JP5747555B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

  The present invention relates to an organic electroluminescence element, a display device including the organic electroluminescence element, and a lighting device.

  An organic electroluminescence element (hereinafter also referred to as an organic EL element) has a structure in which a light emitting layer containing a light emitting compound is sandwiched between a cathode and an anode, and recombines by injecting electrons and holes into the light emitting layer. Is an element that emits light by using the emission of light (fluorescence / phosphorescence) when excitons are generated by excitons, and can emit light at a voltage of several volts to several tens of volts. Therefore, it is attracting attention as a next-generation flat display and illumination.

  For organic EL elements for practical use in the future, development of organic EL elements that emit light efficiently and with high brightness with lower power consumption is desired, and research and development on materials and layer structures are being carried out all over the world. Yes.

  As the development of organic EL elements for practical use, since organic EL elements using phosphorescence emission from an excited triplet in which the upper limit of internal quantum efficiency is 100% have been reported (for example, see Non-Patent Document 1). ), Studies of materials that exhibit phosphorescence at room temperature have been actively conducted (for example, see Non-Patent Document 2 and Patent Document 1).

  As a material that exhibits phosphorescence at room temperature, heavy metal complexes such as iridium complexes have been studied, and tris (2-phenylpyridine) iridium complexes are widely known (for example, Non-Patent Document 3). In addition to tris (2-phenylpyridine) iridium complexes, iridium complexes having phenylimidazole ligands, imidazophenanthridine ligands, and carbene ligands are disclosed (see, for example, Patent Documents 2 and 3). ). As host compounds of these phosphorescent dopants, carbazole derivatives represented by CBP and m-CP and carbazole multimers having a plurality of carbazoles are well known (see, for example, Patent Documents 4, 5 and 6). ).

  However, in any organic EL element, the lifetime and luminous efficiency of the organic EL element were not satisfactory.

  Moreover, in order to use an organic EL element for a display or illumination, it is indispensable that uniform light emission is obtained over the entire light emitting surface and that the light emission stability over a long time is required. However, there are currently problems such as generation of non-light emitting points called dark spots by continuous driving, voltage increase by continuous driving, and light emission unevenness in the light emitting surface, and improvements are demanded.

US Pat. No. 6,097,147 International Publication No. 2006/046980 Pamphlet International Publication No. 2005/019373 Pamphlet Japanese Patent No. 3139321 International Publication No. 2006/061759 Pamphlet International Publication No. 2007/0777810 Pamphlet

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) C. Adachietal. , Appl. Phys. Lett. 79, 2082-2084 (2001)

  The present invention has been made in view of the above problems, and its purpose is to exhibit high luminous efficiency, a long luminous lifetime, a low driving voltage, and improved uneven light emission over time during continuous light emission. An object of the present invention is to provide an organic electroluminescence element, a display device and an illumination device including the organic electroluminescence element.

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

1. The anode and cathode have a hole transport layer and a light emitting layer, and at least one of the light emitting layers contains a compound represented by the following general formula ( 1-2 ) and a phosphorescent dopant. And the organic electroluminescent element characterized by containing the compound represented by the following general formula (3-1) in the said positive hole transport layer.

(In the formula, Ra, Rb, and R _{1 to} R ₁₄ each independently represent a hydrogen atom , a substituent that does not include a 9-carbazolyl group, or a substituent that does not include a diphenylamino group .)

_(Wherein, Z 1 to Z ₅ represents an integer of 1-5 .n1 represents a hydrogen atom or a substituent, n2, n3 represents an integer of 1 to 4, n represents an integer of 4 or more.)

2. The anode and the cathode have a hole transport layer and a light emitting layer, and at least one layer of the light emitting layer contains a compound represented by the following general formula (1-3) and a phosphorescent dopant. And the organic electroluminescent element characterized by containing the compound represented by the following general formula (3-1) in the said positive hole transport layer .

（式中、Ｚ_１〜Ｚ_５は水素原子または置換基を表す。ｎ１は１〜５の整数を表し、ｎ２、ｎ３は１〜４の整数を表し、ｎは４以上の整数を表す。）
３．前記リン光発光性ドーパントが下記一般式（２−２）で表されることを特徴とする前記１または２に記載の有機エレクトロルミネッセンス素子。 (In the formula, Rc, Rd, Re and R _{1 to} R ₁₄ each independently represent a hydrogen atom or a substituent. )

_(Wherein, Z 1 to Z ₅ represents an integer of 1-5 .n1 represents a hydrogen atom or a substituent, n2, n3 represents an integer of 1 to 4, n represents an integer of 4 or more.)
3 . 3. The organic electroluminescence device according to 1 or 2 , wherein the phosphorescent dopant is represented by the following general formula (2-2).

(In the formula, R ′ _{1 to} R ′ ₄ and R′a to R′c each independently represent a hydrogen atom or a substituent. M1 represents an integer of 1 to 3, and m2 represents an integer of 0 to 2. M1 + m2 is 3. Ya-L ₁ -Yb represents a bidentate ligand, Ya and Yb each independently represent a carbon atom, a nitrogen atom, or an oxygen atom, and L ₁ together with Ya and Yb Represents an atomic group forming a bidentate ligand, and M represents a group 8-10 transition metal in the periodic table.
4 . 3. The organic electroluminescence device as described in 1 or 2 above, wherein the phosphorescent dopant is represented by the following general formula (2-3).

(In the formula, R ′ _{1 to} R ′ ₄ and R′a to R′c each independently represent a hydrogen atom or a substituent. M1 represents an integer of 1 to 3, and m2 represents an integer of 0 to 2. M1 + m2 is 3. Ya-L ₁ -Yb represents a bidentate ligand, Ya and Yb each independently represent a carbon atom, a nitrogen atom, or an oxygen atom, and L ₁ together with Ya and Yb Represents an atomic group forming a bidentate ligand, and M represents a group 8-10 transition metal in the periodic table.
5 . At least one of Ra, Rb or R _{1 to} R _{14 in} the general formula (1-2), or Rc, Rd, Re, or R _{1 to} R _{14 in} the general formula (1-3) is substituted or unsubstituted. The organic electroluminescence device according to any one of 1 to 4 , which is a dibenzofuryl group or a dibenzothienyl group.

6 . Wherein Ra or Rb of general formula (1-2), or, wherein Rc of the general formula (1-3), at least one of Rd or Re is, that it is a substituted or unsubstituted dibenzo furyl group or a dibenzothienyl group 6. The organic electroluminescence device according to any one of 1 to 5 , which is characterized by the above.

7 . Difference HOMO level of the general formula (1 2) or the compound represented by Formula HOMO level and the formula of the compound represented by (1-3) (3-1) 0.5 7. The organic electroluminescence device according to any one of 1 to 6 , wherein the organic electroluminescence device is smaller than eV .

8 . A display device comprising the organic electroluminescence element according to any one of 1 to 7 above.

9 . 8. An illuminating device comprising the organic electroluminescent element according to any one of 1 to 7 above.

  According to the present invention, an organic electroluminescence device that exhibits high luminous efficiency, has a long light emission lifetime, has a low driving voltage, and has improved uneven light emission over time during continuous light emission, and a display including the organic electroluminescence device Device and lighting device could be provided.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. FIG. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full color display device. It is the schematic of an illuminating device. It is a schematic diagram of an illuminating device.

As described in the patent document 4, 5 and 6, which is already known that compounds represented by the following following general formula (1-1) are useful as a host compound. However, the present inventors have studied in detail, in the organic EL device using a combination of phosphorescent dopant in a host compound and a blue light emitting represented by the following general formula (1-1), the uneven light emission during continuous light emission The problem of occurring was found and further improvement was needed.

  The present inventors presume that the cause of unevenness in light emission is due to a change in the properties of the film caused by heat generated during continuous light emission, and further studies have been conducted. It is known that heat is generated in the organic EL element during light emission. However, when a material having a low Tg (glass transition temperature) or a melting point is used, the property of the film is changed by the generated heat, which is a cause of uneven light emission. This is thought to be the cause. Another possible cause is charge accumulation due to the hole injection property at the interface between the hole transport layer adjacent to the light emitting layer and the light emitting layer. In particular, the properties of the hole transport layer and the light emitting layer change due to the heat during continuous light emission, and the state of the interface changes. Estimated.

  As a result of the study, it has been found that by using the compound represented by the general formula (3-1) as the hole transport material, the light emission unevenness at the time of continuous light emission is improved. This is presumably because the compound represented by the general formula (3-1) has a high Tg (glass transition temperature) and can form a film having excellent heat resistance. For this reason, it is stable against heat generated by continuous light emission, and it is considered that uneven light emission due to continuous light emission can be reduced.

