JP4730133B2 - Organic EL device and electronic device - Google Patents

Description

  The present invention relates to an organic EL device and an electronic apparatus.

An organic EL device in which organic EL elements are arranged and arranged has been developed. The organic EL device includes an organic light emitting layer between an anode and a cathode. In this organic EL device, holes supplied from the anode and electrons supplied from the cathode are recombined in the light emitting layer to emit light. In order to improve the efficiency of hole injection from the anode to the light emitting layer, a hole injection layer is often formed between the anode and the light emitting layer.
JP 2004-111904 A

  The biggest problem of the organic EL device is luminance deterioration during driving. In order to suppress this luminance degradation, development of light emitting materials and carrier transport layers, development of electrodes that improve carrier injection efficiency, and development of sealing technology that suppresses the entry of moisture and oxygen that generate dark spots have been promoted. Yes. As one of the developments, Patent Document 1 proposes a technique for improving light emission characteristics in a light emitting layer by adopting a material containing a metal element constituting an electrode as a material for forming a hole transport layer. Yes. However, the organic EL device is required to further improve the light emission lifetime due to luminance deterioration.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an organic EL device capable of improving the light emission lifetime.

In order to achieve the above object, an organic EL device according to the present invention includes a cathode, an anode containing a metal element, and an anode disposed between the anode and the cathode, and the coating film of PEDOT / PSS is dried. An organic EL device comprising a hole injection layer formed and an organic film disposed adjacent to the hole injection layer between the anode and the cathode, wherein the organic film is a light emitting layer The hole injection layer contains 1.0 atm% or more of the metal element diffused from the anode, and extends from the interface between the hole injection layer and the organic film to 20 nm inside the organic film. The region includes 0.2 atm% or more of the metal element diffused from the anode.
In addition, it is preferable that at least one of the organic films includes 1.0 atomic% or more of the metal element.
It is considered that the emission lifetime of the organic EL device is reduced by diffusing negative ion components such as sulfate ions and sulfonate ions existing in the hole injection layer into other organic films.
On the other hand, if the said structure is employ | adopted, it will become possible to suppress that the negative ion component of a positive hole injection layer migrates to another organic film with the positive ion component of a metal element. Therefore, the light emission lifetime of the organic EL device can be improved.

The metal element is contained in a plurality of the organic films including the hole injection layer among the organic films from the hole injection layer to the light emitting layer disposed adjacent to the anode in the pair of conductive films. It is desirable.
According to this configuration, the negative ion component that migrates from the hole injection layer to the other organic film can be suppressed by the positive ion component of the metal element. Therefore, the light emission lifetime of the organic EL device can be improved.

The hole injection layer is preferably made of an organic material that exhibits acidity due to moisture absorption.
According to this configuration, since the anode is dissolved by the moisture absorption of the hole injection layer, the metal element contained in the anode can be diffused from the hole injection layer to the light emitting layer.

The hole injection layer is preferably formed by drying a coating film of PEDOT / PSS.
According to this configuration, it is possible to easily form a hole injection layer that exhibits acidity due to moisture absorption.

The metal element contained in the plurality of organic films is preferably the same metal element as the metal element contained in the anode.
According to this configuration, the physical properties and the like contained in the plurality of organic films are close to those of the anode, so that holes can be transported quickly and efficiently. Therefore, the light emission characteristics in the light emitting layer are improved.

The hole injection layer contains the metal element in an amount of 1.0 atm% or more, and a part of the organic film disposed adjacent to the hole injection layer contains the metal element in an amount of 0.2 atm% or more. It is desirable that Here, a part of the organic film refers to a region from the interface between the hole injection layer and the organic film to about 20 nm inside the organic film.
According to this configuration, the negative ion component that migrates from the hole injection layer to the other organic film can be suppressed by the positive ion component of the metal element. Therefore, the light emission lifetime of the organic EL device can be improved.

