JP2016195040A - Method of manufacturing light emission device, light emission device and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a light emission device having excellent characteristics, a light emission device, and electronic equipment having the light emission device.SOLUTION: A method of manufacturing a light emitting device comprises a first ink applying step of applying an ink 4a containing a first film forming material to a B pixel region, a first firing step of drying the ink 4a applied to the B pixel region and then baking the ink 4a under an oxygen gas atmosphere to form a hole injection layer 4B, a second ink applying step of applying an ink 4b containing a second film forming material to an RG pixel region, and a second firing step of drying the ink 4b applied to the second pixel region and then baking the ink 4b under an inert gas atmosphere to form hole injection layers 4R, 4G.SELECTED DRAWING: Figure 2

Description

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

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

  For example, when a display device is configured using such light emitting elements, red light emitting elements, green light emitting elements, and blue light emitting elements are used in combination (for example, see Patent Document 1). The light-emitting device described in Patent Document 1 includes a light-emitting element having a red light-emitting layer, a light-emitting element having a green light-emitting layer, and a light-emitting element having a blue light-emitting layer, and the blue light-emitting layer serves as a red light-emitting layer as a common layer. It is also formed on the green light emitting layer. In such a light emitting device, a red light emitting layer and a green light emitting layer are formed by a liquid phase process such as an ink jet method, and a blue light emitting layer and a layer on the cathode side of the blue light emitting layer are used as a common layer by a vapor phase process such as an evaporation method. By forming, efficient production becomes possible.

  However, the light emitting device described in Patent Document 1 has a problem that the characteristics of the hole injection layer of each light emitting element cannot be optimized, and as a result, sufficient characteristics cannot be obtained.

JP 2012-226891 A

  An object of the present invention is to provide a light emitting device manufacturing method and a light emitting device having excellent characteristics, and to provide an electronic apparatus including the light emitting device.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
The method for manufacturing a light emitting device of the present invention includes a first ink application step of applying a first ink containing a first film-forming material to the first pixel region;
A first firing step of forming a first functional layer by drying the first ink applied to the first pixel region, followed by firing in an oxygen gas atmosphere;
A second ink application step of applying a second ink containing a second film-forming material to a second pixel area different from the first pixel area;
A second firing step of forming a second functional layer by drying the second ink applied to the second pixel region and then firing the second ink in an inert gas atmosphere.

  According to such a method for manufacturing a light emitting device, when the first film forming material is a material whose characteristics are improved by oxidation and the second film forming material is a material whose characteristics are deteriorated by oxidation, excellent characteristics are obtained. The 1st functional layer and 2nd functional layer which have can be obtained. Therefore, a light emitting device having excellent characteristics can be manufactured.

[Application Example 2]
In the method for manufacturing a light emitting device of the present invention, it is preferable that each of the first functional layer and the second functional layer is a hole injection layer.

  As a result, a hole injection layer that exhibits superior characteristics by oxidation can be formed in the first pixel area, and a hole injection layer that exhibits superior characteristics by reducing oxidation can be formed in the second pixel area. .

[Application Example 3]
In the manufacturing method of the light-emitting device of this invention, it is preferable that the baking temperature in the said 1st baking process is more than the baking temperature in the said 2nd baking process.
Thereby, the oxidation of the first ink or the first functional layer can be performed efficiently.

[Application Example 4]
In the method for manufacturing a light emitting device of the present invention, it is preferable that the first film forming material and the second film forming material are different from each other.

  Thereby, each characteristic of the 1st functional layer and the 2nd functional layer can be made excellent.

[Application Example 5]
In the method for manufacturing a light emitting device of the present invention, the light emitting device comprises:
A first anode provided in the first pixel region;
A second anode provided in a second pixel region different from the first pixel region;
A common cathode provided in common to the first pixel region and the second pixel region;
A first light emitting functional layer provided between the first anode, the second anode, and the common cathode in common with the first pixel region and the second pixel region, and having a function of emitting light in a first color; ,
A second light emitting functional layer provided between the first light emitting functional layer and the second anode and having a function of emitting light in a second color different from the first color;
A first hole injection layer provided between the first light emitting functional layer and the first anode;
A second hole injection layer provided between the second light emitting functional layer and the second anode,
The first hole injection layer is the first functional layer;
The second hole injection layer is preferably the second functional layer.

  Thereby, the 1st positive hole injection layer and the 2nd positive hole injection layer which have the outstanding characteristic can be obtained. In particular, in a light-emitting device (hybrid type light-emitting device) having a first light-emitting functional layer that is such a common light-emitting functional layer, generally excellent hole injection properties are required for the first hole injection layer, The constituent material of the second hole injection layer is liable to be deteriorated by oxidation. Therefore, when the present invention is applied to such a light emitting device, the effect becomes remarkable.

[Application Example 6]
In the method for manufacturing a light emitting device of the present invention, a third anode provided in a third pixel region different from the first pixel region and the second pixel region;
The common cathode provided in common in the first pixel region, the second pixel region, and the third pixel region;
The first anode, the second anode, and the first anode provided between the third anode and the common cathode in common with the first pixel region, the second pixel region, and the third pixel region. A light emitting functional layer;
A third light emitting functional layer provided between the first light emitting functional layer and the third anode and having a function of emitting light in a third color different from the first color and the second color;
A third hole injection layer provided between the third light emitting functional layer and the third anode,
Each of the second hole injection layer and the third hole injection layer is preferably the second functional layer.

  Thereby, the 1st hole injection layer, the 2nd hole injection layer, and the 3rd hole injection layer which have the outstanding characteristic can be obtained.

[Application Example 7]
In the method for manufacturing a light emitting device of the present invention, it is preferable that the first color is blue, the second color is red, and the third color is green.
Thereby, a display device capable of full color display can be realized.

[Application Example 8]
In the method for manufacturing a light emitting device of the present invention, a third ink application step of applying a third ink containing a third film-forming material on the first functional layer or the second functional layer;
A third firing step of forming a third functional layer by drying the third ink applied on the first functional layer or the second functional layer, followed by firing in an inert gas atmosphere; It is preferable to have.

  Thereby, the third functional layer can be formed while maintaining the necessary characteristics of the first functional layer and the second functional layer.

[Application Example 9]
In the method for manufacturing a light emitting device of the present invention, the third functional layer is preferably a hole transport layer.

  Thereby, it is possible to form the hole transport layer while maintaining the necessary characteristics of the first functional layer and the second functional layer.

[Application Example 10]
The light emitting device of the present invention is manufactured using the method for manufacturing a light emitting device of the present invention.
According to such a light emitting device, excellent characteristics can be exhibited.

[Application Example 11]
An electronic apparatus according to the present invention includes the light emitting device according to the present invention.
According to such an electronic device, the light-emitting device can exhibit excellent characteristics.

It is sectional drawing which shows the light-emitting device (display apparatus) which concerns on 1st Embodiment of this invention. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. It is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. It is a figure for demonstrating the manufacturing method of the light-emitting device which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the light-emitting device (display apparatus) which concerns on 3rd Embodiment of this invention. 1 is a perspective view illustrating a configuration of a mobile (or notebook) personal computer that is an example of an electronic apparatus of the present invention. It is a perspective view which shows the structure of the mobile telephone (PHS is also included) which is an example of the electronic device of this invention. 1 is a perspective view illustrating a configuration of a digital still camera that is an example of an electronic apparatus of the present invention.

  Hereinafter, a method for manufacturing a light-emitting device, a light-emitting device, and an electronic apparatus according to the invention will be described based on preferred embodiments shown in the drawings. In each drawing, the scale of each part is appropriately changed for convenience of explanation, and the illustrated configuration does not necessarily match the actual scale.

(Light emitting device)
First, a display device that is an example of the light-emitting device of the present invention will be described.

  FIG. 1 is a cross-sectional view showing a light emitting device (display device) according to a first embodiment of the present invention. In the following description, for convenience of explanation, the upper side in FIG. 1 will be described as “upper” and the lower side as “lower”.

  A light-emitting device 100 shown in FIG. 1 includes a plurality of light-emitting elements 1R, 1G, and 1B corresponding to sub-pixels 100R (R pixels), 100G (G pixels), and 100B (B pixels), and has a bottom emission display. The panel is configured. Here, the sub pixel 100B constitutes a “first pixel region”, the sub pixel 100R constitutes a “second pixel region”, and the sub pixel 100G constitutes a “third pixel region”. In the present embodiment, an example in which an active matrix method is employed as a display device driving method will be described. However, a passive matrix method may be employed.

  The light emitting device 100 includes a circuit board 20, a plurality of light emitting elements 1 R, 1 G, and 1 B provided on the circuit board 20, and a sealing substrate 40.

