Patent Application
20220336752
The present invention relates to an organic electroluminescent element, a material for an organic electroluminescent element, alight emitting device, a display device, and an illumination device each using the element, and a compound used in the element.
Since organic electroluminescent elements (which may hereinafter also be referred to as “elements” or “organic EL elements”) are capable of high-luminance light emitting with driving at a low voltage, they have been actively researched and developed. The organic electroluminescent elements have organic layers between a pair of electrodes, and utilize, for light emitting, energy of an exciton generated as a result of recombination of electrons injected from a cathode and holes injected from an anode in the organic layer.
In recent years, by using phosphorescent light emitting materials, the efficiency of organic electroluminescent elements is being enhanced. For practical use, however, improvements are required in terms of reduction in driving voltage, durability, and the like.
Meanwhile, an organic electroluminescent element which uses, as a host material of the light emitting layer, a compound having a structure obtained from triphenylamine by allowing the phenyl groups therein to be connected to each other to undergo ring fusion, and thus, form a carbazole ring, has been known.
PTL 1 describes an organic electroluminescent element, which uses a compound of a structure obtained from triphenylamine by allowing two or three phenyl groups therein to be connected to each other to undergo ring fusion as a host material of the light emitting layer, and is combined with a phosphorescent light emitting material. Further, it can be seen from Examples in this document that the element is excellent in driving voltage and luminous efficiency.
On the other hand, PTL 2 describes a polycyclic fused compound further having a fused ring in a carbazole ring, and also describes that the compound is used in an organic electroluminescent element. However, the document does not describe a compound of a fused structure obtained from triphenylamine by allowing two or more phenyl groups therein to be connected to each other to undergo ring fusion.
PTL 3 describes a compound of a fused structure obtained from triphenylamine by allowing two phenyl groups therein to be connected to each other to undergo ring fusion, and also describes that an organic electroluminescent element having good luminous efficiency and low driving voltage can be provided by using the compound as a host material of a light emitting layer.
[PTL 1] WO2011/042107
[PTL 2] WO2010/131855
[PTL 3] JP-A-2010-087496
In view of the above description, the present inventors have conducted studies on the characteristics of the organic electroluminescent elements described in PTLs 1 to 3, and as a result, they have found that the elements of the PTLs 1 to 3 were not satisfactory in the reduction in driving voltage and also not satisfactory in durability.
It is an object of the present invention to provide an organic electroluminescent element which has low driving voltage and excellent durability by solving the aforementioned problems.
The present inventors have conducted extensive investigations, and as a result, they have found that an organic electroluminescent element having low driving voltage and excellent durability is provided by using a compound obtained by allowing aryl groups or heteroaryl groups of two 6-membered rings of an amine tri-substituted with aryl groups or heteroaryl groups of a 6-membered ring to be connected to each other to undergo ring fusion, and having aryl groups or heteroaryl groups as a substituent, in which the substituents are fused at a specific position.
That is, the present invention which is a specific means for solving the problem described above is as follows.
[1] An organic electroluminescent element including a substrate, a pair of electrodes including an anode and a cathode, disposed on the substrate, and at least one organic layer including a light emitting layer, disposed between the electrodes,
in which at least one layer of the organic layer(s) contains a compound represented by the following general formula (1).
General Formula (1)
(In the general formula (1), X1 to X11 each independently represent CR0 or N, and R0s each independently represent a hydrogen atom or a substituent. Adjacent two of X1 to X11 each independently represent at least CR0, R0s of the adjacent two CR0s are bonded to each other to form a ring, and only one R0 of the adjacent two CR0s represents an aryl group or a heteroaryl group. However, in the case where X7 and X8 each independently represent CR0, R0 contained in X7 and R0 contained in X8 are not bonded to each other to form a ring.)
[2] In the organic electroluminescent element as described in [1], in the general formula (1), one R0 of the adjacent two CR0s, in which R0s are bonded to each other to forma ring, preferably represents an aryl group or a heteroaryl group of a 6-membered ring.
[3] In the organic electroluminescent element as described in [1] or [2], the compound represented by the general formula (1) is preferably a compound represented by any one of the following general Formulae (2) to (9).
(In the general formulae (2) to (9), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, R1 to R3 each independently represent a substituent, XA1 to XA15, XB1 to XB15, XC1 to XC15, XD1 to XD15, XE1 to XE15, XF1 to XF15, XG1 to XG15 and XH1 to XH15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent.)
[4] In the organic electroluminescent element as described in [1] or [2], the compound represented by the general formula (1) is preferably a compound represented by any one of the following general formulae (10) to (17).
(In the general formulae (10) to (17), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. RA1 to RA15, RB1 to RB15, RC1 to RC15 to RD1 to RD15, RE1 to RE15, RF1 to RF15, RG1 to RG15 and RH1 to RH15 each independently represent a hydrogen atom or a substituent.)
[5] In the organic electroluminescent element as described in any one of [1] to [4], the value of LUMO of the compound represented by the general formula (1), as determined by an electron density functional theory (B3LYP/6-31G (d) level), is preferably more than 1.25.
[6] In the organic electroluminescent element as described in any one of [1] to [5], the compound represented by the general formula (1) preferably has a substituent containing at least one of a pyridine ring, a pyrimidine ring, a triazine ring, a cyano group, and a carbonyl group.
[7] In the organic electroluminescent element as described in any one of [1] to [6], the light emitting layer preferably contains at least one kind of phosphorescent light emitting material.
[8] In the organic electroluminescent element as described in any one of [1] to [6], the phosphorescent light emitting material is preferably an iridium complex represented by the following general formula (E-1).
(In the general formula (E-1), Z1 and Z2 each independently represent a carbon atom or a nitrogen atom.
A1 represents an atomic group that forms a 5- or 6-membered hetero ring together with Z1 and a nitrogen atom.
B1 represents an atomic group that forms a 5- or 6-membered ring together with Z2 and a carbon atom.
(X—Y) represents a mono-anionic bidentate ligand.
nE1 represents an integer of 1 to 3.)
[9] In the organic electroluminescent element as described in [8], the iridium complex represented by the general formula (E-1) is preferably represented by the following general formula (E-2).
(In the general formula (E-2), AE1 to AE8 each independently represents a nitrogen atom or C—RE.
RE represents a hydrogen atom or a substituent.
(X—Y) represents a mono-anionic bidentate ligand.
nE2 represents an integer of 1 to 3.)
[10] In the organic electroluminescent element as described in any one of [1] to [9], the light emitting layer preferably contains the compound as described in any one of [1] to [6].
[11] A light emitting device using the organic electroluminescent element as described in any one of [1] to [10].
[12] A display device using the organic electroluminescent element as described in any one of [1] to [10].
[13] An illumination device using the organic electroluminescent element as described in any ore of [1] to [10].
[14] A compound represented by the following general formula (1).
(In the general formula (1), X1 to X11 each independently represent CR0 or N, and R0s each independently represent a hydrogen atom or a substituent. Adjacent two of X1 to X11 each independently represent at least CR0, R0s of the adjacent two CR0s are bonded to each other to form a ring, and only one R0 of the adjacent two CR0s represents an aryl group or a heteroaryl group. However, in the case where X7 and X8 each independently represent CR0, R0 contained in X7 and R0 contained in X8 are not bonded to each other to form a ring.)
[15] The compound as described in [14] is preferably represented by any one of the following general formulae (2) to (9).
(In the general formulae (2) to (9), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. XA1 to XA15, XB1 to XB15, XC1 to XC15, XD1 to XD15, XE1 to XE15, XF1 to XF15, XG1 to XG15 and XH1 to XH15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent.)
[16] The compound as described in [14] or [15] is preferably represented by anyone of the following general formulae (10) to (17).
(In the general formulae (10) to (17), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. RA1 to RA15, RB1 to RB15, RC1 to RC15, RD1 to RD15, RE1 to RE15, RF1 to RF15, RG1 to RG15 and RH1 to RH15 each independently represent a hydrogen atom or a substituent.)
[17] A material for an organic electroluminescent element, represented by the following general formula (1).
(In the general formula (1), X1 to X11 each independently represent CR0 or N, and R0s each independently represent a hydrogen atom or a substituent. Adjacent two of X1 to X11 each independently represent at least CR0, R0 s of the adjacent two CR0s are bonded to each other to form a ring, and only one R0 of the adjacent two CR0s represents an aryl group or a heteroaryl group. However, in the case where X7 and X8 each independently represent CR0, R0 contained in X7 and R0 contained in X8 are not bonded to each other to form a ring.)
[18] The material for an organic electroluminescent element as described in [17] is preferably represented by any one of the following general formulae (2) to (9).
(In the general formulae (2) to (9), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. XA1 to XA15, XB1 to XB15, XC1 to XC15, XD1 to XD15, XE1 to XE15, XF1 to XF15, XG1 to XG15 and XH1 to XH15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent.)
[19] The material for an organic electroluminescent element as described in [17] or [18] is preferably represented by any one of the following general formulae (10) to (17).
(In the general formula (10) to (17), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. RA1 to RA15, RB1 to RB15, RC1 to RC15, RD1 to RD15, RE1 to RE15, RF1 to RF15, RG1 to RG15 and RH1 to RH15 each independently represent a hydrogen atom or a substituent.)
According to the present invention, an organic electroluminescent element having low driving voltage and excellent durability can be provided.
In addition, according to the present invention, a light emitting device, a display device, and an illumination device each using the organic electroluminescent element can also be provided.
Hereinbelow, the details of the present invention will be described. The description of the configuration requirements as described below may be based on representative embodiments of the present invention, but the present invention is not limited to these embodiments. Incidentally, in the present specification, the range expressed with “to” means a range including the numerical values before and after “to” as the lower limit and the upper limit, respectively.
[Organic Electroluminescent Element, Compound, and Material for Organic Electroluminescent Element]
The compound of the present invention and the material for an organic electroluminescent element of the present invention may be represented by the general formula (1).
The organic electroluminescent element of the present invention may include a substrate, a pair of electrodes including an anode and a cathode, disposed on the substrate, and at least one organic layer including a light emitting layer, disposed between the electrodes, in which at least one layer of the organic layer(s) may contain the compound represented by the general formula (1).
The configuration of the organic electroluminescent element of the present invention is not particularly limited.
The element configuration, and the substrate, the anode, and the cathode of the organic: electroluminescent element are described in detail, for example, in JP-A-2008-270736, and the matters described in the patent publication can be applied to the present invention.
Hereinafter, preferred embodiments of the organic electroluminescent element of the present invention will be described, in the order of the substrate, the electrode, the organic layer, the protective layer, the sealing enclosure, the driving method, the light emitting wavelength, and applications thereof.
<Substrate>
The organic electroluminescent element of the present invention has a substrate.
The substrate used in the present invention is preferably a substrate that does not scatter or decay light emitted from the organic layer. In the case of an organic material, those having excellent heat resistance, dimensional stability, solvent resistance, electrical insulating properties, and processability are preferred.
<Electrodes>
The organic electroluminescent element of the present invention has a pair of electrodes including an anode and a cathode, disposed on the substrate.
In view of the properties of the light emitting element, at least one electrode of a pair of electrodes, the anode and the cathode, is preferably transparent or semi-transparent.
(Anode)
The anode may be typically one having a function as an electrode of supplying holes into an organic layer, and is not particularly limited in its shape, structure, size, or the like. Further, depending on the use and purpose of the light emitting element, the anode can be suitably selected from the known electrode materials. As described above, the anode is usually provided as a transparent anode.
(Cathode)
The cathode may be typically one having a function as an electrode of injecting electrons to an organic layer, and is not particularly limited in its shape, structure, size, or the like. Further, depending on the use and purpose of the light emitting element, the cathode can be suitably selected from the known electrode materials.
<Organic Layer>
The organic electroluminescent element of the present invention includes organic layers disposed between the electrodes, in which the organic layer(s) contains the compound represented by the general formula (1).
The organic layer is not particularly limited and can be suitably selected depending on the use and purpose of the organic electroluminescent element. However, the organic layer is preferably formed on the transparent electrode or the semi-transparent electrode. In that case, the organic layer is formed on the whole surface or one surface of the transparent electrode or the semi-transparent electrode.
The shape, the size, the thickness, and the like of the organic layer are not particularly limited and can be suitably selected depending on the purpose.
Hereinafter, the configuration of the organic layer, the method for forming an organic layer, preferred aspects of the respective layers constituting the organic layer, and the materials used in the respective layers in the organic electroluminescent element of the present invention will be described in detail in order.
(Configuration of Organic Layers)
In the organic electroluminescent element of the present invention, the organic layers preferably include a charge transporting layer. The charge transporting layer means a layer, in which charge transfer occurs when a voltage is applied to the organic electroluminescent element. Specific examples of the charge transporting layer include a hole injecting layer, a hole transporting layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transporting layer, and an electron injecting layer.
The organic electroluminescent element of the present invention includes a light emitting layer containing a phosphorescent light emitting material and other organic layers, the light emitting layer preferably containing a compound represented by the general formula (1). Here, the place where the compound represented by the general formula (1) is included is not particularly limited, but the light emitting layer preferably contains the compound represented by the general formula (1). Here, the compound represented by the general formula (1) is preferably used as a host compound of the light emitting layer. In addition, in the organic electroluminescent element of the present invention, the organic layers preferably include a light emitting layer containing the phosphorescent light emitting material and other organic layers. In the organic electroluminescent element of the present invention, however, even when the organic layers include a light emitting layer and other organic layers, the layers are not required to be clearly distinguished from one another.
Furthermore, preferably the organic electroluminescent element of the present invention has an electron transporting layer adjacent to the cathode between the pair of electrodes, optionally has an hole blocking layer adjacent to the cathode of the electron transporting layer, and the electron transporting layer or the hole blocking layer preferably contains the compound represented by the general formula (1).
Each of these organic layers may include a plurality of layers, and in the case of providing a plurality of layers, the layers may be formed from the same material or may be formed from different materials for respective layers.
(Method for Forming Organic Layer)
The respective organic layers in the organic electroluminescent element of the present invention can be suitably formed by any of dry film forming methods such as a deposition method and a sputtering method, and wet type film formation methods (solution coating methods) such as a transfer method, a printing method, a spin coating method, and a bar coating method.
In the organic electroluminescent element of the present invention, the organic layer disposed on the pair of electrodes preferably includes at least a layer formed by the deposition of a composition further including the compound represented by the general formula (1).
(Light Emitting Layer)
The light emitting layer is a layer having a function of, upon application of an electric field, receiving holes from the anode, the hole injecting layer or the hole transporting layer, receiving electrons from the cathode, the electron injecting layer or the electron transporting layer, providing a recombination site of the holes and the electrons, and thereby causing light emitting. However, the light emitting layer in the present invention is not necessarily limited to the light emitting by such a mechanism. The light emitting layer in the organic electroluminescent element of the present invention preferably contains at least one kind of phosphorescent light emitting material.
The light emitting layer in the organic electroluminescent element of the present invention may be constituted of only the phosphorescent light emitting material, or may be constituted as a mixed layer of a host material and the phosphorescent light emitting material. One kind or two or more kinds of phosphorescent light emitting materials may be used. The host material is preferably a charge transporting material. One kind or two or more kinds of materials may be used as the host material. Examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. In addition, the light emitting layer may contain a material which does not have charge transporting property and does not emit light.
In addition, the light emitting layer may be made of a single layer or multiple layers including two or more layers. The layers may include the same light emitting material or host material, or also may include different materials for the respective layers. In the case where a plurality of light emitting layers are present, the light emitting layers may emit light in different luminous colors from one another.
The thickness of the light emitting layer is not particularly limited, but it is usually from 2 nm to 500 nm, and above all, from the viewpoint of external quantum efficiency, it is more preferably from 3 nm to 200 nm, and still more preferably from 5 nm to 100 nm.
