JP2008277648A - Organic el element, and manufacturing method for organic el element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element whose life can be extended, and to provide a manufacturing method for the organic EL element. <P>SOLUTION: In the organic EL element, a light-emitting layer 12 contains a phosphorescent material, and a hole injection/transport layer 11 has a current density of 0.001 mA/cm<SP>2</SP>or more to 10 mA/cm<SP>2</SP>or less under electric field strength of 5×10<SP>5</SP>V/cm in a state where the hole injection/transport layer 11 is sandwiched between an anode layer 3 and a cathode layer 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic EL element and a method for producing the organic EL element.

  An organic EL (Electroluminescence) element is a light-emitting device having features such as thin, all-solid-state, planar self-emission, and high-speed response, and is expected to be applied to flat display panels and backlights. In recent years, high-efficiency organic EL elements that use phosphorescence resulting from the triplet excited state of a light-emitting material for light emission have been proposed. The phosphorescent material is attracting attention because it is considered that the phosphorescent material is easy to realize high efficiency in principle. That is, excitons generated by carrier recombination are composed of singlet excitons and triplet excitons, and the probability is 1: 3. In the organic EL element using singlet, the fluorescence at the time of transition from the singlet exciton to the ground state is taken out as light emission. In principle, the emission yield is 25% of the number of excitons generated. And this was the upper limit in principle. However, if phosphorescence from excitons generated from triplets is used, a yield of at least 3 times is expected in principle. Furthermore, by considering the transition due to intersystem crossing from singlet to triplet in terms of energy by using phosphorescence, a light emission yield of 100%, which is four times in principle, can be expected.

By the way, the materials constituting the organic light emitting layer in such an organic EL element are roughly classified into high molecular materials and low molecular materials. Since the polymer material has a relatively high solubility in an organic solvent, it can be selectively applied by a droplet discharge method such as an ink jet method. On the other hand, a low molecular weight material is superior in light emission characteristics as compared with a high molecular weight material.
In an organic EL element using a polymer material formed by a wet method such as a droplet discharge method, an organic film having high conductivity is used to promote hole injection from the hole injection layer to the light emitting layer. Is used as a hole injection layer (see, for example, Patent Documents 1 and 2).
JP 2005-276749 A JP 2005-276514 A

  However, the following problems remain in the conventional organic EL element. That is, in an organic EL device having a light emitting layer made of a phosphor material and made of a low molecular material, when a hole injection layer is formed of a material having high conductivity, excessive holes exist in the light emitting layer. Become. Therefore, there are a lot of holes that do not recombine with the injected electrons in the light emitting layer, and the inside of the light emitting layer is in a peroxidized state, or the electron transport layer is deteriorated by the holes transmitted through the light emitting layer. There's a problem.

  The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide an organic EL element capable of extending the lifetime and a method for manufacturing the organic EL element.

The present invention employs the following configuration in order to solve the above problems. That is, the organic EL device according to the present invention is an organic EL device in which a hole functional layer and a light emitting layer are provided between an anode layer and a cathode layer, and the light emitting layer contains a phosphorescent material, hole functional layer in a state of being sandwiched between the anode layer and the cathode layer, the current density is 0.001 mA / cm ² or more 10 mA / cm ² or less when the field strength and 5 × ¹⁰ 5 V / cm It is characterized by that.

The method for producing an organic EL device according to the present invention is a method for producing an organic EL device in which a hole functional layer and a light emitting layer are provided between an anode layer and a cathode layer, and the hole functional layer is formed. The step of performing the current density when the electric field strength between the anode layer and the cathode layer is 5 × 10 ⁵ V / cm with the hole functional layer sandwiched between the anode layer and the cathode layer. and a step of applying a liquid material containing 0.001 mA / cm ² or more 10 mA / cm ² or less and comprising a hole functional material, the step of forming the light emitting layer, applying a liquid material containing a phosphorescent material It has the process.

While in the present invention, by having a hole functional layer current density is 0.001 mA / cm ² or more 10 mA / cm ² or less when the field strength and 5 × ¹⁰ 5 V / cm, maintaining the luminous efficiency Long life can be achieved. That is, when the current density at which the electric field strength and 5 × ¹⁰ 5 V / cm is 0.001 mA / cm ² or more 10 mA / cm ² to below the hole functional layer resistivity, 5 × 10 ⁷ Ω · cm This is 5 × 10 ¹¹ Ω · cm or less. Thus, by setting the resistivity to 5 × 10 ⁷ Ω · cm or more, holes are prevented from being present in the light emitting layer. Thereby, it is possible to extend the life of the organic EL element by suppressing the light emitting layer from being oxidized. Moreover, luminous efficiency can be maintained by setting the resistivity to 5 × 10 ¹¹ Ω · cm or less.

