JP6020173B2 - Light emitting device material and light emitting device - Google Patents

Description

  The present invention relates to a light emitting element capable of converting electric energy into light. More specifically, the present invention relates to a light emitting element that can be used in fields such as a display element, a flat panel display, a backlight, illumination, interior, a sign, a signboard, an electrophotographic machine, and an optical signal generator.

  In recent years, research on organic thin-film light emitting devices that emit light when electrons injected from a cathode and holes injected from an anode are recombined in an organic phosphor sandwiched between both electrodes has been actively conducted. This light emitting element is characterized by thin light emission with high luminance under a low driving voltage and multicolor light emission by selecting a fluorescent material. This study was conducted by C.D. W. Since Tang et al. Have shown that organic thin-film elements emit light with high brightness, they have been studied by many research institutions.

  In addition, organic thin-film light-emitting elements can be obtained in various light-emitting colors by using various light-emitting materials for the light-emitting layer. Among the three primary color luminescent materials, research on the green luminescent material is the most advanced, and at present, intensive research is being conducted to improve the characteristics of the red and blue luminescent materials.

  The organic thin film light emitting element needs to satisfy the improvement in luminous efficiency, the reduction in driving voltage, and the improvement in durability. In particular, the compatibility between luminous efficiency and durability is a major issue. For example, in order to improve the light emission efficiency and the durability life, a light emitting material and an electron transport material having pyrene as a basic skeleton have been developed (for example, see Patent Documents 1 to 5).

JP 2007-131723 A JP 2007-159591 A JP 2011-14886 A International Publication No. 2004/63159 European Patent Application No. 1808912

  However, as described above, in the organic thin film light emitting device, it has been a long-standing problem to achieve both luminous efficiency and durability, and even if the material group described in the above patent document is used for the electron transport layer, the luminous efficiency and durability are It was insufficient to achieve both.

  An object of the present invention is to provide a light-emitting element that solves the problems of the prior art and enables an organic thin-film light-emitting element having high-efficiency light emission and excellent durability.

  The present invention is a light emitting device material comprising a compound represented by the following general formula (1) or (2).

R ^{1 to} R ¹⁶ may be the same or different from each other, and may be hydrogen, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, alkoxy group, alkylthio group, aryl ether group, aryl thioether. Selected from the group consisting of a group, an aryl group, a heteroaryl group, a halogen, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, a silyl group, and —P (═O) R ¹⁷ R ¹⁸ . R ¹⁷ and R ¹⁸ are an aryl group or a heteroaryl group. R ^{1 to} R ⁸ and R ^{9 to} R ¹⁶ may form a ring with adjacent substituents. X is a group represented by the general formula ( 5 ), and Y is a group represented by the general formula (4). L ¹ represents a single bond, a substituted or unsubstituted arylene group having 6 to 40 nuclear carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 40 nuclear carbon atoms . L ² represents a single bond, a residue derived from a substituted or unsubstituted aryl group having 6 to 14 nuclear carbon atoms, or a residue derived from a substituted or unsubstituted heteroaryl group having 2 to 14 nuclear carbon atoms. HAr ¹ and HAr ² represent a heteroaryl group having a substituted or unsubstituted electron-accepting nitrogen. R ^{19 to} R ²¹ have the same meanings as R ^{1 to} R ¹⁶ . m is 1 when L ² is a single bond, and otherwise represents an integer of 1 to 5 . H Ar ¹ is but it may also be the same or different, respectively. When m is 2 to 5, HAr ² may be the same or different. X and Y are not the same group.

  According to the present invention, it is possible to provide an organic electroluminescence device having high efficiency light emission and excellent durability.

  The compound represented by formula (1) or (2) will be described in detail.

R ^{1 to} R ¹⁶ may be the same or different from each other, and may be hydrogen, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, alkoxy group, alkylthio group, aryl ether group, aryl thioether. Selected from the group consisting of a group, an aryl group, a heteroaryl group, a halogen, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, a silyl group, and —P (═O) R ¹⁷ R ¹⁸ . R ¹⁷ and R ¹⁸ are an aryl group or a heteroaryl group. R ^{1 to} R ⁸ and R ^{9 to} R ¹⁶ may form a ring with adjacent substituents. X is a group represented by the general formula (3), and Y is a group represented by the general formula (4). L ¹ represents a single bond, a substituted or unsubstituted arylene group having 6 to 40 nuclear carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 40 nuclear carbon atoms. Ar ¹ represents a residue derived from a substituted or unsubstituted aryl group having 6 to 14 nuclear carbon atoms, or a residue derived from a substituted or unsubstituted heteroaryl group having 2 to 14 nuclear carbon atoms. L ² represents a single bond, a residue derived from a substituted or unsubstituted aryl group having 6 to 14 nuclear carbon atoms, or a residue derived from a substituted or unsubstituted heteroaryl group having 2 to 14 nuclear carbon atoms. HAr ¹ and HAr ² represent a heteroaryl group having a substituted or unsubstituted electron-accepting nitrogen. n is an integer of 1-5. m is 1 when L ² is a single bond, and otherwise represents an integer of 1 to 5. When n is 2 to 5, HAr ¹ may be the same or different, and when m is 2 to 5, HAr ² may be the same or different. X and Y are not the same group.

  Of these substituents, hydrogen may be deuterium. The alkyl group represents, for example, a saturated aliphatic hydrocarbon group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a tert-butyl group. It may or may not have a substituent. There is no restriction | limiting in particular in the additional substituent in the case of being substituted, For example, an alkyl group, an aryl group, heteroaryl group etc. can be mentioned, This point is common also in the following description. The number of carbon atoms of the alkyl group is not particularly limited, but is usually in the range of 1 to 20 and more preferably 1 to 8 from the viewpoint of availability and cost.

  The cycloalkyl group represents, for example, a saturated alicyclic hydrocarbon group such as a cyclopropyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, which may or may not have a substituent. Although carbon number of an alkyl group part is not specifically limited, Usually, it is the range of 3-20.

  The heterocyclic group refers to an aliphatic ring having atoms other than carbon, such as a pyran ring, a piperidine ring, and a cyclic amide, in the ring, which may or may not have a substituent. . Although carbon number of a heterocyclic group is not specifically limited, Usually, it is the range of 2-20.

  An alkenyl group shows the unsaturated aliphatic hydrocarbon group containing double bonds, such as a vinyl group, an allyl group, and a butadienyl group, and this may or may not have a substituent. Although carbon number of an alkenyl group is not specifically limited, Usually, it is the range of 2-20.

  The cycloalkenyl group refers to an unsaturated alicyclic hydrocarbon group containing a double bond such as a cyclopentenyl group, a cyclopentadienyl group, or a cyclohexenyl group, which may have a substituent. You don't have to.

  An alkynyl group shows the unsaturated aliphatic hydrocarbon group containing triple bonds, such as an ethynyl group, for example, and may or may not have a substituent. Although carbon number of an alkynyl group is not specifically limited, Usually, it is the range of 2-20.

  The alkoxy group refers to, for example, a functional group having an aliphatic hydrocarbon group bonded through an ether bond such as a methoxy group, an ethoxy group, or a propoxy group, and the aliphatic hydrocarbon group may have a substituent. It may not have. Although carbon number of an alkoxy group is not specifically limited, Usually, it is the range of 1-20.

  The alkylthio group is a group in which an oxygen atom of an ether bond of an alkoxy group is substituted with a sulfur atom. The hydrocarbon group of the alkylthio group may or may not have a substituent. Although carbon number of an alkylthio group is not specifically limited, Usually, it is the range of 1-20.

  An aryl ether group refers to a functional group to which an aromatic hydrocarbon group is bonded via an ether bond, such as a phenoxy group, and the aromatic hydrocarbon group may or may not have a substituent. Good. Although carbon number of an aryl ether group is not specifically limited, Usually, it is the range of 6-40.

  An aryl thioether group is one in which the oxygen atom of the ether bond of the aryl ether group is substituted with a sulfur atom. The aromatic hydrocarbon group in the aryl ether group may or may not have a substituent. Although carbon number of an aryl ether group is not specifically limited, Usually, it is the range of 6-40.

  An aryl group shows aromatic hydrocarbon groups, such as a phenyl group, a biphenylyl group, a fluorenyl group, a naphthyl group, a phenanthryl group, a terphenyl group, for example. The aryl group may or may not have a substituent. The number of nuclear carbon atoms of the aryl group is not particularly limited, but is usually in the range of 6 or more and 40 or less. The number of nuclear carbons does not include substituent carbon. This is common to the following description.

  A heteroaryl group is a furanyl group, thiophenyl group, pyridyl group, quinolinyl group, isoquinolinyl group, pyrazinyl group, pyrimidyl group, naphthyridyl group, benzofuranyl group, benzothiophenyl group, imidazolyl group, benzoimidazolyl group, indolyl group, dibenzofuranyl A cyclic aromatic group having one or more atoms other than carbon in the ring, such as a group, dibenzothiophenyl group, carbazolyl group, etc., which may be unsubstituted or substituted; The number of nuclear carbon atoms of the heteroaryl group is not particularly limited, but is usually in the range of 2 to 30.

