WO2009011447A2 - Iridium complex compounds, organic electroluminescent devices and uses thereof - Google Patents
Iridium complex compounds, organic electroluminescent devices and uses thereof Download PDFInfo
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Abstract
Blue-emitting phosphorescent compounds show high solubility in solvents for coating solutions in the production of organic EL devices and have excellent thermal stability. Organic EL devices having the blue-emitting phosphorescent compounds have high luminous efficiency and long life. A blue-emitting phosphorescent compound is an iridium complex compound represented by Formula (1) below: wherein R1 is a C2-30 organic group; R2 to R4 are each independently a hydrogen atom or a C1-10 alkyl group; R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, C1-10 fluorine-substituted alkyl groups, C1-10 fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, C1-10 aminocarbonyl groups, thiocyanate group and C1-10 sulfonyl groups, a C1-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom; and at least one of R5 to R8 is the electron-withdrawing group.
Description
DESCRIPTION
IRIDIUM COMPLEX COMPOUNDS, ORGANIC ELECTROLUMINESCENT DEVICES
AND USES THEREOF
FIELD OF THE INVENTION [0001]
The present invention relates to luminescent metal complex compounds, organic electroluminescent devices manufactured with the luminescent metal complex compounds, and uses of the devices.
BACKGROUND OF THE INVENTION [0002]
Phosphorescent compounds have high luminous efficiency and are actively studied as luminescent materials for organic electroluminescent devices (in the present specification, also referred to as the organic EL devices) . [0003]
Organic EL devices having phosphorescent compounds are expected to have a wider range of applications. It is therefore essential particularly in the display field that materials are developed which have high luminous efficiency and continue to stably operate the device. [0004]
Of the three primary colors required for full color
display, organic EL devices emitting green and red lights have used phosphorescent compounds having luminous efficiency, durability and solubility that meet a practical level.
However, no such phosphorescent compounds have been developed for blue-emitting organic EL devices.
[0005]
It is therefore desired that blue-emitting phosphorescent compounds with high luminous efficiency and high durability are developed. JP-A-2003-526876 (Patent Document 1) teaches that the use of an organic iridium complex as a phosphorescent compound greatly enhances the luminous efficiency of organic EL devices.
Tris (2- (2-pyridyl) phenyl) iridium and derivatives thereof are shown as examples of the iridium complexes, and it is described that the iridium complexes emit different colors by changing substituent groups of the aromatic ligand to alkyl groups or aryl groups .
[0006]
JP-A-2001-247859 (Patent Document 2) describes various groups as examples of the substituent groups for tris (2- (2-pyridyl) phenyl) iridium.
JP-A-2002-170684 (Patent Document 3) discloses high efficiency luminescent devices, and describes iridium complexes with phosphorus-containing ligands as novel metal
complexes enabling such devices.
[0007]
JP-A-2004-506305 (Patent Document 4) describes blue-emitting metal complex compounds. The metal complex compounds described in this document contain iridium.
On the other hand, the vacuum vapor deposition of low molecular organic compounds and the coating of high molecular compound solutions are usual methods for forming luminescent layers in organic EL devices. The coating method is advantageous in terms of low production cost of the devices and easy production of large-area devices.
[0008]
However, conventional blue-emitting phosphorescent compounds have poor solubility and cause problems in film production by coating. It is known that the solubility of the blue-emitting phosphorescent compounds is increased by introducing long-chain alkyl groups to the aromatic ligands.
For example, Polyhedron 25 (Non-Patent Document 1) describes iridium complexes in which a hexyloxy group is introduced in an aromatic ligand (see Formulae (4) and (5) below).
[0009]
[0011]
However, the compounds of Formulae (4) and (5) have poor thermal stability, and organic EL devices having these compounds have low durability.
[Patent Document 1] JP-A-2003-526876
[Patent Document 2] JP-A-2001-247859
[Patent Document 3] JP-A-2002-170684 [Patent Document 4] JP-A-2004-506305
[Non-Patent Document 1] Inamur R. Laskar, Shin-Feng Hsu,
Teng-Ming Chen, "Investigating photoluminescence and electroluminescence of iridium (III) -based blue-emitting phosphors", Polyhedron, 2006, 25, pp. 1167-1176
SUMMARY OF THE INVENTION
[0012]
It is an object of the invention to provide blue-emitting phosphorescent compounds that show high solubility in solvents for coating solutions in the production of organic EL devices
and have excellent thermal stability.
It is another object of the invention to provide organic EL devices having the blue-emitting phosphorescent compounds that have high luminous efficiency and long life. [0013]
The present inventors have diligently studied to solve the above problems. They have then found that blue-emitting phosphorescent iridium complex compounds having a specific structure show high solubility in solvents for coating solutions in the production of organic EL devices and have excellent thermal stability. The inventors have also found that coating solutions of the iridium complex compounds can be applied to substrates uniformly and have good film-forming properties in the production of organic EL devices, and that organic EL devices having the iridium complex compounds in luminescent layers have high luminous efficiency and long life. The present invention has been completed based on the findings. The present invention relates to the following. [0014] [1] An iridium complex compound represented by Formula (1) below: [0015]
[0016] wherein R1 is a C2-30 organic group;
R2 to R4 are each independently a hydrogen atom or a Cl-10 alkyl group;
R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, Cl-10 fluorine-substituted alkyl groups, Cl-10 fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-10 aminocarbonyl groups, thiocyanate group and Cl-10 sulfonyl groups, a Cl-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom; and at least one of R to R is the electron-withdrawing group.
[2] The iridium complex compound described in [1], wherein the electron-withdrawing group is a fluorine atom, a Cl-10 fluorine-substituted alkyl group, a Cl-10 fluorine-substituted alkoxy group or a cyano group.
[3] The iridium complex compound described in [1] or [2], which is represented by Formula (2) below: [0017]
[0018] wherein R1 is a C2-30 organic group; and
R2 to R4 are each a hydrogen atom or a Cl-10 alkyl group.
[4] The iridium complex compound described in any one of [1] to [3] , which is represented by Formula (3) below: [0019]
[0020] wherein R1 is a C2-30 organic group.
[5] The iridium complex compound described in any one of [1] to [4], wherein R1 is a C2-30 alkyl group or a C7-30
aralkyl group.
[6] The iridium complex compound described in any one of [1] to [5] , which is a facial complex. [0021] [7] An organic electroluminescent device comprising a substrate, a pair of electrodes formed on the substrate, and one or plural organic layers including a luminescent layer which are formed between the pair of the electrodes, wherein the luminescent layer comprises the iridium complex compound described in any one of [1] to [6]. [0022]
[8] The organic electroluminescent device described in [7], wherein the luminescent layer contains a charge-transporting non-conjugated polymer compound. [0023]
[9] An image display device prepared using the organic electroluminescent device described in [7] or [8].
[0024]
[10] A plane light source prepared using the organic electroluminescent device described in [7] or [8].
