JPWO2018180465A1 - Organic electroluminescent device material and organic electroluminescent device - Google Patents

Abstract

Provided are a practically useful organic EL device having high efficiency and high driving stability and a compound for an organic electroluminescent device suitable for the device. This compound for an organic electroluminescent device is represented by the general formula (1), has a skeleton structure in which an aromatic hydrocarbon group and an aromatic heterocyclic group are connected, and has a molecular weight of 500 to 1500 excluding the substituent. And the number of conformations generated by the conformational search calculation of the skeleton structure is 9 to 200,000. In the formula, HetAr is an aromatic heterocyclic group having 3 to 24 carbon atoms such as an indolocarbazole group, and Ar0 is an aromatic hydrocarbon group, an aromatic heterocyclic group, or a combination of these aromatic rings. A linked aromatic group, and z is 2-5.

Description

  The present invention relates to a material for an organic electroluminescent device, an organic electroluminescent device film, and an organic electroluminescent device (hereinafter, referred to as an organic EL device). More specifically, the present invention uses a compound having a specific range of conformation numbers. Organic EL element materials.

By applying a voltage to the organic EL element, holes are injected from the anode and electrons are injected from the cathode into the light emitting layer. Then, in the light emitting layer, the injected holes and electrons are recombined to generate excitons. At this time, singlet excitons and triplet excitons are generated at a ratio of 1: 3 according to the statistical rule of electron spin. It is said that the internal quantum efficiency of a fluorescent organic EL device using light emission by singlet excitons is limited to 25%. On the other hand, in a phosphorescent organic EL device using light emission by triplet excitons, it is known that the internal quantum efficiency can be increased to 100% when intersystem crossing is efficiently performed from singlet excitons. Have been.
However, as for the phosphorescent organic EL device, it is a technical problem to extend the lifetime.

More recently, highly efficient organic EL devices using delayed fluorescence have been developed. For example, Patent Document 1 discloses an organic EL element using a TTF (Triplet-Triplet Fusion) mechanism, which is one of the mechanisms of delayed fluorescence. The TTF mechanism utilizes a phenomenon in which a singlet exciton is generated by collision of two triplet excitons, and is considered to theoretically increase the internal quantum efficiency to 40%. However, since the efficiency is lower than that of a phosphorescent organic EL device, further improvement in efficiency is required.
On the other hand, Patent Document 2 discloses an organic EL device using a TADF (Thermally Activated Delayed Fluorescence) mechanism. The TADF mechanism utilizes the phenomenon that the inverse intersystem crossing from a triplet exciton to a singlet exciton occurs in a material having a small energy difference between the singlet level and the triplet level. It is believed that it can be increased to 100%. However, as in the case of phosphorescent devices, there is a demand for further improvement in the life characteristics.

WO2010 / 134350 No. WO2011 / 070963 No. WO2008 / 056746 No. JP 2003-133075 A WO2013 / 062075 No. US Published 2014/0374728 US Published 2014/0197386 US Publication 2015/0001488 WO2011 / 136755 issue

  Patent Document 3 discloses the use of an indolocarbazole compound as a host material. Patent Document 4 discloses the use of a biscarbazole compound as a host material.

  Patent Documents 5 and 6 disclose the use of a biscarbazole compound as a mixed host. Patent Documents 7 and 8 disclose the use of an indolocarbazole compound and a biscarbazole compound as a mixed host.

Patent Document 9 discloses the use of a host material in which a plurality of hosts including an indolocarbazole compound are premixed.
However, none of these are satisfactory, and further improvements are desired. There is no teaching that a compound having a specific range of conformation numbers is used as a material for an organic electroluminescent device. In addition, there is no teaching of a material for an organic electroluminescent device which can produce an organic electroluminescent device by a coating process.

  In order to apply the organic EL device to a display device such as a flat panel display, it is necessary to improve the luminous efficiency of the device and at the same time ensure sufficient stability during driving. The present invention has been made in view of the above circumstances, and has as its object to provide a practically useful organic EL device having high efficiency and high driving stability, and a compound suitable for the device.

  The present inventors have conducted intensive studies and as a result, found that the above-mentioned problems can be solved by using a compound having a specific number of conformations in a specific range as a material for an organic electroluminescent device, thereby completing the present invention. Reached.

ここで、Ar⁰は独立に、置換若しくは未置換の炭素数6〜30の芳香族炭化水素基、置換若しくは未置換の炭素数3〜24の芳香族複素環基、又はこれらの芳香族環が2〜10連結してなる置換若しくは未置換の連結芳香族基を示す。HetArは、置換若しくは未置換の炭素数3〜24の芳香族複素環基を示す。zは2〜5の整数を示す。That is, the present invention has a skeleton structure represented by the general formula (1) in which aromatic rings selected from an aromatic hydrocarbon ring and an aromatic heterocycle are linked, and the skeleton structure excluding the substituent has a molecular weight of 500 The compound for an organic electroluminescent device, wherein the compound has a structure of not less than 1500 and not more than 9 to 200,000 conformations generated by the conformation search calculation of the skeletal structure.

Here, Ar ⁰ is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms, or an aromatic ring thereof. It represents a substituted or unsubstituted linked aromatic group having 2 to 10 links. HetAr represents a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms. z represents an integer of 2 to 5.

ここで、環Aは2つの隣接環の任意の位置で縮合する式（A2）で表される芳香環を示す。環Bは2つの隣接環の任意の位置で縮合する式（B2）で表される複素環を示す。
R¹〜R³は、それぞれ独立に、シアノ基、炭素数1〜20のアルキル基、炭素数7〜38のアラルキル基、炭素数2〜20のアルケニル基、炭素数2〜20のアルキニル基、炭素数2〜40のジアルキルアミノ基、炭素数12〜44のジアリールアミノ基、炭素数14〜76のジアラルキルアミノ基、炭素数2〜20のアシル基、炭素数2〜20のアシルオキシ基、炭素数1〜20のアルコキシ基、炭素数2〜20のアルコキシカルボニル基、炭素数2〜20のアルコキシカルボニルオキシ基、炭素数1〜20のアルキルスルホニル基、又はL³を示す。As the compound for an organic electroluminescent device, the number of conformations represented by the general formula (2) and generated by the conformation search calculation is larger than 8 × 2 ^{x and not} more than 8 × 4 ^{x + 1} (here, And x is an integer obtained by subtracting 3 from the total number y of Ar ^{1 to} Ar ¹¹ ).

Here, ring A represents an aromatic ring represented by the formula (A2) fused at any position of two adjacent rings. Ring B represents a heterocyclic ring represented by the formula (B2) fused at any position of two adjacent rings.
R ^{1 to} R ³ are each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, C2-40 dialkylamino group, C12-44 diarylamino group, C14-76 diaralkylamino group, C2-20 acyl group, C2-20 acyloxy group, carbon C20 alkoxy group, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, or L ^3.

L¹、L²、L³は独立に、上記式(C2）で表される置換若しくは未置換の連結芳香族基であり、Ar¹〜Ar¹¹はそれぞれ独立に、炭素数6〜30の芳香族炭化水素基、又は炭素数3〜16の芳香族複素環基を示し、これらの芳香族炭化水素基又は芳香族複素環基は、それぞれ独立に置換基を有してもよく、置換基を有する場合の置換基はシアノ基、炭素数1〜20のアルキル基、炭素数7〜38のアラルキル基、炭素数2〜20のアルケニル基、炭素数2〜20のアルキニル基、炭素数2〜40のジアルキルアミノ基、炭素数12〜44のジアリールアミノ基、炭素数14〜76のジアラルキルアミノ基、炭素数2〜20のアシル基、炭素数2〜20のアシルオキシ基、炭素数1〜20のアルコキシ基、炭素数2〜20のアルコキシカルボニル基、炭素数2〜20のアルコキシカルボニルオキシ基、又は炭素数1〜20のアルキルスルホニル基である。但し、Ar¹、Ar²、Ar³、Ar⁴、Ar⁵、Ar⁷およびAr⁹は2価の基であり、Ar⁶はn＋1価の基であり、Ar⁸はm＋1価の基であり、Ar¹⁰はk＋1価の基であり、Ar¹¹は1価の基である。
L¹、L²、L³のうち少なくとも1つはAr¹〜Ar¹¹の総数は2以上であり、L¹、L²及びL³におけるAr¹〜Ar¹¹の総数ｙは3以上である。
a、b、cは置換数を示し、それぞれ独立に0〜2の整数を示す。d、e、f、g、h、i、jは繰り返し数を示し、それぞれ独立に0〜5の整数を示す。k、m、nは置換数を示し、それぞれ独立に0〜5の整数を示す。）

