JP5760941B2 - Organic electroluminescence element, display device and lighting device - Google Patents

Description

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

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

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

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

  In the techniques disclosed in Patent Documents 1 to 3, when light emission from excited singlet is used, the generation ratio of singlet excitons and triplet excitons is 1: 3, so that the generation probability of luminescent excited species Is 25% and the light extraction efficiency is about 20%, so the limit of the external extraction quantum efficiency (ηext) is set to 5%.

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

Further, studies using tris (2-phenylpyridine) iridium as a dopant have been made (for example, see Non-Patent Document 2). In addition, L ₂ Ir (acac), for example, (ppy) ₂ Ir (acac) (see, for example, Non-Patent Document 4) is used as a dopant, and tris (2- (p-tolyl) pyridine) iridium (Ir) is used as a dopant. (Ptpy) ₃ ), tris (benzo [h] quinoline) iridium (Ir (bzq) ₃ ), Ir (bzq) ₂ ClP (Bu) ₃ (for example, see Non-Patent Document 5), phenyl Studies using an iridium complex or the like using pyrazole as a ligand (for example, see Patent Document 4) have been conducted.

  In order to obtain high luminous efficiency, a hole transporting compound is used as a host of the phosphorescent compound (see, for example, Non-Patent Document 6).

  Further, various electron transporting materials are used as phosphorescent compound hosts by doping them with a novel iridium complex (see, for example, Non-Patent Document 4). Furthermore, studies have been made to improve luminous efficiency by introducing a hole blocking layer. (For example, refer nonpatent literature 5).

  Furthermore, in order to obtain high luminous efficiency, a combination of a carbazole compound and a phosphorescent compound has been studied (Patent Document 5).

  However, in the conventional organic electroluminescence device, improvement is desired in high light emission efficiency, particularly in blue light emission. Further improvements are also desired in terms of compatibility between emission luminance and lifetime.

Japanese Patent No. 3093796 Japanese Unexamined Patent Publication No. 63-264692 JP-A-3-255190 International Publication No. 04/085450 Pamphlet US 2002/0034656

M.M. A. Baldo et al. , Nature, 395, 151-154 (1998) M.M. A. Baldo et al. , Nature, 403, 17, 750-753 (2000) S. Lamansky et al. , J .; Am. Chem. Soc. , 123, 4304 (2001) M.M. E. Thompson et al. , The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) Moon-Jae Youn. 0 g, Tsutsuo Tsutsui et al. , The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu) Ikai et al. , The 10th International Workshop on Inorganic and Organic Electroluminescence (EL'00, Hamamatsu)

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic electroluminescence element, an illumination device, and a display device that have high emission luminance, high external extraction quantum efficiency, and long life. That is.

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

（式中、Ｒ_１は芳香族炭化水素基、芳香族複素環基、アルコキシ基、アミノ基またはアルキル基を表す。Ｚはベンゼン環を表す。ｎ１は０〜４の整数を表す。Ｂ_１〜Ｂ_５により形成される環は、各々置換基としてアルキル基、芳香族炭化水素基または芳香族複素環基を有するイミダゾール環を表す。Ｍ_１はイリジウム原子または白金原子を表す。Ｘ_１及びＸ_２は炭素原子、窒素原子または酸素原子を表し、Ｌ_１はＸ_１及びＸ_２と共に２座の配位子を形成する原子群を表す。ｍ１は１〜３の整数を表し、ｍ２は０〜２の整数を表すが、ｍ１＋ｍ２は２または３である。）

（式中、Ｒ₃及びＲ₄はアルキル基またはフェニル基を表す。ｎ３及びｎ４はそれぞれ０または１を表す。Ａ₁及びＡ₂は下記一般式（３）で表される基を表す。）

（式中、Ｚ_１及びＺ_２はベンゼン環またはピリジン環を表し、Ｚ_３は単なる結合手を表す。）

２．前記一般式（１）のＢ_１〜Ｂ_５により形成される環が有する置換基が、アルキル基、フェニル基またはチエニル基であることを特徴とする１に記載の有機エレクトロルミネッセンス素子。 1. Between a pair of electrodes, has a structure layer including a light emitting layer containing at least phosphorescent compound represented by the following general formula (1), at least one layer of said light-emitting layer is represented by the following general formula (2) An organic electroluminescent device characterized by containing a compound and emitting blue light . However, a combination of at least one phosphorescent compound selected from the following compounds 1 to 6 and the following compound B is excluded.

