JP2008165988A - Manufacturing method of light emitting device, light emitting device, and electronic device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a light emitting device capable of easily manufacturing the light emitting device with excellent light emission efficiency and durability, the light emitting device with excellent characteristics manufactured by the manufacturing method of the light emitting device, and an electronic device with high reliability. <P>SOLUTION: The manufacturing method of the light emitting device includes a first process for forming a negative electrode 8 containing metal ions and conductive polymer material on an upper substrate 9, a second process for forming a positive electrode 3, a hole transport layer 4, a light emitting layer 5, and an electron transport layer 6 containing an organic compound with an electron transport property which contains at least one element having a unshared electron pair on a TFT circuit substrate 20 in this order from a TFT circuit substrate 20 side, and a third process for abutting the negative electrode 8 and the electron transport layer 6 by contacting a surface opposite to the upper substrate 9 of the negative electrode 8 and a surface opposite to a light emitting layer 5 side of the electron transport layer 6, and heating and pressurizing the upper substrate 9 and the TFT circuit substrate 20, and diffusing the metal ions contained in the negative electrode 8 on the electron transport layer 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

An organic EL element (light emitting device) has a structure in which an organic layer including a thin film (light emitting layer) containing at least a fluorescent organic compound is sandwiched between a cathode and an anode. In this element, excitons (excitons) are generated by injecting and recombining holes), and light is emitted using light emission (fluorescence / phosphorescence) when the excitons are deactivated.
This organic EL element can emit surface light with a high luminance of about 100 to 100,000 cd / m ² at a low voltage of 10 V or less, and can emit light from blue to red by selecting the type of fluorescent material. It has attracted attention as an element that can realize a large area full color display at low cost.

Currently, in order to obtain a higher performance organic EL element, a device structure in which various layers are provided between a cathode and a light emitting organic layer (light emitting layer) or between an anode and a light emitting layer has been proposed. There is active research.
One such layer is an electron transport layer provided between the cathode and the light-emitting layer, and an electron injection layer provided between the electron transport layer and the cathode. Improvement of the layer performance is urgent because it greatly depends on device characteristics.

For example, in Patent Document 1, by co-evaporating an electron transporting organic compound and a metal compound containing an alkali metal that is a metal having a low work function, by mixing the metal compound into the electron injection layer, A configuration for improving the characteristics of the electron injection layer has been proposed.
However, in an organic EL device having an electron injection layer having such a configuration, the metal compound contained in the electron injection layer is in contact with the light emitting layer, and the light emitting material contained in the light emitting layer is brought into contact with the metal compound over time. Due to the deterioration, characteristics such as the light emission efficiency of the organic EL element are lowered, and it is difficult to say that the durability has been improved.

JP-A-10-270171

  An object of the present invention is to provide a light emitting device manufacturing method capable of easily manufacturing a light emitting device excellent in luminous efficiency and durability, a light emitting device excellent in characteristics manufactured by the method of manufacturing such a light emitting device, and a reliable It is to provide high electronic equipment.

Such an object is achieved by the present invention described below.
The method for manufacturing a light emitting device according to the present invention includes, on a first substrate, at least one metal ion of alkali metal ions, alkaline earth metal ions, and rare earth metal ions, and a conductive polymer material. A first step of forming a negative electrode;
On the second substrate, at least an anode, a light-emitting layer, and a layer containing an electron-transporting organic compound containing at least one element having an unshared electron pair and having a function of transporting electrons are arranged in this order. And a second step of forming from the second substrate side,
A surface opposite to the first substrate side of the cathode and a surface opposite to the light emitting layer side of the layer having a function of transporting electrons are brought into contact with each other, and the first substrate and the second substrate are brought into contact with each other. By heating and pressurizing the substrate, the cathode and the layer having a function of transporting the electrons are joined, and the metal ions contained in the cathode are diffused into the layer having a function of transporting the electrons. And a third step.
Thereby, the layer which has the function to convey the electron excellent in electron transport efficiency can be formed, and the light-emitting device excellent in luminous efficiency and durability can be manufactured easily.

In the method for manufacturing a light emitting device of the present invention, in the third step, the layer having a function of transporting the electrons after being joined to the cathode is configured to transfer the metal ions from the cathode side to the light emitting layer side. It is preferably formed with a concentration gradient such that the concentration decreases toward the surface.
As a result, it is possible to reliably prevent the metal ions diffused in the layer having a function of transporting electrons from being mixed into the light emitting layer, and to reduce the emission luminance of the light emitting layer over time caused by the mixing of metal ions. Is suppressed. That is, the light emitting device has excellent durability.

In the method for manufacturing a light emitting device of the present invention, in the third step, the first substrate and the second substrate are heated simultaneously with or immediately after the first substrate and the second substrate are heated and pressurized. It is preferable to promote diffusion of the metal ions to the layer having a function of transporting the electrons from the cathode by performing a predetermined treatment on at least one of the two substrates.
Thereby, the diffusion amount of metal ions to the layer having a function of transporting electrons can be increased, and the function of transporting electrons from the cathode can be obtained by appropriately setting the processing conditions of the predetermined processing. The amount of diffusion of metal ions into the layer can be easily controlled.

In the method for manufacturing a light emitting device of the present invention, it is preferable that diffusion of the metal ions into the layer having a function of transporting electrons is promoted by applying a voltage between the cathode and the anode.
Thereby, it is possible to increase the diffusion amount of metal ions to the layer having a function of transporting electrons with a relatively simple configuration, and by appropriately setting the processing conditions of this predetermined processing, The amount of diffusion of metal ions into the layer having a function of transporting electrons can be easily controlled.

In the method for manufacturing a light emitting device of the present invention, the diffusion of the metal ions into the layer having a function of transporting electrons is caused by vibrating at least one of the cathode and the layer having a function of transporting electrons. It is preferred that it be promoted.
Thereby, it is possible to increase the diffusion amount of metal ions to the layer having a function of transporting electrons with a relatively simple configuration, and by appropriately setting the processing conditions of this predetermined processing, The amount of diffusion of metal ions into the layer having a function of transporting electrons can be easily controlled.

In the method for manufacturing a light emitting device of the present invention, the conductive polymer material is preferably composed of a polymer compound containing an ethylenedioxythiophene skeleton.
When the conductive polymer material is composed of such a polymer compound, the cathode can exhibit particularly excellent conductivity by doping the metal ions.
In the method for manufacturing a light emitting device of the present invention, the element having an unshared electron pair is preferably at least one of N, O, P, S, As, and Se.
Thereby, the structure of the organic compound can be further stabilized, and the metal ions diffused from the cathode can be stably captured. Thereby, the layer having the function of transporting electrons can hold the metal ions sufficient to improve the electron transport ability, and the metal ions diffuse to the vicinity of the interface with the light emitting layer. Can be suppressed.

In the method for manufacturing a light-emitting device of the present invention, the electron-transporting organic compound is preferably a condensed heterocyclic compound containing an element having the lone pair or a derivative thereof.
By having these structures, in the structure of the organic compound, an electron density bias to an element having an unshared electron pair is more likely to occur, and as a result, the structure of the organic compound is more reliably stabilized. Made.

In the method for manufacturing a light-emitting device of the present invention, the electron-transporting organic compound forms the bond because the element having the lone pair is bonded to another element by a double bond or a triple bond. It is preferable to have polarization between the two elements.
By having these structures, in the structure of the organic compound, an electron density bias to an element having an unshared electron pair is more likely to occur, and as a result, the structure of the organic compound is more reliably stabilized. Made.

In the method for manufacturing a light emitting device of the present invention, in the third step, the layer having a function of transporting the electrons after being joined to the cathode has a thickness of D, and is included in the organic compound. A number obtained by subtracting the number of double or triple bonds between the elements from the total number of elements having an unshared electron pair is A [number], and the number of the metal ions is B [number] The B / A is preferably 0.2 or more at a thickness of D × 1/5 from the interface with the cathode.
Thereby, the said metal ion can be made to exist without excess and deficiency with respect to the said organic compound, and the structure of the said organic compound can be stabilized more reliably. Further, the efficiency of electron injection into the layer having a function of transporting electrons from the cathode by the action of the metal ions can be sufficiently improved. For this reason, the characteristics of the layer having a function of transporting electrons can be further improved.

In the method for manufacturing a light emitting device of the present invention, in the third step, the layer having a function of transporting the electrons after being joined to the cathode has a thickness of D, and is included in the organic compound. A number obtained by subtracting the number of double or triple bonds between the elements from the total number of elements having an unshared electron pair is A [number], and the number of the metal ions is B [number] It is preferable that B / A is 0.1 or less at a thickness of D × 2/3 from the interface with the cathode.
Thereby, it is possible to reliably prevent the metal ions contained in the layer having a function of transporting electrons from diffusing into the light emitting layer.