[11] A process for producing the iridium complex compound described in [1] which comprises reacting iridium (III) chloride trihydrate and a phenylpyridine derivative represented by Formula (1-1) below in an alcohol/water mixed
solvent with heating to obtain a binuclear iridium complex represented by Formula (1-2) below, and reacting the binuclear complex and a phenylpyridine derivative represented by Formula (1-1) in a solvent in the presence of a silver salt and/or a base with heating; [0025]
(1-2)
[0026] in Formulae (1-1) and (1-2), R1 is a C2-30 organic group;
R2 to R4 are each independently a hydrogen atom or a Cl-10 alkyl group;
R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, Cl-10 fluorine-substituted alkyl groups, Cl-10 fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-10 aminocarbonyl groups, thiocyanate group and Cl-10 sulfonyl groups, a Cl-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom;
and at least one of R5 to R8 is the electron-withdrawing group. [0027] The patent documents mentioned above do not teach that the life of organic EL devices is enhanced by appropriately selecting the kind, number and position of substituent groups in the ligand. [0028] The blue-emitting iridium complex compounds according to the invention show high solubility in solvents for coating solutions in the production of organic EL devices and have excellent thermal stability. The organic EL devices having the iridium complex compounds have high luminous efficiency and long life. The coating solutions of the iridium complex compounds can be applied to substrates uniformly and have good film-forming properties in the production of organic EL devices .
BRIEF DESCRIPTION OF THE DRAWING
Fig. 1 is a cross-sectional view of an organic EL device according to an embodiment of the present invention, wherein:
1: Glass substrate 2 : Anode
3: Luminescent layer 4 : Cathode
BEST MODE FOR CARRYING OUT THE INVENTION [0029]
The present invention will be described in detail hereinbelow. <Iridium complex compounds>
An iridium complex compound used in the invention is represented by Formula (1) below: [0030]
[0031] wherein R1 is a C2-30 organic group;
R2 to R4 are each independently a hydrogen atom or a Cl-10 alkyl group;
R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, Cl-10 fluorine-substituted alkyl groups, Cl-10 fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-10
aminocarbonyl groups, thiocyanate group and Cl-IO sulfonyl groups, a Cl-IO organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom; and at least one of R5 to R8 is the electron-withdrawing group.
For the iridium complex compound to achieve high solubility in solvents for coating solutions in the production of organic EL devices, R1 in Formula (1) is a C2-30 organic group, preferably a C2-30 alkyl group or a C7-30 optionally substituted aralkyl group, and more preferably a C3-30 alkyl group having a branched structure and/or a ring structure, or a C8-30 aralkyl group having a branched structure. Specific examples include ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, 1-pentyl, 2-pentyl, 3-pentyl,
3-methylbutyl, 1, 1-dimethylpropyl, n-hexyl, 2-hexyl, 3-hexyl, 4-methylpentyl, 2-ethylbutyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, n-octyl, 2-octyl, 3-octyl, 4-octyl, n-ethylhexyl, n-nonyl, 2-nonyl, 3-nonyl, 4-nonyl, 5-nonyl, n-decyl, 3, 7-dimethyloctyl, n-dodecyl, n-tetradecyl, n-hexadecyl, 2-methylhexadecyl, n-octadecyl, n-eicosyl, n-docosyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclohexylmethyl, adamantyl, 3, 5-dimethyladamantyl, benzyl, 1-phenylethyl, 2-phenylethyl,
2- (1-phenyl) propyl and 3, 3-diphenylpropyl groups. Of these, isopropyl, 2-butyl, isobutyl, tert-butyl, 2-pentyl, 3-pentyl, 3-methylbutyl, 1, 1-dimethylpropyl, 2-hexyl, 3-hexyl, 4-methylpentyl, 2-ethylbutyl, 2-heptyl, 3-heptyl, 4-heptyl, 2-octyl, 3-octyl, 4-octyl, 2-ethylhexyl, 2-nonyl, 3-nonyl, 4-nonyl, 5-nonyl, 3, 7-dimethyloctyl, 2-methylhexadecyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclohexylmethyl, adamantyl, 3, 5-dimethyladamantyl, 1-phenylethyl, 2-phenylethyl, 2- (1-phenyl) propyl and 3, 3-diphenylpropyl groups are preferred, and 2-butyl, 2-pentyl, 2-ethylhexyl, cyclopentyl, cyclohexyl, cyclohexylmethyl and adamantyl groups are more preferred. [0032] To achieve high thermal stability, R2 to R4 in Formula (1) are preferably each independently a hydrogen atom or a Cl-10 alkyl group.
Specific examples include hydrogen atom and methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, tert-butyl, 1-pentyl, 2-pentyl, 3-pentyl, 3-methylbutyl,
1, 1-dimethylpropyl, n-hexyl, 2-hexyl, 3-hexyl, 4-methylpentyl, 2-ethylbutyl, n-heptyl, 2-heptyl, 3-heptyl, 4-heptyl, n-octyl, 2-octyl, 3-octyl, 4-octyl, n-ethylhexyl, n-nonyl, 2-nonyl, 3-nonyl, 4-nonyl, 5-nonyl and n-decyl groups .
Of these, hydrogen atom, methyl group and ethyl group are preferred, and hydrogen atom is particularly preferred. [0033]
For the complex compound to achieve blue-emitting properties, at least one of R5 to R8 in Formula (1) is an electron-withdrawing group. Preferred electron-withdrawing groups include halogen atoms, Cl-10 fluorine-substituted alkyl groups, Cl-10 fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-10 aminocarbonyl groups, thiocyanate group and Cl-10 sulfonyl groups. The electron-withdrawing group is more preferably a fluorine atom, a Cl-10 fluorine-substituted alkyl group, a Cl-10 fluorine-substituted alkoxy group or a cyano group. [0034]
Specific examples include fluorine, chlorine, bromine and iodine atoms, and trifluoromethyl, trifluoromethoxy, cyano, aldehyde, acetyl, benzoyl, methoxycarbonyl, phenoxycarbonyl, dimethylaminocarbonyl, thiocyanate, methylsulfonyl and phenylsulfonyl groups . Of these, fluorine atom, trifluoromethyl group, trifluoromethoxy group and cyano group are preferred, and fluorine atom is particularly preferred. [0035]
Of R5 to R8 in Formula (1), the groups other than the electron-withdrawing group (s) are each a Cl-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom. [0036]
Of the iridium complex compounds according to the present invention, the compounds represented by Formula (2) below are preferable because of higher solubility in solvents for coating solutions in the production of organic EL devices and superior thermal stability. [0037]
[0038] wherein R1 is a C2-30 organic group; and
R2 to R4 are each a hydrogen atom or a Cl-10 alkyl group.
Further, the compounds of Formula (3) below are more preferable . [0039]
[0040] wherein R1 is a C2-30 organic group.
The iridium complex compounds are preferably facial complexes, in which case the compounds show improved luminescence properties. [0041]
The iridium complex compounds of the invention are superior in thermal stability to conventional blue-emitting phosphorescent compounds such as shown below, because of the absence of a picolinic acid ligand having a weak bond with the iridium atom. [0042]
<Process for producing iridium complex compounds>
The iridium complex compounds of the invention may be produced by any methods without limitation. An exemplary method is given below. [0044]
(1-2)
(D
[0045]
The production of the iridium complex compounds will be described below with reference to the above exemplary reaction scheme .
