implanted to form source / drain regions in a self-aligned manner with respect to the gate electrode 243. Note that a portion where no impurity is introduced becomes a channel region.

[1-B] Next, the source electrode 244 and the drain electrode 245 that are electrically connected to the driving transistor 24 are formed.
[1-Ba] First, a first planarization layer is formed so as to cover the gate electrode 243, and then a contact hole is formed.
[1-Bb] Next, the source electrode 244 and the drain electrode 245 are formed in the contact hole.

[1-C] Next, a wiring (relay electrode) 27 that electrically connects the drain electrode 245 and each of the anodes 3R, 3G, and 3B is formed.
[1-Ca] First, a second planarizing layer is formed on the first planarizing layer, and then a contact hole is formed.
[1-Cb] Next, the wiring 27 is formed in the contact hole.
In addition, the planarization layer 22 is comprised by the 1st planarization layer and the 2nd planarization layer which were formed in the [1-B] process and the [1-C] process.

[2] Next, anodes (individual electrodes) 3R, 3G, and 3B are formed on the planarizing layer 22 so as to correspond to the wirings 27 (second step).
The anodes 3R, 3G, and 3B can be obtained by forming a thin film composed mainly of the constituent materials of the anodes 3R, 3G, and 3B on the planarizing layer 22 and then patterning the thin film.

[3] Next, on the planarization layer 22, areas for forming the light emitting elements 1R, 1G, and 1B (subpixels 100R, 100G, and 100B) are defined so as to partition the anodes 3R, 3G, and 3B. A partition wall (bank) 31 is formed so as to be partitioned (third step).
The partition wall 31 is patterned using a photolithography method or the like so that the anodes 3R, 3G, and 3B are exposed after an insulating film is formed on the planarization layer 22 so as to cover the anodes 3R, 3G, and 3B. Or the like.

Here, the constituent material of the partition wall 31 is selected in consideration of heat resistance, liquid repellency, ink solvent resistance, adhesion to the planarizing layer 22 and the like.
Specifically, examples of the constituent material of the partition wall 31 include an organic material such as an acrylic resin, a polyimide resin, and an epoxy resin, and an inorganic material such as SiO ₂ .
Further, the shape of the opening of the partition wall 31 may be any shape other than a square, for example, a polygon such as a circle, an ellipse, or a hexagon.

In addition, when making the shape of opening of the partition 31 into a polygon, it is preferable that the corner | angular part is rounded. Thus, when the second hole injection layers 41R, 41G, 41B, the intermediate layers 42R, 42G, and the light emitting functional layers 5R, 5G are formed using a liquid material as described later, these liquid materials are separated from the partition walls. 31 can be reliably supplied to every corner of the space inside.
The height of the partition wall 31 is appropriately set according to the thickness of the light emitting elements 1R, 1G, and 1B, and is not particularly limited, but is preferably about 0.5 μm or more and 5 μm or less. By having such a height, the function as a partition (bank) is sufficiently exhibited.

When the second hole injection layers 41R, 41G, and 41B, the intermediate layers 42R and 42G, and the light emitting functional layers 5R and 5G are formed by an inkjet method, the substrate 21 on which the partition walls 31 are formed is subjected to plasma treatment. Is desirable. Specifically, the surface of the substrate 21 on which the partition walls 31 are formed is first plasma processed using O ₂ gas as a processing gas. As a result, the surfaces of the anodes 3R, 3G, and 3B and the surfaces of the partition walls 31 (including wall surfaces) are activated and become lyophilic. Next, plasma processing is performed using a fluorine-based gas such as CF ₄ as a processing gas. As a result, the fluorine-based gas reacts only on the surface of the partition wall 31 made of a photosensitive resin, which is an organic material, to make the liquid repellent. Thereby, the function of the partition wall 31 as a partition wall is more effectively exhibited.

  [4] Next, the second hole injection layer 41R, the intermediate layer 42R, and the red light emitting functional layer 5R are formed inside the partition wall 31 located in the region where the light emitting element 1R is to be formed. The second hole injection layer 41G, the intermediate layer 42G, and the green light emitting functional layer 5G are formed inside the partition wall 31 located in the region where the film is to be formed (fourth step). This fourth step will be described in detail below for each of the light emitting elements 1R and 1G.

[Light emitting element 1R]
The second hole injection layer 41R, the intermediate layer 42R, and the red light emitting functional layer 5R are formed in this order inside the partition wall 31 located in the region where the light emitting element 1R is to be formed. The process for forming each layer is a second hole injection layer 41R formation process, an intermediate layer 42R formation process, and a red light emitting functional layer 5R formation process, which will be described in detail below.

[Second Hole Injection Layer 41R Formation Step]
First, the second hole injection layer 41R is applied by an inkjet method. Specifically, the ink (liquid material) for forming the second hole injection layer 41R containing the hole injection material is ejected from the head of the inkjet printing apparatus and applied onto each anode 3R (application process).
Here, as a solvent (ink solvent) or a dispersion medium (ink dispersion medium) used for preparing the ink for forming the second hole injection layer, for example, nitric acid, sulfuric acid, ammonia, hydrogen peroxide, water, carbon disulfide , Various inorganic solvents such as carbon tetrachloride, ethylene carbonate, ketone solvents such as methyl ethyl ketone (MEK), acetone, diethyl ketone, methyl isobutyl ketone (MIBK), methyl isopropyl ketone (MIPK), cyclohexanone, methanol, ethanol, isopropanol , Ethylene glycol, diethylene glycol (DEG), alcohol solvents such as glycerin, diethyl ether, diisopropyl ether, 1,2-dimethoxyethane (DME), 1,4-dioxane, tetrahydrofuran (THF), tetrahydropyran (THP), Ether solvents such as nisol, diethylene glycol dimethyl ether (diglyme), diethylene glycol ethyl ether (carbitol), cellosolv solvents such as methyl cellosolve, ethyl cellosolve, phenyl cellosolve, aliphatic hydrocarbon solvents such as hexane, pentane, heptane, cyclohexane , Cycloaliphatic, tetralin and other alicyclic hydrocarbon solvents, toluene, xylene, benzene, trimethylbenzene, tetramethylbenzene and other aromatic hydrocarbon solvents, pyridine, pyrazine, furan, pyrrole, thiophene, methylpyrrolidone and other fragrances Group heterocyclic compounds, amide solvents such as N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMA), dichloromethane, chloroform, 1,2-dichloroe Halogen compound solvents such as ethylene, ester solvents such as ethyl acetate, methyl acetate, ethyl formate, sulfur compound solvents such as dimethyl sulfoxide (DMSO), sulfolane, nitrile solvents such as acetonitrile, propionitrile, acrylonitrile, formic acid , Various organic solvents such as organic acid solvents such as acetic acid, trichloroacetic acid and trifluoroacetic acid, or mixed solvents containing them.

The liquid material applied on the anode 3R has high fluidity (low viscosity) and tends to spread in the horizontal direction (surface direction). However, since the anode 3R is surrounded by the partition wall 31, a predetermined material is used. Spreading outside the region is prevented, and the contour shape of the second hole injection layer 41R is accurately defined.
Next, post-treatment is performed on the applied second hole injection layer 41R (post-treatment step). Specifically, the second hole injection layer forming ink (liquid material) applied on each anode 3R is dried to form the second hole injection layer 41R. By this drying, the solvent or the dispersion medium can be removed. Examples of the drying method include a method of leaving in a reduced pressure atmosphere, a method of heat treatment (for example, about 40 ° C. or more and about 80 ° C. or less), a method of a flow of an inert gas such as nitrogen gas, and the like. Further, if necessary, the substrate 21 on which the second hole injection layer 41R is formed is heated (baked) at about 100 ° C. or more and 300 ° C. or less. By this heating, the solvent or dispersion medium remaining in the film of the second hole injection layer 41R after drying can be removed. In addition, when a hole injection material that is crosslinked by heating and insolubilized in a solvent is used, the second hole injection layer 41R can be insolubilized by this heating. In addition, after this heating, the surface of the substrate 21 on which the second hole injection layer 41R is formed may be rinsed (washed) with a solvent in order to remove the insolubilized portion of the second hole injection layer 41R. This rinsing can prevent the insoluble portion of the second hole injection layer 41R from entering the intermediate layer 42R formed on the second hole injection layer 41R.