(In the formula, R ₁ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, an alkoxy group, an amino group, or an alkyl group. Z represents a benzene ring. N1 represents an integer of 0 to 4. B ₁ to. the ring formed by B _5, the .M ₁ representing Louis imidazole ring having a respective alkyl group as a substituent, an aromatic hydrocarbon group or an aromatic heterocyclic group representing the iridium atom or a platinum atom .X ₁ And X ₂ represents a carbon atom, a nitrogen atom, or an oxygen atom, L ₁ represents an atomic group that forms a bidentate ligand together with X ₁ and X _2. m1 represents an integer of 1 to 3, and m2 represents (It represents an integer of 0 to 2, but m1 + m2 is 2 or 3.)

(In the formula, R ₃ and R ₄ represent an alkyl group or a phenyl group. N3 and n4 each represent 0 or 1. A ₁ and A ₂ represent a group represented by the following general formula (3).)

(In the formula, Z ₁ and Z ₂ represent a benzene ring or a pyridine ring, and Z ₃ represents a simple bond.)

2 . B ₁ substituents wherein the ring has formed by .about.B ₅ is an alkyl group, an organic electroluminescence element according to 1, which is a phenyl group or a thienyl group of the general formula (1).

3 . 3. The organic electroluminescence device according to 1 or 2 , wherein M _{1 in the} general formula (1) is an iridium atom.

4 . 3. The organic electroluminescence device according to 1 or 2 , wherein M _{1 in the} general formula (1) is a platinum atom.

5 . At least one layer of the structure layer is a hole blocking layer, according to any one of 1-4, characterized by containing a compound represented by the general formula (2) in the hole blocking layer Organic electroluminescence device.

6 . The organic electroluminescent element according to any one of 1 to 5 , which emits white light.

7 . A display device comprising the organic electroluminescence element according to any one of 1 to 6 .

8 . It has an organic electroluminescent element as described in any one of 1-6 , The illuminating device characterized by the above-mentioned.

  According to the present invention, it is possible to provide an organic electroluminescence element, an illumination device, and a display device that have high emission luminance, high external extraction quantum efficiency, and a long lifetime.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. 4 is a schematic diagram of a display unit A. FIG. It is an equivalent circuit diagram of the drive circuit which comprises a pixel. It is a schematic diagram of the display apparatus by a passive matrix system. It is the schematic of an illuminating device. It is sectional drawing of an illuminating device.

  Hereinafter, the present invention will be described in detail.

[Phosphorescent Compound Represented by General Formula (1)]
The phosphorescent compound represented by the general formula (1) of the present invention will be described.

The group represented by R ₁ is also referred to as an aromatic hydrocarbon ring group (aromatic carbocyclic group, aryl group, etc., for example, phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, Anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, phenanthryl group, indenyl group, pyrenyl group, biphenylyl group, etc., aromatic heterocyclic group (eg, 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, benzooxazolyl group, Thiazolyl, isoxazolyl, isothiazolyl, furazanyl, thienyl, quinolyl, Zofuryl group, dibenzofuryl group, benzothienyl group, dibenzothienyl group, indolyl group, carbazolyl group, carbolinyl group, diazacarbazolyl group (one of the carbon atoms constituting the carboline ring of the carbolinyl group is replaced by a nitrogen atom) Quinoxalinyl group, pyridazinyl group, triazinyl group, quinazolinyl group, phthalazinyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy group, pentyloxy group, hexyloxy group, octyloxy group, dodecyl) Oxy group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethylhexylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group) Etc.), or An alkyl group (for example, methyl group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.);

  Of these groups, preferred is an alkyl group or an aryl group. More preferred is an unsubstituted alkyl group or aryl group.

Z is a benzene ring .

The ring formed by B ₁ .about.B ₅ is a Lee imidazole ring.

