JP2001257076A - Organic el element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an organic EL element which enables to achieve reliability of thermal stability and the like and high efficiency in the high brightness region at the same time by doping a triplet luminous material in an organic host material, particularly, in a non-conjugated unsaturated polymer. SOLUTION: The organic EL element comprises a hole injecting electrode, an electron injecting electrode and a luminous layer composed of an organic host material and a dopant disposed between these electrodes. The above organic material is made of a non-conjugated unsaturated polymer material and the above dopant is made of an organic metal complex capable of phosphorescence from a triplet state and contains at least a metal ion belonging to the VII family of the Mendeleyev periodic table.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic EL device using an organic material and having a light-emitting / display function by electroluminescence (EL).

[0002]

2. Description of the Related Art An organic EL device is a thin film made of a low molecular hole transporting material such as a hole injection electrode triphenyldiamine (TPD) by a vacuum deposition method or the like, and a low molecular weight material such as an aluminum quinolinol complex (Alq3) is formed thereon. of the fluorescent material was laminated as a light emitting layer, further a small metal electrode element having a basic structure forming the (electron injection electrode) work function such as Mg, 10V tens of thousands cd / m ² from thousands before and after voltage Attention has been paid to obtaining extremely high luminance.

On the other hand, an organic EL device using a polymer material has also been reported. By using a polymer material, it is possible to improve the thermal stability and simplify the process by coating, which are problems with the molecular material, and R & D is being conducted mainly in Europe and the United States.

[0004] Polymer organic EL devices can be broadly classified into a π-conjugated type using a conjugated polymer and a molecular dispersion type in which a dye is dispersed in a non-conjugated polymer. The π-conjugated type has been studied mainly in Europe and the United States since the presentation by Cambridge University (Nature 347, 539-541, 1990), and now it is possible to create high-brightness devices comparable to low-molecular-weight deposition systems used to be a long time ago. Have been. However, a π-conjugated material is basically a material through which an electric current can easily flow, and thus can emit light at a low voltage. On the contrary, in a high luminance region such as several thousands to tens of thousands cd / m ² , Efficiency is low and heat is intense. Therefore, the duty (Dut
y) It is difficult to use for a passive matrix display or the like that requires driving.

On the other hand, the molecular dispersion type was used in 1883 (Polyme
r, Vol, 24, 748-754, 1983), which was early and long in history, but only about 1/10 or less of the properties were obtained compared to the low molecular weight type and the π-conjugated type.

Incidentally, the conventional organic EL element utilizes fluorescence from a light emitting material. When the material is in the excited state, the singlet state occupies 25% and the triplet state occupies 75%. Therefore, in the conventional organic EL device, the energy of the triplet state becomes heat and does not contribute to light emission.

An attempt to use the energy of the triplet state for EL emission has been made by Hoshino et al. (Appl. Phys. Lett. 69, 224-226 (1996)). More efficient devices have been created by a group at Princeton University (Nature 395, 151-154, 1998). It has been reported that a device using this triplet light-emitting material exhibits several times the luminance and efficiency as compared with a conventional organic EL device using light emission from only a singlet. However, since the device is formed by a vapor deposition method using a low-molecular material, problems such as a lack of reliability such as thermal stability and a complicated process due to a complicated device configuration cannot be solved.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to dope a triplet light-emitting material into an organic host material, particularly a non-conjugated polymer, to obtain a material having high thermal stability and reliability. An object of the present invention is to realize an organic EL device that can simultaneously improve efficiency.

[0009]

[Action] When a triplet luminescent material is doped into a π-conjugated polymer in which molecules easily associate with each other and easily form excimers, exciplex formation and recombination may occur.
Since the obtained energy was transferred to the excimer array formed by the π-conjugated polymers, light could not be effectively extracted from the triplet luminescent material. On the other hand, organic host materials, particularly preferably non-conjugated polymers having a carbazole unit, can effectively extract light without forming an exciplex, and the luminance and luminous efficiency are 10 times higher than those of a conventional device. Also reached.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An organic EL device according to the present invention has a hole injection electrode, an electron injection electrode, and a light emitting layer composed of an organic host material and a dopant between these electrodes. Wherein the dopant is an organometallic complex capable of emitting phosphorescence from a triplet state and contains at least a metal ion belonging to Group VIII of the Mendeleev periodic table.