[Intermediate layer 42R forming step]
In the intermediate layer 42R forming step, first, the intermediate layer 42R is applied on each second hole injection layer 41R by the same ink jet method as the second hole injection layer 41R forming step, and then applied to the applied intermediate layer 42R. The post-process similar to the formation process of the second hole injection layer 41R is performed. However, the ink solvent or ink dispersion medium used for the ink for forming the intermediate layer 42R, the post-treatment method and conditions, and the like are appropriately selected from those suitable for forming the intermediate layer 42R.

[Red light emitting functional layer 5R forming step]
In the red light emitting functional layer 5R forming step, first, the red light emitting functional layer 5R is applied on each intermediate layer 42R by the ink jet method similar to the second hole injection layer 41R forming step, and then applied to the applied red light emitting functional layer 5R. On the other hand, a post-process similar to the second hole injection layer 41R formation step is performed. However, the ink solvent or ink dispersion medium used for the ink for forming the red light emitting functional layer 5R, the post-treatment method and conditions, and the like are appropriately selected from those suitable for forming the red light emitting functional layer 5R.

  It is preferable to use an ink jet method for the second hole injection layer 41R forming step, the intermediate layer 42R forming step, and the red light emitting functional layer 5R forming step. In the ink jet method, the amount of ink discharged and the landing position of ink droplets can be controlled with high accuracy regardless of the size of the area of the substrate. By using such a method, the second hole injection layer 41R can be made thin, It is possible to reduce the size and further increase the area of the display device 100. Further, since ink (liquid material) for forming each layer can be selectively supplied to the inside of the partition wall 31, ink waste can be omitted. However, the second hole injection layer 41R formation process, the intermediate layer 42R formation process, and the red light emitting functional layer 5R formation process are not limited to the ink jet method, but include, for example, sputtering, vacuum deposition, CVD, etc. Phase process, spin coating method (pyrosol method), casting method, micro gravure coating method, gravure coating method, bar coating method, roll coating method, wire bar coating method, dip coating method, spray coating method, screen printing method, flexographic method Liquid phase processes such as printing and offset printing can also be used.

[Light emitting element 1G]
The second hole injection layer 41G, the intermediate layer 42G, and the green light emitting functional layer 5G are formed in this order in the same manner as the light emitting element 1R inside the partition wall 31 located in the region where the light emitting element 1G is to be formed. . However, in each of the second hole injection layer 41G, the intermediate layer 42G, and the green light emitting functional layer 5G, the ink solvent or ink dispersion medium used for the ink for forming the layer, the post-treatment method and conditions, etc. A material suitable for forming each layer is appropriately selected.
As described above, when the second hole injection layers 41R and 41G, the intermediate layers 42R and 42G, and the light emitting functional layers 5R and 5G are formed by the ink jet method, the layers are completely formed through the coating process and the post-processing process. However, the coating process of each layer may be performed simultaneously with the coating process of other layers, and the post-processing process of each layer may be performed simultaneously with the post-processing process of other layers.

[5] Next, the red light emitting functional layer 5R, the green light emitting functional layer 5G, the anode 3B, and the partition wall 31 are overlapped, that is, the entire surface of the partition wall 31 opposite to the surface in contact with the planarization layer 22 is covered. Then, the first electron injection layer 61 is formed (fifth step).
As a result, the first electron injection layer 61 common to the light emitting elements 1R, 1G, and 1B is collectively formed (integrated).

  The first electron injection layer 61 can also be formed by the vapor phase process or the liquid phase process described in the above-mentioned step [light emitting element 1R]. Among these, it is preferable to use the vapor phase process. By using the vapor phase process, the first electron injection layer 61 is securely formed while preventing the layer dissolution between the red light emission functional layer 5R, the green light emission functional layer 5G, the anode 3B, and the first electron injection layer 61. Can be formed.

[6] Next, the first hole injection layer 44 is formed so as to cover the entire surface of the first electron injection layer 61 (sixth step). Thereby, the 1st positive hole injection layer 44 common to each light emitting element 1R, 1G, 1B is formed in a lump.
[7] Next, the hole transport layer 43 is formed so as to cover the entire surface of the first hole injection layer 44 (seventh step). Thereby, the hole transport layer 43 common to the light emitting elements 1R, 1G, and 1B is collectively formed.

[8] Next, the blue light emitting functional layer 5B is formed so as to cover the entire surface of the hole transport layer 43 (eighth step). Thereby, the blue light emission functional layer 5B common to each light emitting element 1R, 1G, 1B is formed in a lump.
[9] Next, the electron transport layer 62 is formed so as to cover the entire surface of the blue light emitting functional layer 5B (ninth step). Thereby, the electron transport layer 62 common to each light emitting element 1R, 1G, 1B is formed in a lump.

[10] Next, the second electron injection layer 63 is formed so as to cover the entire surface of the electron transport layer 62 (tenth step). As a result, the second electron injection layer 63 common to the light emitting elements 1R, 1G, and 1B is collectively formed.
[11] Next, the cathode 8 is formed so as to cover the entire surface of the second electron injection layer 63 (eleventh step). Thereby, the cathode 8 common to each light emitting element 1R, 1G, 1B is formed in a lump.

Each layer formed in the steps [6] to [11] can also be formed by the gas phase process or liquid phase process described in the step [light emitting element 1R]. Is preferred. By using a gas phase process, it is possible to reliably form a layer to be formed while preventing layer dissolution between adjacent layers.
Further, in the steps [Light emitting element 1R] and [Light emitting element 1G], the light emitting functional layers 5R and 5G are formed by using a liquid layer process such as an ink jet method, so that the light emitting functional layers having different emission colors are obtained. It is possible to easily paint 5R and 5G and to easily increase the area of the display device 100. In addition, in the steps [6] to [8], the hole transport layer 43, the first hole injection layer 44, and the blue light emitting functional layer 5B are formed by using a vapor phase process (vapor phase film formation method), respectively. As a result, the light emitting element 1B has a sufficient light emitting lifetime of a practical level. Furthermore, since the blue light emitting functional layer 5B common to the respective light emitting elements 1R, 1G, and 1B is formed collectively (integrally), it is selective to the light emitting element 1B using a high-definition mask. In addition, since it is not necessary to form the blue light emitting functional layer 5B, it is possible to simplify the process and further increase the area of the display device 100.

In the steps [5] to [7], the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 that are common to the respective light emitting elements 1R, 1G, and 1B are collectively formed. The high-definition mask has a structure in which the carrier selection layer 46 including the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 is integrally formed. Since it is not necessary to form the first electron injection layer 61, the first hole injection layer 44, and the hole transport layer 43 selectively with respect to the light emitting element 1B, the process can be simplified, and further the display The area of the device 100 can be easily increased.
As described above, a plurality of light emitting elements 1R, 1G, and 1B that respectively emit light in red, green, and blue are formed corresponding to the driving transistor 24.

[12] Next, the sealing substrate 20 is prepared, and an epoxy adhesive is interposed between the cathode 8 and the sealing substrate 20, and then the adhesive is dried.
Thereby, the cathode 8 and the sealing substrate 20 can be bonded via the epoxy layer 35 so as to cover the cathode 8 with the sealing substrate 20.
The sealing substrate 20 exhibits a function as a protective substrate that protects the light emitting elements 1R, 1G, and 1B. By providing such a sealing substrate 20 on the cathode 8, it is possible to more suitably prevent or reduce the light emitting elements 1R, 1G, and 1B from coming into contact with oxygen and moisture. The effects of improving the reliability of 1B and preventing deterioration and deterioration can be obtained more reliably.

