JP5510335B2 - ORGANIC ELECTROLUMINESCENT ELEMENT, ORGANIC ELECTROLUMINESCENT ELEMENT MATERIAL, DISPLAY DEVICE AND LIGHTING DEVICE - Google Patents

Description

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

  Conventionally, as a light-emitting electronic display device, there is an electroluminescence display (hereinafter referred to as ELD). Examples of the constituent elements of ELD include inorganic electroluminescent elements and organic electroluminescent elements (hereinafter also referred to as organic EL elements).

  Inorganic electroluminescent elements have been used as planar light sources, but an alternating high voltage is required to drive the light emitting elements.

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

  However, in organic EL elements for practical use in the future, development of organic EL elements that emit light efficiently and with high luminance with lower power consumption is desired.

  In Japanese Patent No. 3093796, a small amount of a phosphor is doped into a stilbene derivative, a distyrylarylene derivative or a tristyrylarylene derivative to achieve an improvement in light emission luminance and a longer device lifetime.

  Further, an element having an organic light-emitting layer in which an 8-hydroxyquinoline aluminum complex is used as a host compound and a small amount of phosphor is doped thereto (for example, JP-A 63-264692), and an 8-hydroxyquinoline aluminum complex is used as a host compound. For example, an element having an organic light emitting layer doped with a quinacridone dye (for example, JP-A-3-255190) is known.

  As described above, when light emission from excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, and thus the generation probability of luminescent excited species is 25%. Since the efficiency is about 20%, the limit of the external extraction quantum efficiency (ηext) is set to 5%.

  However, since Princeton University reported on an organic EL device using phosphorescence emission from an excited triplet (MA Baldo et al., Nature, 395, 151-154 (1998)), Research on materials that exhibit phosphorescence has become active.

  For example, M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), US Pat. No. 6,097,147, and the like.

  When the excited triplet is used, the upper limit of the internal quantum efficiency is 100%. In principle, the luminous efficiency is four times that of the excited singlet, and there is a possibility that almost the same performance as a cold cathode tube can be obtained. Therefore, it is attracting attention as a lighting application.

  For example, S.M. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001), etc., many compounds are being studied for synthesis centering on heavy metal complexes such as iridium complexes.

  In addition, the aforementioned M.I. A. Baldo et al. , Nature, 403, 17, 750-753 (2000), studies have been made using tris (2-phenylpyridine) iridium as a dopant.

In addition, M.M. E. Thompson et al. In The 10th International Works on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) used L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac), e 0 g, Tetsuo Tsutsui, etc., again The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), the dopant as tris (2-(p-tolyl) pyridine) iridium (Ir _{(ptpy) 3),} tris ( Studies using benzo [h] quinoline) iridium (Ir (bzq) ₃ ) and the like are being conducted (note that these metal complexes are generally called ortho-metalated iridium complexes).

  In addition, the S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) and Japanese Patent Application Laid-Open No. 2001-247859, etc., attempts have been made to form devices using various iridium complexes.

  In order to obtain high luminous efficiency, in the 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu), Ikai et al. Uses a hole transporting compound as a host of a phosphorescent compound.

  In addition, M.M. E. Thompson et al. Use various electron transporting materials as a host of phosphorescent compounds, doped with a novel iridium complex.

  Orthometalated complexes in which the central metal is platinum instead of iridium are also attracting attention. With respect to this type of complex, many examples are known in which ligands are characterized.

  In either case, the light emission brightness and light emission efficiency of the light emitting device are greatly improved compared to conventional devices because the emitted light is derived from phosphorescence. There was a problem that it was lower than the conventional element.

  As described above, it is difficult for phosphorescent highly efficient light-emitting materials to shorten the light emission wavelength and improve the light emission lifetime of the device, and the performance that can withstand practical use cannot be sufficiently achieved.

  In addition, regarding wavelength shortening, introduction of an electron withdrawing group such as a fluorine atom, a trifluoromethyl group, a cyano group or the like into phenylpyridine as a substituent, and picolinic acid or a pyrazabole-based ligand as a ligand. It is known to introduce.

  However, with these ligands, the emission wavelength of the light-emitting material is shortened to achieve blue, and a high-efficiency device can be achieved. On the other hand, the light-emitting lifetime of the device is greatly deteriorated, so an improvement in the trade-off is required. It was.

  It is disclosed that a metal complex having phenylpyrazole as a ligand is a light-emitting material having a short emission wavelength (see, for example, Patent Documents 1 and 2).

  Furthermore, a metal complex formed from a ligand having a partial structure in which a 6-membered ring is condensed to a 5-membered ring of phenylpyrazole is disclosed (for example, see Patent Documents 3 and 4).

  In recent years, imidazophenanthridines have been disclosed as materials that newly emit blue light (see, for example, Patent Documents 5 and 6 and Non-Patent Document 1).

  These compounds have a phosphorescence maximum peak in the vicinity of 465 nm and can be expected as a blue dopant for organic EL. However, the light emission lifetime and light emission efficiency of the device are not yet satisfactory.

International Publication No. 2004/085450 Pamphlet JP 2005-53912 A JP 2006-28101 A US Pat. No. 7,147,937 US Patent Application Publication No. 2007/190359 US Patent Application Publication No. 2008/297033

Journal of Applied Physics 103, 044509 (2008)

  An object of the present invention is to provide an organic EL element that exhibits high light emission efficiency, has a long light emission lifetime, suppresses initial deterioration, and does not generate dark spots, and a display device and an illumination device including the organic EL element Is to provide.

  At the same time, it is to provide an organic EL element material that exhibits high luminous efficiency with a short wavelength light emission of blue to blue green and has a long emission lifetime.

  The above object of the present invention has been achieved by the following constitution.

1. In an organic electroluminescence device containing at least one light emitting layer sandwiched between an anode and a cathode,
The light emitting layer has an organic layer containing at least one compound containing a partial structure represented by the following general formula (1).

[In formula, E1b-E1o and E1q represent a carbon atom, a nitrogen atom, an oxygen atom, or a sulfur atom respectively, and the frame | skeleton comprised by E1a-E1q has a total of 18 (pi) electrons. E1a and E1p are different from each other and represent a carbon atom or a nitrogen atom. R1a to R1b and R1g to R1i each represent a hydrogen atom or a substituent, R1c, R1e, and R1f are hydrogen atoms, and R1d represents an electron-donating isopropyl group or cyclohexyl group . M represents a group 8-10 transition metal element in the periodic table. ]

2 . 2. The organic electroluminescence device according to 1 above, wherein the partial structure represented by the general formula (1) represents a partial structure represented by the following general formula (4) or (5).

[Wherein, R1a, R1b, R1g, R1h, R1i each represents a hydrogen atom or a substituent, and R1d represents an isopropyl group or a cyclohexyl group . M represents a group 8-10 transition metal element in the periodic table. ]
3 . Said R1b is represented by following General formula (6), The said organic electroluminescent element of 1 or 2 characterized by the above-mentioned.

