JP5355437B2 - Organic electroluminescence device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element concurrently having high color purity and high efficiency. <P>SOLUTION: The organic electroluminescent element is constituted of a positive electrode (transparent electrode 14) and a negative electrode (metal electrode 11), and an organic compound layer, having at least a light emitting layer 12 interposed between the positive electrode and the negative electrode. The light-emitting layer 12 contains a metal complex compound that includes one of the coupling forms (a) to (d): (a) Ir-SO, (b) Ir-SO<SB>2</SB>, (c) Pt-SO, and (d) Pt-SO<SB>2</SB>. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an organic electroluminescent device.

  An organic electroluminescent element is an electronic element having two layers of upper and lower electrodes on a transparent substrate, and a laminate in which one or a plurality of organic compound layers including a light emitting layer are sandwiched between these electrodes. . Organic electroluminescent devices are attracting attention as one of the next-generation full-color display technologies because of their high-speed response, high efficiency, and flexibility, and technical development of materials and devices is being vigorously conducted.

In recent years, organic electroluminescence devices of a type using phosphorescence emission via triplet excitons have been actively developed for the purpose of increasing the efficiency of the devices. For example, the organic electroluminescent element currently disclosed by the nonpatent literature 1 and 2 is mentioned. The organic electroluminescent elements disclosed in Non-Patent Documents 1 and 2 are elements having four organic compound layers. Specifically, from the anode side, a hole transport layer, a light emitting layer, an exciton diffusion preventing layer, It has a laminate composed of an electron transport layer. However, in the light emitting layer constituting the organic electroluminescent element disclosed in Non-Patent Documents 1 and 2, the material used as the phosphorescent light emitting material is a green phosphorescent light emitting material such as Ir (ppy) _3. It was limited.

  By the way, the target of technological development in materials and elements using phosphorescence emission has recently been shifted to blue phosphorescence light emitting elements having both high color purity and high efficiency. Bis [3,5-difluoro-2- (2-pyridinyl-.N) phenyl-.C] (2,4-pentanediato-.O, .O ')-Iridium (III) disclosed in Non-Patent Document 3 ) (Common name: FIrpic, Registry Number: 710307-36-1) is a typical example of a phosphorescent material that emits blue light. However, since the emission peak wavelength due to the 0-0 transition of this material is 470 nm, there is a problem in color purity.

  Patent Document 1 discloses a blue phosphorescent light emitting device using a metal complex having a coordinate bond or a covalent bond between a metal (iridium atom or platinum atom) and a phosphorus atom. Here, Patent Document 1 discloses a metal complex in which a phosphorus atom and a metal contained in a ligand are coordinated at a ratio of 1: 1 or 2: 1. Here, the metal complex in which the phosphorus atom and the metal contained in the ligand are coordinate-bonded at a ratio of 1: 1 requires at least one ligand that is covalently bonded in monodentate such as a halogen atom. However, an organic electroluminescence device using a metal complex containing a halogen atom (for example, an Ir complex) has a problem that the luminous efficiency is low. Moreover, in the metal complex in which the phosphorus atom and metal contained in the ligand are coordinated at a ratio of 2: 1, there is a problem that the Ir complex is ionized.

  As mentioned above, organic electroluminescent devices are one of the next generation full-color display technologies, but there are still no blue phosphorescent materials and devices that can be used for them, which have both high color purity and high efficiency. is there.

Japanese Patent No. 4067286

Improve energy transfer in electrophoretic device (DF O'Brien et al., Applied Physics Letters Vol. 74, No. 3, p422 (1999)) Very high-efficiency green organic light-emitting devices basd on electrophoresis (MA Baldo et al., Applied Physics Letters Vol. 75, No. 1, 4). Endogenous energy transfer: A machinery for generating highly efficient-energy phosphorescent emission in organic materials, et al., 79. V. H. Thompson, M. A. Thompson, et al. G. Wilkinson et al., Comprehensive Coordination Chemistry (Pergamon Press, 1987) H. Yersin, “Photochemistry and Photophysics of Coordination Compounds” (Springer-Verlag, 1987) Akio Yamamoto, “Organic Metal Chemistry: Fundamentals and Applications” (Ikuwabosha, 1982) M.M. Maestri et al., Advances in photochemistry, Vol. 17, 1, John Wiley & Sons, 1992 Tuning iridium (III) phenylpyridine complexes in the “almost blue” region ”Chemical Communications (Cambridge, United Kingdom) (2004), (15), 1774-1775.

  An object of the present invention is to provide an organic electroluminescent device having both high color purity and high efficiency.

The organic electroluminescent device of the present invention comprises an anode, a cathode,
An organic compound layer sandwiched between the anode and the cathode and having at least a light-emitting layer,
The light emitting layer is bonded to any of the following bond types (a) to Ir-SO:
(B) Ir-SO ₂
(C) Pt-SO
(D) Pt—SO ₂
The metal complex compound containing is contained, It is characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the organic electroluminescent element which has high color purity and high efficiency can be provided.

It is sectional drawing which shows the example of embodiment in the organic electroluminescent element of this invention. It is a figure which shows typically the structural example of the display apparatus provided with the organic electroluminescent element and drive means of this invention which are one form of a display apparatus. FIG. 3 is a circuit diagram showing a circuit constituting one pixel arranged in the display device of FIG. 2. It is the schematic diagram which showed an example of the cross-section of the TFT substrate used with the display apparatus of FIG.

  Hereinafter, the organic light emitting field device of the present invention will be described in detail.

