JP2008084913A - Organic electroluminescence element, display device, and lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL element that is formed of two light emitting layers made of phosphorescent light emitting compound and has high efficiency and long service life. <P>SOLUTION: Two light emitting layers contain a phosphorescent light emitting compount represented by general formula (1), wherein R<SB>1</SB>is a substituent, Z is a non-metal atom group, n is an integer, B is C, N, O or S, M is metal of 8-10 group, X is C, N or O, L is an atom group forming a bidentate ligand, and m is an integer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element, a display device using the organic electroluminescence element, and an illumination apparatus.

  Conventionally, there is an electroluminescence display (ELD) as a light-emitting electronic display device. Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements). Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

  On the other hand, an organic EL device has a structure in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light-emitting layer and recombining them. The device emits light by utilizing the emission of light (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Therefore, it has a wide viewing angle, high visibility, and since it is a thin-film type completely solid element, it has attracted attention from the viewpoints of space saving and portability.

  For the development of organic EL elements for practical use in the future, organic EL elements that emit light efficiently and with high luminance with lower power consumption are desired. For example, stilbene derivatives, distyrylarylene derivatives or A technique for doping a trisstyrylarylene derivative with a small amount of a phosphor to improve emission luminance and extend the lifetime of the device (see, for example, Patent Document 1), and using 8-hydroxyquinoline aluminum complex as a host compound. A device having an organic light emitting layer doped with a trace amount of a phosphor (see, for example, Patent Document 2), a device having an organic light emitting layer doped with a quinacridone dye as a host compound using 8-hydroxyquinoline aluminum complex ( For example, see Patent Document 3).

  In the technique disclosed in the above-mentioned patent document, when the emission from the excited singlet is used, the generation ratio of the singlet exciton and the triplet exciton is 1: 3, so the generation probability of the luminescent excited species is 25%. Since the light extraction efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University has reported on organic EL devices that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1), research on materials that exhibit phosphorescence at room temperature has become active. (See, for example, Non-Patent Document 2). When excited triplets are used, the upper limit of internal quantum efficiency is 100%, so in principle the luminous efficiency is four times that of excited singlets, and the performance is almost the same as that of cold cathode tubes. It can be applied to and attracts attention. For example, many compounds have been studied for synthesis centering on heavy metal complexes such as iridium complexes (see, for example, Non-Patent Document 3).

Further, studies using tris (2-phenylpyridine) iridium as a dopant have been made (for example, see Non-Patent Document 2). In addition, L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) (see, for example, Non-Patent Document 4) as a dopant, and tris (2- (p-tolyl) pyridine) iridium (as a dopant) Examination using Ir (ptpy) ₃ ), tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ), Ir (bzq) ₂ ClP (Bu) ₃ (for example, see Non-Patent Document 5). Studies using iridium complexes using phenylpyrazole as a ligand have been conducted (for example, see Patent Document 4).

  By the way, for example, in a single light emitting layer configuration of an imidazole-based phosphorescent dopant and a host, the carrier balance is adjusted between the dopant and the host, and it is rare that light is emitted at the center of the light emitting layer. Alternatively, the recombination region is biased to the interface on the electron transport side, energy transfer occurs to the hole transport layer or the electron transport layer having a small band gap, leading to a decrease in efficiency.

  In order to prevent energy transfer from the light emitting layer, for example, a material having a wider band gap than that of the light emitting layer needs to be used as a carrier blocking layer. However, durability is also required. There is no carrier blocking layer material having a large band gap and good durability so that blue can be efficiently emitted in the material constituting the element (a material having a large band gap is generally poor in durability).

  On the other hand, if the light emitting layer has two types of hosts, the carrier balance is improved, the recombination region can be moved away from the interface with the adjacent layer, energy transfer to the adjacent layer can be suppressed, and the carrier Since the burden on the blocking layer can be suppressed, high efficiency and long life are achieved.

For example, in a green light emitting material, a hole transporting host 4-4 ′, 4 ″ -tri (N-carbazolyl) triphenylamine (TCTA) and an electron transporting host 4,7-diphenyl-1,10-phenanthroline (BPhen) A two-layer light emitting layer doped with Ir (ppy) ₃ is known (see Non-Patent Document 6).

However, in the blue light emitting material having a wide band gap, the above-mentioned light emitting material with high efficiency and long life is not known, and there is a demand for a light emitting material that can emit blue light efficiently and has good durability. It was.
Japanese Patent No. 3093796 Japanese Unexamined Patent Publication No. 63-264692 JP-A-3-255190 International Publication No. 2004/085450 Pamphlet M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) M.M. E. Thompson et al. , The 10th International Works on Organic and Organic Electroluminescence (EL'00, Hamamatsu) Moon-Jae Youn. 0 g, Tsutsuo Tsutsui et al. , The 10th International Works on Organic and Organic Electroluminescence (EL'00, Hamamatsu) X. Zhou et al. , Appl. Phys. Lett. , Vol. 81, 4070-4072 (2002)

  An object of the present invention is to obtain a high-efficiency, long-life organic EL element having a two-layer structure of a light-emitting layer using a phosphorescent compound.

  The above object of the present invention is achieved by the following means.

  1. In an organic electroluminescence device having at least two light-emitting layers containing a phosphorescent compound represented by the following general formula (1), the host and the second light emission constituting the light-emitting layer A as the first light-emitting layer An organic electroluminescence device characterized in that a host constituting the light emitting layer B which is a layer is different.

[Wherein, R ₁ represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. n1 represents the integer of 0-5. B _{1 to} B ₅ represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and at least one of B _{1 to} B ₅ represents a nitrogen atom. M ₁ represents a group 8 to group 10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents an atomic group which forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. ]
2. 2. The electroluminescent device as described in 1 above, wherein in the general formula (1), the nitrogen-containing heterocycle formed by B _{1 to} B ₅ is an imidazole ring.

  3. 2. The organic electroluminescence device according to 1 above, wherein the general formula (1) is represented by the following general formula (2).