  Halogen is fluorine, chlorine, bromine or iodine.

  The carbonyl group, carboxyl group, oxycarbonyl group, carbamoyl group, amino group, or phosphine oxide group may or may not have a substituent. Examples of the substituent include an alkyl group, a cycloalkyl group, An aryl group, a heteroaryl group, etc. are mentioned, These substituents may be further substituted.

  A silyl group refers to, for example, a functional group having a bond to a silicon atom, such as a trimethylsilyl group, which may or may not have a substituent. Although carbon number of a silyl group is not specifically limited, Usually, it is the range of 3-20. The number of silicon is usually 1 or more and 6 or less.

R ^{1 to} R ⁸ and R ^{9 to} R ¹⁶ may be bonded together with adjacent substituents to form a conjugated or non-conjugated ring. In addition to carbon, the ring may contain nitrogen, oxygen, sulfur, phosphorus, silicon atoms, or may be condensed with another ring.

As the substitution position of the substituent other than hydrogen, the position of R ¹ or R ⁵ is preferable in the general formula (1), and the position of R ⁹ or R ¹² is preferable in the general formula (2). More preferably, R ^{1 to} R ⁸ or R ^{9 to} R ¹⁶ are all hydrogen or deuterium.

  The arylene group is a divalent group derived from an aromatic hydrocarbon group such as a phenyl group, a naphthyl group, a biphenylyl group, a fluorenyl group, a phenanthryl group, or an anthracenyl group, which may have a substituent. You don't have to. The number of carbon atoms of the arylene group is not particularly limited, but is usually in the range of 6 to 40.

  A heteroarylene group is a pyridyl group, pyrazinyl group, pyrimidyl group, triazyl group, quinolinyl group, benzoquinolinyl group, quinoxalinyl group, naphthyridyl group, acridyl group, phenanthrolinyl group, thiophenyl group, benzothiophenyl group, dibenzothiophenyl group A divalent group derived from a cyclic aromatic group having one or more atoms other than carbon, such as a group, furanyl group, benzofuranyl group, dibenzofuranyl group, indolyl group, carbazolyl group, imidazolyl group, and benzoimidazolyl group. This may or may not have a substituent. The number of nuclear carbon atoms of the heteroarylene group is not particularly limited, but is usually in the range of 2 to 40.

  Heteroaryl groups having electron-accepting nitrogen are pyridyl, quinolinyl, isoquinolinyl, benzoquinolinyl, quinoxanyl, naphthyridyl, pyrazinyl, pyrimidyl, pyridazinyl, phenanthrolinyl, imidazopyridyl, triazyl At least one electron-accepting nitrogen atom as an atom other than carbon among the heteroaryl groups such as a group, an acridyl group, an imidazolyl group, a benzimidazolyl group, an oxazolyl group, a benzoxazolyl group, a thiazolyl group, and a benzothiazolyl group A plurality of cyclic aromatic groups in a ring are shown, which may be unsubstituted or substituted. The electron-accepting nitrogen mentioned here represents a nitrogen atom forming a multiple bond with an adjacent atom. Since the nitrogen atom has a high electronegativity, the multiple bond has an electron accepting property. Therefore, an aromatic heterocycle containing electron-accepting nitrogen has a high electron affinity. The number of nuclear carbon atoms of the heteroaryl group having electron-accepting nitrogen is not particularly limited, but is usually 2 or more and 40 or less.

  The compound represented by the general formula (1) or (2) is a compound in which the 1,6-position or the 1,8-position of the pyrene skeleton is substituted with a substituent containing a heteroaryl group containing an electron-accepting nitrogen. is there. In the pyrene derivative, when the 1,6-position or 1,8-position is substituted with an aromatic substituent, the electronic state of the pyrene skeleton is greatly changed, and the conjugated system is expanded. Therefore, by substituting such a position with a substituent containing a heteroaryl group containing electron-accepting nitrogen, the energy level of LUMO (minimum unoccupied orbital) localized in the pyrene skeleton is greatly stabilized. be able to. As a result, the compound represented by the general formula (1) or (2) can easily receive electrons from the cathode, and the electron mobility of the organic layer containing the compound represented by the general formula (1) or (2) is also increased. Since it improves, it is preferable. Furthermore, the energy level of the HOMO (maximum occupied orbital) of the compound represented by the general formula (1) or (2) is greatly stabilized and becomes stable against oxidation. That is, the compound represented by the general formula (1) or (2) is not easily radically cationized, and the hole blocking property is improved. Therefore, when the compound represented by the general formula (1) or (2) is used as the electron transport layer, the material can contribute to the improvement of the light emission efficiency.

  If X and Y are the same substituent, the symmetry of the molecule is too good and the crystallinity becomes high, so that a stable amorphous film cannot be formed. Since the compound represented by the general formula (1) or (2) is a substituent in which X and Y are always different, the above-mentioned concern is solved and a good amorphous thin film can be formed. Therefore, the effect of improving the durable life of the light emitting element can be obtained. Here, the fact that X and Y are different substituents will be described in detail. For example, even when both X and Y are p- (pyridyl) phenyl groups, if the pyridyl group at the end of X is a 2-pyridyl group and the pyridyl group at the end of Y is a 3-pyridyl group, then X and Y Are considered different substituents. In addition, even if both X and Y are p- (2-pyridyl) phenyl groups, X and Y are still different as long as there is a difference in the presence or absence of the substituent of each pyridyl group or phenylene group or the kind of the substituent. Are considered to be different substituents. For example, p- (2- (4-methyl) pyridyl) phenyl group and p- (2- (5-methyl) pyridyl) phenyl group are different substituents.

Although n is an integer of 1 to 5, when n is 3 to 5, HAr ¹ is sterically crowded and the substituent X has a twisted structure, which may cause a decrease in electron mobility. Therefore, n is preferably 1 or 2. Furthermore, n = 2 is more preferable in that the glass transition temperature becomes high and a stable amorphous thin film can be formed.

Examples of the case where Ar ¹ is a residue derived from an aryl group having 6 to 14 nuclear carbon atoms are not particularly limited, but specifically include a phenyl group, a naphthyl group, a biphenylyl group, a fluorenyl group, an anthracenyl group, Or the residue guide | induced from a phenanthrenyl group etc. is mention | raise | lifted. Among these, a residue derived from a phenyl group, a naphthyl group, a biphenylyl group, or a fluorenyl group is more preferable, and a residue derived from a phenyl group is more preferable from the viewpoint of synthesis cost and resistance to heat load during vapor deposition. In addition, examples of the case where Ar ¹ is a residue derived from a heteroaryl group having 2 to 14 nuclear carbon atoms are not particularly limited. Specifically, pyridyl group, pyrazinyl group, pyrimidyl group, triazyl group, quinolinyl Group, isoquinolinyl group, benzoquinolinyl group, quinoxalinyl group, naphthyridyl group, acridyl group, phenanthrolinyl group, thiophenyl group, benzothiophenyl group, dibenzothiophenyl group, furanyl group, benzofuranyl group, dibenzofuranyl group, indolyl group, Examples thereof include residues derived from a carbazolyl group, an imidazolyl group, a benzimidazolyl group, and the like. Among these, those containing electron-accepting nitrogen are preferable, and those containing no 5-membered ring are preferable from the viewpoint of chemical stability. Among these, a residue derived from a pyridyl group, a pyrazinyl group, a pyrimidyl group, a triazyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxalinyl group, a naphthyridyl group, an acridyl group, or a phenanthrolinyl group is more preferable. Furthermore, a residue derived from a pyridyl group, a pyrazinyl group, or a pyrimidyl group is particularly preferable from the viewpoints of resistance to heat load during vapor deposition and synthesis cost.

Specific examples of L ¹ include, but are not limited to, a divalent residue derived from a single bond, a phenylene group, a naphthalenylene group, a biphenylene group, a terphenylene group, a fluorenylene group, an anthracenylene group, a pyridylene group, or a pyrimidine. , Divalent residues derived from pyrazine, divalent residues derived from triazine, divalent residues derived from quinoline, divalent residues derived from isoquinoline, divalent residues derived from quinoxaline , Divalent residues derived from thiophene, divalent residues derived from furan, divalent residues derived from pyrrole, divalent residues derived from carbazole, divalent residues derived from dibenzofuran And divalent residues derived from dibenzothiophene. Among these, a single bond, a phenylene group, a biphenylene group, a naphthalenylene group, a fluorenylene group, a pyridylene group, a divalent residue derived from pyrimidine, a divalent residue derived from pyrazine, a divalent residue derived from quinoline Or a divalent residue derived from isoquinoline is more preferred. More preferred are a single bond, a phenylene group, and a pyridylene group.

