JP2012037703A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device that efficiently utilizes external light for power generation and is easy to manufacture.SOLUTION: A display device of the present invention includes: a substrate; at least one solar battery; and at least one organic light-emitting device. The solar battery and the organic light-emitting device are provided on the same plane of the substrate; the solar battery and the organic light-emitting device are electrically connected; and power generated by the solar battery is used to drive the organic light-emitting device.

Description

  The present invention relates to a display device in which a light emitting element and a solar cell are integrated.

  A light-emitting device that combines a light-emitting element and a solar cell as a power generation element has been proposed. In this light-emitting device, power is generated by using light emitted from the element and external light such as sunlight, and power is supplied to the light-emitting element, so that power consumption of an external power source, a battery, and the like can be reduced.

Many devices combining light emitting elements and power generating elements have been proposed (for example, Patent Documents 1, 2, 3, 4, and 5).
For example, Patent Document 1 proposes a composite light-emitting element that uses light emitted from a light-emitting element to generate power using a solar cell. This composite light-emitting element is intended for the photoelectric conversion element to convert only light emitted from the self-light-emitting element into electricity.
Patent Document 2 proposes a composite display device including an integrated thin-film solar cell in which a light emitting element portion and a power generating element portion are stacked, power is generated using light from the outside, and light is emitted from the light emitting element. Yes.
Patent Document 3 proposes an organic electroluminescence light emitting display device in which an organic EL element is disposed on one surface of a transparent substrate and a solar cell is disposed on the other surface of the transparent substrate.
Patent Document 4 discloses an illumination panel in which a light emitter and a solar cell are juxtaposed on separate substrates.
Patent Document 5 discloses a composite light emitting device in which an EL element and a power generation element are juxtaposed on the same substrate.

Japanese Patent Laid-Open No. 11-354773 JP 2002-8851 A JP 2002-6769 A JP-A-60-78477 JP 2005-203239 A

As described above, many devices that combine light emitting elements and power generation elements have been proposed. However, regarding the display device, there is a problem that the use of external light such as sunlight is not sufficient, and the manufacturing process is complicated and it is difficult to produce a fine structure.
An object of the present invention is to provide a display device that can efficiently use external light for power generation and is easy to manufacture.

According to the present invention, the following display device is provided.
1. A substrate, at least one solar cell, and at least one organic light emitting device, wherein the solar cell and the organic light emitting device are on the same surface of the substrate, and the solar cell and the organic light emitting device are electrically A display device that is connected to and uses the electric power generated by the solar cell for driving the organic light emitting element.
2. 2. The display device according to 1, wherein the solar cell is an organic solar cell.
3. 3. The display device according to 2, wherein the organic solar cell is an organic thin film solar cell.
4). 4. The display device according to any one of 1 to 3, wherein the organic light emitting element is an organic electroluminescence element.
5. The display device according to any one of 1 to 4, wherein the substrate is a flexible substrate.
6). The display device according to any one of 1 to 5, wherein the solar cell and the organic light emitting element are produced by a vapor deposition method or a coating method.
7). 7. The display device according to 6, which is produced by a vapor deposition method in a vacuum vapor deposition apparatus from installation of a substrate having a lower electrode to installation of an upper electrode.
8). The display device according to any one of 1 to 7, further comprising a secondary battery that stores electric power generated by the solar battery.
9. The display device according to any one of 1 to 8, which has an external power source and drives the organic light emitting element using electric power supplied from the external power source when necessary.

  In the display device of the present invention, since the light emitting element and the solar cell that is the power generation element (light receiving element) are formed on the same surface, the output of the solar cell by absorption of the light emitting element compared to the case where these elements are stacked. Decline can be prevented. Further, since the light emitting surface and the light receiving surface are on the same surface, the amount of power generated by the solar cell does not decrease even when the display device is installed on an opaque wall surface.

It is the perspective view which showed typically one Embodiment of the display apparatus of this invention, and its partial enlarged view. It is a typical fragmentary sectional view which shows the structure of one Embodiment of the display apparatus of this invention. It is a typical fragmentary sectional view which shows the structure of other embodiment of the display apparatus of this invention. It is a typical fragmentary sectional view which shows the structure of other embodiment of the display apparatus of this invention. It is a conceptual diagram for demonstrating full color display by a 3 color system. It is a conceptual diagram for demonstrating full color display by a color conversion system. It is a conceptual diagram for demonstrating full color display by a color filter system. It is a schematic diagram which shows the example of the arrangement | sequence of an organic light emitting element and a solar cell. It is a schematic diagram which shows the example of the arrangement | sequence of an organic light emitting element and a solar cell. It is a schematic diagram which shows the example of the arrangement | sequence of an organic light emitting element and a solar cell. It is the top view which showed typically the composite element which forms the display produced in the Example. It is sectional drawing which showed typically the connection form of the adjacent organic thin film solar cell.

  The display device of the present invention includes a substrate, at least one solar cell, and at least one organic light emitting element. The solar cell and the organic light emitting device are on the same surface of the substrate, the solar cell and the organic light emitting device are electrically connected, and the power generated by the solar cell is used for driving the organic light emitting device. .

FIG. 1 is a perspective view schematically showing an embodiment of a display device of the present invention and a partially enlarged view thereof.
In this embodiment, on the same surface of the substrate 10, the organic light emitting elements 11 that are pixels and the solar cells 12 that are power generation elements are alternately formed. By forming the organic light emitting element 11 and the solar cell 12 on the same surface of the substrate 10, external light such as sunlight can be used efficiently. For example, in the configurations of Patent Documents 1 and 2 described above, since the self-light-emitting element and the photoelectric conversion element are laminated, the light emitted from the self-light-emitting element can be converted into electricity, but external light can be converted into electricity. Could not be converted. In the organic EL display device described in Patent Document 3, an organic EL element is disposed on one surface of a transparent substrate, and a solar cell is disposed on the other surface of the transparent substrate. Therefore, when the organic EL display device is installed in an opaque part such as a wall surface, it is not possible to obtain sufficient power to drive the organic EL element.