In the organic electroluminescent element of the present invention, in a preferred embodiment, the light emitting layer preferably contains a compound represented by the general formula (1), and in a more preferred embodiment, the compound represented by the general formula (1) is used as a host material of the light emitting layer. Here, the host material as referred to in the present specification is a compound which chiefly plays a role in injecting or transporting charges in the light emitting layer and is also a compound which does not substantially emit light in itself. As used herein, it is meant by the terms “which does not substantially emit light” that the amount of light emission from the compound which does not substantially emit light is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less, with respect to the total amount of light emission in the whole of the element.
Hereinafter, as the materials of the light emitting layer, the compound represented by the general formula (1), the phosphorescent light emitting material, and host materials other than the compound represented by the general formula (1) will be described in this order. Further, the compound represented by the general formula (1) may be used as a material other than the light emitting layer in the organic electroluminescent element of the present invention.
(1) Compound Represented by General Formula (1)
It is reported that the phenylcarbazole described in WO2010/131855 and the like has cleavage of a bond between N of carbazole and C of a phenyl group cleaved, as a result of the analysis of decomposed products after element deterioration (J. Appl. Phys. 2007, 101, 024512). Meanwhile, a compound having an indolocarbazole skeleton represented by the following general formula (1), or a skeleton formed by substituting a specific position of a carbon atom in the indolocarbazole skeleton with a nitrogen atom can increase the durability of the obtained organic electroluminescent element. Not wishing to be restricted to any reason, the present inventors have contemplated that as suggested by the above articles, a cause of deteriorating the durability consists in the bond cleavage of the cause of deteriorating the durability, and a compound having an indolocarbazole skeleton represented by the following general formula (1), or a skeleton formed by substituting a specific position of a carbon atom in the indolocarbazole skeleton with a nitrogen atom has high durability by inhibiting the bond cleavage or promoting the rebonding after the bond cleavage.
Here, indolocarbazole compounds that have been well-known in the related art did not have an additional fused ring in indolocarbazole. Such the indolocarbazole compounds have a high ionization potential (=a high value of HOMO), and a hole injection barrier from a hole transporting layer is high, and thus, has not yet reached an element driving voltage at a level for practical use. In the present invention, by subjecting a compound having an indolocarbazole skeleton and a compound having a skeleton formed by substituting a specific position of a carbon atom in the indolocarbazole skeleton to ring fusion on a n plane, the element driving voltage can be reduced, as compared with indolocarbazole having no fused ring. Not wishing to be restricted to any reason, it is contemplated that it is possible to decrease the ionization potential (=to decrease value of HOMO), and as a result, a hole injection barrier from a hole transporting layer has been alleviated.
In addition, for the compound having an indolocarbazole skeleton described in WO2011/042107 and JP-A-2010-087496, there is a description that the indolocarbazole skeleton is further fused, but there is no exemplification of the specific compounds, and since there is a problem in the number of ring members constituting the skeleton and the positions of the fused rings, it can be seen that it is difficult to satisfy both of durability and reduction in a driving voltage.
A compound represented by the following general formula (1) will be described below.
(In the general formula (1), X1 to X11 each independently represent CR0 or N, and R0s each independently represent a hydrogen atom or a substituent. Adjacent two of X1 to X11 each independently represent at least CR0, R0s of the adjacent two CR0s are bonded to each other to forma ring, and only one R0 of the adjacent two CR0s represents an aryl group or a heteroaryl group. However, in the case where X7 and X8 each independently represent CR0, R0 contained in X7 and R0 contained in X8 are not bonded to each other to form a ring.)
Incidentally, in the present invention, the hydrogen atoms in the description of the general formula (1) include isotopes (a deuterium atom and the like), and any atoms constituting the further substituent also include the isotopes thereof.
In the present invention, when referring to a “substituent”, the substituent may be further substituted. For example, when the “alkyl group” is referred to in the present invention, it includes an alkyl group substituted with a fluorine atom (for example, a trifluoromethyl group) and an alkyl group substituted with an aryl group (for example, a triphenylmethyl group), but when “an alkyl group having 1 to 6 carbon atoms” is referred to herein, it represents any of alkyl groups having 1 to 6 carbon atoms, including the alkyl groups which are substituted.
In the general formula (1), X1 to X11 each independently represent CR0 or N, and R0s each independently represent a hydrogen atom or a substituent.
In the general formula (1), examples of the substituent represented by R0 each independently the following Substituent Group A, the substituent may have an additional substituent, and examples of the additional substituent include the groups selected from the Substituent Group A.
<<Substituent Group A>>
An alkyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 10 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, L-butyl, n-octyl, n-hexyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, and cyclohexyl), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, vinyl, allyl, 2-butenyl, and 3-pentenyl), an alkynylgroup (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, propargyl and 3-pentynyl), an aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 14 carbon atoms, for example, phenyl, p-methylphenyl, naphthyl, and anthranyl), amino group (preferably having 0 to 30 carbon atoms, more preferably having 0 to 20 carbon atoms, and particularly preferably having 0 to 10 carbon atoms, for example, amino, methylamino, dimethylamino, diethylamino, dibenzylamino, phenylamino, diphenylamino, and ditolylamino), an alkoxy group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 10 carbon atoms, for example, methoxy, ethoxy, butoxy, and 2-ethylhexyloxy), and aryloxy group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 12 carbon atoms, for example, phenyloxy, 1-naphthyloxy, and 2-naphthyloxy), a heterocyclic oxy group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy), an acyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 12 carbon atoms, for example, acetyl, benzoyl, formyl, and pivaloyl), an alkoxycarbonyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 12 carbon atoms, for example, methoxycarbonyl and ethoxycarbonyl), an aryloxycarbonyl group (preferably having 7 to 30 carbon atoms, more preferably having 7 to 20 carbon atoms, and particularly preferably having 7 to 12 carbon atoms, for example, phenyloxycarbonyl), an acyloxy group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, acetoxy and benzoyloxy), an acylamino group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, acetylamino and benzoylamino), an alkoxycarbonylamino group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 12 carbon atoms, for example, methoxycarbonylamino), an aryloxycarbonylamino group (preferably having 7 to 30 carbon atoms, more preferably having 7 to 20 carbon atoms, and particularly preferably having 7 to 12 carbon atoms, for example, phenyloxycarbonylamino), a sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, methanesulfonylamino and benzenesulfonylamino), a sulfamoyl group (preferably having 0 to 30 carbon atoms, more preferably having 0 to 20 carbon atoms, and particularly preferably having 0 to 12 carbon atoms, for example, sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and phenylsulfamoyl), a carbamoyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, and phenylcarbamoyl), an alkylthio group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, methylthio and ethylthio), an arylthio group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 12 carbon atoms, for example, phenylthio), a heterocyclic thio group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, pyridylthio, 2-benzoimizolylthio, 2-benzoxazolylthio, and 2-benzothiazolylthio), a sulfonyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, mesyl and tosyl), a sulfinyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, methanesulfinyl and benzenesulfinyl), a ureido group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, ureido, methylureido, and phenylureido), phosphoramide group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 12 carbon atoms, for example, diethylphosphoramide and phenylphosphoramide), a hydroxy group, a mercapto group, a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom), a sulfo group, a carboxyl group, a nitro group, a hydroxamic group, a sulfino group, a hydrazino group, an imino group, a heterocyclic group (inclusive of an aromatic heterocyclic group, which preferably has 1 to 30 carbon atoms, and more preferably 1 to 12 carbon atoms and in which examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and a tellurium atom, and specific examples thereof include pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl, pyrrolidino, benzoxazolyl, benzoimidazolyl, benzothiazolyl, a carbazolyl group, an azepinyl group, and a silolyl group), a silyl group (preferably having 3 to 40 carbon atoms, more preferably having 3 to 30 carbon atoms, and particularly preferably having 3 to 24 carbon atoms, for example, trimethylsilyl and triphenylsilyl), a silyloxy group (preferably having 3 to 40 carbon atoms, more preferably having 3 to 30 carbon atoms, and particularly preferably having 3 to 24 carbon atoms, for example, trimethylsilyloxy and triphenylsilyloxy), and a phosphoryl group (for example, a diphenylphosphoryl group and a dimethylphosphoryl group). These substituents may be further substituted, and examples of the additional substituent include the groups selected from the Substituent Group A as described above.
The R0s included in X1 to X11 each independently represent, among the Substituent Group A, preferably a hydrogen Lom, an aryl group, or a heteroaryl group, and more preferably a hydrogen atom or an aryl group.
The aryl group represented by R0 preferably has 6 to 30 carbon atoms, more preferably has 6 to 20 carbon atoms, and particularly preferably has 6 to 18 carbon atoms, and examples thereof include a phenyl group, a xylyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthranyl group, and a triphenylenyl group.
The heteroaryl group represented by R0 preferably has 5 to 30 ring members, more preferably has 5 to 20 ring members, and particularly preferably has 5 to 15 ring members, and examples thereof include a pyridyl group, a pyrimidyl group, a triazyl group, a pyrazyl group, a pyridazyl group, a carbazolyl group, a dibenzothiophenyl group, and a dibenzofuranyl group.
R0 contained in X1 to X11 may have an additional substituent represented by the Substituent Group A, but in the case where R0 has the additional substituent, the substituent is preferably an aryl group, or a substituent containing at least one of a pyridine ring, a pyrimidine ring, a triazine ring, a cyano group, and a carbonyl group. Above all, an unsubstituted aryl group, a pyridinyl group, a pyrimidinyl group, a triazinyl group, a cyano group-substituted aryl group, and an arylcarbonyl group-substituted aryl group are more preferred, a unsubstituted aryl group, a triazinyl group, and a cyano group-substituted aryl group are still preferable, and an unsubstituted aryl group and a cyano group-substituted aryl group are particularly preferred.
However, itis preferable that the additional substituents which may be contained in R0 be not connected to each other to form a fused ring, from the viewpoint of increasing the luminous efficiency of green phosphorescent light.
The additional substituents which may be contained in R0 may be further substituted. In the case where the additional substituents which may be contained in R0 are each a pyridinyl group, a pyrimidinyl group, or a triazinyl group, they are preferably all substituted with diaryl (preferably substituted with diphenyl).
Adjacent two of X1 to X11 each independently represent at least CR0, R0s of the adjacent two CR0s are bonded to each other to form a ring and only one R0 of the adjacent two CR0s represents an aryl group or a heteroaryl group. However, in the case where X7 and X8 each independently represent CR0, R0 contained in X7 and R0 contained in X8 are not bonded to each other to form a ring.
In the present invention, in the general formula (1), one R0 of the adjacent two CR0s, in which R0s are bonded to each other to form a ring, preferably represents an aryl group of a 6-membered ring (that is, a phenyl group) or an heteroaryl group of a 6-membered ring, and more preferably a phenyl group.
In the present invention, in the general formula (1), the other R0 other than R0 representing an aryl group or a heteroaryl group, of the adjacent two CR0s, in which R0s are bonded to each other to form a ring, is not particularly limited as long as it is a substituent other than an aryl group or a heteroaryl group. Above all, the substituent is preferably one which is bonded to R0 representing an aryl group or a heteroaryl group to form a ring which is a 5-membered ring, from the viewpoint of maintaining the luminous efficiency of green phosphorescent light.
As the substituent which is bonded to R0 representing an aryl group or a heteroaryl group to form a ring which is a 5-membered ring, a substituent which can form CR1R2, NR3 (R1 to R3 each independently represent a substituent), O, S, or Se as a linking group having one of an atom-linking chain length when forming a fused ring is preferred, a substituent which can form CR1R2, NR3, O, or S is more preferred, a substituent which can form O or S is particularly preferred, and a substituent which can form O is more particularly preferred.
The number of CR0s in X1 to X11 is from 2 to 11, preferably from 5 to 11, more preferably from 8 to 11, particularly preferably from 9 to 11, more particularly preferably 10 or 11, and still more particularly preferably 11.
Furthermore, the number of CR0s in X1 to X11, in which R0 is a substituent, inclusive of R0s in which R0s are bonded to each other to form a ring, is from 2 to 11, more preferably from 3 to 8, and still more preferably 3 or 4.
The position of CR0s in X1 to X11, in which R0 is a substituent, depends on the position of a ring formed by fusion of two CR0s, but it is preferably at least one of X2, X5 and X10, and more preferably at least two of X2, X5 and X10.
The combination of the positions of the adjacent two CR0s in X1 to X11, which are bonded to each other to form a ring, is not particularly limited as long as it is not a combination of X7 and X8, but a combination of X1 and X2, a combination of X2 and X3, a combination of X4 and X5, a combination of X5 and X6, a combination of X6 and X7, a combination of X8 and X9, a combination of X9 and X10, and a combination of X10 and X11 are preferred, and a combination of X1 and X2, a combination of X2 and X3, a combination of X4 and X5, a combination of X5 and X6, a combination of X9 and X10, and a combination of X10 and X11 are more preferred.
In the compound represented by the general formula (1), the number of the rings formed by the mutual bonding of the adjacent two CR0s in X1 to X11 is preferably from 1 to 3, and particularly preferably 1 from the viewpoint of remarkably increasing the luminous efficiency of green phosphorescent light.
In the present invention, the compound represented by the general formula (1) is preferably a compound represented by any one of the following general formulae (2) to (9).
In the general formulae (2) to (9), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent.
XA1 to XA15, XB1 to XB15, XC1 to XC15, XD1 to XD15, XE1 to XE15, XF1 to X15, XG1 to XG15 and XH1 to XH15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent.
In the general formula (2), YA1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YA1 is the same as the preferred range of the linking group having one of an atom-linking chain length, shown when the other R0s other than R0 representing an aryl group or a heteroaryl group, of the adjacent two CR0s, in which R0s are bonded to each other to form a ring, form a fused ring in the general formula (1).
Examples of the substituents represented by substituents R1 and R2 on carbon atoms include the substituent Group A as described above, and the substituent on the carbon atom is preferably an alkyl group, a perfluoroalkyl group, an aryl group, a heteroaryl group, a dialkylamino group, a diarylamino group, an alkoxy group, a cyano group, or a fluorine atom, more preferably an alkyl group or an aryl group, and particularly preferably a methyl group or a phenyl group.
Examples of the substituent represented by R3 on the nitrogen atom include the following Substituent Group B.
<Substituent Group B>>
An alkyl group (preferably having 1 to 30 carbon atoms, more preferably having 1 to 20 carbon atoms, and particularly preferably having 1 to 10 carbon atoms, for example, methyl, ethyl, isopropyl, tert-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, and cyclohexyl), an alkenyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, vinyl, allyl, 2-butenyl, and 3-pentenyl), an alkynyl group (preferably having 2 to 30 carbon atoms, more preferably having 2 to 20 carbon atoms, and particularly preferably having 2 to 10 carbon atoms, for example, propargyl and 3-pentynyl), an aryl group (preferably having 6 to 30 carbon atoms, more preferably having 6 to 20 carbon atoms, and particularly preferably having 6 to 12 carbon atoms, for example, phenyl, p-methylphenyl, naphthyl, and anthranyl), a cyano group, and a heterocyclic group (inclusive of an aromatic heterocyclic group, which preferably has 1 to 30 carbon atoms, and more preferably 1 to 12 carbon atoms and in which examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, a phosphorus atom, a silicon atom, a selenium atom, and a tellurium atom, and specific examples thereof include pyridyl, pyrazinyl, pyrimidyl, pyridazinyl, pyrrolyl, pyrazolyl, triazolyl, imidazolyl, oxazolyl, thiazolyl, isoxazolyl, isothiazolyl, quinolyl, furyl, thienyl, selenophenyl, tellurophenyl, piperidyl, piperidino, morpholino, pyrrolidyl, pyrrolidino, benzoxazolyl, benzoimidazolyl, benzthiazolyl, a carbazolyl group, an azepinyl group, and a silolyl group) These substituents may be further substituted, and examples of the additional substituent include the groups selected from the Substituent Group B as described above.