L ¹ , L ² and L ³ are each independently a substituted or unsubstituted linked aromatic group represented by the above formula (C2), and Ar ^{1 to} Ar ¹¹ are each independently an aromatic group having 6 to 30 carbon atoms. Represents an aromatic hydrocarbon group or an aromatic heterocyclic group having 3 to 16 carbon atoms, and these aromatic hydrocarbon groups or aromatic heterocyclic groups may each independently have a substituent; When having a substituent, a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, and 2 to 40 carbon atoms Dialkylamino group, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, and having 1 to 20 carbon atoms An alkoxy group, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or 1 to 20 carbon atoms An alkylsulfonyl group. However, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁷ and Ar ⁹ are divalent groups, Ar ⁶ is an n + 1 monovalent group, Ar ⁸ is an m + 1 monovalent group, Ar ¹⁰ is a k + 1 monovalent group, and Ar ¹¹ is a monovalent group.
At least one of L ^1, L ^2, L ³ is the total number of Ar ¹ to Ar ¹¹ is 2 or more, the total number y of Ar ¹ to Ar ¹¹ in the L ^1, L ² and L ³ is 3 or more.
a, b and c each represent the number of substitutions, and each independently represents an integer of 0 to 2. d, e, f, g, h, i, and j indicate the number of repetitions, and each independently indicate an integer of 0 to 5. k, m, and n each represent the number of substitutions, and each independently represents an integer of 0 to 5. )

ここで、環Dは2つの隣接環の任意の位置で縮合する式（D3）で表される芳香環を示す。環Eは2つの隣接環の任意の位置で縮合する式（E3）で表される複素環を示す。L¹、L²は一般式（2）と同意であるが、L¹、L²の少なくとも一方中のAr⁶は、置換又は未置換の炭素数10〜17の縮合環基を示す。A preferred embodiment of the general formula (2) is the general formula (3).

Here, ring D represents an aromatic ring represented by formula (D3) condensed at any position of two adjacent rings. Ring E represents a heterocyclic ring represented by the formula (E3) fused at any position of two adjacent rings. L ¹ and L ² have the same meaning as in formula (2), but Ar ^{6 in} at least one of L ¹ and L ² represents a substituted or unsubstituted fused ring group having 10 to 17 carbon atoms.

ここでVとWは、それぞれ独立に、単結合、-C-、-CR、C(R)₂、NR、N-、O、又はSを表す。Rは、それぞれ独立に、シアノ基、炭素数1〜20のアルキル基、炭素数7〜38のアラルキル基、炭素数2〜20のアルケニル基、炭素数2〜20のアルキニル基、炭素数2〜40のジアルキルアミノ基、炭素数12〜44のジアリールアミノ基、炭素数14〜76のジアラルキルアミノ基、炭素数2〜20のアシル基、炭素数2〜20のアシルオキシ基、炭素数1〜20のアルコキシ基、炭素数2〜20のアルコキシカルボニル基、炭素数2〜20のアルコキシカルボニルオキシ基、又は炭素数1〜20のアルキルスルホニル基を示す。Ar ^{6 in} at least one of L ¹ and L ² in the general formula (2) or (3) can be a group represented by the following formula (C3) or formula (C4).

Here, V and W each independently represent a single bond, —C—, —CR, C (R) ₂ , NR, N—, O, or S. R is each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, 40 dialkylamino group, C12-44 diarylamino group, C14-76 diaralkylamino group, C2-C20 acyl group, C2-C20 acyloxy group, C1-C20 An alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyl group having 1 to 20 carbon atoms.

ここでXはNR、N-、O、又はSを表す。Rは、式(C3)と同意である。

Here, X represents NR, N-, O, or S. R has the same meaning as in formula (C3).

Preferred embodiments of L ¹ and L ² in the general formula (2) or (3) and preferred compounds for organic electroluminescent devices are shown below.
1) d, e, f, and g in at least one of L ¹ and L ² are all 0;
2) at least one of L ¹ and L ² has at least one partial structure represented by the formula (4);

4) L¹、L²のどちらか一方に式（5）で示される部分構造を持ち、他方に式（6）で示される部分構造を有し、配座探索計算により生成される立体配座の数が200〜200000個となる構造を有すること、

5) L¹、L²の少なくとも一方に、式（7）で示される部分構造を有し、配座探索計算により生成される立体配座の数が200〜200000個となる構造を有すること。

3) A structure in which at least one of L ¹ and L ² has at least one partial structure represented by the formula (5) and the number of conformations generated by the conformation search calculation is 50 to 200,000 Having

4) One of L ¹ and L ² has a partial structure represented by formula (5) and the other has a partial structure represented by formula (6), and the conformation generated by the conformational search calculation Having a structure in which the number of is 200 to 200,000,

5) At least one of L ¹ and L ² has a partial structure represented by the formula (7) and a structure in which the number of conformations generated by the conformation search calculation is 200 to 200,000.

  Further, the present invention is a material for an organic electroluminescent device comprising at least one of the above compounds for an organic electroluminescent device.

  Further, the present invention provides an organic electroluminescent device material comprising at least one compound of the above organic electroluminescent device and at least one compound selected from indolocarbazole compounds having a nitrogen-containing aromatic 6-membered ring structure. is there.

ここで、環Fは2つの隣接環の任意の位置で縮合する式（F8）で表される芳香環を示す。環Gは2つの隣接環の任意の位置で縮合する式（G8）で表される複素環を示す。式（8）および式（G8）中の一方のArは、置換若しくは未置換の炭素数6〜30の芳香族炭化水素基、置換若しくは未置換の炭素数3〜16の芳香族複素環基、又はこれらの芳香族環が2〜10連結してなる置換若しくは未置換の連結芳香族基を示し、他方のArは式(9)で表される含窒素芳香族6員環構造含有基である。

ここでYは、N、CH、又はCAr’で表され、少なくとも一つはNである。Ar’は独立に、置換若しくは未置換の炭素数6〜30の芳香族炭化水素基、置換若しくは未置換の炭素数3〜16の芳香族複素環基、又はこれらの芳香族環が2〜10連結してなる置換若しくは未置換の連結芳香族基を示す。The indolocarbazole compound having a nitrogen-containing aromatic six-membered ring structure includes a compound represented by the general formula (8).

Here, ring F represents an aromatic ring represented by the formula (F8) condensed at any position of two adjacent rings. Ring G represents a heterocyclic ring represented by the formula (G8) fused at an arbitrary position on two adjacent rings. Ar in the formula (8) and the formula (G8) is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, Or a substituted or unsubstituted linked aromatic group in which these aromatic rings are linked by 2 to 10, and the other Ar is a nitrogen-containing aromatic 6-membered ring structure-containing group represented by the formula (9). .

Here, Y is represented by N, CH, or CAr ′, and at least one is N. Ar 'is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, or 2 to 10 of these aromatic rings. It represents a substituted or unsubstituted linked aromatic group which is linked.

ここで、pは０〜５の整数を示す。In the general formula (8), one Ar is a phenyl group, a biphenyl group, or a terphenyl group, and in the general formula (9), Ar ′ is an aromatic hydrocarbon group represented by the formula (10), or It is preferably a connecting aromatic group.

Here, p shows the integer of 0-5.

  Further, the present invention is an organic electroluminescent device including an organic layer comprising the above-mentioned material for an organic electroluminescent device.

  In addition, the present invention is a composition for an organic electroluminescent device obtained by dissolving or dispersing the above-mentioned material for an organic electroluminescent device in a solvent. Further, the present invention is an organic electroluminescent device including an organic layer comprising a coating film of the composition for an organic electroluminescent device.

  Examples of the organic layer include at least one layer selected from a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, a hole-blocking layer, and an electron-blocking layer. It is preferred that This light emitting layer can contain a light emitting dopant material.

