JP2019083187A - Organic electroluminescent element, organic electroluminescent device, and electronic device - Google Patents

Abstract

To provide an organic electroluminescent element, an organic electroluminescent device, and an electronic device capable of improving the device characteristics without impairing the current stability.SOLUTION: An organic electroluminescent element according to an embodiment includes a first reflective layer, a second reflective layer, and a monochromatic light emitting organic light emitting layer provided between the first reflective layer and the second reflective layer. The organic electroluminescent element further includes an Ag electrode layer provided between the organic light emitting layer and the second reflective layer, and a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an organic electroluminescent device, an organic electroluminescent device, and an electronic device.

  Various organic electroluminescent devices (organic electroluminescent displays) using organic electroluminescent elements have been proposed (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2007-533157

  By the way, in the organic electroluminescent device, it is required to improve the device characteristics without impairing the current supply stability of the organic electroluminescent device. Therefore, it is desirable to provide an organic electroluminescent device, an organic electroluminescent device, and an electronic device capable of improving the device characteristics without impairing the conduction stability.

  A first organic electroluminescent device according to an embodiment of the present disclosure includes a first reflective layer, a second reflective layer, and an organic light emitting organic provided between the first reflective layer and the second reflective layer. And a light emitting layer. The organic electroluminescent device further includes an Ag electrode layer provided between the organic light emitting layer and the second reflective layer, and a Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.

  A second organic electroluminescent device according to an embodiment of the present disclosure includes a first reflective layer, a second reflective layer, and an organic light emitting organic provided between the first reflective layer and the second reflective layer. And a light emitting layer. The organic electroluminescent device further includes an electrode layer thinner than the second reflective layer, provided between the organic light emitting layer and the second reflective layer, and between the electrode layer and the second reflective layer. A film thickness adjusting layer having a resistance higher than that of the electrode layer, and a wiring layer for supplying a current between the first reflective layer and the electrode layer are provided.

  An organic electroluminescent device according to an embodiment of the present disclosure includes a plurality of organic electroluminescent devices. In this organic electroluminescent device, at least one of the plurality of organic electroluminescent devices has the same component as the above first or second organic electroluminescent device.

  An electronic device according to an embodiment of the present disclosure includes an organic electroluminescent device. The organic electroluminescent device in this electronic device has the same components as the above first or second organic electroluminescent device.

  According to a first organic electroluminescent device according to an embodiment of the present disclosure, and an organic electroluminescent device and an electronic device provided with the first organic electroluminescent device, the first reflective layer and the second reflective layer Between the layers, the Yb electron injection layer and the Ag electrode layer, which are in contact with each other, are stacked in this order from the organic light emitting layer side, so that the device characteristics can be improved without impairing the current supply stability. The above content is an example of the present disclosure. The effects of the present disclosure are not limited to those described above, and may be other different effects or may include other effects.

  According to a second organic electroluminescent device according to an embodiment of the present disclosure, and an organic electroluminescent device and an electronic device provided with the second organic electroluminescent device, the first reflective layer and the second reflective layer Between the organic light emitting layer and the second reflective layer, and a film thickness adjusting layer having a resistance higher than that of the electrode layer; Since the wiring layer for supplying a current is provided between the electrode layer and the electrode layer, the device characteristics can be improved without impairing the current supply stability. The above content is an example of the present disclosure. The effects of the present disclosure are not limited to those described above, and may be other different effects or may include other effects.

It is a figure showing an example of the section composition of the organic electroluminescence element concerning a 1st embodiment of this indication. It is a figure showing an example of an electric current and a path of light. It is a figure showing an example of the relation between Ag film thickness and sheet resistance. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a comparative example. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a modification. It is a figure showing an example of the relationship between Ag film thickness, sheet resistance, Yb electron injection layer, and Yb protective layer. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a modification. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a modification. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a modification. It is a figure showing an example of the cross-sectional structure of the organic electroluminescent element which concerns on a modification. It is a figure showing an example of a schematic structure of the organic electroluminescence device concerning a 2nd embodiment of this indication. It is a figure showing an example of a circuit structure of the pixel of FIG. It is a top view showing an example of schematic structure of the display panel of FIG. It is a figure which represents an example of the appearance of the electronic equipment provided with the organic electroluminescence device of this indication perspectively. It is a figure which represents an example of the appearance of the lighting installation provided with the organic electroluminescent element of this indication perspectively.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferable specific example of the present disclosure. Accordingly, the numerical values, shapes, materials, components, arrangement positions and connection forms of the components, and the like described in the following embodiments are merely examples, and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in the independent claims indicating the highest concept of the present disclosure are described as optional components. Each drawing is a schematic view and is not necessarily strictly illustrated. Further, in the drawings, substantially the same configurations are given the same reference numerals, and overlapping descriptions will be omitted or simplified. The description will be made in the following order.

1. First embodiment (organic electroluminescent device)
2. Modification of First Embodiment (Organic Electroluminescent Device)
3. Second embodiment (organic electroluminescent device)
4. Application example (Electronic equipment, lighting equipment)

<1. First embodiment>
[Constitution]
FIG. 1 illustrates an example of a cross-sectional configuration of an organic electroluminescent device 1 according to a first embodiment of the present disclosure. The organic electroluminescent element 1 is provided, for example, on a substrate 10. The organic electroluminescent element 1 includes, for example, a reflective layer 11 (anode, first reflective layer), a hole injection layer 12, a hole transport layer 13, an organic light emitting layer 14, an electron transport layer 15, an electron injection layer 16 (Yb electrons) The element structure is configured to include the injection layer), the cathode 17 (Ag electrode layer), the film thickness adjustment layer 18 and the reflective layer 19 (second reflective layer) in this order from the substrate 10 side. The hole injection layer 12 and the hole transport layer 13 are provided on the hole injection side of the organic light emitting layer 14. The electron transport layer 15 and the electron injection layer 16 are provided on the electron injection side of the organic light emitting layer 14. The organic light emitting layer 14 is an organic light emitting layer of single color light emission provided between the reflective layer 11 and the reflective layer 19. The cathode 17 is an electrode layer provided between the organic light emitting layer 14 and the reflective layer 19. The electron injection layer 16 is in contact with the side of the organic light emitting layer 14 of the cathode 17. The film thickness adjustment layer 18 is provided between the cathode 17 and the reflective layer 19.

