JP2013028757A - Organometallic complex and organic light emitting device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organometallic complex useful as a guest material of a blue phosphorescent light emitting device, and an organic light emitting device having high luminance efficiency.SOLUTION: The organometallic complex is represented by general formula [1]. In general formula [1], Rto Rare each independently selected from a hydrogen atom and an alkyl group, and a five-membered ring or a six-membered ring may be formed by the bonding of a sulfone group and an ether group.

Description

  The present invention relates to an organometallic complex and an organic light emitting device having the same.

  An organic light emitting element is an element having a pair of electrodes and an organic compound layer disposed between them. By injecting electrons and holes from the pair of electrodes, excitons of the luminescent organic compound in the organic compound layer are generated, and light is emitted when the excitons return to the ground state.

  In recent years, as an attempt to improve the light emission efficiency of an organic light emitting element, an organic light emitting element utilizing phosphorescence emission via triplet excitons has been actively developed. An organic light emitting device using phosphorescence emission is expected to improve luminous efficiency about 4 times that of fluorescent light emission.

  As such a phosphorescent compound, for example, Patent Document 1 discloses an iridium complex having a phenylpyridine ligand substituted with a trifluoromethyl group.

  Furthermore, Patent Document 2 discloses an iridium complex in which two types of fluorine-substituted phenylpyridine ligands and two monodentate ligands are coordinated.

  Regarding the technology for shortening the emission wavelength, the technology described above, that is, the technology for introducing an electron withdrawing group such as a cyano group or a sulfone group in addition to the introduction of a fluorine atom or a trifluoromethyl group to the phenylpyridine ligand is also known. It has been.

  Non-Patent Document 1 discloses an organometallic complex into which a sulfone group is introduced. The organometallic complex is an iridium complex in which phenylpyridine having a sulfone group substituted on a benzene ring and acetylacetone are coordinated.

Japanese translation of PCT publication No. 2004-503059 JP-A-2005-139185 Chemistry-A European Journal Vol. 15, No. 1, pages 136-148 (2009)

The iridium complex disclosed in Patent Document 1 has a slightly longer emission wavelength and does not become a blue light emitting material.
The iridium complex disclosed in Patent Document 2 has insufficient luminous efficiency.
An object of the present invention is to provide an organometallic complex that emits light in the blue region and has high luminous efficiency.

  Therefore, the present invention provides an organometallic complex represented by the following general formula [1].

In the general formula [1], R _{1 to} R ₇ are each independently selected from a hydrogen atom or an alkyl group.
The alkyl group is an alkyl group having 1 to 4 carbon atoms.
The sulfone group and the ether group in the general formula [1] may be bonded to form a 5-membered ring or a 6-membered ring.

  According to the present invention, an organometallic complex having high luminous efficiency can be provided. And the organic light emitting element with high luminous efficiency which has it can be provided.

It is a cross-sectional schematic diagram which shows an organic light emitting element and the switching element connected to this organic light emitting element.

  The present invention is an organometallic complex represented by the following general formula [1].

In the general formula [1], R _{1 to} R ₇ are each independently selected from a hydrogen atom or an alkyl group.
The alkyl group is an alkyl group having 1 to 4 carbon atoms.
The alkyl group having 1 to 4 carbon atoms is a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, or a tert-butyl group.

The sulfone group in the general formula [1] and an adjacent ether group may be bonded to form a 5-membered ring or a 6-membered ring.
That is, R1 and R2 are bonded to each other to form a 5-membered ring or a 6-membered ring. Forming a 5-membered ring means that R1 and R2 represent one carbon atom.

(About the nature of the organometallic complex related to the present invention)
In the organometallic complex according to the present invention, since the phenyl group in the molecular structure has a sulfone group and an alkoxy group, the emission wavelength is short and the emission efficiency is high.

  In the present embodiment, the blue region indicates light having a wavelength of 450 nm or more and 480 nm or less.