  The circuit board 20 includes a substrate 21, an interlayer insulating film 22 provided on the substrate 21, a plurality of switching elements 23, and wirings 24.

  The substrate 21 is substantially transparent (colorless transparent, colored transparent or translucent). Thereby, the light from each light emitting element 1R, 1G, 1B can be extracted from the substrate 21 side. Examples of the constituent material of the substrate 21 include resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyethersulfone, polymethyl methacrylate, polycarbonate, and polyarylate, quartz glass, and soda glass. Such glass materials can be used, and one or more of these can be used in combination.

  In the case of a top emission structure in which light from the light emitting elements 1R, 1G, and 1B is extracted from the side opposite to the substrate 21, the substrate 21 may be an opaque substrate. And a substrate made of an oxide film (insulating film) on the surface of a metal substrate such as stainless steel, a substrate made of a resin material, and the like.

  On such a substrate 21, a plurality of switching elements 23 are arranged in a matrix. Each switching element 23 is provided corresponding to each light emitting element 1R, 1G, 1B, and is a driving transistor for driving each light emitting element 1R, 1G, 1B.

  Each switching element 23 includes a semiconductor layer 231 made of silicon, a gate insulating layer 232 formed on the semiconductor layer 231, a gate electrode 233 formed on the gate insulating layer 232, a source electrode 234, A drain electrode 235.

  An interlayer insulating film 22 made of an insulating material is formed so as to cover the plurality of switching elements 23. A wiring 24 is provided in the interlayer insulating film 22.

  On the interlayer insulating film 22, light emitting elements 1R, 1G, and 1B are provided corresponding to the switching elements 23, respectively. In the present embodiment, the light emitting element 1R is configured to emit red (second color) light, the light emitting element 1G is configured to emit green (third color) light, and the light emitting element 1B includes: It is configured to emit blue (first color) light. Thereby, the light emitting device 100 (display device) for full color display can be realized.

  Specifically, the light emitting element 1R (second light emitting element) includes an anode 3R (second anode), a hole injection layer 4R (second hole injection layer), and a hole transport layer 5R on the interlayer insulating film 22. , Light emitting functional layer 6R (second light emitting functional layer), intermediate layer 7, light emitting functional layer 6B (first light emitting functional layer: common light emitting functional layer), electron transport layer 8, electron injection layer 9 and cathode 10 (second cathode) : Common cathode) are laminated in this order.

  Similarly, the light emitting element 1G (third light emitting element) includes an anode 3G (third anode), a hole injection layer 4G (third hole injection layer), a hole transport layer 5G, a light emitting element on the interlayer insulating film 22. Functional layer 6G (third light emitting functional layer), intermediate layer 7, light emitting functional layer 6B (first light emitting functional layer: common light emitting functional layer), electron transport layer 8, electron injection layer 9, and cathode 10 (third cathode: common) The cathode) is laminated in this order.

  On the other hand, the light emitting element 1B (first light emitting element) includes an anode 3B (first anode), a hole injection layer 4B (first hole injection layer), a hole transport layer 5B, and an intermediate layer on the interlayer insulating film 22. 7. A light emitting functional layer 6B (first light emitting functional layer: common light emitting functional layer), an electron transport layer 8, an electron injection layer 9, and a cathode 10 (first cathode: common cathode) are laminated in this order.

  Here, the anodes 3R, 3G, and 3B constitute pixel electrodes individually provided for the corresponding light emitting elements 1R, 1G, and 1B (each subpixel), and are connected to the drain electrode of the switching element 23 via the wiring 24. Electrically connected. Further, the hole injection layers 4R, 4G, and 4B, the hole transport layers 5R, 5G, and 5B, the light emitting functional layer 6R, and the light emitting functional layer 6G are also provided individually for the corresponding light emitting elements 1R, 1G, and 1B. . Hereinafter, the light emitting elements 1R, 1G, and 1B are collectively referred to as “light emitting element 1”, the anodes 3R, 3G, and 3B are collectively referred to as “anode 3”, and the hole injection layers 4R, 4G, and 4B are collectively referred to. The “hole injection layer 4” and the hole transport layers 5R, 5G, and 5B are collectively referred to as “hole transport layer 5”.

  On the other hand, the cathode 10 constitutes a common electrode provided in common with the light emitting elements 1R, 1G, and 1B. Further, the intermediate layer 7, the light emitting functional layer 6B, the electron transport layer 8 and the electron injection layer 9 are also provided in common to the light emitting elements 1R, 1G and 1B.

  According to such a hybrid light emitting device 100, the hole transport layers 5R, 5G, and 5B, the light emitting functional layers 6R and 6G, and the like are individually formed for each element using a liquid phase process, and a gas phase process is performed. The intermediate layer 7 and the light emitting functional layer 6B can be formed in common for the three elements. Therefore, the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

  A partition wall 31 (bank) made of a resin material is provided between the adjacent light emitting elements 1R, 1G, and 1B. Moreover, the sealing substrate 40 is joined to such light emitting elements 1R, 1G, and 1B through a resin layer 32 made of a thermosetting resin such as an epoxy resin.

  As described above, since each of the light emitting elements 1R, 1G, and 1B of the present embodiment is a bottom emission type, the sealing substrate 40 may be a transparent substrate or an opaque substrate. As a constituent material, the same material as the substrate 21 described above can be used.

Hereinafter, the light emitting elements 1R, 1G, and 1B will be described in detail.
In the light emitting elements 1R, 1G, 1B, electrons are supplied (injected) from the cathode 10 side to the light emitting functional layers 6R, 6G, 6B, and holes are supplied (injected) from the anodes 3R, 3G, 3B side. The In the light emitting functional layers 6R, 6G, and 6B, holes and electrons recombine, and excitons are generated by the energy released during the recombination, and the excitons return to the ground state. Emits energy (fluorescence or phosphorescence).

  Here, although the light emitting functional layers 6B are provided in the light emitting elements 1R and 1G, the light emitting functional layers 6R and 6G selectively emit light without causing the light emitting functional layer 6B to emit light. Thereby, the light emitting elements 1R, 1G, and 1B emit light in red, green, and blue, respectively.

Hereinafter, the configuration of each part of the light emitting elements 1R, 1G, and 1B will be briefly described.
(anode)
The anode 3 (3R, 3G, 3B) is an electrode that injects holes into the hole injection layer 4 (4R, 4G, 4B). As the constituent materials of the anodes 3R, 3G, and 3B, it is preferable to use materials having a large work function and excellent conductivity.

Specifically, the constituent materials of the anodes 3R, 3G, and 3B are, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing, respectively. Examples thereof include oxides such as ZnO, Au, Pt, Ag, Cu, and alloys containing these, and one or more of these can be used in combination. The constituent materials of the anodes 3R, 3G, and 3B may be the same or different from each other, but by using the same materials, the anodes 3R, 3G, and 3B can be collectively formed. Productivity can be increased.

(Hole injection layer)
The hole injection layer 4 (4R, 4G, 4B) has a function of improving the hole injection efficiency from the anode 3 (3R, 3G, 3B).

  The constituent materials (hole injection materials) of the hole injection layers 4R, 4G, and 4B are not particularly limited. For example, TAPC ((1,1-bis [4- (di-p-tolyl) ) Ami.Nophenyl] cyclohexane)): 4,4'-Cyclohexylidenebis [N, N-bis (4-methylphenyl) aniline]), TPD (N, N'-diphenyl-N, N'-bis- (3-methyl) Phenyl) -1,1′biphenyl-4,4′-diamine), α-NPD (N, N′-diphenyl-N, N′-bis- (1-naphthyl) -1,1′biphenyl-4,4 '-Diamine), m-MTDATA (4,4', 4 "-tris (N-3-methylphenylamino) -triphenylamine: 4,4 ', 4" -Tris (N-3-methylphenyl-N- phenylamino) -triphenylamine), 2-TNATA (4,4 ′, 4 ″ -tris (N, N- (2-naphthyl) phenylamino) triphenylamine), TCTA (4,4 ′, 4 ″ -tri (N -Carbazole group) Phenylamine: Tris- (4-carbazoyl-9-yl-phenyl) -amine), TDAPB (1,3,5-tris- (N, N-bis- (4-methoxy-phenyl) -aminophenyl) -benzene : 1,3,5-tris [4- (diphenylamino) phenyl] benzene), spiro TAD, HTM1 (Tri-p-tolylamineHTM2,1,1-bis [(di-4-tolylamino) phenyl] cyclohexane), HTM2 ( 1,1-bis [(di-4-tolylamino) phenyl] cyclohexane), TPT1 (1,3,5-tris (4-pyridyl) -2,4,6-triazin), TPTE (Triphenylamine-tetramer), TFB (Poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)) and other amine compounds such as triphenylamine polymers, polyfluorene derivatives (PF), polyparaphenylene vinylene derivatives ( PPV), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiophene derivative, polymethylphenylsilane (PMPS) Polymer materials such as polysilanes, including "L-source" manufactured by Nissan Chemical Co., Ltd., "Verazol" manufactured by Soken Chemical Co., Ltd., "NDP-9" manufactured by NOVALED, etc. Two or more kinds can be used in combination.

