JP2018174272A - Organic EL element and organic EL light source - Google Patents

Abstract

An object of the present invention is to provide an organic EL element that has high voltage resistance and allows a large amount of current to flow. An organic EL layer (16), a semiconductor layer (13) in contact with the lower surface side of the organic EL layer, and current control means for controlling current flowing through the organic EL layer, the organic EL layer including a light emitting layer (161), The light-emitting layer includes an organic semiconductor, the semiconductor layer includes a first semiconductor layer 131 and a second semiconductor layer 132, and the current control means includes a gate electrode 11, a gate insulating film 12, and a source electrode 14. , and a drain electrode 15, one of the semiconductor layers is n-type and the other is p-type, the source electrode is in contact with the lower surface side of the semiconductor layer, and the drain electrode is in contact with the upper surface side of the organic EL layer. When the first semiconductor layer is a semiconductor layer containing an inorganic semiconductor, application to the gate electrode forms an inversion layer 133, and when the first semiconductor layer contains an organic semiconductor, the second A third semiconductor layer of a type different from the type of the one semiconductor layer is formed. [Selection drawing] Fig. 1

Description

  The present invention relates to an organic EL element and an organic EL light source.

The organic EL element is expected to be applied to an organic EL display device, a communication device, illumination, and the like. In the organic EL display device, the luminance required for the organic EL element is, for example, about 500 cd / m ² . However, high brightness of 3000 cd / m ² or more is required for applications such as illumination and visible light communication.

  As a method for improving the luminance of the organic EL element, for example, increasing the current for driving the organic EL element can be considered. However, in a general organic EL element, for example, when the current is increased, heat is generated at the time of light emission, and the organic EL element may be deteriorated or destroyed by the heat.

  As described above, a general organic EL element has low voltage resistance and leads to a short circuit / breakage of the element. Therefore, the current density cannot be increased, and it is difficult to improve the luminance per unit area. Therefore, attempts have been made to increase the luminance by increasing the area of the light emitting layer. However, when the area of the light emitting layer is increased, a voltage drop occurs due to an increase in the wiring resistance of the electrode. Since the organic EL element is an electric field injection type, there is a problem that luminance unevenness occurs due to a voltage drop.

  For this reason, there is a demand for an organic EL element having a large voltage tolerance and a structure capable of flowing a large current.

  As an organic EL element having a structure capable of flowing a large current, an organic thin film light-emitting transistor including a gate electrode, a source electrode, three terminals of the gate electrode, an insulator layer, and an organic semiconductor layer is disclosed (Patent Document 1). ). The organic thin film light emitting transistor can control the light emission by causing the organic semiconductor layer to emit light using a source-drain current and applying a voltage to the gate electrode.

JP 2013-58599 A

  An object of the present invention is to provide an organic EL device having a structure that has a higher voltage tolerance and can flow a large current.

In order to achieve the above object, the organic EL device of the present invention comprises:
A substrate, an organic EL layer, a semiconductor layer in contact with the lower surface side of the organic EL layer, and current control means for controlling a current flowing through the organic EL layer,
The organic EL layer includes a light emitting layer,
The light emitting layer includes an organic semiconductor,
The semiconductor layer includes a first semiconductor layer and a second semiconductor layer,
The current control means includes a gate electrode, a gate insulating film, a source electrode, and a drain electrode,
One of the first semiconductor layer and the second semiconductor layer is an n-type semiconductor layer, and the other is a p-type semiconductor layer,
The source electrode is in contact with the lower surface side of the semiconductor layer, the drain electrode is in contact with the upper surface side of the organic EL layer,
The first semiconductor layer is formed so as to cover the source electrode;
The gate electrode is in contact with the source electrode and the first semiconductor layer through the gate insulating film;
When the first semiconductor layer is a semiconductor layer containing an inorganic semiconductor, an inversion layer is formed in the first semiconductor layer by application to the gate electrode,
When the first semiconductor layer is a semiconductor layer including an organic semiconductor, the first semiconductor layer includes a third semiconductor layer, and the third semiconductor layer is a type of the first semiconductor layer. It is characterized by being a semiconductor layer of a different type.

  The organic EL light source of the present invention includes the organic EL element of the present invention.

  According to the present invention, it is possible to provide an organic EL element capable of emitting light with high luminance, for example, by having a higher voltage tolerance and allowing a large current to flow.