HAr ¹ is a heteroaryl group containing an electron-accepting nitrogen and is not particularly limited. Specifically, a pyridyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxanyl group, a naphthyridyl group, a pyrazinyl group, a pyrimidyl group, Examples include pyridazinyl group, phenanthrolinyl group, imidazopyridyl group, triazyl group, acridyl group, imidazolyl group, benzoimidazolyl group, oxazolyl group, benzoxazolyl group, thiazolyl group, and benzothiazolyl group. Among these, those that do not contain a 5-membered ring are preferable from the viewpoint of chemical or thermal stability during vapor deposition. Pyridyl group, quinolinyl group, isoquinolinyl group, benzoquinolinyl group, quinoxanyl group, naphthyridyl group, pyrazinyl group, pyrimidyl group , A pyridazinyl group, a phenanthrolinyl group, a triazyl group, or an acridyl group is more preferable. From the viewpoint of easy synthesis and formation of a strong hydrogen bond network, a pyridyl group, a pyrimidyl group, a quinolinyl group, and an isoquinolinyl group are more preferable, and a pyridyl group is particularly preferable. Among the pyridyl groups, a 3-pyridyl group or a 4-pyridyl group is preferable, and a 4-pyridyl group is most preferable.

  As a result of intensive studies on the durability life of the light-emitting element by the present inventors, in addition to the essential deterioration such as decomposition and alteration of the material itself constituting the light-emitting element, some film quality change occurs in the electron transport layer due to an electric field during driving, It has been found that this has an adverse effect on the endurance life. Although details are not clear, it is thought that this change in film quality is caused by the movement of molecules in the electron transport layer due to the application of an electric field. It has also been found that the durability life tends to be improved when a compound that is considered to be capable of actively utilizing intermolecular interaction and suppressing molecular motion is used in the electron transport layer. From the above viewpoint, it is preferable that X is a substituent represented by the general formula (3) because the intermolecular interaction becomes strong. Further, it is more preferable that X is a substituent represented by the general formula (5), since the intermolecular interaction becomes stronger and the movement of the molecule can be suppressed.

L ¹ and HAr ¹ are as described above. R ^{19 to} R ²¹ are the same as those described above for R ^{1 to} R ¹⁶ . Two HAr ¹ may be the same or different.

In general, it is known that a nitrogen atom in a heteroaryl group having electron-accepting nitrogen forms a hydrogen bond with a hydrogen atom in an adjacent molecule. The substituent represented by the general formula (5) has a heteroaryl group containing an electron-accepting nitrogen having a hydrogen bonding property as described above, at the meta position and the meta ′ position of the benzene ring. Therefore, the compound having a substituent represented by the general formula (5) can form a strong hydrogen bonding network between adjacent molecules, and can suppress the movement of molecules due to the application of an electric field as described above. . Furthermore, since the substituent represented by the general formula (5) is steric, the glass transition temperature can also be improved, and the durable life of the light-emitting element can be greatly improved by these synergistic effects. Preferable examples of R ^{19 to} R ²¹ include hydrogen or deuterium, an alkyl group, an aryl group, and a heteroaryl group, and hydrogen or deuterium is more preferable.

  Specific examples of the substituent represented by the general formula (5) include the following, but are not limited thereto.

Specific examples of L ² include, but are not limited to, those similar to Ar ¹ in addition to a single bond. Of these, a single bond or a residue derived from a phenyl group, biphenylyl group, fluorenyl group, naphthalenyl group, pyridyl group, pyrimidyl group, quinolinyl group or isoquinolinyl group is preferable. More preferably, it is a residue derived from a single bond or a phenyl group, biphenylyl group or fluorenyl group, and a residue derived from a single bond or a phenyl group is particularly preferred. The particularly preferred reasons are described below.

The heteroaryl group HAr ² having electron-accepting nitrogen contained in Y plays a role of adjusting the energy level of LUMO mainly localized in the pyrene skeleton. The LUMO energy level is closely related to the ease with which electrons are received from the cathode and the ease with which electrons are injected into the light-emitting layer, and is one of the major factors involved in improving the light-emitting efficiency and lifetime of light-emitting elements. The ease of adjustment of the LUMO energy level is affected by the distance between the HAr ² and the pyrene skeleton and the spread of π conjugate. The closer the distance HAr ² and pyrene skeleton and the more HAr ² and pyrene skeleton is if π-conjugated, the energy level of LUMO localized in pyrene skeleton is influenced electron accepting possessed by HAr ² This makes it easier for the LUMO energy level to change. That is, when L ² is a single bond in which the distance between pyrene and HAr ² is the shortest or a residue derived from a phenyl group that is relatively short and π-conjugated, the LUMO energy level is HAR ² . Be susceptible. In light-emitting elements, the LUMO energy level of the optimal electron transport material varies depending on the cathode material and the light-emitting material used, and it becomes possible to finely adjust the LUMO energy level by changing the type of HAr ^2. Compounds with the optimal LUMO energy level can be found. Conversely, the farther the distance between the HAr ² and the pyrene skeleton is, and the more the conjugated system is cleaved, the more difficult the fine adjustment of the LUMO energy level is. Therefore, L ² is particularly preferably a single bond or a residue derived from a phenyl group.

m represents an integer of 1 to 5 when L ² is other than a single bond, but when m is 4 or 5, the molecular weight becomes too large, and there is a concern of thermal decomposition during vapor deposition. Is an integer from 1 to 3, more preferably m is 1 or 2.

A specific example of HAr ² is the same as HAr ¹ . Among these, a pyridyl group, a quinolinyl group, an isoquinolinyl group, a benzoquinolinyl group, a quinoxanyl group, a naphthyridyl group, a pyrazinyl group, a pyrimidyl group, a pyridazinyl group, a phenanthrolinyl group, a triazyl group, or an acridyl group is more preferable. From the viewpoint of easy and easy tuning of the LUMO energy level, a pyridyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, a pyrimidyl group, a triazyl group, or an acridyl group is more preferable. Among these, a pyridyl group, a quinolinyl group, an isoquinolinyl group, a pyrazinyl group, or a pyrimidyl group is more preferable from the viewpoint that a high electron mobility can be obtained and the voltage of the light emitting element can be lowered.

  A pyridyl group is particularly preferable, and among the pyridyl groups, a 3-pyridyl group or a 4-pyridyl group is more preferable.

The compound represented by the general formula (1) or (2) can be synthesized by combining known reactions such as halogenation and Suzuki coupling reaction. As an example, a synthesis scheme is shown below. The synthesis method is not limited to this. In this synthetic route, by changing the type of boronic acid used in the first step reaction, the substitution position of HAr ^{1 and} the number of substitutions n can be adjusted, and the type of boronic acid used in the third step reaction is changed. Thus, the type of HAr ² can be selected. That is, compounds having various LUMO energy levels can be easily synthesized.

  Although it does not specifically limit as a compound represented by the said General formula (1) or (2), The following examples are specifically mentioned.

  Next, embodiments of the light emitting device of the present invention will be described in detail. The light emitting device of the present invention has an anode and a cathode, and an organic layer interposed between the anode and the cathode, and the organic layer includes at least a light emitting layer and an electron transport layer, and the light emitting layer emits light by electric energy. To do.

  The organic layer is composed of only the light emitting layer / electron transport layer, 1) hole transport layer / light emitting layer / electron transport layer and 2) hole transport layer / light emitting layer / electron transport layer / electron injection layer, 3) Laminate structure such as hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer can be mentioned. Each of the layers may be a single layer or a plurality of layers.

  Although the compound represented by the general formula (1) or (2) may be used in any layer in the above device configuration, it is excellent in electron injection and transport properties, and therefore has an electron transport layer or electron injection. It is preferable to use it for the layer.

  In the light emitting device of the present invention, the anode and the cathode have a role for supplying a sufficient current for light emission of the device, and at least one of them is preferably transparent or translucent in order to extract light. Usually, the anode formed on the substrate is a transparent electrode.

  The material used for the anode is a material that can efficiently inject holes into the organic layer, and is transparent or translucent to extract light. Tin oxide, indium oxide, indium tin oxide (ITO) indium zinc oxide (IZO) Although not particularly limited, such as conductive metal oxides such as, metals such as gold, silver and chromium, inorganic conductive materials such as copper iodide and copper sulfide, conductive polymers such as polythiophene, polypyrrole and polyaniline It is particularly desirable to use ITO glass or Nesa glass. These electrode materials may be used alone, or a plurality of materials may be laminated or mixed. The resistance of the transparent electrode is not limited as long as a current sufficient for light emission of the element can be supplied, but it is desirable that the resistance be low from the viewpoint of power consumption of the element. For example, an ITO substrate with a resistance of 300Ω / □ or less will function as a device electrode, but since it is now possible to supply a substrate with a resistance of approximately 10Ω / □, use a substrate with a low resistance of 20Ω / □ or less. Is particularly desirable. The thickness of ITO can be arbitrarily selected according to the resistance value, but is usually used in a range of 100 to 300 nm.

