JP2006032683A - Organic el device and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain light emission with high efficiency and secure simplicity as well as stability in manufacturing process by improving electron impregnating property from a cathode into a light emitting layer in an organic EL element. <P>SOLUTION: The organic EL element is provided with at least the light emitting layer 60 between opposed anode 23 and cathode 50 while an organic compound containing indium (In) mixed thereinto is formed on the surface of the light emitting layer 60 as an electron impregnating layer 52. According to this constitution, electron impregnating property from the cathode into the light emitting layer can be improved without employing a low work function metal inactive in reaction. Therefore, the stability of element in the manufacturing process can be secured without necessitating inert atmosphere. Accordingly, the manufacturing process is simplified and a manufacturing cost can be reduced. On the other hand, a stabilized metal or In is employed whereby durability against oxygen or moisture is improved. Accordingly, the organic EL element can be obtained with the characteristic high in the light emitting efficiency and having stabilized characteristics. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an organic EL device, a method for manufacturing the organic EL device, and an electronic apparatus.

  In general, an organic EL element constituting an organic EL device has a structure in which an organic light-emitting material is formed as a thin film between an anode and a cathode. Then, electrons and holes injected from both electrodes are recombined in the light emitting layer, and the excited energy is emitted as light emission. Such an organic EL device has a problem of a charge injection barrier between each electrode and the light emitting layer. Tang et al. Used magnesium (Mg), which has a low work function, to lower the energy barrier, which is a problem when electrons are injected from the cathode (Appl. Phys. Lett., 51, 913 (1987). Literature 1)). At that time, since Mg is easily oxidized and unstable, it was used after being alloyed by co-evaporation with relatively stable silver (Ag). In addition, calcium (Ca) having a small work function is often used. In this case, a film such as aluminum (Al) is further formed as a protective layer.

  JP-A-2001-102175 (Patent Document 1) includes mixing a specific amount of a low work function metal such as lithium (Li) and an electron transporting organic compound by a co-evaporation technique to form an electron injection layer. It has been reported that even when aluminum (Al) is used for the cathode, it is driven at a low voltage.

However, even when an alloy electrode such as Mg is used, element degradation occurs due to oxidation of the electrode and the function as a wiring material must be taken into consideration, so that the alloy electrode is limited as an electrode material. In addition, low work function metals such as Ca and Li are highly reactive to oxygen and moisture, and are difficult to handle. Therefore, it becomes a factor which raises manufacturing cost, such as requiring an inert atmosphere in a manufacturing process. Further, these low work function metals are easily affected by oxygen and moisture taken in from inside or outside the device, and lower the stability of the device.
Appl. Phys. Lett., 51, 913 (1987). JP 2001-102175 A

The present invention has been made to solve the above problems, and provides an organic EL device capable of ensuring stability in a manufacturing process and obtaining high luminous efficiency, and a method for manufacturing the same. With the goal.
Another object is to provide an electronic device having good display characteristics.

In order to achieve the above object, an organic EL device of the present invention is an organic EL device having at least a light emitting layer between an anode and a cathode facing each other, and indium is provided between the light emitting layer and the cathode. An organic compound mixed with (In) is provided as an electron injection layer.
According to this configuration, the efficiency of electron injection from the cathode to the light emitting layer can be increased and the light emission efficiency can be improved without using a low work function metal. In addition, since In is a stable metal, handling in the manufacturing process is easy. Furthermore, since the durability against oxygen and moisture is high, the stability of the element can be improved.

The organic compound is preferably a nitrogen-containing heterocyclic compound and derivatives thereof, and more preferably a nitrogen-containing fused heterocyclic compound and derivatives thereof.
In particular, the organic compound is preferably a compound having a pyridine ring and a pyrazine ring or a phenanthroline skeleton and derivatives thereof.

  The organic compound is preferably tetra-2-pyridinylpyrazine and bathocuproine or bathophenanthroline.

On the other hand, an electronic apparatus according to the present invention includes the above-described organic EL device.
According to this configuration, an electronic device having good display characteristics can be provided.

  The present invention will be described in detail below. This embodiment shows a part of the present invention and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in each figure shown below, in order to make each layer and each member the size which can be recognized on drawing, the scale is varied for each layer and each member.