Further, substituents wherein the ring formed by B ₁ .about.B ₅ has an alkyl group, an aromatic hydrocarbon group or an aromatic heterocyclic group, each alkyl group represented by R _1, an aromatic hydrocarbon The group is synonymous with an aromatic heterocyclic group. Preferably, they are an alkyl group, a phenyl group, or a thienyl group.

L ₁ represents an atomic group that forms a bidentate ligand together with X ₁ and X ₂ . Specific examples of the bidentate ligand represented by X ₁ -L ₁ -X ₂ include, for example, substituted or unsubstituted phenylpyridine, phenylpyrazole, phenylimidazole, phenyltriazole, phenyltetrazole, pyrazabol and acetylacetone. Is mentioned. These groups may be further substituted with the above substituents.

  m1 represents an integer of 1 to 3, m2 represents an integer of 0 to 2, and m1 + m2 is 2 or 3. Among these, m2 is preferably 0.

M ₁ represents an iridium atom or a platinum atom, more preferably iridium.

これらの金属錯体は、例えば、Ｏｒｇａｎｉｃ Ｌｅｔｔｅｒ誌，ｖｏｌ３，Ｎｏ．１６，２５７９〜２５８１頁（２００１）、Ｉｎｏｒｇａｎｉｃ Ｃｈｅｍｉｓｔｒｙ，第３０巻，第８号，１６８５〜１６８７頁（１９９１年）、Ｊ．Ａｍ．Ｃｈｅｍ．Ｓｏｃ．，１２３巻，４３０４頁（２００１年）、Ｉｎｏｒｇａｎｉｃ Ｃｈｅｍｉｓｔｒｙ，第４０巻，第７号，１７０４〜１７１１頁（２００１年）、Ｉｎｏｒｇａｎｉｃ Ｃｈｅｍｉｓｔｒｙ，第４１巻，第１２号，３０５５〜３０６６頁（２００２年）、Ｎｅｗ Ｊｏｕｒｎａｌ ｏｆ Ｃｈｅｍｉｓｔｒｙ，第２６巻，１１７１頁（２００２年）、Ｅｕｒｏｐｅａｎ Ｊｏｕｒｎａｌ ｏｆ Ｏｒｇａｎｉｃ Ｃｈｅｍｉｓｔｒｙ，第４巻，６９５〜７０９頁（２００４年）、さらにこれらの文献中に記載の参考文献等の方法を適用することにより合成できる。 Specific examples of the phosphorescent compound represented by the general formula (1) of the present invention are given below, but the present invention is not limited to these.

These metal complexes are described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, pp. 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, Vol. 26, page 1171 (2002), European Journal of Organic Chemistry, Vol. 4, pages 695-709 (2004), and methods of references and the like described in these documents. It can be synthesized by applying.

[Compound represented by formula (2)]
Next, the compound represented by the general formula (2) will be described.

In general formula (2), _{R 3} and _{R 4} represents an alkyl group or a phenyl group. n3 and n4 represent the integer of 0-3. A ₁ and A ₂ represent a group represented by the following general formula (3).

[Group represented by general formula (3)]
Next, the group represented by the general formula (3) will be described.

In the general formula (3), _{Z 1} and _{Z 2} represents a benzene ring or a pyridine ring. Further, these benzene ring and pyridine ring may have a substituent.

Of the rings formed by Z ₁ , preferred is a pyridine ring.

Z ₃ represents a simple bond. A mere bond is a bond that directly bonds the connecting substituents together.

本発明に係る一般式（１）または（２）で表される化合物は、各々有機ＥＬ素子用材料（バックライト、フラットパネルディスプレイ、照明光源、表示素子、電子写真用光源、記録光源、露光光源、読み取り光源、標識、看板、インテリア、光通信デバイス等）等の用途に用いられるが、その他の用途としては、有機半導体レーザ用材料（記録光源、露光光源、読み取り光源光通信デバイス、電子写真用光源等）、電子写真用感光体材料、有機ＴＦＴ素子用材料（有機メモリ素子、有機演算素子、有機スイッチング素子）、有機波長変換素子用材料、光電変換素子用材料（太陽電池、光センサー等）等の広い分野に利用可能である。 Although the specific example of a compound represented by General formula (2) of this invention below is given, this invention is not limited to these.

