JP2010033984A - Organic light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic light-emitting device superior in adhesiveness of an interface between an intermediate electrode layer and an organic compound layer. <P>SOLUTION: The organic light-emitting device 1 is constituted of a lower part electrode layer 11, an upper part electrode layer 17, and a laminate that is pinched by the lower part electrode 11 and the upper part electrode layer 17, and composed of at least a first organic compound layer 12, an intermediate electrode layer (first intermediate electrode layer 13a), and a second organic compound layer 14. The first organic compound layer 12 includes at least a first light-emitting layer, the intermediate electrode layer includes an organic conductor, and the second organic compound layer 14 includes at least a second light-emitting layer. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic light-emitting device using light emission of an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element).

  As one of flat display panels, there is an organic EL display on which an organic EL element is mounted, and research and development are being actively promoted. Patent Document 1 proposes a structure in which transparent conductive layers made of an inorganic compound and a plurality of organic compound layers are alternately stacked as an organic light emitting device in which organic EL elements are stacked in the vertical direction. Patent Document 2 proposes a structure in which internal electrodes made of metal and a plurality of organic compound layers are alternately stacked.

US Pat. No. 5,707,745 Special table 2007-533073 gazette

  By the way, in the structure which laminates | stacks alternately the inorganic conductive layer and organic compound layer which consist of inorganic conductor materials, especially the inorganic conductive layer (henceforth an intermediate electrode layer) provided between an organic compound layer and an organic compound layer. Then, it is known that the linear expansion coefficient differs by about 1 to 2 digits between the inorganic conductive layer and the organic compound layer adjacent to the inorganic conductive layer. When layers having different linear expansion coefficients are laminated in this way, the intermediate electrode layer and the intermediate electrode layer are formed in a predetermined layer forming step, a patterning step for partially removing the formed layer, or a heating step after the film forming step or the patterning step. A change with time of the adhesiveness at the interface with the organic compound layer occurs. This change over time is caused by the difference in coefficient of linear expansion between the intermediate electrode layer and the organic compound layer, but this change over time may cause peeling at the interface or affect the light emission characteristics of the light emitting device. was there.

  An object of the present invention is to provide an organic light emitting device having good interface adhesion between an intermediate electrode layer and an organic compound layer.

The organic light-emitting device of the present invention includes a lower electrode layer, an upper electrode layer,
A laminate comprising at least a first organic compound layer, an intermediate electrode layer, and a second organic compound layer sandwiched between the lower electrode layer and the upper electrode layer,
The first organic compound layer includes at least a first light-emitting layer;
The intermediate electrode layer comprises an organic conductor;
The second organic compound layer includes at least a second light emitting layer.

  According to the present invention, since the thermal expansion coefficient of the intermediate electrode layer is not significantly different from that of the organic compound layer, it is possible to provide an organic light-emitting device having good adhesion at the interface between the intermediate electrode layer and the organic compound layer. .

  The organic light emitting device of the present invention comprises a lower electrode layer, an upper electrode layer, at least a first organic compound layer, an intermediate electrode layer, a second organic compound layer sandwiched between the lower electrode layer and the upper electrode layer, It is comprised from the laminated body which consists of.

  However, the intermediate electrode layer is not limited to a single layer, and a plurality of layers may be provided. When a plurality of intermediate electrode layers are provided, a separate organic compound layer is provided between the intermediate electrode layer and the intermediate electrode layer. For example, when two intermediate electrode layers are provided, the laminate sandwiched between the lower electrode layer and the upper electrode layer includes a first organic compound layer, a first intermediate electrode layer, and a second organic compound layer. And a second intermediate electrode layer and a third organic compound layer.

  Hereinafter, the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments described below.

  FIG. 1 is a cross-sectional view showing a first embodiment of the organic light-emitting device of the present invention. The organic light emitting device 1 of FIG. 1 includes a lower electrode layer 11, a first organic compound layer 12, a first intermediate electrode layer 13a, a second organic compound layer 14, and a second intermediate electrode layer 15a on a substrate 10. Then, a stacked body including the third organic compound layer 16 and the upper electrode layer 17 is formed. A protective layer 18 is formed so as to cover the upper surface and side surfaces of the laminate formed on the substrate 10. The organic light emitting device 1 in FIG. 1 includes a lower electrode layer 11 and a first intermediate electrode layer 13a, a first intermediate electrode layer 13a and a second intermediate electrode layer 15a, a second intermediate electrode layer 15a and an upper electrode. A voltage is applied to either of the layers 17. By doing so, holes injected from one electrode and electrons injected from the other electrode are recombined in the light-emitting layer included in the organic compound layer (12, 14, 16), so that light is emitted. To emit.