On the other hand, an electronic apparatus according to the present invention includes the above-described organic EL device in a display unit.
According to this configuration, since the organic EL device capable of improving the light emission lifetime is provided, an electronic device having excellent reliability can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing referred to below, the dimensions and the like of each component are appropriately changed and displayed for easy understanding.

(First embodiment)
First, the organic EL device according to the first embodiment of the present invention will be described.
FIG. 1 is a side sectional view of the organic EL device according to the first embodiment. In the organic EL device according to the first embodiment, the hole injection layer 70 and the light emitting layer 60 contain a metal element.

  In general, the organic EL device includes an element substrate 2, a drive circuit unit 5 disposed on the surface of the element substrate 2, a plurality of organic EL elements 3 disposed on the surface of the drive circuit unit 5, and the organic EL element 3 The sealing substrate 30 is mainly configured. The organic EL elements 3 are formed in a circular shape, an oval shape, or the like when viewed from a direction perpendicular to the element substrate 2, and are arranged in a matrix on the element substrate 2. In the present embodiment, a bottom emission type organic EL device that takes out light emitted from the organic EL element 3 from the element substrate 2 side will be described as an example.

(Organic EL device)
In the bottom emission type organic EL device, since light emitted from the light emitting layer 60 is extracted from the element substrate 2 side, a transparent or translucent element substrate 2 is employed. For example, glass, quartz, resin (plastic, plastic film) or the like can be used, and a glass substrate is particularly preferably used.

  On the element substrate 2, a drive circuit unit 5 including a drive TFT 123 (drive element 4) of the organic EL element 3 is formed. Note that an organic EL device can be configured by mounting an IC chip having a drive circuit on the element substrate 2.

As a specific configuration of the drive circuit unit 5, a base protective layer 281 made of an insulating material is formed on the surface of the element substrate 2, and a silicon layer 241 that is a semiconductor material 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. A gate electrode 242 is formed on the surface of the gate insulating layer 282. The gate electrode 242 is constituted by a part of a scanning line (not shown). Of the silicon layer 241, a region facing the gate electrode 242 with the gate insulating layer 282 interposed therebetween is a channel region 241a. On the other hand, a first interlayer insulating layer 283 mainly composed of SiO ₂ is formed on the surfaces of the gate electrode 242 and the gate insulating layer 282.

  Further, in the silicon layer 241, a low concentration source region 241b and a high concentration source region 241S are provided on one side of the channel region 241a, and a low concentration drain region 241c and a high concentration drain region 241D are provided on the other side of the channel region 241a. A so-called LDD (Lightly Doped Drain) structure is provided. Among these, the high-concentration source region 241S is connected to the source electrode 243 through a contact hole 243a penetrating the gate insulating layer 282 and the first interlayer insulating layer 283. The source electrode 243 is configured by a part of a power supply line (not shown). On the other hand, the high concentration drain region 241D is connected to a drain electrode 244 disposed in the same layer as the source electrode 243 through a contact hole 244a that penetrates the gate insulating layer 282 and the first interlayer insulating layer 283.

  Over the source electrode 243 and the drain electrode 244 and the first interlayer insulating layer 283 described above, a planarizing film 284 mainly composed of a heat-resistant insulating resin material such as acrylic or polyimide is formed. The planarizing film 284 is formed to eliminate surface irregularities due to the driving TFT 123 (driving element 4), the source electrode 243, the drain electrode 244, and the like.

  A plurality of pixel electrodes 23 are arranged in the formation region of the organic EL element 3 on the surface of the planarizing film 284. The pixel electrode 23 is connected to the drain electrode 244 through a contact hole 23 a provided in the planarizing film 284. 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.

In addition, an inorganic partition wall 25 made of an inorganic insulating material such as SiO ₂ is formed so as to surround the pixel electrode 23 on the surface of the planarizing film 284. A plurality of functional films are laminated on the surface of the pixel electrode 23 exposed from the opening of the inorganic partition wall 25 to constitute the organic EL element 3. The organic EL element 3 functions as a pixel electrode 23 that functions as an anode, a hole injection layer 70 that injects / transports holes from the pixel electrode 23, a light emitting layer 60 that includes an organic EL material, and a cathode 52. The common electrode is laminated.