As described above, a non-conjugated polymer material having a carbazole group is preferably used as the organic host material for forming the light-emitting layer, and the non-conjugated polymer material belongs to Group VIII capable of emitting phosphorescence from a triplet state. By doping an organic metal complex containing a metal ion, extremely efficient light emission can be performed.

The organic host material preferably has a charge transporting property, and particularly preferably has a hole transporting property.

Further, the polymer material preferably has a carbazole group. Specifically, a carbazole compound represented by the following general formula (I) can be given.

[0014]

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In the above formula (I), R ¹ and R ² represent hydrogen or an alkyl group having 1 to 18 carbon atoms, and X represents 1
Represents a 3- to 3-ring phenyl group or an alkylene group. The molecular weight of the compound of formula (I) is preferably Mw =
It is 10,000-100,000. R ¹ and R ² may further have a substituent.

Further, a carbazole compound represented by the following formula (II) may be used.

[0017]

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In the above formula (II), R ³ and R ⁴ represent hydrogen or an alkyl group having 1 to 18 carbon atoms, and Y represents 1
Represents a 1 to 3 ring phenyl group, an alkylene group or a xylylene group, and Ar represents a 1 to 4 ring phenyl group, particularly preferably a benzene, anthracene or naphthacene derivative.
R ³ and R ⁴ and Y and Ar may further have a substituent.

As the phenyl group represented by X and Ar,
Particularly, a monocyclic phenyl group is preferable.

As the non-conjugated polymer which is an organic host material represented by the formula (I), a polymer compound having a repeating unit represented by the following formula is particularly preferable.

[0021]

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In the above formula, preferably Mw = 10,
000 to 100,000. By combining such a non-conjugated polymer material and the metal complex,
The effect can be further enhanced.

As the organic host material represented by the formula (II), those shown below are particularly preferable.

[0024]

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[0025]

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[0026]

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The energy gap Eg of such an organic host material is preferably 2.4 eV or more, particularly preferably 2.9 to 3.6 eV.

In the present invention, the organic host material may have 3
A compound capable of emitting phosphorescence from a multiplet state is doped.
The organic compound capable of emitting phosphorescence is an organometallic complex capable of emitting phosphorescence from a triplet state, and at least Group VIII of the periodic table of Mendel, that is, Fe, Co, Ni, Ru,
It is a metal complex containing a metal ion selected from Rh, Pd, Os, Ir and Pt, preferably an Ir or Pt ion.

As such a metal complex, ligands represented by the following [Formula 7] and [Formula 8] are preferable.
In the following formula, M represents the above central metal, and R
₁₀₁ and R ₁₀₂ are not particularly limited, but are preferably an alkyl group or an alkoxy group having 1 to 3 carbon atoms.

[0030]

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[0031]

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The specific structure of such a complex is as follows:
For example, the following are mentioned.

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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Further, the following platinum complexes (2,3,7,8,12,1)
3,17,18-Octaethyl -21H, 23H-porphine platinum) and the like are also preferable, and among these, an iridium complex: tris (2-phenylpyridine) iridium [Ir (ppy) 3] is particularly preferable. In the following formula, M represents the above central metal, and Pt is particularly preferable.

[0040]

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The content of these metal complexes in the light emitting layer is preferably from 0.1 to 10 mol%, particularly from 1 to 10 mol%, based on all components.

The organic host material is a material having a charge transporting property, preferably a hole transporting property. When the organic host material has a hole transporting property, an electron transporting material may be mixed in the light emitting layer. As the electron transporting material, a low molecular organic compound used in a conventional vapor deposition system can be used, but a polymer material may be used.