  Here, the hole injection layer 4B is made of a material different from the hole injection layers 4R and 4G. In other words, the hole injection layer 4B is made of a material having a conductivity (hole injection property / hole transport property) different from that of the hole injection layer 4R and the hole injection layer 4G. Thereby, each characteristic of hole injection layer 4R, 4G, 4B can be optimized. Therefore, the characteristics of the light emitting device 100 can be improved. For example, the thickness of each of the hole injection layers 4R, 4G, and 4B can be optimized, and the carrier balance of the subpixels 100R, 100G, and 100B can be optimized, and the subpixels 100R, 100G, and 100B can be optimized. It is possible to efficiently emit light with a desired color or to reduce deterioration due to electrons of the hole injection layers 4R, 4G, and 4B, and the characteristics of the light emitting device 100 can be improved.

  Here, the conductivity of the constituent material of the hole injection layer 4B is preferably higher than the conductivity of the constituent material of the hole injection layers 4R and 4G. Thereby, the hole transport property of the constituent material of the hole injection layer 4B is made higher than the hole transport property of the constituent material of the hole injection layers 4R and 4G, and the blue pixel can emit light efficiently. This is because the blue light emitting material contained in the light emitting functional layer 6B has a larger band gap than the red light emitting material and green light emitting material contained in the light emitting functional layers 6R and 6G, and has a larger energy (carrier amount) for light emission. Is necessary.

  Further, in the hybrid light emitting device 100 as in the present embodiment, since the light emitting functional layer 6B is formed by a vapor deposition method as will be described later, the electron transporting property of the light emitting functional layer 6B is usually in the liquid phase. It becomes higher than the light emitting functional layers 6R and 6G formed by the process. For this reason, if the hole injection property of the hole injection layer 4B is low, electrons and holes cannot be injected into the light emitting functional layer 6B in a balanced manner in the subpixel 100B, or electrons may be injected into the hole injection layer 4B or the like. May enter the anode 3B side and cause deterioration of the hole injection layer 4B. Therefore, these problems can be solved by making the conductivity of the constituent material of the hole injection layer 4B higher than the conductivity of the constituent material of the hole injection layers 4R and 4G.

  From the above viewpoint, as a specific constituent material of the hole injection layer 4B, for example, an ion conductive hole injection material obtained by adding an electron accepting compound to a conductive polymer material (or conductive oligomer material). Are preferably used. As such an ion conductive hole injection material, for example, a polythiophone-based hole injection material or a polyaniline-based hole injection material can be used.

  Moreover, as a specific constituent material of the hole injection layers 4R and 4G, for example, an aromatic amine compound, a carbazole compound, a thiophene compound, and those obtained by adding an electron-accepting compound to the compound are preferably used.

  Further, the constituent materials of the hole injection layers 4R and 4G may be the same as or different from each other. When the constituent materials of the hole injection layers 4R and 4G are the same, the number of materials forming these layers can be reduced, and the cost can be reduced. On the other hand, when the constituent materials of the hole injection layers 4R and 4G are different from each other, the characteristics of these layers can be easily optimized.

  The film thickness of the hole injection layer 4B is preferably different from the film thickness of the hole injection layers 4R and 4G. Thereby, the film thickness of each of the hole injection layers 4R and 4B can be optimized.

  Similarly, the thicknesses of the hole injection layers 4R and 4G are preferably different from each other. Thereby, each film thickness of hole injection layer 4R, 4G can be optimized.

  The thicknesses of the hole injection layers 4R, 4G, and 4B are not particularly limited, but are preferably in the range of 10 nm to 300 nm, and more preferably in the range of 40 nm to 150 nm. . The thicknesses of the hole injection layers 4R, 4G, and 4B may be the same as or different from each other.

(Hole transport layer, intermediate layer)
The hole transport layer 5R (second hole transport layer) has a function of transporting holes injected from the anode 3R through the hole injection layer 4R to the light emitting functional layer 6R. Similarly, the hole transport layer 5G (third hole transport layer) has a function of transporting holes injected from the anode 3G through the hole injection layer 4G to the light emitting functional layer 6G.

  In addition, the hole transport layer 5R has an electron blocking property and also has a function of preventing a functional deterioration of the hole injection layer 4R due to electrons entering the hole injection layer 4R. Similarly, the hole transport layer 5G has an electron blocking property, and also has a function of preventing a functional deterioration of the hole injection layer 4G due to electrons entering the hole injection layer 4G.

  The hole transport layer 5B (first hole transport layer) and the intermediate layer 7 have a function of transporting holes injected from the anode 3B through the hole injection layer 4B to the light emitting functional layer 6B.

  In addition, the hole transport layer 5B and the intermediate layer 7 have an electron blocking property, and also have a function of preventing a functional deterioration of the hole injection layer 4B due to electrons entering the hole injection layer 4B. Since the intermediate layer 7 is extremely thin as will be described later, the electron blocking property of the intermediate layer 7 alone is extremely low and does not hinder the movement of electrons in the light emitting elements 1R and 1G.

  Examples of the constituent material of the hole transport layers 5R, 5G, and 5B include triphenylamine polymers such as TFB (poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)). Amine-based compounds, polyfluorene derivatives (PF), polyparaphenylene vinylene derivatives (PPV), polyparaphenylene derivatives (PPP), polyvinylcarbazole (PVK), polythiophene derivatives, polysilanes including polymethylphenylsilane (PMPS) High molecular hole transport materials such as m-MTDATA (4,4 ', 4 "-tris (N-3-methylphenylamino) -triphenylamine), TCTA (4,4', 4"- Low molecular hole transport materials such as tri (N-carbazole group) triphenylamine) and α-NPD (bis (N- (1-naphthyl) -N-phenyl) benzidine). 1 type or 2 types or more of these can be used in combination. The constituent materials of the hole transport layers 5R, 5G, and 5B (first hole transport layer, second hole transport layer, and third hole transport layer) may be the same as or different from each other. , The constituent materials of the hole transport layers 5R, 5G (first hole transport layer, third hole transport layer) are the same, and the constituent materials of the hole transport layer 5B (second hole transport layer) are By being different from the hole transport layers 5R and 5G, the light emission balance between the light emitting elements 1R and 1G and the light emitting element 1B can be easily adjusted.

  Here, the hole transport layer 5B is preferably made of a material different from the hole transport layers 5R and 5G. Thereby, each characteristic of hole transport layer 5R, 5G, 5B can be optimized.

  Moreover, the constituent materials of the hole transport male totals 5R and 5G may be the same as or different from each other. When the constituent materials of the hole transport layers 45 and 5G are the same, the number of materials forming these layers can be reduced, and the cost can be reduced. On the other hand, when the constituent materials of the hole transport layers 5R and 5G are different from each other, the characteristics of these layers can be easily optimized.

  The film thickness of the hole transport layer 5B is preferably different from the film thickness of the hole transport layers 5R and 5G. Thereby, each film thickness of the positive hole transport layers 5R and 5B can be optimized.

  Furthermore, the hole transport layers 5R, 5G, and 5B preferably have different film thicknesses. Thereby, the film thickness of each of the hole transport layers 5R, 5G, and 5B can be optimized.

  The thicknesses of the hole transport layers 5R, 5G, and 5B are not particularly limited, but are preferably in the range of 15 nm to 25 nm.

  Examples of the constituent material of the intermediate layer 7 include m-MTDATA (4,4 ′, 4 ″ -tris (N-3-methylphenylamino) -triphenylamine) and TCTA (4,4 ′, 4 ″). Low molecular hole transport materials such as -tri (N-carbazole group) triphenylamine) and α-NPD (bis (N- (1-naphthyl) -N-phenyl) benzidine). One kind or a combination of two or more kinds can be used. The constituent material of the intermediate layer 7 (common hole transport layer) may be the same as or different from the hole transport layers 5R, 5G, and 5B, but the hole transport layer 5B (second hole transport layer). By including the same or similar material as the constituent material of the layer, carriers (holes) can be smoothly transported from the hole transport layer 5B to the light emitting functional layer 6B via the intermediate layer 7.