  Non-Patent Document 1 describes an organometallic complex using phenylpyridine substituted with a sulfone group and a diketone as a ligand.

Table 1 below shows the emission wavelengths (measured values) of the organometallic complexes described in Non-Patent Document 1.
What is shown as 4-SO2R is the organometallic complex described in Non-Patent Document 1, and the compound represented by a is a compound for comparison with the present invention.

  In the compound described in Non-Patent Document 1, the phenyl group in the molecular structure has a sulfone group, but does not have an alkoxy group.

  On the other hand, the organometallic complex represented by a has both a sulfone group and an alkoxy group.

  In Table 1, the emission wavelength of 4-SO2R is 498 nm.

  In the organometallic complex represented by a, the emission wavelength is shortened by providing a methoxy group at the 5-position adjacent to the sulfone group.

  The emission wavelength of the organometallic complex represented by a is 480 nm, which is 18 nm shorter than 4-SO2R.

  This is an effect obtained by providing a methoxy group having an electron-withdrawing property at the 5-position in addition to the electron-withdrawing effect of the 4-position sulfone group.

  The compound according to the present invention is an organometallic complex having three ligands that the organometallic complex represented by a has two.

  That is, since the compound according to the present invention has more sulfone groups and methoxy groups than the compound represented by a, the emission wavelength becomes a short wave.

  Since the organometallic complex according to the present invention has both the sulfone group and the alkoxy group in all of the three phenylpyridine ligands, blue light emission with high luminous efficiency can be obtained.

  Since the organometallic complex of the present invention has a high quantum yield of light emission in a solution, when the organometallic complex of the present invention is used as a constituent material of an organic light emitting device, the organic light emitting device is expected to have high luminous efficiency. it can.

  Therefore, when the organometallic complex according to the present invention is used as a light-emitting material, a blue organic light-emitting element with high color purity and high efficiency can be obtained.

(Examples of organic compounds related to the present invention)
Specific examples of the organometallic complex according to the present invention are shown below. However, the present invention is not limited to these.

(Description of synthesis route)
An example of a synthetic route for the compound according to the present invention will be described. The organometallic complex represented by the general formula [1] is disclosed in JP 2008-543971 A, Journal of Medicinal Chemistry, Vol. 24, No. 11, 1348-1353 (1981), Inorganic Chemistry, Vol. 40, Vol. 7, pages 1704 to 1711 (2001), Journal of Heterocyclic Chemistry, Vol. 19, No. 1, paragraphs 135 to 139 (1982) and the like. Specifically, it can be synthesized through the following steps.
(I) Synthesis of an organic compound serving as a ligand (ii) Synthesis of an organometallic complex.

  Here, the organic compound used as a ligand is compoundable as follows, for example.

The ligand can be obtained by treating compound A-1 with dimethyl sulfate under basic conditions. Compound A-3 can be obtained, for example, by reacting A-2 with bispinacol borane in the presence of a Pd catalyst. Compound A-5 can be obtained by reacting pinacol borane A-3 and A-4 in a mixed solvent of toluene, ethanol, and distilled water in the presence of sodium carbonate and Pd (PPh ₃ ) ₄ as a catalyst. .

  Various organic compounds can be synthesized by changing A-4.

  The organometallic complex according to the present invention can be synthesized by a synthesis method shown below using a ligand synthesized by the above synthesis route or the like.

  The iridium complex can be synthesized in three steps as follows.

(Description of the organic light emitting device according to the present embodiment)
Next, the organic light emitting device according to this embodiment will be described.

  The organic light-emitting device according to this embodiment is an organic light-emitting device having at least an anode and a cathode, which are a pair of electrodes facing each other, and an organic compound layer disposed therebetween.

  Among the organic compound layers, a layer having a phosphorescent material is a light emitting layer. In the organic light-emitting device according to the present invention, the organic compound layer contains an organometallic complex represented by the general formula [1].

  The organic compound layer included in the organic light emitting device according to this embodiment may be a single layer or a plurality of layers. The multiple layer is a layer appropriately selected from a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, an exciton diffusion blocking layer, and the like.

