JP2003138251A - Organic luminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic luminescent device which emits a high luminosity of light with a very high efficiency and has durability. SOLUTION: The organic luminescent device comprises at least a pair of electrodes consisting of an anode and a cathode and layers containing one or more organic compounds held between the pair of the electrodes, wherein at least one of the layers contains at least one of a tetraarylmethane compound represented by formula [I] (wherein Ar1 -Ar4 are same or each independently a substituted or unsubstituted aryl group, a heterocyclic group, a fused polycyclic aromatic group or a fused polycyclic heterocyclic group) and a tetraarylsilane compound represented by formula II (wherein Ar5 -Ar8 are same or each independently a substituted or unsubstituted aryl group, an aryloxy group, a heterocyclic group, a fused polycyclic aromatic group or a fused polycyclic heterocyclic group).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting device, and more particularly to a device that emits light by applying an electric field to a thin film containing an organic compound.

[0002]

2. Description of the Related Art In an organic light emitting device, a thin film containing a fluorescent organic compound is sandwiched between an anode and a cathode and electrons and holes are injected from each electrode to excite excitons of the fluorescent compound. It is an element that uses the light emitted when the excitons return to the ground state.

1987 Research by Kodak Company (Appl.
Phys. Lett. 51, 913 (1987)), an anode is made of ITO, a cathode is made of a magnesium-silver alloy, an aluminum quinolinol complex is used as an electron transporting material and a light emitting material, and a triphenylamine derivative is used as a hole transporting material. A two-layer device with an applied voltage of about 10 V is 1000 cd / m ²
Some light emission has been reported. Related patents include US Pat. No. 4,539,507 and US Pat. No. 4,720,4.
32, US Pat. No. 4,885,211 and the like.

Further, it is possible to emit light from ultraviolet to infrared by changing the kind of the fluorescent organic compound, and recently, various compounds have been actively researched. For example, US Pat. No. 5,151,629, US Pat.
9,783, US Pat. No. 5,382,477, JP-A-2-247278, JP-A-3-255190, JP-A-5-202356, JP-A-9-202.
No. 878, Japanese Patent Laid-Open No. 9-227576, and the like.

Further, in addition to the organic light emitting device using the low molecular weight material as described above, an organic light emitting device using a conjugated polymer is also available at the group of Cambridge University (Nature,
347, 539 (1990)).
In this report, light emission is confirmed in a single layer by depositing polyphenylene vinylene (PPV) in a coating system.
Related patents for organic light emitting devices using conjugated polymers include US Pat. No. 5,247,190 and US Pat.
4,878, US Pat. No. 5,672,678, JP-A-4-145192, JP-A-5-247460 and the like.

As described above, the recent progress in organic light-emitting devices is remarkable, and the features thereof are that it is possible to realize a light-emitting device with high luminance, diversity of emission wavelength, high-speed response, thinness and light weight at a low applied voltage. It suggests the possibility of a wide range of applications.

However, under the present circumstances, further higher brightness light output or higher conversion efficiency is required. Further, there are still many problems in terms of durability such as deterioration with time due to long-term use and deterioration due to atmospheric gas containing oxygen or moisture. Further, in consideration of application to a full-color display or the like, it is necessary to emit light of blue, green, and red with good color purity, but these problems are still insufficient.

Aromatic compounds and condensed polycyclic aromatic compounds have been extensively studied as fluorescent organic compounds for use in electron transport layers and light emitting layers. For example, JP-A-4-6807
6, JP-A-5-32966, JP-A-6-2.
28552, JP-A-6-240244, JP-A-7-109454, and JP-A-8-31142.
JP, JP-A-9-241629, JP, 2000
JP-A-26334, JP-A-2000-268964 and the like are mentioned, but those which can sufficiently satisfy the emission brightness and durability have not been obtained.

Further, the spiro compound has a unique three-dimensional structure and has attracted attention as an organic functional material due to its unique material properties (J. Am. Chem. Soc., 11) .
0 , 5687, 1988). Although there is an example in which a spiro compound is used in an organic light emitting device (Japanese Patent Laid-Open No. 7-278537), sufficient light emitting characteristics as an electron transport layer or a light emitting layer are not obtained.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic light emitting device which uses a tetraarylmethane compound or a tetraarylsilane compound and has an extremely high efficiency and high brightness light output.

Another object of the present invention is to provide an organic light emitting device having extremely high durability.

Another object of the present invention is to provide an organic light emitting device which is easy to manufacture and can be manufactured at a relatively low cost.