[Organic EL device]
First, an embodiment of the organic EL device of the present invention will be described.
(Equivalent circuit)
FIG. 1 is a schematic diagram showing a wiring structure of the organic EL device of the present embodiment. In FIG. 1, reference numeral 1 denotes the organic EL device. This organic EL device 1 is of an active matrix type using a thin film transistor (TFT) as a switching element, and has a plurality of scanning lines 101 and a plurality of signal lines 102 extending in a direction perpendicular to each scanning line 101. And a plurality of power supply lines 103 extending in parallel to each signal line 102, and a pixel region X is formed near each intersection of the scanning line 101 and the signal line 102. A data line driving circuit 100 including a shift register, a level shifter, a video line, and an analog switch is connected to the signal line 102. Further, a scanning line driving circuit 80 including a shift register and a level shifter is connected to the scanning line 101.

  Further, in each pixel region X, a switching TFT 112 to which a scanning signal is supplied to the gate electrode via the scanning line 101, and a storage capacitor for holding a pixel signal supplied from the signal line 102 via the switching TFT 112. 113, a driving TFT 123 to which a pixel signal held by the holding capacitor 113 is supplied to a gate electrode, and a driving current from the power supply line 103 when electrically connected to the power supply line 103 via the driving TFT 123 And a functional layer 110 sandwiched between the pixel electrode 23 and the common cathode (electrode) 50 are provided. The pixel electrode 23, the common cathode 50, and the functional layer 110 constitute a light emitting element, that is, an organic EL element.

  According to the organic EL device 1 having such a configuration, when the scanning line 101 is driven and the switching TFT 112 is turned on, the potential of the signal line 102 at that time is held in the holding capacitor 113, and The on / off state of the driving TFT 123 is determined according to the state. Then, a current flows from the power supply line 103 to the pixel electrode 23 through the channel of the driving TFT 123, and further a current flows to the common cathode 50 through the functional layer 110. Then, the functional layer 110 emits light according to the amount of current flowing therethrough.

(Plane configuration)
Next, specific modes of the organic EL device 1 of the present embodiment will be described with reference to FIGS. FIG. 2 is a plan view schematically showing the configuration of the organic EL device 1.

  As shown in FIG. 2, the organic EL device 1 according to the present embodiment includes a substrate 20 having optical transparency and electrical insulation, and a pixel electrode connected to a switching TFT (not shown) in a matrix on the substrate 20. A pixel electrode area (not shown) arranged in a shape, a power supply line arranged around the pixel electrode area and connected to each pixel electrode, and at least a substantially rectangular shape in plan view located on the pixel electrode area The pixel portion 3 (inside the one-dot chain line frame in FIG. 2) is provided. In the present embodiment, the pixel unit 3 includes an actual display area 4 (within the two-dot chain line in the figure) in the center and a dummy area 5 (one-dot chain line and two-dot chain line) arranged around the actual display area 4. Between the two areas).

In the actual display area 4, light emitting elements R, G, and B each having a pixel electrode are regularly arranged in the AB direction and the CD direction.
Further, scanning line driving circuits 80 and 80 are arranged on both sides of the actual display area 4 in FIG. The scanning line driving circuits 80 and 80 are provided on the lower layer side of the dummy region 5.

  Further, an inspection circuit 90 is disposed above the actual display area 4 in FIG. 2, and the inspection circuit 90 is disposed on the lower layer side of the dummy area 5. This inspection circuit 90 is a circuit for inspecting the operating state of the organic EL device 1 and includes, for example, inspection information output means (not shown) for outputting the inspection result to the outside, and is displayed during manufacture or at the time of shipment. It is configured to be able to inspect the quality and defects of the apparatus.

  The driving voltages of the scanning line driving circuit 80 and the inspection circuit 90 are applied from a predetermined power supply unit via the driving voltage conducting unit 310 (see FIG. 3) and the driving voltage conducting unit 340 (see FIG. 4). In addition, the drive control signal and the drive voltage to the scanning line drive circuit 80 and the inspection circuit 90 are supplied from a predetermined main driver that controls the operation of the organic EL device 1 and the drive control signal conduction unit 320 (see FIG. 3) and Transmission and application are performed via the drive voltage conduction unit 350 (see FIG. 4). The drive control signal in this case is a command signal from a main driver or the like related to control when the scanning line drive circuit 80 and the inspection circuit 90 output signals.