  Further, the thickness t of the intermediate layer 7 is preferably 2 nm or less, more preferably 0.1 nm or more and 1.5 nm or less, further preferably 0.1 nm or more and 1 nm or less, and 0.1 nm The thickness is most preferably 0.9 nm or less. Thereby, in the light emitting elements 1R and 1G, since the thickness of the intermediate layer 7 provided between the light emitting functional layers 6R and 6G and the light emitting functional layer 6B is extremely thin, the light emitting functional layers 6B to 6R, Carriers (electrons) can be delivered to 6G. Therefore, the light emitting functional layers 6R and 6G can selectively emit light without causing the light emitting functional layers 6B to emit light in the light emitting elements 1R and 1G. Since the thickness of the intermediate layer 7 is extremely thin, an increase in the driving voltage of the light emitting elements 1R, 1G, and 1B due to the provision of the intermediate layer 7 can be suppressed.

  Here, since the constituent material of the intermediate layer 7 has the electron blocking property as described above, the light emitting functional layer 6B can efficiently emit light by utilizing the electron blocking property of the intermediate layer 7 in the light emitting element 1B. On the other hand, in the light emitting elements 1R and 1G, if the electronic block property of the intermediate layer 7 is too high, light emission by the light emitting functional layers 6R and 6G does not occur or the light emission efficiency is remarkably lowered. Therefore, it is extremely useful to make the thickness of the intermediate layer 7 extremely thin so that the electron blocking property of the intermediate layer 7 in the light emitting elements 1R and 1G is lowered.

On the other hand, when the thickness t of the intermediate layer 7 is too thin, the above-described effect due to the provision of the intermediate layer 7 tends to become extremely small. On the other hand, if the thickness t of the intermediate layer 7 is too thick, the driving voltage of the light emitting elements 1R and 1G increases rapidly (the light emission efficiency decreases rapidly), or the light emitting functional layer 6B in the light emitting elements 1R and 1G As a result, light of a desired color cannot be obtained.
The intermediate layer 7 may be omitted.

(Light emitting functional layer)
The light emitting functional layer 6R is provided in contact with the hole transport layer 5R. The light emitting functional layer 6G is provided in contact with the hole transport layer 5G. The light emitting functional layer 6B is provided in contact with the intermediate layer 7.

  Each of the light emitting functional layers 6R, 6G, and 6B includes a light emitting material. The light emitting material is not particularly limited, and various fluorescent materials and phosphorescent materials can be used singly or in combination, and the light emitting functional layer 6R is made of a red fluorescent material or a red phosphorescent material as the light emitting material. The light emitting functional layer 6G uses a green fluorescent material or a green phosphorescent material as a light emitting material, and the light emitting functional layer 6B uses a blue fluorescent material or a blue phosphorescent material as a light emitting material.

  The red fluorescent material is not particularly limited as long as it emits red fluorescence. For example, perylene derivatives such as diindenoperylene derivatives, europium complexes, benzopyran derivatives, rhodamine derivatives, benzothioxanthene derivatives, porphyrin derivatives, Nile Red, 2- (1,1-dimethylethyl) -6- (2- (2,3,6,7-tetrahydro-1,1,7,7-tetramethyl-1H, 5H-benzo (ij) quinolidine- 9-yl) ethenyl) -4H-pyran-4H-ylidene) propanedinitrile (DCJTB), 4- (dicyanomethylene) -2-methyl-6- (p-dimethylaminostyryl) -4H-pyran (DCM), ADS111RE (manufactured by American Dice Source) and the like can be mentioned.

  The red phosphorescent material is not particularly limited as long as it emits red phosphorescence. For example, Bt2Ir (acac) (Bis (2-phenylbenxothiozolato-N, C2 ′) Iridium (III) (acetylacetonate)), Btp2Ir (acac ) (Bis (2,2′-benzothienyl) -pyridinato-N, C3) Iridium (acetylacetonate)), PtOEP (2,3,7,8,12,13,17,18-Octaethyl-21H, And platinum complexes such as 23H-porphine and platinum (II)).

  The green fluorescent material is not particularly limited as long as it emits green fluorescence. For example, quinacridone such as coumarin derivatives and quinacridone derivatives and derivatives thereof, 9,10-bis [(9-ethyl-3-carbazole)- Vinylenyl] -anthracene, poly (9,9-dihexyl-2,7-vinylenefluorenylene), poly [(9,9-dioctylfluorene-2,7-diyl) -co- (1,4-diphenylene-vinylene) -2-methoxy-5- {2-ethylhexyloxy} benzene)], poly [(9,9-dioctyl-2,7-divinylenefluorenylene) -ortho-co- (2-methoxy-5- (2 -Ethoxylhexyloxy) -1,4-phenylene)], ADS109GE (manufactured by American Dice Source), and the like.

  The green phosphorescent material is not particularly limited as long as it emits green phosphorescence. For example, Ir (ppy) 3 (Fac-tris (2-phenypyridine) iridium), Ppy2Ir (acac) (Bis (2-phenyl-) pyridinato-N, C2) Iridium (acetylacetone)) and the like.

  The blue fluorescent material is not particularly limited as long as it emits blue fluorescence. For example, distyrylamine derivatives such as distyryldiamine compounds, fluoranthene derivatives, pyrene derivatives, perylene and perylene derivatives, anthracene derivatives, benzo Oxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, chrysene derivatives, phenanthrene derivatives, distyrylbenzene derivatives, tetraphenylbutadiene, 4,4′-bis (9-ethyl-3-carbazovinylene) -1,1′-biphenyl (BCzVBi) ), Poly [(9.9-dioctylfluorene-2,7-diyl) -co- (2,5-dimethoxybenzene-1,4-diyl)], poly [(9,9-dihexyloxyfluorene-2, 7-diyl) -ortho-co- (2-me Xyl-5- {2-ethoxyhexyloxy} phenylene-1,4-diyl)], poly [(9,9-dioctylfluorene-2,7-diyl) -co- (ethylnylbenzene)], ADS136BE (American) Die Source).

  The blue phosphorescent material is not particularly limited as long as it emits blue phosphorescence. For example, FIrpic (Iridium-bis (4,6-difluorophenyl-pyridinato-N, C2) -picolinate), Ir (pmb) 3 (Iridium-tris (1-phenyl-3-methylbenzimidazolin-2-ylidene-C, C (2) ′), FIrN4 (Iridium (III) bis (4,6-difluorophenylpyridinato) (5- (pyridin-2-yl) -Tetrazolate)), FIrtaz (Iridium (III) bis (4,6-difluorophenylpyridinato) (5- (pyridine-2-yl) -1,2,4-triazolate)) and the like.

  In addition, the light emitting functional layers 6R, 6G, and 6B may contain a host material to which the light emitting material is added as a guest material in addition to the light emitting material described above. This host material recombines holes and electrons to generate excitons and to transfer the exciton energy to the luminescent material (Felster movement or Dexter movement) to excite the luminescent material. Have. In the case of using such a host material, for example, the host material can be used by doping a light emitting material that is a guest material as a dopant.

  Such a host material is not particularly limited as long as it exhibits the functions described above for the light emitting material to be used. For example, TDAPB (1,3,5-tris- (N, N-bis -(4-methoxy-phenyl) -aminophenyl) -benzene), CBP (4,4'-bis (9-dicarbazolyl) -2,2'-biphenyl), BAlq (Bis- (2-methyl-8-quinolinolate) ) -4- (phenylphenolate) aluminium), mCP (N, N-dicarbazolyl-3,5-benzene: CBP derivative), CDBP (4,4′-bis (9-carbazolyl) -2,2′-dimethyl-biphenyl) ), DCB (N, N′-Dicarbazolyl-1,4-dimethene-benzene), P06 (2,7-bis (diphenylphosphineoxide) 9,9-dimethylfluorene), SimCP (3,5-bis (9-carbazolyl) tetraphenylsilane) ), UGH3 (W-bis (triphenylsilyl benzene) host material of low molecular weight can be mentioned, such as may be used singly or in combination of two or more of them.

  The constituent materials of the light emitting functional layers 6R and 6G are preferably soluble in a solvent capable of dissolving the constituent materials of the hole transport layers 5R and 5G described above. Thereby, the light emitting functional layers 6R and 6G and the hole transport layers 5R and 5G can be formed by a liquid phase process using the same solvent. That is, when the light emitting functional layers 6R and 6G are formed by a liquid phase process, the same solvent as that used when the hole transport layers 5R and 5G are formed by a liquid phase process can be used. As a result, the adhesion or affinity of the interface between the light emitting functional layers 6R, 6G and the hole transport layers 5R, 5G is increased, and carriers (positive) from the hole transport layers 5R, 5G to the light emitting functional layers 6R, 6G are increased. Hole) can be improved.