[0013]

The organic light emitting device of the present invention is an organic light emitting device having at least a pair of electrodes consisting of an anode and a cathode and a layer containing one or more organic compounds sandwiched between the pair of electrodes. In the device, at least one of the layers containing the organic compound contains at least one tetraarylmethane compound represented by the following general formula [I].

[0014]

[Chemical 11]

(In the formula, Ar _{1 to} Ar ₄ are substituted or unsubstituted aryl groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted fused polycyclic aromatic groups, substituted or unsubstituted fused polycyclic groups. Represents a ring heterocyclic group. Ar _{1 to} Ar ₄ may be the same or different.) In the above light emitting device, the tetraarylmethane compound represented by the general formula [I] is represented by the following general formula: It is preferably represented by [II], and more preferably represented by the following general formula [III].

[0016]

[Chemical 12]

(Wherein R _{1 to} R ₅ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). Represents a cyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a cyano group, a trifluoromethyl group or a halogen atom, provided that at least one of R _{1 to} R ₅ Is a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocycle Represents a group, and R _{1 to} R ₅ may be the same or different.)

[0018]

[Chemical 13]

(In the formula, R _{6 to} R ₁₀ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group. Represents a cyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a cyano group, a trifluoromethyl group or a halogen atom, and R _{6 to} R ₁₀ are the same. Or they may be different.)

The tetraarylmethane compound represented by the above general formula [I] is preferably represented by the following general formula [IV], and more preferably represented by the following general formula [V].

[0021]

[Chemical 14]

(In the formula, R _{11 to} R ₁₃ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group. Represents a cyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that R _{11 to} R _{11 At} least one of ₁₃ is a substituted or unsubstituted aryl group,
A substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group,
It represents a substituted or unsubstituted fused polycyclic heterocyclic group. R ₁₁
~ R ₁₃ may be the same or different. )

[0023]

[Chemical 15]

(Wherein R _{14 to} R ₁₈ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). ring group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, .R ₁₄ to R ₁₈ represents a trifluoromethyl group or a halogen atom , May be the same or different.)

Further, the organic light emitting device of the present invention is an organic light emitting device having at least a pair of electrodes consisting of an anode and a cathode, and a layer containing one or a plurality of organic compounds sandwiched between the pair of electrodes. At least one of the layers containing an organic compound contains at least one tetraarylsilane compound represented by the following general formula [VI].

[0026]

[Chemical 16]

(Wherein Ar _{5 to} Ar ₈ are a substituted or unsubstituted aryl group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group). And a substituted or unsubstituted fused polycyclic heterocyclic group, Ar _{5 to} Ar ₈ may be the same or different.)

In the above light emitting device, the above general formula [V
The tetraarylsilane compound represented by the formula [I] is preferably represented by the following general formula [VII], and more preferably represented by the following general formula [VIII].

[0029]

[Chemical 17]

(Wherein R _{19 to} R ₂₃ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). Represents a cyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that R _{19 to} R _At least one of ₂₃ is a substituted or unsubstituted aryl group,
A substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group,
It represents a substituted or unsubstituted fused polycyclic heterocyclic group. R ₁₉
~ R ₂₃ may be the same or different. )

[0031]

[Chemical 18]

(Wherein R _{24 to} R ₂₈ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). ring group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, .R ₂₄ to R ₂₈ represents a trifluoromethyl group or a halogen atom , May be the same or different.)

The tetraarylsilane compound represented by the general formula [VI] is preferably represented by the following general formula [IX], more preferably the following general formula [X].

[0034]

[Chemical 19]

(Wherein R _{29 to} R ₃₁ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). Represents a cyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that R _{29 to} R _At least one of ₃₁ is a substituted or unsubstituted aryl group,
A substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group,
It represents a substituted or unsubstituted fused polycyclic heterocyclic group. R ₂₉
~ R ₃₁ may be the same or different. )

[0036]

[Chemical 20]

(Wherein R _{32 to} R ₃₆ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group). ring group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, .R ₃₂ to R ₃₆ represents a trifluoromethyl group or a halogen atom , May be the same or different.)

Further, in the light emitting device of the present invention, at least the electron transport layer or the light emitting layer is represented by the above general formula [I].
It is preferable to contain at least one of the tetraarylmethane compound or the tetraarylsilane compound represented by [X].

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.

First, the above general formula [I] to be used in the present invention is described.
The tetraarylmethane compound and tetraarylsilane compound represented by [X] will be described.

Specific examples of the substituents in the above general formulas [I] to [X] are shown below.