Through the steps as described above, the display device (display device of the present invention) 100 in which the light emitting elements 1R, 1G, and 1B are sealed with the sealing substrate 20 is completed.
Such a display device 100 (the display device of the present invention) can be incorporated into various electronic devices.
FIG. 2 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.

In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.
In the personal computer 1100, the display unit included in the display unit 1106 is configured by the display device 100 described above.

FIG. 3 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. 4 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 input / output terminal 1314 for data communication as necessary. Further, the imaging signal stored in the memory of the circuit board 1308 is output to the television monitor 1430 or the personal computer 1440 by a predetermined operation.

The electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, in addition to the personal computer (mobile personal computer) in FIG. 2, the mobile phone in FIG. 3, and the digital still camera in FIG. Monitor direct-view video tape recorder, laptop personal computer, car navigation system, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and automatic ticket vending machines for financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiographs, ultrasound diagnostic devices, internal Endoscope display device), fish finder, various measuring instruments, Vessels such (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.
The light emitting element, the display device, and the electronic device of the present invention have been described based on the illustrated embodiments, but the present invention is not limited to these.

  For example, in the above-described embodiment, the display device includes a red light emitting element and a green light emitting element as light emitting elements that emit light having a wavelength longer than that of blue. A light emitting element that emits light having a longer wavelength than blue, such as an orange light emitting element, may be provided. In this case, the light emitting element of the present invention is applied to the yellow light emitting element and the orange light emitting element.

Next, specific examples of the present invention will be described.
In addition, this example and a comparative example are related to a display device with a large area, and a red light emitting element and a green light emitting element are formed by an ink-jet method, and a blue light emitting element is formed by a vacuum deposition method that does not require separate coating with a high-definition mask. To form. First, Example 1 is a specific implementation result of the above-described embodiment of the present invention. Next, Comparative Example 1 is the most common structure that can be considered when a red light emitting element and a green light emitting element are formed by an inkjet method, and a blue light emitting element is formed by a vacuum vapor deposition method that does not require separate coating with a high-definition mask. Indicates. Further, Comparative Example 2 has a structure intended to improve the characteristics of the red light emitting element and the green light emitting element, which have poor characteristics in Comparative Example 1. In addition, Comparative Example 3 has a structure that is intended to improve the characteristics of the blue light-emitting element, which has poor characteristics in Comparative Example 1.

1. Production of display device (light emitting device) and light emitting element (Example 1)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 321. Next, an ITO film having an average thickness of 50 nm is formed on the substrate 321 by sputtering, and then patterned by using a photolithography method to form ITO electrodes (anodes 303R, 303G, 303B / individual). Electrode).
Then, the substrate 321 on which the anodes 303R, 303G, and 303B were formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, after an insulating layer made of an acrylic resin is formed by spin coating on the substrate 321 on which the anodes 303R, 303G, and 303B are formed, the insulating layer is formed using a photolithography method. A partition wall (bank) was formed by patterning so as to expose the ITO electrode. Further, the surface of the substrate 321 provided with the partition walls is first subjected to plasma processing using O ₂ gas as a processing gas. As a result, the surfaces of the anodes 303R, 303G, and 303B and the surfaces of the partition walls (including the wall surfaces) are activated and become lyophilic. Subsequently, the surface of the substrate 321 on which the partition walls are formed is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

<3A> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the red light emitting element 301R was to be formed, using an inkjet method.
<3B> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the green light emitting element 301G was to be formed, using an inkjet method.
<3C> Next, after drying the PEDOT / PSS aqueous dispersion applied in each step of 3A and 3B, the substrate 321 is heated in the atmosphere, and each of the anodes 303R and 303G is subjected to PEDOT / PSS. The formed ion conductive second hole injection layers 341R and 341G having an average thickness of 50 nm were formed.

<4A> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the red light emitting element 301R is to be formed, using an inkjet method. did.
<4B> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the green light emitting element 301G is to be formed, using an inkjet method. did.

  <4C> Next, after drying the tetramethylbenzene solution of the compound represented by the general formula (5) applied in each step of 4A and 4B, the substrate 321 was heated in a nitrogen atmosphere. Further, the regions of the substrate 321 where the red light emitting element 301R and the green light emitting element 301G were to be formed were rinsed with xylene. As a result, intermediate layers 342R and 342G having an average thickness of 20 nm made of the compound represented by the general formula (5) were formed on the second hole injection layers 341R and 341G, respectively.

<5A> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (6) is applied to the inside of the partition located in the region where the red light emitting element 301R is to be formed, using an inkjet method. did.
<5B> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (21) is applied to the inside of the partition located in the region where the green light emitting element 301G is to be formed using the inkjet method. did.

  <5C> Next, a tetramethylbenzene solution of a compound represented by the above general formula (6) and a tetramethylbenzene solution of a compound represented by the above general formula (21) applied in each step of 5A and 5B After drying, the substrate 321 is heated in a nitrogen atmosphere. Thus, on each of the intermediate layers 342R and 342G, the red light emitting functional layer 305R having an average thickness of 60 nm composed of the compound represented by the general formula (6) and the compound represented by the general formula (21), respectively. And a green light emitting functional layer 305G having an average thickness of 60 nm.

<6> Next, a red light emitting functional layer 305R, a green light emitting function, which are located in a region where the red light emitting element 301R is to be formed, a region where the green light emitting element 301G is to be formed, and a region where the blue light emitting element 301B is to be formed, respectively. On the layer 305G and the anode 303B, a vapor deposition film containing Cs with an average thickness of 1.0 nm formed by vacuum vapor deposition using Cs ₂ CO ₃ as a vapor deposition source was formed as the first electron injection layer 361.

  Here, the “thin film” containing Cs means that it is a thin film containing at least Cs, which is a metal material constituting the Cs salt, and the metal-containing layer contains a metal salt that is a vapor deposition material. You can leave. The inventor has observed the following phenomenon in a preliminary experiment separately conducted, and indirectly that the vacuum-deposited film is not a film made of only Cs salt but a film containing Cs alone. I'm sure.

Specifically, it is confirmed that when an Al film deposited on a deposition film formed using Cs ₂ CO ₃ as a deposition source is exposed to the atmosphere, the Al surface violently fires and noticeable irregularities occur on the surface. It was done. If Cs ₂ CO ₃ is formed as a deposited film, no significant change should occur in the laminated Al film. This is presumably because the vapor deposited film contains Cs alone, and the Cs single part suddenly oxidized or absorbed by exposure to the atmosphere.

<7> Next, on the first electron injection layer 361, the first hole injection layer 344 having an average thickness of 5 nm composed of the compound represented by the above formula (8) was formed by using a vacuum deposition method. .
<8> Next, on the first hole injection layer 344, a hole transport layer 343 having an average thickness of 10 nm made of α-NPD was formed by vacuum deposition.
<9> Next, on the hole transport layer 343, a blue light-emitting functional layer 305B having an average thickness of 20 nm composed of the constituent materials of the blue light-emitting functional layer described below was formed by vacuum evaporation.
Here, as a constituent material of the blue light emitting functional layer 305B, a compound represented by the above formula (11) was used as a host material, and a compound represented by the above formula (14) was used as a guest material. The content (dope concentration) of the guest material (dopant) in the blue light emitting functional layer was 5.0% by weight with respect to the host material.

<10> Next, an electron transport layer 362 having an average thickness of 20 nm made of tris (8-quinolinolato) aluminum (Alq ₃ ) was formed on the blue light-emitting functional layer 305B by vacuum deposition.
<11> Next, a second electron injection layer 363 having an average thickness of 1.0 nm and made of lithium fluoride (LiF) was formed on the electron transport layer 362 by vacuum evaporation.