The substituent represented by R3 on the nitrogen atom is preferably an alkyl group, an aryl group, an aromatic hetero ring group, more preferably an aryl group, and particularly preferably a phenyl group, or a phenyl group substituted with a phenyl group (biphenyl group).
Furthermore, the substituent represented by R3 of YA1 on the nitrogen atom may be connected to XA15 to form a ring.
In the general formula (2), XA1 to XA15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent.
The preferred ranges of XA1 to XA11 are the same as the preferred ranges of X1 to X11 in the general formula (1).
In the general formula (2), examples of the substituent represented by R4 in the case where XA12 to XA15 are CR4s each independently include the Substituent Group A, and the substituent may have an additional substituent. Examples of the additional substituent include the groups selected from the Substituent Group A. Above all, R4s are each independently preferably a hydrogen atom, an aryl group, or a heteroaryl group in the Substituent Group A, and more preferably a hydrogen atom or an aryl group.
The aryl group represented by R4 preferably has 6 to 30 carbon atoms, more preferably has 6 to 20 carbon atoms, and particularly preferably has 6 to 18 carbon atoms, and examples thereof include a phenyl group, a xylyl group, a biphenyl group, a terphenyl group, a naphthyl group, an anthranyl group, and a triphenylenyl group.
The heteroaryl group represented by R4 preferably has 5 to 30 ring members, more preferably has 5 to 20 ring members, and particularly preferably has 5 to 15 ring members, and examples thereof include a pyridyl group, a pyrimidyl group, a triazyl group, a pyrazyl group, a pyridazyl group, a carbazolyl group, a dibenzothiophenyl group, and a dibenzofuranyl group.
R4 contained in XA12 to XA15 may have an additional substituent represented by the Substituent Group A as described above. In the case where R4 has such an additional substituent, the substituent is preferably substituent containing an aryl group, or at least one of a pyridine ring, a pyrimidine ring, a triazine ring, a cyano group, and a carbonyl group. Above all, an aryl group-substituted aryl group is more preferred, and the additional substituent which may be contained in R4 is particularly preferably further substituted. R4 is preferably a phenyl group-substituted phenyl group (biphenyl group), or a cyano-substituted, phenyl group-substituted, or aryl group-substituted phenyl group.
The number of CR4s in XA12 to XA15 is preferably from 1 to 4, more preferably from 2 to 4, particularly preferably 3 or 4, and more particularly preferably 4.
Furthermore, the number of CR4s in XA12 to XA15, in which R4 is a substituent, is preferably 0 or 1, and more preferably 0.
The position of CR4s in XA12 to XA15, in which R4 is a substituent, is preferably at least one of the positions adjacent to YA1 (the position of XA15 in the general formula (2)), and more preferably only one of the positions adjacent to YA1.
The general formula (2) is more preferably represented by the general formula (10) as described later.
In the general formula (3), YB1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YB1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YB1 on the nitrogen atom may be connected to XB1 or XB12 to form a ring.
In the general formula (3), XB1 to XB15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XB1 to XB15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YB1 and XB1 to XB15 in the general formula (3) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XB12 to XB15 have CR4 as a substituent is preferably a position adjacent to YB1 (the position of XB12 in the general formula (3)).
The general formula (3) is more preferably represented by the general formula (11) as described later.
In the general formula (4), YC1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YC1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YC1 on the nitrogen atom may be connected to XC6 or XC15 to form a ring.
In the general formula (4), XC1 to XC15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XC1 to XC15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YC1 and XC15 to XC15 in the general formula (4) is the same as the preferred relationship between YA1 and XA15 to XA15 in the general formula (2), that is, the position of CR4 in the case where XC12 to XC15 have CR4 as a substituent is preferably a position adjacent to YC1 (the position of XC15 in the general formula (4)).
The general formula (4) is more preferably represented by the general formula (12) as described later.
In the general formula (5), YD1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YD1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent on the nitrogen atom represented by R3 of YD1 may be connected to XD12 to form a ring.
In the general formula (5), XD1 to XD15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XD1 to XD15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YD1 and XD1 to XD15 in the general formula (5) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XD12 to XD15 have CR4 as a substituent is preferably a position adjacent to YD1 (the position of XD12 in the general formula (5)).
The general formula (5) is more preferably represented by the general formula (13) as described later.
In the general formula (6), YE1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YE1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YE1 on the nitrogen atom may be connected to XE7 or XE15 to form a ring.
In the general formula (6), XE1 to XE15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XE1 to XE15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YE1 and XE1 to XE15 in the general formula (6) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XE12 to XE15 have CR4 as a substituent is preferably a position adjacent to YE1 (the position of XE15 in the general formula (6)).
The general formula (6) is more preferably represented by the general formula (14) as described later.
In the general formula (7), YF1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YF1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YF1 on the nitrogen atom may be connected to XF4 or XF12 to form a ring.
In the general formula (7), XF1 to XF15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XF1 to XF15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YF1 and XF1 to XF15 in the general formula (7) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XF12 to XF15 have CR4 as a substituent is preferably a position adjacent to YF1 (the position of XF12 in the general formula (7)).
The general formula (7) is more preferably represented by the general formula (15) as described later.
In the general formula (8), YG1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YG1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YG1 on the nitrogen atom may be connected to XG15 to form a ring.
In the general formula (8), XG1 to XG15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XG1 to XG15 are the same as the preferred ranges of XA1 to X15 in the general formula (2).
The preferred relationship between YG1 and XG1 to XG15 in the general formula (8) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XG12 to XG15 have CR4 as a substituent is preferably a position adjacent to YG1 (the position of XG15 in the general formula (8)).
The general formula (8) is more preferably represented by the general formula (16) as described later.
In the general formula (9), YH1 represents CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. The preferred range of YH1 is the same as the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YH1 on the nitrogen atom may be connected to XH5 or XH12 to form a ring.
In the general formula (9), XH1 to XH15 each independently represent CR4 or N, and CR4s each independently represent a hydrogen atom or a substituent. The preferred ranges of XH1 to XH15 are the same as the preferred ranges of XA1 to XA15 in the general formula (2).
The preferred relationship between YH1 and XH15 to XH15 in the general formula (9) is the same as the preferred relationship between YA1 and XA1 to XA15 in the general formula (2), that is, the position of CR4 in the case where XH12 to XH15 have CR4 as a substituent is preferably a position adjacent to YH1 (the position of XH12 in the general formula (9)).
The general formula (9) is more preferably represented by the general formula (17) as described later.
In the present invention, the compound represented by the general formula (1) is preferably a compound represented by any one of the general formulae (2), (4) to (7), and (8) cut of the general formulae (2) to (9) from the viewpoints that the planarity and the stability of molecules are good, and the T1 can be easily increased that a light emitting material as described later, and more preferably a compound represented by any one of the general formulae (2), (4) to (6), and (8) from the viewpoints that the T1 can be easily increased that a light emitting material as described later.
In the present invention, the compound represented by the general formula (1) is preferably a compound represented by any one of the following general formulae (10) to (17).
In the general formulae (10) to (17), YA1 to YH1 each independently represent CR1R2, NR3, O, S, or Se, and R1 to R3 each independently represent a substituent. RA1 to RA15, RB1 to RB15, RC1 to RC15, RD1 to RD15, RE1 to RE15, RF1 to RF15, RG1 to RG15 and RH1 to RH15 each independently represent a hydrogen atom or a substituent.
In the general formula (10), the definition and the preferred range of YA1 are the same as the definition and the preferred range of YA1 in the general formula (2).
Furthermore, the substituent represented by R3 of YA1 on the nitrogen atom may be connected to RA15 to form a ring.
In the general formula (10), RA1 to RA15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RA1 to RA15 are the same as the preferred ranges of R4 contained in each of XA1 to XA15 in the case where XA1 to XA15 in the general formula (2) represent all CR4.
The preferred relationship between YA1 and RA1 to RA15 in the general formula (10) is the same as the preferred relationship between YA1 in the general formula (2) and R4 contained in each of XA1 to XA15 in the case where XA1 to XA15 in the general formula (2) represent all CR4, that is, the position of the substituent in the case where RA12 to RA15 have a substituent is preferably a position adjacent to YA1 (the position of RA15 in the general formula (10)).
In the general formula (11), the definition and the preferred range of YB1 are the same as the definition and the preferred range of YB1 in the general formula (3).
Furthermore, the substituent represented by R3 of YB1 on the nitrogen atom may be connected to RB1 or RB2 to form a zing. In the general formula (11), RB1 to RB15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RB1 to RB15 are the same as the preferred ranges of R4 contained in each of XB1 to XB15 in the case where XB1 to XB15 in the general formula (3) represent all CR4.
The preferred relationship between YB1 and RB1 to RB15 in the general formula (11) is the same as the preferred relationship between YB1 in the general formula (3) and R4 contained in each of XB1 to XB15 in the case where XB1 to XB15 in the general formula (3) represent all CR4, that is, the position of the substituent in the case where RB12 to RB15 have a substituent is preferably a position adjacent to YB1 (the position of RB12 in the general formula (11)).
In the general formula (12), the definition and the preferred range of YC1 are the same as the definition and the preferred range of YC1 in the general formula (4).
Furthermore, the substituent represented by R3 of YC1 on the nitrogen atom may be connected to RC6 or RC15 to form a ring.
In the general formula (12), RC1 to RC15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RC1 to RC15 are the same as the preferred ranges of R4 contained in each of XC1 to XC15 in the case where XC1 to XC15 in the general formula (4) represent all CR4.
The preferred relationship between YC1 and RC1 to RC15 in the general formula (12) is the same as the preferred relationship between YC1 in the general formula (4) and R4 contained in each of XC1 to XC15 in the case where XC1 to XC15 in the general formula (4) represent all CR4, that is, the position of the substituent in the case where RC12 to RC15 have a substituent is preferably a position adjacent to YC1 (the position of RC15 in the general formula (12)).
In the general formula (13), the definition and the preferred range of YD1 are the same as the definition and the preferred range of YD1 in the general formula (5).
Furthermore, the substituent represented by R3 of YD1 on the nitrogen atom may be connected to RD12 to form a ring.
In the general formula (13), RD1 to RD15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RD1 to RD15 are the same as the preferred ranges of R4 contained in each of XD1 to XD15 in the case where XD1 to XD12 in the general formula (5) represent all CR4.
The preferred relationship between YD1 and RD1 to RD15 in the general formula (13) is the same as the preferred relationship between YD1 in the general formula (5) and R4 contained in each of XD1 to XD15 in the case where XD1 to XD15 in the general formula (5) represent all CR4, that is, the position of the substituent in the case where RD12 to RD15 have a substituent is preferably a position adjacent to YD1 (the position of RD12 in the general formula (13)).
In the general formula (14), the definition and the preferred range of YE1 are the same as the definition and the preferred range of YE1 in the general formula (6).
Furthermore, the substituent, represented by R3 of YE1 on the nitrogen atom may be connected to RE7 or RE15 to form a ring. In the general formula (14), RE1 to RE15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RE1 to RE15 are the same as the preferred ranges of R4 contained in each of XE1 to XE15 in the case where XE1 to XE15 in the general formula (6) represent all CR4.
The preferred relationship between YE1 and RE1 to RE15 in the general formula (14) is the same as the preferred relationship between YE1 in the general formula (6) and R4 contained in each of XE1 to XE15 in the case where XE1 to XE15 in the general formula (6) represent all CR4, that is, the position of the substituent in the case where RE2 to RE1 have a substituent is preferably a position adjacent to Y1 (the position of RE15 in the general formula (14)).
In the general formula (15), the definition and the preferred range of YF1 are the same as the definition and the preferred range of YF1 in the general formula (7).
Furthermore, the substituent represented by R3 of YF1 on the nitrogen atom may be connected to RF4 or RE12 to form a ring.
In the general formula (15), RF1 to R15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RF1 to RF15 are the same as the preferred ranges of R4 contained in each of XF1 to XF15 in the case where XF1 to XF15 in the general formula (7) represent all CR4.
The preferred relationship between YF1 and RF1 to RF15 in the general formula (15) is the same as the preferred relationship between YF1 in the general formula (7) and R4 contained in each of XF1 to X15 in the case where XF1 to XF15 in the general formula (7) represent all CR4, that is, the position of the substituent in the case where RF12 to RF15 have a substituent is preferably a position adjacent to YF1 (the position of RF12 in the general formula (15)).
In the general formula (16), the definition and the preferred range of YG1 are the same as the definition and the preferred range of YG1 in the general formula (8).
Furthermore, the substituent represented by R3 of YG1 on the nitrogen atom may be connected to XG15 to form a ring.
In the general formula (16), RG1 to RG15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RG1 to RG15 are the same as the preferred ranges of R4 contained in each of XG1 to XG15 in the case where XG1 to X11 in the general formula (8) represent all CR4.
The preferred relationship between YG1 and RG1 to RG15 in the general formula (16) is the same as the preferred relationship between YG1 in the general formula (8) and R4 contained in each of XG1 to XG15 in the case where XG1 to XG15 in the general formula (8) represent all CR4, that is, the position of the substituent in the case where RG12 to RG15 have a substituent is preferably a position adjacent to YG1 (the position of RG15 in the general formula (16)).
In the general formula (17), the definition and the preferred range of YH1 are the same as the definition and the preferred range of YH1 in the general formula (9).
Furthermore, the substituent represented by R3 of YH1 on the nitrogen atom may be connected to RH5 or RH12 to form a ring.
In the general formula (17), RH1 to RH15 each independently represent a hydrogen atom or a substituent, and the preferred ranges of RH1 to RH15 are the same as the preferred ranges of R4 contained in each of XH1 to XH15 in the case where XH1 to X15 in the general formula (9) represent all CR4.
The preferred relationship between YH1 and RH1 to RH15 in the general formula (17) is the same as the preferred relationship between YH1 in the general formula (9) and R4 contained in each of XH1 to XH15 in the case where XH1 to XH15 in the general formula (9) represent all CR4, that is, the position of the substituent in the case where RH12 to RH15 have a substituent is preferably a position adjacent to YH1 (the position of RH12 in the general formula (17)).
In the present invention, the compound represented by the general formula (1) is preferably a compound represented by any one of the general formulae (10), (12) to (15), and (16) out of the general formulae (10) to (17) from the viewpoints that the planarity and the stability of molecules are good, and the T1 can be easily increased that a light emitting material as described later, and more preferably a compound represented by any one of the general formulae (10), (12) to (14), and (16) from the viewpoints that the T1 can be easily increased that a light emitting material as described later.
The molecular weight of the compound represented by the general formula (1) is usually from 400 to 1500, preferably from 450 to 1200, more preferably from 500 to 1100, and still more preferably from 550 to 1000. The molecular weight of 450 or more is advantageous in forming an amorphous thin film of good quality, and the molecular weight of 1200 or less is advantageous in improving solubility and sublimation properties, and thus improving the purity of the compound. In the organic electroluminescent element of the present invention, the molecular weight of the compound represented by the general formula (1) is preferably 550 or more from the viewpoint of a glass transition temperature. On the other hand, from the viewpoint of lamination of a composition including the compound represented by the general formula (1) by deposition, the molecular weight of the compound represented by the general formula (1) is preferably 1200 or less.
In the case where the hydrocarbon compound represented by the general formula (1) is used in a host material of a light emitting layer or in a charge transporting material of a layer adjacent to the light emitting layer, in an organic electroluminescent element, when the energy gap in the thin film state (the minimum excited triplet (T1) energy in the thin film state in the case of the light emitting material being a phosphorescence emitting material) is larger than in the light emission material as described later, the quench of the light emission is prevented, which is advantageous in enhancing the efficiency. On the other hand, from the viewpoint of chemical stability of the compound, it is preferable that an energy gap and T1 energy be not too large.
