JP6048281B2 - Organic electroluminescence element, lighting device and display device - Google Patents

Description

The present invention, organic electroluminescent device, a lighting device and a display device.

  An organic electroluminescence element (hereinafter also referred to as “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 is injected from the anode by applying an electric field. Excitons are generated by recombining the injected holes and electrons injected from the cathode in the light-emitting layer, and light emission (fluorescence / phosphorescence) is used when the excitons are deactivated. It is a light emitting element. The organic EL element is an all-solid-state element composed of an organic material film having a thickness of only a submicron between the electrodes, and can emit light at a voltage of several volts to several tens of volts. It is expected to be used for next-generation flat display and lighting.

  As for development of organic EL elements for practical use, Princeton University has reported organic EL elements that use phosphorescence emission from excited triplets (see, for example, Non-Patent Document 1), and since then phosphorescence at room temperature. The research of the material which shows is becoming active (for example, refer patent document 1 and nonpatent literature 1).

  Expressing the color tone according to the application by changing the structure of such a phosphorescent compound is described in J. Org. Am. Chem. Soc. 107, page 1431 (1985), a trisphenylpyridine iridium complex described in J. Am. Am. Chem. Soc. 125, page 12971 (2003), a trisphenylisoquinoline iridium complex, Chem. Mater. , 18, 5119 (2006), phosphorescent complexes that emit light in B (blue), G (green) and R (red) colors have already been found. Yes.

  These phosphorescent complexes have their own emission spectra due to the difference in structure, but in many cases the spectrum becomes longer and broader due to aggregation and crystallization of the complex itself, and the original emission color. There is a problem that often cannot be obtained. For this reason, it is often used together with a binder or coexisting with a host compound, but the improvement effect is not sufficient, and the variation in color tone is remarkable under energization and high temperature storage.

  The fundamental cause of aggregation and crystallization of this phosphorescent complex is the strength of the interaction energy of the phosphorescent complex itself, and the presence state in the film due to the interaction balance with the coexisting host compound. However, the biggest factor is that it changes over time.

  As means for solving this problem, the state of the film immediately after the formation is stabilized, that is, the Gibbs free energy is increased negatively, so that the change in the state of the film can be suppressed.

  Gibbs' free energy is determined by enthalpy and entropy according to the second law of thermodynamics, but enthalpy cannot be improved universally because the chemical structure unique to the complex molecule is the dominant factor. Since entropy is determined by the number and distribution of components, it should be possible to use it as a universal technical variation factor.

  It is reasonable to explain this from the entropy effect.

  This will be described with reference to the drawings. FIG. 1 is a schematic diagram for explaining that entropy is increased by mixing two components. FIG. 1A shows a mixed model of component A and component B. FIG. 1B is a mixed model of components A.

Gibbs free energy change (ΔG) in the reaction at a constant pressure and low temperature has the following relationship with enthalpy change (ΔH) and entropy change (ΔS). T represents an absolute temperature.
Expression (1) ΔG = ΔH−TΔS
For example, it is assumed that 2n phosphorescent organometallic complexes (component A) exist in a certain film. Suppose that the film initially contains half the number of n complexes, and later n identical complexes (component A) are added to increase the volume to 2n and double the volume. At this time, since the types of the complexes are the same, the amount of change in entropy is zero (FIG. 1B). On the other hand, if n added later are different complexes (component B), the first complex (component A) is mixed with a different complex (component B), so the entropy increases (FIG. 1 ( A)). This increase is the entropy effect, and the Gibbs free energy shifts to the minus side, that is, to the stable side, and as a result, the film becomes stable and the change in state over time is reduced as a basic principle. is there.

  This “different complex” makes it possible to effectively suppress complex aggregation over time, both from the viewpoint of film stability due to the entropy effect and interactive inactivation of the π plane.

  The same can be said for not only the film but also the complex solution. That is, it is considered that a schematic diagram of a solution in which an isomer mixed complex is completely dissolved in a solvent, that is, in an isolated dispersion state, corresponds to the right diagram in FIG. The free energy of Gibbs of these solutions or thin films is negatively larger than that of a complex solution or powder composed of a single substance (corresponding to the right diagram in FIG. 1A), and fluctuation due to disturbance is reduced. That is, it can be interpreted that aggregation and recrystallization hardly occur.

  Due to this effect, the dispersibility of the complex when the film is formed using a solution and the variability of the formed film over time and after energization are suppressed, and the sublimation property of the complex during sublimation purification and vapor deposition is improved. Sublimation in the molecular state is possible, thereby forming a complex dispersion film close to an ideal isolated dispersion state.

  In order to increase the entropy as described above, it is effective to allow a plurality of types of luminescent complexes to coexist. However, when complexes with different electronic states coexist, the injection of electrons and holes (collectively called charge carriers) differs depending on the type of molecule, so charge injection is given priority to the most likely complex molecules. As a result, it has been found that the recombination probability of charges is lowered and the light emission efficiency is lowered, the luminance is lowered with the lapse of time of light emission, and the so-called light emission lifetime is shortened.

  To solve the above problem, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels are substantially the same, and the emission spectrum and physical properties are very similar. In terms of structure, it is necessary to mix as many compound molecules as possible.

  In order to achieve this, a so-called heteroleptic complex (for example, see Patent Document 2) in which a part of a plurality of ligands forming a complex is a ligand having a different structure, is symmetric. Although the crystallinity due to the property is relaxed and the growth of coarse crystals in the organic EL device is improved, a π plane that promotes the interaction between the complexes often remains on the outermost part of the complex It does not lead to prevention of cohesion.

US Pat. No. 6,097,147 US Patent Application Publication No. 2011/0057559

M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000)

The present invention has been made in view of the above problems or situation, the problem to be solved is, the physical properties, Isomers mixed metal complex compositions that contain a plurality of atropisomers energy level is very close Is used as an organic electroluminescence device material to improve the stability of the organic metal complex film over time, and the organic electroluminescence device has a small rate of change in resistance value of the light emitting layer and a small rate of change in half width of the emission spectrum. Is to provide. Furthermore, it is providing the illuminating device and display apparatus using the said organic electroluminescent element.

  In order to solve the above-mentioned problems, the present inventor made the organic metal complex having substantially the same or very similar energy coexisting in a plurality of types of thin films in the process of studying the cause of the above-mentioned problem. As the entropy effect increases, Gibbs' free energy increases negatively, so that a thin film stabilization technology that reduces the change in physical properties of the thin film over time is found, and this technology can be applied to organic EL. Proved.

  Furthermore, the energy level is inevitably approximated when the organometallic complex is made into a plurality of atropisomers and diastereoisomer components, and a plurality of isomer mixture metal complexes can be synthesized by a single synthesis and generation operation. From the viewpoint of production of the complex, the present inventors have found it suitable, and have reached the present invention.

  That is, the said subject which concerns on this invention is solved by the following means.

1. An organic electroluminescence device comprising a pair of electrodes and one or a plurality of organic layers including a light emitting layer between the pair of electrodes,
The light-emitting layer contains a phosphorescent organic electroluminescence light-emitting material that is an isomer mixed metal complex composition composed of a metal atom and a plurality of ligands, and the plurality of ligands are: A ligand having the same structure or a different ligand,
In the isomer mixed metal complex composition, at least one of the plurality of ligands has an aromatic ring as a substituent, and free rotation of a bond axis between the aromatic ring and the ligand is the metal atom. An organic electroluminescence device comprising a mixture of atropisomers formed by the fact that free rotation cannot be performed due to the influence of other ligands in the complex molecule due to the complex formation between the ligand and the ligand .

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

(In the formula, ring Am, ring An, ring Bm and ring Bn represent a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle, and further , an alkyl group, cycloalkyl as a substituent. Group, alkenyl group, alkynyl group, aromatic hydrocarbon ring group, aromatic heterocyclic group, heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, Aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or heteroarylsulfonyl group, amino group, halogen atom, fluorohydrocarbon group , cyano group, nitro group, hydroxy group, optionally having a mercapto group good . Ring Am, Bm, _Xm 1 in An and _{Bn, Xm 2, Xm 3,} Xm 4 and _{Xm 5, Xn 1, Xn 2} , Xn 3, Xn 4 and Xn _5, respectively, a carbon atom or a nitrogen atom Represent.

When Xm ₁ and M and Xn ₁ and M each form a coordination bond, Xm ₄ and M and Xn ₄ and M each form a covalent bond,
When Xm ₁ and M and Xn ₁ and M each form a covalent bond, Xm ₄ and M and Xn ₄ and M each form a coordinate bond.
However, Xn ₁ and Xn ₄ or Xm ₁ and Xm ₄ do not represent a carbon atom at the same time.