[In formula, R < ₁ >, R < ₂ >, R < ₃ > represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. n1 represents the integer of 0-5. M ₁ represents a group 8 to group 10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents an atomic group which forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. ]
4). 4. The organic electroluminescence device according to 3 above, wherein in the general formula (2), the substituent represented by R ₂ is represented by the following general formula (3).

[Wherein R ₄ represents a substituent having a steric parameter value (Es value) of −0.5 or less. R ₅ represents a substituent, and n5 represents an integer of 0 to 4. In the formula, * indicates a bonding position. ]
5. 5. The organic electroluminescent element according to any one of 1 to 4, wherein the phosphorescent compound represented by the general formula (1) has a phosphorescence wavelength of less than 480 nm.

  6). The phosphorescent compound represented by the general formula (1) contained in the light emitting layer A and the phosphorescent compound represented by the general formula (1) contained in the light emitting layer B are the same compound. The organic electroluminescent element according to any one of 1 to 5 above.

  7. 7. The organic electroluminescent element according to any one of 1 to 6, wherein the light emitting layer A and the light emitting layer B are adjacent to each other.

  8). 8. The organic electroluminescence device according to any one of 1 to 7, wherein at least one light emitting layer contains a carbazole derivative.

  9. 8. The organic electroluminescence element according to any one of 1 to 7, wherein at least one light emitting layer contains a furan derivative.

  10. 8. The organic electroluminescence device according to any one of 1 to 7, wherein at least one light emitting layer contains an azacarbazole derivative.

  11. 11. An illumination device comprising the organic electroluminescence element according to any one of 1 to 10 above.

  12 11. A display device comprising the organic electroluminescence element according to any one of 1 to 10 above.

  According to the present invention, a highly efficient and long-life organic EL device using a phosphorescent compound can be obtained.

  The best mode for carrying out the present invention will be described below.

  The present invention is an organic electroluminescence (EL) device having at least two light-emitting layers containing the phosphorescent compound represented by the general formula (1), wherein the light-emitting layer A is a first light-emitting layer. The organic electroluminescence element is characterized in that the host constituting the light emitting layer B is different from the host constituting the second light emitting layer.

  Since the light emitting layer has a two-layer configuration with two types of host, carrier balance is improved, the recombination region can be moved away from the interface with the adjacent layer, and energy transfer to the adjacent layer can be suppressed, and carrier blocking is also possible. Since the burden on the layer can also be suppressed, the organic electroluminescence element has high efficiency and long life.

  In a single light-emitting layer including the dopant material represented by the general formula (1) and one type of host, in order to prevent energy transfer from the light-emitting layer to the adjacent layer, the band gap is further increased than that of the light-emitting layer. Although a wide material must be provided as the carrier blocking layer, due to its role, a considerable burden is imposed on the carrier blocking layer and the interface between the light emitting layer and the carrier blocking layer, and durability is required more than materials of other layers. In particular, a material constituting a blue light-emitting organic EL element is required to have a larger band gap than that of green or red light-emitting materials, and thus it is difficult to find a durable carrier blocking layer material (a material having a large band gap). Therefore, the light-emitting layer has a two-layer structure of two types of hosts.

  In the organic EL device according to the present invention, which contains the phosphorescent compound represented by the general formula (1) and has at least two light emitting layers containing different host compounds, light emission on the hole transport layer side The doping concentration of the phosphorescent compound in the layer (light emitting layer A) is preferably higher than the doping concentration of the light emitting layer (light emitting layer B) on the electron transport layer side. The dopant represented by the general formula (1) has a shallow HOMO and easily traps holes. In order to quickly transport holes injected from the hole transport layer from the interface into the light emitting layer, it is necessary to increase the doping concentration. However, if the doping concentration on the light emitting layer B side is also increased, the holes are transported to the electron transport side. As a result, the emission region is biased toward the electron transport side interface. In addition, the efficiency may decrease due to TT disappearance. If the doping concentration of the light emitting layer A is higher than the doping concentration of the light emitting layer B, the carrier balance is further improved, resulting in high efficiency and long life.

  Moreover, it is preferable that the light emitting layer A and the light emitting layer B are adjacent. In that case, each host compound may be mixed in the interface of the light emitting layer A and the light emitting layer B containing a different host compound. In that case, it is preferable that the mixing ratio has a gradient.

  In the present invention, it is preferable that at least one light emitting layer contains a carbazole derivative, a furan derivative, or an azacarbazole derivative as a host compound.

  Each host compound may be contained in either of the light emitting layers A and B as the light emitting layer on the hole transport layer side (light emitting layer A) and the light emitting layer on the electron transport layer side (light emitting layer B). May be combined. In that case, any order may be used, but light emitting layer A / light emitting layer B = carbazole derivative / furan derivative, carbazole derivative / azacarbazole derivative, furan derivative / azacarbazole derivative is preferable. Particularly preferred are carbazole derivatives / furan derivatives.

  Moreover, it is preferable to use the same compound as the phosphorescent compound represented by the general formula (1) contained in each of the light emitting layer A and the light emitting layer B.

  Hereinafter, the phosphorescent compound represented by the general formula (1) will be described in detail.

<< Phosphorescent Compound Represented by General Formula (1) >>
In the phosphorescent compound represented by the general formula (1) according to the present invention, examples of the substituent represented by R ₁ include an alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert- Butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (eg, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (eg, vinyl group, allyl group) Etc.), alkynyl group (for example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group Xylyl, naphthyl, anthryl, azulenyl, acenaphthenyl, fluorenyl, phenane Aryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, , 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, Thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group) One is replaced by a nitrogen atom), mushroom Salinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy group, ethoxy group, propyloxy) Group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.) , Alkylthio groups (for example, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio groups (for example, cyclopentylthio group, cyclohexylthio group, etc.), Ruthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (Eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octyl) Aminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group For example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy Groups (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide groups (for example, methylcarbonylamino group, ethylcarbonylamino group, Dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, Octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group) Cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, Ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group naphthylureido 2-pyridylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2- Pyridylsulfinyl group etc.), alkylsulfonyl group (eg methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group etc.), arylsulfonyl group or heteroarylsulfonyl group (eg , Phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino) Butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, Trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.).