  Of course, it is possible to select a plurality from the above groups and use them in combination. For example, the organic light emitting element which has a pair of electrode, a positive hole injection layer, a positive hole transport layer, a light emitting layer, an electron carrying layer, and an electron injection layer is mentioned.

  Further, a plurality of light emitting layers may be provided, and each element may have a different emission color.

  A light-emitting element having a plurality of light-emitting layers may have a plurality of light-emitting layers between a pair of electrodes. For example, the structure which laminates | emits the light emitting layer which each emits red green blue between an anode and a cathode is mentioned.

  The configuration of the organic light emitting device according to this embodiment is not limited thereto. For example, an insulating layer is provided at the interface between the electrode and the organic compound layer, an adhesive layer or an interference layer is provided, and an electron transport layer or a hole transport layer is composed of two layers having different ionization potentials. it can.

  In this case, the element form may be a so-called top emission method in which light is extracted from the side opposite to the substrate, a so-called bottom emission method in which light is extracted from the substrate side, or a double-sided extraction configuration.

  In the organic light emitting device according to this embodiment, when there are a plurality of organic compound layers, any layer of the organic compound layer may have. For example, any of a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, and an electron transport layer. A light emitting layer is preferable.

  In the organic light-emitting device according to this embodiment, the light-emitting layer may be composed only of the organometallic complex according to the present invention, but preferably has a host material and a guest material. Furthermore, you may have assist material.

  Here, the host material is a compound having the largest weight ratio in the light emitting layer, and is a compound that exists as a matrix, and is a compound mainly responsible for carrier transport and excitation energy supply to the guest.

  The guest material is a compound having a weight ratio smaller than that of the host material in the light emitting layer and responsible for main light emission.

  The assist material has a weight ratio smaller than that of the host material in the light emitting layer and assists light emission of the guest material. The assist material is also called a second host material or host material 2.

  In addition, when using the organometallic complex which concerns on this embodiment as a guest material, it is preferable that the density | concentration of the guest material with respect to the whole light emitting layer is 0.1 to 30 mass%, and is 0.5 to 10 wt%. It is more preferable that

  The organic light-emitting device according to this embodiment can be used together with a conventionally known low molecular weight compound or high molecular weight compound, if necessary, in addition to the organometallic complex according to the present invention.

  Examples of these compounds are given below.

  The hole injecting material or hole transporting material is preferably a material having high hole mobility. Low molecular and high molecular weight materials having hole injection performance or hole transport performance include triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly (vinylcarbazole), poly (thiophene), In addition, although a conductive polymer is mentioned, of course, it is not limited to these.

  Host materials include organic compounds such as triarylamine derivatives, carbazole derivatives, phenylene derivatives, condensed ring aromatic compounds (eg, fluorene derivatives, benzene derivatives, triphenylene derivatives), organometallic complexes (eg, tris (8-quinolinolato) aluminum) Aluminum complexes, organic beryllium complexes, organic iridium complexes, organic platinum complexes, etc.) and poly (phenylene vinylene) derivatives, poly (fluorene) derivatives, poly (phenylene) derivatives, poly (thienylene vinylene) derivatives, poly (acetylene) derivatives, etc. However, the present invention is not limited to these. The host material is particularly preferably a compound having a triphenylene derivative.

  Here, the triphenylene derivative is a compound having a triphenylene skeleton in the molecular structure.

  The electron injecting material or the electron transporting material is selected in consideration of the balance with the hole mobility of the hole injecting material or the hole transporting material. Examples of materials having electron injection performance or electron transport performance include oxadiazole derivatives, oxazole derivatives, pyridine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, organoaluminum complexes, etc. It is not limited to. Further, an alkali metal such as lithium or cesium, an alkaline earth metal such as calcium, or a salt thereof may be doped.

