JP2007251148A - Light-emitting element, light-emitting device, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element capable of low-voltage driving, and having a high luminous efficiency and a high emission luminance, and to provide a light-emitting device and electronic equipment that reduce power consumption and can be manufactured inexpensively. <P>SOLUTION: The light-emitting element has a luminous layer 102 and a layer 103 including a composite material between a first electrode 101 and a second electrode 104. The luminous layer contains a base material and an impurity element, the layer 103 including the composite material contains an organic compound and an inorganic compound, the layer including the composite material is provided to be in contact with the second electrode, and light is emitted when voltage is applied so that the potential of the first electrode is higher than that of the second electrode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting element utilizing electroluminescence. In addition, the present invention relates to a light-emitting device and an electronic device each having a light-emitting element.

  In recent years, display devices in televisions, mobile phones, digital cameras, and the like have been demanded to be flat and thin display devices, and display devices using self-luminous light-emitting elements as display devices to satisfy these requirements. Is attracting attention. One of self-luminous light-emitting elements is a light-emitting element that uses electroluminescence. This light-emitting element is formed by sandwiching a light-emitting material between a pair of electrodes and applying a voltage to the light-emitting element. Light emission can be obtained.

  Such a self-luminous light emitting element has advantages such as higher pixel visibility than a liquid crystal display and no need for a backlight, and is considered to be suitable as a flat panel display element. In addition, it is a great advantage that such a light-emitting element can be manufactured to be thin and light. Another feature is that the response speed is very fast.

  Further, since such a self-luminous light emitting element can be formed into a film shape, surface emission can be easily obtained by forming a large-area element. This is a feature that is difficult to obtain with a point light source typified by an incandescent bulb or LED, or a line light source typified by a fluorescent lamp, and therefore has a high utility value as a surface light source applicable to illumination or the like.

  A light-emitting element using electroluminescence is distinguished depending on whether the light-emitting material is an organic compound or an inorganic compound. Generally, the former is called an organic EL element and the latter is called an inorganic EL element.

Inorganic EL elements are classified into a dispersion-type inorganic EL element and a thin-film inorganic EL element depending on the element structure. The former has a light emitting layer in which particles of a light emitting material are dispersed in a binder, and the latter has a light emitting layer made of a thin film of a fluorescent material. However, the mechanism is common, and light emission can be obtained by collision excitation of the base material or emission center by electrons accelerated by a high electric field. For these reasons, a high electric field is required to obtain light emission from a general inorganic EL element, and it is necessary to apply a voltage of several hundred volts to the light emitting element. For example, although a high-luminance blue light-emitting inorganic EL element required for a full-color display has been developed in recent years, a driving voltage of 100 to 200 V is required (for example, Non-Patent Document 1). For this reason, the inorganic EL element consumes a large amount of power, and it has been difficult to adopt it for a small-sized display such as a mobile phone.
Japanese Journal of Applied Physics, 1999, Vol. 38, p. L1291

  In view of the above problems, an object of the present invention is to provide a light-emitting element that can be driven at a low voltage. Another object is to provide a light-emitting element with high emission efficiency. Another object is to provide a light-emitting element with high emission luminance. Another object is to provide a light-emitting element having a long light emission lifetime. It is another object to provide a light-emitting device and an electronic device with reduced power consumption. It is another object to provide a light-emitting device and an electronic device that can be manufactured at low cost.

  The present inventors have found that the problem can be solved by providing a layer containing a composite material between the electrodes.

  Thus, according to one embodiment of the present invention, a light-emitting layer and a layer including a composite material are provided between a first electrode and a second electrode, and the light-emitting layer includes a base material and an impurity element and includes a composite The layer including the material includes an organic compound and an inorganic compound, and the layer including the composite material is provided in contact with the second electrode, and the potential of the second electrode is higher than the potential of the first electrode. Thus, the light-emitting element can emit light when a voltage is applied.

  In the above structure, an aromatic amine compound, a carbazole derivative, or an aromatic hydrocarbon is preferably used as the organic compound.

  In the above structure, the inorganic compound preferably exhibits an electron accepting property with respect to the organic compound. Specifically, a transition metal oxide is preferable. In particular, an oxide of a metal belonging to Groups 4 to 8 in the periodic table is preferable. More preferably, any of vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide is preferable.

  In the above structure, the base material is zinc sulfide, cadmium sulfide, calcium sulfide, yttrium sulfide, gallium sulfide, strontium sulfide, barium sulfide, zinc oxide, yttrium oxide, aluminum nitride, gallium nitride, indium nitride, zinc selenide, Zinc telluride, calcium sulfide-gallium, strontium sulfide-gallium, barium sulfide-gallium, or the like can be used.

  In the above structure, the impurity element is preferably a metal element serving as a light emission center. Alternatively, a plurality of impurity elements are included, and a metal element serving as a light emission center and fluorine (F), chlorine (Cl), bromine (Br), iodine (I), boron (B), aluminum (Al), Any one of gallium (Ga), indium (In), thallium (Tl), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), nitrogen (N), It is preferably any one of phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). It is preferable that the metal element serving as the emission center is contained at a concentration of 0.05 to 5 atom% with respect to the base material. Examples of the metal element include manganese, copper, samarium, terbium, erbium, thulium, europium, cerium, and praseodymium.

  Alternatively, in the above structure, a plurality of impurity elements are included, and any one of copper, silver, gold, platinum, and silicon, and any of fluorine, chlorine, bromine, iodine, boron, aluminum, gallium, indium, and thallium It is preferable that

  Alternatively, in the above structure, a plurality of impurity elements are included, and any one of copper, silver, gold, platinum, and silicon, lithium, sodium, potassium, rubidium, cesium, nitrogen, phosphorus, arsenic, antimony, and bismuth It is preferable that it is any one of these.

  Alternatively, in the above structure, a plurality of impurity elements are included, and any one of copper, silver, gold, platinum, and silicon, and any of fluorine, chlorine, bromine, iodine, boron, aluminum, gallium, indium, and thallium And any one of lithium, sodium, potassium, rubidium, cesium, nitrogen, phosphorus, arsenic, antimony, and bismuth.

  In the above structure, a barrier layer is preferably provided between the light-emitting layer and the first electrode. By providing the barrier layer, it is possible to suppress the carriers from passing through and to improve the light emission efficiency. The thickness of the barrier layer is preferably 1 to 10 nm. The barrier layer is preferably a metal oxide or a metal nitride. For example, when the barrier layer is formed using a metal oxide constituting the first electrode, it is preferable because the barrier layer can be formed continuously with the first electrode.

  The present invention also includes a light emitting device having the above-described light emitting element. The light-emitting device in this specification includes an image display device, a light-emitting device, or a light source (including a lighting device). Also, a panel in which a light emitting element is formed and a connector, for example, a FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) tape, a printed wiring board on the end of a TAB tape or TCP The light-emitting device also includes a module provided with an IC or an IC (integrated circuit) directly mounted on a light-emitting element by a COG (Chip On Glass) method.

  An electronic device using the light-emitting element of the present invention for the display portion is also included in the category of the present invention. Therefore, an electronic device according to the present invention includes a display portion, and the display portion includes the above-described light emitting element and a control unit that controls light emission of the light emitting element.

