JP6209964B2 - Method for manufacturing organic electroluminescence device - Google Patents

Description

The present invention relates to the production how the organic electroluminescent device.

In recent years, organic electroluminescence elements (hereinafter referred to as “organic EL elements” as appropriate) have attracted attention as self-luminous elements.
For this organic EL element, various inventions have been created so far. For example, a base material using a flexible resin that is lightweight and has a high degree of freedom in shape as a base material of the organic EL element. Has been created. And with the advent of such a flexible base material, a roll-to-roll manufacturing method has been adopted as a method for manufacturing an organic EL element.

Since this roll-to-roll organic EL element manufacturing method allows continuous production of organic EL elements and can improve production efficiency, research and development on the manufacturing method has been promoted.
Specifically, the following proposals have been made on a method for manufacturing a roll-to-roll organic EL element.

  For example, Patent Document 1 discloses a method for forming a light-emitting layer and a cathode under vacuum on a substrate on which an anode has been patterned in advance, as a method for producing an organic EL element by a roll-to-roll method.

  Patent Document 2 discloses a method of using a guide roll mechanism having a predetermined structure as a method of manufacturing an organic EL element for preventing the generation of scratches on a substrate or an organic EL laminate.

International Publication No. 01/005194 JP 2009-256709 A

The technique disclosed in Patent Document 1 or Patent Document 2 is based on a roll-to-roll method in a vacuum atmosphere in which an organic functional layer, a cathode (second electrode), and the like are formed on a substrate on which an anode (first electrode) has been formed in advance. It is formed. That is, the process of forming an anode with respect to a base material and the process of forming an organic functional layer, a cathode, etc. are performed on different production lines.
Therefore, according to the technique disclosed in Patent Document 1 or Patent Document 2, the electrode is exposed to the atmospheric environment after the step of forming the first electrode (electrode) on the base material. There was a possibility of deteriorating and there was a possibility of particles adhering to the electrode surface. As a result, there is a possibility that the luminance and the light emission efficiency are lowered due to the deterioration of the electrode, and the leakage is caused by the adhesion of particles to the electrode surface.

In view of such circumstances, the present invention provides a method for producing an organic electroluminescence device capable of preventing a decrease in luminance and light emission efficiency due to electrode deterioration and occurrence of leakage due to adhesion of particles to the electrode surface. The challenge is to provide a law .

  That is, the said subject of this invention is solved by the following structure.

1. A first electrode forming step of forming a first electrode on a substrate, an organic functional layer forming step of forming an organic functional layer including a light emitting layer so as to be laminated on the first electrode, and a lamination on the organic functional layer and a second electrode forming step of forming a second electrode, a containing Mutotomoni, before the first electrode forming step, removal for energizing the extraction electrode and the second electrode for energizing the first electrode Extraction electrode forming step of forming at least one of the electrodes on the base material, and before the extraction electrode formation step, the base material is dry-washed and the base material has a moisture concentration of 500 ppm or less It includes a cleaning step of drying, a further step from the washing and drying step to the second electrode forming step, the organic electroluminescent cell which comprises carrying out in a vacuum atmosphere by a roll-to-roll Manufacturing method of the scan element.

2 . After the second electrode forming step, the method further includes a sealing step of sealing what is formed on the substrate, and the steps up to the sealing step are performed in a vacuum atmosphere by a roll-to-roll method. 2. The method for producing an organic electroluminescence device according to 1 above, wherein

3 . 3. The method of manufacturing an organic electroluminescence element according to 1 or 2 , wherein the first electrode and the extraction electrode are formed by sputtering and are patterned using a mask at the time of formation.

According to the present invention, to provide lowering of luminance and luminous efficiency due to the deterioration of the electrode, producing how the organic electroluminescent device capable of preventing occurrence of leakage due to adhesion of particles to the electrode surface Can do.

It is a flowchart of the manufacturing method of the organic EL element which concerns on embodiment of this invention. It is a schematic diagram of the pre-processing line for implementing a pre-processing process. (A) And (b) is a schematic diagram of the vacuum line for implementing the process from a washing-drying process to a sealing process.

  First, the manufacturing method of the organic electroluminescent element which concerns on embodiment of this invention is demonstrated, referring drawings suitably.

[Method of manufacturing organic EL element]
As shown in FIG. 1, the method for manufacturing an organic EL device according to the embodiment of the present invention includes a first electrode forming step S3, an organic functional layer forming step S4, and a second electrode forming step S5. The steps from the electrode forming step S3 to the second electrode forming step S5 are performed in a vacuum atmosphere by a roll-to-roll method.