Specifically, AlQ3 (tris (8-hydroxy-quinolino) aluminum), BeQ2 (bis (8-hydroxy-quinolino) beryllium), Zn (B
OZ) 2 (zinc-bis-benzoxazole), Zn (B
TZ) 2 (zinc-bis-benzothiazole), Eu (D
BM) 3 (Phen) (tris (1,3-diphenyl-
1,3-propanediono) (monophenanthroline) europium (III), PBD (2- (4-biphenyl) -5- (4-tert-butylphenyl) -1,
3,4-oxadiazole), Butyl-PBD (2
-Biphenyl-5- (para-tert-butylphenyl) -1,3,4-oxadiazole), TAZ (1-
Phenyl-2-biphenyl-5-para-tert-butylphenyl-1,3,4-triazole) and the like.

The content of such an electron transporting material is from 10 to 50% by mass, especially from 20 to 40% by mass based on all components of the light emitting layer.
% By mass is preferred.

The above-mentioned light emitting layer may be formed singly or may be composed of a plurality of layers. When it is composed of a plurality of layers, the hole transporting layer and the electron transporting layer may be formed separately. Further, the organic host material or another constituent material may have a concentration gradient in the film thickness direction. When there are a plurality of layers or when there is a concentration gradient, it is preferable that the electron transporting material be more present on the negative electrode side and the hole transporting material be present more on the hole injection electrode side.

The charge transporting ability of the material used for the light emitting layer is 10 ⁻² to 10 by hole drift mobility.
^-5 cm ² / Vs is preferred, more preferably 10 ^-3 cm
² / Vs or more. In addition, room temperature dark conductivity, 10 ^-11 ~
10 ⁻⁹ Scm ⁻¹ is preferred, and more preferably 10 ⁻¹⁰ Scm
^-1 or more.

The organic EL device of the present invention may have an electrode interface improving layer between the hole injection electrode and the light emitting layer.

As the electrode interface modification layer, an organic polymer layer containing polydioxythiophenes is preferable.

The above polydioxythiophenes are preferably cationically charged in the presence of a polyanion and contain a structural unit represented by the formula (III).

[0050]

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[In the formula, A ¹ and A ² each independently represent a substituted or unsubstituted alkyl group having 1 to 14 carbon atoms, or together form a substituted or unsubstituted alkyl group having 1 to 14 carbon atoms. ~ 14 alkylenes and n is from 2 to 10,000, preferably from 5 to 5000
Represents the integer of

Preferred cationic polydioxythiophenes are those containing a structural unit represented by the following formula (IIIa) or (IIIb).

[0053]

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[Wherein R ¹¹ and R ¹² independently of one another are hydrogen, a substituted or unsubstituted alkyl group having 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, particularly 1 to 6 carbon atoms.
An alkyl group, an alkenyl group having 2 to 12 carbon atoms, preferably an alkenyl group having 2 to 8 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, preferably a cyclopentyl group or a cyclohexyl group, having 7 to 15 carbon atoms. An aralkyl group, preferably a phenyl-alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, preferably a phenyl group or a naphthyl group, an alkyloxy group having 1 to 18 carbon atoms, preferably a carbon number 1 to
10 alkyloxy group such as methoxy group, ethoxy group, n- or iso - such as propoxy, or an alkyloxy ester group having 2 to 18 carbon atoms, and R ^13, R ^{1 4} independently of one another, Both are not simultaneous but represent hydrogen or each have 1 to 18 carbon atoms, preferably 1 to 10 carbon atoms, especially 1 to 6 carbon atoms, each being substituted by at least one sulfonate group. An alkyl group, an alkenyl group having 2 to 12 carbon atoms, preferably an alkenyl group having 2 to 8 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, preferably a cyclopentyl group or a cyclohexyl group, having 7 to 15 carbon atoms. An aralkyl group, preferably a phenyl-alkyl group having 1 to 4 carbon atoms, an aryl group having 6 to 10 carbon atoms, preferably a phenyl or naphthyl group, an alkyl group having 1 to 18 carbon atoms. Group, preferably having 1 to 10 carbon atoms
Alkyloxy group such as methoxy group, ethoxy group,
n- or iso-propoxy group or the like, or 2 carbon atoms
-18 alkyloxyester groups, n representing a number from 2 to 10,000, preferably from 5 to 5000]

Particularly preferably, it contains at least one cationic or uncharged conductive compound represented by the following formula (IIIa-1) or (IIIb-1).