Examples of the alkyl group include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, ter-butyl group and octyl group.

Examples of the aralkyl group include a benzyl group and a phenethyl group.

Examples of the aryl group include a phenyl group, a biphenyl group, a terphenyl group and a cyclopentadienyl group.

Examples of the heterocyclic group include thienyl group, furyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group, thiazolyl group, isothiazolyl group, thiadiazolyl group, pyrrolyl group, pyridyl group, pyridazyl group, pyrimidyl group, aziridyl group, triazyl group. , Terthienyl group, terpyrrolyl group and the like.

As the condensed polycyclic aromatic group, a naphthyl group,
Examples thereof include anthranyl group, phenanthryl group, pyrenyl group, tetracenyl group, pentacenyl group, fluorenyl group and fluoranthenyl group.

As the condensed polycyclic heterocyclic group, a quinolyl group,
Examples thereof include a carbazolyl group, an acridyl group, and a phenanthryl group.

Examples of the substituted amino group include a dimethylamino group, a diethylamino group, a dibenzylamino group, a diphenylamino group, a ditolylamino group, a dianisolylamino group and the like.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine.

Examples of the substituent which the above-mentioned substituent may have include an alkyl group such as a methyl group, an ethyl group and a propyl group, an aralkyl group such as a benzyl group and a phenethyl group, a phenyl group, a biphenyl group and a terphenyl group. Aryl group, styryl group, thienyl group, furyl group, oxazolyl group, isoxazolyl group, oxadiazolyl group, thiazolyl group, isothiazolyl group, thiadiazolyl group, pyrrolyl group, pyridyl group, pyridazyl group, pyrimidyl group, aziridyl group, triazyl group, tertienyl Group, heterocyclic group such as terpyrrolyl group, naphthyl group, anthranilyl group, phenanthryl group, pyrenyl group, tetracenyl group,
Condensed polycyclic aromatic groups such as pentacenyl group, fluorenyl group, fluoranthenyl group, condensed polycyclic heterocyclic groups such as quinolyl group, carbazolyl group, acridyl group, phenanthryl group, dimethylamino group, diethylamino group, dibenzylamino group , An amino group such as a diphenylamino group, a ditolylamino group, and a dianisolylamino group, an methoxyl group, an ethoxyl group, a propoxyl group, an alkoxyl group such as a phenoxyl group, a cyano group, a trifluoromethyl group, fluorine, chlorine, bromine, Halogen atoms such as iodine,
Examples thereof include a nitro group.

Next, typical examples of the compounds (condensed polycyclic compounds) represented by the general formulas [I] to [X] of the present invention are shown below, but the present invention is not limited thereto.

[0052]

[Chemical 21]

[0053]

[Chemical formula 22]

[0054]

[Chemical formula 23]

[0055]

[Chemical formula 24]

[0056]

[Chemical 25]

[0057]

[Chemical formula 26]

[0058]

[Chemical 27]

[0059]

[Chemical 28]

[0060]

[Chemical 29]

The compounds represented by the general formulas [I] to [X] of the present invention can be synthesized by a generally known method, for example, Tetrahedron Letter, 38, 1.
485, 1997 and Journal of Mater
ials Chemistry, 3,991,1993
It can be obtained by the synthetic method described in.

The compounds represented by the general formulas [I] to [X] of the present invention are more excellent in electron transporting property, light emitting property and durability than conventional compounds, and include organic compounds of organic light emitting devices. It is useful as a layer, especially as an electron transport layer and a light emitting layer, and a layer formed by a vacuum vapor deposition method, a solution coating method or the like is less likely to be crystallized and has excellent stability over time.

Next, the organic light emitting device of the present invention will be described in detail.

The organic light-emitting device of the present invention is an organic light-emitting device having at least a pair of electrodes consisting of an anode and a cathode and a layer containing one or a plurality of organic compounds sandwiched between the pair of electrodes. At least one layer containing the compound contains at least one compound represented by the general formulas [I] to [X].

In the organic light emitting device of the present invention, it is preferable that at least the electron transport layer or the light emitting layer of the layer containing the organic compound contains at least one of the tetraarylmethane compound and the tetraarylsilane compound.

In the organic light emitting device of the present invention, the compounds represented by the above general formulas [I] to [X] are formed between the anode and the cathode by a vacuum deposition method or a solution coating method. The thickness of the organic layer is thinner than 10 μm, preferably 0.5 μm or less, and more preferably 0.01 to 0.5 μm.