  In the present embodiment, the organic electroluminescent element 1 is provided with a microcavity structure. The microcavity structure has, for example, an effect of enhancing light of a specific wavelength by utilizing resonance of light generated between the reflective layer 11 and the reflective layer 19. The light emitted from the organic light emitting layer 14 is multiply reflected between the reflective layer 11 and the reflective layer 19. At this time, a specific wavelength component of the light emitted from the organic light emitting layer 14 is intensified. The optical path length between the reflective layer 11 and the reflective layer 19 corresponds to the emission spectrum peak wavelength of the light emitted from the organic light emitting layer 14. Due to the microcavity structure, light emitted from the organic light emitting layer 14 is repeatedly reflected within a predetermined optical length range between the reflecting layer 11 and the reflecting layer 19 as shown in FIG. Light L of a specific wavelength corresponding to the length is resonated and enhanced, while light of a wavelength not corresponding to the optical path length is weakened. As a result, the spectrum of the light L extracted to the outside is sharp and has high intensity, and the luminance and color purity are improved. Therefore, the distance between the reflective layer 11 and the reflective layer 19 is the optical path length in which the cavity is generated. In the microcavity structure, as the film thickness increases, first order interference (first cavity), second order interference (second cavity), third order interference (third cavity) and the like occur.

  The substrate 10 is, for example, a light transmitting substrate having light transparency such as a transparent substrate, and is, for example, a glass substrate. Examples of the material of the glass substrate used for the substrate 10 include non-alkali glass, soda glass, non-fluorescent glass, phosphoric acid glass, boric acid glass, quartz and the like. The substrate 10 is not limited to the glass substrate, and may be a translucent resin substrate or a TFT (thin film transistor) substrate which is a backplane of the organic EL display device. Examples of the material of the translucent resin substrate used for the substrate 10 include acrylic resins, styrene resins, polycarbonate resins, epoxy resins, polyethylene, polyester, and silicone resins. The substrate 10 may be a substrate with high flexibility or a highly rigid substrate with little flexibility.

  The reflective layer 11 is formed, for example, on the substrate 10. The reflective layer 11 is a reflective electrode (reflective metal layer) having reflectivity. As a material of a reflective electrode, aluminum (Al), silver (Ag), or an alloy of aluminum or silver etc. are mentioned, for example. The reflective layer 11 is used as an anode. The reflective layer 11 may be an Ag electrode layer made of Ag or an Ag alloy having high reflectance.

  The hole injection layer 12 has a function of injecting holes injected from the reflective layer 11 (anode) into the hole transport layer 13 and the organic light emitting layer 14. The hole injection layer 12 is made of, for example, an inorganic material having a hole injection property. As an inorganic material having a hole injection property, for example, oxidation of silver (Ag), molybdenum (Mo), chromium (Cr), vanadium (V), tungsten (W), nickel (Ni), iridium (Ir), etc. Substances (inorganic oxides) and the like can be mentioned. The hole injection layer 12 is made of, for example, a vapor deposited film or a sputtered film of an inorganic oxide. The hole injection layer 12 may be made of an organic material having a hole injection property. Examples of the organic material having a hole injection property include conductive polymer materials such as PEDOT (a mixture of polythiophene and polystyrene sulfonic acid). The hole injection layer 12 is made of, for example, a coating film of an organic material. The hole injection layer 12 may be formed of a vapor deposition film of an organic material.

  The hole transport layer 13 has a function of transporting the holes injected from the reflective layer 11 to the organic light emitting layer 14. The hole transport layer 13 is made of, for example, a material (hole transport material) having a function of transporting holes injected from the reflective layer 11 to the organic light emitting layer 14. Examples of the hole transporting material include arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, Styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, butadiene compounds, polystyrene derivatives, hydrazone derivatives, triphenylmethane derivatives, tetraphenyl benzine derivatives, etc., or materials composed of a combination thereof can be mentioned.

  The organic light emitting layer 14 has a function of emitting light of a predetermined color (monochromatic light) by recombination of holes and electrons. The organic light emitting layer 14 is configured to include an organic light emitting material that emits light by generating excitons by recombination of holes and electrons. The organic light emitting layer 14 is, for example, a coating film, and is formed, for example, by applying and drying a solution containing the above-described organic light emitting material as a main component of a solute. The organic light emitting layer 14 may be formed of a vapor deposition film.

  The organic light emitting layer 14 is constituted of, for example, a single layer organic light emitting layer or a plurality of stacked organic light emitting layers. In the case where the organic light emitting layer 14 is formed of a plurality of stacked organic light emitting layers, the organic light emitting layer 14 is, for example, a stack of a plurality of organic light emitting layers in which the main components of the organic light emitting materials described above are mutually common. It is a thing.

  The organic light emitting material which is a raw material (material) of the organic light emitting layer 14 is, for example, a material in which a host material and a dopant material are combined. The organic light emitting material which is a raw material (material) of the organic light emitting layer 14 may be a dopant material alone. The host material is mainly responsible for charge transport of electrons or holes, and the dopant material is responsible for light emission. The host material and the dopant material are not limited to only one type, and may be a combination of two or more types.