  Of these substituents, preferred are an alkyl group and an aryl group.

  Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. Examples of the 5- to 7-membered ring formed by Z include a benzene ring, naphthalene ring, pyridine ring, pyrimidine ring, pyrrole ring, thiophene ring, pyrazole ring, imidazole ring, oxazole ring, and thiazole ring. Of these, a benzene ring is preferred.

B ₁ .about.B ₅ represents a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, at least one nitrogen atom. The aromatic nitrogen-containing heterocycle formed by these five atoms is preferably a monocycle. Examples include pyrrole ring, pyrazole ring, imidazole ring, triazole ring, tetrazole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, oxadiazole ring, and thiadiazole ring. Among these, a pyrazole ring and an imidazole ring are preferable, and an imidazole ring is more preferable. These rings may be further substituted with the above substituents. Preferable substituents are an alkyl group and an aryl group, and more preferably an aryl group.

L ₁ represents an atomic group that forms a bidentate ligand together with X ₁ and X ₂ . Specific examples of the bidentate ligand represented by X ₁ -L ₁ -X ₂ include, for example, substituted or unsubstituted phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, picolinic acid And acetylacetone.

  These groups may be further substituted with the above substituents.

  m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. Especially, the case where m2 is 0 is preferable.

  As the metal represented by M1, a transition metal element of Group 8 to Group 10 (also referred to simply as a transition metal) of the periodic table of elements is used. Among them, iridium and platinum are preferable, and iridium is more preferable.

  The phosphorescent compound represented by the general formula (1) of the present invention may or may not have a polymerizable group or a reactive group.

In the general formula (1), the nitrogen-containing heterocycle formed by B _{1 to} B ₅ is preferably an imidazole ring.

When the nitrogen-containing heterocycle formed by B _{1 to} B ₅ is an imidazole ring, the general formula (1) is more preferably represented by the general formula (2).

In the general formula _{(2), R 1, R} 2, R 3 represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. n1 represents the integer of 0-5. M ₁ represents a group 8 to group 10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents an atomic group which forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3.

In the general formula (2), the substituents represented by R ₁ , R ₂ and R ₃ have the same meaning as the substituents represented by R ₁ in the general formula (1). Z, M ₁ , X ₁ and X ₂ , L _{1 and the} like are also synonymous with those in the general formula (1). Moreover, m1 and m2 are also synonymous.

Further, the group represented by R ₂ in the general formula (2) is preferably an aromatic hydrocarbon ring group (aromatic carbocyclic group), more preferably a substituted aryl group, and the substituted aryl is represented by the following general formula (3). The group represented by these is preferable.

In the general formula (3), R ₄ represents a substituent having a steric parameter value (Es value) of −0.5 or less. R ₅ is the same as R _1, n5 represents an integer of 0-4. Note that * represents a bonding position.

  Here, the Es value is a steric parameter derived from chemical reactivity. The smaller this value, the more sterically bulky substituent can be said.

  Hereinafter, the Es value will be described. In general, in ester hydrolysis under acidic conditions, it is known that the influence of substituents on the progress of the reaction may only be considered as steric hindrance. The Es value is obtained by quantifying the steric hindrance.

For example, the Es value of the substituent X is expressed by the following chemical reaction formula: X—CH ₂ COOR _X + H ₂ O → X—CH ₂ COOH + R _X OH
The reaction rate constant kX for hydrolyzing an α-monosubstituted acetic acid ester derived from α-monosubstituted acetic acid in which one hydrogen atom of the methyl group of acetic acid is substituted with the substituent X represented by the formula And the following chemical reaction formula: CH ₃ COOR _Y + H ₂ O → CH ₃ COOH + R _Y OH
(R _X is the same as R _Y ), which is obtained from the reaction rate constant kH when the acetate corresponding to the α-monosubstituted acetate described above is hydrolyzed under acidic conditions by the following formula: .

Es = log (kX / kH)
The reaction rate decreases due to the steric hindrance of the substituent X, and as a result, kX <kH, so the Es value is usually negative. When the Es value is actually obtained, the above two reaction rate constants kX and kH are obtained and calculated by the above formula.

  Specific examples of Es values are given by Unger, S. et al. H. Hansch, C .; , Prog. Phys. Org. Chem. 12, 91 (1976). The specific numerical values are also described in “Structure-activity relationship of drugs” (Regional Chemistry Special Issue 122, Nankodo) and “American Chemical Society Reference Book, 'Exploring QSAR' p.81 Table 3-3”. There is. Next, a part is shown in Table 1.

  Here, it should be noted that the Es value as defined in this specification is not defined by defining that of a methyl group as 0, but by assuming that a hydrogen atom is 0, and an Es value where a methyl group is 0. Minus 1.24.

In the present invention, R ₄ represents a substituent having a steric parameter value (Es value) of −0.5 or less. Preferably it is -7.0 or more and -0.6 or less, Most preferably, it is -7.0 or more and -1.0 or less.

In the present invention, for example, when a keto-enol tautomer may exist in R ₄ , the keto moiety converts the Es value as an enol isomer. Even when other tautomerism exists, the Es value is converted by the same conversion method.

  Specific examples of the phosphorescent compound represented by the general formula (1) and the general formula (2) of the present invention are shown below, but the present invention is not limited to these.

  These metal complexes are described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and synthesis by applying methods such as references described in these documents. it can.

  The phosphorescent compound represented by the general formula (1) according to the present invention preferably has a phosphorescence wavelength of less than 480 nm.

<Phosphorescence wavelength>
In the present invention, the phosphorescence wavelength of the compound is the 0-0 band of the phosphorescence spectrum. The 0-0 band of the phosphorescence spectrum can be obtained by the following measurement method.