<12> Next, a cathode 308 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 363 using a vacuum deposition method.
<13> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a display device having a bottom emission structure as shown in FIG. 5 was manufactured.

(Comparative Example 1)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 421. Next, an ITO film having an average thickness of 50 nm is formed on the substrate 421 by sputtering, and then patterned by using a photolithography method to form ITO electrodes (anodes 403R, 403G, 403B / individually). Electrode).
Then, the substrate 421 on which the anodes 403R, 403G, and 403B were formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, after an insulating layer made of an acrylic resin is formed by spin coating on the substrate 421 on which the anodes 403R, 403G, and 403B are formed, the insulating layer is formed using a photolithography method. A partition wall was formed by patterning so as to expose the ITO electrode. Further, the surface of the substrate 421 on which the partition walls are formed is first plasma-treated using O ₂ gas as a processing gas. As a result, the surfaces of the anodes 403R, 403G, and 403B and the surfaces of the partition walls (including the wall surfaces) are activated and become lyophilic. Subsequently, the surface of the substrate 421 on which the partition walls are formed is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

<3A> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the red light emitting element 401R was to be formed, using an inkjet method.
<3B> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the green light emitting element 401G was to be formed, using an inkjet method.
<3C> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the blue light emitting element 401B was to be formed, using an inkjet method.
<3D> Next, after drying the PEDOT / PSS aqueous dispersion applied in each step of 3A, 3B, and 3C, the substrate 421 is heated in the air, and the anodes 403R, 403G, and 403B are respectively Ion conductive second hole injection layers 441R, 441G, and 441B having an average thickness of 50 nm made of PEDOT / PSS were formed.

<4A> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the red light emitting element 401R is to be formed using the inkjet method. did.
<4B> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the green light emitting element 401G is to be formed, using an inkjet method. did.

  <4C> Next, after drying the tetramethylbenzene solution of the compound represented by the general formula (5) applied in each step of 4A and 4B, the substrate 421 was heated in a nitrogen atmosphere. Further, the region of the substrate 421 where the red light emitting element 401R and the green light emitting element 401G were to be formed was rinsed with xylene. As a result, intermediate layers 442R and 442G having an average thickness of 10 nm made of the compound represented by the general formula (5) were formed on the second hole injection layers 441R and 441G, respectively.

<5A> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (6) is applied to the inside of the partition located in the region where the red light emitting element 401R is to be formed, using an inkjet method. did.
<5B> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (21) is applied to the inside of the partition located in the region where the green light emitting element 401G is to be formed using the inkjet method. did.

<5C> Next, a 1.0 wt% tetralin solution of α-NPD was applied to the inside of the partition located in the region where the blue light emitting element 401B was to be formed, using an inkjet method.
<5D> Next, a tetramethylbenzene solution of the compound represented by the above general formula (6) and a tetramethylbenzene solution of the compound represented by the above general formula (21) applied in each step of 5A, 5B and 5C. After drying the tetralin solution of α-NPD, the substrate 421 is heated in a nitrogen atmosphere. Thus, on each of the intermediate layers 442R and 442G, a red light emitting functional layer 405R having an average thickness of 60 nm composed of the compound represented by the general formula (6) and the compound represented by the general formula (21), respectively. And a green light emitting functional layer 405G having an average thickness of 60 nm. Further, a hole transport layer 443B having an average thickness of 10 nm made of α-NPD was formed on the second hole injection layer 441B.

  <6> Next, a red light emitting functional layer 405R, a green light emitting function, which are located in a region where the red light emitting element 401R is to be formed, a region where the green light emitting element 401G is to be formed, and a region where the blue light emitting element 401B is to be formed, respectively. On the layer 405G and the hole transport layer 443B, a blue light-emitting functional layer 405B having an average thickness of 20 nm and made of the following constituent materials was formed by vacuum deposition.

  Here, as a constituent material of the blue light emitting functional layer 405B, a compound represented by the above formula (13) was used as a host material, and a compound represented by the above formula (16) was used as a guest material. In addition, the content (dope concentration) of the guest material (dopant) in the blue light emitting functional layer 405B was 5.0% by weight with respect to the host material.

<7> Next, an electron transport layer 462 having an average thickness of 20 nm formed of the compound represented by the general formula (19) was formed on the blue light-emitting functional layer 405B by using a vacuum deposition method.
<8> Next, a second electron injection layer 463 having an average thickness of 0.5 nm and made of lithium fluoride (LiF) was formed on the electron transport layer 462 using a vacuum evaporation method.
<9> Next, a cathode 408 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 463 using a vacuum deposition method.

<10> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, the formation of the first electron injection layer 361 is omitted with respect to Example 1, and the hole transport layer 443B is formed instead of the hole transport layer 343, as shown in FIG. A display device with a bottom emission structure was manufactured.

(Comparative Example 2)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 521. Next, an ITO film having an average thickness of 50 nm is formed on the substrate 521 by sputtering, and then patterned by using a photolithography method to form ITO electrodes (anodes 503R, 503G, 503B / individually). Electrode).
Then, the substrate 521 provided with the anodes 503R, 503G, and 503B was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, after an insulating layer made of an acrylic resin is formed by spin coating on the substrate 521 on which the anodes 503R, 503G, and 503B are formed, the insulating layer is formed using a photolithography method. A partition wall was formed by patterning so as to expose the ITO electrode. Further, the surface of the substrate 521 provided with the partition walls is first subjected to plasma treatment using O ₂ gas as a processing gas. As a result, the surfaces of the anodes 503R, 503G, and 503B and the surfaces of the partition walls (including the wall surfaces) are activated and become lyophilic. Subsequently, the surface of the substrate 521 provided with the partition walls is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

<3A> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the red light emitting element 501R was to be formed, using an inkjet method.
<3B> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the green light emitting element 501G was to be formed, using an inkjet method.
<3C> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the blue light emitting element 501B was to be formed, using an inkjet method.
<3D> Next, after drying the PEDOT / PSS aqueous dispersion applied in each step of 3A, 3B, and 3C, the substrate 521 is heated in the atmosphere, and the anodes 503R, 503G, and 503B are respectively Ion conductive second hole injection layers 541R, 541G, and 541B made of PEDOT / PSS and having an average thickness of 50 nm were formed.

<4A> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the red light emitting element 501R is to be formed, using an inkjet method. did.
<4B> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the green light emitting element 501G is to be formed using the inkjet method. did.

  <4C> Next, after drying the tetramethylbenzene solution of the compound represented by the general formula (5) applied in each step of 4A and 4B, the substrate 521 was heated in a nitrogen atmosphere. Further, the regions of the substrate 521 where the red light emitting element 501R and the green light emitting element 501G are to be formed were rinsed with xylene. As a result, intermediate layers 542R and 542G having an average thickness of 10 nm made of the compound represented by the general formula (5) were formed on the second hole injection layers 541R and 541G, respectively.

<5A> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (6) is applied to the inside of the partition located in the region where the red light emitting element 501R is to be formed, using an inkjet method. did.
<5B> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (21) is applied to the inside of the partition located in the region where the green light emitting element 501G is to be formed using the inkjet method. did.

<5C> Next, a 1.0 wt% tetralin solution of α-NPD was applied to the inside of the partition located in the region where the blue light emitting element 501B was to be formed, using an inkjet method.
<5D> Next, a tetramethylbenzene solution of the compound represented by the above general formula (6) and a tetramethylbenzene solution of the compound represented by the above general formula (21) applied in each step of 5A, 5B and 5C. After drying the tetralin solution of α-NPD, the substrate 521 is heated in a nitrogen atmosphere. Thereby, on each of the intermediate layers 542R and 542G, a red light emitting functional layer 505R having an average thickness of 60 nm composed of the compound represented by the general formula (6) and the compound represented by the general formula (21), respectively. And a green light emitting functional layer 505G having an average thickness of 60 nm. Further, a hole transport layer 543B having an average thickness of 10 nm made of α-NPD was formed on the second hole injection layer 541B.