The organic electroluminescent device of the present invention comprises an anode, a cathode,
The organic compound layer is sandwiched between the anode and the cathode and has at least a light emitting layer.

  Hereinafter, the organic light emitting field device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a cross-sectional view showing an example of an embodiment of the organic electroluminescent element of the present invention. Here, (a) shows the first embodiment, (b) shows the second embodiment, and (c) shows the third embodiment.

  In the organic electroluminescent device 1a of FIG. 1A, a laminate composed of a metal electrode 11, a light emitting layer 12, a hole transport layer 13, and a transparent electrode 14 in this order is provided on a transparent substrate 15. ing.

  In the organic electroluminescent element 1b of FIG. 1B, an electron transport layer 16 is provided between the metal electrode 11 and the light emitting layer 12 in the organic electroluminescent element 1a of FIG. In the organic electroluminescent element 1b of FIG. 1B, a layer having a light emitting function and a layer having a function of either electron or hole transport are separated. With this configuration, since carrier blocking can be performed more effectively, the light emission efficiency can be further improved.

  In the organic electroluminescent element 1c of FIG. 1C, an exciton diffusion preventing layer 17 is provided between the electron transport layer 16 and the light emitting layer 12 in the organic electroluminescent element 1b of FIG. In the organic electroluminescent device 1c of FIG. 1C, by providing the exciton diffusion preventing layer 17, excitons can be efficiently confined in the light emitting layer 12, so that the luminous efficiency can be further improved. Is possible.

  The organic electroluminescent element of the present invention is not limited to the above embodiment. For example, an electron blocking layer or an acid diffusion preventing layer may be provided between the hole transport layer and the light emitting layer. These have functions such as suppressing leakage of electrons from the light emitting layer and blocking the ion component (acid component) from the hole transport layer side so as not to reach the light emitting layer.

  In general, an organic electroluminescent element has a transparent electrode 14 having a film thickness of 50 nm to 200 nm on a transparent substrate 15, a layer made of a plurality of organic compounds, and a metal electrode formed on the layer made of the organic compounds. 11 are sequentially stacked.

  The organic electroluminescent element 1a shown in FIG. 1A exhibits electrical rectification. That is, when an electric field is applied so that the metal electrode 11 serves as a cathode and the transparent electrode 14 serves as an anode, electrons are injected from the metal electrode 11 and holes are injected from the transparent electrode 15 toward the light emitting layer 12. The injected holes and electrons reach the light emitting layer 12 and recombine in the light emitting molecules in the light emitting layer 12. At this time, excitons of the luminescent molecule are generated, and light is emitted when the excitons return to the ground state. At this time, since the hole transport layer 13 plays a role of blocking electrons, the recombination efficiency at the interface between the light emitting layer 12 and the hole transport layer 13 is increased. For this reason, luminous efficiency improves compared with the organic electroluminescent element in which the layer provided between electrodes is only a light emitting layer.

In the organic electroluminescent element of the present invention, the light emitting layer 12 includes a metal complex compound that is a phosphorescent material and includes any one of the following bond types (a) to (d).
(A) Ir-SO
(B) Ir-SO ₂
(C) Pt-SO
(D) Pt—SO ₂

That is, in the organic electroluminescent element of the present invention, the light emitting layer 12 includes Ir (iridium atom) or Pt (platinum atom) as a central metal, and a ligand having sulfide (SO) or sulfone (SO ₂ ). The metal complex compound which consists of is contained.

However, in the metal complex compound included in the light emitting layer 12 as a phosphorescent material, the ligand included in the metal complex compound is limited to a ligand having sulfide (SO) or sulfone (SO ₂ ). It is not something.

In addition to ligands having sulfide (SO) or sulfone (SO ₂ ), for example, known ligands described in Non-Patent Documents 4 to 6, etc., ligands shown below (conformation number) May be optionally included).

  Of the above-mentioned known ligands, nitrogen-containing heterocyclic ligands (eg, phenylpyridine, benzoquinoline, quinolinol, bipyridyl, phenanthroline, etc.), diketone ligands (eg, acetylacetone, etc.), carboxylic acids A ligand (for example, an acetic acid ligand or the like); More preferably, it is a nitrogen-containing heterocyclic ligand.

  Preferred examples of the metal complex compound contained in the light emitting layer 12 will be described below. As the metal complex compound contained in the light emitting layer 12, a compound represented by the following general formula (1) is preferable.

  In the formulas (1a) and (1b), M represents an iridium atom or a platinum atom.

  In the formulas (1a) and (1b), n is 1 or 2.

In formulas (1a) and (1b), Q _{1 to} Q ₁₂ represent a nitrogen atom or CR ₁ . When Q _{1 to} Q ₁₂ are CR ₁ , R ₁ represents a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group.

As the alkyl group represented by R ₁ , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, hexyl group, cyclopropyl group, cyclopentyl Group, cyclohexyl group and the like.

Examples of the alkenyl group represented by R ₁ include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group.

Examples of the aryl group represented by R ₁ include a phenyl group, a biphenyl group, and a terphenyl group.

Specific examples of the substituent that the alkyl group, alkenyl group, and aryl group may further include include the following substituents. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

  In the formulas (1a) and (1b), m is an integer of 0 to 2, and l is an integer of 1 to 3. However, m + 1 is 2 or 3.

In the formula (1a), X ₁ is a nitrogen atom or a phosphorus atom. The nitrogen atom and the phosphorus atom may have a substituent. Specific examples include the substituents shown below. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

In the formula (1a), X ₁ is a nitrogen atom or a phosphorus atom. The nitrogen atom and phosphorus atom may have the above substituent. In the formula (1b), X ₂ is an oxygen atom or a sulfur atom.