1 to 6 show preferred examples of the organic light emitting device of the present invention.

FIG. 1 is a sectional view showing an example of the organic light emitting device of the present invention. FIG. 1 shows a structure in which an anode 2, a light emitting layer 3 and a cathode 4 are sequentially provided on a substrate 1. The light emitting device used here is useful when it has a single hole transporting ability, an electron transporting ability and a light emitting ability by itself, or when a compound having each characteristic is mixed and used.

FIG. 2 is a sectional view showing another example of the organic light emitting device of the present invention. In FIG. 2, an anode 2, a hole transport layer 5, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. In this case, when the light-emitting substance has a hole-transporting property, an electron-transporting property, or both, is used for each layer, and is used in combination with a mere hole-transporting substance or electron-transporting substance having no light-emitting property. Useful for. In this case, the light emitting layer is composed of either the hole transport layer 5 or the electron transport layer 6.

FIG. 3 is a sectional view showing another example of the organic light emitting device of the present invention. FIG. 3 shows a structure in which an anode 2, a hole transport layer 5, a light emitting layer 3, an electron transport layer 6 and a cathode 4 are sequentially provided on a substrate 1. This separates the functions of carrier transport and light emission, and is used in combination with a compound having hole transporting property, electron transporting property, and light emitting property in a timely manner to greatly increase the degree of freedom in material selection and to increase the emission wavelength. Since various compounds having different colors can be used, it is possible to diversify the emission hue. Further, it becomes possible to effectively confine each carrier or exciton in the central light emitting layer 3 to improve the light emitting efficiency.

FIG. 4 is a sectional view showing another example of the organic light emitting device of the present invention. FIG. 4 shows a structure in which the hole injection layer 7 is inserted on the side of the anode 2 as compared with FIG. 3, which is effective in improving the adhesion between the anode 2 and the hole transport layer 5 or improving the hole injection property, and is effective in lowering the voltage. Target.

5 and 6 are sectional views showing other examples of the organic light emitting device of the present invention. 5 and 6 show
In contrast to FIGS. 3 and 4, a layer that prevents holes or excitons (excitons) from escaping to the cathode 4 side (hole /
The exciton blocking layer 8) is inserted between the light emitting layer 3 and the electron transport layer 6. By using a compound having a very high ionization potential as the hole / exciton blocking layer 8, the structure is effective for improving the luminous efficiency.

However, FIGS. 1 to 6 show only a very basic device structure, and the structure of the organic light emitting device using the compound of the present invention is not limited to these. For example,
Various layer configurations can be adopted such as providing an insulating layer at the interface between the electrode and the organic layer, providing an adhesive layer or an interference layer, and forming the hole transport layer from two layers having different ionization potentials.

General formulas [I] to [X] used in the present invention
The compound represented by has an electron transporting property,
It is a compound having excellent light emitting property and durability, and is shown in FIGS.
Any of the above can be used.

In particular, the organic layer using the compounds represented by the general formulas [I] to [X] is useful as the electron transport layer and the light emitting layer, and the layer formed by the vacuum vapor deposition method or the solution coating method is Excellent aging stability with less crystallization.

The present invention uses the compounds represented by the general formulas [I] to [X] as the constituent components of the electron transport layer and the light emitting layer. If necessary, a compound or an electron transporting compound may be used together.

Examples of these compounds will be given below.

[0078]

[Chemical 30]

[0079]

[Chemical 31]

[0080]

[Chemical 32]

[0081]

[Chemical 33]

[0082]

[Chemical 34]

[0083]

[Chemical 35]

In the organic light emitting device of the present invention, the layer containing the compounds represented by the general formulas [I] to [X] and the layer containing another organic compound are generally formed by a vacuum vapor deposition method or by a suitable solvent. It is dissolved and a thin film is formed by a coating method. In particular, when the film is formed by the coating method, the film can be formed by combining with an appropriate binder resin.

The binder resin can be selected from a wide range of binder resins such as polyvinyl carbazole resin,
Polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, acrylic resin, methacrylic resin, butyral resin, polyvinyl acetal resin,
Examples thereof include diallyl phthalate resin, phenol resin, epoxy resin, silicone resin, polysulfone resin, and urea resin, but are not limited thereto. Further, these may be used alone or as a copolymer polymer, or one or more kinds thereof may be mixed.

As the anode material, those having a work function as large as possible are preferable. A metal oxide such as ITO) or zinc indium oxide can be used. In addition, conductive polymers such as polyaniline, polypyrrole, polythiophene, and polyphenylene sulfide can also be used. These electrode substances may be used alone or in combination of two or more.