一般式（１−１）において、Ｘ _１ 〜Ｘ _４ はそれぞれ独立して単結合またはＮＲを表し、Ｒは水素原子または置換基を表す。Ｘ _１ またはＸ _２ の少なくとも１つはＮＲであり、かつ、Ｘ _３ またはＸ _４ の少なくとも１つはＮＲである。Ｒ _１ 〜Ｒ _１４ はそれぞれ独立して水素原子または置換基を表す。 << Compound Represented by Formula (1-1) >>
The present invention is characterized by containing a compound and phosphorescent dopant represented by the following following general formula (1-1) in at least one layer of the light-emitting layer.

In General Formula (1-1), X _{1 to} X ₄ each independently represent a single bond or NR, and R represents a hydrogen atom or a substituent. At least one of X ₁ or X ₂ is NR, and at least one of X ₃ or X ₄ is NR. R _{1 to} R ₁₄ each independently represents a hydrogen atom or a substituent.

In the general formula (1-1), examples of the substituent represented by R _{1 to} R ₁₄ include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, Hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl group, allyl group, etc.), alkynyl group ( For example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (aromatic hydrocarbon group, aromatic carbocyclic group, aryl group, etc.), for example, phenyl group, chlorophenyl group, mesityl group, tolyl group, xylyl Group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indium Nyl group, pyrenyl group, triphenylenyl group, biphenylyl group), aromatic heterocyclic group (for example, furyl group, thienyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazinyl group, imidazolyl group, pyrazolyl group, thiazolyl group) Quinazolinyl group, phthalazinyl group, carbazolyl group, azacarbazolyl group (in which any one or more of the carbon atoms constituting the carbazole ring of the carbazolyl group are replaced by a nitrogen atom), benzofuryl group, dibenzofuryl group, azadibenzo group A furyl group (in which one or more carbon atoms constituting the dibenzofuran ring of the dibenzofuryl group are replaced by a nitrogen atom), a benzothienyl group, an indolyl group, a dibenzothienyl group, a benzoimidazolyl group, an oxazolyl group, a benzooxa group Ryl group, quinoxalinyl group, isoxazolyl group, isothiazonyl group, indolocarbazolyl group, hexaazatriphenylenyl group, benzodifuranyl group, benzodithienyl group, phosphor group, silolyl group, borol group, bipyridyl group, etc.), heterocyclic ring Group (for example, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.) , Cycloalkoxy groups (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy groups (eg, phenoxy group, naphthyloxy group, etc.), alkylthio groups (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, Hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, etc.) , 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, octylaminosulfonyl group 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, octyl) Carbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group (for example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group) , Dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonyl group) 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, phenylamino Carbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethyl) Ruureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 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 (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexyl) Sulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (phenylsulfonyl group, naphthylsulfonyl) Group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, phenylamino group) , Diphenylamino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg fluoromethyl group, trifluoromethyl group, pentane) Fluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group, etc.), phosphono group And a hydroxy group.

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

In General Formula (1-1), X _{1 to} X ₄ each independently represent a single bond or NR. However, either _one of X ₁ or X ₂ is NR and either one of X ₃ or X ₄ is NR. Here, R represents a hydrogen atom or a substituent, and the substituent is synonymous with the substituent represented by R _{1 to} R ₁₄ in the general formula (1-1).

  Moreover, it is preferable that HOMO of the compound represented by General formula (1-1) is -5.1 eV--4.3 eV.

<< Compound Represented by Formula (1-2) >>
The compound represented by the general formula (1-1) is more preferably a compound represented by the general formula (1-2) because the HOMO of the compound becomes shallow.

In General Formula (1-2), Ra, Rb, and R _{1 to} R ₁₄ each independently represent a hydrogen atom or a substituent. The substituent is synonymous with the substituent represented by _R 1 _{to R 14} in the general formula (1-1).

<< Compound Represented by Formula (1-3) >>
The compound represented by the general formula (1-1) is preferably a compound represented by the general formula (1-3).

In the general formula (1-3) represents Rc, Rd and _Re, the R 1 _{to R 14} each independently represent a hydrogen atom or a substituent. The substituent is synonymous with the substituent represented by _R 1 _{to R 14} in the general formula (1-1).

  The compounds represented by the general formulas (1-1) to (1-3) have an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, an alkoxy group, and an amino group. Among them, it is preferable to have an aryl group. Furthermore, it is preferable that the compound represented by the general formula (1-1) to the general formula (1-3) has a dibenzofuranyl group or a dibenzosulfonyl group.

  Moreover, it is preferable that HOMO of the compound represented by the general formula (1-2) is −5.1 eV to −4.3 eV.

  Hereinafter, although the specific example of a compound represented by general formula (1-1)-general formula (1-3) is shown, this invention is not limited to these.

<< HOMO (highest occupied orbit), LUMO (lowest orbit) >>
Here, the values of HOMO and LUMO according to the present invention are Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al., Gaussian, Inc., Pittsburgh, software for molecular orbital calculation manufactured by Gaussian, USA. PA, 2002), and is defined as a value (eV unit converted value) calculated by performing structure optimization using B3LYP / 6-31G * as a keyword. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.

<< Compound Represented by Formula (2-1) >>
The present invention is characterized in that a phosphorescent dopant is contained in at least one of the light emitting layers.

In the organic EL device of the invention, the phosphorescent dopant, a compound represented by the following following general formula (2-1) is preferred. The following describes the compound represented by the following general formula (2-1). Note that the organic phosphorescent dopant represented by the following general formula (2-1) is contained as a light emitting dopant in the light emitting layer of the organic EL device of the present invention, component layers other than the light-emitting layer (the present invention The constituent layers of the EL element may be described later in detail.)

In the general formula (2-1), Y _{1 to} Y ₅ and Y ′ _{1 to} Y ′ ₄ represent CR or NR, and Y ′ ₅ represents CR, NR or RC═CR ′. R and R ′ represent a hydrogen atom or a substituent. R, examples of substituents R ', in general formula _(1-1), is synonymous with the substituents represented by R 1 _{to R 14.}

  In General Formula (2-1), m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 represents 2 or 3. m2 is preferably 0.

In the general formula (2-1), examples of the bidentate ligand represented by Ya-L ₁ -Yb include phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol, acetylacetone, picolinic acid, and the like. Is mentioned. These ligands may further have the above substituent.

  In the general formula (2-1), M represents a group 8-10 transition metal in the periodic table of elements, and examples thereof include Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, and Pt. Ir and Pt are preferable, and among them, Ir is preferably used.

<< Compound Represented by Formula (2-2) >>
In the organic EL device of the present invention, the phosphorescent dopant is preferably a compound represented by the general formula (2-2).

In General Formula (2-2), R ′ _{1 to} R ′ ₄ and R′a to R′c each independently represent a hydrogen atom or a substituent. Examples of the substituent in the general formula _(1-1), is synonymous with the substituents represented by R 1 _{to R 14.}

  In General Formula (2-2), m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 represents 2 or 3. m2 is preferably 0.

In the general formula (2-2), bidentate ligand represented by _Ya-L 1 -Yb are the compounds of formula (2-1), coordination of bidentate represented by _Ya-L 1 -Yb Synonymous with rank.

  In general formula (2-2), M is synonymous with general formula (2-1).

<< Compound Represented by Formula (2-2a) >>
Among the compounds represented by the general formula (2-2), a compound represented by the following general formula (2-2a) is particularly preferable.

In the formula, R ′ _{1 to} R ′ ₄ and R′b to R′c each independently represent a hydrogen atom or a substituent. Z _B represents an atomic group necessary for forming a hydrocarbon ring group or a heterocyclic group. m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 is 3. Ya-L ₁ -Yb represents a bidentate ligand, and Ya and Yb each independently represent a carbon atom, a nitrogen atom, or an oxygen atom. L ₁ represents an atomic group that forms a bidentate ligand together with Ya and Yb. M represents a transition metal of group 8 to 10 in the periodic table.

In the general formula (2-2a), the substituents represented by R ′ _{1 to} R ′ ₄ and R′b to R′c are represented by R _{1 to} R ₁₄ in the general formula (1-1). It is synonymous with the substituent.

In the general formula (2-2a), hydrocarbon ring group represented by Z _B, a non-aromatic hydrocarbon ring group include an aromatic hydrocarbon ring group, a non-aromatic hydrocarbon ring group, A cyclopropyl group, a cyclopentyl group, a cyclohexyl group, etc. are mentioned. These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

In the general formula (2-2a), R′d has a steric parameter value (Es value) located at the ortho position from the position where the hydrocarbon ring group or heterocyclic group composed of Z _B is bonded to the imidazole ring. Although it represents a substituent of −0.5 or less, it is preferably −7.0 to −0.6, and most preferably −7.0 to −1.0.

(Stereoscopic parameter (Es value))
The three-dimensional parameter (Es value) according to the present invention will be described.