  Another preferred example of the metal complex compound contained in the light emitting layer 12 is a compound represented by the following general formula (2).

  In formula (2), M represents an iridium atom or a platinum atom.

  In the formula (2), n is 1 or 2.

In the formula (2), Y represents an oxygen atom or C (R ₂ ) ₂ . When Y is C (R ₂ ) ₂ , R ₂ represents a hydrogen atom, a fluorine atom, a substituent or an unsubstituted alkyl group, a substituent or an unsubstituted alkenyl group, a substituent or an unsubstituted aryl group.

As the alkyl group represented by R ₂ , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, hexyl group, cyclopropyl group, cyclopentyl Group, cyclohexyl group and the like.

Examples of the alkenyl group represented by R ₂ include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group.

Examples of the aryl group represented by R ₂ include a phenyl group, a biphenyl group, and a terphenyl group.

Specific examples of the substituent that the alkyl group, alkenyl group, and aryl group may further include include the following substituents. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

In the formula (2), Q _{13 to} Q ₂₄ represent a nitrogen atom or CR ₃ . When Q _{13 to} Q ₂₄ are CR ₃ , R ₃ represents a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group.

As the alkyl group represented by R ₃ , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, hexyl group, cyclopropyl group, cyclopentyl Group, cyclohexyl group and the like.

Examples of the alkenyl group represented by R ₃ include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group.

Examples of the aryl group represented by R ₃ include a phenyl group, a biphenyl group, and a terphenyl group.

Specific examples of the substituent that the alkyl group, alkenyl group, and aryl group may further include include the following substituents. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

  In the formula (2), m is an integer from 0 to 2, and l is an integer from 1 to 3. However, m + 1 is 2 or 3.

  Other preferred examples of the metal complex compound contained in the light emitting layer 12 include compounds represented by the following general formula (3).

  In the formulas (3a) and (3b), M represents an iridium atom or a platinum atom.

  In the formulas (3a) and (3b), n is 1 or 2.

  In formulas (3a) and (3b), Z is a nitrogen atom or a carbon atom.

In formulas (3a) and (3b), Q _{25 to} Q ₃₇ represent a nitrogen atom or CR ₄ . When Q _{252 to} Q ₃₇ are CR ₄ , R ₄ represents a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group.

As the alkyl group represented by R ₄ , methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, secondary butyl group, tertiary butyl group, pentyl group, hexyl group, cyclopropyl group, cyclopentyl Group, cyclohexyl group and the like.

Examples of the alkenyl group represented by R ₄ include a vinyl group, an allyl group, a 2-butenyl group, and a 3-pentenyl group.

Examples of the aryl group represented by R ₄ include a phenyl group, a biphenyl group, and a terphenyl group.

Specific examples of the substituent that the alkyl group, alkenyl group, and aryl group may further include include the following substituents. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

  In Formula (3a) and Formula (3b), m is an integer from 0 to 2, and l is an integer from 1 to 3. However, m + 1 is 2 or 3.

In Formula (3a), it is a nitrogen atom or a phosphorus atom. The nitrogen atom and the phosphorus atom may have a substituent. Specific examples include the substituents shown below. However, the present invention is not limited to this.
(A) an alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms. For example, methyl Group, t-butyl group, hexyl group, cyclohexyl group, etc.).
(B) an alkenyl group (preferably an alkenyl group having 2 to 30 carbon atoms, more preferably an alkenyl group having 2 to 12 carbon atoms, and still more preferably an alkenyl group having 2 to 6 carbon atoms. For example, a propenyl group Etc.)
(C) Alkynyl group (preferably an alkynyl group having 2 to 30 carbon atoms, more preferably an alkynyl group having 2 to 12 carbon atoms, and still more preferably an alkynyl group having 2 to 6 carbon atoms. For example, an ethynyl group Etc.)
(D) Aryl group (preferably an aryl group having 6 to 40 carbon atoms, more preferably an aryl group having 6 to 20 carbon atoms, and still more preferably an aryl group having 6 to 12 carbon atoms. For example, a phenyl group , Tolyl group, naphthyl group, anthracenyl group, etc.)
(E) Heteroaryl group (specifically, a heteroaryl group containing an oxygen atom, sulfur atom or nitrogen atom, preferably a heteroaryl group having 1 to 40 carbon atoms, more preferably 2 to 20 carbon atoms) And more preferably a heteroaryl group having 3 to 12 carbon atoms, such as a pyridyl group, a thienyl group, a carbazolyl group, a piperidyl group, and a morpholino group.
(F) an alkoxy group (preferably an alkoxy group having 1 to 30 carbon atoms, more preferably an alkoxy group having 1 to 12 carbon atoms, and still more preferably an alkoxy group having 1 to 6 carbon atoms. For example, a methoxy group And isopropoxy group.)
(G) Aryloxy group (preferably an aryloxy group having 6 to 40 carbon atoms, more preferably an aryloxy group having 6 to 20 carbon atoms, and still more preferably an aryloxy group having 6 to 12 carbon atoms. For example, a phenoxy group, a naphthoxy group, a pyrenyloxy group, etc. are mentioned.)
(H) A silyl group (preferably a silyl group having 1 to 30 carbon atoms, more preferably a silyl group having 3 to 20 carbon atoms, and still more preferably a silyl group having 3 to 12 carbon atoms. For example, a trimethylsilyl group, and t-butyldimethylsilyl group, triphenylsilyl group, etc.).
(I) Halogen atom (fluorine, chlorine, bromine, iodine, etc.)
(J) Deuterium

In the formula (3a), X ₁ is a nitrogen atom or a phosphorus atom. The nitrogen atom and phosphorus atom may have the above substituent. In the formula (3b), X ₂ is an oxygen atom or a sulfur atom.