  The light-emitting element of the present invention has a layer containing a composite material. Since the layer including the composite material is excellent in carrier injecting property and carrier transporting property, the driving voltage of the light-emitting element can be reduced. In addition, luminous efficiency can be improved. In addition, the emission luminance can be improved. In addition, a light-emitting element with a long emission lifetime can be obtained.

  Further, since the light-emitting device of the present invention includes a light-emitting element that can be driven at a low voltage, power consumption can be reduced. In addition, since a drive circuit with high withstand voltage is unnecessary, a light-emitting device can be manufactured at low cost.

  In addition, since the electronic device of the present invention includes a light-emitting element that can be driven at a low voltage, power consumption can be reduced. In addition, since a driving circuit with high withstand voltage is unnecessary, manufacturing cost of the light-emitting device can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)
In this embodiment mode, a composite material used for the light-emitting element of the present invention will be described. Note that in this specification, the term “composite” means that not only two materials are mixed but also mixed at a molecular level so that charge can be transferred between the materials.

The composite material used in the present invention is a composite material formed by combining an organic compound and an inorganic compound. As the organic compound used for the composite material, various compounds such as an aromatic amine compound, a carbazole derivative, an aromatic hydrocarbon, and a high molecular compound (such as an oligomer, a dendrimer, and a polymer) can be used. Note that the organic compound used for the composite material is preferably an organic compound having a high hole-transport property. Specifically, a substance having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or higher is preferable. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Below, the organic compound which can be used for a composite material is listed concretely.

  For example, as an aromatic amine compound, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4′-bis [N- (3-methylphenyl) ) -N-phenylamino] biphenyl (abbreviation: TPD), 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″- And tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA).

  In addition, by using the organic compound shown below, a composite material having no absorption peak can be obtained in a wavelength region of 450 nm to 800 nm.

  As an aromatic amine contained in a composite material having no absorption peak in a wavelength region of 450 nm to 800 nm, N, N′-di (p-tolyl) -N, N′-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4′-bis [N- (4-diphenylaminophenyl) -N-phenylamino] biphenyl (abbreviation: DPAB), 4,4′-bis (N- {4- [N- (3- Methylphenyl) -N-phenylamino] phenyl} -N-phenylamino) biphenyl (abbreviation: DNTPD), 1,3,5-tris [N- (4-diphenylaminophenyl) -N-phenylamino] benzene (abbreviation) : DPA3B) and the like.

  As a carbazole derivative that can be used for a composite material having no absorption peak in the wavelength region of 450 nm to 800 nm, specifically, 3- [N- (9-phenylcarbazol-3-yl) -N— Phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis [N- (9-phenylcarbazol-3-yl) -N-phenylamino] -9-phenylcarbazole (abbreviation: PCzPCA2), 3 -[N- (1-naphthyl) -N- (9-phenylcarbazol-3-yl) amino] -9-phenylcarbazole (abbreviation: PCzPCN1) can be given.

  In addition, 4,4′-di (N-carbazolyl) biphenyl (abbreviation: CBP), 1,3,5-tris [4- (N-carbazolyl) phenyl] benzene (abbreviation: TCPB), 9- [4- ( N-carbazolyl)] phenyl-10-phenylanthracene (abbreviation: CzPA), 2,3,5,6-triphenyl-1,4-bis [4- (N-carbazolyl) phenyl] benzene, and the like can be used. .

Moreover, as an aromatic hydrocarbon which can be used for a composite material having no absorption peak in a wavelength region of 450 nm to 800 nm, for example, 9,10-di (naphthalen-2-yl) -2-tert-butylanthracene (Abbreviation: t-BuDNA), 9,10-di (naphthalen-1-yl) -2-tert-butylanthracene, 9,10-bis (3,5-diphenylphenyl) anthracene (abbreviation: DPPA), 9, 10-di (4-phenylphenyl) -2-tert-butylanthracene (abbreviation: t-BuDBA), 9,10-di (naphthalen-2-yl) anthracene (abbreviation: DNA), 9,10-diphenylanthracene ( Abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-di (4 Methylnaphthalen-1-yl) anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis [2- (naphthalen-1-yl) phenyl] anthracene, 9,10-bis [2- (naphthalene- 1-yl) phenyl] anthracene, 2,3,6,7-tetramethyl-9,10-di (naphthalen-1-yl) anthracene, 2,3,6,7-tetramethyl-9,10-di ( Naphthalen-2-yl) anthracene, 9,9′-bianthryl, 10,10′-diphenyl-9,9′-bianthryl, 10,10′-di (2-phenylphenyl) -9,9′-bianthryl, 10 , 10′-bis [(2,3,4,5,6-pentaphenyl) phenyl] -9,9′-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11 Tetra (tert- butyl) perylene, and the like. In addition, pentacene, coronene, and the like can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or more and having 14 to 42 carbon atoms.

  Note that the aromatic hydrocarbon that can be used for the composite material having no absorption peak in the wavelength region of 450 nm to 800 nm may have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), 9,10-bis [4- (2,2- Diphenylvinyl) phenyl] anthracene (abbreviation: DPVPA) and the like.

  Alternatively, a high molecular compound such as poly (N-vinylcarbazole) (abbreviation: PVK) or poly (4-vinyltriphenylamine) (abbreviation: PVTPA) can be used.

  As the inorganic compound used for the composite material, a transition metal oxide is preferable. In addition, an oxide of a metal belonging to Groups 4 to 8 in the periodic table is preferable. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron accepting properties. Among these, molybdenum oxide is particularly preferable because it is stable in the air, has a low hygroscopic property, and is easy to handle.

  The composite material described in this embodiment is excellent in hole injecting property and hole transporting property. Also, the conductivity is high. Therefore, carriers can be easily injected from the electrode, and carriers can be efficiently transported to the light emitting layer.

  In addition, since it is possible to make ohmic contact with the electrode, a material for forming the electrode can be selected regardless of the work function.

  In addition, the composite material which does not have an absorption peak can be obtained in the wavelength range of 450 nm-800 nm by selecting the kind of organic compound contained in a composite material. Therefore, the light emitted from the light emitting region can be efficiently transmitted without being absorbed, and the external extraction efficiency can be improved.

  In addition, since a layer including a composite material in which an organic compound and an inorganic compound are combined has high conductivity, an increase in driving voltage can be suppressed even when the layer including the composite material is thickened. Therefore, it is possible to optimize the thickness of the layer including the composite material so that the efficiency of extracting light to the outside is increased while suppressing an increase in driving voltage. In addition, the color purity can be improved by optical design without increasing the driving voltage.

  Note that any method may be used for manufacturing the layer including the composite material regardless of a wet method or a dry method. For example, the layer including the composite material can be manufactured by co-evaporation of the organic compound and the inorganic compound described above. Molybdenum oxide is easy to evaporate in a vacuum and is preferable from the viewpoint of the manufacturing process. Moreover, it can also obtain by apply | coating and baking the solution containing the organic compound and metal alkoxide which were mentioned above.