  An anode material having a work function as large as possible is preferable. For example, simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, tungsten, or alloys thereof, tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide, etc. It is a metal oxide. Further, conductive polymers such as polyaniline, polypyrrole, and polythiophene may be used. These electrode materials may be used alone or in combination. Further, the anode may have a single layer structure or a multilayer structure.

  On the other hand, a cathode material having a small work function is preferable. Examples thereof include alkali metals such as lithium and cesium, alkaline earth metals such as calcium, and simple metals such as aluminum, titanium, manganese, silver, lead, and chromium. Or the alloy which combined these metal single-piece | units can also be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, etc. can be used. A metal oxide such as indium tin oxide (ITO) can also be used. These electrode materials may be used alone or in combination. Further, the cathode may have a single layer structure or a multilayer structure.

  In the organic light-emitting device according to this embodiment, the layer containing the organometallic complex according to this embodiment and the layer made of other organic compounds are formed by the method described below.

  In general, a layer is formed by a known coating method (for example, spin coating, dipping, casting method, LB method, ink jet method, etc.) after being dissolved in a vacuum deposition method, ionization deposition method, sputtering method, plasma, or an appropriate solvent. .

  Here, when a layer is formed by a vacuum deposition method, a solution coating method, or the like, crystallization or the like hardly occurs and the temporal stability is excellent. Moreover, when forming by the apply | coating method, a film | membrane can also be formed combining with a suitable binder resin.

  Examples of the binder resin include, but are not limited to, polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicon resin, urea resin, and the like. .

  Moreover, these binder resins may be used alone as a homopolymer or a copolymer, or may be used as a mixture of two or more. Furthermore, you may use together additives, such as a well-known plasticizer, antioxidant, and an ultraviolet absorber, as needed.

(Use of organic light emitting device according to this embodiment)
The organic light emitting element according to this embodiment can be used for a display device or a lighting device. In addition, it can be used for an exposure light source of an electrophotographic image forming apparatus, a backlight of a liquid crystal display device, and the like.

  The display device includes the organic light emitting element according to the present embodiment in a display unit. This display unit has a plurality of pixels. This pixel includes a TFT element as an example of the organic light emitting element according to the present embodiment and a switching element for controlling light emission luminance.

  Here, in the switching element, the anode or cathode of the organic light emitting element and the drain electrode or source electrode of the thin film transistor are connected.

  The display device can be used as an image display device such as a PC, a head mounted display, or a mobile phone. The displayed image may be a two-dimensional image or a three-dimensional image.

  The display device may include an input unit that inputs image information from an area CCD, a linear CCD, a memory card, or the like, and may be an image output device that outputs an input image to the display unit.

  The image output apparatus may be a digital camera having an image input unit as an image pickup device such as a CCD sensor and having an image pickup optical system.

  The display device may have an input function that allows input by touching the output image. For example, a touch panel function etc. are mentioned.

  The display device may be used for a display unit of a multifunction printer.

  The organic light emitting element according to this embodiment may be used in a lighting device. This illuminating device has the organic light emitting element which concerns on this embodiment, and the inverter circuit connected to the organic light emitting element.

  The color of the illumination light of the illumination device according to the present embodiment may be white, daylight white, or other colors.

In the case of white or neutral white, the lighting device may have a compound other than the compound according to the present embodiment.
That is, white or daylight white may be a color obtained by color mixing with a compound that emits an emission color different from the compound according to the present embodiment.

  Next, a display device having the organic light emitting element according to this embodiment will be described with reference to FIG.

  FIG. 1 is a schematic cross-sectional view showing an organic light emitting device according to this embodiment and a TFT device which is an example of a switching device connected to the organic light emitting device. In this figure, two sets of organic light emitting elements and TFT elements are shown. Details of the structure will be described below.

  The display device of FIG. 1 is provided with a substrate 1 made of glass or the like and a moisture-proof film 2 for protecting the TFT element or the organic compound layer on the substrate 1. Reference numeral 3 denotes a metal gate electrode. Reference numeral 4 denotes a gate insulating film, and reference numeral 5 denotes a semiconductor layer.