  The constituent materials of the light emitting functional layers 6R and 6G are preferably composed of a low molecular material as a main material, and more preferably composed of a low molecular guest material and a low molecular host material as a main material. preferable. Thereby, the luminous efficiency of the light emitting functional layers 6R and 6G can be increased, and the decrease in the luminous efficiency of the light emitting elements 1R and 1G due to the provision of the intermediate layer 7 can be compensated. As a result, the light emission balance between the light emitting elements 1R and 1G and the light emitting element 1B can be made excellent. From such a viewpoint, the content of the low molecular material in the light emitting functional layers 6R and 6G is preferably 60 wt% or more, more preferably 80 wt% or more, and further preferably 90 wt% or more. .

  The thicknesses of such light emitting functional layers 6R, 6G, and 6B are not particularly limited, but are preferably in the range of 5 nm to 100 nm, and more preferably in the range of 10 nm to 50 nm.

(Electron transport layer)
The electron transport layer 8 has a function of transporting electrons injected from the cathode 10 through the electron injection layer 9 to the light emitting functional layer 6B.

  As a constituent material (electron transport material) of the electron transport layer 8, for example, BALq, OXD-1 (1,3,5-tri (5- (4-tert-butylphenyl) -1,3,4-oxadi) Azole)), BCP (Bathocuproine), PBD (2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,2,4-oxadiazole), TAZ (3- (4-biphenyl) -5- (4-tert-butylphenyl) -1,2,4-triazole), DPVBi (4,4'-bis (1,1-bis-diphenylethenyl) biphenyl), BND (2,5-bis ( 1-naphthyl) -1,3,4-oxadiazole), DTVBi (4,4′-bis (1,1-bis (4-methylphenyl) ethenyl) biphenyl), BBD (2,5-bis (4 -Biphenylyl) -1, 3,4-oxadiazole), tris (8-quinolinolato) aluminum (Alq3), oxadiazole derivatives, oxazole derivatives, phenanthoroline derivatives, anthraquinodimethane derivatives, benzoquinone derivatives, naphthoquinone derivatives, anthraquinone derivatives, tetracyano Anthraquinodimethane derivatives, fluorene derivatives, diphenyldicyanoethylene derivatives, diphenoquinone derivatives, hydroxyquinoline derivatives and the like can be mentioned, and one or more of these can be used in combination.

  Although the thickness of the electron carrying layer 8 is not specifically limited, It is preferable to exist in the range of 1 nm or more and 100 nm or less, and it is more preferable to exist in the range of 5 nm or more and 50 nm or less.

  The electron transport layer 8 can be omitted depending on the constituent material and thickness of other layers.

(Electron injection layer)
The electron injection layer 9 has a function of improving the efficiency of electron injection from the cathode 10.

  Examples of the constituent material (electron injection material) of the electron injection layer 9 include various inorganic insulating materials and various inorganic semiconductor materials.

  Examples of such inorganic insulating materials include alkali metal chalcogenides (oxides, sulfides, selenides, tellurides), alkaline earth metal chalcogenides, alkali metal halides, and alkaline earth metal halides. Of these, one or two or more of these can be used in combination. By forming the electron injection layer using these as main materials, the electron injection property can be further improved. In particular, alkali metal compounds (alkali metal chalcogenides, alkali metal halides, and the like) have a very low work function, and the light-emitting element 1 can obtain high luminance by forming the electron injection layer 9 using the work function. Become.

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

  In addition, as the inorganic semiconductor material, for example, an oxide including at least one element of Li, Na, Ba, Ca, Sr, Yb, Al, Ga, In, Cd, Mg, Si, Ta, Sb, and Zn , Nitrides, oxynitrides, and the like, and one or more of these can be used in combination.

  The thickness of the electron injection layer 9 is not particularly limited, but is preferably in the range of 0.01 nm to 10 nm, and more preferably in the range of 0.1 nm to 10 nm.

  The electron injection layer 9 can be omitted depending on the constituent material and thickness of other layers.

(cathode)
The cathode 10 is an electrode that injects electrons into the electron transport layer 8 through the electron injection layer 9. As a constituent material of the cathode 10, it is preferable to use a material having a small work function.

  Examples of the constituent material of the cathode 10 include Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, Yb, Ag, Cu, Al, Cs, Rb, and alloys containing these. These can be used alone or in combination of two or more thereof (for example, a multi-layer laminate).

  In particular, when an alloy is used as the constituent material of the cathode 10, it is preferable to use an alloy containing a stable metal element such as Ag, Al, or Cu, specifically, an alloy such as MgAg, AlLi, or CuLi. By using such an alloy as a constituent material of the cathode 10, the electron injection efficiency and stability of the cathode 10 can be improved.

  Moreover, since the light emitting element 1 of this embodiment is a bottom emission type, the cathode 10 does not need to have a light transmittance. In the case of the bottom emission type, as the constituent material of the cathode 10, for example, a metal or an alloy such as Al, Ag, AlAg, and AlNd is preferably used. By using such a metal or alloy as a constituent material of the cathode 10, the electron injection efficiency and stability of the cathode 10 can be improved.

  The thickness of the cathode 10 in the case of the bottom emission type is not particularly limited, but is preferably in the range of 50 nm to 1000 nm, and more preferably in the range of 100 nm to 500 nm.

  In addition, when the light emitting element 1 is a top emission type, it is preferable to use a metal or an alloy such as MgAg, MgAl, MgAu, and AlAg as a constituent material of the cathode 10. By using such a metal or alloy as the constituent material of the cathode 10, it is possible to improve the electron injection efficiency and stability of the cathode 10 while ensuring the light transmittance of the cathode 10.

  The thickness of the cathode 10 in the case of the top emission type is not particularly limited, but is preferably in the range of 1 nm to 50 nm, and more preferably in the range of 5 nm to 20 nm.

  According to the light emitting device 100 configured as described above, the hole injection layers 4R, 4G, and 4R, the hole transport layers 5R, 5G, and 5B and the light emitting function using a liquid phase process, as will be described in detail later. The layers 6R and 6G can be individually formed for each element, and the intermediate layer 7 and the light emitting functional layer 6B can be formed in common to the light emitting elements 1R, 1G, and 1B by using a vapor phase process. Therefore, the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

  In particular, as will be described in detail below, the light emitting device 100 has different firing conditions for the hole injection layers 4R, 4G and the hole injection layer 4B when forming the hole injection layers 4R, 4G, 4B. Hole injection layers 4R, 4G, and 4B having excellent characteristics can be formed, and excellent characteristics can be exhibited.

(Method for manufacturing light emitting device)
Hereinafter, an example of a method for manufacturing the above-described light emitting device 100 will be described.

  2-4 is a figure for demonstrating the manufacturing method of the light-emitting device shown in FIG. Hereinafter, each process is demonstrated one by one.

[1]
First, the circuit board 20 is prepared. As shown in FIG. 2A, after the anodes 3R, 3G, and 3B are formed on the circuit board 20, the partition walls 31 are formed.

  The anodes 3R, 3G, and 3B are formed by, for example, forming an electrode material on the circuit board 20 by using a vapor deposition method such as an evaporation method or a CVD method, and then patterning the electrode material by etching or the like. can get.

  The partition wall 31 can be formed by patterning using a photolithography method or the like so that the anodes 3R, 3G, and 3B are exposed.

Here, the constituent material of the partition wall 31 is selected in consideration of heat resistance, liquid repellency, ink solvent resistance, adhesion to the circuit board 20 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 .

  In addition, after the formation of the anodes 3R, 3G, and 3B and the partition walls 31, the surfaces of the anodes 3R, 3G, and 3B and the partition walls 31 may be subjected to oxygen plasma treatment as necessary. Thereby, lyophilicity is imparted to the surfaces of the anodes 3R, 3G, and 3B, organic substances adhering to the surfaces of the anodes 3R, 3G, and 3B and the partition wall 31 are removed (washed), and the anodes 3R, 3G, and 3B The work function near the surface can be adjusted.

  Here, as conditions for the oxygen plasma treatment, for example, the plasma power is about 100 to 800 W, the oxygen gas flow rate is about 50 to 100 mL / min, and the conveyance speed of the member to be treated (anode 3R, 3G, 3B) is 0.5 to 10 mm / min. It is preferable that the temperature of the circuit board 20 is about 70 to 90 ° C. for about sec.

Further, after this oxygen plasma treatment, it is preferable to perform a plasma treatment using a fluorine-based gas such as CF ₄ as a treatment 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, it is possible to reduce the unintentional wetting and spreading of the liquid applied in the partition wall 31.

[2]
2-1
Next, as shown in FIG. 2B, the ink 4 a (first ink) for forming the hole injection layer is applied from the inkjet head 200 onto the anode 3 </ b> B in the partition wall 31.