(Embodiment 2)
In this embodiment mode, a light-emitting material used for the light-emitting element of the present invention and a formation method thereof will be described. Examples of the light-emitting material used in the present invention include a base material and a material composed of at least one impurity element serving as a light emission center. Note that these impurity elements do not include elements constituting the base material.

As a base material used for the light-emitting material, sulfide, oxide, or nitride can be used. That is, a compound containing a Group 2 element and a Group 16 element or a compound containing a Group 12 element and a Group 16 element in the periodic table can be used. Alternatively, a compound containing a Group 3 element and a Group 16 element or a compound containing a Group 13 element and a Group 16 element can be used. Alternatively, a compound containing a Group 3 element and a Group 15 element or a compound containing a Group 13 element and a Group 15 element can be used. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used. Calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium sulfide (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

  As emission centers using inner-shell electronic transitions of metal ions, manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), praseodymium (Pr), or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation.

  Alternatively, a light-emitting material including a first impurity element and a second impurity element can be used as a light-emission center using donor-acceptor recombination.

  As the first impurity element, for example, copper (Cu), silver (Ag), gold (Au), platinum (Pt), silicon (Si), or the like can be used.

  Examples of the second impurity element include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium. (Tl) or the like can be used.

  The luminescent material according to the present invention contains the impurity element in the matrix material by a solid phase reaction, that is, a method in which the matrix material and the impurity element are weighed, mixed in a mortar, and heated and reacted in an electric furnace. For example, the base material, the first impurity element or the compound containing the first impurity element, and the second impurity element or the compound containing the second impurity element are weighed and mixed in a mortar, Heat and fire. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state.

In addition, as an impurity element in the case of using a solid phase reaction, a compound composed of a first impurity element and a second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. Examples of the compound composed of the first impurity element and the second impurity element include copper fluoride (CuF ₂ ), copper chloride (CuCl), copper iodide (CuI), copper bromide (CuBr), and nitride Copper (Cu ₃ N), copper phosphide (Cu ₃ P), silver fluoride (AgF), silver chloride (AgCl), silver iodide (AgI), silver bromide (AgBr), gold chloride (AuCl ₃ ), Gold bromide (AuBr ₃ ), platinum chloride (PtCl ₂ ), or the like can be used.

  Alternatively, a light emitting material containing a third impurity element may be used instead of the second impurity element.

  Examples of the third impurity element include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), nitrogen (N), phosphorus (P), arsenic (As), and antimony. (Sb), bismuth (Bi), or the like can be used.

  The concentration of these impurity elements may be 0.01 to 10 mol% with respect to the base material, and is preferably in the range of 0.1 to 5 mol%.

  As the light-emitting material having high electrical conductivity, the above-described material is used as a base material, and the above-described light-emitting material including the first impurity element, the second impurity element, and the third impurity element is used. it can. The concentration of these impurity elements may be 0.01 to 10 mol% with respect to the base material, and is preferably in the range of 0.1 to 5 mol%.

  Examples of the compound composed of the second impurity element and the third impurity element include lithium fluoride (LiF), lithium chloride (LiCl), lithium iodide (LiI), lithium bromide (LiBr), and sodium chloride. Alkali halides such as (NaCl), boron nitride (BN), aluminum nitride (AlN), aluminum antimonide (AlSb), gallium phosphide (GaP), gallium arsenide (GaAs), indium phosphide (InP), Indium nitride (InAs), indium antimonide (InSb), or the like can be used.

  A light-emitting layer using the above-described material as a base material and using the above-described light-emitting material including the first impurity element, the second impurity element, and the third impurity element requires hot electrons accelerated by a high electric field. Without emitting light. That is, since it is not necessary to apply a high voltage to the light emitting element, a light emitting element that can operate with a low driving voltage can be obtained. In addition, since light can be emitted with a low driving voltage, a light-emitting element with reduced power consumption can be obtained. Further, an element that becomes another light emission center may be included.

  Alternatively, the above-described material can be used as a base material, and a light-emitting material including a light-emitting center using the second impurity element, the third impurity element, and the above-described inner-shell electron transition of a metal ion can be used. In this case, the metal ion serving as the emission center is preferably 0.05 to 5 atom% with respect to the base material. The concentration of the second impurity element is preferably 0.05 to 5 atom% with respect to the base material. The concentration of the third impurity element is preferably 0.05 to 5 atom% with respect to the base material. The light emitting material having such a structure can emit light at a low voltage. Accordingly, a light-emitting element that can emit light at a low driving voltage can be obtained, and thus a light-emitting element with reduced power consumption can be obtained. Further, an element that becomes another light emission center may be included.

  For example, a light emitting material containing ZnS as a base material, Cu as a first impurity element, Cl and Ga as a second impurity element, As as a third impurity element, and Mn as another light emission center may be used. Is possible. In order to form such a light emitting material, the following method can be used. Mn is added to a phosphor (ZnS: Cu, Cl) in which copper sulfate (CuS), sulfur, and zinc oxide (ZnO) are blended with ZnS, and is fired in vacuum for about 2 to 4 hours. The firing temperature is preferably 700 to 1500 ° C. The fired product is pulverized to a particle size of 5 to 20 μm, GaAs having a particle size of 1 to 3 μm is added and stirred. A luminescent material can be obtained by baking this mixture at about 500 to 800 ° C. for 2 to 4 hours in a nitrogen stream containing sulfur gas. By using this luminescent material and forming a thin film by vapor deposition or the like, it can be used as a light emitting layer of a light emitting element.

  Further, by adding an impurity element to the above light emitting material, the crystal system of the light emitting material can be controlled. Examples of impurities that can control the crystal system include cubic crystals such as GaP, GaAs, GaSb, InP, InAs, InSb, Si, and Ge. Moreover, GaN and InN can be given as hexagonal ones. Other examples include AlP, AlN, and AlSb. Luminous efficiency can be improved by controlling the crystal system of the light emitting material.

(Embodiment 3)
In this embodiment, one embodiment of a light-emitting element of the present invention will be described with reference to FIGS. In this specification, an EL layer refers to a layer provided between a first electrode and a second electrode.

  In the light-emitting element described in this embodiment, the first electrode 101 and the second electrode 104, the layer 103 containing a composite material in contact with the second electrode 104, the first electrode 101, The element structure includes the light-emitting layer 102 between the layer 103 including the composite material. The light-emitting element described in this embodiment can emit light by applying voltage between the first electrode 101 and the second electrode 104; however, in this embodiment, the light-emitting element has a potential higher than that of the first electrode. A case where light emission is obtained when the potential of the second electrode is increased will be described.

  The substrate 100 is used as a support for the light emitting element. As the substrate 100, for example, glass or plastic can be used. Note that other materials can be used as long as they function as a support of the light-emitting element in the manufacturing process of the light-emitting element.