  As a host material of the organic light emitting layer 14, for example, an amine compound, a fused polycyclic aromatic compound, or a heterocyclic compound is used. As an amine compound, a monoamine derivative, a diamine derivative, a triamine derivative, a tetraamine derivative is used, for example. Examples of the fused polycyclic aromatic compound include anthracene derivatives, naphthalene derivatives, naphthacene derivatives, phenanthrene derivatives, chrysene derivatives, fluoranthene derivatives, triphenylene derivatives, pentacene derivatives, and perylene derivatives. As a heterocyclic compound, for example, carbazole derivative, furan derivative, pyridine derivative, pyrimidine derivative, triazine derivative, imidazole derivative, pyrazole derivative, triazole derivative, oxazole derivative, oxadiazole derivative, pyrrole derivative, indole derivative, azaindole derivative, Examples include azacarbazole, pyrazoline derivatives, pyrazolone derivatives, and phthalocyanine derivatives.

  Moreover, as a dopant material of the organic light emitting layer 14, for example, pyrene derivative, fluoranthene derivative, arylacetylene derivative, fluorene derivative, perylene derivative, oxadiazole derivative, anthracene derivative, or chrysene derivative is used. Moreover, as a fluorescent dopant material of the organic light emitting layer 14, a metal complex may be used. As the metal complex, for example, those having a metal atom such as iridium (Ir), platinum (Pt), osmium (Os), gold (Au), rhenium (Re) or ruthenium (Ru) and a ligand Can be mentioned.

  The electron transport layer 15 has a function of transporting the electrons injected from the cathode 17 to the organic light emitting layer 14. The electron transport layer 15 includes, for example, a material (electron transport material) having a function of transporting electrons injected from the cathode 17 to the organic light emitting layer 14. The electron transport layer 15 is made of, for example, a vapor deposition film or a sputter film. The above-mentioned electron transporting material is, for example, an aromatic heterocyclic compound containing one or more hetero atoms in the molecule. As an aromatic heterocyclic compound, the compound which contains a pyridine ring, a pyrimidine ring, a triazine ring, a benzimidazole ring, a phenanthroline ring, a quinazoline ring etc. in frame | skeleton is mentioned, for example. The above-mentioned electron transporting material may be doped with a metal having an electron transporting property. In this case, the electron transport layer 15 is an organic electron transport layer containing a doped metal. By the metal which has electron transportability being contained in the electron transport layer 15, the electron transportability of the electron transport layer 15 can be improved. Examples of the doping metal contained in the electron transporting layer 15 include transition metals such as ytterbium (Yb).

  The electron injection layer 16 has a function of injecting electrons injected from the cathode 17 into the electron transport layer 15 and the organic light emitting layer 14. The electron injection layer 16 is made of, for example, a material (electron injection material) having a function of promoting injection of electrons from the cathode 17 to the electron transport layer 15 and the organic light emitting layer 14. Examples of the electron injecting material include ytterbium (Yb). The electron injection layer 16 may be, for example, a Yb layer composed of Yb. The doped metal contained in the electron transport layer 15 may be the same metal as the electron injecting material described above. The film thickness of the electron injection layer 16 is, for example, 0.1 nm or more and 5 nm or less. In the electron injection layer 16, when the thickness is too thin, the function of promoting electron injection is reduced, and when the thickness is too thick, the light emission characteristics may be reduced due to the decrease in transmittance. Further, the Yb layer has a function of improving the film quality of the cathode 17 (Ag) formed in contact with the side of the cathode 17 and reducing the sheet resistance. As a result, the device characteristics can be improved without losing the current supply stability even in the thin film thickness cathode 17 (Ag).

  The cathode 17 is a light transmitting transparent electrode (light transmitting metal layer). As a material of a transparent electrode, aluminum (Al), magnesium (Mg), silver (Ag), an aluminum lithium alloy, a magnesium silver alloy etc. are used, for example. The cathode 17 which functions as a transparent electrode is, for example, an Al layer, an Mg layer, an Ag layer, an AlLi alloy layer or an MgAg alloy layer having a thickness of 0.1 nm to 10 nm. In the present embodiment, in the case where the substrate 10 and the reflective layer 11 have reflectivity and the cathode 17 and the reflective layer 19 have translucency, the organic electroluminescent element 1 is disposed from the side of the reflective layer 19. It has a top emission structure that emits light.

  When the film thickness of the cathode 17 is increased, the cavity effect due to the reflection of the cathode 17 is intensified, the front luminance is high, and the viewing angle characteristics are degraded. When the film thickness of the cathode 17 is reduced, the cavity effect by the cathode 17 is reduced, the front luminance is suppressed, and the viewing angle characteristics are improved. Since the cavity effect also occurs in the reflective layer 19, the cavity effect is complicated when the film thickness of the cathode 17 is increased to increase the reflectivity. The change of the light emission characteristic with respect to the film thickness deviation of the finish for the design of the film configuration also becomes large. In addition, as the change in light emission characteristics increases, the risk of uneven light emission also increases.

  Therefore, in the present embodiment, for example, the film thickness of the cathode 17 is thinner than that of the reflective film 19. For example, the film thickness of the reflective film 19 is desirably 5 nm or more and 30 nm or less, and the film thickness of the cathode 17 is thinner than the film thickness of the reflective film 19 and 0.1 nm or more and 10 nm or less Is desirable. Further, the film thickness of the cathode 17 is thinner than the film thickness of the reflective film 19, and it is more preferable that the film thickness be 0.1 nm or more and 5 nm or less. By doing so, the reflection by the cathode 17 is suppressed, the cathode 17 hardly functions as a reflection layer of the cavity, and the deterioration of the viewing angle characteristics and the deterioration of the device characteristics due to the film thickness deviation can be suppressed.

  On the other hand, if the thickness of the cathode 17 is reduced, the sheet deterioration is aggravated. In other words, it is necessary to make the cathode 17 as thin as possible and to suppress the increase in sheet resistance. Therefore, in the present embodiment, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. By forming the cathode 17 on the electron injection layer 16 made of Yb, the sheet resistance can be lowered, and the device characteristics can be improved without deteriorating the conduction stability even if the cathode 17 is thin. Can.