The compound for an organic electroluminescent device of the present invention has a structure in which a plurality of aromatic rings including an aromatic heterocycle are connected, and can have various three-dimensional conformations, and thus has a small conformation. A film having lower crystallinity and higher amorphous stability than a material having a structure can be formed.
When the compound for an organic electroluminescent device of the present invention is a compound having an indolocarbazole skeleton, the material for an organic electroluminescent device having high stability in oxidation, reduction, active state of excitons, and high heat resistance Thus, the organic electroluminescent device using the organic thin film formed therefrom exhibits high luminous efficiency and driving stability.
When the material for an organic electroluminescent device of the present invention is a mixture containing the compound for an organic electroluminescent device of the present invention, by using the mixture in the same organic electroluminescent device layer, holes and electrons in the layer are formed. The carrier balance can be adjusted, and a higher performance organic EL device can be realized. Furthermore, since a film having high amorphous stability can be formed by the compound for an organic electroluminescent device of the present invention, the number of conformations of the compound to be mixed may be small.
In addition, since the material for an organic electroluminescent device of the present invention can have various three-dimensional structures as described above, packing between molecules is weak and solubility in an organic solvent is high. Therefore, this material is also adaptable to the coating process.

FIG. 2 is a schematic cross-sectional view showing one example of an organic EL device.

Hereinafter, embodiments for carrying out the present invention will be described in detail.
The compound for an organic electroluminescent device of the present invention is represented by the above general formula (1). And has a skeleton structure in which an aromatic ring selected from an aromatic hydrocarbon ring and an aromatic heterocycle are connected, and the molecular weight of the skeleton structure excluding a substituent that replaces the aromatic ring is 500 or more and 1500 or less, The number of conformations generated by the conformation search calculation of this skeletal structure is 9 to 200,000.
Within this range, both amorphous stability and charge transportability and luminescence can be achieved, and an excellent organic electroluminescent device can be obtained.

  The compound for an organic electroluminescent device of the present invention has a skeleton structure in which aromatic rings of aromatic groups selected from an aromatic hydrocarbon group and an aromatic heterocyclic group are connected by a direct bond. It may have non-aromatic substituents. That is, the skeletal structure referred to in the present specification is composed of only an aromatic ring and does not include a substituent substituting the same. The skeletal structure may be linear or branched. Note that the substituent such as aralkyl is included in the substituent because the aromatic ring is not directly connected by a bond.

  The molecular weight of the skeletal structure is 500 to 1500, but if the molecular weight is too low, the amorphous stability of the material may be reduced. If the molecular weight is too high, the heating temperature required for vapor deposition to form a film may be reduced. And the likelihood of material degradation is increased. Therefore, the range of the molecular weight is 500 to 1500, preferably 600 to 1300, and more preferably 700 to 1100.

  The compound for an organic electroluminescent device of the present invention has a structure in which the number of conformations generated by the conformation search calculation is 9 to 200,000. If the number of conformations is too low, the amorphous stability of the material may be reduced. On the other hand, if the number of conformations is too large, the volume fraction of the structure relating to charge transport and light emission is reduced, so that the charge transport property and light-emitting property are deteriorated, and an excellent organic electroluminescent device is not obtained. Therefore, the range of the number of conformations is 9 to 200,000, preferably 50 to 150,000, and more preferably 200 to 50,000.

  Here, the conformation refers to a locally stable structure that can be taken depending on the bonding rotation and the bonding direction of the molecule, and a plurality of conformations generated by the conformational search calculation are in a relationship of a conformational isomer with each other. is there. The conformational search can be easily determined by performing calculations by the molecular force field method using software such as CONFLEX (manufactured by CONFLEX) or MacroModel (manufactured by Schrodinger). it can. Preferred specific calculation methods are described in Examples. Here, the number of conformations referred to in the present specification is understood to be calculated for the above skeletal structure.

In the general formula (1), Ar ⁰ is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms, or Represents a substituted or unsubstituted linked aromatic group having 2 to 10 linked aromatic rings.
Here, the connected aromatic group is a group having a structure in which aromatic rings of an aromatic hydrocarbon group and an aromatic heterocyclic group are connected by a direct bond, and the aromatic rings constituting the same are the same. May be different, and may be linear or branched, and may have a substituent.

Specific examples of Ar ⁰ include benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, trindene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene , Tetraphene, tetracene, preyaden, picene, perylene, pentaphene, pentacene, tetraphenylene, coranthrene, helicene, hexaphene, rubicene, coronene, trinaphthylene, heptafen, pyranthrene, furan, benzofuran, isobenzofuran, xanthene, oxathrene, dibenzofuran, peri Xanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxatiin, thionaphthene, isothia Naphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazane, pyridine, pyrazine, pyrimidine, pyridazine, triazine, indolizine, indole, indoloindole, indolocarbazole , Isoindole, indazole, purine, quinolidine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carboline, phenotelrazine, phenotelrazine Gin, phenothiazine, phenoxazine, antilysine, benzothiazole, Down zone imidazole, benzoxazole, benzisoxazole, or aromatic compounds such benzisothiazole include groups formed by removing a hydrogen. Preferably hydrogen from benzene, naphthalene, anthracene, triphenylene, pyrene, pyridine, pyrazine, pyrimidine, pyridazine, triazine, carbazole, indole, indoloindole, indolocarbazole, dibenzofuran, dibenzothiophene, quinoline, isoquinoline, quinoxaline, quinazoline or naphthyridine Is a group generated except for

  In the general formula (1), HetAr represents a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms. Specific examples thereof include furan, benzofuran, isobenzofuran, xanthene, oxathrene, dibenzofuran, perixanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxatiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, Pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazane, pyridine, pyrazine, pyrimidine, pyridazine, triazine, indolizine, indole, isoindole, indazole, purine, quinolidine, isoquinoline, carbazole, indoloindole, india Locarbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnori , Quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carboline, phenotelrazine, phenoselenazine, phenothiazine, phenoxazine, antilysine, benzothiazole, benzimidazole, benzoxazole, benzisoxazole, or benzisothiazole And the like, which are formed by removing hydrogen from an aromatic heterocyclic compound. Preferably, it is a group formed by removing hydrogen from pyridine, pyrazine, pyrimidine, pyridazine, triazine, carbazole, indole, indoloindole, indolocarbazole, dibenzofuran, dibenzothiophene, quinoline, isoquinoline, quinoxaline, quinazoline or naphthyridine. Since HetAr is a z-valent group, the number of removed hydrogens is z.

  In the general formula (1), z represents an integer of 2 to 5, but is more preferably an integer of 2 to 4 in view of amorphous stability and charge transporting properties.

  Preferred examples of the compound for an organic electroluminescent device of the present invention include a compound represented by the above general formula (2) or (3).

  In the general formula (2), ring A represents an aromatic ring represented by the formula (A2) condensed at any position of two adjacent rings. Ring B represents a pyrrolidine ring represented by the formula (B2) condensed at any position of two adjacent rings.

When L ¹ , L ² and R ^{1 to} R ³ are L ³ , L ³ is independently represented by the formula (C2).
Ar ^{1 to} Ar ¹¹ each independently represent an aromatic hydrocarbon group having 6 to 30 carbon atoms, or an aromatic heterocyclic group having 3 to 16 carbon atoms, and these aromatic hydrocarbon groups or aromatic heterocyclic groups May each independently have a substituent, and in the case of having a substituent, the substituent is a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, and having 2 to 20 carbon atoms. Alkenyl group, alkynyl group having 2 to 20 carbon atoms, dialkylamino group having 2 to 40 carbon atoms, diarylamino group having 12 to 44 carbon atoms, diaralkylamino group having 14 to 76 carbon atoms, acyl having 2 to 20 carbon atoms Group, an acyloxy group having 2 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms It is. Here, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁷ and Ar ⁹ are divalent groups, Ar ⁶ is an n + 1 monovalent group, and Ar ⁸ is an m + 1 monovalent group. , Ar ¹⁰ is a k + 1 monovalent group, and Ar ¹¹ is a monovalent group.
L ^1, at least one of L ^2, L ³ is the total number of Ar ¹ to Ar ¹¹ is 2 or more. The total number y of Ar ^{1 to} Ar ¹¹ in L ¹ , L ² , and L ³ is 3 or more.
d, e, f, g, h, i, j indicate the number of repetitions, each independently represents an integer of 0 to 5, preferably an integer of 0 to 4, more preferably an integer of 0 to 3 is there. k, m, and n each represent the number of substitutions, and each independently represents an integer of 0 to 5, preferably an integer of 0 to 4, and more preferably an integer of 0 to 2.
The total number of Ar1 to Ar11 can be easily calculated from the numbers d to k and m to n in the formula (C2).