  On the other hand, in the present invention, the organic light emitting element 11 and the solar cell 12 are formed on the same surface of the substrate 10, so that there is nothing to block external light incident on the solar cell. Therefore, external light can be used efficiently. Further, even when the display device is used while being hung on an opaque wall, the solar cell 12 is formed on the display surface, so that the amount of power generation is not reduced by the wall. Further, in the above case where the room light is used as the light source of the solar cell, the intensity of the light source is greatly inferior to that of sunlight, but in such a case, the conversion efficiency does not decrease much even if the irradiation light intensity is low as a solar cell. Organic thin film solar cells are preferred.

In the display device of the present invention, it is only necessary that at least one organic light-emitting element and at least one solar cell are formed on the same surface of the substrate, and the position and shape of each element are not particularly limited. Moreover, a well-known thing can be employ | adopted suitably also about an electric circuit.
Hereinafter, an example in which an organic electroluminescence (EL) element is used as the organic light emitting element and an organic thin film solar battery is used as the solar battery will be described.

FIG. 2 is a schematic partial sectional view showing the configuration of an embodiment of the display device of the present invention. For simplification, one organic EL element 11 and one organic thin film solar cell 12 are shown.
In the display device of this embodiment, the organic EL element 11 and the organic thin-film solar battery 12 that is a solar battery are juxtaposed on the same surface of the substrate 10 as the organic light-emitting element.
The organic EL element 11 is configured to have a hole injection layer 11b and an organic light emitting layer 11c between a pair of electrodes, an anode 11a and a cathode 11d. The anode 11 a is formed on the substrate 10. Although depending on the application, the light-emitting pixel size of the organic EL element may be about several tens of μm to 1 cm with a major axis. In mobile applications, such as mobile phones, a small size in the above range and an application such as an advertisement sign having a certain size are considered to be a large size in the above range. Moreover, the structure of an organic EL element is not limited to this embodiment, The structure mentioned later may be sufficient.
The organic thin film solar cell 12 has a configuration in which a p layer 12b and an n layer 12c are formed between a lower electrode 12a and an upper electrode 12d. The lower electrode 12 a is formed on the substrate 10. In addition, the structure of an organic thin film solar cell is not limited to this embodiment, The structure mentioned later may be sufficient. The size of one organic thin film solar cell is preferably slightly larger (3 to 5 times) from the same level as the pixel size of the organic EL element. For example, in accordance with the patterns shown in FIGS. 8 to 10 to be described later, an organic thin-film solar cell having a size slightly larger than the size of the organic EL element, for example, about 1.2 to 3 times, is used. Is preferred. Considering the threshold voltage and light emission efficiency of the organic EL element and the power generation voltage and photoelectric conversion efficiency of the organic thin-film solar cell, one organic EL element pixel corresponds to 2 to 10 solar cells connected in series. Is preferred. A 1: 1 device configuration is also possible by lowering the threshold voltage of the organic EL device and improving the power generation voltage capability of the organic thin-film solar cell.

  The organic thin film solar cell 12 constitutes a power supply unit 20 together with other power supplies and circuits. The organic EL element 11 has an input terminal 13 in order to input power supplied from the power supply unit 20 to the electrode of the organic EL element 11. By electrically connecting the power supply unit 20 and the organic EL element 11, the power generated by the organic thin film solar cell 12 is used to drive the organic EL element 11. In addition, as described above, it is preferable that one organic EL element is made to correspond to a plurality of solar cells from the relationship of driving voltage. However, when power is supplied from the outside, there is no such problem. The ratio between the element and the solar cell can be freely adjusted.

In the present invention, the power supply unit 20 includes at least a solar battery, but may have other power supply elements.
FIG. 3 is a schematic partial cross-sectional view showing the configuration of another embodiment of the display device of the present invention. In the display device according to the present embodiment, the secondary battery 21 is provided in the power supply unit 20. Since the other configuration is the same as that of FIG. 2 described above, description thereof is omitted. In the present embodiment, the organic thin film solar cell 12 is configured to charge the secondary battery 21, and the secondary battery 21 supplies power to the organic EL element 11. As the secondary battery, for example, a lithium ion battery capable of obtaining a high voltage is preferable.

FIG. 4 is a schematic partial cross-sectional view showing the configuration of another embodiment of the display device of the present invention.
In the display device of FIG. 4, a secondary battery 21, an external power supply 22, and a switch 23 are formed in the power supply unit 20. Since the other configuration is the same as that of FIG. 2 described above, description thereof is omitted. In the present embodiment, the organic thin film solar cell 12 charges the secondary battery 21. In addition, the power source of the organic EL element 11 can be selected from the external power source 22 and the secondary battery 21 by the switch 23. With such a configuration, for example, when the charge amount of the secondary battery 21 is sufficient, the organic EL element 11 can be driven using the secondary battery 21. On the other hand, when the charge amount of the secondary battery 21 is insufficient, the organic EL element 11 can be driven using the external power source 22. The selection of the external power source 22 and the secondary battery 21 can be automatically controlled by a known control means. For example, the switch 23 can be controlled by monitoring the charge amount of the secondary battery 21. The output of the driving power supply can be controlled by a driving circuit and supplied to each pixel of the organic EL element to obtain a high-definition display. In this case, the driving method includes an active matrix type in which a transistor and a capacitor are incorporated in each pixel, or a passive matrix type in which a pixel column is driven in a line sequential manner and a driving circuit is provided outside the pixel. Although depending on the application, a passive matrix circuit is preferable in terms of productivity of the display device.