FIG. 1 is a cross-sectional view showing an example of the structure of an organic EL element according to Embodiment 1. FIG. 2 is a cross-sectional view showing an example of the structure of the organic EL element in the second embodiment. FIG. 3 is a cross-sectional view and a plan view showing an example of the structure of the organic EL element in the third embodiment. FIG. 4 is a plan view showing an example of the structure of the organic EL element in the fourth embodiment. FIG. 5 is a circuit diagram showing an example of the structure of the organic EL element in the fifth embodiment.

  In the organic EL element of the present invention, for example, the gate electrode is further in contact with the second semiconductor layer through the gate insulating film.

  In the organic EL element of the present invention, for example, the gate electrode, the gate insulating film, the semiconductor layer, and the organic EL layer are stacked in the above order on the substrate.

  In the organic EL device of the present invention, for example, at least one selected from the group consisting of the gate electrode, the source electrode, and the drain electrode is a transparent electrode.

  In the organic EL element of the present invention, for example, the organic EL layer further includes an electron injection layer.

  The organic EL element of the present invention has, for example, a structure in which the gate electrode extends in the planar direction.

  The organic EL element of the present invention has, for example, a structure in which the gate electrode extends perpendicular to the planar direction.

  In the organic EL device of the present invention, for example, the gate electrode has a round shape when viewed from above.

  In the organic EL element of the present invention, for example, the current control unit includes a plurality of the gate electrodes, and the light emitting layer emits a plurality of colors corresponding to the plurality of gate electrodes.

  Next, an embodiment of the present invention will be described with reference to the drawings. The present invention is not limited or restricted by the following embodiments. In the following drawings, the same parts are denoted by the same reference numerals. The description in each embodiment can mutually use each other. Further, in the drawings, for convenience of explanation, there is a portion where the structure of each portion is simplified as appropriate, and the dimensional ratio of each portion may be schematically shown, unlike the actual case.

(Embodiment 1)
FIG. 1 is a cross-sectional view (schematic diagram) of an organic EL element in the present embodiment. As shown in FIG. 1, the organic EL element 1 of this embodiment includes a substrate 10, a gate electrode 11, a gate insulating film 12, a semiconductor layer 13, a source electrode 14, a drain electrode 15, and an organic EL layer. 16, the gate electrode 11, the gate insulating film 12, the semiconductor layer 13, and the organic EL layer 16 are stacked on the substrate 10 in the order described above. In the present embodiment, the source electrode 14 is disposed in contact with the lower surface side of the semiconductor layer 13, and the drain electrode 15 is disposed in contact with the upper surface side of the organic EL layer 16. The semiconductor layer 13 includes an n-type semiconductor layer (first semiconductor layer) 131 and a p-type semiconductor layer (second semiconductor layer) 132, and the n-type semiconductor layer 131 is formed so as to cover the source electrode 14. A p-type semiconductor layer 132 is formed thereon. In the present embodiment, the n-type semiconductor layer 131 is formed of an inorganic semiconductor. In this case, as described later, the inversion layer 133 is formed in the n-type semiconductor layer 131 by applying a voltage to the gate electrode 11. In the present embodiment, the organic EL layer 16 includes a light emitting layer 161 and an electron injection layer 162. The light emitting layer 161 includes an organic semiconductor. In the present embodiment, the electron injection layer 162 has an arbitrary configuration, and may or may not be included in the organic EL element 1.

  In the present invention, the vertical direction is a stacking direction of each member with respect to the substrate 10, the substrate 10 side is a downward direction, and the opposite side to the substrate 10 is an upward direction. Further, the upper surface means an upward surface of the organic EL element.

  In the first embodiment, the semiconductor layer 13 includes an n-type semiconductor layer 131 and a p-type semiconductor layer 132. The n-type semiconductor layer 131 is formed so as to cover the source electrode 14, and a p-type semiconductor is formed thereon. Although the layer 132 is formed, the present invention is not limited to this, and the n-type semiconductor layer and the p-type semiconductor layer may be reversed. In this case, the polarity of the organic EL element 1 is reversed. In the following description, the description about the organic EL element 1 can be similarly applied to the case where the n-type semiconductor layer and the p-type semiconductor layer have opposite configurations.

  In the organic EL element 1, the materials of the gate electrode 11, the gate insulating film 12, the semiconductor layer 13, the source electrode 14, and the drain electrode 15 are not particularly limited, and known materials can be used.