Ar ^m and Ar ⁿ represent an aromatic hydrocarbon ring group or an aromatic heterocyclic group in which the bond axis to ring Bm or ring Bn does not have a symmetry axis, and a halogen atom, a cyano group, an alkyl group, It may have an alkenyl group, an alkynyl group, an alkoxy group, an amino group, an arylalkyl group, an aryl group, a heteroaryl group, a non-aromatic hydrocarbon group or a non-aromatic heterocyclic group . M represents iridium or platinum. m and n represent an integer of 0 to 3, and m + n is 2 or 3. )
3 . In the said General formula (1), the ring Bm, the ring Bn or the ring Am, and the ring An represent an imidazole ring or a pyrazole ring, The organic electroluminescent element of the 2nd item | term characterized by the above-mentioned.

4). In the general formula (1), a ligand formed by combining ring An and ring Bn, or a ligand formed by combining ring Am and ring Bm is represented by the following general formula (2). The organic electroluminescence device according to the second or third item, which is represented by any one of the general formula (3), the general formula (5), and the general formula (6).

(Wherein, R _5a1 and R _5a2 each independently, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aromatic hydrocarbon ring group, aromatic It represents a heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent, and p represents an integer of 0 to 4.

R _5b1 , R _5b2 and R _{5c1 each} represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and further has a substituent. May be. X _5a and X _5b each independently represent ═C (R _5e ) — or _═N— . R _5e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.

Ar ₅₁ and Ar ₅₂ each independently represent an aromatic hydrocarbon ring group represented by the general formula (4).

R ₈₁ to R ₈₅ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aryl group, a heteroaryl group, a non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. Two adjacent groups of R _{81 to} R ₈₅ may be bonded to each other to form a ring. However, R ₈₁ = R ₈₅ and R ₈₂ = R ₈₄ are not _satisfied .

  * In general formula (2) and (3) represents the site | part which forms a bond with a metal atom.

In the general formula (5) and general formula _{(6), R 6a1} and _{R 6a2} each independently, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, It represents an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. q represents an integer of 0 to 4.

R _6b1 , R _6c1 , R _6b2 , R _6c2 and R _6d2 each independently represent a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. X _6a and X _6b each independently represent ═C (R _6e ) — or _═N— . R _6e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
* In General formula (5) and General formula (6) represents the site | part which forms a bond with an iridium atom.

Ar ₆₁ and Ar ₆₂ are synonymous with Ar ₅₁ and Ar ₅₂ in General Formula (2) and General Formula (3), and represent an aromatic hydrocarbon group represented by General Formula (4).

* In General formula (5) and General formula (6) represents the site | part which forms a bond with a metal atom. )
5 . Said M represents an iridium atom, The organic electroluminescent element as described in any one of Claim 2 to 4 characterized by the above-mentioned.

6 . The light emitting layer contains a mixture of the light emitting material for organic electroluminescence and a host compound having a biaryl structure that can freely rotate, or any one of items 1 to 5 , The organic electroluminescent element of description.

7 . 7. The organic electroluminescence device according to item 6, wherein the host compound having a biaryl structure capable of freely rotating is a compound having a dibenzofuran structure.

8 . 7. The organic electroluminescence device according to item 6, wherein the host compound having a biaryl structure capable of freely rotating is a compound having a carbazole structure.

9 . 7. The organic electroluminescence device according to item 6, wherein the host compound having a biaryl structure capable of free rotation is a compound having an unsubstituted phenyl group.

10 . An organic electroluminescence device according to any one of items 1 to 9 is provided.
11 . A display device comprising the organic electroluminescence element according to any one of items 1 to 9 .

By the means of the present invention, physical properties, using the isomeric mixture metal complex compositions energy level contains a plurality of atropisomers were very similar as organic electroluminescent device material, with time of an organometallic complex It is possible to provide an organic electroluminescence device in which the stability of the film is improved, the change rate of the resistance value of the light emitting layer is small, and the change rate of the half width of the emission spectrum is small. Furthermore, a lighting device and a display device using the organic electroluminescence element can be provided.

  The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

  Due to the atropisomeric axis in the present invention, physical properties, electronic states represented by HOMO and LUMO, and the presence of a plurality of isomers with very close emission spectra can coexist without causing deterioration of the emission lifetime due to the entropy effect. It is considered that the solubility in the solvent and the interaction due to the π-plane of the aromatic ring in the complex molecule are suppressed, and the stability of the dispersion state of the complex is improved.

Schematic diagram for explaining that entropy increases by mixing two components Schematic diagram showing an example of a display device composed of organic EL elements Schematic diagram of display section A in FIG. Pixel circuit diagram Schematic diagram of passive matrix type full color display device Schematic of lighting device Schematic diagram of lighting device High-performance liquid chromatography measurement chart

The organic electroluminescence device of the present invention is an organic electroluminescence device comprising a pair of electrodes of an organic electroluminescence device and one or a plurality of organic layers including a light emitting layer between the pair of electrodes,
The light-emitting layer contains a phosphorescent organic electroluminescence light-emitting material that is an isomer mixed metal complex composition composed of a metal atom and a plurality of ligands, and the plurality of ligands are: A ligand having the same structure or a different ligand,
In the isomer mixed metal complex composition, at least one of the plurality of ligands has an aromatic ring as a substituent, and free rotation of a bond axis between the aromatic ring and the ligand is the metal atom. It is characterized in that it contains a mixture of atropisomers produced by the fact that free rotation cannot be performed due to the influence of other ligands in the complex molecule due to the complex formation between the complex and the ligand. This feature is a technical feature common to the inventions according to claims 1 to 11 .

  Furthermore, in the present invention, the atropisomer is preferably a metal complex composition for organic electroluminescence represented by the general formula (1). Moreover, in the said General formula (1), it is preferable that the ring Bm, the ring Bn, the ring Am, and the ring An represent an imidazole ring or a pyrazole ring.

  In the general formula (1), a ligand formed by combining the ring An and the ring Bn or a ligand formed by combining the ring Am and the ring Bm is represented by the general formula (2). ), General formula (3), general formula (5), or general formula (6). Moreover, it is preferable that M represents an iridium atom in order to contain many atropisomers and / or diastereomeric isomers.

The light emitting layer preferably contains a mixture of the light emitting material for organic electroluminescence and a host compound having a biaryl structure that can freely rotate. The host compound having a biaryl structure capable of freely rotating is preferably a compound having a dibenzofuran structure, a compound having a carbazole structure, or a compound having an unsubstituted phenyl group.

  The organic EL element of the present invention can be suitably included in a lighting device and a display device.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

  The present invention will be described below.

  First, enantiomers (enantiomers) and diastereomers will be described in detail.

  As described above, the main type that exhibits chirality is the most common carbon atom (or an atom such as nitrogen, sulfur, or phosphorus having an unpaired electron) substituted with four different substituents. Asymmetric carbon compound (I), molecule having a bond axis (atrop isomerism axis) imparting rotational isomerism such as biaryl group having a bulky substituent at ortho position, so-called axially asymmetric compound (II), aromatic ring Surface asymmetric compound (III) that appears due to the fact that its surface cannot be fixed or freely rotated, helicity compound (IV) that defines the direction of torsion, such as helicene, and also forms a complex (not shown) Thus, compounds that exhibit non-objectivity in a mirror image are also within the scope of the present invention.

  Enantiomers, also known as enantiomers, are isomers that appear when mirrored like the relationship between the right and left hands, and are not only asymmetric carbon compounds, but also as described below [II] This also applies to the types of [III] and [IV] and other chirality-expressing substances, which are similarly mirror images of each other, and can also be referred to as enantiomeric relationships.

  On the other hand, a diastereomer is a molecule that appears when there are two or more sites that exhibit chirality, but is not a mirror image but has the same title when writing a planar molecular structure. Can also be called a diastereomeric relationship. Specific examples of the compound having three asymmetric carbons are shown below. There are eight types of isomers in this molecule, of which four pairs in mirror image relation are enantiomer isomers, and the others are diastereomeric isomers. Solid arrows indicate the enantiomeric relationship. Dashed double arrows indicate diastereomeric relationships.

  Furthermore, specific examples of the compounds each having one axial asymmetric and one asymmetric carbon are shown below. Thus, any type of chirality can be used in combination. Solid arrows indicate the enantiomeric relationship. Dashed double arrows indicate diastereomeric relationships.

  In addition, in a complex having a plurality of ligands, such as a trivalent hexacoordinate iridium complex, if one ligand has chirality, the resulting complex has a plurality of chiralities. , Thereby also expressing diastereomeric isomers.