  In the organic light emitting device 1 of FIG. 1, the organic compound layer includes a light emitting layer. That is, the first organic compound layer 12 includes a first light emitting layer, the second organic compound layer 14 includes a second light emitting layer, and the third organic compound layer 16 includes a third light emitting layer. However, the layer structure of the organic compound layer is not limited to the light emitting layer. In addition to the light emitting layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like may be provided as necessary.

  In the organic light emitting device 1 of FIG. 1, each electrode layer (11, 13a, 15a, 17) may be composed of one layer or a plurality of layers. Here, when the intermediate electrode layer (13a, 15a) is composed of one layer, the intermediate electrode layer is a common electrode of organic compound layers adjacent vertically. On the other hand, when the intermediate electrode layer is composed of a plurality of layers, for example, a multi-layer structure such as a conductive film / insulating film / conductive film may be used so that each organic compound layer can be driven individually. .

  In the organic light emitting device 1 of FIG. 1, the protective film 18 allows moisture, oxygen, etc. contained in the outside air to enter each electrode layer (11, 13a, 15a, 17) and each organic compound layer (12, 14, 16). It is provided to block

  Next, components constituting the organic light emitting device of the present invention will be described.

  The substrate 10 is basically made of a base material to be described later. However, if necessary, the substrate 10 may be composed of this base material, a TFT circuit provided on the base material, and a planarizing layer that covers the TFT circuit and flattens the substrate. Here, a glass substrate, a Si substrate, or the like can be used as the base material.

  As a constituent material of the lower electrode layer 2 and the upper electrode layer 8, a known electrode material can be used. Specifically, a metal conductive film such as Al or Ag, a transparent conductive film such as ITO or IZO, and a laminated film obtained by laminating them can be used.

  As a constituent material of the organic compound layers (12, 14, 16), known charge transport materials (hole injection / transport materials, electron injection / transport materials) and luminescent materials can be used.

  As hole injection / transport materials, triarylamine derivatives, phenylenediamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, oxazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, oxazole derivatives, fluorenone derivatives Hydrazone derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives and poly (vinyl carbazole), poly (silylene), poly (thiophene), and other conductive polymers can be used.

  As electron injection / transport materials, oxadiazole derivatives, oxazole derivatives, thiazole derivatives, thiadiazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, perylene derivatives, quinoline derivatives, quinoxaline derivatives, fluorenone derivatives, anthrone derivatives, phenanthroline derivatives, organometallics Complexes can be used.

  As the light emitting material, a fluorescent material or a phosphorescent material can be used. Aluminum quinolinol complex, beryllium quinolinol complex, hydroxyphenyl oxazole, hydroxyphenyl thiazole, azomethine metal complex can be used.

  The intermediate electrode layers (13a, 15a) are layers containing an organic conductor. Examples of the organic conductor contained in the intermediate electrode layer include a conductive polymer, a conductive oligomer, a conductive monomer, and a conductive copolymer. The organic conductor contained in the intermediate electrode layer is preferably a conductor that can be a p-type conductor or an n-type conductor. Such a conductor becomes a p-type conductor when doped with an anion and becomes an n-type conductor when doped with a cation.

  A specific example of a conductor that can be a p-type conductor or an n-type conductor is, for example, an alternating copolymer of thiophene and quinoxaline. This alternating copolymer can be converted to a p-type conductor by reacting with an anion such as perchlorate ion. In this case, the anion reacts with the thiophene moiety. On the other hand, it can be converted into an n-type conductor by reacting with a cation such as tetraethylammonium ion. In this case, the cation reacts with a quinoxaline site (particularly, a pyridine ring site).

  Incidentally, the organic conductor can be used in a state dissolved in a solvent. The solvent used at this time is preferably a solvent that does not affect the organic compound layer in contact with the intermediate electrode layer. Specifically, hydrocarbons such as hexane and heptane, which have a low boiling point, have less influence on the organic compound layer that comes into contact with the intermediate electrode layer when forming the intermediate electrode layer. preferable. Moreover, in order to improve the solubility with respect to the hydrocarbon solvent, a substituent may be introduced into the organic conductor. For example, it is effective to introduce a hydrocarbon group such as a hexyl group into the thiophene site.