  Moreover, as shown in FIG. 1, the manufacturing method of the organic EL element according to the embodiment of the present invention further includes a cleaning / drying step S1 and a extraction electrode forming step S2, and after the cleaning / drying step S1 and the extraction electrode forming step S2. The process is preferably performed in a vacuum atmosphere by a roll-to-roll method. Moreover, it is preferable that the sealing process S6 is further included and the processes up to the sealing process S6 are performed in a vacuum atmosphere by a roll-to-roll method.

  That is, the manufacturing method of the organic EL element according to the embodiment of the present invention includes at least the steps from the first electrode forming step S3 to the second electrode forming step S5 (preferably after the cleaning / drying step S1 or the extraction electrode forming step S2, Or the sealing process S6) is a manufacturing method in which a series of processes are performed in a vacuum atmosphere in one line (plant or apparatus) without being exposed to an atmospheric environment.

  And the manufacturing method of the organic EL element which concerns on embodiment of this invention may include pre-processing process S0 before the above-mentioned series of processes performed in a vacuum atmosphere, and post-processing after the above-mentioned series of processes. Step S7 may be included.

Here, the “roll-to-roll method” means that a flexible base material wound in a roll shape is fed out and subjected to predetermined treatment such as washing and drying while being intermittently or continuously conveyed, or an electrode Or after laminating a predetermined layer, the substrate is again wound around a roll.
Also, depending on the configuration of the process, it may be considered that the flexible base material is cut into a sheet shape without being wound up and sent to the next process, but this is also included in the “roll-to-roll system”.

Further, the “under vacuum atmosphere” means a pressure atmosphere lower than atmospheric pressure, preferably 1 × 10 ⁻³ Pa or less, more preferably 1 × 10 ⁻⁵ Pa or less.

Next, each process of the manufacturing method of the organic EL element which concerns on embodiment of this invention is demonstrated.
(Pretreatment process)
The pretreatment step is a step of performing pretreatment such as dry washing / wet washing, drying, and protective sheet laminating on the substrate before the electrode / organic functional layer and the like are formed.
About the method of each process in this pre-processing process, what is necessary is just to use a well-known processing method.
Note that the pretreatment process may be performed in an atmospheric pressure atmosphere.

Then, as shown in FIG. 2, the preprocessing step S0 is performed on the preprocessing line 100.
Specifically, in the pretreatment step S0, first, in the delivery chamber 101, the belt-like base material 11 (gas barrier film formed) is delivered from the roll 11a. In the delivery chamber 101, when the protective sheet 12 is affixed, the protective sheet 12 is peeled off from the base material 11. Then, the fed substrate 11 is dry cleaned in the dry cleaning chamber 102 by UV (ultraviolet) irradiation or oxygen plasma irradiation. Then, the base material 11 is wet cleaned in the wet cleaning chamber 103 using scrub cleaning using ultrapure water or the like. The substrate 11 is dried in the drying chamber 104 by IR (infrared) irradiation, hot air blowing, or the like. And the protective sheet 13 is affixed on the base material 11 in the lamination chamber 105. FIG. Then, the base material 11b to which the protective sheet 13 is attached is wound around the roll 11c in the winding chamber 106.

(Washing and drying process)
The cleaning / drying step is a step of performing dry cleaning on the substrate surface and removing moisture in the substrate.
About the cleaning method of the substrate surface in this cleaning / drying step, it may be cleaned (dry cleaning) by a known cleaning method such as UV (ultraviolet) irradiation or oxygen plasma irradiation. Also, the substrate drying method in the washing and drying step may be dried by a known drying method such as IR (infrared) irradiation.
In this washing and drying step, it is preferable to dry the substrate until the water concentration becomes about 500 ppm or less. This is because it is possible to reliably avoid a situation where the vacuum state deteriorates (the degree of vacuum decreases) in the subsequent steps.

As shown in FIG. 3, the cleaning / drying step S <b> 1 is performed in the cleaning / drying chamber 203 of the vacuum line 200.
Specifically, first, in the delivery chamber 201 of the vacuum line 200, the base material 11 is delivered from the roll 11c. In the delivery chamber 201, the protective sheet 13 is peeled off from the base material 11. Then, the fed substrate 11 is subjected to the cleaning process and the drying process in the above-described cleaning and drying step S1 in the cleaning and drying chamber 202.
The washing treatment and the drying treatment are preferably continuous treatment in the air in consideration of easiness of heat treatment and wet washing.
Note that the cleaning / drying chamber 202 may be separated into a cleaning chamber and a drying chamber.