(Cross section configuration)
3 is a cross-sectional view taken along the line AB in FIG. 2, FIG. 4 is a cross-sectional view taken along the line CD in FIG. 2, and FIG. 5 is an enlarged cross-sectional view of the main part of FIG. As shown in FIGS. 3 and 4, the organic EL device 1 is formed by bonding a substrate 20 and a sealing substrate 30 through a sealing resin 40. In a region surrounded by the substrate 20, the sealing substrate 30, and the sealing resin 40, a getter agent 45 that absorbs moisture and oxygen is attached to the inner surface of the sealing substrate 30. The space is filled with nitrogen gas to form a nitrogen gas filled layer 46. Under such a configuration, moisture and oxygen are prevented from penetrating into the organic EL device 1, thereby extending the lifetime of the organic EL device 1.

In the case of a so-called top emission type organic EL device, the substrate 20 is configured to extract emitted light from the sealing substrate 30 side that is the opposite side of the substrate 20, so that both a transparent substrate and an opaque substrate can be used. it can. Examples of the opaque substrate include a thermosetting resin and a thermoplastic resin in addition to a ceramic sheet such as alumina and a metal sheet such as stainless steel that has been subjected to an insulation treatment such as surface oxidation.
In the case of a so-called bottom emission type organic EL device, since the emitted light is extracted from the substrate 20 side, a transparent or semi-transparent substrate 20 is employed. For example, glass, quartz, resin (plastic, plastic film) and the like can be mentioned, and a glass substrate is particularly preferably used. In the present embodiment, a bottom emission type in which emitted light is extracted from the substrate 20 side, and thus a transparent or translucent substrate 20 is used.

  As the sealing substrate 30, for example, a plate-like member having electrical insulation can be employed. Further, the sealing resin 40 is made of, for example, a thermosetting resin or an ultraviolet curable resin, and is preferably made of an epoxy resin which is a kind of thermosetting resin.

Further, as shown in FIG. 5, a circuit unit 11 including a driving TFT 123 for driving the pixel electrode 23 and the like is provided on the substrate 20. The circuit unit 11 is formed on the substrate 20. That is, a base protective layer 281 mainly composed of SiO ₂ is formed on the surface of the substrate 20 as a base, and a silicon layer 241 is formed thereon. A gate insulating layer 282 mainly composed of SiO ₂ and / or SiN is formed on the surface of the silicon layer 241.

In the silicon layer 241, a region overlapping with the gate electrode 242 with the gate insulating layer 282 interposed therebetween is a channel region 241a. The gate electrode 242 is a part of the scanning line 101 (not shown). On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surface of the gate insulating layer 282 that covers the silicon layer 241 and on which the gate electrode 242 is formed.

  Further, in the silicon layer 241, a low concentration source region 241b and a high concentration source region 241S are provided on the source side of the channel region 241a, while a low concentration drain region 241c and a high concentration drain are provided on the drain side of the channel region 241a. The region 241D is provided to form a so-called LDD (Light Doped Drain) structure. Among these, the high-concentration source region 241S is connected to the source electrode 243 through a contact hole 243a that opens over the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured as a part of the above-described power supply line 103 (see FIG. 1, extending in the direction perpendicular to the paper surface at the position of the source electrode 243 in FIG. 5). On the other hand, the high-concentration drain region 241D is connected to the drain electrode 244 made of the same layer as the source electrode 243 through a contact hole 244a that opens through the gate insulating layer 282 and the first interlayer insulating layer 283.

The upper layer of the first interlayer insulating layer 283 on which the source electrode 243 and the drain electrode 244 are formed is covered with a second interlayer insulating layer 284 mainly composed of, for example, an acrylic resin component. The second interlayer insulating layer 284 can be made of a material other than an acrylic insulating film, such as SiN or SiO ₂ . A pixel electrode 23 made of ITO is formed on the surface of the second interlayer insulating layer 284 and is connected to the drain electrode 244 through a contact hole 23a provided in the second interlayer insulating layer 284. Yes. That is, the pixel electrode 23 is connected to the high concentration drain region 241D of the silicon layer 241 through the drain electrode 244.
The layers from the substrate 20 to the second interlayer insulating layer 284 described above constitute the circuit unit 11.

  Note that TFTs (driving circuit TFTs) included in the scanning line driving circuit 80 and the inspection circuit 90 (see FIG. 2), that is, for example, an N-channel type that constitutes an inverter included in the shift register among these driving circuits or The P-channel TFT has the same structure as the driving TFT 123 except that it is not connected to the pixel electrode 23.