  As the first electrode 101, various metals, alloys, conductive compounds, mixtures thereof, and the like can be used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by sputtering. For example, indium oxide-zinc oxide (IZO) can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Further, indium oxide (IWZO) containing tungsten oxide and zinc oxide is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. be able to. In addition, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt ( Co), copper (Cu), palladium (Pd), titanium (Ti), titanium nitride (TiN), or the like can be used. Note that in the case where the first electrode 101 or the second electrode 104 is a light-transmitting electrode, the thickness is about 1 nm to 50 nm, preferably about 5 nm to 20 nm, even if the material has low visible light transmittance. By forming the film, it can be used as a translucent electrode. In addition to sputtering, an electrode can also be produced using vacuum deposition, CVD, or a sol-gel method.

  The light-emitting layer 102 is a layer including the light-emitting material described in Embodiment 2 and can be formed using various methods. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

  For the layer 103 including a composite material, the composite material described in Embodiment 1 can be used. Note that in the case where the light-emitting layer 102 and the layer 103 including a composite material are formed by an evaporation method, it is preferable that the light-emitting layer 102 and the layer 103 including a composite material can be continuously formed in a vacuum, so that contamination of the layer interface can be prevented.

  As the second electrode 104, various metals, alloys, conductive compounds, mixtures thereof, and the like can be used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by sputtering. For example, indium oxide-zinc oxide (IZO) can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Further, indium oxide (IWZO) containing tungsten oxide and zinc oxide is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. be able to. In addition, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt ( Co), copper (Cu), palladium (Pd), titanium (Ti), titanium nitride (TiN), or the like can be used. Note that in the case where the first electrode 101 or the second electrode 104 is a light-transmitting electrode, the thickness is about 1 nm to 50 nm, preferably about 5 nm to 20 nm, even if the material has low visible light transmittance. By forming the film, it can be used as a translucent electrode. In addition to sputtering, an electrode can also be produced using vacuum deposition, CVD, or a sol-gel method.

  Note that light emission is extracted outside through the first electrode 101 or the second electrode 104; therefore, at least one of the first electrode 101 and the second electrode 104 is a light-transmitting electrode. There is a need.

Although not illustrated, a buffer layer may be provided between the light-emitting layer and the layer containing the composite material or between the light-emitting layer and the electrode. This buffer layer has a role of facilitating carrier injection and a role of suppressing mixing of both layers. The buffer layer is not particularly limited. For example, ZnS, ZnSe, ZnTe, CdS, SrS, BaS, or the like, which is the base material of the light emitting layer, or CuS, Cu ₂ S, or LiF that is an alkali halide is used. CaF ₂ , BaF ₂ , MgF ₂ or the like can be used.

  Note that FIG. 1A illustrates a structure in which the first electrode 101 is provided on the substrate 100 side; however, layers are stacked in the reverse order of FIG. 1A and illustrated in FIG. As described above, the second electrode 104 may be provided on the substrate 100 side.

  The light-emitting element of the present invention has a layer containing a composite material. Since the layer including the composite material is excellent in carrier injecting property and carrier transporting property, the driving voltage of the light-emitting element can be reduced. In addition, luminous efficiency can be improved.

  In addition, many base materials of light-emitting materials exhibit properties as n-type semiconductors. Therefore, by using a composite material that functions as a p-type semiconductor, carrier injectability is improved. Moreover, luminous efficiency is improved. In addition, light emission caused by electrons and holes can be obtained.

Note that this embodiment can be combined with any of the other embodiments as appropriate.
(Embodiment 4)
In this embodiment, one embodiment of a light-emitting element of the present invention, which is different from that in Embodiment 3, will be described with reference to FIGS.

  The light-emitting element described in this embodiment includes a first electrode 201, a second electrode 205, a layer 204 containing a composite material in contact with the second electrode 205, a first electrode 201, and a substrate 200. The element structure includes the light-emitting layer 203 and the barrier layer 202 between the layer 204 containing the composite material. The light-emitting element described in this embodiment can emit light by applying a voltage between the first electrode 201 and the second electrode 205; however, in this embodiment, the light-emitting element has a potential higher than that of the first electrode. A case where light emission is obtained when the potential of the second electrode is increased will be described.

  The substrate 200 is used as a support for the light emitting element. As the substrate 200, for example, glass or plastic can be used. Note that other materials can be used as long as the light-emitting element functions as a support in the light-emitting element manufacturing process.

  As the first electrode 201, various metals, alloys, conductive compounds, mixtures thereof, and the like can be used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by sputtering. For example, indium oxide-zinc oxide (IZO) can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Further, indium oxide (IWZO) containing tungsten oxide and zinc oxide is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. be able to. In addition, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt ( Co), copper (Cu), palladium (Pd), titanium (Ti), titanium nitride (TiN), or the like can be used. Note that in the case where the first electrode 201 or the second electrode 205 is a light-transmitting electrode, the thickness is about 1 nm to 50 nm, preferably about 5 nm to 20 nm, even if the material has low visible light transmittance. By forming the film, it can be used as a translucent electrode. In addition to sputtering, an electrode can also be produced using vacuum deposition, CVD, or a sol-gel method.

  The barrier layer 202 is a thin film of an insulating material. As the barrier layer 202, an insulating metal oxide or nitride can be used. For example, an oxide or nitride such as aluminum (Al), tungsten (W), chromium (Cr), molybdenum (Mo), or titanium (Ti) can be used.

In the case where the barrier layer 202 is formed after the first electrode 201 is formed, the first electrode 201 is formed of a material that can be anodized, and the surface of the first electrode 201 is anodized so that the barrier layer 202 is formed. Layer 202 can be formed. For example, aluminum is used as the first electrode, and aluminum oxide (Al _x O _y ) can be formed as the barrier layer by anodizing. In addition, by using Ti as the first electrode and anodizing, titanium oxide (TiO _x ) can be formed as the barrier layer. In the case of forming the barrier layer by anodization, it is possible to form a barrier layer in which the film quality (a dense anodized film, a porous anodized film, etc.) is changed depending on the anodizing conditions. In addition, the thickness of the barrier layer can be controlled.

For example, as the electrolytic solution, an ethylene glycol solution of 3% tartaric acid is neutralized with aqueous ammonia and adjusted to PH = 6.92. In this electrolytic solution, platinum is used as the cathode, aluminum as the first electrode is used as the anode, a current is passed between the electrodes at a formation current of 5 to 6 mA and an ultimate voltage of 40 to 100 V, so that the surface of the aluminum film is dense. An anodic oxide film having a strong and strong film quality can be formed. The thickness of the anodized film can be roughly controlled by the applied voltage.

Note that the barrier layer 202 can be formed by a sputtering method, a sol-gel method, or the like other than the above-described anodization.

  The film thickness of the barrier layer 202 is preferably 1 to 10 nm in order to suppress an increase in driving voltage. By providing the barrier layer 202, it is possible to prevent carriers injected into the light emitting layer from passing through the light emitting layer without contributing to light emission and flowing into the electrode. Therefore, light emission efficiency can be improved.

  The light-emitting layer 203 is a layer including the light-emitting material described in Embodiment 2 and can be formed using various methods. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

  For the layer 204 including a composite material, the composite material described in Embodiment 1 can be used. Note that in the case where the light-emitting layer 203 and the layer 204 containing a composite material are formed by a vapor deposition method, it can be formed continuously in a vacuum, which is preferable because contamination of the interface between layers can be prevented.