In the present invention, the value of LUMO of the compound represented by the general formula (1), as determined by an electron density functional theory (B3LYP/6-31G (d) level), is preferably more than 1.25, more preferably 1.4 or more, and particularly preferably from 1.4 to 1.9.
The minimum excited triplet (T1) energy in the film state of the compound represented by the general formula (1) is preferably from 1.77 eV (40 kcal/mol) to 3.51 eV (81 kcal/mol), and more preferably from 2.39 eV (55 kcal/mol) to 3.25 eV (75 kcal/mol). In the organic electroluminescent element of the present invention, it is preferable that T1 energy of the compound represented by the general formula (1) be more than T1 energy of the above-mentioned phosphorescent light emitting material, from the viewpoint of luminous efficiency. In particular when the luminescent color from the organic electroluminescent element is green (the light emission peak wavelength is from 490 nm to 580 nm), from the viewpoint of luminous efficiency, T1 energy is more preferably from 2.39 eV (55 kcal/mol) to 2.82 eV (65 kcal/mol).
By measuring the phosphorescent light emitting spectrum of a thin film of the material, the T1 energy can be found from the short-wavelength end thereof. For instance, a film of the material is formed in a thickness of about 50 nm by a vacuum deposition method over a washed quartz glass substrate, and the phosphorescence spectrum of the thin film is measured using an F-7000 Hitachi spectrofluoro-photometer (Hitachi High-Technologies Corporation) at the temperature of liquid nitrogen. The T1 energy can be found by converting the rising wavelength on the short-wavelength side of the light emission spectrum thus obtained to energy units.
From the viewpoint of stable operation of the organic electroluminescent element with respect to heat emission during high-temperature driving or element driving, the glass transition temperature of the compound represented by the general formula (1) in the organic electroluminescent element of the present invention is preferably a compound having a glass transition temperature of 100° C. or higher. The glass transition temperature (Tg) of the compound represented by the general formula (1) is more preferably from 100° C. to 400° C., particularly preferably from 120° C. to 400° C., and still more preferably from 140° C. to 400° C.
If the purity of the compound represented by the general formula (1) is low, impurities serve as a trap for charge transport or accelerate degradation of the element, and therefore, higher purity of the compound represented by the general formula (1) is preferred. The purity can be measured, for example, by high performance liquid chromatography (HPLC), and the surface area ratio of the compound represented by the general formula (1) as detected at an optical absorption intensity of 254 nm is preferably 95.0% or more, and more preferably 97.0% or more, particularly preferably 99.0% or more, and most preferably 99.9% or more. Examples of a method for increasing the purity of the compound represented by the general formula (1) include recrystallization and sublimation.
Specific examples of the compound represented by the general formula (1) are list, but the present invention is not limited thereto.
In the compounds represented by the following general formula (10), RA1, RA4, RA6 to RA9, RA11 to RA14 represent a hydrogen atom, and the other groups are groups described in Tables below.
In the compounds represented by the following general formula (11), RB1, RB4, RB6 to RB9, RB11, RB13 to RB15 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the compounds represented by the following general formula (12), RC1, RC3, RC6 to RC9, RC11 to RC14 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the compound represented by the following general formula (13), RD1, RD3, RD6 to RD9, RD11, RD13 to RD15 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the compound represented by the following general formula (14), RE1, RE3, RE4, RE7 to RE9, RE11, RE13 to RE15 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the compound represented by the following general formula (15), RF1, RF3, RF4, RF7 to RF9, RF11, RF13 to RF15 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the following general formula (16), RG1, RG3, RG4, RG5, RG8, RG9, RG11, and RG12 to RG14 each represent a hydrogen atom, and the other groups are the groups described in Tables below.
In the compound represented by the following general formula (17), RH1, RH3, RH4, RH5, RH8, RH9, RH11, RH13 to RH15 each represent a hydrogen atom, and the other groups are groups described in Tables below.
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The compounds exemplified as the compound represented by the general formula (1) can be synthesized by the methods described in, for example, WO2010/042107, WO2010/131855, JP-A-2010-087496, and the like.
The compounds represented by the general formulae (2) to (9) can be each preferably synthesized by the following scheme. However, the following synthesis scheme is one of synthesis and the synthesis can be also conducted by other known methods.
Synthesis Route of General Formula (2)
Synthesis Route of General Formula (3)
Synthesis Route of General Formula (4)
Synthesis Route of General Formula (5)
Synthesis Route of General Formula (6)
Synthesis Route of General Formula (7)
Synthesis Route of General Formula (8)
Synthesis Route of General Formula (9)
In the present invention, the compound represented by the general formula (1) is not limited in its use and can be contained in any one of the organic layers. With regard to the layer into which the compound represented by the general formula (1) is introduced, the compound is preferably contained in any one of the light emitting layer, a layer between the light emitting layer and the cathode (in particular, a layer adjacent to the light emitting layer), and a layer between the light emitting layer and the anode, more preferably contained in any one of the light emitting layer, an electron transporting layer, an electron injecting layer, an exciton blocking layer, a hole blocking layer, and an electron blocking layer, or in a plurality of layers thereof, still more preferably contained in any one of the light emitting layer, an electron transporting layer, a hole blocking layer, and a hole transporting layer, and particularly preferably contained in the light emitting layer or an electron transporting layer. Further, the compound represented by the general formula (1) may be used in a plurality of the layers. For example, the compound may be used in both of the light emitting layer and an electron transporting layer.
In the case where the compound represented by the general formula (1) is contained in the light emitting layer, the compound represented by the general formula (1) is contained in the amount of, preferably 0.1% by mass to 99% by mass, more preferably 1% by mass to 97% by mass, and still more preferably 10% by mass to 96% by mass, with respect to the total mass of the light emitting layer. In the case where the compound represented by the general formula (1) is further contained in the layers other than the light emitting layer, it is contained in the amount of, preferably 50% by mass to 100% by mass, and more preferably 85% by mass to 100% by mass, with respect to the total mass of the layers other than the light emitting layer.
(Phosphorescent Light Emitting Material)
In the present invention, the light emitting layer preferably contains at least one phosphorescent light emitting material. In the present invention, in addition to the phosphorescent light emitting material, a fluorescent light emitting material or a phosphorescent light emitting material other than the phosphorescent light emitting material contained in the light emitting layer can be used as the light emitting material.
The fluorescent light emitting material and the phosphorescent light emitting material are described in detail in, for example, paragraph Nos. [0100] to [0164] of JP-A-2008-270736 and paragraph Nos. [0088] to [0090] of JP-A-2007-266458, and the detailed descriptions in these publications can be applied to the present invention.
Examples of the phosphorescent light emitting material which can be used in the present invention include phosphorescent light emitting compounds described in patent documents, for example, U.S. Pat. Nos. 6,303,238B1, 6,097,147, WO00/57676, WO00/70655, WO01/08230, WO01/39234A2, WO01/41512A1, WO02/02714A2, WO02/15645A1, WO02/44189A1, WO05/19373A2, JP-A-2001-247859, JP-A-2002-302671, JP-A-2002-117978, JP-A-2003-133074, JP-A-2002-235076, JP-A-2003-123982, JP-A-2002-170684, EP1211257, JP-A-2002-226495, JP-A-2002-234894, JP-A-2001-247859, JP-A-2001-298470, JP-A-2002-173674, JP-A-2002-203678, JP-A-2002-203679, JP-A-2004-357791, JP A-2006-256999, JP-A-2007-19462, JP-A-2007-84635, and JP-A-2007-96259. Above all, examples of the light emitting material which is more preferred include phosphorescent light emitting metal complex compounds such as Ir complexes, Pt complexes, Cu complexes, Re complexes, W complexes, Rh complexes, Ru complexes, Pd complexes, Os complexes, Eu complexes, Tb complexes, Gd complexes, Dy complexes, and Ce complexes, with Ir complexes, Pt complexes, and Re complexes being particularly preferred. Above all, Ir complexes, Pt complexes, and Re complexes each including at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond are preferred. Furthermore, from the viewpoints of luminous efficiency, driving durability, and chromaticity, Ir complexes and Pt complexes are particularly preferred, and Ir complexes are the most preferred.
These phosphorescent light emitting metal complex compounds are preferably contained together with the compound represented by the general formula (1) in the light emitting layer.
As the phosphorescent light emitting material contained in the light emitting layer, an iridium complex represented by the general formula (E-1) shown below is preferably used. The iridium complex represented by the general formula (E-1) will be described below.
In the general formula (E-1), Z1 and Z2 each independently represent a carbon atom or a nitrogen atom.
A1 represents an atomic group that together with Z1 and a nitrogen atom forms a 5- or 6-membered hetero ring.
B1 represents an atomic group that together with Z2 and a carbon atom forms a 5- or 6-membered ring.
(X—Y) represents a mono-anionic bidentate ligand.
nE1 represents an integer of 1 to 3.
nE1 represents an integer of 1 to 3, and preferably 2 or 3.
Z1 and Z2 each independently represent a carbon atom or a nitrogen atom. Z1 and Z2 are each preferably a carbon atom.
A1 represents an atomic group that together with Z1 and a nitrogen atom forms a 5- or 6-membered hetero ring. Examples of the 5- of 6-membered hetero ring formed of A1, Z1, and a nitrogen atom include a pyridine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, an oxadiazole ring, and a thiadiazole ring.
From the viewpoints of stability of complexes, control of light emitting wavelength, and luminescent quantum yield, examples of the 5- of 6-membered hetero ring formed of A1, Z1, and a nitrogen atom preferably include a pyridine ring, a pyrazine ring, an imidazole ring, and a pyrazole ring, more preferably include a pyridine ring, an imidazole ring, and a pyrazine ring, still more preferably include a pyridine ring and an imidazole ring, and most preferably include a pyridine ring.
The 5- of 6-membered hetero ring formed of A1, Z1, and a nitrogen atom may have a substituent, and as the substituent, the Substituent Group A can be applied. The substituent is appropriately selected to control the light emitting wavelength and the potentials, but in the case of shortening the wavelength, an electron donating group, a fluorine atom, and an aromatic ring group are preferred, and for example, an alkyl group, a dialkylamino group, an alkoxy group, a fluorine atom, an aryl group, a heteroaryl group, and the like are selected. Further, in the case of increasing the wavelength, an electron withdrawing group is preferred, and for example, a cyano group, a perfluoroalkyi group, and the like are preferably selected. For the purpose of adjusting the molecular interaction, an alkyl group, a cycloalkyl group, an aryl group, and the like are preferably selected.
The substituent on carbon is preferably an alkyl group, a perfluoroalkyl group, an aryl group, a heteroaryl group, a dialkylamino group, a diarylamino group, an alkoxy group, a cyano group, or a fluorine atom.
The substituent on nitrogen is preferably an alkyl group, an aryl group, or a heteroaryl group, and from the viewpoint of the stability of complexes, the substituent is preferably an alkyl group or an aryl group.
The substituents may be connected to each other to form a fused ring, and examples of the ring thus formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, a thiophene ring, and a furan ring. The ring thus formed may have a substituent, and examples of the substituent include the substituents on carbon atoms and the substituents on nitrogen atoms, as described above.
B1 represents a 5- or 6-membered ring containing Z2 and carbon atoms. Examples of the 5- or 6-membered ring formed of B1, Z2 and a carbon atom include a benzene ring, a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, an oxadiazol e ring, a thiadiazole ring, a thiophene ring, and a furan ring.
From the viewpoints of the stability of complexes, the control of light emitting wavelength, and the luminescent quantum yield, the 5- or 6-membered ring formed of B1, Z2 and a carbon atom is preferably a benzene ring, a pyridine ring, a pyrazine ring, an imidazole ring, a pyrazole ring, or a thiophene ring, more preferably a benzene ring, a pyridine ring, or a pyrazole ring, and still more preferably a benzene ring or a pyridine ring.
The 5- or 6-membered ring formed of B1, Z2 and a carbon atom may have a substituent, as the substituent on a carbon atom, the Substituent Group A can be applied, and as the substituent on a nitrogen atom, the Substituent Group B can be applied.
The substituent on carbon is preferably an alkyl group, a perfluoroalkyl group, an aryl group, a heteroaryl group, a dialkylamino group, a diarylamino group, an alkoxy group, a cyano group, or a fluorine atom.
The substituent on carbon is appropriately selected to control the light emitting wavelength and the potentials, but in the case of increasing the wavelength, an electron donating group and an aromatic ring group are preferred, and for example, an alkyl group, a dialkylamino group, an alkoxy group, an aryl group, a heteroaryl group, and the like are selected. Further, in the case of shortening the wavelength, an electron withdrawing group is preferred, and for example, a fluorine atom, cyano group, a perfluoroalkyl group, and the like are selected. For the purpose of adjusting the molecular interaction, an alkyl group, a cycloalkyl group, an aryl group, and the like are preferably selected.
The substituent on nitrogen is preferably an alkyl group, an aryl group, or an aromatic hetero ring group, and from the viewpoint of the stability of complexes, the substituent is preferably an alkyl group or an aryl group. The substituents may be connected to each other to form a fused ring, and examples of the ring thus formed include a benzene ring, a pyridine ring, a pyrazine ring, a pyridazine ring, a pyrimidine ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazole ring, a thiophene ring, and a furan ring. The ring thus formed may have a substituent, and examples of the substituent include the substituents on carbon atoms and the substituents on nitrogen atoms, as described above.
In addition, the substituents of the 5- or 6-membered ring formed of A1, Z1, and a nitrogen atom and the 5- or 6-membered ring formed of B1, Z2, and a carbon atom may be connected to each other to form a fused ring as described above.
(X—Y) represents a mono-anionic bidentate ligand. Examples of the mono-anionic bidentate ligand described in pp. 89 to 90 of WO02/15645, Lamansky et al.
The mono-anionic bidentate ligand represented by (X—Y) is preferably a mono-anionic bidentate ligand represented by the following general formula (L-1).
In the general formula (L-1), RL1 and RL2 each independently represent an alkyl group, an aryl group, or a heteroaryl group.
RL3 represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group.
The alkyl group represented by RL1 to RL2 may have a substituent, and may be saturated or unsaturated. In the case where the alkyl group have a substituent, examples of the substituent include the following substituent Z′, preferred examples of the substituent Z′ include a phenyl group, a heteroaryl group, a fluorine atom, a silyl group, an amino group, a cyano group, or a group formed by a combination thereof, and more preferably a phenyl group, a fluorine atom, or a cyano group. The alkyl group represented by RL1 to RL3 is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 1 to 5 carbon atoms.
<<Substituent Z′>
The substituents Z′ represents an alkyl group (preferably having 1 to 10 carbon atoms, more preferably having 1 to 6 carbon atoms, and still more preferably having 1 to 4 carbon atoms, for example, methyl, ethyl, isopropyl, n-propyl, tert-butyl, isobutyl, n-butyl, neopentyl, n-pentyl, n-hexyl, cyclopropyl, cyclopentyl, and cyclohexyl), an alkenyl group (preferably having 2 to 8 carbon atoms, and more preferably having 2 to 5 carbon atoms, for example, vinyl), an aryl group (preferably having 6 to 30 carbon atoms, and more preferably having 6 to 20 carbon atoms, for example, a phenyl group, a naphthyl group, an anthacenyl group, a tetracenyl group, a pyrenyl group, a perylenyl group, a triphenylenyl group, and a chrysenyl group), a heteroaryl group (preferably having 4 to 30 carbon atoms, and more preferably having 4 to 20 carbon atoms, for example, pyridine, pyrazine, pyrimidine, pyridazine, triazine, thiophene, furan, oxazole, thiazole, imidazole, pyrazole, triazole, oxadiazole, and thiadiazole), an alkoxy group (preferably having 1 to 8 carbon atoms, and more preferably having 1 to 5 carbon atoms, for example, a methoxy group, an ethoxy group, an n-propyloxy group, and an iso-propyloxy group), a phenoxy group, a halogen atom (preferably a fluorine atom), a silyl group (preferably having 4 to 30 carbon atoms, and more preferably having 4 to 20 carbon atoms, for example, a trimethylsilyl group, a triethylsilyl group, and a triphenylsilyl group), an amino group (preferably having 2 to 60 carbon atoms, and more preferably having 2 to 40 carbon atoms, for example, a dimethylamino group, a diethylamino group, and a diphenylamino group), a cyano group, or a group formed by a combination thereof. A plurality of substituents Z′ may be connected to each other to form an aryl ring. Examples of the aryl ring formed by a mutual combination of a plurality of substituents Z′s include a phenyl ring and a pyridine ring, with a phenyl group being preferred.