  The film thickness adjustment layer 18 is, for example, a layer for adjusting the distance between the reflective layer 11 and the reflective layer 19 to be a predetermined optical path length. The film thickness adjustment layer 18 is made of, for example, a transparent conductive material such as ITO or IZO. The film thickness adjustment layer 18 is, for example, an ITO layer or an IZO layer. The film thickness of the ITO layer or IZO layer used for the film thickness adjustment layer 18 is, for example, a value larger than 40 nm. The film thickness adjustment layer 18 has a higher resistance than the cathode 17 and does not constitute a current path. The film thickness adjusting layer 18 may be a metal non-doped organic layer or a metal doped organic layer. As long as the film thickness adjusting layer 18 does not constitute a current path in the organic electroluminescent element 1, the film thickness adjusting layer 18 can adopt various configurations.

  The reflective layer 19 is a light transmitting transparent electrode (light transmitting metal layer). As a material of a transparent electrode, aluminum (Al), magnesium (Mg), silver (Ag), an aluminum lithium alloy, a magnesium silver alloy etc. are used, for example. The cathode 17 functioning as a transparent electrode is, for example, an Al layer, an Mg layer, an Ag layer, an AlLi alloy layer, or an MgAg alloy layer having a thickness of 5 nm to 30 nm.

  When the organic electroluminescent element 1 is formed as a pixel of a display panel, the organic electroluminescent element 1 includes a plurality of banks 25 for dividing each pixel of the display panel on the substrate 10. The bank 25 is formed of, for example, an insulating organic material. As an insulating organic material, acrylic resin, a polyimide resin, a novolak-type phenol resin etc. are mentioned, for example. The bank 25 is preferably made of, for example, an insulating resin having heat resistance and resistance to a solvent. The bank 25 is formed, for example, by processing an insulating resin into a desired pattern by photolithography and development. The cross-sectional shape of the bank 25 may be, for example, a forward taper type as shown in FIG. 1 or a reverse taper type in which the skirt is narrowed.

  The organic electroluminescent element 1 includes a wire 21 electrically conducted to the reflective layer 11 (anode) and the cathode 17. The wiring 21 is a wiring for supplying a current between the reflective layer 11 (anode) and the cathode 17. 1, a portion of the cathode 17, the electron injection layer 16 and the electron transport layer 15 extending beyond the bank 25 (a portion surrounded by a broken line in FIG. 1. Hereinafter, “wiring layer 21A” and And the electrode layer 21B formed in the peripheral region 20B surrounding the pixel region 20A constitute a part of the wiring 21 for supplying a current between the reflective layer 11 (anode) and the cathode 17. The situation is illustrated. The wiring layer 21A and the electrode layer 21B are provided in the peripheral region (peripheral region 20B) of the pixel region 20A. The electrode layer 21B is provided, for example, in the same layer as the reflective layer 11, and is formed of, for example, the same material as the reflective layer 11. The pixel area 20A includes an area of the organic electroluminescent element 1 facing the area (light emitting area 14A) which emits light by current injection from the reflective layer 11 and the cathode 17. The light emitting region 14 A is generated in the organic light emitting layer 14 by current injection from the reflective layer 11 and the cathode 17. When the reflective layer 11 is surrounded by the bank 25 in the periphery, the light emitting region 14A is substantially the organic light emitting layer 14 in the opening portion formed by the bank 25 and the reflective layer 11 and the hole injection layer 12 occurs in the area opposite to the point where they are in direct contact with each other.

  FIG. 3 shows an example of the relationship between the Ag film thickness and the sheet resistance. In the present embodiment, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. At this time, the thickness of the cathode 17 (Ag layer) is set to 20 nm or less, and the thickness of the electron injection layer 16 (Yb layer) is set to 0.1 nm to 5 nm, as shown in FIG. The sheet resistance value of the electron injection layer 16 (Yb layer) / cathode 17 (Ag layer) is smaller than the sheet resistance value of the Ag single layer. When the thickness of the cathode 17 (Ag layer) is about 5 nm, as shown in FIG. 3, the sheet resistance value of the electron injection layer 16 (Yb layer) / cathode 17 (Ag layer) is 20 ohms. It will be about / sq to 30 ohms / sq. Therefore, the low resistance cathode 17 is realized by setting the thickness of the cathode 17 (Ag layer) to 5 nm or more and 20 nm or less and the thickness of the electron injection layer 16 (Yb layer) to 0.1 nm or more and 5 nm or less. Can. As a result, the device characteristics can be improved without losing the current supply stability even in the thin film thickness cathode 17 (Ag).

  Next, the effects of the organic electroluminescent device 1 according to the present embodiment will be described together with comparative examples. FIG. 4 illustrates an example of the cross-sectional configuration of the organic electroluminescent device 100 according to the comparative example. The organic electroluminescent device 100 corresponds to one in which the cathode 17 is omitted and the film thickness adjustment layer 18 is formed of a metal-doped organic layer in the organic electroluminescent device 1 according to the present embodiment. In the comparative example, the function of the cathode 17 is responsible for the reflective layer 19. In the comparative example, since the reflective layer 19 takes on the function of the cathode 17, the electron injection layer 16 is formed between the film thickness adjustment layer 18 and the reflective layer 19.

  The organic electroluminescent device 100 is provided with a microcavity structure similar to that of the organic electroluminescent device 1 according to the present embodiment. In the present structure, the holes h pass from the reflective layer 11 to the organic light emitting layer 14 through the hole injection layer 12 and the hole transport layer 13. On the other hand, electrons e enter the pixel region 20A from the electrode layer 21 through the electron transport layer 15, the film thickness adjustment layer 18, the electron injection layer 16 and the reflective layer 19 in the peripheral region 20B, and the electron injection layer in the pixel region 20A. 16. Through the film thickness adjustment layer 18 and the electron transport layer 15, go to the organic light emitting layer 14. Then, in the organic light emitting layer 14, the holes h and the electrons e recombine to emit light. When light emission occurs, in the film thickness adjusting layer 18 formed of the metal-doped organic layer, the doped metal is deteriorated with time, and the film thickness adjusting layer 18 has a high resistance. As a result, the voltage applied to the organic electroluminescent device 100 is increased. In addition, the doped metal in the film thickness adjusting layer 18 diffuses to the organic light emitting layer 14 to cause quenching and cause deterioration of the light emitting characteristics. As described above, in the organic electroluminescent device 100, the current supply stability is impaired, and the device characteristics are degraded.