  In addition to the organic conductor, the intermediate electrode layer (13a, 15a) may contain a metal. Specific examples of this metal include cesium, lithium, aluminum, silver, and gold.

  As a constituent material of the protective film 9, a material that blocks moisture, oxygen and the like from the outside air is preferable. Specifically, silicon nitride oxide or the like is used.

  Next, a manufacturing procedure of the organic light emitting device of this embodiment will be described.

  The lower electrode layer 11 and the upper electrode layer 17 can be formed by a known method such as a sputtering method. The lower electrode layer 11 and the upper electrode layer 17 may be patterned so as to have a desired shape by a known method after the layers are formed.

  The organic compound layers (12, 14, 16) can be formed by a known method such as a vacuum deposition method.

  The intermediate electrode layers (13a, 15a) can be formed by either a wet method such as a coating method or a dry method such as a vacuum deposition method. Here, the formation method of the intermediate electrode layer can be appropriately selected depending on the molecular weight of the organic conductor which is a constituent material of the intermediate conductive layer. Specifically, if the molecular weight is several thousand or less, the film can be formed by a vacuum evaporation method, and if the molecular weight is higher than 10,000, the film can be formed by a coating method. In the intermediate electrode layer to be formed, the interface on the anode side functions as a cathode, and the interface on the cathode side functions as an anode.

  The protective layer 18 can be formed by a known method such as a CVD method.

  FIG. 2 is a cross-sectional view showing a second embodiment of the organic light emitting device of the present invention. In the following description, descriptions of the same matters as in the first embodiment may be omitted.

  The organic light emitting device 2 of FIG. 2 includes a lower electrode layer 11, a first organic compound layer 12, a first intermediate electrode layer 13b, a second organic compound layer 14, and a second intermediate electrode layer 15b on a substrate 10. Then, a stacked body including the third organic compound layer 16 and the upper electrode layer 17 is formed. A protective layer 18 is formed so as to cover the upper surface and side surfaces of the laminate formed on the substrate 10. The organic light emitting device 2 in FIG. 2 includes a lower electrode layer 11 and a first intermediate electrode layer 13b, a first intermediate electrode layer 13b and a second intermediate electrode layer 15b, a second intermediate electrode layer 15b and an upper electrode. A voltage is applied to either of the layers 17. By doing so, holes injected from one electrode and electrons injected from the other electrode are recombined in the light-emitting layer included in the organic compound layer (12, 14, 16), so that light is emitted. To emit.

  In the organic light emitting device 2 of FIG. 2, the work function of the interface on the upper electrode side of the intermediate electrode layer is different from the work function of the interface on the lower electrode side of the intermediate electrode layer. Specifically, the intermediate electrode layers (13b, 15b) constituting the organic light emitting device 2 of FIG. 2 are doped with an inorganic compound in the organic conductor constituting the layers, and therefore, the work function of the upper electrode side interface and The work function of the lower electrode side interface is adjusted to have different values. Preferably, the work function of each interface is adjusted to be a work function desirable as an anode or a cathode. Thereby, when forming an organic compound layer (12, 14, 16), formation of a hole injection layer or an electron injection layer can be omitted.

  In the organic light emitting device 2 of FIG. 2, a method for adjusting the work function of both interfaces of the intermediate electrode layers (13b, 15b) is preferably a method of including a metal in the intermediate electrode layer. In this case, the organic conductor contained in the intermediate electrode layer (13b, 15b) is preferably an organic compound that forms a coordinate bond with the metal contained in the intermediate electrode layer. Specific examples include bathophenanthroline (Bphen) and aromatic amines in which nitrogen is introduced into acenes. The metal contained in the intermediate electrode layer is preferably a typical metal, and specific examples include cesium, lithium, aluminum, silver, and gold.

  In the organic light emitting device 2 of FIG. 2, the method for forming the intermediate electrode layers (13b, 15b) is preferably a method in which an organic conductor and a metal are co-evaporated at a predetermined weight ratio. Here, when forming a thin film to be an intermediate electrode layer by co-evaporation, it is necessary to change the weight mixing ratio of the organic conductor and the metal on the way. If the weight mixing ratio is changed halfway, the work functions of both interfaces of the intermediate electrode layer can be changed. The work functions of both interfaces of the intermediate electrode layer are preferably adjusted in the range of 5 to 5.5 at the anode side interface. On the other hand, it is preferable to adjust in the range of 4 to 4.5 at the cathode interface.