The surface of the second interlayer insulating layer 284 on which the pixel electrode 23 is formed is composed of the pixel electrode 23, a lyophilic control layer 25 mainly composed of a lyophilic material such as SiO ₂ , an acrylic resin, a polyimide resin, or the like. The organic partition wall layer 221 is covered. In addition, “lyophilic” of the lyophilic control layer 25 in the present embodiment means that the lyophilic property is higher than at least a material such as an acrylic resin or a polyimide resin constituting the organic partition layer 221. And The opening 25a provided in the lyophilic control layer 25 and the inside of the opening 221a provided in the organic partition layer 221 constitute a pixel region. Note that a BM (black matrix) (not shown) in which metallic chromium is formed by sputtering or the like is positioned between the organic partition wall layer 221 and the lyophilic control layer 25 at the boundary of each color display region (pixel region). Is formed.

(Light emitting element)
Light emitting elements (organic EL elements) R, G, and B are provided above the pixel electrode 23 in each pixel region. The light emitting elements R, G, and B include a pixel electrode 23 that functions as an anode, a hole injection layer 70 that injects / transports holes from the pixel electrode 23, and a light emitting layer 60 (60R, 60G made of an organic EL material). 60B) and the common cathode 50 are formed in order. In the light emitting elements R, G, and B having such a configuration, the holes injected from the hole injection layer 70 and the electrons transmitted from the common cathode 50 are combined in the light emitting layer 60. As a result, red, green or blue light is emitted.

  The pixel electrode 23 functioning as an anode is formed of a transparent conductive material because it is a bottom emission type in this example. ITO is suitable as the transparent conductive material, but other than this, for example, indium oxide / zinc oxide based amorphous transparent conductive film (Indium Zinc Oxide: IZO / registered trademark)) (Idemitsu Kosan) Etc.) can be used. In the present embodiment, ITO is used. In the case of the top emission type, it is not necessary to use a material having a light transmission property. For example, Al or the like may be provided on the lower layer side of ITO and used as a reflection layer.

As a material for forming the hole injection layer 70, in particular, a dispersion of 3,4-polyethylenediothiothiophene / polystyrene sulfonic acid (PEDOT / PSS) [trade name; Bytron-p: manufactured by Bayer], That is, a material obtained by dispersing 3,4-polyethylenedioxythiophene in polystyrenesulfonic acid as a dispersion medium and further dissolving it in a polar solvent such as water or isopropyl alcohol is preferably used. The material for forming the hole injection layer 70 is not limited to those described above, and various materials can be used. For example, a material obtained by dispersing polystyrene, polypyrrole, polyaniline, polyacetylene or a derivative thereof in an appropriate dispersion medium such as the aforementioned polystyrene sulfonic acid can be used.
Note that the pixel electrode 23 described above can also be configured by PEDOT / PSS. In this case, it becomes possible to form an anode having conductivity and hole injection by a single liquid phase process, and the formation of the hole injection layer can be omitted. Therefore, the manufacturing cost can be reduced.

  As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence is appropriately used. In the present embodiment, the emission wavelength bands are formed corresponding to the three primary colors of light in order to perform full color display. That is, one pixel is composed of three light emitting layers, a light emitting layer 60R corresponding to red, a light emitting layer 60G corresponding to green, and a light emitting layer 60B corresponding to blue. As a result, the organic EL device 1 performs full color display as a whole.

Although there is no limitation in particular as a formation material of the light emitting layer 60, For example, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinyl Polysilanes such as carbazole (PVK), polythiophene derivatives, and polymethylphenylsilane (PMPS) are preferably used. In addition, these polymer materials include polymer materials such as perylene dyes, coumarin dyes, rhodamine dyes, rubrene, perylene, 9,10-diphenylanthracene, tetraphenylbutadiene, Nile red, coumarin 6, and quinacridone. It can also be used by doping a low molecular weight material such as.
The “polymer” means a polymer having a molecular weight higher than that of a so-called “low molecule” having a molecular weight of about several hundreds. The above-mentioned polymer material includes a polymer generally called a polymer and having a molecular weight of 10,000 or more. In addition, a low polymer called an oligomer having a molecular weight of 10,000 or less is included.