(Extraction electrode formation process)
The extraction electrode forming step is a step of forming on the substrate at least one of an extraction electrode for energizing the first electrode and an extraction electrode for energizing the second electrode.
As a method for forming the extraction electrode (film formation method) in the extraction electrode formation step, a known film formation method may be used. However, the film formation method of the extraction electrode is preferably sputtering or vapor deposition, and depending on the material of the extraction electrode to be formed, sputtering is particularly preferable from the viewpoint that the film formation can generally be performed accurately.
In order to form the extraction electrode in a predetermined pattern, it is preferable to use a predetermined mask at the time of film formation. The same applies to various electrodes and organic functional layers described later.

As shown in FIG. 3, the extraction electrode formation step S <b> 2 is performed in the extraction electrode formation chamber 204 of the vacuum line 200.
Specifically, after the cleaning / drying step S1, the base material 11 sent out from the cleaning / drying chamber 202 passes through the auxiliary transfer chamber 203 provided so as to be intermittently transferred, and the extraction electrode forming chamber 204. The above-described extraction electrode forming step S2 is performed.

(First electrode forming step)
A 1st electrode formation process is a process of forming a 1st electrode on a base material.
As a first electrode forming method (film forming method) in the first electrode forming step, a known film forming method may be used. However, the film formation method of the first electrode is preferably sputtering or vapor deposition as in the case of the film formation method of the extraction electrode. Although it depends on the material of the first electrode to be formed, generally the film formation can be performed precisely. Sputtering is particularly preferable from the viewpoint that it can be performed.

As shown in FIG. 3, the first electrode formation step S <b> 3 is performed in the first electrode formation chamber 206 of the vacuum line 200.
Specifically, after the extraction electrode formation step S2, the base material 11 fed out from the extraction electrode formation chamber 204 passes through the auxiliary transfer chamber 205 provided so as to absorb the difference between the front and rear processing speeds, and the first In the electrode forming chamber 206, the above-described first electrode forming step S3 is performed.

(Organic functional layer formation process)
An organic functional layer formation process is a process of forming the organic functional layer containing a light emitting layer so that it may laminate | stack on a base material (1st electrode).
About the formation method of the organic functional layer in this organic functional layer formation process, what is necessary is just to form by a well-known formation method, for example, vapor deposition, application | coating.

As shown in FIG. 3, the organic functional layer forming step S <b> 4 is performed in the organic functional layer forming chamber 208 of the vacuum line 200.
Specifically, after the first electrode formation step S3, the base material 11 sent out from the first electrode formation chamber 206 passes through the auxiliary transfer chamber 207 provided to absorb the difference between the front and rear processing speeds, In the organic functional layer forming chamber 208, the above-described organic functional layer forming step S4 is performed.
As will be described later, since the organic functional layer is usually composed of a plurality of layers, there are also a plurality of organic functional layer forming chambers 208 for laminating the plurality of organic functional layers. In each chamber 208, organic functional layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, and an electron injection layer are formed to be laminated. Instead of forming one organic functional layer in each organic functional layer forming chamber, a stack of a plurality of organic functional layers may be formed in one organic functional layer forming chamber.

(Second electrode forming step)
A 2nd electrode formation process is a process of forming a 2nd electrode so that it may laminate | stack on a base material (organic functional layer).
The formation method of the second electrode in the second electrode formation step is not particularly limited, and may be formed by a known formation method, for example, vapor deposition.

As shown in FIG. 3, the second electrode formation step S <b> 5 is performed in the second electrode formation chamber 210 of the vacuum line 200.
Specifically, after the organic functional layer forming step S4, the base material 11 sent out from the organic functional layer forming chamber 208 passes through the auxiliary transfer chamber 209 provided so as to absorb the difference between the front and rear processing speeds, In the second electrode formation chamber 210, the above-described second electrode formation step S5 is performed.

(Sealing process)
The sealing step is a step of sealing at least part of the first electrode, the organic functional layer, and the second electrode formed on the substrate so as not to be affected by moisture or the like.
The sealing method in this sealing step is a known sealing method, for example, if a sealing member such as a PET film with a gas barrier layer to which a sealing resin (adhesive) is applied is applied from above the second electrode. Good.

And as shown in FIG. 3, sealing process S6 is performed in the lamination chamber 212 of the vacuum line 200. FIG.
Specifically, after the second electrode formation step S5, the base material 11 sent out from the second electrode formation chamber 210 passes through the auxiliary transfer chamber 211 provided so as to absorb the difference between the front and rear processing speeds, In the laminating chamber 212, a process such as attaching the sealing member 14 is performed.

(Post-processing process)
The post-processing step is a heat treatment for main-curing the sealing resin (adhesive) applied to the sealing member after the sealing step, or cutting to cut the substrate into a sheet of a predetermined size This is a step of performing post-processing such as processing. The post-treatment process is preferably performed in the atmosphere from the viewpoint of ease of heat treatment and countermeasures against dust generated by cutting.