[Example 1]
The organic light emitting device 1 shown in FIG. 1 was produced by the following method.

  A TFT drive circuit made of low-temperature polysilicon was formed on a glass substrate as a support, and a planarizing film made of acrylic resin was formed on the TFT drive circuit.

  Next, a silver alloy (AgPdCu) was formed on the substrate 10 by a sputtering method to form a silver alloy film. At this time, the thickness of the silver alloy film was 100 nm. Next, an IZO film was formed on the silver alloy film by sputtering. At this time, the thickness of the IZO film was set to 30 nm. The formed silver alloy film and IZO film function as an anode (lower electrode layer 11). Next, unnecessary electrode portions were removed by laser processing, and predetermined patterning was performed.

Next, the first organic compound layer 12 was formed on the anode by vacuum vapor deposition. Specifically, first, a compound I shown below was formed on the anode to form a first hole transport layer. At this time, the thickness of the first hole transport layer was set to 50 nm. Next, a compound II shown below as a host and a compound III shown below as a blue light emitting compound were co-deposited so that the weight mixing ratio was 80:20, thereby forming a first light emitting layer. At this time, the thickness of the first light emitting layer was set to 35 nm. Next, bathophenanthroline (Bphen) was formed on the first light emitting layer to form a first electron transporting layer. At this time, the thickness of the first electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-deposited on the first electron transport layer so that the weight mixing ratio was 90:10 to form a first electron injection layer. At this time, the thickness of the first electron injection layer was set to 20 nm. Thus, the first organic compound layer 12 was formed.

  Next, an alternating copolymer (n = 5) of thiophene and quinoxaline was formed on the first electron injection layer by vapor deposition to form a first intermediate electrode layer 13a. At this time, the thickness of the first intermediate electrode layer 13a was set to 800 nm.

Next, the second organic compound layer 14 was formed on the first intermediate electrode layer 13a by vacuum deposition. Specifically, first, Compound I was deposited on the first intermediate electrode layer 13a to form a second hole transport layer. At this time, the thickness of the second hole transport layer was set to 50 nm. Next, aluminum quinolinol as a host and coumarin as a green light emitting compound were co-deposited so that the weight mixing ratio was 99: 1 to form a second light emitting layer. At this time, the thickness of the second light emitting layer was set to 40 nm. Next, bathophenanthroline (Bphen) was formed on the second light emitting layer to form a second electron transport layer. At this time, the thickness of the second electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-deposited on the second electron transport layer so that the weight mixing ratio was 90:10, thereby forming a second electron injection layer. At this time, the thickness of the second electron injection layer was set to 20 nm. Thus, the second organic compound layer 14 was formed.

  Next, an alternating copolymer (n = 5) of thiophene and quinoxaline was formed on the second electron injection layer by vapor deposition to form a second intermediate electrode layer 15a. At this time, the film thickness of the second intermediate electrode layer 15a was set to 1000 nm.

Next, the third organic compound layer 16 was formed on the second intermediate electrode layer 15a by vacuum vapor deposition. Specifically, first, Compound I was deposited on the second intermediate electrode layer 15a to form a third hole transport layer. At this time, the film thickness of the third hole transport layer was 100 nm. Next, aluminum quinolinol as a host and DCM [4- (dicyanomethylene) -2-methyl-6 (p-dimethylaminostyryl) -4H-pyran] as a red light emitting compound are co-evaporated to form a third light emitting layer. Formed. At this time, the weight mixing ratio of aluminum quinolinol and DCM was 99: 1, and the thickness of the third light emitting layer was 30 nm. Next, bathophenanthroline (Bphen) was formed on the third light emitting layer to form a third electron transporting layer. At this time, the thickness of the third electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-deposited on the third electron transport layer so that the weight mixing ratio was 90:10, thereby forming a third electron injection layer. At this time, the thickness of the third electron injection layer was set to 20 nm. Thus, the third organic compound layer 16 was formed.

  Next, Ag was deposited on the third organic compound layer 16 by sputtering to form the upper electrode layer 17. At this time, the film thickness of the upper electrode layer 17 was 10 nm. Next, a protective layer 18 was formed by CVD using silicon nitride oxide so as to cover the upper electrode layer 17 and the side surface of the stacked body formed from the lower electrode layer 11 to the upper electrode layer 17. At this time, the thickness of the protective layer 18 was set to 1000 nm. Thus, an organic light emitting device was obtained.