  That is, the compound to be measured is dissolved in methylene chloride that has been well deoxygenated, placed in a phosphorescence measurement cell, irradiated with excitation light at room temperature (25 ° C.), and the emission spectrum is measured.

  Moreover, about the compound which cannot be melt | dissolved in the said solvent type | system | group, you may use the arbitrary solvent which can melt | dissolve the compound.

  Next, the 0-0 band is determined. In the present invention, the emission maximum wavelength that appears on the shortest wavelength side in the phosphorescence spectrum chart obtained by the above-described measurement method is defined as the 0-0 band.

  If the phosphorescence spectrum is weak, noise and peaks can be separated and peak wavelengths can be read by performing a smoothing process. Note that a smoothing method such as Savitzky & Golay can be applied as the smoothing process.

(Host compound)
Next, the host compound used in the present invention will be described.

  In the present invention, the host compound is defined as a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.01 at room temperature (25 ° C.) among compounds contained in the light emitting layer.

  Specific examples of the luminescent host compound are described in the following documents. For example, Japanese Patent Application Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787 gazette, 2002-15871 gazette, 2002-334788 gazette, 2002-43056 gazette, 2002-334789 gazette, 2002-75645 gazette, 2002-338579 gazette. No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. 2002-302516, 2002-305083, 2002-305084, 2002-308837, 2000-21572, 2005-340123, 2004-234952, 2004-28881 gazette etc.

  Further, the host compound according to the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (evaporation polymerizable light emitting host). .

  In the present invention, it is preferable that at least one light emitting layer contains a carbazole derivative, a furan derivative, or an azacarbazole derivative as a host compound. Therefore, the light-emitting layer A and the light-emitting layer B preferably contain a carbazole derivative, a furan derivative, or an azacarbazole derivative as a host compound.

  The typical examples of the carbazole derivative used in the present invention are given below.

  Typical examples of furan derivatives are given below.

  Typical examples of azacarbazole derivatives are given below.

  Next, the constituent layers of the organic EL device of the present invention will be described in detail.

In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.
(I) Anode / light emitting layer A / light emitting layer B / cathode (ii) Anode / hole transport layer / light emitting layer A / light emitting layer B / cathode (iii) Anode / hole transport layer / light emitting layer A / light emitting layer B / Electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer A / light emitting layer B / hole blocking layer / electron transport layer / cathode (v) anode / hole injection layer / hole transport layer / light emission Layer A / light emitting layer B / hole blocking layer / electron transport layer / electron injection layer / cathode (vi) anode / hole injection layer / hole transport layer / light emitting layer A / mixing layer / light emitting layer B / electron transport layer / Electron injection layer / cathode << light emitting layer >>
In the present invention, the light emitting layer is a light emitting layer composed of at least two layers containing the phosphorescent compound represented by the general formula (1) as described above, and is a light emitting layer that is the first light emitting layer. The host constituting the layer A and the host constituting the light emitting layer B which is the second light emitting layer are different, but the light emitting layer A and the light emitting layer B are preferably adjacent to each other, preferably each It is preferable that the phosphorescence emission wavelength of the phosphorescence emission compound represented by the general formula (1) is 480 nm or less.

  The light emitting layer is a layer that emits light by recombination of electrons and holes injected from an electrode, an electron transport layer, a hole transport layer, or the like. In the present invention, the light emitting layer has at least two layers as described above. .

(Phosphorescent compound (also called phosphorescent dopant or phosphorescent compound))
The light emitting layer of the organic EL device of the present invention contains a phosphorescent compound (also referred to as a phosphorescent dopant or a phosphorescent compound) and a host compound. In the present invention, the compound represented by the general formula (1) or (2) described above is used as the sex compound.

  In the organic EL device of the present invention, a plurality of phosphorescent compounds represented by the general formula (1) or (2) can be used. By using a plurality of kinds, it becomes possible to mix different light emission, and thereby any light emission color can be obtained. White light emission is possible by adjusting the kind of phosphorescent dopant and the amount of doping, and can also be applied to illumination and backlight. Among the dopants represented by the general formula (1) or (2) of the present invention, typical examples of compounds capable of emitting white light in combination with those having a phosphorescence emission wavelength of 480 nm or less are given below.

  A plurality of known phosphorescent compounds may be used in combination with the compound of the present invention. By using a plurality of phosphorescent dopants, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent dopant and the amount of doping, and can also be applied to illumination and backlight.

  Specific examples of known phosphorescent compounds include compounds described in the following documents.

  WO 00/70655 pamphlet, JP 2002-280178, JP 2001-181616, JP 2002-280179, JP 2001-181617, JP 2002-280180, JP 2001-247859, JP 2002-299060, JP 2001-313178, JP 2002-302671, JP 2001-345183, JP 2002-324679, International Publication No. 02/15645 pamphlet, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-2002 A. No. 117978, JP 20 JP-A-2-338588, JP-A-2002-170684, JP-A-2002-352960, WO01 / 93642, JP-A-2002-50483, JP-A-2002-1000047, JP-A-2002. No. -173744, JP-A No. 2002-359082, JP-A No. 2002-17584, JP-A No. 2002-363552, JP-A No. 2002-184582, JP-A No. 2003-7469, JP-T-2002-525808. Gazette, JP2003-7471, JP2002-525833, JP2003-31366, JP2002-226495, JP2002-234894, JP2002-2335076 JP 2002-241751 A JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, JP 2002-343572, JP 2002-203678 gazette etc.

  The host compound has been described above. Hereinafter, constituent layers other than the light emitting layer that can be used in the organic EL device of the present invention will be described.

《Hole transport layer》
The hole transport layer includes a material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transport material is not particularly limited, and is conventionally used as a hole charge injection / transport material in an optical transmission material or a well-known material used for a hole injection layer or a hole transport layer of an EL element. Any one can be selected and used.

  The hole transport material has one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbenes Derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, particularly thiophene oligomers, and the like can be given.