The light emitting device according to the present invention is manufactured by the method for manufacturing a light emitting device of the present invention.
Thereby, a light emitting device having excellent characteristics can be obtained.
An electronic apparatus according to the present invention includes the light emitting device of the present invention.
As a result, a highly reliable electronic device can be obtained.

Hereinafter, a method for manufacturing a light emitting device, a light emitting device, and an electronic apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
First, an embodiment of an active matrix display device to which the light emitting device of the present invention is applied will be described.
FIG. 1 is a longitudinal sectional view showing an embodiment of an active matrix display device to which the light emitting device of the present invention is applied, and FIG. 2 is a view for explaining a method of manufacturing the active matrix display device shown in FIG. . In the following description, the upper side in FIGS. 1 and 2 is referred to as “upper” and the lower side is referred to as “lower”.

An active matrix display device (hereinafter simply referred to as “display device”) 10 shown in FIG. 1 includes a TFT circuit substrate (counter substrate) 20, a light emitting element 1 provided on the base 20, and a TFT circuit substrate. 20 and an upper substrate 9 facing to each other.
The TFT circuit substrate 20 includes a substrate 21 and a circuit unit 22 formed on the substrate 21.

The substrate (second substrate) 21 serves as a support for each part of the display device 10, and the upper substrate (first substrate) 9 functions as, for example, a protective layer that protects the light emitting element 1. To do.
In addition, since the display device 10 according to the present embodiment has a configuration for extracting light from the substrate 21 side (bottom emission type), the substrate 21 is substantially transparent (colorless transparent, colored transparent, translucent). The upper substrate 9 is not particularly required to be transparent.

Although both the substrate 21 and the upper substrate 9 may be configured by a flexible substrate or a hard substrate, in the present embodiment, the substrate 21 is configured by a hard substrate, and the upper substrate 9 is a flexible substrate. It is configured.
Various glass material substrates are suitable for the substrate 21, but various high-hardness resin substrates can also be used.

  On the other hand, as the upper substrate 9, a substrate composed mainly of a polyether resin such as polyimide resin, polyester resin, polyamide resin, polyether ether ketone, polyether sulfone, or the like can be used. Especially, since the polyimide resin has a small coefficient of thermal expansion and thermal contraction, a substrate mainly made of polyimide resin can keep the thermal contraction rate low. Moreover, the board | substrate comprised using a polyester-type resin as a main material has the advantage that dimensional stability is good.

Furthermore, the shrinkage rate of the upper substrate 9 can be reduced and the dimensional stability can be improved by laminating fillers and fibers in such a resin material, or by adjusting the pre-heat treatment and the degree of crosslinking. .
In addition, the flexible substrate which comprises the upper board | substrate 9 can also comprise carbon system materials, such as a ceramic material, a metal material, carbon fiber, etc. as a main material other than a resin material, for example.

Although the average thickness of the board | substrate 21 is not specifically limited, It is preferable that it is about 1-30 mm, and it is more preferable that it is about 5-20 mm. On the other hand, the average thickness of the upper substrate 9 is not particularly limited, but is preferably about 0.1 to 30 mm, and more preferably about 0.1 to 10 mm.
The circuit unit 22 includes a base protective layer 23 formed on the substrate 21, a driving TFT (switching element) 24 formed on the base protective layer 23, a first interlayer insulating layer 25, and a second interlayer insulating layer. 26.

The driving TFT 24 includes a semiconductor layer 241, a gate insulating layer 242 formed on the semiconductor layer 241, a gate electrode 243 formed on the gate insulating layer 242, a source electrode 244, and a drain electrode 245. ing.
On such a circuit portion 22, the light emitting element 1 is provided corresponding to each driving TFT 24. Adjacent light emitting elements 1 are partitioned by a partition wall (bank) 31.

In the present embodiment, the anode 3 of each light emitting element 1 constitutes a pixel electrode and is electrically connected to the drain electrode 245 of each driving TFT 24 by the wiring 27. Moreover, the electron transport layer 6 of each light emitting element 1 is integrally formed, and the cathode 8 is a common electrode.
The display device 10 may be monochromatic display, and color display is also possible by selecting a light emitting material used for each light emitting element 1.

Hereinafter, the light emitting element 1 will be described in detail.
As shown in FIG. 1, the light-emitting element 1 includes a positive hole transport layer 4, a light-emitting layer 5, and an electron transport layer (in order from the anode 3 side) between the anode 3, the cathode 8, and the anode 3 and the cathode 8. A layer 6 having a function of transporting electrons) is interposed.
The anode 3 is an electrode that injects holes into the hole transport layer 4.

As a constituent material (anode material) of the anode 3, it is preferable to use a material having a large work function, excellent conductivity, and translucency.
Examples of such an anode material include ITO (composite of indium oxide and zinc oxide), oxides such as SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, Ag, Cu, or these. An alloy etc. are mentioned, At least 1 sort (s) of these can be used.

  The average thickness of the anode 3 is not particularly limited, but is preferably about 10 to 200 nm, and more preferably about 50 to 150 nm. If the thickness of the anode 3 is too thin, the function as the anode 3 may not be sufficiently exhibited. On the other hand, if the anode 3 is too thick, the light transmittance may be remarkably lowered depending on the type of anode material. When the structure of the organic EL element 1 is a bottom emission type, it may not be suitable for practical use.

On the other hand, the cathode 8 is an electrode for injecting electrons into the electron transport layer 6.
In the present invention, the cathode 8 is composed of a conductive polymer material as a main material, and is composed of at least one metal ion (hereinafter simply referred to as “metal ion”) of alkali metal ions, alkaline earth metal ions, and rare earth metal ions. ").”
Here, for example, if the cathode 8 is made of a metal film, there is a possibility that a short circuit may occur between the anode 3 and the cathode 8 due to metal migration and surface roughness of the metal film. Further, when a voltage is repeatedly applied between the anode 3 and the cathode 8, an organic film (in this embodiment, an electron transport layer 6) provided in contact with the surface of the cathode 8 due to the catalytic action of the metal. ) Is made of an organic material unstable to metal, there is a problem that this organic material may be altered or deteriorated.

On the other hand, as in the present invention, the cathode 8 is composed of a conductive polymer material as a main material, so that a short circuit caused by the characteristics of the metal film as described above or deterioration / deterioration of the organic material occurs. Can be reliably prevented.
Furthermore, in the present invention, since the cathode 8 (cathode forming material described later) contains metal ions, the first laminate is produced when the display device 10 is manufactured by the method for manufacturing a light emitting device described later. In the bonding step between 101 and the second laminate 102, metal ions contained in the cathode 8 are diffused into the electron transport layer 6. Thereby, the electron transport layer 6 excellent in electron transport efficiency can be obtained. As a result, the obtained display device 10 can obtain high luminance even when the voltage applied between the anode 3 and the cathode 8 is relatively low. That is, the display device 10 that is driven at a low voltage and has excellent luminous efficiency characteristics can be obtained.

  The conductive polymer material is not particularly limited as long as it exhibits conductivity by having a conjugated bond in the polymer chain. For example, an ethylenedioxythiophene skeleton is used. And a high molecular compound having one or more of a phenylene skeleton such as a thiophene skeleton, a paraphenylene skeleton, and a paraphenylene vinylene skeleton, a pyrrole skeleton, a styrene skeleton, and an acetylene skeleton. Among these, it is preferable to use a polymer compound having a pyrrole skeleton, and it is more preferable to use polypyrrole. The polymer compound having a pyrrole skeleton can be suitably used as a constituent material of the cathode 8 because it exhibits particularly excellent conductivity when doped with metal ions or metals. When doping metal, the metal doped in the conductive polymer gives electrons to the conductive polymer and becomes metal ions. Therefore, even if the state before doping is a metal state, after doping, it exists as a metal ion in the conductive polymer.

In the present invention, the cathode 8 includes metal ions, that is, the conductive polymer material is doped with metal ions. With this configuration, the conductivity of the conductive polymer material, that is, the cathode 8, can be improved.
As described in the manufacturing method of the display device 10 to be described later, the metal ions are configured to diffuse the metal ions contained in the cathode 8 into the electron transport layer 6 in the present invention. The same thing as the metal ion contained in the transport layer 6 is mentioned. In addition, the metal ion content in the cathode 8 is determined by the bonding process from the metal ion content in the cathode 8 before the bonding process between the first stacked body 101 and the second stacked body 102 is performed. 6 is the balance obtained by subtracting the amount of metal ions diffused. The content of metal ions in the cathode 8 before the bonding step and the amount of metal ions diffused from the cathode 8 and contained in the electron transport layer 6 will be described later.