<6> Next, a red light emitting functional layer 505R, a green light emitting function, which are located in a region where the red light emitting element 501R is to be formed, a region where the green light emitting element 501G is to be formed, and a region where the blue light emitting element 501B is to be formed, respectively. On the layer 505G and the hole transport layer 543B, a vapor deposition film containing Cs having an average thickness of 1.0 nm formed by a vacuum vapor deposition method using Cs ₂ CO ₃ as a vapor deposition source was formed as a first electron injection layer 561. .

<7> Next, on the 1st electron injection layer 561, the blue light emission functional layer 505B with an average thickness of 20 nm comprised with the structural material shown below was formed using the vacuum evaporation method.
Here, as a constituent material of the blue light emitting functional layer 505B, a compound represented by the above formula (13) was used as a host material, and a compound represented by the above formula (16) was used as a guest material. Further, the content (dope concentration) of the guest material (dopant) in the blue light emitting functional layer 505B was 5.0% by weight with respect to the host material.

<8> Next, an electron transport layer 562 having an average thickness of 20 nm made of tris (8-quinolinolato) aluminum (Alq ₃ ) was formed on the blue light-emitting functional layer 505B by using a vacuum evaporation method.
<9> Next, on the electron transport layer 562, a second electron injection layer 563 having an average thickness of 1.0 nm made of lithium fluoride (LiF) was formed by vacuum evaporation.

<10> Next, a cathode 508 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 563 using a vacuum deposition method.
<11> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a bottom emission structure display device as shown in FIG. 7 in which the hole transport layer 543B was formed instead of the hole transport layer 343 with respect to Example 1 was manufactured.

(Comparative Example 3)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 621. Next, an ITO film having an average thickness of 50 nm is formed on the substrate 621 by sputtering, and then patterned by using a photolithography method to form ITO electrodes (anodes 603R, 603G, 603B / individually). Electrode).
Then, the substrate 621 on which the anodes 603R, 603G, and 603B were formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, after an insulating layer made of an acrylic resin is formed by spin coating on the substrate 621 on which the anodes 603R, 603G, and 603B are formed, the insulating layer is formed using a photolithography method. A partition wall was formed by patterning so as to expose the ITO electrode. Further, the surface of the substrate 621 on which the partition walls are formed is first plasma processed using O ₂ gas as a processing gas. As a result, the surfaces of the anodes 603R, 603G, and 603B and the surfaces of the partition walls (including the wall surfaces) are activated and become lyophilic. Subsequently, the surface of the substrate 621 on which the partition walls are formed is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

<3A> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the red light emitting element 601R was to be formed, using an inkjet method.
<3B> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the green light emitting element 601G was to be formed, using an inkjet method.
<3C> Next, after drying the PEDOT / PSS aqueous dispersion applied in each step of 3A and 3B, the substrate 621 is heated in the air, and each of the anodes 603R and 603G is subjected to PEDOT / PSS. The formed ion conductive second hole injection layers 641R and 641G having an average thickness of 50 nm were formed.

<4A> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the red light emitting element 601R is to be formed, using an inkjet method. did.
<4B> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the green light emitting element 601G is to be formed, using an inkjet method. did.

  <4C> Next, after drying the tetramethylbenzene solution of the compound represented by the general formula (5) applied in each step of 4A and 4B, the substrate 621 was heated in a nitrogen atmosphere. Further, regions of the substrate 621 where the red light emitting element 601R and the green light emitting element 601G are to be formed were rinsed with xylene. As a result, intermediate layers 642R and 642G having an average thickness of 10 nm made of the compound represented by the general formula (5) were formed on the second hole injection layers 641R and 641G, respectively.

<5A> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (6) is applied to the inside of the partition located in the region where the red light emitting element 601R is to be formed, using an inkjet method. did.
<5B> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (21) is applied to the inside of the partition located in the region where the green light emitting element 601G is to be formed using the inkjet method. did.

  <5C> Next, a tetramethylbenzene solution of a compound represented by the above general formula (6) and a tetramethylbenzene solution of a compound represented by the above general formula (21) applied in each step of 5A and 5B After drying, the substrate 621 is heated in a nitrogen atmosphere. Thus, on each of the intermediate layers 642R and 642G, a red light emitting functional layer 605R having an average thickness of 60 nm composed of the compound represented by the general formula (6), and the compound represented by the general formula (21), respectively. And a green light emitting functional layer 605G having an average thickness of 60 nm.

  <6> Next, a red light emitting functional layer 605R, a green light emitting function, which are located in a region where the red light emitting element 601R is to be formed, a region where the green light emitting element 601G is to be formed, and a region where the blue light emitting element 601B is to be formed, respectively. On the layer 605G and the anode 603B, a first hole injection layer 644 having an average thickness of 5 nm composed of the compound represented by the above formula (8) was formed by vacuum deposition.

<7> Next, a hole transport layer 643 having an average thickness of 10 nm made of α-NPD was formed on the first hole injection layer 644 using a vacuum deposition method.
<8> Next, on the hole transport layer 643, a blue light-emitting functional layer 605B having an average thickness of 20 nm composed of the following constituent materials was formed using a vacuum deposition method.
Here, as a constituent material of the blue light emitting functional layer 605B, a compound represented by the above formula (13) was used as a host material, and a compound represented by the above formula (16) was used as a guest material. The content (dope concentration) of the guest material (dopant) in the blue light emitting functional layer was 5.0% by weight with respect to the host material.

<9> Next, an electron transport layer 662 having an average thickness of 20 nm made of tris (8-quinolinolato) aluminum (Alq ₃ ) was formed on the blue light-emitting functional layer 605B by using a vacuum evaporation method.
<10> Next, a second electron injection layer 663 having an average thickness of 1.0 nm and made of lithium fluoride (LiF) was formed on the electron transport layer 662 by vacuum evaporation.

<11> Next, a cathode 608 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 663 using a vacuum deposition method.
<12> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a display device having a bottom emission structure as shown in FIG. 8 in which the formation of the first electron injection layer 361 was omitted from Example 1 was manufactured.

(Comparative Example 4R)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 721. Next, after an ITO film having an average thickness of 50 nm was formed on the substrate 721 by sputtering, the ITO film (anode 703R) was formed by patterning the ITO film using a photolithography method.
Then, the substrate 721 on which the anode 703R was formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, after an insulating layer made of an acrylic resin is formed on the substrate 721 on which the anode 703R is formed by spin coating, the ITO electrode is exposed using the photolithography method. A partition wall (bank) was formed by patterning as described above. Further, the surface of the substrate 721 on which the partition walls are formed is first plasma-treated using O ₂ gas as a processing gas. As a result, the surface of the anode 703R and the surface of the partition (including the wall surface) are activated and become lyophilic. Subsequently, the surface of the substrate 721 on which the partition walls are formed is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

  <3> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the red light emitting element 701R was to be formed, using an inkjet method. Further, after drying the applied PEDOT / PSS aqueous dispersion, the substrate 721 is heated in the atmosphere, and the ion conductive second holes having an average thickness of 50 nm made of PEDOT / PSS are formed on the anode 703R. An injection layer 741R was formed.

  <4> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the red light emitting element 701R is to be formed, using an inkjet method. did. Further, after the applied tetramethylbenzene solution of the compound represented by the general formula (5) was dried, the substrate 721 was heated in a nitrogen atmosphere. Subsequently, the region of the substrate 721 where the red light emitting element 701R was to be formed was rinsed with xylene. Thus, an intermediate layer 742R having an average thickness of 20 nm composed of the compound represented by the general formula (5) was formed on each second hole injection layer 741R.