Examples of the material for forming the gate electrode 11 include Al—Nd, Au, Ag, Cu, Mo—Nb, Ta, Cr, and alloys thereof, and ITO, IGZO, IZO, and SnO ₂ . Examples of the material for forming the source electrode 14 and the drain electrode 15 include Al—Nd, Au, Ag, Cu, Al, Mo—Nb, and alloys thereof, and ITO, IGZO, IZO, and SnO _2. It is done. For example, at least one of the gate electrode 11, the source electrode 14, and the drain electrode 15 is preferably formed of a transparent conductive film in order to extract light from the organic EL element 1. An example of the material of the transparent conductive film is ITO. Each of the gate electrode 11, the source electrode 14, and the drain electrode 15 may be a laminated film, for example. The laminated film can be formed, for example, by forming the material into a clad structure of an electrode and a barrier metal.

Examples of the material for forming the gate insulating film 12 include inorganic materials such as SiO ₂ , Si ₃ N ₄ , SiON, Al ₂ O ₃ , and Ta ₂ O ₅ . Further, even if a film formed of the inorganic material is subjected to silane coupling treatment such as HMDS (hexamethyldisilazane) treatment in order to reduce surface energy and improve mobility, for example. Good. Examples of the material for forming the gate insulating film 12 include polyimide resins, acrylic resins, and novolac resins as organic materials.

  In the organic EL element 1, the semiconductor layer 13 includes an n-type semiconductor layer 131 and a p-type semiconductor layer 132. When the n-type semiconductor layer and the p-type semiconductor layer are formed of an organic semiconductor, the material for forming the n-type semiconductor layer is, for example, fullerene such as fullerene C60 and fullerene C70 and derivatives thereof as a low-molecular n-type semiconductor. N, N'-dimethyl-3,4,9,10-perylenetetracarboxylic acid diimide, N, N'-di-n-octyl-3,4,9,10-perylenetetracarboxylic acid diimide, N, N Imides such as ′ -dioctyl-3,4,9,10-perylenedicarboxyldiimide (PTCDI), copper (II) 1,2,3,4,8,9,10,11,15,16,17, Tetracarboxylic acids such as 18,22,23,24,25-hexadecafluorophthalocyanine, naphthalene-1,4,5,8-tetracarboxylic dianhydride, 3,4,9,10-perylenetetracarboxylic acid Anhydrides, tetracyanoquinodimethane (TCNQ) and the like. Examples of the material for forming the n-type semiconductor layer include polythiophenes and polyfluorenes as organic semiconductors using polymers. The material for forming the p-type semiconductor layer is, for example, pentacene, 5,6,11,12-tetraphenylnaphthacene (rubrene), 2,3-benzoanthracene (tetracene), 2 as a low-molecular p-type semiconductor. , 6-diphenylanthracene and other acenes, dinaphtho [3,2-b: 2 ', 3'-f] thieno [3,2-b] thiophene (DNTT), 2,7-diphenyl [1] benzothieno [3 , 2-b] [1] benzothiophene (DPh-BTBT), phenanthro [1,2-b: 8,7-b '] dithiophene, heteroacenes such as benzo [a] chrysene, 2,5-bis (4 -Biphenylyl) thiophene, thiophenes such as 2,8-dimethylanthra [2,3-b: 7,6-b '] dithiophene (DMADT) and oligothiophenes, porphyrins such as phthalocyanine and copper phthalocyanine, Benzothiazoles such as 7-di (2-thienyl) -2,1,3-benzothiadiazole, and bis (ethylenedithio) tetrathiafulva Emissions (TTF), and the like.

  In the case where the n-type semiconductor layer and the p-type semiconductor layer are formed of an inorganic semiconductor, for example, n-doped silicon such as boron can be used as a material for forming the n-type semiconductor layer. As a material for forming the p-type semiconductor layer, for example, p-doped silicon such as phosphorus or arsenic can be used. The n-type semiconductor layer and the p-type semiconductor layer can be formed using a metal oxide semiconductor such as IGZO in addition to the above materials.