  On the other hand, in the present embodiment, the electron injection layer 16 (Yb electron injection layer) and the cathode 17 (Ag electrode layer) in contact with each other between the reflection layer 11 (anode) and the reflection layer 19 are viewed from the organic light emitting layer 14 side. The laminated body laminated | stacked in this order is provided. In the present structure, the holes h pass from the reflective layer 11 to the organic light emitting layer 14 through the hole injection layer 12 and the hole transport layer 13. On the other hand, electrons e pass from the electrode layer 21 through the electron transport layer 15, the electron injection layer 16 and the cathode 17 into the pixel area 20A in the peripheral area 20B and pass through the electron injection layer 16 and the electron transport layer 15 in the pixel area 20A. Go to the organic light emitting layer 14. Then, in the organic light emitting layer 14, the holes h and the electrons e recombine to emit light. That is, in the present structure, no electricity flows in the film thickness adjusting layer 18. That is, the doped metal is deteriorated with time, and the resistance of the film thickness adjusting layer 18 is not increased. Thereby, the device characteristics can be improved without losing the current supply stability.

  Further, in the present embodiment, the cathode 17 (Ag electrode layer) is thinner than the reflective layer 19. As a result, the cathode 17 and the electron injection layer 16 can be made to hardly function as a reflection layer of the cavity while realizing the low resistance cathode 17. As a result, device characteristics can be improved without impairing the current supply stability.

  Further, in the present embodiment, a film thickness adjustment layer 18 having a resistance higher than that of the cathode 17 (Ag electrode layer) is provided between the cathode 17 (Ag electrode layer) and the reflective layer 19. As a result, the film thickness adjusting layer 18 does not constitute a current path, and therefore, even if the film thickness adjusting layer 18 is a metal-doped organic layer, there is no influence by this. Further, since no current flows in the film thickness adjusting layer 18 in the first place, the metal doped in the film thickness adjusting layer 18 does not diffuse. As a result, device characteristics can be improved without impairing the current supply stability.

<2. Modification of First Embodiment>
[Modification A]
In the above embodiment, for example, as shown in FIG. 5, a protective layer 28 (Yb protective layer) in contact with the reflective layer 19 side of the cathode 17 (Ag electrode layer) may be provided. The protective layer 28 is a layer that functions as a low resistance layer for reducing the resistance value when the cathode 16 (Ag electrode layer) is very thin. The protective layer 28 is, for example, a Yb layer having a thickness of 0.1 nm or more and 5 nm or less. The protective layer 28 has lower resistance than the film thickness adjusting layer 18.

  FIG. 6 shows an example of the relationship between the Ag film thickness and the sheet resistance, the Yb electron injection layer, and the Yb protective layer. In FIG. 6, the cathode 17 is, for example, an Ag layer, and the electron injection layer 16 is, for example, a Yb layer. When the film thickness of the Ag layer is 5 nm and the electron injection layer 16 made of Yb is not provided (comparative example), the sheet resistance value is significantly increased to 10 M ohm / sq or more. I will. On the other hand, in the case where the electron injection layer 16 made of Yb is provided (Example), a sheet resistance value of about 20 ohms / sq to about 30 ohms / sq can realize a low resistance cathode. In addition, when the film thickness of the Ag layer is 2 nm, the electron injection layer 16 made of Yb is not provided (comparative example), or the electron injection layer 16 made of Yb is provided. When the protective layer 28 made of Yb is not provided (Example), the sheet resistance value is greatly increased to 10 M ohm / sq or more. On the other hand, when the electron injection layer 16 of Yb is provided and the protective layer 28 of Yb is provided (Modification A), the sheet resistance is as low as about 350 to 400 ohms / sq. Can be realized. Thus, in this modification, the low resistance cathode 17 can be realized by providing the protective layer 28 (Yb protective layer) in contact with the side of the cathode 17 (Ag electrode layer) on the reflective layer 19 side. . As a result, the device characteristics can be improved without losing the current supply stability even in the thin film thickness cathode 17 (Ag electrode layer).

[Modification B]
In the above embodiment and modification A, for example, as shown in FIGS. 7 and 8, the reflective layer 19 and the cathode 17 (Ag electrode layer) may be electrically conducted. Furthermore, in the above embodiment, the reflective layer 19 may be in contact with, for example, part of the cathode 17 (Ag electrode layer). Specifically, in the above embodiment, the reflective layer 19 and the cathode 17 (Ag electrode layer) are not opposed to the light emitting area 14A of the organic light emitting layer 14 in the thickness direction (for example, the bank 25 and the thickness). Electrical continuity may be established in the opposing regions in the direction or in the peripheral region 20B). As described above, since the reflection layer 19 and the cathode 17 (Ag electrode layer) are electrically conducted, the low resistance reflection layer 19 plays a role of an auxiliary wiring. As a result, the influence of the resistance can be reduced, and a phenomenon (voltage drop) in which a voltage is hardly applied to the central portion of the panel when the panel is enlarged can be reduced. Further, in the configuration in which the film thickness adjustment layer 18 having a resistance higher than that of the cathode 17 (Ag electrode layer) is provided between the cathode 17 (Ag electrode layer) and the reflective layer 19, the film thickness adjustment layer 18 Do not configure the route. Thus, even when the film thickness adjustment layer 18 is a metal-doped organic layer, there is no influence. Further, since no current flows in the film thickness adjusting layer 18 in the first place, the metal doped in the film thickness adjusting layer 18 does not diffuse. As a result, device characteristics can be improved without impairing the current supply stability.