The average thickness of the cathode 8 is not particularly limited, but is preferably about 5 to 150 nm, and more preferably about 10 to 100 nm. If the thickness of the cathode 8 is too thin, the function as the cathode 8 may not be sufficiently exhibited. On the other hand, if the cathode 8 is too thick, the flexibility of the first laminate 101 described later may be reduced. There is.
An auxiliary electrode (not shown) may be provided so as to cover the upper substrate 9 side of the cathode 8. As a result, the cathode 8 and the auxiliary electrode function as a common cathode even if the electrical resistance of the cathode 8 is increased by the combination of the conductive polymer material and the metal ions contained in the cathode 8. The overall conductivity can be improved.

The auxiliary cathode also has a function of covering the cathode 8 and protecting the cathode 8 from oxygen, moisture, and the like.
The auxiliary cathode is composed of conductive metal fine particles.
The metal fine particle is not particularly limited as long as it is a chemically stable conductive material. For example, a metal such as Al (aluminum), Au (gold), Ag (silver) or an alloy thereof is preferably used. .

Although the thickness of an auxiliary cathode is not specifically limited, It is preferable that it is about 100-500 nm, and it is more preferable that it is about 150-250 nm.
The hole transport layer 4 has a function of transporting holes injected from the anode 3 to the light emitting layer 5.
As a constituent material (hole transport material) of the hole transport layer 4, various polymer materials and various low molecular materials can be used alone or in combination.

Examples of the polymer hole transport material include those having an arylamine skeleton such as polyarylamine, those having a fluorene skeleton such as a fluorene-bithiophene copolymer, poly (N-vinylcarbazole), and polyvinylpyrene. , Polyvinyl anthracene, polythiophene, ethyl carbazole formaldehyde resin or a derivative thereof.
Moreover, the said compound can also be used as a mixture with another compound. As an example, the polythiophene-containing mixture includes poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS).

On the other hand, examples of low molecular hole transport materials include arylcycloalkane compounds such as 1,1′-bis (4-di-para-tolylaminophenyl) -4-phenyl-cyclohexane, and 4,4 ′. Arylamine compounds such as 4,4 "-trimethyltriphenylamine, phenylenediamine compounds such as N, N, N ', N'-tetraphenyl-para-phenylenediamine, and carbazoles such as N-phenylcarbazole System compounds and the like.
The average thickness of the hole transport layer 4 is not particularly limited, but is preferably about 10 to 150 nm, and more preferably about 50 to 100 nm.

Further, for example, a hole injection layer that improves the efficiency of hole injection from the anode 3 may be provided between the anode 3 and the hole transport layer 4.
As a constituent material (hole injection material) of this hole injection layer, for example, copper phthalocyanine, 4,4 ′, 4 ″ -tris (N, N-phenyl-3-methylphenylamino) triphenylamine ( m-MTDATA) and the like.

Note that the hole transport layer 4 and the hole injection layer as described above may be omitted depending on the combination of the anode 3, the light emitting layer 5, the electron transport layer 6, and the cathode 8.
An electron transport layer 6 is provided on the light emitting layer 5. The electron transport layer 6 has a function of transporting electrons injected from the cathode 8 to the light emitting layer 5.
In the present invention, the electron transport layer 6 is an electron transporting organic compound containing at least one element having an unshared electron pair (hereinafter, simply referred to as “electron transporting organic compound” or “organic compound”). In which the metal ions in the cathode 8 are diffused in the bonding step of the first laminate 101 and the second laminate 102 in the method of manufacturing the display device 10 to be described later. Contains.

In the electron transport layer 6, since metal ions are diffused from the cathode 8, they are included in a concentration gradient such that the concentration decreases from the cathode 8 side toward the light emitting layer 5 side.
As described above, in the present invention, the electron transport layer 6 has a structure including a metal ion in addition to an electron transporting organic compound (an organic compound having a function of transporting electrons), and thus, an excellent electron. Exhibits transportability. Thereby, even if the voltage applied between the anode 3 and the cathode 8 is relatively low, the display device 10 can efficiently inject electrons into the light emitting layer 5 and obtain high luminance.

  The improvement of the electron transport property is that the metal ion is an alkali metal, alkaline earth metal or rare earth metal and has a low work function, so that the injection efficiency of electrons from the cathode 8 to the electron transport layer 6 is improved. And a chemical interaction (for example, ionic bond, coordination bond, etc.) between the metal ion and the element having an unshared electron pair contained in the organic compound, the energy level of the organic compound is relatively Change, that is, HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) change to a relatively low level, thereby reducing the electron injection barrier. This is presumably due to easier electron injection. As a result of improving the electron transport characteristics and the efficiency of electron injection from the cathode 8, in the light emitting device 1, the electron injection into the light emitting layer 5 is more effectively performed, the light emission luminance is increased, and the driving voltage is decreased. Furthermore, due to the decrease in the HOMO level, the holes that have not been recombined are suppressed from being sent to the cathode 8, and holes are effectively accumulated at the interface between the light emitting layer 5 and the electron transport layer 6. As a result, these holes can contribute to recombination again, and the luminous efficiency is improved.

The metal ions are contained in the electron transport layer 6 with a concentration gradient such that the concentration decreases from the cathode 8 side toward the light emitting layer 5 side, as described above.
Here, when metal ions are contained in the electron transport layer 6 at a uniform concentration, the metal ions existing in the vicinity of the interface between the electron transport layer 6 and the light-emitting layer 5 are repeatedly passed over time and voltage application. Along with this, it diffuses into the light emitting layer 5. And in a light emitting layer 5, when a metal ion and a light emitting material contact, a light emitting material will change and deteriorate, and the problem that the light emission luminance of the light emitting layer 5 will fall arises.

  On the other hand, in the present invention, in the electron transport layer 6, the metal ions are included in a concentration gradient such that the concentration decreases from the cathode 8 side toward the light emitting layer 5 side. In the vicinity of the interface, the concentration of metal ions can be extremely low or substantially free of metal ions. That is, the electron transport layer 6 can also function as a barrier layer that prevents the metal ions and the light-emitting material contained in the light-emitting layer 5 from contacting each other. As a result, the metal ions contained in the electron transport layer 6 can be prevented or suppressed from diffusing into the light emitting layer 5, and the temporal decrease in light emission luminance due to the metal ions mixed into the light emitting layer 5 can be suppressed. . That is, the light emitting element 1 (display device 10) has excellent durability.

  Here, as an element having an unshared electron pair contained in the electron-transporting organic compound, elements belonging to Group 5B such as N, P, As, Sb, and Bi, O, S, Se, Te, and Po An element belonging to Group 6B, such as F, Cl, Br, I, and At, and an element belonging to Group 7B, such as at least one of N, O, P, S, As, and Se. Is preferred. Since these elements have a reasonably high electronegativity, electrons can be slightly biased toward the element side in the structure of the organic compound. For this reason, the chemical interaction between the organic compound and the metal ion can be further increased. As a result, the structure of the organic compound can be further stabilized and the metal ion diffused from the cathode 8 can be stably captured. . Thereby, the electron transport layer 6 can hold | maintain metal ion sufficient to improve the electron transport capability, and suppresses that a metal ion diffuses to the interface vicinity with the light emitting layer 5. FIG. be able to. In addition, since these elements have a moderately high bond order, they have unpaired electrons that interact with metal ions and easily form bonds with other elements. As a result, it can be inserted into various organic compounds.

In addition, the organic compound having an electron transport property includes those having an aromatic ring containing an element having an unshared electron pair, and II: an element having an unshared electron pair being double bond or triple bond. It is preferable to have a polarization between two elements that are bonded to an element and form the bond. By having such a structure, in the structure of the organic compound, it becomes easier to cause a deviation in electron density to an element having an unshared electron pair, and as a result, the structure of the organic compound is more reliably stabilized. .
Specific examples of I include, for example, a compound represented by the following chemical formula 1, or a combination of any two or more thereof. In the compound represented by the following chemical formula 1, Q independently represents N, O, P, S, As, or Se.