  As the second electrode 205, various metals, alloys, conductive compounds, mixtures thereof, and the like can be used. Specifically, for example, indium tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), tungsten oxide, and oxide. Examples thereof include indium oxide containing zinc (IWZO). These conductive metal oxide films are usually formed by sputtering. For example, indium oxide-zinc oxide (IZO) can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Further, indium oxide (IWZO) containing tungsten oxide and zinc oxide is formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. be able to. In addition, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt ( Co), copper (Cu), palladium (Pd), titanium (Ti), titanium nitride (TiN), or the like can be used. Note that in the case where the first electrode 201 or the second electrode 205 is a light-transmitting electrode, the thickness is about 1 nm to 50 nm, preferably about 5 nm to 20 nm, even if the material has low visible light transmittance. By forming the film, it can be used as a translucent electrode. In addition to sputtering, an electrode can also be produced using vacuum deposition, CVD, or a sol-gel method.

  However, since light emission is extracted to the outside through the first electrode 201 or the second electrode 205, at least one of the first electrode 201 and the second electrode 205 is a light-transmitting electrode. There is a need.

  Note that FIG. 2A illustrates a structure in which the first electrode 201 is provided on the substrate 200 side; however, layers are stacked in the reverse order to FIG. 2A and illustrated in FIG. As described above, the second electrode 205 may be provided on the substrate 200 side. In the case of the structure illustrated in FIG. 2B, the barrier layer 202 is preferably formed by a sputtering method or a sol-gel method.

  The light-emitting element of the present invention has a layer containing a composite material. Since the layer including the composite material is excellent in carrier injecting property and carrier transporting property, the driving voltage of the light-emitting element can be reduced. In addition, luminous efficiency can be improved.

  In addition, many base materials of light-emitting materials exhibit properties as n-type semiconductors. Therefore, by using a composite material that functions as a p-type semiconductor, carrier injectability is improved. Moreover, luminous efficiency is improved. In addition, light emission caused by electrons and holes can be obtained.

  The light-emitting element described in any of the embodiments includes a barrier layer that is a thin film of an insulating material. By providing the barrier layer, carriers injected into the light emitting layer can be prevented from passing through the light emitting layer without contributing to light emission and flowing into the electrode. Therefore, light emission efficiency can be improved.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 5)
In this embodiment, a mode of a light-emitting element having a structure in which a plurality of light-emitting units according to the present invention is stacked (hereinafter referred to as a stacked element) will be described with reference to FIG. This light-emitting element is a light-emitting element having a plurality of light-emitting units between a first electrode and a second electrode.

In FIG. 14, a first light emitting unit 511 and a second light emitting unit 512 are stacked between a first electrode 501 and a second electrode 502. As the first electrode 501 and the second electrode 502, those similar to those in Embodiments 3 to 4 can be used. The first light-emitting unit 511 and the second light-emitting unit 512 have the same configuration, and the same configurations as those in Embodiments 3 to 4 can be applied. That is, the light-emitting layer and the layer including the composite material are stacked. Further, a structure in which a barrier layer, a light-emitting layer, and a layer including a composite material are stacked can be used as in Embodiment Mode 4.

The charge generation layer 513 includes a composite of an organic compound and a metal oxide. This composite of an organic compound and a metal oxide is composed of an organic compound and a metal oxide such as V ₂ O ₅ , MoO _3, or WO ₃ . As the organic compound, various compounds such as an aromatic amine compound, a carbazole derivative, an aromatic hydrocarbon, and a high molecular compound (oligomer, dendrimer, polymer, etc.) can be used. As the organic compound, it is preferable to use a hole transporting organic compound having a hole mobility of 1 × 10 ⁻⁶ cm ² / Vs or more. Note that other than these substances, any substance that has a property of transporting more holes than electrons may be used. Since a composite of an organic compound and a metal oxide is excellent in carrier injecting property and carrier transporting property, low voltage driving and low current driving can be realized.

Note that the charge generation layer 513 may be formed by combining a composite of an organic compound and a metal oxide with another material. For example, a layer including a composite of an organic compound and a metal oxide may be combined with a layer including one compound selected from electron donating substances and a compound having a high electron transporting property. Alternatively, a layer including a composite of an organic compound and a metal oxide may be combined with a transparent conductive film.

In any case, the charge generation layer 513 sandwiched between the first light-emitting unit 511 and the second light-emitting unit 512 is formed on one side when a voltage is applied to the first electrode 501 and the second electrode 502. Any device that injects electrons into the light emitting unit and injects holes into the other light emitting unit may be used.

Although the light-emitting element having two light-emitting units has been described in this embodiment mode, the present invention can be similarly applied to a light-emitting element in which three or more light-emitting units are stacked. Like the light-emitting element according to this embodiment, a plurality of light-emitting units are partitioned between a pair of electrodes by an electrically insulating charge generation layer, so that the current density is kept low and the high-luminance region is maintained. A long-life element can be realized. Further, when illumination is used as an application example, the voltage drop due to the resistance of the electrode material can be reduced, so that uniform light emission over a large area is possible. Further, when applied to a display device, a display device which can be driven at a low voltage, consumes low power, and has high contrast can be realized.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 6)
In this embodiment mode, a light-emitting device having a light-emitting element manufactured by applying the present invention will be described.

  In this embodiment, a display device as one embodiment of a light-emitting device will be described with reference to FIGS. FIG. 6 is a schematic configuration diagram showing a main part of the display device.

The substrate 410 is provided with a first electrode 416 and a second electrode 418 extending in a direction crossing the electrode. At least at the intersection between the first electrode 416 and the second electrode 418, an EL layer similar to that described in Embodiment Modes 3 to 5 is provided, so that a light-emitting element is formed. In the display device in FIG. 6, a plurality of first electrodes 416 and second electrodes 418 are arranged, and light-emitting elements to be pixels are arranged in a matrix to form a display portion 414. In this display portion 414, an external circuit can control the potentials of the first electrode 416 and the second electrode 418 to control light emission and non-light emission of each light emitting element, thereby displaying a moving image and a still image. .

In this display device, a signal for displaying an image is applied to each of the first electrode 416 extending in one direction of the substrate 410 and the second electrode 418 intersecting with the first electrode 416 so that the light emitting element emits light and does not emit light. select. That is, the pixel is driven by a simple matrix display device which is exclusively driven by a signal supplied from an external circuit. Since such a display device has a simple configuration, it can be easily manufactured even when the area is increased.

Note that the counter substrate 412 may be provided as necessary, and may be used as a protective member by being provided in accordance with the position of the display portion 414. This can be substituted by applying a resin film or resin material without using a plate-like hard material. The first electrode 416 and the second electrode 418 are drawn out to an end portion of the substrate 410 to form a terminal connected to an external circuit. That is, the first electrode 416 and the second electrode 418 form contacts with the flexible wiring substrates 420 and 422 at the end of the substrate 410. Examples of the external circuit include a power supply circuit, a tuner circuit, and the like in addition to a controller circuit that controls a video signal.