[Modification C]
Further, in the above embodiment, modification A and modification B, when it is possible to control the light emission characteristic change due to the decrease of the transmittance due to the increase of the film thickness of the cathode 17 or the film thickness deviation, the film thickness of the cathode 17 May be equal to or thicker than the film thickness of the reflective film 19. For example, as shown in FIG. 9, the film thickness of the cathode 17 may be equal to or thicker than the film thickness of the reflective film 19. In this case, the sheet resistance of the cathode 17 can be reduced, and the device characteristics can be improved.

[Modification D]
Further, in the above embodiment, modification A and modification B, for example, the thickness of the cathode 17 is relatively thin in the pixel area 20A, and in the area around the pixel area 20B (peripheral area 20B) It may be relatively thick. For example, as shown in FIG. 10, even if the thickness of the cathode 17 is relatively thin in the pixel area 20A and relatively thick in the area around the pixel area 20B (peripheral area 20B) Good. In this case, the voltage drop in peripheral region 20B can be reduced, and device characteristics can be improved.

<3. Second embodiment>
[Constitution]
FIG. 11 illustrates an example of a schematic configuration of the organic electroluminescent device 2 according to the second embodiment of the present disclosure. FIG. 12 illustrates an example of the circuit configuration of each pixel 23 provided in the organic electroluminescent device 2. The organic electroluminescent device 2 includes, for example, a display panel 20, a controller 30, and a driver 40. The display panel 20 has a plurality of pixels 23 arranged in a matrix in the pixel area 20A. The driver 40 is mounted on an outer edge portion of the display panel 20 (a peripheral area 20B which is an area around the pixel area 20A). The controller 30 and the driver 40 drive the display panel 20 based on the video signal Din and the synchronization signal Tin input from the outside.

(Display panel 20)
The display panel 20 displays an image based on the video signal Din input from the outside and the synchronization signal Tin by the active matrix driving of each pixel 23 by the controller 30 and the driver 40. The display panel 20 has a plurality of scan lines WSL extending in the row direction, a plurality of signal lines DTL and a plurality of power supply lines DSL extending in the column direction, and a plurality of pixels 23 arranged in a matrix. doing.

  The scanning line WSL is used to select each pixel 23, and supplies a selection pulse for selecting each pixel 23 for each predetermined unit (for example, pixel row) to each pixel 23. The signal line DTL is used to supply a signal voltage Vsig corresponding to the video signal Din to each pixel 23, and supplies a data pulse including the signal voltage Vsig to each pixel 23. The power supply line DSL supplies power to each pixel 23.

  The plurality of pixels 23 includes, for example, a plurality of pixels 23 that emit red light, a plurality of pixels 23 that emit green light, and a plurality of pixels 23 that emit blue light. The plurality of pixels 23 may be configured to include, for example, a plurality of pixels 23 emitting another color (for example, white, yellow, etc.).

  Each signal line DTL is connected to an output end of a horizontal selector 41 described later. For example, a plurality of signal lines DTL are assigned to each pixel column. Each scanning line WSL is connected to an output end of a light scanner 42 described later. For example, a plurality of scanning lines WSL are allocated to each pixel row. Each power supply line DSL is connected to the output end of the power supply. For example, a plurality of power supply lines DSL are allocated to each pixel row.

  Each pixel 23 has, for example, a pixel circuit 23-1 and an organic electroluminescent element 23-2. The organic electroluminescent device 23-2 is, for example, the organic electroluminescent device 1 according to the above-described embodiment and the modification thereof. At least one of the plurality of pixels 23 included in the display panel 20 includes the organic electroluminescent element 1 according to the above-described embodiment and the modification thereof. That is, at least one of the plurality of organic electroluminescent devices 23-2 included in the display panel 20 is configured of the organic electroluminescent device 1 according to the above-described embodiment and the modification thereof.

  The pixel circuit 23-1 controls light emission / quenching of the organic electroluminescent element 23-2. The pixel circuit 23-1 has a function of holding the voltage written to each pixel 23 by the write scanning described later. The pixel circuit 23-1 includes, for example, a drive transistor Tr1, a write transistor Tr2, and a storage capacitor Cs.

  The write transistor Tr2 controls application of a signal voltage Vsig corresponding to the video signal Din to the gate of the drive transistor Tr1. Specifically, the write transistor Tr2 samples the voltage of the signal line DTL, and writes the voltage obtained by the sampling to the gate of the drive transistor Tr1. The drive transistor Tr1 is connected in series to the organic electroluminescent element 23-2. The drive transistor Tr1 drives the organic electroluminescent element 23-2. The drive transistor Tr1 controls the current flowing to the organic electroluminescent element 23-2 in accordance with the magnitude of the voltage sampled by the write transistor Tr2. The storage capacitor Cs holds a predetermined voltage between the gate and the source of the drive transistor Tr1. The storage capacitor Cs has a role of holding the gate-source voltage Vgs of the drive transistor Tr1 constant during a predetermined period. Note that the pixel circuit 23-1 may have a circuit configuration in which various capacitances and transistors are added to the circuit of 2Tr1C described above, or may have a circuit configuration different from the circuit configuration of 2Tr1C described above. Good.

  Each signal line DTL is connected to the output end of the horizontal selector 41 described later and the source or drain of the write transistor Tr2. Each scanning line WSL is connected to the output terminal of the write scanner 42 described later and the gate of the write transistor Tr2. Each power supply line DSL is connected to the output end of the power supply circuit 33 and the source or drain of the drive transistor Tr1.