In order to maintain the mechanical strength of the light emitting element, the light emitting element is preferably formed over a substrate. As the substrate, a glass substrate such as soda glass or non-alkali glass is preferably used. As the thickness of the glass substrate, it is sufficient that the thickness is sufficient to maintain the mechanical strength. As for the glass material, alkali-free glass is preferred because it is better that there are fewer ions eluted from the glass. Alternatively, soda lime glass provided with a barrier coat such as SiO ₂ is also commercially available and can be used. Furthermore, if the first electrode functions stably, the substrate need not be glass, and for example, an anode may be formed on a plastic substrate. The ITO film forming method is not particularly limited, such as an electron beam method, a sputtering method, and a chemical reaction method.

  The material used for the cathode is not particularly limited as long as it can efficiently inject electrons into the light emitting layer. Generally, metals such as platinum, gold, silver, copper, iron, tin, aluminum, and indium, or alloys and multilayer stacks of these metals with low work function metals such as lithium, sodium, potassium, calcium, and magnesium Is preferred. Among these, aluminum, silver, and magnesium are preferable as the main component from the viewpoints of electrical resistance, ease of film formation, film stability, luminous efficiency, and the like. In particular, magnesium and silver are preferable because electron injection into the electron transport layer and the electron injection layer in the present invention is facilitated and low voltage driving is possible.

  Furthermore, for cathode protection, metals such as platinum, gold, silver, copper, iron, tin, aluminum and indium, or alloys using these metals, inorganic materials such as silica, titania and silicon nitride, polyvinyl alcohol, polyvinyl chloride As a preferred example, an organic polymer compound such as a hydrocarbon polymer compound is laminated on the cathode as a protective film layer. Moreover, the compound represented by General formula (1) or (2) can also be utilized as this protective film layer. However, in the case of an element structure (top emission structure) that extracts light from the cathode side, the protective film layer is selected from materials that are light transmissive in the visible light region. The production method of these electrodes is not particularly limited, such as resistance heating, electron beam, sputtering, ion plating and coating.

  The hole transport layer is formed by a method of laminating or mixing one or more hole transport materials or a method using a mixture of a hole transport material and a polymer binder. In addition, the hole transport material needs to efficiently transport holes from the positive electrode between electrodes to which an electric field is applied, has high hole injection efficiency, and can efficiently transport injected holes. desirable. For this purpose, it is required that the material has an appropriate ionization potential, has a high hole mobility, is excellent in stability, and does not easily generate trapping impurities during manufacture and use. Although it does not specifically limit as a substance which satisfy | fills such conditions, For example, 4,4'-bis (N- (3-methylphenyl) -N-phenylamino) biphenyl (TPD), 4,4 ' -Bis (N- (1-naphthyl) -N-phenylamino) biphenyl (NPD), 4,4'-bis (N, N-bis (4-biphenylyl) amino) biphenyl (TBDB), bis (N, N Benzidine derivatives such as '-diphenyl-4-aminophenyl) -N, N-diphenyl-4,4'-diamino-1,1'-biphenyl (TPD232), 4,4', 4 "-tris (3-methylphenyl) (Phenyl) amino) triphenylamine (m-MTDATA), 4,4 ′, 4 ″ -tris (1-naphthyl (phenyl) amino) triphenylamine (1-TNATA) A group of materials called starburst arylamine, carbazole dimer derivatives such as bis (N-allylcarbazole) or bis (N-alkylcarbazole), carbazole trimer derivatives, carbazole tetramer derivatives, triphenylene compounds , Pyrazoline derivatives, stilbene compounds, hydrazone compounds, benzofuran derivatives and thiophene derivatives, oxadiazole derivatives, phthalocyanine derivatives, porphyrin derivatives and other heterocyclic compounds, fullerene derivatives, polycarbonates having the above monomers in the side chain And styrene derivatives, polythiophene, polyaniline, polyfluorene, polyvinylcarbazole and polysilane are preferred. Furthermore, inorganic compounds such as p-type Si and p-type SiC can also be used.

  Since the compound represented by the general formula (1) or (2) has excellent electron injecting and transporting properties, when this is used in the electron transporting layer, electrons are not recombined in the light emitting layer, and some holes are transported. There is a concern that even the layer will leak. Therefore, it is preferable to use a compound having an excellent electron blocking property for the hole transport layer. Among these, a compound containing a carbazole skeleton is preferable because it has excellent electron blocking properties and can contribute to high light emission efficiency of the light emitting element. Further, it is more preferable that the compound containing the carbazole skeleton contains a good carbazole dimer, carbazole trimer, or carbazole tetramer skeleton because it has both good electron blocking properties and hole injection / transport properties. Furthermore, when a compound containing a carbazole skeleton is used for the hole transport layer, the compound having the carbazole skeleton also has a high triplet exciton blocking function if the combined light-emitting layer contains a phosphorescent material described later. Therefore, it is more preferable because high luminous efficiency can be achieved. In addition, it is preferable to use a compound containing a triphenylene skeleton, which is excellent in having high hole mobility, in the hole transport layer because the effects of improving the carrier balance and improving the light emission efficiency and durability are obtained. More preferably, the compound containing a triphenylene skeleton has two or more diarylamino groups. The compound containing a carbazole skeleton or the compound containing a triphenylene skeleton may be used alone as a hole transport layer, or may be used as a mixture with each other. Further, other materials may be mixed within a range not impairing the effects of the present invention. In the case where the hole transport layer is composed of a plurality of layers, any one layer may contain a compound containing a carbazole skeleton or a compound containing a triphenylene skeleton.

  A hole injection layer may be provided between the anode and the hole transport layer. Providing the hole injection layer lowers the voltage of the light emitting element and improves the durability life. For the hole injection layer, a material having a smaller ionization potential than that of the material normally used for the hole transport layer is preferably used. Specifically, a benzidine derivative such as TPD232 and a starburst arylamine material group can be used, and a phthalocyanine derivative can also be used. It is also preferred that the hole injection layer is composed of an acceptor compound alone, or that the acceptor compound is doped into another hole transport material. Examples of acceptor compounds include metal chlorides such as iron (III) chloride, aluminum chloride, gallium chloride, indium chloride, antimony chloride, metal oxides such as molybdenum oxide, vanadium oxide, tungsten oxide, ruthenium oxide, A charge transfer complex such as tris (4-bromophenyl) aminium hexachloroantimonate (TBPAH). In addition, organic compounds having a nitro group, cyano group, halogen or trifluoromethyl group in the molecule, quinone compounds, acid anhydride compounds, fullerenes, and the like are also preferably used. Specific examples of these compounds include hexacyanobutadiene, hexacyanobenzene, tetracyanoethylene, tetracyanoquinodimethane (TCNQ), tetrafluorotetracyanoquinodimethane (F4-TCNQ), 2, 3, 6, 7 , 10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN6), p-fluoranyl, p-chloranil, p-bromanyl, p-benzoquinone, 2,6-dichlorobenzoquinone 2,5-dichlorobenzoquinone, tetramethylbenzoquinone, 1,2,4,5-tetracyanobenzene, o-dicyanobenzene, p-dicyanobenzene, 1,4-dicyanotetrafluorobenzene, 2,3-dichloro-5 , 6-Dicyanobenzoquinone, p-dinitrobenzene, m-dini Lobenzene, o-dinitrobenzene, p-cyanonitrobenzene, m-cyanonitrobenzene, o-cyanonitrobenzene, 1,4-naphthoquinone, 2,3-dichloronaphthoquinone, 1-nitronaphthalene, 2-nitronaphthalene, 1,3-dinitro Naphthalene, 1,5-dinitronaphthalene, 9-cyanoanthracene, 9-nitroanthracene, 9,10-anthraquinone, 1,3,6,8-tetranitrocarbazole, 2,4,7-trinitro-9-fluorenone, 2 , 3,5,6-tetracyanopyridine, maleic anhydride, phthalic anhydride, C60, and C70.

  Among these, metal oxides and cyano group-containing compounds are preferable because they are easy to handle and easy to deposit, so that the above-described effects can be easily obtained. Examples of preferred metal oxides include molybdenum oxide, vanadium oxide, or ruthenium oxide. Among the cyano group-containing compounds, (a) a compound having at least one electron-accepting nitrogen other than the nitrogen atom of the cyano group in the molecule and further having a cyano group, (b) a halogen and a cyano group in the molecule (C) a compound having both a carbonyl group and a cyano group in the molecule, or (d) an electron-accepting nitrogen other than the nitrogen atom of the cyano group, a halogen and a cyano group. A compound having all is more preferable because it becomes a strong electron acceptor. Specific examples of such a compound include the following compounds.