  In the organic EL element 1, when the n-type semiconductor layer 131 is formed of an inorganic semiconductor, for example, an inversion layer serving as a p-channel is formed in the n-type semiconductor layer 131 by the gate voltage, and holes flowing in the channel are formed. This is a p-channel transistor for controlling

In the organic EL element 1, the light emitting layer 161 may be, for example, either hole transportable or electron transportable. The material of the light emitting layer 161 is not particularly limited, and a known material can be used. When the light emitting layer 161 has a hole transporting property, examples of the material for forming the light emitting layer 161 include a dibenzochrysene derivative (DBC) and a bis-styrylbenzene derivative (BSB). The light emitting layer 161 may be formed of a binary system of a host and a dopant, and is 4,4′-bis (m-tolylphenylamino) biphenyl (TPD), bis (di (p-tolyl) aminophenyl). Triphenyldiamine derivatives such as -1,1-cyclohexane, N, N′-diphenyl-NN—bis (1-naphthyl) -1,1′-biphenyl) -4,4′-diamine (α-NPD) In which rubrene and BTX are used as dopants, and 4,4′-biscarbazolylbiphenyl (CBP), 4,4′-bis (9-carbazolyl) -2,2′-dimethylbiphenyl ( With a carbazole derivative such as CDBP) as a host, platinum complex, tris- (2-phenylpyridine) iridium complex (Ir (ppy) 3), (bis (4,6-difluorophenyl) Pyridinate-N, C2 ′) picolinate iridium complex (FIr (pic)), (bis (2- (2′-benzo4,5-αthienyl) pyridinate-N, C2 ′) acetylacetonate) iridium complex (Btp2Ir (Acac)), Ir (pic) 3, Bt2Ir (acac) and the like using iridium complexes as dopants. When the light emitting layer 161 is electron transporting, examples of a material for forming the light emitting layer 161 include an aluminum quinolinol complex (Alq ₃ ), 4-methyl-8-hydroxyquinoline (Almq), and a beryllium quinolinol complex (BeBq _2). ), Hydroxyphenyloxazole (ZnPBO), hydroxyphenylthiazole (ZnPBT) 4,4′-bis (2,2-diphenylvinyl) biphenyl (DPVBi), and the like. The light-emitting layer 161 may be formed of a two-component system of a host and a dopant. A quinolinol metal complex such as Alq3 is used as a host, and 4-dicyanomethylene-2-methyl-6- (p-dimethylaminostyryl)- 4H-pyran (DCM), DCJTB, quinacridone derivatives such as 2,3-quinacridone, coumarin derivatives such as 3- (2′-benzothiazole) -7-diethylaminocoumarin, and condensed polycyclic aromatics such as perylene are used as dopants. And those using 4,4′-bis (2,2-diphenylvinyl) biphenyl as a host and perylene or a distyrylarylene derivative as a dopant.

  The material of the electron injection layer 162 is not particularly limited, and a known material can be used. The electron injection layer 162 is preferably formed of, for example, a material having a low work function. Examples of the material forming the electron injection layer 162 include alkali metals such as lithium and cesium, and alkaline earth metals such as calcium. Examples thereof include fluorides and oxides, magnesium silver, and lithium aluminum alloys.

  The organic EL layer 16 may include, for example, an electron transport layer, a hole injection layer, and a hole transport layer. The materials for the electron transport layer, the hole injection layer, and the hole transport layer are not particularly limited, and known materials can be used. As a material for forming the electron transport layer, for example, 2- (4-biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxadiazole (Bu-PBD), 2,9- Oxides such as dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 1,3-bis (pt-butylphenyl-1,3,4-oxadiazolyl) phenyl (OXD-7) Examples thereof include diazole derivatives, triazole derivatives, quinolinol metal complexes, and triphenyldiamine derivatives. Examples of the material of the hole injection layer include arylamine derivatives such as copper phthalocyanine (Cu—Pc), m-MTDATA, 2-TNATA, and starburst aromatic amines such as TCTA, spiro-TAD, 2, 3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN), hole-injecting organic materials such as vanadium pentoxide and molybdenum trioxide And the like chemically doped. Examples of the material for the hole transport layer include bis (di (p-tolyl) aminophenyl) -1,1-cyclohexane, N, N′-diphenyl-NN—bis (1-naphthyl) -1,1. Trivalent diamines such as' -biphenyl) -4,4'-diamine (α-NPD), 4,4'-bis (m-tolylphenylamino) biphenyl (TPD), TAPC, and triphenylamine are further increased. TPTR, TPTE, NTPA, starburst aromatic amine and the like. In the organic EL layer 16, the stacking positions of the electron injection layer, the electron transport layer, the hole injection layer, and the hole transport layer can be appropriately set based on the polarity of the organic EL element 1, for example.