  The gate of the write transistor Tr2 is connected to the scan line WSL. The source or drain of the write transistor Tr2 is connected to the signal line DTL. Among the source and drain of the write transistor Tr2, a terminal not connected to the signal line DTL is connected to the gate of the drive transistor Tr1. The source or drain of the drive transistor Tr1 is connected to the power supply line DSL. Among the source and drain of the drive transistor Tr1, a terminal not connected to the power supply line DSL is connected to the anode (the reflective layer 11) of the organic electroluminescent element 23-2. One end of the storage capacitor Cs is connected to the gate of the drive transistor Tr1. The other end of the storage capacitor Cs is connected to a terminal of the source and drain of the drive transistor Tr1 on the side of the organic electroluminescent element 23-2.

(Driver 40)
The driver 40 has, for example, a horizontal selector 41 and a light scanner 42. The horizontal selector 41 applies the analog signal voltage Vsig input from the controller 30 to each signal line DTL, for example, in response to (in synchronization with) the input of the control signal. The light scanner 42 scans the plurality of pixels 23 in predetermined units.

(Controller 30)
Next, the controller 30 will be described. The controller 30 performs, for example, predetermined correction on the digital video signal Din input from the outside, and generates a signal voltage Vsig based on the video signal obtained thereby. The controller 30 outputs, for example, the generated signal voltage Vsig to the horizontal selector 41. The controller 30 outputs a control signal to each circuit in the driver 40, for example, in response to (in synchronization with) a synchronization signal Tin input from the outside.

  Next, the organic electroluminescent device 23-2 will be described with reference to FIG. 13, FIG. 1, and the like. FIG. 13 illustrates a schematic configuration example of the display panel 20.

  The display panel 20 has a plurality of pixels 23 arranged in a matrix. For example, as described above, the plurality of pixels 23 are configured to include the pixels 23 (23R) that emit red light, the pixels 23 (23G) that emit green light, and the pixels 23 (23B) that emit blue light. . In the plurality of pixels 23, for example, the pixel 23R, the pixel 23G, and the pixel 23B constitute a pixel (color pixel 24) in color display.

  The pixel 23R is configured to include an organic electroluminescent element 23-2 that emits red light. The pixel 23G is configured to include an organic electroluminescent element 23-2 that emits green light. The pixel 23B is configured to include an organic electroluminescent element 23-2 that emits blue light. The pixels 23R, 23G, and 23B are, for example, in a stripe arrangement. In each pixel 23, for example, the pixels 23R, 23G, and 23B are arranged in the column direction. Furthermore, in each pixel row, for example, a plurality of pixels 23 emitting light of the same color are arranged in line in the row direction.

  The display panel 20 includes a plurality of banks 25 extending in the row direction (the banks 25 in the first embodiment) and two banks 22 extending in the column direction on the substrate 10. . The plurality of banks 25 and the two banks 22 define the pixel area 20A of the display panel 20. The plurality of banks 25 divides each pixel 23 in each color pixel 24. Two banks 22 define the end of each pixel row. That is, each pixel row is partitioned by two banks 25 and two banks 22.

[effect]
In the present embodiment, at least one of the plurality of organic electroluminescent devices 23-2 included in the display panel 20 is configured of the organic electroluminescent device 1 according to the above-described embodiment and its modification. Therefore, it is possible to realize the organic electroluminescent device 2 which is excellent in light emitting characteristics and has a long life.

<4. Application example>
[Application example 1]
Below, the application example of the organic electroluminescent apparatus 2 demonstrated in the said 2nd Embodiment is demonstrated. The organic electroluminescent device 2 may be a television device, a digital camera, a notebook personal computer, a sheet-like personal computer, a portable terminal device such as a mobile phone or a video camera, or an externally input video signal or internally generated video. The present invention can be applied to display devices of electronic devices in all fields that display signals as images or images.

  FIG. 14 is a perspective view of the appearance of the electronic device 3 according to the application example. The electronic device 3 is, for example, a sheet-like personal computer provided with the display surface 320 on the main surface of the housing 310. The electronic device 3 includes the organic electroluminescent device 2 on the display surface 320 of the electronic device 3. The organic electroluminescent device 2 is disposed such that the display panel 20 faces outward. In this application example, since the organic electroluminescent device 2 is provided on the display surface 320, it is possible to realize the electronic device 3 which is excellent in light emission characteristics and has a long life.

[Application example 2]
Below, the application example of the organic electroluminescent element 1 which concerns on the said embodiment and its modification is demonstrated. The organic electroluminescent device 1 can be applied to a light source of a lighting device in any field, such as a tabletop or floor-standing lighting device or a lighting device for indoor use.

  FIG. 15 illustrates an appearance of a lighting device for a room to which the organic electroluminescent device 1 according to the above-described embodiment and the modification thereof is applied. The illumination device includes, for example, an illumination unit 410 configured to include one or more organic electroluminescent elements 1 according to the above-described embodiment and the modification thereof. The lighting units 410 are disposed on the ceiling 420 of the building at an appropriate number and interval. In addition, according to a use, the illumination part 410 can be installed in arbitrary places, such as not only the ceiling 420 but the wall 430 or a floor (not shown).

  In these illumination devices, illumination is performed by the light from the organic electroluminescent element 1 according to the above-described embodiment and its modification. Thus, a lighting device having excellent light emission characteristics and long life can be realized.

  Although the present disclosure has been described above by citing the embodiment and the application example, the present disclosure is not limited to the embodiment and the like, and various modifications are possible. The effects described in the present specification are merely examples. The effects of the present disclosure are not limited to the effects described herein. The present disclosure may have effects other than those described herein.