  In this embodiment, MEHPPV (poly (3-methoxy 6- (3-ethylhexyl) paraphenylenevinylene) is used as a material for forming the red light emitting layer 60R, and polydioctylfluorene and F8BT are used as the material for forming the green light emitting layer 60R. Polydioctylfluorene is used as a material for forming the blue light-emitting layer 60R in the mixed solution of (dioctylfluorene and benzothiadiazole alternating copolymer). For example, the thickness of the blue light emitting layer 60B is preferably about 60 to 70 nm, although there is no limitation and the preferred thickness varies for each color.

(Electron injection layer)
In addition, an electron injection layer 52 is provided on the surface of the light emitting layer 60 and the organic partition wall layer 221. The electron injection layer 52 has a function of increasing the efficiency of electron injection from the cathode 50 to the light emitting layer 60. The thickness of the electron injection layer 52 is not particularly limited, but is preferably in the range of 10 to 500 mm. If it is less than 10 mm, the function as the electron injection layer is not sufficiently exhibited, and if it exceeds 500 mm, the drive voltage becomes so high that it cannot be ignored.

  Moreover, the organic compound which comprises an electron injection layer can employ | adopt the heterocyclic compound containing nitrogen, and those derivatives. Specifically, bathocuproin (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) and pasophenanthroline (4,7-diphenyl-1,10-phenanthroline) are desirably employed.

(cathode)
As shown in FIGS. 2 to 4, the common cathode 50 has an area larger than the total area of the actual display region 4 and the dummy region 5 and is formed so as to cover each.
The common cathode 50 is not particularly limited as long as it is a chemically stable conductive material, and an arbitrary material such as a metal or an alloy can be used. Specifically, Al (aluminum) is preferably used. . The thickness of the common cathode 50 is preferably about 100 nm to 500 nm, particularly about 200 nm. If the thickness is less than 100 nm, the protective function may not be sufficiently obtained. If the thickness exceeds 500 nm, the thermal load during production increases, and the light emitting layer 60 may be adversely affected such as deterioration or alteration. In the present embodiment, the cathode 50 is formed of Al. In particular, in the case of a top emission type organic EL device, it is possible to form a sufficiently thin auxiliary cathode 50 so as to have a light-transmitting property, or to provide a light-transmitting conductive material such as ITO. It is also possible to form the cathode 50 using a conductive material.

[Method for Manufacturing Organic EL Device]
Next, an example of a method for manufacturing the organic EL device 1 according to this embodiment will be described with reference to FIGS. Each cross-sectional view shown in FIGS. 6 and 7 corresponds to the cross-sectional view taken along the line AB in FIG. 2 and is shown in the order of each manufacturing process.
First, as shown in FIG. 6A, the pixel electrode 23 is formed on the surface of the circuit unit 11 on the substrate 20. Specifically, first, a conductive film made of a conductive material such as ITO is formed so as to cover the entire surface of the substrate 20. At that time, the contact hole 23a of the second interlayer insulating layer 284 is filled with a conductive material to form a contact. The pixel electrode 23 is formed by patterning this conductive film, and is electrically connected to the drain electrode 244 of the driving TFT 123 through a contact. At the same time, a dummy pattern 26 in the dummy area is also formed. 3 and 4, the pixel electrode 23 and the dummy pattern 26 are collectively referred to as the pixel electrode 23.

  The dummy pattern 26 is formed in an island shape like the pixel electrode 23 formed in the actual display area, but is not connected to the lower metal wiring via the second interlayer insulating layer 284. . Of course, the shape may be different from that of the pixel electrode 23 formed in the display area. In this case, the dummy pattern 26 includes at least the one located above the drive voltage conducting portion 310 (340).

  Next, as shown in FIG. 6B, a lyophilic control layer 25 that is an insulating layer is formed on the pixel electrode 23, the dummy pattern 26, and the second interlayer insulating layer 284. In the pixel electrode 23, the lyophilic control layer 25 is formed so as to partially open, and holes can be transferred from the pixel electrode 23 in the opening 25a (see also FIG. 3). Subsequently, in the lyophilic control layer 25, a BM (not shown) is formed in a concave portion formed between two different pixel electrodes 23. Specifically, a film is formed on the concave portion of the lyophilic control layer 25 by sputtering using metallic chromium.