The display device of the present invention is not limited to the above embodiment, and for example, various sensors may be used for controlling the device, or a control unit for driving the display device may be included.
For example, an illuminance sensor is installed in the display device, the brightness of the spot is taken in, the brightness is adjusted by changing the value of the current that is passed through the organic EL element according to the usage environment, and switching on and off can do. Specifically, when the display device is used in a dark place, the brightness of the device can be lowered, and when the display device is used in a bright place, the visibility can be improved by increasing the brightness.

  As the members and materials constituting the display device of the present invention, those known in the technical field of each component can be used. Hereinafter, each component will be briefly described.

1. Substrate The substrate preferably has mechanical and thermal strength and transparency. For example, there are a glass substrate and a transparent resin film. Transparent resin films include polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polypropylene, polystyrene, polymethyl methacrylate, polyvinyl chloride, polyvinyl alcohol, polyvinyl butyral, nylon, polyether ether ketone. , Polysulfone, polyethersulfone, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, polyvinyl fluoride, tetrafluoroethylene-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, polychlorotrifluoroethylene, Polyvinylidene fluoride, polyester, polycarbonate, polyurethane, polyimide, polyetherimide, polyimide, polypropylene, etc. It is.
In the present invention, even a flexible substrate such as a transparent resin film can be used as a substrate for a display device.

2. Solar cell There is no limitation in particular as a solar cell used by this invention, A well-known solar cell is employable. For example, a silicon-based solar cell typified by single crystal Si, polycrystalline Si, amorphous Si, or the like, a multi-component compound semiconductor (Cu (Cu), indium (In), gallium (Ga), and selenium (Se). Examples include CIGS solar cells and organic solar cells using a thin film (CIGS thin film) of In, Ga) Se ₂ ).
Among the above solar cells, an organic solar cell, particularly an organic thin film solar cell is preferable. Since the organic thin film solar cell can be produced by the same method as the organic EL element, the production of the display device can be greatly simplified.
Hereinafter, an organic thin film solar cell will be described as an example of the solar cell.

The cell structure of the organic thin film solar cell is not particularly limited as long as it includes one or more organic thin film layers between a pair of electrodes. If necessary, a buffer layer may be provided between the electrode and the organic layer. Specifically, a structure having the following configuration on a stable insulating substrate can be given.
A. Lower electrode / p layer / laminated i layer (mixed layer of p material and n material) / n layer / upper electrode Lower electrode / buffer layer / p layer / laminated i layer (mixed layer of p material and n material) / n layer / upper electrode c. Lower electrode / p layer / stacked i layer (mixed layer of p material and n material) / n layer / buffer layer / upper electrode d. Lower electrode / buffer layer / p layer / laminated i layer (mixed layer of p material and n material) / n layer / buffer layer / upper electrode and the structure in which the p layer and n layer having the above-mentioned structures a to d are replaced. It is done. What is necessary is just to install a laminated i layer suitably as needed.

In any of the configurations, it is preferable that after the formation of the upper electrode, it is produced by shielding from the lower electrode to the upper electrode without being exposed to the atmosphere, and further, a sealing structure for providing oxidation resistance is provided. As a sealing structure, if it is on a glass substrate, a counterbore glass (glass having a concave portion at the center) is sealed in a nitrogen atmosphere by adding a desiccant to the concave portion and joining the solar cell to the substrate. Or a method of laminating a gas barrier resin after forming an inorganic passivation film around the organic solar cell.
The sealing is preferably performed on the structure in which both the solar cell and the organic EL element are manufactured from the viewpoint of the manufacturing efficiency of the display device.

(1) Lower electrode, upper electrode The material of the lower electrode and the upper electrode is not particularly limited, and a known conductive material can be used. For example, a metal such as tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), gold (Au), palladium (Pd), or the like can be used as an electrode connected to the p layer. As an electrode connected to the n layer, metals such as silver (Ag), aluminum (Al), indium (In), calcium (Ca), platinum (Pt), lithium (Li), Mg: Ag, Mg: In Alternatively, a binary metal system such as Al: Li can be used.
In order to obtain highly efficient photoelectric conversion characteristics, it is desirable that at least one surface of the organic solar cell be sufficiently transparent in the sunlight spectrum. The transparent electrode is formed using a known conductive material so as to ensure predetermined translucency by a method such as vapor deposition or sputtering. The light transmittance of the electrode on the light receiving surface is preferably 10% or more. Furthermore, 50% or more is preferable. In a preferred configuration of the pair of electrode configurations, one of the electrode portions includes a metal having a high work function, and the other includes a metal having a low work function.

(2) p layer, n layer, i layer Typical film thicknesses of the p layer, n layer, and i layer are 5 nm to 1 μm. Particularly preferable film thicknesses are 20 nm to 100 nm, 10 nm to 100 nm, and 10 nm to 1 μm for the p layer, the n layer, and the i layer, respectively.
The material of the p layer is not particularly limited, but a compound having a function as a hole acceptor is preferable. Examples of organic compounds include N, N′-bis (3-tolyl) -N, N′-diphenylbenzidine (mTPD), N, N′-dinaphthyl-N, N′-diphenylbenzidine (NPD) and 4 , 4 ′, 4 ″ -tris (phenyl-3-tolylamino) triphenylamine (MTDATA) and the like, phthalocyanine (Pc), copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc) and titanyl phthalocyanine ( Phthalocyanines such as TiOPc), porphyrins typified by octaethylporphyrin (OEP), platinum octaethylporphyrin (PtOEP) and zinc tetraphenylporphyrin (ZnTPP), and polymer compounds such as polyhexylthiophene (P3HT) And methoxyethylhexyloxyphe Examples thereof include main chain conjugated polymers such as nylene vinylene (MEHPPV), and side chain polymers represented by polyvinyl carbazole.