[0056]

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[Wherein, R ¹⁵ has the same meaning as R ¹³ and R ¹⁴ described above, and n represents an integer of 2 to 10,000, preferably 5 to 5000]. Electrochromic polydioxythiophene is included.

The polyanion is a polymer carboxylic acid,
For example, polyacrylic acid, anion such as polymethacrylic acid or polymaleic acid, or polymeric sulfonic acid,
For example, anions such as polystyrene sulfonic acid and polyvinyl sulfonic acid. Such polycarboxylic acids and polysulfonic acids may also be copolymers made from vinylcarboxylic acids and vinylsulfonic acids and other polymerizable monomers such as acrylates and styrene.

As a counter ion, an anion of polystyrene sulfonic acid is particularly preferred.

The molecular weight of the polyacids giving the polyanions is preferably between 1000 and 2,000,000, particularly preferably between 2000 and 500,000. Such polyacids or their alkali metal salts, such as polystyrenesulfonic acid and polyacrylic acid, are commercially available or can be prepared by known methods (eg, Houben-Weyl, Methoden).
der organischen Chemie, E2
Volume 0 Makromolekulare Stoffe,
Part 2, (1987), pages 1141 et seq.).

Instead of the free polyacid required to form a dispersion of polydioxythiophenes and polyanions, it is also possible to use a mixture of the above-mentioned alkali metal salts of polyacids and corresponding amounts of monoacids. It is possible.

The polydioxythiophenes of the formula (IIIb-1) have a positive charge and a negative charge in their structural units. The production of such polydioxythiophenes is described, for example, in EP-A-0 440 957 (= US Pat. No. 5,300,575).

Such polydioxythiophenes are obtained by oxidative polymerization. As a result, they acquire a positive charge, but they are not shown in the formula, since their valence and position cannot be determined unambiguously.

These polymer compounds are dissolved in a solvent,
A desired polymer layer can be formed on the substrate by coating, casting, dipping, or the like.

The solvent for these polymer compounds is not particularly limited, and a suitable one can be selected from known materials. Specifically, an organic solvent such as toluene, xylene, or chloroform, alcohol, or water may be used depending on the material.

In the present invention, the substrate on which the organic EL structure is formed is an amorphous substrate such as glass or quartz, or a crystalline substrate such as Si, GaAs, ZnSe, or Z.
Examples thereof include nS, GaP, and InP, and a substrate in which a crystalline, amorphous, or metal buffer layer is formed on these crystalline substrates can also be used. As the metal substrate, Mo, Al, Pt, Ir, Au, Pd, or the like can be used, and a glass substrate is preferably used. When the substrate is on the light extraction side, it is preferable that the substrate has the same light transmittance as the following electrodes.

As the electron injection electrode, a substance having a low work function is preferable. For example, Cs, K, Li, Na, Mg, L
a, Ce, Ca, Sr, Ba, Al, Ag, In, S
It is preferable to use a single metal element such as n, Zn, or Zr, or a two-component or three-component alloy system containing them to improve stability. As an alloy system, for example, Ag · M
g (Ag: 0.1 to 50 at%), Al.Li (Li:
0.01-14 at%), In.Mg (Mg: 50-80)
at%), Al.Ca (Ca: 0.01 to 20 at%), L
iF (F: 40 to 60 at%) and the like are preferable. The electron injection electrode may be used also as the wiring electrode, or may be formed separately. The electron injection electrode can be formed by an evaporation method or a sputtering method.

The thickness of the electron injecting electrode thin film may be a certain thickness or more for sufficiently injecting electrons.
Preferably, the thickness may be 1 nm or more. The upper limit is not particularly limited, but the thickness may be generally about 1 to 500 nm.