When there are n sites where chirality is expressed, there are generally 2 ⁿ isomers. The type of site where the chirality is expressed is arbitrary. For example, there are 8 isomers from a compound with 3 sites where chirality is expressed, and 16 isomers from a compound with 4 sites where chirality is expressed.

  The atropisomer in the present invention is the same complex of an aryl group substituted with a ligand skeleton bonded to the metal forming the metal complex and the ligand skeleton in the ligand forming the metal complex. A stereoisomer that cannot be rotated due to steric hindrance or interaction with another ligand in the molecule.

  Next, the technical idea of the present invention will be described.

  Scheme 1 below shows an orthometalated complex in which two bidentate ligands are coordinated to a metal atom having a coordination number of 4 as a schematic diagram of the orthometalated complex. The ligand consists of two aromatic rings Ar-A and aromatic ring Ar-B, which are linked via the linking group (L) or directly.

  Next, a complex that forms atropisomerism when the complex of the present invention is formed will be described with reference to Scheme 2. As shown in Scheme 2, in the present invention, in the state of the ligand before forming the complex, the aromatic rings Ar-A and Ar-B, which are partial structures forming the complex, are further linked via a single bond capable of free rotation. (Ar-C)) is substituted. As a result of the complex formation of this ligand with a metal ion, free rotation is not possible due to the influence of the other ligand (Ar-A in the scheme) that forms the complex molecule, not the influence of the ligand itself. To form an atropisomeric axis.

  In this complex, the Ar-C π plane loses free rotation due to the effect of Ar-A (steric shielding effect (repulsive force) and / or association effect (attraction) by π-π stack and dipole / dipole)). As a result, it was found that at least one π plane was inactivated interactively and could effectively prevent aggregation.

  In Scheme 2, the bond between Ar—B and Ar—C cannot be freely rotated due to complex formation, which becomes a driving force (A) and an atropisomeric axis is formed, but the aromatic ring Ar—C is aromatic. The present invention also includes those in which a bond between the ring Ar-A and the bond between Ar-B and Ar-C cannot be freely rotated by complex formation and an atropisomeric axis is formed.

  The complex of the present invention, in which the center of the body is formed of a tetracoordinate metal, will be further described using the following scheme 3. Specifically, enantiomers and diastereomers composed of atropisomeric axes in the case of a tetracoordinate metal will be described. Since the complex of the present invention shown in Scheme 3 cannot freely rotate the bond between Ar—B and Ar—C, two enantiomers are generated per ligand. These enantiomers are therefore mirror images of each other and cannot be superimposed. Two enantiomers are generated with respect to the bond axis C1 in which one ligand cannot freely rotate. Let this be 1R body and 1S body. Similarly, two types of enantiomers are formed even with respect to the bond axis C2 in which the other ligand cannot freely rotate. Let this be 2R, 2S. Since there are two enantiomers for each ligand, there are 2 × 2 = 4 stereoisomers. Of these, those that are mirror images of each other and cannot be superposed are enantiomers, and those that are not mirror images and cannot be superposed are diastereomers, each having two types. Solid arrows indicate the enantiomeric relationship. Dashed double arrows indicate diastereomeric relationships.

A planar square complex having a metal M having a coordination number of 4 (for example, Pt (II)), a general composition M (AB) ₂ in which a bidentate ligand is ligand, wherein AB is “Cis / trans isomers” are present.

Cis isomerism means that in the complex of composition (AB) ₂ two A groups and two B groups are both at adjacent corners of a square. Both the A group and the two B groups are at two opposite corners of each square. For the definition of cis / trans-isomers in planar square metal complexes, see, for example, J. Org. Huhey, E .; Keiter, R, Keiter, Anorganische Chemie: Prinzipien von Struktur und Reaktivitaet, 2nd, newly revised edition, translated into German and expanded by Ralf Steudel, Berlin; New York: its description is described in de Gruyter, 1995, pages 557 to 559 ing.

  In general, it is known that cis / trans isomers have different physical properties such as emission spectrum and compound stability, and electronic states are often different. Excluded from the concept of body. The stability of the cis / trans isomer varies depending on the type of ligand, and it is assumed that in the tetradentate square metal complex, the complex corresponding to the present invention is either cis / trans.

Next, the complex of the present invention which is formed of a metal with a hexacoordinate at the center is further described. In the case of a complex with a metal M having a coordination number of 6 (ie, an octahedral complex), for example, an Ir (III) complex, the complex is of the general composition M (AB) ₃ (where AB is a bidentate ligand. ), There is an isomer represented by a facial form (fac-form) and a meridional form (mer-form).

  For the definition of cis / trans isomer and fac− / mer− isomer in octahedral metal complexes, see, for example, J. Am. Huhey, E .; Keiter, R.A. Keiter, Anorganische Chemie: Prinzipien von Structur und Reaktivitaet [Inorganic Chemistry: Principles of Structure and Reactivity], 2nd, newly revised edition, translated into German and expanded by Ralf Steudel, Berlin; New York: to de Gruyter, 1995, pages 575to 576 The explanation is described.

  In general, it is known that facial / meridional isomers have different physical properties such as emission spectrum and compound stability, and electronic states are often different, and the isomers of the isomer complex mixture composition of the present invention Exclude from concept. In addition, since the facial body is thermodynamically more stable than the meridional body, it is assumed that all the complexes corresponding to the present invention are facial bodies in the hexadentate octahedral metal complex.

  Furthermore, the octahedral complex with a bidentate ligand coordinated has a mirror image relationship of Δ (delta) and Λ (lambda) (corresponding to clockwise and counterclockwise propellers). Enantiomers exist.

  Next, the complex of the present invention and consisting of a metal having a six-coordinate center is further described using the following scheme 4. In the case where the central metal is a hexacoordinate metal complex, a metal exists at the center of the regular octahedron, and forms a three-dimensional structure in which atoms coordinated at each vertex are arranged.

  Although difficult to understand in Scheme 4, the Ar—C ′ plane in the ligand when the complex is formed approaches the Ar—B plane of the other ligand in the same complex molecule, so that Ar—B ′ and The free rotation of the bond between Ar and C ′ becomes impossible. There are two diastereomers for a bond that cannot rotate freely in one ligand, as in the case of a complex in which the central metal is a tetracoordinate. A complex composed of a metal with a hexacoordinate at the center has three ligands, so there are 2 × 2 × 2 = 8 kinds of diastereomers and enantiomers.

  Furthermore, there are two types of complexes, Λ (lambda) and Δ (delta), which occur in complexes in which a bidentate ligand is coordinated to a 6-coordinated metal, so the total number of isomers is 16 and 4 The effect of increasing the entropy described above is greater than in the case of the coordination metal complex, that is, the effect of stabilizing the film state is greater. For this reason, it is preferable that the center metal of the complex of the present invention is Ir. Solid arrows indicate the enantiomeric relationship.

  Since the technical idea and basic principle of the present invention are as described above, the effect is greater when there are three or four atropisomeric axes than two, and in the case of hexadentate coordination such as an iridium complex. The effect is likely to be exerted even in the case of a heteroleptic complex in which one of the three ligands has a different chemical structure.

  On the other hand, a complex using a ligand having an atropisomeric axis is already known at the ligand stage, such as the ligand and complex shown in Scheme 5. For example, the ligand used for the exemplary compound (170) in International Publication No. 2007/097149 is such that the imidazole ring is Ar-B, the phenyl group at the 2-position of the imidazole ring is Ar-A in Scheme 4, and imidazole. A 2-phenyl-6-methylphenyl group substituted at the 1-position of the ring corresponds to Ar-D. In this ligand, the single bond between the 1-position and the phenyl group substituted on the 1-position of imidazole cannot rotate freely, and there is an atropisomer. In this case, however, Ar-D, which controls atropisomerism, cannot rotate freely with Ar-B due to the effect of steric hindrance from the ligand stage, and free rotation is inhibited by forming a complex. Since it has not come to be, it is a complex different from the present invention.

  In such a complex, the Ar-D plane protrudes outward from the center of the complex molecule, and can approach a plane that forms an aromatic ring of another complex molecule. As described above, this is insufficient to alleviate the cohesiveness of the complex itself, and depending on the chemical structure, rather, it promotes positive interaction between Ar-D portions, that is, aggregation. It is greatly inferior to the complex of the present invention in terms of stability and solubility of the film state.

  The ligand used for the exemplary compound (170) described in International Publication No. 2007/097149 is shown below.