R ^{1 to} R ³ are each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, C2-40 dialkylamino group, C12-44 diarylamino group, C14-76 diaralkylamino group, C2-20 acyl group, C2-20 acyloxy group, carbon C20 alkoxy group, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, or the L ^3.
a, b, and c each represent the number of substitutions, and each independently represents an integer of 0 to 2, preferably an integer of 0 to 1.

Regarding the compound represented by the general formula (2), the number of conformations generated by the conformational search calculation is preferably larger than 8 × 2 ^{× and not} more than 8 × 4 ^{× + 1} , more preferably the 8 × 2 ^{x + 1} pieces are at greater than 8 × 4 ^{x + 1} or less, still more preferably ^{8 × 2 x + 1 4 ×} 8 x or less greater than one.
Here, x is an integer obtained by subtracting 3 from the total number y of Ar ^{1 to} Ar ¹¹ , and x is preferably 1 to 7, and more preferably 2 to 5. Here, the total number y of the Ar ¹ to Ar ¹¹ is understood to be the sum of the total number of Ar ¹ to Ar ¹¹ for L ^1, L ^2, and L ^3.

In the general formula (2), Ar ^{1 to} Ar ^{11 each} represent an aromatic hydrocarbon group having 6 to 30 carbon atoms or an aromatic heterocyclic group having 3 to 16 carbon atoms. Specific examples thereof include benzene and pentalene. , Indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, tridene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene, tetraphen, tetracene, preiaden, picene, Perylene, pentaphene, pentacene, tetraphenylene, coranthrylene, helicene, hexaphene, rubicene, coronene, trinaphthylene, heptafen, pyranthrene, furan, benzofuran, isobenzofuran, xanthene, oxathrene, dibenzofuran, periki Entenoxanthen, thiophene, thioxanthene, thianthrene, phenoxatiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazane, pyridine, pyrazine, Pyrimidine, pyridazine, triazine, indolizine, indole, isoindole, indazole, purine, quinolidine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, Phenanthroline, phenazine, carboline, phenotelrazine, phenoselenazine, pheno Examples include groups generated by removing hydrogen from an aromatic compound such as thiazine, phenoxazine, antilysine, benzothiazole, benzimidazole, benzoxazole, benzoisoxazole, or benzoisothiazole. Preferably produced by removing hydrogen from benzene, naphthalene, anthracene, triphenylene, pyrene, pyridine, pyrazine, pyrimidine, pyridazine, triazine, carbazole, indole, indoloindole, dibenzofuran, dibenzothiophene, quinoline, isoquinoline, quinoxaline, quinazoline or naphthyridine. Group.

In the general formula (3), ring D represents an aromatic ring represented by the formula (D3) condensed at any position of two adjacent rings. Ring E represents a pyrrolidine ring represented by formula (E3) condensed at any position of two adjacent rings. L ¹ and L ² have the same meanings as in the general formula (2), but Ar ^{6 in} one of them represents an n + 1-valent substituted or unsubstituted fused ring group having 10 to 17 carbon atoms.

Ar ⁶ in L ¹ and L ² in the general formula (3) is desirably represented by the above formula (C3). In the formula, V and W each independently represent a single bond, -C-, -CR, C (R) ₂ , NR, N-, O, or S, and preferably, one of V and W is a single bond. A bond, and the other is N-, O, or S. Here, R is each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, A dialkylamino group having 2 to 40, a diarylamino group having 12 to 44 carbon atoms, a diaralkylamino group having 14 to 76 carbon atoms, an acyl group having 2 to 20 carbon atoms, an acyloxy group having 2 to 20 carbon atoms, and having 1 carbon atom An alkoxy group having 2 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyl group having 1 to 20 carbon atoms.

It is preferable that at least one of L ¹ and L ² in the general formula (2) or the general formula (3) has at least one partial structure represented by the above formula (4), and preferably the partial structure is More preferably, it is represented by the above formula (5), and the partial structure is represented by the above formula (7). The above partial structure may be at the terminal, at the middle or at the tip, and when it is at the terminal, one bond bonds to hydrogen.

Further, ^one of L ¹ and L ² may have a partial structure represented by the above formula (5), and the other may have a partial structure represented by the above formula (6).

  Examples of the compound for an organic electroluminescent device represented by the general formula (2) are shown below, but are not limited to these exemplified compounds.

The compound for an organic electroluminescent device of the present invention can be used alone as a material for an organic electroluminescent device.However, by using a plurality of compounds for an organic electroluminescent device of the present invention, or by mixing with other compounds, an organic compound can be used. By using it as a material for an electroluminescent element, its function can be further improved or a lacking property can be supplemented.
Preferred compounds that can be used as a mixture with the compound for an organic electroluminescent device of the present invention are indolocarbazole compounds having a nitrogen-containing aromatic 6-membered ring structure. As the indolocarbazole compound having a nitrogen-containing aromatic six-membered ring structure, there is a compound having one or two indolocarbazole rings. Incidentally, when the indolocarbazole compound having the nitrogen-containing aromatic 6-membered ring structure has a number of conformations larger than 8 × 2 ^x and 8 × 4 ^{x + 1} or less, the organic compound of the present invention is used. It is understood that it is also a compound for an electroluminescent element.

Indolocarbazole compounds having a nitrogen-containing aromatic six-membered ring structure include compounds represented by the above general formula (8).
In formula (8), ring F represents an aromatic ring represented by formula (F8) condensed at any position of two adjacent rings. Ring G represents a heterocyclic ring represented by the formula (G8) fused at an arbitrary position on two adjacent rings. Ar in the formula (8) and the formula (G8) is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, Or a substituted or unsubstituted linked aromatic group in which these aromatic rings are linked by 2 to 10, and the other Ar is a nitrogen-containing aromatic 6-membered ring structure-containing group represented by the formula (9). .

  When Ar is the above aromatic hydrocarbon group, aromatic heterocyclic group, or linked aromatic group, specific examples thereof include benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, Phenanthrene, anthracene, trinedene, fluoranthene, acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene, tetraphene, tetracene, pleiaden, picene, perylene, pentaphene, pentacene, tetraphenylene, coranthrylene, helicene, hexaphene, rubicene, Coronene, trinaphthylene, heptafen, pyranthrene, furan, benzofuran, isobenzofuran, xanthene, oxathrene, dibenzofuran, perixanthenoxanthene, thiophene, Oxanthene, thianthrene, phenoxathiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellurazole, selenazole, thiazole, isothiazole, oxazole, furazane, pyridine, pyrazine, pyrimidine, pyridazine, triazine, Indolidine, indole, isoindole, indazole, purine, quinolidine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline, cinnoline, quinoline, pteridine, phenanthridine, acridine, perimidine, phenanthroline, phenazine, carbolin, Phenotellurazine, phenoselenazine, phenothiazine, phenoxazine, anti Examples include a group obtained by removing hydrogen from an aromatic compound such as lysine, benzothiazole, benzimidazole, benzoxazole, benzoisoxazole, or benzoisothiazole. Preferably produced by removing hydrogen from benzene, naphthalene, anthracene, triphenylene, pyrene, pyridine, pyrazine, pyrimidine, pyridazine, triazine, carbazole, indole, indoloindole, dibenzofuran, dibenzothiophene, quinoline, isoquinoline, quinoxaline, quinazoline or naphthyridine. Group.