First, iridium (III) chloride trihydrate and a phenylpyridine derivative (1-1) are reacted in an alcohol/water mixed solvent with heating to give a binuclear iridium complex (1-2) . The heating may be conducted under
reflux. Examples of the alcohols in the mixed solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol, 2-methoxyethanol, 2-ethoxyethanol, ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 3-butanediol, 1, 4-butanediol, diethylene glycol and diethylene glycol monomethyl ether. The ratio (alcohol: water (by volume) ) of the alcohol and water in the mixed solvent is 1-99:1. Examples of the mixed solvents include (2-ethoxyethanol : water = 3:1 (by volume)). [0046]
In Formulae (1-1) and (1-2), R1 to R8 are the same as R1 to R8 in Formula (1) .
Next, the binuclear complex and a phenylpyridine derivative (1-1) are reacted in a solvent in the presence of a silver salt and/or a base with heating to give an iridium complex compound (1) according to the present invention. The heating may be conducted under reflux. Examples of the bases include inorganic bases such as sodium carbonate and potassium carbonate, and organic bases such as tributylamine and lutidine. Examples of the silver salts include silver (I) oxide, silver (I) sulfide, silver (I) sulfate, silver (I) nitrate, silver (I) phosphate, silver (I) acetate, silver (I) trifluoroacetate, silver (I) p-toluenesulfonate, silver (I) methanesulfonate and silver (I) trifluoromethanesulfonate .
[ 0047 ]
In the second reaction step, the use of toluene as the solvent results in a mixture of facial and meridional iridium complex compounds. If a solvent of higher boiling point such as mesitylene is used, a facial iridium complex compound may be produced with high yield and high selectivity.
<0rganic EL devices>
An organic EL device according to the present invention includes a substrate, a pair of electrodes formed on the substrate, and one or plural organic layers including a luminescent layer which are formed between the pair of the electrodes, wherein the luminescent layer contains the iridium complex compound of the invention.
[0048] In the organic EL device, the luminescent layer preferably contains a charge-transporting non-conjugated polymer compound.
One example of the structures of the organic EL devices according to the present invention is shown in Fig. 1, but the structure of the organic EL devices according to the present invention is not limited thereto. In Fig. 1, a luminescent layer 3 is provided between an anode 2 and a cathode 4 which are provided on a transparent substrate 1. In the organic EL device, a hole-injection layer may be provided between the
anode 2 and the luminescent layer 3, and an electron-injection layer may be provided between the luminescent layer 3 and the cathode 4. [0049] The organic layer including the iridium complex compound and the charge-transporting non-conjugated polymer compound functions as a luminescent layer having both hole-transporting properties and electron-transporting properties. This provides an advantage that the organic EL device shows high luminous efficiency without other organic material layers. [0050]
The organic layer may be produced without limitation, for example as follows. First, a solution of the iridium complex compound and the charge-transporting non-conjugated polymer compound is prepared. The solvent used herein is not particularly limited. Examples of the solvents include chlorine-containing solvents such as chloroform, methylene chloride and dichloroethane; ether solvents such as tetrahydrofuran and anisole; aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as acetone and methyl ethyl ketone; and ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate. Next, the solution prepared as described above is applied on a substrate to form a film. Herein, any of an ink jet method,
a spin coating method, a dip coating method and a printing method may be employed. [0051]
The iridium complex compound of the invention has high solubility in the solvents, and the solution of the compound can form a uniform film of the compound on the substrate. [0052]
The solution concentration depends on the compound used and the film-forming conditions. In the case of the spin coating method or the dip coating method, the concentration is preferably 0.1 to 10 wt% . The high solubility of the iridium complex compound in solvents leads to easy film-production and simplified production steps and enables the production of large-area organic EL devices. [0053]
The iridium complex compounds may be used singly in the luminescent layer of the organic EL device, or two or more kinds may be used in combination.
The organic EL devices having the luminescent layer of the iridium complex compound have long life and high luminous efficiency. [0054] <Other materials>
The layers in the EL device may be formed with a polymer
material as a binder. Examples of the polymer materials include polymethyl methacrylates, polycarbonates, polyesters, polysulfones and polyphenylene oxides. [0055] Further, the layers may be formed by mixing materials having different functions, for example, by mixing a luminescent material, a hole-transporting material, an electron-transporting material and the like. The organic layer including the iridium complex compound may further contain other hole-transporting material and/or electron-transporting material to increase the charge-transporting properties. Such transporting materials may be low molecular compounds or high molecular compounds. [0056] Examples of the hole-transporting materials for forming the hole-transporting layer and of the hole-transporting materials mixed in the luminescent layer include TPD (N, N' -dimethyl-N,N' - (3-methylphenyl) -1, 1' -biphenyl-4, 4' -di amine) ; α-NPD (4 , 4' -bis [N- (1-naphthyl) -N-phenylamino] biphenyl) ; low molecular triphenylamine derivatives such as m-MTDATA (4,4',4"-tris (3-methylphenylphenylamino) triphenylamine) ; polyvinylcarbazole; high molecular compounds prepared by polymerizing the triphenylamine derivatives described above
into which polymerizable substituent groups are introduced; and fluorescent high molecular compounds such as polyparaphenylenevinylene and polydialkylfluorenes . The high molecular compounds described above include high molecular compounds with a triphenylamine skeleton disclosed in JP-A-H08-157575. The hole-transporting materials may be used singly or in combination of two or more kinds, and different hole-transporting materials may be used as a laminate. The thickness of the hole-transporting layer depends on the conductivity of the hole-transporting layer and is variable. Preferably, the thickness is 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. [0057] Examples of the electron-transporting materials for forming the electron-transporting layer and of the electron-transporting materials mixed in the luminescent layer include quinolinol derivative metal complexes such as Alq3 (aluminum trisquinolinolate) ; low molecular compounds such as oxadiazole derivatives, triazole derivatives, imidazole derivatives, triazine derivatives and triarylborane derivatives; and high molecular compounds prepared by polymerizing the low molecular compounds described above into which polymerizable substituent groups are introduced. The
high molecular compounds described above include poly-PBD disclosed in JP-A-H10-1665. The electron-transporting materials may be used singly or in combination of two or more kinds, and different electron-transporting materials may be used as a laminate. The thickness of the electron-transporting layer depends on the conductivity of the electron-transporting layer and is variable. Preferably, the thickness is 1 nm to 5 μm, more preferably 5 nm to 1 μm, and particularly preferably 10 nm to 500 nm. [0058]
A hole-blocking layer may be provided adjacent to the luminescent layer on the cathode side for the purposes of inhibiting the holes from passing through the luminescent layer and of allowing the holes and electrons to recombine efficiently in the luminescent layer . The hole-blocking layer may be produced using publicly known materials such as triazole derivatives, oxadiazole derivatives and phenanthroline derivatives . [0059] A hole-injection layer may be provided between the anode and the luminescent layer in order to facilitate the injection of holes or to reduce the injection barrier. The hole-injection layer may be produced using publicly known materials such as copper phthalocyanine, a mixture of
polyethylenedioxythiophene (PEDOT) and polystyrenesulfonic acid (PSS) , and fluorocarbon.