The hole injection electrode usually emits light from the substrate side.
Because it is a structure that extracts light, it is transparent or translucent.
Pole is preferred. ITO (tin-doped acid)
Indium oxide), IZO (zinc-doped indium oxide)
), ZnO, SnO_Two, In_TwoO _ThreeAnd the like,
Preferably ITO (tin-doped indium oxide), IZO
(Zinc-doped indium oxide) is preferred. ITO
Normal In_TwoO_ThreeAnd SnO in a stoichiometric composition,
The amount of O may slightly deviate from this.

The hole injection electrode has an emission wavelength band, usually 3
50 to 800 nm, especially 50% light transmittance for each emitted light.
%, Especially 60% or more. Normal,
Since the emitted light is extracted through the hole injection electrode, if the transmittance is low, the emission itself from the light emitting layer is attenuated, and the luminance required for the light emitting element tends not to be obtained. However, when the emitted light is extracted from only one side, the side from which the emitted light is extracted need only be equal to or more than the above.

The thickness of the hole injecting electrode may be a certain thickness or more which can sufficiently inject holes, and is preferably 5 or more.
The range is preferably from 0 to 500 nm, more preferably from 50 to 300 nm. The upper limit is not particularly limited, but if the thickness is too large, there is a fear of peeling or the like. If the thickness is too small, there is a problem in the film strength at the time of manufacturing, the hole transport ability, and the resistance value.

This hole injection electrode layer can be formed by a vapor deposition method or the like, but is preferably formed by a sputtering method.

Further, in order to prevent oxidation of the organic layer and the electrodes of the element, it is preferable to seal the element with a sealing plate or the like. The sealing plate adheres and seals the sealing plate using an adhesive resin layer in order to prevent moisture from entering. The sealing gas is A
An inert gas such as r, He, and N ₂ is preferable. Further, the moisture content of the sealing gas is preferably 100 ppm or less, more preferably 10 ppm or less, and particularly preferably 1 ppm or less. Although there is no particular lower limit for the water content, it is usually about 0.1 ppm.

The material of the sealing plate is preferably a flat plate, and may be a transparent or translucent material such as glass, quartz, resin, etc., and glass is particularly preferred. As such a glass material, an alkali glass is preferable from the viewpoint of cost, and in addition, a glass composition such as soda lime glass, lead alkali glass, borosilicate glass, aluminosilicate glass, and silica glass is also preferable. In particular, soda glass, a glass material without surface treatment can be used at low cost,
preferable. As the sealing plate, other than a glass plate, a metal plate, a plastic plate, or the like can be used.

The height of the sealing plate may be adjusted by using a spacer, and may be maintained at a desired height. Examples of the material of the spacer include resin beads, silica beads, glass beads, and glass fibers, and glass beads are particularly preferable. When a recess is formed in the sealing plate, the spacer may or may not be used.

The spacer may be mixed in the sealing adhesive in advance, or may be mixed at the time of bonding. The content of the spacer in the sealing adhesive is preferably 0.01
-30 wt%, more preferably 0.1-5 wt%.

The adhesive is not particularly limited as long as it can maintain stable adhesive strength and has good airtightness, but it is preferable to use a cationic curing type ultraviolet curing epoxy resin adhesive. .

The emission color may be controlled by using a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film on the substrate.

As the color filter film, a color filter used in a liquid crystal display or the like may be used.
The characteristics of the color filter may be adjusted in accordance with the light emitted from the organic EL element to optimize the extraction efficiency and the color purity.

When a color filter capable of cutting off short-wavelength external light that is absorbed by the EL element material or the fluorescence conversion layer is used, the light resistance of the element and the contrast of display are improved.

An optical thin film such as a dielectric multilayer film may be used instead of the color filter.

The fluorescence conversion filter film absorbs EL light and emits light from the phosphor in the fluorescence conversion film to convert the color of emitted light. The composition includes a binder, It is formed from a fluorescent material and a light absorbing material.