The material of the n layer is not particularly limited, but a compound having a function as an electron acceptor is preferable. If organic compounds, for _example, fullerene compounds such as _{C 60,} carbon nanotube, perylene compounds, polycyclic quinone, and quinacridone, the polymeric CN- poly (phenylene - vinylene), MEH-CN-PPV, -CN group or CF ₃ group-containing polymers and poly (fluorene) compounds, and the like. A material having a high electron mobility is preferable, and a material having a low electron affinity is preferable. Thus, a sufficient open-circuit voltage can be realized by combining materials having a small electron affinity as the n layer.
Moreover, if it is an inorganic compound, the inorganic semiconductor compound of an n-type characteristic can be mentioned. Specifically, doping semiconductors and compound semiconductors such as n-Si, GaAs, CdS, PbS, CdSe, InP, Nb ₂ O ₅ , WO ₃ , Fe ₂ O ₃ , titanium dioxide (TiO ₂ ), monoxide Examples include titanium oxide such as titanium (TiO) and dititanium trioxide (Ti ₂ O ₃ ), and conductive oxides such as zinc oxide (ZnO) and tin oxide (SnO ₂ ). You may use combining more than a seed. Preference is given to using titanium oxide, particularly preferably titanium dioxide.

  The mixed i layer is composed of a combination of the electron donating material (p) and the electron accepting material (n), and the material is not particularly limited as described above. The electron donating material (p) or the electron accepting material (n ) Can use any of the above exemplified compounds.

(3) Buffer layer In general, the organic thin film solar cell often has a thin total film thickness, and therefore, the upper electrode and the lower electrode are short-circuited, and the yield of cell fabrication often decreases. In such a case, it is preferable to prevent this by laminating a buffer layer. Also, it is preferable to provide a buffer layer in order to take out the generated current efficiently.
As a preferable compound for the buffer layer, a compound having sufficiently high carrier mobility is preferable so that the short-circuit current does not decrease even when the film thickness is increased. For example, if it is a low molecular compound, the aromatic cyclic acid anhydride represented by NTCDA shown below etc. will be mentioned, and if it is a high molecular compound, poly (3,4-ethylenedioxy) thiophene: polystyrene sulfonate (PEDOT: PSS), polyaniline: camphorsulfonic acid (PANI: CSA), and other known conductive polymers. Note that it is also effective to appropriately use the hole injection / transport material and the electron transport material used in the organic EL element in consideration of the combination with the material used for the p layer or the n layer.

In addition, the buffer layer may have a role of preventing excitons from diffusing to the electrodes and deactivating. Inserting a buffer layer as an exciton blocking layer in this way is effective for improving the efficiency of photoelectric conversion. The exciton blocking layer can be inserted on either the anode side or the cathode side, or both can be inserted simultaneously. In this case, as a preferable material for the exciton blocking layer, for example, a well-known material for a hole barrier layer or a material for an electron barrier layer as an organic EL element material may be mentioned. Any of these materials desirably has a sufficiently large energy difference between the HOMO level and the LUMO level, and the fundamental absorption wavelength is shorter than that of the n material and the p material. Such a material has an exciton energy larger than that of the p material and the n material, and this is a condition that the exciton is confined in the p layer or the n layer.
A preferable material for the hole blocking layer is a compound having a sufficiently large ionization potential, and a preferable material for the electron blocking layer is a compound having a sufficiently small electron affinity. Specifically, bathocuproin (BCP), bathophenanthroline (BPhen), etc., which are known materials for organic EL elements, can be exemplified as the cathode-side hole barrier layer material.

Furthermore, you may use the inorganic semiconductor compound illustrated as said n layer material for a buffer layer. As the p-type inorganic semiconductor compound, CdTe, P-Si, SiC, GaAs, WO ₃ or the like can be used.

3. Organic Light-Emitting Element As the organic light-emitting element used in the present invention, for example, an organic EL element, an organic light-emitting transistor, or the like can be employed.
Especially, since an organic EL element emits light at a low voltage (about 3 V), it is suitable because it is suitable for combination with a solar cell.
Hereinafter, an organic EL element will be described as an example of the organic light emitting element.

The configuration of the organic EL element used in the present invention is not particularly limited, and a known configuration can be adopted. For example, the following configurations are exemplified.
(A) Anode / hole injection transport layer / light emitting layer / electron injection transport layer / cathode (B) Anode / hole injection transport layer / light emitting layer / cathode (C) anode / light emitting layer / electron injection transport layer / cathode ( D) Anode / light emitting layer / cathode (E) Anode / hole injection transport layer / electron barrier layer / light emitting layer / electron injection transport layer / cathode

As the (D) type element configuration, in addition to a mode in which a light emitting component is sandwiched between a pair of electrodes in a single layer form, for example, a light emitting layer may be formed as shown in (F) to (G) below. .
(F) Single layer form in which hole injection / transport component, light emitting component and electron injection / transport component are mixed (G) Single layer form in which hole injection / transport component and light emission component are mixed (H) Luminescent component and electron injection / transport component Mixed single layer form

  The organic EL element used in the present invention is not limited to these element configurations, and each type of element may be provided with a plurality of hole injection / transport layers, light emitting layers, and electron injection / transport layers. it can. In each type of device, a light emitting component between the hole injecting and transporting layer and the light emitting layer, a mixed layer of the hole injecting and transporting component and the light emitting component, and / or between the light emitting layer and the electron injecting and transporting layer. And a mixed layer of electron injecting and transporting components can be provided.