[Wherein, Z represents an atomic group necessary for forming a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocyclic ring, and A represents a nitrogen atom or a carbon atom. Ra represents a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 4. * Indicates a binding position. ]
4 . 4. The organic electroluminescence device as described in 3 above, wherein the group represented by the general formula (6) is a group represented by the following general formula (7).

[In the formula, Ra represents a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 4. * Indicates a binding position. ]
5 . 5. The organic electroluminescence device as described in 4 above, wherein the group represented by the general formula (7) is a group represented by the following general formula (8).

[In the formula, Ra and Rc each represent a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 3. * Indicates a binding position. ]
6 . Said M represents platinum or iridium, The organic electroluminescent element of any one of said 1-5 characterized by the above-mentioned.

7 . The organic electroluminescence device according to any one of 1 to 6 , wherein the organic layer is formed using a wet process.

8 . It contains at least one kind of compound containing the partial structure represented by the general formula (1) described in 1 or the partial structure represented by the general formula (4) or (5) described in 2 above. An organic electroluminescent element material characterized by the above.

9 . 9. The organic electroluminescence element material according to 8 , wherein M represents platinum or iridium.

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

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

  According to the present invention, there is provided an organic EL element that exhibits high luminous efficiency, has a long emission lifetime, suppresses initial deterioration, and does not generate dark spots, and provides a display device and an illumination device including the organic EL element. In addition, an organic EL element material that exhibits high light emission efficiency and has a long light emission lifetime with blue to blue-green short-wave light emission can be provided.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

Lighting In the organic electroluminescent device of the present invention, the structure as defined in any one of claims 1 to 9 exhibited high luminous efficiency and a long organic electroluminescent device emission lifetime, with the element A device and a display device could be provided.

  Moreover, the organic EL element material useful for the element could be molecularly designed.

  Hereinafter, details of each component according to the present invention will be sequentially described.

《Metal complex (also called metal complex compound)》
The metal complex (also referred to as a metal complex compound) according to the present invention will be described.

  The present inventors paid attention to the organic EL element material used for the light emitting layer of the organic EL element, and examined various metal complex compounds used as a light emitting dopant.

  Among them, in the ligands of conventionally known metal complex compounds, the light emitting material obtained by introducing an electron-withdrawing substituent into the basic skeleton of the metal complex tends to greatly deteriorate the light emission lifetime of the device. However, on the other hand, it has been found that the emission wavelength of the light emitting material is shortened to achieve blue, and an effect of achieving a highly efficient device can be obtained.

  Therefore, the present inventors are expected to achieve the same effect as the introduction of substituents, rather than a conventionally known approach of introducing a substituent into the basic skeleton of the metal complex to control the wavelength and improve the lifetime. We focused on the fused ring that can be formed.

  As a result, the improvement tendency of lifetime was found in several structures. However, when a fused ring as known so far is introduced, the red shift of the emission wavelength is remarkable, resulting in green and red emission.

  The present inventors further proceeded with investigations, and in the general formula (1) according to the present invention, or a compound (metal complex) containing a partial structure represented by any one of the general formula (4) or the general formula (5). When a condensed ring as shown is introduced, the emission wavelength shift of the light emitting material is small, and a light emitting dopant having a long lifetime at a desired emission wavelength has been successfully developed.

  Further, by substituting the phenanthridine skeleton represented by the compound containing the partial structure represented by the general formula (1), or the general formula (4) or the general formula (5) according to the present invention, By combining the size of the atoms and the electronic effect, we have found an effect that enables both short wave and long life.

  For example, according to the above-mentioned Patent Document 1, it is reported that a defect occurs due to the interaction between a host radical and an exciton of a light-emitting dopant as a result of analysis in a device using a compound having a phenanthridine skeleton.

  It has been reported that the defect formation rate is proportional to the phosphorescence lifetime of the luminescent dopant, and shortening the phosphorescence lifetime of the luminescent dopant is one of the keys to extending the lifetime.

  The inventors of the present invention can significantly shorten the phosphorescence lifetime of the luminescent dopant by introducing a substituent at a specific position in the above-described research, and the effect of extending the lifetime accordingly. And the present invention has been completed.

  Moreover, even if it is a ligand which concerns on the partial structure represented by either General formula (1) which concerns on this invention, or General formula (4) or General formula (5), the auxiliary ligand to combine, By introducing a substituent having a long wave as a substituent, the emission wavelength of the metal complex can be controlled in a desired region.

  Therefore, the molecular design for imparting the function of controlling the emission wavelength of the metal complex to a long wave region (green to red) is represented by the general formula (1), the general formula (4) or the general formula ( This is possible by using the partial structure represented by any of 5) as a starting point for the basic skeleton design of a metal complex.

  The compound (metal complex) containing a partial structure represented by the general formula (1), or the general formula (4) or the general formula (5) according to the present invention is a transition metal element each represented by M. Depending on the valence, it can have a plurality of ligands, but all of the ligands may be the same or may have ligands having different structures.

  However, from the viewpoint of preferably obtaining the effects described in the present invention, the type of ligand in the complex is preferably composed of 1 to 2 types, and more preferably 1 type.

  The metal complex according to the present invention includes a moiety (ligand) obtained by removing the transition metal element M from the partial structure represented by the general formula (1), or the general formula (4), or the general formula (5). ) Is most preferably used.

  Here, the term “ligand” refers to a portion obtained by removing the transition metal element M from the partial structure represented by the general formula (1), or the general formula (4) or the general formula (5). It is a rank. Further, conventionally known ligands that can be used for forming the metal complex according to the present invention will be described in detail later.

  Among the compounds having a partial structure represented by the general formula (1) (metal complex), preferably a compound having a partial structure represented by the general formula (4) or (5) (metal complex). is there.

  Hereinafter, the partial structure which the metal complex which concerns on this invention has is demonstrated in detail.

(Partial structure represented by general formula (1))
The partial structure represented by the general formula (1) according to the present invention will be described.

  First, a skeleton composed of E1a to E1q having a total of 18π electrons will be described.

  In the partial structure represented by the general formula (1), the ring formed by E1a to E1e represents a 5-membered aromatic heterocycle, such as an oxazole ring, a thiazole ring, an oxadiazole ring, an oxatriazole ring, Examples include isoxazole ring, tetrazole ring, thiadiazole ring, thiatriazole ring, isothiazole ring, thiophene ring, furan ring, pyrrole ring, imidazole ring, pyrazole ring, and triazole ring.

  Among these, a pyrazole ring, an imidazole ring, an oxazole ring, and a thiazole ring are preferable. Each of these rings may further have a substituent described later.

  In the partial structure represented by the general formula (1), the ring formed by E1f to E1k represents a 6-membered aromatic hydrocarbon ring or a 6-membered aromatic heterocycle.