  <5> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (6) is applied to the inside of the partition located in the region where the red light emitting element 701R is to be formed, using an inkjet method. did. Further, after drying the applied tetramethylbenzene solution of the compound represented by the general formula (6), the substrate 721 is heated in a nitrogen atmosphere. As a result, a red light emitting functional layer 705R having an average thickness of 80 nm composed of the compound represented by the general formula (6) was formed on each intermediate layer 742R.

<6> Next, a vapor deposition film containing Cs having an average thickness of 1.0 nm formed by vacuum vapor deposition using Cs ₂ CO ₃ as a vapor deposition source is formed on the red light emitting functional layer 705R, and the second electron injection layer 763.
<7> Next, a cathode 708 having an average thickness of 100 nm made of Al was formed on the second electron injection layer 763 by using a vacuum deposition method.

<8> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a red light emitting element 701R having a bottom emission structure as shown in FIG. 9 was manufactured. This red light emitting element 701R is for standardizing the characteristics of the red light emitting element 301R of Example 1, the red light emitting element 401R of Comparative Example 1, the red light emitting element 501R of Comparative Example 2, and the red light emitting element 601R of Comparative Example 3. Using.

(Comparative Example 4G)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 821. Next, an ITO film having an average thickness of 50 nm was formed on the substrate 821 by a sputtering method, and the ITO film (anode 803G) was formed by patterning the ITO film using a photolithography method.
Then, the substrate 821 on which the anode 803G was formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, an insulating layer made of an acrylic resin is formed on the substrate 821 on which the anode 803G is formed by spin coating, and then the ITO electrode is exposed using the photolithography method. A partition wall (bank) was formed by patterning as described above. Further, the surface of the substrate 821 on which the partition walls are formed is first plasma processed using O ₂ gas as a processing gas. As a result, the surface of the anode 803G and the surface of the partition wall (including the wall surface) are activated and become lyophilic. Subsequently, the surface of the substrate 821 on which the partition walls are formed is subjected to plasma processing using CF ₄ gas as a processing gas. As a result, the CF ₄ gas reacts only on the surface of the partition wall made of acrylic resin to make it liquid repellent.

  <3> Next, a 1.0 wt% PEDOT / PSS aqueous dispersion was applied to the inside of the partition located in the region where the green light emitting element 801G was to be formed, using an inkjet method. Further, after drying the applied PEDOT / PSS aqueous dispersion, the substrate 821 is heated in the atmosphere, and the ion conductive second holes having an average thickness of 50 nm composed of PEDOT / PSS are formed on the anode 803G. An injection layer 841G was formed.

  <4> Next, a 1.5 wt% tetramethylbenzene solution of the compound represented by the general formula (5) is applied to the inside of the partition located in the region where the green light emitting element 801G is to be formed, using an inkjet method. did. Furthermore, after the applied tetramethylbenzene solution of the compound represented by the general formula (5) was dried, the substrate 821 was heated in a nitrogen atmosphere. Subsequently, the region of the substrate 821 where the green light emitting element 801G was to be formed was rinsed with xylene. As a result, an intermediate layer 842G having an average thickness of 20 nm composed of the compound represented by the general formula (5) was formed on each second hole injection layer 841G.

  <5> Next, a 1.2 wt% tetramethylbenzene solution of the compound represented by the general formula (21) is applied to the inside of the partition located in the region where the green light emitting element 801G is to be formed, using an inkjet method. did. Further, after drying the applied tetramethylbenzene solution of the compound represented by the general formula (21), the substrate 821 is heated in a nitrogen atmosphere. Thereby, a green light emitting functional layer 805G having an average thickness of 80 nm composed of the compound represented by the general formula (21) was formed on each intermediate layer 842G.

<6> Next, a vapor deposition film containing Cs having an average thickness of 1.0 nm formed by vacuum vapor deposition using Cs ₂ CO ₃ as a vapor deposition source is formed on the green light emitting functional layer 805G, and the second electron injection layer 863.
<7> Next, a cathode 808 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 863 using a vacuum deposition method.

<8> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a green light emitting device 801G having a bottom emission structure as shown in FIG. 10 was manufactured. This green light emitting element 801G is for standardizing the characteristics of the green light emitting element 301G of Example 1, the green light emitting element 401G of Comparative Example 1, the green light emitting element 501G of Comparative Example 2, and the green light emitting element 601G of Comparative Example 3. Using.

(Comparative Example 4B)
<1> First, a transparent glass substrate having an average thickness of 1.0 mm was prepared as the substrate 921. Next, an ITO film having an average thickness of 50 nm was formed on the substrate 921 by a sputtering method, and then the ITO film (anode 903B) was formed by patterning the ITO film using a photolithography method.
Then, the substrate 921 on which the anode 903B was formed was immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, an insulating layer made of an acrylic resin is formed on the substrate 921 on which the anode 903B is formed by spin coating, and then the ITO electrode is exposed using the photolithography method. A partition wall (bank) was formed by patterning as described above.
<3> Next, on the anode 903B exposed inside the partition located in the region where the blue light emitting element 901B is to be formed, an average composed of the compound represented by the above formula (8) using a vacuum deposition method A first hole injection layer 944B having a thickness of 5 nm was formed.

<4> Next, a hole transport layer 943B having an average thickness of 10 nm made of α-NPD was formed on the first hole injection layer 944B by vacuum evaporation.
<5> Next, on the hole transport layer 943B, a blue light emitting functional layer 905B having an average thickness of 20 nm composed of the following constituent materials was formed using a vacuum deposition method.
Here, as a constituent material of the blue light emitting functional layer 905B, a compound represented by the above formula (13) was used as a host material, and a compound represented by the above formula (16) was used as a guest material. The content (dope concentration) of the guest material (dopant) in the blue light emitting functional layer was 5.0% by weight with respect to the host material.

<6> Next, an electron transport layer 962 having an average thickness of 20 nm made of tris (8-quinolinolato) aluminum (Alq ₃ ) was formed on the blue light-emitting functional layer 905B by vacuum evaporation.
<7> Next, a second electron injection layer 963 having an average thickness of 1.0 nm and made of lithium fluoride (LiF) was formed on the electron transport layer 962 by using a vacuum evaporation method.

<8> Next, a cathode 908 having an average thickness of 100 nm and made of Al was formed on the second electron injection layer 963 using a vacuum deposition method.
<9> Next, a glass protective cover (sealing member) was placed over the formed layers, and fixed and sealed with an epoxy resin.
Through the above steps, a blue light emitting device 901B having a bottom emission structure as shown in FIG. 11 was manufactured. This blue light emitting element 901B is for standardizing the characteristics of the blue light emitting element 301B of Example 1, the blue light emitting element 401B of Comparative Example 1, the blue light emitting element 501B of Comparative Example 2, and the blue light emitting element 601B of Comparative Example 3. Using.

2. Evaluation With respect to the display devices and light emitting elements of Examples and Comparative Examples, a constant current was passed through the light emitting elements so that the luminance was 10 cd / m ^2, and the color of the light emitted from the light emitting elements was visually observed. Observed.
Here, the reason why the low luminance value of 10 cd / m ² is selected is that, for each light emitting element of the embodiment of the present invention and each light emitting element of each comparative example, a desired value is obtained on the high luminance side (high current density side). Even if the emission color is obtained, the emission color changes as it goes to the low luminance side (low current density side), and the desired emission color may not be obtained on the low luminance side (low current density side). is there. On the contrary, if a desired emission color is obtained on the low luminance side (low current density side), the desired emission color can be obtained on the high luminance side (high current density side) without any problem. Here, obtaining a desired emission color means that red emission is obtained with a red light emitting element, green emission is obtained with a green light emitting element, and blue emission is obtained with a blue light emitting element.