  The steric parameter (Es value) according to the present invention is a steric parameter derived from chemical reactivity. The smaller this value, the more sterically bulky substituent. In general, in ester hydrolysis under acidic conditions, it is known that the influence of a substituent on the progress of the reaction may be considered only as a steric hindrance. The Es value is obtained by quantifying the steric hindrance.

The Es value of the substituent X is represented by the following chemical reaction formula: X—CH ₂ COORX + H ₂ O → X—CH ₂ COOH + RXOH
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 COORY + H ₂ O → CH ₃ COOH + RYOH
(RX is the same as RY) represented by the following formula from the reaction rate constant kH when the acetate corresponding to the above α-monosubstituted acetate is hydrolyzed under acidic conditions.

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). In addition, the specific numerical values are also described in “Structure-activity relationship of drugs” (Area No. 122 in Chemistry, 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, when substituents having a steric parameter value (Es value) of −0.5 or less, for example, keto-enol tautomers can exist in R and R ′, the keto moiety is regarded as an enol isomer. Es value is converted. Even when other tautomerism exists, the Es value is converted by the same conversion method. Furthermore, the substituent having an Es value of −0.5 or less is preferably an electron-donating group (also referred to as an electron-donating substituent) in terms of electronic effects.

(Electron donating group)
In the present invention, the electron-donating substituent is a substituent having a negative Hammett σp value as described below, and such a substituent has an electron on the bonding atom side compared to a hydrogen atom. Easy to give.

  Specific examples of the substituent exhibiting electron donating properties include a hydroxyl group, an alkoxy group (for example, methoxy group), an acetyloxy group, an amino group, a dimethylamino group, an acetylamino group, and an alkyl group (for example, a methyl group, an ethyl group). , A propyl group, a t-butyl group, etc.) and an aryl group (for example, a phenyl group, a mesityl group, etc.). For the Hammett σp value, for example, the following documents can be referred to.

  The Hammett σp value according to the present invention refers to Hammett's substituent constant σp. Hammett's σp value is a substituent constant determined by Hammett et al. From the electronic effect of the substituent on the hydrolysis of ethyl benzoate. “Structure-activity relationship of drugs” (Nanedo: 1979), “Substituent” Reference can be made to the groups described in “Constants for Correlation Analysis in Chemistry and Biology” (C. Hanshand A. Leo, John Wiley & Sons, New York, 1979).

  In the present invention, the electron-donating substituent is a substituent having a negative Hammett σp value as described below, and such a substituent has an electron on the bonding atom side compared to a hydrogen atom. Easy to give.

  Specific examples of the substituent exhibiting electron donating properties include a hydroxyl group, an alkoxy group (for example, methoxy group), an acetyloxy group, an amino group, a dimethylamino group, an acetylamino group, and an alkyl group (for example, a methyl group, an ethyl group). , A propyl group, a t-butyl group, etc.) and an aryl group (for example, a phenyl group, a mesityl group, etc.). For the Hammett σp value, for example, the following documents can be referred to.

  In General Formula (2-2a), m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 represents 2 or 3. m2 is preferably 0.

In the general formula (2-2a), bidentate ligand represented by _Ya-L 1 -Yb are the compounds of formula (2-1), coordination of bidentate represented by _Ya-L 1 -Yb Synonymous with rank.

  In General Formula (2-2a), M represents a transition metal of Group 8 to 10 in the periodic table.

<< Compound Represented by Formula (2-3) >>
In the organic EL device of the present invention , the phosphorescent dopant is particularly preferably a compound represented by the general formula (2-3).

  Hereinafter, although the specific example of a compound represented by general formula (2-1)-(2-3) which concerns on this invention is shown, this invention is not limited to this.

<< Compound Represented by Formula (3-1) >>
The present invention is characterized in that the compound represented by the general formula (3-1) is contained in at least one light emitting layer.

In General Formula (3-1), Z _{1 to} Z ₅ each represents a hydrogen atom or a substituent. Examples of the substituent in the general formula _(1-1), is synonymous with the substituents represented by R 1 _{to R 14.}

  Hereinafter, although the specific example of a compound represented by general formula (3-1) of this invention is shown, this invention is not limited to this.

  Moreover, when manufacturing an organic EL element using a wet process, it is preferable that the compound represented by the said General formula (3-1) is a high molecular compound whose weight average molecular weight is 50000-500000 in polystyrene conversion. Makromol Chem. , 193, 909 pages (1992) and the like.

  Moreover, from the viewpoint of luminous efficiency and organic EL element lifetime, it is preferable that the low molecular weight component, heavy metal, and the like are not mixed and the molecular weight distribution is small.

  Specifically, the content of the organic component having a weight average molecular weight of 1000 or less is preferably 1% by mass or less, and further, the content of the organic component having a weight average molecular weight of 1000 or less is preferably 1% by mass or less. .

  Furthermore, the molecular weight distribution (MW / Mn) is preferably 3 or less, more preferably 2.5 or less.

  The content of heavy metals (Pd, Cu, Pt, etc.) is preferably 500 ppm or less, more preferably 50 ppm or less.

Synthesis Example Here, as a synthesis example of HT-15, synthesis of compounds HT-15a to HT-15d having different weight average molecular weights and molecular weight distributions is shown below.

  << Synthesis of HT-15a >>

15-1 (15.0 g) and 15-2 (18.0 g) were dissolved in 200 ml of toluene, and Aliquat 336 (1.0 g) and 30 ml of 2 mol / l sodium bicarbonate solution were added under nitrogen. The mixture was vigorously stirred and heated to reflux for 2 hours, after which 1 g of bromobenzene was added and ripened for 5 hours. The reaction solution was cooled to 60 ° C., and slowly added to a mixed solution of 3 L of methanol and 300 ml of pure water with stirring. The precipitate is collected and repeatedly washed with methanol and pure water, and then dried in a vacuum oven at 60 ° C. for 10 hours to obtain HT-15a (19.0 g, weight average molecular weight 5000, molecular weight distribution 2.2). It was. The structure of HT-15a was confirmed using ¹ H-NMR, ¹³ C-NMR and the like.

<< Synthesis of HT-15b, HT-15c, HT-15d >>
In the synthesis of HT-15a, HT-15b (weight average molecular weight 55000, molecular weight distribution 2.0) was changed in the same manner except that the reaction time was changed from 2 hours to 10 hours, and the reaction time was changed from 2 hours to 20 hours. HT-15c (weight average molecular weight 150,000, molecular weight distribution) except that the reaction time was changed from 2 hours to 50 hours in the same manner. 1.9) was obtained.

The structures of HT-15b, HT-15c, and HT-15d were confirmed using ¹ H-NMR, ¹³ C-NMR, and the like.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described. 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 unit / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer unit / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer unit / hole blocking Layer / electron transport layer / cathode (iv) anode / hole transport layer / light emitting layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) anode / anode buffer layer / hole transport layer / light emission Layer unit / hole blocking layer / electron transport layer / cathode buffer layer / cathode Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The intermediate layer may be a charge generation layer or a multi-photon unit configuration. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

  Each layer which comprises the organic EL element of this invention is demonstrated.

<Light emitting layer>
The light emitting layer according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. May be the interface between the light emitting layer and the adjacent layer.

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 5 nm to 100 nm.

  For the production of the light emitting layer, a light emitting dopant or host compound described later is used, for example, a vacuum deposition method, a wet method (also referred to as a wet process, for example, a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, Examples thereof include an inkjet method, a printing method, a spray coating method, a curtain coating method, and an LB method (Langmuir-Blodgett method). (When the compound of the present invention is used for a light emitting layer, it is preferably produced by a wet process).

  The light emitting layer of the organic EL device of the present invention contains a light emitting dopant (phosphorescent dopant (also referred to as phosphorescent dopant, phosphorescent dopant group) or fluorescent dopant) compound and a light emitting host compound. Is preferred.

(Luminescent dopant compound)
A light-emitting dopant compound (a light-emitting dopant, also simply referred to as a dopant) will be described.

  As the light-emitting dopant, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used.

(Phosphorescent dopant (also called phosphorescent dopant))
The phosphorescent dopant according to the present invention will be described.

  The phosphorescent dopant compound according to the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

  There are two types of light emission of the phosphorescent dopant in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the luminescent host compound, and this energy is used as the phosphorescent dopant. The energy transfer type in which light emission from the phosphorescent dopant is obtained by moving to the other, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant compound occurs. In any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

  In the organic EL device of the present invention, at least one of the light-emitting layers contains a phosphorescent organometallic complex (also referred to as a phosphorescent dopant or a phosphorescent dopant). Preferably contains a metal complex represented by any one of the general formulas (2-1) to (2-2).

  The phosphorescent metal complexes represented by the general formulas (2-1) to (2-2) according to the present invention are described in, for example, Inorg. Chem. 40, 1704 to 1711, etc.

  Moreover, you may use together the conventionally well-known compound etc. which are described in the following patent gazettes in the light emitting layer which concerns on this invention.