The compounds represented by the general formula (1) or (2) according to the present invention are each an organic EL element material (backlight, flat panel display, illumination light source, display element, electrophotographic light source, recording light source, exposure light source). , Reading light source, sign, signboard, interior, optical communication device, etc., but other uses include organic semiconductor laser materials (recording light source, exposure light source, reading light source optical communication device, for electrophotography) Light source, electrophotographic photosensitive material, organic TFT element material (organic memory element, organic arithmetic element, organic switching element), organic wavelength conversion element material, photoelectric conversion element material (solar cell, photosensor, etc.) It can be used in a wide range of fields.

  Next, the constituent layers of the organic EL device of the present invention will be described in detail. In this invention, although the preferable specific example of the layer structure of an organic EL element is shown below, this invention is not limited to these.

(I) Anode / light emitting layer / 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 It is preferable that the hole transport layer is adjacent to the anode and the electron transport layer is adjacent to the cathode.

"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 the pattern accuracy is not required (about 100 μm or more) ), A pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. When light emission is extracted from the anode, it is desirable that the transmittance be greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

"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, Suitable are a magnesium / aluminum mixture, a magnesium / indium mixture, an aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, a lithium / aluminum mixture, aluminum and the like. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the emission luminance is advantageously improved.

  Moreover, after producing the said metal with a film thickness of 1-20 nm on a cathode, a 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.

  Next, an injection layer, a blocking layer, an electron transport layer, and the like used as a constituent layer of the organic EL element of the present invention 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.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. 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>
As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

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

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

  In this invention, it is preferable to contain the compound represented by General formula (2) mentioned above as a hole blocking material of a hole blocking layer. Thereby, it can be set as an organic EL element with much higher luminous efficiency. Further, the lifetime can be further increased.

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

<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.

(Host compound)
The light-emitting layer of the organic EL device of the present invention preferably contains the following host compound and phosphorescent compound (also referred to as phosphorescent compound). In the present invention, the general formula ( It is preferable to use the compound represented by 2). Thereby, the luminous efficiency can be further increased. Moreover, you may contain compounds other than the compound represented by General formula (2) as a host compound.

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

  Further, a plurality of known host compounds may be used in combination. 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. Further, by using a plurality of types of phosphorescent compounds, it is possible to mix different light emission, and thereby any light emission color can be obtained. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to illumination and backlight.

  As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are 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.

  The light emitting layer may further contain a host compound having a fluorescence maximum wavelength as a host compound. In this case, the energy transfer from the other host compound and the phosphorescent compound to the fluorescent compound allows the electroluminescence as the organic EL element to be emitted from the other host compound having the fluorescence maximum wavelength. A host compound having a fluorescence maximum wavelength is preferably a compound having a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield is preferably 10% or more, particularly preferably 30% or more. Specific host compounds having a maximum fluorescence wavelength include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, and pyrylium dyes. Perylene dyes, stilbene dyes, polythiophene dyes, and the like. The fluorescence quantum yield can be measured by the method described in 362 (1992, Maruzen) of Spectroscopic II of the Fourth Edition Experimental Chemistry Course 7.

(Phosphorescent compound (phosphorescent compound))
The material used for the light emitting layer (hereinafter referred to as a light emitting material) preferably contains a phosphorescent compound at the same time as the host compound. Thereby, it can be set as an organic EL element with higher luminous efficiency.

  The phosphorescent compound represented by the general formula (1) according to the present invention is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield. The compound is 0.01 or more at 25 ° C. The phosphorescent quantum yield is preferably 0.1 or more. The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescent compound used in the present invention only needs to achieve the phosphorescence quantum yield in any solvent.

  There are two types of light emission of phosphorescent compounds 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 compound. Energy transfer type to obtain light emission from the phosphorescent compound, and another one is that the phosphorescent compound becomes a carrier trap, carrier recombination occurs on the phosphorescent compound, and light emission from the phosphorescent compound is obtained. Although it is a trap type, in any case, it is a condition that the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

In the general formula (1), as the metal represented by M ₁ , a transition metal element of Group 8 to 10 of the periodic table (also simply referred to as a transition metal) is used, among which iridium and platinum are preferable, Iridium is preferred.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent compound is not particularly limited, and in principle, the emission wavelength obtained by selecting a central metal, a ligand, a ligand substituent, and the like. However, it is preferable that the phosphorescence emission wavelength of the phosphorescent compound has a maximum phosphorescence emission wavelength of 380 to 480 nm. Luminous efficiency can be further increased with such blue phosphorescent organic EL elements and white phosphorescent organic EL elements.