  As the hole transport material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material. JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material described in a book (Applied Physics Letters 80 (2002), p. 139) can also be used. In the present invention, these materials are preferably used because a light-emitting element with higher efficiency can be obtained, and the hole transport material preferably has a high Tg.

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm.

  This hole transport layer may have a single layer structure composed of one or more of the above materials.

  Further, a hole transport layer having a high p property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use a hole transport layer having such a high p property because a device with lower power consumption can be produced.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided with a single layer or multiple layers.

  Conventionally, in the case of a single-layer electron transport layer and a plurality of layers, the following materials are used as the electron transport material (also serving as a hole blocking material) used for the electron transport layer adjacent to the cathode side with respect to the light emitting layer. Are known. Further, the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any material can be selected from conventionally known compounds. .

  Examples of materials used for this electron transport layer (hereinafter referred to as electron transport materials) include heterocyclic tetracarboxylic acid anhydrides such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, carbodiimides, Examples include fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, and oxadiazole derivatives. Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron withdrawing group can also be used as an electron transport material.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

Further, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum. , Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), and the like, and the central metal of these metal complexes is In, Mg, Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as the electron transport material. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC. A semiconductor can also be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 5 nm-about 5 micrometers, Preferably it is 5 nm-200 nm.

  The electron transport layer may have a single layer structure composed of one or more of the above materials.

  An impurity-doped electron transport layer having a high n property can also be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

  In the present invention, it is preferable to use an electron transport layer having such a high n property because an element with lower power consumption can be manufactured.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is a layer that is provided between the electrode and the organic layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its forefront of industrialization (issued on November 30, 1998 by NTS Corporation) 2 of Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The injection layer may be provided as necessary, and may be present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above.

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene. The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 to 5 μm, although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material having a function of transporting electrons but having a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking. Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

"anode"
As the anode according to the organic EL device of the present invention, an electrode having a work function (4 eV or more) metal, alloy, electrically conductive compound and a mixture thereof as an electrode material is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not required (100 μm or more) Degree), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. When light emission is extracted from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

"cathode"
On the other hand, as the cathode according to the present invention, a cathode having a work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function value than this, such as a magnesium / silver mixture, magnesium, from the viewpoint of electron injectability and durability against oxidation, etc. / Aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 1000 nm, preferably 50 nm to 200 nm. In order to transmit light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

《Support base》
The support substrate (hereinafter also referred to as a substrate, a substrate, a substrate, a support, etc.) according to the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc., and is transparent or opaque. It may be. In the case where light is extracted from the support base side, the support base is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support base is a resin film capable of giving flexibility to the organic EL element. Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones, Cycloolefin resins such as polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned. On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. Water vapor permeability measured by a method in accordance with JIS K 7129-1992 (25 ± 0.5 ° C., It is preferable that the relative humidity (90 ± 2)% RH) is a barrier film of 1 × 10 ⁻³ g / (m ² · 24 h) or less, and further measured by a method based on JIS K 7126-1987. The oxygen permeability is 1 × 10 ⁻³ ml / m ² · 24 h · atm or less, and the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is 1 × 10 ^−3. It is preferable that it is a high barrier film of g / (m ² · 24h) or less.

  As a material for forming a barrier film formed on the surface of the resin film in order to obtain a high barrier film, any material may be used as long as it has a function of suppressing intrusion of an element such as moisture or oxygen that causes deterioration of the element. Silicon, silicon dioxide, silicon nitride, or the like can be used. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

<Method for forming barrier film>
The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, the sputtering method, the reactive sputtering method, the molecular beam epitaxy method, the cluster ion beam method, the ion plating method, the plasma polymerization method, the atmospheric pressure plasma weighting. A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable. Examples of the opaque support base include metal plates / films such as aluminum and stainless steel, opaque resin substrates, ceramic substrates, and the like.

  The external extraction efficiency at room temperature of light emission of the organic EL device of the present invention is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100. In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor.

<Sealing>
Examples of the sealing means used for sealing the organic EL element of the present invention include a method of bonding a sealing member, an electrode, and a support base with an adhesive. The sealing member may be disposed so as to cover the display area of the organic EL element, and may be concave or flat. Moreover, transparency and electrical insulation are not particularly limited. Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.

  Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film has a water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by a method in accordance with JIS K 7129-1992, 1 × 10 ⁻³ g / (M ² · 24h) It is preferable that the film has a barrier property of not more than 1, and furthermore, the oxygen permeability measured by a method according to JIS K 7126-1987 is 1 × 10 ⁻³ ml / m ² · 24h ·. It is preferable that the film has a high barrier property with a water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) of 1 × 10 ⁻³ g / (m ² · 24 h) or less. .

  For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

  Specific examples of the adhesive include photocuring and thermosetting adhesives having a reactive vinyl group of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylate. be able to. Moreover, the heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned. In addition, since an organic EL element may deteriorate by heat processing, what can be adhesive-hardened from room temperature to 80 degreeC is preferable. A desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print it like screen printing.

  In addition, it is also preferable to coat the electrode and the organic layer on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and form an inorganic or organic layer in contact with the support substrate to form a sealing film. it can. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of the element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. it can. Furthermore, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials.

  The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used. In the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, or an inert liquid such as fluorinated hydrocarbon or silicon oil is injected in the gas phase and the liquid phase. Is preferred. A vacuum can also be used. Moreover, a hygroscopic compound can also be enclosed inside. Examples of the hygroscopic compound include metal oxides (eg, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide), sulfates (eg, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate, etc.). Metal halides (eg, calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide, etc.), perchloric acids (eg, barium perchlorate, In particular, anhydrous salts are preferably used in sulfates, metal halides and perchloric acids.

《Protective film, protective plate》
In order to increase the mechanical strength of the element, a protective film or a protective plate may be provided outside the sealing film or the sealing film on the side facing the support substrate with the organic layer interposed therebetween. In particular, when sealing is performed by the sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, etc. used for the sealing can be used, but the polymer film is light and thin. Is preferably used.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / cathode will be described.