  When Ar is a nitrogen-containing aromatic 6-membered ring-containing group represented by the formula (9), Y is represented by N, CH, or CAr ', and at least one is N. Ar 'is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, or 2 to 10 of these aromatic rings. Shows a substituted or unsubstituted linked aromatic group formed by linking. Specific examples thereof include benzene, pentalene, indene, naphthalene, azulene, heptalene, octalene, indacene, acenaphthylene, phenalene, phenanthrene, anthracene, trinedene, and fluoranthene. , Acephenanthrylene, aceanthrylene, triphenylene, pyrene, chrysene, tetraphen, tetracene, pleiadene, picene, perylene, pentaphen, pentacene, tetraphenylene, coranthrylene, helicene, hexaphen, rubicene, coronene, trinaphthylene, heptaphen, pyranthrene Furan, benzofuran, isobenzofuran, xanthene, oxathrene, dibenzofuran, perixanthenoxanthene, thiophene, thioxanthene, thianthrene, phenoxatiin, thionaphthene, isothianaphthene, thiophthene, thiophanthrene, dibenzothiophene, pyrrole, pyrazole, tellrazole, Selenazole, thiazole, isothiazole, oxazole, furazane, pyridine, pyrazine, pyrimidine, pyridazine, triazine, indolizine, indole, isoindole, indazole, purine, quinolidine, isoquinoline, carbazole, imidazole, naphthyridine, phthalazine, quinazoline, benzodiazepine, quinoxaline , Cinnoline, quinoline, pteridine, phenanthridine, acridine, perimi Gin, phenanthroline, phenazine, carboline, phenotelrazine, phenoselenazine, phenothiazine, phenoxazine, antilysine, benzothiazole, benzimidazole, benzoxazole, benzoisoxazole, or aromatic compounds such as benzoisothiazole, except for hydrogen The resulting groups are mentioned. Preferably produced by removing hydrogen from benzene, naphthalene, anthracene, triphenylene, pyrene, pyridine, pyrazine, pyrimidine, pyridazine, triazine, carbazole, indole, indoloindole, dibenzofuran, dibenzothiophene, quinoline, isoquinoline, quinoxaline, quinazoline or naphthyridine. Group. More preferably, it is a group represented by the formula (10), and p represents an integer of 0 to 5.

  Specific structural examples of the indolocarbazole compound having a nitrogen-containing aromatic six-membered ring structure are shown below, but the invention is not limited to these exemplary compounds.

  The compound or material for an organic electroluminescent device of the present invention is an organic layer such as a hole injecting layer, a hole transporting layer, an electron transporting layer, an electron injecting layer, a hole blocking layer or an electron blocking layer which constitutes the organic electroluminescent device. Although it can be used as a material, among them, it is preferable to use it as a hole transport layer, an electron blocking layer, a light emitting layer, an electron transport layer, or a hole blocking layer material. More preferably, it is used as a hole blocking layer material.

  When a film is formed by a vapor deposition process using a material for an organic electroluminescent device, an organic layer may be formed by vapor deposition from a vapor deposition source alone, or an organic layer may be vapor-deposited from a different vapor deposition source simultaneously with other compounds. Layers can also be formed. Alternatively, the organic layer can be formed by pre-mixing with another compound before vapor deposition to form a pre-mixture, and depositing the pre-mixture simultaneously from one vapor deposition source. In this case, it is preferable that the compound used for the pre-mixing and the compound for an organic electroluminescent device of the present invention have a temperature difference of not more than 30 ° C. at which a desired vapor pressure is obtained.

  The organic electroluminescent element material can be applied to various coating processes such as a spin coating method, a bar coating method, a spray method, an ink jet method, and a printing method. In this case, a solution in which the material for an organic electroluminescent device of the present invention is dissolved or dispersed in a solvent (also referred to as a composition for an organic electroluminescent device) is applied onto a substrate, and then the solvent is volatilized by heating and drying. An organic layer can be formed. At this time, one type of solvent may be used, or a mixture of two or more types may be used. Further, the solution may contain, as compounds other than the present invention, azine compounds, luminescent dopant materials such as phosphorescence, fluorescence, delayed fluorescence, additives, and the like.

  Next, the structure of an element manufactured using the material of the present invention will be described with reference to the drawings, but the structure of the organic electroluminescent element of the present invention is not limited thereto.

  FIG. 1 is a sectional view showing a structural example of a general organic electroluminescent device used in the present invention, wherein 1 is a substrate, 2 is an anode, 3 is a hole injection layer, 4 is a hole transport layer, and 5 is light emission. Layer, 6 represents an electron transport layer, and 7 represents a cathode. The organic EL device of the present invention may have an exciton blocking layer adjacent to the light emitting layer, or may have an electron blocking layer between the light emitting layer and the hole injection layer. The exciton blocking layer can be inserted on either the anode side or the cathode side of the light emitting layer, or both can be inserted simultaneously. The organic electroluminescent device of the present invention has an anode, a light emitting layer, and a cathode as essential layers, but preferably has a hole injection transport layer and an electron injection transport layer in addition to the essential layers. It is preferable to have a hole blocking layer between the injection and transport layers. Note that the hole injection / transport layer means one or both of the hole injection layer and the hole transport layer, and the electron injection / transport layer means one or both of the electron injection layer and the electron transport layer.

  1, that is, the cathode 7, the electron transport layer 6, the light-emitting layer 5, the hole transport layer 4, and the anode 2 can be laminated on the substrate 1 in this order. It can be added or omitted.

-substrate-
The organic electroluminescent device of the present invention is preferably supported on a substrate. The substrate is not particularly limited, and may be any substrate that has been conventionally used for an organic electroluminescent element. For example, a substrate made of glass, transparent plastic, quartz, or the like can be used.

-anode-
As the anode material in the organic electroluminescent device, a material made of a metal, an alloy, an electrically conductive compound or a mixture thereof having a large work function (4 eV or more) is preferably used. Specific examples of such an electrode material include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Further, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) that can form a transparent conductive film may be used. For the anode, a thin film may be formed from these electrode materials by a method such as evaporation or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not so required (about 100 μm or more). In the above, a pattern may be formed via a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Alternatively, when a coatable substance such as an organic conductive compound is used, a wet film forming method such as a printing method and a coating method can be used. When light is extracted from the anode, the transmittance is desirably greater than 10%, and the sheet resistance of the anode is preferably several hundred Ω / □ or less. The film thickness depends on the material, but is usually selected in the range of 10 to 1000 nm, preferably 10 to 200 nm.

-cathode-
On the other hand, as the cathode material, a material composed of a metal having a small work function (4 eV or less) (referred to as an electron injecting metal), an alloy, an electrically conductive compound, or a mixture thereof is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O) ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among them, a mixture of an electron injecting metal and a second metal which is a stable metal having a large work function, such as a magnesium / silver mixture, magnesium, / Aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) mixture, lithium / aluminum mixture, aluminum and the like are suitable. The cathode can be manufactured by forming a thin film from these cathode materials by a method such as evaporation or sputtering. The sheet resistance of the cathode is preferably several hundreds Ω / □ or less, and the film thickness is generally selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either the anode or the cathode of the organic electroluminescent element is transparent or translucent, the emission luminance is improved, which is convenient.

  In addition, after forming the metal in the cathode in a thickness of 1 to 20 nm, by forming the conductive transparent material mentioned in the description of the anode thereon, a transparent or translucent cathode can be produced, By applying this, an element in which both the anode and the cathode have transparency can be manufactured.

-Emitting layer-
The light emitting layer is a layer that emits light after excitons are generated by recombination of holes and electrons injected from the anode and the cathode, respectively. The light emitting layer contains a light emitting dopant material and a host material.

  The material for an organic electroluminescent device of the present invention is suitably used as a host material in a light emitting layer. Further, one or more known host materials may be used in combination, but the use amount is preferably 50 wt% or less, and more preferably 25 wt% or less, based on the total of the host materials.

  The material for an organic electroluminescent element can be formed by vapor deposition from a vapor deposition source or by dissolving in a solvent to form a solution, and then coating and drying the hole injecting and transporting layer.

  When an organic layer is formed by vapor-depositing a material for an organic electroluminescent element, other host materials and dopants may be vapor-deposited from a different vapor deposition source together with the material of the present invention, or may be pre-mixed before vapor deposition to prepare By using a mixture, a plurality of host materials and dopants can be simultaneously deposited from one deposition source.

  When a solution of a material for an organic electroluminescent element is applied and dried to form a light emitting layer, it is preferable that a material used for a hole injection transport layer serving as a base has low solubility in a solvent used for a light emitting layer solution.