(1) Anode As an anode, it is preferable to use a metal, an alloy, or an electrically conductive compound having a relatively large work function as an electrode material. Examples of the electrode material used for the anode include gold, platinum, silver, copper, cobalt, nickel, palladium, vanadium, tungsten, tin oxide, zinc oxide, ITO (indium tin oxide), polythiophene, and polypyrrole. be able to. These electrode materials may be used alone or in combination. For the anode, these electrode materials can be formed on the substrate by a method such as vapor deposition or sputtering. Further, the anode may have a single layer structure or a multilayer structure. The sheet electrical resistance of the anode is preferably set to several hundred Ω or less, more preferably about 5 to 50 Ω. The thickness of the anode is generally set to about 5 to 1000 nm, more preferably about 10 to 500 nm, although it depends on the material of the electrode substance used.
When extracting light from the anode side, it is necessary to be a transparent electrode. In this case, ITO can be mentioned as a suitable material. When the anode is ITO, it can also be used as a lower electrode of a solar cell. In this case, it is possible to install electrodes on the substrate at the same time, which is preferable in terms of productivity improvement and quality control of the display device.

(2) Hole Injecting and Transporting Layer The hole injecting and transporting layer is a layer containing a compound having a function of facilitating injection of holes from the anode and a function of transporting the injected holes. . The hole injecting and transporting layer is a compound having a hole injecting and transporting function (for example, phthalocyanine derivatives, triarylamine derivatives, triarylmethane derivatives, oxazole derivatives, hydrazone derivatives, stilbene derivatives, pyrazoline derivatives, polysilane derivatives, polyphenylene vinylene and their Derivatives, polythiophene and derivatives thereof, poly-N-vinylcarbazole, polytriarylamine derivatives, etc.) can be used.
These compounds having a hole injecting and transporting function may be used alone or in combination.

  Specific examples of the triarylamine derivative having a hole injecting and transporting function include, for example, 4,4′-bis [N-phenyl-N- (4 ″ -methylphenyl) amino] -1,1′-biphenyl, 4 , 4′-bis [N-phenyl-N- (3 ″ -methylphenyl) amino] -1,1′-biphenyl, 4,4′-bis [N-phenyl-N- (3 ″ -methoxyphenyl) amino ] -1,1′-biphenyl, 4,4′-bis [N-phenyl-N- (1 ″ -naphthyl) amino] -1,1′-biphenyl, 3,3′-dimethyl-4,4′- Bis [N-phenyl-N- (3 ″ -methylphenyl) amino] -1,1′-biphenyl, 1,1-bis [4 ′-[N, N-di (4 ″ -methylphenyl) amino] phenyl ] Cyclohexane, 9,10-bis [N- (4'-methylphen Nyl) -N- (4 ″ -n-butylphenyl) amino] phenanthrene, 3,8-bis (N, N-diphenylamino) -6-phenylphenanthridine, 4-methyl-N, N-bis [4 "4" '-bis [N', N'-di (4-methylphenyl) amino] biphenyl-4-yl] aniline, N, N'-bis [4- (diphenylamino) phenyl] -N, N '-Diphenyl-1,3-diaminobenzene, N, N'-bis [4- (diphenylamino) phenyl] -N, N'-diphenyl-1,4-diaminobenzene, 5,5 "-bis [4- (Bis [4-methylphenyl] amino) phenyl-2,2 ′: 5 ′, 2 ″ -terthiophene, 1,3,5-tris (diphenylamino) benzene, 4,4 ′, 4 ″ -tris (N -Carbazolyl) Trifeni Amine, 4,4 ', 4 "-tris [N, N-bis (4"'-tert-butylbiphenyl-4 ""-yl) amino] triphenylamine, 1,3,5-tris [N- ( 4'-diphenylaminophenyl) -N-phenylamino] benzene and the like.

(3) Light emitting layer The light emitting layer is a layer containing a compound having a function of injecting holes and electrons, a function of transporting them, and a function of generating excitons by recombination of holes and electrons. The light emitting layer is a compound having a light emitting function, for example, an acridone derivative, a quinacridone derivative, a diketopyrrolopyrrole derivative, a polycyclic aromatic compound [for example, rubrene, anthracene, tetracene, pyrene, perylene, chrysene, decacyclene, coronene, tetraphenyl Cyclopentadiene, pentaphenylcyclopentadiene, 9,10-diphenylanthracene, 9,10-bis (phenylethynyl) anthracene, 1,4-bis (9′-ethynylanthenyl) benzene, 4,4′-bis (9 “-Ethynylanthracenyl) biphenyl, dibenzo [f, f] diindeno [1,2,3-cd: 1 ′, 2 ′, 3′-lm] perylene derivatives], triarylamine derivatives (eg, hole injection) Examples of the compound having a transport function include the compounds described above. Organometallic complexes [for example, tris (8-quinolinolato) aluminum, bis (10-benzo [h] quinolinolato) beryllium, zinc salt of 2- (2′-hydroxyphenyl) benzothiazole, zinc of 4-hydroxyacridine Salt, zinc salt of 3-hydroxyflavone, beryllium salt of 5-hydroxyflavone, aluminum salt of 5-hydroxyflavone], stilbene derivative [for example, 1,1,4,4-tetraphenyl-1,3-butadiene, 4 , 4′-bis (2,2-diphenylvinyl) biphenyl, 4,4′-bis [(1,1,2-triphenyl) ethenyl] biphenyl], coumarin derivatives (for example, coumarin 1, coumarin 6, coumarin 7). , Coumarin 30, Coumarin 106, Coumarin 138, Coumarin 151, Coumarin 152, Bear Phosphorus 153, coumarin 307, coumarin 311, coumarin 314, coumarin 334, coumarin 338, coumarin 343, coumarin 500), pyran derivatives (eg DCM1, DCM2), oxazone derivatives (eg Nile Red), benzothiazole derivatives, benzoxazole Derivatives, benzimidazole derivatives, pyrazine derivatives, cinnamic acid ester derivatives, poly-N-vinylcarbazole and derivatives thereof, polythiophene and derivatives thereof, polyphenylene and derivatives thereof, polyfluorene and derivatives thereof, polyphenylene vinylene and derivatives thereof, polybiphenylene vinylene And its derivatives, polyterphenylene vinylene and its derivatives, polynaphthylene vinylene and its derivatives, polythienylene vinylene and its derivatives, etc. Door can be.
Furthermore, a host material and a dopant material for efficiently taking out phosphorescence emission to the outside can be mentioned.