  In the organic EL element 1, examples of the material for forming the substrate 10 include a transparent substrate such as glass or a flexible film.

  The magnitude | size in particular of the organic EL element 1 is not restrict | limited, For example, the magnitude | size of the light emission unit in the organic EL element 1 is 0.05-1000 mm, 0.05-500 mm, 0.05-300 mm. The light emission unit represents, for example, one light emitting element and means the minimum unit that functions as a light source. The size of the light emitting unit is, for example, one side and the diameter of the light emitting unit. As will be described later, the organic EL element 1 can be reduced in size, for example, so that the size of the light emitting unit can be set to 0.5 mm or less, for example.

  The gate electrode 11, the gate insulating film 12, the source electrode 14, and the drain electrode 15 function as a current control unit that controls a current flowing through the organic EL layer 16. As described above, the organic EL element 1 has terminals in the element that control current and serve as current inlet and outlet.

  The organic EL element 1 includes a pnp transistor and a pn organic EL layer when viewed from the hole injection side with respect to the organic EL layer 16. That is, the organic EL element 1 is an element that controls and drives the pn diode of the organic EL layer 16 by the pnp transistor portion when viewed from the hole injection side to the organic EL layer 16. In the following description, the organic EL layer 16 may be referred to as a pn diode, and the semiconductor layer 13 may be referred to as a pnp transistor portion. When viewed from the electron injection side with respect to the organic EL layer 16, the organic EL element 1 includes an np organic EL and a pnp transistor unit.

  When a negative potential is applied to the gate, a p-type inversion layer (p-channel) is formed on the gate insulating film 12 of the n-type semiconductor layer 131, and the source electrode 14 and the p-type semiconductor layer 132 are opened. The organic EL layer 16 is a light emitting diode, and the source electrode 14 and the drain electrode 15 are brought into conduction (ON) through the diode. For this reason, the source electrode 14 and the drain electrode 15 can also be referred to as an anode and a cathode, respectively. By turning off the gate voltage, there is no channel and the device is in a non-conductive (OFF) state.

  In the ON state, the pnp transistor portion in the organic EL element 1 is injected with holes from the p-channel in the source electrode 14 and the n-type semiconductor layer 131 toward the p-type semiconductor layer 132 and simultaneously toward the light-emitting layer 161. Electrons are injected from the drain electrode 15 and the electron injection layer 162, and these are recombined in the light emitting layer 161 to emit light.

  The p-type semiconductor layer 132 transports holes injected from the source electrode 14. For this reason, the p-type semiconductor layer 132 can also function as a hole transport layer and a hole injection layer of the organic EL layer 16, for example.

  Thus, in the organic EL element, by including the current control means, the current flowing through the organic EL layer 16 can be controlled, and the light emission of the light emitting layer 16 can be controlled.

  Since the source electrode 14 and the drain electrode 15 are arranged so as to sandwich the organic EL layer 16 and the semiconductor layer 13, the surface area of the source electrode 14 and the drain electrode 15 is large, and electrons and holes (carriers) are formed in a wide region of the element. ) Can be applied, the current density per element can be increased. In addition, a substantially constant voltage drop occurs between the source electrode 14 and the drain electrode 15, and the degree of the voltage drop is small. For this reason, the organic EL element 1 is larger than the general bipolar (bipolar) organic light-emitting transistor and the organic light-emitting transistor having a lateral MOSFET structure in which the source electrode and the drain electrode are arranged in the same layer. As the current becomes higher, the power loss can be reduced.

  Further, in the conventional lateral MOSFET structure, pinch-off occurs, which affects the light emission. On the other hand, the organic EL element 1 of the present invention can suppress the pinch-off and reduce the influence on the light emission.

  Further, in the organic EL element 1, when electrons are injected from the drain electrode 15, the conductivity of the light emitting layer 161 including the organic semiconductor is modulated, and the resistance is reduced. For this reason, the organic EL element 1 can inject both holes and electrons into the light emitting layer 161 at a high density, and can flow a large current. On the other hand, in the organic light-emitting transistor having the conventional MOSFET structure, the carrier is unipolar and the current cannot be increased. Thus, since the organic EL element 1 can flow a large current with a low resistance (low ON resistance) as compared with the conventional organic light emitting transistor, there is little deterioration / breakdown due to heat, withstand voltage, short circuit. Resistance can be increased. Moreover, since the organic EL element 1 can flow a large current with a low resistance, it can obtain a high luminance and a high luminous flux as compared with a conventional organic light emitting transistor.