Next, as shown in FIG. 6C, an organic partition layer 221 is formed so as to cover a predetermined position of the lyophilic control layer 25, specifically, the BM. As a specific method for forming the organic partition layer 221, for example, an organic layer is formed by applying a resist such as an acrylic resin or a polyimide resin dissolved in a solvent by various coating methods such as a spin coating method or a dip coating method. To do. The constituent material of the organic layer may be any material as long as it does not dissolve in the ink solvent described later and is easily patterned by etching or the like.
Subsequently, the organic layer is patterned using a photolithography technique and an etching technique, and a partition opening 221a is formed in the organic layer, thereby forming an organic partition layer 221 having a wall surface in the opening 221a. In this case, the organic partition layer 221 includes at least the one located above the drive control signal conducting unit 320.

  Next, a region showing lyophilicity and a region showing liquid repellency are formed on the surface of the organic partition layer 221. In the present embodiment, each region is formed by plasma processing. The plasma treatment includes a preliminary heating step, and an ink lyophilic step in which the upper surface of the organic partition layer 221 and the wall surface of the opening 221a, and the electrode surface 23c of the pixel electrode 23 and the upper surface of the lyophilic control layer 25 are made lyophilic. And an ink repellent process for making the upper surface of the organic partition wall layer and the wall surface of the opening liquid repellent, and a cooling process.

That is, the base material (the substrate 20 including the partition walls) is heated to a predetermined temperature, for example, about 70 to 80 ° C., and then plasma treatment using oxygen as a reaction gas at atmospheric pressure as an ink-philic process (O ₂ plasma treatment). I do. Next, as an ink repellent process, plasma treatment (CF ₄ plasma treatment) using methane tetrafluoride as a reaction gas under atmospheric pressure is performed, and then the substrate heated for the plasma treatment is cooled to room temperature. In addition, lyophilicity and liquid repellency are imparted to predetermined locations.

In this CF ₄ plasma treatment, the electrode surface 23c of the pixel electrode 23 and the lyophilic control layer 25 are somewhat affected, but the structure of the ITO that is the material of the pixel electrode 23 and the lyophilic control layer 25. Since materials such as SiO ₂ and TiO ₂ have poor affinity for fluorine, the hydroxyl group imparted in the ink-philic process is not replaced with the fluorine group, and the lyophilic property is maintained.

(Formation of hole injection layer)
Next, the hole injection layer 70 is formed by a hole injection layer formation step. In this hole injection layer forming step, an inkjet method is particularly preferably employed as the droplet discharge method. That is, by this ink jet method, the hole injection layer forming material is selectively disposed on the electrode surface 23c and applied. Thereafter, drying treatment and heat treatment are performed to form the hole injection layer 70 on the pixel electrode 23. As a material for forming the hole injection layer 70, for example, a material in which the PEDOT / PSS is dissolved in a polar solvent such as water or isopropyl alcohol is used.

  Here, in forming the hole injection layer 70 by the ink jet method, first, a hole injection layer forming material is filled in the ink jet head (not shown), and the ink jet head and the base material (substrate 20) are moved relative to each other. However, the discharge nozzle of the inkjet head is made to face the electrode surface 23c located in the opening 25a formed in the lyophilic control layer 25. Then, a droplet whose liquid amount per droplet is controlled is discharged from the discharge nozzle to the electrode surface 23c. Next, the discharged droplets are dried, and the hole injection layer 70 is formed by evaporating the dispersion medium and the solvent contained in the hole injection layer material.

At this time, the droplet discharged from the discharge nozzle spreads on the electrode surface 23c that has been subjected to the lyophilic treatment, and fills the opening 25a of the lyophilic control layer 25. On the other hand, droplets are repelled and do not adhere to the upper surface of the organic barrier layer 221 that has been subjected to ink repellent treatment. Therefore, even if the liquid droplet is displaced from a predetermined discharge position and a part of the liquid droplet is applied to the surface of the organic partition wall layer 221, the surface is not wetted by the liquid droplet, and the repelled liquid droplet is lyophilic. It is drawn into the opening 25 a of the property control layer 25.
In addition, after this hole injection layer formation process, it is preferable to carry out in inert gas atmospheres, such as nitrogen atmosphere and argon atmosphere, in order to prevent oxidation and moisture absorption of various formation materials and the formed element.