  In the present invention, the metal complex compound contained in the light emitting layer 12 preferably has an emission peak wavelength due to 0-0 transition of 400 nm or more and 480 nm or less. When the wavelength is longer than 480 nm, a green emission color is generated, and when the wavelength is shorter than 400 nm, the visibility (referred to as spectral luminous efficacy) is deteriorated. The emission peak wavelength is more preferably 420 nm or more and 460 nm or less.

  In the phosphorescent light emitting device of the present invention, it is preferable that the x and y values of the CIE chromaticity value of light emission are small from the viewpoint of the blue color purity of the light emission color. Specifically, the x value of the CIE chromaticity value of light emission is preferably 0.25 or less, and more preferably 0.20 or less. An x value larger than 0.25 is not preferable because a pale color is obtained. In addition, the y value of the CIE chromaticity value of light emission is preferably 0.35 or less, and more preferably 0.30 or less. If the y value is larger than 0.35, the green color is not preferable.

  By the way, the bond between iridium or platinum and the sulfur atom contained in sulfide or sulfone greatly contributes to shortening the emission color of phosphorescence emitted from the metal complex compound. Below, the mechanism which can be assumed is demonstrated.

  First, the ligand having sulfide or sulfone increases the triplet energy level of the ligand due to the wide gap resulting from the increased LUMO level of the ligand itself. As a result, it is considered that the wave length of the metal complex compound indirectly occurs.

In addition, due to the strong electron withdrawing effect of sulfide or sulfone contained in the ligand, the HOMO level of the central metal is lowered, and the energy gap with the LUMO of the ligand is increased. As a result, it is considered that the phosphorescence emission has a shorter wavelength. Note that the electron-withdrawing effect is one that Hammett effects, [delta] _p value as an index of Hammette effect is a substituent constant determined from the electronic effect of substituents on the hydrolysis of ethyl benzoate. The larger this value, the greater the electron withdrawing effect. Representative examples are listed in the table below.

  As shown in the above table, the electron-withdrawing effect of the methanesulfonyl group (mesyl group) having a sulfone is very large.

  In addition to this, it is considered that the ligand field strength of the ligand having sulfide or sulfone is large and the wavelength is shortened by the ligand field effect (see Non-Patent Document 7).

  Hereinafter, although the specific example of the phosphorescence-emitting material of this invention is shown, this invention is not limited to this.

  Next, the constituent members of each layer constituting the organic electroluminescent element of the present invention will be described.

  As the transparent substrate 15 used in the organic electroluminescent element of the present invention, a substrate made of a light transmissive material such as glass can be used.

  As a constituent material of the transparent electrode 14, a material having a large work function, for example, ITO or the like is used. When a material having a large work function is used as the material of the transparent electrode 14, hole injection from the transparent electrode 14 to the hole transport layer 13 is facilitated.

  Specific examples of the hole transport material that is a constituent material of the hole transport layer 13 include triarylamine derivatives, phenylenediamine derivatives, triazole derivatives, oxadiazole derivatives, carbazole derivatives, poly (vinylcarbazole), and poly (silylene). And poly (thiophene).

  The light emitting layer 12 includes the phosphorescent light emitting material described above, but other light emitting materials may be mixed as a host. It is important that the host is a compound having a triplet energy level higher than that of the phosphorescent material contained in the light emitting layer 12 as a guest (dopant). When the triplet energy level of the host is smaller than the triplet energy level of the phosphorescent material, the energy transfer from the host to the phosphorescent material is inhibited (the energy transfer from the phosphorescent material to the host is inhibited). It may occur) and is not preferable.

  As a host included in the light emitting layer 12, for example, a terphenyl derivative, a fluorene derivative, a triphenylene derivative, a silane derivative such as tetraphenylsilane, a polymer compound such as polyphenylene, or the like may be included in the light emitting layer 12 as a host. From the viewpoint of the triplet energy level described above, a compound having a triplet energy level higher than that of the phosphorescent material, specifically, a terphenyl derivative, a triphenylene derivative, or a carbazole derivative is more preferable.

  Specific examples of the electron transporting material that is a constituent material of the electron transport layer 16 include compounds such as a xadiazole derivative, a thiadiazole derivative, a pyrazine derivative, a triazole derivative, a triazine derivative, a quinoxaline derivative, and a phenanthroline derivative.

  As a constituent material of the metal electrode 11, a metal material having a small work function such as a simple metal such as aluminum or magnesium or an alloy combining these simple metals is used. When a material having a small work function is used as the constituent material of the metal electrode 11, electron injection from the metal electrode 11 to the organic compound layer, for example, the electron transport layer 16 is facilitated.

  The manufacturing method of the organic electroluminescent element of the present invention is not particularly limited, but a vapor deposition method, a sputtering method, a CVD method, a thermal transfer method or a coating method (spin coating method, ink jet method, printing method [offset, gravure, convex, concave, Screen printing, etc.], spray method, liquid development method applying electrophotography) and the like. In particular, the light emitting layer containing a phosphorescent light emitting material is preferably formed by a coating method.

  The organic electroluminescence device of the present invention can be applied to products that require energy saving and high luminance. Application examples include a display device, a light source of a printer, an illumination device, a backlight of a liquid crystal display device, and the like.