  The thin film transistor 8 includes a semiconductor layer 5, a drain electrode 6, and a source electrode 7. An insulating film 9 is provided on the thin film transistor 8, and an anode 11 and a source electrode 7 of the organic light emitting element are connected through a contact hole 10.

  The display device is not limited to this structure, and any one of the anode and the cathode and the thin film transistor source electrode or the drain electrode may be connected.

  Although the organic compound layer 12 is illustrated as a single layer in the drawing in a simplified manner, the organic compound layer 12 may actually be composed of multiple organic compound layers. A first protective layer 14 and a second protective layer 15 for suppressing deterioration of the organic light emitting element are provided on the cathode 13.

  In the display device according to this embodiment, the switching element is not particularly limited, and a transistor or an MIM element may be used. As the transistor, a thin film transistor using single crystal silicon, an amorphous silicon transistor element, or the like may be used. The thin film transistor is also called a TFT element.

  In the organic light emitting element, the light emission luminance is controlled by the switching element. By providing the organic light emitting elements in a plurality of planes, an image can be displayed with each light emission luminance.

  It is also possible to produce an active matrix driver on a Si substrate and provide an organic light emitting element thereon for control.

  This is selected depending on the definition. For example, in the case of a definition of about 1 inch and QVGA, it is preferable to provide an organic light emitting element on the Si substrate.

  By driving the display device using the organic light emitting element according to the present embodiment, stable long-time display with good image quality becomes possible.

Example 1
[Synthesis of Exemplary Compound (2)]

(1) Synthesis of Compound A-2 Reagents and solvents shown below were charged into the reaction vessel.
Sodium sulfite: 4.14 g (32.8 mmol)
Sodium bicarbonate: 2.90 g (34.5 mmol)
Water: 18ml
The suspension was stirred at 80 ° C. and A-1 (sulfonyl chloride, 5.0 g, 17.5 mmol) was added in portions over 20 minutes. After stirring at 80 ° C. for 6 hours, the mixture was stirred at room temperature for 16 hours. The precipitated solid was collected by filtration and dried under high vacuum. The dried solid (4.8 g) was added to a mixture of sodium bicarbonate (2.90 g, 33.3 mmol), dimethyl sulfate (2.5 ml, 26.3 mmol) and water (6.5 ml). The suspension was heated at 120 ° C. for 8 hours, then cooled to room temperature, transferred to a separatory funnel, water was added, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over sodium sulfate. The solvent was concentrated under reduced pressure to obtain the target product A-2 (3.21 g, 69%).

(2) Synthesis of Compound A-3 Reagents and solvents shown below were charged into the reaction vessel.
Compound A-2: 2.50 g (9.43 mmol)
Bispinacol diborane: 3.59 g (14.1 mmol)
PdCl2 (dppf) .CH2Cl2: 385 mg (0.47 mmol)
Potassium acetate: 2.78 g (28.3 mmol)
Dioxane: 40ml
The suspension was stirred at 90 ° C. for 8 hours under a nitrogen stream, and then cooled to room temperature. Inorganics were removed by celite filtration and washed with ethyl acetate. After the filtrate was concentrated under reduced pressure, the residue was purified by silica gel column chromatography (mobile phase; heptane: ethyl acetate = 2: 1) to obtain 1.94 g (yield 66%) of A-3.

(3) Synthesis of Compound A-5 Reagents and solvents shown below were charged into the reaction vessel.
Compound A-3: 1.60 g (5.13 mmol)
Compound A-4: 654 mg (5.13 mmol)
Toluene: 30ml
Ethanol: 10ml
10% by weight cesium carbonate aqueous solution: 20 ml
Tetrakistriphenylphosphine palladium (0) (296 mg, 0.26 mmol) was added to the reaction solution, and the mixture was heated to 90 ° C. and stirred for 7 hours. After cooling, water was added to perform liquid separation extraction. After the organic layer was concentrated under reduced pressure, the residue was purified by silica gel column chromatography (mobile phase; heptane: toluene = 20: 1) to obtain 1.20 g (yield 85%) of A-5.