  As described above, the organic EL element 1 can obtain a high luminance and a high luminous flux as compared with the conventional organic light emitting transistor. For example, it is not necessary to increase the area in order to increase the luminance, and the size is reduced. Is possible.

  In addition, since the conventional vertical organic light-emitting transistor has a low insulation resistance, the characteristic change due to punch-through or heat is large, whereas the organic EL element 1 of the present invention has a four-layer structure. Can be suppressed.

  Furthermore, the organic EL element 1 can be expected to operate at a higher speed in response speed and ON / OFF speed than a general organic light emitting transistor. In a general organic light emitting transistor, accumulated charges of carriers are generated, and therefore a delay in ON / OFF time is likely to occur. On the other hand, the organic EL element 1 has a pnpn four-layer structure from the source electrode 14 (anode) to the drain electrode 15 (cathode), and includes one pnp transistor and one npn transistor. become. Thereby, since the accumulated charge can be reduced, the organic EL element 1 can further increase the operation speed. Therefore, the organic EL element 1 of the present invention is suitable when a high response speed is required, such as optical communication.

(Modification)
The n-type semiconductor layer 131 in the organic EL element 1 may be formed of an organic semiconductor. In this case, the layer denoted by reference numeral 133 in FIG. 1 is a p-type organic semiconductor layer (third semiconductor layer) that is included in the n-type semiconductor layer 131 and is formed of a material different from that of the n-type semiconductor layer 131. Layer). Except for this point, the present modification is the same as the first embodiment, and the description of the first embodiment can be used for the description of the present modification.

  In the case where the n-type semiconductor layer 131 is formed of an organic semiconductor, the carriers flowing through the channel are polar carriers injected from the electrodes. That is, for example, when a channel is formed in a p-type semiconductor, it becomes a p-channel transistor that controls the hole current.

  Examples of the organic material for forming the p-type semiconductor layer include the materials described above.

When the n-type semiconductor layer 131 is formed of an organic semiconductor, the organic EL element 1 may further include a charge generation layer in contact with the n-type semiconductor layer 131. Examples of the material for forming the charge generation layer include phthalocyanine, molybdenum oxide (MoO ₃ ), and vanadium oxide (V ₂ O ₅ ).

  Also in this modification, the polarity of the organic EL element 1 may be reversed as described above. In this case, the layer denoted by reference numeral 131 in FIG. 1 is a p-type organic semiconductor layer, and the layer denoted by reference numeral 133 in FIG. 1 is an n-type organic semiconductor layer. Examples of the organic material for forming the n-type semiconductor layer include the materials described above.

(Embodiment 2)
FIG. 2 is a cross-sectional view (schematic diagram) of the organic EL element in the present embodiment. As shown in FIG. 2, the organic EL element 1 of the present embodiment includes a source electrode 14 stacked on a substrate 10, and a gate electrode 11 formed on the gate electrode 11 via a gate insulating film 12. The electrode 11 has a horizontal structure extending in the planar direction. The n-type semiconductor layer 131 is formed so as to cover the source electrode 14 along the p-type inversion layer 133 formed on the gate insulating film of the n-type semiconductor layer 131. Except for the above points, the second embodiment is the same as the first embodiment. By forming the organic EL element 1 in this way, the same effects as those of the first embodiment can be obtained.

  In the organic EL element 1 of the present embodiment, since the surface area of the source electrode 14 and the drain electrode 15 is large, for example, carriers can flow in a wide area of the element. For this reason, for example, the current density per element can be increased. Further, since the area of the region where the source electrode 14 and the drain electrode 15 are opposed is large, for example, a uniform electric field can be applied in a wide region. Thus, since the organic EL element 1 of this embodiment can obtain a larger and more stable current and a larger light emission area, it can obtain light emission with high efficiency and high luminance. Further, power loss can be further reduced.

(Embodiment 3)
FIG. 3 is a cross-sectional view (schematic diagram) and a plan view of the organic EL element in the present embodiment. As shown in FIG. 3A, in the organic EL element 1 of the present embodiment, a source electrode 14, a semiconductor layer 13, and an organic EL layer 16 are stacked in the above order on a substrate 10. The gate electrode 11 is formed on the substrate 10 so as to be in contact with the source electrode 14 and the n-type semiconductor layer 131 and the p-type semiconductor layer 132 with the gate insulating film 12 interposed therebetween. It has a vertical structure extending vertically. Except for the above points, the second embodiment is the same as the first embodiment.