  On the other hand, since the complex of the present invention is close to the skeleton ligand portion forming the complex and the aryl group as a substituent, the interaction with the π plane of the aromatic ring with other complex molecules is suppressed, By preventing the aggregation and making a mixture of enantiomers and diastereomers, the stability and solubility of the film state are excellent.

  In addition, it is a fact that known complex documents that may satisfy the requirements of the present invention are described in known patent documents and technical papers. For example, in Japanese Patent Application Publication No. 2011-500634, the atropisomeric axis is constructed at the time of complex formation from its chemical structure, and there are two or more axes, and there is no specific description in the specification. Although it may be associated with the inclusion of isomers, the specification in which the compound is described does not describe any active use of the enantiomeric and diastereomeric mixtures of the complex. It can be said that it is completely different from the technical idea.

  Further, the invention content of the patent document can be interpreted that a simple compound described on paper can improve the light emission life and color tone in an organic EL device, and from this point of view, the invention is completely different from the present application. That is clear.

  JP-T-2008-525995 discloses an organic electronic device using an atropisomer produced by inhibiting free rotation of a carbon-carbon bond. The described atropisomer is a fluorescent material having anthracene, pyrene or chrysene as the main skeleton, and there is no disclosure of the phosphorescent transition metal complex of the present invention. It is clear that the physical properties of the produced isomers are greatly different (describing the syn form and the anti form in the patent document), the preferred isomers are excessive, and the technical idea is different from the present invention. .

  In the complex of the present invention, the aromatic ring substituted on the complex skeleton needs to be an aromatic ring having no axis of symmetry.

  An aromatic ring having no symmetry axis means one that is not in the same shape when rotated 180 degrees along the bond axis with the complex skeleton. That is, it does not have a two-fold rotational symmetry axis.

  The following description will be made with respect to a 3-tolyl group and a 3,5-xylyl group. In the case of a 3-tolyl group, it is not the same shape when rotated 180 degrees along the bond axis with the complex skeleton, but in the case of a 3,5-xylyl group, it is rotated 180 degrees along the bond axis with the complex skeleton. When it does, it becomes the same form.

  Thus, it is a partial structure that cannot rotate due to complex formation and requires an aromatic ring having no axis of symmetry in order to express the atropisomerism of the present invention.

As the orthometalated complex (isomer mixed metal complex composition) that forms an atropisomeric axis at the time of complex formation of the present invention, one having a structure represented by the general formula (1) is preferable.

In the formula, ring Am, ring An, ring Bm and ring Bn represent a 5-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle, and further, as a substituent , an alkyl group, a cycloalkyl group , Alkenyl group, alkynyl group, aromatic hydrocarbon ring group, aromatic heterocyclic group, heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, aryl Oxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or heteroarylsulfonyl group, amino group, halogen atom, fluorohydrocarbon group, cyano group, nitro group, hydroxy group, it may also have a mercapto group . Xm ₁ , Xm ₂ , Xm ₃ , Xm ₄ and Xm ₅ in the rings Am and Bm each represent a carbon atom or a nitrogen atom. Xn ₁ , Xn ₂ , Xn ₃ , Xn ₄ and Xn ₅ in ring An and ring Bn each represent a carbon atom or a nitrogen atom.
When Xm ₁ and M and Xn ₁ and M each form a coordination bond, Xm ₄ and M and Xn ₄ and M each form a covalent bond,
When Xm ₁ and M and Xn ₁ and M each form a covalent bond, Xm ₄ and M and Xn ₄ and M each form a coordinate bond.
However, Xn ₁ and Xn ₄ or Xm ₁ and Xm ₄ are not simultaneously carbon atoms.

Ar ^m and Ar ⁿ represent an aromatic hydrocarbon ring group or an aromatic heterocyclic group whose bond axis to the substituent does not have a symmetry axis, and further a halogen atom, cyano group, alkyl group, alkenyl group as a substituent , An alkynyl group, an alkoxy group, an amino group, an arylalkyl group, an aryl group, a heteroaryl group, a non-aromatic hydrocarbon group or a non-aromatic heterocyclic group . M represents Ir or Pt.

  m and n represent an integer of 0 to 3, and m + n is 2 or 3.

  In general formula (1) and general formula (2), as ring Am, ring An, ring Bm, 5-membered aromatic heterocyclic ring represented by ring Bn, 6-membered aromatic hydrocarbon ring or aromatic heterocyclic ring For example, benzene ring, oxazole ring, oxadiazole ring, thiophene ring, thiazole ring, isothiazole ring, thiadiazole ring, furan ring, pyrrole ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, diazine ring, triazine ring, Examples include an imidazole ring, a pyrazole ring, a triazole ring, and a tetrazole ring.

  Hereinafter, examples of 5-membered or 6-membered aromatic hydrocarbon rings or aromatic heterocycles represented by Am, An, ring Bm, and ring Bn are represented by the following general formulas A-1 to A-53, B-1 to B. Although shown by -13, this invention is not limited to these.

  In the general formulas A-1 to A-53 and B-1 to B-13, * indicates a portion where a bond is formed with the transition metal element M.

In the above general formulas A-1 to A-53, RA ₁ , RA ₂ , RA ₃ and RA ₄ each represent a hydrogen atom or a substituent, and the substituent includes an alkyl group (for example, a methyl group, an ethyl group, Group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (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 carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl Fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzimidazolyl group, pyrazolyl group, pyrazinyl group, Triazolyl group (for example, 1,2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group , Furazanyl group, thienyl group, quinolyl group, benzofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (which constitutes the carboline ring of the carbolinyl group) One of the carbon atoms is a nitrogen atom Quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxy group (eg, methoxy) Group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (for example, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (for example, phenoxy) Group, naphthyloxy group, etc.), alkylthio group (eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, Chlorohexyl group, etc.), arylthio group (eg, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group) Etc.), aryloxycarbonyl groups (eg, phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl groups (eg, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group) Cyclohexylaminosulfonyl group, octylaminosulfonyl group, dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylamino Sulfonyl group, etc.), acyl group (for example, acetyl group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group) , Pyridylcarbonyl group etc.), acyloxy group (eg acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group etc.), amide group (eg methylcarbonyl) Amino group, ethylcarbonylamino group, dimethylcarbonylamino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethyl Hexylcarbonylamino group, octylcarbonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group) Pentylaminocarbonyl group, cyclohexylaminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, , Methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenyl Ruureido 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, naphthyl) Sulfinyl group, 2-pyridylsulfinyl group, etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or hetero An arylsulfonyl group (eg, phenylsulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, ethyl Amino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (for example, fluorine atom, chlorine atom, Bromine atom, etc.), fluorinated hydrocarbon groups (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group .

In General Formulas A-1 to A-53, two members out of RA ₁ , RA ₂ , RA ₃ , and RA ₄ may be bonded to each other to form a ring.

In the general formulas A-1 to A-53, as a ring formed by bonding two of RA ₁ , RA ₂ , RA ₃ , RA ₄ , a naphthalene ring, a tetralin ring, an anthracene ring, a phenanthrene ring, a quinoline Examples of the ring structure include a ring, an isoquinoline ring, an indole ring, a benzofuran ring, a benzothiophene ring, an indazole ring, a benzimidazole, a benzothiazole, a benzoxazole, a carbazole, a dibenzofuran, a dibenzothiophene, and a benzotriazole.

    In the general formulas B-1 to B-13, * indicates a location where a bond is formed with the transition metal element M.

In the above general formulas B-1 to B-13, RB ₁ , RB ₂ , and RB ₃ each represent a hydrogen atom or a substituent, and examples of the substituent include RA ₁ in general formulas A-1 to A-53. it can be the same as those of the substituent represented by to RA _4.

In General Formulas B-1 to B-13, _{two of} RB ₁ , RB ₂ , and RB ₃ may be bonded to each other to form a ring.

In the general formulas B-1 to B-13, the ring formed by bonding two of RB ₁ , RB ₂ , and RB ₃ is represented by RA ₁ , RA _{2 in the} general formulas A-1 to A-53. , RA ₃ , the same ring as that formed by combining two of them.

  What is preferable in the complex of the present invention is one in which the ring represented by Bm, Bn or in the general formula (1) is a pyrazole ring or an imidazole ring.

  Further, in the general formula (1), a ligand formed by combining ring An and ring Bn or a ligand formed by combining ring Am and ring Bm is formed. What a ligand is represented by either the following general formula (2), general formula (3), general formula (5), or general formula (6) is preferable.

In the general formula (2) and the general formula _(3), R _{5a1, R 5a2} each independently represent a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aromatic It represents a hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. p represents an integer of 0 to 4.