Also, for example, the present disclosure can have the following configurations.
(1)
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer;
(2)
The organic electroluminescent device according to (1), further comprising a Yb protective layer in contact with the second reflective layer side of the Ag electrode layer.
(3)
The organic electroluminescent device according to (1) or (2), wherein the Ag electrode layer is thinner than the second reflective layer.
(4)
The organic electroluminescence according to any one of (1) to (3), further including a film thickness adjusting layer having a resistance higher than that of the Ag electrode layer between the Ag electrode layer and the second reflective layer. element.
(5)
(1) to (4), further comprising a wire electrically connected to the first reflective layer and the Ag electrode layer and supplying a current between the first reflective layer and the Ag electrode layer The organic electroluminescent element as described in any one.
(6)
The organic electroluminescent device according to any one of (1) to (5), in which the second reflective layer and the Ag electrode layer are electrically conducted.
(7)
The second reflective layer and the Ag electrode layer are electrically conducted in a region not facing the light emitting region of the organic light emitting layer (8)
The organic electroluminescent device according to any one of (1) to (7), wherein a distance between the first reflective layer and the second reflective layer is an optical path length generated by a cavity.
(9)
Equipped with multiple organic electroluminescent devices,
At least one of the plurality of organic electroluminescent devices is
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer.
(10)
The plurality of organic electroluminescent devices are provided in a pixel area,
The organic electroluminescent device according to (9), wherein the second reflective layer and the Ag electrode layer are electrically conducted in an area around the pixel area.
(11)
An organic electroluminescent device having a plurality of organic electroluminescent devices,
At least one of the plurality of organic electroluminescent devices is
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer;
(12)
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An electrode layer provided between the organic light emitting layer and the second reflective layer, the electrode layer being thinner than the second reflective layer;
A film thickness adjustment layer provided between the electrode layer and the second reflective layer, having a higher resistance than the electrode layer;
An organic electroluminescent device comprising: a wiring layer for supplying a current between the first reflective layer and the electrode layer.
(13)
The organic electroluminescent element according to (12), wherein the second reflective layer and the electrode layer are electrically conducted in an area around the pixel area.
(14)
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An electrode layer provided between the organic light emitting layer and the second reflective layer;
A film thickness adjustment layer provided between the electrode layer and the second reflective layer, having a higher resistance than the electrode layer;
An organic electroluminescent device comprising: a wiring layer for supplying a current between the first reflective layer and the electrode layer.
(15)
The organic electroluminescent element according to (14), wherein the film thickness of the electrode layer is relatively thin in the pixel region and relatively thick in the region around the pixel region.

  DESCRIPTION OF SYMBOLS 1 ... organic electroluminescent element, 2 ... organic electroluminescent apparatus, 3 ... electronic device, 10 ... board | substrate, 11 ... reflection layer, 12 ... hole injection layer, 13 ... hole transport layer, 14 ... organic light emitting layer, 14A ... Light emitting area, 15: electron transport layer, 16: electron injection layer, 17: cathode, 18: film thickness adjusting layer, 19: reflecting layer, 20: display panel, 20A: pixel area, 20B: peripheral area, 21: electrode, 21A: wiring layer, 21B: electrode layer, 22, 25: bank, 23, 23R, 23G, 23B: pixel, 23-1: pixel circuit, 23-2: organic electroluminescent element, 24: color pixel, 25: bank , 28: protective layer, 30: controller, 40: driver, 41: horizontal selector, 42: light scanner, 100: organic electroluminescent element, 310: housing, 320: display surface, 410: lighting unit, 420: ceiling, 430 ... wall, Cs ... Lifting capacity, DTL ... signal line, DSL ... power supply line, Tr1 ... driving transistor, Tr2 ... write transistor, Vgs ... gate - source voltage, Vsig ... signal voltage, WSL ... scan line.

Claims (15)

A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer; The organic electroluminescent device according to claim 1, further comprising a Yb protective layer in contact with the second reflective layer side of the Ag electrode layer. The organic electroluminescent device according to claim 1, wherein the Ag electrode layer is thinner than the second reflective layer. The organic electroluminescence according to any one of claims 1 to 3, further comprising a film thickness adjusting layer having a resistance higher than that of the Ag electrode layer, between the Ag electrode layer and the second reflective layer. element. The wiring according to any one of claims 1 to 4, further comprising a wire electrically connected to the first reflective layer and the Ag electrode layer to supply a current between the first reflective layer and the Ag electrode layer. The organic electroluminescent element as described in any one. The organic electroluminescent element according to any one of claims 1 to 5, wherein the second reflective layer and the Ag electrode layer are electrically conducted. The organic electroluminescent element according to claim 6, wherein the second reflective layer and the Ag electrode layer are electrically conducted in a region not facing the light emitting region of the organic light emitting layer. The organic electroluminescent device according to any one of claims 1 to 7, wherein a distance between the first reflective layer and the second reflective layer is an optical path length in which a cavity is generated. Equipped with multiple organic electroluminescent devices,
At least one of the plurality of organic electroluminescent devices is
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer. The plurality of organic electroluminescent devices are provided in a pixel area,
The organic electroluminescent device according to claim 9, wherein the second reflective layer and the Ag electrode layer are electrically conducted in an area around the pixel area. An organic electroluminescent device having a plurality of organic electroluminescent devices,
At least one of the plurality of organic electroluminescent devices is
A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An Ag electrode layer provided between the organic light emitting layer and the second reflective layer;
An Yb electron injection layer in contact with the organic light emitting layer side of the Ag electrode layer; A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An electrode layer provided between the organic light emitting layer and the second reflective layer, the electrode layer being thinner than the second reflective layer;
A film thickness adjustment layer provided between the electrode layer and the second reflective layer, having a higher resistance than the electrode layer;
An organic electroluminescent device comprising: a wiring layer for supplying a current between the first reflective layer and the electrode layer. The organic electroluminescent device according to claim 12, wherein the second reflective layer and the electrode layer are electrically conducted in an area around a pixel area. A first reflective layer,
A second reflective layer,
An organic light emitting layer of monochromatic light emission provided between the first reflection layer and the second reflection layer;
An electrode layer provided between the organic light emitting layer and the second reflective layer;
A film thickness adjustment layer provided between the electrode layer and the second reflective layer, having a higher resistance than the electrode layer;
An organic electroluminescent device comprising: a wiring layer for supplying a current between the first reflective layer and the electrode layer. The organic electroluminescent device according to claim 14, wherein the film thickness of the electrode layer is relatively thin in the pixel region, and relatively thick in the region around the pixel region.