  For example, International Publication No. 00/70655 pamphlet, Japanese Patent Application Laid-Open No. 2002-280178, Japanese Patent Application Laid-Open No. 2001-181616, Japanese Patent Application Laid-Open No. 2002-280179, Japanese Patent Application Laid-Open No. 2001-181617, and Japanese Patent Application Laid-Open No. 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, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-117978, JP 2002-338588, JP 2002-170684, JP 2002-352960, WO 01/93642, JP 2002-50483, JP 2002-1000047, JP JP 2002-173684 A, JP 2002-359082 A, JP 2002-17584 A, JP 2002-363552 A, JP 2002-184582 A, JP 2003-7469 A, Special Table 2002. No. 525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-233506 Japanese Patent Laid-Open No. 2002-24175 JP, JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, 2002-343572. JP-A-2002-203678.

  Among known ones, the phosphorescent dopant is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, or a platinum compound (platinum complex). System compounds), rare earth complexes, and most preferred are iridium compounds.

(Fluorescent dopant (also called fluorescent compound))
As fluorescent dopants, coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes , Polythiophene dyes, rare earth complex phosphors, and the like, and compounds having a high fluorescence quantum yield such as laser dyes.

  In addition, the light-emitting dopant according to the present invention may be used in combination of a plurality of types of compounds, or may be a combination of phosphorescent dopants having different structures, or a combination of a phosphorescent dopant and a fluorescent dopant.

  Although the specific example of the compound used as a conventionally well-known phosphorescent dopant which may be used together below is shown, this invention is not limited to these.

(Luminescent host compound (also referred to as luminescent host))
In the present invention, the host compound has a mass ratio of 20% or more among the compounds contained in the light emitting layer, and a phosphorescence quantum yield of phosphorescence emission is 0 at room temperature (25 ° C.). Defined as less than 1 compound. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

  As the luminescent host that can be used in the present invention, the compound represented by the general formula (1-1) is used, but a known host compound may be used in combination, or a plurality of types may be used in combination. May be. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient.

  Typically, a carbazole derivative, a triarylamine derivative, an aromatic derivative, a nitrogen-containing heterocyclic compound, a thiophene derivative, a furan derivative, an oligoarylene compound or the like having a basic skeleton, or a carboline derivative or a diazacarbazole derivative (here And the diazacarbazole derivative represents one in which at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom.

  As a known light-emitting host that can be used in the present invention, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

  In the present invention, (the light emitting host of the present invention and / or a known light emitting host) may be used alone or in combination of two or more.

  By using a plurality of types of light-emitting hosts, the movement of charges can be adjusted, and the organic EL element can be made highly efficient.

  Moreover, it becomes possible to mix different light emission by using multiple types of well-known compounds used as the said phosphorescence dopant, and, thereby, arbitrary luminescent colors can be obtained.

  In addition, the light emitting host used in 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 (polymerizable light emitting host). Of course, one or more of such compounds may be used.

  Specific examples of the known light-emitting host include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Hereinafter, specific examples which may be used in combination and are used as conventionally known light-emitting hosts will be given, but the present invention is not limited thereto.

《Hole transport layer》
The hole transport layer is made of a hole transport 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 has any one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. In the present invention, the compound represented by the general formula (3-1) is used, but the following known compounds may be used in combination.

  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, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  The above-mentioned materials can be used as the hole transport material, 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, as well as two of those described in US Pat. No. 5,061,569 Having a condensed aromatic ring in the molecule, 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. Huanget. al. A so-called p-type hole transport material as 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.

  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, a printing method including an ink jet method, or an LB method. it can.

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

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 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. 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 a plurality of layers.

  The electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer. As a constituent material of the electron transport layer, any conventionally known compound may be selected and used in combination. Is possible.

  Examples of conventionally known materials used for the 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, Carbodiimide, fluorenylidenemethane derivative, anthraquinodimethane and anthrone derivative, oxadiazole derivative, carboline derivative, or at least one carbon atom of the hydrocarbon ring constituting the carboline ring of the carboline derivative is substituted with a nitrogen atom. And derivatives having a cyclic structure, hexaazatriphenylene derivatives and the like.

  Furthermore, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, or a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group can also be used as an electron transport material.

  It is also possible to use a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), 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 metals of these metal complexes are 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 the terminal substituted with an alkyl group or a sulfonic acid group can also be used as the electron transport material.

  In addition, inorganic semiconductors such as n-type-Si and n-type-SiC can also be used as the electron transport material.

  The electron transport layer is made of an electron transport material such as a vacuum deposition method, a wet method (also referred to as a wet process, such as a spin coating method, a casting method, a die coating method, a blade coating method, a roll coating method, an ink jet method, a printing method, or a spraying method. It is preferable to form the film by thinning by a coating method, a curtain coating method, an LB method (such as Langmuir-Blodgett method)).

  The method for forming the constituent layers of the organic EL element will be described in detail in the section of the method for manufacturing the organic EL element.

  Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, about 5-5000 nm, Preferably it is 5-200 nm. This electron transport layer may have a single layer structure composed of one or more of the above materials.

  Moreover, you may use by doping n type dopants, such as metal compounds, such as a metal complex and a metal halide.

  Hereinafter, although the specific example of the conventionally well-known compound (electron transport material) preferably used for formation of the electron carrying layer of the white organic EL element of this invention is given, this invention is not limited to these.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material 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, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / 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 5 μm, preferably 50 to 200 nm. In order to transmit the emitted 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.

  In addition, after the metal is formed on the cathode with a film thickness of 1 to 20 nm, a transparent or translucent cathode can be prepared by forming a conductive transparent material mentioned in the description of the anode described later on the metal. By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

<< Injection layer: electron injection layer (cathode buffer layer), hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists 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. May be.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), 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 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. Representative phthalocyanine buffer layer, hexaazatriphenylene derivative buffer layer, oxide buffer layer represented by vanadium oxide, amorphous carbon buffer layer, polymer buffer layer using conductive polymer such as polyaniline (emeraldine) or polythiophene Etc.

  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, alkali metal compound buffer layer typified by lithium fluoride and potassium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride and cesium fluoride, typified by aluminum oxide Examples thereof include an oxide buffer layer. The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

<Blocking layer: hole blocking layer, electron blocking layer>
The blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film as described above. 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.

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has 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 said electron carrying layer 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.

  The hole blocking layer includes a carbazole derivative, a carboline derivative, a diazacarbazole derivative (the diazacarbazole derivative is a nitrogen atom in which any one of carbon atoms constituting the carboline ring is cited as the host compound described above. It is preferable to contain (represented by).

  In the present invention, when a plurality of light emitting layers having different light emission colors are provided, the light emitting layer having the shortest wavelength of light emission is preferably closest to the anode among all the light emitting layers. In this case, it is preferable to additionally provide a hole blocking layer between the shortest wave layer and the light emitting layer next to the anode next to the anode. Furthermore, it is preferable that 50% by mass or more of the compound contained in the hole blocking layer provided at the position has an ionization potential of 0.3 eV or more larger than the host compound of the shortest wave emitting layer.

The ionization potential is defined by the energy required to emit electrons at the HOMO (highest occupied orbital) level of the compound to the vacuum level, and can be determined by, for example, the following method.
(1) Using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al., Gaussian, Inc., Pittsburgh PA, 2002.), a molecular orbital calculation software manufactured by Gaussian, USA, as a keyword, B3LYP / It can be determined as a value (eV unit converted value) calculated by performing structure optimization using 6-31G *. This calculation value is effective because the correlation between the calculation value obtained by this method and the experimental value is high.
(2) The ionization potential can also be obtained by a method of directly measuring by photoelectron spectroscopy. For example, a method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense, and is made of a material that has a function of transporting holes and has an extremely small ability to transport electrons, and transports electrons while transporting holes. By blocking, the recombination probability of electrons and holes can be improved.

  Moreover, the structure of the positive hole transport layer mentioned later can be used as an electron blocking layer as needed. The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) 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, these electrode materials may be formed into a thin film 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 pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material.

  Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is extracted from the anode, it is desirable that the transmittance be 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 to 1000 nm, preferably 10 to 200 nm.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate 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 polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, 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. The water vapor permeability (25 ± 0.5 ° C., relative temperature) measured by a method according to JISK7129-1992 The humidity (90 ± 2)% RH) is preferably a barrier film of 0.01 g / (m ² · 24 h) or less, and further, the oxygen permeability measured by a method in accordance with JISK 7126-1987 is It is preferable that the film has a high barrier property of 10 ⁻³ ml / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less.

  As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, 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 organic material layers. 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.

  The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight 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 substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, and ceramic substrates.

  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. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

<< Method for producing organic EL element >>
As an example of a method for producing an organic EL device, a device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer (electron injection layer) / cathode Will be described.