(4) Synthesis of Compound A-6 Reagents and solvents shown below were charged into the reaction vessel.
Iridium (III) trihydrate: (850 mg, 2.40 mmol)
Compound A-5: 1.50 g (5.41 mmol)
Ethoxyethanol: 20ml
Water: 10ml
The reaction solution was stirred at room temperature for 10 minutes under a nitrogen stream, then heated to 90 ° C. and stirred for 6 hours. The reaction solution was cooled to room temperature, water was added, and the deposited precipitate was collected by filtration and washed with water. This solid was vacuum dried at 100 ° C. to obtain 870 mg (47%) of A-6 as a pale yellow powder.

(5) Synthesis of Compound A-7 Reagents and solvents shown below were charged into the reaction vessel.
Compound A-6: 870 mg (1.16 mmol)
Acetylacetone: 0.21 ml (2.02 mmol)
Sodium carbonate: 800 mg (7.54 mmol)
Ethoxyethanol: 25ml
The reaction solution was stirred at room temperature for 20 minutes under a nitrogen stream, then heated to 100 ° C. and stirred for 7 hours. The reaction solution was cooled to room temperature, water was added, and the deposited precipitate was collected by filtration and washed with water. This solid was vacuum-dried at 100 ° C. to obtain 640 mg (65%) of A-7 as a yellow powder.

(6) Synthesis of Exemplified Compound (2) Reagents and solvents shown below were charged into the reaction vessel.
Compound A-7: 640 mg (0.76 mmol)
Compound A-5: 527 mg (1.90 mmol)
Glysenol: 15ml
The reaction solution was heated to 190 ° C. under a nitrogen stream and stirred for 6 hours. The reaction solution was cooled to room temperature, water was added, and the deposited precipitate was collected by filtration and washed with water. This solid was vacuum-dried at 100 ° C. to obtain 715 mg (93%) of Exemplary Compound (2) as a yellow powder.

  By mass spectrometry, 1021 which was M + of the exemplary compound (2) was confirmed.

Moreover, the structure of exemplary compound (2) was confirmed by < ¹ > H-NMR measurement.
¹ H-NMR (CDCl ₃ , 400 MHz) σ (ppm): 2.47 (s, 9H), 3.13 (s, 9H), 3.57 (s, 9H), 6.45 (s, 3H) 6.80 (d, J = 5.0 Hz, 3H), 7.31 (d, J = 5.0 Hz, 3H), 7.75 (s, 3H), 8.17 (s, 3H)
When the emission spectrum in the toluene dilute solution was measured about exemplary compound (2), the light emission maximum wavelength was 467 nm.

The measurement of _{T 1} is a toluene solution ^{(1 × 10 -4 mol / L} ), a phosphorescent component measured at an excitation wavelength of 350 nm, exhibited a wavelength of rise of the spectrum. The apparatus used was a Hitachi spectrophotometer F-4500.

On the other hand, for the exemplified compound (2), the quantum yield was calculated from the absorbance and emission area of the compound itself and found to be 0.71. The absorbance was measured by JASCO, UV-visible spectrophotometer V-5.
It was evaluated from an absorption spectrum in a toluene solution (1 × 10 ⁻⁴ mol / L) measured using 60.

(Example 2)
[Synthesis of Exemplary Compound (10)]
Exemplified compound (10) was synthesized in the same manner as in Example 1, except that compound A-3 was changed to the following compound A-8.

  By mass spectrometry, 973 which was M + of the exemplary compound (10) was confirmed.

Moreover, the structure of exemplary compound (10) was confirmed by < ¹ > H-NMR measurement.
¹ H-NMR (CDCl ₃ , 400 MHz) σ (ppm): 2.48 (s, 9H), 6.45 (s, 3H), 6.83 (d, J = 5.0 Hz, 3H), 7. 27 (d, J = 5.0 Hz, 3H), 7.70 (s, 3H), 7.89 (s, 3H)
Moreover, when the emission spectrum in the toluene dilute solution was measured about Example compound (10) like Example 1, when the light emission maximum wavelength was 468 nm.