On the other hand, as the cathode material, one having a small work function is preferable, and lithium, sodium, potassium, calcium, magnesium, aluminum, indium, silver,
It can be used as a simple metal or a plurality of alloys of lead, tin, chromium and the like. It is also possible to use a metal oxide such as indium tin oxide (ITO). The cathode may have a single layer structure or a multilayer structure.

The substrate used in the present invention is not particularly limited, but an opaque substrate such as a metal substrate or a ceramic substrate, or a transparent substrate such as glass, quartz or a plastic sheet is used. Further, it is also possible to control the emitted light by using a color filter film, a fluorescent color conversion filter film, a dielectric reflection film or the like on the substrate.

A protective layer or a sealing layer may be provided on the produced element for the purpose of preventing contact with oxygen, moisture or the like. Examples of the protective layer include an inorganic material film such as a diamond thin film, a metal oxide and a metal nitride, a polymer film such as a fluorine resin, polyparaxylene, polyethylene, a silicone resin and a polystyrene resin, and a photocurable resin. To be It is also possible to cover the glass, gas impermeable film, metal, etc., and package the element itself with a suitable sealing resin.

[0090]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1 An element having the structure shown in FIG. 2 was prepared.

On a glass substrate as the substrate 1, indium tin oxide (ITO) as the anode 2 was formed by sputtering 1
The film having a film thickness of 20 nm was used as a transparent conductive support substrate. This was sequentially ultrasonically washed with acetone and isopropyl alcohol (IPA), then washed by boiling with IPA and then dried. Furthermore, what was washed with UV / ozone was used as a transparent conductive support substrate.

A hole-transporting layer 5 was formed on a transparent conductive support substrate by spin-coating a chloroform solution of a compound represented by the following structural formula to a film thickness of 30 nm.

[0094]

[Chemical 36]

Further, Exemplified Compound No. The tetraarylmethane compound represented by 2 was formed into a film with a thickness of 50 nm by a vacuum evaporation method to form the electron transport layer 6. The degree of vacuum during vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.2 to 0.3 nm.
The film was formed under the condition of / sec.

Next, as the cathode 4, a vapor deposition material consisting of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the above organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When a DC voltage of 10 V was applied to the thus obtained device with the ITO electrode (anode 2) as the positive electrode and the Al-Li electrode (cathode 4) as the negative electrode, 8.7 mA / cm 2 was applied.
^A current was passed through the device at a current density of ² , and blue light emission was observed at a brightness of 1700 cd / m ² .

Further, the current density is 7.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
Initial brightness of 1200 cd / m ² to 100 after 100 hours
The luminance deterioration was as small as cd / m ² .

[Examples 2 to 10, Comparative Examples 1 to 5] Exemplified Compound No. A device was prepared in the same manner as in Example 1 except that the compounds shown in Table 1 (Comparatives 1 to 5 were compounds represented by the following structural formulas) were used instead of 2, and the same evaluation was performed. The results are shown in Table 1.

[0100]

[Chemical 37]

[0101]

[Table 1]

[Embodiment 11] An element having the structure shown in FIG. 3 was prepared.

As in Example 1, the hole transport layer 5 was formed on the transparent conductive support substrate.

Further, the exemplified compound No. The tetraarylmethane compound shown by 1 was formed into a film having a thickness of 20 nm by a vacuum evaporation method to form a light emitting layer 3. The degree of vacuum during vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.2 to 0.3 nm /
The film was formed under the condition of sec.

Further, aluminum trisquinolinol was formed into a film with a thickness of 40 nm by a vacuum evaporation method to form an electron transport layer 6.
Was formed. The degree of vacuum at the time of vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 to 0.3 nm / sec.

Next, as the cathode 4, a vapor deposition material made of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When an ITO electrode (anode 2) was used as a positive electrode and an Al-Li electrode (cathode 4) was used as a negative electrode and a DC voltage of 8 V was applied to the device thus obtained, 9.0 mA / cm ²
An electric current flowed through the device at a current density of, and blue light emission was observed at a brightness of 9,700 cd / m ² .

Further, the current density is 7.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
Initial brightness of 7500 cd / m ² to 100 after 100 hours
The luminance deterioration was as small as cd / m ² .

[Examples 12 to 20, Comparative Examples 6 to 10] Exemplified Compound No. A device was prepared in the same manner as in Example 11 except that the compounds shown in Table 2 were used instead of 1, and the same evaluation was performed. The results are shown in Table 2.