  As the luminescent dopant material, any of a fluorescent luminescent dopant, a phosphorescent luminescent dopant and a delayed fluorescent luminescent dopant may be used, but from the viewpoint of luminous efficiency, a phosphorescent luminescent dopant and a delayed fluorescent luminescent dopant are preferable. Further, these luminescent dopants may contain only one kind, or may contain two or more kinds of dopants.

  The phosphorescent dopant preferably contains an organometallic complex containing at least one metal selected from ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and gold. Specifically, iridium complexes described in J. Am. Chem. Soc. 2001, 123, 4304 and JP-T-2013-53051 are suitably used, but not limited thereto. In addition, the content of the phosphorescent dopant material is preferably 0.1 to 30% by weight, more preferably 1 to 20% by weight, based on the host material.

The phosphorescent light emitting dopant material is not particularly limited, but specific examples include the following.

  When a fluorescent dopant is used, examples of the fluorescent dopant include, but are not limited to, benzoxazole derivatives, benzothiazole derivatives, benzimidazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, and naphthalimide. Derivative, coumarin derivative, condensed aromatic compound, perinone derivative, oxadiazole derivative, oxazine derivative, aldazine derivative, pyrazine derivative, cyclopentadiene derivative, bisstyrylanthracene derivative, quinacridone derivative, pyrrolopyridine derivative, thiadiazolopyridine derivative, styryl Amine derivatives, diketopyrrolopyrrole derivatives, aromatic dimethylidine compounds, metal complexes of 8-quinolinol derivatives and pyromethene derivatives Body metal complexes, rare earth complexes, such as various metal complexes represented by transition metal complexes, polythiophene, polyphenylene, polyphenylene vinylene polymer compounds such as, organic silane derivatives, and the like. Preferred are condensed aromatic derivatives, styryl derivatives, diketopyrrolopyrrole derivatives, oxazine derivatives, pyrromethene metal complexes, transition metal complexes, or lanthanoid complexes, and more preferably naphthalene, pyrene, chrysene, triphenylene, benzo [c] phenanthrene , Benzo [a] anthracene, pentacene, perylene, fluoranthene, acenaphthofluoranthene, dibenzo [a, j] anthracene, dibenzo [a, h] anthracene, benzo [a] naphthalene, hexacene, naphtho [2,1-f ] Isoquinoline, α-naphthaphenanthridine, phenanthrooxazole, quinolino [6,5-f] quinoline, benzothiophanthrene and the like. These may have an alkyl group, an aryl group, an aromatic heterocyclic group, or a diarylamino group as a substituent. The content of the fluorescent dopant material is preferably from 0.1 to 20%, more preferably from 1 to 10%, based on the host material.

  When using a heat-activated delayed fluorescence emission dopant, as the heat-activated delayed fluorescence emission dopant, metal complexes such as, but not limited to, tin complexes and copper complexes, and indolocarbazole derivatives described in WO2011 / 070963, Examples include cyanobenzene derivatives and carbazole derivatives described in Nature 2012, 492, 234, phenazine derivatives, oxadiazole derivatives, triazole derivatives, sulfone derivatives, phenoxazine derivatives, and acridine derivatives described in Nature Photonics 2014, 8,326. Further, the content of the thermally activated delayed fluorescent light emitting dopant material is preferably 0.1 to 90%, more preferably 1 to 50%, based on the host material.

-Injection layer-
The injection layer is a layer provided between the electrode and the organic layer for driving voltage reduction and emission luminance improvement, and has a hole injection layer and an electron injection layer, between the anode and the light emitting layer or the hole transport layer. And between the cathode and the light emitting layer or the electron transporting layer. An injection layer can be provided as needed.

-Hole blocking layer-
The hole blocking layer has a function of an electron transporting layer in a broad sense, and is made of a hole blocking material having an extremely small ability to transport holes while having a function of transporting electrons. , The probability of recombination of electrons and holes in the light emitting layer can be improved.

  The hole blocking layer preferably contains the material of the present invention, but a known hole blocking layer material can also be used.

-Electron blocking layer-
The electron blocking layer has the function of a hole transporting layer in a broad sense, and can improve the probability of recombination of electrons and holes in the light emitting layer by blocking electrons while transporting holes. .

  As a material of the electron blocking layer, a known electron blocking layer material can be used, and a material of a hole transport layer described later can be used as needed. The thickness of the electron blocking layer is preferably from 3 to 100 nm, more preferably from 5 to 30 nm.

-Exciton blocking layer-
The exciton blocking layer is a layer for preventing excitons generated by recombination of holes and electrons in the light emitting layer from diffusing into the charge transport layer. The light emitting layer can be efficiently confined in the light emitting layer, and the light emitting efficiency of the element can be improved. The exciton blocking layer can be inserted between two adjacent light emitting layers in a device in which two or more light emitting layers are adjacent.

  As a material for the exciton blocking layer, a known exciton blocking layer material can be used. For example, 1,3-dicarbazolylbenzene (mCP) and bis (2-methyl-8-quinolinolato) -4-phenylphenolato aluminum (III) (BAlq) are mentioned.

-Hole transport layer-
The hole transport layer is made of a hole transport material having a function of transporting holes, and the hole transport layer can be provided as a single layer or a plurality of layers.

  The hole transporting material has any of hole injection or transport and electron barrier properties, and may be any of an organic substance and an inorganic substance. For the hole transport layer, any one of conventionally known compounds can be selected and used. Such hole transport materials include, for example, porphyrin derivatives, arylamine derivatives, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives , Oxazole derivatives, styryl anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aniline-based copolymers, conductive polymer oligomers, especially thiophene oligomers, etc., but porphyrin derivatives, arylamine derivatives and styryl It is preferable to use an amine derivative, and it is more preferable to use an arylamine compound.

-Electron transport layer-
The electron transport layer is made of a material having a function of transporting electrons, and the electron transport layer can be provided as a single layer or a plurality of layers.

  The electron transporting material (which may also serve as a hole blocking material) may have a function of transmitting electrons injected from the cathode to the light emitting layer. For the electron transport layer, any one of conventionally known compounds can be selected and used. For example, polycyclic aromatic derivatives such as naphthalene, anthracene, and phenanthroline, and tris (8-quinolinolato) aluminum (III) Derivatives, phosphine oxide derivatives, nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, bipyridine derivatives, quinoline derivatives, oxadiazole derivatives, benzimidazole Derivatives, benzothiazole derivatives, indolocarbazole derivatives and the like. Further, a polymer material in which these materials are introduced into a polymer chain, or a polymer material in which these materials are used as a polymer main chain, can also be used.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples, and can be implemented in various forms without departing from the gist thereof.

Examples 1 to 15, Comparative Examples 1 to 5
Compounds 021, 142, 141, 023, 150, 149, 019, 138, 137, 052, 175, 174, 040, 217, 162 and compounds 901 to 905 for comparison as exemplified as compounds for organic electroluminescent elements , A conformational search calculation was performed. The conformational search calculation is performed by inputting the atomic coordinates and the bonding mode of the calculation target structure into a calculation software called CONFLEX (manufactured by CONFLEX), setting the conformational search range from the locally stable structure to 20 kcal / mol, Calculated by the dynamic method (force field: MMFF94s). Table 1 shows the calculation results of the conformation generated by the conformation search calculation. Note that all of the above compounds have a structure in which aromatic rings are linked and do not have a non-aromatic substituent, so that the compound itself has a skeleton structure containing no substituent.

The compound numbers correspond to the numbers assigned to the exemplified compounds and the numbers assigned to the compounds for comparison below.

Example 16
On a glass substrate on which a 110 nm-thick ITO anode was formed, each thin film was laminated by a vacuum deposition method at a degree of vacuum of 4.0 × 10 ⁻⁵ Pa. First, HAT-CN was formed with a thickness of 25 nm as a hole injection layer on ITO, and then NPD was formed with a thickness of 30 nm as a hole transport layer. Next, HT-1 was formed to a thickness of 10 nm as an electron blocking layer. Then, compound 021 as a host and Ir (ppy) ₃ as a light emitting dopant were co-evaporated from different evaporation sources to form a light emitting layer with a thickness of 40 nm. At this time, co-evaporation was performed under evaporation conditions in which the concentration of Ir (ppy) ₃ was 10 wt%. Next, ET-1 was formed to a thickness of 20 nm as an electron transport layer. Further, lithium fluoride (LiF) having a thickness of 1 nm was formed on the electron transport layer as an electron injection layer. Finally, aluminum (Al) was formed as a cathode to a thickness of 70 nm on the electron injection layer to produce an organic EL device.