  First, a desired electrode material, for example, a thin film made of an anode material is formed on a suitable substrate so as to have a thickness of 1 μm or less, preferably 10 to 200 nm, and an anode is manufactured.

  Next, a thin film containing an organic compound such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, or a cathode buffer layer, which is an element material, is formed thereon.

  As a method for forming the thin film, for example, the thin film can be formed by a vacuum deposition method, a wet method (also referred to as a wet process), or the like.

  Wet methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, curtain coating, and LB, but precise thin films can be formed. In view of high productivity, a method having high suitability for a roll-to-roll method such as a die coating method, a roll coating method, an ink jet method, and a spray coating method is preferable. Different film formation methods may be applied for each layer.

  Examples of the liquid medium for dissolving or dispersing the organic EL material according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, and mesitylene. Aromatic hydrocarbons such as cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane, and organic solvents such as DMF and DMSO can be used.

  Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

  After the formation of these layers, a thin film made of a cathode material is formed thereon so as to have a thickness of 1 μm or less, preferably in the range of 50 to 200 nm, and a desired organic EL device can be obtained by providing a cathode. .

  Further, the order can be reversed, and the cathode, cathode buffer layer, electron transport layer, hole blocking layer, light emitting layer, hole transport layer, hole injection layer, and anode can be formed in this order.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 V to 40 V with the anode as + and the cathode as-. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

  The organic EL device of the present invention is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but it may be taken out halfway and subjected to different film forming methods. At that time, it is preferable to perform the work in a dry inert gas atmosphere.

<Sealing>
As a sealing means used for this invention, the method of adhere | attaching a sealing member, an electrode, and a support substrate with an adhesive agent can be mentioned, for example.

  As a sealing member, it should just be arrange | positioned so that the display area | region of an organic EL element may be covered, and concave plate shape or flat plate shape may be sufficient. Further, 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 those formed from polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, polysulfone and the like.

  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 was measured by the method according to JISK7129-1992, the oxygen permeability measured by the method according to JISK7126-1987 below 1 × 10 ⁻³ ml / (m ² · 24 h · atm). The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is preferably 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 reactive vinyl groups such as acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. be able to. Moreover, 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 like screen printing.

  In addition, it is also preferable that the electrode and the organic layer are coated on the outside of the electrode facing the support substrate with the organic layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. . 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 elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be 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 can be injected in the gas phase and liquid phase. preferable. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

  Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, 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 perchloric acid) Barium, magnesium perchlorate, and the like), and 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 on the outer side of the sealing film on the side facing the support substrate with the organic layer interposed therebetween or on the sealing film. In particular, when the 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.

《Light extraction》
The organic EL element emits light inside a layer having a refractive index higher than that of air (refractive index is about 1.7 to 2.1) and can extract only about 15% to 20% of the light generated in the light emitting layer. It is generally said. This is because light incident on the interface (interface between the transparent substrate and air) at an angle θ greater than the critical angle causes total reflection and cannot be taken out of the device, or between the transparent electrode or light emitting layer and the transparent substrate. This is because the light is totally reflected between the light and the light is guided through the transparent electrode or the light emitting layer, and as a result, the light escapes in the direction of the element side surface.

  As a method for improving the light extraction efficiency, for example, a method of forming irregularities on the surface of the transparent substrate to prevent total reflection at the interface between the transparent substrate and the air (US Pat. No. 4,774,435), A method of improving efficiency by providing a light collecting property to a substrate (Japanese Patent Laid-Open No. 63-314795), a method of forming a reflective surface on a side surface of an element (Japanese Patent Laid-Open No. 1-220394), and light emission from a substrate A method of forming an antireflection film by introducing a flat layer having an intermediate refractive index between the bodies (Japanese Patent Laid-Open No. 62-172691), a flat having a lower refractive index between the substrate and the light emitter than the substrate A method of introducing a layer (Japanese Patent Laid-Open No. 2001-202827), a method of forming a diffraction grating between any one of a substrate, a transparent electrode layer and a light emitting layer (including between the substrate and the outside) (Japanese Patent Laid-Open No. 11-283951) Gazette).

  In the present invention, these methods can be used in combination with the organic EL device of the present invention. However, a method of introducing a flat layer having a lower refractive index than the substrate between the substrate and the light emitter, or a substrate, transparent A method of forming a diffraction grating between any layers of the electrode layer and the light emitting layer (including between the substrate and the outside) can be suitably used.

  In the present invention, by combining these means, it is possible to obtain an element having higher luminance or durability.

  When a medium having a low refractive index is formed between the transparent electrode and the transparent substrate with a thickness longer than the wavelength of light, the light extracted from the transparent electrode has a higher extraction efficiency to the outside as the refractive index of the medium is lower.

  Examples of the low refractive index layer include aerogel, porous silica, magnesium fluoride, and a fluorine-based polymer. Since the refractive index of the transparent substrate is generally about 1.5 to 1.7, the low refractive index layer preferably has a refractive index of about 1.5 or less. Further, it is preferably 1.35 or less.

  The thickness of the low refractive index medium is preferably at least twice the wavelength in the medium. This is because the effect of the low refractive index layer is diminished when the thickness of the low refractive index medium is about the wavelength of light and the electromagnetic wave that has exuded by evanescent enters the substrate.

  The method of introducing a diffraction grating into an interface or any medium that causes total reflection is characterized by a high effect of improving light extraction efficiency. This method uses the property that the diffraction grating can change the direction of light to a specific direction different from refraction by so-called Bragg diffraction such as first-order diffraction and second-order diffraction. Light that cannot be emitted due to total internal reflection between layers is diffracted by introducing a diffraction grating in any layer or medium (in a transparent substrate or transparent electrode), and the light is removed. I want to take it out.

  The introduced diffraction grating desirably has a two-dimensional periodic refractive index. This is because light emitted from the light-emitting layer is randomly generated in all directions, so in a general one-dimensional diffraction grating having a periodic refractive index distribution only in a certain direction, only light traveling in a specific direction is diffracted. Therefore, the light extraction efficiency does not increase so much.

  However, by making the refractive index distribution a two-dimensional distribution, light traveling in all directions is diffracted, and light extraction efficiency is increased.

  As described above, the position where the diffraction grating is introduced may be in any of the layers or in the medium (in the transparent substrate or in the transparent electrode), but is preferably in the vicinity of the organic light emitting layer where light is generated.

  At this time, the period of the diffraction grating is preferably about 1/2 to 3 times the wavelength of light in the medium.

  The arrangement of the diffraction grating is preferably two-dimensionally repeated, such as a square lattice, a triangular lattice, or a honeycomb lattice.

<Condenser sheet>
The organic EL device of the present invention can be processed to provide, for example, a microlens array-like structure on the light extraction side of the substrate, or combined with a so-called condensing sheet, for example, in a specific direction, for example, the device light emitting surface. On the other hand, the brightness | luminance in a specific direction can be raised by condensing in a front direction.

  As an example of the microlens array, quadrangular pyramids having a side of 30 μm and an apex angle of 90 degrees are two-dimensionally arranged on the light extraction side of the substrate. One side is preferably 10 to 100 μm. If it becomes smaller than this, the effect of diffraction will generate | occur | produce and color, and if too large, thickness will become thick and is not preferable.

  As the condensing sheet, for example, a sheet that is put into practical use in an LED backlight of a liquid crystal display device can be used. As such a sheet, for example, a brightness enhancement film (BEF) manufactured by Sumitomo 3M Limited can be used.

  As the shape of the prism sheet, for example, the base material may be formed by forming a △ -shaped stripe having a vertex angle of 90 degrees and a pitch of 50 μm, or the vertex angle is rounded and the pitch is changed randomly. Other shapes may be used.

  Moreover, in order to control the light emission angle from a light emitting element, you may use together a light diffusing plate and a film with a condensing sheet. For example, a diffusion film (light-up) manufactured by Kimoto Co., Ltd. can be used.

<Application>
The organic EL element of the present invention can be used as a display device, a display, and various light emission sources. For example, lighting devices (home lighting, interior lighting), clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources of optical storage media, light sources of electrophotographic copying machines, light sources of optical communication processors, light Although the light source of a sensor etc. are mentioned, It is not limited to this, Especially, it can use effectively for the use as a backlight of a liquid crystal display device, and a light source for illumination.

In the organic EL element of the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like as needed during film formation. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the element may be patterned. In the fabrication of the element, a conventionally known method is used. Can do. The light emission color of the organic EL device of the present invention and the compound according to the present invention is shown in FIG. 4.16 on page 108 of “New Color Science Handbook” (edited by the Japan Color Society, University of Tokyo Press, 1985). It is determined by the color when the result measured with a total CS-1000 (Konica Minolta Sensing Co., Ltd.) is applied to the CIE chromaticity coordinates. Further, when the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE 1931 color system at 1000 cd / m ² is X when the 2 ° viewing angle front luminance is measured by the above method. = 0.33 ± 0.07 and Y = 0.33 ± 0.1.