The aryl groups represented by RL1 to RL3 may be subjected to ring fusion and may have a substituent. In the case of having a substituent, examples of the substituent include the above-described substituents Z′, and the substituent Z′ is preferably an alkyl group or an aryl group, and more preferably an alkyl group. The aryl group represented by RL1 to RL3 is preferably an aryl group having 6 to 30 carbon atoms, and more preferably an aryl group having 6 to 18 carbon atoms.
The heteroaryl groups represented by RL1 to RL3 may be subjected to ring fusion and may have a substituent. In the case of having a substituent, examples of the substituent include the above-described substituents Z′, and the substituent Z′ is preferably an alkyl group or an aryl group, and more preferably an alkyl group. The heteroaryl group represented by RL1 to RL3 is preferably a heteroaryl group having 4 to 12 carbon atoms, and more preferably a heteroaryl group having 4 to 10 carbon atoms.
RL1 and RL2 are preferably an alkyl group or an aryl group, more preferably an alkyl group or a phenyl group, and particularly preferably an alkyl group.
The alkyl group represented by RL1 and RL2 is preferably an alkyl group having a total carbon number of 1 to 8, and more preferably an alkyl group having a total carbon number of 1 to 5, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an iso-butyl group, a t-butyl group, an n-butyl group, and a cyclohexyl group, preferably a methyl group, an ethyl group, an iso-butyl group, and a t-butyl group, and particularly preferably a methyl group.
RL3 is preferably a hydrogen atom, an alkyl group, or aryl group, more preferably a hydrogen atom or alkyl group, and particularly preferably a hydrogen atom.
A preferred embodiment of the iridium complex represented by the general formula (E-1) is an iridium complex material represented by the following general formula (E-2).
Next, the general formula (E-2) will be described.
In the general formula (E-2), AE1 to AE8 each independently represent a nitrogen atom or C—RE.
RE represents a hydrogen atom or a substituent.
(X—Y) represents a mono-anionic bidentate ligand.
nE2 represents an integer of 1 to 3.
AE1 to AE8 each independently represent a nitrogen atom or C—RE. RE represents a hydrogen atom or a substituent, and REs may be connected to each other to forma ring. Examples of the ring thus formed include the same rings as the fused rings exemplified in the general formula (E-1) as described above. Examples of the substituent represented by RE include those exemplified as the Substituent Group A.
AE1 to AE4 are preferably C—RE, and in the case where AE1 to AE4 are C—RE, RE of AE3 is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom, or a cyano group, more preferably a hydrogen atom, an alkyl group, an amino group, an alkoxy group, an aryloxy group, or a fluorine atom, particularly preferably a hydrogen atom or fluorine atom, and RE of AE1, AE2 and AE4 is preferably a hydrogen atom, an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, a fluorine atom, or a cyano group, more preferably a hydrogen atom, an alkyl group, an amino group, an alkoxy group, an aryloxy group, or a fluorine atom, and particularly preferably a hydrogen atom.
AE5 to AE8 are preferably C—RE, in the case where AE5 to AE8 are C—RE, RE is preferably a hydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, an aromatic hetero ring group, a dialkylamino group, a diarylamino group, an alkyloxy group, a cyano group, or a fluorine atom, more preferably a hydrogen atom, an alkyl group, a perfluoroalkyl group, an aryl group, a dialkylamino group, a cyano group, or a fluorine atom, and still more preferably a hydrogen atom, an alkyl group, a trifluoromethyl group, or a fluorine atom. Further, if possible, the substituents may be connected to each other to form a fused ring structure. In the case where the light emitting wavelength is shifted to a short wavelength side, A6 is preferably a nitrogen atom.
(X—Y) and nE2 have the same meanings as (X—Y) and nE1 in the general formula (E-1), and the preferred ranges thereof are also the same.
A more preferred embodiment of the compound represented by the general formula (E-2) is a compound represented by the following general formula (E-3).
In the general formula (E-3), RT1, RT2, RT3, RT4, RT5, RT6 and RT7 each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, —CN, a perfluoroalkyl group, a trifluorovinyl group, —CO2R, —C(O)R, —NR2, —NO2, —OR, a halogen atom, an aryl group, or a heteroaryl group, and further, it may have a substituent Z. Rs each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
A represents CR′ or a nitrogen atom, R′ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, —CN, a perfluoroalkyl group, a trifluorovinyl group, —CO2R, —C(O)R, —NR2, —NO2, —OR, a halogen atom, an aryl group, or a heteroaryl group, and further, it may have a substituent Z. Rs each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
Any two of RT1 to RT7, and R′ may be bonded to each other to form fused 4- to 7-membered rings, the fused 4- to 7-membered rings are cycloalkyl, aryl, or heteroaryl, and the fused 4- to 7-membered rings may further have substituents Z. Above all, it is preferable that RT1 and RT7, or RT5 and TT6 be subjected to ring fusion to form a benzene ring, and it is particularly preferable that RT5 and RT6 be subjected to ring fusion to form a benzene ring.
Zs each independently represent a halogen atom, —R″, —OR″, —N(R″)2, —SR″, —C(O)R″, —C(O)OR″, —C(O)N(R″)2, —CN, —NO2, —SO2, —SOR″, —SO2R″, or —SO3R″, and R″s each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
(X—Y) represents a mono-anionic bidentate ligand, and nE3 represents an integer of 1 to 3.
The alkyl group may have a substituent, and may be saturated or unsaturated, and examples of the group that may be the substituent include the above-described substituents Zs. The alkyl group represented by RT1 to RT7, and R′ is preferably an alkyl group having a total carbon number of 1 to 8, and more preferably an alkyl group having a total carbon number of 1 to 6, and examples thereof include a methyl group, an ethyl group, an i-propyl group, a cyclohexyl group, and a t-butyl group.
The cycloalkyl group may have a substituent, and may be saturated or unsaturated, and examples of the group that may be the substitute include the above-described substituent Z. The cycloalkyl group represented by RT1 to RT7, and R′ is preferably a cycloalkyl group having 4 to 7 ring members, more preferably a cycloalkyl group having a total carbon number of 5 to 6, and examples thereof include a cyclopenthyl group and a cyclohexyl group.
The alkenyl group represented by RT1 to RT7, and R′ preferably has 2 to 30 carbon atoms, more preferably has 2 to 20 carbon atoms, and particularly preferably has 2 to 10 carbon atoms, and examples thereof include vinyl, allyl, 1-propenyl, 1-isopropenyl, 1-butenyl, 2-butenyl, and 3-pentenyl.
The alkynyl group represented by RT1 to RT7, and R′ preferably has 2 to 30 carbon atoms, more preferably has 2 to 20 carbon atoms, and particularly preferably has 2 to 10 carbon atoms, and examples thereof include ethynyl, propargyl, 1-propynyl, and 3-pentynyl.
The perfluoroalkyl group represented by RT1 to RT7, and R′ includes a group obtained by substituting all the hydrogen atoms in the above-mentioned alkyl group with fluorine atoms.
The aryl group represented by RT1 to RT7, and R′ is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and examples thereof include a phenyl group, a tolyl group, and a naphthyl group.
The heteroaryl group represented by RT1 to RT7, and R′ is preferably a heteroaryl group having 5 to 8 carbon atoms, and more preferably a substituted or unsubstituted 5- or 6-membered heteroaryl group, and examples thereof include a pyridyl group, a pyrazinyl group, a pyridazinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, a cinnolinyl group, a phthalazinyl group, a quinoxalinyl group, a pyrrolyl group, an indolyl group, a furyl group, a benzofuryl group, a thienyl group, a benzothienyl group, a pyrazolyl group, an imidazolyl group, a benzimidazolyl group, a triazolyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, an isothiazolyl group, a benzisothiazolyl group, a thiadiazolyl group, an isoxazolyl group, a benzisoxazolyl group, a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, an imidazolidinyl group, a thiazolinyl group, a sulfolanyl, group, a carbazolyl group, a dibenzofuryl group, a dibenzothienyl group, and a pyridoindolyl group. Preferred examples thereof are a pyridyl group, a pyrimidinyl group, an imidazolyl group, and a thienyl group, and more preferred examples are a pyridyl group and a pyrimidinyl group.
RT1 to RT7, and R′ are preferably a hydrogen atom, an alkyl group, a cyano group, a trifluoromethyl group, a perfluoroalkyl group, a dialkylamino group, a fluoro group, an aryl group, or a heteroaryl group, more preferably a hydrogen atom, an alkyl group, a cyano group, a trifluoromethyl group, a fluoro group, or an aryl group, and still more preferably a hydrogen atom, an alkyl group, or an aryl group. The substituent Z is preferably an alkyl group, an alkoxy group, a fluoro group, a cyano group, or a dialkylamino group, and more preferably a hydrogen atom.
Any two of RT1 to RT7, and R′ may be bonded to each other to form a fused 4- to 7-membered ring, the fused 4- to 7-membered ring is cycloalkyl, aryl, or heteroaryl, and the fused 4- to 7-membered ring may further have a substituent Z. The definitions and the preferred ranges of the formed cycloalkyl, aryl, and heteroaryl are the same as the cycloalkyl group, the aryl group, and the heteroaryl group defined in RT1 to RT7, and R′.
Further, a case where A represents CR′ and 0 to 2 members of RT1 to RT7, and R′ is/are an alkyl group or a phenyl group and the remainders are all hydrogen atoms is particularly preferred, and a case where 0 to 2 members of RT1 to RT7, and R′ is/are an alkyl group and the remainders are all hydrogen atoms is particularly preferred.
nE3 is preferably 2 or 3. With regard to the kind of the ligands in the complex, the ligands are preferably constituted of one or two kinds, and more preferably constituted of one kind. When a reactive group is introduced to the complex molecule, the ligand preferably includes two kinds from the viewpoint of easy synthesis.
(X—Y) has the same definition as (X—Y) in the general formula (E-1) and the preferred range thereof is also the same.
One of preferred embodiments of the compound represented by the general formula (E-3) is a compound represented by the following general formula (E-4).
In the general formula (E-4), RT1 to RT4, A, (X—Y) and nE4 have the same definitions as RT1 to RT4, A, (X—Y) and nE3 in the general formula (E-3), and the preferred ranges thereof are also the same. R1′ to R5′ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, —CN, a perfluoroalkyl group, a trifluorovinyl group, —CO2R, —C(O)R, —NR2, —NO2, —OR, a halogen atom, an aryl group, or a heteroaryl group. Further, they may have a substituent Z. Rs each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
Any two of R1′ to R5′ may be bonded to each other to form a fused 4- to 7-membered ring, the fused 4- to 7-membered ring is cycloalkyl, aryl, or heteroaryl, and the fused 4- to 7-membered ring may further have a substituent Z.
Zs each independently represent a halogen atom, —R″, —OR″, —N(R″)2, —SR″, —C(O) R″, —C(O) OR″, —C(O) N(R″)2, —CN, —NO2, —SO2, —SOR″, —SO2R″, or —SO3R″, and R″s each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
In addition, the preferred ranges of R1′ to R5′ are the same as those of RT1 to RT7, and R′ in general formula (E-3). Further, a case where A represents CR′ and, 0 to 2 members of RT1 to RT4, R′, and R1′ to R5′ represent(s) an alkyl group or a phenyl group, and the remainders are all hydrogen atoms is particularly preferred, and a case where 0 to 2 members of RT1 to RT4, R′, and R1′ to R5′ is/are alkyl groups, and the remainders are all hydrogen atoms is still more preferred.
Preferred specific examples of the compound represented by the general formula (E-1) are listed below, but the compounds not limited thereto.
The compound exemplified as the compound represented by the general formula (E-1) can be synthesized by various methods described in JP-A-2009-99783, U.S. Pat. No. 7,279,232, and the like. After the synthesis, the compound is preferably purified by column chromatography, recrystallization, or the like, and then purified by sublimation purification. By sublimation purification, it is possible not only to separate organic impurities but also to effectively remove the inorganic salts, remaining solvent, or the like.
Although the phosphorescent light emitting material is preferably contained in the light emitting layer, the use thereof is not limited, and further, the phosphorescent light emitting material may also be contained in any further layer of the organic layers.
The phosphorescent light emitting material in the light emitting layer is preferably contained in the light emitting layer generally in an amount of 0.1% by mass to 50% b y mass with respect to the total mass of the compounds forming the light emitting layer, and from the viewpoint of durability and external quantum efficiency, the phosphorescent light emitting material is more preferably contained in an amount of 1% by mass to 50% by mass, and particularly preferably contained in an amount of 2% by mass to 40% by mass.
(3) Other Host Materials
Host materials, which can be used in the light emitting layer, other than the compound represented by the general formula (1) include a compound having the following structure as a partial structure:
conductive high-molecular oligomers such as aromatic hydrocarbon, pyrrole, indole, carbazole, azaindole, indolocarbazole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, hydrazone, stilbene, silazarie, an aromatic tertiary amine compound, a styrylamine compound, a porphyrin-based compound, a polysilane-based compound, a poly(N-viriylcarbazole), an aniline-based copolymer, a thiophene oligomer, and a polythiophene, organic silane, a carbon film, pyridine, pyrimidine, triazine, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, a fluorine-substituted aromatic compound, heterocyclic tetracarboxylic anhydride such as naphthalene perylene, phthalocyanine, and various metal complexes typified by metal complexes of 8-quinolinol derivatives and metal complexes having metal phthalocyanine, benzoxazole, or benzothiazole as a ligand thereof, and derivatives thereof (which may have a substituent or a fused ring), and the like.
(Other Layers)
The organic electroluminescent element of the present invention may include layers other than the light emitting layer.
Examples of the organic layer other than the light emitting layer which may be included in the organic layer include a hole injecting layer, a hole transporting layer, a blocking layer (a hole blocking layer, an electron blocking layer, an exciton blocking layer, and the like), and an electron transporting layer. Specific examples of the layer configuration include those described below, but the present invention is not limited to these configurations.
The organic electroluminescent element of the present invention preferably includes at least one (A) organic layer which is preferably disposed between the anode and the light emitting layer. Examples of the (A) organic layer which is preferably disposed between the anode and the light emitting layer include an hole injecting layer, a hole transporting layer, and an electron blocking layer from the anode side.
The organic electroluminescent element of the present invention preferably includes at least one (B) organic layer which is preferably disposed between the cathode and the light emitting layer. Examples of the (B) organic layer which is preferably disposed between the cathode and the light emitting layer include an electron injecting layer, an electron transporting layer, and a hole blocking layer from the cathode side.
Specifically, an example of the preferred embodiments of the organic electroluminescent element according to the present invention is the embodiment shown in
Hereinafter, the layers other than the light emitting layer which the organic electroluminescent element of the present invention may have will be described.
(A) Organic Layer Preferably Disposed Between Anode and Light Emitting Layer
First, the (A) organic layer preferably disposed between the anode and the light emitting layer will be described.
(A-1) Hole Injecting Layer and Hole Transporting Layer
The hole injecting layer and the hole transporting layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. The hole injecting material and the hole transporting material used in these layers may be either a low molecular compound or a high molecular compound.