Examples 17 to 30
In Example 16, it carried out similarly to Example 16 except having used any of compounds 142, 141, 023, 150, 149, 019, 138, 137, 052, 175, 174, 040, 217, or 162 as a host. An organic EL device was manufactured.

Comparative Examples 6 to 10
An organic EL device was fabricated in the same manner as in Example 16, except that any one of the compounds 901, 902, 903, 904, and 905 was used as a host.

When the organic EL devices manufactured in Examples 16 to 30 and Comparative Examples 6 to 10 were connected to an external power supply and applied a DC voltage, an emission spectrum with a maximum wavelength of 530 nm was observed, and Ir (ppy) was observed. It was found that light emission from ₃ was obtained.

Table 2 shows the luminance, drive voltage, and life characteristics of the organic EL devices manufactured in Examples 16 to 30 and Comparative Examples 6 to 10. In Table 2, the voltage and luminance are values at a drive current of 20 mA / cm ² , and are initial characteristics. In Table 2, LT70 is the time required for the luminance to decrease to 70% of the initial luminance when the initial luminance is 9000 cd / m ² , and is a life characteristic. In addition, each characteristic is represented by a relative value with the characteristic of Comparative Example 6 being 100%.

Example 31
On a glass substrate on which a 110 nm-thick ITO anode was formed, each thin film was laminated by a vacuum deposition method at a degree of vacuum of 4.0 × 10 ⁻⁵ Pa. First, HAT-CN was formed with a thickness of 25 nm as a hole injection layer on ITO, and then NPD was formed with a thickness of 30 nm as a hole transport layer. Next, HT-1 was formed to a thickness of 10 nm as an electron blocking layer. Then, compound 021 was used as a first host, compound 409 was used as a second host, and Ir (ppy) ₃ was used as a light-emitting dopant by co-evaporation from different evaporation sources to form a light-emitting layer with a thickness of 40 nm. At this time, co-evaporation was performed under an evaporation condition in which the concentration of Ir (ppy) ₃ was 10 wt% and the weight ratio of the first host and the second host was 60:40. Next, ET-1 was formed to a thickness of 20 nm as an electron transport layer. Further, lithium fluoride (LiF) having a thickness of 1 nm was formed on the electron transport layer as an electron injection layer. Finally, aluminum (Al) was formed as a cathode to a thickness of 70 nm on the electron injection layer to produce an organic EL device.

Examples 32 to 50, Comparative Examples 11 to 14
An organic EL device was fabricated in the same manner as in Example 31, except that the combination of the first host and the second host was changed to the combinations shown in Table 3.

When an organic EL device manufactured in Examples 31 to 50 and Comparative Examples 11 to 14 was connected to an external power supply and a DC voltage was applied, an emission spectrum having a maximum wavelength of 530 nm was observed in each case, and Ir (ppy) was observed. It was found that light emission from ₃ was obtained.

Table 3 shows the luminance, drive voltage, and life characteristics of the organic EL devices manufactured in Examples 31 to 50 and Comparative Examples 11 to 14. In Table 3, the voltage and the luminance are values at a driving current of 20 mA / cm ² , and are initial characteristics. LT90 is the life time characteristic, which is the time required for the luminance to decay to 90% of the initial luminance at an initial luminance of 9000 cd / m ² . Note that all the characteristics are represented by relative values with the characteristics of Comparative Example 11 being 100%.

Example 51
Poly (3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (PEDOT / PSS) as a hole injection layer on a glass substrate with ITO having a thickness of 150 nm, which was subjected to solvent washing and UV ozone treatment: (HC Starck) Co., Ltd., trade name: Crevios PCH8000) was formed to a film thickness of 25 nm. Next, a mixture mixed at a ratio of HT-2: BBPPA = 5: 5 (molar ratio) was dissolved in tetrahydrofuran to prepare a 0.4 wt% solution, and a 20 nm film was formed by spin coating. Next, the solvent was removed on a hot plate at 150 ° C. for 1 hour under anaerobic conditions, and heating and curing were performed. This thermosetting film is a film having a crosslinked structure and is insoluble in a solvent. This thermosetting film is a hole transport layer (HTL). Compound 21 was used as the first host, compound 402 was used as the second host, and Ir (ppy) ₃ was used as the luminescent dopant. The weight ratio of the first host to the second host was 60:40, and the weight ratio of the host: dopant was 60%. A 95: 5 toluene solution (1.0 wt%) was prepared, and a 40 nm film was formed as a light emitting layer by spin coating. Then, using a vacuum deposition apparatus, the Alq ₃ 35 nm, a LiF / Al film was formed by a thickness of 170nm as the cathode to prepare an organic electroluminescent device by sealing the element in a glove box.

Examples 52 to 62, Comparative Examples 15 to 18
In Example 43, an organic electroluminescent device was produced in the same manner as in Example 51, except that the combination of the first host and the second host was changed as shown in Table 4.

When the organic EL devices manufactured in Examples 51 to 62 and Comparative Examples 15 to 18 were connected to an external power supply and applied a DC voltage, an emission spectrum of a maximum wavelength of 530 nm was observed in each case, and Ir (ppy) was observed. It was found that light emission from ₃ was obtained.
Table 4 shows the luminance, drive voltage, and life characteristics of the manufactured organic EL device. In Table 4, the voltage and the luminance are values at a drive current of 20 mA / cm ² , and are initial characteristics. LT90 is the life time characteristic, which is the time it takes for the luminance to decay to 90% of the initial luminance at an initial luminance of 9000 cd / m ² . Note that all the characteristics are represented by relative values with the characteristics of Comparative Example 15 being 100%.

Example 63
Poly (3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (PEDOT / PSS) as a hole injection layer on a glass substrate with ITO having a thickness of 150 nm, which was subjected to solvent washing and UV ozone treatment: (HC Starck) Co., Ltd., trade name: Crevios PCH8000) was formed to a film thickness of 25 nm. Next, a mixture mixed at a ratio of HT-2: BBPPA = 5: 5 (molar ratio) was dissolved in tetrahydrofuran to prepare a 0.4 wt% solution, and a 20 nm film was formed by spin coating. Next, the solvent was removed on a hot plate at 150 ° C. for 1 hour under anaerobic conditions, and heating and curing were performed. This thermosetting film is a film having a crosslinked structure and is insoluble in a solvent. This thermosetting film is a hole transport layer (HTL). The compound 21 was used as the first host, the compound 800 was used as the second host, and Ir (ppy) ₃ was used as the luminescent dopant. The weight ratio of the first host to the second host was 60:40, and the weight ratio of the host: dopant was 60%. A 95: 5 toluene solution (1.0 wt%) was prepared, and a 40 nm film was formed as a light emitting layer by spin coating. Then, using a vacuum deposition apparatus, the Alq ₃ 35 nm, a LiF / Al film was formed by a thickness of 170nm as the cathode to prepare an organic electroluminescent device by sealing the element in a glove box.

Examples 64 to 74, Comparative Examples 19 to 22
In Example 63, an organic electroluminescent device was produced in the same manner as in Example 64, except that the combination of the first host and the second host was changed as shown in Table 5.

When the organic EL devices produced in Examples 63 to 74 and Comparative Examples 19 to 22 were connected to an external power supply and a DC voltage was applied, an emission spectrum with a maximum wavelength of 530 nm was observed, and Ir (ppy) was observed. It was found that light emission from ₃ was obtained.
Table 5 shows the luminance, drive voltage, and life characteristics of the manufactured organic EL device. In Table 5, the voltage and luminance are values at a drive current of 20 mA / cm ² , and are initial characteristics. LT90 is the life time characteristic, which is the time it takes for the luminance to decay to 90% of the initial luminance at an initial luminance of 9000 cd / m ² . In addition, each characteristic is represented by a relative value with the characteristic of Comparative Example 19 being 100%.

  From the above results, when a compound having a conformation number within a specific range is used as a host, the life characteristics are significantly extended as compared with a case where a compound having a conformation number outside the range is used as a host. I understand.