As the fluorescent material, basically, a material having a high fluorescence quantum yield may be used, and it is desirable that the fluorescent material has strong absorption in the EL emission wavelength region. In practice, laser dyes and the like are suitable, and rhodamine compounds, perylene compounds, cyanine compounds, phthalocyanine compounds (including subphthalocyanines, etc.) naphthalimide compounds, condensed ring hydrocarbon compounds, condensed heterocyclic compounds A styryl compound, a coumarin compound or the like may be used.

As the binder, basically, a material that does not quench the fluorescence may be selected, and a binder that can be finely patterned by photolithography, printing, or the like is preferable. Further, in the case of being formed on the substrate in contact with the hole injection electrode, a material which is not damaged when forming the hole injection electrode (ITO, IZO, or the like) is preferable.

The light absorbing material is used when the light absorption of the fluorescent material is insufficient, but may be omitted when unnecessary. As the light absorbing material, a material that does not quench the fluorescence of the fluorescent material may be selected.

The organic EL device of the present invention has, for example, a normal lamination in which a substrate 1 / hole injection electrode 2 / electrode interface modification layer 3 / light emitting layer 4 / electron injection electrode 5 are sequentially stacked as shown in FIG. Configuration. In addition, the stacking order may be reversed, and an optimum stacking configuration may be set according to required performance and specifications.

The organic EL element is driven by a direct current or a pulse, and can be driven by an alternating current. The applied voltage is usually 2
It is about 30V.

The organic EL device of the present invention can be applied to various optical applications such as an optical pickup used for memory read / write, a relay device in a transmission line of optical communication, a photocoupler, etc. in addition to a display application. Can be used for devices.

[0089]

<Example 1> An ITO substrate was subjected to ultrasonic cleaning in the order of a neutral detergent, ultrapure water, acetone and ethanol.
A V / O ₃ wash was performed.

Poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate [Poly (3,4) ethylened
[Ioxythiophen-polystyrenesulphonate (PEDOT / PSS)] was formed on an ITO substrate by a spin coat method to form a film having a thickness of 50 nm, followed by vacuum drying at 110 ° C. for 1 hour to form a hole injection electrode.

Polyvinylcarbazole (Polyvinylcarbazole (PVK)) which is a hole-transporting material was used as an electron-transporting material and 2- (4'-tert-butylphenyl) -5-
(4'-biphenyl) -1,3,4-oxadiazole [2- (4'-tert-Butylphenyl) -5- (4'-biphenyl) -1,3,4-ox
adiazole] at a ratio of 30% by weight, and further doped with an iridium complex (Ir (ppy) 3), which is a triplet light emitting material, at a ratio of 1 mol%, and dissolved in toluene to a concentration of 20 mg / ml. Was. This solution was spin-coated to form a 100 nm film on a PEDOT-formed ITO substrate.
Vacuum drying was performed at 50 ° C. for 1 hour to obtain a light emitting layer.

Next, the substrate was fixed in a vacuum device, the pressure in the tank was reduced to 1 × 10 ⁻⁴ Pa or less, and then LiF was
m, and then Al was deposited to a thickness of 100 nm to form a cathode for an electron injection electrode and an auxiliary electrode.

Finally, glass sealing was performed to obtain an organic EL display device.

When an electric field was applied to this device using ITO as a positive electrode and Al as a negative electrode, a luminance of 2000 cd / m ² was obtained at a current density of 10 mA / cm ² . Maximum current efficiency is 2
3 cd / A and the maximum luminance reached 25000 cd / m ² .

<Example 2> PV was used as the hole transporting material.
Polyvinylyphenylamine [Polyviny
An organic EL device was prepared in the same manner as in Example 1 except that [ltriphenylamine] was used.

In this element, a current density of 10 mA / cm ²
A luminance of 500 cd / m ² was obtained. Maximum current efficiency is 15c
d / A and the maximum luminance reached 17000 cd / m ² .

<Comparative Example 1> The same procedure as in Example 1 was performed up to the formation of PEDOT.