  Examples of the 6-membered aromatic hydrocarbon ring formed by E1f to E1k include a benzene ring. Furthermore, you may have the substituent mentioned later.

  Examples of the 6-membered aromatic heterocycle formed by E1f to E1k include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring.

  Each of these rings may further have a substituent described later.

  In the partial structure represented by the general formula (1), the ring formed by E1l to E1q represents a 6-membered aromatic hydrocarbon ring or a 6-membered aromatic heterocycle.

  In the partial structure represented by the general formula (1), the 6-membered aromatic hydrocarbon ring formed by E1l to E1q represents a benzene ring. The benzene ring may further have a substituent described later. Examples of the 6-membered aromatic heterocycle formed by E1l to E1q include a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring.

  In the partial structure represented by the general formula (1), examples of the substituent represented by R1a to R1i include an alkyl group (for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a tert-butyl group, a pentyl group, Hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group, etc.), alkenyl group (for example, vinyl group, allyl group, etc.), alkynyl group ( For example, ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (also called 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 group, fluorenyl group, phenanthryl group, Denyl group, pyrenyl group, biphenylyl group, etc.), aromatic heterocyclic group (for example, pyridyl group, pyrimidinyl group, furyl group, pyrrolyl group, imidazolyl group, benzoimidazolyl group, pyrazolyl group, pyrazinyl group, triazolyl group (for example, 1, 2,4-triazol-1-yl group, 1,2,3-triazol-1-yl group, etc.), oxazolyl group, benzoxazolyl group, thiazolyl group, isoxazolyl group, isothiazolyl group, furazanyl group, thienyl group, A quinolyl group, a benzofuryl group, a dibenzofuryl group, a benzothienyl group, a dibenzothienyl group, an indolyl group, a carbazolyl group, a carbolinyl group, a diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group 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, pentyl) Oxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxy group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (Eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group ( For example, phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, Phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group) , Dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, Til 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 ( For example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonyl) Amino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylca Bonylamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexyl) Aminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido) Group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pi Lysylaminoureido group, etc.), sulfinyl group (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group) Group), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group or heteroarylsulfonyl group (for example, phenyl) Sulfonyl group, naphthylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butyl) Mino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom), fluorinated carbonization Hydrogen group (for example, fluoromethyl group, trifluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxy group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group) , Triphenylsilyl group, phenyldiethylsilyl group, etc.). These substituents may be further substituted with the above substituents. A plurality of these substituents may be bonded to each other to form a ring.

(Electron donating group (electron donating substituent))
In the compound containing the partial structure represented by the general formula (1) according to the present invention, R1a to R1i represent a hydrogen atom or a substituent, and at least one of R1c to R1f represents an electron donating substituent. Represent.

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

Specific examples of the substituent having an electron donating property include a hydroxy group (−0.37), an alkoxy group (for example, a methoxy group (−0.27), an ethoxy group (−0.24), a propyloxy group (− 0.25) etc.), amino group (−0.66), dimethylamino group (−0.83), methylamino group (−0.84), alkyl group (for example, methyl group (−0.17), Ethyl group (−0.15), propyl group (−0.13), t-butyl group (−0.20), butyl group (−0.16), etc.), cycloalkyl group (for example, cyclopropyl group) (−0.21), cyclobutyl group (−0.15), cyclopentyl group (−0.02) cyclohexyl group (−0.22), etc.), aryl groups (for example, phenyl group (−0.01) etc.) An aryloxy group (for example, a phenyloxy group (−0 03), etc.), hydroxyl amino group _{(-0.34), - NHNH 2 (} -0.55), - NHCONH 2 (-0.24), - NHC 2 H 5 (-0.61), - NHCONHC 2 H ₅ (−0.26), —NHC ₄ H ₉ (−0.51), —NHC ₆ H ₅ (−0.40), —N═CHC ₆ H ₅ (−0.55), —OCH ₂ COOH (−0.33), —OCH (CH ₃ ) ₂ (−0.45), —OC ₅ H ₁₁ (−0.34), —OCH ₂ C ₆ H ₅ (−0.42). .

  Among the above, the electron donating group preferably used includes an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, and an aryloxy group.

  For the Hammett σp value, for example, the following documents can be referred to.

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

(Group 8-10 transition metal elements in the periodic table represented by M)
As a metal used for forming a metal complex having a partial structure represented by any one of the general formulas (1), (4) or (5) according to the present invention, a transition of group 8 to 10 of the periodic table of elements Metal elements (also simply referred to as transition metals) are used, among which iridium and platinum are preferable transition metal elements.

  Moreover, in this invention, the partial structure represented by either the said General formula (4) or (5) is preferable among the partial structures represented by the said General formula (1).

<< Partial structure represented by either general formula (4) or (5) >>
The partial structure represented by either general formula (4) or (5) according to the present invention will be described.

  In the partial structure represented by either general formula (4) or (5), each of the substituents represented by R1a to R1b and R1g to R1i is R1a in the partial structure represented by general formula (1). It is synonymous with the substituent respectively represented by -R1i.

  In the partial structure represented by either the general formula (4) or (5), R1d represents an alkyl group, an aryl group, an alkoxy group, or an aryloxy group, and these groups are represented by the general formula (1). It is synonymous with the alkyl group, aryl group, alkoxy group or aryloxy group mentioned as the electron-donating substituent represented by at least one of R1c to R1f.

<< Preferred embodiment of the group represented by R1b >>
As group represented by R1b which is a substituent of the compound (metal complex) containing the partial structure represented by either general formula (1) or general formula (4) or general formula (5) according to the present invention Is preferably a group represented by the general formula (6), more preferably a group represented by the general formula (7), and particularly preferably a group represented by the general formula (8). is there.

  Hereinafter, groups represented by general formula (6) to general formula (8) will be described.

(Group represented by general formula (6))
In the general formula (6), an atomic group necessary for forming a 6-membered aromatic hydrocarbon ring or a 5-membered to 6-membered aromatic heterocycle represented by Z is represented by the formula (1) to ( The partial structure represented by 3) has the same meaning as the 6-membered aromatic hydrocarbon ring or 5-membered or 6-membered aromatic heterocycle formed by E1f to E1k.

  In the general formula (6), the substituent represented by Rb has the same meaning as the substituents represented by R1a to R1i in the partial structure represented by any of the general formulas (1) to (5). .

  In the general formula (6), a substituent having a steric parameter value (Es value) represented by Ra of −0.5 or less will be described in detail below. In addition, the substituent is preferably bonded to the atom adjacent to A constituting the 6-membered aromatic hydrocarbon ring or 5-membered to 6-membered aromatic heterocycle formed by the Z. More preferably, the electron donating group is preferable.

  Hereinafter, the three-dimensional parameter value (Es value) will be described.

(3D parameter value (Es value))
In the present invention, the Es value is a steric parameter derived from chemical reactivity. The smaller this value, the more sterically bulky substituent can be said.