[0110]

[Table 2]

Example 21 An element having the structure shown in FIG. 3 was prepared.

On the transparent conductive support substrate similar to that of Example 1, a chloroform solution of a compound represented by the following structural formula was formed into a film having a thickness of 20 nm by a spin coating method to form a hole transport layer 5.

[0113]

[Chemical 38]

Further, the compound represented by the following structural formula and the exemplified compound No. A tetraarylmethane compound represented by 4 (weight ratio 1:50) was formed into a film having a thickness of 20 nm by a vacuum vapor deposition method to form a light emitting layer 3. The degree of vacuum during vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.2 to 0.3 nm /
The film was formed under the condition of sec.

[0115]

[Chemical Formula 39]

Further, aluminum trisquinolinol was formed into a film with a thickness of 40 nm by a vacuum evaporation method to form an electron transport layer 6.
Was formed. The degree of vacuum at the time of vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 to 0.3 nm / sec.

Next, as the cathode 4, a vapor deposition material composed of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the above organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When an ITO electrode (anode 2) was used as a positive electrode and an Al-Li electrode (cathode 4) was used as a negative electrode and a DC voltage of 8 V was applied to the device thus obtained, 8.8 mA / cm ²
Current flows through the device at a current density of 85,000 cd / m ²
A blue emission was observed at the brightness of.

Further, the current density is 5.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
Initial brightness of 39000 cd / m ² to 340 after 100 hours
The luminance deterioration was as small as 00 cd / m ² .

[Examples 22 to 30, Comparative Examples 11 to 15]
Exemplified compound No. A device was prepared in the same manner as in Example 21 except that the compounds shown in Table 3 were used instead of 4, and the same evaluation was performed. The results are shown in Table 3.

[0121]

[Table 3]

Example 31 An element having the structure shown in FIG. 5 was prepared.

On the same transparent conductive supporting substrate as in Example 1, the hole transport layer 5 was formed in the same manner as in Example 21.

Further, rubrene and aluminum trisquinolinol (weight ratio 1:20) were added by vacuum evaporation to 2
After forming the light emitting layer 3 with a film thickness of 0 nm, the exemplary compound No. A hole / exciton blocking layer 8 was formed by forming a film of a tetraarylmethane compound represented by 3 in a film thickness of 10 nm by a vacuum evaporation method. Further, aluminum trisquinolinol was formed into a film having a thickness of 40 nm by a vacuum vapor deposition method to form the electron transport layer 6. The degree of vacuum during vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.2 to 0.3 nm /
The film was formed under the condition of sec.

Next, as the cathode 4, a vapor deposition material made of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the above organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When a DC voltage of 10 V was applied to the element thus obtained, with the ITO electrode (anode 2) as the positive electrode and the Al-Li electrode (cathode 4) as the negative electrode, 9.3 mA / cm 2 was applied.
Current flows through the element at a ^second current density, 80000cd / m ²
Yellow-green luminescence was observed at the luminance of.

Further, the current density is 7.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
450 hours after initial brightness of 54000 cd / m ² 450
The luminance deterioration was as small as 00 cd / m ² .

[Examples 32 to 40, Comparative Examples 16 to 20]
Exemplified compound No. A device was prepared in the same manner as in Example 31 except that the compounds shown in Table 4 were used instead of 3, and the same evaluation was performed. The results are shown in Table 4.

[0129]

[Table 4]

Example 41 An element having the structure shown in FIG. 3 was prepared.

On the same transparent conductive supporting substrate as in Example 1, the hole transport layer 5 was formed in the same manner as in Example 21.

Further, the compound represented by the following structural formula and the exemplified compound No. A tetraarylmethane compound represented by 2 (weight ratio 1:50) was formed into a film having a thickness of 20 nm by a vacuum evaporation method to form a light emitting layer 3. The degree of vacuum during vapor deposition is 1.0 × 10 ⁻⁴ Pa, and the film formation rate is 0.2 to 0.3 nm /
The film was formed under the condition of sec.

[0133]

[Chemical 40]

Further, aluminum trisquinolinol was formed into a film with a thickness of 40 nm by a vacuum evaporation method to form an electron transport layer 6.
Was formed. The degree of vacuum at the time of vapor deposition was 1.0 × 10 ⁻⁴ Pa, and the film formation rate was 0.2 to 0.3 nm / sec.