(Formation of light emitting layer)
Next, as shown in FIG. 7D, the light emitting layer 60 is formed by the light emitting layer forming step. In this light emitting layer forming step, an ink jet method, which is a droplet discharge method, is suitably employed as in the formation of the hole injection layer 70 described above. That is, the light emitting layer forming material is discharged onto the hole injection layer 70 by an ink jet method, and then a drying process and a heat treatment are performed, thereby forming the light emitting layer 60 in the opening 221a formed in the organic partition wall layer 221. To do. The light emitting layer 60 is formed for each color. Note that by using the ink jet method (droplet discharge method), the material for forming the light emitting layer 60 can be selectively disposed only at a predetermined position, that is, the pixel region, and the discharge amount can be set at each position. It is also possible to change. In the light emitting layer forming step, a nonpolar solvent that is insoluble in the hole injecting layer 70 is used as a solvent used for the light emitting layer forming material in order to prevent re-dissolution of the hole injecting layer 70. On the other hand, the firing temperature is preferably in the range of 150 ° C to 200 ° C. When the temperature is lower than 150 ° C., the forming material is not sufficiently cured. Therefore, when the forming material of the blue light emitting layer is provided thereon as described later, the forming materials may be mixed with each other. Further, if the temperature exceeds 200 ° C., the forming material may be deteriorated and deteriorated by heat.

(Formation of electron injection layer)
Next, as illustrated in FIG. 7E, the electron injection layer 52 is formed so as to cover the light emitting layer 60 and the organic partition wall layer 221. The electron injection layer 52 may be formed by any thin film forming method, for example, a vapor deposition method. In this case, In and an organic compound are co-evaporated under a vacuum of about 1 × 10 ⁻⁶ torr and deposited on the surfaces of the light emitting layer 60 and the organic barrier layer 221 to form the electron injection layer 52. In addition, when a thin film can be formed by coating from a solution, a coating method from a solution such as a spin coating method or an ink jet method can be used.

(Formation of cathode)
Next, the cathode 50 is formed. The cathode 50 is not limited as long as it is a conductive material that can be stably used in the air, but Al that is generally widely used as a wiring electrode is particularly preferable.

Thereafter, as shown in FIG. 7F, the surface of the substrate 20 is sealed with the sealing substrate 30. In this sealing step, the sealing substrate 30 with the getter agent 45 attached inside is bonded to the substrate 20 with the sealing resin 40. This sealing step is preferably performed in an inert gas atmosphere such as nitrogen, argon or helium. As a result, the inert gas is hermetically sealed in the space surrounded by the substrate 20, the sealing substrate 30, and the sealing resin 40.
Thus, the organic EL device 1 according to this embodiment is formed.

  As described above in detail, in the organic EL device and the manufacturing method thereof according to this embodiment, an organic compound in which In is mixed is formed as an electron injection layer. According to this configuration, the electron injectability from the cathode to the light emitting layer can be improved without using a reactive active low work function metal. Therefore, the stability of the element in the manufacturing process can be ensured without requiring an inert atmosphere. Therefore, the manufacturing process is simplified and the manufacturing cost can be reduced. Further, by using In which is a metal having low reactivity, durability of the element against oxygen and moisture is improved. Therefore, an organic EL device having high luminous efficiency and stable characteristics can be obtained.

[Electronics]
Next, the electronic device of the present invention will be described with reference to FIG. FIG. 8 is a perspective view of a mobile phone provided with the organic EL device of the present embodiment. In FIG. 8, reference numeral 1000 indicates a mobile phone body, and reference numeral 1001 indicates a display unit. Since the mobile phone 1000 includes the display unit 1001 including the organic EL device according to the present embodiment, it can exhibit good display characteristics.
In addition to such a mobile phone, the electronic device of the present embodiment can be applied to a portable information processing device such as a word processor or a personal computer, a wristwatch type electronic device, a flat panel display (for example, a television), or the like.

  In addition, this invention is not limited to the above-mentioned embodiment, It can implement in various deformation | transformation in the range which does not deviate from the meaning of this invention. For example, although the polymer material is used for the light emitting layer 60 in the above embodiment, a low molecular material can be used instead. Further, the configuration of the circuit unit 11 described above is only an example, and other configurations can be adopted.