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

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

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

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

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

  In the general formula (6), the group represented by Ra has a steric parameter (Es value) of −0.5 or less, preferably −7.0 to −0.6, particularly preferably − 7.0-1.0.

  In the present invention, when a steric parameter value (Es value) is -0.5 or less, for example, a keto-enol tautomer may exist in Z, the keto moiety has an Es value as an enol isomer. It is converted.

  Even when other tautomerism exists, the Es value is converted by the same conversion method. Furthermore, the substituent having an Es value of −0.5 or less is preferably an electron-donating substituent in terms of electronic effect.

  In the present invention, among the groups represented by the general formula (6), a group represented by the general formula (7) is more preferable.

<< General formula (7) >>
In the general formula (7), the substituent represented by Ra and having a steric parameter value (Es value) of −0.5 or less is the steric parameter value (Es value) represented by Ra in the general formula (6). Is synonymous with a substituent of -0.5 or less.

  In the general formula (7), the substituent represented by Rb has the same meaning as the substituents represented by R1a to R1i in the partial structure represented by any one of the general formulas (1) to (5). .

  In the present invention, among the groups represented by the general formula (7), the group represented by the general formula (8) is particularly preferable among the groups represented by the general formula (8).

<< General formula (8) >>
In the general formula (8), the substituents each represented by Ra and Rc and having a steric parameter value (Es value) of −0.5 or less are the steric parameter values represented by Ra in the general formula (6) ( (Es value) is synonymous with a substituent of -0.5 or less.

  In the general formula (8), the substituent represented by Rb has the same meaning as the substituents represented by R1a to R1i in the partial structure represented by any one of the general formulas (1) to (5). .

(Ligand applicable to formation of metal complex according to the present invention)
In forming the metal complex (metal complex compound) according to the present invention, a conventionally known ligand described later can be used in combination as necessary. Moreover, as what is called a ligand, the said trader can use together a well-known ligand (it is also called a coordination compound) as a ligand as needed.

  There are various known ligands used in conventionally known metal complexes. For example, “Photochemistry and Photophysics of Coordination Compounds” Springer-Verlag H. Published by Yersin in 1987, “Organometallic Chemistry-Fundamentals and Applications-” Liu Huabo Company, Akio Yamamoto, published in 1982, etc. (for example, halogen ligands (preferably chlorine ligands), Nitrogen heterocyclic ligands (for example, bipyridyl, phenanthroline, etc.) and diketone ligands).

  Hereinafter, a compound (also referred to as a metal complex or a metal complex compound) containing (also referred to as) a partial structure represented by a partial structure represented by any one of the general formulas (1) to (5) according to the present invention Although a specific example is shown, this invention is not limited to these.

  These metal complexes are described in, for example, Organic Letter, Vol. 3, no. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), Organic Letter, Vol. 8, no. 3, pages 415 to 418 (2006), and further by applying methods such as references described in these documents.

  Although the synthesis example of the metal complex based on this invention is shown below, this invention is not limited to these.

<< Synthesis Example 1: Synthesis of Exemplified Compound 1-3 >>
Step 1: Synthesis of complex A In a 100 ml four-necked flask, 2.0 g (0.005707 mol) of 3-mesityl-6-methylimidazo [1,2-f] phenanthridine, 13 ml of 2-ethoxyethanol, and 4 ml of water were added. Put on, put nitrogen blowing tube, thermometer, condenser and set on oil bath stirrer.

To this, 0.80 g (0.002269 mol) of IrCl ₃ 3H ₂ O and 0.23 g (0.002273 mol) of triethylamine were added, and the mixture was boiled and refluxed at an internal temperature of about 100 ° C. for 24 hours to complete the reaction. It was.

  After completion of the reaction, the reaction mixture was cooled to room temperature, methanol was added, and the precipitated solid was collected by filtration. The obtained solid was thoroughly washed with methanol and dried to obtain 1.55 g (72.3%) of complex A.

Step 2: Synthesis of complex B In a 100 ml four-necked flask, 1.55 g (0.0008364 mol) of complex A, 0.34 g of acetylacetone, 1.55 g of sodium carbonate and 37 ml of 2-ethoxyethanol were introduced, and nitrogen was blown into the flask. A tube, a thermometer and a condenser were attached and set on an oil bath stirrer.

  The mixture was heated and stirred for 2 hours at an internal temperature of 80 ° C to 90 ° C. After completion of the reaction, the reaction solution was cooled to room temperature, methanol was added to the reaction solution, and the precipitated crystals were filtered. The crystals were washed with 30 ml of water and 10 ml of MeOH and dried to obtain 1.35 g of complex B (81.3%).

Step 3: Synthesis of Exemplary Compound 1-3 In a 100 ml four-necked flask, 1.2 g (0.001212 mol) of complex B, 0.37 g of 3-mesityl-6-methylimidazo [1,2-f] fe Nantridine and 60 ml of ethylene glycol were added, and a nitrogen blowing tube, a thermometer, and an air cooling tube were attached and set on an oil bath stirrer. The reaction was terminated by heating and stirring for 2 hours at an internal temperature of 170 ° C. to 180 ° C. under nitrogen flow.

  After completion of the reaction, the mixture was cooled to room temperature, methanol was added and dispersed, and the crystals were collected by filtration to obtain 1.31 g of crude crystals.

  After the crude crystals were purified by column chromatography (developing solvent dichloromethane), the obtained crystals were suspended in methanol and the crystals were collected by filtration to obtain 1.23 g (82.0%) of Exemplary Compound 1-3.

Of the obtained crystals, 0.95 g was purified by sublimation with a sublimation purification apparatus (P-100, manufactured by ALS Technology) at a degree of vacuum of 7.1 × 10 ⁻⁴ Pa to 2.4 × 10 ⁻⁴ Pa. 0.58g (sublimation yield 61%) of exemplary compound 1-3 was obtained.

The structure of the obtained exemplary compound 1-3 was confirmed using ¹ H-NMR (nuclear magnetic resonance spectrum). Measurement conditions, chemical shift of each peak of the obtained spectrum, proton number, etc. are shown below.

¹ H-NMR (400 MHz, CD ₂ Cl ₂ )
Measuring apparatus: JEOL JNM-AL400 (400 MHz): manufactured by JEOL Ltd. Spectrum attribution (chemical shift δ, proton number, peak shape)
8.32 (1H, d), 7.63 (1H, d), 7.22 (1H, dd), 7.14 (1H, t), 7.01 (3H, m), 6.91 (1H) , S) 6.85 (1H, s), 2.36 (3H, s), 2.00 (3H, s), 1.86 (1H, s)
In addition, the emission wavelength in the solution of exemplary compound 1-3 was 463 nm (the emission wavelength was measured in 2-methyltetrahydrofuran).
In the present invention, the emission wavelength of the exemplified compound was measured as follows. First, an absorption spectrum of the exemplary compound is measured, and an absorption maximum wavelength in the range of 300 nm to 350 nm is set as excitation light.