  As described above, in the organic EL element 1 of the present embodiment, the gate electrode 11 can be provided on the substrate 10 by providing the gate electrode 11 in a vertical configuration. For this reason, the number of light emitting units per unit area can be increased, and higher brightness and higher luminous flux can be obtained.

  As shown in FIG. 3B, the gate electrode 11 preferably has a round shape when viewed from above. With such a configuration, more gate electrodes 11 can be provided on the substrate 10.

(Embodiment 4)
FIG. 4 is a plan view of the organic EL element in the present embodiment. As shown in FIG. 4, the organic EL element 1 of the present embodiment is a single unit in which three gate electrodes 11 are formed on one substrate 10. The light emitting layer 16 emits RGB (red, green, blue) colors corresponding to the three gate electrodes 11. Except for the above points, the present embodiment is the same as the above embodiment. In FIG. 4, the gate electrode 11 has the vertical configuration, but the organic EL element 1 of the present embodiment is not limited to this, and the gate electrode 11 may have the horizontal configuration.

  The method for causing each light emitting layer 16 to correspond to each color is not particularly limited. For example, the light emitting layer 16 can be separately applied by a known method. For example, RGB three color light emitting layers are separately formed using a stencil mask. A method in which the organic EL light emitting layer is white and a color filter is used to separate the light into three colors using a color filter, and the organic EL light emitting layer is blue and a color conversion layer (CCM) is used on the light extracting surface side. For example, a method of converting from blue to green and blue to red and dividing the color into three colors can be given.

  The color corresponding to each light emitting layer 16 is not particularly limited. For example, RGBW (red, green, blue, white), BY (blue, yellow), W (white) in addition to RGB (red, green, blue). Is given.

  The number of the organic EL elements 1 included in one unit is not particularly limited, and is, for example, 3-6, 2-4, or 1.

  With the organic EL element 1 having such a configuration, the current obtained from the organic EL element 1 can be adjusted by adjusting the current with the gate potential corresponding to each color.

(Embodiment 5)
The organic EL light source of the present invention includes an organic EL element 1. The organic EL light source of the present invention can be configured, for example, by arranging a plurality of organic EL elements (light emitting units) on a transparent substrate. Since the organic EL element 1 can flow a large current, for example, a high-luminance organic EL light source can be obtained.

  FIG. 5 is a diagram showing an equivalent circuit of the organic EL light source of the present embodiment. In FIG. 5, an organic EL light source of 2 × 2 units is shown as an example. As shown in FIG. 5, source lines (S (A)) and drain lines (D (K)) are alternately arranged. Further, the source line and the drain line are arranged so as to intersect the gate line. Here, the source line is a signal / power supply line, and the gate line is an address line. Each organic EL element is connected to a source line, a drain line, and a gate line. The gate line is connected to the address selection circuit, and the source line is connected to the data selection circuit / power supply scanning circuit. By the selection circuit, an element can be selected to emit light.

(Embodiment 6)
The organic EL lighting device of the present invention includes the organic EL light source of the present invention. Since the organic EL element 1 can flow a large current, the organic EL element 1 can also be suitably used for an organic EL lighting device that requires high luminance. Further, the organic EL element 1 can be reduced in size, so that the number of light emitting units per unit area can be increased. According to such a configuration, since the voltage drop is small as compared with the conventional technique in which the area of the light emitting unit is increased, the luminance of the light emitting unit per unit area becomes uniform, and the luminance unevenness of the organic EL lighting device is suppressed. be able to.

(Embodiment 7)
The organic EL communication device of the present invention includes the organic EL light source of the present invention. Since the organic EL element 1 can flow a large current, it can also be suitably used for an organic EL communication apparatus that requires high luminance. When the organic EL light source of the present invention is used as an organic EL communication device, for example, it can be used as a data signal by combining ON / OFF of light and a two-dimensional video signal. be able to.

  The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  The organic EL device of the present invention has higher voltage tolerance and can pass a large current. For this reason, for example, the organic EL element of this invention can be used conveniently for an organic EL display apparatus, a communication apparatus, illumination, etc.