For the hole injecting layer and the hole transporting layer, the matters described in paragraph Nos. [0165] to [0167] of JP-A-2008-270736 can be applied to the present invention.
The hole injecting layer preferably contains an electron receiving dopant. By incorporating the electron receiving dopant into the hole injecting layer, for example, there are brought such effects that the hole injecting properties are enhanced, that the driving voltage is lowered, and that the efficiency is enhanced. The electron receiving dopant may be any one of organic materials or inorganic materials so long as the material is capable of withdrawing electrons from the material to be doped and generating radical cations, and examples thereof include a TCNQ compound such as tetracyanoquinodimethane (TCNQ) and tetrafluorotetracyanoquinodimethane (F4-TCNQ), a hexaazatriphenylene compound such as hexacyanohexaazatriphenylene (HAT-CN, a compound LG 101 used in Examples as described later), and molybdenum oxide. By interposing only the electron receiving dopant above, as a thin film, between the anode and the hole transporting layer, the same effect can be provided. In this case, this layer is referred to as a hole injecting layer. In addition, also by interposing the electron receiving dopant, as a thin film, between hole transporting layers, the same effect can be provided. In this case, one hole injecting layer or multiple hole injecting layers may be interposed between the hole transporting layers.
The electron receiving dopant in the hole injecting layer is preferably contained in an amount of 0.01% by mass to 50% by mass, more preferably in an amount of 0.1% by mass to 40% by mass, and more preferably in an amount of 0.2% by mass to 30% by mass, with respect to the total mass of the compounds forming the hole injecting layer. In the case of being used as a thin film, the thickness of the hole injecting layer is preferably from 1 nm to 50 nm, more preferably from 3 nm to 30 nm, and still more preferably from 5 nm to 20 nm.
(A-2) Electron Blocking Layer
The electron blocking layer is a layer having a function of preventing the electrons, which have been transported from the cathode side to the light emitting layer, from passing through to the anode side. In the present invention, the electron blocking layer can be provided as an organic layer adjacent to the light emitting layer and the anode side.
As the organic compound constituting the electron blocking layer, for example, those exemplified above as the hole transporting material can be used.
The thickness of the electron blocking layer is preferably from 1 nm to 500 nm, more preferably from 3 nm to 200 nm, and still more preferably from 5 nm to 100 nm.
The electron blocking layer may have either a single layer structure composed of one kind or two or more kinds of materials selected from the above-exemplified materials or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
In order to inhibit energy transfer of excitons generated in the light emitting layer to prevent degradation of luminous efficiency, T1 energy in the film state of the organic compound constituting the electron blocking layer is preferably higher than the T1 energy of the light emitting material.
(A-3) Material Particularly Preferably Used in Organic Layer Preferably Disposed Between Anode and Light Emitting Layer
[Compound Represented by General Formula (M-1)]
In the organic electroluminescent element of the present invention, as a material particularly preferably used in (A) the organic layer preferably disposed between the anode and the light emitting layer, at least one compound represented by the following general formula (M-1) may be exemplified.
The compound represented by the general formula (M-1) is preferably contained in an organic layer that is located between the light emitting layer and the anode and adjacent to the light emitting layer. The use thereof is however not limited and the compound may further be contained in any layer of the organic layers. The layer into which the compound represented by the general formula (M-1) is introduced may be any one of a light emitting layer, a hole injecting layer, a hole transporting layer, an electron transporting layer, an electron injecting layer and a charge blocking layer, or the compound may be contained in a plurality of layers thereof.
The organic layer that is located between the light emitting layer and the anode and adjacent to the light emitting layer into which the compound represented by the general formula (M-1) is contained is more preferably an electron blocking layer or a hole transporting layer.
In the general formula (M-1), Ar1 and Ar2 each independently represent alkyl, aryl, heteroaryl, arylamino, alkylamino, morpholino, thiomorpholino, a 5- or 6-membered heterocycloalkyl containing one or more heteroatoms selected from N, O, and S, or a cycloalkyl, and may further have a substituent Z. Ar1 and Ar2 may be bonded to each other via a single bond, alkylene, or alkenylene (regardless of presence or absence of a fused ring) to form a fused 5- to 9-membered ring.
Ar3 represents P-valent alkyl, aryl, heteroaryl or arylamino, and may further have a substituent Z.
Zs each independently represent a halogen atom, —R″, —OR″, —N(R″)2, —SR″, —C(O)R″, —C(O) OR″, —C(O) N(R″)2, —CN, —NO2, —SO2, —SOR″, —SO2R″, or —SO3R″, and R″s each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group.
p is an integer of 1 to 4, and when p is 2 or more, Ar1s and Ar2s may be the same as or different from each other, respectively.
Another preferred embodiment of the compound represented by the general formula (M-1) is a case where the compound is represented by the general formula (M-2).
In the general formula (M-2), RM1 represents an alkyl group, an aryl group, or a heteroaryl group.
RM2 to RM23 each independently represent a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, an alkoxy group, an aryloxy group, an amino group, a silyl group, a cyano group, a nitro group, or a fluorine atom.
In the general formula (M-2), RM1 represents an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms), and these groups may have the above-described substituent Z. RM1 is preferably an aryl group or a heteroaryl group, and more preferably an aryl group. Examples of a preferred substituent in the case where the aryl group of RM1 has a substituent include an alkyl group, a halogen atom, a cyano group, an aryl group and an alkoxy group, more preferably an alkyl group, a halogen atom, a cyano group, or an aryl group, and still more preferably an alkyl group, a cyano group, or an aryl group. The aryl group of RM1 is preferably a phenyl group which may have a substituent Z, and more preferably a phenyl group which may have an alkyl, group or a cyano group.
RM2 to R23 each independently represent a hydrogen atom, an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), a heteroaryl group (preferably having 4 to 12 carbon atoms), an alkoxy group (preferably having 1 to 8 carbon atoms), an aryloxy group (preferably having 6 to 30 carbon atoms), an amino group (preferably having 0 to 24 carbon atoms), a silyl group (preferably having 0 to 18 carbon atoms), a cyano group, a nitro group, or a fluorine atom, and these groups may have the above-described substituent Z.
RM2, RM7, RM8, RM15, RM16 and RM23 are each preferably a hydrogen atom, or an alkyl group or an aryl group which may have a substituent Z, and more preferably a hydrogen atom.
RM4, RM5, RM11, RM12, RM19 and RM20 are each preferably a hydrogen atom, an alkyl group or an aryl group which may have a substituent Z, or a fluorine atom, and more preferably a hydrogen atom.
RM3, RM6, RM9, RM14, RM17, and RM22 are each preferably a hydrogen atom, an alkyl group or an aryl group which may have a substituent Z, a fluorine atom, or a cyano group, more preferably a hydrogen atom or an alkyl group which may have a substituent Z, and still more preferably a hydrogen atom.
RM10, RM13, RM18 and RM21 are each preferably a hydrogen atom, an alkyl group, an aryl group, a heteroaryl group, or an amino group which may have a substituent Z, a nitro group, a fluorine atom, or a cyano group, more preferably a hydrogen atom, an alkyl group, or an aryl group which may have a substituent Z, a nitro group, a fluorine atom, or a cyano group, and still more preferably a hydrogen atom or an alkyl group which may have a substituent Z. As the substituent in the case where the alkyl group has a substituent, a fluorine atom is preferred, and the carbon number in the alkyl group that may have a substituent Z is preferably from 1 to 6, and more preferably from 1 to 4.
In another preferred embodiment, the compound represented by the general formula (M-1) is represented by the following general formula (M-3).
In the general formula (M-3), RS1 to RS5 each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, —CN, a perfluoroalkyl group, a trifluorovinyl group, —CO2R, —C(O)R, —NR2, —NO2, —OR, a halogen atom, an aryl group, or a heteroaryl group, and may further have a substituent Z. Rs each independently represent a hydrogen atom, an alkyl group, a perhaloalkyl group, an alkenyl group, an alkynyl group, a heteroalkyl group, an aryl group, or a heteroaryl group. When a plurality of RS1 to RS5 exist, those groups may be bonded to each other to form a ring, and may further have a substituent Z.
a represents an integer of 0 to 4, and when a plurality of RS1s exist, the RS1s may be the same as or different from one another, and may be bonded to each other to form a ring. b to e each independently represent an integer of 0 to 5, and when a plurality of groups exist for each RS2 to RS5, the groups may be the same as or different from one another, and any two thereof may be bonded to each other to form a ring.
q is an integer of 1 to 5, and when q is 2 or more, a plurality of RS1s may be the same as or different from one another, and may be bonded to each other to form a ring.
The alkyl group may have a substituent, and may be saturated or unsaturated, and as the group that may be the substituent, the above-described Z may be exemplified. The alkyl group represented by RS1 to RS5 is preferably an alkyl group having a total carbon number of 1 to 8, and more preferably an alkyl group having a total carbon number of 1 to 6, and examples thereof include a methyl group, an ethyl group, an i-propyl group, a cyclohexyl group, and a t-butyl group.
The cycloalkyl group may have a substituent, and may be saturated or unsaturated, and as the group that may be the substitute, the above-described substituent Z may be exemplified. The cycloalkyl group represented by RS1 to RS5 is preferably a cycloalkyl group having 4 to 7 ring members, and more preferably a cycloalkyl group having a total carbon number of 5 to 6, and examples thereof include a cyclopenthyl group and a cyclohexyl group.
The alkenyl group represented by RS1 to RS5 preferably has 2 to 30 carbon atoms, more preferably has 2 to 20 carbon atoms, and particularly preferably has 2 to 10 carbon atoms, and examples thereof include vinyl, allyl, 1-propenyl, 1-isopropenyl, 1-butenyl, 2-butenyl, and 3-pentenyl.
The alkynyl group represented by RS1 to RS5 has 2 to 30 carbon atoms, more preferably has 2 to 20 carbon atoms, and particularly preferably has 2 to 10 carbon atoms, and examples thereof include ethynyl, propargyl, 1-propynyl, and 3-pentynyl.
The perfluoroalkyl group represented by RS1 to RS5 includes a group obtained by substituting all the hydrogen atoms in the above-mentioned alkyl group with fluorine atoms.
The aryl group represented by RS1 to RS5 is preferably a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and examples thereof include a phenyl group, a tolyl group, a biphenyl group, and a terphenyl group.
The heteroaryl group represented by RS1 to RS5 is preferably a heteroaryl group having 5 to 8 carbon atoms, more preferably a substituted or unsubstituted 5- or 6-membered heteroaryl group, and examples thereof include a pyridyl group, a pyrazinyl group, a pyridazinyl group, a pyrimidinyl group, a triazinyl group, a quinolinyl group, an isoquinolinyl group, a quinazolinyl group, a cinnolinyl group, a phthalazinyl group, a quinoxalinyl group, a pyrrolyl group, an indolyl group, a furyl group, a benzofuryl group, a thienyl group, a benzothienyl group, a pyrazolyl group, an imidazolyl group, a benzimidazolyl group, a triazolyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, a benzothiazolyl group, an isothiazolyl group, a benzisothiazolyl group, a thiadiazolyl group, an isoxazolyl group, a benzisoxazolyl group, a pyrrolidinyl group, a piperidinyl group, a piperazinyl group, an imidazolidinyl group, a thiazolinyl group, a sulfolanyl group, a carbazolyl group, a dibenzofuryl group, a dibenzothienyl group, and a pyridoindolyl group. Preferred examples thereof are a pyridyl group, a pyrimidinyl group, an imidazolyl group, and a thienyl group, and more preferred examples thereof are a pyridyl group and a pyrimidinyl group.
RS1 to RS5 are each preferably a hydrogen atom, an alkyl group, a cyano group, a trifluoromethyl group, a perfluoroalkyl group, a dialkylamino group, a fluoro group, an aryl group, or a heteroaryl group, more preferably a hydrogen atom, an alkyl group, a cyano group, a trifluoromethyl group, a fluoro group, or an aryl group, and still more preferably a hydrogen atom, an alkyl group, or an aryl group. The substituent Z is preferably an alkyl group, an alkoxy group, a fluoro group, a cyano group, or a dialkylamino group, and more preferably a hydrogen atom or an alkyl group.
Any two of RS1 to RS5 may be bonded to each other to form a fused 4- to 7-membered ring, the fused 4- to 7-membered ring is cycloalkyl, aryl, or heteroaryl, and the fused 4- to 7-membered ring may further have a substituent Z. The definitions and the preferred ranges of the formed cycloalkyl, aryl and heteroaryl are the same as the cycloalkyl group, the aryl group, and the heteroaryl group defined in RS1 to RS5.
In the case where the compound represented by the general formula (M-1) is used in a hole transporting layer, the compound represented by the general formula (M-1) is preferably contained in an amount of 50% by mass to 100% by mass, more preferably contained in an amount of 80% by mass to 100% by mass, and particularly preferably contained in an amount of 95% by mass to 100% by mass.
In addition, in the case where the compound represented by the general formula (M-1) is used in a plurality of organic layers, the compound is preferably contained in each layer within the above range.
Only one kind of the compound represented by the general formula (M-1) may be contained, in any one of organic layers, or a plurality of compounds represented by the general formula (M-1) may be contained in combination of any proportion thereof.
The thickness of the hole transporting layer containing the compound represented by the general formula (M-1) is preferably from 1 nm to 500 nm, more preferably from 3 nm to 200 nm, and still more preferably from 5 nm to 100 nm. In addition, the hole transporting layer is preferably provided in contact with the light emitting layer.
The minimum excited triplet (T1) energy in the film state of the compound represented by the general formula (M-1) is preferably from 1.77 eV (40 kcal/mol) to 3.51 eV (81 kcal/mol), and more preferably from 2.39 eV (55 kcal/mol) to 3.25 eV (75 kcal/mol). In the organic electroluminescent element of the present invention, it is preferable that T1 energy of the compound represented by the general formula (M-1) be more than T1 energy of the above-mentioned phosphorescent light emitting material, from the viewpoint of luminous efficiency. In particular when the luminescent color from the organic electroluminescent element is green (the light emission peak wavelength is from 490 nm to 580 nm), from the viewpoint of luminous efficiency, T1 energy is more preferably from 2.39 eV (55 kcal/mol) to 2.82 eV (65 kcal/mol).
The hydrogen atoms constituting the general formula (M-1) include hydrogen isotopes (deuterium and the like). In this case, all the hydrogen atoms in the compound may be substituted with the hydrogen isotope atoms, or the compound may be a mixture in which a part of the compound contains hydrogen isotopes.
The compound represented by the general formula (M-1) can be synthesized by combining various known synthetic methods. Most commonly, for the carbazole compound, a synthetic method may be exemplified in which a fused compound of an arylhydradine and a cyclohexane derivative is subjected to the Aza-Cope rearrangement reaction, and thereafter converted into an aromatic compound by dehydrogenating (written by L. F. Tieze and Th. Eicher, translated by Takano and Ogasawara, Seimitsu Yuuki Gousei, p. 339 (Nankodo Co., Ltd.)). For a coupling reaction of the resulting carbazole compound with a halogenated aryl compound using a palladium catalyst, a method is exemplified which is described in Tetrahedron Letters, vol. 39, p. 617 (1998), vol. 39, p. 2367 (1998), vol. 40, p. 6393 (1999), and the like. The reaction temperature and the reaction time are not particularly limited and the conditions described in the above documents may be applied.
The compound represented by the general formula (M-1) is preferably formed into a thin film by a vacuum vapor deposition process, but a wet process such as a solution coating can be suitably used. The molecular weight of the compound is preferably 2000 or less, more preferably 1200 or less, and particularly preferably 800 or less, from the viewpoint of deposition suitability and solubility. In terms of the deposition suitability, too small molecular weight causes decrease of the vapor pressure, thereby inhibiting the conversion from the vapor phase to the solid phase, so that it become difficult to form the organic layer. Accordingly, the molecular weight is preferably 250 or more, and particularly preferably 300 or more.