Ir (ppy) 3 was added to π-conjugated polymer poly (9,9-dioctylfluorene) [Poly (9,9-diocthylfluorene)] so as to have a concentration of 1 mol%, and added to a chloroform solution. Dissolved. Using this solution, PEDOT
100 on the ITO substrate on which
nm was formed.

Next, the substrate was fixed in a vacuum device, and the pressure in the layer was reduced to 1 × 10 ⁻⁴ Pa or less.
m, and then Al was deposited to a thickness of 100 nm to form a cathode for an electron injection electrode and an auxiliary electrode.

Finally, glass sealing was performed to obtain an organic EL display device.

In this device, although light emission from Ir (ppy) 3 can be confirmed, poly (9,9-dioctylfluorene)
Light emission from the exciplex with [Poly (9,9-diocthylfluorene)] became dominant. For this reason, only a luminance of 100 cd / m ² was obtained at a current density of 10 mA / cm ² , and the maximum luminance was a low characteristic of 2000 cd / m ² .

<Comparative Example 2> The same procedure as in Example 1 was performed up to the formation of PEDOT.

As the light emitting layer, poly (2-methoxy, 5-
(2′-ethyl-hexaoxy) -1,4-phenylenevinylene) [Poly (2-methoxy, 5- (2′-ethyl-hexoxy) -1,4
-phenylenevinylene (MEH-PPV)], and Ir (ppy) 3 was added at a concentration of 1 mol%. Xylene was used for the solution, and a film was formed to a thickness of 100 nm by spin coating.

Next, the substrate was fixed in a vacuum device, and the pressure in the layer was reduced to 1 × 10 ⁻⁴ Pa or less.
m, and then Al was deposited to a thickness of 100 nm to form a cathode for an electron injection electrode and an auxiliary electrode.

Finally, glass sealing was performed to obtain an organic EL display device.

In this device, since the band gap of MEH-PPV was low, energy transfer did not occur to Ir (ppy) 3, and light emission from Ir (ppy) 3 could not be confirmed. Also,
The EL spectra were not from MEH-PPV,
Light was emitted from the exciplex of PV and Ir (ppy) 3. Therefore, at a current density of 10 mA / cm ² , 40 cd / m ²
, And the highest luminance was as low as 250 cd / m ² .

Comparative Example 3 An EL device was prepared in the same manner as in Example 1, except that Coumaline 6 was used as a doping material instead of Ir (ppy) 3.

The characteristics of this device are such that a luminance of only 60 cd / m ² can be obtained at a current density of 10 mA / cm ² and a maximum luminance of 30 cd / m ^2.
The characteristics were as low as 00 cd / m ^2, which was 1/30 or less as compared with the device using Ir (ppy) 3.

[0109]

As described above, according to the present invention, by doping a triplet light emitting material into a polymer material, particularly a non-conjugated polymer, reliability such as thermal stability and high reliability in a high brightness region can be obtained. It is possible to realize an organic EL element that can simultaneously increase the efficiency.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a basic structure of an organic EL device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Hole injection electrode (positive electrode) 3 Electrode interface modification layer 4 Light emitting layer 5 Electron injection electrode (negative electrode)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3K007 AB02 AB03 AB14 CA01 CB01 DA01 DB03 DC00 EB00 5F041 CA45 CA47 CA91

Claims (6)

[Claims] 1. An electron injection electrode, an electron injection electrode, and a light emitting layer including an organic host material and a dopant between these electrodes, wherein the organic material is a non-conjugated polymer material, and the dopant is a triple layer. Is an organometallic complex capable of emitting phosphorescence from the term state, at least in the Mendeleev periodic table.
An organic EL device containing a metal ion belonging to Group VIII. 2. The organic EL device according to claim 1, wherein the host material has a carbazole group. 3. The organic EL device according to claim 1, wherein the organic host material has a hole transporting property. 4. The organic EL device according to claim 1, wherein said metal ion is iridium or platinum. 5. The organic EL device according to claim 1, wherein the energy gap (Eg) of the organic host material is 2.4 eV or more. 6. The organic EL according to claim 1, further comprising an electrode interface modification layer between the light emitting layer and one of the electrodes.
element.