(4) Electron Injection / Transport Layer The electron injection / transport layer is a layer containing a compound having a function of facilitating injection of electrons from the cathode and / or a function of transporting injected electrons. Examples of the compound having an electron injecting function used in the electron injecting and transporting layer include organometallic complexes, oxadiazole derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted fluorenones. Derivatives, thiopyrandioxide derivatives and the like. Examples of the organometallic complex include an organoaluminum complex such as tris (8-quinolinolato) aluminum, an organic beryllium complex such as bis (10-benzo [h] quinolinolato) beryllium, a beryllium salt of 5-hydroxyflavone, 5- Examples thereof include an aluminum salt of hydroxyflavone. An organoaluminum complex is preferable, and an organoaluminum complex having a substituted or unsubstituted 8-quinolinolato ligand is more preferable.
In the organic electroluminescence device of the present invention, a metal fluoride such as LiF or MgF, lithium acetate, lithium propionate, lithium benzoate, etc. is further provided between the electron injection transport layer and the cathode for the purpose of increasing the electron injection efficiency. It is also possible to form an intermediate layer of a lithium salt of the organic compound.

(5) Cathode As the cathode, it is preferable to use a metal, alloy or conductive compound having a relatively small work function as an electrode material. Examples of the electrode material used for the cathode include lithium, lithium-indium alloy, sodium, sodium-potassium alloy, calcium, magnesium, magnesium-silver alloy, magnesium-indium alloy, indium, ruthenium, titanium, manganese, yttrium, and aluminum. , Aluminum-lithium alloys, aluminum-calcium alloys, aluminum-magnesium alloys, and graphite thin films. These electrode materials may be used alone or in combination.
In addition, in the description of the lower electrode and the upper electrode of the solar cell described above, it is preferable in terms of productivity improvement and quality control of the display device to use a material overlapping with the material exemplified for the electrode connected to the n layer. .

Although the manufacturing method of the display apparatus of this invention is not specifically limited, It is preferable to produce an organic light emitting element and a solar cell by the same method. For example, when a vacuum deposition method using a mask is used, the organic solar cell and the organic EL element can be produced continuously and consistently without breaking the vacuum in the vacuum deposition apparatus, and the manufacturing process can be simplified. Further, if an interlayer insulating film is formed in advance on a substrate with ITO, such as in the case of a passive patricks type organic EL display, the labor for applying a mask is reduced and the cost may be reduced. In addition, when a coating method such as an ink jet method is used, a large amount can be manufactured with a simple manufacturing process. In the present invention, the element is preferably formed by a vapor deposition method or a coating method.
Hereinafter, the film forming method of each layer when an organic thin film solar cell and an organic EL element are used will be described.

Formation of each layer of organic thin film solar cell and organic EL element is performed by plasma deposition such as vacuum deposition and sputtering, dry deposition methods such as ion plating, spin coating, dip coating, casting, roll coating, flow coating, ink jet, etc. The wet film-forming method can be applied.
The film thickness of each layer is not particularly limited, but the normal film thickness is suitably in the range of 1 nm to 10 μm.

  In the case of a dry film forming method, a known resistance heating method is preferable, and for forming a mixed layer such as an i layer of a solar cell or a light emitting layer of an organic EL element, for example, formation by simultaneous vapor deposition from a plurality of evaporation sources is performed. A membrane method is preferred. More preferably, the substrate temperature is controlled during film formation.

  In the case of a wet film forming method, a material for forming each layer is dissolved or dispersed in an appropriate solvent to prepare a light-emitting organic solution to form a thin film, and any solvent can be used. For example, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride, tetrachloroethane, trichloroethane, chlorobenzene, dichlorobenzene, chlorotoluene, ether solvents such as dibutyl ether, tetrahydrofuran, dioxane, anisole, methanol, Alcohol solvents such as ethanol, propanol, butanol, pentanol, hexanol, cyclohexanol, methyl cellosolve, ethyl cellosolve, ethylene glycol, hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, hexane, octane, decane, tetralin, Examples include ester solvents such as ethyl acetate, butyl acetate, and amyl acetate. Of these, hydrocarbon solvents or ether solvents are preferable. These solvents may be used alone or in combination. In addition, the solvent which can be used is not limited to these.

In the present invention, in any organic thin film layer, an appropriate resin or additive may be used for improving the film formability and preventing pinholes in the film. Usable resins include polystyrene, polycarbonate, polyarylate, polyester, polyamide, polyurethane, polysulfone, polymethyl methacrylate, polymethyl acrylate, cellulose and other insulating resins and copolymers thereof, poly-N-vinyl. Examples thereof include photoconductive resins such as carbazole and polysilane, and conductive resins such as polythiophene and polypyrrole.
Examples of the additive include an antioxidant, an ultraviolet absorber, and a plasticizer.

  Since the organic light-emitting element and the solar cell constituting the present invention can be produced by a vapor deposition method or a coating method, a fine pattern can be easily produced by a method such as mask vapor deposition. Since the patterning is fine, the organic light emitting element can form a pixel of a display, and even if a solar cell is combined with the display device, the appearance is not impaired. In addition, a sealing process can also seal a solar cell and an organic EL element collectively.

  The display format of the display of the present invention is not particularly limited, and a known format can be adopted in the display device. For example, in the case of full color display, the RGB method can be adopted. Further, the driving method of the light emitting element is not particularly limited, and a passive matrix, an active matrix, or the like can be adopted. When an organic EL element is used as the light emitting element, the following (1) to (3) are known as methods for emitting the three primary colors.