[0060]
To improve the electron injecting efficiency, an insulating layer having a thickness of 0.1 to 10 nm may be provided between the cathode and the electron-transporting layer or between the cathode and the organic layer laminated adjacent to the cathode. The insulating layer may be formed using publicly known materials such as lithium fluoride, magnesium fluoride, magnesium oxide and alumina. [0061]
The anode may be formed of publicly known transparent conductive materials such as ITO (indium tin oxide) , tin oxide, zinc oxide, and conductive polymers including polythiophene, polypyrrole and polyaniline. The electrode formed of the transparent conductive material preferably has a surface resistance of 1 to 50 Ω/square. The anode preferably has a thickness of 50 to 300 nm. [0062] The cathode may be formed of publicly known cathode materials such as alkali metals such as Li, Na, K and Cs; alkali earth metals such as Mg, Ca and Ba; Al; MgAg alloys; and alloys of Al and alkali metals or alkali earth metals such as AlLi and AlCa. The cathode preferably has a thickness of 10 nm to
1 μm, and more preferably 50 to 500 nm. When the cathode is formed using a metal having high activity such as alkali metal or alkali earth metal, the thickness of the cathode is preferably 0.1 to 100 nm, and more preferably 0.5 to 50 nm. In this case, a metal layer that is stable to air is laminated on the cathode for the purpose of protecting the cathode metal. Examples of the metals for forming the metal layer include Al, Ag, Au, Pt, Cu, Ni and Cr. The metal layer preferably has a thickness of 10 nm to 1 μm, and more preferably 50 to 500 nm. [0063]
The substrate of the organic EL device may be an insulating substrate that is transparent at an emission wavelength of the luminescent material. Examples include glass, and transparent plastics such as PET (polyethylene terephthalate) and polycarbonate. [0064]
Exemplary methods for forming the hole-transporting layer, the luminescent layer and the electron-transporting layer include a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method, an ink jetting method, a spin coating method, a printing method, a spraying method, and a dispenser method. In the case of the low molecular compounds, the resistance heating vapor deposition method or the electron beam vapor deposition method
is suitably used. For the high molecular compounds, the ink jetting method, the spin coating method or the printing method is suitably used. [0065] Exemplary methods for forming the anode include an electron beam vapor deposition method, a sputtering method, a chemical reaction method and a coating method. Exemplary methods for forming the cathode include a resistance heating vapor deposition method, an electron beam vapor deposition method, a sputtering method and an ion plating method. [0066] <Charge-transporting non-conjugated polymer compounds>
The charge-transporting non-conjugated polymer compound is preferably a polymer obtained by copolymerizing monomers including at least one polymerizable compound selected from the group consisting of hole-transporting polymerizable compounds and electron-transporting polymerizable compounds. In the present specification, the hole-transporting polymerizable compounds and the electron-transporting polymerizable compounds are collectively referred to as the charge-transporting polymerizable compounds. [0067]
In detail, the charge-transporting non-conjugated
polymer compound is preferably a polymer that comprises structural units derived from at least one hole-transporting polymerizable compound, or structural units derived from at least one electron-transporting polymerizable compound. The use of this polymer provides advantages that the charge mobility in the luminescent layer is high, and the luminescent layer can be formed with uniformity in small thickness by coating and consequently high luminous efficiency is obtained. [0068] Further, the charge-transporting non-conjugated polymer compound is more preferably a polymer that comprises structural units derived from at least one hole-transporting polymerizable compound and structural units derived from at least one electron-transporting polymerizable compound. Because this polymer is endowed with hole-transporting properties and electron-transporting properties, holes and electrons are more efficiently recombined in the vicinity of the phosphorescent compound, and therefore higher luminous efficiency is obtained. [0069]
The hole-transporting polymerizable compounds and the electron-transporting polymerizable compounds are not particularly limited as long as they have groups with polymerizable functional groups, and publicly known
charge-transporting compounds may be used. [0070]
The polymerizable functional groups may be any of radically polymerizable functional groups, cationically polymerizable functional groups, anionically polymerizable functional groups, addition-polymerizable functional groups and condensation-polymerizable functional groups. Of these, the radically polymerizable functional groups are preferred because the polymer may be easily produced. [0071]
Examples of the polymerizable functional groups include allyl groups, alkenyl groups, acrylate groups, methacrylate groups, urethane (meth) acrylate groups such as methacryloyloxyethyl carbamate, vinylamide groups and derivatives thereof. Of these, the alkenyl groups are preferred. [0072]
For the alkenyl groups as the polymerizable functional groups, preferred examples of the groups with the polymerizable functional groups include those represented by Formulae (Al) to (A12) below. Of these, the groups represented by Formulae (Al), (A5) , (A8) and (A12) are more preferred because they permit easy introduction of the polymerizable functional groups into the charge-transporting compounds.
[0073]
(A12)
[0074]
Preferred examples of the hole-transporting polymerizable compounds include compounds represented by Formulae (El) to (E6) below. In particular, the compounds
represented by Formulae (El) to (E3) are more preferred from the viewpoint of charge mobility in the non-conjugated polymer compound. [0075]
(E1) (E2) |E3)
(E4) (ES) (Eβ)
[0076]
Preferred examples of the electron-transporting polymerizable compounds include compounds represented by Formulae (E7) to (E15) below. In particular, the compounds represented by Formulae (E7) and (E12) to (E14) are more preferred from the viewpoint of charge mobility in the non-conjugated polymer compound. [0077]
(E7) (E8) (EB)
(E10) (E11) (E12)
(£13) (E14) <E15)
[0078]
Compounds corresponding to Formulae (El) to (E15) except that the group represented by Formula (Al) is altered to the
groups represented by Formulae (A2) to (A12) may be suitably used. In particular, the compounds having the groups represented by Formulae (Al) and (A5) are preferable because the functional groups may be readily introduced into the polymerizable compounds. [0079]
More preferably, the hole-transporting polymerizable compound represented by any of Formulae (El) to (E3) and the electron-transporting polymerizable compound represented by any of Formulae (E7) and (E12) to (E14) are copolymerized. The obtainable non-conjugated polymer compound provides advantages that holes and electrons are more efficiently recombined on the phosphorescent compound, and higher luminous efficiency is obtained. Further, the obtainable non-conjugated polymer compound together with the phosphorescent compound can form an evenly distributed organic layer, and the organic EL device shows excellent durability. [0080]
In an embodiment of the organic EL devices according to the present invention in which the organic layer (luminescent layer) contains the iridium complex compound and the non-conjugated polymer compound, the iridium complex compound is dispersed in a matrix formed by the non-conjugated polymer compound. Because of this structure, the organic layer can
emit light that is usually difficult to produce, that is, light which is emitted through a triplet excitation state of the phosphorescent compound. Accordingly, the organic layer enables high luminous efficiency. [0081]
The charge-transporting non-conjugated polymer compound may further contain structural units derived from other polymerizable compounds while still achieving the objects of the present invention. Examples of such polymerizable compounds include, but are not limited to, compounds having no charge-transporting properties such as alkyl (meth) acrylates including methyl acrylate and methyl methacrylate, styrene and derivatives thereof. [0082] The charge-transporting non-conjugated polymer compounds preferably have a weight average molecular weight of 1,000 to 2, 000, 000, and more preferably 5, 000 to 1,000, 000. The molecular weight in the present specification is a polystyrene-equivalent molecular weight measured by GPC (gel permeation chromatography) . When the molecular weight is in the above range, the polymer is soluble in organic solvents, and a homogeneous thin film is obtained. [0083]
The charge-transporting non-conjugated polymer
compound may be any of a random copolymer, a block copolymer and an alternating copolymer.