FIG. 7 is a partially enlarged view showing the configuration of the display unit 414. A partition layer 424 is formed on a side end portion of the first electrode 416 formed over the substrate 410. An EL layer 426 is formed on at least the exposed surface of the first electrode 416. The second electrode 418 is provided over the EL layer 426. The second electrode 418 intersects with the first electrode 416 and thus extends over the partition wall layer 424. The partition layer 424 is formed using an insulating material so that a short circuit does not occur between the first electrode 416 and the second electrode 418. In a portion where the partition layer 424 covers the end portion of the first electrode 416, a side end portion of the partition layer 424 is given a gradient so that a step is not steep so as to have a so-called tapered shape. When the partition layer 424 has such a shape, coverage with the EL layer 426 and the second electrode 418 is improved, and defects such as cracks and tears can be eliminated.

FIG. 8 is a plan view of the display portion 414 and shows the arrangement of the substrate 410, the first electrode 416, the second electrode 418, the partition layer 424, and the EL layer 426. The auxiliary electrode 428 is preferably provided in order to reduce resistance loss when the second electrode 418 is formed using an oxide transparent conductive film such as indium tin oxide or zinc oxide. In this case, the auxiliary electrode 428 is preferably formed using a high melting point metal such as titanium, tungsten, chromium, or tantalum, or a combination of a high melting point metal and a low resistance metal such as aluminum or silver.

8A and 9B, cross-sectional views taken along lines AB and CD are shown in FIGS. FIG. 9A is a cross-sectional view in which the first electrodes 416 are arranged, and FIG. 9B is a cross-sectional view in which the second electrodes 418 are arranged. An EL layer 426 is formed at the intersection of the first electrode 416 and the second electrode 418, and a light-emitting element is formed there. The auxiliary electrode 428 illustrated in FIG. 9B is provided over the partition layer 424 so as to be in contact with the second electrode 418. By providing the auxiliary electrode 428 over the partition layer 424, a light-emitting element formed at the intersection of the first electrode 416 and the second electrode 418 is not shielded, so that the emitted light can be used effectively. Can do. Further, the auxiliary electrode 428 can be prevented from being short-circuited with the first electrode 416.

FIG. 9 shows an example in which the color conversion layer 430 is provided on the counter substrate 412. The color conversion layer 430 is for changing the wavelength of light emitted from the EL layer 426 to change the emission color. In this case, light emitted from the EL layer 426 is preferably blue or ultraviolet light with high energy. When the color conversion layer 430 is arranged to convert red, green, and blue, a display device that performs RGB color display can be obtained. Further, the color conversion layer 430 can be replaced with a colored layer (color filter). In that case, the EL layer 426 may be configured to emit white light. The filler 432 fixes the substrate 410 and the counter substrate 412, and may be provided as appropriate.

Further, another structure of the display portion 414 is shown in FIG. In the structure of FIG. 10, the end portion of the first electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided over the insulating layer 953. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (side facing the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is the top side (surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, the EL layer 955 and the second electrode 956 can be formed in a self-aligned manner using the partition layer 954.

In the above, when aluminum, titanium, tantalum, or the like is used for the first electrode 416 and indium oxide, indium oxide-tin oxide (ITO), indium zinc oxide, or zinc oxide is used for the second electrode 418, the counter substrate 412 is used. A display device in which a display portion 414 is formed on the side can be provided. In this case, if a thin oxide film is formed on the surface of the first electrode 416, a barrier layer is formed, and light emission efficiency can be increased by a carrier blocking effect. When indium oxide, indium oxide-tin oxide (ITO), indium zinc oxide, or zinc oxide is used for the first electrode 416 and aluminum, titanium, tantalum, or the like is used for the second electrode 418, a display portion is formed on the substrate 410 side. A display device in which 414 is formed can be obtained. In addition, when both the first electrode 416 and the second electrode 418 are formed using a light-transmitting electrode, a double-sided display device can be obtained.

  Since the light-emitting element emits light at a low voltage in the display device of this embodiment mode, a booster circuit or the like is unnecessary, and the structure of the device can be simplified. Further, since it is not necessary to increase the thickness of the EL layer in the light-emitting element, a thinner display device can be realized.

(Embodiment 7)
In this embodiment mode, a light-emitting device having a light-emitting element manufactured by applying the present invention will be described.

  In this embodiment, an active light-emitting device in which driving of a light-emitting element is controlled by a transistor will be described. In this embodiment, a light-emitting device including a light-emitting element manufactured by applying the present invention to a pixel portion will be described with reference to FIGS. 3A is a top view illustrating the light-emitting device, and FIG. 3B is a cross-sectional view taken along lines A-A ′ and B-B ′ in FIG. 3A. Reference numeral 601 indicated by a dotted line denotes a driving circuit portion (source side driving circuit), 602 denotes a pixel portion, and 603 denotes a driving circuit portion (gate side driving circuit). Reference numeral 604 denotes a sealing substrate, reference numeral 605 denotes a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

  Note that the routing wiring 608 is a wiring for transmitting a signal input to the source side driving circuit 601 and the gate side driving circuit 603, and a video signal, a clock signal, an FPC (flexible printed circuit) 609 serving as an external input terminal, Receives start signal, reset signal, etc. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure will be described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source-side driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are illustrated.

  Note that the source side driver circuit 601 is a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined. The TFT forming the driving circuit may be formed by a known CMOS circuit, PMOS circuit or NMOS circuit. In this embodiment mode, a driver integrated type in which a driver circuit is formed over a substrate is shown; however, this is not necessarily required, and the driver circuit can be formed outside the substrate. Note that the structure of the TFT is not particularly limited. A staggered TFT or an inverted staggered TFT may be used. Further, the crystallinity of a semiconductor film used for the TFT is not particularly limited. An amorphous semiconductor film or a crystalline semiconductor film may be used. Further, the semiconductor material is not particularly limited, and an inorganic compound or an organic compound may be used.

  The pixel portion 602 is formed by a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulator 614 is formed so as to cover an end portion of the first electrode 613. Here, a positive photosensitive acrylic resin film is used. Note that light emission of the light emitting element is controlled by the driving circuit, the switching TFT, and the current control TFT.

  In order to improve the coverage, a curved surface having a curvature is formed at the upper end or the lower end of the insulator 614. For example, when positive photosensitive acrylic is used as a material for the insulator 614, it is preferable that only the upper end portion of the insulator 614 has a curved surface with a curvature radius (0.2 μm to 3 μm). As the insulator 614, either a negative type that becomes insoluble in an etchant by light irradiation or a positive type that becomes soluble in an etchant by light irradiation can be used.

  An EL layer 616 and a second electrode 617 are formed over the first electrode 613. At least one of the first electrode 613 and the second electrode 617 has a light-transmitting property, and light emitted from the EL layer 616 can be extracted to the outside.

  The EL layer 616 includes the layer containing the composite material described in Embodiment 1 and the light-emitting layer described in Embodiment 2.

  Note that various methods can be used for forming the first electrode 613, the EL layer 616, and the second electrode 617. Specifically, chemicals such as resistance heating vapor deposition, vacuum deposition such as electron beam vapor deposition (EB vapor deposition), physical vapor deposition (PVD) such as sputtering, metal organic CVD, hydride transport low pressure CVD, etc. Vapor phase epitaxy (CVD), atomic layer epitaxy (ALE), or the like can be used. In addition, an inkjet method, a spin coating method, or the like can be used. Moreover, you may form using the different film-forming method for each electrode or each layer.