  In any case where the hole injection layer is composed of an acceptor compound alone or when the hole injection layer is doped with an acceptor compound, the hole injection layer may be a single layer, A plurality of layers may be laminated. Moreover, the hole injection material used in combination when the acceptor compound is doped is the same compound as the compound used for the hole transport layer from the viewpoint that the hole injection barrier to the hole transport layer can be relaxed. Is more preferable.

  In the present invention, the light emitting layer may be either a single layer or a plurality of layers, each formed of a light emitting material (host material, dopant material), which may be a mixture of a host material and a dopant material or a host material alone. It may be either. That is, in the light emitting element of the present invention, only the host material or the dopant material may emit light in each light emitting layer, or both the host material and the dopant material may emit light. From the viewpoint of efficiently using electric energy and obtaining light emission with high color purity, the light emitting layer is preferably composed of a mixture of a host material and a dopant material. Further, the host material and the dopant material may be either one kind or a plurality of combinations, respectively. The dopant material may be included in the entire host material or may be partially included. The dopant material may be laminated or dispersed. The dopant material can control the emission color. If the amount of the dopant material is too large, a concentration quenching phenomenon occurs, so that it is preferably used at 20% by weight or less, more preferably 10% by weight or less with respect to the host material. The doping method can be formed by a co-evaporation method with a host material, but may be simultaneously deposited after being previously mixed with the host material.

  The light emitting layer may be either a single layer or a plurality of layers, each formed by a light emitting material (host material, dopant material), which may be a mixture of a host material and a dopant material or a host material alone, Either is acceptable. That is, in the light emitting element of the present invention, only the host material or the dopant material may emit light in each light emitting layer, or both the host material and the dopant material may emit light. From the viewpoint of efficiently using electric energy and obtaining light emission with high color purity, the light emitting layer is preferably composed of a mixture of a host material and a dopant material. Further, the host material and the dopant material may be either one kind or a plurality of combinations, respectively. The dopant material may be included in the entire host material or may be partially included. The dopant material may be laminated or dispersed. The dopant material can control the emission color. If the amount of the dopant material is too large, a concentration quenching phenomenon occurs, so that it is preferably used at 20% by weight or less, more preferably 10% by weight or less with respect to the host material. The doping method can be formed by a co-evaporation method with a host material, but may be simultaneously deposited after being previously mixed with the host material.

  Specifically, the light-emitting material includes condensed ring derivatives such as anthracene and pyrene, which have been known as light emitters, metal chelated oxinoid compounds such as tris (8-quinolinolato) aluminum, bisstyrylanthracene derivatives and diesters. Bisstyryl derivatives such as styrylbenzene derivatives, tetraphenylbutadiene derivatives, indene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, dibenzofuran derivatives, carbazole In derivatives, indolocarbazole derivatives, and polymer systems, polyphenylene vinylene derivatives, polyparaphenylene derivatives, polythiophene derivatives, etc. can be used, but are not particularly limited. Not.

  The host material contained in the light emitting material is not particularly limited, but is a compound having a condensed aryl ring such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, naphthacene, triphenylene, perylene, fluoranthene, fluorene, indene, and derivatives thereof, N, Aromatic amine derivatives such as N′-dinaphthyl-N, N′-diphenyl-4,4′-diphenyl-1,1′-diamine, metal chelating oxinoids including tris (8-quinolinato) aluminum (III) Compounds, bisstyryl derivatives such as distyrylbenzene derivatives, tetraphenylbutadiene derivatives, indene derivatives, coumarin derivatives, oxadiazole derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, pyrrolopyrrole derivatives, thia In the case of an azolopyridine derivative, a dibenzofuran derivative, a carbazole derivative, an indolocarbazole derivative, a triazine derivative, or a polymer system, a polyphenylene vinylene derivative, a polyparaphenylene derivative, a polyfluorene derivative, a polyvinyl carbazole derivative, a polythiophene derivative, or the like can be used, but is particularly limited. It is not a thing. The dopant material is not particularly limited, but is a compound having a condensed aryl ring such as naphthalene, anthracene, phenanthrene, pyrene, chrysene, triphenylene, perylene, fluoranthene, fluorene, indene or a derivative thereof (for example, 2- (benzothiazole-2) -Yl) -9,10-diphenylanthracene, 5,6,11,12-tetraphenylnaphthacene), furan, pyrrole, thiophene, silole, 9-silafluorene, 9,9'-spirobisilafluorene, benzo Compounds having heteroaryl rings such as thiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenanthroline, pyridine, pyrazine, naphthyridine, quinoxaline, pyrrolopyridine, thioxanthene Derivatives thereof, borane derivatives, distyrylbenzene derivatives, 4,4′-bis (2- (4-diphenylaminophenyl) ethenyl) biphenyl, 4,4′-bis (N- (stilben-4-yl) -N— Aminostyryl derivatives such as phenylamino) stilbene, aromatic acetylene derivatives, tetraphenylbutadiene derivatives, stilbene derivatives, aldazine derivatives, pyromethene derivatives, diketopyrrolo [3,4-c] pyrrole derivatives, 2,3,5,6-1H, Coumarin derivatives such as 4H-tetrahydro-9- (2′-benzothiazolyl) quinolidino [9,9a, 1-gh] coumarin, azole derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole and triazole and their metals Complex and N, '- diphenyl -N, etc. N'- di (3-methylphenyl) -4,4'-aromatic amine derivative typified by diphenyl-1,1'-diamine can be used.

  The light emitting layer may contain a phosphorescent material. A phosphorescent material is a material that exhibits phosphorescence even at room temperature. As a dopant, it is basically necessary to obtain phosphorescence even at room temperature, but it is not particularly limited, and iridium (Ir), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum ( An organometallic complex compound containing at least one metal selected from the group consisting of Pt), osmium (Os), and rhenium (Re) is preferable. Among these, from the viewpoint of having a high phosphorescence emission yield even at room temperature, an organometallic complex having iridium or platinum is more preferable. Hosts of phosphorescent materials include indole derivatives, carbazole derivatives, indolocarbazole derivatives, pyridine, pyrimidine, nitrogen-containing aromatic compound derivatives having a triazine skeleton, polyarylbenzene derivatives, spirofluorene derivatives, truxene derivatives, triphenylene derivatives, etc. A compound containing a chalcogen element such as an aromatic hydrocarbon compound derivative, a dibenzofuran derivative or a dibenzothiophene derivative, or an organometallic complex such as a beryllium quinolinol complex is preferably used. As long as holes are smoothly injected and transported from the respective transport layers, the present invention is not limited thereto. Two or more triplet light-emitting dopants may be contained, or two or more host materials may be contained. Further, one or more triplet light emitting dopants and one or more fluorescent light emitting dopants may be contained.

  The preferred phosphorescent host or dopant is not particularly limited, but specific examples include the following.

  In the present invention, the electron transport layer is a layer in which electrons are injected from the cathode and further transports electrons. The electron transport layer has high electron injection efficiency, and it is desired to efficiently transport injected electrons. Therefore, it is desirable that the electron transport layer is made of a material having a high electron affinity, a high electron mobility, excellent stability, and a trapping impurity that is unlikely to be generated during manufacture and use. However, considering the transport balance between holes and electrons, if the electron transport layer mainly plays a role of effectively preventing the holes from the anode from recombining and flowing to the cathode side, the electron transport Even if it is made of a material that does not have a high capability, the effect of improving the luminous efficiency is equivalent to that of a material that has a high electron transport capability. Therefore, the electron transport layer in the present invention includes a hole blocking layer that can efficiently block the movement of holes as the same meaning.

  The compound represented by the general formula (1) or (2) is a compound that satisfies the above conditions, and has high electron injecting and transporting ability, so that it is suitably used as an electron transporting material.

  Since the compound represented by the general formula (1) or (2) contains a heteroaryl group having an electron-accepting nitrogen at the 1,6-position or 1,8-position of the pyrene skeleton, the electron injecting and transporting property, electrochemical Excellent stability. In addition, the introduction of the substituent improves compatibility in a thin film state with a donor compound described later, and exhibits higher electron injecting and transporting ability. By the action of the mixture layer, the transport of electrons from the cathode to the light emitting layer is promoted, and both high luminous efficiency and low driving voltage can be achieved.

  The electron transport material used in the present invention need not be limited to only one kind of each compound represented by the general formula (1) or (2) of the present invention, and a plurality of pyrene compounds of the present invention may be used in combination. One or more other electron transport materials may be mixed with the pyrene compound of the present invention as long as the effects of the present invention are not impaired. The electron transport material that can be mixed is not particularly limited, but is a compound having a condensed aryl ring such as naphthalene, anthracene, or pyrene or a derivative thereof, or a styryl-based fragrance typified by 4,4′-bis (diphenylethenyl) biphenyl. Ring derivatives, perylene derivatives, perinone derivatives, coumarin derivatives, naphthalimide derivatives, quinone derivatives such as anthraquinone and diphenoquinone, phosphorus oxide derivatives, carbazole derivatives and indole derivatives, quinolinol complexes such as tris (8-quinolinolato) aluminum (III) and hydroxy Examples include hydroxyazole complexes such as phenyloxazole complexes, azomethine complexes, tropolone metal complexes, and flavonol metal complexes.