In the organic EL device according to the present invention, the hole functional layer is sandwiched between the anode layer and the cathode layer, and the electric field strength between the anode layer and the cathode layer is 5 × 10 ⁵ V /. it is preferable that the current density when formed into a cm is 0.001 mA / cm ² or more 0.5 mA / cm ² or less.
In this invention, by a current density 0.001 mA / cm ² or more 5 mA / cm ² or less (the resistivity of 1 × 10 ⁹ Ω · cm or more 5 × ^{10 11} Ω · cm or less), more reliably luminous efficiency Can be maintained.

Moreover, the organic EL element concerning this invention is good also as the said positive hole functional layer having the granular material disperse | distributed and arrange | positioned inside.
In the present invention, the granular material is dispersed in the hole functional layer, whereby the resistivity of the hole functional layer is set to 5 × 10 ⁷ Ω · cm or more and 5 × 10 ¹¹ Ω · cm or less.

In the organic EL device according to the present invention, the surface of the hole functional layer may be modified.
In the present invention, the hole functional layer is subjected to a modification treatment so that the resistivity of the hole functional layer is 5 × 10 ⁷ Ω · cm or more and 5 × 10 ¹¹ Ω · cm or less.

[Organic EL device]
Hereinafter, one embodiment of an organic EL device according to the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size. Here, FIG. 1 is a schematic configuration diagram showing an organic EL element, and FIG. 2 is an explanatory diagram showing an evaluation element of a hole injection transport layer.

  As shown in FIG. 1, the organic EL element 1 in this embodiment includes a substrate 2, an anode layer 3, a light emitting functional layer 4, and a cathode layer 5 that are stacked on the upper surface of the substrate 2 in this order from the substrate 2 side. Yes. That is, the organic EL element 1 has a bottom emission structure in which light emitted from the light emitting functional layer 4 is emitted from the anode layer 3.

  The substrate 2 includes a driving element (not shown), a signal line (not shown), and a scanning line formed of a thin film transistor (hereinafter referred to as TFT) element on a substrate body made of a translucent material such as glass. (Not shown) is formed.

  The anode layer 3 is made of, for example, a transparent electrode such as ITO (Indium Tin Oxide), and is formed by patterning so as to be connected to the above-described drive elements, signal lines, scanning lines, and the like.

The light emitting functional layer 4 includes a hole injecting and transporting layer (hole functional layer) 11, a light emitting layer 12, and an electronic functional layer 13 that are sequentially stacked from the anode layer 3 side.
The hole injection transport layer 11 has a function of moving holes generated in the anode layer 3 toward the light emitting layer 12.
Here, as a hole injection transport material (hole functional material) constituting the hole injection transport layer 11, 3,4-polyethylenedioxythiophene / polystyrene sulfonic acid (PEDOT / PSS), a polythiophene derivative, a polyaniline derivative, Examples include polypyrrole derivatives and triarylamine derivatives. Examples of the triarylamine derivatives include TAPC (1,1-bis- (4-bis (4-methyl-phenyl) -amino-phenyl) -cyclohexane), TPD (4,4′-bis (N- (m- Tolyl) -N-phenylamino) biphenyl), α-NPD (4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl), m-MTDATA (4,4 ′, 4 ″- Tris (3-methylphenylphenylamino) triphenylamine), 2-TNATA (4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine), TCTA (4,4 ′, 4 ″ -tris) (N-carbazolyl) triphenylamine), spiro-TAD (2,2,7,7-tetra- (3-methyldiphenylamino) -9,9-spirobifluorene), (DTP) DPPD, HTM1 (N, N′-diphenyl-N, N′-bis (3-methylphenyl)-(1,1′-biphenyl) -4,4′-diamine), TPTE1, NTPA (4,4′- Bis (N- (4 ′-(N ″-(1-naphthyl) -N ″ -phenylamino) biphenyl) -N-phenylamino) biphenyl), TFLTF, and the like.