In addition, for the display devices and the light emitting elements of the examples and the comparative examples, a constant current was passed through the light emitting elements so that the luminance was 1,000 cd / m ^2, and the voltage applied to the light emitting elements and the light emitting elements were emitted from the light emitting elements The current efficiency of light was measured.
Furthermore, with respect to the display devices and the light emitting elements of the examples and the comparative examples, a constant current was passed through the light emitting elements so that the initial luminance was 1,000 cd / m ^2, and the time until the initial luminance reached 80% of the initial luminance ( LT80) was measured.
And about Example 1, Comparative Examples 1, 2, and 3, the value normalized on the basis of the measured value measured by Comparative Example 4R, 4G, 4B was calculated | required.
These results are shown in Table 1.

  As is apparent from Table 1, in the display device of the example, the light emitting elements included in these are the red light emitting element 301R between the red light emitting functional layer 305R and the blue light emitting functional layer 305B, and the green light emitting element 301G emits green light. Between the functional layer 305G and the blue light emitting functional layer 305B, in the blue light emitting element 301B, between the anode 303B and the blue light emitting functional layer 305B, the first electron injecting layer 361 and the first hole injecting are provided as carrier selection layers, respectively. Since the layer 344 and the hole transport layer 343 are interposed, the red light emitting element 301R has a red light emitting functional layer 305R, the green light emitting element 301G has a green light emitting functional layer 305G, and the blue light emitting element 301B has a structure. Each of the blue light emitting functional layers 305B selectively emitted light. As a result, red light emission, green light emission, and blue light emission with high color purity were obtained in the red, green, and blue light emitting elements 301R, 301G, and 301B, respectively. Further, in all of the red, green, and blue light emitting elements 301R, 301G, and 301B, in Example 1, a high normalized current efficiency of 0.87 or more was obtained, and the elements were excellent in luminous efficiency. Further, in all of the red, green, and blue light emitting elements 301R, 301G, and 301B, an excellent standardized lifetime of 0.70 or more was obtained in Example 1, and the lifetime was extended. In addition, the normalized voltages of the red and green light emitting elements 301R and 301G were suppressed to 1.16 or less in Example 1, and excellent characteristics were obtained from the viewpoint of driving voltage.

  In contrast to Example 1, in the display device of Comparative Example 1, the insertion of the first electron injection layer 361, the first hole injection layer 344, and the hole transport layer 343 is omitted. Therefore, in the red light emitting element 401R and the green light emitting element 401G, electrons are not smoothly injected from the blue light emitting functional layer 405B to the red light emitting functional layer 405R and the green light emitting functional layer 405G, respectively. As a result, red and green In addition to this, the blue light was emitted. As a result, in the red light emitting element 401R and the green light emitting element 401G, the color purity of red and green respectively decreased significantly. This is because, in the red light emitting element 401R and the green light emitting element 401G of Comparative Example 1, the electron injecting property from the blue light emitting functional layer 405B to the red light emitting functional layer 405R or the green light emitting functional layer 405G is insufficient. This is because not only the functional layer 405R or the green light emitting functional layer 405G but also the blue light emitting functional layer 405B emits light simultaneously.

  Further, the normalized lifetimes (LT80) of the red light emitting element 401R and the green light emitting element 401G of Comparative Example 1 were as low as 0.13 and 0.38, respectively. This is because, in the red light emitting element 401R and the green light emitting element 401G of Comparative Example 1, the electron injecting property from the blue light emitting functional layer 405B to the red light emitting functional layer 405R or the green light emitting functional layer 405G is insufficient. This is considered to be because the deterioration due to electrons at the cathode 408 side interface of the functional layer 405R or the green light emitting functional layer 405G was large.

  Further, the normalized lifetime of the blue light emitting element 401B of Comparative Example 1 was a low value of 0.29. This is because the hole transport layer 443B of the blue light emitting element 401B of Comparative Example 1 was formed by an inkjet method. That is, if a vapor phase process such as vacuum deposition is used, the next blue light emitting functional layer 405B is continuously formed without exposing the cathode 408 side interface of the hole transport layer 443B to an atmosphere other than vacuum. However, when a liquid phase process such as an inkjet method is used, it is difficult to form the hole transport layer 443B in a vacuum atmosphere. This is performed in an atmosphere (eg, air or nitrogen), and at least the cathode 408 side interface of the hole transport layer 443B is exposed to an atmosphere other than vacuum. When the hole transport layer 443B is formed using a liquid phase process in this manner, the cathode 408 side interface of the hole transport layer 443B is easily contaminated, which shortens the lifetime of the blue light emitting element 401B. In addition, when the hole transport layer 443B is formed by a liquid phase process, since a solution in which a hole transport material is dissolved in a solvent is used for film formation, a very small amount of solvent remains in the hole transport layer 443B. This contaminates the whole hole transport layer 443B, so that the lifetime of the blue light emitting element 401B is shortened.

In contrast, the normalized lifetime of the blue light emitting element 301B of Example 1 was as high as 0.92. This is presumably because the formation of the hole transport layer and the hole injection layer using the liquid phase process was omitted, and the contamination due to the formation of these layers was eliminated.
In addition, the normalized voltages of the red light emitting element 401R and the green light emitting element 401G of Comparative Example 1 were as high as 1.25 and 1.27. This is because, in the red light emitting element 401R and the green light emitting element 401G of Comparative Example 1, the electron injecting property from the blue light emitting functional layer 405B to the red light emitting functional layer 405R or the green light emitting functional layer 405G is insufficient. It is considered that a state in which the energy barrier against electrons at the cathode 408 side interface of the functional layer 405R and the green light emitting functional layer 405G occurs is high, and as a result, the drive voltage increases by 20% or more.

  Further, in the display device of Comparative Example 2, the insertion of the first hole injection layer 344 and the hole transport layer 343 with respect to Example 1 is omitted. However, in the red light emitting element 501R and the green light emitting element 501G, the first electron injection layer 561 exists between the blue light emitting functional layer 505B, the red light emitting functional layer 505R, and the green light emitting functional layer 505G. Electrons are smoothly injected from 505B to the red light emitting functional layer 505R and the green light emitting functional layer 505G. As a result, only the red light emitting functional layer 505R is used in the red light emitting element 501R and the green light emitting functional layer 505G is used in the green light emitting element 501G. Only selectively emitted light and was able to suppress the light emission of the blue light emitting functional layer 505B. However, since the first electron injection layer 561 is in contact with the blue light emitting functional layer 505B in the blue light emitting element 501B, the first electron injection layer 561 hinders the light emission of the blue light emitting functional layer 505B. The normalized current efficiency and the normalized lifetime were extremely low, which is far from the practical level of characteristics.

Further, in the display device of Comparative Example 3, the insertion of the first electron injection layer 361 is omitted with respect to Example 1.
For this reason, in the red light emitting element 601R, electrons are not smoothly injected from the blue light emitting functional layer 605B to the hole transport layer 643 and from the hole transport layer 643 to the red light emitting functional layer 605R. For this reason, the red light emitting functional layer 605R hardly emitted light, and the blue light emitting functional layer 605B emitted light strongly.

Similarly, in the green light emitting element 601G of the display device of Comparative Example 3, injection of electrons from the blue light emitting functional layer 605B to the hole transport layer 643 and injection of electrons from the hole transport layer 643 to the green light emitting functional layer 605G are performed. Not smoothly. For this reason, the green light emitting functional layer 605G hardly emitted light, and the blue light emitting functional layer 605B emitted light strongly.
That is, in the display device of Comparative Example 3, all of the red light emitting element 601R, the green light emitting element 601G, and the blue light emitting element 601B emitted blue light.

  The results of the above examples and comparative examples are summarized as follows. First, in the red light emitting element and the green light emitting element, it was in Example 1 and Comparative Example 2 that a desired emission color and a practical life of 0.60 or more were obtained. However, the current efficiency of the blue light emitting element 501B of Comparative Example 2 was extremely low and the lifetime was extremely short, so Comparative Example 2 did not reach a practical level as a display device.