Next, as the cathode 4, a vapor deposition material composed of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the above organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When an ITO electrode (anode 2) was used as a positive electrode and an Al-Li electrode (cathode 4) was used as a negative electrode and a direct current voltage of 8 V was applied to the device thus obtained, 7.5 mA / cm ²
Current flows through the device at a current density of 13000 cd / m ²
A green light emission was observed at the luminance of.

Further, the current density is set to 5.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
Initial brightness of 8800 cd / m ² to 100 after 100 hours
The luminance deterioration was as small as cd / m ² .

[Examples 42 to 50, Comparative Examples 21 to 25]
Exemplified compound No. A device was prepared in the same manner as in Example 41 except that the compounds shown in Table 5 were used instead of 2, and the same evaluation was performed. The results are shown in Table 5.

[0139]

[Table 5]

Example 51 An element having the structure shown in FIG. 1 was prepared.

On the transparent conductive support substrate similar to that of Example 1, Exemplified Compound No. A solution of 0.050 g of the tetraarylmethane compound represented by 1 and 1.00 g of poly-N-vinylcarbazole (weight average molecular weight = 63,000) in 80 ml of chloroform was spin-coated (rotational speed = 2000 rpm) at 120 nm. A film having a thickness of 3 was formed to form an organic layer (light emitting layer 3).

Next, as the cathode 4, a vapor deposition material composed of aluminum and lithium (lithium concentration 1 atom%) was used, and a thickness of 150 n was formed on the above organic layer by a vacuum vapor deposition method.
m metal layer film was formed. The degree of vacuum during vapor deposition is 1.0 x 1
The film was formed under the conditions of 0 ⁻⁴ Pa and the film forming rate of 1.0 to 1.2 nm / sec.

When a DC voltage of 10 V was applied to the device thus obtained, with the ITO electrode (anode 2) as the positive electrode and the Al-Li electrode (cathode 4) as the negative electrode, 7.7 mA / cm 2 was applied.
Current flows through the element at a ^second current density, a blue light emission was observed at a luminance of 2500 cd / m ^2.

Furthermore, the current density is set to 5.0 in a nitrogen atmosphere.
When the voltage was applied for 100 hours while keeping at mA / cm ² ,
100 hours after the initial brightness of 1900 cd / m ² 1750
The luminance deterioration was as small as cd / m ² .

[Examples 52 to 55, Comparative Examples 26 to 30]
Exemplified compound No. A device was prepared in the same manner as in Example 51 except that the compounds shown in Table 6 were used instead of 1, and the same evaluation was performed. The results are shown in Table 6.

[0146]

[Table 6]

[0147]

As described above, the general formula [I]
The organic light-emitting device using the compound represented by [X] can obtain high-luminance light emission at a low applied voltage and is excellent in durability.

In particular, the organic layer containing the condensed polycyclic compound of the present invention is excellent as an electron transport layer and also as a light emitting layer.

Further, the element can be formed by using the vacuum deposition or the casting method, and the element having a large area can be easily prepared at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an organic light emitting device according to the present invention.

FIG. 2 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

FIG. 3 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

FIG. 4 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

FIG. 5 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

FIG. 6 is a cross-sectional view showing another example of the organic light emitting device according to the present invention.

[Explanation of symbols]

1 substrate 2 anode 3 light emitting layer 4 cathode 5 hole transport layer 6 Electron transport layer 7 hole injection layer 8 holes / exciton blocking layer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 11/06 655 C09K 11/06 655 660 660 690 690 H05B 33/14 H05B 33/14 B 33/22 33 / 22 A // C07C 15/16 C07C 15/16 15/52 15/52 15/60 15/60 15/62 15/62 22/08 22/08 211/54 211/54 255/51 255/51 255 / 52 255/52 C07F 7/06 C07F 7/06 7/08 7/08 C 7/10 7/10 CPS TUV (72) Inventor Akito Saito 3-30-2 Shimomaruko, Ota-ku, Tokyo Issue Canon Inc. F-term (reference) 3K007 AB02 AB03 AB18 DB03 4H006 AA03 AB91 4H049 VN01 VP01 VQ07 VQ16 VQ60 VQ62 VQ70 VQ71 VR24 VR44 VU25

Claims (11)