Further, fine particles 14 are dispersedly arranged in the hole injecting and transporting layer 11. The fine particles 14 are made of an insulator or a semiconductor such as inorganic oxides such as SiO ₂ (silicon dioxide), alumina and zirconia, and inorganic nitrides such as SiN (silicon nitride).
Here, the fine particles 14 have an average particle diameter of 0.5 nm or more and 100 nm or less, and are dispersed at a concentration of 0.1 wt% or more and 10 wt% or less with respect to the hole injection transport layer 11. In this way, by setting the average particle size of the fine particles 14 to 0.5 nm or more and 100 nm or less, it is possible to suppress the movement of holes in the hole injection transport layer 11 by the fine particles 14 and to inject from the anode layer 3. The function as the hole injection transport layer 11 for moving the generated holes to the light emitting layer 12 is maintained well. In addition, when the dispersion concentration of the fine particles 14 is 0.1 wt% or more and 10 wt% or less, the function as the hole injecting and transporting layer 11 is well maintained as described above.

A coating film for uniformly dispersing in a solvent or dispersion medium for dissolving or dispersing the hole injection / transport material may be formed on the surface of the fine particles 14. For example, when PEDOT / PSS is used as the hole injecting and transporting material, the surfactant is used as the coating film because the fine particles 14 are hydrophilic when they are composed of an inorganic oxide.
The hole injecting and transporting layer 11 sandwiches the hole injecting and transporting layer 11 between the anode layer 3 and the cathode layer 5 as shown in FIG. 2 by adjusting the constituent material, particle size, and dispersion amount of the fine particles 14. state, the current density when an electric field intensity with 5 × ¹⁰ 5 V / cm is in the 0.001 mA / cm ² or more 10 mA / cm ² or less. The hole injection transport layer 11 is preferably the current density when an electric field intensity with 5 × ¹⁰ 5 V / cm is 0.001 mA / cm ² or more 0.5 mA / cm ² or less.

The light emitting layer 12 is made of a low molecular material and includes a phosphorescent material capable of emitting phosphorescence. Here, examples of the phosphorescent material include PtOEP (platinum porphyrin complex), BtpIr (iridium complex), PAT (polyalkylthiophene), Ir (ppy) ₃ (iridium complex), FIrpic (iridium complex) derivative, and the like. PtOEP, BtpIr, and PAT are red phosphorescent materials, Ir (ppy) ₃ is a green phosphorescent material, and FIrpic is a blue phosphorescent material. The light emitting layer 12 may include a host material such as a CBP (4,4-dicarbazole-4,4-biphenyl) derivative. By using a phosphorescent material as a light emitting dopant for the host material, an organic EL element with high light emission efficiency can be obtained.

The electronic functional layer 13 has a configuration in which a hole blocking layer 15 and an electron injecting and transporting layer 16 are laminated in order from the light emitting layer 12 side.
The hole blocking layer 15 has a function of preventing holes that have passed through the light emitting layer 12 without recombining with electrons in the light emitting layer 12 from reaching the electron injecting and transporting layer 16. This prevents excessive holes from being present in the electron injection / transport layer 16 and prevents the electron injection / transport layer 16 from deteriorating due to an oxidation reaction.
Here, examples of the hole blocking material constituting the hole blocking layer 15 include triazole derivatives, polyvinyl pyridine, and polyvinyl pyrrolidone, which have a higher band barrier than the light emitting layer 12 for hole injection.

  The electron injection / transport layer 16 has a function of moving electrons generated in the cathode layer 5 toward the light emitting layer 12. Here, as an electron injecting and transporting material constituting the electron injecting and transporting layer 16, an anthraquinone derivative, an oxadiazole derivative, an oxazole derivative, a phenanthroline derivative, an anthraquinodimethane derivative, a benzoquinone derivative, a naphthoquinone derivative, a tetracyanoanthraquinodimethane Derivatives, fluorenone derivatives, diphenyldicyanoethylene derivatives, diphenoquinone derivatives, metal complexes of hydroxyquinoline derivatives, and the like.

  The cathode layer 5 is formed on the electron injecting and transporting layer 16, and has a configuration in which a LiF (lithium fluoride) layer, a Ca (calcium) layer, and an Al (aluminum) layer are stacked in order from the upper surface of the electron injecting and transporting layer 16. It has become. A sealing layer (not shown) is formed on the cathode layer 5.

[Method for producing organic EL element]
Next, a method for manufacturing the organic EL element 1 having the above configuration will be described.
First, the substrate 2 is formed. Here, TFT elements, signal lines, scanning lines, insulating films, and the like are formed on the above-described substrate body.
Next, the anode layer 3 is formed on the substrate 2. Here, an ITO film is formed on the substrate 2 by vapor deposition or the like and patterned. Here, after cleaning the substrate 2 on which the anode layer 3 is formed, an oxygen plasma treatment is performed at atmospheric pressure to modify the surface of the anode layer 3 to be lyophilic.