  A part or all of the above embodiment can be described as in the following supplementary notes, but is not limited to the following.

(Appendix 1)
A substrate, an organic EL layer, a semiconductor layer in contact with the lower surface side of the organic EL layer, and current control means for controlling a current flowing through the organic EL layer,
The organic EL layer includes a light emitting layer,
The light emitting layer includes an organic semiconductor,
The semiconductor layer includes a first semiconductor layer and a second semiconductor layer,
The current control means includes a gate electrode, a gate insulating film, a source electrode, and a drain electrode,
One of the first semiconductor layer and the second semiconductor layer is an n-type semiconductor layer, and the other is a p-type semiconductor layer,
The source electrode is in contact with the lower surface side of the semiconductor layer, the drain electrode is in contact with the upper surface side of the organic EL layer,
The first semiconductor layer is formed so as to cover the source electrode;
The gate electrode is in contact with the source electrode and the first semiconductor layer through the gate insulating film;
When the first semiconductor layer is a semiconductor layer containing an inorganic semiconductor, an inversion layer is formed in the first semiconductor layer by application to the gate electrode,
When the first semiconductor layer is a semiconductor layer including an organic semiconductor, the first semiconductor layer includes a third semiconductor layer, and the third semiconductor layer is a type of the first semiconductor layer. An organic EL element characterized by being a semiconductor layer of a different type.

(Appendix 2)
An organic EL light source comprising the organic EL element according to appendix 1.

(Appendix 3)
An organic EL lighting device comprising the organic EL light source according to appendix 2.

(Appendix 4)
An organic EL communication device comprising the organic EL light source according to appendix 2.

DESCRIPTION OF SYMBOLS 1 Organic EL element 10 Substrate 11 Gate electrode 12 Gate insulating film 13 Semiconductor layer 131 N-type semiconductor layer (first semiconductor layer)
132 p-type semiconductor layer (second semiconductor layer)
133 Inversion layer (third semiconductor layer)
14 Source electrode 15 Drain electrode 16 Organic EL layer 161 Light emitting layer 162 Electron injection layer

Claims (10)

A substrate, an organic EL layer, a semiconductor layer in contact with the lower surface side of the organic EL layer, and current control means for controlling a current flowing through the organic EL layer,
The organic EL layer includes a light emitting layer,
The light emitting layer includes an organic semiconductor,
The semiconductor layer includes a first semiconductor layer and a second semiconductor layer,
The current control means includes a gate electrode, a gate insulating film, a source electrode, and a drain electrode,
One of the first semiconductor layer and the second semiconductor layer is an n-type semiconductor layer, and the other is a p-type semiconductor layer,
The source electrode is in contact with the lower surface side of the semiconductor layer, the drain electrode is in contact with the upper surface side of the organic EL layer,
The first semiconductor layer is formed so as to cover the source electrode;
The gate electrode is in contact with the source electrode and the first semiconductor layer through the gate insulating film;
When the first semiconductor layer is a semiconductor layer containing an inorganic semiconductor, an inversion layer is formed in the first semiconductor layer by application to the gate electrode,
When the first semiconductor layer is a semiconductor layer including an organic semiconductor, the first semiconductor layer includes a third semiconductor layer, and the third semiconductor layer is a type of the first semiconductor layer. An organic EL element characterized by being a semiconductor layer of a different type. The organic EL element according to claim 1, wherein the gate electrode is further in contact with the second semiconductor layer through the gate insulating film. The organic EL element according to claim 1, wherein the gate electrode, the gate insulating film, the semiconductor layer, and the organic EL layer are laminated in the order on the substrate. 4. The organic EL element according to claim 1, wherein at least one selected from the group consisting of the gate electrode, the source electrode, and the drain electrode is a transparent electrode. 5. The organic EL element according to claim 1, wherein the organic EL layer further includes an electron injection layer. The organic EL element according to claim 1, wherein the gate electrode has a structure extending in a planar direction. The organic EL element according to any one of claims 1 to 6, wherein the gate electrode has a structure extending perpendicularly to a planar direction. The organic EL element according to claim 1, wherein the gate electrode has a round shape when viewed from above. The current control means includes a plurality of the gate electrodes,
The organic EL element according to claim 1, wherein the light emitting layer emits a plurality of colors corresponding to the plurality of gate electrodes. An organic EL light source comprising the organic EL element according to claim 1.

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