Specific examples of II include, for example, compounds represented by the following chemical formula 2 or combinations of any two or more thereof. For example, as a combination of Q ₁ and Q ₂ , double bonds such as C = O, N = O, P = O, S = O, Se = O, C = S, P = S, and C≡N Triple bond and the like. Here, it for Q ₁ than Q ₂ is to be bond order often. Therefore, Q ₁ is bonded to an element other than Q ₂ or a group such as a phenyl group or an alkyl group.

Moreover, the organic compound may have both I and II.
As an organic compound which has the above characteristics and is excellent in electron transport ability, the compound shown to following Chemical formula 3-10, or its derivative (s) is mentioned, for example. The electron transport layer 6 containing these organic compounds as a main material and in which metal ions from the cathode 8 are diffused has particularly excellent electron transport efficiency and durability.

  On the other hand, as the metal ions, at least one of alkali metal ions, alkaline earth metal ions, and rare earth metal ions may be appropriately selected according to the type of organic compound. Specifically, for example, when the condensed heterocyclic compound represented by the chemical formula 4 or a derivative thereof is used as the organic compound, a metal ion such as Li, Cs, Ca, Mg, or Yb is preferable. Selected.

Further, the concentration gradient of the metal ions in the electron transport layer 6 is slightly different depending on the type of the organic compound having electron transport properties, but is preferably set to the following concentration.
That is, the total thickness of the electron transport layer 6 is D, and from the total number of elements having an unshared electron pair contained in the organic compound, the number of bonds in which elements having an unshared electron pair are double-bonded or triple-bonded to each other. When the number excluding A is A [pieces] and the number of metal ions is B [pieces], B / A is 0.2 or more at a thickness of D × 1/5 from the interface with the cathode 8. Is more preferable, and about 0.2 to 0.5 is more preferable. By setting the size of B / A within the above range in the thickness of D × 1/5, metal ions can be present in excess or deficiency with respect to the organic compound, and the structure of the organic compound is more reliably stabilized. Can be made. Further, the efficiency of electron injection from the cathode 8 to the electron transport layer 6 by the action of metal ions can be sufficiently improved. For this reason, the characteristics of the electron transport layer 6 can be further improved.

  Further, in the thickness of D × 2/3 from the interface with the cathode 8, B / A is preferably 0.1 or less, and more preferably about 0.01 to 0.05. By setting the size of B / A in the above range in the thickness of D × 2/3, the number of metal ions that do not cause a chemical interaction with the organic compound in the electron transport layer 6 is sufficiently increased. In addition, the metal ions can be substantially absent near the interface between the electron transport layer 6 and the light emitting layer 5, and the metal ions contained in the electron transport layer 6 diffuse into the light emitting layer 5. Can be reliably prevented. As a result, it is possible to suitably prevent a decrease in the light emission luminance of the light emitting element 1 with the lapse of time and repetition of voltage application.

Although the average thickness of the electron carrying layer 6 is not specifically limited, It is preferable about 1-100 nm, and it is more preferable that it is about 20-50 nm.
The electron transport layer 6 is not limited to a single layer as described above, but may be a layered body. In this case, the layer in contact with the cathode 8 has the configuration described above as the electron transport layer 6, and the other layers only have to be composed of an organic material having electron transport properties.

The organic material having an electron transporting property is not particularly limited, and examples thereof include 1,3,5-tris [(3-phenyl-6-tri-fluoromethyl) quinoxalin-2-yl] benzene (TPQ1). Benzene compounds (starburst compounds), naphthalene compounds such as naphthalene, phenanthrene compounds such as phenanthrene, chrysene compounds such as chrysene, and complexes containing 8-hydroxyquinoline aluminum (Alq ₃ ) as a ligand And various metal complexes.

When energization (voltage is applied) between the anode 3 and the cathode 8, holes move in the hole transport layer 4 and electrons move in the electron transport layer 6. Will recombine. And in the light emitting layer 5, an exciton (exciton) produces | generates, and when this exciton returns to a ground state, energy (fluorescence and phosphorescence) is discharge | released (light emission).
As a constituent material (light emitting material) of the light emitting layer 5, various polymer materials and various low molecular materials can be used alone or in combination.

  Examples of the polymer light-emitting material include polyacetylene compounds such as trans-type polyacetylene, polyparaphenylene vinylene compounds such as poly (para-phenvinylene) (PPV), and poly (3-alkylthiophene) (PAT). And a polyfluorene compound such as poly (9,9-dialkylfluorene) (PDAF).

On the other hand, examples of low-molecular light-emitting materials include benzene compounds such as distyrylbenzene (DSB), naphthalene compounds such as naphthalene, phenanthrene compounds such as phenanthrene, and chrysene compounds such as 6-nitrochrysene. Compounds and the like.
Although the average thickness of the light emitting layer 5 is not specifically limited, It is preferable that it is about 10-150 nm, and it is more preferable that it is about 50-100 nm.

Next, the manufacturing method of the light emitting device of the present invention will be described by taking as an example the case of manufacturing the display device 10 described above.
The display device 10 of the present embodiment includes a first laminate 101 in which a cathode 8 is formed on an upper substrate 9, and an anode 3, a hole transport layer 4, a light emitting layer 5, and an electron transport layer on a TFT circuit substrate 20. 6 is sequentially bonded to the second laminated body 102 in which 6 is formed.

Hereinafter, a method for manufacturing the display device 10 (a method for manufacturing a light emitting device of the present invention) will be described in detail.
[1] Manufacturing process of first stacked body and second stacked body [1-1] Manufacturing process of first stacked body (first process)
A: First, an upper substrate 9 is prepared, and a cathode 8 is formed on the upper substrate 9.
In this step A, first, a cathode forming material (liquid material) containing the conductive polymer material and metal ions as described above is prepared. This is because the conductive polymer material is dissolved or dispersed in a solvent or dispersion medium, and the solvent or dispersion medium containing the conductive polymer material is dissolved in at least one of alkali metal, alkaline earth metal, and rare earth metal. The metal compound can be dissolved, and the metal ion can be dissociated from the metal compound.

  Alternatively, a solution or dispersion containing a conductive polymer material and a solution containing metal ions may be prepared separately and then mixed. At this time, the solvent or dispersion medium used for each solution or dispersion may be different as long as they are not separated and can be mixed. This makes it possible to prepare a cathode-forming material even when the solubility of the conductive polymer material and the metal compound in a single solvent or dispersion medium is significantly different and mixing at a desired quantity ratio is difficult. Become.

  Examples of the metal compound include inorganic acid salts such as carbonate, nitrate and sulfate, salts such as organic acid salts such as acetate and acetyl acetate, halides such as chloride and bromide, methoxide and ethoxide. Examples of such alkoxides and metal complexes having an easily detachable ligand such as acetylacetonate can be given, and those containing at least one of a metal salt and a metal complex as a main component are preferable. Since these metal compounds are relatively stable in the air, they are easy to handle and are preferable because they easily dissociate metal ions.

  As the solvent or dispersion medium used for preparing the cathode forming material, when the metal compound is directly dissolved in the dispersion medium in which the conductive polymer material is dissolved or dispersed, the solvent easily dissolves the metal compound. It is preferable to dissolve and dissociate metal ions. In addition, when the conductive polymer material solution or dispersion and the metal compound solution are prepared separately, the solvent used for the metal compound solution easily dissolves the metal compound and dissociates the metal ions. It is preferable that

As such a solvent, a protic polar solvent is preferably used.
Examples of the protic polar solvent include water, methanol, ethanol, propanol, butanol, benzyl alcohol, monovalent alcohols such as diethylene glycol monomethyl ether, alcohols such as polyhydric alcohols such as ethylene glycol and glycerin, acetic acid, formic acid, ( Carboxylic acids such as (meth) acrylic acid, amines such as ethylenediamine and diethylamine, formamide, amides such as N, N-dimethylformamide, phenols, phenols such as p-butylphenol, acetylacetone, diethyl malonate Such active methylene compounds and the like can be mentioned, and one or more of these can be used in combination.

  Especially, as a protic polar solvent, what has at least 1 sort (s) of water and alcohol as a main component is preferable. Since water and alcohols have high solubility of metal compounds, the use of a protic polar solvent that contains at least one of water and alcohols as a main component ensures that metal ions are extracted from the metal compounds. It can be dissociated and the preparation of the cathode forming material becomes easy.