本発明の有機ＥＬ素子や本発明に係る化合物の発光する色は、「新編色彩科学ハンドブック」（日本色彩学会編、東京大学出版会、１９８５）の１０８頁の図４．１６において、分光放射輝度計ＣＳ−１０００（コニカミノルタセンシング社製）で測定した結果をＣＩＥ色度座標に当てはめたときの色で決定される。 In the present invention, other phosphorescent compounds can be used in combination with the phosphorescent compound represented by the general formula (1). Specific examples of phosphorescent compounds that can be used in combination are shown below, but the present invention is not limited thereto. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

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.

  The light emitting layer can be formed by forming the above compound 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. Although the film thickness as a light emitting layer does not have a restriction | limiting in particular, Usually, 5 nm-5 micrometers, Preferably it is chosen in the range of 5-200 nm. The light-emitting layer may have a single layer structure in which these phosphorescent compounds and host compounds are one type or two or more types, or may have a laminated structure including a plurality of layers having the same composition or different compositions.

《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, as well as two of those described in US Pat. No. 5,061,569 Having a condensed aromatic ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-308 4,4 ', 4 "-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 88 are linked in a starburst type ( MTDATA) and the like.

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

  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 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

《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 similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC can be used. A semiconductor can also be used as an electron transport material.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, 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 5-200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

<Substrate>
The organic EL device of the present invention is preferably formed on a substrate.

  The substrate (hereinafter also referred to as a substrate, substrate, support, etc.) that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic, etc. Although there is no restriction | limiting, As a board | substrate used preferably, glass, quartz, and a transparent resin film can be mentioned, for example. A particularly preferable substrate is a resin film that can give flexibility to the organic EL element.

  Examples of the resin film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, polycarbonate (PC), and cellulose. Examples include films made of triacetate (TAC), cellulose acetate propionate (CAP), and the like. On the surface of the resin film, an inorganic film, an organic film, or a hybrid film of both may be formed.

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

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

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

As a method for thinning the organic compound thin film, there are a vapor deposition method and a wet process (spin coating method, casting method, ink jet method, printing method) as described above, but it is easy to obtain a uniform film and a pinhole. From the point of being difficult to form, a vacuum deposition method, a spin coating method, an ink jet method, and a printing method are particularly preferable. Further, a different film forming method may be applied for each layer. When employing a vapor deposition method for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C., a degree of vacuum of 10 ⁻⁶ to 10 ⁻² Pa, and a vapor deposition rate of 0.01 to It is desirable to select appropriately within the range of 50 nm / second, substrate temperature −50 to 300 ° C., film thickness 0.1 nm to 5 μm, preferably 5 to 200 nm.

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

  The multicolor display device of the present invention is provided with a shadow mask only at the time of forming a light emitting layer, and the other layers are common, so patterning such as a shadow mask is unnecessary, and a vapor deposition method, a casting method, a spin coating method, an ink jet method on one side A film can be formed by a printing method or the like. When patterning is performed only on the light-emitting layer, the method is not limited, but a vapor deposition method, an inkjet method, and a printing method are preferable. In the case of using a vapor deposition method, patterning using a shadow mask is preferable.

  In 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 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. An alternating voltage may be applied. The alternating current waveform to be applied may be arbitrary.

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

  Examples of the display device and the display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in a car. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  The lighting device of the present invention includes household 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 sources of optical sensors. However, it is not limited to this.

  Moreover, you may use as an organic EL element which gave the organic EL element of this invention the resonator structure. Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.

<Display device>
The organic EL element of the present invention may be used as one kind of lamp for illumination or exposure light source, a projection device for projecting an image, or a display for directly viewing a still image or a moving image. It may be used as a device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using three or more organic EL elements of the present invention having different emission colors. Alternatively, it is possible to make a single color emission color, for example, white emission, into BGR using a color filter to achieve full color. Further, it is possible to convert the emission color of the organic EL to another color by using a color conversion filter, and in this case, λmax of the organic EL emission is preferably 480 nm or less.