  First, a thin film made of a desired electrode material, for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm, thereby producing an anode. To do. Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer, which is a device material, is formed thereon.

  As a method for forming a thin film containing this organic compound, there are a spin coat method, a cast method, an ink jet method, a vapor deposition method, a printing method, etc., but a uniform film is easily obtained and pinholes are not easily generated. From the point of view, a vacuum deposition method, a spin coating method, an ink jet method, or a printing method is particularly preferable. Further, different film forming methods may be applied for each layer.

When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C., a vacuum degree of 10 ⁻⁶ Pa to 10 ⁻² Pa, and a vapor deposition rate of 0 It is desirable to select appropriately within a range of 0.01 nm to 50 nm / second, a substrate temperature of −50 ° C. to 300 ° C., and a film thickness of 0.1 nm to 5 μm.

  After forming these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order.

<Application>
The organic electroluminescence element of the present invention can be used as a display device, a display, or various light sources. Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Although it is not limited to this, it can be effectively used especially as a backlight of a liquid crystal display device combined with a color filter and a light source for illumination. In the organic electroluminescence element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

<Display device>
The display device of the present invention will be described.

  The image display apparatus using the organic EL element of the present invention may be monochromatic or multicolor. In the case of a multicolor display device, a shadow mask is provided for each color light emitting unit, and a light emitting layer is formed for each color by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  When patterning is performed on the light emitting unit, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  In the case of a single color, for example, white, a light emitting layer is formed on one surface by a vapor deposition method, a casting method, a spin coating method, an ink jet method, a printing method or the like without patterning.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order.

  When a DC voltage is applied to the image display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  In the case of a white display device, it can be used as a display device, a display, or various light sources. In display devices and displays, full-color display is possible by using a white organic EL element as a backlight.

  Examples of the display device and display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in an automobile. In particular, it may be used as a display device for reproducing still images and moving images.

  Light emitting sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, optical storage media light sources, electrophotographic copying machine light sources, optical communication processing light sources, optical sensor light sources, etc. For example, but not limited to.

《Lighting device》
The lighting device of the present invention will be described.

  The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The use of the organic EL element having such a resonator structure is as a light source for an optical storage medium, an electrophotographic copying machine, and the like. Light sources, optical communication processor light sources, optical sensor light sources, and the like.

  Further, the organic EL element of the present invention may be used as a kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a type for directly viewing a still image or a moving image. It may be used as a display device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full color display device can be produced by using two or more organic EL elements of the present invention having different emission colors.

  When the organic EL device of the present invention is used as a white light emitting device, full color display can be performed by combination with a BGR color filter.

  The organic EL element according to the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device.

  Hereinafter, an example of a display device having the organic EL element of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below.

  In the figure, the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions (details are shown in FIG. Not shown).

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region that emit light on the same substrate.

  When the organic EL device of the present invention is used as a white light emitting device, full color display can be performed by combination with a BGR color filter.

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full-color display can be performed by using a white light-emitting organic EL element as the organic EL element 10 divided into a plurality of pixels and combining it with a BGR color filter.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the organic EL element 10 emits light by the switching transistor 11 and the driving transistor 12 that are active elements for the organic EL elements 10 of the plurality of pixels, and the organic EL elements 10 of the plurality of pixels 3 emit light. It is carried out. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.

  The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic view of a passive matrix display device. A plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a grid pattern so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

  In the white organic EL element concerning this invention, you may pattern by a metal mask, an inkjet printing method, etc. at the time of film forming as needed. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  Thus, in addition to the display device and display, the white light-emitting organic EL element of the present invention can be used as various light sources, lighting devices, household lighting, interior lighting, and a kind of lamp such as an exposure light source. It is also useful for display devices such as backlights for liquid crystal display devices.

  Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

Example 1
<Preparation of organic EL elements 1-1 to 1-24>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of copper phthalocyanine (CuPc) is put into a molybdenum resistance heating boat, and 200 mg of α-NPD is put into another molybdenum resistance heating boat. 200 mg of Exemplified Compound H-1 is put in a resistance heating boat made of 200, 200 mg of Exemplified Compound H-44 is put in another resistance heating boat made of Molybdenum, and 100 mg of Illustrative phosphorescent compound 1-99 is put in another resistance heating boat made of Molybdenum. Further, 200 mg of BAlq was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Then, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc is energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. To form a 20 nm hole injection layer. Provided.

  Further, the heating boat containing α-NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec to provide a 20 nm hole transport layer.

  Further, the heating boat containing Exemplified Compound H-1 and Exemplified Phosphorescent Compound 1-99 was energized and heated, and deposited on the hole transport layer at vapor deposition rates of 0.1 nm / sec and 0.006 nm / sec, respectively. Co-evaporated to provide a 20 nm light emitting layer A.

  Further, the heating boat containing Exemplified Compound H-44 and Exemplified Phosphorescent Compound 1-99 was energized and heated. A 20 nm light-emitting layer B was provided by vapor deposition.

  Furthermore, it supplied with electricity to the said heating boat containing BAlq, it heated, and it vapor-deposited on the said light emitting layer B with a vapor deposition rate of 0.1 nm / sec, and provided the electron carrying layer with a film thickness of 30 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 1-1 was produced.

  In the organic EL element 1-1, the organic EL element is the same as the organic EL element 1-1 except that the host compound, the doping concentration, and the film thickness of the light emitting layer A and the light emitting layer B are changed as shown in Table 1. 1-2 to 1-24 were produced.

<Evaluation>
The external extraction quantum efficiency (%) was measured by applying a constant current of ^2.5 mA / cm ² at 23 ° C. in a dry nitrogen gas atmosphere for the produced organic EL device. The lifetime (time) was measured as the time required for the luminance to drop to half of the luminance immediately after the start of light emission when driven at an initial luminance of 300 cd / m ² .

  The obtained results are shown in Table 1. Here, the measurement results of the external extraction quantum efficiency and the light emission lifetime in Table 1 are expressed as relative values when the measured value of the organic EL element 1-15 is 100.