In particular, the alcohol is preferably a monohydric alcohol having 1 to 7 carbon atoms (preferably 1 to 4 carbon atoms). Such a monohydric alcohol having a carbon number has high solubility of the metal compound.
For example, when cesium carbonate (Cs ₂ CO ₃ ) is dissolved as a metal compound in monohydric alcohol (R—OH), Cs ions (metal ions) are dissociated by the following reaction.
Cs ₂ CO ₃ + 2ROH → 2Cs (OR) + CO ₂ + H ₂ O
Cs (OR) + H ₂ O → Cs ⁺ + OH ⁻ + ROH

Next, after the prepared cathode forming material is supplied onto the upper substrate 9, a film is formed by drying (desolvation), and then, if necessary, post-treatment (for example, baking by heating, Heating below the firing temperature, infrared irradiation, application of ultrasonic waves, etc.). Thereby, the cathode 8 is obtained on the upper substrate 9.
Examples of the method for supplying the cathode forming material include spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen. Various coating methods such as a printing method, a flexographic printing method, an offset printing method, and an inkjet printing method can be used. By using such a coating method, the cathode can be formed relatively easily.

The drying can be performed, for example, by standing in an atmospheric pressure or a reduced pressure atmosphere, heat treatment, or blowing an inert gas.
The metal ion concentration of the cathode 8 formed in this step is such that the metal ions contained in the cathode 8 can diffuse into the electron transport layer 6 with the appropriate concentration gradient described above in the subsequent step [2]. Is set as follows. Specifically, although it varies slightly depending on the types of conductive polymer material, metal ions and organic compounds, bonding conditions, etc., it is preferably about 0.1 to 50.0 wt%, and 1.0 to 20. More preferably, it is about 0 wt%. Thereby, the metal ion contained in the cathode 8 can be reliably diffused in the electron transport layer 6 so as to have the above-described appropriate concentration gradient.

Prior to this step, the upper surface of the upper substrate 9 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart lyophilicity to the upper surface of the upper substrate 9 and to remove (clean) organic substances adhering to the upper surface of the upper substrate 9.
Here, the oxygen plasma treatment conditions include, for example, a plasma power of about 100 to 800 W, an oxygen gas flow rate of about 50 to 100 mL / min, a conveyance speed of the member to be treated (anode 3) of about 0.5 to 10 mm / sec, The temperature of the substrate 9 is preferably about 70 to 90 ° C.
As described above, the first laminated body 101 in which the cathode 8 is formed on the upper substrate 9 is obtained.

[1-2] Manufacturing process of second laminated body (second process)
B: First, a substrate 21 is prepared, and silicon oxide having an average thickness of about 200 to 500 nm is formed on the substrate 21 by, for example, plasma CVD using TEOS (tetraethoxysilane) or oxygen gas as a source gas. A base protective layer 23 configured as a main material is formed.
C: Next, the driving TFT 24 is formed on the base protective layer 23.
First, in a state where the substrate 21 is heated to about 350 ° C., a semiconductor film composed mainly of amorphous silicon having an average thickness of about 30 to 70 nm is formed on the base protective layer 23 by, for example, plasma CVD. To do.

Next, the semiconductor film is crystallized by laser annealing, solid phase growth, or the like to change 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. As for the line beam, the line beam is scanned so that a portion corresponding to 90% of the peak value of the laser intensity in the short dimension direction overlaps each region.

  Next, the semiconductor film is patterned to form islands, and an average thickness is formed by, for example, plasma CVD using TEOS (tetraethoxysilane) or oxygen gas as a source gas so as to cover each island-shaped semiconductor film 241. A gate insulating layer 242 composed mainly of silicon oxide or silicon nitride having a thickness of about 60 to 150 nm is formed.

Next, a conductive film composed mainly of a metal such as aluminum, tantalum, molybdenum, titanium, or tungsten is formed on the gate insulating layer by, for example, sputtering, and then patterned to form the gate electrode 243. .
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.

D: Next, the source electrode 244 and the drain electrode 245 that are electrically connected to the driving TFT 24 are formed.
First, after forming the first interlayer insulating layer 25 so as to cover the gate electrode 243, a contact hole is formed.
Next, a source electrode 244 and a drain electrode 245 are formed in the contact hole.

E: Next, a wiring (relay electrode) 27 that electrically connects the drain electrode 245 and the anode 3 is formed.
First, the second interlayer insulating layer 26 is formed on the first interlayer insulating layer 25, and then contact holes are formed.
Next, a wiring 27 is formed in the contact hole.

F: Next, the anode (pixel electrode) 3 is formed on the second interlayer insulating layer 26 so as to be in contact with the wiring 27.
The anode 3 can be formed in the same manner as the gate electrode 243.
G: Next, a partition wall 31 is formed on the second interlayer insulating layer 26 so as to partition each anode 3.

The partition wall 31 can be formed by patterning after forming an insulating film.
The constituent material of the insulating film (partition wall 31) is selected in consideration of heat resistance, liquid repellency, ink solvent resistance, adhesion to the underlayer, and the like.
Examples of such materials include organic materials such as acrylic resins and polyimide resins, and inorganic materials such as SiO ₂ .

In particular, when the anode 3 is composed of an oxide material as a main material, it is preferable to use SiO ₂ as a constituent material of the partition wall 31. Thereby, the adhesiveness of the anode 3 and the partition part 31 can be improved.
Moreover, the partition part 31 which shows liquid repellency can be obtained, for example by forming using a fluorine-type resin, or performing the fluorine plasma process to the surface of the partition part 31.

Further, the shape of the opening of the partition wall 31 may be any shape such as, for example, a circle, an ellipse, a quadrangle, or a polygon such as a hexagon.
In addition, when making the shape of opening of the partition part 31 into a polygon, it is preferable that the corner | angular part is roundish. Thus, when the hole transport layer 4, the light emitting layer 5, and the electron transport layer 6 are formed using a liquid material, the liquid material is reliably supplied to every corner of the space inside the partition wall 31. can do.
The height of the partition wall 31 is appropriately set according to the total thickness of the hole transport layer 4, the light emitting layer 5, and the electron transport layer 6, and is not particularly limited, but is about 1 to 2 μm. preferable. By setting it as such a height, the function as a partition is fully exhibited.

H: Next, a hole transport layer 4 is formed on each anode 3.
The hole transport layer 4 may be formed by, for example, a vapor phase process using a sputtering method, a vacuum deposition method, a CVD method, a spin coating method (virosol method), a screen printing method, a flexographic printing method, an offset printing method, an inkjet printing method. It can be formed by a liquid phase process using a method or the like.
These methods are selected in consideration of the physical stability and / or chemical characteristics such as the thermal stability of the constituent material of the hole transport layer and the solubility in a solvent.

Among these methods, it is preferable to form by a liquid phase process using an inkjet method (droplet discharge method). By using the inkjet method, the hole transport layer 4 can be made thinner and the pixel size can be reduced. In addition, since the liquid material for forming the hole transport layer can be selectively supplied to the inside of the partition wall 31, waste of the liquid material can be omitted.
Specifically, the liquid material for forming the hole transport layer is ejected from the head of the ink jet printing apparatus, supplied onto each anode 3, dried (desolvent or dedispersion medium), and if necessary, A short heat treatment is performed at about 150 ° C.

The liquid material to be used is prepared by dissolving or dispersing the hole transport material as described above in a solvent or a dispersion medium.
Examples of the solvent or dispersion medium used for preparing the liquid material include various inorganic solvents such as ammonia, hydrogen peroxide, water, and carbon disulfide, ketone solvents such as methyl ethyl ketone (MEK) and acetone, ethanol, and ethylene. Alcohol solvents such as glycol, ether solvents such as diethyl ether and diethylene glycol ethyl ether (carbitol), cellosolve solvents such as methyl cellosolve, aliphatic hydrocarbon solvents such as hexane and cyclohexane, toluene, xylene, benzene, etc. Aromatic hydrocarbon solvents, aromatic heterocyclic compounds such as pyridine and methylpyrrolidone, amide solvents such as N, N-dimethylformamide (DMF), halogen compounds such as dichloromethane, esters such as ethyl formate Solvent, dimethyl sulfoxide (DM O), sulfur compound-based solvents such as sulfolane, nitrile solvents such as acetonitrile, formic acid, various organic solvents such as an organic acid solvents such as trifluoroacetic acid, or mixed solvents containing them.

The liquid material supplied onto the anode 3 has high fluidity (low viscosity) and tends to spread in the horizontal direction (surface direction). However, since the anode 3 is surrounded by the partition wall 31, the liquid material is predetermined. Spreading outside the region is prevented, and the contour shape of the hole transport layer 4 (light emitting element 1) is accurately defined.
The drying method is the same as that described in the cathode forming step.