  An example of a display device composed of the organic EL element of the present invention will be described with reference to the drawings.

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

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

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

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

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

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

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

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

  FIG. 3 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

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

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

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

  That is, the organic EL element 10 emits light by emitting the organic EL element 10 of each of the plurality of pixels 3 by providing the switching transistor 11 and the driving transistor 12 as active elements to the organic EL elements 10 of the plurality of pixels. Is going. Such a light emitting method is called an active matrix method. Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or by turning on / off a predetermined light emission amount by a binary image data signal. Good.

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

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

  FIG. 4 is a schematic diagram of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

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

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

  A combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials (light emitting dopants), a light emitting material that emits fluorescence or phosphorescence, and the light emitting material. Any combination of a dye material that emits the above light as excitation light may be used, but in the white organic electroluminescence device according to the present invention, a method of combining a plurality of light-emitting dopants is preferable.

  As a layer structure of an organic electroluminescence device for obtaining a plurality of emission colors, a method of having a plurality of emission dopants in one emission layer, a plurality of emission layers, and an emission wavelength in each emission layer And a method of forming minute pixels emitting light having different wavelengths in a matrix.

  In the white organic electroluminescence device according to the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is known so as to be suitable for the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.

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

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

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

Example 1
<< Production of Organic EL Elements 1-1 to 1-20 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate is fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD is put in a molybdenum resistance heating boat, and 200 mg of CBP as a host compound is put in another resistance heating boat made of molybdenum. 200 mg of bathocuproin (BCP) is put in a molybdenum resistance heating boat, 100 mg of comparative compound 1 is added as a phosphorescent compound in another molybdenum resistance heating boat, and 200 mg of Alq ₃ is put in another molybdenum resistance heating boat, and vacuum deposition is performed. Attached to the device.

Next, the pressure in the vacuum chamber is reduced to 4 × 10 ⁻⁴ Pa, and the heating boat containing α-NPD is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. Was provided. Further, the heating boat containing CBP and Comparative Compound 1 was energized and heated, and co-evaporated on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to provide a light emitting layer. . In addition, the substrate temperature at the time of vapor deposition was room temperature. Furthermore, the heating boat containing BCP was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer. Further, 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, and an electron transport layer having a thickness of 40 nm is further provided. It was. 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 organic EL element 1-1 was produced.

《有機ＥＬ素子１−１〜１−２０の評価》
以下のようにして、作製した有機ＥＬ素子１−１〜１−２０の評価を行った。 In the production of the organic EL device 1-1, except that CBP used as the host compound of the light emitting layer was replaced with a compound shown in Table 1, and Comparative Compound 1 used as a phosphorescent compound was replaced with a compound shown in Table 1. Organic EL devices 1-2 to 1-20 were produced by the same method as the organic EL device 1-1. The structure of the compound used above is shown below.

<< Evaluation of Organic EL Elements 1-1 to 1-20 >>
The produced organic EL elements 1-1 to 1-20 were evaluated as follows.

(Luminance)
The luminance (cd / m ² ) was determined using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing). The measurement result of luminance was expressed as a relative value with the measured value of the organic EL element 1-1 being 100.

(External quantum efficiency)
About the produced organic EL element, the external extraction quantum efficiency (%) when a ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used in the same manner. The measurement result of the external extraction quantum efficiency was expressed as a relative value with the measured value of the organic EL element 1-1 as 100.

The results obtained as described above are shown in Table 1.

Example 2
<< Production of Organic EL Elements 2-1 to 2-15 >>
Transparent support provided with this ITO transparent electrode after patterning on a substrate (NH45 manufactured by NH Techno Glass) made of ITO (indium tin oxide) with a thickness of 100 nm on a glass substrate of 100 mm × 100 mm × 1.1 mm as an anode The substrate was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes. This transparent support substrate was fixed to a substrate holder of a commercially available vacuum deposition apparatus, while 200 mg of α-NPD was put in a molybdenum resistance heating boat, and 200 mg of CBP was put in another molybdenum resistance heating boat as a host compound of the light emitting layer. In another molybdenum resistance heating boat, 200 mg of BCP is added as a hole blocking material. In another molybdenum resistance heating boat, 100 mg of Comparative Compound 1 is added as a phosphorescent compound of the light emitting layer, and in another molybdenum resistance heating boat, Alq. 200 mg of ₃ was placed and attached to a vacuum deposition apparatus.