  The following evaluation was performed about the obtained organic light-emitting device.

(1) Initial evaluation As an initial evaluation, it was confirmed whether or not the lamp was lit when a voltage of 12 V was applied.

(2) Durability test After the initial evaluation, the following durability test was performed. That is, the organic light emitting device was sequentially exposed to the following environments (i) to (iii).
(I) -30 ° C (30 minutes)
(Ii) Room temperature (5 minutes)
(Iii) 80 ° C. (30 minutes)
The above (i) to (iii) were defined as one cycle, and after 100 cycles were performed, a twist test was performed as confirmation of adhesion.

  Specifically, after pressing the organic light emitting device with a force of 49 N with a 14.9 mm diameter push-bull gauge, the pressed state was maintained for 5 seconds, and then the state of the organic light emitting device was observed with an optical microscope. As a result of observation, distortion and peeling were not seen in the organic light emitting device, and adhesion between each layer was confirmed.

(3) Evaluation of linear expansion coefficient Thin films corresponding to each organic compound layer (12, 14, 16) and each intermediate electrode layer (13a, 15a) were individually formed, and the linear expansion coefficient of each layer was evaluated. . Specifically, the linear expansion coefficient was measured for the thin film corresponding to each layer using an interferometer. As a result, it was found that the linear expansion coefficient of each layer was in the range of 300 to 700 × 10 ⁻⁷ cm / cm · ° C. For this reason, it was found that the linear expansion coefficient of the intermediate electrode layer was not significantly different from that of the organic compound layer.

[Example 2]
The organic light emitting device 2 shown in FIG. 2 was produced by the following method.

  A TFT drive circuit made of low-temperature polysilicon was formed on a glass substrate as a support, and a planarizing film made of acrylic resin was formed on the TFT drive circuit.

  Next, a silver alloy (AgPdCu) was formed on the substrate 10 by a sputtering method to form a silver alloy film. At this time, the thickness of the silver alloy film was 100 nm. Next, an IZO film was formed on the silver alloy film by sputtering. At this time, the thickness of the IZO film was set to 30 nm. The formed silver alloy film and IZO film function as an anode (lower electrode layer 11). Next, unnecessary electrode portions were removed by laser processing, and predetermined patterning was performed.

  Next, a first organic compound layer was formed on the lower electrode layer 11 by vacuum vapor deposition. Specifically, first, Compound I was deposited on the lower electrode layer 11 to form a first hole transport layer. At this time, the thickness of the first hole transport layer was set to 50 nm. Next, on the first hole transport layer, the compound II as a host and the compound III as a blue light-emitting compound were co-evaporated so as to have a weight mixing ratio of 80:20 to form a first light-emitting layer. . At this time, the thickness of the first light emitting layer was set to 35 nm. Thus, the first organic compound layer 12 was formed.

Next, a first electrode layer was formed by co-evaporating Bphen and Cs ₂ CO ₃ on the first light emitting layer by a vacuum deposition method so that the weight mixing ratio was 90:10. At this time, the thickness of the first electrode layer was 100 nm. Next, a second electrode layer was formed on the first electrode layer by co-evaporation of Bphen and Cs ₂ CO _{3 so as} to have a weight mixing ratio of 98: 2 by vacuum deposition. At this time, the thickness of the second electrode layer was set to 100 nm. The first electrode layer and the second electrode layer function as the first intermediate electrode layer 13b. The work function of the interface between the first electrode layer and the first light emitting layer is 4.5, and the work function of the interface between the second electrode layer and the second hole transport layer described later is 5.5. is there. Furthermore, the first electrode layer functions as a cathode, and the second electrode layer functions as an anode.

  Next, a second organic compound layer was formed on the first intermediate electrode layer 13b by vacuum deposition. Specifically, first, Compound I was deposited on the first intermediate electrode layer 13b to form a second hole transport layer. At this time, the thickness of the second hole transport layer was set to 50 nm. Next, on the second hole transport layer, aluminum quinolinol as a host and coumarin as a green light emitting compound were co-deposited so that the weight mixing ratio was 99: 1 to form a second light emitting layer. At this time, the thickness of the second light emitting layer was set to 40 nm. Thus, the second organic compound layer 14 was formed.