[Modification]
The manufacturing method of the organic EL element according to the embodiment of the present invention is as described above. However, in carrying out the present invention, other processes may be performed between or before and after each process within a range that does not adversely affect each process. These steps may be included.
For example, at least part of the first electrode, the organic functional layer, and the second electrode formed on the substrate so as not to be affected by moisture between the second electrode forming step S5 and the sealing step S6 are chemically A film sealing step of forming an inorganic film or the like by vapor deposition (CVD) or the like may be performed.

  As shown in FIG. 3, the vacuum line 200 is provided with a plurality of auxiliary transfer chambers 203, 205, 207, 209, 211, and 213 so that intermittent transfer is possible. The number and scale of the chambers (the number of rollers inside) may be changed as appropriate.

  Moreover, although the manufacturing method of the organic EL element which concerns on embodiment of this invention illustrated and demonstrated the manufacturing method of the organic EL element provided with the organic functional layer of 1 stack, organic EL provided with the organic functional layer of several stacks Of course, the present invention can also be applied to an element manufacturing method. In this case, an intermediate electrode layer forming step is provided after the organic functional layer forming step S4 so that an intermediate electrode layer is formed between the stacks, and a second organic functional layer forming step is further provided. do it.

Moreover, you may perform extraction electrode formation process S2 after 1st electrode formation process S3. In this case as well, the extraction electrode forming step S2 is a step between the first electrode forming step S3 and the second electrode forming step S5, so that it is performed in a vacuum atmosphere by a roll-to-roll method. Become.
Moreover, you may perform an above described post-processing process by a roll-to-roll system in a vacuum atmosphere.

  In the respective steps of the method for manufacturing an organic EL element according to the embodiment of the present invention, conventionally known conditions may be used for conditions that are not clearly shown, and the conditions are appropriately set as long as the obtained effect is obtained. Needless to say, it can be changed.

According to the method for manufacturing an organic EL element according to the embodiment of the present invention, the steps from the first electrode forming step to the second electrode forming step are performed in a vacuum atmosphere by a roll-to-roll method. The formed substrate can be prevented from being exposed to the atmospheric environment. Therefore, it is possible to prevent the first electrode from deteriorating due to exposure to the atmospheric environment and to prevent particles from adhering to the first electrode.
As a result, according to the manufacturing method of the organic EL element according to the embodiment of the present invention, it is possible to prevent a decrease in luminance and light emission efficiency due to the deterioration of the first electrode and a leak due to the adhesion of particles to the surface of the first electrode. It is possible to manufacture an organic electroluminescence device that can be used.
In addition, according to the manufacturing method of the organic EL element which concerns on embodiment of this invention, when using materials (a metal, an alloy, etc.) which are easy to oxidize when exposed to an atmospheric environment as a 1st electrode, Compared with the conventional manufacturing method of an organic EL element, a particularly remarkable deterioration preventing effect is exhibited.

In addition, according to the manufacturing method of the conventional organic EL element, there is a possibility that particles adhere to the surface of the first electrode by exposing the base material on which the first electrode is formed in advance to the atmospheric environment. When trying to remove the particles, hard (strong) cleaning of the surface of the first electrode is required. On the other hand, according to the method for manufacturing an organic EL element according to the embodiment of the present invention, the possibility of particles adhering to the surface of the first electrode is very low, and thus the hard cleaning is not necessary. In addition, in the method for manufacturing an organic EL element according to the embodiment of the present invention, it is preferable to perform cleaning (dry cleaning, wet cleaning) in the pretreatment step. However, the cleaning is performed on the substrate instead of the first electrode. In addition, soft cleaning is used instead of hard cleaning as described above.
Therefore, according to the method for manufacturing an organic EL element according to the embodiment of the present invention, a hard cleaning operation that may damage the first electrode is not necessary. Therefore, even if it considers the point which can exclude a hard cleaning operation, it can be said that the manufacturing method of the organic EL element concerning the embodiment of the present invention is excellent in the point of prevention of degradation of the 1st electrode.

  In addition, according to the method for manufacturing an organic EL element according to the embodiment of the present invention, the extraction electrode formation step is also performed in a vacuum atmosphere by a roll-to-roll method. In addition, it is possible to manufacture an organic electroluminescence element that can prevent the occurrence of leakage due to adhesion of particles to the surface of the extraction electrode.

  Moreover, according to the manufacturing method of the organic EL element which concerns on embodiment of this invention, since it carries out in a vacuum atmosphere by a roll-to-roll system also about a washing-drying process, the dust etc. (for example, pre-processing process) of a base-material surface After peeling off the protective sheet affixed in (1), the adhesive etc. remaining on the surface of the substrate can be removed. In addition, by removing water in the substrate to some extent, it is possible to avoid a situation in which the vacuum state is deteriorated (the degree of vacuum is reduced) due to the water contained in the substrate.