R _5b1 and R _5b2 represent an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. . X _5a and X _5b each independently represent ═C (R _5e ) — or _═N— . R _5e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.

Ar ₅₁ and Ar ₅₂ each independently represent an aromatic hydrocarbon ring group represented by the general formula (4).

R ₈₁ to R ₈₅ each independently represent a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aryl group, a heteroaryl group, a non-aromatic It represents a hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. Two adjacent groups of R _{81 to} R ₈₅ may be bonded to each other to form a ring. However, R81 = R85 and R82 = R84 are not satisfied.

  * In General formula (2) and (3) represents the site | part which forms a bond with a metal atom.

In the general formula (5) and general formula _{(6), R 6a1} and _{R 6a2} each independently, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, It represents an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. q represents an integer of 0 to 4.

R _6b1 , R _6c1 , R _6b2 , R _6c2 and R _6d2 each independently represent a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. X _6a and X _6b each independently represent ═C (R _6e ) — or _═N— . R _6e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.

* In General formula (5) and General formula (6) represents the site | part which forms a bond with an Ir atom. Ar ₆₁ and Ar ₆₂ are synonymous with Ar ₅₁ and Ar ₅₂ in General Formula (2) and General Formula (3), and represent an aromatic hydrocarbon group represented by General Formula (4). * In General formula (5) and General formula (6) represents the site | part which forms a bond with a metal atom.

  Next, although the specific example of the complex used for this invention is given, this invention is not limited to these.

<< Configuration of organic EL element >>
The organic EL element of the present invention is preferably an organic EL element in which one or a plurality of organic layers are provided between a pair of electrodes and the pair of electrodes. For example, the organic EL element may have the layer structure (i) or (ii). In the present invention, the organic layer means a layer containing an organic compound.
(I) Anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode (ii) anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / Electron transport layer / electron injection layer / cathode << 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 or the electron transport layer and 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 light emitting layer preferably contains an isomer mixed metal complex composition as a phosphorescent light emitting material for organic EL. The light emitting layer preferably contains a host compound.

  The total thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the stability of the emission color against the driving current and the uniformity of the film, preventing unnecessary application of high voltage during light emission. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 to 200 nm, and particularly preferably in the range of 10 to 100 nm.

(Combination with conventionally known dopants)
In addition, the light emitting dopant according to the present invention may be used in combination of a plurality of types of compounds, and combinations of phosphorescent dopants having different structures or phosphorescent dopants and fluorescent dopants within a range that does not impair the effects of the present invention. You may use it in combination.

  Here, specific examples of conventionally known light-emitting dopants that may be used in combination with the iridium complex compound represented by the general formula (1) according to the present invention are given as light-emitting dopants (also referred to as dopant compounds). The present invention is not limited to these.

(2) Host compound In the present invention, the host compound (also referred to as a light-emitting host) is a compound contained in the light-emitting layer and has a mass ratio of 20% or more in that layer and room temperature (25 ° C). Is defined as a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.1. 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.

  There is no restriction | limiting in particular as a host compound which can be used for this invention, The compound conventionally used with an organic EL element can be used. 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 the known host compound 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, conventionally known host compounds may be used alone or in combination of two or more. 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. Moreover, it becomes possible to mix different light emission by using multiple types of the metal complex of this invention used as said phosphorescence dopant, and / or a conventionally well-known compound, and, thereby, arbitrary luminescent colors can be obtained.

  The host compound used in the present invention may be a low molecular compound, a high molecular compound having a repeating unit, or a low molecular compound (polymerizable host compound) having a polymerizable group such as a vinyl group or an epoxy group. Of course, one or more of such compounds may be used.

  Specific examples of known host compounds 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.

  The complex of the present invention can further suppress the cohesiveness of the complex itself by appropriately interacting the host compound and the complex. The host compound used in this case is preferably one that can actively interact with the complex, and a structure in which aggregation between the host compounds is suppressed is appropriate. Specifically, those having a partial structure capable of interacting with the aryl group of the complex molecule through the π plane and a partial structure that suppresses interaction with other host compounds are preferable.

Although it cannot be specified as a chemical structure, the structural characteristics of preferred host compounds are listed;
a. A biaryl structure capable of free rotation; b. A host compound having a biaryl structure capable of free rotation has a dibenzofuran structure; c. A host compound having a biaryl structure capable of free rotation has a carbazole structure; d. A host compound having a biaryl structure that can freely rotate has an unsubstituted phenyl group.

  Specific examples of preferred host compounds that can be used with the complex of the present invention are given below, but the present invention is not limited thereto.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided with a single layer or 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 polycyclic aromatic hydrocarbons such as nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, naphthalene perylene, Ring tetracarboxylic anhydride, carbodiimide, fluorenylidenemethane derivative, anthraquinodimethane and anthrone derivative, oxadiazole derivative, carboline derivative, or at least carbon atoms of the hydrocarbon ring constituting the carboline ring of the carboline derivative Derivatives having a ring structure, one of which is substituted with a nitrogen atom, hexaazatriphenylene derivatives and the like.

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

  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. The film is preferably formed by thinning by a coating method, a curtain coating method, an LB method (such as Langmuir Brodgett method)).

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

  Further, an n-type dopant such as a metal compound such as a metal complex or a metal halide may be doped.

  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 organic EL element of this invention is given, this invention is not limited to these.

  These electron transport materials can also be used as a host compound for the light emitting layer.

"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, 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. You may let them. 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) ) ”, Chapter 2,“ Electrode Materials ”(pages 123 to 166), which has 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 typified by vanadium oxide, amorphous carbon buffer layer, polyaniline as described in JP-T-2003-519432 and JP-A-2006-135145 Examples thereof include a polymer buffer layer using a conductive polymer such as (emeraldine) or polythiophene, an ortho-metalated complex layer represented by tris (2-phenylpyridine) iridium complex, and the like.

  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 having a function of transporting electrons and a very small ability to transport holes. By blocking the holes, the probability of recombination of electrons and holes can be improved.

  Moreover, the structure of the electron carrying layer mentioned above can be used as a hole-blocking layer concerning this invention as needed.

  The hole blocking layer of the organic EL device of the present invention is preferably provided adjacent to the light emitting layer.

  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 mentioned 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 an electron at the HOMO (highest occupied molecular orbital) level of the compound to the vacuum level, and can be obtained, for example, by 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 value (eV unit converted value) calculated by performing structure optimization using B3LYP / 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 low energy electron spectrometer “Model AC-3” manufactured by Riken Keiki Co., Ltd. or a method known as ultraviolet photoelectron spectroscopy can be suitably used.

  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 having a function of transporting holes while having a remarkably small ability to transport electrons. The probability of recombination of electrons and holes can be improved by blocking.

  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 transporting layer according to the present invention is preferably 3 to 100 nm, and more preferably 5 to 30 nm.

《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. 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.

  Further, azatriphenylene derivatives such as those described in JP-T-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.

  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-diphenylaminostilbene; N-phenylcarbazole and also two condensations described in US Pat. No. 5,061,569 Having an aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308688 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (MTDATA) in which three triphenylamine units described in the publication are linked in a starburst type Etc.

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

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  JP-A-11-251067, J. Org. Huang et. al. A so-called p-type hole transport material 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, about 5 nm-5 micrometers, Preferably it exists in the range of 5-200 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. Pat. 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.

"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 (TAC), cellulose acetate butyrate, cellulose acetate propionate ( CAP), cellulose esters such as cellulose acetate phthalate, 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. Water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. , Relative humidity (90 ± 2)% RH) is preferably 0.01 g / (m ² · 24 h) or less, and further, oxygen measured by a method according to JIS K 7126-1987. A high barrier film having a permeability of 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 10 ⁻⁵ g / (m ² · 24 h) or less is preferable.

  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, and more preferably 5% or more.

  Here, external extraction quantum efficiency (%) = (number of photons emitted to the outside of the organic EL element / number of electrons flowed 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 a thin film, for example, a 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, or 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 device 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, Aromatic hydrocarbons such as mesitylene and 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.

  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.

Further, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the method 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.

  Further, 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, and the like 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 is processed on the light extraction side of the substrate so as to provide, for example, a microlens array structure, or combined with a so-called condensing sheet, for example, with respect to a specific direction, for example, the device light emitting surface By condensing in the front direction, the luminance in a specific direction can be increased.

  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 μm 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.

When the organic EL element of the present invention is a white element, white means that the chromaticity in the CIE1931 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, but preferably the vapor deposition method, the ink jet method, the spin coating method, and the printing method.

  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.

  When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed when a voltage of about 2 V to 40 V is applied 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. 2 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, and the pixels for each scanning line respond to the image data signal by the scanning signal. The image information is sequentially emitted to scan the image and display the image information on the display unit A.