Next, a third electrode layer was formed on the second light emitting layer by co-evaporation of Bphen and Cs ₂ CO _{3 so as} to have a weight mixing ratio of 90:10 by vacuum deposition. At this time, the thickness of the third electrode layer was 100 nm. Next, a fourth electrode layer was formed by co-evaporating Bphen and Cs ₂ CO ₃ on the third electrode layer by a vacuum deposition method so that the weight mixing ratio was 98: 2. At this time, the thickness of the fourth electrode layer was 100 nm. The third electrode layer and the fourth electrode layer function as the second intermediate electrode layer 15b. The work function of the interface between the third electrode layer and the second light emitting layer is 4.5, and the work function of the interface between the fourth electrode layer and a third hole transport layer described later is 5.5. is there. Furthermore, the third electrode layer functions as a cathode, and the fourth electrode layer functions as an anode.

Next, a third organic compound layer was formed on the second intermediate electrode layer 15b by vacuum deposition. Specifically, first, a compound I was formed on the second intermediate electrode layer 15b to form a third hole transport layer. At this time, the film thickness of the third hole transport layer was 100 nm. Next, on the third hole transporting layer, aluminum quinolinol as a host and DCM as a red light emitting compound were co-evaporated so that the weight mixing ratio was 99: 1 to form a third light emitting layer. At this time, the thickness of the third light emitting layer was set to 30 nm. Next, bathophenanthroline (Bphen) was formed on the third light-emitting layer by a vacuum deposition method to form an electron transport layer. At this time, the thickness of the electron transport layer was 20 nm. Next, an electron injection layer was formed by co-evaporating Bphen and Cs ₂ CO ₃ on the electron transport layer by a vacuum deposition method so that the weight mixing ratio was 90:10. At this time, the thickness of the electron injection layer was set to 20 nm. Thus, the third organic compound layer 16 was formed.

  Next, Ag was deposited on the electron injection layer by sputtering to form the upper electrode 17. At this time, the film thickness of the upper electrode layer 17 was 10 nm. Next, a protective layer 18 was formed by depositing silicon nitride oxide over the upper electrode layer 17 and the side surface of the stacked body formed from the lower electrode layer 11 to the upper electrode layer 17 by CVD. At this time, the thickness of the protective layer 18 was set to 1000 nm. Thus, an organic light emitting device was obtained.

The obtained organic light emitting device was evaluated in the same manner as in Example 1. As a result, in the durability test, no distortion or peeling was observed in the organic light-emitting device, and adhesion between layers was confirmed. Moreover, since the linear expansion coefficient of each layer was in the range of 300 to 700 × 10 ⁻⁷ cm / cm · ° C., it was found that the linear expansion coefficient of the intermediate electrode layer was not significantly different from that of the organic compound layer.

[Comparative Example 1]
The organic light emitting device 3 shown in FIG. 3 was produced by the following method.

  A TFT drive circuit made of low-temperature polysilicon was formed on a glass substrate as a support, and a planarizing film made of acrylic resin was formed on the TFT drive circuit.

  Next, a silver alloy (AgPdCu) was formed on the substrate 10 by a sputtering method to form a silver alloy film. At this time, the thickness of the silver alloy film was 100 nm. Next, an IZO film was formed on the silver alloy film by sputtering. At this time, the thickness of the IZO film was set to 30 nm. The formed silver alloy film and IZO film function as an anode (lower electrode layer 11). Next, unnecessary electrode portions were removed by laser processing, and predetermined patterning was performed.

Next, the first organic compound layer 12 was formed on the anode by vacuum vapor deposition. Specifically, first, a compound I shown below was formed on the anode to form a first hole transport layer. At this time, the thickness of the first hole transport layer was set to 50 nm. Next, the following compound II, which is a host, and compound III, which is a blue light-emitting compound, were co-deposited so that the weight mixing ratio was 80:20, thereby forming a first light-emitting layer. At this time, the thickness of the first light emitting layer was set to 35 nm. Next, bathophenanthroline (Bphen) was formed on the first light emitting layer to form a first electron transporting layer. At this time, the thickness of the first electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-deposited on the first electron transport layer so that the weight mixing ratio was 90:10 to form a first electron injection layer. At this time, the thickness of the first electron injection layer was set to 20 nm. Thus, the first organic compound layer 12 was formed.

  Next, an IZO film was formed on the first electron injection layer by sputtering to form a first intermediate electrode layer 13c. At this time, the thickness of the first intermediate electrode layer 13c was set to 70 nm.