  Moreover, according to the manufacturing method of the organic EL element which concerns on embodiment of this invention, since a sealing process is performed in a vacuum atmosphere by a roll-to-roll system, on a base material in the process to a 2nd electrode formation process. The formed electrode and organic functional layer can be reliably sealed in a vacuum atmosphere. Therefore, protection of an electrode and an organic functional layer can be ensured.

  In addition, according to the method for manufacturing an organic EL element according to the embodiment of the present invention, the first electrode and the extraction electrode are formed by sputtering, and therefore, the first electrode and the extraction electrode are formed very precisely. Can do.

Next, the organic EL element manufactured by the method for manufacturing the organic EL element according to the embodiment of the present invention will be described.
[Organic EL device]
The organic EL element is configured by laminating a first electrode (anode), an organic functional layer including a light emitting layer, a second electrode (cathode), and the like on a base material.
The organic functional layer has various functions such as a carrier (hole and electron) injection layer, a blocking layer, and a transport layer, in addition to the basic organic functional layer directly related to light emission, which is a light emitting layer. An organic functional layer may be provided.

In the organic EL element, preferred examples of the organic functional layer are as follows. In the following (1) to (6), the layer described above is usually provided on the first electrode (anode) side, and is then laminated on the second electrode (cathode) side in the order described below. The
(1) Light emitting layer / electron transport layer (2) Hole transport layer / light emitting layer / electron transport layer (3) Hole transport layer / light emitting layer / hole blocking layer / electron transport layer (4) Hole transport layer / Light emitting layer / hole blocking layer / electron transport layer / electron injection layer (cathode buffer layer) (5) hole injection layer (anode buffer layer) / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / Electron injection layer (6) Hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer

  Hereinafter, each part which comprises an organic EL element is demonstrated. However, the configuration of the organic EL element is not limited to the following contents.

(Base material)
The substrate is preferably composed of a flexible substrate such as a resin. In addition, when using resin as a base material, it is preferable that the gas barrier layer described below is formed in the surface of a resin sheet.

(Gas barrier layer)
It is preferable that one or two or more gas barrier layers are formed between the base material and the organic functional layer from the viewpoint of moisture resistance.

  The material for forming the gas barrier layer is not particularly limited, and examples thereof include an inorganic film, an organic film, or a hybrid film of both. A material having a function of suppressing entry of an element that causes deterioration of the element such as moisture or oxygen is preferable. For example, a metal oxide such as silicon oxide or silicon dioxide, a metal nitride such as silicon nitride, or the like can be used. Furthermore, in order to further improve the strength of the gas barrier layer, it is preferable to have a layered structure of an inorganic layer and an organic layer. The order in which the inorganic layer and the organic layer are stacked is not particularly limited, but it is preferable to stack the layers alternately a plurality of times.

(First electrode)
The first electrode (anode) is an electrode film that supplies (injects) holes to the organic functional layer (specifically, the light emitting layer). The material type and physical properties of the first electrode are not particularly limited and can be set arbitrarily. For example, the first electrode can be formed of a material having a high work function (4 eV or more), for example, an electrode material such as a metal, an alloy, an electrically conductive compound, and a mixture thereof. The first electrode may be made of a light-transmitting material (transparent electrode) such as indium tin oxide (ITO) or indium zinc oxide.

  The sheet resistance as the first electrode (anode) is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

(Organic functional layer)
Various organic functional layers constituting the organic functional layer will be described below, but since specific materials of each organic functional layer of these organic functional layers can be applied with known materials, the description Is omitted.

<Light emitting layer>
The light emitting layer is directly injected from the first electrode or from the first electrode through the hole transport layer and the like, and directly from the second electrode (cathode) or from the second electrode through the electron transport layer or the like. This is a layer that emits light by recombination with the injected electrons. Note that the portion that emits light may be inside the light emitting layer, or may be an interface between the light emitting layer and a layer adjacent thereto.

  The light emitting layer is preferably formed of an organic light emitting material including a host compound (host material) and a light emitting material (light emitting dopant compound). When the light emitting layer is configured in this way, an arbitrary emission color can be obtained by appropriately adjusting the emission wavelength of the light emitting material, the type of the light emitting material to be contained, and the like. In addition, by configuring the light emitting layer in this way, light can be emitted from the light emitting material in the light emitting layer.