Next, the pressure in the vacuum chamber is reduced to 4 × 10 ⁻⁴ Pa, and the heating boat containing α-NPD is energized and heated, and deposited on the transparent support substrate at a deposition rate of 0.1 nm / sec. Was provided. Further, the heating boat containing CBP and Comparative Compound 1 was heated by energization, and co-evaporated on the hole transport layer at a deposition rate of 0.2 nm / second and 0.012 nm / second, respectively, to provide a light emitting layer. It was. In addition, the substrate temperature at the time of vapor deposition was room temperature. Furthermore, the heating boat containing BCP was energized and heated, and deposited on the light emitting layer at a deposition rate of 0.1 nm / second to provide a 10 nm thick hole blocking layer. Further, 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, and an electron transport layer having a thickness of 40 nm is further provided. It was. 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 organic EL element 2-1 was produced.

  In the production of the organic EL device 2-1, except that BCP used as a hole blocking material was replaced with a compound shown in Table 2, and Comparative Compound 1 used as a phosphorescent compound was replaced with each compound shown in Table 2. Organic EL elements 2-2 to 2-15 were produced in the same manner as the organic EL element 2-1.

<< Evaluation of Organic EL Elements 2-1 to 2-15 >>
In the same manner as in Example 1, the luminance and the external extraction quantum efficiency of the organic EL elements 2-1 to 2-15 were evaluated. Furthermore, the lifetime was evaluated according to the measurement method shown below.

(lifespan)
When driving at a constant current of ^2.5 mA / cm ² , the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured, and this was calculated as the half-life time (τ 0.5). As an index of life. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) was used.

表２より明らかなように、比較例に比べて、本発明の有機ＥＬ素子は、輝度が高く、外部取り出し量子効率に優れ、かつ長寿命化が達成されていることが分かった。 The results obtained as described above are shown in Table 2. In addition, the measurement result of the brightness | luminance of Table 2, external extraction quantum efficiency, and lifetime was represented by the relative value when the organic EL element 2-1 is set to 100.

As is clear from Table 2, it was found that the organic EL device of the present invention has higher luminance, excellent external extraction quantum efficiency, and longer life than the comparative example.

《有機ＥＬ素子３−１〜３−８の評価》
下記に示す測定法に従って、保存性の評価を行った。 Example 3
<< Production of Organic EL Elements 3-1 to 3-8 >>
In the production of the organic EL device 1-1 described in Example 1, the host compound and the phosphorescent compound in the light emitting layer were changed to the compounds shown in Table 3, and BCP was changed to B-Alq. Organic EL elements 3-1 to 3-8 were produced.

<< Evaluation of Organic EL Elements 3-1 to 3-8 >>
The storage stability was evaluated according to the measurement method shown below.

(Storability)
After each organic EL element was stored at 85 ° C. for 24 hours, each brightness at a constant current drive of ^2.5 mA / cm ² before and after storage was measured, and each brightness ratio was determined according to the following formula, which was measured as a measure of storage stability. It was.

表３より明らかなように、比較例に比べて、本発明の有機ＥＬ素子は保存性に優れていることが分かった。 Storage stability (%) = luminance after storage ( ^2.5 mA / cm ² ) / luminance before storage ( ^2.5 mA / cm ² ) × 100
The results obtained as described above are shown in Table 3.

As is clear from Table 3, it was found that the organic EL device of the present invention was superior in storage stability compared to the comparative example.

Example 4
<< Production of Organic EL Elements 4-1 to 4-8 >>
In the production of the organic EL device 2-1 described in Example 2, the host compound (CBP) of the light emitting layer was changed to the exemplary compound 2-1, and further the hole blocking material of the hole blocking layer and the phosphorescence of the light emitting layer. Organic EL elements 4-1 to 4-8 were produced in the same manner except that the property compounds were changed as shown in Table 4.