The charge-transporting non-conjugated polymer compounds may be produced by any of radical polymerization, cationic polymerization, anionic polymerization and addition polymerization. The radical polymerization is preferred.
<Uses>
The organic EL devices according to the present invention may be suitably used as pixels for known image display devices of matrix system or segment system. Further, the organic EL devices may be suitably used as plane light sources without forming pixels.
[0084]
Specifically, the organic EL devices according to the present invention may be suitably used for display devices in computers, televisions, mobile terminals, portable phones, car navigation systems, viewfinders of video cameras and the like, and may be suitably used for backlights, electrophotography light sources, illumination light sources, recording light sources, exposure light sources, reading light sources, indicators, advertising displays, interiors, optical communications and the like.
EXAMPLES
[ 0085 ]
The present invention will be explained below with reference to examples, but the present invention is not limited to these examples. <Measuring apparatus and the like> 1) 1H-NMR
Apparatus: JNM EX270 manufactured by JEOL Ltd.,
270 MHz
Solvent: deuterated chloroform [Synthetic Example 1]
(Synthesis of iridium complex compound (4a) ) [0086]
(3a): R = n-Butyl (3b): R = a-Butyl (3c) : R = 2-Ethylhexyl
AgOTf mβsitylena
(4a): R = π-Butyl (4b): R = 2-Butyl (4c); R = 2-Ethylheκyl
[ 0087 ]
The synthesis will be described with reference to the above reaction scheme. <Synthesis of 2-chloro-4-hydroxypyridine>
In a recovery flask, 4-amino-2-chloropyridine (3.0 g, 23.3 mmol) was dissolved in 40% sulfuric acid (50 g) . While the solution was stirred at 00C, sodium nitrite (1.93 g, 28.0 mmol) was added. The mixture was stirred at room temperature for 24 hours. After the reaction completed, the reaction
liquid was neutralized by adding an aqueous sodium hydroxide solution and an aqueous sodium hydrogencarbonate solution. The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, distilled to remove the solvent, and dried under reduced pressure to give 2-chloro-4-hydroxypyridine (light brown solid). The solid weighed 2.78 g, and the yield was 92%. [0088]
1H-NMR (270 MHz, DMSO-d6) ppm: 11.20 (s, IH, -OH), 8.09 (d, IH, J = 5.4 Hz, ArH), 6.81 (s, IH, ArH), 6.77 (d, IH, J = 2.2 Hz, ArH) . <Synthesis of compound (Ia) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the 2-chloro-4-hydroxypyridine prepared above (2.6 g, 20mmol) and potassium carbonate (5.5 g, 40 mmol) , and was purged with nitrogen. Dehydrated DMF (80 ml) and 1-bromobutane (4.1 g, 30 mmol) were added, and the mixture was stirred at 1000C for 3 hours. After the reaction completed, toluene was added and the reaction liquid was washed with purified water two times. The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, distilled to remove the solvent, and dried under reduced pressure to give a compound (Ia) (colorless liquid). The
product weight was 3.6 g, and the yield was 97%.
[0089]
<Synthesis of compound (2a) >
A three-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (Ia) (3.6 g, 19.4 mmol) , 2, 4-difluorophenylboronic acid (3.7 g, 23.3 mmol) , potassium carbonate (5.5 g, 40 mmol), 1, 2-dimethoxyethane (50 ml) and purified water (20 ml). Nitrogen was bubbled through the liquid for 5 minutes . Further, [1,1' -bis (diphenylphosphino) ferrocene] dichloropalladium
(II) dichloromethane complex (326 mg, 0.4 mmol) was added. The mixture was stirred under reflux for 3 hours. After the reaction completed, the reaction liquid was cooled to room temperature and purified water was added. The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, and distilled to remove the solvent. The residue was purified by medium pressure silica gel column chromatography (eluting solution: chloroform) , then distilled to remove the solvent, and dried under reduced pressure to give a compound (2a) (colorless liquid) . The product weight was 4.57 g, and the yield was 90% . [0090] <Synthesis of compound (3a) >
A two-necked flask equipped with a Dimroth condenser and
a three-way cock was charged with the compound (2a) (2.0 g, 7.6 mmol) , iridium (III) chloride trihydrate (1.07 g, 3.04 mmol) , 2-ethoxyethanol (36 ml) and purified water (12 ml) . Nitrogen was bubbled through the liquid, and thereafter the mixture was stirred under reflux for 22 hours. After the reaction completed, the reaction liquid was cooled to room temperature and purified water was added, causing the precipitation of a product. The precipitate was filtered out, washed with methanol, and dried under reduced pressure to give a compound (3a) (yellow powder ) . The product weight was 1.88 g, and the yield was 82%. [0091] <Synthesis of compound (4a) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (3a) (400 mg, 0.27 mmol), potassium carbonate (187 mg, 1.35 mmol) and the compound (2a) (280 mg, 1.06 mmol), and was purged with nitrogen. Further, mesitylene (6 ml) and silver (I) trifluoromethanesulfonate (171 mg, 0.67 mmol) were added. The mixture was stirred under reflux for 4 hours. After the reaction completed, the reaction liquid was cooled to room temperature and chloroform was added. The mixture was filtered through Celite to remove insoluble matters. The filtrate was distilled to remove the solvent. The residue was
purified by silica gel column chromatography (eluting solution: chloroform/hexane = 1/1) , then recrystallized from methanol/dichloromethane, and dried under vacuum to give a compound (4a) (yellow fine crystal) . The product weight was 400 mg, and the yield was 76%. The product was analyzed by 1H-NMR, but no peaks assigned to meridional complexes were observed. This result indicated that the compound was 100% facial .