  The total thickness of the light emitting layers can be set as appropriate according to desired light emission characteristics and the like. For example, the total thickness of the light emitting layer is 1 nm or more and 200 nm or less from the viewpoints of uniformity of the light emitting layer, prevention of unnecessary application of a high voltage during light emission, and improvement of stability of light emission color with respect to driving current. It is preferable to do. In particular, from the viewpoint of a low driving voltage, the total thickness of the light emitting layers is preferably 30 nm or less.

  The host compound contained in the light emitting layer is preferably a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of 0.1 or less, and more preferably 0.01 or less. The volume ratio of the host compound in the light emitting layer is preferably 50% or more of various compounds contained in the light emitting layer.

  As the light-emitting material contained in the light-emitting layer, for example, a phosphorescent light-emitting material (phosphorescent compound or phosphorescent compound), a fluorescent light-emitting material, or the like can be used. Note that one light emitting layer may contain one kind of light emitting material, or may contain a plurality of kinds of light emitting materials having different light emission maximum wavelengths. By using a plurality of types of light emitting materials, a plurality of lights having different emission wavelengths can be mixed to emit light, whereby light of any emission color can be obtained. Specifically, for example, white light can be obtained by including a blue light emitting material, a green light emitting material, and a red light emitting material (three kinds of light emitting materials) in the light emitting layer.

<< Injection layer (hole injection layer, electron injection layer) >>
The injection layer is a layer for reducing the drive voltage and improving the light emission luminance. The injection layer is usually provided between the electrode and the light emitting layer. The injection layer is generally roughly divided into two. That is, the injection layer is roughly classified into a hole injection layer that injects holes (carriers) and an electron injection layer that injects electrons (carriers). The hole injection layer (anode buffer layer) is provided between the first electrode and the light emitting layer or the hole transport layer. The electron injection layer (cathode buffer layer) is provided between the second electrode and the light emitting layer or the electron transport layer.

《Blocking layer (hole blocking layer, electron blocking layer)》
The blocking layer is a layer for blocking the transport of carriers (holes, electrons). The blocking layer is generally roughly divided into two. That is, the blocking layer is broadly classified into a hole blocking layer that blocks hole (carrier) transport and an electron blocking layer that blocks electron (carrier) transport.

  The hole blocking layer is a layer having the function of an electron transport layer (electron transport function) described later in a broad sense. The hole blocking layer is formed of a material having an electron transport function and a small hole transport capability. By providing such a hole blocking layer, the injection balance between holes and electrons in the light emitting layer can be made suitable. Thereby, the recombination probability of electrons and holes can be improved.

  In addition, as a hole-blocking layer, the structure of the electron carrying layer mentioned later is applicable similarly as needed. Further, when a hole blocking layer is provided, the hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer is a layer having a function of a hole transport layer (hole transport function) described later in a broad sense. The electron blocking layer is formed of a material having a hole transport function and a small electron transport capability. By providing such an electron blocking layer, the injection balance between holes and electrons in the light emitting layer can be made favorable. Thereby, the recombination probability of electrons and holes can be improved. In addition, as an electron blocking layer, the structure of the positive hole transport layer mentioned later is similarly applicable as needed.

  The thickness of the blocking layer is not particularly limited, but is preferably 3 nm or more, more preferably 5 nm or more, and preferably 100 nm or less, more preferably 30 nm or less.

<< transport layer (hole transport layer, electron transport layer) >>
The transport layer is a layer that transports carriers (holes and electrons). The transport layer is generally roughly divided into two. That is, the transport layer is roughly classified into a hole transport layer that transports holes (carriers) and an electron transport layer that transports electrons (carriers).

  The hole transport layer is a layer that transports (injects) holes supplied from the first electrode to the light emitting layer. The hole transport layer is provided between the first electrode or the hole injection layer and the light emitting layer. The hole transport layer also acts as a barrier that prevents the inflow of electrons from the second electrode side. Therefore, the term hole transport layer may be used in a broad sense to include a hole injection layer and / or an electron blocking layer. Note that only one hole transport layer may be provided or a plurality of layers may be provided.

  The electron transport layer is a layer that transports (injects) electrons supplied from the second electrode to the light emitting layer. The electron transport layer is provided between the second electrode or electron injection layer and the light emitting layer. The electron transport layer also acts as a barrier that prevents the inflow of holes from the first electrode side. Therefore, the term electron transport layer may be used in a broad sense to include an electron injection layer and / or a hole blocking layer. Note that only one electron transport layer or a plurality of electron transport layers may be provided.

  Electron transport material (hole blocking) used in the electron transport layer (when the electron transport layer has a single layer structure, the electron transport layer, and when multiple electron transport layers are provided, the electron transport layer located closest to the light emitting layer) There are no particular restrictions on the material that may also serve as a material. However, as the electronic material used for the electron transport layer, a material having a function of transmitting (transporting) electrons injected from the second electrode to the light emitting layer is usually applicable.