<< Evaluation of Organic EL Elements 4-1 to 4-8 >>
The storage stability of the organic EL elements 4-1 to 4-8 was evaluated in the same manner as in Example 3, and the obtained results are shown in Table 4.

Example 5
The organic EL device 1-5 of the present invention produced in Example 1 and the phosphorescent compound of the organic EL device 1-5 of the present invention produced in Example 1 were prepared in the same manner except that they were replaced with Ir-1. A green light-emitting organic EL element and a red light-emitting organic EL element produced in the same manner except that the phosphorescent compound of the organic EL element 1-5 of the present invention is replaced with Ir-9 are juxtaposed on the same substrate, and are shown in FIG. The active matrix type full-color display device shown in the figure was produced. FIG. 2 shows only a schematic diagram of the display portion A of the produced full-color display device. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) on the same substrate. Each of the scanning lines 5 and the plurality of data lines 6 in the wiring portion is made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions (details). Is not shown). The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, full-color display is possible by appropriately juxtaposing the red, green, and blue pixels.

  By driving the full-color display device, a clear full-color moving image display was obtained.

Example 6
<Production of lighting device>
A non-light emitting surface of each of the blue, green, and red light emitting organic EL elements produced in Example 4 was covered with a glass case to obtain a lighting device. The illuminating device can be used as a thin illuminating device that emits white light having a high luminous efficiency and a long emission lifetime. FIG. 5 is a schematic view of the lighting device, and FIG. 6 is a cross-sectional view of the lighting device. The organic EL element 101 was covered with a glass cover 102. Reference numeral 105 denotes a cathode, 106 denotes an organic EL layer, and 107 denotes a glass substrate with a transparent electrode. The glass cover 102 is filled with nitrogen gas 108 and a water catching agent 109 is provided.

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

Claims (8)

Between a pair of electrodes, has a structure layer including a light emitting layer containing at least phosphorescent compound represented by the following general formula (1), at least one layer of said light-emitting layer is represented by the following general formula (2) An organic electroluminescent device characterized by containing a compound and emitting blue light . However, a combination of at least one phosphorescent compound selected from the following compounds 1 to 6 and the following compound B is excluded.

(In the formula, R ₁ represents an aromatic hydrocarbon group, an aromatic heterocyclic group, an alkoxy group, an amino group, or an alkyl group. Z represents a benzene ring. N1 represents an integer of 0 to 4. B ₁ to. the ring formed by B _5, the .M ₁ representing Louis imidazole ring having a respective alkyl group as a substituent, an aromatic hydrocarbon group or an aromatic heterocyclic group representing the iridium atom or a platinum atom .X ₁ And X ₂ represents a carbon atom, a nitrogen atom, or an oxygen atom, L ₁ represents an atomic group that forms a bidentate ligand together with X ₁ and X _2. m1 represents an integer of 1 to 3, and m2 represents (It represents an integer of 0 to 2, but m1 + m2 is 2 or 3.)

(In the formula, R ₃ and R ₄ represent an alkyl group or a phenyl group. N3 and n4 each represent 0 or 1. A ₁ and A ₂ represent a group represented by the following general formula (3).)

(In the formula, Z ₁ and Z ₂ represent a benzene ring or a pyridine ring, and Z ₃ represents a simple bond.)

The organic electroluminescent device according to claim 1, wherein the substituent of the ring formed by B _{1 to} B ₅ of the general formula (1) is an alkyl group, a phenyl group, or a thienyl group . The organic electroluminescence device according to claim 1 or 2, wherein M _{1 in the} general formula (1) is an iridium atom . 3. The organic electroluminescence device according to claim 1, wherein M _{1 in the} general formula (1) is a platinum atom. Wherein at least one layer of constituent layers is a hole blocking layer, any one of the claims 1-4, characterized that you containing the compound represented by the general formula the hole blocking layer (2) The organic electroluminescent element of the item. The organic electroluminescence element according to claim 1, which emits white light . A display device comprising the organic electroluminescence element according to claim 1 . It has an organic electroluminescent element as described in any one of Claims 1-6, The illuminating device characterized by the above-mentioned .

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