  Subsequently, the hole injection transport layer 11 is formed on the anode layer 3. Here, a liquid material in which a hole injecting and transporting material is dissolved or dispersed in a solvent or a dispersion medium is applied onto the anode layer 3 by a droplet discharge method such as an ink jet method. Here, as the solvent or dispersion medium for dissolving or dispersing the hole injecting and transporting material, for example, a nonpolar solvent such as cyclohexylbenzene, dihydrobenzofuran, trimethylbenzene, toluene, xylene, and a mixture thereof is used. Then, the applied liquid is dried to remove the solvent, and the hole injection transport layer 11 is formed.

Next, the light emitting layer 12 is formed on the hole injecting and transporting layer 11. Here, a liquid material in which a light emitting material is dissolved in a solvent is applied onto the hole injecting and transporting layer 11 by a droplet discharge method such as an ink jet method as described above. Then, the applied liquid is dried to remove the solvent, and the light emitting layer 12 is formed.
Subsequently, the hole blocking layer 15 is formed on the light emitting layer 12. Here, a liquid material in which a hole blocking material is dissolved or dispersed in a solvent or a dispersion medium is applied onto the light emitting layer 12 by a droplet discharge method such as an ink jet method as described above. Then, the applied liquid is dried to remove the solvent or the dispersion medium, and the hole blocking layer 15 is formed.

Next, the electron injecting and transporting layer 16 is formed on the hole blocking layer 15. Here, a liquid material in which an electron injecting and transporting material is dissolved or dispersed in a solvent or a dispersion medium is applied onto the hole blocking layer 15 by a droplet discharge method such as an ink jet method as described above. Then, the applied liquid is dried to remove the solvent or the dispersion medium, and the electron injecting and transporting layer 16 is formed.
Subsequently, the cathode layer 5 is formed on the light emitting layer 12. Here, the LiF layer, the Ca layer, and the Al layer are sequentially formed on the light emitting layer 12 by a vacuum deposition method or the like. Thereafter, the sealing layer is formed on the cathode layer 5. The organic EL element 1 is manufactured as described above.

Here, Table 1 and FIG. 3 show the results of measuring the half life of the luminance of Samples 1 to 6 in which the dispersion amount of the fine particles 14 in the hole injecting and transporting layer 11 is changed. In Table 1 and FIG. 3, the hole injection transport layer 11 is sandwiched between the anode layer 3 and the cathode layer 5, and the electric field strength between the anode layer 3 and the cathode layer 5 is set to 5 × 10 ⁵ V / cm. The current density in the hole injecting and transporting layer 11 and the resistivity at that time are shown. Moreover, in Table 1 and FIG. 3, the half life of the brightness | luminance when using Ir (ppy) ₃ (green phosphorescence) and Pt (OEP) (red phosphorescence) as a phosphorescent material which comprises the light emitting layer 12 in each sample, respectively is shown. Show.
At this time, the luminance in the initial state when using Ir (ppy) ₃ is 4000 cd / m ² , and the luminance in the initial state when using Pt (OEP) is 2000 cd / m ² . Further, PEDOT / PSS is used as the hole injection / transport material constituting the hole injection / transport layer 11. As the hole blocking material constituting the hole blocking layer 15, a triazole derivative such as BAlq (bis (2methyl-8-quinolinolato) (paraphenylphenolato) aluminum complex) is used. Furthermore, an anthraquinone derivative such as Alq ₃ (Tris-8-quinolinolato aluminum complex) is used as the electron injection / transport material constituting the electron injection / transport layer 16.

As shown in Table 1 and Figure 3, 10mA / cm ² or less current density 0.001 mA / cm ² or more when the electric field strength and 5 × ¹⁰ 5 V / cm (resistivity of 5 × 10 ⁷ Ω · cm It can be seen that by using the hole injecting and transporting layer 11 of 5 × 10 ¹¹ Ω · cm or less, the lifetime can be extended while maintaining the luminous efficiency. In addition, by setting the current density in the hole injection transport layer 11 0.001 mA / cm ² or more 5 mA / cm ² or less (the resistivity of 1 × 10 ⁹ Ω · cm or more 5 × ^{10 11} Ω · cm or less), Luminous efficiency can be maintained more reliably.