Specific examples of the compound represented by the general formula (M-1) are shown below, but the present invention is not limited thereto.
(B) Organic Layer Preferably Disposed Between Cathode and Light Emitting Layer
Next, the (B) organic layer preferably disposed between the cathode and the light emitting layer will be described.
(B-1) Electron Injecting Layer and Electron Transporting Layer
The electron injecting layer and the electron transporting layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. The electron injecting material and the electron transporting material used in these layers may be either a low-molecular compound or a high-molecular compound.
As the electron transporting material, the compound represented by the general formula (1) can be used. As other electron transporting materials, any one of compounds selected from pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, benzimidazole derivatives, imidazopyridine derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyranedioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, aromatic ring tetracarboxylic acid anhydrides of naphthalene and perylene, phthalocyanine derivatives, various metal complexes typified by metal complexes of 8-quinolinol derivatives, metal phthalocyanine and metal complexes having benzoxazole or benzothiazole as a ligand thereof, organic silane derivatives typified by silole, and hydrocarbon compounds with fused rings such as naphthalene, anthracene, phenanthrene, triphenylene, and pyrene is preferred, and any one of compounds selected from pyridine derivatives, benzimidazole derivatives, imidazopyridine derivatives, metal complexes, and hydrocarbon compounds with fused rings are more preferred.
From the viewpoint of decreasing the driving voltage, the thickness of each of the electron injecting layer and the electron transporting layer is preferably 500 nm or less.
The thickness of the electron transporting layer is preferably from 1 nm to 500 nm, more preferably from 5 nm to 200 nm, and still more preferably from 10 nm to 100 nm. In addition, the thickness of the electron injecting layer is preferably from 0.1 nm to 200 nm, more preferably from 0.2 nm to 100 nm, and still more preferably from 0.5 nm to 50 nm.
The electron injecting layer and the electron transporting layer may have either a single layer structure composed of one kind or two or more kinds of materials selected from the above-exemplified materials or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The electron injecting layer preferably contains an electron donating dopant. By incorporating the electron donating dopant into the electron injecting layer, for example, there are brought such effects that the electron injecting properties are enhanced, that the driving voltage is lowered, and that the efficiency is enhanced. The electron donating dopant may be any one of organic materials and inorganic materials as long as it is capable of giving electrons to the material to be doped to generate radical anions. Examples thereof include dihydroimidazole compounds such as tetrathiafulvalene (TTF), tetrathianaphthacene (TTT), and bis-[1,3-diethyl-2-methyl-1,2-dihydrobenzimidazolyl], lithium, and cesium.
The electron donating dopant in the electron injecting layer is contained in the amount of preferably from 0.01% by mass to 50% by mass, more preferably from 0.1% by mass to 40% by mass, and still more preferably from 0.5% by mass to 30% by mass, with respect to the total mass of the compounds forming the electron injecting layer.
(B-2) Hole Blocking Layer
The hole blocking layer is a layer having a function of preventing holes, which have been transported from the anode side to the light emitting layer, from passing through to the cathode side. In the present invention, the hole blocking layer can be provided as an organic layer adjacent to the light emitting layer on the cathode side.
In order to inhibit the energy transfer of excitons generated in the light emitting layer to prevent degradation of luminous efficiency, T1 energy in the film state of the organic compound constituting the hole blocking layer is preferably higher than the T1 energy of the light emitting material.
As an example of the organic compound constituting the hole blocking layer, for example, the compound represented by the general formula (1) can be used.
Examples of the organic compounds constituting the hole blocking layer, other than the compound represented by the general formula (1), include aluminum complexes such as aluminum (III) tris-8-hydroxyquinoline (abbreviated as Alq) and aluminum (III) bis(2-methyl-8-quinolinato) 4-phenylphenolate (abbreviated as Balq), triazole derivatives, and phenanthroline derivatives such as 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (abbreviated as BCP). In the present invention, the function of the hole blocking layer is not limited to the function of actually blocking the holes, and the hole blocking layer may have a function to prevent the excitons in the light emitting layer from diffusing to the electron transporting layer, or a function to block energy transfer quenching. The compound of the present invention can be preferably applied to the hole blocking layer.
The thickness of the hole blocking layer is preferably from 1 nm to 500 nm, more preferably from 3 nm to 100 nm, and still more preferably from 5 nm to 50 nm.
The hole blocking layer may have either a single layer structure composed of one kind or two or more kinds of materials selected from the above-exemplified materials or a multilayer structure composed of a plurality of layers having the same composition or different compositions.
The material which is used in the hole blocking layer preferably has higher T1 energy than that of the phosphorescent light emitting material in view of color purity, luminous efficiency, and driving durability.
(B-3) Material Particularly Preferably Used in Organic Layer which is Preferably Disposed Between Cathode and Light Emitting Layer
For the organic electroluminescent element of the present invention, examples of the material which is particularly preferably used in the materials for the (B) organic layer which is preferably disposed between the cathode and the light emitting layer include the compound represented by the general formula (1), an aromatic hydrocarbon compound (in particular, a compound represented by the following general formula (Tp-1)), and a compound represented by the following general formula (O-1).
The aromatic hydrocarbon compound and a compound represented by the general formula (O-1) will be described below.
[Aromatic Hydrocarbon Compound]
The aromatic hydrocarbon compound is preferably contained in an organic layer that is located between the light emitting layer and the cathode and adjacent to the light emitting layer, but is not limited in the use and may be further contained in any layer of the organic layers. The layer into which the aromatic hydrocarbon compound is introduced is anyone of a light emitting layer, a hole injecting layer, a hole transporting layer, an electron transporting layer, an electron injecting layer, an exciton blocking layer, and a charge blocking layer, or the compound may be contained in a plurality of layers.
The organic layer that is located between the light emitting layer and the cathode and adjacent to the light emitting layer, into which the aromatic hydrocarbon compound is contained, is preferably a blocking layer (a hole blocking layer or an exciton blocking layer) or an electron transporting layer, and more preferably an electron transporting layer.
In the case where the aromatic hydrocarbon compound is contained in a layer other than the light emitting layer, the compound is preferably contained in an amount of 70% by mass to 100% by mass, and more preferably 85% by mass to 100% by mass. In the case where the aromatic hydrocarbon compound is contained in the light emitting layer, the compound is preferably contained in an amount of 0.1% by mass to 99% by mass, more preferably contained in an amount of 1% by mass to 95% by mass, and more preferably contained in an amount of 10% by mass to 95% by mass, with respect to the total mass of the light emitting layer.
As the aromatic hydrocarbon compound, a hydrocarbon compound which has a molecular weight of 400 to 1200 and has a fused polycyclic skeleton having a total carbon number of 13 to 22 is preferably used. The fused polycyclic skeleton having a total carbon number of 13 to 22 is preferably any one of fluorene, anthracene, phenanthrene, tetracene, chrysene, pentacene, pyrene, perylene, and triphenylene, more preferably from the viewpoint of the T1, a fluorene, triphenylene, and phenanthrene, still more preferably from the viewpoint of compound stability and electron injecting and transporting properties, triphenylene, and particularly preferably a compound represented by the following general formula (Tp-1).
The hydrocarbon compound represented by the general formula (Tp-1) has a molecular weight of preferably 400 to 1200, more preferably 400 to 1100, and still more preferably 400 to 1000. When the molecular weight is 400 or more, an amorphous thin film of good quality can be formed, and the molecular weight of 1200 or less is preferred in terms of solubility in a solvent and applicability to sublimation and deposition suitability.
The hydrocarbon compound represented by the general formula (Tp-1) is not limited in the use, and may be contained not only in the organic layer adjacent to the light emitting layer but in any layer in the organic layers.
In the general formula (Tp-1), R12 to R23 each independently represent a hydrogen atom, an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (these groups may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), provided that not all of R12 to R23 are a hydrogen atom.
Examples of the alkyl group represented by R12 to R23 include a methyl group, an ethyl group, an isopropyl group, an n-butyl group, a tert-butyl group, an n-octyl group, an n-decyl group, an n-hexadecyl group, a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group, preferably a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, and a cyclohexyl group, and more preferably a methyl group, ethyl group, and a tert-butyl group, each of which may be substituted or unsubstituted.
R1 to R2 may be each preferably substituted with an alkyl group having 1 to 4 carbon atoms, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), and still more preferably a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group.
R12 to R23 are each particularly preferably a benzene ring which may be substituted with a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group).
The total number of the aryl rings in the general formula (Tp-1) is preferably from 2 to 8, and more preferably from 3 to 5. When the aryl ring number is within this range, it is possible to form an amorphous thin film of high quality and to achieve good solubility in a solvent, applicability to sublimation, and deposition suitability.
R12 to R23 preferably each independently have a total carbon number of 20 to 50, and more preferably a total carbon number of 20 to 36. When the total carbon number is within this range, it is possible to form an amorphous thin film of high quality and to achieve good solubility in a solvent, applicability to sublimation, and deposition suitability.
The hydrocarbon compound represented by the general formula (Tp-1) is preferably a hydrocarbon compound represented by the following general formula (Tp-2).
In the general formula (Tp-2), a plurality of Ar11s are the same, and each represent an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (these groups may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group).
The hydrogen atom, the alkyl group, the phenyl group, the fluorenyl group, the naphthyl group, or the triphenylenyl group represented by Ar11 (these groups may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group) has the same definitions as enumerated for R12 to R23, and preferred ones are also the same.
The hydrocarbon compound represented by the general formula (Tp-1) is also preferably a hydrocarbon compound represented by the following general formula (Tp-3).
In the general formula (Tp-3), L represents an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (these groups may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), or an n-valent linking group formed by a combination thereof. n represents an integer of 2 to 6.
The alkyl group, the phenyl group, the fluorenyl group, the naphthyl group, or the triphenylenyl group, which forms the n-valent linking group represented by L, has the same definitions as enumerated for R12 to R23.
L is preferably an n-valent linking group formed of a benzene ring or a fluorene ring which may be substituted by an alkyl group or a benzene ring, or a combination thereof.
Specific preferred examples of L are listed below, but L is not limited thereto. In the specific examples, the group is bonded at * to a triphenylene ring.
n is preferably from 2 to 5, and more preferably from 2 to 4.
The compound represented by the general formula (Tp-1) is preferably a compound represented by the following general formula (Tp-4)
(In the general formula (Tp-4), AA1 to AA12 each independently represent CR400 or a nitrogen atom. n401 represents an integer of 0 to 8. In the case where n401 is 0, the ring represented by AA1 to AA6 represents a single bond between the triphenylene ring and the ring represented by AA7 to AA12. In the case where n401 is from 2 to 6, a plurality of rings represented by AA1 to AA6 may be different for each appearance, and a plurality of linking modes between the rings may be different for each appearance.)
Incidentally, in the present invention, the hydrogen atoms in the description of the general formula (Tp-4) include isotopes (a deuterium atom and the like), and any atoms constituting the further substituent also include the isotopes thereof.
In the general formula (Tp-4), R411 to R421 each independently represent a hydrogen atom, an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group).
R411 to R421 are each preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), more preferably a hydrogen atom or a phenyl group (the phenyl group may be substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), and particularly preferably a hydrogen atom.
A1 to A12 are each preferably CR400.
In the general formula (Tp-4), the substituent represented by R400 preferably represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group). A plurality of R400s may be different from each other.
Preferably, R400 is preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group (which may be further substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), more preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group (the phenyl group may be substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group), and particularly preferably a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a phenyl group (the phenyl group may be substituted with an alkyl group, a phenyl group, a fluorenyl group, a naphthyl group, or a triphenylenyl group).
n401 is preferably an integer of 0 to 5, more preferably an integer of 1 to 5, and particularly preferably 2 to 4.
n401 is an integer of 1 or more, and in the case where the linking position to the ring represented by AA7 to A12 is AA3, from the viewpoint of luminous efficiency, the substituent represented by AA4 or AA5 is CR400, and R400 is preferably an alkyl group having 1 to 4 carbon atoms or a phenyl group, more preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group.
In the general formula (Tp-4), among the 6-membered aromatic rings constituted of AA1 to AA12 the number of the ring containing a nitrogen atom is preferably at most one, and more preferably zero. In the general formula (Tp-4), the connection of the 6-membered aromatic rings constituted of A1 to AA2 has no restriction, but the rings preferably are connected on meta- or para-positions. Further, with regard to the compound represented by the general formula (Tp-4), the number of the aromatic rings which are sequentially connected on their para-positions is preferably three or less, including the phenyl ring which is a partial structure of the fused ring constituting the triphenylene ring.
In the case where the hydrocarbon compound represented by the general formula (Tp-1) is used in a host material of a light emitting layer or in a charge transporting material of a layer adjacent to the light emitting layer, in an organic electroluminescent element, when the energy gap in the thin film state (in the case of the light emitting material being a phosphorescent light emitting material, which is the minimum excited triplet (T1) energy in the thin film state) is larger than in the light emission material, the quench of the light emission is prevented, which is advantageous in enhancing the efficiency. On the other hand, from the viewpoint of chemical stability of the compound, it is preferable that an energy gap and T1 energy are not too large. The T1 energy in the film state of the hydrocarbon compound represented by the general formula (Tp-1) is preferably from 1.77 eV (40 kcal/mol) to 3.51 eV (81 kcal/mol), and more preferably from 2.39 eV (55 kcal/mol) to 3.25 eV (75 kcal/mol). In the organic electroluminescent element according to the present invention, it is preferable from the viewpoint of luminous efficiency that the T1 energy of the compound represented by the general formula (Tp-1) be more than the T1 energy of the above-mentioned phosphorescent light emitting material. In particular, in the case where the luminescent color from the organic electroluminescent element is green (the light emission peak wavelength is from 490 nm to 580 nm), it is more preferred from the viewpoint of luminous efficiency that the T1 energy is from 2.39 eV (55 kcal/mol) to 2.82 eV (65 kcal/mol).
The T1 energy of the hydrocarbon compound represented by the general formula (Tp-1) can be determined by the same method as in the description of the general formula (1) above.
From the viewpoint of stable operation of the organic electroluminescent element, when being driven at a high temperature, or against the heat generation during the element driving, the glass transition temperature (Tg) of the hydrocarbon compound according to the present invention is preferably from 80° C. to 400° C., more preferably from 100° C. to 400° C., and still more preferably from 120° C. to 400° C.
Specific examples of the hydrocarbon compound represented by the general formula (Tp-1) are listed below, but the hydrocarbon compound used in the present invention is not to be limited thereto.
The compounds exemplified above as the hydrocarbon compound represented by general formula (Tp-1) can be synthesized by the methods described in WO05/013388, WO06/130598, WO09/021107, US2009/0009065, WO09/008311, and WO04/018587.
After the synthesis, it is preferable that the product be purified by column chromatography, recrystallization, and the like, and then purified by sublimation purification. By sublimation purification, it is possible not only to separate the organic impurities but also to effectively remove the inorganic salts, remaining solvent, and the like.
[Compound Represented by General Formula (O-1)]
As a material particularly preferably used for the material of the (B) organic layer which is preferably disposed between the cathode and the light emitting layer, the compound represented by the following general formula (O-1) is preferably used, from the viewpoint of the efficiency and the driving voltage of the organic electroluminescent element. The general formula (O-1) will be described below.
In the general formula (O-1), RO1 represents an alkyl group, an aryl group, or a heteroaryl group. AO1 to AO4 each independently represent C—RA or a nitrogen atom. RA represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and a plurality of RAs may be the same as or different from each other. LO1 represents a divalent to hexavalent linking group composed of an aryl ring or a heteroaryl ring. nO1 represents an integer of 2 to 6.