  The ink 4a is obtained by dissolving the constituent material of the hole injection layer 5B or its precursor (first film forming material) in a solvent or dispersing it in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  As described above, the first ink application step of applying the ink 4a, which is the first ink containing the first film forming material, to the sub-pixel 100B (first pixel region) is performed.

2-2
Thereafter, the ink 4a on the anode 3B is dried (desolvent or dedispersing medium) and subjected to heat treatment (firing), thereby forming the hole injection layer 4B as shown in FIG.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry in an oven at atmospheric pressure (in an oxygen gas atmosphere) or in a hot plate at 100 to 250 ° C. for about 5 to 30 minutes. Thereby, the hole injection layer 4B having flat and excellent characteristics can be formed. Further, by firing in an oxygen gas atmosphere, the oxidation of the material of the obtained hole injection layer 4B can be promoted, and the hole injection layer 4B having high conductivity (hole injection property) can be obtained.

  Moreover, it is preferable that the calcination temperature in this process is more than the calcination temperature in the 2nd baking process mentioned later. Thereby, the ink 4a or the hole injection layer 4B can be oxidized efficiently.

  As described above, the ink 4a applied to the sub-pixel 100B is dried and then fired in an oxygen gas atmosphere, thereby performing the first firing step of forming the hole injection layer 4B as the first functional layer.

2-3
Next, as shown in FIG. 2D, the ink 4 b for forming the hole injection layer is applied from the inkjet head 200 onto the anodes 3 </ b> R and 3 </ b> G in the partition wall 31.

  The ink 4b is obtained by dissolving a constituent material of the hole injection layers 4R and 4G (a material different from the constituent material of the hole injection layer 4B) or a precursor thereof (second film forming material) in a solvent or dispersing it in a dispersion medium. It will be. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  Here, the film-forming material contained in the ink 4b is different from the film-forming material contained in the ink 4a, whereby the characteristics of the obtained hole injection layers 4R, 4G, and 4B can be made excellent. .

  As described above, the second ink application step of applying the ink 4b, which is the second ink containing the second film forming material, to the sub-pixels 100R and 100G (second and third pixel regions) is performed.

2-4
Thereafter, the ink 4b on the anodes 3R and 3G is dried (desolvent or dedispersing medium) and heated (baked) to form hole injection layers 4R and 4G as shown in FIG. To do.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry in an oven in an inert gas atmosphere such as nitrogen gas or in a hot plate at 100 to 250 ° C. for about 5 to 30 minutes. Thereby, it is possible to form the hole injection layers 4R and 4G which are flat and have excellent characteristics. In addition, by firing in an inert gas atmosphere, the oxidation of the material of the obtained hole injection layers 4R and 4G is reduced, and a hole injection layer 4B having high conductivity (hole injection property) is obtained. Can do. In particular, hole injection materials suitable for red and green pixels are generally easy to oxidize, and when oxidized, the hole injection property decreases, and thus firing is performed in an inert gas atmosphere. It is beneficial to do.

  As described above, the ink 4b applied to the sub-pixels 100R and 100G is dried and then baked in an inert gas atmosphere, thereby forming the second functional layer hole injection layers 4R and 4G. A baking process is performed.

  As described above, the hole injection layers 4R, 4G, and 4B are formed by the liquid phase process using the inks 4a and 4b.

  According to such a method of forming the hole injection layers 4R, 4G, and 4B, the constituent material (first film forming material) of the hole injection layer 4B is a material whose characteristics are improved by oxidation, and the hole injection layer 4R. When the 4G constituent material (second film forming material) is a material whose characteristics are deteriorated by oxidation, the hole injection layers 4R, 4G, and 4B having excellent characteristics can be obtained. That is, the hole injection layer 4B that exhibits excellent characteristics by oxidation is formed in the subpixel 100B, and the hole injection layers 4R and 4G that exhibit excellent characteristics by reducing oxidation are formed in the subpixels 100R and 100G. be able to.

  In particular, as described above, in the light emitting device 100 (hybrid type light emitting device) having the light emitting functional layer 6B which is a common light emitting functional layer, generally, the hole injection layer 4B is required to have excellent hole injecting property. When trying to optimize the constituent materials of the hole injection layers 4R, 4G, and 4B, the constituent materials of the hole injection layers 4R and 4G are liable to deteriorate characteristics due to oxidation. Therefore, when the present invention is applied to such a light emitting device 100, the effect becomes remarkable.

[3]
3-1.
Next, as shown in FIG. 3B, the ink 5 a for forming a hole transport layer is applied from the inkjet head 200 onto the hole injection layers 4 </ b> R and 4 </ b> G in the partition wall 31.

  The ink 5a is obtained by dissolving a constituent material of the hole transport layers 5R and 5G or a precursor thereof (third film forming material) in a solvent or dispersing in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  As described above, the third ink application step of applying the ink 5a, which is the third ink containing the third film-forming material, is performed on the hole injection layers 4R and 4G (second functional layer).

3-2
Thereafter, the ink 5a on the hole injection layers 4R and 4G is dried (desolvent or dedispersion medium) and heated to form the hole transport layers 5R and 5G as shown in FIG. To do.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry at 150 ° C. to 250 ° C. for about 5 to 30 minutes in an oven in a nitrogen atmosphere. Thereby, the flat and excellent hole transport layers 5R and 5G having excellent characteristics can be formed.

As described above, the ink 5a applied on the hole injection layers 4R and 4G is dried and then baked in an inert gas atmosphere to form the hole transport layers 5R and 5G which are the third functional layers. A third firing step is performed.
As described above, the hole transport layers 5R and 5G are formed by the liquid phase process.

  According to such a method of forming the hole transport layers 5R and 5G, since the firing is performed in an inert gas atmosphere, the hole injection layers 4R, 4G, and 4B are reduced from being oxidized, and the hole injection is performed. The hole transport layers 5R and 5G can be formed while maintaining the necessary characteristics of the layers 4R, 4G, and 4B.

[4]
4-1
Next, as shown in FIG. 3 (d), the ink 6 a and 6 b for forming the light emitting functional layer is applied from the ink jet head 200 onto the hole transport layers 5 R and 5 G in the partition wall 31. 5b is applied to the hole injection layer 4B in the partition wall 31.

  The ink 6a is obtained by dissolving the constituent material of the light emitting functional layer 6R or its precursor (third film forming material) in a solvent or dispersing it in a dispersion medium. The ink 6b is obtained by dissolving the constituent material of the light emitting functional layer 6G or its precursor in a solvent or dispersing it in a dispersion medium. The ink 5b is obtained by dissolving the constituent material of the hole transport layer 5B or its precursor in a solvent or dispersing it in a dispersion medium. Examples of the solvent or dispersion medium include various inorganic solvents, various organic solvents, or mixed solvents containing these.

  As described above, this step includes the third ink application step of applying the ink 5b, which is the third ink containing the third film-forming material, on the hole injection layer 4B (first functional layer).

4-2
Thereafter, the inks 6a and 6b on the hole transport layers 5R and 5G and the ink 5b on the hole injection layer 4B are dried (desolvent or dedispersion medium) and heat-treated, as shown in FIG. Thus, the light emitting functional layers 6R and 6G and the hole transport layer 5B are formed.

  Drying can be performed, for example, by standing in an atmospheric pressure or reduced pressure atmosphere, heat treatment, spraying of an inert gas, etc., but after drying under reduced pressure for about 10 minutes to 1 hour in a vacuum state of 5 Pa or less. It is preferable to heat dry at 150 ° C. to 250 ° C. for about 5 to 30 minutes in an oven in a nitrogen atmosphere. Thereby, the light emitting functional layers 6R and 6G and the hole transport layer 5B having flat and excellent characteristics can be formed.

  As described above, this step forms the hole transport layer 5B, which is the third functional layer, by drying the ink 5b applied on the hole injection layer 4B and baking it in an inert gas atmosphere. Including a third firing step.

  As described above, the light emitting functional layers 6R and 6G and the hole transport layer 5B are formed by the liquid phase process. The hole transport layer 5B may not be formed at the same time as the light emitting functional layers 6R and 6G, and may be before or after the light emitting functional layers 6R and 6G are formed.

  According to such a method for forming the hole transport layer 5B, since the firing is performed in an inert gas atmosphere, oxidation of the hole injection layers 4R, 4G, and 4B is reduced, and the hole injection layer 4R is reduced. The hole transport layer 5B can be formed while maintaining the necessary characteristics of 4G and 4B.

[5]
Next, as shown in FIG. 4B, the intermediate layer 7, the light emitting functional layer 6 </ b> B, the electrons are formed on the light emitting functional layers 6 </ b> R and 6 </ b> G and the hole transport layer 5 </ b> B so as to cover the partition wall 31. The transport layer 8, the electron injection layer 9, and the cathode 10 are formed in this order.