Prior to this step, the upper surface of the anode 3 may be subjected to oxygen plasma treatment. Thereby, it is possible to impart lyophilicity to the upper surface of the anode 3 and to remove (clean) organic substances adhering to the upper surface of the anode 3.
Here, the conditions for the oxygen plasma treatment are the same as in the case where the upper substrate 9 is subjected to the oxygen plasma treatment.

I: Next, the light emitting layer 5 is formed on each hole transport layer 4 (on the side opposite to the TFT circuit substrate 20 of the anode 3).
The light emitting layer 5 can also be formed by a gas phase process or a liquid phase process, but for the same reason as described above, it is preferable to form the light emitting layer 5 by a liquid phase process using an ink jet method (droplet discharge method). . In addition, when the multi-color light emitting layer 5 is provided by using the inkjet method, there is an advantage that the pattern can be easily applied for each color.

J: Next, the electron transport layer 6 is formed on the light emitting layer 5 so as to cover each light emitting layer 5 and each partition wall 31.
The electron transport layer 6 can also be formed by a gas phase process or a liquid phase process. However, for the same reason as described above, the electron transport layer 6 may be formed by a liquid phase process using an ink jet method (droplet discharge method). preferable.

In addition, as a solvent used for preparation of the electron transport layer forming material supplied on the light emitting layer 5, it is preferable that the light emitting layer 5 is hard to swell or melt | dissolve. Thereby, it is possible to prevent the light emitting material from being altered or deteriorated, or the light emitting layer 5 from being dissolved and the film thickness from being extremely reduced. As a result, it is possible to prevent a decrease in the light emission efficiency of the light emitting element 1.
As described above, the second laminate in which the anode 3, the hole transport layer 4, the light emitting layer 5, and the electron transport layer 6 are formed (laminated) in this order on the TFT circuit substrate 20 from the TFT circuit substrate 20 side. A body 102 is obtained.

[2] Joining step (third step) between the first laminate and the second laminate
Next, the first stacked body 101 and the second stacked body 102 are joined.
First, the first stacked body 101 and the second stacked body 102 are aligned so that alignment marks (not shown) formed in advance coincide with each other, and at one end side (the right side in FIG. 2), the first stacked body 101 and the second stacked body 102 are aligned. The lower surface of the stacked body 101 and the upper surface of the second stacked body 102 are brought into contact with each other.

  Next, in this state, the first stacked body 101 and the second stacked body 102 are bonded to the lower surface of the first stacked body 101 (the surface opposite to the upper substrate side of the cathode) and the second stacked body 102. At the place where the upper surface (the surface opposite to the light emitting layer side of the electron transport layer) is in contact, it is installed in the joining device so as to be sandwiched between the pair of rollers 900a and 900b. Thereby, the 1st laminated body 101 (upper board | substrate 9) and the 2nd laminated body 102 (board | substrate 21) are pressurized.

At this time, the other end portion of the first laminated body 101 is fixed to a support portion 910 provided so as to be movable above the roller 900a of the joining device. Thereby, the 1st laminated body 101 is installed (set) in a joining apparatus in the bent state.
Each of the rollers 900a and 900b is provided with a heating unit (not shown) such as a heater, and the first laminated body 101 and the second laminated body 102 are sandwiched between a pair of rollers 900a and 900b. The heated part is heated.

Next, as shown in FIGS. 2B and 2C, the rollers 900a and 900b are moved toward the other end side (left side in FIG. 2).
Thereby, the electron transport layer 6 and the cathode 8 are sequentially joined at the portion sandwiched between the pair of rollers 900a and 900b, and a joined body is obtained.
According to such a bonding method, the first stacked body 101 is bonded to the second stacked body 102 in order from one end side to the other end side, so that the electron transport layer 6 and the cathode 8 are Air can be excluded from the boundary, and bubbles can be prevented from remaining at these interfaces. As a result, the adhesion near the interface between the electron transport layer 6 and the cathode 8 can be improved. In addition, strain stress and thermal damage generated at the interface can be reduced.

Further, since the cathode 8 is mainly composed of a conductive polymer material, the surface of the cathode 8 can be a flat surface. As a result, the electron transport layer 6 and the cathode 8 are brought into contact with each other, When these are joined, it is possible to reliably prevent pinholes from occurring in the electron transport layer 6.
Further, in this bonding step, the cathode 8 and the electron transport layer 6 are bonded to each other by the bonding method as described above, so that the metal ions contained in the cathode 8 cross the interface with the electron transport layer 6 and the electron transport layer. 6 diffuses into. As a result, the metal transport layer 6 contains metal ions with a concentration gradient that decreases in concentration from the cathode 8 side toward the light emitting layer 5 side.

In this bonding step, the bonding state between the electron transport layer 6 and the cathode 8 and the diffusion amount of metal ions from the cathode 8 to the electron transport layer 6 are determined depending on the heating temperature, the pressure applied, and the electron transport layer 6 and the cathode. 8 is controlled by the speed of joining.
The heating temperature is preferably the softening point temperature (glass transition temperature) of the electron transport layer 6 or the cathode 8 having a lower softening point temperature, or a temperature slightly lower than that. Although it varies slightly depending on the constituent material of the layer and is not particularly limited, it is preferably about 40 to 120 ° C, more preferably about 60 to 100 ° C. If the heating temperature is too low, the electron transport layer 6 and the cathode 8 may not be sufficiently joined, and the diffusion amount of metal ions from the cathode 8 to the electron transport layer 6 may be insufficient. On the other hand, if the heating temperature is too high, each layer may be altered or deteriorated.

At this time, it is preferable that the layer having a low softening point temperature, that is, the layer whose temperature is lower than or equal to the softening point temperature in this step, is the cathode 8. Thereby, the metal ion contained in the cathode 8 can be efficiently diffused in the electron transport layer 6.
The pressure of the pressure at this time, varies slightly depending on the temperature or the like of the heating is not particularly limited, and is preferably about ^{0.1~10kgf / cm 2, 0.2~5kgf / cm} 2 of about It is more preferable that If the pressure of the pressurization is too small, there is a possibility that the electron transport layer 6 and the cathode 8 cannot be sufficiently joined, and the diffusion amount of metal ions from the cathode 8 to the electron transport layer 6 may be insufficient. . On the other hand, even if the pressure of the pressurization is increased beyond the upper limit, an increase in the effect commensurate with increasing the pressure cannot be expected.

  Further, the speed at which the electron transport layer 6 and the cathode 8 are joined, that is, the moving speed of the rollers 900a and 900b is not particularly limited, but is preferably about 5 to 50 mm / second, and about 10 to 40 mm / second. It is more preferable that Thereby, the electron transport layer 6 and the cathode 8 can be reliably joined, and the diffusion of metal ions from the cathode 8 to the electron transport layer 6 can be performed reliably.

  Further, in this joining step, the first laminated body 101 and the second laminated body 102 are heated or pressurized simultaneously with or immediately after the first laminated body 101 and the second laminated body 102. It is also possible to promote diffusion of metal ions from the cathode 8 to the electron transport layer 6 by applying a predetermined treatment to at least one of them. Thereby, the amount of diffusion of metal ions into the electron transport layer 6 can be increased, and by appropriately setting processing conditions such as the processing time of the predetermined processing, the cathode 8 can transfer to the electron transport layer 6. The amount of diffusion of metal ions can be easily controlled.

  Such a predetermined treatment is not particularly limited. For example, a method of generating an electric field inside the electron transport layer 6 and the cathode 8 by applying a voltage between the anode 3 and the cathode 8, For example, a method of vibrating at least one of the first stacked body 101 and the second stacked body 102 may be used. According to these methods, the diffusion amount of metal ions into the electron transport layer 6 can be reliably increased with a relatively simple configuration, and the diffusion amount of metal ions into the electron transport layer 6 can be easily controlled. can do.

These methods may be used alone or in combination.
In addition, in the method of applying a voltage, it is preferable that the voltage applied between the anode 3 and the cathode 8 is about 1-50V, and it is more preferable that it is about 5-15V. If the voltage is too lower than the lower limit, the effect of promoting the diffusion of metal ions into the electron transport layer 6 may not be sufficiently obtained. Further, if the voltage is too higher than the upper limit value, there is a risk of adversely affecting each layer constituting the first stacked body 101 and the second stacked body 102.

In the method of vibrating at least one of the laminates, the vibration frequency is preferably about 1 to 1 × 10 ⁴ kHz, more preferably about 10 to 1 × 10 ² kHz. When the frequency is lower than the above range, the effect of promoting the diffusion of metal ions into the electron transport layer 6 may not be sufficiently obtained. Even if the frequency is increased beyond the above range, no further increase in effect can be expected.