An anode electrode made of ITO is formed on the upper surface of the glass substrate, a hole injection layer made of PEDOT / PSS is formed on the upper surface, and polydioctylfluorene and F8BT (alternate copolymer of dioctylfluorene and benzothiadiazole) on the upper surface. A light emitting layer was formed using a mixed solution of
An electron injection layer was formed on the top surface of the light emitting layer by simultaneously vacuum-depositing In and bathocuproine. For vacuum deposition, a vacuum deposition apparatus arranged in a glove box in a nitrogen atmosphere was used. The degree of vacuum at the start of deposition is about 4 × 10 −6 torr. The film formation rate was adjusted so that the molar ratio of In to bathocuproine was 1: 1, and a film was formed at 150 mm.
Al serving as a cathode was formed on the upper surface of the electron injection layer by vacuum evaporation of 2000 mm.
Thereafter, the whole was sealed with a sealing substrate.
In the organic EL device thus formed, a direct current voltage was applied between ITO serving as the anode electrode and Al serving as the cathode electrode, and the luminance of light emitted from the light emitting layer was measured. A circle plot in FIG. 9 shows luminance-voltage characteristics, and a circle plot in FIGS. 10 and 11 shows current efficiency-luminance characteristics.

(Comparative Example 1)
The layers up to the light emitting layer were formed in the same manner as in Example 1.
On the top surface of the light-emitting layer, 150 ml of bathocuproine was formed by vacuum deposition. Next, a film of Al was deposited by 2000 mm vacuum deposition.
Thereafter, the whole was sealed with a sealing substrate.
In the organic EL device thus formed, a direct current voltage was applied between ITO as the anode electrode and Al as the cathode electrode, and the luminance of light emitted from the light emitting layer was measured. The triangular plots in FIGS. 9 and 10 show the luminance-voltage characteristic and current efficiency-luminance characteristic, respectively. It was found that the device using the electron injection layer mixed with In in Example 1 had a lower driving voltage and higher efficiency.

(Comparative Example 2)
The layers up to the light emitting layer were formed in the same manner as in Example 1.
On the top surface of the light emitting layer, 200 cm of calcium (Ca) was formed by vacuum deposition. Next, a film of Al was deposited by 2000 mm vacuum deposition.
Thereafter, the whole was sealed with a sealing substrate.
In the organic EL device thus formed, a direct current voltage was applied between ITO serving as the anode electrode and Al serving as the cathode electrode, and the luminance of light emitted from the light emitting layer was measured. A square plot in FIG. 11 shows current efficiency-luminance characteristics. It was found that the device having the electron injection layer mixed with In in Example 1 was more efficient than the device using the Ca cathode.

It is a schematic diagram which shows the wiring structure of the organic electroluminescent apparatus of embodiment. It is a top view which shows typically the structure of the organic electroluminescent apparatus of embodiment. It is side surface sectional drawing which follows the AB line | wire of FIG. It is side surface sectional drawing which follows the CD line of FIG. It is a principal part expanded sectional view of FIG. It is sectional drawing explaining the manufacturing method of an organic electroluminescent apparatus in order of a process. It is sectional drawing explaining the manufacturing method of an organic electroluminescent apparatus in order of a process. It is a perspective view of a mobile phone provided with the organic EL device of the embodiment. It is a luminance-voltage characteristic in Example 1 and Comparative Example 1. It is a current efficiency-luminance characteristic in Example 1 and Comparative Example 1. It is a current efficiency-luminance characteristic in Example 1 and Comparative Example 2.

Explanation of symbols

  23 anode, 50 cathode, 52 electron injection layer, 60 light emitting layer.

Claims (10)

An organic EL device having at least a light emitting layer between an opposing anode and cathode,
An organic EL device comprising an organic compound mixed with indium (In) as an electron injection layer between the light emitting layer and the cathode.   The organic EL device according to claim 1, wherein the organic compound is a heterocyclic compound containing nitrogen and a derivative thereof.   3. The organic EL device according to claim 1, wherein the organic compound is a condensed heterocyclic compound containing nitrogen and a derivative thereof.   The organic EL device according to any one of claims 1 to 3, wherein the organic compound is a compound having a pyridine ring and a derivative thereof.   The organic EL device according to any one of claims 1 to 4, wherein the organic compound is a compound having a pyrazine ring and a derivative thereof.   The organic EL device according to any one of claims 1 to 5, wherein the organic compound is a compound having a phenanthroline skeleton and a derivative thereof.   The organic EL device according to any one of claims 1 to 6, wherein the organic compound is tetra-2-pyridinylpyrazine.   The organic EL device according to claim 1, wherein the organic compound is bathocuproine.   The organic EL device according to any one of claims 1 to 6, wherein the organic compound is bathophenanthroline.   An electronic apparatus comprising the organic EL device according to claim 1.

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