Example 2
<Preparation of organic EL elements 2-1 to 2-9>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of copper phthalocyanine (CuPc) is put into a molybdenum resistance heating boat, and 200 mg of α-NPD is put into another molybdenum resistance heating boat. 200 mg of Exemplified Compound H-1 is put into a resistance heating boat made of 200, 200 mg of Exemplified Compound H-44 is put into another resistance heating boat made of molybdenum, and 100 mg of Illustrative Phosphorescent Compound 1-79 is put into another resistance heating boat made of molybdenum. Further, 200 mg of BAlq was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Then, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc is energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. To form a 20 nm hole injection layer. Provided.

  Further, the heating boat containing α-NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec to provide a 20 nm hole transport layer.

  Further, the heating boat containing Exemplified Compound H-1 and Exemplified Phosphorescent Compound 1-79 was energized and heated, and deposited on the hole transport layer at deposition rates of 0.1 nm / sec and 0.006 nm / sec, respectively. Co-evaporated to provide a 20 nm light emitting layer A.

  Further, the heating boat containing Exemplified Compound H-44 and Exemplified Phosphorescent Compound 1-79 was energized and heated, and both were deposited on the luminescent layer A at vapor deposition rates of 0.1 nm / sec and 0.006 nm / sec, respectively. A 20 nm light-emitting layer B was provided by vapor deposition.

  Furthermore, it supplied with electricity to the said heating boat containing BAlq, it heated, and it vapor-deposited on the said light emitting layer B with a vapor deposition rate of 0.1 nm / sec, and provided the electron carrying layer with a film thickness of 30 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 2-1 was produced.

  In the organic EL element 2-1, the organic compound is the same as the organic EL element 2-1, except that the light emitting layer A and the host compound, dopant, doping concentration and film thickness of the light emitting layer B are changed as shown in Table 2. EL elements 2-2 to 2-9 were produced.

<Evaluation>
The external extraction quantum efficiency (%) was measured by applying a constant current of ^2.5 mA / cm ² at 23 ° C. in a dry nitrogen gas atmosphere for the produced organic EL device. The lifetime (time) was measured as the time required for the luminance to drop to half of the luminance immediately after the start of light emission when driven at an initial luminance of 300 cd / m ² .

  The obtained results are shown in Table 2. Here, among the measurement results of the external extraction quantum efficiency and the light emission lifetime in Table 2, the organic EL elements 2-1 to 2-3 are expressed as relative values when the measured value of the organic EL element 2-2 is 100, The organic EL elements 2-4 to 2-6 are expressed as relative values when the measured value of the organic EL element 2-5 is 100, and the organic EL elements 2-7 to 2-9 are measured by the organic EL element 2-8. Expressed as a relative value when the value is 100.

Example 3
<Preparation of organic EL elements 3-1 to 3-6>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of copper phthalocyanine (CuPc) is put into a molybdenum resistance heating boat, and 200 mg of α-NPD is put into another molybdenum resistance heating boat. 200 mg of TCTA is put into a resistance heating boat, 200 mg of BPhen is put into another resistance heating boat made of molybdenum, 100 mg of the phosphorescent compound 1-9 is put into another resistance heating boat made of molybdenum, and another resistance heating made of molybdenum 200 mg of BAlq was put into a boat and attached to a vacuum deposition apparatus.

Then, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing CuPc is energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. To form a 20 nm hole injection layer. Provided.

  Further, the heating boat containing α-NPD was energized and heated, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec to provide a 20 nm hole transport layer.

  Further, the heating boat containing TCTA and exemplified phosphorescent compound 1-9 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.1 nm / sec and 0.006 nm / sec, respectively. A 20 nm light-emitting layer A was provided.

  Further, the heating boat containing BPhen and the exemplified phosphorescent compound 1-9 was energized and heated, and co-deposited on the light emitting layer A at a deposition rate of 0.1 nm / sec and 0.006 nm / sec, respectively, to 20 nm. The light emitting layer B was provided.

  Further, the heating boat containing BPhen was energized and heated, and deposited on the light emitting layer B at a deposition rate of 0.1 nm / sec to provide an electron transport layer having a thickness of 30 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride was vapor-deposited as a cathode buffer layer, and also aluminum 110nm was vapor-deposited, the cathode was formed, and the organic EL element 3-1 was produced.

  In the organic EL element 3-1, the organic compound is the same as the organic EL element 3-1, except that the host compound, the dopant, the doping concentration and the film thickness of the light emitting layer A and the light emitting layer B are changed as shown in Table 3. EL elements 3-2 to 3-6 were produced.

<Evaluation>
The external extraction quantum efficiency (%) was measured by applying a constant current of ^2.5 mA / cm ² at 23 ° C. in a dry nitrogen gas atmosphere for the produced organic EL device. The lifetime (time) was measured as the time required for the luminance to drop to half of the luminance immediately after the start of light emission when driven at an initial luminance of 300 cd / m ² .

  The obtained results are shown in Table 3. Here, the measurement results of the external extraction quantum efficiency and the light emission lifetime in Table 3 are expressed as relative values when the measured value of the organic EL element 3-2 is 100.

  As can be seen from a comparison between the organic EL element 1-1 and 1-15 and 1-17, it can be seen that the quantum efficiency and lifetime of external extraction are greatly improved by using two light emitting layers. This is thought to be because the recombination region can be moved away from the light emitting layer interface, and the deterioration at the light emitting layer interface that causes the luminance deterioration of the organic EL element can be suppressed. Further, as can be seen by comparing the organic EL elements 1-1 and 1-2, both the external extraction quantum efficiency and the lifetime were further improved by making the doping concentration of the light emitting layer A higher than the doping concentration of the light emitting layer B. As can be seen from the results of 1-5 to 1-14 and 1-18 to 1-24, the light-emitting host was not limited to H-1 and H-44, and similar effects were obtained.