In the case of a bottom emission type organic EL device, the pixel electrode 23 that functions as an anode is formed of a transparent conductive material. As the transparent conductive material, ITO (indium tin oxide), IZO (registered trademark, indium zinc oxide), or the like can be used. Among them, ITO is composed of a material in which indium oxide (In ₂ O ₃ ) is doped with tin (Sn).

As the material for forming the hole injection layer 70, a material that exhibits acidity (preferably PH4 or less) by moisture absorption is employed. In particular, a dispersion of 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS) is preferably used. This PEDOT / PSS is obtained by dispersing 3,4-polyethylenedioxythiophene, which is a polythiophene derivative, in polystyrene sulfonic acid as a dispersion medium and further dispersing it in water.
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.

  As a material for forming the light emitting layer 60, a known light emitting material capable of emitting fluorescence or phosphorescence is used. Specifically, (poly) fluorene derivative (PF), (poly) paraphenylene vinylene derivative (PPV), polyphenylene derivative (PP), polyparaphenylene derivative (PPP), polyvinylcarbazole (PVK), polythiophene derivative, polymethyl Polysilanes such as phenylsilane (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.

  Further, as a material for forming the red organic EL layer 60, for example, MEHPPV (poly (3-methoxy6- (3-ethylhexyl) paraphenylenevinylene) is used, and as a material for forming the green organic EL layer 60, for example, polydioctylfluorene is used. For example, polydioctylfluorene may be used as a material for forming the blue organic EL layer 60 in the mixed solution of F8BT (an alternating copolymer of dioctylfluorene and benzothiadiazole). In particular, the thickness is not limited, and a preferable film thickness is adjusted for each color.

  The cathode 52 preferably has a laminated structure of a main cathode and an auxiliary cathode. As the main cathode, it is desirable to employ a material such as Ca, Mg, LiF having a work function of 3.0 eV or less. Thereby, since the function as an electron injection layer is provided to the main cathode, the light emitting layer can emit light at a low voltage. The auxiliary cathode has functions of enhancing the conductivity of the entire cathode 52 and protecting the main cathode from oxygen, moisture, and the like. Therefore, it is desirable to employ a metal material such as Al, Au, or Ag having excellent conductivity as the auxiliary cathode.

On the other hand, the sealing substrate 30 is bonded to the upper side of the cathode 52 through the adhesive layer 40. A sealing cap that covers the entire cathode 52 may be fixed to the periphery of the element substrate 2, and a getter agent that absorbs moisture, oxygen, or the like may be disposed inside the sealing cap. Further, an inorganic sealing film made of SiO ₂ or the like may be laminated on the surface of the cathode 52.

  In the organic EL device described above, the image signal supplied from the source electrode 243 of the drive circuit unit 5 is applied to the pixel electrode 23 by the drive element 4 at a predetermined timing. Then, the holes injected from the pixel electrode 23 and the electrons injected from the cathode 52 are recombined in the light emitting layer 60 and light having a predetermined wavelength is emitted. The emitted light passes through the pixel electrode 23 made of a transparent material, the drive circuit unit 5 and the element substrate 2 and is extracted outside. Since the inorganic partition wall 25 is made of an insulating material, a current flows only inside the opening of the inorganic partition wall 25 and the light emitting layer 60 emits light. Therefore, the inside of the opening of the inorganic partition wall 25 is a pixel region of the organic EL element 3.

(Metal element)
FIG. 2A is a schematic cross-sectional view of the organic EL element according to this embodiment. The pixel electrode 23 of the organic EL element is made of a material containing a metal element. That is, since the pixel electrode 23 is made of ITO (indium tin oxide; In ₂ O ₃ doped with Sn or the like), the pixel electrode 23 contains a metal element such as In or Sn.