The organic EL element 1 having the above configuration constitutes an organic EL display device 50 as shown in FIGS. 4 and 5, for example. 4 is a schematic plan view showing the organic EL display device, and FIG. 5 is an equivalent circuit diagram showing the organic EL display device.
As shown in FIG. 4, the organic EL display device 50 includes an actual display area 51a (area surrounded by a two-dot chain line in FIG. 4) and an actual display area 51a in the central portion of the substantially rectangular substrate 2 in plan view. A pixel portion 51c (indicated by a one-dot chain line in FIG. 4) composed of a dummy region 51b (between a region surrounded by a one-dot chain line in FIG. 4 and a region surrounded by a two-dot chain line) in FIG. An enclosed area) is provided.

  Further, the actual display area 51a of the organic EL display device 50 is provided with a plurality of pixel areas A, a plurality of data lines 52, a scanning line 53, and a power supply line 54 arranged in a grid pattern as shown in FIG. ing. In the dummy area 51b of the organic EL display device 50, as shown in FIGS. 4 and 5, a data line driving circuit 55 and a scanning line driving circuit 56 are provided. Further, as shown in FIG. 4, cathode wiring 57 connected to the cathode layer 5 is provided outside the pixel portion 51 c of the organic EL display device 50.

As shown in FIG. 5, the plurality of pixel regions A are provided with an anode layer 3 serving as a pixel electrode, TFT elements 61 and 62 for switching control of the anode layer 3, and a storage capacitor 63, respectively. .
The TFT element 61 has a gate connected to the scanning line 53, a source connected to the data line 52, and a drain connected to the TFT element 62 and the storage capacitor 63. The TFT element 61 is configured to supply an image signal supplied via the data line 52 to the storage capacitor 63 in accordance with the scanning signal supplied via the scanning line 53.
The TFT element 62 has a gate connected to the drain of the TFT element 61, a source connected to the power supply line 54, and a drain connected to the anode layer 3. The TFT element 62 is configured to supply a drive current supplied via the power line 54 to the anode layer 3 in accordance with the image signal supplied via the storage capacitor 63.

The data lines 52, the scanning lines 53, and the power supply lines 54 are arranged in a grid pattern in the actual display area 51a. The data line 52 is connected to the data line driving circuit 55, and the scanning line 53 is connected to the scanning line driving circuit 56.
The TFT elements 61 and 62, the storage capacitor 63, the data line 52, and the scanning line 53 are formed on the substrate 2 described above.
A partition wall (not shown) that partitions each pixel region A is provided on the substrate 2. The light emitting functional layer 4 in each pixel region A is partitioned from the light emitting functional layer 4 in the adjacent pixel region A by a partition. The cathode layer 5 is formed integrally with the cathode layers 5 of the plurality of organic EL elements 1 arranged in the actual display area 51a.

〔Electronics〕
The organic EL display device 50 configured as described above is used as a display unit 101 of a cellular phone (electronic device) 100 as shown in FIG. The cellular phone 100 includes a display unit 101, a plurality of operation buttons 102, an earpiece 103, a mouthpiece 104, and a main body unit including the display unit 101.

As described above, according to the organic EL element 1 and the method for manufacturing the organic EL element in the present embodiment, the current density when the electric field strength is 5 × 10 ⁵ V / cm is 0.001 mA / cm ² or more and 10 mA / cm. If it is set to cm ² or less, the resistivity of the hole functional layer becomes 5 × 10 ⁷ Ω · cm or more and 5 × 10 ¹¹ Ω · cm or less. Here, by setting the resistivity to 5 × 10 ⁷ Ω · cm or more, it is possible to prevent the presence of holes in the light emitting layer and to prolong the lifetime of the organic EL element. The luminous efficiency can be maintained by setting the resistivity to 5 × 10 ¹¹ Ω · cm or less. In addition, by a current density 0.001 mA / cm ² or more 0.5 mA / cm ² or less (the resistivity of 1 × 10 ⁹ Ω · cm or more 5 × ^{10 11} Ω · cm or less), more reliably luminous efficiency Can be maintained.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the resistivity of the hole injection / transport layer is set to 5 × 10 ⁷ Ω · cm or more and 5 × 10 ¹¹ Ω · cm or less by dispersing and disposing fine particles. The resistivity of the hole injecting and transporting layer may be adjusted by using other methods. Here, as the modification treatment, after forming the hole injecting and transporting layer, the surface is irradiated with UV ozone, oxygen plasma, or CF ₄ (tetrafluoromethane) plasma, and annealing treatment is performed. In addition, when forming the hole injecting and transporting layer using a wet method such as a droplet discharge method, the heating temperature or heating atmosphere (for example, oxygen atmosphere or nitrogen atmosphere) at the time of drying to remove the solvent or dispersion medium is set. The modification treatment may be performed by adjusting. As the modification treatment, it is preferable to use a treatment that does not significantly damage the surface shape of the hole injecting and transporting layer.
The resistivity of the hole injecting and transporting layer is set to 5 × 10 ⁷ Ω · cm or more and 5 × 10 ¹¹ Ω · cm or less by dispersing and arranging fine particles, but the resistivity is 5 × 10 ⁷ Ω · cm or more in advance. A material of 5 × 10 ¹¹ Ω · cm or less may be used as the hole injecting and transporting layer material.