  Further, as can be seen from the results of the organic EL element 1-4, when a mixed layer of two types of host and dopant is provided between the light emitting layer A and the light emitting layer B, the barrier at the interface between the two layers is relaxed, Lifetime improved.

  As can be seen from the results of the organic EL elements 2-1 to 2-9, the dopant used in the present invention is not limited to 1-99, and the effect can be obtained if the compound is represented by the general formula (1) of the present invention. I understand that there is.

  Further, as can be seen from the results of the organic EL elements 3-1 to 3-6, the dopant used in the present invention is not limited to any compound, and the effect may not be exhibited unless it has the structure of the present invention. I understand.

  In addition, the results of Examples 1, 2, and 3 show that the effect is further enhanced when the phosphorescence emission wavelength is 480 nm or less.

Example 4
<< Production of Organic EL Elements 4-1 to 4-14 >>
In the organic EL devices 1-1 to 1-14, α-NPD was changed to a laminate of m-MTDATA: F4-TCNQ (99: 1 (mass ratio)) co-deposited film 10 nm and α-NPD film 10 nm, and BAlq was changed to Organic EL elements 4-1 to 4-14 were produced in the same manner except that the HBL1 film was 10 nm and the BPhen: Cs (mass ratio 75:25) co-deposited film was 20 nm, and lithium fluoride was not deposited. .

  It was confirmed that each of the obtained organic EL elements 4-1 to 4-14 was reduced in driving voltage by 3V to 6V as compared with the organic EL elements 1-1 to 1-14.

  Similarly, when the elements of the present invention of Example 2 and Example 3 were modified in the same manner, the same effect was obtained.

Example 5
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water at 3000 rpm for 30 seconds. After forming the film by spin coating, the film was dried at 200 ° C. for 1 hour to provide a 30 nm-thick hole transport layer.

  The substrate was transferred to a nitrogen atmosphere, and a solution obtained by dissolving 100 mg of H-44 and 10 mg of 1-99 in 10 ml of toluene was formed into a light emitting layer A by spin coating at 3000 rpm for 30 seconds. Furthermore, a solution obtained by dissolving 100 mg of H-64 and 10 mg of 1-99 in a mixed solvent of 10 ml of methylene chloride-methanol (1: 9) was formed into a film by a spin coating method at 3000 rpm for 30 seconds to form a light emitting layer B. It was.

  Since H-44 does not dissolve in a mixed solvent of methylene chloride-methanol (1: 9) in which H-64 is dissolved, a laminated structure can be formed. Heating was performed in vacuum at 60 ° C. for 1 hour to form two light emitting layers.

This was attached to a vacuum deposition apparatus, and then the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and BAlq was deposited at 30 nm at a deposition rate of 0.1 nm / s to form an electron transport layer.

  A cathode was formed by vapor-depositing 0.5 nm of lithium fluoride as a cathode buffer layer and 110 nm of aluminum as a cathode, to fabricate an organic EL element 4-1.

  Thus, the organic EL element of the present invention can be produced by coating.

  Moreover, the same effect as Example 1 was able to be acquired also in the organic EL element 4-1 obtained by application | coating.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10, 101 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part

Claims (12)

In the organic electroluminescence device having at least two light-emitting layers containing a phosphorescent compound represented by the following general formula (1), the host and the second light emission constituting the light-emitting layer A which is the first light-emitting layer An organic electroluminescence device characterized in that a host constituting the light emitting layer B which is a layer is different.

[Wherein, R ₁ represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. n1 represents the integer of 0-5. B _{1 to} B ₅ represent a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom, and at least one of B _{1 to} B ₅ represents a nitrogen atom. M ₁ represents a group 8 to group 10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents an atomic group which forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. ] In Formula (1), electroluminescent device according to claim 1, nitrogen-containing heterocyclic ring formed by B ₁ .about.B ₅ is characterized in that an imidazole ring. 3. The organic electroluminescence element according to claim 1, wherein the general formula (1) is represented by the following general formula (2).

[In formula, R < ₁ >, R < ₂ >, R < ₃ > represents a substituent. Z represents a nonmetallic atom group necessary for forming a 5- to 7-membered ring. n1 represents the integer of 0-5. M ₁ represents a group 8 to group 10 metal in the periodic table. X ₁ and X ₂ represent a carbon atom, a nitrogen atom or an oxygen atom, and L ₁ represents an atomic group which forms a bidentate ligand together with X ₁ and X ₂ . m1 represents an integer of 1, 2 or 3, m2 represents an integer of 0, 1 or 2, and m1 + m2 is 2 or 3. ] In the said General formula (2), the substituent represented by R < ₂ > is represented by following General formula (3), The organic electroluminescent element of Claim 3 characterized by the above-mentioned.

[Wherein R ₄ represents a substituent having a steric parameter value (Es value) of −0.5 or less. R ₅ represents a substituent, and n5 represents an integer of 0 to 4. In the formula, * indicates a bonding position. ] The phosphorescence wavelength of the phosphorescence-emitting compound represented by the said General formula (1) is less than 480 nm, The organic electroluminescent element of any one of Claims 1-4 characterized by the above-mentioned. The phosphorescent compound represented by the general formula (1) contained in the light emitting layer A and the phosphorescent compound represented by the general formula (1) contained in the light emitting layer B are the same compound. The organic electroluminescent element according to any one of claims 1 to 5. The organic light-emitting device according to claim 1, wherein the light-emitting layer A and the light-emitting layer B are adjacent to each other. 8. The organic electroluminescence device according to claim 1, wherein at least one light emitting layer contains a carbazole derivative. At least 1 light emitting layer contains a furan derivative, The organic electroluminescent element of any one of Claims 1-7 characterized by the above-mentioned. The organic electroluminescence device according to claim 1, wherein at least one light emitting layer contains an azacarbazole derivative. The illuminating device provided with the organic electroluminescent element of any one of Claims 1-10. A display device comprising the organic electroluminescence element according to claim 1.

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