(Second electrode)
The second electrode (cathode) is an electrode film that supplies (injects) electrons to the light emitting layer. The material constituting the second electrode is not particularly limited, but is usually an electrode such as a material having a small work function (4 eV or less), for example, a metal (electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof. Formed of material.

  In the organic EL element, when light is extracted from the second electrode side, the second electrode can be formed of a light-transmitting electrode material, like the first electrode. In this case, for example, after forming a metal film made of an electrode material for forming a cathode so as to have a film thickness of 1 nm or more and 20 nm or less, a film made of a conductive transparent material described in the first electrode is formed on this metal film. Thus, a transparent or translucent second electrode can be formed.

(Extraction electrode)
The extraction electrode is an electrode for energizing (powering) the first electrode and the second electrode. The material constituting the extraction electrode is not particularly limited, but normally, the extraction electrode for the first electrode for energizing the first electrode energizes the second electrode with the same or the same material as the first electrode. Therefore, the extraction electrode for the second electrode is formed of the same or the same material as the second electrode.
The extraction electrode is not an essential configuration. For example, the extraction electrode for the first electrode may be formed integrally with the first electrode, and the extraction electrode for the second electrode is integrated with the second electrode. It may be formed.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "%" is used in an Example, unless otherwise indicated, "mass%" is represented.

≪Sample preparation≫
<Sample 1: Example>
A roll 11c on which a polyethylene terephthalate film (PET film: thickness 100 μm, width 700 mm) with a barrier film (SiOC: 80 nm) was wound was attached to the delivery chamber 201 of the vacuum line 200 in FIG. Then, an ITO film (130 nm) was formed in a pattern using a mask by sputtering in the first electrode forming chamber 206 on the film (base material) conveyed from the delivery chamber 201. The ITO film had a specific surface resistance of 30Ω / □.
In the organic functional layer forming chamber 208, α-NPD (40 nm), CBP (containing Ir (ppy) 3 as a co-deposition component: 6%: 35 nm), BAlq (5 nm), Alq 3 (40 nm), lithium fluoride ( 0.5 nm) was formed into a pattern by vapor deposition using a mask. Then, in the second electrode formation chamber 210, aluminum (110 nm) was formed into a pattern by vapor deposition using a mask. Then, in the laminating chamber 212, a PET film (80 μm) on which a gas barrier layer had been applied, on which 40 μm of sealing resin (adhesive) was applied, was laminated and wound around the roll 11e in the winding chamber 214. Then, in an air atmosphere, an organic EL element was cut out from the roll 11e to obtain a sample 1.
In Sample 1, as described above, ITO film deposition to sealing was performed in one vacuum line 200 (in one apparatus) in a vacuum atmosphere.

<Sample 2: Comparative Example>
A roll around which a polyethylene terephthalate film (PET film: thickness 100 μm, width 700 mm) with a barrier film (SiOC: 80 nm) was wound was attached in a vacuum chamber to form an anode. An ITO film (130 nm) was formed by sputtering. Then, on the surface where the ITO film is formed by taking it out into the atmosphere, a photolithographic resin that is polymerized with ultraviolet light is applied in a rectangular region with a width direction of 670 mm and a longitudinal direction of 720 mm, and then passed through a 90 ° C. drying oven. After alignment exposure, patterning was carried out through development, etching, and alkali treatment while being conveyed, washed with ultrapure water shower washing, sprayed with clean air, sufficiently dried, and then wound up. The ITO film had a specific surface resistance of 40Ω / □.
And the roll which wound up the film in which the ITO film | membrane was pattern-formed was attached to the delivery chamber 201 of FIG. 3 (Because the anode has already been formed, unlike the sample 1, the 1st electrode formation chamber 206 is attached. No film formation is performed. Thereafter, under the same conditions as Sample 1, in the organic functional layer forming chamber 208, the second electrode forming chamber 210, and the laminating chamber 212, pattern film formation and lamination were performed and wound on a roll. Then, an organic EL element was cut out from the roll 11e in an air atmosphere to obtain a sample 2.

<Sample 3: Comparative Example>
Unlike sample 2, sample 3 was subjected to scrub cleaning prior to cleaning with ultrapure water shower cleaning for the purpose of removing particles on the surface of the ITO film (electrode) after ITO film patterning. The scrub cleaning is a cleaning method in which a scrub roller in which a porous foam of urethane foam is disposed on a metal core is pressed against a film transported in an ultrapure water tank and cleaned.
Other manufacturing conditions were the same as those of Sample 2.

≪Sample evaluation≫
With respect to the produced samples 1 to 3, “light emission luminance unevenness” and “leakage current” were evaluated as follows.