1H-NMR (270 MHz, CDCl3) ppm: 7.78 (m, 3H, ArH), 7.28 (d, 3H, J = 6.2 Hz, ArH) , 6.49 (dd, 3H, J = 6.5, 2.4 Hz, ArH) , 6.36 (m, 3H, ArH), 6.26 (dd, 3H, J = 9.2, 2.7 Hz, ArH), 3.93 (d, 6H, J = 5.7 Hz, CH2O), 1.74 (m, IH, CH), 1.51-1.31 (m, 24H, CH2), 0.96-0.87 (m, 18H, CH3). [Synthetic Example 2] (Synthesis of iridium complex compound (4b) )
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the
2-chloro-4-hydroxypyridine from Synthetic Example 1 (1.3O g, 10 mmol) and potassium carbonate (2.76 g, 20 mmol) , and was purged with nitrogen. Dehydrated DMF (20 ml) and
2-bromobutane (2.06 g, 15 mmol) were added, and the mixture was stirred at 800C for 14 hours. After the reaction completed, chloroform was added and the reaction liquid was washed with purified water two times . The organic phase was extracted with
ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, and distilled to remove the solvent. The residue was purified by medium pressure silica gel column chromatography (eluting solution: gradually changed from chloroform/hexane = 1/1 to chloroform) , then distilled to remove the solvent, and dried under reduced pressure to give a compound (Ib) (colorless liquid) . The product weight was 1.85 g, and the yield was 100%. [0092] 1H-NMR (270 MHz, CDCl3) ppm: 8.16 (d, IH, J= 5.9 Hz, ArH) , 6.80 (d, IH, J = 2.4 Hz, ArH), 6.71 (dd, IH, J = 5.8, 2.0 Hz, ArH), 4.38 (m, IH, CH), 1.71 (m, 2H, CH2), 1.33 (d, 3H, J = 6.5 Hz, CH3), 0.97 (t, 3H, J = 7.4 Hz, CH3). <Synthesis of compound (2b) > A three-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (Ib) (1.85 g, 10 mmol) , 2, 4-difluorophenylboronic acid (1.9Og, 12 mmol) , sodium carbonate (2.12 g, 20 mmol), 1, 2-dimethoxyethane (30 ml) and purified water (10 ml) . Nitrogen was bubbled through the liquid for 5 minutes. Further,
[1, 1' -bis (diphenylphosphino) ferrocene] dichloropalladium (II) dichloromethane complex (163 mg, 0.2 mmol) was added. The mixture was stirred under reflux for 3 hours. After the reaction completed, the reaction liquid was cooled to room
temperature and purified water was added. The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, and distilled to remove the solvent. The residue was purified by medium pressure silica gel column chromatography (eluting solution: gradually changed from chloroform/hexane = 1/1 through chloroform to ethyl acetate/chloroform = 2.5/97.5), then distilled to remove the solvent, and dried under reduced pressure to give a compound (2b) (colorless liquid) . The product weight was 2.10 g, and the yield was 80%. [0093]
1H-NMR (270 MHz, CDCl3) ppm: 8.48 (d, IH, J = 5.7 Hz, ArH) , 7.97 (m, IH, ArH), 7.24 (m, IH, ArH), 6.99 (m, IH, ArH), 6.90 (m, IH, ArH), 6.75 (dd, IH, J = 5.8, 2.6 Hz, ArH), 4.45 (m, IH, CH) , 1.74 (m, IH, CH2) , 1.35 (d, 3H, J = 5.9 Hz, CH3) , 0.99 (t, 3H, J = 7.2 Hz, CH3) . <Synthesis of compound (3b) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (2b) (885 mg, 3.4mmol), iridium (III) chloride trihydrate (494 mg, 1.4mmol), 2-ethoxyethanol (21 ml) and purified water (7 ml) . Nitrogen was bubbled through the liquid, and thereafter the mixture was stirred under reflux for 69 hours. After the reaction completed, the reaction liquid was cooled to room temperature
and purified water was added, causing the precipitation of a product. The precipitate was filtered out, washed with methanol, and dried under reduced pressure to give a compound (3b) (yellow powder ) . The product weight was 733 mg, and the yield was 70%. [0094] <Synthesis of compound (4b) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (3b) (301 mg, 0.2 mmol) , potassium carbonate (138 mg, 1.0 mmol) and the compound (2b) (132 mg, 0.5 mmol), and was purged with nitrogen. Further, mesitylene (4 ml) and silver (I) trifluoromethanesulfonate (123 mg, 0.48 mmol) were added. The mixture was stirred under reflux for 4 hours. After the reaction completed, the reaction liquid was cooled to room temperature and chloroform was added. The mixture was filtered through Celite to remove insoluble matters. The filtrate was distilled to remove the solvent. The residue was purified by silica gel column chromatography (eluting solution: gradually changed from chloroform/hexane = 1/3 to chloroform) , then recrystallized from methanol/dichloromethane, and dried under vacuum to give a compound (4b) (yellow fine crystal) . The product weight was 332 mg, and the yield was 85%. The product was analyzed by
1H-NMR, but no peaks assigned to meridional complexes were observed. This result indicated that the compound was 100% facial .
1H-NMR (270 MHz, CDCl3) ppm: 7.76 (m, 3H, ArH), 7.27 (d, 3H, J = 6.8 Hz, ArH) , 6.46 (dd, 3H, J = 6.3, 2.3 Hz, ArH) , 6.36
(m, 3H, ArH), 6.26 (m, 3H, ArH), 4.41 (m, 3H, CH), 1.72 (m,
3H, CH2), 1.34 (d, 9H, J = 5.7 Hz, CH3), 0.98 (t, 9H, J = 7.0
Hz, CH3) .