Next, in the blue light-emitting element, it was in Example 1 and Comparative Example 3 that a desired emission color and a standardized lifetime of 0.60 or more were obtained. However, since the red light emitting element 601R and the green light emitting element 601G of Comparative Example 3 emitted blue light, they did not reach a practical level as a display device.
As described above, only Example 1 has reached a practical level as a display device.

  In all of the red light emitting element 301R, the green light emitting element 301G, and the blue light emitting element 301B of Example 1 of the present invention, the desired colors were obtained by the first electron injection layer 361 and the first hole injection layer. This is because the stack of 344 and the hole transport layer 343 functioned as a carrier selection layer. In addition, in the red light emitting element 301R and the green light emitting element 301G of Example 1 of the present invention, the standardized lifetime of 0.60 or more was obtained because the first electron injection layer 361 and the first hole injection layer 344 were used. This is because the stacked body of the hole transport layer 343 functions as a carrier selection layer. Further, in the blue light emitting device 301B of the example of the present invention, the standardized lifetime of 0.60 or more was obtained because of the first electron injection layer 361, the first hole injection layer 344, and the hole transport. This is because the stack with the layer 343 functions as a carrier selection layer, and the first electron injection layer 361 and the anode 303B are formed by vacuum deposition so that they are in contact with each other.

(Modification 1)
In the present embodiment, the light-emitting elements of the present invention are applied to the light-emitting elements 1R, 1G, and 1B, and the third layers of the light-emitting elements 1R and 1G are the red light-emitting functional layer 5R and the green light-emitting functional layer 5G, respectively. In addition, the case where the first layer of the light emitting elements 1R and 1G is the blue light emitting functional layer 5B has been described. However, the application range of the present invention is not limited to such a case, and the third layer and the first layer of the light emitting elements 1R and 1G may be light emitting functional layers having different light emission colors. The third layers of the elements 1R and 1G may emit yellow and orange, respectively, and the first layer emits green light. In this case, the light emitting element 1R includes a yellow light emitting functional layer instead of the red light emitting functional layer 5R, and the light emitting element 1G includes an orange light emitting functional layer instead of the green light emitting functional layer 5G. Furthermore, the light emitting elements 1R and 1G include a green light emitting functional layer instead of the blue light emitting functional layer 5B.
However, as in the present embodiment, the red light emitting functional layer 5R and the green light emitting functional layer 5G are applied to the third layers of the light emitting elements 1R and 1G, and the blue light emitting functional layer 5B is applied to the first layer. It is preferable.

(Modification 2)
In the present embodiment, the case where the display device 100 is applied to a display panel having a bottom emission structure that extracts light from the substrate 21 side has been described. However, the present invention is not limited to this, and the top emission structure that extracts light from the sealing substrate 20 side is described. It can be applied to other display panels. As a result, the color reproduction range of the display apparatus 100 can be improved.

(Modification 3)
In the present embodiment, when the light R, G, B of the display device 100 is transmitted from the substrate 21 side, a color filter (color conversion layer) corresponding to each light is not provided, but the surface in contact with the substrate 21 or the substrate 21 may have a structure having color filters provided corresponding to the sub-pixels 100R, 100G, and 100B. As a result, the color reproduction range of the display apparatus 100 can be improved.

1R, 301R, 401R, 501R, 601R, 701R ... Red light emitting element 1G, 301G, 401G, 501G, 601G, 801G ... Green light emitting element 1B, 301B, 401B, 501B, 601B, 901B, 2101B, 2201B ... Blue Light-emitting elements 3R, 3G, 3B, 303R, 303G, 303B, 403R, 403G, 403B, 503R, 503G, 503B, 603R, 603G, 603B, 703R, 803G, 903B, 2103B, 2203B ... Anodes 41R, 41G, 41B, 341R, 341G, 341B, 441R, 441G, 441B, 541R, 541G, 541B, 641R, 641G, 641B, 741R, 841G, 941B, 2141B, 2241B ... 2nd hole injection layer 42R, 42G, 3 42R, 342G, 442R, 442G, 542R, 542G, 642R, 642G, 742R, 842G ... intermediate layer 43, 343, 443B, 543B, 643, 943B, 2143B, 2243B ... hole transport layer 44, 344, 644, 944B... First hole injection layer 46... Carrier selection layer 5R, 305R, 405R, 505R, 605R, 705R... Red light emitting functional layer 5G, 305G, 405G, 505G, 605G, 805G. , 305B, 405B, 505B, 605B, 905B, 2105B, 2205B ... Blue light emitting functional layer 61, 361, 561, 2261B ... First electron injection layer 63, 363, 463, 563, 663, 763, 863, 963, 2163, 2263... Second electron injection layer 62, 3 2, 462, 562, 662, 962, 2162, 2262 ... Electron transport layer 8, 308, 408, 508, 608, 708, 808, 908, 2108, 2208 ... Cathode 100 ... Display device 100R, 100G, 100B …… Sub-pixel 20 ...... Sealing substrate 21, 321, 421, 521, 621, 721, 821, 921, 2221, 2221 ...... Substrate 22 ...... Planeization layer 24 …… Drive transistor 241 …… Semiconductor layer 242 ...... Gate insulating layer 243 ...... Gate electrode 244 ...... Source electrode 245 ...... Drain electrode 27 ...... Wiring 31 ...... Partition 35 ...... Epoxy layer 1100 ...... Personal computer 1102 ...... Keyboard 1104 ...... Main body 1106 ...... Display unit 1200 …… Cellular phone 1202 …… Operation button 1204 .. Earpiece 1206... Mouthpiece 1300 .. Digital still camera 1302 .. Case (body) 1304 .. Light receiving unit 1306 .. Shutter button 1308 .. Circuit board 1312 .. Video signal output terminal 1314. Communication input / output terminal 1430 ... TV monitor 1440 ... Personal computer

Claims (12)

A cathode,
An anode composed mainly of a metal oxide,
A blue light emitting functional layer having a function of emitting blue light provided between the anode and the cathode;
Between the blue light emitting functional layer and the anode, from the blue light emitting layer functional layer side, there is a carrier selection layer in which a hole transport layer, a hole injection layer, and an electron injection layer are laminated in this order. ,
The light-emitting element, wherein the carrier selection layer is provided on the electron injection layer side so as to be in contact with the anode.   The light-emitting element according to claim 1, wherein the electron injection layer is composed of a metal-based material as a main material.   The light emitting device according to claim 1, wherein the metal oxide is ITO.   4. The light emitting device according to claim 1, wherein the blue light emitting functional layer and the carrier selection layer are formed using a gas phase process. 5.   5. The light emitting device according to claim 1, wherein the carrier selection layer exhibits a function of inhibiting electrons from escaping from the cathode side to the anode side.   A display device comprising the light-emitting element according to claim 1. A light emitting device according to any one of claims 1 to 5 and a long wavelength light emitting device that emits light having a longer wavelength than blue,
The long-wavelength light emitting device has the cathode, the blue light emitting functional layer, the carrier selection layer, and the anode,
The display device further comprises a long-wavelength light emitting functional layer having a function of emitting light having a longer wavelength than blue provided between the carrier selection layer and the anode.   In the long wavelength light emitting device, by applying a voltage between the anode and the cathode, light emission of the blue light emitting functional layer is significantly suppressed, and the long wavelength light emitting functional layer is selectively or dominant. The display device according to claim 6 which emits light.   The display device according to claim 6, wherein the long wavelength light emitting functional layer is a red light emitting functional layer having a function of emitting red light.   The display device according to claim 6, wherein the long wavelength light emitting functional layer is a green light emitting functional layer having a function of emitting green light.   11. The display device according to claim 6, wherein in the long wavelength light emitting element, the carrier selection layer exhibits a function of allowing electrons to escape from the cathode side to the anode side.   An electronic apparatus comprising the display device according to claim 6.

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