(Example 3)
[Synthesis of Exemplified Compound (18)]
Exemplified compound (18) was synthesized in the same manner as in Example 1, except that compound A-3 was changed to the following compound A-9.

  By mass spectrometry, 1057 which was M + of the exemplary compound (18) was confirmed.

  Moreover, when the emission spectrum in the toluene dilute solution was measured about Example compound (18) like Example 1, the emission maximum wavelength was 469 nm.

Example 4
In this example, an organic light emitting device having a structure in which an anode / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / cathode were sequentially provided on a substrate was produced by the following method. .

  A transparent conductive support substrate (ITO substrate) obtained by depositing ITO as a positive electrode with a film thickness of 120 nm on a glass substrate was used.

On this ITO substrate, the following organic compound layer and electrode layer were continuously formed by vacuum deposition by resistance heating in a vacuum chamber of 10 ⁻⁵ Pa. At this time, the opposing electrode area was 3 mm ² .
Hole transport layer (40 nm) A-10
Electron blocking layer (10 nm) A-11
Light emitting layer (30 nm) Host material 1: A-12, Guest material: Exemplary compound (2) (10 wt%)
Hole blocking layer (10 nm) A-13
Electron transport layer (30 nm) A-14
Metal electrode layer 1 (0.5 nm) LiF
Metal electrode layer 2 (100 nm) Al

  Next, the organic light emitting device was covered with a protective glass plate in a dry air atmosphere and sealed with an acrylic resin adhesive so that the device did not deteriorate due to moisture adsorption. An organic light emitting device was obtained as described above.

With respect to the obtained organic light emitting device, the applied voltage at an emission luminance of 500 cd / m ² was measured with the ITO electrode as the positive electrode and the Al electrode as the negative electrode, and it was 4.0 V. The light emission efficiency was 12.2 lm / W, and blue light emission was observed.

(Example 5)
An organic light emitting device was produced in the same manner as in Example 4 except that the guest material was changed to the exemplified compound (10).

With respect to the obtained organic light emitting device, the applied voltage at an emission luminance of 500 cd / m ² was measured with the ITO electrode as the positive electrode and the Al electrode as the negative electrode, and it was 4.1 V. The light emission efficiency was 12.0 lm / W, and blue light emission was observed.

  As described above, the organometallic complex according to the present invention emits light in the blue region and has high luminous efficiency. Therefore, when used in an organic light emitting device, an organic light emitting device with high luminous efficiency can be obtained.

8 TFT element 11 Anode 12 Organic compound layer 13 Cathode

Claims (6)

An organometallic complex represented by the following general formula [1].

In the general formula [1], R _{1 to} R ₇ are each independently selected from a hydrogen atom or an alkyl group.
The alkyl group is an alkyl group having 1 to 4 carbon atoms.
The sulfone group and the ether group in the general formula [1] may be bonded to form a 5-membered ring or a 6-membered ring.   An organic light emitting device comprising: a pair of electrodes; and an organic compound layer disposed between the pair of electrodes, wherein the organic compound layer includes the organometallic complex according to claim 1. The organic compound layer has a light emitting layer, the light emitting layer has a host material and a guest material,
The organic light-emitting element according to claim 2, wherein the guest material is the organometallic complex.   A display device comprising a plurality of pixels, wherein the pixels include the organic light-emitting element according to claim 2 and a switching element connected to the organic light-emitting element.   It has an input part for inputting image information, and a display part for outputting an image, The display part has a plurality of pixels, and the pixels are the organic light emitting element according to claim 2 or 3, An image output apparatus comprising: a switching element connected to the organic light emitting element.   An illuminating device comprising: the organic light emitting device according to claim 2; and an inverter circuit connected to the organic light emitting device.