(1) Three-color system Three primary colors are obtained by forming organic EL elements each having red, green, and blue light-emitting layers.
FIG. 5 is a conceptual diagram for explaining full-color display by the three-color method.
In the three-color system, three organic EL elements in which the transparent electrode 31, the light emitting layer, and the back electrode 33 are stacked in this order are arranged on the substrate 10. Each EL element has one of the red light emitting layer 32a, the green light emitting layer 32b, and the blue light emitting layer 32c. In this way, three primary colors are obtained by using organic EL elements that emit different colors.
5 and FIG. 6 and FIG. 7 described later indicate the emission color of each element, R indicates red light, G indicates green light, and B indicates blue light.

(2) Color conversion method By using an organic EL element that emits blue light, blue is converted into green or red by a color conversion layer to obtain three primary colors.
FIG. 6 is a conceptual diagram for explaining full-color display by the color conversion method.
In the color conversion method, on the substrate 10, three organic EL elements in which the transparent electrode 31, the blue light emitting layer 32c, and the back electrode 33 are laminated in this order are juxtaposed. The red pixel emits red light by using a red color conversion layer 34a that converts blue light emission into red light emission. Similarly, the green pixel emits green light by using the green color conversion layer 34b that converts blue light emission into green light emission. The blue pixel emits blue light by using the blue light emitted from the organic EL element as it is. Thus, the three primary colors are obtained by using the color conversion layer. Note that a blue color conversion layer may be provided for a blue pixel as in the case of other color pixels. Thereby, blue color purity can be raised.

(3) Color filter system Using organic EL elements that emit white light and passing through a color filter, red, green, and blue are obtained from white. FIG. 7 is a conceptual diagram for explaining full color display by the color filter system. .
In the color filter method, three organic EL elements in which a transparent electrode 31, a white light emitting layer 35, and a back electrode 33 are stacked in this order are arranged on the substrate 10. The red pixel emits red light by using a color filter 36a that extracts red light emission from white light emission. Similarly, the green pixel emits green light by using a color filter 36b that extracts green light emission from white light emission. The blue pixel emits blue light by using a color filter 36c that extracts blue light emission from white light emission. Thus, the three primary colors are obtained by using the color filter.

  Among the above methods, the three-color method is preferable in that the visibility is good and there is no reduction in the amount of light entering the solar cell by a member such as a color filter.

In the present invention, there is no particular limitation on the way in which the solar cells and the organic light emitting elements as pixels are arranged. 8 to 10 are schematic views showing examples of the arrangement of the organic light emitting element and the solar cell. FIG. 8 shows an example in which one solar cell 12 is formed adjacent to one RGB pattern formed by the organic light emitting element (RGB). As shown in FIG. 8, the solar cells may be arranged in a diagonal line on the display surface, or may be arranged linearly vertically and horizontally.
FIG. 9 shows a form in which solar cells 12 are arranged for a group of a plurality of organic light emitting elements (RGB). As described above, the area and shape of the solar cell may be changed in accordance with the group formed by the organic light emitting elements.
FIG. 10 is an example in which the solar cell 12 is disposed in the vicinity of the boundary between the organic light emitting elements (RGB) so as to surround the periphery of the organic light emitting element.
Thus, there is no restriction | limiting in particular in the shape of an organic light emitting element or a solar cell, and it can set suitably in consideration of the use of a display apparatus, the assumption usage amount of external light, etc.
Although not shown, the organic light emitting element and the solar cell are preferably insulated via an insulating member. A general sealing resin or the like can be used as the insulating member.

In the display device of the present invention, since the light emitting element and the solar cell are formed on the same surface of the substrate, the power generation efficiency of the solar cell can be improved as compared with the case where they are stacked or formed on another surface.
Moreover, an organic light emitting element and a solar cell can be formed in the same process (in-line) by using what can be formed by an application | coating or vapor deposition process as an organic light emitting element and a solar cell. Therefore, the production efficiency is extremely high.
In addition, the organic light-emitting element and the solar cell can be manufactured on a flexible substrate such as a plastic film and can be easily applied to a coating process, so that a display device can be manufactured in a large amount at a low cost.

Example 1
A composite element for forming a display using an organic EL element driven by an organic thin film solar cell was produced.
FIG. 11 is a plan view schematically showing a composite element forming a display.
This composite element has a light emitting element line 40 in which the organic EL elements 11 are linearly arranged and a power generation line 50 in which the organic thin film solar cells 12 are linearly arranged. The organic EL element 11 is formed by using an ITO electrode formed on the substrate 10 as a common lower electrode 41, and an organic layer (not shown) and an upper electrode 42 are laminated on the lower electrode 41 in a 2.5 mm square. Has been. FIG. 11 shows eight organic EL elements. The organic EL element emits blue light.
FIG. 12 is a cross-sectional view schematically showing a connection form of adjacent organic thin film solar cells.
The organic thin film solar cell 12 includes a lower electrode 51 made of ITO, an organic layer 52, and an upper electrode 53 made of aluminum. In the adjacent organic thin film solar cell 12, the lower electrode 51 and the upper electrode 53 are electrically connected, and the entire line of the organic thin film solar cell 12 is connected in series. In FIG. 11, ten organic thin film solar cells are connected. Hereinafter, the manufacturing process will be described.

As the substrate, a substrate having a 150 nm ITO film formed on a glass substrate was used. Sunlight reaches the solar cell through the glass substrate and undergoes photoelectric conversion, and the light emitted from the organic EL element is also extracted outside through the glass substrate.
The portion to be the lower electrode of the organic EL element was formed in a line shape, and the portion to be the lower electrode of the organic thin film solar cell was formed in a 2.5 mm square shape.
The ITO-attached glass substrate was washed with a UV washer manufactured by Oak Manufacturing Co., Ltd. for 30 minutes, then carried into a vacuum deposition apparatus and evacuated to 5 × 10 ⁻⁵ Pa. The layer which forms an organic EL element and an organic thin film solar cell was formed in the board | substrate by mask vapor deposition.