  Next, the donor compound will be described. The donor compound in the present invention is a compound that facilitates electron injection from the cathode or the electron injection layer to the electron transport layer by improving the electron injection barrier, and further improves the electrical conductivity of the electron transport layer. That is, the light-emitting device of the present invention is more preferably a compound obtained by doping an electron transport layer with a donor compound in order to improve the electron transport capability in addition to the compound represented by the general formula (1) or (2). preferable.

  Preferred examples of the donor compound in the present invention include an alkali metal, an inorganic salt containing an alkali metal, a complex of an alkali metal and an organic substance, an alkaline earth metal, an inorganic salt containing an alkaline earth metal, or an alkaline earth metal. And a complex of organic substance. Preferable types of alkali metals and alkaline earth metals include alkali metals such as lithium, sodium and cesium, which have a low work function and a large effect of improving the electron transport ability, and alkaline earth metals such as magnesium and calcium.

In addition, since it is easy to deposit in vacuum and is excellent in handling, it is preferably in the form of a complex with an inorganic salt or an organic substance rather than a single metal. Furthermore, it is more preferable that it is in the state of a complex with an organic substance in terms of facilitating handling in the air and easy control of the addition concentration. Examples of inorganic salts include oxides such as LiO and Li ₂ O, nitrides, fluorides such as LiF, NaF, and KF, Li ₂ CO ₃ , Na ₂ CO ₃ , K ₂ CO ₃ , Rb ₂ CO ₃ , Examples thereof include carbonates such as Cs ₂ CO ₃ . A preferable example of the alkali metal or alkaline earth metal is lithium from the viewpoint that the raw materials are inexpensive and easy to synthesize. Preferred examples of the organic substance in the complex with the organic substance include quinolinol, benzoquinolinol, flavonol, hydroxyimidazopyridine, hydroxybenzazole, hydroxytriazole and the like. Among these, a complex of an alkali metal and an organic substance is preferable, a complex of lithium and an organic substance is more preferable, and lithium quinolinol is particularly preferable. Two or more of these donor compounds may be mixed and used.

  The preferred doping concentration varies depending on the material and the thickness of the doped region. For example, when the donor compound is an inorganic material such as an alkali metal or alkaline earth metal, the deposition rate ratio of the electron transport material and the donor compound is 10,000: It is preferable to use an electron transport layer by co-evaporation so as to be in the range of 1 to 2: 1. The deposition rate ratio is more preferably 100: 1 to 5: 1, and further preferably 100: 1 to 10: 1. When the donor compound is a complex of a metal and an organic substance, the electron transport layer and the donor compound are co-deposited so that the deposition rate ratio of the donor compound is in the range of 100: 1 to 1: 100. Is preferred. The deposition rate ratio is more preferably 10: 1 to 1:10, and more preferably 7: 3 to 3: 7.

  The electron transport layer in which the compound represented by the general formula (1) or (2) is doped with a donor compound is used as a charge generation layer in a tandem structure type element that connects a plurality of light emitting elements. It may be done.

  The method of doping the electron transport layer with a donor compound to improve the electron transport capability is particularly effective when the thin film layer is thick. It is particularly preferably used when the total film thickness of the electron transport layer and the light emitting layer is 50 nm or more. For example, there is a method of using the interference effect to improve the light emission efficiency, but this improves the light extraction efficiency by matching the phase of the light directly emitted from the light emitting layer and the light reflected by the cathode. Is. This optimum condition varies depending on the light emission wavelength, but the total film thickness of the electron transport layer and the light-emitting layer is 50 nm or more, and in the case of long-wavelength light emission such as red, it may be a thick film near 100 nm. .

  The electron transport layer to be doped may have either a part or all of the electron transport layer. In the case of partial doping, it is desirable to provide a doping region at least at the electron transport layer / cathode interface, and the effect of lowering the voltage can be obtained only by doping in the vicinity of the cathode interface. On the other hand, if the donor compound is in direct contact with the light emitting layer, it may adversely affect the light emission efficiency. In that case, it is desirable to provide a non-doped region at the light emitting layer / electron transport layer interface.

In the present invention, an electron injection layer may be provided between the cathode and the electron transport layer. In general, the electron injection layer is inserted for the purpose of assisting injection of electrons from the cathode to the electron transport layer, but in the case of insertion, a compound having a heteroaryl ring structure containing electron-accepting nitrogen may be used. A layer containing the above donor compound may be used. The compound represented by the general formula (1) or (2) may be included in the electron injection layer. An insulator or a semiconductor inorganic substance can also be used for the electron injection layer. Use of these materials is preferable because a short circuit of the light emitting element can be effectively prevented and the electron injection property can be improved. As such an insulator, it is preferable to use at least one metal compound selected from the group consisting of alkali metal chalcogenides, alkaline earth metal chalcogenides, alkali metal halides and alkaline earth metal halides. If the electron injection layer is composed of these alkali metal chalcogenides or the like, it is more preferable because the electron injection property can be further improved. Specifically, preferred alkali metal chalcogenides include, for example, Li ₂ O, Na ₂ S, and Na ₂ Se, and preferred alkaline earth metal chalcogenides include, for example, CaO, BaO, SrO, BeO, BaS, and CaSe. Is mentioned. Further, preferable alkali metal halides include, for example, LiF, NaF, KF, LiCl, KCl, and NaCl. Examples of preferable alkaline earth metal halides include fluorides such as CaF ₂ , BaF ₂ , SrF ₂ , MgF ₂ and BeF ₂ , and halides other than fluorides. Furthermore, a complex of an organic substance and a metal is also preferably used. When an insulator or a semiconductor inorganic material is used for the electron injection layer, if the film thickness is too large, there may be a problem that the light emitting element is insulated or the driving voltage becomes high. That is, there is a possibility that the yield of the light-emitting element is reduced due to the film thickness margin of the electron injection layer, but it is more preferable to use a complex of an organic substance and a metal for the electron injection layer because the film thickness can be easily adjusted. Examples of such organometallic complexes include quinolinol, benzoquinolinol, pyridylphenol, flavonol, hydroxyimidazopyridine, hydroxybenzazole, hydroxytriazole, and the like as preferred examples of the organic substance in a complex with an organic substance. Among these, a complex of an alkali metal and an organic substance is preferable, a complex of lithium and an organic substance is more preferable, and lithium quinolinol is particularly preferable.

  The method of forming each layer constituting the light emitting element is not particularly limited, such as resistance heating vapor deposition, electron beam vapor deposition, sputtering, molecular lamination method, coating method, etc., but resistance heating vapor deposition or electron beam vapor deposition is usually used in terms of element characteristics. preferable.

  The thickness of the organic layer is not limited because it depends on the resistance value of the luminescent material, but is preferably 1 to 1000 nm. The film thicknesses of the light emitting layer, the electron transport layer, and the hole transport layer are each preferably 1 nm to 200 nm, and more preferably 5 nm to 100 nm.

  The light-emitting element of the present invention has a function of converting electrical energy into light. Here, a direct current is mainly used as the electric energy, but a pulse current or an alternating current can also be used. The current value and voltage value are not particularly limited, but should be selected so that the maximum luminance can be obtained with as low energy as possible in consideration of the power consumption and lifetime of the device.

  The light emitting device of the present invention is suitably used as a display for displaying in a matrix and / or segment system, for example.

  In the matrix method, pixels for display are two-dimensionally arranged such as a lattice shape or a mosaic shape, and a character or an image is displayed by a set of pixels. The shape and size of the pixel are determined by the application. For example, a square pixel with a side of 300 μm or less is usually used for displaying images and characters on a personal computer, monitor, TV, and a pixel with a side of mm order for a large display such as a display panel. become. In monochrome display, pixels of the same color may be arranged. However, in color display, red, green, and blue pixels are displayed side by side. In this case, there are typically a delta type and a stripe type. The matrix driving method may be either a line sequential driving method or an active matrix. Although the structure of the line sequential drive is simple, the active matrix may be superior in consideration of the operation characteristics, and it is necessary to use it depending on the application.

The segment system in the present invention is a system in which a pattern is formed so as to display predetermined information and an area determined by the arrangement of the pattern is caused to emit light. For example, the time and temperature display in a digital clock or a thermometer, the operation state display of an audio device or an electromagnetic cooker, the panel display of an automobile, and the like can be mentioned. The matrix display and the segment display may coexist in the same panel.
The light emitting device of the present invention is also preferably used as a backlight for various devices. The backlight is used mainly for the purpose of improving the visibility of a display device that does not emit light, and is used for a liquid crystal display device, a clock, an audio device, an automobile panel, a display panel, a sign, and the like. In particular, the light-emitting element of the present invention is preferably used for a backlight for a liquid crystal display device, particularly a personal computer for which a reduction in thickness is being considered, and a backlight that is thinner and lighter than conventional ones can be provided.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited by these Examples.