  Further, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Yes. Note that the space 607 is filled with a filler, and may be filled with a sealant 605 in addition to an inert gas (such as nitrogen or argon).

  Note that an epoxy-based resin is preferably used for the sealant 605. Moreover, it is desirable that these materials are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic, or the like can be used as a material used for the sealing substrate 604.

  As described above, a light-emitting device having a light-emitting element manufactured by applying the present invention can be obtained.

  The light-emitting device described in this embodiment includes the light-emitting element described in any of Embodiments 3 to 5. The light-emitting elements described in Embodiments 3 to 5 can operate with a low driving voltage. Moreover, high luminous efficiency can be realized. Thus, a light-emitting device with reduced power consumption can be obtained.

  In addition, since the light-emitting device described in this embodiment does not require a high withstand voltage driver circuit, the manufacturing cost of the light-emitting device can be reduced. In addition, the light emitting device can be reduced in weight and the drive circuit portion can be reduced in size.

(Embodiment 8)
In this embodiment, electronic devices each including the light-emitting device described in any of Embodiments 6 to 7 will be described. An electronic device described in this embodiment includes the light-emitting element described in any of Embodiments 3 to 5. Therefore, since the light-emitting element with reduced driving voltage is included, an electronic device with reduced power consumption can be provided.

  Electronic devices manufactured by applying the present invention include cameras such as video cameras and digital cameras, goggle-type displays, navigation systems, sound reproduction devices (car audio, audio components, etc.), computers, game devices, portable information terminals ( A display capable of playing back a recording medium such as a mobile computer, a mobile phone, a portable game machine or an electronic book) and an image playback apparatus (specifically, Digital Versatile Disc (DVD)) provided with a recording medium and displaying the image. And the like). Specific examples of these electronic devices are shown in FIGS.

  FIG. 4A illustrates a television device according to this embodiment, which includes a housing 9101, a supporting base 9102, a display portion 9103, a speaker portion 9104, a video input terminal 9105, and the like. In this television device, the display portion 9103 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 3 to 5 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9103 including the light-emitting elements has similar features, this television set has no deterioration in image quality and low power consumption. With such a feature, the deterioration compensation function circuit and the power supply circuit can be significantly reduced or reduced in the television device; therefore, the housing 9101 and the support base 9102 can be reduced in size and weight. In the television set according to this embodiment, low power consumption, high image quality, and reduction in size and weight are achieved; therefore, a product suitable for a living environment can be provided.

  FIG. 4B illustrates a computer according to this embodiment, which includes a main body 9201, a housing 9202, a display portion 9203, a keyboard 9204, an external connection port 9205, a pointing mouse 9206, and the like. In this computer, the display portion 9203 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 3 to 5 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9203 including the light-emitting elements has similar features, this computer has no deterioration in image quality and has low power consumption. With such a feature, deterioration compensation functional circuits and power supply circuits can be significantly reduced or reduced in the computer, so that the main body 9201 and the housing 9202 can be reduced in size and weight. Since the computer according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for the environment can be provided. Further, the computer can be carried, and a computer having a display portion that is resistant to external shocks when being carried can be provided.

  FIG. 4C illustrates a mobile phone according to this embodiment, which includes a main body 9401, a housing 9402, a display portion 9403, an audio input portion 9404, an audio output portion 9405, operation keys 9406, an external connection port 9407, an antenna 9408, and the like. including. In this cellular phone, the display portion 9403 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 3 to 5 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9403 including the light-emitting elements has similar features, the cellular phone has no deterioration in image quality and low power consumption. With such a feature, the deterioration compensation functional circuit and the power supply circuit can be significantly reduced or reduced in the mobile phone, so that the main body 9401 and the housing 9402 can be reduced in size and weight. Since the cellular phone according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided. Further, it is possible to provide a product having a display portion that is resistant to external impact when being carried.

  4D illustrates a camera, which includes a main body 9501, a display portion 9502, a housing 9503, an external connection port 9504, a remote control receiving portion 9505, an image receiving portion 9506, a battery 9507, an audio input portion 9508, operation keys 9509, and an eyepiece portion. 9510 etc. are included. In this camera, the display portion 9502 is configured by arranging light-emitting elements similar to those described in Embodiment Modes 3 to 5 in a matrix. The light-emitting element has characteristics that light emission efficiency is high, a driving voltage is low, and a short circuit due to an external impact or the like can be prevented. Since the display portion 9502 including the light-emitting elements has similar features, this camera has no deterioration in image quality and has low power consumption. With such a feature, the deterioration compensation function circuit and the power supply circuit can be significantly reduced or reduced in the camera, so that the main body 9501 can be reduced in size and weight. Since the camera according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided. Further, it is possible to provide a product having a display portion that is resistant to external impact when being carried.

  As described above, the applicable range of the light-emitting device manufactured by applying the present invention is so wide that the light-emitting device can be applied to electronic devices in various fields. By applying the present invention, an electronic device having a display portion with low power consumption and high reliability can be manufactured.

  In addition, a light-emitting device to which the present invention is applied has a light-emitting element with high emission efficiency, and can also be used as a lighting device. One mode in which the light-emitting element to which the present invention is applied is used as a lighting apparatus is described with reference to FIGS.

  FIG. 5 illustrates an example of a liquid crystal display device using the light-emitting device to which the present invention is applied as a backlight. The liquid crystal display device illustrated in FIG. 5 includes a housing 901, a liquid crystal layer 902, a backlight 903, and a housing 904, and the liquid crystal layer 902 is connected to a driver IC 905. The backlight 903 uses the light-emitting device of the present invention, and a voltage is applied to the terminal 906.

  By using the light-emitting device of the present invention as a backlight of a liquid crystal display device, a backlight with high luminance and long life can be obtained, so that the quality as a display device is improved. The light-emitting device of the present invention is a surface-emitting light-emitting device and can have a large area. Therefore, the backlight can have a large area, and a liquid crystal display device can have a large area. Further, since the light emitting element is thin and has low power consumption, the display device can be thinned and the power consumption can be reduced.

  In addition, since the light-emitting device to which the present invention is applied can emit light with high luminance, the light-emitting device can be used as a headlight for automobiles, bicycles, ships, and the like. FIG. 11 shows an example in which the light emitting device to which the present invention is applied is used as a headlight of an automobile. FIG. 11B is an enlarged cross-sectional view of a portion of the headlight 1000 in FIG. In FIG. 11B, the light-emitting device of the present invention is used as the light source 1011. Light emitted from the light source 1011 is reflected by the reflecting plate 1012 and extracted to the outside. As shown in FIG. 11B, light with higher luminance can be obtained by using a plurality of light sources. FIG. 11C illustrates an example in which the light-emitting device of the present invention manufactured in a cylindrical shape is used as a light source. Light emitted from the light source 1021 is reflected by the reflecting plate 1022 and extracted outside.