  On the other hand, among the organic films from the hole injection layer 70 adjacent to the pixel electrode 23 to the light emitting layer 60, a plurality of organic films including the hole injection layer 70 contain a metal element. In the first embodiment, a part of the hole injection layer 70 and the light emitting layer 60 contains a metal element. Here, a part of the light emitting layer 60 refers to a region from the interface between the hole injection layer 70 and the light emitting layer 60 to the inside of the light emitting layer 60 of about 20 nm. As this metal element, the same kind of metal element as the metal element contained in the pixel electrode 23 is contained. That is, in the hole injection layer 70 and the light emitting layer 60, metal elements such as In and Sn are present in an ion state.

Thus, it has been confirmed that light emission (so-called light emission blur) outside the pixel region of the organic EL element can be suppressed by diffusing the metal element of the pixel electrode 23 into the hole injection layer or the like. This is presumed to be due to the following reason.
FIG. 2B is a chemical formula of polystyrene sulfonic acid (PSS) contained in the hole injection layer. Polystyrene sulfonic acid is negatively charged due to the presence of a sulfonic group (—SO ₃ —) and exhibits a function as a dopant for 3,4-polyethylenedioxythiophene, which is a polythiophene derivative. As shown in FIG. 2A, positive ions of metal elements such as In + and Sn + are present in the hole injection layer containing PSS- in this embodiment. Thereby, the hole injection layer 70 is electrically neutralized, the function as a dopant of polystyrene sulfonic acid is lowered, and the electrical resistance is considered to be increased. Therefore, the possibility that holes supplied from the pixel electrode 23 spread beyond the pixel region is reduced, and light emission outside the pixel region can be suppressed.

In addition, it has been confirmed that the lifetime of the organic EL element can be improved by diffusing the metal element of the pixel electrode into the hole injection layer or the like. The mechanism is not clear, but is presumed to be due to the following reasons.
In the polystyrene sulfonic acid shown in FIG. 2B, a sulfonic group (—SO ₃ —) may be liberated. The released sulfone group penetrates into the light emitting layer 60 from the hole injection layer 70 shown in FIG. 2A (migration). As a result, it is considered that the luminous efficiency, carrier balance, and the like of the light emitting layer 60 made of an organic material are changed to cause luminance deterioration and the light emission lifetime is shortened. On the other hand, in this embodiment, positive ions of metal elements such as In + and Sn + are also present in a part of the light emitting layer 60. This positive ion suppresses migration of sulfone-based negative ions that try to enter the light emitting layer 60. Therefore, it is possible to suppress the luminance deterioration of the light emitting layer 60 and to improve the light emission lifetime.

(Method for manufacturing organic EL device)
Next, a method for manufacturing the organic EL device according to this embodiment will be described.
3 and 4 are process diagrams of the method for manufacturing the organic EL device according to the first embodiment. In FIGS. 3 and 4, for ease of understanding, description of the element substrate, the drive circuit portion, and the sealing substrate is omitted, and an enlarged view of portion A in FIG. 1 is shown.
First, as shown in FIG. 3A, an inorganic partition wall 25 is formed around the pixel electrode 23. Next, ultrasonic cleaning of the substrate surface is performed using ultrapure water. Further, as the lyophilic process on the surface of the pixel electrode 23, an atmospheric pressure plasma process using oxygen gas or the like is performed.

  Next, as shown in FIG. 3B, a hole injection layer 70 is formed on the entire surface of the pixel electrode 23 and the inorganic partition wall 25 by a liquid phase process. Specifically, first, a liquid material for forming the hole injection layer 70 is applied to the entire substrate by spin coating, spray coating, dipping, or the like. Next, the coating film is heated and dried to remove moisture contained in the film. For example, heat treatment is performed at 180 ° C. for 15 minutes in the atmosphere.