First, an organic layer (p layer, i layer, n layer, buffer layer) of an organic thin film solar cell was formed. Specifically, a mask (outer size 30 mm × 4 mm) opened only in the region for forming the solar cell was set in contact with the substrate so that the film was not formed in the region where the organic EL element was formed.
11 and 12, an organic layer mask 1 capable of forming an organic layer is used to form an indenopyrene-based material as a p layer on the lower electrode at a deposition rate of 0.1 nm / s to 25 nm on the lower electrode, also the indenopyrene material at 0.1 nm / s as the i-layer _was 10nm codeposited a _{C 70} fullerene with 0.1 nm / s. Furthermore, the _{C 70} to 50nm deposited at 0.1 nm / s as the n layer, bathocuproine a (BCP) was 10nm deposited at 0.1 nm / s as a buffer layer.
The indenopyrene-based material was produced by the production method described in WO2010 / 013520.

  Subsequently, organic layers (a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer) of the organic EL element were produced. 11, 4 ′, 4 ″ -tris (phenyl-3-tolylamino) triphenylamine (MTDATA, positive) is formed on the lower electrode using the organic mask 2 opened to form the light emitting element group shown in FIG. Hole injecting material) at 60 nm at 0.1 nm / s, N, N′-dinaphthyl-N, N′-diphenylbenzidine (NPD, hole transporting material) at 20 nm, and anthracene-based host material BH1 And a disityrylarylene-based dopant BD2 were co-deposited so that BD2 was 15% by mass of the light emitting layer (film thickness 40 nm). Further, Alq3 (electron transport material) was formed to a thickness of 10 nm at 0.1 nm / s, and LiF was formed to a thickness of 1 nm at 0.01 nm / s.

Subsequently, the upper electrode of the organic thin film solar cell and the organic EL element was formed by vapor deposition of Al (deposition rate: 0.3 to 0.5 nm / s, film thickness 100 nm).
In the organic thin film solar cell, the upper electrode is deposited on the upper electrode of the buffer layer and on the lower electrode of the adjacent organic thin film solar cell, thereby generating power by connecting each organic thin film solar cell (2.5 mm square) in series. A line was formed. In the organic EL element, it was formed on the organic layer with a 2.5 mm square.
One end of the power generation line and the lower electrode (ITO) of the solar cell are electrically connected to the other end of the power generation line and the upper electrode (Al) of the organic EL element, and the power generated by the power generation line is fed to the organic EL element. A composite element emitting light was produced.
Thereafter, the composite element was sealed with counterbore glass. Sealing was performed by bonding counterbore glass with a UV adhesive in a glove box having a dew point of −100 ° C. and an oxygen concentration of 0.1 ppm.

About the obtained composite element, as a result of irradiating only the solar cell side with the artificial sunlight of the intensity | strength of AM1.5G and 100mW / cm < ² >, the light emission of the organic EL element was confirmed.
When an estimated value of luminance was obtained by bringing a photodiode into close contact with the glass surface, it was 650 cd / m ² .
In addition, about the organic thin film solar cell produced this time, when a single cell was separately produced with the same configuration and evaluated, Voc, Jsc, FF, and conversion efficiency were 0.95 V, 7.5 mA / cm ² , 0, respectively. .67, 4.8%.
The characteristics of the organic EL element produced separately were 7 V, 10 mA / cm ² and 820 cd / m ² for driving voltage, current density and luminance, respectively.

  The display device of the present invention can be suitably used as an output device of various information terminals such as a television, a mobile phone, a personal computer, electronic paper used as an advertising medium or a poster, and the like. It can also be used for display devices such as car stereos, MP3 players, and instrument panels of automobiles and motorcycles.

DESCRIPTION OF SYMBOLS 1 Display apparatus 10 Board | substrate 11, R, G, B Organic light emitting element 12 Solar cell 20 Power supply part 21 Secondary battery 22 External power supply 23 Switch 31 Transparent electrode 32a Red light emitting layer 32b Green light emitting layer 32c Blue light emitting layer 33 Back surface electrode 34a Red Color conversion layer 34b Green color conversion layer 35 White light emitting layer 36a Red color filter 36b Green color filter 36c Blue color filter 40 Light emitting element line 41 Lower electrode 42 Upper electrode 50 Power generation line 51 Lower electrode 52 Organic layer 53 Upper electrode

Claims (9)

A substrate, at least one solar cell, and at least one organic light-emitting element;
The solar cell and the organic light emitting device are on the same surface of the substrate;
A display device in which the solar cell and the organic light emitting element are electrically connected, and the electric power generated by the solar cell is used for driving the organic light emitting element.   The display device according to claim 1, wherein the solar cell is an organic solar cell.   The display device according to claim 2, wherein the organic solar cell is an organic thin-film solar cell.   The display device according to claim 1, wherein the organic light emitting element is an organic electroluminescence element.   The display device according to claim 1, wherein the substrate is a flexible substrate.   The display device according to claim 1, wherein the solar cell and the organic light emitting element are produced by a vapor deposition method or a coating method.   The display device according to claim 6, wherein the display device is manufactured by a vapor deposition method in a vacuum vapor deposition apparatus from installation of a substrate having a lower electrode to installation of an upper electrode.   The display device according to claim 1, further comprising a secondary battery that stores electric power generated by the solar battery.   The display device according to claim 1, comprising an external power supply, and driving the organic light emitting element using electric power supplied from the external power supply when necessary.

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