[Claims] 1. An organic light emitting device comprising at least a pair of electrodes consisting of an anode and a cathode and a layer containing one or more organic compounds sandwiched between the pair of electrodes, wherein at least one layer containing the organic compound is at least one layer. Containing at least one tetraarylmethane compound represented by the following general formula [I]. [Chemical 1] (In the formula, Ar _{1 to} Ar ₄ are a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group. Represents a group, and Ar _{1 to} Ar ₄ may be the same or different.) 2. The organic light emitting device according to claim 1, wherein the tetraarylmethane compound represented by the general formula [I] is represented by the following general formula [II]. [Chemical 2] (In the formula, R _{1 to} R ₅ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, A substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a cyano group, a trifluoromethyl group or a halogen atom, provided that at least one of R _{1 to} R ₅ is It represents a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted fused polycyclic heterocyclic group. R _{1 to} R ₅ may be the same or different.) 3. The organic light emitting device according to claim 3, wherein the tetraarylmethane compound represented by the general formula [II] is represented by the following general formula [III]. [Chemical 3] (In the formula, R _{6 to} R ₁₀ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, Represents a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a cyano group, a trifluoromethyl group or a halogen atom, and R _{6 to} R ₁₀ may be the same or different. It may be.) 4. The organic light emitting device according to claim 1, wherein the tetraarylmethane compound represented by the general formula [I] is represented by the following general formula [IV]. [Chemical 4] (In the formula, R _{11 to} R ₁₃ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that at least R _{11 to} R ₁₃ are present. 1
One is a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group,
It represents a substituted or unsubstituted fused polycyclic aromatic group or a substituted or unsubstituted fused polycyclic heterocyclic group. R _{11 to} R ₁₃ may be the same or different. ) 5. The organic light emitting device according to claim 4, wherein the tetraarylmethane compound represented by the general formula [IV] is represented by the following general formula [V]. [Chemical 5] (In the formula, R _{14 to} R ₁₈ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, and R _{14 to} R ₁₈ are the same. It may or may not be.) 6. An organic light-emitting device comprising at least a pair of electrodes consisting of an anode and a cathode and a layer containing one or a plurality of organic compounds sandwiched between the pair of electrodes, wherein at least one layer containing the organic compound is at least one layer. Is the following general formula [V
[I] containing at least one tetraarylsilane compound. [Chemical 6] (In the formula, Ar _{5 to} Ar ₈ are substituted or unsubstituted aryl groups, substituted or unsubstituted aryloxy groups, substituted or unsubstituted heterocyclic groups, substituted or unsubstituted fused polycyclic aromatic groups, substituted Alternatively, it represents an unsubstituted fused polycyclic heterocyclic group. Ar _{5 to} Ar ₈ may be the same or different.) 7. The organic light emitting device according to claim 6, wherein the tetraarylsilane compound represented by the general formula [VI] is represented by the following general formula [VII]. [Chemical 7] (In the formula, R _{19 to} R ₂₃ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that at least R _{19 to} R ₂₃ are present. 1
One is a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group,
It represents a substituted or unsubstituted fused polycyclic aromatic group or a substituted or unsubstituted fused polycyclic heterocyclic group. R _{19 to} R ₂₃ may be the same or different. ) 8. The organic light emitting device according to claim 7, wherein the tetraarylsilane compound represented by the general formula [VII] is represented by the following general formula [XIII]. [Chemical 8] (In the formula, R _{24 to} R ₂₈ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, and R _{24 to} R ₂₈ are the same. It may or may not be.) 9. The organic light emitting device according to claim 6, wherein the tetraarylsilane compound represented by the general formula [VI] is represented by the following general formula [IX]. [Chemical 9] (In the formula, R _{29 to} R ₃₁ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted fused polycyclic aromatic group, a substituted or unsubstituted fused polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, provided that at least R _{29 to} R ₃₁ are present. 1
One is a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group,
It represents a substituted or unsubstituted fused polycyclic aromatic group or a substituted or unsubstituted fused polycyclic heterocyclic group. R _{29 to} R ₃₁ may be the same or different. ) 10. The organic light emitting device according to claim 9, wherein the tetraarylsilane compound represented by the general formula [IX] is represented by the following general formula [X]. [Chemical 10] (In the formula, R _{32 to} R ₃₆ are a hydrogen atom, an alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted styryl group, a substituted or unsubstituted heterocyclic group, It represents a substituted or unsubstituted condensed polycyclic aromatic group, a substituted or unsubstituted condensed polycyclic heterocyclic group, a substituted amino group, a cyano group, a trifluoromethyl group or a halogen atom, and R _{32 to} R ₃₆ are the same. It may or may not be.) 11. The electron transport layer or the light emitting layer at least contains at least one of the tetraarylmethane compounds or tetraarylsilane compounds represented by the general formulas [I] to [X]. ~ 1
0. The organic light emitting device according to 0.