  Examples of the display device include a flat panel display that is energy-saving, highly visible, and lightweight.

  Moreover, as a light source of a printer, the laser light source part of the laser beam printer currently widely used can be replaced with the organic electroluminescent element of the present invention, for example. As a replacement method, for example, a method of arranging an organic electroluminescent element that can be independently addressed on the array can be mentioned. Even when the laser light source portion is replaced with the organic electroluminescent element of the present invention, image formation is not different from conventional methods by performing desired exposure on the photosensitive drum. Here, by using the organic electroluminescent element of the present invention, the volume of the apparatus can be greatly reduced.

  With respect to the illumination device and the backlight, an energy saving effect can be expected by using the organic electroluminescent element of the present invention.

  Next, a display device using the organic electroluminescent element of the present invention will be described. Hereinafter, the display device of the present invention will be described in detail with reference to the drawings, taking an active matrix system as an example.

  FIG. 2 is a diagram schematically illustrating a configuration example of a display device including the organic electroluminescence element of the present invention and a driving unit, which is an embodiment of the display device. 2 includes a scanning signal driver 21, an information signal driver 22, and a current supply source 23, which are connected to a gate selection line G, an information signal line I, and a current supply line C, respectively. A pixel circuit 44 is disposed at the intersection of the gate selection line G and the information signal line I. The scanning signal driver 41 sequentially selects the gate selection lines G1, G2, G3... Gn, and in synchronization with this, the image signal from the information signal driver 42 is one of the information signal lines I1, I2, I3. The voltage is applied to the pixel circuit 24 via these.

Next, the operation of the pixel will be described. FIG. 3 is a circuit diagram showing a circuit constituting one pixel arranged in the display device of FIG. In the pixel circuit 30 of FIG. 3, when a selection signal is applied to the gate selection line Gi, the first thin film transistor (TFT1) 31 is turned on, the image signal Ii is supplied to the capacitor (C _add ) 32, The gate voltage of the second thin film transistor (TFT2) 33 is determined. A current is supplied to the organic electroluminescent element 34 from the current supply line Ci according to the gate voltage of the second thin film transistor (TFT2) (33). Here, the gate potential of the second thin film transistor (TFT2) 33 is held in the capacitor ( _Cadd ) 32 until the first thin film transistor (TFT1) 31 is next selected for scanning. Therefore, current continues to flow through the organic electroluminescent element 34 until the next scanning is performed. As a result, the organic electroluminescent element 34 can always emit light during one frame period.

  FIG. 4 is a schematic view showing an example of a cross-sectional structure of a TFT substrate used in the display device of FIG. Details of the structure will be described below while showing an example of the manufacturing process of the TFT substrate. When the display device 40 of FIG. 4 is manufactured, a moisture-proof film 42 for protecting a member (TFT or organic layer) formed on the top is first coated on a substrate 41 such as glass. As a material constituting the moisture-proof film 42, silicon oxide or a composite of silicon oxide and silicon nitride is used. Next, a gate electrode 43 is formed by patterning into a predetermined circuit shape by depositing a metal such as Cr by sputtering. Subsequently, silicon oxide or the like is formed by plasma CVD or catalytic chemical vapor deposition (cat-CVD) or the like, and patterned to form the gate insulating film 44. Next, a silicon film is formed by a plasma CVD method or the like (in some cases, annealed at a temperature of 290 ° C. or higher), and a semiconductor layer 45 is formed by patterning according to a circuit shape.

  Further, a drain electrode 46 and a source electrode 47 are provided on the semiconductor film 45 to produce a TFT element 48, thereby forming a circuit as shown in FIG. Next, an insulating film 49 is formed on the TFT element 48. Next, a contact hole (through hole) 50 is formed so that the anode 51 and the source electrode 47 for an organic electroluminescence element made of metal are connected.

  The display device 40 can be obtained by sequentially laminating a multilayer or single layer organic layer 52 and a cathode 53 on the anode 51. At this time, a first protective layer 54 and a second protective layer 55 may be provided in order to prevent deterioration of the organic electroluminescent element. By driving the display device using the organic electroluminescent element of the present invention, it is possible to display with good image quality and stable display for a long time.

  Note that the display device is not particularly limited to a switching element, and can be easily applied to a single crystal silicon substrate, an MIM element, an a-Si type, or the like.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.

  [Synthesis Example 1] Synthesis of Exemplified Compound A-4

(1) Synthesis of intermediate compound D3 The following reagents and solvent were charged into a 200 ml flask. Compound D1 is a compound obtained by synthesis in accordance with the method described in Non-Patent Document 4.
Compound D1: 0.5 g (0.41 mmol)
Compound D2: 0.24 g (0.9 mmol)
Anhydrous sodium carbonate: 0.56 g (5.3 mmol)
Ethyl cellosolve: 15ml
Triethylamine: 5ml

  Next, after making the reaction system into a nitrogen atmosphere, the reaction solution was heated to 110 ° C. and stirred at this temperature (110 ° C.) for 24 hours. After completion of the reaction, the reaction solution was allowed to cool. Next, the yellow solid precipitated when 10 ml of water was put into the reaction solution was collected by filtration. Next, this yellow solid was purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1) to obtain 0.41 g (yield 59%) of intermediate compound D3 as a yellow solid.