Synthesis Example 1 (Synthesis of Compounds D (E-5) and E (E-12))
Synthesis of Compound A 18.4 g of 1-bromopyrene, 15 g of 3,5-dichlorophenylboronic acid, and 0.92 g of PdCl ₂ (PPh ₃ ) ₂ were charged into a 1 L four-necked flask purged with nitrogen. Further, 400 ml of DME and 200 ml of 1M Na ₂ CO ₃ aqueous solution were added, heated to 77 ° C. and stirred for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 200 ml of water was added, and the precipitated solid was collected by filtration. Further, this solid was dispersed and washed with 300 ml of water for 30 minutes and collected by filtration. This solid was dried and then purified by a silica gel column to obtain 18.9 g of Compound A. The reaction formula is shown below.

Synthesis of Compound B 18.9 g of Compound A, 9.7 g of NBS, and 400 ml of DMF were put into a 1 L four-necked flask purged with nitrogen, heated to 55 ° C., and reacted for 4 hours. After cooling to room temperature, 400 ml of water was added, and the precipitated solid was collected by filtration. This solid was further filtered and washed with 500 ml of water for 30 minutes, and then filtered and washed with 300 ml of methanol for 30 minutes. This was dried to obtain 23.0 g of Compound B (a mixture of 1,6 and 1,8-isomers). The reaction formula is shown below.

Synthesis of Compound C 11.5 g of Compound B, 4.0 g of 3-pyridineboronic acid, 0.38 g of PdCl ₂ (PPh ₃ ) ₂ , 200 ml of DME, and 100 ml of 1M Na ₂ CO ₃ aqueous solution were put into a 500 ml four-necked flask purged with nitrogen. The mixture was heated to 77 ° C. and reacted for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 100 ml of water was added, and the precipitated solid was collected by filtration. Further, this solid was dispersed and washed with 300 ml of water for 30 minutes and then collected by filtration, and then dispersed and washed with 300 ml of methanol for 30 minutes and then collected by filtration. After drying this, isomer separation was performed with a silica gel column to obtain 3.1 g of Compound 16C. The reaction formula is shown below.

Synthesis of Compound D (E-5) 3.1 g of Compound 16C, 2.7 g of 4-pyridineboronic acid, 0.17 g of Pd (dba) ₂ , 0.13 g of tricyclohexylphosphine tetrafluoroborate, 6.2 g of potassium phosphate , 100 ml of dioxane and 15 ml of water were put into a 300 ml three-necked flask purged with nitrogen and stirred at 85 ° C. for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 100 ml of water was added, and the precipitated solid was collected by filtration. Further, this solid was dispersed and washed with 300 ml of water for 30 minutes and then collected by filtration, and then dispersed and washed with 300 ml of methanol for 30 minutes and then collected by filtration and dried to obtain 3.4 g of a crude solid. This solid was recrystallized twice more to obtain 2.5 g of solid. Further, this solid was purified by sublimation to obtain 2.0 g of Compound D. The results of ¹ H-NMR analysis of the obtained solid are as follows.
¹ H-NMR (CDCl ₃ ) δ 7.51-7.56 (1H, m), 7.67 (4H, dd), 7.97-8.02 (5H, m), 8.08-8.14 (4H, m), 8.23-8.31 (3H, m ), 8.73-8.78 (5H, m), 8.91-8.92 (1H, m).
The reaction formula is shown below.

Synthesis of Compound E (E-12) 3.1 g of Compound 16C, 2.7 g of 3-pyridineboronic acid, 0.17 g of Pd (dba) ₂ , 0.13 g of tricyclohexylphosphine tetrafluoroborate, 6.2 g of potassium phosphate , 100 ml of dioxane and 15 ml of water were put into a 300 ml three-necked flask purged with nitrogen and stirred at 85 ° C. for 3 hours. After completion of the reaction, the reaction mixture was cooled to room temperature, 100 ml of water was added, and the precipitated solid was collected by filtration. Further, this solid was dispersed and washed with 300 ml of water for 30 minutes and then collected by filtration, and then dispersed and washed with 300 ml of methanol for 30 minutes, and then collected by filtration and dried to obtain 3.3 g of a crude solid. This solid was recrystallized twice more to obtain 2.4 g of solid. Further, this solid was purified by sublimation to obtain 1.9 g of compound E. The results of ¹ H-NMR analysis of the obtained solid are as follows.
¹ H-NMR (CDCl ₃ ) δ 7.42-7.46 (2H, m), 7.51-7.55 (1H, m), 7.91 (3H, s), 7.98-8.13 (8H, m), 8.26-8.32 (3H, m ), 8.67 (2H, d), 8.76 (1H, d), 8.92 (1H, s), 9.03 (2H, s).
The reaction formula is shown below.

Reference example 1
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 as a hole injection layer was deposited with a thickness of 5 nm and HT-1 as a hole transport layer was deposited with a thickness of 60 nm by a resistance heating method. Next, the host material compound H-1 and the dopant material compound D-1 were vapor-deposited to a thickness of 40 nm as the light emitting layer so that the doping concentration was 5% by weight. Next, Compound E-1 was deposited as an electron transport layer to a thickness of 25 nm and laminated. Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light emitting element at 1000 cd / m ² were a driving voltage of 4.2 V and an external quantum efficiency of 4.9%. Further, when the initial luminance was set to 1000 cd / m ² and driven at a constant current, the time for the luminance to decrease by 20% was 330 hours. HAT-CN6, HT-1, H-1, D-1, and E-1 are compounds shown below.

Examples or Reference Examples 2 to 23
A light emitting device was prepared and evaluated in the same manner as in Reference Example 1 except that the compounds described in Table 1 were used for the electron transport layer and the hole transport layer. The results are shown in Table 1. E-2 to E-15, HT-2, and 3 are the compounds shown below.

Comparative Examples 1-18
A light emitting device was prepared and evaluated in the same manner as in Reference Example 1 except that the compounds described in Table 2 were used for the electron transport layer and the hole transport layer. The results are shown in Table 2. E-16 to E-21 are the compounds shown below.

Reference Example 24
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 as a hole injection layer was deposited with a thickness of 5 nm and HT-1 as a hole transport layer was deposited with a thickness of 60 nm by a resistance heating method. Next, as a light emitting layer, the compound H-1 was used as the host material and the compound D-1 was used as the dopant material, and vapor deposition was performed to a thickness of 40 nm with a doping concentration of 5% by weight. Next, Compound E-1 was deposited to a thickness of 10 nm as a first electron transport layer and laminated. Furthermore, E-1 was used for the electron transport material as the second electron transport layer, cesium was used as the donor compound, and the layer was laminated to a thickness of 15 nm so that the deposition rate ratio of E-1 and cesium was 20: 1. Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light emitting element at 1000 cd / m ² were a driving voltage of 3.9 V and an external quantum efficiency of 5.2%. When the initial luminance was set to 1000 cd / m ² and driven at a constant current, the time for a 20% decrease in luminance was 420 hours.

Examples or Reference Examples 25-29
The first electron-transport layer, except for using the compounds described in Table 3 to the second electron transport layer to form a light-emitting element in the same manner as in Reference Example 2 4, was evaluated. The results are shown in Table 3.

Reference Example 30
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 as a hole injection layer was deposited with a thickness of 5 nm and HT-1 as a hole transport layer was deposited with a thickness of 60 nm by a resistance heating method. Next, as a light emitting layer, the compound H-1 was used as the host material and the compound D-1 was used as the dopant material, and vapor deposition was performed to a thickness of 40 nm with a doping concentration of 5% by weight. Next, Compound E-1 was deposited to a thickness of 10 nm as a first electron transport layer and laminated. Further, E-1 was used as the electron transport material for the second electron transport layer, lithium was used as the donor compound, and the layer was laminated to a thickness of 15 nm so that the deposition rate ratio between E-1 and lithium was 100: 1. Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light emitting element at 1000 cd / m ² were a driving voltage of 3.9 V and an external quantum efficiency of 5.1%. When the initial luminance was set to 1000 cd / m ² and driven at a constant current, the time for a 20% decrease in luminance was 420 hours.

Examples or Reference Examples 31 to 35
A light emitting device was prepared and evaluated in the same manner as in Reference Example 30 except that the compounds described in Table 3 were used for the first electron transport layer and the second electron transport layer. The results are shown in Table 3.