  The intermediate layer 7, the light emitting functional layer 6 </ b> B, the electron transport layer 8, the electron injection layer 9, and the cathode 10 can be formed by, for example, a vapor phase process using a dry plating method such as vacuum deposition.

[6]
Finally, as shown in FIG. 4C, the cathode 10 is bonded to the sealing substrate 40 via the resin layer 32 (sealing layer). Thereby, the light emitting device 100 is obtained.

  As described above, the hole transport layers 5R, 5G, and 5B and the light emitting functional layers 6R and 6G are individually formed for each element by using a liquid phase process, and the intermediate layer 7 and light emission are formed by using a gas phase process. The functional layer 6B is formed in common to the light emitting elements 1R, 1G, and 1B, respectively, and the light emitting elements 1R, 1G, and 1B can be efficiently manufactured.

  In particular, since the hole injection layer 4B is formed by firing in an oxygen gas atmosphere and then the hole injection layers 4R and 4G are formed by firing in an inert gas atmosphere, the constituent material of the hole injection layer 4B ( Excellent characteristics when the first film-forming material is a material whose characteristics are improved by oxidation and the constituent material (second film-forming material) of the hole injection layers 4R and 4G is a material whose characteristics are deteriorated by oxidation. Can be obtained. Therefore, the light emitting device 100 having excellent characteristics can be manufactured.

Second Embodiment
Next, a second embodiment of the present invention will be described.
FIG. 5 is a view for explaining a method of manufacturing a light emitting device according to the second embodiment of the present invention.

  Hereinafter, although 2nd Embodiment of this invention is described, it demonstrates centering around difference with embodiment mentioned above, The description of the same matter is abbreviate | omitted.

  The second embodiment is the same as the first embodiment described above except that the first ink application process is different.

  In the method of manufacturing the light emitting device 100 according to the present embodiment, a circuit board 20 is prepared as shown in FIG. 5A, and a hole injection layer is formed from the inkjet head 200 as shown in FIG. The ink 4a (first ink) is applied on the anode 3B in the partition wall 31 and the ink 4c composed of only the solvent from the inkjet head 200 is applied on the anodes 3R and 3G in the partition wall 31.

  As the solvent constituting the ink 4c, the same solvent or dispersion medium used for the ink 4a can be used.

  Thereafter, the ink 4c on the anodes 3R and 3G and the ink 4a on the anode 3B are dried (desolvent or dedispersing medium) and heated (baked), so that holes are formed as shown in FIG. An injection layer 4B is formed. Here, since the ink 4c coexists when the ink 4a is dried, the drying speed of the ink 4a can be reduced, and the thickness of the hole injection layer 4B obtained can be made uniform. Further, since the ink 4c is composed only of the solvent, it is volatilized and removed at the time of drying.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
FIG. 6 is a cross-sectional view showing a light emitting device (display device) according to a third embodiment of the present invention.

  Hereinafter, the third embodiment of the present invention will be described. The description will focus on differences from the above-described embodiment, and description of similar matters will be omitted.

  The third embodiment is the same as the first embodiment described above, except that the present invention is applied to a light emitting device in which a light emitting functional layer is independent for each pixel region.

  The light emitting device 100A shown in FIG. 6 is the same as the light emitting device 100 of the first embodiment described above except that the light emitting functional layer 6B that is a blue light emitting functional layer is provided only in the sub-pixel 100B and the intermediate layer 7 is omitted. It is the same.

  In other words, the light emitting element 1R (second light emitting element) included in the light emitting device 100A includes the anode 3R (second anode), the hole injection layer 4R (second hole injection layer), and the hole transport on the interlayer insulating film 22. The layer 5R, the light emitting functional layer 6R (second light emitting functional layer), the electron transport layer 8, the electron injection layer 9, and the cathode 10 (second cathode: common cathode) are laminated in this order.

  Similarly, the light emitting element 1G (third light emitting element) included in the light emitting device 100A includes an anode 3G (third anode), a hole injection layer 4G (third hole injection layer), and a hole on the interlayer insulating film 22. The transport layer 5G, the light emitting functional layer 6G (third light emitting functional layer), the electron transport layer 8, the electron injection layer 9, and the cathode 10 (third cathode: common cathode) are laminated in this order.

  In addition, the light emitting element 1B (first light emitting element) included in the light emitting device 100A includes an anode 3B (first anode), a hole injection layer 4B (first hole injection layer), and hole transport on the interlayer insulating film 22. The layer 5B, the light emitting functional layer 6B (first light emitting functional layer), the electron transporting layer 8, the electron injection layer 9, and the cathode 10 (first cathode: common cathode) are laminated in this order.

  FIG. 6 illustrates the case where the light emitting functional layer 100A has a top emission structure.

  Formation of the hole injection layers 4R, 4G, and 4B of the light emitting device 100A configured as described above can be performed in the same manner as in the step [2] of the method for manufacturing the light emitting device 100 of the first embodiment described above.

(Electronics)
FIG. 7 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 light emitting device 100 described above.

  FIG. 8 is a perspective view showing a configuration of a mobile phone (including PHS) to which the electronic apparatus of the 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 light emitting device 100 described above.

  FIG. 9 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 light emitting device 100 described above.

  A circuit board 1308 is installed inside the case. The circuit board 1308 is provided with a memory that can store (store) an imaging signal.

  A light receiving unit 1304 including an optical lens (imaging optical system), a CCD, and the like is provided on the front side of the case 1302 (on the back side in the illustrated configuration).

  When the photographer confirms the subject image displayed on the display unit and presses the shutter button 1306, the CCD image pickup signal at that time is transferred and stored in the memory of the circuit board 1308.

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

  In addition to the personal computer (mobile personal computer) in FIG. 7, the mobile phone in FIG. 8, and the digital still camera in FIG. 9, the electronic apparatus of the present invention includes, for example, a smartphone, a tablet terminal, a watch, a television, Video camera, viewfinder type, monitor direct-view type video tape recorder, laptop personal computer, smartphone, tablet terminal, watch, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic Game devices, word processors, workstations, videophones, crime prevention TV monitors, electronic binoculars, POS terminals, devices equipped with touch panels (for example, cash dispensers and ticket vending machines of financial institutions), medical devices (for example, electronic thermometers, blood pressure monitors, Blood glucose meter, Electronic display device, ultrasonic diagnostic device, display device for endoscope), fish detector, various measuring instruments, instruments (for example, vehicles, aircraft, ship instruments), flight simulator, other various monitors, projectors, etc. The present invention can be applied to a projection type display device.

  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. Production of light-emitting elements (Examples)
<1> First, a transparent glass substrate having a thickness of 0.5 mm was prepared. Next, an ITO electrode (first anode, second anode, and third anode) having a thickness of 100 nm was formed as a pixel electrode of each of the RGB pixels on the substrate by sputtering. Then, after forming an insulating layer composed of an acrylic resin, the insulating layer was patterned using a photolithography method to expose each ITO electrode, thereby forming a partition (a bank having liquid repellency). .
And the board | substrate was immersed in order of acetone and 2-propanol, and ultrasonically cleaned.

  <2> Next, the hole injection layer forming ink for the B pixel is filled in the partition wall of the B pixel by an inkjet method and applied on the ITO electrode, and then dried under reduced pressure at 5 Pa, and then in an oxygen atmosphere ( A hole injection layer (first hole injection layer) having a thickness of 50 nm was formed by heat treatment (baking) in the air.

  Here, a solution in which 10% of diethylene glycol was added to a PEDOT / PSS aqueous dispersion (1.0 wt%) was used as the ink for forming the hole injection layer for the B pixel.

The firing was performed in the air, the firing temperature was 200 ° C., and the firing time was 10 minutes.
Using such an ink, a B pixel hole injection layer having a dopant material content of 10% was formed.

  <3> Next, the hole injection layer forming ink for the RG pixel is filled in the respective partition walls of the RG pixel by the ink jet method and applied on the ITO electrode, and then dried under reduced pressure at 5 Pa, and then the nitrogen atmosphere. A 50 nm-thick hole injection layer (second and third hole injection layers) was formed by heat treatment (baking) below.

  Here, TFB (poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl)-) mixed with 30% of m-MTDATA is used as a hole injection layer forming ink for R pixel and G pixel. diphenylamine)) solution (1.0 wt%) was used.

  The firing was performed in a nitrogen atmosphere, the firing temperature was 180 ° C., and the firing time was 30 minutes.

  Using such an ink, a hole injection layer of R pixel and G pixel having a dopant material content of 10% was formed.

  <4> Next, the ink for forming the hole transport layer is filled in each partition wall of the RG pixel by the ink jet method and applied onto the hole injection layer, and then dried under reduced pressure at 5 Pa, followed by heat treatment ( By baking, a hole transport layer having a thickness of 20 nm was formed.