  Using the set excitation light, the emission wavelength is measured with a fluorometer F-4500 (manufactured by Hitachi, Ltd.) while performing nitrogen bubbling.

  In addition, although there is no restriction | limiting in the solvent which can be used, 2-methyltetrahydrofuran, a dichloromethane, etc. are used preferably from a soluble viewpoint of a compound.

The concentration at the time of measurement is preferably sufficiently diluted, and specifically, it is preferably measured in the range of 10 ⁻⁶ mol / l to 10 ⁻⁴ mol / l.

  Moreover, there is no restriction | limiting in particular as temperature at the time of measurement, However, Generally, it is preferable that temperature setting of the range of room temperature-77K is performed.

(Charge transport layer (also called charge transport layer))
The charge transport layer according to the present invention will be described.

  Note that in the present invention, the charge represents electrons, holes (also referred to as holes), and the like.

  As a containing layer of the compound (metal complex) having a partial structure represented by the general formula (1), or the general formula (4) or the general formula (5) according to the present invention, a charge transporting layer ( The charge transport layer is not particularly limited, and the charge transport layer is provided on the anode side with respect to the light emitting layer (referred to as the first charge transport layer), and is provided on the cathode side with respect to the light emitting layer. Either embodiment (also referred to as a second charge transport layer) can be employed.

  When the charge transport layer is provided on the anode side of the light emitting layer (also referred to as a first charge transport layer), the charge transport layer is preferably an electron blocking layer or a light emitting layer, and the charge transport layer is more than the light emitting layer. When provided on the cathode side (also referred to as the second charge transport layer), the charge transport layer is preferably a light emitting layer or a hole blocking layer, and more preferably, the charge transport layer is a light emitting layer or a hole blocking layer. The light emitting layer is particularly preferable.

  When contained in the light emitting layer, it can be used as a light emitting dopant in the light emitting layer to increase the efficiency of the external extraction quantum efficiency of the organic EL device of the present invention (higher brightness) and increase the light emission lifetime. it can.

  By using such a metal complex as an organic EL element material, it was possible to provide an organic EL element, a lighting device, and a display device that exhibit high luminous efficiency and have a long emission lifetime.

  The constituent layers of the organic EL element of the present invention will be described in detail below.

<< Constituent layers of organic EL elements >>
The constituent layers of the organic EL element of the present invention will be described. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / electron transport layer / cathode (ii) Anode / hole transport layer / light emitting layer / electron transport layer / cathode (iii) Anode / hole transport layer / light emitting layer / hole blocking layer / electron Transport layer / cathode (iv) Anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode (v) Anode / anode buffer layer / hole transport layer / light emitting layer / hole Blocking layer / electron transport layer / cathode buffer layer / cathode (vi) Anode / hole transport layer / electron block layer / light emitting layer / hole block layer / electron transport layer / cathode In the organic EL device of the present invention, blue light emission The light emission maximum wavelength of the layer is preferably in the range of 430 nm to 480 nm, the green light emission layer is preferably a monochromatic light emitting layer having a light emission maximum wavelength in the range of 510 nm to 550 nm, and the red light emission layer is in the range of the light emission maximum wavelength of 600 nm to 640 nm. This is a display device using these. It is preferred. Alternatively, a white light emitting layer may be formed by laminating at least three light emitting layers. Further, a non-light emitting intermediate layer may be provided between the light emitting layers. The organic EL element of the present invention is preferably a white light emitting layer, and is preferably a lighting device using these.

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

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

  The total film thickness of the light emitting layer is not particularly limited, but from the viewpoint of improving the uniformity of the film, preventing unnecessary application of high voltage during light emission, and improving the stability of the emission color with respect to the drive current. It is preferable to adjust in the range of 2 nm to 5 μm, more preferably in the range of 2 nm to 200 nm, and particularly preferably in the range of 10 nm to 20 nm.

  For the production of the light-emitting layer, a light-emitting dopant or a host compound, which will be described later, is formed by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink-jet method. it can.

  The light emitting layer of the organic EL device of the present invention preferably contains a light emitting host compound and at least one kind of light emitting dopant (such as a phosphorescent dopant (also referred to as a phosphorescent dopant) or a fluorescent dopant).

(Host compound (also called luminescent host))
The host compound used in the present invention will be described.

  Here, the host compound in the present invention is a phosphorescent quantum yield of phosphorescence emission at a room temperature (25 ° C.) having a mass ratio of 20% or more in the compound contained in the light emitting layer. Is defined as a compound of less than 0.1.

  The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in a layer is 20% or more among the compounds contained in a light emitting layer.

  As the host compound, 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 light emission dopants mentioned later, and, thereby, arbitrary luminescent colors can be obtained.

  The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (deposition polymerization property). A light emitting host), or one or more compounds such as the material C may be used.

  Although the specific example of the host compound preferably used for this invention below is shown, this invention is not limited to these.

  As a known host compound that may be used in combination, 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.

  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.

(Luminescent dopant)
The light emitting dopant according to the present invention will be described.

  As the light-emitting dopant according to the present invention, a fluorescent dopant (also referred to as a fluorescent compound) or a phosphorescent dopant (also referred to as a phosphorescent emitter, a phosphorescent compound, a phosphorescent compound, or the like) can be used. From the viewpoint of obtaining an organic EL device with high luminous efficiency, the light emitting dopant used in the light emitting layer or the light emitting unit of the organic EL device of the present invention (sometimes simply referred to as a light emitting material) contains the above host compound. At the same time, it is preferable to contain a phosphorescent dopant.

  In addition, the compound (also referred to as having) a partial structure represented by the partial structure represented by any one of the general formulas (1) to (5) according to the present invention (also referred to as a metal complex or a metal complex compound) Is preferably used in the light emitting layer in the constituent layers of the organic EL device of the present invention, and is preferably used as a light emitting dopant in the light emitting layer, and more preferably used as a phosphorescent dopant. That is.

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

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

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

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

  The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL device.

  The phosphorescent dopant is preferably a complex compound containing a group 8-10 metal in the periodic table of elements, more preferably an iridium compound, an osmium compound, a platinum compound (platinum complex compound), or a rare earth complex. Of these, iridium compounds are most preferred.

  Further, a compound (also referred to as having) a partial structure represented by the partial structure represented by any one of the general formulas (1) to (5) according to the present invention (both a metal complex and a metal complex compound) Examples of the compound that can be used in combination with the compound described in the following patent publications.

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

  Some specific examples are shown below.

(Fluorescent dopant (also called fluorescent compound))
Fluorescent dopants (fluorescent compounds) include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes Examples thereof include dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

  Next, a charge transport layer used as a constituent layer of the organic EL device of the present invention, that is, an injection layer, a blocking layer, an electron transport layer, and the like will be described.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, it exists between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer. May be.