The compounds used in the examples and comparative examples are shown below.

  The organic electroluminescent device using the compound for an organic electroluminescent device of the present invention exhibits high luminous efficiency and driving stability.

1 substrate, 2 anode, 3 hole injection layer, 4 hole transport layer, 5 light emitting layer, 6 electron transport layer, 7 cathode

Claims (21)

Having a skeleton structure in which an aromatic ring selected from an aromatic hydrocarbon ring and an aromatic heterocyclic ring represented by the general formula (1) is connected, and a skeleton structure excluding a substituent having a molecular weight of 500 or more and 1500 or less; A compound for an organic electroluminescent device, wherein the compound has a structure in which the number of conformations generated by the conformation search calculation of the skeleton structure is 9 to 200,000.

Here, Ar ⁰ is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms, or an aromatic ring thereof. It represents a substituted or unsubstituted linked aromatic group having 2 to 10 links. HetAr represents a substituted or unsubstituted aromatic heterocyclic group having 3 to 24 carbon atoms. z represents an integer of 2 to 5. The number of conformations represented by the general formula (2) and generated by the conformation search calculation is greater than 8 × 2 ^{x and not} more than 8 × 4 ^{x + 1} (where x is Ar ^{1 to} Ar ¹¹ The compound for an organic electroluminescent device according to claim 1, wherein the total number is an integer obtained by subtracting 3 from y).

Here, ring A represents an aromatic ring represented by the formula (A2) fused at any position of two adjacent rings. Ring B represents a heterocyclic ring represented by the formula (B2) fused at any position of two adjacent rings.
R ^{1 to} R ³ are each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, C2-40 dialkylamino group, C12-44 diarylamino group, C14-76 diaralkylamino group, C2-20 acyl group, C2-20 acyloxy group, carbon C20 alkoxy group, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, an alkylsulfonyl group having 1 to 20 carbon atoms, or L ^3.
L ¹ , L ² and L ³ are each independently a substituted or unsubstituted linked aromatic group represented by the formula (C2), and Ar ^{1 to} Ar ¹¹ are each independently an aromatic group having 6 to 30 carbon atoms Represents a hydrocarbon group, or an aromatic heterocyclic group having 3 to 16 carbon atoms, and these aromatic hydrocarbon groups or aromatic heterocyclic groups may each independently have a substituent, and have a substituent In this case, the substituent is a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, and having 2 to 40 carbon atoms. Dialkylamino group, diarylamino group having 12 to 44 carbon atoms, diaralkylamino group having 14 to 76 carbon atoms, acyl group having 2 to 20 carbon atoms, acyloxy group having 2 to 20 carbon atoms, alkoxy having 1 to 20 carbon atoms Group, an alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or an alkoxycarbonyl group having 1 to 20 carbon atoms. An alkylsulfonyl group. However, Ar ¹ , Ar ² , Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁷ and Ar ⁹ are divalent groups, Ar ⁶ is an n + 1 monovalent group, Ar ⁸ is an m + 1 monovalent group, Ar ¹⁰ is a k + 1 monovalent group, and Ar ¹¹ is a monovalent group.
At least one of L ^1, L ^2, L ³ is the total number of Ar ¹ to Ar ¹¹ is 2 or more, the total number y of Ar ¹ to Ar ¹¹ in the L ^1, L ² and L ³ is 3 or more.
a, b and c each represent the number of substitutions, and each independently represents an integer of 0 to 2. d, e, f, g, h, i, and j indicate the number of repetitions, and each independently indicate an integer of 0 to 5. k, m, and n each represent the number of substitutions, and each independently represents an integer of 0 to 5. The compound for an organic electroluminescent device according to claim 2, which is represented by the general formula (3).

Here, ring D represents an aromatic ring represented by formula (D3) condensed at any position of two adjacent rings. Ring E represents a heterocyclic ring represented by the formula (E3) fused at any position of two adjacent rings. L ¹ and L ² have the same meaning as in formula (2), but Ar ^{6 in} at least one of L ¹ and L ² represents a substituted or unsubstituted fused ring group having 10 to 17 carbon atoms. 4. The compound for an organic electroluminescent device according to claim 3, wherein Ar ⁶ is represented by the following formula (C3).

Here, V and W each independently represent a single bond, —C—, —CR, C (R) ₂ , NR, N—, O, or S. R is each independently a cyano group, an alkyl group having 1 to 20 carbon atoms, an aralkyl group having 7 to 38 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an alkynyl group having 2 to 20 carbon atoms, 40 dialkylamino group, C12-44 diarylamino group, C14-76 diaralkylamino group, C2-C20 acyl group, C2-C20 acyloxy group, C1-C20 An alkoxycarbonyl group having 2 to 20 carbon atoms, an alkoxycarbonyloxy group having 2 to 20 carbon atoms, or an alkylsulfonyl group having 1 to 20 carbon atoms. 5. The compound for an organic electroluminescent device according to claim 4, wherein the formula (C3) is represented by the following formula (C4).

Here, X represents NR, N-, O, or S. R is equivalent to equation (C3). The compound for an organic electroluminescent device according to claim 2, wherein d, e, f, and g in at least one of L ¹ and L ² are all 0. L ^1, and at least one of L ^2, compound for organic electroluminescent device of claim 2 having at least one partial structure represented by the formula (4).

At least one of L ¹ and L ² has at least one partial structure represented by the formula (5), and has a structure in which the number of conformations generated by the conformation search calculation is 50 to 200,000 The compound for an organic electroluminescent device according to claim 2, wherein:

One of L ¹ and L ² has a partial structure represented by formula (5), and the other has a partial structure represented by formula (6). 3. The compound for an organic electroluminescent device according to claim 2, wherein the compound has a structure in which the number is 200 to 200,000.

At least one of L ¹ and L ² has a partial structure represented by the formula (7), and has a structure in which the number of conformations generated by the conformation search calculation is 200 to 200,000. The compound for an organic electroluminescent device according to claim 2, wherein

  A material for an organic electroluminescent device, comprising at least one of the compounds for an organic electroluminescent device according to claim 1.   12. The material for an organic electroluminescent device according to claim 11, comprising at least one compound of the compound for an organic electroluminescent device and at least one compound of an indolocarbazole compound having a nitrogen-containing aromatic six-membered ring structure. The material for an organic electroluminescent device according to claim 12, wherein the indolocarbazole compound having a nitrogen-containing aromatic six-membered ring structure is a compound represented by the general formula (8).

Here, ring F represents an aromatic ring represented by the formula (F8) condensed at any position of two adjacent rings. Ring G represents a heterocyclic ring represented by the formula (G8) fused at an arbitrary position on two adjacent rings. Ar in the formula (8) and the formula (G8) is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, Or a substituted or unsubstituted linked aromatic group in which these aromatic rings are linked by 2 to 10, and the other Ar is a nitrogen-containing aromatic 6-membered ring structure-containing group represented by the formula (9). .

Here, Y is represented by N, CH, or CAr ′, and at least one is N. Ar 'is independently a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 16 carbon atoms, or 2 to 10 of these aromatic rings. It represents a substituted or unsubstituted linked aromatic group which is linked.   14. The material for an organic electroluminescent device according to claim 13, wherein in the general formula (8), one Ar is a phenyl group, a biphenyl group, a terphenyl group, or a quaterphenyl group. 14. The material for an organic electroluminescent device according to claim 13, wherein in the general formula (9), Ar ′ is an aromatic hydrocarbon group represented by the formula (10) or a linked aromatic group.

Here, p shows the integer of 0-5.   An organic electroluminescent device comprising an organic layer comprising the material for an organic electroluminescent device according to claim 11.   A composition for an organic electroluminescent device obtained by dissolving or dispersing the material for an organic electroluminescent device according to claim 11 in a solvent.   An organic electroluminescent device comprising an organic layer comprising a coating film of the composition for an organic electroluminescent device according to claim 17.   The organic according to claim 16, wherein the organic layer is at least one layer selected from a light emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a hole blocking layer, and an electron blocking layer. Electroluminescent device.   The organic electroluminescent device according to claim 19, wherein the organic layer is a light emitting layer. The organic electroluminescent device according to claim 20, wherein the light emitting layer contains a light emitting dopant material.

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