  Here, a tetramethylbenzene solution containing 0.5 wt% of TFB (poly (9,9-dioctyl-fluorene-co-N- (4-butylphenyl) -diphenylamine)) is used as an ink for forming a hole transport layer. It was. The firing was performed in a glove box filled with nitrogen, the firing temperature was 180 ° C., and the firing time was 30 minutes.

  <5> Next, the light emitting functional layer forming ink is filled in each partition wall of the RG pixel by an ink jet method and applied onto the hole transport layer, and the hole transport layer forming ink is applied to the B pixel. After filling the partition walls by an ink jet method and applying them onto the hole injection layer, this was dried under reduced pressure at 5 Pa, and then subjected to heat treatment (firing), whereby a light emitting functional layer (second, And a hole transport layer having a thickness of 40 nm was formed on the B pixel.

  Here, 4,4′-bis (9-dicarbazoyl) -2,2′-biphenyl (CBP) and bis (2- (9,9-dihexylfluoro) are used as the light emitting functional layer forming ink for the G pixel. A tetralone solution (concentration: 1.0 wt%) in which enyl) -1-pyridine) (acetylacetonato) iridium was mixed at a weight ratio of 90:10 was used. As an ink for forming a light emitting functional layer for an R pixel, 4,4′-bis (9-dicarbazoyl) -2,2′-biphenyl (CBP) and bis (2- (9,9-dibutylfluoroenyl) -1 -A tetralone solution (concentration: 1.0 wt%) in which isoquinoline) (acetylacetonato) iridium was mixed at a weight ratio of 90:10 was used. As an ink for forming a hole transport layer for B pixels, a tetralone solution (concentration: 1.0 wt%) of N, N-bis (1-naphthalenyl) -N—N′-bis (phenylbenzidine) (α-NPD) is used. Using.

  Moreover, drying was performed by drying under reduced pressure for 10 minutes at a vacuum degree of 5 Pa or less. The firing was performed in a glove box filled with nitrogen, the firing temperature was 100 ° C., and the firing time was 20 minutes.

  <6> Next, a light emitting functional layer forming material (first light emitting functional layer) having a thickness of 20 nm was formed by depositing a material for forming a light emitting functional layer across RGB pixels by vapor deposition.

  Here, the light emitting functional layer forming material is styryl derivative compound 4,4′-bis (2,2-diphenyl-ethen-1-yl) biphenyl (DPVBi) and anthracene derivative compound 6-methyl-2 -(4- (9- (4- (6-Methylbenzo [d] thiazol-2-yl) phenyl) anthracen-10-yl) phenyl) benzo [d] thiazole (DBzA) was mixed in a 97: 3 ratio. Is.

<7> Next, Alq ₃ was deposited on the second light emitting functional layer by a vacuum deposition method to form an electron transport layer having a thickness of 20 nm.

  <8> Next, on the electron transport layer, lithium fluoride (LiF) was formed into a film by a vacuum evaporation method to form an electron injection layer having a thickness of 0.5 nm.

<9> Next, Al was formed into a film by the vacuum evaporation method on the electron injection layer. Thereby, a cathode having a thickness of 150 nm made of Al was formed.
Through the above steps, a light emitting device having RGB pixels (first to third light emitting elements) was manufactured.

(Comparative Example 1)
A light emitting device was manufactured in the same manner as in the above example except that the hole injection layer of the RG pixel was fired in the air.

(Comparative Example 2)
A light emitting device was manufactured in the same manner as in the above-described example except that the hole injection layer of the B pixel was baked in a nitrogen gas atmosphere.

2. Evaluation For each of the examples and comparative examples, a constant current was continuously supplied to the light emitting elements of each pixel using a direct current power source at a current density such that the initial luminance was a predetermined set value, while the luminance was measured using a luminance meter. Measurement was performed, and the time (LT50) during which the luminance was 50% of the initial luminance was measured. Then, the LT50 time of the light emitting element of each pixel in the example was normalized to 1.00, and the LT50 time of the corresponding light emitting element of each pixel was relatively evaluated.
The evaluation results are shown in Table 1.

  As can be seen from Table 1, the light emitting device of the example can have a longer life than the light emitting device of the comparative example.

DESCRIPTION OF SYMBOLS 1 ... Light emitting element 1B ... Light emitting element 1G ... Light emitting element 1R ... Light emitting element 3 ... Anode 3B ... Anode 3G ... Anode 3R ... Anode 4B ... Hole injection layer 4G ... Hole injection layer 4R ... hole injection layer 4a ... ink 5B ... hole transport layer 5G ... hole transport layer 5R ... hole transport layer 5a ... ink 5b ... ink 6B ... light emitting functional layer 6G ... light emission Functional layer 6R ... Light emitting functional layer 6a ... Ink 6b ... Ink 7 ... Hole transport layer 8 ... Electron transport layer 9 ... Electron injection layer 10 ... Cathode 20 ... Circuit board 21 ... Substrate 22 ... Interlayer insulation film 23 Switching element 24 Wiring 31 Partition 32 Resin layer 40 Sealing substrate 100 Light emitting device 100R Subpixel 100G Subpixel 100B Subpixel 200 Inkjet head 231 Semiconductor layer 232 Gate Edge layer 233 ... Gate electrode 234 ... Source electrode 235 ... Drain electrode 1100 ... Personal computer 1102 ... Keyboard 1104 ... Main unit 1106 ... Display unit 1200 ... Mobile phone 1202 ... Operation button 1204 ... Received call Mouth 1206 ... Mouthpiece 1300 ... Digital still camera 1302 ... Case 1304 ... Light receiving unit 1306 ... Shutter button 1308 ... Circuit board 1312 ... Video signal output terminal 1314 ... I / O terminal 1430 ... TV monitor 1440 Personal computer

Claims (11)

A first ink application step of applying a first ink containing a first film-forming material to the first pixel region;
A first firing step of forming a first functional layer by drying the first ink applied to the first pixel region, followed by firing in an oxygen gas atmosphere;
A second ink application step of applying a second ink containing a second film-forming material to a second pixel area different from the first pixel area;
And a second firing step of forming a second functional layer by firing in an inert gas atmosphere after drying the second ink applied to the second pixel region. Device manufacturing method.   The method for manufacturing a light emitting device according to claim 1, wherein each of the first functional layer and the second functional layer is a hole injection layer.   The method for manufacturing a light emitting device according to claim 1, wherein a firing temperature in the first firing step is equal to or higher than a firing temperature in the second firing step.   The method for manufacturing a light-emitting device according to claim 1, wherein the first film-forming material and the second film-forming material are different from each other. The light emitting device
A first anode provided in the first pixel region;
A second anode provided in a second pixel region different from the first pixel region;
A common cathode provided in common to the first pixel region and the second pixel region;
A first light emitting functional layer provided between the first anode, the second anode, and the common cathode in common with the first pixel region and the second pixel region, and having a function of emitting light in a first color; ,
A second light emitting functional layer provided between the first light emitting functional layer and the second anode and having a function of emitting light in a second color different from the first color;
A first hole injection layer provided between the first light emitting functional layer and the first anode;
A second hole injection layer provided between the second light emitting functional layer and the second anode,
The first hole injection layer is the first functional layer;
The method for manufacturing a light emitting device according to claim 1, wherein the second hole injection layer is the second functional layer. A third anode provided in a third pixel region different from the first pixel region and the second pixel region;
The common cathode provided in common in the first pixel region, the second pixel region, and the third pixel region;
The first anode, the second anode, and the first anode provided between the third anode and the common cathode in common with the first pixel region, the second pixel region, and the third pixel region. A light emitting functional layer;
A third light emitting functional layer provided between the first light emitting functional layer and the third anode and having a function of emitting light in a third color different from the first color and the second color;
A third hole injection layer provided between the third light emitting functional layer and the third anode,
The method for manufacturing a light emitting device according to claim 5, wherein each of the second hole injection layer and the third hole injection layer is the second functional layer.   The method for manufacturing a light emitting device according to claim 6, wherein the first color is blue, the second color is red, and the third color is green. A third ink application step of applying a third ink containing a third film-forming material on the first functional layer or the second functional layer;
A third firing step of forming a third functional layer by drying the third ink applied on the first functional layer or the second functional layer, followed by firing in an inert gas atmosphere; The method for manufacturing a light emitting device according to claim 1, comprising:   The method for manufacturing a light emitting device according to claim 8, wherein the third functional layer is a hole transport layer.   A light-emitting device manufactured using the method for manufacturing a light-emitting device according to claim 1.   An electronic apparatus comprising the light emitting device according to claim 10.

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