  The injection layer is a layer provided between the electrode and the organic layer for lowering the driving voltage and improving the light emission luminance. “Organic EL element and its forefront of industrialization (published by NTT Corporation on November 30, 1998)” Part 2 Chapter 2 “Electrode Materials” (pages 123 to 166) in detail, there are 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. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specifically, strontium, aluminum, etc. Metal buffer layer typified by lithium, alkali metal compound buffer layer typified by lithium fluoride, alkaline earth metal compound buffer layer typified by magnesium fluoride, oxide buffer layer typified by aluminum oxide, etc. . The buffer layer (injection layer) is preferably a very thin film, and the film thickness is preferably in the range of 0.1 nm to 5 μm although it depends on the material.

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

  The hole blocking layer has a function of an electron transport layer in a broad sense, and is made of a hole blocking material that has a function of transporting electrons and has a remarkably small ability to transport holes. The probability of recombination of electrons and holes can be improved by blocking.

  Moreover, the structure of the electron carrying layer mentioned later 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 contains the carbazole derivative, carboline derivative, diazacarbazole derivative (one in which one of the carbon atoms constituting the carboline ring of the carboline derivative is replaced with a nitrogen atom) mentioned as the host compound. It is preferable to do.

  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 by the following method, for example.

  (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 The ionization potential can be obtained as a value obtained by rounding off the second decimal place of the value (eV unit converted value) calculated by performing structural 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 method known as ultraviolet photoelectron spectroscopy can be suitably used by using a low energy electron spectrometer “Model AC-1” manufactured by Riken Keiki Co., Ltd.

  In addition, the hole blocking layer contains a compound that includes (also has) a partial structure represented by the partial structure represented by any one of the general formulas (1) to (5) according to the present invention. It is also possible.

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

  The film thickness of the hole blocking layer and the electron transport layer according to the present invention is preferably 3 nm to 100 nm, and more preferably 5 nm to 30 nm.

  In addition, the electron blocking layer contains a compound containing (or having) a partial structure represented by the partial structure represented by any one of the general formulas (1) to (5) according to the present invention. Is also possible.

《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.

  The above-mentioned materials can be used as the hole transport material, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ', N'-tetraphenyl-4,4'-diaminophenyl; N, N'-diphenyl-N, N'- Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' − (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and also two of those described in US Pat. No. 5,061,569. Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8 are linked in a starburst type ( MTDATA) and the like.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

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

  The hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. it can.

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

  Alternatively, a hole transport layer having a high p property doped with impurities can be used. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J. 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.

《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 as a single layer or a plurality of layers.

  Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the light emitting layer on the cathode side is injected from the cathode. As long as it has a function of transferring electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, nitro-substituted fluorene derivatives, diphenylquinone derivatives Thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives and the like.

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

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

  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 terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and an inorganic semiconductor such as n-type-Si, n-type-SiC, etc. as in the case of the hole injection layer and hole transport layer Can also be used as an electron transporting material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method.

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

  Further, an electron transport layer having a high n property doped with impurities can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

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

"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 nm to 1000 nm, preferably 10 nm to 200 nm.

"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 a 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 nm 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.

  Moreover, after producing the said metal by the film thickness of 1 nm-20 nm to a cathode, the transparent or semi-transparent cathode can be produced by producing the electroconductive transparent material quoted by description of the anode on it, By applying this, an element in which both the anode and the cathode are transmissive can be manufactured.

《Support substrate》
As a support substrate (hereinafter also referred to as a substrate, substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention, there is no particular limitation on the type of glass, plastic, etc., and it is transparent. May be opaque. When extracting light from the support substrate side, the support substrate is preferably transparent.

  Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film. A particularly preferable support substrate is a resin film capable of giving flexibility to the organic EL element.

  Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfones Cycloolefin resins such as polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylate, Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Can be mentioned.

On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed. 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 ml / (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, more preferably 5% or more.

  Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  In addition, a hue improvement filter such as a color filter may be used in combination, or a color conversion filter that converts the emission color from the organic EL element into multiple colors using a phosphor. In the case of using a color conversion filter, the λmax of light emission of the organic EL element is preferably 480 nm or less.

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

  In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned.

Furthermore, the polymer film has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured in (1) is 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 element of the present invention is processed on the light extraction side of the substrate, for example, so as to provide a microlens array-like structure, or in combination with a so-called condensing sheet, for example, with respect to a specific direction, for example, the element emission 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 arranged two-dimensionally 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.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport 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 film thickness of 1 μm or less, preferably 10 nm to 200 nm, to form an anode.

  Next, organic compound thin films such as a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are organic EL element materials, are formed thereon.

  As a method for forming each of these layers, there are a vapor deposition method, a wet process (spin coating method, casting method, ink jet method, printing method) and the like as described above, but it is easy to obtain a homogeneous film and it is difficult to generate pinholes. In view of the above, film formation by a coating method such as a spin coating method, an ink jet method, or a printing method is preferable in the present invention.

  Examples of the liquid medium for dissolving or dispersing the organic EL material include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, halogenated hydrocarbons such as dichlorobenzene, toluene, xylene, mesitylene, cyclohexylbenzene and the like. Aromatic hydrocarbons, 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 these layers are formed, a thin film made of a cathode material is formed thereon by 1 μm or less, preferably by a method such as vapor deposition or sputtering so that the film thickness is in the range of 50 nm to 200 nm. By providing, a desired organic EL element can be obtained.

  In addition, it is also possible to reverse the production order and produce the cathode, the electron injection layer, the electron transport layer, the light emitting layer, the hole transport layer, the hole injection layer, and the anode in this order. When a DC voltage is applied to the multicolor display device thus obtained, light emission can be observed by applying a voltage of about 2 V to 40 V with the anode as + and the cathode as-. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

<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 device may be patterned. 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 the total CS-1000 (manufactured by Konica Minolta Sensing) 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.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. The structures of the compounds used in the following examples are shown below.

Example 1
<< Measurement of phosphorescence lifetime of exemplary compounds >>
<< Creation of element 1-1 >>
A quartz substrate of 100 mm × 100 mm × 1.1 mm was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

  This quartz substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of H-1 is placed as a host compound in a molybdenum resistance heating boat, and 100 mg of compound A is placed in another molybdenum resistance heating boat as a vacuum deposition. Attached to the device.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing H-1 and Ir-12 (FIr (pic)) was energized and heated, and the deposition rate was 0.2 nm / second, respectively. Co-evaporated on the hole transport layer at 0.018 nm / second to provide a light emitting layer with a thickness of 40 nm.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

  The non-light-emitting surface of each organic EL element after fabrication is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photo-curing adhesive (LUX Track LC0629B) is applied, stacked on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, as shown in FIGS. Such a lighting device was formed and evaluated.

<Measurement of phosphorescence lifetime>
The manufactured quartz substrate was irradiated with an N ₂ gas laser having a wavelength of 337 nm at an output of 10 Hz, and the phosphorescence lifetime when excited was measured.