  FIG. 3 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.

  FIG. 3 shows a case where 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. 4 is a circuit diagram of the 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. 4, 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 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. The power supply line 7 connects the organic EL element 10 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, since the capacitor 13 holds the charged potential of the image data signal even when the driving of the switching transistor 11 is turned off, the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

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

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or 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. 5 is a schematic diagram of a passive matrix display device. In FIG. 5, 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 red, green and blue, or two using the complementary colors such as blue and yellow, blue green and orange. 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 to be in close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, and as shown in FIG. 6 and FIG. Can be formed.

  FIG. 6 shows a schematic diagram of the lighting device, and the organic EL element 101 of the present invention is covered with a glass cover 102 (in the sealing operation with the glass cover, the organic EL element 101 is brought 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. 7 is a cross-sectional view of the lighting device. In FIG. 7, reference numeral 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.

<< Preparation of Exemplified Compound 71 >>
(Synthesis of Intermediate 2)
The intermediate 1 of 3.53 g of iridium chloride and 6.56 g was heated and refluxed in a mixed solvent of 65 ml of 1-propanol and 13 ml of water under a nitrogen atmosphere for 3 hours. The reaction solution was cooled to room temperature, and the precipitated crystals were collected by filtration, washed with methanol, and dried to obtain 6.44 g (yield 90%) of Intermediate 2.

(Synthesis of Exemplified Compound 71)

  1.43 g of Intermediate 1 and 0.6 g of silver trifluoroacetate and 0.9 g of Intermediate 3 were stirred for 5 hours while heating at 140 ° C. in 14 ml of phenyl acetate. After cooling the reaction solution to room temperature, insoluble matters were filtered off, and the filtrate was purified by silica gel column chromatography to obtain 1.09 g of Exemplified Compound 71 (yield 50%).

  The exemplary compound 71 obtained by the above operation was analyzed by high performance liquid chromatography using a column (ODS) packed with silica gel whose surface was modified with an octadecyl group as a stationary phase, and it was found to be a mixture of two kinds of components. .

  FIG. 8 is a measurement chart of high performance liquid chromatography. FIG. 8 shows a measurement chart of high performance liquid chromatography of the exemplified compound 71. Peaks corresponding to the diastereomeric component of Exemplified Compound 71 are observed at retention times of 13.2 minutes (area ratio of 57.3%) and 13.7 minutes (area ratio of 42.4%).

  Since ODS is an achiral column, the separated components are not enantiomers but diastereomers. That is, the optical isomerism of the Δ-coordinate and Λ-isomer of the 6-coordinate octahedral Ir complex, and the optical isomerism caused by the formation of the atropisomer by the complexing of the bond axis between the 3,4-dimethylphenyl group and the imidazole ring. Among the four isomeric complexes of enantiomers and diastereomers consisting of the two chiral centers of diastereomer, that is, 0Λ-1R and 0Δ-1R are separated, and eventually 0Λ-1R, 0Δ It can be considered that it is separated as a mixture of −1S and a mixture of 0Δ-1R and 0Λ-1S. Furthermore, each component was separated by preparative HPLC to give 0.35 g and 0.29 g of Exemplified Compounds 71-A and 71-B, which are enantiomer mixture components of Diastereomer Resolution of Exemplified Compound 71, respectively. It was. Although each steric configuration could not be confirmed, it was confirmed from the nuclear magnetic resonance spectrum and the mass spectrum that it is appropriate as the exemplified compound 71.

[Example 1] (Vapor deposition system)
<< Production of Organic EL Element 1-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 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, this ITO transparent electrode The provided transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under a condition of 30 seconds, and then 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 deposition apparatus, while α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl) is attached to a resistance heating boat made of molybdenum. 200 mg, 200 mg of CBP (4,4′-N, N′-dicarbazole biphenyl) is put into another molybdenum resistance heating boat, 200 mg of the exemplified compound 71 is put into another molybdenum resistance heating boat, 200 mg of BCP (2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline) was placed in a resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.
Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was heated by energization, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. The hole transport layer was provided.

  Further, the heating boat containing CBP and the heating boat containing the comparative compound 1 are energized and heated, and are co-deposited on the hole transport layer at a deposition rate of 0.1 nm / second and 0.010 nm / second, respectively. A 40 nm light emitting layer was provided.

  Furthermore, the heating boat containing BCP was energized and heated, and was deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to provide an electron transport layer of 30 nm.

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

<< Production of Organic EL Elements 1-2 to 1-3 >>
In the production of the organic EL device 1-1, the organic compound was similarly obtained except that it was changed to the exemplified compounds 71-A and 71-B which are diastereomeric components of the exemplified compound 71 isolated in the synthesis example instead of the exemplified compound 71. EL elements 1-2 to 1-3 were produced.

<< Evaluation of Organic EL Elements 1-1 to 1-3 >>
When evaluating the obtained organic EL element, the non-light-emitting surface of each organic EL element after production is covered with a glass cover, and the glass cover side periphery where the glass cover and the glass substrate on which the organic EL element is produced contacts An epoxy photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) was applied as a sealant to the cathode side, and this was adhered to the transparent support substrate to remove the organic EL element from the glass substrate side. The part was irradiated with UV light, cured, and sealed to form an illumination device as shown in FIGS.

  The following evaluation was performed for each sample thus prepared. The evaluation results are shown in Table 1.

(1) External extraction quantum efficiency (also simply referred to as efficiency)
The organic EL element is turned on at room temperature (about 23 to 25 ° C.) under a constant current condition of 2.5 mA / cm 2, and the emission luminance (L) [cd / m 2] immediately after the start of lighting is measured to take out from the outside. The quantum efficiency (η) was calculated.

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

(2) Change rate of resistance value before and after driving organic EL element “Thin Film Evaluation Handbook” Technosystem, Inc., page 423 to page 425, with reference to the measurement method described in Solartron 1260 type impedance analyzer and 1296 type dielectric Using the interface, the resistance value at a bias voltage of 1 V of the light emitting layer of the produced organic EL element was measured.

The resistance value of the light emitting layer before and after driving was measured after driving the organic EL element at room temperature (about 23 ° C. to 25 ° C.) under constant current conditions of ^2.5 mA / cm ² for 1000 hours. The change rate of the resistance value was calculated by the calculation formula shown. Table 1 shows the relative ratio when the rate of change in resistance value of the organic EL element 1-1 is 100.

Change rate of resistance value before and after driving = | (resistance value after driving / resistance value before driving) −1 | × 100
A value closer to 0 indicates a smaller rate of change before and after driving.

  As shown in Table 1, the complex of the present invention is a mixture of diastereomeric components having four isomers even in the diastereomeric-divided Exemplified Compounds 71-A and 71-B having two isomers. Since there is no change in efficiency even in the exemplified compound 71, it can be seen that the light emission performance between the diastereomers of the complex of the present invention is equivalent and the film properties are equivalent.

  On the other hand, since the devices 1-2 and 1-3 produced using a single diastereomer component have a larger variation in the resistance value of the film than the device 1-1 produced using a mixture of diastereomeric components, It was confirmed that the stability of the film state was improved by the mixture of diastereomeric components.

  Similar isolation procedures were performed for other exemplary compounds, and each diastereomer component was isolated and confirmed to be the target compound. An isolated diastereomer and a mixture of diastereomers were prepared in the same manner as in Device 1-1 to Device 1-3 in Example 1, and the performance of the device was evaluated. Equivalent evaluation results were obtained with a mixture of stereomers.

[Example 2] (Vapor deposition system)
<< Preparation of Organic EL Element 2-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 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, this ITO transparent electrode The provided transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under a condition of 30 seconds, and then 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 deposition apparatus, while 200 mg of α-NPD is put in a molybdenum resistance heating boat, and 200 mg of OC-30 is put in another resistance heating boat made of molybdenum. 200 mg of dopant compound D-26 was put in a resistance heating boat, and 200 mg of BCP was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.
Next, after reducing the pressure of the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was heated by energization, and deposited on the hole injection layer at a deposition rate of 0.1 nm / sec. The hole transport layer was provided.

  Furthermore, the heating boat containing OC-30 and the heating boat containing dopant compound D-26 as a comparative compound were energized and heated, and the positive rate was 0.1 nm / second and 0.010 nm / second, respectively. A 40 nm light-emitting layer was provided by co-evaporation on the hole transport layer.

  Furthermore, the heating boat containing BCP was energized and heated, and was deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to provide an electron transport layer of 30 nm.