(2) Synthesis of Exemplified Compound A-4 The following reagents and solvent were charged into a 100 ml flask.
Intermediate compound D3: 0.195 g (0.23 mmol)
35% hydrogen peroxide solution: 0.54 ml
THF: 15ml

  Next, the reaction solution was stirred at room temperature for 2 days. After completion of the reaction, the yellow solid precipitated when 10 ml of water was added was filtered and washed with water, and then this yellow solid was washed with methanol. Next, the washed yellow solid is purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1), and the solvent is distilled off under reduced pressure, followed by drying under reduced pressure, whereby Example Compound A-4 is obtained. 0.18 g (yield 89%) was obtained as a yellow solid.

881 which is M ^<+> of this compound was confirmed by MALSDI-TOF MS. Λ _max of the phosphorescence emission spectrum of this compound in a toluene solution was 455 nm.

  [Synthesis Example 2] Synthesis of Exemplified Compound A-14

(1) Synthesis of Intermediate Compound D5 The following reagents and solvent were charged in a 200 ml flask.
Compound D1: 0.5 g (0.41 mmol)
Compound D4: 0.27 g (0.9 mmol)
Anhydrous sodium carbonate: 0.56 g (5.3 mmol)
Ethyl cellosolve: 15ml
Triethylamine: 5ml

  Next, after making the reaction system into a nitrogen atmosphere, the reaction solution was heated to 110 ° C. and stirred at this temperature (110 ° C.) for 24 hours. After completion of the reaction, the reaction solution was allowed to cool. Next, the yellow solid precipitated when 10 ml of water was put into the reaction solution was collected by filtration. Next, this yellow solid was purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1) to obtain 0.45 g (yield 63%) of intermediate compound D5 as a yellow solid.

(2) Synthesis of Exemplified Compound A-14 The following reagents and solvent were charged in a 100 ml flask.
Intermediate compound D5: 0.195 g (0.23 mmol)
35% hydrogen peroxide solution: 0.54 ml
THF: 15ml

  Next, the reaction solution was stirred at room temperature for 2 days. After completion of the reaction, the yellow solid precipitated when 10 ml of water was added was filtered and washed with water, and then this yellow solid was washed with methanol. Next, the washed yellow solid is purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1), and the solvent is distilled off under reduced pressure, followed by drying under reduced pressure, whereby Example Compound A-14 is obtained. 0.17 g (yield 84%) was obtained as a yellow solid.

898 which is M ^<+> of this compound was confirmed by MALSDI-TOF MS. Λ _max of the phosphorescence emission spectrum of this compound in a toluene solution was 448 nm.

  [Synthesis Example 3] Synthesis of Exemplified Compound A-54

(1) Synthesis of Intermediate Compound D7 The following reagents and solvent were charged into a 200 ml flask.
Compound D1: 0.5 g (0.41 mmol)
Compound D6: 0.11 g (0.9 mmol)
Anhydrous sodium carbonate: 0.56 g (5.3 mmol)
Ethyl cellosolve: 15ml
Triethylamine: 5ml

  Next, after making the reaction system into a nitrogen atmosphere, the reaction solution was heated to 110 ° C. and stirred at this temperature (110 ° C.) for 24 hours. After completion of the reaction, the reaction solution was allowed to cool. Next, the yellow solid precipitated when 10 ml of water was put into the reaction solution was collected by filtration. Next, this yellow solid was purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1) to obtain 0.38 g (yield 67%) of intermediate compound D7 as a yellow solid.

(2) Synthesis of Exemplified Compound A-54 The following reagents and solvent were charged into a 100 ml flask.
Intermediate compound D7: 0.2 g (0.29 mmol)
35% hydrogen peroxide solution: 0.54 ml
THF: 15ml

  Next, the reaction solution was stirred at room temperature for 2 days. After completion of the reaction, the yellow solid precipitated when 10 ml of water was added was filtered and washed with water, and then this yellow solid was washed with methanol. Next, the washed yellow solid was purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1), the solvent was distilled off under reduced pressure, and the residue was dried under reduced pressure to give Exemplified Compound A-54. 0.15 g (yield 71%) was obtained as a yellow solid.

Confirmed that the M ⁺ of 729 of the compound MALSDI-TOF MS. Λ _max of the phosphorescence emission spectrum of this compound in a toluene solution was 458 nm.

  [Synthesis Example 4] Synthesis of Exemplified Compound A-34

(1) Synthesis of intermediate compound D9 The following reagents and solvent were charged in a 300 ml flask.
Compound D8: 3.0 g (13.7 mmol)
IrCl ₃ .3H ₂ O: 2.11 g (6.0 mmol)
Ethyl cellosolve: 100ml
Water: 50ml

  Next, after making the reaction system into a nitrogen atmosphere, the reaction solution was heated to 115 ° C. and stirred at this temperature (115 ° C.) for 24 hours. After completion of the reaction, the reaction solution was allowed to cool. Next, 50 ml of water was put into the reaction solution, and the yellow solid precipitated was collected by filtration. Next, this yellow solid was washed with methanol and dried to obtain 3.95 g (yield 87%) of intermediate compound D9 as a yellow solid.

(2) Synthesis of Intermediate Compound D10 The following reagents and solvent were charged in a 200 ml flask.
Compound D9: 0.5 g (0.38 mmol)
Compound D4: 0.39 g (1.3 mmol)
Anhydrous sodium carbonate: 0.56 g (5.3 mmol)
Ethyl cellosolve: 15ml
Triethylamine: 5ml

  Next, after making the reaction system into a nitrogen atmosphere, the reaction solution was heated to 110 ° C. and stirred at this temperature (110 ° C.) for 24 hours. After completion of the reaction, the reaction solution was allowed to cool. Next, the yellow solid precipitated when 10 ml of water was put into the reaction solution was collected by filtration. Next, this yellow solid was purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1) to obtain 0.48 g (yield 69%) of intermediate compound D10 as a yellow solid.