  The phosphorescence lifetime was measured with a picosecond fluorescence lifetime measuring device C4780 manufactured by Hamamatsu Photonics Co., Ltd.

  The obtained results are shown in Table 2.

  From Table 2, the element containing the compound containing the partial structure represented by any one of the general formulas (1) to (5) according to the present invention is more phosphorous than the element containing the comparative compounds A and B. It was found that the light lifetime was short.

Example 2
<< Preparation of Organic EL Element 2-1 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD was put in a molybdenum resistance heating boat, and 200 mg of H-1 as a host compound was put in another molybdenum resistance heating boat, Put 200 mg of BAlq in another molybdenum resistance heating boat, put 100 mg of Ir-12 (FIr (pic)) in another resistance heating boat made of molybdenum, and put 200 mg of Alq ₃ in another resistance heating boat made of molybdenum. Attached to the vapor deposition equipment.

Next, after reducing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat containing α-NPD was heated by heating, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. The hole transport layer was provided.

  Furthermore, the heating boat containing H-1 and Ir-12 (FIr (pic)) was energized and heated, and deposited on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively. Co-evaporated to provide a light emitting layer with a thickness of 40 nm. In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Further, the heating boat containing BAlq was energized and heated, and was deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer.

In addition, the heating boat containing Alq ₃ is further energized and heated, and deposited on the hole blocking layer at a deposition rate of 0.1 nm / second to further provide an electron transport layer having a thickness of 40 nm. It was.

  In addition, the substrate temperature at the time of vapor deposition was room temperature. Subsequently, 0.5 nm of lithium fluoride and 110 nm of aluminum were deposited to form a cathode, and an organic EL element 2-1 was produced.

  The non-light-emitting surface of each organic EL element after fabrication is covered with a glass case, a 300 μm thick glass substrate is used as a sealing substrate, and an epoxy photo-curing adhesive (LUX Track LC0629B) is applied, stacked on the cathode and brought into close contact with the transparent support substrate, irradiated with UV light from the glass substrate side, cured and sealed, as shown in FIGS. Such a lighting device was formed and evaluated.

  FIG. 3 shows a schematic diagram of the lighting device, in which the organic EL element 101 is covered with a glass cover 102 (note that the sealing operation with the glass cover is performed without bringing the organic EL element 101 into contact with the atmosphere. (It was performed in a glove box under an atmosphere (under an atmosphere of high-purity nitrogen gas having a purity of 99.999% or more)).

  4 shows a cross-sectional view of the lighting device. In FIG. 2, 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.

<< Production of Organic EL Elements 2-2 to 2-21 >>
In the production of the organic EL element 2-1, organic EL elements 2-2 to 2-21 were produced in the same manner except that the light emitting host and the light emitting dopant material were changed as shown in Table 3.

<< Evaluation of Organic EL Elements 2-1 to 2-21 >>
The organic EL elements 2-1 to 2-21 produced as described below were evaluated, and the results are shown in Table 3.

(External quantum efficiency)
External quantum efficiency (%) was measured when a ^2.5 mA / cm ² constant current was applied to the produced organic EL element at 23 ° C. in a dry nitrogen gas atmosphere.

  For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used in the same manner.

  The measurement results of the external extraction quantum efficiency in Table 3 were expressed as relative values when the measurement value of the organic EL element 2-1 was 100.

(Half life)
The half-life was evaluated according to the measurement method shown below.

Each organic EL device driven with a constant current at a current giving an initial luminance 1000 cd / ^{m 2,} obtains the time to be 1/2 (500cd / ^{m 2)} of the initial luminance, which was used as a measure of the half-life.

  The half life was expressed as a relative value when the comparative organic EL element 2-1 was set to 100.

(Initial deterioration)
The initial deterioration was evaluated according to the measurement method shown below.

  When the half-life was measured, the time required for the luminance to reach 90% was measured and used as a measure of initial deterioration.

  The initial deterioration was 100 for the comparative organic EL element 2-1.

  The initial deterioration was calculated based on the following formula.

Initial deterioration = (luminance 90% arrival time of organic EL element 1-1) / (luminance 90% arrival time of each element) × 100
In the evaluation, the smaller the initial deterioration value, the smaller the initial deterioration.

(Dark spot)
The light emitting surface when each organic EL element was continuously lit under a constant current condition of ^2.5 mA / cm ² at room temperature was visually evaluated.

  Specifically, rank evaluation was performed as follows for each element after 10 hours of continuous lighting time by visual evaluation by 10 people extracted at random.

×: When the number of confirmed dark spots is 5 or more Δ: When the number of confirmed dark spots is 3 to 4 ○: When the number of confirmed dark spots is 1 to 2 ◎: Dark spots It was assumed that the number of people who confirmed this was 0.

  The obtained evaluation results are shown in Table 3.

  From Table 3, it is clear that the organic EL device of the present invention using the compound represented by the general formula (1) according to the present invention has a high external extraction quantum efficiency and a long lifetime.

  In addition, in light of the results in Table 2, it is clear that the light emission lifetime of the device using the dopant having a short phosphorescence lifetime is longer than that of the device using the dopant having a long phosphorescence lifetime.

  Further, it can be seen that these elements have little initial deterioration and suppress the generation of dark spots.

Example 3
<Production of full-color display device>
(Production of blue light emitting element)
The organic EL element 2-16 of Example 1 was used as a blue light emitting element.

(Production of green light emitting element)
A green light emitting device was produced in the same manner as in the organic EL device 2-1 of Example 2, except that Ir-12 (FIr (pic)) was changed to Ir-1, and this was used as a green light emitting device.

(Production of red light emitting element)
A red light emitting device was produced in the same manner as in the organic EL device 2-1 of Example 2, except that Ir-12 (FIr (pic)) was changed to Ir-9, and this was used as a red light emitting device.

  The red, green, and blue light-emitting organic EL elements produced above were juxtaposed on the same substrate to produce an active matrix type full-color display device having a configuration as shown in FIG. In FIG. 2, 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, see FIG. 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, a high-brightness, high durability, and clear full-color moving image display can be obtained.

Example 4
<< Preparation of white light emitting element and white lighting device >>
The electrode of the transparent electrode substrate of Example 1 was patterned to 20 mm × 20 mm, and α-NPD was formed thereon with a thickness of 25 nm as a hole injection / transport layer in the same manner as in Example 1; The heated boat containing 1 and the boat containing Compound 1-3 and the boat containing Ir-9 are energized independently, and H-1 as a light emitting host and Illustrative Compound 1-3 as a light emitting dopant, and The vapor deposition rate of Ir-9 was adjusted to 100: 5: 0.6, vapor deposition was performed to a thickness of 30 nm, and a light emitting layer was provided.

Next, 10 nm of BAlq was deposited to provide a hole blocking layer. Furthermore, it was deposited Alq ₃ at 40nm an electron transporting layer.