[Synthetic Example 3] <Synthesis of compound (Ic) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the
2-chloro-4-hydroxypyridine from Synthetic Example 1 (2.34 g, 18.1 mmol) and potassium carbonate (5.00 g, 36.2 mmol) , and was purged with nitrogen. Dehydrated DMF (72 ml) and
2-ethylhexyl bromide (5.24 g, 27.15 mmol) were added, and the mixture was stirred at 800C for 5 hours. After the reaction completed, toluene was added and the reaction liquid was washed with purified water two times . The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, and distilled to remove the solvent. The residue was purified by medium pressure silica gel column chromatography (eluting solution: gradually changed from chloroform to ethyl acetate/chloroform = 2/8),
then distilled to remove the solvent, and dried under reduced pressure to give a compound (Ic) (colorless liquid) . The product weight was 2.12 g, and the yield was 48%. [0095] 1H-NMR (270 MHz, CDCl3) ppm: 8.17 (d, IH, J = 5.9 Hz, ArH) , 6.83 (d, IH, J = 2.2 Hz, ArH), 6.74 (dd, IH, J = 5.9, 2.4 Hz, ArH), 3.89 (d, 2H, J=5.7Hz, CH2O), 1.74 (m, IH, CH), 1.54-1.31 (m, 8H, CH2), 0.96-0.88 (m, 6H, CH3). <Synthesis of compound (2c) > A three-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (Ic) (2.12 g, 8.77 mmol) , 2, 4-difluorophenylboronic acid (1.66 g, 10.52 mmol) , sodium carbonate (1.86 g, 17.54 mmol), 1,2-dimethoxyethane (27 ml) and purified water (9 ml). Nitrogen was bubbled through the liquid for 5 minutes . Further, [1,1' -bis (diphenylphosphino) ferrocene] dichloropalladium (II) dichloromethane complex (163 mg, 0.2 mmol) was added. The mixture was stirred under reflux for 2 hours. After the reaction completed, the reaction liquid was cooled to room temperature and purified water was added. The organic phase was extracted with ethyl acetate. The organic phase was then dried over magnesium sulfate, filtered, and distilled to remove the solvent. The residue was purified by medium pressure silica gel column chromatography (eluting solution:
gradually changed from ethyl acetate/hexane = 5/95 to ethyl acetate/hexane = 30/70) , then distilled to remove the solvent, and dried under reduced pressure to give a compound (2c) (colorless liquid). The product weight was 2.17 g, and the yield was 78%. [0096]
1H-NMR (270 MHz, CDCl3) ppm: 8.50 (d, IH, J= 5.9 Hz, ArH) , 7.97 (m, IH, ArH), 7.25 (d, IH, ArH), 6.98 (m, IH, ArH), 6.90 (m, IH, ArH), 6.79 (dd, IH, J = 5.7, 2.4 Hz, ArH), 3.94 (d, 2H, J =5.9 Hz, CH2O), 1.77 (m, IH, CH), 1.55-1.32 (m, 8H, CH2), 0.97-0.88 (m, 6H, CH3) . <Synthesis of compound (3c) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (2c) (767 mg, 2.4mmol), iridium (III) chloride trihydrate (353 mg, l.Ommol), 2-ethoxyethanol (15 ml) and purified water (5 ml) . Nitrogen was bubbled through the liquid, and thereafter the mixture was stirred under reflux for 23 hours. After the reaction completed, the reaction liquid was cooled to room temperature and purified water was added, causing the precipitation of a product. The precipitate was filtered out, washed with methanol, and dried under reduced pressure to give a compound (3c) (yellow powder ) . The product weight was 736 mg, and the yield was 85%.
[ 0097 ]
<Synthesis of compound (4c) >
A two-necked flask equipped with a Dimroth condenser and a three-way cock was charged with the compound (3c) (346 mg, 0.2 mmol) , potassium carbonate (138 mg, 1.0 mmol) and the compound (2c) (160 mg, 0.5 mmol), and was purged with nitrogen. Further, mesitylene (4 ml) and silver (I) trifluoromethanesulfonate (123 mg, 0.48 mmol) were added. The mixture was stirred under reflux for 3 hours. After the reaction completed, the reaction liquid was cooled to room temperature and chloroform was added. The mixture was filtered through Celite to remove insoluble matters. The filtrate was distilled to remove the solvent. The residue was purified by silica gel column chromatography (eluting solution: gradually changed from chloroform/hexane = 5/95 to chloroform/hexane = 20/80) , then recrystallized from methanol/dichloromethane, and dried under vacuum to give a compound (4c) (yellow fine crystal) . The product weight was 394 mg, and the yield was 86%. The product was analyzed by 1H-NMR, but no peaks assigned to meridional complexes were observed. This result indicated that the compound was 100% facial .
1H-NMR (270 MHz, CDCl3) ppm: 7.78 (m, 3H, ArH), 7.28 (d, 3H, J = 6.2 Hz, ArH) , 6.49 (dd, 3H, J = 6.5, 2.4 Hz, ArH) , 6.36
(m, 3H, ArH), 6.26 (dd, 3H, J = 9.2, 2.7 Hz, ArH), 3.93 (d, 6H, J = 5.7 Hz, CH2O), 1.74 (m, IH, CH), 1.51-1.31 (m, 24H, CH2), 0.96-0.87 (m, 18H, CH3). <Solubility test> [Example 1]
The compound (4a) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred at room temperature for 1 hour. Whether the compound (4a) completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0098] [Example 2]
The compound (4b) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred at room temperature for 1 hour. Whether the compound (4b) completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0099]
[Example 3]
The compound (4c) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred at room temperature for 1 hour.
Whether the compound (4c) completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0100] [Comparative Example 1]
Ir (F2MeOpPy) 3 (a facial complex illustrated below) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred at room temperature for 1 hour. Whether the Ir(F2MeOpPy)3 completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0101] [Comparative Example 2]
Ir (F2HexOppy) 2 (pic) (illustrated below) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred at room temperature for 1 hour. Whether the Ir (F2HexOppy) 2 (pic) completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0102]
[Comparative Example 3]
Ir(ppy)3 (a facial complex illustrated below) was mixed with chloroform or toluene so that a predetermined concentration would be obtained, and the mixture was stirred
at room temperature for 1 hour. Whether the Ir(ppy)3 completely dissolved or partly remained undissolved was visually inspected. The result is shown in Table 1. [0103]
Ir(F2MeOpPy)3 Ir(F2HeXOPPy)2(PiC)
[0104]
Table 1
AA: Completely dissolved BB: Partly undissolved [0105]
The results in Table 1 show that the blue-emitting iridium complex compounds (4a) , (4b) and (4c) of the present invention have higher solubility in organic solvents as compared with conventional blue-emitting iridium complex
compound Ir (F2Me0ppy) 3 and conventional green-emitting iridium complex Ir (ppy) 3. Conventional blue-emitting iridium complex compound Ir(F2HeXOpPy)2(PiC) also proved high solubility in organic solvents. [0106]
[Example 4]
<Production of organic EL device>
An organic EL device was produced with use of an ITO (indium tin oxide) glass substrate (manufactured by Nippo Electric Co. , Ltd. ) which was composed of a 25 mm square glass substrate and in which two stripe ITO electrodes having a width of 4 mm were formed as anodes on one surface. [0107]
First, the ITO (anodes) of the ITO substrate was spin coated with poly (3, 4-ethylenedioxythiophene) polystyrenesulfonic acid (trade name "Baytron P", manufactured by Bayer AG) at 3500 rpm for a coating time of 40 seconds. The coating was dried at 60° C for 2 hours under reduced pressure in a vacuum drying machine to form anode buffer layers. The anode buffer layers had a thickness of about 50 nm. [0108]
Next, a coating solution for forming a luminescent layer was prepared. Specifically, 15 mg of the compound (4a) from
Synthetic Example 1 and 135 mg of poly (N-vinylcarbazole) were dissolved in 9850 mg of chloroform (special grade, manufactured by Wako Pure Chemical Industries, Ltd.). The solution obtained was filtered through a 0.2 μm filter to give a coating solution. The coating solution was applied on the anode buffer layers by a spin coating method at 3000 rpm for a coating time of 30 seconds. The coating was dried at room temperature (25 "C) for 30 minutes, whereby luminescent layers were formed. The luminescent layers had a thickness of about 100 nm. Next, the substrate with the luminescent layers was placed in a vapor deposition apparatus. Barium was deposited in a thickness of 5 nm at a deposition rate of 0.01 nm/sec. Subsequently, aluminum was deposited as cathodes in a thickness of 150 nm at a deposition rate of 1 nm/sec. Consequently, an organic EL device 1 was manufactured. The barium/aluminum layers formed two stripes having a width of 3 mm which were orthogonal to the extending direction of the anodes. Thus, four organic light-emitting elements 4 mm in length and 3 mm in width were prepared on the glass substrate. [0109]
<Evaluation of electroluminescent characteristics>
The organic EL device was energized to emit light by means of programmable direct-current voltage/current source TR6143 manufactured by ADVANTEST CORPORATION. The luminance was
measured with brightness meter BM-8 manufactured by TOPCON CORPORATION. Table 2 shows the luminescent color, emission uniformity, external quantum efficiency at 100 cd/m2, and luminance half period at a constant current relative to the initial luminance of 100 cd/m2 (the values of the external quantum efficiency and the luminance half period are averages of the four light-emitting elements on the substrate) . The luminance half period in Table 2 is expressed relative to the measured value (100) of an organic EL device 4 described later. [0110]
[Example 5]
An organic EL device 2 was prepared and evaluated in the same manner as in Example 4, except that the compound (4a) was changed to the compound (4b) . The results are shown in Table 2.