(3) Synthesis of Exemplary Compound A-34 The following reagents and solvent were charged into a 100 ml flask.
Intermediate compound D10: 0.4 g (0.43 mmol)
35% hydrogen peroxide solution: 0.54 ml
THF: 15ml

  Next, the reaction solution was stirred at room temperature for 2 days. After completion of the reaction, the yellow solid precipitated when 10 ml of water was added was filtered and washed with water, and then this yellow solid was washed with methanol. Next, the washed yellow solid is purified by silica gel column chromatography (developing solvent: toluene / ethyl acetate = 9/1), and the solvent is distilled off under reduced pressure, followed by drying under reduced pressure, whereby Example Compound A-34 is obtained. 0.26 g (yield 63%) was obtained as a yellow solid.

952 which is M ^<+> of this compound was confirmed by MALSDI-TOF MS. Λ _max of the phosphorescence emission spectrum of this compound in a toluene solution was 445 nm.

Example 1 Production of Organic Electroluminescent Device The organic electroluminescent device shown in FIG. 1B was produced by the following method.

First, an ITO film was formed on a glass substrate (transparent substrate 15) to form an ITO film. At this time, the thickness of the ITO film was set to 100 nm. Next, the transparent electrode 14 was formed by patterning the ITO film into a desired shape by a photolithography process. At this time, the electrode area of the transparent electrode 14 was set to 3.14 mm ² . Next, an organic compound layer and a metal electrode layer were sequentially formed on the transparent substrate 15 on which the transparent electrode 14 was formed by a vacuum deposition method. In addition, the organic compound layer and the metal electrode layer described later were formed under reduced pressure of 1 × 10 ⁻⁴ Pa.

  First, TCTA (4,4 ′, 4 ″ -tris (carbazol-9-yl) -triphenylamine, a product produced by sublimation purification of Aldrich) was formed to form the hole transport layer 13. At this time, the thickness of the hole transport layer 13 was 200 mm.

Next, the following (L1) and (L2) were co-deposited on the hole transport layer 13 so that the deposition rate was 1: 0.1, whereby the light emitting layer 12 was formed. At this time, the thickness of the light emitting layer 12 was set to 400 mm. The light emitting layer 12 is a thin film in which Illustrative Compound A-4 is doped in the light emitting layer 12 by 10% by weight.
(L1) Exemplary Compound A-4
(L2) CDBP (9,9 ′-(2,2′-dimethyl [1,1′-biphenyl] -4,4′-diyl) bis-9-Carbazole, a product produced by sublimation purification of Lumitec)

  Next, Bphen (4,7-diphenyl-1,10-phenanthroline, produced by sublimation purification of Aldrich product) was formed on the light emitting layer 12 to form the electron transport layer 16. At this time, the thickness of the electron transport layer 16 was 200 mm.

  Next, KF (potassium fluoride, manufactured by Aldrich) was formed on the electron transport layer 16 to form a KF film. At this time, the thickness of the KF film was 10 mm. Next, Al was deposited to form an Al film. At this time, the thickness of the Al film was set to 1200 mm. The KF film and the Al film function as the metal electrode 11.

  The organic electroluminescent element was obtained by the above.

  About the obtained element, the performance was evaluated by the method shown below.

(1) External extraction efficiency The obtained organic electroluminescence device was lit at room temperature (about 23 ° C.) and a constant current of ^2.5 mA / cm ² , and the emission luminance (L) [cd / m ² immediately after the start of lighting] ] Was measured to calculate the external extraction efficiency (φ). The light emission luminance was measured with an organic EL light emission characteristic evaluation apparatus (manufactured by Cradle Co.). This device consists of a dark box, luminance meter, multi-channel spectrometer, element drive power supply and analysis device, and is designed to obtain the desired light emission luminance by controlling the drive current and drive voltage to the element by a program. ing.

(2) Chromaticity difference The obtained organic electroluminescent element was lit at room temperature (about 23 ° C.) and a constant current of ^2.5 mA / cm ² , and the CIE chromaticity value (x, y) was measured. In addition, CS-1000 (product made from Minolta) was used for the measuring apparatus.

[3] Luminance half-life The luminance half-life of the obtained organic electroluminescence device was measured using the same apparatus as in the case of the external extraction efficiency. In the measurement, the initial luminance was set to 1000 cd / A, and the time when the initial luminance was attenuated to 50% was defined as the luminance half time.

The organic electroluminescence device of this example showed blue emission with EL _max = 459 nm and CIE chromaticity values (0.16, 0.26). Further, the external quantum efficiency of the organic electroluminescence device of this example was 3.5%.

[Example 2]
In Example 1, the organic electroluminescent element was obtained by the same method as Example 1 except having used exemplary compound A-14 instead of exemplary compound A-4. The performance of the obtained device was evaluated in the same manner as in Example 1. The organic electroluminescence device of this example showed blue emission with EL _max = 450 nm and CIE chromaticity values (0.16, 0.22). In addition, the external quantum efficiency of the organic electroluminescent device of this example was 4.8%.

[Example 3]
In Example 1, the organic electroluminescent element was obtained by the same method as Example 1 except having used exemplary compound A-54 instead of exemplary compound A-4. The performance of the obtained device was evaluated in the same manner as in Example 1. The organic electroluminescent element of this example showed blue light emission with EL _max = 458 nm and CIE chromaticity value (0.16, 0.26). Moreover, the external quantum efficiency of the organic electroluminescent element of this example was 2.3%.