<Display device>
The display device of the present invention will be described. The display device of the present invention comprises the organic EL element of the present invention.

  Although the display device of the present invention may be single color or multicolor, the multicolor display device will be described here. In the case of a multicolor display device, a shadow mask is provided only at the time of forming a light emitting layer, and a film can be formed on one surface by vapor deposition, casting, spin coating, ink jet, printing, or the like.

  In the case of patterning only the light emitting layer, the method is not limited. However, the vapor deposition method, the ink jet method, the spin coating method, and the printing method are preferable.

  The configuration of the organic EL element provided in the display device is selected from the above-described configuration examples of the organic EL element as necessary.

  Moreover, the manufacturing method of an organic EL element is as having shown to the one aspect | mode of manufacture of the organic EL element of said invention.

  In the case of applying a DC voltage to the obtained multicolor display device, light emission can be observed by applying a voltage of about 2V to 40V 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.

  The multicolor display device can be used as a display device, a display, and various light emission sources. In a display device or display, full-color display is possible by using three types of organic EL elements of blue, red, and green light emission.

  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, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  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, light sources for optical sensors, etc. The present invention is not limited to these examples.

  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 view showing an example of a display device composed of 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 a plurality of pixels based on image information from the outside. The image information is sequentially emitted to scan the image and display the 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 line 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 grid pattern and are connected to the pixels 3 at the orthogonal positions (details are illustrated). Not)

  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 on the same substrate.

  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 red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  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 light emission of the organic EL element 10 is performed by providing the switching transistor 11 and the drive transistor 12 which are active elements with respect to the organic EL element 10 of each of the plurality of pixels, and the light emission of the organic EL element 10 of each of the plurality of pixels 3. 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 by turning on / off a predetermined light emission amount by a binary image data signal. Good. 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 diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape 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.

《Lighting device》
The lighting device of the present invention will be described. The illuminating device of this invention has the said organic EL element. The organic EL element of the present invention may be used as an organic EL element having a resonator structure. The purpose of use of the organic EL element having such a resonator structure is as follows. The light source of a machine, the light source of an optical communication processing machine, the light source of a photosensor, etc. are mentioned, However, It is not limited to these. Moreover, you may use for the said use by making a laser oscillation.

  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 display for directly viewing a still image or a moving image. It may be used as a device (display).

  The driving method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

  The organic EL material of the present invention can be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of blue, green, and blue, or two using the relationship of complementary colors such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and light from the light emitting material as excitation light. Any of those combined with a dye material that emits light may be used, but in the white organic EL device according to the present invention, only a combination of a plurality of light-emitting dopants may be mixed.

  It is only necessary to provide a mask only when forming a light emitting layer, a hole transport layer, an electron transport layer, etc., and simply arrange them separately by coating with the mask. Since other layers are common, patterning of the mask or the like is not necessary. In addition, for example, an electrode film can be formed by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like, and productivity is also improved.

  According to this method, unlike a white organic EL device in which light emitting elements of a plurality of colors are arranged in parallel in an array, the elements themselves are luminescent white.

  There is no restriction | limiting in particular as a luminescent material used for a light emitting layer, For example, if it is a backlight in a liquid crystal display element, the metal complex which concerns on this invention so that it may suit the wavelength range corresponding to CF (color filter) characteristic, Any one of known luminescent materials may be selected and combined to whiten.

<< One Embodiment of Lighting Device of the Present Invention >>
One aspect of the lighting device of the present invention that includes the organic EL element of the present invention will be described.

  The non-light emitting surface of the organic EL device of the present invention is covered with a glass case, a glass substrate having a thickness of 300 μm is used as a sealing substrate, and an epoxy-based photocurable adhesive (LUX TRACK manufactured by Toagosei Co., Ltd.) is used as a sealing material. LC0629B) is applied, and this is overlaid on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and an illumination device as shown in FIGS. Can be formed.

  FIG. 5 shows a schematic diagram of a lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in addition, the sealing operation with the glass cover is to bring the organic EL element 101 into contact with the atmosphere. And a glove box under a nitrogen atmosphere (in an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more).

  FIG. 6 shows a cross-sectional view of the lighting device. In FIG. 6, 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

  The structures of the compounds used in the examples are shown below.

Example 1
<< Production of Organic EL Element 1-1 >>
Patterning was performed on a substrate (NAV-45, manufactured by AvanStrate Co., Ltd.) in which an ITO (indium tin oxide) film having a thickness of 100 nm was formed on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode 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, Baytron PAl4083, Baytron PAl4083) to 70% with pure water is formed by spin coating. Then, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  A chlorobenzene solution of the hole transport material Ha-1 was formed on the first hole transport layer by a spin coating method. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  On this 2nd hole transport layer, the host compound 22 and the butyl acetate solution of Ir-12 which is a dopant compound were formed into a film by the spin coat method, and it heat-dried at 120 degreeC for 1 hour, and formed the light emitting layer with a film thickness of 40 nm. Provided.

  On this light emitting layer, the 1-butanol solution of electron transport material ET-23 was formed into a film by the spin coat method, and the 20-nm-thick electron transport layer was provided.

This was attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa. Subsequently, lithium fluoride 1.0nm was vapor-deposited as an electron injection layer, and aluminum 110nm was vapor-deposited as a cathode, and the organic EL element 1-1 was produced.

<< Production of Organic EL Element 1-2 >>
In the production of the organic EL element 1-1, the hole transport material was replaced with Ha-2 and produced in the same manner. However, when the light emitting layer was produced, the lower layer was dissolved and an organic EL device could not be produced.

<< Production of Organic EL Element 1-3 >>
Patterning was performed on a substrate (NAV-45, manufactured by AvanStrate Co., Ltd.) in which an ITO (indium tin oxide) film having a thickness of 100 nm was formed on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode 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, Baytron PAl4083, Baytron PAl4083) to 70% with pure water is formed by spin coating. Then, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  A chlorobenzene solution of the hole transport material Ha-3 was formed on the first hole transport layer by a spin coating method. Ultraviolet rays were irradiated for 180 seconds, photopolymerization / crosslinking was performed, and a second hole transport layer having a thickness of 40 nm was provided.

  On this 2nd hole transport layer, the host compound 22 and the butyl acetate solution of Ir-12 which is a dopant compound were formed into a film by the spin coat method, and it heat-dried at 120 degreeC for 1 hour, and formed the light emitting layer with a film thickness of 40 nm. Provided.

  On this light emitting layer, the 1-butanol solution of electron transport material ET-23 was formed into a film by the spin coat method, and the 20-nm-thick electron transport layer was provided.

This was attached to a vacuum deposition apparatus, and the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa. Subsequently, lithium fluoride 1.0nm was vapor-deposited as an electron injection layer, and aluminum 110nm was vapor-deposited as a cathode, and the organic EL element 1-3 was produced.

<< Production of Organic EL Elements 1-4 to 1-21 >>
In the production of the organic EL device 1-1, the hole transport material Ha-1, the host compound 1 of the light emitting layer, the dopant compound Ir-12, and the electron transport material ET-23 were replaced with the compounds shown in Table 2 in the same manner. Thus, organic EL elements 1-4 to 1-21 were produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL device, the non-light-emitting surface of each organic EL device after production was covered with a glass case, a glass substrate having a thickness of 300 μm was used as a sealing substrate, and an epoxy-based material was used as a sealing material around it. A photo-curing adhesive (Lux Track LC0629B manufactured by Toagosei Co., Ltd.) is applied, and this is stacked on the cathode and brought into intimate contact with the transparent support substrate. The lighting device as shown in FIGS. 5 and 6 was formed and evaluated.

  Subsequently, the following evaluation was performed.

(External extraction quantum efficiency (also called efficiency))
By lighting the organic EL element under a constant current condition of room temperature (about 23 to 25 ° C.) and ^2.5 mA / cm ² , and measuring the light emission luminance (L) [cd / m ² ] immediately after the start of lighting, The external extraction quantum efficiency (η) was calculated.

  Here, the measurement of light emission luminance was performed using CS-1000 (manufactured by Konica Minolta Sensing), and the external extraction quantum efficiency was expressed as a relative value with the organic EL element 1-1 (comparative example) as 100.

(Drive voltage)
The voltage was measured when the organic EL device was driven under a constant current condition of room temperature (about 23 ° C. to 25 ° C.) and ^2.5 mA / cm ² , and the measurement results are shown below. The organic EL element 1-1 (comparative example) is shown as a relative value of 100.

Voltage = (drive voltage of each element / drive voltage of organic EL element 1-1 (comparative example)) × 100
A smaller value indicates a lower drive voltage for comparison.