Next, as shown in FIG. 3C, the hole injection layer 70 is left in an atmosphere in which at least one of moisture and oxygen is present. This leaving step is performed in the air conditioning room 10 in which the water concentration and / or the oxygen concentration can be adjusted.
The air conditioning room 10 includes a chamber 11 in which a substrate can be disposed, a moisture supply device 12 and an oxygen supply device 13 into the chamber 11, and an exhaust device 14 in the chamber 11. With the moisture supply device 12 and the oxygen supply device 13, the moisture concentration and the oxygen concentration in the chamber 11 can be adjusted in the range of 10% or more and 100% or less, respectively. Thereby, the inside of the chamber 11 can be maintained in an atmosphere in which at least one of moisture and oxygen is present.

  A substrate on which the hole injection layer 70 is formed is placed in the chamber 11 of the air conditioning room 10. Next, the inside of the chamber 11 is adjusted to the same atmosphere as the atmosphere (moisture concentration of 45% or less, oxygen concentration of about 21%), and the hole injection layer 70 is exposed to the atmosphere. As will be described later, the exposure time is desirably 6 hours or more. As a result, the hole injection layer 70 absorbs moisture and becomes acidic. The pixel electrode 23 is dissolved by the hole injection layer 70, and the metal element contained in the pixel electrode 23 diffuses into the hole injection layer 70.

Next, as shown in FIG. 4A, a light emitting layer 60 is formed on the surface of the hole injection layer 70 by a liquid phase process. Specifically, the liquid material for forming the light emitting layer 60 is applied to the entire substrate by spin coating, spray coating, dipping, or the like.
Next, as shown in FIG. 4B, the light emitting layer 60 is dried. This drying step is performed inside the N ₂ glove box 15. The N ₂ glove box 15 includes a chamber 16 in which a substrate can be disposed, an N ₂ gas supply device 17 into the chamber 16, an exhaust device 18 in the chamber 16, and a substrate heating device 19. Yes. The N ₂ gas supply device 17 can replace the air in the chamber with N ₂ gas.

In the chamber 16 of the N ₂ glove box 15, a substrate coated with a light emitting layer forming material is disposed. Next, the inside of the chamber 16 is replaced with N ₂ gas, and the concentration of moisture and oxygen in the chamber 16 is reduced to 1 ppm or less. Next, the substrate is heated by the heating device 19 to dry the coating film. For example, heat treatment is performed at 160 ° C. for 30 minutes. Thereby, the light emitting layer 60 is formed.
As described above, the metal element constituting the pixel electrode 23 is diffused inside the hole injection layer 70. The metal element diffuses from the hole injection layer 70 to a part of the light emitting layer 60 in accordance with the heat treatment of the light emitting layer 60.

Next, as shown in FIG. 4C, the cathode 52 is formed by a vacuum deposition method or the like.
Thus, the organic EL device according to the first embodiment is formed.

  FIG. 5 is an explanatory diagram for comparison between the organic EL device according to the first embodiment (Example 1) and the organic EL device according to the related art (Comparative Example 1). FIG. 5A is a table describing the concentration of the metal element in each layer, and FIG. 5B is a graph showing the luminance deterioration of the organic EL device.

  As shown in FIG. 5A, in the organic EL device according to Example 1, the concentration of the metal element in the hole injection layer is 2.4 atm%, and the concentration of the metal element in a part of the light emitting layer is 0. 2 atm%. The part of the light emitting layer refers to a region from the interface between the hole injection layer and the light emitting layer to the inside of the light emitting layer of about 20 nm. Incidentally, when the time during which the hole injection layer is exposed to an atmosphere containing at least one of moisture and oxygen (hereinafter referred to as “exposure time”) is 6 hours, the concentration of the metal element in the hole injection layer is 1. 0 atm% or more. When the exposure time is 24 hours, the concentration of the metal element in the hole injection layer is about 2.4 atm%, and the concentration of the metal element at the interface between the light emitting layer and the hole injection layer is about 0.3 atm%. is there.

  On the other hand, in the organic EL device according to Comparative Example 1, the metal element is contained only in the hole injection layer. That is, the concentration of the metal element in the hole injection layer is 0.5 atm%, but the light emitting layer contains no metal element.