[0111] [Example 6]
An organic EL device 3 was prepared and evaluated in the same manner as in Example 4, except that the compound (4a) was changed to the compound (4c) . The results are shown in Table 2.
[0112] [Comparative Example 4]
An organic EL device 4 was prepared and evaluated in the
same manner as in Example 4, except that the compound (4a) was changed to Ir(F2MeOpPy)3. The results are shown in Table 2. [0113]
[Comparative Example 5] An organic EL device 5 was prepared and evaluated in the same manner as in Example 4, except that the compound (4a) was changed to Ir (F2HexOppy) 2 (pic) . The results are shown in Table 2.
[0114] [Reference Example 1]
An organic EL device 6 was prepared and evaluated in the same manner as in Example 4, except that the compound (4a) was changed to Ir(ppy)3. The results are shown in Table 2. [0115]
Table 2
CP
[ 0116 ]
As shown in Table 2, the organic EL device (Comparative Example 4) in which the luminescent layer contained the conventional blue-emitting iridium complex compound Ir (F2Me0ppy) 3 did not emit light uniformly due to the association and aggregation of the luminescent iridium complex compound. In contrast, the organic EL devices (Examples 4 to 6) in which the luminescent layer contained the iridium complex compound of the present invention emitted light uniformly. [0117]
Further, the organic EL device (Comparative Example 5) in which the luminescent layer contained the conventional blue-emitting iridium complex compound Ir (F2HexOppy) 2 (pic) had a short luminance half period because of easy decomposition of the compound. In contrast, the organic EL devices (Examples 4 to 6) in which the luminescent layer contained the iridium complex compound of the present invention had improved external quantum efficiency and luminance half period, and were equal or superior in these properties to the organic EL device (Reference Example 1) using the conventional green-emitting iridium complex.
Claims
1. An iridium complex compound represented by Formula 'I) below:
R2 to R4 are each independently a hydrogen atom or a Cl-IO alkyl group;
R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, Cl-IO fluorine-substituted alkyl groups, Cl-IO fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-IO aminocarbonyl groups, thiocyanate group and Cl-IO sulfonyl groups, a Cl-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom; and at least one of R to R is the electron-withdrawing group.
2. The iridium complex compound according to claim 1, wherein the electron-withdrawing group is a fluorine atom, a Cl-IO fluorine-substituted alkyl group, a Cl-10 fluorine-substituted alkoxy group or a cyano group.
3. The iridium complex compound according to claims 1 or 2, which is represented by Formula (2) below:
wherein R1 is a C2-30 organic group; and R2 to R4 are each a hydrogen atom or a Cl-10 alkyl group.
4. The iridium complex compound according to any one of claims 1 to 3, which is represented by Formula (3) below:
5. The iridium complex compound according to any one of claims 1 to 4, wherein R1 is a C2-30 alkyl group or a C7-30 aralkyl group.
6. The iridium complex compound according to any one of claims 1 to 5, which is a facial complex.
7. An organic electroluminescent device comprising a substrate, a pair of electrodes formed on the substrate, and one or plural organic layers including a luminescent layer which are formed between the pair of the electrodes, wherein the luminescent layer comprises the iridium complex compound according to any one of claims 1 to 6.
8. The organic electroluminescent device according to claim 7, wherein the luminescent layer contains a charge-transporting non-conjugated polymer compound.
9. An image display device prepared using the organic electroluminescent device according to claim 7 or 8.
10. A plane light source prepared using the organic electroluminescent device according to claim 7 or 8.
11. A process for producing the iridium complex compound according to claim 1 which comprises reacting iridium (III) chloride trihydrate and a phenylpyridine derivative represented by Formula (1-1) below in an alcohol/water mixed solvent with heating to obtain a binuclear iridium complex represented by Formula (1-2) below, and reacting the binuclear complex and a phenylpyridine derivative represented by Formula (1-1) in a solvent in the presence of a silver salt and/or a base with heating;
(1-2)
in Formulae (1-1) and (1-2), R1 is a C2-30 organic group;
R2 to R4 are each independently a hydrogen atom or a Cl-IO alkyl group;
R5 to R8 are each independently an electron-withdrawing group selected from the group consisting of halogen atoms, Cl-IO fluorine-substituted alkyl groups, Cl-IO fluorine-substituted alkoxy groups, cyano group, aldehyde group, C2-10 acyl groups, C2-10 alkoxycarbonyl groups, Cl-10 aminocarbonyl groups, thiocyanate group and Cl-IO sulfonyl groups, a Cl-10 organic group optionally having a heteroatom (except the electron-withdrawing groups) or a hydrogen atom; and at least one of R5 to R8 is the electron-withdrawing group.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007188259A JP2009023938A (en) | 2007-07-19 | 2007-07-19 | Iridium complex compound, organic electroluminescent device and use thereof |
| JP2007-188259 | 2007-07-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2009011447A2 true WO2009011447A2 (en) | 2009-01-22 |
| WO2009011447A3 WO2009011447A3 (en) | 2009-03-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/JP2008/063219 WO2009011447A2 (en) | 2007-07-19 | 2008-07-16 | Iridium complex compounds, organic electroluminescent devices and uses thereof |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2009023938A (en) |
| TW (1) | TW200922941A (en) |
| WO (1) | WO2009011447A2 (en) |
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| WO2013018531A1 (en) * | 2011-07-29 | 2013-02-07 | Canon Kabushiki Kaisha | Organometallic complex and organic light emitting element including the same |
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| WO2017122516A1 (en) * | 2016-01-14 | 2017-07-20 | 国立研究開発法人産業技術総合研究所 | Method for producing cyclometallated iridium complex |
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| KR20210111760A (en) | 2018-12-28 | 2021-09-13 | 가부시키가이샤 한도오따이 에네루기 켄큐쇼 | Organic compounds, light emitting devices, light emitting devices, electronic devices, and lighting devices |
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Also Published As
| Publication number | Publication date |
|---|---|
| JP2009023938A (en) | 2009-02-05 |
| TW200922941A (en) | 2009-06-01 |
| WO2009011447A3 (en) | 2009-03-26 |
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