(Half life)
According to the measurement method shown below, half-life (simply referred to as life) was evaluated.

The organic EL element was driven at a constant current with a current that gave an initial luminance of 1000 cd / m ² , and a time required to be ½ (500 cd / m ² ) of the initial luminance was obtained. The half life was expressed as a relative value when the comparative organic EL element 1-1 (comparative example) was set to 100.

(Light emission unevenness during continuous driving)
In constant current driving at an initial luminance of 2000 cd / m ² , the luminance after 150 hours was measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing).

20 arbitrary points on the light emitting surface were measured, and from the measured value at this time, light emission unevenness = in-plane minimum luminance / maximum luminance was calculated, and three-level rank evaluation was performed as follows.
◎: Light emission unevenness of 0.96 or more ○: Light emission unevenness of 0.90 or more and less than 0.96 Δ: Light emission unevenness of 0.86 or more and less than 0.90 ×: Light emission unevenness of less than 0.86 Evaluation result and this Table 2 shows the number average molecular weight and molecular weight distribution of the hole transport material used in the inventive sample.

  From the table, the organic EL device of the present invention using the hole transport material according to the present invention exhibits higher luminous efficiency than that of the comparative example, has a long emission lifetime, a low driving voltage, and the time of continuous light emission. It can be seen that the uneven light emission is improved.

Example 2
<< Preparation of Organic EL Element 2-1 >>
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.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by HC Starck Co., Ltd., CLEVIOPVPAI4083) to 70% with pure water, 3000 rpm After forming a thin film by spin coating under the condition of 30 seconds, the film was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 20 nm.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of Ha-2 is put in a molybdenum resistance heating boat, and 200 mg of 21 as a host compound is put in another resistance heating boat made of molybdenum. 200 mg of ET-11 was put into a resistance heating boat made of molybdenum, and 100 mg of Ir-12 as a dopant compound was put into another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

The vacuum chamber was then depressurized to 4 × 10 ⁻⁴ Pa, heated by energizing the heating boat containing Ha-2, vapor-deposited on a transparent support substrate at a vapor deposition rate of 0.1 nm / second, and a second positive electrode of 20 nm. A hole transport layer was provided.

  Further, the heating boat containing the host compound 21 and the dopant compound Ir-12 was energized and heated, and co-deposited on the hole transport layer at a deposition rate of 0.1 nm / second and 0.006 nm / second, respectively. Then, a 40 nm light emitting layer was provided.

  Furthermore, it supplied with electricity to the said heating boat containing ET-11, it heated, and it vapor-deposited on the said light emitting layer with the vapor deposition rate of 0.1 nm / second, 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.

<< Production of Organic EL Elements 2-2 to 2-12 >>
In the production of the organic EL element 2-1, the organic EL element 2 was similarly prepared except that the hole transport material Ha-2, the host compound 21 of the light emitting layer, and the dopant compound Ir-12 were replaced with the compounds shown in Table 3. 2 to 2-12 were produced.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-16 of Example 1, and an illumination device as shown in FIGS. 5 and 6 was formed. Evaluation was performed in the same manner as in Example 1. Efficiency, drive voltage, and lifetime are shown as relative values with the organic EL element 2-1 (comparative example) as 100.

  Table 3 shows the evaluation results.

  From the table, the organic EL device of the present invention using the hole transport material according to the present invention exhibits higher luminous efficiency than that of the comparative example, has a long emission lifetime, a low driving voltage, and the time of continuous light emission. It can be seen that the uneven light emission is improved. It turns out that the organic EL element using the phosphorescence-emitting dopant represented with general formula (2-2a) is excellent especially.

Example 3
<< Production of Organic EL Elements 3-1 to 3-5 >>
In the production of the organic EL device 2-1 of Example 2, the hole transport material Ha-2, the host compound 21 of the light emitting layer, the dopant compound Ir-12, and the electron transport material ET-11 were replaced with the compounds shown in Table 4. Except for the above, organic EL elements 3-1 to 3-5 were produced in the same manner.

<< Calculation of HOMO level of material >>
For the hole transport material and the light emitting host shown in Table 4, the HOMO value was calculated, and the difference between the HOMO value of the hole transport material and the HOMO value of the light emitting host (Δμ = | Value)-(HOMO value of the light emitting host) |). Used with Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002), molecular orbital calculation software manufactured by Gaussian, USA The value of HOMO was B3LYP / 6-31G * as a keyword.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-16 of Example 1, and an illumination device as shown in FIGS. 5 and 6 was formed. Evaluation was performed in the same manner as in Example 1. Efficiency, drive voltage, and lifetime are shown as relative values with the organic EL element 3-1 (comparative example) as 100.

  Table 4 shows the evaluation results.

From the table, there is an organic EL device in which the difference between the HOMO level of the hole transport material represented by the general formula (3-1) and the luminescent host represented by the general formula (1-1) is smaller than 0.5 eV. It turns out that it is excellent.

Example 4
<< Production of Organic EL Elements 4-1 to 4-6 >>
In the production of the organic EL device 1-1 of Example 1, the hole transport material Ha-1, the host compound 22 of the light emitting layer, the dopant compound Ir-12, and the electron transport material ET-23 were replaced with the compounds shown in Table 5. Other than that, the organic EL elements 4-1 to 4-6 were produced in the same manner.

<< Calculation of HOMO level of material >>
The HOMO values were calculated for the light emitting hosts shown in Table 5. As calculated using Gaussian 98 (Gaussian 98, Revision A.11.4, MJ Frisch, et al, Gaussian, Inc., Pittsburgh PA, 2002.), molecular orbital calculation software manufactured by Gaussian, USA. Yes, B3LYP / 6-31G * was used as the keyword for the HOMO value.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-16 of Example 1, and an illumination device as shown in FIGS. 5 and 6 was formed. Evaluation was performed in the same manner as in Example 1. Efficiency, drive voltage, and lifetime are shown as relative values with the organic EL element 4-1 (comparative example) as 100.

  The evaluation results are shown in Table 5.

  From the table, it can be seen that the organic EL device in which the HOMO of the light-emitting host compound represented by the general formula (1-1) is −5.1 eV to −4.3 eV is excellent.

Example 5
In the production of the organic EL device 2-1 of Example 2, the hole transport material Ha-2, the host compound 21 of the light emitting layer, the dopant compound Ir-12, and the electron transport material ET-11 were replaced with the compounds shown in Table 6. Other than that, organic EL elements 5-1 to 5-14 were produced in the same manner.

<< Evaluation of organic EL elements >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL elements 1-1 to 1-16 of Example 1, and an illumination device as shown in FIGS. 5 and 6 was formed. Evaluation was performed in the same manner as in Example 1. Efficiency, drive voltage, and lifetime are shown as relative values with the organic EL element 5-1 (comparative example) as 100.

  The evaluation results are shown in Table 6.

  From the table, it can be seen that the organic EL device using the compound represented by the general formula (1-3) is superior to the light emitting host compound represented by the general formula (1-1).

Example 6
<< Preparation of White Light-Emitting Organic EL Element 6-1 >>
Patterning was performed on a substrate (NAV-45, manufactured by AvanStrate Co., Ltd.) in which an ITO (indium tin oxide) film having a thickness of 100 nm was formed on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode 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, Baytron PAl4083, Baytron PAl4083) to 70% with pure water is formed by spin coating. Then, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  On this first hole transport layer, a chlorobenzene solution of HT-15c was formed by spin coating. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  Next, using a solution obtained by dissolving host compound 28 (100 mg), dopant materials Ir-11 (3 mg) and Ir-14 (3 mg) in 10 ml of toluene, a film was formed by spin coating under the conditions of 2000 rpm and 30 seconds. . The first light emitting layer was formed by vacuum drying at 60 ° C. for 1 hour.

  Further, on this first light emitting layer, a solution obtained by dissolving host compound OC-29 (100 mg) and dopant 1-75 (16 mg) in 6 ml of hexafluoroisopropanol (HFIP) was spin-coated under the conditions of 2000 rpm and 30 seconds. A film was formed by the method, and vacuum-dried at 60 ° C. for 1 hour to form a second light emitting layer.

This substrate is fixed to a substrate holder of a vacuum deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, and then the electron transport material ET-9 is formed on the second light emitting layer as a cathode buffer layer by 30 nm. Lithium fluoride was deposited at 0.5 nm and aluminum was deposited at 110 nm as a cathode to form a cathode, whereby an organic EL element 6-1 was produced.

<< Preparation of White Light-Emitting Organic EL Element 6-2 >>
In the production of the organic EL element 6-1, the host compound 28 of the light emitting layer is 30, the host compound OC-29 is OC-12, the dopant material (1-75) is (1-39), and the electron transport material ET. Organic EL element 6-2 was produced in the same manner except that -9 was replaced with ET-13.