  Luminous efficiency was measured for the organic EL devices according to Example 1 and Comparative Example 1. The luminous efficiency is indicated by a current value necessary for obtaining the same luminance. In Comparative Example 1, in order to obtain the same luminance as that of Example 1, a current about 1.17 times that of Example 1 was required. Thereby, it was confirmed that the luminous efficiency of Example 1 was superior to Comparative Example 1.

  Further, with respect to the organic EL devices according to Example 1 and Comparative Example 1, the change in emission luminance with time was measured. As a result, as shown in FIG. 5B, it was found that the rate of decrease in light emission luminance in Example 1 was slower than that in Comparative Example 1. It was confirmed that when the 10% decrease in emission luminance was defined as the lifetime, the emission lifetime of the organic EL device according to Example 1 was increased to about 1.5 times that of Comparative Example 1.

  As described in detail above, the organic EL device according to the first embodiment has a configuration in which a metal element is contained in the hole injection layer and the light emitting layer. According to this configuration, the negative ion component that is to diffuse from the hole injection layer to the light emitting layer can be captured by the positive ions of the metal element. Therefore, the light emission lifetime of the organic EL device can be improved, and the light emission efficiency can be improved.

  Further, in the method for manufacturing the organic EL device according to the first embodiment, a step of forming a hole injection layer made of an organic material that exhibits acidity by moisture absorption on the surface of the pixel electrode containing a metal element, and at least moisture or oxygen And a step of exposing the hole injection layer to an atmosphere where one exists. According to this configuration, since the hole injection layer absorbs moisture and exhibits acidity, the lower pixel electrode is dissolved, and the metal element contained in the anode diffuses into the hole injection layer. In addition, since the light emitting layer is subjected to heat treatment, the metal element of the pixel electrode can be diffused from the hole injection layer to a part of the light emitting layer. As a result, the light emission lifetime can be improved and the light emission efficiency can be improved.

  Further, in the method for manufacturing the organic EL device according to the first embodiment, it is possible to form the hole injection layer and the light emitting layer using the same material as in the conventional technique. That is, since it is not necessary to add a metal element in advance to the liquid that is a material for forming the hole injection layer, the film formability of the hole injection layer can be improved. Further, the dispersibility of the metal element in the hole injection layer can be improved.

(Second Embodiment)
Next, an organic EL device according to a second embodiment of the present invention will be described.
FIG. 7 is a side sectional view of the organic EL device according to the second embodiment. In the organic EL device according to the second embodiment, a hole transport layer 65 is formed between the hole injection layer 70 and the light emitting layer 60, and the hole injection layer 70 and the hole transport layer 65 contain a metal element. This is different from the first embodiment. Note that detailed description of portions having the same configuration as in the first embodiment is omitted.

  In the organic EL device according to the second embodiment, the hole transport layer 65 is formed on the entire surface of the hole injection layer 70. As a constituent material of the hole transport layer 65, TFB (poly (2,7- (9,9-di-n-octylfluorene) -alt- (1,4-phenylene-((4-sec It is desirable to employ -butylphenyl) imino-1,4-phenylene)))). TFB is a polymer compound in which TPD is incorporated into the main chain or side chain, and is formed between the hole injection layer 70 and the light emitting layer 60 and assists in transporting holes from the hole injection layer 70 to the light emitting layer 60. It is suitable because of its role. In addition, the thickness of the hole transport layer 65 is formed to 20 nm or less.

  Next, a method for manufacturing an organic EL device according to the second embodiment will be described. First, as in the first embodiment, the hole injection layer 70 is formed on the surface of the pixel electrode 23 and the inorganic partition wall 25 by performing the steps shown in FIGS. 3A to 3C. In the hole injection layer 70, the metal element of the pixel electrode 23 is diffused.