[3] Heat treatment step Next, heat treatment (post-bake treatment) is performed on the obtained bonded body as necessary.
Thereby, even when an internal stress is generated in the first stacked body 101 and the second stacked body 102 when the first stacked body 101 and the second stacked body 102 are joined, the internal stress is relieved. It is possible to prevent peeling easily at the interface between the layers.

The heating temperature at this time is preferably set to a temperature lower than the glass transition temperature of the constituent material having the lowest glass transition temperature among the constituent materials of the organic layer provided in the joined body. Thereby, it is possible to surely relieve internal stress while preventing thermal damage to each layer.
In addition, the heating time at this time is slightly different depending on the heating temperature and the like, but is preferably about 10 to 120 minutes, and more preferably about 30 to 90 minutes. Thereby, it is possible to surely relieve internal stress while preventing thermal damage to each layer.

In addition, this process [3] is abbreviate | omitted and the obtained joined body can also be made into a finished product as it is.
As described above, in the method for manufacturing a light emitting device of the present invention, the display device 10 can be manufactured with a relatively simple configuration in which the first stacked body 101 and the second stacked body 102 are joined.
Further, the metal ions in the cathode 8 diffuse into the electron transport layer 6 in the bonding step between these bonded bodies. As a result, the electron transport layer 6 is in a state in which metal ions are contained with a concentration gradient such that the concentration decreases from the cathode 8 side toward the light emitting layer 5 side.

As described above, the electron transport layer 6 is configured to include a metal ion in addition to an electron transporting organic compound (an organic compound having a function of transporting electrons), so that the electron transport layer 6 has excellent electron transport. Demonstrate sex. Thereby, even if the voltage applied between the anode 3 and the cathode 8 is relatively low, the display device 10 can efficiently inject electrons into the light emitting layer 5 and obtain high luminance.
Since the metal ions are contained in the electron transport layer 6 with a concentration gradient that decreases from the cathode 8 side toward the light emitting layer 5 side as described above, The transport layer 6 can also function as a barrier layer that prevents the metal ions and the light-emitting material contained in the light-emitting layer 5 from coming into contact with each other. As a result, diffusion of metal ions contained in the electron transport layer 6 into the light emitting layer 5 can be prevented or suppressed, and the light emitting element 1 (display device 10) can have excellent durability. .

<Electronic equipment>
Such a display device (light emitting device of the present invention) 10 can be incorporated into various electronic devices.
FIG. 3 is a perspective view showing the configuration of a mobile (or notebook) personal computer to which the electronic apparatus of the present invention is applied.

In this figure, a personal computer 1100 includes a main body 1104 provided with a keyboard 1102 and a display unit 1106 provided with a display. The display unit 1106 is rotatable with respect to the main body 1104 via a hinge structure. It is supported by.
In the personal computer 1100, the display unit included in the display unit 1106 is configured by the display device 10 described above.

FIG. 4 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the present invention is applied.
In this figure, a cellular phone 1200 includes a plurality of operation buttons 1202, an earpiece 1204 and a mouthpiece 1206, and a display unit.
In the mobile phone 1200, the display unit is configured by the display device 10 described above.

FIG. 5 is a perspective view showing a configuration of a digital still camera to which the electronic apparatus of the present invention is applied. In this figure, connection with an external device is also simply shown.
Here, an ordinary camera sensitizes a silver halide photographic film with a light image of a subject, whereas a digital still camera 1300 photoelectrically converts a light image of a subject with an imaging device such as a CCD (Charge Coupled Device). An imaging signal (image signal) is generated.

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

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

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

The electronic apparatus of the present invention includes, for example, a television, a video camera, a viewfinder type, in addition to the personal computer (mobile personal computer) in FIG. 3, the mobile phone in FIG. 4, and the digital still camera in FIG. Monitor direct-view video tape recorder, laptop personal computer, car navigation system, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, workstation, video phone, security TV Monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and automatic ticket vending machines for financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiographs, ultrasound diagnostic devices, internal Endoscope display device), fish finder, various measuring instruments, Vessels such (e.g., gages for vehicles, aircraft, and ships), a flight simulator, various monitors, and a projection display such as a projector.
As mentioned above, although the manufacturing method of the light-emitting device of this invention, the light-emitting device, and the electronic device were demonstrated based on embodiment of illustration, this invention is not limited to these.

Next, specific examples of the present invention will be described.
1. Manufacture of Display Devices In each of the following examples and comparative examples, 10 display devices were manufactured.
(Example 1)
<1> First, a polycarbonate film substrate having an average thickness of 1 mm was prepared, immersed in order of acetone and 2-propanol, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.

<2> Next, a polypyrrole dispersion was prepared, and an aqueous solution of cesium carbonate (Cs ₂ CO ₃ ) as a metal compound was prepared. And this dispersion liquid and aqueous solution were mixed so that the density | concentration of the metal ion contained in the cathode formed at the following process <3> might be 50.0 wt%. Thereby, a cathode forming material was obtained.
<3> The prepared cathode forming material was applied on a substrate by a spin coating method, and then annealed on a hot plate at 130 ° C. for 10 minutes. Thereby, a cathode having an average thickness of 10 nm was formed on the substrate.
The first laminate was manufactured through the above steps.

<4> Next, a transparent glass substrate having an average thickness of 5 mm was prepared, and a circuit portion was formed on the glass substrate as described above.
<5> Next, after an ITO film having an average thickness of 150 nm was formed on the circuit portion by vacuum deposition, patterning was performed using a photolithography method and an etching method to obtain an anode (pixel electrode). . At this time, an alignment mark was formed.
And the board | substrate with which this circuit part and the anode were formed was immersed in order of acetone and 2-propanol, and after performing ultrasonic cleaning, the oxygen plasma process was performed.

<6> Next, after applying polyimide (insulating photosensitive resin) so as to cover the edge portion of each anode, a partition wall portion was formed by exposure.
<7> Next, an aqueous dispersion of poly (3,4-ethylenedioxythiophene / styrene sulfonic acid) (PEDOT / PSS) is supplied to the inside of the partition wall portion by an inkjet method, and then on a hot plate. Annealing was performed at 200 ° C. for 10 minutes under atmospheric pressure. Thereby, a hole transport layer having an average thickness of 60 nm was formed on the anode layer.

<8> Next, a xylene solution in which polydioctylfluorene, dioctylfluorene and an alternating copolymer of benzothiadiazole (F8BT) were dissolved was supplied to the inside of the partition wall portion by an inkjet method, and then dried. This formed the light emitting layer with an average thickness of 70 nm on the positive hole transport layer.
<9> Next, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (an organic compound represented by the following chemical formula 11) is dissolved in N, N-dimethylformamide to form an electron transport layer forming material. Was prepared. And after supplying this electron transport layer forming material on a light emitting layer and a partition part by a spin coat method, annealing treatment was performed on a hot plate at 130 ° C. for 10 minutes. This formed the electron carrying layer on the light emitting layer and the partition part.

Through the above steps, a second laminate was produced.
<10> Next, the electron transport layer and the cathode are brought into contact at one end side, and these are joined in order toward the other end side as shown in FIG. A joined body was obtained and used as a finished product of the display device.
The conditions at this time were heating temperature: 150 ° C., pressurizing pressure: 1 kgf / cm ² , and roller moving speed: 10 mm / sec.
Moreover, this joining was performed in the state which pressed the other end part of the polycarbonate film substrate toward the one end side with the support part.
Through the above process, a display device was manufactured.

(Example 2)
In the step <10>, a voltage of 6 V is applied in the thickness direction of the first stacked body and the second stacked body by the electrodes disposed inside the pair of rolls, and the first stacked body and the first stacked body A display device was manufactured in the same manner as in Example 1 except that the laminated body 2 was joined.
(Example 3)
Example 1 except that in the step <10>, the first laminated body and the second laminated body were joined to the first laminated body and the second laminated body while applying vibration of a frequency of 50 kHz. In the same manner as in Example 1, a display device was manufactured.

Example 4
In the above step <9>, the examples described above were used except that an N, N-dimethylformamide solution of 1,1′-thiocarbonyldiimidazole (organic compound shown in the following chemical formula 6) was used as the electron transport layer forming material. In the same manner as in Example 1, a display device was manufactured.
(Example 5)
A display device was manufactured in the same manner as in Example 1 except that in the step <2>, ytterbium chloride (YbCl ₃ ) was used as the metal compound used in preparing the cathode forming material.
(Example 6)
In the step <2>, in the same manner as in Example 1 except that polyparaphenylene vinylene was used instead of polypyrrole as the conductive polymer material used in preparing the cathode forming material, the display device was Manufactured.