RO1 represents an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms), which may have the Substituent Group A as described above. RO1 is preferably an aryl group or a heteroaryl group, and more preferably an aryl group. Preferred examples of the substituent in the case where the aryl group of RO1 has a substituent include an alkyl group, an aryl group, and a cyano group. Among them, an alkyl group or an aryl group are more preferred, with an aryl group being still more preferred. In the case where the aryl group of RO1 has a plurality of substituents, a plurality of substituents may be bonded to each other to form a 5- or 6-membered ring. The aryl group of RO1 is preferably a phenyl group which may have the Substituent Group A as described above, more preferably a phenyl group which may be substituted with an alkyl group or an aryl group, and still more preferably an unsubstituted phenyl group or a 2-phenylphenyl group.
AO1 to AO4 each independently represent C—RA or a nitrogen atom. It is preferable that from zero to two of AO1 to AO4 be a nitrogen atom, and it is more preferable that zero or one of AO1 to AO4 be a nitrogen atom. It is preferable that all of AO1 to AO4 be C—RA, and AO1 be a nitrogen atom, and AO2 to AO4 be C—R, it is more preferable that AO1 be a nitrogen atom, and AO2 to AO4 be C—RA, and it is still more preferable that AO1 be a nitrogen atom, AO2 to AO4 be C—RA, and RAs be all a hydrogen atom.
RA represents a hydrogen atom, an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms), and may have the above-mentioned substituent Z′. In addition, a plurality of RAs may be the same as or different from one another. RA is preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.
LO1 represents a divalent to hexavalent linking group composed of an aryl ring (preferably having 6 to 30 carbon atoms) or a heteroaryl ring (preferably having 4 to 12 carbon atoms). LO1 is preferably an arylene group, a heteroarylene group, an aryltriyl group, or a heteroaryltriyl group, more preferably a phenylene group, a biphenylene group, or a benzenetriyl group, and still more preferably a biphenylene group or a benzenetriyl group. LO1 may have the above-mentioned substituent Z′, and in the case where LO1 has a substituent, the substituent is preferably an alkyl group, an aryl group, or a cyano group. Specific examples of LO1 include the following.
nO1 represents an integer of 2 to 6, preferably an integer of 2 to 4, and more preferably 2 or 3. nO1 is most preferably 3 from the viewpoint of efficiency of the organic electroluminescent element, or nO1 is most preferably 2 from the viewpoint of durability of the organic electroluminescent element.
The compound represented by the general formula (O-1) is preferably a compound represented by the following general formula (O-2).
In the general formula (O-2), RO1s each independently represent an alkyl group, an aryl group, or a heteroaryl group. RO2 to RO4 each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group. AO1 to AO4 each independently represent C—RA or a nitrogen atom. RA represents a hydrogen atom, an alkyl group, an aryl group, or a heteroaryl group, and a plurality of RAs may be the same as or different from one another.
RO1 and AO1 to AO4 have the same definitions as RO1 and AO1 to AO4 in the general formula (O-1) described above, and the preferred ranges thereof are also the same.
RO2 to RO4 each independently represent a hydrogen atom, an alkyl group (preferably having 1 to 8 carbon atoms), an aryl group (preferably having 6 to 30 carbon atoms), or a heteroaryl group (preferably having 4 to 12 carbon atoms), and these groups may have a substituent selected from the Substituent Group A described above. RO2 to RO4 are preferably a hydrogen atom, an alkyl group or an aryl group, more preferably a hydrogen atom or an aryl group, and most preferably a hydrogen atom.
The glass transition temperature (Tg) of the compound represented by the general formula (O-1) is preferably from 100° C. to 400° C., more preferably from 120° C. to 400° C., still more preferably from 140° C. to 400° C., from the viewpoint of stability at the time of storage at a high temperature, or stable operation during driving at a high temperature against heat generation during driving.
Specific examples of the compound represented by the general formula (O-1) will be shown below, but the compound used in the present invention is not limited thereto.
The compound represented by the general formula (O-1) can be synthesized by the method described in JP-A-2001-335776. After the synthesis, it is preferable that the product is purified by column chromatography, recrystallization, reprecipitation, and then purified by sublimation purification. By sublimation purification, it is possible not only to separate organic impurities but also to effectively remove inorganic salts, remaining solvent, moisture, or the like.
In the organic electroluminescent element of the present invention, the compound represented by the general formula (O-1) is preferably contained in an organic layer between the light emitting layer and the cathode, and more preferably contained a layer adjacent to the light emitting layer on the cathode side.
<Protective Layer>
In the present invention, the entirety of the organic electroluminescent element may be protected by a protective layer.
For the protective layer, the detailed description in paragraph Nos. [0169] to [0170] of JP-A-2008-270736 can be applied to the present invention. Incidentally, the materials for the protective layer may be either an inorganic material or an organic material.
<Sealing Enclosure>
For the organic electroluminescent element of the present invention, the entirety of the element may be sealed using a sealing enclosure.
For the sealing enclosure, the detailed description in paragraph No. [0171] of JP-A-2008-270736 can be applied to the present invention.
<Driving Method>
The organic electroluminescent element of the present invention can emit light by applying a direct current (it may include an alternate current component, if desired) voltage (usually from 2 volts to 15 volts) or a direct current between the anode and the cathode.
As a driving method of the organic electroluminescent element of the present invention, driving methods described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234685, and JP-A-8-241047, Japanese Patent No. 2784615, and U.S. Pat. Nos. 5,828,429 and 6,023,308 can be applied.
The external quantum efficiency of the organic electroluminescent element of the present invention is preferably 7% or more, and more preferably 10% or more. As for the numerical value of the external quantum efficiency, a maximum value of the external quantum efficiency obtained when the organic electroluminescent element is driven at 20° C., or a value of the external quantum efficiency in the vicinity of from 300 cd/m2 to 400 cd/m2 obtained when the element is driven at 20° C. can be employed.
The internal quantum efficiency of the organic electroluminescent element of the present invention is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more. The internal quantum efficiency of the element is calculated by dividing the external quantum efficiency by the light extraction efficiency. Though the light extraction efficiency in usual organic EL elements is about 20%, by adjusting the shape of a substrate, the shape of an electrode, the film thickness of an organic layer, the film thickness of an inorganic layer, the refractive index of an organic layer, the refractive index of an inorganic layer, or the like, it is possible to increase the light extraction efficiency to 20% or more.
<Light Emitting Wavelength>
The organic electroluminescent element of the present invention has no limitation in its light emitting wavelength, and may be used for red light emission, green light emission, or blue light emission among the three primary colors of light. Above all, the organic electroluminescent element of the present invention preferably have a emission peak wavelength of 400 nm to 700 nm from the viewpoint of luminous efficiency in view of the minimum excision triplet (T1) energy of the compound represented by the general formula (1).
Specifically, in the organic electroluminescent element of the present invention, in the case of using the compound represented by the general formula (1) as a host material of the light emitting layer, or as an electron transporting material of the electron transporting layer or the hole blocking layer, the light emission peak wavelength of the guest material is preferably from 400 nm to 700 nm, more preferably from 450 nm to 650 nm, and particularly preferably from 480 nm to 550 nm.
<Use of Organic Electroluminescent Element of the Present Invention>
The organic electroluminescent element according to the present invention can be suitably used for display elements, displays, backlights, electrophotography, illumination light sources, recording light sources, exposure light sources, readout light sources, signs, billboards, interior decorations, optical communications, and the like. In particular, it is preferably used for devices to be driven in a region of high-intensity luminescence, such as a light emitting device, an illumination device, and a display device.
[Light Emitting Device]
The light emitting device of the present invention may include the organic electroluminescent element of the present invention.
Next, the light emitting device of the present invention will be described with reference to
The organic electroluminescent element 10 is formed by laminating an anode (first electrode) 3, an organic layer 11, and a cathode (second electrode) 9 in this order on a substrate 2. In addition, a protective layer 12 is laminated on the cathode 9, and a sealing enclosure 16 is further provided via an adhesive layer 14 on the protective layer 12. Incidentally, a part of each of the electrodes 3 and 9, a diaphragm, an insulating layer, and the like are omitted.
Here, as the adhesive layer 14, a photocurable adhesive such as an epoxy resin, or a thermosetting adhesive can be used, and for example, a thermosetting adhesive sheet may also be used.
The light emitting device of the present invention is not particularly limited in its use, and it can be used as not only an illumination device but also a display device of a television set, a personal computer, a mobile phone, electronic paper, or the like.
[Illumination Device]
The illumination device of the present invention includes the organic electroluminescent element of the present invention.
Next, the illumination device of the present invention will be described with reference to
The light scattering member 30 is not particularly limited as long as it can scatter light, but in
[Display Device]
The display device of the present invention may include the organic electroluminescent element of the present: invention.
The display device of the present invention may be used for, for example, a display device of a television set, a personal computer, a mobile phone, electronic paper, or the like.
Hereinafter, the characteristic features of the present invention will be described in more detail with reference to Examples. The materials, use amounts, ratios, treatment details, treatment procedures, and the like shown in the following Examples can be appropriately modified so far as the gist of the present invention is not deviated. Accordingly, the scope of the present invention is not limited to the specific examples shown below.
(Synthesis of Compound No O-10-10)
According to the scheme, a compound No O-10-10 was synthesized.
The obtained compound No O-10-10 was subjected to MASS spectrum measurement to check the peaks of [M+H]+.
<Fabrication and Evaluation of Organic Electroluminescent Element>
The organic materials used in the preparation of the organic electroluminescent element were all subjected to sublimation purification. The compounds used in Comparative Examples and Examples are shown below.
Comparative Compound 1: Compound (4-3) described in WO2010/131855
Comparative Compound 2: Compound (1) described in JP-A-2010-087496
Comparative Compound 3: Compound (54) described in JP-A-2010-87496
Comparative Compound 4: Compound (70) described in JP-A-2010-87496
(Fabrication of Anode)
A 0.5 mm-thick and 2.5 cm square glass substrate (manufactured by Geomatec Co., Ltd., surface resistance: 10 Ω/□) having an ITO film thereon was put in a cleaning container. After ultrasonic cleaning in 2-propanol, the glass substrate was subjected to a UV-ozone treatment for 30 minutes.
This was used as an anode (ITO film, transparent anode).
(Lamination of Organic Layers)
On the anode, first to fifth organic layers were sequentially deposited using the following compounds by a vacuum deposition method. The compound structures used in respective layers are shown below together.
First layer: LG101: film thickness: 10 nm
Second layer: NPD: film thickness: 30 nm
Third layer: Comparative Compound 1 (host material) and green phosphorescent light emitting material GD-1 (guest material) (mass ratio: 85:15): film thickness: 30 nm
Fourth layer: TpH-18: film thickness: 10 nm
Fifth layer: Alq: film thickness: 40 nm
(Fabrication of Cathode)
On the above lamination, 0.1 nm of lithium fluoride and 200 nm of metal aluminum were deposited in this order to form a cathode.
(Fabrication of Organic Electroluminescent Element)
A lamination which includes the anode and the cathode, and the five organic layers disposed between the anode and the cathode was placed in a glove box purged with nitrogen gas without contact with atmospheric air, and sealed in a glass sealing can using an ultraviolet cure adhesive (XNR5516HV, manufactured by Nagase-Chiba, Ltd.) to obtain an organic electroluminescent element of Comparative Example 1.
(Evaluation of Organic Electroluminescent Element)
(a) Durability
A DC voltage was applied to the organic electroluminescent element of Comparative Example 1 to allow the element to emit light continuously to attain a luminance of 8000 cd/m2 at room temperature, and the time period required for the luminance to go down to 7200 cd/m2 was measured. This time period was used as an index of the durability of the organic electroluminescent element.
Furthermore, in the respective Tables shown below in the respective Examples and Comparative Examples as described later, the durability at a time of using the organic electroluminescent element of Comparative Example 1 was taken as 100 and the element having a relative value of the durability of less than 100 was rated as “C”, the element having that ranging from 100 to less than 120 as “B”, and the element having that of 120 or more as “A”.
Here, a larger number of durability is more preferred.
(b) Driving Voltage
A DC voltage was applied to the organic electroluminescent element of Comparative Example 1 to allow the element to emit light to attain a luminance of 1000 cd/m2. The voltage applied at this time was used as an index of the evaluation of the driving voltage.
Further, in respective Examples and Comparative Examples as described later, the applied voltage of the organic electroluminescent element of Comparative Example 1 was taken as 100 and the element having a relative value of the voltage of 100 or more was rated as “C”, the element having that ranging from 90 to less than 100 as “B”, and the element having that of less than 90 as “A”. Here, a smaller number of driving voltage is more preferred.
The organic electroluminescent elements in Examples A1 to A14 and Comparative Example 2 were obtained by the same procedure as in Comparative Example 1, except that the compound of the present application or Comparative Compounds 2 to 4 were used instead of Comparative Compound 1 as a material for the third layer in the organic layers.
The durability and the driving voltage of these organic electroluminescent elements were measured by the same method as for the organic electroluminescent element using the Comparative Compound 1 in Comparative Example 1 above, and evaluated in accordance with the measurement criteria as described above. The results are shown in Table 66 below.
The organic electroluminescent element of Comparative Example 5 was fabricated in the same manner as in Comparative Example 1, except that NPD used in the second layer was changed to HTL-1, GD-1 used in the third layer was changed to GD-2, TpH-18 used in the fourth layer was changed to OM-8, and Alq used in the fifth layer was changed to OM-8. The configuration of the organic layers in Comparative Example 5 is shown below.
First layer: LG101, film thickness: 10 nm
Second layer: HTL-1, film thickness: 30 nm
Third layers: Comparative Compound 1 (host material) and green phosphorescent light emitting material GD-2 (guest material) (mass ratio: 85:15), film thickness: 30 nm
Fourth layer: OM-8, film thickness: 10 nm
Fifth layer: OM-8, film thickness: 40 nm
The organic electroluminescent elements of Examples B1 to B14 and Comparative Example 4 were obtained in the same manner as in Comparative Example 5, except that the compound of the present application or Comparative Compound 2 was used instead of Comparative Compound 1 as the material for the third layer in the organic layers.
The durability and the driving voltage of these organic electroluminescent elements were measured by the same method as for the organic electroluminescent element using the Comparative Compound 1 in Comparative Example 1 above, and evaluated in accordance with the measurement criteria as described above. The results are shown in Table 67 below.
The organic electroluminescent element of Comparative Example 9 was fabricated in the same manner as in Comparative Example 1, except that LG101 used in the first layer was changed to GD-1, GD-1 used in the third layer was changed to a red phosphorescent light emitting material RD-1, and TpH-18 used in the fourth layer was changed to Alq. The configuration of the organic layers in Comparative Example 9 is shown below.
First layer: GD-1, film thickness: 10 nm
Second layer: NPD, film thickness: 30 nm
Third layer: Comparative Compound 1 (host material) and red phosphorescent light emitting material RD-1 (guest material) (mass ratio: 90:10), film thickness: 30 nm
Fourth layer: Alq, film thickness: 10 nm
Fifth: Alq, film thickness: 40 nm
The organic electroluminescent elements of Examples C1 to C10 and Comparative Examples 10 to 12 were obtained in the same manner as in Comparative Example 9, except that, as the material for the third layer in the organic layers, the compound of the present application or Comparative Compound 2 was used instead of Comparative Compound 1.
The durability and the driving voltage of these organic electroluminescent elements were measured by the same method as for the organic electroluminescent element using the Comparative Compound 1 in Comparative Example 1 above, and evaluated in accordance with the measurement criteria as described above. The results are shown in Table 68 below.
From Tables 66 to 68 above, it can be seen that the organic electroluminescent element using the host material of the present invention has excellent durability and low driving voltage, which is thus good.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-254821 | Nov 2011 | JP | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14351151 | Jul 2014 | US |
| Child | 17173532 | US |