  In addition, the hole injecting and transporting layer, the light emitting layer, the hole blocking layer, and the hole injecting and transporting layer are formed by a droplet discharge method such as an ink jet method, but are formed using another wet method such as a spin coating method. May be.

In addition, the hole functional layer is composed only of the hole injection / transport layer, but either the structure in which the hole injection layer and the hole transport layer are stacked or the hole injection layer and the hole transport layer are either It is good also as a structure which provides an electronic block layer between the structure which has only this, and a light emitting layer. Here, the electron block layer has a function of preventing electrons from reaching the anode layer.
The electron functional layer is configured by stacking an electron injection / transport layer and a hole blocking layer. Similarly to the above, the electron functional layer is configured by stacking an electron injection layer and an electron transport layer, or an electron injection layer and an electron transport layer. It is good also as a structure which has only any of a transport layer, and a structure which does not provide a positive hole block layer.

Moreover, although the organic EL element has a configuration in which an anode layer is provided on a substrate, a configuration in which a cathode layer is provided on the substrate may be employed. That is, the light emitting layer may be formed above the cathode layer, and the hole functional layer may be formed on the light emitting layer.
The organic EL element has a bottom emission structure that emits light from the lower surface side of the substrate, but may have a top emission structure that emits light from the upper surface side of the substrate. At this time, the electrode layer formed above the light emitting functional layer is formed of a light-transmitting conductive material such as ITO.

It is a schematic sectional drawing which shows the organic EL element in one Embodiment of this invention. It is explanatory drawing which shows the evaluation element of the resistivity of a positive hole injection transport layer. It is a graph which shows the relationship between the resistivity of a positive hole injection transport layer, and a brightness | luminance half life. It is a schematic plan view which shows an organic electroluminescence display. FIG. 5 is an equivalent circuit diagram of FIG. 4. It is a schematic perspective view which shows a mobile telephone provided with an organic electroluminescence display.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic EL element, 3 Anode layer, 5 Cathode layer, 11 Hole injection transport layer (hole functional layer), 12 Light emitting layer, 14 Fine particle, 50 Organic EL display apparatus (display apparatus)

Claims (5)

An organic EL device in which a hole functional layer and a light emitting layer are provided between an anode layer and a cathode layer,
The light emitting layer contains a phosphorescent material;
The hole functional layer in a state of being sandwiched between the anode layer and the cathode layer, the current density when an electric field intensity with 5 × ¹⁰ 5 V / cm is 0.001 mA / cm ² or more 10 mA / cm ² or less An organic EL element characterized by: The hole functional layer has a current density of 0.001 mA / cm ² or more and 0.5 mA / cm when the electric field strength is 5 × 10 ⁵ V / cm while being sandwiched between the anode layer and the cathode layer. The organic EL device according to claim 1, wherein the organic EL device is ² or less.   The organic EL device according to claim 1, wherein the hole functional layer has a granular material dispersed inside.   The organic EL device according to any one of claims 1 to 3, wherein a surface of the hole functional layer is subjected to a modification treatment. A method for producing an organic EL device in which a hole functional layer and a light emitting layer are provided between an anode layer and a cathode layer,
In the step of forming the hole functional layer, the electric field strength between the anode layer and the cathode layer is 5 × 10 ⁵ V / cm with the hole functional layer sandwiched between the anode layer and the cathode layer. and a step of applying a liquid material containing the hole functional material current density is 0.001 mA / cm ² or more 10 mA / cm ² or less when formed into a,
The method of manufacturing an organic EL element, wherein the step of forming the light emitting layer includes a step of applying a liquid material containing a phosphorescent material.

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