  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 2-75 >>
Organic EL elements 2-2 to 2-75 were similarly manufactured except that D-26 or OC-30 was changed to the compounds shown in Table 1 in the preparation of the organic EL element 1-1.

  The structure of the comparative compound is shown below.

<< Evaluation of Organic EL Elements 2-1 to 2-75 >>
When evaluating the obtained organic EL element, the non-light-emitting surface of each organic EL element after production is covered with a glass cover, and the glass cover side periphery where the glass cover and the glass substrate on which the organic EL element is produced contacts An epoxy photo-curing adhesive (Luxtrac LC0629B manufactured by Toagosei Co., Ltd.) was applied as a sealant to the cathode side, and this was adhered to the transparent support substrate to remove the organic EL element from the glass substrate side. The portion is irradiated with UV light, cured, sealed, and an illumination device as shown in FIG. 6 and FIG. 7 is formed to measure the resistance value of the light emitting layer and the organic EL element using an impedance spectrometer. The change rate of the half width of the emission spectrum of was measured.

(1) Change rate of resistance value before and after organic EL element driving “Thin Film Evaluation Handbook” Technosystem, Inc., page 423 to page 425, with reference to the measurement method described in Solartron 1260 type impedance analyzer and 1296 type dielectric Using the interface, the resistance value at a bias voltage of 1 V of the light emitting layer of the produced organic EL element was measured.

The resistance value of the light emitting layer before and after driving was measured after driving the organic EL element at room temperature (about 23 ° C. to 25 ° C.) under constant current conditions of ^2.5 mA / cm ² for 1000 hours. The change rate of the resistance value was calculated by the calculation formula shown. Table 1 shows the relative ratio when the rate of change of the resistance value of the organic EL element 2-1 is 100.

Change rate of resistance value before and after driving = | (resistance value after driving / resistance value before driving) −1 | × 100
A value closer to 0 indicates a smaller rate of change before and after driving.

(2) Rate of change of half width of emission spectrum before and after driving organic EL element Driving after driving organic EL element for 1000 hours under constant current conditions of room temperature (about 23 ° C. to 25 ° C.) and ^2.5 mA / cm ² The emission spectra before and after were measured using CS-1000 (manufactured by Konica Minolta Optics Co., Ltd.), and the rate of change in the half width of the peak wavelength was calculated by the calculation formula shown below. Tables 2 to 4 show relative ratios when the rate of change of the half width of the organic EL element 2-1 is 100.

Rate of change of half width before and after driving = | (half width after driving / half width before driving) −1 | × 100
A value closer to 0 indicates a smaller change rate before and after driving.

From Tables 2 to 4, it can be seen that the resistance value change rate and the emission spectrum half-value width change rate are substantially correlated. That is, it can be said that the low-efficiency change of the light emitting layer over time is a basic physical property value for evaluating the durability of the organic EL element. Next, data comparison between each element in Tables 2 to 4 The organic EL elements 2-10 to 1-75 of the present invention were compared with the organic EL elements 2-1 to 2-9 of the comparative examples. Since it was shown that the change rate of the resistance value and the half-value width of the emission spectrum was small, an organic EL device having a small change in physical properties of the thin film of the light emitting layer could be obtained.
In addition, in the host compound coexisting with the complex of the present invention, it can be seen that the film properties are further stabilized by making it a more preferable embodiment. In addition, in all the exemplary compounds of the present invention, the abundance ratio of the number of isomers is actually set. Although it could not be measured, the tendency that the resistance value change rate and the emission spectrum half-value width change rate decrease as the number of theoretical isomers shown in Tables 2 to 4 increases is clearly recognized. This is a result supporting the suppression of physical property change of the light emitting layer thin film due to the entropy increasing effect which forms the basis of the technical idea of the present invention. It was confirmed that this is a universal stabilization technique regardless of the ligand skeleton of the complex.

[Example 3] (Coating system)
<< Production of Organic EL Element 3-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 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, this ITO transparent electrode The provided transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  On this transparent support substrate, using a solution obtained by diluting poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, Bayer, Baytron P Al 4083) to 70% with pure water, 3000 rpm, A thin film was formed by spin coating under a condition of 30 seconds, and then dried at 200 ° C. for 1 hour to provide a first hole transport layer having a thickness of 20 nm.

  The substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of ADS254BE (American Dye Source, Inc.) dissolved in 10 ml of monochlorobenzene was used on the first hole transport layer at 2500 rpm for 30 seconds. A thin film was formed by spin coating. Furthermore, it vacuum-dried at 130 degreeC for 1 hour, and the 2nd positive hole transport layer was formed.

  A thin film was formed on this second hole transport layer by spin coating using a solution of 100 mg of OC-30 and 13 mg of dopant compound D-26 dissolved in 10 ml of butyl acetate at 1000 rpm for 30 seconds. Formed. Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the light emitting layer with a film thickness of about 45 nm.

  Next, a thin film was formed on this light emitting layer by spin coating under a condition of 1000 rpm and 30 seconds using a solution of 50 mg of BCP dissolved in 10 ml of hexafluoroisopropanol (HFIP). Furthermore, it vacuum-dried at 60 degreeC for 1 hour, and was set as the electron carrying layer with a film thickness of about 25 nm.

Subsequently, this substrate is fixed to a substrate holder of a vacuum deposition apparatus, and after the vacuum chamber is depressurized to 4 × 10 ⁻⁴ Pa, 0.4 nm of potassium fluoride is deposited as a cathode buffer layer, and further, 110 nm of aluminum is deposited. Thus, a cathode was formed, and an organic EL element 3-1 was produced.

<< Production of Organic EL Elements 3-2 to 3-80 >>
In the production of the organic EL element 3-1, organic EL elements 3-2 to 3-80 were similarly produced except that D-26 or OC-30 was changed to the compounds shown in Tables 5 to 7.

<< Evaluation of Organic EL Elements 3-1 to 3-80 >>
When evaluating the obtained organic EL element, it was sealed in the same manner as the organic EL element 2-1 of Example 2, and an illumination device as shown in FIGS. 6 and 7 was formed and evaluated.

  Each sample thus produced was evaluated for the rate of change in the resistance value of the light emitting layer in the same manner as in Example 1. The evaluation results are shown in Tables 5-7.

  From Tables 5 to 7, the organic EL elements 3-10 to 3-80 of the present invention have a light emitting layer resistance value and a half-value width of the emission spectrum with respect to the organic EL elements 3-1 to 3-9 of the comparative example. It was shown that the rate of change of the organic EL element was small, so that an organic EL device having a small change in physical properties of the thin film of the light emitting layer could be obtained.

  Moreover, it turns out that film | membrane physical property is stabilized more by setting it as a more preferable aspect in the host compound coexisting with the complex of this invention. In addition, in all the exemplary compounds of the present invention, the abundance ratio of the number of isomers could not be actually measured, but the resistance value changes as the theoretical number of isomers present in Tables 5 to 7 increases. The tendency for the rate and the emission spectrum half-width change rate to decrease is clearly recognized. This is a result supporting the suppression of physical property change of the light emitting layer thin film due to the entropy increasing effect which forms the basis of the technical idea of the present invention. It was confirmed that this is a universal stabilization technique regardless of the ligand skeleton of the complex.

[Example 4] (White light emitting system)
<< Preparation of Organic EL Element 4-1 >>
After patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 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, this ITO transparent electrode The provided transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

  This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, and TPD ((4,4′-bis [N- (3-methylphenyl) -N-phenylamino] biphenyl)) is attached to a molybdenum resistance heating boat. 200 mg, 200 mg CBP in another molybdenum resistance heating boat, 200 mg dopant compound D-9 in another molybdenum resistance heating boat, 200 mg dopant compound D-1 in another molybdenum resistance heating boat, 200 mg of dopant compound D-6 was put in another resistance heating boat made of molybdenum, and 200 mg of BCP was put in another resistance heating boat made of molybdenum, and attached to a vacuum deposition apparatus.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing TPD is heated by energization, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / second to form a 10 nm hole transport layer. Was provided.

  Further, the heating boat containing CBP, D-9, D-1, and D-6 was energized and heated, and the deposition rates were 0.1 nm / second, 0.025 nm / second, 0.0007 nm / second, and 0.005 nm, respectively. A 60 nm light emitting layer was provided by co-evaporation on the hole transport layer at 0002 nm / second.

  Further, the heating boat containing BCP was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 20 nm electron transport layer.

  Then, 0.5 nm of potassium 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 4-1 was produced.