  FIG. 12 illustrates an example in which the light-emitting device to which the present invention is applied is used as a table lamp which is a lighting device. A table lamp illustrated in FIG. 12 includes a housing 2001 and a light source 2002, and the light-emitting device of the present invention is used as the light source 2002. Since the light-emitting device of the present invention can emit light with high luminance, the hand can be brightly illuminated when performing fine work.

  FIG. 13 illustrates an example in which the light-emitting device to which the present invention is applied is used as an indoor lighting device 3001. Since the light-emitting device of the present invention can have a large area, it can be used as a large-area lighting device. In addition, since the light-emitting device of the present invention is thin and has low power consumption, it can be used as a lighting device with low thickness and low power consumption. As described above, in a room where the light-emitting device to which the present invention is applied is used as an indoor lighting device 3001, the television set according to the present invention as shown in FIG. You can appreciate it. In such a case, since both devices have low power consumption, powerful images can be viewed in a bright room without worrying about electricity charges.

  The lighting device is not limited to those illustrated in FIGS. 11, 12, and 13, and can be applied as various types of lighting devices including lighting of houses and public facilities. In such a case, since the illuminating device according to the present invention has a thin light-emitting medium and thus has a high degree of design freedom, it is possible to provide products with various designs on the market.

4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 8A and 8B each illustrate an electronic device of the invention. 8A and 8B each illustrate an electronic device of the invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting element of the present invention.

Explanation of symbols

100 substrate 101 first electrode 102 light emitting layer 103 layer 104 containing composite material second electrode 200 substrate 201 first electrode 202 barrier layer 203 light emitting layer 204 layer 205 containing composite material second electrode 410 substrate 412 counter substrate 414 Display portion 416 First electrode 418 Second electrode 420 Flexible wiring board 424 Partition layer 426 EL layer 428 Auxiliary electrode 430 Color conversion layer 432 Filler 501 First electrode 502 Second electrode 511 First light emitting unit 512 Second light emitting unit 513 Charge generation layer 601 Source side driving circuit 602 Pixel portion 603 Gate side driving circuit 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (flexible printed circuit)
610 Element substrate 611 TFT for switching
612 Current control TFT
613 First electrode 614 Insulator 616 EL layer 617 Second electrode 618 Light-emitting element 623 n-channel TFT
624 p-channel TFT
901 Case 902 Liquid crystal layer 903 Backlight 904 Case 905 Driver IC
906 Terminal 952 First electrode 953 Insulating layer 954 Partition layer 955 EL layer 956 Second electrode 1000 Headlight 1011 Light source 1012 Reflecting plate 1021 Light source 1022 Reflecting plate 2001 Housing 2002 Light source 3001 Illuminating device 9101 Housing 9102 Support base 9103 Display Unit 9104 speaker unit 9105 video input terminal 9201 main body 9202 housing 9203 display unit 9204 keyboard 9205 external connection port 9206 pointing mouse 9401 main body 9402 housing 9403 display unit 9404 audio input unit 9405 audio output unit 9406 operation key 9407 external connection port 9408 antenna 9501 Main body 9502 Display unit 9503 Housing 9504 External connection port 9505 Remote control receiving unit 9506 Image receiving unit 9507 Battery 9508 Audio input unit 509 operation key 9510 eyepiece

Claims (22)

Between the first electrode and the second electrode, a light emitting layer, and a layer containing a composite material,
The light emitting layer includes a base material and an impurity element that forms a light emission center,
The layer including the composite material includes an organic compound and an inorganic compound,
The layer including the composite material is provided in contact with the second electrode,
The light-emitting element is characterized in that light emission is obtained when voltage is applied so that the potential of the second electrode is higher than the potential of the first electrode. In claim 1,
The light-emitting element, wherein the organic compound is an aromatic amine compound. In claim 1,
The light-emitting element, wherein the organic compound is a carbazole derivative. In claim 1,
The organic compound is an aromatic hydrocarbon. In any one of Claims 1 thru | or 4,
The light-emitting element, wherein the inorganic compound exhibits an electron accepting property with respect to the organic compound. In any one of Claims 1 thru | or 4,
The light-emitting element, wherein the inorganic compound is a transition metal oxide. In any one of Claims 1 thru | or 4,
The light-emitting element, wherein the inorganic compound is an oxide of a metal belonging to Group 4 to Group 8 in the periodic table. In any one of Claims 1 thru | or 4,
The light-emitting element, wherein the inorganic compound is any one of vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. In any one of Claims 1 thru | or 8,
The base material is zinc sulfide, cadmium sulfide, calcium sulfide, yttrium sulfide, gallium sulfide, strontium sulfide, barium sulfide, zinc oxide, yttrium oxide, aluminum nitride, gallium nitride, indium nitride, zinc selenide, zinc telluride, sulfide A light-emitting element characterized by being one of calcium-gallium, strontium sulfide-gallium, and barium sulfide-gallium. In any one of Claims 1 thru | or 9,
The light-emitting element, wherein the impurity element is a metal element serving as a light emission center. In any one of Claims 1 thru | or 9,
The impurity element includes a plurality of types,
A metal element that becomes the emission center;
Any one of fluorine (F), chlorine (Cl), bromine (Br), iodine (I), boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium (Tl);
Of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) One of the light-emitting elements. In claim 9 or claim 10,
The light-emitting element, wherein the metal element is contained at a concentration of 0.05 to 5 atom% with respect to the base material. In any one of Claims 9-12,
The light-emitting element, wherein the metal element is any one of manganese, copper, samarium, terbium, erbium, thulium, europium, cerium, and praseodymium. In any one of Claims 1 thru | or 9,
The impurity element includes a plurality of types,
With one of copper, silver, gold, platinum, silicon,
A light-emitting element which is any one of fluorine, chlorine, bromine, iodine, boron, aluminum, gallium, indium, and thallium. In any one of Claims 1 thru | or 9,
The impurity element includes a plurality of types,
With one of copper, silver, gold, platinum, silicon,
A light-emitting element which is any one of lithium, sodium, potassium, rubidium, cesium, nitrogen, phosphorus, arsenic, antimony, and bismuth. In any one of Claims 1 thru | or 9,
The impurity element includes a plurality of types,
With one of copper, silver, gold, platinum, silicon,
Any one of fluorine, chlorine, bromine, iodine, boron, aluminum, gallium, indium, and thallium;
A light-emitting element which is any one of lithium, sodium, potassium, rubidium, cesium, nitrogen, phosphorus, arsenic, antimony, and bismuth. In any one of Claims 1 thru | or 16,
A light-emitting element, wherein a barrier layer is provided between the light-emitting layer and the first electrode. In claim 17,
The light-emitting element, wherein the barrier layer has a thickness of 1 to 10 nm. In claim 17 or claim 18,
The light emitting device, wherein the barrier layer is a metal oxide or a metal nitride. In claim 17 or claim 18,
The light-emitting element, wherein the barrier layer is an oxide of a metal constituting the first electrode. 21. A light-emitting device comprising: the light-emitting element according to claim 1; and a control unit that controls light emission of the light-emitting element. Having a display,
21. An electronic apparatus comprising: the light emitting element according to claim 1; and a control unit that controls light emission of the light emitting element.

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