  When the white light-emitting organic EL elements 6-1 and 6-2 were energized, almost white light was obtained, and it was found that the white light-emitting organic EL elements 6-1 and 6-2 could be used as a lighting device. In addition, it turned out that white light emission is obtained similarly even if it replaces with the other compound of illustration.

Example 7
<< Preparation of White Light-Emitting Organic EL Element 7-1 >>
Patterning was performed on a substrate (NAV-45, manufactured by AvanStrate Co., Ltd.) in which an ITO (indium tin oxide) film having a thickness of 100 nm was formed on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode. Thereafter, the transparent support substrate provided with the ITO transparent electrode 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, Baytron PAl4083, Baytron PAl4083) to 70% with pure water is formed by spin coating. Then, it was dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 30 nm.

  On this first hole transport layer, a chlorobenzene solution of HT-15c was formed by spin coating. It heat-dried at 150 degreeC for 1 hour, and provided the 2nd hole transport layer with a film thickness of 40 nm.

  Next, using a solution of 19 (100 mg) as a host and Ir-14 (3 mg), (1-76) (16 mg) as a dopant material Ir-1 (3 mg) in 10 ml of toluene, conditions of 2000 rpm and 30 seconds Below, it formed into a film by the spin coat method. A light emitting layer was formed by vacuum drying at 60 ° C. for 1 hour.

This substrate is fixed to a substrate holder of a vacuum evaporation apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa. Then, the electron transport material ET-26 is 30 nm on the light emitting layer, and then lithium fluoride as a cathode buffer layer. The organic EL element 7-1 was produced by depositing 110 nm of aluminum as a cathode and further depositing 110 nm of aluminum as the cathode.

<< Preparation of white light-emitting organic EL element 7-2 >>
In preparation of the organic EL element 7-1, except that the host compound 19 of the light emitting layer was replaced with 40, the dopant material (1-76) was replaced with (1-84), and the electron transport material ET-26 was replaced with ET-21. Similarly, an organic EL element 7-2 was produced.

  When the white light-emitting organic EL elements 7-1 and 7-2 were energized, almost white light was obtained, and it was found that they could be used as a lighting device. In addition, it turned out that white light emission is obtained similarly even if it replaces with the other compound of illustration.

Example 8
<< Production of White Light-Emitting Organic EL Element 8-1 >>
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 was fixed to a substrate holder of a commercially available vacuum evaporation apparatus, while 200 mg of H-2 was put into a molybdenum resistance heating boat, and 200 mg of 24 as a host compound was put into another molybdenum resistance heating boat. 200 mg of ET-9 is put into a resistance heating boat made of molybdenum, 100 mg of the dopant compound (1-80) is put into another resistance heating boat made of molybdenum, and Ir-14 which is a dopant compound is put into another resistance heating boat made of molybdenum. 100 mg was placed and attached to a vacuum deposition apparatus.

Next, after the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, each of the heating boats containing H-2 was separately energized, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / second. A hole transport layer was provided.

  Further, the host compound 24 and the dopant compound (1-80) are energized to the heating boat containing the dopant compound Ir-14, and the host compound 24 and the dopant compound (1-80) and The deposition rate of Ir-14 was adjusted to be 100: 5: 0.6, vapor deposition was performed to a thickness of 30 nm, and a light emitting layer was provided.

  Furthermore, it supplied with electricity to the said heating boat containing ET-9, it heated, and it vapor-deposited on the said light emitting layer with the 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 8-1 was produced.

<< Preparation of white light-emitting organic EL element 8-2 >>
In preparation of the organic EL element 8-1, except that the host compound 24 of the light emitting layer was replaced with 42, the dopant material (1-80) was replaced with (1-89), and the electron transport material ET-9 was replaced with ET-22. Similarly, an organic EL element 8-2 was produced.

  When the white light emitting organic EL elements 8-1 and 8-2 were energized, almost white light was obtained, and it was found that the white light emitting organic EL elements 8-1 and 8-2 could be used as a lighting device. In addition, it turned out that white light emission is obtained similarly even if it replaces with the other compound of illustration.

Example 9
(Blue light emitting organic EL device)
The organic EL element 2-4 produced in Example 2 was used as a blue light-emitting organic EL element.

(Green light-emitting organic EL device)
As a green light-emitting organic EL element, a blue element light-emitting organic EL element 2-4B was prepared in the same manner as in the production of the organic EL element 2-4 prepared in Example 2, except that (1-8) was changed to Ir-1. Was made.

(Red light emitting organic EL device)
As a red light-emitting organic EL element, a red light-emitting organic EL element 2-4C was prepared in the same manner as in the production of the organic EL element 1-4 of Example 2, except that (1-8) was changed to Ir-14. .

  The above red, green and blue light emitting organic EL elements are juxtaposed on the same substrate to produce an active matrix type full color display device having the form shown in FIG. 1, and FIG. 2 shows a display portion of the produced display device. Only the schematic diagram of A is shown. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) 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 not shown). The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. Thus, a full color display device was produced by juxtaposing the red, green, and blue pixels appropriately.

  It was confirmed that by driving the full-color display device, a full-color moving image display with high light emission efficiency and a long light emission life can be obtained.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power supply line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with a transparent electrode 108 Nitrogen gas 109 Water catching agent

Claims (9)

The anode and cathode have a hole transport layer and a light emitting layer, and at least one of the light emitting layers contains a compound represented by the following general formula ( 1-2 ) and a phosphorescent dopant. And the organic electroluminescent element characterized by containing the compound represented by the following general formula (3-1) in the said positive hole transport layer.

(In the formula, Ra, Rb, and R _{1 to} R ₁₄ each independently represent a hydrogen atom , a substituent that does not include a 9-carbazolyl group, or a substituent that does not include a diphenylamino group .)

_(Wherein, Z 1 to Z ₅ represents an integer of 1-5 .n1 represents a hydrogen atom or a substituent, n2, n3 represents an integer of 1 to 4, n represents an integer of 4 or more.) The anode and the cathode have a hole transport layer and a light emitting layer, and at least one layer of the light emitting layer contains a compound represented by the following general formula (1-3) and a phosphorescent dopant. And the organic electroluminescent element characterized by containing the compound represented by the following general formula (3-1) in the said positive hole transport layer.

(In the formula, Rc, Rd, Re, and R _{1 to} R ₁₄ each independently represent a hydrogen atom or a substituent.)

_(Wherein, Z 1 to Z ₅ represents an integer of 1-5 .n1 represents a hydrogen atom or a substituent, n2, n3 represents an integer of 1 to 4, n represents an integer of 4 or more.) The organic electroluminescent device according to claim 1 or 2, wherein the phosphorescent dopant is represented by the following general formula (2-2).

(In the formula, R ′ _{1 to} R ′ ₄ and R′a to R′c each independently represent a hydrogen atom or a substituent. M1 represents an integer of 1 to 3, and m2 represents an integer of 0 to 2. M1 + m2 is 3. Ya-L ₁ -Yb represents a bidentate ligand, Ya and Yb each independently represent a carbon atom, a nitrogen atom, or an oxygen atom, and L ₁ together with Ya and Yb Represents an atomic group forming a bidentate ligand, and M represents a group 8-10 transition metal in the periodic table. The organic electroluminescent device of claim 1, wherein said phosphorescent dopant is represented by the following general formula (2-3).

(In the formula, R ′ _{1 to} R ′ ₄ and R′a to R′c each independently represent a hydrogen atom or a substituent. M1 represents an integer of 1 to 3, and m2 represents an integer of 0 to 2. M1 + m2 is 3. Ya-L ₁ -Yb represents a bidentate ligand, Ya and Yb each independently represent a carbon atom, a nitrogen atom, or an oxygen atom, and L ₁ together with Ya and Yb Represents an atomic group forming a bidentate ligand, and M represents a group 8-10 transition metal in the periodic table. At least one of Ra, Rb or R _{1 to} R _{14 in} the general formula (1-2), or Rc, Rd, Re, or R _{1 to} R _{14 in} the general formula (1-3) is substituted or unsubstituted. the organic electroluminescent device according to any one of claims 1 to 4, characterized in that the dibenzofuryl group or dibenzothienyl groups. Wherein Ra or Rb of general formula (1-2), or, wherein Rc of the general formula (1-3), at least one of Rd or Re is, that it is a substituted or unsubstituted dibenzo furyl group or a dibenzothienyl group the organic electroluminescent device according to any one of claims 1 to 5, wherein. Difference the HOMO level of the general formula (1 2) or the compound represented by Formula HOMO level and the formula of the compound represented by (1-3) (3-1) 0.5 It is smaller than eV , The organic electroluminescent element of any one of Claims 1-6 characterized by the above-mentioned. Display apparatus comprising the organic electroluminescent element of any one of claims 1-7. Lighting apparatus comprising the organic electroluminescent element of any one of claims 1-7.

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