[Example 4]
In Example 1, the organic electroluminescent element was obtained by the same method as Example 1 except having used exemplary compound A-34 instead of exemplary compound A-4. The performance of the obtained device was evaluated in the same manner as in Example 1. The organic electroluminescence device of this example showed blue light emission with EL _max = 445 nm and CIE chromaticity values (0.15, 0.21). Moreover, the external quantum efficiency of the organic electroluminescent element of this example was 1.5%.

[Comparative Example 1]
In Example 1, the following compound 1 (bis [3,5-difluoro-2- (2-pyridinyl- · N) phenyl- · C] (2-pyridinecarboxylato- · N1, • O2) -Iridium) was used. Except for this, an organic electroluminescent element was obtained in the same manner as in Example 1. In addition, the compound used in this comparative example is a product obtained by sublimation purification of a commercially available product (manufactured by Lumitec). Further, λ _max of the phosphorescence emission spectrum of a toluene solution of Compound 1 shown below is 472 nm. The performance of the obtained device was evaluated in the same manner as in Example 1. The organic electroluminescent element of this example obtained blue-green light emission with EL _max = 472 nm and CIE chromaticity values (0.17, 0.38). Moreover, the external quantum efficiency of the organic electroluminescent element of this comparative example was 3.1%.

[Comparative Example 2]
In Example 1, the following compound 2 (bis [3,5-difluoro-2- (2-pyridinyl- · N) phenyl- · C] [tetrakis (1H-pyrazolato- · N1) borato (1-)-. N2, .N2 ']-, (OC-6-33) -Iridium). Except for this, an organic electroluminescent element was obtained in the same manner as in Example 1. In addition, the compound used in this comparative example is a product obtained by sublimation purification of a commercially available product (manufactured by Lumitec). Further, λ _max of the phosphorescence emission spectrum of a toluene solution of Compound 1 shown below is 460 nm. The performance of the obtained device was evaluated in the same manner as in Example 1. The organic electroluminescent element of this comparative example emitted blue-green light with EL _max = 469 nm and CIE chromaticity values (0.17, 0.31). The external quantum efficiency of the organic electroluminescent device of this comparative example was 2.2%.

  Here, the emission peak wavelengths showing the 0-0 transition of the phosphorescence emission spectra of the compounds used in Examples and Comparative Examples are compared as shown in the following table.

  From the above table, the difference in emission peak wavelength showing 0-0 transition was clear. Moreover, it was shown that the compound of a present Example has the light emission peak requested | required as a blue light-emitting material.

  1a (1b, 1c, 34): organic electroluminescent element, 11: metal electrode, 12: light emitting layer, 13: hole transport layer, 14: transparent electrode, 15: transparent substrate, 16: electron transport layer, 17: exciton Diffusion prevention layer, 20: image display device, 21: scanning signal driver, 22: information signal driver, 23: current supply source, 30: pixel circuit, 31: first thin film transistor (TFT), 32: capacitor, 33: first Second thin film transistor (TFT), 35: cathode

Claims (5)

An anode and a cathode;
An organic compound layer sandwiched between the anode and the cathode and having at least a light-emitting layer,
The light emitting layer is bonded to any of the following bond types (a) to Ir-SO:
(B) Ir-SO ₂
(C) Pt-SO
(D) Pt—SO ₂
The organic electroluminescent element characterized by including the metal complex compound containing this. The organic electroluminescent element according to claim 1, wherein the metal complex compound is a compound represented by the following general formula (1a) or (1b).

(In the formulas (1a) and (1b), M represents an iridium atom or a platinum atom. N is 1 or 2. Q _{1 to} Q ₁₂ are a nitrogen atom or CR ₁ (R ₁ is a hydrogen atom, respectively). Represents an atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted aryl group, m is an integer of 0 to 2, and l is 1 Is an integer of 1 to 3. However, m + 1 is 2 or 3. In (1a), X ₁ is a nitrogen atom or a phosphorus atom, and the nitrogen atom and the phosphorus atom may have a substituent. (In (1b), X ₂ is an oxygen atom or a sulfur atom.) The organic electroluminescent element according to claim 1, wherein the metal complex compound is a compound represented by the following general formula (2).

(In Formula (2), M represents an iridium atom or a platinum atom. N is 1 or 2. Y is an oxygen atom or C (R ₂ ) ₂ (R ₂ is a hydrogen atom, a fluorine atom, Represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group, or a substituted or unsubstituted aryl group.) Q _{13 to} Q ₂₄ are each a nitrogen atom or CR ₃ (R ₃ is a hydrogen atom) Represents a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted aryl group, m is an integer of 0 to 2, and l is 1 to (It is an integer of 3. However, m + 1 is 2 or 3.) The organic electroluminescent element according to claim 1, wherein the metal complex compound is a compound represented by the following general formula (3a) or (3b).

(In the formulas (3a) and (3b), M represents an iridium atom or a platinum atom. N is 1 or 2. Z is a nitrogen atom or a carbon atom. Q _{25 to} Q ₃₇ are respectively Represents a nitrogen atom or CR ₄ (R ₄ represents a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted aryl group), and m is 0. 1 is an integer of 1 to 2, and l is an integer of 1 to 3. However, m + 1 is 2 or 3. In Formula (3a), X ₁ is a nitrogen atom or a phosphorus atom. (The phosphorus atom may have a substituent. In Formula (3b), X ₂ is an oxygen atom or a sulfur atom.)   A display device comprising: the organic electroluminescent element according to claim 1; and a thin film transistor.

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