When the produced organic EL element 4-1 was energized, almost white light was obtained, and it was found that it could be used as a lighting device. In addition, when the emitted light colors of the organic EL elements 4-2 to 4-9 of the present invention were measured for the front luminance at a viewing angle of 2 degrees, the chromaticity in the CIE 1931 color system at 1000 cd / m ² was x = 0.40. It was confirmed that white light was exhibited in the region of ± 0.07, y = 0.40 ± 0.1.

<< Production of Organic EL Elements 4-2 to 4-9 >>
Organic EL elements 4-2 to 4-9 were similarly manufactured except that D-9 was changed to the compounds shown in Table 8 in the preparation of the organic EL element 3-1.

<< Evaluation of Organic EL Elements 4-1 to 4-9 >>
When the rate of change in the resistance value of the light emitting layer was measured by the same method as in Example 1, it was confirmed that the organic EL device of the present invention had a value less than half that of the comparison.

[Example 5] (Color)
<< Production of Organic EL Element 5-1 >>
(Production of blue light emitting element)
The organic EL device 2-55 of Example 2 was used as a blue light emitting device.

(Production of green light emitting element)
In the organic EL device 2-55 of Example 2, a green light emitting device was produced in the same manner except that the exemplified compound 55 was changed to D-1, and this was used as a green light emitting device.

(Production of red light emitting element)
A red light-emitting element was produced in the same manner as in Example 2 except that the organic compound element 55 in Example 2 was changed to D-6 in the exemplified compound 55, and this was used as a red light-emitting element.

  The red, green, and blue light emitting organic EL elements produced above were juxtaposed on the same substrate, and an active matrix type full color display device having a configuration as shown in FIG. 2 was produced. In FIG. 3, only the schematic diagram of the display part A of the produced display device is shown.

  That is, a plurality of pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) juxtaposed with a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate. 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 (for details, 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. The image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was produced by appropriately juxtaposing red, green, and blue pixels.

  It has been found that when this full-color display device is driven, high brightness, high durability, and clear full-color moving image display 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 31 Support substrate 32 Anode 33 Hole injection layer 34 Hole transport layer 35 Light emitting layer 36 Electron transport layer 37 Electron injection Layer 38 Cathode 39 Sealing adhesive 40 Sealing member 50 Organic functional layer 100, 101 Organic EL element 102 Glass cover 105 Cathode 106 Organic EL layer 107 Glass substrate with transparent electrode 108 Nitrogen gas 109 Water catching agent A Display unit B Control unit

Claims (11)

An organic electroluminescence device comprising a pair of electrodes and one or a plurality of organic layers including a light emitting layer between the pair of electrodes,
The light-emitting layer contains a phosphorescent organic electroluminescence light-emitting material that is an isomer mixed metal complex composition composed of a metal atom and a plurality of ligands, and the plurality of ligands are: A ligand having the same structure or a different ligand,
In the isomer mixed metal complex composition, at least one of the plurality of ligands has an aromatic ring as a substituent, and free rotation of a bond axis between the aromatic ring and the ligand is the metal atom. An organic electroluminescence device comprising a mixture of atropisomers formed by the fact that free rotation cannot be performed due to the influence of other ligands in the complex molecule due to the complex formation between the ligand and the ligand . 2. The organic electroluminescence device according to claim 1, wherein the atropisomer is represented by the following general formula (1).

(In the formula, ring Am, ring An, ring Bm and ring Bn represent a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocycle, and further , an alkyl group, cycloalkyl as a substituent. Group, alkenyl group, alkynyl group, aromatic hydrocarbon ring group, aromatic heterocyclic group, heterocyclic group, alkoxy group, cycloalkoxy group, aryloxy group, alkylthio group, cycloalkylthio group, arylthio group, alkoxycarbonyl group, Aryloxycarbonyl group, sulfamoyl group, acyl group, acyloxy group, amide group, carbamoyl group, ureido group, sulfinyl group, alkylsulfonyl group, arylsulfonyl group or heteroarylsulfonyl group, amino group, halogen atom, fluorohydrocarbon group , cyano group, nitro group, hydroxy group, optionally having a mercapto group good . Ring Am, Bm, _Xm 1 in An and _{Bn, Xm 2, Xm 3,} Xm 4 and _{Xm 5, Xn 1, Xn 2} , Xn 3, Xn 4 and Xn _5, respectively, a carbon atom or a nitrogen atom Represent.
When Xm ₁ and M and Xn ₁ and M each form a coordination bond, Xm ₄ and M and Xn ₄ and M each form a covalent bond,
When Xm ₁ and M and Xn ₁ and M each form a covalent bond, Xm ₄ and M and Xn ₄ and M each form a coordinate bond.
However, Xn1 and Xn4 or Xm1 and Xm4 do not represent a carbon atom at the same time.
Ar ^m and Ar ⁿ represent an aromatic hydrocarbon ring group or an aromatic heterocyclic group in which the bond axis to ring Bm or ring Bn does not have a symmetry axis, and a halogen atom, a cyano group, an alkyl group, It may have an alkenyl group, an alkynyl group, an alkoxy group, an amino group, an arylalkyl group, an aryl group, a heteroaryl group, a non-aromatic hydrocarbon group or a non-aromatic heterocyclic group . M represents iridium or platinum. m and n represent an integer of 0 to 3, and m + n is 2 or 3. ) In the said General formula (1), the ring Bm, the ring Bn, the ring Am, or the ring An represents an imidazole ring or a pyrazole ring, The organic electroluminescent element of Claim 2 characterized by the above-mentioned. In the general formula (1), a ligand formed by combining ring An and ring Bn, or a ligand formed by combining ring Am and ring Bm is represented by the following general formula (2). , general formula (3), the general formula (5) or an organic electroluminescence device according to claim 2 or claim 3, characterized in that represented by any one of formulas (6).

(Wherein, R _5a1 and R _5a2 each independently, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aromatic hydrocarbon ring group, aromatic It represents a heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent, and p represents an integer of 0 to 4.
R _5b1 , R _5b2 and R _{5c1 each} represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and further has a substituent. May be. X _5a and X _5b each independently represent ═C (R _5e ) — or _═N— . R _5e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
Ar ₅₁ and Ar ₅₂ each independently represent an aromatic hydrocarbon ring group represented by the general formula (4).

R ₈₁ ~ ₈₅ are each independently a hydrogen atom, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, an aryl group, a heteroaryl group, non-aromatic hydrocarbons It represents a hydrogen ring group or a non-aromatic heterocyclic group, and may further have a substituent. Two adjacent groups of R _{81 to} R ₈₅ may be bonded to each other to form a ring. However, R ₈₁ = R ₈₅ and R ₈₂ = R ₈₄ are not _satisfied .
* In general formula (2) and (3) represents the site | part which forms a bond with a metal atom.

In the general formula (5) and general formula _{(6), R 6a1} and _{R 6a2} each independently, a halogen atom, a cyano group, an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, an amino group, the aryl alkyl group, It represents an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group, and may further have a substituent. q represents an integer of 0 to 4.
R _6b1 , R _6c1 , R _6b2 , R _6c2 and R _6d2 each independently represent a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic group. It represents a heterocyclic group and may further have a substituent. X _6a and X _6b each independently represent ═C (R _6e ) — or _═N— . R _6e represents an alkyl group, an aromatic hydrocarbon ring group, an aromatic heterocyclic group, a non-aromatic hydrocarbon ring group or a non-aromatic heterocyclic group.
* In General formula (5) and General formula (6) represents the site | part which forms a bond with an iridium atom.
Ar ₆₁ and Ar ₆₂ are synonymous with Ar ₅₁ and Ar ₅₂ in General Formula (2) and General Formula (3), and represent an aromatic hydrocarbon group represented by General Formula (4).
* In General formula (5) and General formula (6) represents the site | part which forms a bond with a metal atom. ) The organic electroluminescence device according to any one of claims 2 to 4 , wherein M represents an iridium atom. The light-emitting layer is, in any one of claims 1, characterized by containing a mixture of a host compound having a biaryl structure freely rotate and the organic electroluminescence light emitting material to claim 5 The organic electroluminescent element of description. The organic electroluminescence device according to claim 6 , wherein the host compound having a biaryl structure capable of freely rotating is a compound having a dibenzofuran structure. The organic electroluminescence device according to claim 6 , wherein the host compound having a biaryl structure capable of freely rotating is a compound having a carbazole structure. The organic electroluminescence device according to claim 6 , wherein the host compound having a biaryl structure capable of freely rotating is a compound having an unsubstituted phenyl group. An illuminating device comprising the organic electroluminescence element according to any one of claims 1 to 9 . A display device comprising the organic electroluminescence element according to any one of claims 1 to 9 .

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