FIG. 8 is a process diagram of a method for manufacturing an organic EL device according to the second embodiment.
As shown in FIG. 8A, a hole transport layer 65 is formed on the surface of the hole injection layer 70 by a liquid phase process. Specifically, a TFB liquid material which is a hole transport layer is applied to the entire substrate by spin coating, spray coating, dipping, or the like.

Next, as shown in FIG. 8B, the hole transport layer 65 is dried. This drying step is performed inside the N ₂ glove box 15. Specifically, a substrate coated with a material for forming the hole transport layer 65 is disposed in the chamber of the N ₂ glove box 15. Next, the inside of the chamber is replaced with N 2 gas, and the concentration of moisture and oxygen in the chamber is reduced to 1 ppm or less. Next, the substrate is heated at 180 ° C. for 1 hour to dry the coating film, and the hole transport layer 65 is formed. Thereafter, it is desirable to remove the soluble layer of TFB with a xylene solvent. Thereby, a TFB layer insoluble in the xylene solvent is formed.

Thereafter, similarly to the first embodiment, the steps shown in FIGS. 4A to 4C are performed to form the light emitting layer 60 and the cathode 52.
Thus, the organic EL device according to the second embodiment is formed.

  FIG. 9 is an explanatory diagram for comparison between the organic EL device according to the second embodiment (Example 2) and the organic EL device according to the related art (Comparative Example 2). FIG. 9A is a table showing the concentration of the metal element in each layer, and FIG. 9B is a graph showing the luminance deterioration of the organic EL device.

  As shown in FIG. 9A, in the organic EL device according to Example 2, the concentration of the metal element in the hole injection layer is 1.0 atm% or more, and the concentration of the metal element in the hole transport layer is 0. 0. 2 atm% or more. In contrast, in the organic EL device according to Comparative Example 2, the metal element is contained only in the hole injection layer. That is, the concentration of the metal element in the hole injection layer is 0.5 atm%, but the hole transport layer contains no metal element.

Luminous efficiency was measured for the organic EL devices according to Example 2 and Comparative Example 2. In Comparative Example 2, in order to obtain the same luminance as in Example 2, a current approximately 1.06 times that in Example 2 was required. Thereby, it was confirmed that the luminous efficiency of Example 2 was superior to that of Comparative Example 2.
In addition, with respect to the organic EL devices according to Example 2 and Comparative Example 2, the change in emission luminance with time was measured. As a result, as shown in FIG. 9B, it was found that the rate of decrease in emission luminance in Example 2 was slower than the rate of decrease in emission luminance in Comparative Example 2. Thereby, it was confirmed that the light emission lifetime of the organic EL device according to Example 2 was longer than that of Comparative Example 2.

  FIG. 6 is a graph showing the relationship between the time during which the hole injection layer is left in the atmosphere (exposure) and the emission lifetime of the organic EL element. The inventor of the present application made various prototypes of organic EL devices by changing the time in which the hole injection layer was left in the atmosphere. The moisture concentration in the atmosphere is 45% or less, and the oxygen concentration is about 21%. And the light emission lifetime of each organic EL apparatus was measured. In FIG. 6, the light emission lifetime when the hole injection layer is left in the atmosphere for 24 hours is normalized as 1. As shown in FIG. 6, the emission lifetime when the hole injection layer is left in the atmosphere for 0.5 hours is as low as about 0.7, but the emission lifetime when left in the atmosphere for 6 hours or more is 0.9 to 1.1. It has converged to the extent of the degree. From this result, it can be said that the leaving time of the hole injection layer is desirably 6 hours or more.

  As described in detail above, the organic EL device according to the second embodiment has a configuration in which a metal element is contained in the hole injection layer and the hole transport layer. According to this configuration, it is possible to capture the negative ion component that is to diffuse from the hole injection layer through the hole transport layer into the light emitting layer by the positive ion component of the metal element. Therefore, the light emission lifetime of the organic EL device can be improved, and the light emission efficiency can be improved.