(Comparative Example 1)
A display device was manufactured in the same manner as in Example 1 except that, in the step <2>, the cathode forming material was prepared without mixing the metal compound.
(Comparative Example 2)
In the step <2>, a cathode forming material is prepared without mixing a metal compound. In the step <9>, the electron transport layer forming material is a metal other than the organic compound shown in the chemical formula 11 above. A display device was manufactured in the same manner as in Example 1 except that cesium carbonate (Cs ₂ CO ₃ ) was added as a compound.

(Comparative Example 3)
A light emitting device was manufactured in the same manner as in Example 1 except that in steps <1> to <3>, the cathode was formed as follows.
First, a polycarbonate film substrate having an average thickness of 1 mm was prepared, immersed in acetone and 2-propanol in this order, subjected to ultrasonic cleaning, and then subjected to oxygen plasma treatment.
A cathode was obtained by forming an Al layer with an average thickness of 200 nm and an Al layer with an average thickness of 1500 nm on this substrate by vacuum deposition.

2. Evaluation 2-1. Confirmation of the presence of metal ions For the display devices produced in each Example, the presence of metal ions present in the electron transport layer was confirmed by secondary ion mass spectrometry (SIMS method).
The secondary ion mass spectrometry was performed using a SIMS device (Physical Electronics, “ADEPT1010”).

As a result, it was confirmed that metal ions were present in the electron transport layer in each example, and the metal ions were diffused from the cathode.
Furthermore, in each Example, it has confirmed that this metal ion was unevenly distributed in the contact surface side with a cathode, and did not exist in the contact surface side with a light emitting layer. Thereby, it has confirmed that the electron carrying layer was functioning also as a barrier layer which prevents a metal ion from contacting a light emitting layer.

2-2. Evaluation of Luminous Efficiency For the display devices manufactured in each Example and Comparative Example, the luminance value (cd / m ²⁾ was measured by measuring the current value and luminance when a voltage of 10 V was applied between the anode and the cathode. )
2-3. Evaluation of Durability For the display devices manufactured in each Example and each Comparative Example, a voltage of 25 V was repeatedly applied 100 times between the anode and the cathode, and then the occurrence of a short circuit was examined. For the display device in which no short circuit occurred, the light emission luminance (cd / m ² ) when a voltage of 10 V was applied was determined in the same manner as in 2-2.
The evaluation results of 2-2 (evaluation of luminous efficiency) and 2-3 (evaluation of durability) are shown in Table 1 below.

In Table 1, as the relative value for each evaluation result, the emission luminance (cd / m ² ) measured in Comparative Example 1 of 2-2 (emission efficiency evaluation) is “1”. Indicated.
As shown in Table 1, all the display devices manufactured in each example were able to obtain high luminance in 2-2 (evaluation of luminous efficiency). Further, as shown in 2-3 (evaluation of durability), even after a high voltage was repeatedly applied, no short circuit occurred, high luminance was maintained, and the durability was excellent.

On the other hand, the display device manufactured by omitting the addition of the metal compound to the cathode as in Comparative Example 1 was excellent in durability but could not obtain high luminance.
In addition, the display device manufactured by adding a metal compound directly to the electron transport layer as in Comparative Example 2 can obtain high brightness at the initial stage, but the brightness is significantly reduced by repeated application of high voltage. It was inferior in durability.
Further, the display device manufactured by forming the cathode with a metal film as in Comparative Example 3 can obtain high brightness at the initial stage, but short-circuiting occurs due to repeated application of a high voltage, so brightness measurement is not possible. It became possible and was inferior in durability.

It is a longitudinal cross-sectional view which shows embodiment of the active matrix type display apparatus to which the light-emitting device of this invention is applied. It is a figure for demonstrating the manufacturing method of the active matrix type display apparatus shown in FIG. 1 is a perspective view showing a configuration of a mobile (or notebook) personal computer to which an electronic apparatus of the present invention is applied. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) to which the electronic device of this invention is applied. It is a perspective view which shows the structure of the digital still camera to which the electronic device of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Light emitting element 3 ... Anode 4 ... Hole transport layer 5 ... Light emitting layer 6 ... Electron transport layer 8 ... Cathode 9 ... Upper substrate 10 ... Display apparatus 20 ... TFT circuit board 21 ... Substrate 22 …… Circuit part 23 …… Base protective layer 24 …… Drive TFT 241 …… Semiconductor layer 242 …… Gate insulating layer 243 …… Gate electrode 244 …… Source electrode 245 …… Drain electrode 25 …… First layer Insulating layer 26 …… Second interlayer insulating layer 27 …… Wiring 31 …… Partition wall portion 101 …… First laminated body 102 …… Second laminated body 900a, 900b …… Roller 910 …… Supporting portion 1100 …… Personal Computer 1102 ... Keyboard 1104 ... Main body 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation buttons 1204 ... Earpiece 1206 ... Mouthpiece 1300 ... Digital still camera 1302 ... Case (body) 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Circuit board 1312 ... Video signal output terminal 1314 ... Input / output terminal for data communication 1430 ... ... TV monitor 1440 ... Personal computer

Claims (13)

A first step of forming, on a first substrate, a cathode containing at least one metal ion of alkali metal ions, alkaline earth metal ions and rare earth metal ions, and a conductive polymer material;
On the second substrate, at least an anode, a light-emitting layer, and a layer containing an electron-transporting organic compound containing at least one element having an unshared electron pair and having a function of transporting electrons are arranged in this order. And a second step of forming from the second substrate side,
A surface opposite to the first substrate side of the cathode and a surface opposite to the light emitting layer side of the layer having a function of transporting electrons are brought into contact with each other, and the first substrate and the second substrate are brought into contact with each other. By heating and pressurizing the substrate, the cathode and the layer having a function of transporting the electrons are joined, and the metal ions contained in the cathode are diffused into the layer having a function of transporting the electrons. And a third step of manufacturing the light emitting device.   In the third step, the layer having a function of transporting the electrons after being joined to the cathode has a concentration gradient such that the concentration of the metal ions decreases from the cathode side toward the light emitting layer side. The manufacturing method of the light-emitting device of Claim 1 formed by these.   In the third step, at least one of the first substrate and the second substrate at the same time or immediately after heating and pressurizing the first substrate and the second substrate, The method for manufacturing a light-emitting device according to claim 1, wherein diffusion of the metal ions into a layer having a function of transporting the electrons from the cathode is promoted by performing a predetermined treatment.   The method for manufacturing a light-emitting device according to claim 3, wherein diffusion of the metal ions into the layer having a function of transporting electrons is promoted by applying a voltage between the cathode and the anode.   The diffusion of the metal ions into the layer having a function of transporting electrons is promoted by vibrating at least one of the cathode and the layer having a function of transporting electrons. Method for manufacturing the light emitting device.   The method for manufacturing a light-emitting device according to claim 1, wherein the conductive polymer material is composed of a polymer compound containing an ethylenedioxythiophene skeleton.   The light emitting device manufacturing method according to claim 1, wherein the element having an unshared electron pair is at least one of N, O, P, S, As, and Se.   The method for manufacturing a light-emitting device according to claim 1, wherein the electron-transporting organic compound is a condensed heterocyclic compound containing an element having the unshared electron pair or a derivative thereof.   In the electron-transporting organic compound, the element having the unshared electron pair is bonded to another element by a double bond or a triple bond, and the two elements forming the bond have polarization. Item 8. A method for manufacturing a light emitting device according to any one of Items 1 to 7.   In the third step, the layer having a function of transporting the electrons after being joined to the cathode has a thickness of D, and the total number of elements having the unshared electron pairs contained in the organic compound When the number excluding the number of double bonds or triple bonds between the elements is A [pieces] and the number of metal ions is B [pieces], D × 1 from the interface with the cathode The method for manufacturing a light emitting device according to claim 2, wherein B / A is 0.2 or more at a thickness of / 5.   In the third step, the layer having a function of transporting the electrons after being joined to the cathode has a thickness of D, and the total number of elements having the unshared electron pairs contained in the organic compound When the number excluding the number of double bonds or triple bonds between the elements is A [pieces] and the number of the metal ions is B [pieces], D × 2 from the interface with the cathode The method of manufacturing a light emitting device according to claim 2, wherein B / A is 0.1 or less at a thickness of / 3.   A light-emitting device manufactured by the method for manufacturing a light-emitting device according to claim 1.   An electronic apparatus comprising the light emitting device according to claim 12.

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