<Light emission luminance unevenness tolerance value>
50 organic EL elements produced as described above were randomly selected for each sample. And 100 points | pieces were measured with respect to one organic EL element by CS-1000 (made by Konica Minolta Sensing) about the light-emission brightness | luminance when DC voltage 5V was applied. Next, the maximum value and the minimum value among 100 measured values of emission luminance of each organic EL element were obtained, and the emission luminance unevenness resistance value was calculated according to the following formula. And it evaluated by the minimum value (one with the largest variation) of the measured 50 light emission luminance unevenness tolerance values.
In addition, it can be judged that there is no variation in light emission luminance and there is no variation in light emission efficiency as the light emission luminance unevenness tolerance value is larger. In other words, it can be determined that “a decrease in luminance and light emission efficiency” can be prevented with a sample having a larger emission luminance unevenness tolerance value.

Light emission luminance unevenness tolerance value (%) = (light emission luminance minimum value / light emission luminance maximum value) × 100
And the evaluation criteria of the light emission luminance unevenness tolerance value are as follows.
○: Minimum value of light emission luminance unevenness resistance value is 90% or more Δ: Minimum value of light emission luminance unevenness resistance value is 80% or more and less than 90% ×: Minimum value of light emission luminance unevenness resistance value is less than 80%

<Leakage current>
50 organic EL elements produced as described above were randomly selected for each sample. Then, using a constant voltage power source, a reverse voltage (reverse bias) of 5 V was applied for 5 seconds, and the current flowing through the organic EL element was measured. And the largest value was made into the maximum electric current value among the measured 50 organic EL elements.
It can be determined that a sample having a smaller maximum current value can prevent “leak generation”.

Evaluation criteria for leakage current (maximum current value) are as follows.
○: Maximum current value is less than 1 × 10 ⁻⁵ A Δ: Maximum current value is 1 × 10 ⁻⁵ A or more, less than 1 × 10 ⁻³ A ×: Maximum current value is 1 × 10 ⁻³ A or more

<Examination of results>
As is apparent from the results shown in Table 1, since Sample 1 was manufactured by the method for manufacturing an organic EL element of the present invention, the evaluation values of emission luminance unevenness resistance and leakage current were both “◯”. It was found that “decrease in luminance and luminous efficiency” and “occurrence of leak” can be prevented.

  On the other hand, in the sample 2, since the ITO film was formed and patterned by another line (in another apparatus), the evaluation of the emission luminance unevenness resistance value was “Δ” and the leakage current was evaluated. Became “×”. In particular, it is determined that the cause of the poor evaluation of the leakage current is that particles adhere to the surface of the ITO film.

In sample 3, as in sample 2, the ITO film was formed and patterned in a separate line (in a separate device), and the evaluation of the emission luminance unevenness resistance value was “x”. The leakage current was evaluated as “Δ”.
Unlike the sample 2, the scrub cleaning can remove particles on the surface of the ITO film, so that the evaluation of the leakage current is slightly better than the sample 2. However, it was considered that the scrub cleaning caused damage to the ITO film, and as a result, the evaluation of the emission luminance unevenness resistance value was worse than that of Sample 2.

DESCRIPTION OF SYMBOLS 11 Substrate 200 Vacuum line 202 Cleaning / drying chamber 204 Extraction electrode formation chamber 206 First electrode formation chamber 208 Organic functional layer formation chamber 210 Second electrode formation chamber 212 Laminating chamber S1 Cleaning / drying step S2 Extraction electrode formation step S3 First electrode formation Process S4 Organic functional layer forming process S5 Second electrode forming process S6 Sealing process

Claims (3)

A first electrode forming step of forming a first electrode on a substrate;
An organic functional layer forming step of forming an organic functional layer including a light emitting layer so as to be laminated on the first electrode;
A second electrode forming step of forming a second electrode so as to be laminated on the organic functional layer;
-Containing Mutotomoni,
Extraction electrode forming step of forming at least one of an extraction electrode for energizing the first electrode and an extraction electrode for energizing the second electrode on the substrate before the first electrode formation step When,
Before the extraction electrode forming step, the substrate is dry-cleaned, and the substrate is dried until the moisture concentration is 500 ppm or less,
Further including
The process from the washing and drying step to the second electrode forming step is performed in a vacuum atmosphere by a roll-to-roll method. A sealing step of sealing what is formed on the substrate after the second electrode forming step;
2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the steps up to the sealing step are performed in a vacuum atmosphere by a roll-to-roll method. Wherein the first electrode and the extraction electrode is formed by sputtering, the method of manufacturing the organic electroluminescent device according to claim 1 or claim 2 using a mask during formation characterized in that it is patterned.

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