  Next, as in Example 1, a square perforated mask having the same shape as the transparent electrode made of stainless steel was placed on the electron injection layer, and lithium fluoride 0.5 nm was used as the cathode buffer layer and aluminum 150 nm was used as the cathode. Vapor deposition and film formation were performed.

  This element was provided with a sealing can having the same method and the same structure as in Example 1, and a flat lamp as shown in FIGS. 3 and 4 was produced. When this flat lamp was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

Example 5
<< Production of White Light Emitting Element and White Lighting Device-2 >>
After patterning on a substrate (NH-Techno Glass NA-45) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

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

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of compound A dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. After irradiating with ultraviolet light for 180 seconds to perform photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to obtain a second hole transport layer (electron blocking layer).

  Next, using a solution of H-5 (60 mg), Exemplified Compound 4-1 (3.0 mg) and Ir-9 (3.0 mg) dissolved in 6 ml of toluene, spin coating method was performed at 1000 rpm for 30 seconds. To form a light emitting layer.

  Subsequently, this substrate was fixed to a substrate holder of a vacuum deposition apparatus, 200 mg of BAlq was put into a molybdenum resistance heating boat, and attached to the vacuum deposition apparatus.

The vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then heated by energizing the heating boat containing BAlq, and deposited on the light emitting layer at a deposition rate of 0.1 nm / sec. The electron transport layer was provided.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the white light emitting organic EL element was produced.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device. Further, similar devices were prepared using Exemplified Compounds 1-3, 2-21, 3-1, and 3-8 instead of Exemplified Compound 4-1. In the case where the light emitting material has a polymerizable group, ultraviolet light was irradiated for 180 seconds to perform photopolymerization / crosslinking, and then vacuum dried at 60 ° C. for 1 hour to obtain a light emitting layer. When these elements were energized, almost white light was obtained, and it was found that they could be used as a lighting device.

Example 6
<< Preparation of white light emitting element and white illumination device-3 >>
After patterning on a substrate (NA-45 manufactured by NH Techno Glass Co., Ltd.) formed by depositing 100 nm of ITO (indium tin oxide) on a 100 mm × 100 mm × 1.1 mm glass substrate as an anode, this ITO transparent electrode was provided. The transparent support substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

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

  This substrate was transferred to a nitrogen atmosphere, and a solution of 50 mg of compound D dissolved in 10 ml of toluene was formed on the first hole transport layer by spin coating at 1000 rpm for 30 seconds. After irradiating with ultraviolet light for 180 seconds to carry out photopolymerization / crosslinking, vacuum drying was performed at 60 ° C. for 1 hour to form a second hole transport layer.

  Next, a solution obtained by dissolving Compound E (60 mg), Ir-14 (3.0 mg), and Exemplified Compound 3-4 (3.0 mg) in 6 ml of toluene was used by spin coating method at 1000 rpm for 30 seconds. A film was formed. Irradiated with ultraviolet light for 15 seconds to cause photopolymerization / crosslinking, and further heated in vacuum at 150 ° C. for 1 hour to obtain a light emitting layer.

  Furthermore, a film in which compound F (20 mg) was dissolved in 6 ml of toluene was used to form a film by spin coating under conditions of 1000 rpm and 30 seconds. It was irradiated with ultraviolet light for 15 seconds to cause photopolymerization / crosslinking, and further heated in vacuum at 80 ° C. for 1 hour to form a hole blocking layer.

Subsequently, this substrate was fixed to a substrate holder of a vacuum vapor deposition apparatus, 200 mg of Alq ₃ was placed in a molybdenum resistance heating boat, and attached to the vacuum vapor deposition apparatus.

After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, energizing and heating the heating boat containing Alq ₃ , depositing on the hole blocking layer at a deposition rate of 0.1 nm / second, An electron transport layer having a thickness of 40 nm was provided.

  In addition, the substrate temperature at the time of vapor deposition was room temperature.

  Then, 0.5 nm of lithium fluoride and 110 nm of aluminum were vapor-deposited, the cathode was formed, and the white light emitting organic EL element was produced.

  When this element was energized, almost white light was obtained, and it was found that it could be used as a lighting device.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scanning line 6 Data line A Display part B Control part 107 Glass substrate with a transparent electrode 106 Organic EL layer 105 Cathode 102 Glass cover 108 Nitrogen gas 109 Water catching agent

Claims (11)

In an organic electroluminescence device containing at least one light emitting layer sandwiched between an anode and a cathode,
The light emitting layer has an organic layer containing at least one compound containing a partial structure represented by the following general formula (1).
[In formula, E1b-E1o and E1q represent a carbon atom, a nitrogen atom, an oxygen atom, or a sulfur atom respectively, and the frame | skeleton comprised by E1a-E1q has a total of 18 (pi) electrons. E1a and E1p are different from each other and represent a carbon atom or a nitrogen atom. R1a to R1b and R1g to R1i each represent a hydrogen atom or a substituent, R1c, R1e, and R1f are hydrogen atoms, and R1d represents an electron-donating isopropyl group or cyclohexyl group . M represents a group 8-10 transition metal element in the periodic table. ] The organic electroluminescent device according to claim 1, wherein the partial structure represented by the general formula (1) represents a partial structure represented by the following general formula (4) or (5).
[Wherein, R1a, R1b, R1g, R1h, R1i each represents a hydrogen atom or a substituent, and R1d represents an isopropyl group or a cyclohexyl group . M represents a group 8-10 transition metal element in the periodic table. ] 3. The organic electroluminescence device according to claim 1, wherein R 1 b is represented by the following general formula (6).
[Wherein, Z represents an atomic group necessary for forming a 6-membered aromatic hydrocarbon ring or a 5-membered or 6-membered aromatic heterocyclic ring, and A represents a nitrogen atom or a carbon atom. Ra represents a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 4. * Indicates a binding position. ] The organic electroluminescent device according to claim 3 , wherein the group represented by the general formula (6) is a group represented by the following general formula (7).
[In the formula, Ra represents a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 4. * Indicates a binding position. ] The organic electroluminescent device according to claim 4 , wherein the group represented by the general formula (7) is a group represented by the following general formula (8).
[In the formula, Ra and Rc each represent a substituent having a steric parameter value (Es value) of −0.5 or less. Rb represents a hydrogen atom or a substituent, and n represents an integer of 1 to 3. * Indicates a binding position. ] Wherein M is an organic electroluminescent device according to any one of claims 1 to 5, characterized in that represent a platinum or iridium. The organic electroluminescent device according to any one of claims 1 to 6, characterized in that the organic layer is formed using a wet process. A partial structure represented by the general formula (1) according to claim 1 or a compound containing the partial structure represented by the general formula (4) or (5) according to claim 2 An organic electroluminescent element material characterized by containing. The organic electroluminescence element material according to claim 8 , wherein M represents platinum or iridium. Display apparatus comprising the organic electroluminescent element of any one of claims 1-7. Lighting apparatus comprising the organic electroluminescent element of any one of claims 1-7.