Next, the second organic compound layer 14 was formed on the first intermediate electrode layer 13c by vacuum deposition. Specifically, first, Compound I was deposited on the first intermediate electrode layer 13c to form a second hole transport layer. At this time, the thickness of the second hole transport layer was set to 50 nm. Next, aluminum quinolinol as a host and coumarin as a green light emitting compound were co-deposited so that the weight mixing ratio was 99: 1 to form a second light emitting layer. At this time, the thickness of the second light emitting layer was set to 40 nm. Next, bathophenanthroline (Bphen) was formed on the second light emitting layer to form a second electron transport layer. At this time, the thickness of the second electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-evaporated on the second electron transport layer so that the weight mixing ratio was 90:10, thereby forming a second electron injection layer. At this time, the thickness of the second electron injection layer was set to 20 nm. Thus, the second organic compound layer 14 was formed.

  Next, an IZO film was formed on the second electron injection layer by sputtering to form a second intermediate electrode layer 15c. At this time, the thickness of the second intermediate electrode layer 15c was set to 70 nm.

Next, the third organic compound layer 16 was formed on the second intermediate electrode layer 15c by vacuum deposition. Specifically, first, Compound I was deposited on the second intermediate electrode layer 15c to form a third hole transport layer. At this time, the film thickness of the third hole transport layer was 100 nm. Next, aluminum quinolinol as a host and DCM as a red light emitting compound were co-evaporated so that the weight mixing ratio was 99: 1 to form a third light emitting layer. At this time, the thickness of the third light emitting layer was set to 30 nm. Next, bathophenanthroline (Bphen) was formed on the third light emitting layer to form a third electron transporting layer. At this time, the thickness of the third electron transport layer was set to 20 nm. Next, Bphen and Cs ₂ CO ₃ were co-deposited on the third electron transport layer so that the weight mixing ratio was 90:10, thereby forming a third electron injection layer. At this time, the thickness of the third electron injection layer was set to 20 nm. Thus, the third organic compound layer 16 was formed.

  Next, Ag was deposited on the third organic compound layer 16 by sputtering to form the upper electrode layer 17. At this time, the film thickness of the upper electrode layer 17 was 10 nm. Next, a protective layer 18 was formed by CVD using silicon nitride oxide so as to cover the upper electrode layer 17 and the side surface of the stacked body formed from the lower electrode layer 11 to the upper electrode layer 17. At this time, the thickness of the protective layer 18 was set to 1000 nm. Thus, an organic light emitting device was obtained.

The obtained organic light emitting device was evaluated in the same manner as in Example 1. As a result, several peeling points were found between the organic compound layer and the intermediate electrode layer in the durability test. The linear expansion coefficient of each layer is such that each organic compound layer is in the range of 300 to 700 × 10 ⁻⁷ cm / cm · ° C., whereas the intermediate electrode layer (IZO electrode layer) is 40 to 50 × 10 ⁻ It was found to be ⁷ cm / cm · ° C. As a result, it was found that an intermediate electrode layer having a linear expansion coefficient different by one digit from that of the organic compound layer was formed.

It is sectional drawing which shows 1st embodiment in the organic light-emitting device of this invention. It is sectional drawing which shows 2nd embodiment in the organic light-emitting device of this invention. 6 is a cross-sectional view showing an organic light emitting device manufactured in Comparative Example 1. FIG.

Explanation of symbols

1, 2, 3 Organic light emitting device 10 Substrate 11 Lower electrode layer (anode)
12 1st organic compound layer 13a, 13b, 13c 1st intermediate electrode layer 14 2nd organic compound layer 15a, 15b, 15c 2nd intermediate electrode layer 16 3rd organic compound layer 17 Upper electrode layer 18 Protective layer

Claims (3)

A lower electrode layer and an upper electrode layer;
A laminate comprising at least a first organic compound layer, an intermediate electrode layer, and a second organic compound layer sandwiched between the lower electrode layer and the upper electrode layer,
The first organic compound layer includes at least a first light-emitting layer;
The intermediate electrode layer comprises an organic conductor;
The organic light emitting device, wherein the second organic compound layer includes at least a second light emitting layer.   2. The organic light emitting device according to claim 1, wherein a work function of an interface on the upper electrode side of the intermediate electrode layer is different from a work function of an interface on the lower electrode side of the intermediate electrode layer.   The organic light emitting device according to claim 1, wherein the intermediate electrode layer further contains a metal.

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