  Moreover, in the manufacturing method of the organic EL device according to the second embodiment, since the hole transport layer is formed while being heated, the metal element of the pixel electrode is added to the hole injection layer and also to the hole transport layer. Can be diffused. As a result, the light emission lifetime can be improved and the light emission efficiency can be improved. In addition, the hole transport layer can be formed using the same material as the conventional one.

(Electronics)
Next, an electronic apparatus including the organic EL device according to the embodiment will be described with reference to FIG.
FIG. 10 is a perspective configuration diagram of a mobile phone which is an example of an electronic apparatus. A cellular phone 1300 shown in the figure includes a plurality of operation buttons 1302, an earpiece 1303, a mouthpiece 1304, and a display unit 1301 including the organic EL device of the previous embodiment. The display unit employs the organic EL device of the above embodiment. In the organic EL device of the above embodiment, since the light emission lifetime can be improved, a mobile phone with excellent reliability can be provided.

  Note that the electronic device including the light emitting device according to the present invention is not limited to the above-described ones. For example, a digital camera, a personal computer, a television, a portable television, a viewfinder type / monitor direct view type video tape recorder, Examples include a PDA, a portable game machine, a pager, an electronic notebook, a calculator, a clock, a word processor, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel. In addition, examples of the electronic device including the organic EL device according to the present invention include an in-vehicle audio device, an in-vehicle instrument, an in-vehicle display such as a car navigation device, an optical writing head for a printer, and the like.

  It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention. That is, the specific materials and configurations described in the embodiments are merely examples, and can be changed as appropriate.

In the above embodiment, the bottom emission type organic EL device has been described as an example. However, the present invention can also be applied to a top emission type organic EL device. The pixel electrode of the top emission type organic EL device is made of a highly reflective metal material such as Al or Cr. However, in order to improve the hole injection property, ITO or IZO (registered trademark) is formed on the surface of the metal material. This is because a transparent conductive material such as
In the above embodiment, the organic EL device has been described as an example. However, in order to stably drive an organic semiconductor that actively uses an organic substance, the present invention can be applied to all organic semiconductors.

1 is a side cross-sectional view of an organic EL device according to a first embodiment. (A) is the schematic diagram of the cross section of an organic EL element, (b) is a chemical formula of polystyrene sulfonic acid. It is process drawing of the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. It is process drawing of the manufacturing method of the organic electroluminescent apparatus concerning 1st Embodiment. It is a comparison explanatory drawing of the organic electroluminescent apparatus (Example 1) which concerns on 1st Embodiment, and the organic electroluminescent apparatus (comparative example 1) which concerns on a prior art. It is a graph which shows the relationship between the air exposure time of a positive hole injection layer, and the lifetime of an organic EL element. It is side surface sectional drawing of the organic electroluminescent apparatus which concerns on 2nd Embodiment. It is process drawing of the manufacturing method of the organic electroluminescent apparatus concerning 2nd Embodiment. It is a comparison explanatory drawing of the organic electroluminescent apparatus (Example 2) which concerns on 2nd Embodiment, and the organic electroluminescent apparatus (comparative example 2) which concerns on a prior art. It is a perspective view of a mobile phone.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Air-conditioning chamber 23 ... Pixel electrode (anode, electrically conductive film) 25 ... Inorganic partition wall 52 ... Cathode 60 ... Light emitting layer 65 ... Hole transport layer 70 ... Hole injection layer

Claims (2)

A cathode and an anode containing a metal element;
A hole injection layer formed by drying a coating film of PEDOT / PSS, which is disposed adjacent to the anode between the anode and the cathode;
An organic film disposed adjacent to the hole injection layer between the anode and the cathode, and an organic EL device comprising:
The organic film includes a light emitting layer,
The hole injection layer contains 1.0 atm% or more of the metal element diffused from the anode ,
An organic EL device characterized in that a region from the interface between the hole injection layer and the organic film to 20 nm inside the organic film contains 0.2 atm% or more of the metal element diffused from the anode. .   An electronic apparatus comprising the organic EL device according to claim 1 in a display unit.

Images