Example 36
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 as a hole injection layer was deposited with a thickness of 5 nm and HT-1 as a hole transport layer was deposited with a thickness of 60 nm by a resistance heating method. Next, as a light emitting layer, Compound H-1 was used as the host material and Compound D-1 was used as the dopant material, and vapor deposition was performed to a thickness of 40 nm so that the doping concentration was 5% by weight. Further, E-1 was used as an electron transport material as an electron transport layer, Liq was used as a donor compound, and a layer having a thickness of 25 nm was laminated so that the deposition rate ratio of E-1 and Liq was 1: 1. This electron transport layer is shown as a second electron transport layer in Table 2. Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light-emitting element at 1000 cd / m ² were a driving voltage of 4.0 V and an external quantum efficiency of 5.3%. Further, when the initial luminance was set to 1000 cd / m ² and driving at constant current was performed, the time for the luminance to decrease by 20% was 440 hours. Liq is a compound shown below.

Examples 37-41
A light emitting device was prepared and evaluated in the same manner as in Example 36 except that the compounds listed in Table 3 were used for the electron transport layer. The results are shown in Table 3.

Comparative Examples 19-23
A light emitting device was prepared and evaluated in the same manner as in Reference Example 24 except that the compounds described in Table 4 were used for the first electron transport layer and the second electron transport layer. The results are shown in Table 4.

Comparative Examples 24-28
A light emitting device was prepared and evaluated in the same manner as in Reference Example 30 except that the compounds described in Table 4 were used for the first electron transport layer and the second electron transport layer. The results are shown in Table 4.

Comparative Examples 29-33
A light emitting device was prepared and evaluated in the same manner as in Example 36 except that the compounds listed in Table 4 were used for the electron transport layer. The results are shown in Table 4.

Reference Example 42
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 as a hole injection layer was deposited with a thickness of 5 nm and HT-1 as a hole transport layer was deposited with a thickness of 60 nm by a resistance heating method. This hole transport layer is shown in Table 3 as the first hole transport layer. Next, as the light emitting layer, the host material compound H-2 and the dopant material compound D-2 were deposited to a thickness of 40 nm so that the dope concentration was 10 wt%. Next, Compound E-1 was deposited as an electron transport layer to a thickness of 25 nm and laminated.

Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light emitting device at 4000 cd / m ² were a driving voltage of 4.2 V and an external quantum efficiency of 12.0%. Further, when the initial luminance was set to 4000 cd / m ² and driven at a constant current, the time required for the luminance to decrease by 20% was 300 hours. H-2 and D-2 are the compounds shown below.

Reference Example 43
A glass substrate (manufactured by Geomat Co., Ltd., 11Ω / □, sputtered product) on which ITO transparent conductive film was deposited at 165 nm was cut into 38 × 46 mm and etched. The obtained substrate was ultrasonically cleaned with “Semico Clean 56” (trade name, manufactured by Furuuchi Chemical Co., Ltd.) for 15 minutes and then with ultrapure water. This substrate was subjected to UV-ozone treatment for 1 hour immediately before producing the device, placed in a vacuum deposition apparatus, and evacuated until the degree of vacuum in the apparatus became 5 × 10 ⁻⁴ Pa or less. First, HAT-CN6 was deposited as a hole injection layer with a thickness of 5 nm and HT-1 as a first hole transport layer was deposited with a thickness of 50 nm by a resistance heating method. Furthermore, 10 nm of HT-4 was deposited as a second hole transport layer. Next, as the light emitting layer, the host material compound H-2 and the dopant material compound D-2 were deposited to a thickness of 40 nm so that the dope concentration was 10 wt%. Next, Compound E-1 was deposited as an electron transport layer to a thickness of 25 nm and laminated.

Next, after depositing 0.5 nm of lithium fluoride, 1000 nm of aluminum was vapor-deposited to form a cathode, and a 5 × 5 mm square device was fabricated. The film thickness referred to here is a crystal oscillation type film thickness monitor display value. The characteristics of this light emitting element at 4000 cd / m ² were a driving voltage of 4.3 V and an external quantum efficiency of 13.9%. Further, when the initial luminance was set to 4000 cd / m ² and driven at a constant current, the time required for the luminance to decrease by 20% was 350 hours. HT-4 is a compound shown below.

Reference examples 44 and 45
A light emitting device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds described in Table 5 were used as the second hole transport layer. The results are shown in Table 5. HT-5 and HT-6 are the compounds shown below.

Example 46
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-5 was used as the electron transport layer. The results are shown in Table 3.

Examples 47-49
A device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds shown in Table 5 were used as the second hole transport layer and E-5 was used as the electron transport layer. The results are shown in Table 5.

Example 50
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-12 was used as the electron transport layer. The results are shown in Table 3.

Examples 51-53
A device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds shown in Table 5 were used as the second hole transport layer and E-12 was used as the electron transport layer. The results are shown in Table 5.

Comparative Example 34
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-16 was used for the electron transport layer. The results are shown in Table 6.

Comparative Examples 35-37
A device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds shown in Table 6 were used as the second hole transport layer and E-16 was used as the electron transport layer. The results are shown in Table 6.

Comparative Example 38
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-17 was used for the electron transport layer. The results are shown in Table 6. Comparative Examples 39 to 41
A device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds shown in Table 6 were used as the second hole transport layer and E-17 was used as the electron transport layer. The results are shown in Table 6.

Comparative Example 42
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-18 was used for the electron transport layer. The results are shown in Table 6.

Comparative Examples 43-45
A device was prepared and evaluated in the same manner as in Reference Example 43 except that the compounds shown in Table 6 were used as the second hole transport layer and E-18 was used as the electron transport layer. The results are shown in Table 6.

Comparative Example 46
A light emitting device was prepared and evaluated in the same manner as in Reference Example 42 except that E-19 was used for the electron transport layer. The results are shown in Table 6.

Comparative Examples 47-49
A device was prepared and evaluated in the same manner as in Reference Example 43, except that the compounds shown in Table 6 were used as the second hole transport layer and E-19 was used as the electron transport layer. The results are shown in Table 6.

Claims (9)

A light emitting device material comprising a compound represented by the following general formula (1) or (2).

(R ^{1 to} R ¹⁶ may be the same as or different from each other, hydrogen, alkyl group, cycloalkyl group, heterocyclic group, alkenyl group, cycloalkenyl group, alkynyl group, alkoxy group, alkylthio group, aryl ether group, aryl thioether group, an aryl group, a heteroaryl group, halogen, a carbonyl group, a carboxyl group, an oxycarbonyl group, a carbamoyl group, an amino group, selected from the group consisting of silyl group, and ^{-P (= O) R 17 R} 18 .R 17 And R ¹⁸ represents an aryl group or a heteroaryl group, R ^{1 to} R ⁸ and R ^{9 to} R ¹⁶ may form a ring with adjacent substituents, and X is represented by the general formula (5). a group, Y is a group represented by the general formula (4) .L ¹ is a single bond, a substituted or unsubstituted aromatic ring group having 6 to 40 ants Ren group or a substituted or .L ² representing a heteroarylene group unsubstituted carbon atoms 2 to 40 is a single bond, residues derived from a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, or substituted, Alternatively, it represents a residue derived from an unsubstituted heteroaryl group having 2 to 14 nuclear carbon atoms, HAr ¹ and HAr ² represent a substituted or unsubstituted heteroaryl group having an electron-accepting nitrogen, R ^{19 to} R ^21. Is the same as R ^{1 to} R ^16. m is 1 when L ² is a single bond, and otherwise represents an integer of 1 to 5. HAr ¹ may be the same or different. When m is 2 to 5, HAr ² may be the same or different from each other, and X and Y are not the same group.) HAr ¹ is a substituted or unsubstituted pyridyl group, substituted or unsubstituted pyrimidyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted quinolinyl group or a substituted or unsubstituted isoquinolinyl group claim 1 Symbol placement, Light emitting device material. Or L ² is a single bond, the light emitting device material according to claim 1 or 2, wherein the residue derived from phenyl groups. HAr ² is a substituted or unsubstituted pyridyl group, substituted or unsubstituted pyrimidyl group, a substituted or unsubstituted pyrazinyl group, a substituted or unsubstituted quinolinyl group, claims 1-3 are substituted or unsubstituted isoquinolinyl group The light emitting element material in any one of these. A light emitting device having an organic layer between an anode and a cathode and emitting light by electrical energy, wherein the organic layer contains the light emitting device material according to any one of claims 1 to 4. . A light emitting device in which at least a light emitting layer and an electron transport layer are present between an anode and a cathode and emits light by electric energy, wherein the electron transport layer comprises the light emitting device material according to any one of claims 1 to 5. . The electron transport layer further contains a donor compound, the donor compound is an alkali metal, an inorganic salt containing an alkali metal, an alkali metal-organic complex, an alkaline earth metal, an inorganic salt containing an alkaline earth metal, The light-emitting element according to claim 6, which is a complex of an alkaline earth metal and an organic substance. The light emitting device according to any one of claims 5 to 7 , further comprising a hole transport layer between the anode and the cathode, wherein the hole transport layer contains a material having a carbazole skeleton. The light emitting device according to any one of claims 5 to 7 , further comprising a hole transport layer between the anode and the cathode, wherein the hole transport layer contains a material having a triphenylene skeleton.